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High power pulsed magnetron sputtering A review on scientific and engineering state of the art

High power pulsed magnetron sputtering:A review on scienti ﬁc and engineering state of the artK.Sarakinos a ,⁎,1,J.Alami b ,1,S.Konstantinidis c ,1a Materials Chemistry,RWTH Aachen University,52074Aachen,Germanyb Sulzer Metaplas GmbH,Am Böttcherberg 30-38,51427,Bergisch Gladbach,GermanycLaboratoire de Chimie Inorganique et Analytique,Universitéde Mons,Avenue Copernic 1,7000Mons,Belgiuma b s t r a c ta r t i c l e i n f o Article history:Received 31March 2009Accepted in revised form 6November 2009Available online 19January 2010Keywords:HPPMS HiPIMSIonized PVDHigh power pulsed magnetron sputtering (HPPMS)is an emerging technology that has gained substantial interest among academics and industrials alike.HPPMS,also known as HIPIMS (high power impulse magnetron sputtering),is a physical vapor deposition technique in which the power is applied to the target in pulses of low duty cycle (b 10%)and frequency (b 10kHz)leading to pulse target power densities of several kW cm −2.This mode of operation results in generation of ultra-dense plasmas with unique properties,such as a high degree of ionization of the sputtered atoms and an off-normal transport of ionized species,with respect to the target.These features make possible the deposition of dense and smooth coatings on complex-shaped substrates,and provide new and added parameters to control the deposition process,tailor the properties and optimize the performance of elemental and compound ﬁlms.©2009Elsevier B.V.All rights reserved.Contents 1.Introduction ..............................................................16622.HPPMS:power supplies and processes .................................................16623.Plasma dynamics in HPPMS ......................................................16643.1.On the HPPMS plasma .....................................................16643.2.Determination of plasma properties:a theoretical overview ....................................16653.3.The HPPMS plasma properties ..................................................16663.3.1.The effect of the pulse on/off time con ﬁguration on the plasma properties .........................16683.3.2.Rarefaction in the HPPMS plasma ............................................16693.4.Instabilities in the HPPMS plasma ................................................16713.4.1.Plasma instabilities:an overview ............................................16713.4.2.Plasma initiation and the relationship between plasma instabilities and the chargetransport in the HPPMS plasma .....16714.Plasma-surface interactions and deposition rate .............................................16734.1.Non-reactive HPPMS ......................................................16734.1.1.Target-plasma interactions and target erosion rate ....................................16734.1.2.Transport of ionized sputtered species ..........................................16754.2.Reactive HPPMS ........................................................16755.Growth of thin ﬁlms by HPPMS ....................................................16765.1.HPPMS use for deposition on complex-shaped substrates .....................................16765.2.Interface engineering by HPPMS .................................................16775.3.The effect of HPPMS on the ﬁlm microstructure .........................................16785.4.Phase composition tailoring of ﬁlms deposited using HPPMS ...................................16796.Towards the industrialization of HPPMS ................................................16816.1.Examples of industrially relevant coatings by HPPMS .................................. (1681)Surface &Coatings Technology 204(2010)1661–1684⁎Corresponding author.Tel.:+492418025974,+492204299390,+3265554956.E-mail address:sarakinos@mch.rwth-aachen.de (K.Sarakinos).1All authors have contributed equally to the preparation of themanuscript.0257-8972/$–see front matter ©2009Elsevier B.V.All rights reserved.doi:10.1016/j.surfcoat.2009.11.013Contents lists available at ScienceDirectSurface &Coatings Technologyj o u r n a l h om e p a g e :w w w.e l s ev i e r.c o m /l o c a t e /s u r fc o a t6.2.Up-scaling of the HPPMS process (1682)6.3.Positioning HPPMS in the coating and components market (1682)Acknowledgements (1682)References (1682)1.IntroductionThinﬁlms are used in diverse technological applications,such as surface protection and decoration,data storage,and optical and microelectronic devices.The increasing demand for new functional ﬁlms has been a strong incentive for research towards not only understanding the fundamentals and technical aspects of thinﬁlm growth,but also developing new deposition techniques which allow for a better control of the deposition process.Among the various methods employed forﬁlm growth,Physical Vapor Deposition(PVD)techniques, such as magnetron sputtering,are widely used[1].Magnetron sputtering is a plasma-based technique,in which inert gas(commonly Ar)atoms are ionized and accelerated as a result of the potential difference between the negatively biased target(cathode)and anode.The interactions of the ions with the target surface cause ejection(sputtering)of atoms which condensate on a substrate and form aﬁlm[1,2].The condensation and ﬁlm growth processes frequently occur far from the thermodynamic equilibrium,due to kinetic restrictions[2,3].Thus,a good control of both the thermodynamic and the kinetic conditions has implications on the growth dynamics and enables the tailoring of the structural,optical, electrical,and mechanical properties of theﬁlms[4].One way to control the growth dynamics is by heating the substrate during the deposition [2].The magnitude of the deposition temperature affects the energy transferred to theﬁlm forming species(adatoms)[2].This energy is,for instance,decisive for the activation of surface and bulk diffusion processes[5,6]and enables control over theﬁlm morphology[7–10]. Another source of energy are the plasma particles that impinge onto the growingﬁlm transferring energy and momentum to the adatoms[4,5]. The bombardingﬂux consists both of neutral and charged gas particles,as well as sputtered species.Numerous studies have shown that the energy, theﬂux,the angle of incidence,and the nature of the bombarding species are of importance for the properties of the depositedﬁlms[4,5,11,12].In general,the plasma particles exhibit a relatively broad energy distribu-tion with a mean value of several eV[13].The particle energy,andﬂux are affected by the target-to-substrate distance and the working pressure[1]. When the particles are charged the control of their energy can additionally be achieved by the use of electricﬁelds,e.g.by applying a bias voltage to the substrate[4,14],while theirﬂux depends on a number of factors including the plasma density,the target power,and the magneticﬁeld conﬁguration at the target[4,14].It is therefore evident, that a high ion fraction in a depositingﬂux facilitates a more efﬁcient and accurate control of the bombardment conditions providing,thus,added means for the tuning of theﬁlm properties.In magnetron sputtering processes the degree of ionization of the plasma particles is relatively low[13],resulting in a low total ionﬂux towards the growingﬁlm[13].As a consequence,in many cases bias voltage values of several tenths or even hundreds of V are required in order to increase the average energy provided to the deposited atoms and signiﬁcantly affect theﬁlm properties[5].Moreover,the degree of ionization of sputtered species is typically less than1%[13,15,16].As a result,the majority of the charged bombarding particles is made of Ar+ions[13].This fact in combination with the relatively high bias voltages may cause subplantation of the Ar atoms in theﬁlm[17,18], leading to a generation of lattice defects,[18,19]high residual stresses [20–23],a deterioration of the quality of theﬁlm/substrate interface [21],and a poorﬁlm adhesion[24].Thus,the increase of the fraction of the ionized sputtered species has been an objective of many research works during the recent decades.Some of the approaches that have been demonstrated include the use of an inductively coupled plasma (ICP)superimposed on a magnetron plasma[25],the use of a hollow cathode magnetron[25],and the use of an external ion source[26]. Parallel to the above mentioned approaches Mozgrin et al.[27], Bugaev et al.[28]and Fetisov et al.[29]demonstrated in the mid90s that the operation of a conventional sputtering source in a pulsed mode,with a pulse duration ranging from1µs to1s and a frequency less than1kHz,allowed for pulsed target currents two orders of magnitude higher than the average target current in a conventional sputtering technique,such as direct current magnetron sputtering (dcMS)[27–29].These high pulse currents resulted,in turn,in ultra-dense plasmas with electron densities in the order of1018m−3[27–29],which are much higher than the values of1014–1016m−3 commonly obtained for dcMS[13,30].A few years later,Kouznetsov et al.[31]demonstrated in a publication,that received much acclaim,the high power pulsed operation of the sputtered target showing that in the case of Cu the high plasma densities obtained using this pulsed technique resulted in a total ionﬂux two orders of magnitude higher than that of a dcMS plasma,and a sputtered material ionization of ∼70%.The new deposition technique was called High Power Pulsed Magnetron Sputtering(HPPMS).In the years after Kouzsetov's report, HPPMS received extensive interest from researchers and led to a substantial increase of the HPPMS-related publications(Fig.1).Later, several research groups[25]adopted the alternative name High Power Impulse Magnetron Sputtering(HiPIMS)for this technique.The aim of this review paper is to describe the scientiﬁc and engineering state of the art of HPPMS.For this purpose,the principle and the basic structure of the existing HPPMS power supplies are described and the various existing approaches to produce high power pulses are demonstrated.The spatial and the temporal evolution of the HPPMS plasma and its interactions with the target and the growingﬁlm are discussed both from a theoretical and an experi-mental perspective.Furthermore,the effect of the HPPMS operation on the deposition rate and theﬁlm properties is presented.Finally,the use of HPPMS in industry and the challenges that the latter faces regarding the use of HPPMS are brieﬂy addressed.2.HPPMS:power supplies and processesThe experimental realization of HPPMS requires power supplies different than those used in conventional magnetron sputtering processes. Those power supplies must be able to provide the target with pulses of high power density(typically in the range of a few kW cm−2),while maintaining the time-averaged target power density in values similarto Fig.1.Number of HPPMS-related publications in the period1999–2008.1662K.Sarakinos et al./Surface&Coatings Technology204(2010)1661–1684those during dcMS (i.e.a few W cm −2).The low average target power density is necessary to prevent overheating of the cathode and damage of the magnets and the target.A number of research groups and companies have developed HPPMS arrangements for both laboratorial and industrial use.These devices exhibit similarities in their basic structure which is schematically depicted in Fig.2.A dc generator is used to load the capacitor bank of a pulsing unit,which is connected to the magnetron.The charging voltage of the capacitor bank ranges typically from several hundreds of V up to several kV.The stored energy is released in pulses of de ﬁned width and frequency using transistors with a switching capability in the µs range,located between the capacitors and the cathode.The pulse width (also referred to as pulse on-time)ranges,typically,from 5to 5000µs,while the pulse repetition frequency spans from 10Hz to 10kHz.Under these conditions,the peak target current density may reach values of up to several Acm −2,which are up to 3orders of magnitude higher than the current densities in dcMS [25].The high target current densities during the pulse on-time are accompanied by differences in the electrical characteristics of the discharge,as manifested by the current –voltage (I –V )curves of a magnetron operating in a dcMS and an HPPMS mode (Fig.3).According to Thornton [32]the target and the voltage of the magnetron are linked by the power law I ∝Vnð1ÞIn dcMS processes the exponent n in Eq.(1)ranges from 5up to 15(Fig.3).In HPPMS the exponent n changes from values similar to dcMS at low target voltages to values close to the unity when high voltages are applied (Fig.3)[33,34].Despite their common basic architecture,the available HPPMS power supplies exhibit differences primarily in the width and the shape of the pulses they can deliver,and in whether they can sustain a constant voltage during the pulse on-time.Arrangements able to provide high power pulses were already developed in the mid 90s,in order to explore the feasibility of producing high-current quasi-stationary magnetron glow discharges for high rate deposition [27–29].However,it was in 1999when Kouznetsov et al.[31]emphasizedthat the high power pulsing could allow for a high ionization degree of copper vapor (70%)as well as a homogeneous ﬁlling of 1:2aspect ratio trenches (see Fig.4).The time-dependent target current and target voltage curves of the HPPMS power supply developed by Kouznetsov et al.[31]are plotted in Fig.5where it is shown that the ignition of the plasma is accompanied by a drop of the voltage from ∼1000V to ∼800V,as the current increases to its peak value ranging from 200to 230A at the highest applied working pressure [35,36].A characteristic of this power supply is that the loading voltage is not maintained constant during the pulse on-time,and its temporal evolution is rather determined by the size of the capacitor bank and the time-dependent plasma impedance.Other power generators were designed to deliver voltage pulses with a rectangular shape (see Fig.6),i.e.a constant voltage value during the pulse on-time [34,37–39].It is to be noted that pulses with widths larger than about 50µs allow for a saturation of the discharge current and establishment of a steady-state plasma [40]provided that enough energy is stored in the capacitor bank.A common problem encountered in sputtering processes is the occurrence of arcs.This phenomenon is particularly pronounced during the deposition from conducting targets covered by insulating layers and can be detrimental for the quality of the ﬁlms,due to the ejection of µm sized droplets from the target [41,42].The high peak target currents during the HPPMS operation may enhance the frequency of the arc events [43].Therefore,sophisticated electronics can be used in conjunction with the HPPMS power supplies to limit their effect if formed [43].An alternative way to alleviate this problem is to operate HPPMS using short pulses with widths ranging from 5to 20µs [44].A waveform during this mode of operation is presented in Fig.7.Within this short period of time,the glow discharge remains in a transient regime [40](as manifested by the triangular form of the target current)so that an eventual glow-to-arc transition is prevented.These short pulses have been,for instance,shown to allow for a stable and an arc-free reactive deposition of metal oxide ﬁlms [45,46].However,in order to eliminate the time lag for plasma ignition which would allow for the production of high-current pulses within this short period of time,a pre-ionization stage has to be implemented [44,47].The pre-ionization of the discharge ensures that a low density plasma is maintained between the pulses as the charge carriers are already present before the voltage is turned on.The plasma pre-ionization step may be achieved by super-imposing a secondary plasma (such as a dc,a microwave,or an inductively coupled plasma)on the HPPMS plasma or by running the discharge at relatively high frequencies [44,47–49].The latter pre-ionization method is extensively implemented in mid-frequency pulsed plasmas [50–53].In contrast to the short pulses described above,long pulses with a width of several thousands of µs can also be used [54](Fig.8).In this case the pulse is composed of two (or more)stages.TheFig.2.Basic architecture of an HPPMS power supply.The dc generator charges the capacitor bank of a pulsing unit.The energy stored in the capacitors is dissipated into the plasma in pulses of well-de ﬁned width and frequency using ultra fastswitches.Fig.3.Current –voltage curves of a magnetron during operation in dcMS and HPPMS mode.The change of the slope from 7to 1at a voltage value of 650V indicates loss of the electron con ﬁnement (data taken from [33]).Fig. 4.Cross-section SEM image of two via holes with an aspect ratio 1:2homogeneously ﬁlled by Cu using HPPMS (reprinted from [31]after permission,1999©Elsevier).1663K.Sarakinos et al./Surface &Coatings Technology 204(2010)1661–1684ﬁrst step of the discharge is made of a weakly ionized regime,while the second part of the pulse brings the glow discharge to the high ionization state.The weakly ionized regime allows for the formation of a stable discharge prior to entering the highly ionized regime which helps to suppress the arc formation during the high power mode of operation [54].3.Plasma dynamics in HPPMS 3.1.On the HPPMS plasmaPlasmas are partially ionized gases characterized by,for example,the charge (electron)density or the electron energy distribution function [55].A classi ﬁcation of different plasmas could be based on the charge density as shown in Fig.9,where the magnetron sputtering plasmas are shown to exhibit densities ranging from ∼1014up to 1020m −3.It is known that high density plasmas such as arc plasmas exhibit high ionization fractions [25,31].This is not the case for conventional magnetron plasmas where the electron density does not exceed the value of 1016m −3,penning ionization is the main ionization mechanism [30]and therefore the ionization of the sputtered species is at the best of few percent [13].In order to achieve a high ion fraction in a discharge it is necessary to promote the electron impact ionization [55]which is best realized by increasing the electron density and temperature.Different approaches have been made to achieve this,for example by using an electron cyclotron resonance (ECR)plasma as a plasma electron source [56],or by employing an inductively coupled plasma (ICP)[57,58].A higher frequency of electron impact ionization collisions can alsobeFig.5.Target current and voltage waveforms produced by the power supply developed by Kouznetsov et al.at working pressures of (a)0.06Pa,(b)0.26Pa,(c)1.33Pa and (d)2.66Pa.The charging voltage of 1000V drops down to 800V and the plasma is ignited.Peak target currents of up to 230A are achieved.The time lag for the ignition of the plasma decreases when the pressure is increased (reprinted from [35]after permission,2002©Elsevier).Fig.6.Rectangular shape voltage waveforms generated by the HPPMS power supply developed by MELEC GmbH.The data were recorded from an Ar –Al HPPMS discharge operating at pulse on/off time con ﬁguration 25/475µs (K.Sarakinos,unpublisheddata).Fig.7.Temporal evolution of target voltage and current during operation using a 10µs long pulse.The target current is interrupted before the plasma enters into the steady-state regime.The data were recorded from an Ar –Ti HPPMS discharge (S.Konstantinidis unpublished data).1664K.Sarakinos et al./Surface &Coatings Technology 204(2010)1661–1684achieved by increasing the power to the sputter source and therewith the electron density.This approach is,however,limited since a power excess can result in an overheating of the target or an exceeding of the Curie temperature of the magnetron's magnets.Thus,the work of Kouznetsov et al.[31]opened a new era of magnetron sputtering deposition and plasma studies,since it allowed for the generation of highly ionized plasmas using a conventional magnetron source.The early analyses of the HPPMS plasma showed that its temporal characteristics are complex and unique [35,59,60].Understanding the discharge evolution and the mechanisms that take place in the plasma is therefore of utmost importance as this sheds light on the growth conditions during the thin ﬁlm deposition.To achieve this,modeling and a number of analytical studies have been carried out,using Langmuir probes as well as optical emission,mass,and absorption spectroscopy techniques.These studies are reviewed in the following chapters and the basic properties of the HPPMS plasma are thus outlined.3.2.Determination of plasma properties:a theoretical overview Plasmas are commonly modeled as ﬂuids,and each species is described with its ﬂuid equation [61].The ﬂuid approximation is suf ﬁciently accurate to describe the majority of observed plasma phenomena.When this is not viable,the accumulated behavior of anensemble of charged particles is described using a statistical approach,in the form of the velocity distribution function which is given as f (r,u,t )d 3r d 3u ,i.e.the number of particles inside a six-dimensional phase space volume d 3r d 3u at (r ,u )and time t [55].Here,r is the position vector and u is the speed vector.Knowing the distribution function,fundamental features of a large ensemble can be quanti ﬁed,i.e.by integrating over the velocity,the average (macroscopic)quantities associated with the plasma are de ﬁned as:n ðr ;t Þ=∫f ðr ;u ;t Þd u plasmanumber ðion ;electron ;orneutral Þdensityð2Þu Àðr ;t Þ=1n∫u f ðr ;u ;t Þd u plasmabulkfluid velocity ð3ÞεÀðr ;t Þ=m 2n∫ðu À−u Þ2f ðr ;u ;t Þd u plasmameankineticenergy ð4Þwhere m is the particle (ion,electron,or neutral)mass.This procedure of integrating over velocity space is referred to as taking velocity moments,with each one yielding a physically signi ﬁcant quantity.Knowledge of the electron energy (velocity)distribution function (EEDF)permits us to determine important parameters.The EEDF can be measured using a Langmuir probe,as was demonstrated by Druyvesteyn [55]:g e ðV Þ=2m e A pr 2eV m12d 2I edV ð5Þwhere A pr is the probe area,I e is the electron current,m is the electronmass,and V =V pl −V b is the potential difference between the plasma potential and the probe potential.With the change of variables ε=eV ,the electron density n e is determined as:n e =∫∞0g e ðεÞd εð6ÞPlasma parameters,such as the electron density,are easily obtained if the mathematical description of the EEDF is Maxwellian.The Maxwellian distribution is characterized by its single temperature and is obtained when plasma electrons undergo enough collisions and are in equilibrium with other plasma components and with the electron ensemble itself.At a low pressure,the EEDF is generally non-Maxwellian,and the electron temperature is thought of as aneffectiveFig.8.Target voltage and current waveforms during the long-pulse operation.In the ﬁrst 500µs a weakly ionized plasma is generated which is followed by a highly ionized steady-state plasma (reprinted from [54]after permission,Society of Vacuum Coaters ©2007).Fig.9.Plasma density is used in order to classify plasmas.The HPPMS plasma spans over a large density range depending on the pulse on/off time con ﬁguration used for a process and presents therefore a tool for better choosing the plasma dynamics needed for the deposition process.The abbreviation ECR stands for Electron Cyclotron Resonance (taken from [36]).1665K.Sarakinos et al./Surface &Coatings Technology 204(2010)1661–1684electron temperature,T eff∼23〈ε〉,representing the mean electron energy determined from the EEDF according to[55]:〈ε〉=1n e ∫∞εg eðεÞdεð7Þ3.3.The HPPMS plasma propertiesOne of the earliest works related to the study of the properties of the HPPMS plasma was carried out by Gudmundsson et al.[35,59]. Using a Langmuir probe[62]in an Ar–Ta plasma,they measured the temporal behavior of the EEDF by recording the time-dependent probe current curves.It was shown that the EEDF evolved from a Druyvesteyn-like distribution with a broad energy distribution(high average energy)during the pulse to a double Maxwellian distribution (i.e.a distribution that is composed of two-distinct energy-distribu-tions)toward the end of the pulse,andﬁnally a Maxwellian-like distribution hundreds ofµs after the pulse had been switched off.This is shown in Fig.10,where the temporal evolution of the EEDF is also seen to be affected by the working pressure[35].Similar results were obtained by Pajdarova et al.[63],although the double Maxwellian distribution was observed from the beginning of the pulse,which could be explained by the nature of the target material(Cu in this case)and the HPPMS parameters used in the experiments.Further-more,it was found that the effective electron temperature peaked a fewµs after the pulse start,and at the same time,independent of measurement position[35].This is indicative of the existence of high energy electrons accelerated by the target voltage,and thus escaping the conﬁnement region in the vicinity of the cathode[35].InaFig.10.The EEDF(electron energy distribution function)for an HPPMS plasma with a100µs on-time and a50Hz frequency at three chamber pressures(a)0.25,(b)1.33,and(c) 2.66Pa.The distribution function changes during the pulse from a Druvesteyn distribution to a double-Maxwellian distribution(reprinted from[35]after permission,Elsevier©2002).1666K.Sarakinos et al./Surface&Coatings Technology204(2010)1661–1684different study by Seo et al.[64],Langmuir probes were utilized to determine the properties of a HPPMS plasma at a higher pulsing frequency of 10kHz and a duty cycle of 10%.By using such a high frequency,the electron density reached a value of 1.5×1017m −3,which could be seen as a relatively low density HPPMS plasma.The temporal evolution of the energy distribution in this plasma showed ef ﬁcient electron heating,which took place within the ﬁrst few µs from the pulse start.This work revealed that the plasma dynamics presented in the studies by Gudmundsson et al.[35,59]are to a large extent general features of the low duty cycle pulsed plasmas regardless of the frequency.The early studies on the HPPMS plasma characteristics also showed the potentially high ionization fraction of the sputtered material that could be achieved by using this technique [16,25,33,60,65,66].Spectroscopic analyses,such as optical emission spectroscopy [67–69],mass spectroscopy [69],and absorption spectroscopy [68,69]were,therefore,employed in order to better quantify and understand the average and time-dependent evolution of the ion population in the HPPMS plasma.The optical emission studies [33,65,70–72],were performed both for the HPPMS and the dcMS discharges and showed the much higher metal ion emission intensity in HPPMS (Fig.11).However,in order to better quantify these observations,absorption spectroscopy [70,71,73,74]and mass spectroscopy [75,76]studies were performed,con ﬁrming the much higher ionization of the sputtered material and of the sputtering gas achieved in HPPMS.One well studied material in this regard is Ti.Mass spectroscopy measurements of the peak ion compositions in an Ar –Ti discharge for the pulse on-time of 100µs and a frequency of 50Hz [75]showed that the ionized part of the plasma contained 50%of Ti 1+,24%of Ti 2+,23%of Ar 1+,and 3%of Ar 2+ions.When longer pulse on-times of several hundreds of µs were used even Ti 3+and Ti 4+could also be detected [77].It is deduced that for the formation of multiply charged ions certain conditions should be ful ﬁlled [77];(i)the discharge should contain a high enough number of metal ions,(ii)the pulse on-time should be long enough (and the capacitance of the used power supply should be large enough to store enough energy for the whole pulse),(iii)the self-sputtering yield (i.e.the sputtering yield of the target material from ionized target species)should be low,and (iv)the ionization energy of each ionization step should not be too high.These two examples show clearly that the HPPMS plasma properties depend not only on the plasma density and energy distribution but also,to a large degree,on the pulse on/off time con ﬁguration.Since the introduction of the HPPMS technique,most of the discharge studies have been performed for pulses with pulses on-time longer than 50µs.Exceptions to this can be found in the works by Konstantinidis et al.[70,73],Ganciu et al.[44],and Vasina et al.[48],where shorter pulses ranging between 5and 30µs have been used,an example of which is shown in ing time-resolved optical emission spectroscopy in a Ti –Ar discharge,an increase in the line intensity ratio of the ion-to-neutral Ti and Ar species with increasing the pulse duration was observed [70].This means that the ionization degree increases with increasing pulse length,indicating the necessity for the sputtered atoms to reside a suf ﬁcient time in the target vicinity for the vapor to become ionized.The increase of the AremissionFig.11.Optical emission spectroscopy from a typical HPPMS plasma.The emission from the Ti and Ar species increases greatly in HPPMS indicating the high ionization of the metal and gas species (data taken from [72]).Fig.10(continued ).1667K.Sarakinos et al./Surface &Coatings Technology 204(2010)1661–1684。

V alidation of high-performance liquid chromatography methods for

2. Step by step to establish method validation plan The ﬁrst step in the development of a method validation protocol is to determine the objective of the method. How will the method be used? What is the method intended to demonstrate? Based on the response to these questions, there will be at least two main choices. For example, if the method is intended to monitor patients, release ﬁnal product, or determine potency, level of impurity, or contaminants in a human drug product, the method is considered a Level I (quantitative assay). If the method is intended to serve as a qualitative evaluation for identity, the method is considered a Level II. Is the method to be used for establishing a limit of impurity (less than or greater than a standard)? Are the results visual? In all cases, the following additional questions will also need to be answered: What sampletypes will be tested using the method? Will the samples be whole blood, serum, plasma, puriﬁed protein, unpuriﬁed protein, chemical agents, etc.? Based on the sample-type, what interferences are expected? Is it likely that those interfering substances will impact the results? Is the method cell-based, chemical-based or enzyme-based? What level of accuracy, precision, sensitivity and limit of detection is required? Analyte concentration range for these validation parameters are given in Sections 4.1–4.4, respectively. The goal of the questions and the preliminary evaluation is to determine how best to meet the objective of the method validation so that it

Effect of fly ash fineness on microstructure of blended cement paste

Eﬀect of ﬂy ash ﬁneness on microstructure of blended cement pastePrinya Chindaprasirt a ,Chai Jaturapitakkul b ,Theerawat Sinsiric,*aDepartment of Civil Engineering,Faculty of Engineering,Khon Kaen University,Khon Kaen 4002,ThailandbDepartment of Civil Engineering,Faculty of Engineering,King Mongkut’s University of Technology Thonburi,Bangkok 10140,Thailand cSchool of Civil Engineering,Institute of Engineering,Suranaree University of Technologi,Nakorn Ratchasima 30000,ThailandReceived 1May 2005;received in revised form 20November 2005;accepted 5December 2005Available online 6October 2006AbstractThis research demonstrates the eﬀect of ﬂy ash ﬁneness on pore size and microstructure of hardened blended cement pastes.Two sizes of ﬂy ash,original ﬂy ash and classiﬁed ﬂy ash were used to replace Portland cement type I paste.Test results indicated that the pore sizes of hardened blended cement paste were signiﬁcantly aﬀected by the rate of replacement and the ﬁneness of ﬂy ash.The replacement of cement by original ﬂy ash decreased the pore sizes of blended cement paste and the incorporation of classiﬁed ﬂy ash resulted in a further decrease in the pore sizes of blended cement paste.The X-ray diﬀraction (XRD)results showed that the blended cement paste with clas-siﬁed ﬂy ash was more eﬀective at reducing the intensity of Ca(OH)2than that with the original ﬂy ash.The scanning electron microscope (SEM)results revealed that the hardened blended cement paste containing ﬁner ﬂy ash produced a denser structure than the one con-taining coarser ﬂy ash.Ó2006Elsevier Ltd.All rights reserved.Keywords:Fineness;Fly ash;Pore size;Microstructure;Blended cement paste1.IntroductionConcrete is a composite material which has a complex microstructure and exhibits a wide range of scale lengths from nanometers to millimeters [1].Aggregates are the big-gest materials in concrete and have particle size in millime-ters.At the micrometer scale,the cement paste is a composite of unhydrated residues of cement grains and hydration products (C–S–H,Ca(OH)2,and capillary pore).Hydrated cement paste contains large capillary pores with diameters between 50–10,000nm,medium capillary pores with diameters of 10–50nm and gel pores with diameter of less than 10nm [2].It is well known that the service life of a concrete structure is strongly dependent on its material transport properties,which are controlled by the micro-structure characteristics of concrete.It is generally recog-nized that the incorporation of pozzolanic materials as a partial replacement for Portland cement in concrete is aneﬀective means for improving the properties of concrete.Pozzolanic materials react with calcium hydroxide during hydration reaction and forms calcium silicate hydrate.This can reduce the size of the pores of crystalline hydration products,make the microstructure of concrete more uni-form and improve the impermeability and durability of concrete.These improvements can lead to an increase in the service life of a concrete structure.Fly ash is a waste product from the combustion of pul-verized coal in electricity power plants.It is estimated that more than 3.5million tons of ﬂy ash has been produced annually in Thailand since 2001,however,only half has been utilized.The utilization of ﬂy ash is still limited due to lack of understanding of the characteristics of ﬂy ash itself and the properties of concrete containing ﬂy ash.Many researchers have already reported on the inﬂuence of ﬂy ash on the properties of concrete such as compressive strength,sulfate resistance,durability and so on.However,few researches were found,which deal with the ﬁneness of ﬂy ash on pore structure and microstructure of blended cement paste.An understanding of the inﬂuence of ﬁneness0950-0618/$-see front matter Ó2006Elsevier Ltd.All rights reserved.doi:10.1016/j.conbuildmat.2005.12.024*Corresponding author.Tel.:+66442244201;fax:+6644224220.E-mail address:sinsiri@sut.ac.th (T.Sinsiri)./locate/conbuildmatConstruction and Building Materials 21(2007)1534–1541Construction and BuildingMATERIALSof ﬂy ash on pore structure and microstructure of cement paste could lead to an increase in the use of ﬂy ash in con-crete.In this paper,pore structure and microstructure of ﬂy ash cement pastes with diﬀerent ﬂy ash ﬁnenesses are investigated.2.Experimental program 2.1.Material propertiesFly ash from Mae Moh power plant in the north of Thailand,Portland cement type I (PC)and tap water were used in this study.The chemical composition of Portland cement type I (PC),original and classiﬁed ﬂy ashes (OFA and CFA)are given in Table 1.The total amount of the major components SiO 2,Al 2O 3,and Fe 2O 3in OFA and CFA are 81.54%and 79.44%,respectively.They can be classiﬁed as class F ﬂy ash in accordance with ASTM C 618.It should be noted that there is no signiﬁcant diﬀerence in the chemical composition of OFA and CFA.Two ﬂy ash sizes of OFA with median particle size of 19.1l m and CFA with median particle size of 6.4l m were used to replace Portland cement.Physical properties of PC,OFA,and CFA are shown in Table 2and particle size distributions are shown in Fig.1.Particle shapes of PC,OFA,and CFA by SEM are shown in Fig.2.The X-ray diﬀraction patterns (XRD)of OFA and CFA are shown in Fig.3.There is little diﬀerence between the XRD patterns of OFA and CFA.It is known that ﬂy ashes consists of a glassy matrix with crystalline phases like quartz,mullite,hematite,anhydrite,lime,and so on.In the Mae Moh ﬂy ash,quartz is commonly found as the crystalline compound in OFA and CFA.In addition,traces of hematite and mullite are also noticeable.Chindaprasirt et al.[3]studied the glassy phase content of the Mae Moh ﬂy ash and found that the glassy phase content ofthe ﬁne ﬂy ash (about 85–90%)was higher than that of the coarser ﬂy ash (about 70–75%).This result agreed with Berry et al.[4],who showed that the glassy phase was found to increase in the ﬁne ﬂy ash as compared to the ori-ginal ﬂy ash.2.2.Mix proportionFly ashes were used to replace Portland cement at the rate of 0,20,and 40%by weight of binder.The water to binder ratio (W/B)was constantly 0.35throughout the investigation.The pastes were mixed in a mechanical mixer and were cast in 50mm cube molds and compacted by tamping rod,and were sealed by plastic to prevent water loss.24h after casting,specimen were removed from the molds and cured in saturated lime water.2.3.Mercury intrusion porosimetryMeasurement on pore size distribution of paste was car-ried out using mercury intrusion porosimeter (MIP)with a pressure range from 0to 33,000psi (228MPa),capable of measuring pore size diameter down to 5.7nm.By carefully breaking the hardened blended cement paste cubes with a chisel,the representative samples of 3–6mm pieces weigh-ing between 1and 1.5g were taken from the middle of the specimen.The samples were frozen at À195°C by immer-sion in liquid nitrogen for 5min and evacuated at a pres-sure of 0.5Pa at À40°C for 48h [5–7].Mercury porosimetry is expressed by the Washburn equation [8].A constant contact angle of 140°and a constant surfaceTable 1Chemical composition of PC type I and ﬂy ashes Chemicalcomposition (%)Portland cement type I Original ﬂy ash Classiﬁed ﬂy ash SiO 220.9045.6944.72Al 2O 3 4.7624.5923.69Fe 2O 3 3.4111.2611.03CaO 65.4112.1512.67MgO 1.25 2.87 2.63SO 3 2.71 1.57 1.28Na 2O 0.240.070.07K 2O 0.35 2.66 2.87LOI0.961.231.42Table 2Physical properties of PC type I and ﬂy ashes SampleMedian particle size (l m)Retained on a sieve No.325(%)Speciﬁc gravity Blaine ﬁneness (m 2/kg)Portland cement type I 14.1 4.8 3.15360Original ﬂy ash 19.131.0 2.33300Classiﬁed ﬂy ash6.42.54510P.Chindaprasirt et al./Construction and Building Materials 21(2007)1534–15411535tension of mercury of 480dynes/cm were used for pore size calculation by,D ¼Àð1=P Þ4c cos uð1Þwhere D is the pore diameter (l m),P is the applied pressure (MPa),c is the surface tension (dynes/cm),and u is the contact angle (degree).2.4.X-ray diﬀraction (XRD)The hydration of cement pastes containing ﬂy ashes,with an increased intensity of Ca(OH)2,were investigated by XRD analysis.All samples were cured for 28,60and90days.At speciﬁed ages of 28,60and 90days,samples from the crushed paste cubes and freeze-dried samples were tested for degrees of hydration,as prepared in the MIP examination.The dried sample pastes were ground using a ball mill and sieved through a sieve No.100(opening 150l m).The powder sample weighing about 1g was used to determine the amount of Ca(OH)2in the XRD analysis (Bruker D5005).2.5.Scanning electron microscope (SEM)Paste cubes at the required ages of 7,28and 90days were broken from the center into small fragments.Hydra-tion of the paste was stopped by freezing and drying,as prepared in the MIP examination.The fracture surface was observed by using SEM (JOEL JSM-6400).All sam-ples were also coated with gold before using SEM analysis.3.Results and discussion3.1.Eﬀect of ﬂy ash ﬁneness on pore size distribution of blended cement pasteRelationships between pore diameter and incremental pore volumes of OFA paste at 28and 90days are shown in Figs.4and 5.Figs.6and 7show the relationships between pore diameter and incremental pore volumes of CFA paste at 28and 90days.At 28days,the ﬁrst peak of capillary pores of CFA20and CFA40pastes were located at 50.4nm with the incremental pore volume of 0.0266ml/g and 44.7nm with incremental pore volume of 0.0195ml/g,Fig.2.SEM of PC type I and ﬂy ashes (a)PC type I (b)Original ﬂy and (c)Classiﬁed ﬂy ash.1536P.Chindaprasirt et al./Construction and Building Materials 21(2007)1534–1541respectively (Fig.6).These values were lower than those of OFA20and OFA40pastes which were 54.5nm at 0.026ml/g at the ﬁrst peak and 55.1nm at 0.019ml/g at the second peak,respectively,with the same replacement (Fig.4).These results suggest that classiﬁed ﬂy ash is more eﬀective for decreasing capillary pores than original ﬂy ash.In Fig.7,there are three visible peaks of incremental pore volume;two peaks in the range of capillary pore and one in the range of gel pore.The peak of pore diameter of CFA20paste decreased from 50.4nm with 0.0266mL/g (at 28days,as shown in Fig.6)to 29.00nm with 0.0204mL/g for the ﬁrst peak and 15.3nm with 0.0114mL/g for the second peak at 90days.The peaks of pore diameter of CFA20and CFA40pastes were smaller than those of OFA20and OFA40pastes.These results sug-gest that the higher the ﬁneness of ﬂy ash,the more eﬀec-tive for reducing the pore diameter of the paste.The results also show that blended cement paste containing ﬂy ash has a smaller pore size than PC paste.The pore size decreased with an increase in ﬂy ash replacement.Similar results were also reported else where [9–11].As demonstrated,the incorporation of classiﬁed ﬂy ash in cement paste resulted in lower pore size compared with the use of original ﬂy ash.This is due to the gradual ﬁlling of large pores from factors such as hydration reaction,nucleation eﬀect,packing eﬀect,and pozzolanic reaction of ﬂy ash particles.The hydration reaction occurs from the chemical constituents in cement and water while the pozzolanic reaction occurs from the reaction of Ca(OH)2with SiO 2and Al 2O 3from ﬂy ash.The smaller spherical particle of ﬂy ash could be easily dispersed into the blended cement paste and made the cement paste matrix more homogeneous.The packing of the ﬁne,solid and spheri-cally shaped ﬂy ash particles that were not completely reacted,ﬁlled the voids and allowed denser packing within the particle of materials and matrix phase [12,13].The nucleation eﬀect,when the smaller particles were dispersed into blended cement paste,accelerated the reactions and formed a smaller product of the cementing paste [14,15].P.Chindaprasirt et al./Construction and Building Materials 21(2007)1534–154115373.2.XRD analysisFig.8shows the XRD patterns of PC,20OFA and 20CFA pastes at 28days while the XRD patterns of PC,40OFA and 40CFA pastes at the same age are shown in Fig.9.It is easily noticed that CH or Ca(OH)2is one of the hydration products during the hydration reaction.The intensity peaks of Ca(OH)2appeared at 2h of 18.07,28.75,34.13,47.12,and 50.85degree.From the results of Figs.8and 9,the intensity peaks of Ca(OH)2in the XRD patterns of the blended cement paste with ﬂy ashes were almost similar to that of PC paste.At early ages (28days),this result supported the hypothesis that the hydra-tion reaction was a dominant phase while the reactivity of ﬂy ash was minimal [16–19].The XRD patterns of PC,OFA,and CFA pastes at 60and 90days are shown in Figs.10–13.The results show that the intensity peaks of Ca(OH)2in the XRD patterns decreased when ﬂy ashes were incorporated into the blended cement paste.In particular,the classiﬁed ﬂy ash was more eﬀective for decreasing the intensity peak of Ca(OH)2than the original one,especially at 90days.It iswell known that Ca(OH)2consumption in a blended cement paste is related to the degree of pozzolanic reaction.Factors aﬀecting the pozzolanic reactivity are ﬁneness and the glassy phase content of the ﬂy ash.Fly ash with a high1538P.Chindaprasirt et al./Construction and Building Materials 21(2007)1534–1541percentage of glassy phase tends to be more reactive than those with a less percentage of glassy phase [20].This indi-cated that the classiﬁed ﬂy ash,which had a smaller size and higher glassy content,had a larger surface area to pro-vide the silica and alumina compounds for higher pozzola-nic activity than the original ﬂy ash.The compounds reacted and consumed Ca(OH)2,resulting in a decrease in Ca(OH)2content.The ﬁner ﬂy ash had a more glassy content resulting in a higher consumption of Ca(OH)2.These results conform to Berry et al.[4],Sybertz and Wiens[21],and Harris et al.[22].It was also noticeable that Ca(OH)2decreased signiﬁcantly with the increase in ﬂy ash content (40%replacement).This phenomenon was con-sidered to be the result of two factors:the large quantity of ﬂy ash used to replace cement resulted in an adequate level of reaction,and high ﬁneness of ﬂy ash allowed pozzolanic reaction to react faster.3.3.SEM observationsThe microstructure morphology of fractured surface pastes at 7,28and 90days are shown in Figs.14–17.At 7days,the microstructures of OFA20and OFA40pastes (Figs.14a and 15a)were porous and had many voids.It can be seen that the hydration products on the ﬂy ash sur-face hardly proceeded,some of the surfaces of ﬂy ash par-ticles were found to be coated with layers of small amounts of hydration products.Some of the ettringite needles,which grow in vacant areas in paste,were occurring.Signif-icantly,the pozzolanic reaction of ﬂy ash in concrete started after one or more weeks [12,19,21].In this period,two mechanisms of hydration and nucleation occupied simultaneously [23–25].Considering OFA20and OFA40pastes at 28days (Fig.14b and Fig.15b),ﬂy ash particles were observed in three forms:particles with a dissolved surface,smooth surface,and a covering layer made of hydration product and pozzolanic reaction.In the ﬁrst form,it appeared thatFig.15.Fractured surface of OFA40paste by SEM.Fig.14.Fractured surface of OFA20paste by SEM.P.Chindaprasirt et al./Construction and Building Materials 21(2007)1534–15411539some ﬂy ash particles had signs of etching on their sur-face,indicating precipitation in the pozzolanic reaction [19,23,25].The second form showed some ﬂy ash particles were still smooth,suggesting that they were unreacted or acted as an inert material with the ability to increase the packing eﬀect and served as a precipitation nucleus for hydration compounds.In the third form,hydration and pozzolanic products around the ﬂy ash particles were observed.At 90days (Fig.14c and Fig.15c),etched ﬂy ash parti-cles and hydrated rims with broken ﬂy ash surfaces were quite common.A lot of ﬂy ash particles were substituted by hydrates,when the ﬂy ashes were activated by Ca(OH)2.The pozzolanic reaction of ﬂy ash speeded up at the later ages and the consumed content of C–S–H increased.The surface of ﬂy ash particles covered by C–S–H were caused by the reaction of ﬂy ash and Ca(OH)2and other hydration products [23,25,26].As the process continued,the layer on the ﬂy ash and cement grain thickened.The hydration products growing from the cement grains and ﬂy ash par-ticles are to be connected,although some particles still remain unreacted and acted as ﬁlling eﬀects [27,28].For classiﬁed ﬂy ash pastes,as shown in Figs.16and 17,the results are similar to that obtained from original ﬂy ash pastes.More empty pores were evident in the pastes at 7and 28days (Figs.16and 17a,b).Another ﬁnding was that a lot of ﬂy ash particles still had smooth surfaces at these ages.As previously explained,they were still unreacted atthe early age and acted as a ﬁller material,serving as a pre-cipitation nucleus for Ca(OH)2and C–S–H gel and ﬁlling the voids between particles of ﬂy ash and cement grain.The ﬁner ﬂy ashes reduced the pore sizes and provided higher numbers of nucleation sites for the hydration prod-ucts than those of original ﬂy ash.At 90days (Fig.16c and Fig.17c),the pastes had a denser structure.The change in pore size of pastes with age was a result of the growth of hydration and pozzolanic products.At this age,the pozzo-lanic reaction on some ﬂy ash particles was discernible from the broken surface of ﬂy ash particle.It was seen that the observed particles had a smooth surface even though they were embedded in the paste for a long time.It was evi-dent that although the matrix had not been fully developed it still underwent the product of either pozzolanic reaction or hydration.From these results,it is concluded that the blended cement paste containing ﬁner ﬂy ash produces a denser structure than that of the paste with the coarser ﬂy ash.4.ConclusionsBased on the results obtained,the following conclusions can be drawn.1.The blended cement paste containing original ﬂy ash generally exhibited a lower pore size than that of Port-land cement type Ipaste.Fig.16.Fractured surface of CFA20paste bySEM.Fig.17.Fractured surface of CFA40paste by SEM.1540P.Chindaprasirt et al./Construction and Building Materials 21(2007)1534–15412.The blended cement paste containing classiﬁedﬂy ashresulted in a lower pore size than that of the one with originalﬂy ash.3.The intensity peak of Ca(OH)2of blended cement pastecontainingﬂy ash decreased with an increase inﬂy ash content andﬁneness.4.The hydration reaction,pozzolanic reaction,packingeﬀect,and nucleation eﬀect were enhanced by the incor-poration ofﬁnerﬂy ash.As a result the paste becomes more homogenous,denser in structure and lower Ca(OH)2than the paste with the coarserﬂy ash.AcknowledgementsThe authors gratefully acknowledge theﬁnancial sup-ports from the Thailand Research Fund(TRF)who spon-sored the research under the Royal Golden Jubilee Ph.D. program and the Ministry of Education of Thailand under the Ministry StaﬀDevelopment Project.We also thank the Department of Civil Engineering,King Mongkut’s Univer-sity of Technology Thonburi and Suranaree University of Technology for providing facilities and equipments. References[1]Garboczi putation materials science of cement-based mate-rials.Mater Struc1993;26:191–5.[2]Mindess S,Young JF.Concrete.Englewood Cliﬀs,N.J.:Prentice-Hall Inc.;1981.[3]Chindaprasirt P,Ruangsiriyakul S,Cao HT,Bucea L,Inﬂuence ofMae Mohﬂy ashﬁneness on characteristics,strength and drying shrinkage development of blended cement mortars,In:The eighth East Asia–Paciﬁc conference on structural engineering and construc-tion,Singapore,5–7December,2001,Paper No.1191.[4]Berry EE,Hemmings RT,Langley WS,and Carette GG,Beneﬁciatedﬂy ash:hydration,microstructure,and strength development in portland cement systems,In:V.M.Malhotra(Ed.),Third CANMET/ ACI,conference onﬂy ash,silica fume,slag,and natural pozzolans in concrete(SP-114),Detroit,1989,p.241–73.[5]Galle C.Eﬀect of drying on cement-based materials pore structure asidentiﬁed by mercury intrusion porosimetry:A comparative study between oven,vacuum,and freeze-drying.Cem Concr Res 2001;31:1467–77.[6]Konecny L,Naqui SJ.The eﬀect of diﬀerent drying techniques on thepore size distribution of blended cement mortars.Cem Concr Res 1993;23:1223–8.[7]Kumar A,Roy DM.The eﬀect of desiccation on the porosity andpore structure of freeze dried hardened portland cement and slag-blended pastes.Cem Concr Res1986;16:74–8.[8]Washburm EW.Note on method of determining the distribution ofpore size in porous materials.P Natl Acad Sci USA1921;7:115–6.[9]Poon CS,Lam L,Wong YL.Eﬀect ofﬂy ash and silica fume oninterfacial porosity of concrete.ACI Mater J1999:197–205.[10]Pandey SP,Sharma RL.The inﬂuence of mineral additions on thestrength and porosity of OPC mortar.Cem Concr Res2000;31:19–23.[11]Poon CS,Wong YL,Lam L.The inﬂuence of diﬀerent curingconditions on the pore structure and related properties ofﬂy ash cement pastes and mortars.Constr Building Mater1997;11(7–8): 383–93.[12]Isaia GC,Gastaldini ALG,Moraes R.Physical and pozzolanic actionof mineral additions on the mechanical strength of high-performance concrete.Cem Concr Compos2003;25:69–76.[13]Mehta PK,Aitcin PC.Principle underlying production of high-performance concrete.Cem Concr Aggr1990;12:70–8.[14]Gopalan MK.Nucleation and pozzolanic factors in strength devel-opment of class Fﬂy ash concrete.ACI Mater J1993;90:117–21. [15]Montgomery DG.Fly ash in concrete–A microstructure study.CemConcr Res1981;11:591–603.[16]Li S,Roy DM,Kumar A.Quantitative determination of pozzolanasin hydrated systems of cement or Ca(OH)2withﬂy ash or silica fume.Cem Concr Res1985;15:1079–86.[17]Dhir RK,Hubbard FH,Munday JGL,Jones MR,Duerden SL.Contribution of PFA to concrete workability and strength develop-ment.Cem Concr Res1988;18:277–89.[18]Marsh BK,Day RL.Pozzolanic and cementitious reactions ofﬂy ashblended cement pastes.Cem Concr Res1988;18:301–10.[19]Fraay ALA,Bijen JM,de Haan YM.The reaction ofﬂy ash inconcrete:A critical examination.Cem Concr Res.1989;19:235–46.[20]Jun-Yuan H,Scheetz BE,Roy DM.Hydration ofﬂy ash-portlandcement.Cem Concr Res1984;14(4):505–11.[21]Sybert F,Wiens U,Eﬀect ofﬂy ashﬁneness on hydration charac-teristics and strength development.In:International conference on blended cement in construction,University of Sheﬃeld,UK,1991.152–65.[22]Harris HA,Thompson JL,Murphy TE.Factor aﬀecting the reactivityofﬂy ash from western coals.Cem Concr Aggr1987;9:34–7. [23]Berry EE,Hemmings RT,Zhang MH,Cornelious BJ,Golden DM.Hydration in high-volumeﬂy ash binders.ACI Mater J 1994;91:382–9.[24]Butler W.B,Mearing M.A,Fly ash beneﬁciation and utilization intheory and in practice.In:Symposium proceedings,Fly ash and coal conversion by-product:characterization,utilization and disposal II, Material Research Society,vol:65,1986.p.11–7.[25]Xu A,Sarker SL.Microstructure development in high-volumeﬂy ashcement system.ASCE J Mater Civ Eng1994;6:117–36.[26]Xu A,Sarker SL,Nilsson LO.Eﬀect ofﬂy ash on the microstructureof cement mortar.Mater.Struct.1993;26:414–24.[27]Lam L,Wong YL,Poon CS.Degree of hydration and gel/space ratioof high-volumeﬂy ash/cement systems.Cem Concr Res2000;30: 747–56.[28]Zhang MH.Microstructure crack propagation and mechanicalproperties of cement pastes containing high volume ofﬂy ashes.Cem Concr Res1995;25:1165–78.P.Chindaprasirt et al./Construction and Building Materials21(2007)1534–15411541。

CFA一级每日一练(含详细解析)103

CFA一级每日一练（含详细解析）1031、Tamlorn Mager, CFA, is an analyst at Pyallup Portfolio Management. CFA Institute recently notified Mager that his CFA Institute membership was suspended for a year because he violated the CFA Code of Ethics. A hearing panel also came to the same conclusion. Mager subsequently notified CFA Institute he does not accept the sanction, or the hearing panel’s conclusion. Which of the following actions by Mager is most consistent with the CFA Institute Professional Conduct Program?【单选题】A.Presenting himself to the public as a CFA charterholderB.Providing evidence for his position to an outside arbitration paneling his CFA designation upon expiration of the suspension period正确答案:C答案解析:“Code of Ethics and Standards of Professional Conduct”, CFA InstituteC is correct because the Designated Officer may impose a summary suspension on a member or candidate, which may be rejected or accepted by the member or candidate. If the member or candidate does not accept the proposed sanction, the matter is referred to a hearing panel composed of DRC members and CFA Institute member volunteers affiliated with the DRC. In this case, the hearing panel also affirmed the suspension decision by the Designated Officer, and therefore, the member loses the right to use his designation for a one-year period. Upon expiration of the suspension period, the analyst would be able to use his CFA designation.2、The effective annualized cost (%) of a banker’s acceptance that has an all-inclusive annual rate of 5.25% for a one-month loan of $2,000,000 is closest to:【单选题】A.5.27.B.5.38.C.5.54.正确答案:A答案解析:“Working Capital Management,” Edgar A. Norton, Jr., CFA, Kenneth L. Parkinson, and Pamela Peterson Drake, CFA 2013 Modular Level I, Vol. 4, Reading 40, Section 8.4., Example 7[1664201704061-image/0539.jpg]3、If Investor A has a lower risk aversion coefficient than Investor B, on the capital allocation line, will Investor B’s optimal portfolio have a higher expected return?【单选题】A.Yes.B.No, since Investor B has a lower risk tolerance.C.No, since Investor B has a higher risk tolerance.正确答案:B答案解析:“Portfolio Risk and Return: Part I,” Vijay Singal, CFAB is correct. Investor B has a higher risk aversion coefficient, therefore a lower risk tolerance and a lower expected return on the capital allocation line.4、Dispersion is defined as the variability around the central tendency and can bedivided into absolute dispersion and relative dispersion.Which of the followingis NOT described as a measure of relative dispersion?【单选题】A.Range.B.Sharpe ratio.C.Coefficient of variation.正确答案:A答案解析:B项夏普比率和C项变化系数都是表达相对偏离程度，而A项间距是表达绝对偏离程度，即用最大值减去最小值。

基金行业的委托代理关系与基金经理的短视行为研究_韩燕

经济与金融管理
文将从理性解释的角度探讨基金经理的这些行为特征。
委托代理关系下基金经理的投资行为
以基金为代表的机构投资者因其专业性通常被认为是理性投资者。因而，监管机构希望在股票市场发生［21 ］这些机构投资者会采用反向投资策略，削平市场的波动，从而稳定市场。然而，这一希望似非理性波动时，乎落空了。很多市场评论者指出，基金等机构投资者从事正反馈交易并且存在羊群效应。如果基金等机构投这就意味着相当一批基金经理并不具有信息优势，因此他们也就没有能力去资者的投资行为存在羊群效应，发现非理性波动并稳定市场了。更进一步，如果基金经理从事正反馈交易，他们就很可能不是在修正错误定，，。，，价而是跟随市场追涨杀跌因此他们不仅不能稳定市场反而会扩大市场波动。关于基金等机构投资者能否稳定市场这一问题很早就引起了学术界的关注。早期研究主要论证基金等机构投资者的正反馈交易和羊群效应是否以及为何存在。稍晚些研究也谈论了基金经理在委托代理关系下如何改变投资组合的风险特征。 1、正反馈交易与羊群效应的实证证据从计量经济学的角度看，羊群效应会导致基金经理在数据上表现为在从事正反馈交易。这是因为，羊群效应下的基金经理互相模仿，被一部分基金经理买入的股票，会被更多的基金经理买入。在这一自我强化的过程中，股价不断被推高，基金也不断买入股票，从而在计量经济学上表现为正反馈或动量交易多学者都把羊群效应和正反馈交易放在一起检验。
①机构投资者通常包含：
［6 ］
共同基金（ Mutual Funds，我国常简称为基金）、养老基金（ Pension Funds，我国主要为社保基金）、对冲基
保险公司、其他金融机构的自营投资和代理投资部门等。在学术文献中，针对美国机构投资者的研究通常涵盖所管理的金、资产规模在 100 万美元以上的机构投资者，而针对我国机构投资者的研究通常仅涵盖基金。这一研究对象上的差异主要源于数据可获得性。我国证券监督管理委员会（以下简称证监会）仅要求基金定期披露其信息，对其他机构投资者并无此类要求。美国证券交易委员会（ Securities and Exchange Commission，SEC）则要求所有机构投资者定期披露其持股数据。不过，据《中国证券业发展报告（ 2013 ）》，中国证券业协会发布的共同基金所持有的资产市值占所有机构投资者所持市值的 50. 16% 。因此，以往文献用我国的基金指代所有机构投资者是有一定合理性的。

《知识型员工的激励研究国内外文献综述6200字》

知识型员工的激励研究国内外文献综述目录知识型员工的激励研究国内外文献综述 (1)1员工激励机制 (1)2新生代知识型员工激励机制 (2)3知识型员工激励机制 (3)4新生代知识型员工激励机制 (4)5研究评述 (4)参考文献 (5)1员工激励机制激励制度对企业进行人力资源管理可以起到积极的促进作用。

就当前来讲，国外关于对激励理论研究时间相对于我国还是比较早的，利用对激励制度的建立健全，对于企业发展尤为重要。

目前在研究进展上，主要有三种较为成熟的激励理论有三种：第一种，是基于内容的激励理论。

Adhiatma（2021）认为这一理论是以激励为重点，主要包括奥德弗的ERG理论、赫兹伯格的双因素理论和麦克莱兰的成就需要激励理论；第二种，是基于过程的动机理论。

Leta（2020）指出，该研究方向侧重于从动机到行动的心理过程。

通过找出一些在行为中起决定性作用的关键因素，并找出它们之间的关系，从而预测和控制人类的行为；第三种，是行为矫正的动机理论。

Kuriakose（2019）认为该重点在于动机的目的，主要包括斯金纳的强化理论和韦纳的归因理论。

本次对其综述如下：在基于内容的激励理论方面，Ressi（2020）在货币激励内容方面认为，在激励机制中，自律和尊重社会影响的动机是不同的。

根据销售比率目标收集的绩效数据，可以替换货币激励和认可，并且提供的反馈相对独立。

因此该文得出，货币激励和认可之间存在负面互动。

它们是有形利益和社会尊重动机之间的分界线[1]。

张占武（2013）对某大型制造企业的员工以问卷调查形式得到结果显示，激励企业研发型人才主要使用的方式为：为其提供工作中的人际关系（8%）、工作的自由（8%）、工作中所获的成就（19%）、物质的奖励（20%）、个人成长空间45%[2]。

赵曼（2015）依据我国报业建立了激励制度，认为要想促进企业发展，一定要讲明薪酬与绩效之间的关系，合理安排员工岗位，并同时注意行为方式按照个人习性进行[3]。

Lesson 10

sway 指" 有伸缩性的物体受压后又恢复原位地摆动", 如: Branches sways gently in the wind. 树枝在风中微微摇动。 Rock是指温柔而有节奏感的摇动或猛烈的摇摆或倾斜 The business is on the rocks rock a baby (in)to sleep People used to say:The hand that rocks the cradle rules the world."过去人们常说,掌握摇篮的手统治世界。" Vibrate通常暗指快速的周期性摇摆；常常表示颤抖、搏动或微颤 The house vibrates when a train passes. Fluctuate最常用于喻指比较稳定的交替变化 The price of vegetables and fruits fluctuates according to the season. 蔬菜和水果的价格随季节而波动。 Undulate暗指波浪般平缓的运动
The ripe wheat undulated in the breeze like the incoming tide. 成熟的小麦象潮水般随风起伏。 Waver表示不稳定、不确定的运动 His resolve began to waver. 他的决心开始动摇了 2. A buzz ran through the …that sweltering July day in 1925: 1) buzz: the vibrating sound of a bee; here it refers to the sound of many people whispering or talking excitedly in low tones .嗡嗡声 v.作嗡嗡声 2) ran through the crowd : spread among the people who had come to watch the trial 3) as I took my place in the packed court : as I went to my seat in the court which was crowded with people 4) sweltering : oppressively hot and humid ; very hot, causing unpleasantness 闷热, 被暑气所苦, 汗流夹背

CJAS2013年第一卷第一期

Launching editorialFollowing the adoption of economic reform and open door policies over the last two decades,China ’s economy is now signi ﬁcantly integrated with international economies.Concurrently,Chinese accounting/auditing standards have made substantial strides towards convergence with International Financial Reporting Standards as well as Interna-tional Standards of Auditing.However,China ’s economy is still in a transitional phase with strong remnants of previous central planning regimes.Consequently,state owner-ship still has a strong presence in many sectors and enterprises and the government plays a signi ﬁcant role in business affairs,accounting and ﬁnance regulation,and enforcement.With the strong trend towards economic globalisation and accounting convergence,accounting and ﬁnance research in China can and should no longer be undertaken in isolation.At the same time,the transitional nature of China ’s economy offers numerous opportunities for identifying unique accounting and ﬁnance issues and solutions.To promote and support signi ﬁcant scholarship in this environment,we are pleased to launch The China Journal of Accounting Studies (CJAS)as a forum for knowledge exchange between and among Chinese and international academics,research students,policy makers and others interested in accounting and ﬁnance research and develop-ments in China and elsewhere.CJAS is the of ﬁcial international research journal of the Accounting Society of China.The Society was established in 1980and has been the largest accounting associ-ation in China,with over 2400individual members and over 250institutional members.Even with strict admission criteria,the numbers of both individual and institutional members continue to increase from year to year.As an association journal,CJAS will adhere to a principle of openness and inclusive-ness.This means that it welcomes high-quality papers in ﬁnancial accounting,manage-ment accounting,auditing,corporate ﬁnance,corporate governance,public sector accounting,social and environmental accounting,accounting education,accounting his-tory,accounting information systems,and related areas.The Journal will embrace a wide range of theoretical paradigms based on economics,sociology,psychology and other related sciences and social sciences and research methodologies (e.g.analytical,archival,experimental,survey and qualitative case methods).In addition,it will publish original papers on Chinese as well as non-Chinese accounting and ﬁnance theories,methods and issues.In particular,the Journal welcomes submissions that investigate Chinese and inter-national issues in comparative terms,whether comparing China with advanced economies or with other emerging and transitional economies.It expects such comparative studies to offer opportunities for identifying unique accounting and ﬁnance issues and solutions in individual countries,and also to provide settings for testing established theories and para-digms as well as developing new ones.It welcomes submissions in English or Chinese and will evaluate them on their origi-nality,rigor,relevance and quality of exposition.The EditorsV ol.1,No.1,1,/10.1080/21697221.2013.781768Ó2013Accounting Society of China D o w n l o a d e d b y [124.207.132.50] a t 19:00 04 J u n e 2013COMMENTARYGlobal comparability in ﬁnancial reporting:What,why,how,and when?Mary E.Barth*Graduate School of Business,Stanford University,Stanford,CA 94305,USAThe Conceptual Framework identi ﬁes comparability as a qualitative characteristic ofuseful ﬁnancial reporting information.This paper explains what comparability is,whycomparability is desirable,how comparability is achieved,and when we mightachieve it.In particular,comparability is the qualitative characteristic that enablesusers to identify and understand similarities in,and differences among,items;compa-rability aides investors,lenders and other creditors in making informed capital alloca-tion decisions;and achieving comparability depends on ﬁrms applying a common setof ﬁnancial reporting standards and on requirements in the standards,especially mea-surement requirements.The paper discusses research showing that greater compara-bility can lower costs of comparing investment opportunities and improving ﬁnancialreporting information quality.When comparability might be achieved is uncertain,although much progress has been made recently.Keywords:Comparability;global ﬁnancial reporting;International Financial Report-ing Standards;Conceptual FrameworkThe Conceptual Framework of the International Accounting Standards Board (IASB,2010)speci ﬁes comparability as one of the qualitative characteristics of ﬁnancial report-ing information,which enable that information to achieve the objective of ﬁnancial reporting.That objective is to provide investors,lenders and other creditors with infor-mation that helps them in making their capital allocation decisions.Because capital is a scare resource,comparability is a crucial characteristic of ﬁnancial reporting informa-tion.If investors,lenders and other creditors cannot make informed comparisons of alternative investment opportunities,their capital allocation decisions will be subopti-mal.In fact,some believe that enabling investors to compare investment opportunitiesis the main reason we need ﬁnancial accounting standards to prescribe the contents of ﬁnancial reports.Without such standards,ﬁrms could portray and provide information about their ﬁnancial position and performance in any way they choose.Given that ﬁnancial reporting does not derive from a law of nature,there are innumerable ways ﬁrms could do that,and comparability would be lost.Thus,comparability is crucial to high quality ﬁnancial reporting.This discussion seeks to explain what comparability is,why comparability creates bene ﬁts for investors and the ﬁrms in which they invest,how comparability can be achieved,and when we might achieve it.*Email:mbarth@Paper accepted by Jason Xiao.V ol.1,No.1,2–12,/10.1080/21697221.2013.781765Ó2013Accounting Society of ChinaD o w n l o a d e d b y [124.207.132.50] a t 19:15 04 J u n e 2013What is comparability?Although the word ‘comparability ’has a meaning in the English language,ﬁnancial accounting standard setters have a precise de ﬁnition in mind.The Conceptual Frame-work explains that comparability is the qualitative characteristic of ﬁnancial reporting information that enables users to identify and understand similarities in,and differences among,items.That is,comparability results in like things looking alike and different things looking different.The Conceptual Framework goes on to explain that compara-bility makes ﬁnancial reporting information useful because the information can be com-pared to similar information about other entities or about the same entity at a different parability does not relate to a single item;comparability requires at least two items that are being compared.To avoid misunderstanding,it is important to clarify what comparability is parability is not consistency.Consistency refers to the use of the same accounting methods or principles by a ﬁrm for the same items over parability is a goal of consistency and,thus,consistency helps achieve comparability.In itself,however,consistency does not ensure parability also is not uniformity.This is a source of confusion for parability results in like things looking alike and different things looking different.Uniformity requires treating all things in the same way.As a result,uniformity can make unlike things look alike,which impairs,not enhances,comparability.For example,consider an accounting rule specifying that all buildings be depreciated on a straight-line basis using a 30-year useful life and assuming a 10%residual value.Thus,the depreciation method for all buildings would be the same.What if some buildings last 20years and others last 200years?What if some buildings have a 5%residual value and others have a 25%residual value?What if some buildings deteriorate more rapidly at ﬁrst and others deteriorate more rapidly nearer the end of their lives?Unless all buildings have a 30-year useful life,a 10%residual value,and economic bene ﬁts that are consumed in a straight-line pattern,using the same depreciation method achieves uniformity,but not comparability.It makes all buildings look alike,when in fact they are different.That is not compara-bility.The Conceptual Framework also explains that some degree of comparability can be achieved by faithful representation,which is one of the fundamental qualitative charac-teristics of ﬁnancial reporting information.That is,if ﬁnancial statements faithfully rep-resent an item –e.g.,an asset or a liability –then comparability should follow.This is because a faithful representation would re ﬂect the characteristics of the item.In the building example,if the residual value of a particular building is 25%,not 10%,then depreciating the building assuming a 10%residual value would not result in a faithful representation of the building.Comparability:why?Why is comparability so crucial to ﬁnancial reporting?The primary reason –as with all qualitative characteristics of ﬁnancial reporting information –is to help meet the objec-tive of ﬁnancial reporting.That objective is to provide ﬁnancial information about the entity that is useful to existing and potential investors,lenders and other creditors in making decisions about providing resources to the entity.The Conceptual Framework explains that decisions to buy,sell,or hold equity and debt instruments require alloca-tion of capital,and ﬁnancial reporting is aimed at those who cannot demand the infor-mation they need to make those capital allocation decisions.Thus,comparability in China Journal of Accounting Studies 3D o w n l o a d e d b y [124.207.132.50] a t 19:15 04 J u n e 2013ﬁnancial reporting across entities and over time is crucial to enabling investors,lenders and other creditors to make more informed capital allocation decisions.Comparability:how?Having established the importance of comparability,the next question is how can it be achieved?This,of course,is not a simple task.Global standardsWhen many people think about comparability in ﬁnancial reporting,they think about the increasing use of International Financial Reporting Standards (IFRS).This is,in part,because the stated vision for IFRS is:…one single set of high quality global standards ed on the global capital markets.Many equate use of the same set of standards with achieving comparability.This vision for IFRS is based on the belief that use of global standards will improve the functioning of global capital markets.This should occur by increasing comparability and the quality of information,and by decreasing the costs of preparing ﬁnancial reports,particularly for multinational ﬁrms,and information rmation risk is the risk that investors perceive when they know that they do not fully understand the information they are given,which would be the case if they are not ‘ﬂuent ’in the accounting standards on which a ﬁrm ’s ﬁnancial statements are based.Decreasing information risk should decrease the cost of capital.It is dif ﬁcult to imagine how comparability can be achieved without the use of glo-bal ﬁnancial reporting standards.However,use of global standards is only a necessary step –not a suf ﬁcient step –to achieving comparability because,for example,the stan-dards need to be rigorously applied and enforced.Ensuring any set of ﬁnancial report-ing standards achieves its potential ultimately depends on ﬁrms applying the standards as written,auditors auditing the resulting ﬁnancial statements to ensure compliance with the standards,and regulators enforcing the standards.Requirements in standards Although a focus over the last decade or so has been on the widespread adoption ofIFRS as a means of achieving comparability,even strict adherence to a single set of standards does not ensure comparability.The requirements in the standards also affect comparability and,thus,should not be overlooked.Let me explain how and why.The Conceptual Framework considers ﬁnancial statement elements,e.g.,assets,lia-bilities,income,and expense,item by item.Examples of ﬁnancial statement elements are accounts receivable,inventory,and long-term debt.The aim of focusing on ﬁnancial statement elements item by item is to provide investors with comparable information about the entity ’s assets and claims against those assets.Pro ﬁt or loss is the change in the assets and claims that do not arise from other assets,liabilities,or transactions with equity holders in their capacity as equity holders.The assumption underlying this focus is that comparability results from portraying ﬁnancial statement elements in the same way,for example by recognizing the same (sub)set of assets and liabilities and measur-ing them in the same way.However,does recognizing the same (sub)set of assets and liabilities achieve compa-rability?What if different assets and liabilities are important for some ﬁrms versus oth-4BarthD o w n l o a d e d b y [124.207.132.50] a t 19:15 04 J u n e 2013ers?For example,what about intellectual property assets of knowledge-based ﬁrms;property,plant,and equipment for durable manufacturers;and insurance liabilities for insurers?Do we achieve comparability if some assets –e.g.,intangibles –or particular types of claims –e.g.,claims with uncertain outcomes –are omitted?Do we achieve comparability if we omit intellectual property assets for all ﬁrms?Unrecognized assets and liabilities also have direct consequences for comparability of pro ﬁt or loss because pro ﬁt or loss depends on changes in recognized asset and liability amounts.Thus,if an asset is omitted,by construction the change in its recognized amount is zero and,as a result,it has no effect on pro ﬁt or loss.If we omit intellectual property assets for all ﬁrms,do the ﬁnancial statements of a knowledge-based ﬁrm and a durable manufacturer re ﬂect their similarities and differences in a way that enables investors,lenders and other creditors to make informed capital allocation decisions?I cannot see how they can.MeasurementMeasurement also plays a crucial role in comparability that is often overlooked.Because ﬁnancial reporting standards focus on ﬁnancial statement elements item by item,one is lulled into thinking that measuring the same asset in the same way helps achieve comparability.But,does it?What if the measure is modi ﬁed historical cost?1Although the method is the same,the resulting amounts likely differ.For example,the same asset purchased at different times will likely have a different measure.More dif-ferences can emerge over the life of the asset,e.g.,if the asset is impaired or is part of a fair value hedge and,thus,its carrying amount is adjusted for the change in fair value attributable to the risk identi ﬁed in the fair value hedge.How can modi ﬁed historical cost achieve comparability?What if the measure is fair value?IFRS 13Fair Value Measurement de ﬁnes fair value as the price that would be obtained to sell an asset or transfer a liability between market participants at the measurement date.Fair value has the potential to achieve com-parability because one would expect economic differences and similarities to be re ﬂected in value.Thus,using fair values makes like things look alike and different things look different.However,a concern about using fair value is the potential effects of discretion in estimating the fair values.Although some assets and liabilities have readily determin-able market values,others do not,which means that their fair values must be estimated by managers.Whenever estimates are used in ﬁnancial reporting –which is almost everywhere –there is concern that managers will use their discretion opportunistically to affect the estimates.There is a vast academic literature that ﬁnds evidence of manag-ers ’opportunistic exercise of discretion relating to many accounting amounts,regardless of whether they are based on modi ﬁed historical cost or on fair value.What if the measure were something else?Perhaps another measure exists that over-comes the undesirable features of both modi ﬁed historical cost and fair value and pos-sesses desirable features.Unfortunately,standard setters have yet to identify such an alternative measure.As an example to illustrate the effects on comparability of using cost or fair value to measure all assets,consider three entities:Entity A,Entity B,and Entity C.Entities A,B,and C each owns one share of common stock in Entity Z.The acquisition cost is 20for Entity A,40for Entity B,and 60for Entity C,and the current fair value of a share of common stock in Entity Z is 45.Are the ﬁnancial statements of Entities A,B,and C comparable if each measures its investment at cost?The answer is ‘no ’because the three cost amounts –20,40,and 60–make the asset look different when it is the same.Thus,China Journal of Accounting Studies 5D o w n l o a d e d b y [124.207.132.50] a t 19:15 04 J u n e 2013cost makes like things look different,thereby failing to achieve comparability.Are the ﬁnancial statements of Entities A,B,and C comparable if each measures its investment at fair value?The answer is ‘yes ’because all three entities would measure the asset at 45,which means that the same asset held by different entities looks the same.That achieves comparability.However,this conclusion is only clear because the fair value was speci ﬁed in this example.To the extent that Entities A,B,and C need to estimate the fair value,they might estimate different amounts.In such a case,whether cost or fair value provides more comparability depends on whether the range of fair value estimates is smaller than 40,i.e.,60minus 20.That is,it depends on whether fair value results in making the same asset held by the three entities look more alike than cost.Some might argue that comparability is best achieved by reporting both amounts,for example if each entity measures the investment at cost and discloses the fair value.However,the Conceptual Framework is clear that disclosure is not a substitute for rec-ognition and the limited academic research that exists on recognition versus disclosure tends to support that view.What about measuring different assets of the entity in different ways?Can this achieve comparability?For example,presently we measure many ﬁnancial assets at fair value and property,plant,and equipment at modi ﬁed historical cost.We impair accounts receivable for incurred credit losses;property,plant,and equipment to recoverable amount;and inventory to lower of cost or fair value less costs to sell.We measure most long-term debt at amortized cost and derivative liabilities at fair value.There are many measurement methods used in ﬁnancial reporting and most often the different measures apply to differ-ent assets.The question is whether this approach can achieve comparability.As an example to illustrate this issue,consider the assets of Entity A and Entity B.A B Cash 500500Accounts receivable 10001000Property,plant,and equipment 15001500Total assets 30003000The reported assets of these two entities –3000–make the assets look the same,and it appears that each entity ’s accounts receivable represents one-third of its assets and prop-erty,plant,and equipment represents one-half of its assets.If this reporting achieves comparability,then the two entities should have the same assets and these proportions should re ﬂect the economics of the assets each entity holds.What if Entity A measures accounts receivable at fair value and property,plant,and equipment at modi ﬁed historical cost,with all amounts in US dollars?Assume Entity A ’s property,plant,and equipment was purchased at various times over the last ten years.What if Entity B measures all assets at fair value and cash is stated in US dol-lars,accounts receivable is stated in euros,and property,plant,and equipment is stated in Swiss francs?Are these two entities comparable?Do the proportions of total assets each reports for the three assets re ﬂect the economics of the assets?The answer is ‘no ’.How does a ﬁnancial statement user compare Entity A ’s property,plant,and equip-ment with Entity B ’s?In addition,what do the 3000in total assets for Entities A and B represent?Are these amounts comparable to each other?Are they comparable to any-thing?Each 3000is the sum of three numbers derived on different bases.Like the sum of apples and oranges,its meaning is unclear.Many might react to this example by say-6BarthD o w n l o a d e d b y [124.207.132.50] a t 19:15 04 J u n e 2013ing that ‘we would never account for Entity B ’s assets using different currencies and that would be true ’.However,the distinction between using different currencies for Entity B ’s assets and using different measurements for different assets for Entity A is not clear.Why do we recoil at one and accept the other without question?One likely reason is that we are not accustomed to one but are accustomed to the other.Is there any other reason?Can we achieve comparability if we measure the same asset in different ways –either for the same entity or different entities?For example,presently we treat comput-ers as inventory for some entities (e.g.,Apple)and as equipment for others (e.g.,Gen-eral Electric).We treat warranty obligations relating to sales of goods by retailers differently from insurance contracts issued by insurance companies even though they are both insurance contracts.We treat real estate as investment property for some enti-ties (and measure it at fair value)and as property,plant,and equipment for others (and measure it at amortized cost).We treat the gain or loss on an item designated as hedged in a fair value hedge differently from the same gain or loss on an item that is not so designated (i.e.,in a designated fair value hedge,we adjust the carrying amount of the hedged item for its change in value attributable to the hedged risk).In addition,we per-mit optional asset revaluation,application of fair value,and hedge accounting itself.All of these differences result in differences in amounts in the ﬁnancial statements for what seem to be the same assets and liabilities.Consider an example.Assume Entity A and Entity B each buys a piece of construc-tion equipment for 200.Entity A classi ﬁes the equipment as inventory and Entity B classi ﬁes it as property,plant,and equipment.Six months later,both entities still own the equipment;Entity A holds it in inventory and B has depreciated it because it is available for use,but Entity B has not used it.Entities A and B both dispose of the equipment for a gain.In its income statement,Entity A displays revenue and expense,which net to the amount of the gain,and Entity B displays the gain net.The asset –a piece of construction equipment –is the same for both entities.Yet,the asset is mea-sured at different amounts and the gain on disposal of the asset is presented differently.The question is whether the ﬁnancial statements of Entities A and B are comparable.Consider another example,which is often used to illustrate this issue.Assume that Bank A and Bank B each buys US Treasury securities at a cost of US$1million.At the reporting date,the fair value of the securities is US$1.2million.Bank A classi ﬁes the securities as trading (or fair value through pro ﬁt or loss)and recognizes US$1.2million in assets and a gain of US$0.2million.Bank B classi ﬁes the securities as held to maturity (or amortized cost)and recognizes US$1.0million in assets and no gain or loss.In both cases,the bank owns the same asset –US Treasury securities –purchased for the same amount –US$1million –and now worth the same amount –US$1.2million.Yet the ﬁnancial statements of Bank A and Bank B are quite different.Does this ﬁnancial report-ing make like things look alike?That is,are the ﬁnancial statements of Entities A and B comparable?The answer is ‘no ’.Does ‘use ’of an asset affect its economics?A question relating to comparability to which we do not have a good answer is whether two assets that seem the same (e.g.,computers)are economically the same if they are used differently (e.g.,as inventory or property,plant,and equipment).If the use of an asset affects its economics,we need to identify how the economics are affected so that we can determine whether and how the differences in economics should be re ﬂected China Journal of Accounting Studies 7D o w n l o a d e d b y [124.207.132.50] a t 19:15 04 J u n e 2013when accounting for the asset.Accountants have been treating seemingly similar assets differently for a long time –the inventory versus property,plant,and equipment exam-ple is not new.However,we have never articulated why.Without knowing why differ-ent uses of an asset affect the economics of the asset that should be re ﬂected in the accounting,it is not possible to determine when and how to re ﬂect such differences.In addition,we need to know whether the notion of different uses of assets applies to all assets.In particular,does it apply to ﬁnancial assets and liabilities?IFRS 13concludes ‘no ’and explains why.But more thought needs to be devoted to this notion as it applies to non-ﬁnancial assets.Recently,the notion that the use of assets should affect the accounting for the assets has been characterized as re ﬂecting an entity ’s ‘business model ’.Thus,the question can be rephrased as whether different ‘use ’of an asset depends on the entity ’s ‘business model ’.Unfortunately,the Conceptual Framework has no concepts about the role of business model in ﬁnancial reporting.In addition,there is no de ﬁnition of a business model and,thus,it is unclear what the term means.Some question whether an entity ’s business model differs in any substantive way from management intent (Leisenring,Lins-meier,Schipper,&Trott,2012).Is the business model something that management is doing,plans to do,or only hopes to do?Is an entity ’s business model veri ﬁable?Is it auditable?The answers to these questions are not obvious,which only adds to the lack of clarity about why and how a business model or intent should affect ﬁnancial reporting.What does research say?Academic research provides evidence that global ﬁnancial reporting with greater compa-rability can be bene ﬁcial to investors,by lowering costs of comparing cross-border investment opportunities and,for some countries and ﬁrms,by improving the quality of their ﬁnancial reporting information.Research also shows that comparability can be ben-e ﬁcial to ﬁrms by increasing cross-border investment and by lowering cost of capital,presumably from reducing information risk and,for some,by increasing ﬁnancial report-ing quality.However,research also provides evidence that these potential bene ﬁts are tempered by cross-country differences in implementation,incentives,and enforcement.One example of a study in this literature is ‘Market Reaction to the Adoption of IFRS in Europe ’(Armstrong,Barth,Jagolinzer,&Riedl,2010).The questions motivat-ing this study are:(1)did investors perceive net bene ﬁts to adoption of IFRS in Eur-ope?and (2)if there were net bene ﬁts,are the net bene ﬁts associated with increased comparability or increased quality of ﬁnancial reporting information?As with any sin-gle research study,this study cannot directly answer these questions.However,these motivating questions lead to two research questions that the study can answer.The ﬁrst is:did the European stock market react positively (negatively)to regulatory events that increased (decreased)the likelihood of IFRS adoption in Europe?An af ﬁrmative answer to this question indicates that investors perceived net bene ﬁts to IFRS adoption in Eur-ope.The second is:were there differences across ﬁrms depending on their pre-adoption information environment?Identifying differences across ﬁrms in the market reaction to the regulatory events provides insights into what ﬁrm characteristics are associated with the perceived bene ﬁts of IFRS adoption.The study focuses on 16regulatory events,which begin with the 2002European Par-liament resolution requiring all listed ﬁrms in the European Union to apply IFRS by 2005.The events end with the 2005European Commission endorsement of the revised fair value option.The events and predicted signs of the effect on the likelihood of IFRS adop-8BarthD o w n l o a d e d b y [124.207.132.50] a t 19:15 04 J u n e 2013。

ACCA P5 Summary

1Introduction to strategic management accounting1.1I ntroduction to planning, control and decision making☞Strategic planning is the process of deciding on objectives of the organization, on changes in these objectives, on the resource to attain these objectives, and on the policies that are to govern the acquisition, use and disposition of these resources.☞Characteristics of strategic information⏹Long term and wide scope⏹Generally formulated in writing⏹Widely circulated广泛流传⏹Doesn’t trigger direct action, but series of lesser plans⏹Includes selection of products, purchase of non-current assets, required levels ofcompany profit☞Management control: the process by which management ensure that resources are obtained and used effectively and efficiently in the accomplishment of the organisation’s objectives. It is sometimes called tactics ad tactical planning.☞Characteristics of management accounting information⏹Short-term and non-strategic⏹Management control planning activities include preparing annual sales budget⏹Management control activities include ensuring budget targets are reached⏹Carried out in a series of routine and regular planning and comparison procedures⏹Management control information covers the whole organisation, is routinely collected,is often quantitative and commonly expressed in money terms (cash flow forecasts, variance analysis reports, staffing levels⏹Source of information likely to be endogenous内生的☞Characteristics of operational control⏹Short-term and non-strategic⏹Occurs in all aspects of an organisations activities and need for day to dayimplementation of plans⏹Often carried out at short notice⏹Information likely to have an endogenous source, to be detailed transaction data,quantitative and expressed in terms of units/hours⏹Includes customer orders and cash receipts.1.2Management accounting information for strategic planning and control☞Strategic management accounting is a form of management accounting in which emphasis is placed on information about factors which are external to the organisation, as well as non-financial and internally-generated information.⏹External orientation: competitive advantage is relative; customer determination⏹Future orientation: forward- and outward looking; concern with values.⏹Goal congruence: translates the consequences of different strategies into a commonaccounting language for comparison; relates business operations to financial performance.1.3Planning and control at strategic and operational levels☞Linking strategy and operations, if not: unrealistic plans, inconsistent goals, poor communication, inadequate performance measurement.1.3.1Strategic control systems☞Formal systems of strategic control:⏹strategy review;⏹identify milestones of performance( outline critical success factors, short-term stepstowards long-term goals, enables managers to monitor actions)⏹Set target achievement levels (targets must be reasonably precise, suggest strategiesand tactics, relative to competition)⏹Formal monitoring of the strategic process⏹Reward.☞Desired features of strategic performance measures⏹Focus on what matters in the long term⏹Identify and communicate drivers of success⏹Support organisational learning⏹Provide a basis for reward⏹Measurable; meaningful; acceptable;⏹Described by strategy and relevant to it⏹Consistently measured⏹Re-evaluated regularly1.4Benchmarking1.4.1Types of benchmarking☞Internal benchmarking: easy; no innovative or best-practice.☞Industry benchmarking:⏹Competitor benchmarking: difficult to obtain information⏹Non-competitor benchmarking: motivate☞Functional benchmarking: find new, innovative ways to create competitive advantage1.4.2Stages of benchmarking☞Set objectives and determine the area to benchmark☞Establish key performance measures.☞Select organizations to study☞Measure own and others performance☞Compare performance☞Design and implement improvement prgoramme☞Monitor improvements1.4.3Reasons for benchmarking☞Assess current strategic position☞Assess generic competitive strategy☞Spur to innovation☞Setting objectives and targets☞Cross comparisons☞Implementing change☞Identifies the process to improve☞Helps with cost reduction, or identifying areas where improvement is required☞Improves the effectiveness of operations☞Delivers services to a defined standard☞Provide early warning of competitive disadvantage1.4.4Disadvantages of benchmarking☞Implies there is one best way of doing business☞Yesterday’s solution to tomorrow’s problem☞Catching-up exercise rather than the development of anything distinctive☞Depends on accurate information about comparator companies☞Potential negative side effects of ‘what gets measured gets done’.2Performance management and control of the organization2.1Strengths and weaknesses of alternative budget models2.1.1Incremental budgeting☞Is the traditional approach to setting a budget and involves basing next year’s budget on the current year’s results plus an extra amount for estimated growth of inflation next year. ☞Strengths: easy to prepare; can be flexed to actual levels to provide more meaningful control information☞Weaknesses: does not take account of alternative options; does not look for ways of improving performance; only works if current operations are as effective, efficient and economical as they can be; encourage slack in the budget setting process.2.1.2Zero based budgeting☞Preparing a budget for each cost centre from scratch.☞Strengths:⏹Provides a budgeting and planning tool for management that responds to changes inthe business environment.⏹Requires the organization to look very closely at its cost behavior patterns, andimproves understanding of cost-behaviour patterns.⏹Should help identify inefficient or obsolete processes, and thereby also help reducecosts.⏹Results in a more efficient allocation of resources⏹Be particularly useful in not-for-profit organizations which have a focus on achievingvalue for money.☞Weaknesses:⏹Requires a lot of management time and effort⏹Requires training in the use of ZBB techniques so that these are applied properly⏹Questioning current practices and processes can be seen as threatening2.1.3Rolling budgets☞Continuously updated by adding a further period when the earliest period has expired.☞Strengths:⏹Reduce the uncertainty of budgeting for business operating in an unstableenvironment. It is easier to predict what will happen in the short-term.⏹Most suitable form of budgeting for organizations in uncertain environments, wherefuture activity levels, costs or revenues cannot be accurately foreseen.⏹Planning and control is based on a more recent plan which is likely to be morerealistic an more relevant than a fixed annual budget drawn up several months ago.⏹The process of updating the budget means that managers identify current changes( and so can respond to these changes more quickly)⏹More realistic targets provide a better basis on which to appraise managers’performance⏹Realistic budgets are likely to have a better motivational effect on managers.☞Weaknesses:⏹Require time, effort and money to prepare and keep updating. If managers spend toolong preparing/revising budgets, they will have less time to control and manage actual results⏹Managers may not see the value in the continuous updating of budgets⏹May be demotivating if targets are constantly changing⏹It may not be necessary to update budgets so regularly in a stable operatingenvironment.2.1.4Flexible budgets☞Recognizing the potential uncertainty, budgets designed to adjust costs levels according to changes in the actual levels of activity and output.☞Strengths:⏹Finding out well in advance the costs of idle time and so on if the output falls belowbudget.⏹Being able to plan for the alternative use of spare capacity if output falls short ofbudget☞Weaknesses:⏹As many errors in modern industry are fixed costs, the value of flexible budgets as aplanning tool are limited.⏹Where there is a high degree of stability, the administrative effort in flexiblebudgeting produces little extra benefit. Fixed budgets can be perfectly adequate in these circumstances.2.1.5Activity based budgeting☞Involves defining the activities that underlie the financial figures in each function and usingthe level of activity to decide how much resources should be allocated, how well it is being managed and to explain variance from budget.☞Strengths:⏹Ensures that the organisation’s overall strategy and any changes to that strategy willbe taken into account.⏹Identifies critical success factors which are activities that a business must perform wellif it is to succeed⏹Recognizes that activities drive costs; so encourages a focus on controlling andmanaging cost drivers rather than just the costs⏹Concentrate on the whole activities so that there is more likelihood of getting it rightfirst time.☞Weaknesses:⏹Requires time and effort to prepare so suited to a more complex organization withmultiple cost drivers.⏹May be difficult to identify clear individual responsibilities for activities⏹Only suitable for organization which have adopted an activity-based costing system⏹ABBs are not suitable for all organization, especially with significant proportions offixed overheads.2.1.6The future of budgeting☞Criticisms of traditional budgeting⏹Time consuming and costly⏹Major barrier to responsiveness, flexibility and change⏹Adds little value given the amount of management time required⏹Rarely strategically focused⏹Makes people feel undervalued⏹Reinforces department barriers rather than encouraging knowledge sharing⏹Based on unsupported assumptions and guesswork as opposed to sound,well-constructed performance data⏹Development and updated infrequently2.2Budgeting in not-for-profit organizations☞Special issues: the budget process inevitably has considerable influence on organizational processes, and represents the financial expression of policies resulting from politically motivated goals and objectives. The reality of life for many public sector managers is an subjected to(受---支配) growing competition.⏹Be prevented from borrowing funds⏹Prevent the transfer of funds from one budget head to another without compliancewith various rules and regulations⏹Plan one financial year.⏹Incremental budgeting and the bid system are widely used.2.3Evaluating the organisation’s move beyond budgeting2.3.1Conventional budgeting in a changing environment☞Weaknesses of traditional budgets:⏹Adds little value, requires far too much valuable management time⏹Too heavy a reliance on the ‘agreed’ budget has an adverse impact on managementbehavior, which can become dysfunctional(功能失调的) with regard to(关于) the objectives of the organization as a whole⏹The use of budgeting as a base for communicating corporate goals, is contrary to theoriginal purpose of budgeting as a financial control mechanism⏹Most budgets are not based on a rational, causal(因果关系的) model of resourceconsumption, but are often the result of protracted internal bargaining processes.⏹Conformance to budget is not seen as compatible with a drive towards continuousimprovement⏹Traditional budgeting processes have insufficient external focus.2.3.2The beyond budgeting model☞Rolling budgets focus management attention on current and likely future realities within the organizational context, it is seen as an attempt to keep ahead of change, or strictly speaking to be more in control of the response to the challenges facing the organization. ☞Benefits:⏹Creates and fosters a performance climate based on competitive success. Managerialfocus shifts from beating other managers for a slice(部分) of resources to beating the competition.⏹It motivates properly by giving them challenges, responsibilities and clear values asguidelines. Rewards are team-based⏹It empowers operational managers to act by removing resource constraints. Speedingup the response to environmental threats and enabling quick exploitation of new opportunities.⏹It devolves performance responsibilities to operational management who are closer tothe action.⏹It establishes customer-orientated teams that are accountable for profitable customeroutcomes.⏹Creates transparent and open information systems throughout the organization,provides fast, open and distributed information to facilitate control at all levels.3Business structure, IT development and other environmental and ethical issues3.1Business structure and information needs3.1.1Functional departmentation☞Information characteristics and needs: information flows vertically; functions tend to be isolated☞Implications for performance management⏹Structure is based on work specialism⏹Economies of scale⏹Does not reflect the actual business processes by which values is created⏹Hard to identify where profits and losses are made on individual products or inindividual markets⏹People do not have an understanding of how the whole business works⏹Problems of co-ordinating the work of different specialisms.3.1.2The divisional form☞Information characteristics and needs⏹Divisionalisation is the division of a business into autonomous regions⏹Communication between divisions and head office is restricted, formal and related toperformance standards⏹Headquarters management influence prices and therefore profitability when it setstransfer prices between divisions.⏹Divisionalisation is a function of organisation size, in numbers and in product-marketactivities.☞Implications for performance management⏹Divisional management should be free to use their authority to do what they think isright, but must be held accountable to head office⏹ A division must be large enough to support the quantity and quality of managementit needs⏹Each division must have a potential for growth in its own area of operations⏹There should be scope and challenge in the job for the management of the division☞Advantages:⏹Focuses the attention of subordinate(下级) management on business performanceand results⏹Management by objectives can be applied more easily⏹Gives more authority to junior managers, more senior positions⏹Tests junior managers in independent command early in their careers and at areasonably low level in the management hierarchy.⏹Provides an organisation structure which reduces the number of levels ofmanagement.☞Problems:⏹Partly insulated from shareholders and capital markets⏹The economic advantages it offers over independent organisations ‘reflectfundamental inefficiencies in capital markets’⏹The divisions are more bureaucratic than they would be as independent corporation⏹Headquarters management usurp divisional profits by management charges,cross-subsidies, unfair transfer pricing systems.⏹Sometime, it is impossible to identify completely independent products or markets⏹Divisionalisation is only possible at a fairly senior management level⏹Halfway house(中途地点)⏹Divisional performance is not directly assessed by the market⏹Conglomerate diversification3.1.3Network organisations☞Information characteristics and needs: achieve innovative response in a changingcircumstances; communication tends to be lateral(侧面的), information and advice are given rather than instructions(指令) and decisions.☞Virtual teams: share information and tasks; make joint decision; fulfil the collaborative function of a team)☞Implications for performance management⏹Staffing: shamrock organisation⏹Leasing of facilities such as IT, machinery and accommodation(住房)⏹Production itself might be outsourced⏹Interdependence of organisations☞Benefits: cost reduction; increased market penetration; experience curve effects.3.2Business process re-engineering3.2.1Business processes and the technological interdependence betweendepartments☞Pooled interdependence(联营式相互依赖): each department works independently to the others, subjects to achieve the overall goals☞Sequential interdependence(序列式相互依存): a sequence with a start and end point.Management effort is required to ensure than the transfer of resources between departments is smooth.☞Reciprocal interdependence(互惠式相互依存): a number of departments acquire inputs from and offer outputs to each other.3.2.2Key characteristics of organisations which have adopted BPR☞Work units change from functional departments to process teams, which replace the old functional structure☞Jobs change. Job enlargement and job enrichment☞People’s roles change. Make decisions relevant to the process☞Performance measures concentrate on results rather than activities.☞Organisation structures change from hierarchical to flat3.3Business integration3.3.1Mckinsey 7S model☞Hard elements of business behaviour⏹Structure: formal division of tasks; hierarchy of authority⏹Strategy: plans to outperform胜过its competitors.⏹Systems: technical systems of accounting, personnel, management information☞‘soft’ elements⏹Style: shared assumptions, ways of working, attitudes and beliefs⏹Shared values: guiding beliefs of people in the organisation as to why it exists⏹Staff: people⏹Skills: those things the organisation does well3.3.2Teamwork and empowerment☞Aspects of teams:⏹Work organisation: combine the skills of different individuals and avoid complexcommunication⏹Control: control the behaviour and performance of individuals, resolve conflict⏹Knowledge generation: generate ideas⏹Decision making: investigate new developments, evaluate new decisions☞Multi-disciplinary teams:⏹Increases workers‘ awareness of their overall objectives and targets⏹Aids co-ordination⏹Helps to generate solutions to problems, suggestions for improvements☞Changes to management accounting systems⏹Source of input information: sources of data, methods used to record data⏹Processing involved: cost/benefit calculation⏹Output required: level of detail and accuracy of output, timescales involved⏹Response required:⏹When the output is required:3.4Information needs of manufacturing and service businesses3.4.1Information needs of manufacturing businesses☞Cost behaviour:⏹Planning: standard costs, actual costs compared with⏹Decision making: estimates of future costs to assess the likely profitability of a product⏹Control: monitor total cost information☞Quality: the customer satisfaction is built into the manufacturing system and its outputs☞Time: production bottlenecks, delivery times, deadlines, machine speed☞Innovation: product development, speed to market, new process. Experience curve, economies of scale, technological improvements.☞Valuation:☞Strategic, tactical and operational information⏹Strategic: future demand estimates, new product development plans, competitoranalysis⏹Tactical: variance analysis, departmental accounts, inventory turnover⏹Operational: production reject rates, materials and labour used, inventory levels3.4.2Service businesses☞Characteristics distinguish from manufacturing:⏹Intangibility: no substance⏹Inseparability/simultaneity: created at the same time as they are consumed⏹Variability/heterogeneity异质性: problem of maintaining consistency in the standardof output⏹Perishability非持久性:⏹No transfer of ownership:☞Strategic, tactical and operational information⏹Strategic: forecast sales growth and market share, profitability, capital structure⏹Tactical: resource utilisation, customer satisfaction rating⏹Operational: staff timesheets, customer waiting time, individual customer feedback3.5Developing management accounting systems3.5.1Setting up a management accounting system☞The output required: identify the information needs of managers☞When the output is required:☞The sources of input information: the output required dictate the input made3.6Stakeholders’ goals and objectives3.6.1The stakeholder view☞Organisations are rarely controlled effectively by shareholders☞Large corporations can manipulate markets. Social responsibility☞Business receive a lot of government support☞Strategic decisions by businesses always have wider social consequences.3.6.2Stakeholder theory☞Strong stakeholder view: each stakeholder in the business has a legitimate claim on management attention. Management’s job is to balance stakeholder demands:⏹Managers who are accountable to everyone are accountable to none⏹Danger of the managers favour their own interests⏹Confuses a stakeholder’s interest in a firm with a person citizenship of a state⏹People have interest, but this does not give them rights.3.7Ethics and organisation3.7.1Short-term shareholder interest(laissez-faire自由主义stance)☞Accept a duty of obedience to the demands of the law, but would not undertake to comply with any less substantial rules of conduct.3.7.2Long-term shareholder interest (enlightened self-interest开明自利)☞The organisation’s corporate image may be enhanced by an assumption of wider responsibilities.☞The responsible exercise of corporate power may prevent a built-up of social and political pressure for legal regulation.3.7.3Multiple stakeholder obligations☞Accept the legitimacy of the expectations of stakeholders other than shareholders. It is important to take account of the views of stakeholders with interests relating to social and environmental matters.☞Shape of society: society is more important than financial and other stakeholder interests.3.7.4Ethical dilemmas☞Extortion: foreign officials have been known to threaten companies with the complete closure of their local operations unless suitable payments are made☞Bribery: payments for service to which a company is not legally entitled☞Grease money: cash payments to the right people to oil the machinery of bureaucracy.☞Gifts: are regard as an essential part of civilised negotiation.4Changing business environment and external factors4.1The changing business environment4.1.1The changing competitive environment☞Manufacturing organisations:⏹Before 1970s, domestic markets because of barriers of communication andgeographical distance, few efforts to maximise efficiency and improve management practices.⏹After 1970s, overseas competitors, global networks for acquiring raw materials anddistributing high-quality, low-priced goods.☞Service organisations:⏹Prior to the 1980s: service organisations were government-owned monopolies, wereprotected by a highly-regulated, non-competitive environment.⏹After 1980s: privatisation of government-owned monopolies and deregulation, intensecompetition, led to the requirement of cost management and management accounting information systems.☞Changing product life cycles: competitive environment, technological innovation, increasingly discriminating and sophisticated customer demands.☞Changing customer requirements: Cost efficiency, quality (TQM), time (speedier response to customer requests), innovation☞New management approaches: continuous improvement, employee empowerment; total value-chain analysis☞Advanced manufacturing technology(AMT): encompasses automatic production technology, computer-aided design and manufacturing, flexible manufacturing systems and a wide array of innovative computer equipment.4.1.2The limitation of traditional management accounting techniques in achanging environment☞Cost reporting: costs are generally on a functional basis, the things that businesses do are “process es’ that cut across functional boundaries☞Absorption costing(归纳成本计算法)☞Standard costing: ignores the impact of changing cost structures; doesn’t provide any incentive to try to reduce costs further, is inconsistent with the philosophy of continuous improvement.☞Short-term financial measures: narrowly focused☞Cost accounting methods: trace raw materials to various production stages via WIP. With JIT systems, near-zero inventories, very low batch sizes, cost accounting and recording systems are greatly simplified.☞Performance measures: product the wrong type of response☞Timing: cost of a product is substantially determined when it is being designed, however, management accountants continue to direct their efforts to the production stage.☞Controllability: only a small proportion of ‘direct costs’are genuinely controllable in the short term.☞Customers: many costs are driven by customers, but conventional cost accounting does not recognise this.☞The solution: changes are taking place in management accounting in order to meet the challenge of modern developments.4.2Risk and uncertainty4.2.1Types of risk and uncertainty☞Physical: earthquake, fire, blooding, and equipment breakdown. Climatic changes: global warming, drought;☞Economic: economic environment turn out to be wrong☞Business: lowering of entry barriers; changes in customer/supplier industries; new competitors and factors internal to the firm; management misunderstanding of core competences; volatile cash flows; uncertain returns☞Product life cycle:☞Political: nationalisation, sanctions, civil war, political instability☞Financial:4.2.2Accounting for risk☞Quantify the risk:⏹Rule of thumb methods: express a range of values from worst possible result to bestpossible result with a best estimate lying between these two extremes.⏹Basic probability theory: expresses the likelihood of a forecast result occurring⏹Dispersion or spread values with different possible outcomes: standard deviation.4.2.3Basic probability theory and expected valuesEV=ΣpxP=the probability of an outcome occurringX=the value(profit or loss) of that outcome4.2.4Risk preference☞Risk seeker: is a decision maker who is interested trying to secure the best outcomes no matter how small the chance they may occur☞Risk neutral: a decision maker is concerned with what will be the most likely outcome☞Risk averse: a decision maker acts on the assumption that the worst outcome might occur ☞Risk appetite is the amount of risk an organisation is willing to take on or is prepared to accept in pursuing its strategic objectives.4.2.5Decision rules☞Maximin decision rule: select the alternative that offers the least unattractive worst outcome. Maximise the minimum achievable profit.⏹Problems: risk-averse approach, lead to defensive and conservative, without takinginto account opportunities for maximising profits⏹Ignores the probability of each different outcome taking place☞Maximax: looking for the best outcome. Maximise the maximum achievable profit⏹It ignores probabilities;⏹It is over-optimistic☞Minimax regret rule: minimise the regret from making the wrong decision. Regret is the opportunity lost through making the wrong decision⏹Regret for any combination of action and circumstances=profit for best action in shoescircumstances – profit for the action actually chosen in those circumstances4.3Factors to consider when assessing performance4.3.1Political factors☞Government policy; government plans for divestment(剥夺)/rationalisation; quotas, tariffs, restricting investment or competition; regulate on new products.☞Government policy affecting competition: purchasing decisions; regulations and control;policies to prevent the concentration of too much market share in the hands of one or two producers4.3.2Economic environment☞Gross domestic product: grown or fallen? Affection on the demand of goods/services☞Local economic trends: businesses rationalising or expanding? Rents increasing/falling?The direction of house prices moving? Labour rates☞Inflation: too high to making a plan, uncertain of future financial returns; too low to depressing consumer demand; encouraging investment in domestic industries; high rate leading employees to demand higher money wages to compensate for a fall in the value of their wages☞Interest rates: affect consumer confidence and liquidity, demand; cost of borrowing increasing, reducing profitability;☞Exchange rates: impact on the cost of overseas imports; prices affect overseas customers ☞Government fiscal policy: increasing/decreasing demands; corporate tax policy affecting on the organisation; sales tax(VAT) affecting demand.☞Government spending:☞Business cycle: economic booming or in recession; counter-cyclical industry; the forecast state of the economic4.3.3Funding☞Reasons for being reluctant to obtain further debt finance:⏹Fear the company can’t service the debt, make the required capital and interestpayments on time⏹Can’t use the tax shield, to obtain any tax benefit from interest payments⏹Lacks the asset base to generate additional cash if needed or provide sufficientsecurity⏹Maintain access to the capital markets on good terms.4.3.4Socio-cultural factors☞Class: different social classes have different values。

美国公司法证券法历年经典论文列表

美国是世界上公司法、证券法研究最为发达的国家之一，在美国法学期刊（Law Review & Journals）上每年发表400多篇以公司法和证券法为主题的论文。

自1994年开始，美国的公司法学者每年会投票从中遴选出10篇左右重要的论文，重印于Corporate Practice Commentator，至2008年，已经评选了15年，计177篇论文入选。

以下是每年入选的论文列表：2008年（以第一作者姓名音序为序）：1.Anabtawi, Iman and Lynn Stout. Fiduciary duties for activist shareholders. 60 Stan. L. Rev. 1255-1308 (2008).2.Brummer, Chris. Corporate law preemption in an age of global capital markets. 81 S. Cal. L. Rev. 1067-1114 (2008).3.Choi, Stephen and Marcel Kahan. The market penalty for mutual fund scandals. 87 B.U. L. Rev. 1021-1057 (2007).4.Choi, Stephen J. and Jill E. Fisch. On beyond CalPERS: Survey evidence on the developing role of public pension funds in corporate governance. 61 V and. L. Rev. 315-354 (2008).5.Cox, James D., Randall S. Thoma s and Lynn Bai. There are plaintiffs and…there are plaintiffs: An empirical analysis of securities class action settlements. 61 V and. L. Rev. 355-386 (2008).6.Henderson, M. Todd. Paying CEOs in bankruptcy: Executive compensation when agency costs are low. 101 Nw. U. L. Rev. 1543-1618 (2007).7.Hu, Henry T.C. and Bernard Black. Equity and debt decoupling and empty voting II: Importance and extensions. 156 U. Pa. L. Rev. 625-739 (2008).8.Kahan, Marcel and Edward Rock. The hanging chads of corporate voting. 96 Geo. L.J. 1227-1281 (2008).9.Strine, Leo E., Jr. Toward common sense and common ground? Reflections on the shared interests of managers and labor in a more rational system of corporate governance. 33 J. Corp. L. 1-20 (2007).10.Subramanian, Guhan. Go-shops vs. no-shops in private equity deals: Evidence and implications.63 Bus. Law. 729-760 (2008).2007年：1.Baker, Tom and Sean J. Griffith. The Missing Monitor in Corporate Governance: The Directors’ & Officers’ Liability Insurer. 95 Geo. L.J. 1795-1842 (2007).2.Bebchuk, Lucian A. The Myth of the Shareholder Franchise. 93 V a. L. Rev. 675-732 (2007).3.Choi, Stephen J. and Robert B. Thompson. Securities Litigation and Its Lawyers: Changes During the First Decade After the PSLRA. 106 Colum. L. Rev. 1489-1533 (2006).4.Coffee, John C., Jr. Reforming the Securities Class Action: An Essay on Deterrence and Its Implementation. 106 Colum. L. Rev. 1534-1586 (2006).5.Cox, James D. and Randall S. Thomas. Does the Plaintiff Matter? An Empirical Analysis of Lead Plaintiffs in Securities Class Actions. 106 Colum. L. Rev. 1587-1640 (2006).6.Eisenberg, Theodore and Geoffrey Miller. Ex Ante Choice of Law and Forum: An Empirical Analysis of Corporate Merger Agreements. 59 V and. L. Rev. 1975-2013 (2006).7.Gordon, Jeffrey N. The Rise of Independent Directors in the United States, 1950-2005: Of Shareholder V alue and Stock Market Prices. 59 Stan. L. Rev. 1465-1568 (2007).8.Kahan, Marcel and Edward B. Rock. Hedge Funds in Corporate Governance and Corporate Control. 155 U. Pa. L. Rev. 1021-1093 (2007).ngevoort, Donald C. The Social Construction of Sarbanes-Oxley. 105 Mich. L. Rev. 1817-1855 (2007).10.Roe, Mark J. Legal Origins, Politics, and Modern Stock Markets. 120 Harv. L. Rev. 460-527 (2006).11.Subramanian, Guhan. Post-Siliconix Freeze-outs: Theory and Evidence. 36 J. Legal Stud. 1-26 (2007). (NOTE: This is an earlier working draft. The published article is not freely available, and at SLW we generally respect the intellectual property rights of others.)2006年：1.Bainbridge, Stephen M. Director Primacy and Shareholder Disempowerment. 119 Harv. L. Rev. 1735-1758 (2006).2.Bebchuk, Lucian A. Letting Shareholders Set the Rules. 119 Harv. L. Rev. 1784-1813 (2006).3.Black, Bernard, Brian Cheffins and Michael Klausner. Outside Director Liability. 58 Stan. L. Rev. 1055-1159 (2006).4.Choi, Stephen J., Jill E. Fisch and A.C. Pritchard. Do Institutions Matter? The Impact of the Lead Plaintiff Provision of the Private Securities Litigation Reform Act. 835.Cox, James D. and Randall S. Thomas. Letting Billions Slip Through Y our Fingers: Empirical Evidence and Legal Implications of the Failure of Financial Institutions to Participate in Securities Class Action Settlements. 58 Stan. L. Rev. 411-454 (2005).6.Gilson, Ronald J. Controlling Shareholders and Corporate Governance: Complicating the Comparative Taxonomy. 119 Harv. L. Rev. 1641-1679 (2006).7.Goshen , Zohar and Gideon Parchomovsky. The Essential Role of Securities Regulation. 55 Duke L.J. 711-782 (2006).8.Hansmann, Henry, Reinier Kraakman and Richard Squire. Law and the Rise of the Firm. 119 Harv. L. Rev. 1333-1403 (2006).9.Hu, Henry T. C. and Bernard Black. Empty V oting and Hidden (Morphable) Ownership: Taxonomy, Implications, and Reforms. 61 Bus. Law. 1011-1070 (2006).10.Kahan, Marcel. The Demand for Corporate Law: Statutory Flexibility, Judicial Quality, or Takeover Protection? 22 J. L. Econ. & Org. 340-365 (2006).11.Kahan, Marcel and Edward Rock. Symbiotic Federalism and the Structure of Corporate Law.58 V and. L. Rev. 1573-1622 (2005).12.Smith, D. Gordon. The Exit Structure of V enture Capital. 53 UCLA L. Rev. 315-356 (2005).2005年：1.Bebchuk, Lucian Arye. The case for increasing shareholder power. 118 Harv. L. Rev. 833-914 (2005).2.Bratton, William W. The new dividend puzzle. 93 Geo. L.J. 845-895 (2005).3.Elhauge, Einer. Sacrificing corporate profits in the public interest. 80 N.Y.U. L. Rev. 733-869 (2005).4.Johnson, . Corporate officers and the business judgment rule. 60 Bus. Law. 439-469 (2005).haupt, Curtis J. In the shadow of Delaware? The rise of hostile takeovers in Japan. 105 Colum. L. Rev. 2171-2216 (2005).6.Ribstein, Larry E. Are partners fiduciaries? 2005 U. Ill. L. Rev. 209-251.7.Roe, Mark J. Delaware?s politics. 118 Harv. L. Rev. 2491-2543 (2005).8.Romano, Roberta. The Sarbanes-Oxley Act and the making of quack corporate governance. 114 Y ale L.J. 1521-1611 (2005).9.Subramanian, Guhan. Fixing freezeouts. 115 Y ale L.J. 2-70 (2005).10.Thompson, Robert B. and Randall S. Thomas. The public and private faces of derivative lawsuits. 57 V and. L. Rev. 1747-1793 (2004).11.Weiss, Elliott J. and J. White. File early, then free ride: How Delaware law (mis)shapes shareholder class actions. 57 V and. L. Rev. 1797-1881 (2004).2004年：1Arlen, Jennifer and Eric Talley. Unregulable defenses and the perils of shareholder choice. 152 U. Pa. L. Rev. 577-666 (2003).2.Bainbridge, Stephen M. The business judgment rule as abstention doctrine. 57 V and. L. Rev. 83-130 (2004).3.Bebchuk, Lucian Arye and Alma Cohen. Firms' decisions where to incorporate. 46 J.L. & Econ. 383-425 (2003).4.Blair, Margaret M. Locking in capital: what corporate law achieved for business organizers in the nineteenth century. 51 UCLA L. Rev. 387-455 (2003).5.Gilson, Ronald J. and Jeffrey N. Gordon. Controlling shareholders. 152 U. Pa. L. Rev. 785-843 (2003).6.Roe, Mark J. Delaware 's competition. 117 Harv. L. Rev. 588-646 (2003).7.Sale, Hillary A. Delaware 's good faith. 89 Cornell L. Rev. 456-495 (2004).8.Stout, Lynn A. The mechanisms of market inefficiency: an introduction to the new finance. 28 J. Corp. L. 635-669 (2003).9.Subramanian, Guhan. Bargaining in the shadow of takeover defenses. 113 Y ale L.J. 621-686 (2003).10.Subramanian, Guhan. The disappearing Delaware effect. 20 J.L. Econ. & Org. 32-59 (2004)11.Thompson, Robert B. and Randall S. Thomas. The new look of shareholder litigation: acquisition-oriented class actions. 57 V and. L. Rev. 133-209 (2004).2003年：1.A yres, Ian and Stephen Choi. Internalizing outsider trading. 101 Mich. L. Rev. 313-408 (2002).2.Bainbridge, Stephen M. Director primacy: The means and ends of corporate governance. 97 Nw. U. L. Rev. 547-606 (2003).3.Bebchuk, Lucian, Alma Cohen and Allen Ferrell. Does the evidence favor state competition in corporate law? 90 Cal. L. Rev. 1775-1821 (2002).4.Bebchuk, Lucian Arye, John C. Coates IV and Guhan Subramanian. The Powerful Antitakeover Force of Staggered Boards: Further findings and a reply to symposium participants. 55 Stan. L. Rev. 885-917 (2002).5.Choi, Stephen J. and Jill E. Fisch. How to fix Wall Street: A voucher financing proposal for securities intermediaries. 113 Y ale L.J. 269-346 (2003).6.Daines, Robert. The incorporation choices of IPO firms. 77 N.Y.U. L. Rev.1559-1611 (2002).7.Gilson, Ronald J. and David M. Schizer. Understanding venture capital structure: A taxexplanation for convertible preferred stock. 116 Harv. L. Rev. 874-916 (2003).8.Kahan, Marcel and Ehud Kamar. The myth of state competition in corporate law. 55 Stan. L. Rev. 679-749 (2002).ngevoort, Donald C. Taming the animal spirits of the stock markets: A behavioral approach to securities regulation. 97 Nw. U. L. Rev. 135-188 (2002).10.Pritchard, A.C. Justice Lewis F. Powell, Jr., and the counterrevolution in the federal securities laws. 52 Duke L.J. 841-949 (2003).11.Thompson, Robert B. and Hillary A. Sale. Securities fraud as corporate governance: Reflections upon federalism. 56 V and. L. Rev. 859-910 (2003).2002年：1.Allen, William T., Jack B. Jacobs and Leo E. Strine, Jr. Function over Form: A Reassessment of Standards of Review in Delaware Corporation Law. 26 Del. J. Corp. L. 859-895 (2001) and 56 Bus. Law. 1287 (2001).2.A yres, Ian and Joe Bankman. Substitutes for Insider Trading. 54 Stan. L. Rev. 235-254 (2001).3.Bebchuk, Lucian Arye, Jesse M. Fried and David I. Walker. Managerial Power and Rent Extraction in the Design of Executive Compensation. 69 U. Chi. L. Rev. 751-846 (2002).4.Bebchuk, Lucian Arye, John C. Coates IV and Guhan Subramanian. The Powerful Antitakeover Force of Staggered Boards: Theory, Evidence, and Policy. 54 Stan. L. Rev. 887-951 (2002).5.Black, Bernard and Reinier Kraakman. Delaware’s Takeover Law: The Uncertain Search for Hidden V alue. 96 Nw. U. L. Rev. 521-566 (2002).6.Bratton, William M. Enron and the Dark Side of Shareholder V alue. 76 Tul. L. Rev. 1275-1361 (2002).7.Coates, John C. IV. Explaining V ariation in Takeover Defenses: Blame the Lawyers. 89 Cal. L. Rev. 1301-1421 (2001).8.Kahan, Marcel and Edward B. Rock. How I Learned to Stop Worrying and Love the Pill: Adaptive Responses to Takeover Law. 69 U. Chi. L. Rev. 871-915 (2002).9.Kahan, Marcel. Rethinking Corporate Bonds: The Trade-off Between Individual and Collective Rights. 77 N.Y.U. L. Rev. 1040-1089 (2002).10.Roe, Mark J. Corporate Law’s Limits. 31 J. Legal Stud. 233-271 (2002).11.Thompson, Robert B. and D. Gordon Smith. Toward a New Theory of the Shareholder Role: "Sacred Space" in Corporate Takeovers. 80 Tex. L. Rev. 261-326 (2001).2001年：1.Black, Bernard S. The legal and institutional preconditions for strong securities markets. 48 UCLA L. Rev. 781-855 (2001).2.Coates, John C. IV. Takeover defenses in the shadow of the pill: a critique of the scientific evidence. 79 Tex. L. Rev. 271-382 (2000).3.Coates, John C. IV and Guhan Subramanian. A buy-side model of M&A lockups: theory and evidence. 53 Stan. L. Rev. 307-396 (2000).4.Coffee, John C., Jr. The rise of dispersed ownership: the roles of law and the state in the separation of ownership and control. 111 Y ale L.J. 1-82 (2001).5.Choi, Stephen J. The unfounded fear of Regulation S: empirical evidence on offshore securities offerings. 50 Duke L.J. 663-751 (2000).6.Daines, Robert and Michael Klausner. Do IPO charters maximize firm value? Antitakeover protection in IPOs. 17 J.L. Econ. & Org. 83-120 (2001).7.Hansmann, Henry and Reinier Kraakman. The essential role of organizational law. 110 Y ale L.J. 387-440 (2000).ngevoort, Donald C. The human nature of corporate boards: law, norms, and the unintended consequences of independence and accountability. 89 Geo. L.J. 797-832 (2001).9.Mahoney, Paul G. The political economy of the Securities Act of 1933. 30 J. Legal Stud. 1-31 (2001).10.Roe, Mark J. Political preconditions to separating ownership from corporate control. 53 Stan. L. Rev. 539-606 (2000).11.Romano, Roberta. Less is more: making institutional investor activism a valuable mechanism of corporate governance. 18 Y ale J. on Reg. 174-251 (2001).2000年：1.Bratton, William W. and Joseph A. McCahery. Comparative Corporate Governance and the Theory of the Firm: The Case Against Global Cross Reference. 38 Colum. J. Transnat’l L. 213-297 (1999).2.Coates, John C. IV. Empirical Evidence on Structural Takeover Defenses: Where Do We Stand?54 U. Miami L. Rev. 783-797 (2000).3.Coffee, John C., Jr. Privatization and Corporate Governance: The Lessons from Securities Market Failure. 25 J. Corp. L. 1-39 (1999).4.Fisch, Jill E. The Peculiar Role of the Delaware Courts in the Competition for Corporate Charters. 68 U. Cin. L. Rev. 1061-1100 (2000).5.Fox, Merritt B. Retained Mandatory Securities Disclosure: Why Issuer Choice Is Not Investor Empowerment. 85 V a. L. Rev. 1335-1419 (1999).6.Fried, Jesse M. Insider Signaling and Insider Trading with Repurchase Tender Offers. 67 U. Chi. L. Rev. 421-477 (2000).7.Gulati, G. Mitu, William A. Klein and Eric M. Zolt. Connected Contracts. 47 UCLA L. Rev. 887-948 (2000).8.Hu, Henry T.C. Faith and Magic: Investor Beliefs and Government Neutrality. 78 Tex. L. Rev. 777-884 (2000).9.Moll, Douglas K. Shareholder Oppression in Close Corporations: The Unanswered Question of Perspective. 53 V and. L. Rev. 749-827 (2000).10.Schizer, David M. Executives and Hedging: The Fragile Legal Foundation of Incentive Compatibility. 100 Colum. L. Rev. 440-504 (2000).11.Smith, Thomas A. The Efficient Norm for Corporate Law: A Neotraditional Interpretation of Fiduciary Duty. 98 Mich. L. Rev. 214-268 (1999).12.Thomas, Randall S. and Kenneth J. Martin. The Determinants of Shareholder V oting on Stock Option Plans. 35 Wake Forest L. Rev. 31-81 (2000).13.Thompson, Robert B. Preemption and Federalism in Corporate Governance: Protecting Shareholder Rights to V ote, Sell, and Sue. 62 Law & Contemp. Probs. 215-242 (1999).1999年（以第一作者姓名音序为序）：1.Bankman, Joseph and Ronald J. Gilson. Why Start-ups? 51 Stan. L. Rev. 289-308 (1999).2.Bhagat, Sanjai and Bernard Black. The Uncertain Relationship Between Board Composition and Firm Performance. 54 Bus. Law. 921-963 (1999).3.Blair, Margaret M. and Lynn A. Stout. A Team Production Theory of Corporate Law. 85 V a. L. Rev. 247-328 (1999).4.Coates, John C., IV. “Fair V alue” As an A voidable Rule of Corporate Law: Minority Discounts in Conflict Transactions. 147 U. Pa. L. Rev. 1251-1359 (1999).5.Coffee, John C., Jr. The Future as History: The Prospects for Global Convergence in Corporate Governance and Its Implications. 93 Nw. U. L. Rev. 641-707 (1999).6.Eisenberg, Melvin A. Corporate Law and Social Norms. 99 Colum. L. Rev. 1253-1292 (1999).7.Hamermesh, Lawrence A. Corporate Democracy and Stockholder-Adopted By-laws: Taking Back the Street? 73 Tul. L. Rev. 409-495 (1998).8.Krawiec, Kimberly D. Derivatives, Corporate Hedging, and Shareholder Wealth: Modigliani-Miller Forty Y ears Later. 1998 U. Ill. L. Rev. 1039-1104.ngevoort, Donald C. Rereading Cady, Roberts: The Ideology and Practice of Insider Trading Regulation. 99 Colum. L. Rev. 1319-1343 (1999).ngevoort, Donald C. Half-Truths: Protecting Mistaken Inferences By Investors and Others.52 Stan. L. Rev. 87-125 (1999).11.Talley, Eric. Turning Servile Opportunities to Gold: A Strategic Analysis of the Corporate Opportunities Doctrine. 108 Y ale L.J. 277-375 (1998).12.Williams, Cynthia A. The Securities and Exchange Commission and Corporate Social Transparency. 112 Harv. L. Rev. 1197-1311 (1999).1998年：1.Carney, William J., The Production of Corporate Law, 71 S. Cal. L. Rev. 715-780 (1998).2.Choi, Stephen, Market Lessons for Gatekeepers, 92 Nw. U. L. Rev. 916-966 (1998).3.Coffee, John C., Jr., Brave New World?: The Impact(s) of the Internet on Modern Securities Regulation. 52 Bus. Law. 1195-1233 (1997).ngevoort, Donald C., Organized Illusions: A Behavioral Theory of Why Corporations Mislead Stock Market Investors (and Cause Other Social Harms). 146 U. Pa. L. Rev. 101-172 (1997).ngevoort, Donald C., The Epistemology of Corporate-Securities Lawyering: Beliefs, Biases and Organizational Behavior. 63 Brook. L. Rev. 629-676 (1997).6.Mann, Ronald J. The Role of Secured Credit in Small-Business Lending. 86 Geo. L.J. 1-44 (1997).haupt, Curtis J., Property Rights in Firms. 84 V a. L. Rev. 1145-1194 (1998).8.Rock, Edward B., Saints and Sinners: How Does Delaware Corporate Law Work? 44 UCLA L. Rev. 1009-1107 (1997).9.Romano, Roberta, Empowering Investors: A Market Approach to Securities Regulation. 107 Y ale L.J. 2359-2430 (1998).10.Schwab, Stewart J. and Randall S. Thomas, Realigning Corporate Governance: Shareholder Activism by Labor Unions. 96 Mich. L. Rev. 1018-1094 (1998).11.Skeel, David A., Jr., An Evolutionary Theory of Corporate Law and Corporate Bankruptcy. 51 V and. L. Rev. 1325-1398 (1998).12.Thomas, Randall S. and Martin, Kenneth J., Should Labor Be Allowed to Make Shareholder Proposals? 73 Wash. L. Rev. 41-80 (1998).1997年：1.Alexander, Janet Cooper, Rethinking Damages in Securities Class Actions, 48 Stan. L. Rev. 1487-1537 (1996).2.Arlen, Jennifer and Kraakman, Reinier, Controlling Corporate Misconduct: An Analysis of Corporate Liability Regimes, 72 N.Y.U. L. Rev. 687-779 (1997).3.Brudney, Victor, Contract and Fiduciary Duty in Corporate Law, 38 B.C. L. Rev. 595-665 (1997).4.Carney, William J., The Political Economy of Competition for Corporate Charters, 26 J. Legal Stud. 303-329 (1997).5.Choi, Stephen J., Company Registration: Toward a Status-Based Antifraud Regime, 64 U. Chi. L. Rev. 567-651 (1997).6.Fox, Merritt B., Securities Disclosure in a Globalizing Market: Who Should Regulate Whom. 95 Mich. L. Rev. 2498-2632 (1997).7.Kahan, Marcel and Klausner, Michael, Lockups and the Market for Corporate Control, 48 Stan. L. Rev. 1539-1571 (1996).8.Mahoney, Paul G., The Exchange as Regulator, 83 V a. L. Rev. 1453-1500 (1997).haupt, Curtis J., The Market for Innovation in the United States and Japan: V enture Capital and the Comparative Corporate Governance Debate, 91 Nw. U.L. Rev. 865-898 (1997).10.Skeel, David A., Jr., The Unanimity Norm in Delaware Corporate Law, 83 V a. L. Rev. 127-175 (1997).1996年：1.Black, Bernard and Reinier Kraakman A Self-Enforcing Model of Corporate Law, 109 Harv. L. Rev. 1911 (1996)2.Gilson, Ronald J. Corporate Governance and Economic Efficiency: When Do Institutions Matter?, 74 Wash. U. L.Q. 327 (1996)3. Hu, Henry T.C. Hedging Expectations: "Derivative Reality" and the Law and Finance of the Corporate Objective, 21 J. Corp. L. 3 (1995)4.Kahan, Marcel & Michael Klausner Path Dependence in Corporate Contracting: Increasing Returns, Herd Behavior and Cognitive Biases, 74 Wash. U. L.Q. 347 (1996)5.Kitch, Edmund W. The Theory and Practice of Securities Disclosure, 61 Brooklyn L. Rev. 763 (1995)ngevoort, Donald C. Selling Hope, Selling Risk: Some Lessons for Law From Behavioral Economics About Stockbrokers and Sophisticated Customers, 84 Cal. L. Rev. 627 (1996)7.Lin, Laura The Effectiveness of Outside Directors as a Corporate Governance Mechanism: Theories and Evidence, 90 Nw. U.L. Rev. 898 (1996)lstein, Ira M. The Professional Board, 50 Bus. Law 1427 (1995)9.Thompson, Robert B. Exit, Liquidity, and Majority Rule: Appraisal's Role in Corporate Law, 84 Geo. L.J. 1 (1995)10.Triantis, George G. and Daniels, Ronald J. The Role of Debt in Interactive Corporate Governance. 83 Cal. L. Rev. 1073 (1995)1995年：公司法：1.Arlen, Jennifer and Deborah M. Weiss A Political Theory of Corporate Taxation,. 105 Y ale L.J. 325-391 (1995).2.Elson, Charles M. The Duty of Care, Compensation, and Stock Ownership, 63 U. Cin. L. Rev. 649 (1995).3.Hu, Henry T.C. Heeding Expectations: "Derivative Reality" and the Law and Finance of the Corporate Objective, 73 Tex. L. Rev. 985-1040 (1995).4.Kahan, Marcel The Qualified Case Against Mandatory Terms in Bonds, 89 Nw. U.L. Rev. 565-622 (1995).5.Klausner, Michael Corporations, Corporate Law, and Networks of Contracts, 81 V a. L. Rev. 757-852 (1995).6.Mitchell, Lawrence E. Cooperation and Constraint in the Modern Corporation: An Inquiry Into the Causes of Corporate Immorality, 73 Tex. L. Rev. 477-537 (1995).7.Siegel, Mary Back to the Future: Appraisal Rights in the Twenty-First Century, 32 Harv. J. on Legis. 79-143 (1995).证券法：1.Grundfest, Joseph A. Why Disimply? 108 Harv. L. Rev. 727-747 (1995).2.Lev, Baruch and Meiring de V illiers Stock Price Crashes and 10b-5 Damages: A Legal Economic, and Policy Analysis, 47 Stan. L. Rev. 7-37 (1994).3.Mahoney, Paul G. Mandatory Disclosure as a Solution to Agency Problems, 62 U. Chi. L. Rev. 1047-1112 (1995).4.Seligman, Joel The Merits Do Matter, 108 Harv. L. Rev. 438 (1994).5.Seligman, Joel The Obsolescence of Wall Street: A Contextual Approach to the Evolving Structure of Federal Securities Regulation, 93 Mich. L. Rev. 649-702 (1995).6.Stout, Lynn A. Are Stock Markets Costly Casinos? Disagreement, Mark Failure, and Securities Regulation, 81 V a. L. Rev. 611 (1995).7.Weiss, Elliott J. and John S. Beckerman Let the Money Do the Monitoring: How Institutional Investors Can Reduce Agency Costs in Securities Class Actions, 104 Y ale L.J. 2053-2127 (1995).1994年：公司法：1.Fraidin, Stephen and Hanson, Jon D. Toward Unlocking Lockups, 103 Y ale L.J. 1739-1834 (1994)2.Gordon, Jeffrey N. Institutions as Relational Investors: A New Look at Cumulative V oting, 94 Colum. L. Rev. 124-192 (1994)3.Karpoff, Jonathan M., and Lott, John R., Jr. The Reputational Penalty Firms Bear From Committing Criminal Fraud, 36 J.L. & Econ. 757-802 (1993)4.Kraakman, Reiner, Park, Hyun, and Shavell, Steven When Are Shareholder Suits in Shareholder Interests?, 82 Geo. L.J. 1733-1775 (1994)5.Mitchell, Lawrence E. Fairness and Trust in Corporate Law, 43 Duke L.J. 425- 491 (1993)6.Oesterle, Dale A. and Palmiter, Alan R. Judicial Schizophrenia in Shareholder V oting Cases, 79 Iowa L. Rev. 485-583 (1994)7. Pound, John The Rise of the Political Model of Corporate Governance and Corporate Control, 68 N.Y.U. L. Rev. 1003-1071 (1993)8.Skeel, David A., Jr. Rethinking the Line Between Corporate Law and Corporate Bankruptcy, 72 Tex. L. Rev. 471-557 (1994)9.Thompson, Robert B. Unpacking Limited Liability: Direct and V icarious Liability of Corporate Participants for Torts of the Enterprise, 47 V and. L. Rev. 1-41 (1994)证券法：1.Alexander, Janet Cooper The V alue of Bad News in Securities Class Actions, 41 UCLA L.Rev. 1421-1469 (1994)2.Bainbridge, Stephen M. Insider Trading Under the Restatement of the Law Governing Lawyers, 19 J. Corp. L. 1-40 (1993)3.Black, Bernard S. and Coffee, John C. Jr. Hail Britannia?: Institutional Investor Behavior Under Limited Regulation, 92 Mich. L. Rev. 1997-2087 (1994)4.Booth, Richard A. The Efficient Market, portfolio Theory, and the Downward Sloping Demand Hypothesis, 68 N.Y.U. L. Rev. 1187-1212 (1993)5.Coffee, John C., Jr. The SEC and the Institutional Investor: A Half-Time Report, 15 Cardozo L. Rev 837-907 (1994)6.Fox, Merritt B. Insider Trading Deterrence V ersus Managerial Incentives: A Unified Theory of Section 16(b), 92 Mich. L. Rev. 2088-2203 (1994)7.Grundfest, Joseph A. Disimplying Private Rights of Action Under the Federal Securities Laws: The Commission's Authority, 107 Harv. L. Rev. 961-1024 (1994)8.Macey, Jonathan R. Administrative Agency Obsolescence and Interest Group Formation: A Case Study of the SEC at Sixty, 15 Cardozo L. Rev. 909-949 (1994)9.Rock, Edward B. Controlling the Dark Side of Relational Investing, 15 Cardozo L. Rev. 987-1031 (1994)。

FairValueMeasurementFeedbackstatement_May2011

May 2011Project Summary and Feedback StatementIFRS 13 Fair Value MeasurementAt a glanceWe, the International Accounting Standards Board (IASB), issued IFRS 13Fair Value Measurement in May 2011.IFRS 13 deﬁ nes fair value, sets out in a single IFRS a framework for measuring fair value and requires disclosures about fair value measurements.IFRS 13 applies when other IFRSs require or permit fair value measurements.It does not introduce any new requirements to measure an asset ora liability at fair value, change what is measured at fair value in IFRSs or address how to present changes in fair value.We began the project in 2005 as part of our joint efforts with the US national standard-setter, the Financial Accounting Standards Board (FASB), to create a common set of high quality global accounting standards. The project was part of the Memorandumof Understanding (MoU) between theboards. As a result of our joint work, wealigned International Financial ReportingStandards (IFRSs) and US generallyaccepted accounting principles(GAAP) in this important area ofaccounting. The new requirements resultin IFRSs and US GAAP having the samedeﬁ nition and meaning of fair value andthe same disclosure requirements aboutfair value measurements.Having the same fair value measurementand disclosure requirements willreduce diversity in application, which willimprove the comparability of ﬁ nancialstatements prepared using IFRSs andthose using US GAAP.The global ﬁ nancial crisis emphasisedthe importance of having commonfair value measurement anddisclosure requirements—withidentical wording—in IFRSs andUS GAAP. IFRS 13 provides clearand consistent guidance formeasuring fair value and addressingvaluation uncertainty in marketsthat are no longer active. It alsoincreases the transparency of fairvalue measurements by requiringdetailed disclosures about fair valuesderived using models.2|Fair Value Measurement | May 2011Project time lineFair Value Measurement | May 2011| 320052007200820092010Sep 2005IASB addedproject to agenda May 2007Comment period ended for IASB discussion paper Nov 2007SFAS 157 effective for ﬁ nancial instrumentsMay 2008IASB set up Fair Value Expert Advisory Pane l Oct 2008IASB Panel report on measuring fair value in inactive markets Oct 2008FASB issued FSP FAS 157-3Nov 2008SFAS 157 effective for non-ﬁ nancial assets and liabilitiesApr 2009FASB issued FSP FAS 157-4May 2009IASB published FVM exposure draftSep 2009Comment period ended for IASB exposure draft Oct 2009IASB and FASB agreed to work jointly to align FVM guidance Nov–Dec 2009IASB round-table meetingsJune 2010IASB published disclosurere-exposure draft June 2010FASB published convergenceexposure draft2011May 2011IASB issued IFRS 13May 2011 FASB issuedASU No. 2011-0420131 Jan 2013IFRS 13 effective (earlier application permitted)2006Sep 2006FASB issued SFAS 157Nov 2006IASB published discussion paperWhy we undertook this projectSome IFRSs require or permit entities to measure or disclose the fair value of assets, liabilities ortheir own equity instruments. Because we (and our predecessor body) developed those standards over many years, the requirements for measuring fair value and for disclosing information about fair values were dispersed across many standards and in many cases those standards did not articulate a clear measurement or disclosure objective.The goals of the fair valuemeasurement project were:• to reduce complexity and improveconsistency in the applicationof fair value measurementprinciples by having a single setof requirements for all fair valuemeasurements;• to communicate themeasurement objective moreclearly by clarifying the deﬁ nitionof fair value;• to improve transparency byenhancing disclosures about fairvalue measurements; and• to increase the convergence ofIFRSs and US GAAP.As a result, some IFRSs containedlimited information about how tomeasure fair value, whereas otherscontained extensive information,which was not always consistentacross the standards.4|Fair Value Measurement | May 2011Although the fair value measurement project was added to our agenda before the global ﬁ nancial crisis began, the crisis emphasised the importance of having commonfair value measurement and disclosure requirements in IFRSsand US GAAP. In particular, the global ﬁ nancial crisis highlightedthe need for:• clarifying how to measure fair value when themarket for an asset or liability becomes less active;and• improving the transparency of fair valuemeasurements through disclosures aboutmeasurement uncertainty.Consistently with the recommendations of the Groupof Twenty (G20) Leaders, the Financial Stability Boardand the IASB’s and FASB’s Financial Crisis AdvisoryGroup (FCAG), we worked with the FASB to addressthose issues.In May 2008 we established a Fair Value ExpertAdvisory Panel that included preparers, auditors andusers of ﬁ nancial statements, as well as regulators.The Panel’s remit was to help us:• review best practices in the area of valuationtechniques; and• formulate any necessary additional practice guidanceon valuation methods for ﬁ nancial instruments andrelated disclosures when markets are nolonger active.In October 2008 our staff published a reportsummarising the Panel’s discussions. The report,Measuring and disclosing the fair value of ﬁ nancialinstruments in markets that are no longer active,summarised the valuation and disclosure practicesundertaken by large ﬁ nancial institutions in theﬁ nancial crisis. The requirements in IFRS 13 areconsistent with that report.Responding to the global ﬁ nancial crisisFair Value Measurement | May 2011|56 | Fair Value Measurement | May 2011Level 1Quoted prices in active markets for identical assets and liabilities. Level 1 inputs must be used without adjustment whenever available.Level 2Inputs not included within Level 1 that are observable for the asset or liability, either directly or indirectly.Level 3Unobservable inputs, including the entity’s own data, which are adjusted if necessary to reﬂ ect market participants’ assumptions.IFRS 13 will help increase transparency when entities use models to measure fair value, particularly when users need more information about measurement uncertainty, such as when the market for an asset or a liability has become less active.IFRS 13 requires entities to disclose information about the valuation techniques and inputs used to measure fair value, as well as information about the uncertainty inherent in fair value measurements (which was of particular concern during the global ﬁ nancial crisis). Some of those disclosures, including the fair value hierarchy, were already introduced in March 2009 through an amendment to IFRS 7 Financial Instruments: Disclosures . Those disclosures have been relocated to IFRS 13.The requirements in IFRS 13 also incorporate the guidance in a FASB Staff Position (FSP) issued in April 2009.Providing additional information about Level 3 fair value measurements to users of ﬁ nancial statements will help improve conﬁ dence in those measurements.Summary of the main changes from the exposure draftFair Value Measurement | May 2011|78|Fair Value Measurement | May 2011With the FASB we undertook extensive outreach activities. Those outreach activities, combined with the matters raised in the comment letters onthe exposure draft, provided important information for developing IFRS 13. As a result, some of the requirements in IFRS 13 are different from those proposed in theexposure draft.The most prevalent comment received was that we should work with the FASB to resolve any differences between the proposals in our exposure draft andthe requirements in US GAAP (Topic 820 Fair Value Measurements and Disclosures in the FASB Accounting Standards Codiﬁ cation®). Topic 820 codiﬁ ed FASB Statement of Financial Accounting Standards No. 157 Fair Value Measurements (SFAS 157).As a result, in October 2009 both boards agreed towork jointly to achieve common requirements in IFRSsand US GAAP. Consequently, the FASB agreed to makeamendments to Topic 820 as necessary (in June 2010the FASB published a proposed Accounting StandardsUpdate (ASU) of those amendments).Other comments indicated that many viewed theproposals in the exposure draft, particularly therevised deﬁ nition of fair value, as a change tocurrent practice even though we believed that themost signiﬁ cant change would be to move the fairvalue measurement guidance from individual IFRSs toa single IFRS. Although IFRS 13 describes some of thefair value measurement and disclosure requirementsin a different way, there are very few changes tothose requirements. Instead, IFRS 13 clariﬁ es themeasurement objective and harmonises the disclosurerequirements, both of which we think will improveconsistency in application.In the pages that follow we outline the moresigniﬁ cant matters raised and how we responded:• Deﬁ ning fair value as an exit price• Principal and most advantageous markets• Measuring the fair value of a liability• Measuring the fair value of ﬁ nancial instrumentswithin a portfolio• Premiums and discounts• Measuring fair value when markets become inactive• Disclosures about fair value measurementsFeedback statementFair Value Measurement | May 2011|910 | Fair Value Measurement | May 2011Deﬁ ning fair value as an exit priceRespondents’ commentsMany respondents thought the proposal to deﬁ nefair value as a market-based current exit price was appropriate because it would retain the notion of an exchange between unrelated, knowledgeable and willing parties in the current deﬁ nition of fair value in IFRSs, and it would provide a clearer measurement objective. Other respondents thought an entry price would be more appropriate in some situations (eg at initial recognition).Some respondents were concerned that an exit price deﬁ nition of fair value and the proposed measurement guidance for applying that deﬁ nition were more relevant for ﬁ nancial instruments than for non-ﬁ nancial assets and liabilities.Our responseOur starting point for deﬁ ning fair value was to usethe current exit price deﬁ nition in US GAAP. However, we needed to ensure that such a deﬁ nition would be appropriate where fair value was used in a particular IFRS. In our efforts to deﬁ ne fair value with a clear measurement objective we undertook a standard-by-standard review of all IFRSs that required or permitted fair value measurements. We asked interested parties to provide input on that review given their experience in applying the fair value measurement guidance for all types of assets and liabilities, including ﬁ nancial instruments and non-ﬁ nancial assets and liabilities. That input helped us determine the scope of IFRS 13.Because some respondents to the exposure draft had conceptual objections to using an exit price deﬁ nition of fair value at initial recognition, we initially considered splitting fair value into two measurements (a current exit price and a current entry price) depending on the circumstances.Concerns about distinguishing between an entry price and an exit price often relate to potential differences between an actual acquisition price (eg the pricepaid by an entity to buy an asset, which is an entry price) and a hypothetical sales price (eg the price that would be received to sell that asset, which is an exit price). IFRS 13 describes situations that might lead to differences between entry and exit prices, and other IFRSs determine how to report those differences.In determining how to deﬁ ne fair value, we considered not only the conceptual differences between entry and exit prices, but also the practical differences between them. Thus, we considered whether there would actually be a difference in the amounts recognisedin the ﬁ nancial statements. The work we did in the project to revise IFRS 3 Business Combinations in 2008 was helpful in that analysis.Ultimately, the standard-by-standard review resultedin a decision to exclude from the scope of IFRS 13share-based payment transactions within the scopeof IFRS 2 Share-based Payment and leasing transactionswithin the scope of IAS 17 Leases. Furthermore, giventhat the focus of the fair value measurement projectwas to clarify the measurement objective, we decidedto deﬁ ne fair value as an exit price and emphasise thatfair value:• is a market-based measurement, not anentity-speciﬁ c measurement; and• takes into account the market conditions at themeasurement date.The deﬁ nition of fair value in IFRS 13 is the same as inUS GAAP.We concluded that even if there are conceptualdifferences between an entry price and an exit price,in most cases the resulting measurement under bothobjectives would be the same. Consequently, it didnot seem necessary to have two current market-baseddeﬁ nitions of value with different focuses (ie one onthe entry side of the transaction and one on the exitside of the transaction), so we decided to deﬁ ne fairvalue as an exit price. An exit price deﬁ nition of fairvalue also has the beneﬁ t of removing entity-speciﬁ cfactors that might exist in an entry price.Furthermore, we concluded that some aspects ofthe measurement guidance were applicable only toparticular types of assets or liabilities. For example, aprincipal market notion applies to any item, whetherit is an asset or a liability, and whether it is of aﬁ nancial or non-ﬁ nancial nature. In contrast, thehighest and best use notion applies to non-ﬁ nancialassets and is not relevant for ﬁ nancial assets or forliabilities. IFRS 13 addresses this by distinguishingbetween types of assets or liabilities when necessary.Fair Value Measurement | May 2011|11Principal and most advantageous marketsThe exposure draft proposed that fair value should be measured on the basis of a transaction to sell an asset or transfer a liability that takes place in the most advantageous market to which the entity has access. The exposure draft presumed that the market in which the entity normally enters into transactions is the most advantageous marketand that an entity may assume that the principal market for the asset or a liability is the most advantageous market.That was different from the approach in US GAAP, which referred to the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability.Respondents’ commentsMany respondents agreed with the most advantageousmarket notion because most entities enter intotransactions that maximise the price they receive foran asset or minimise the price they pay to discharge aliability. Furthermore, a most advantageous marketnotion works regardless of the level of activity in amarket or whether the market for an asset or liabilityis observable.However, some respondents thought it might bedifﬁ cult to identify and select the most advantageousmarket when an asset or liability is exchanged inmultiple markets. Others were unsure whether themost advantageous market had to be used or howthe market in which the entity normally entersinto transactions relates to the principal or mostadvantageous market. In general, respondentspreferred the approach in US GAAP.Our responseAlthough we think that in most cases the principalmarket and the most advantageous market wouldbe the same, we agreed that the focus should be onthe principal market for the asset or liability. Theprincipal market is the market with the greatestvolume and level of activity for the asset or liability.We concluded that the principal market wouldprovide the most representative input for a fair valuemeasurement because that market is the most liquidmarket for the asset or liability.Given the feedback received and the need to developcommon fair value measurement guidance in IFRSsand US GAAP, we decided to specify that a fair valuemeasurement assumes that the transaction to sellan asset or to transfer a liability takes place in theprincipal market for the asset or liability or, in theabsence of a principal market, the most advantageousmarket for the asset or liability.There is a presumption in IFRS 13 that the principalmarket is the market in which an entity normallyenters into transactions for the asset or liability unlessthere is evidence that another market has a greatervolume and level of activity.12|Fair Value Measurement | May 2011Measuring the fair value of a liabilityThe exposure draft proposed the following with respect to liabilities:• An entity can estimate a transfer pricefor a liability using the fair value of the corresponding asset or the amount that would be incurred in fulﬁ lling the obligation.• The fair value of a liability reﬂ ects the riskthat an entity will not fulﬁ l an obligation (non-performance risk).• The fair value of a liability should not be adjusted for the effect of a restriction on its transfer if that restriction is already included in the other inputs to the fair value measurement. That is consistent with the approach inUS GAAP (Topic 820 was amended in August 2009 to provide additional guidance about measuring the fair value of liabilities). Respondents’ commentsThe views on the proposals to deﬁ ne the fair value of aliability as a transfer price and to include the effect ofnon-performance risk were mixed. Many respondentsthought that fair value, when deﬁ ned as a transferprice for liabilities, would not be an appropriatemeasurement basis for most liabilities and wouldonly be appropriate for those liabilities that can andare intended to be transferred.Although many did not agree with a transfernotion for liabilities, respondents generallyfound the guidance about using the fair value ofthe corresponding asset or a fulﬁ lment amountto measure the fair value of a liability helpful,particularly because that is typically how they thinkabout the value of a liability. Many of the participantsat our round-table meetings in the US said they hadfound the additional guidance in US GAAP useful.In addition, although few respondents questionedthe usefulness of reﬂ ecting non-performance risk inthe fair value measurement of a liability at initialrecognition, many questioned the usefulness of doingso after initial recognition. In particular, they believedthat including the effects of changes in an entity’sown credit risk or changes in the price of credit inthe fair value of a liability and recognising thosechanges in proﬁ t or loss leads to counter-intuitive andpotentially confusing reporting (ie gains for creditdeterioration and losses for credit improvements).Fair Value Measurement | May 2011|13Our responseBecause the measurement guidance for liabilities in US GAAP was consistent with the proposals in the exposure draft, we worked with the FASB to develop a combination of the two.As a result, IFRS 13 states that in the absence of a quoted price in an active market to transfer the identical liability, an entity would measure the fair value of the liability as follows:• using the quoted price in an active market for the identical liability held by another party as an asset, if that price is available.• if that price is not available, using other observable inputs, such as the quoted price in a market that is not active for the identical liability held by another party as an asset.• if neither of those observable prices is available, using another valuation technique (eg using market comparable data or discounted cash ﬂ ows). With respect to non-performance risk, IFRS 13carries forward the proposal in the exposure draft andstates that the fair value of a liability reﬂ ectsthe effect of non-performance risk. Concerns aboutreporting changes in an entity’s own credit risk in thestatement of comprehensive income were addressed indeveloping IFRS 9 Financial Instruments, issued in 2010.IFRS 13 also states that the fair value of a liabilityshould not be adjusted further for the effect ofa restriction on its transfer if that restriction isalready included in the other inputs to the fair valuemeasurement.The guidance for measuring the fair value of anentity’s own equity instruments is consistent withthat for measuring liabilities.14|Fair Value Measurement | May 2011Fair Value Measurement | May 2011| 15A topic that was of particular interest for ﬁ nancial institutions was the measurement of ﬁ nancial instruments managed within a portfolio.The exposure draft proposed that the fair value measurement of a ﬁ nancial asset assumes that its fair value would be maximised by using the asset on a stand-alone basis (referred to in the exposure draft as the in-exchange valuation premise) because the market-based view of fair value assumes that there is no incremental value from holding a ﬁ nancial asset within a portfolio. The exposure draft also proposed an amendment to IAS 39 Financial Instruments: Recognition and Measurement, specifying that the unit of account for a ﬁ nancial instrument is the individual ﬁ nancial instrument at all levels of the fair value hierarchy (ie Levels 1, 2 and 3).US GAAP did not specify the valuation premise for ﬁ nancial assets.Measuring the fair value of ﬁ nancial instruments within a portfolioRespondents’ commentsThe proposal to require the fair value of a ﬁ nancialasset to be measured using the in-exchange valuation premise was generally not supported. Somerespondents believed that when combined with the proposed amendment to IAS 39 about the unit of account for ﬁ nancial instruments, the fair value of ﬁ nancial assets does not reﬂ ect that those assets are held within a portfolio, even when an entity manages its ﬁ nancial instruments on the basis of the entity’s net exposure, rather than its gross exposure, to market risks and credit risk. Those proposals were viewed as a major change in the practice of measuring the fair value of ﬁ nancial instruments.Respondents were concerned that the exposure draft proposed a separation in the valuation of ﬁ nancial instruments for ﬁ nancial reporting from the entity’s internal risk management practices. In addition, those respondents were concerned about the systems changes that would be necessary to effect the change.To preserve the relationship between ﬁ nancialreporting and risk management, some respondents asked whether they would be able to apply the proposed bid-ask spread guidance to each of the individual instruments so that the sum of the fair values of the individual instruments equals the value of the net position.Other respondents suggested that we should continue to allow the existing practice under IAS 39 and IFRS 9, which stated:When an entity has assets and liabilities with offsetting market risks, it may usemid-market prices as a basis for establishing fair values for the offsetting risk positions and apply the bid or asking price to the net open position as appropriate.As with other aspects of the proposals in the exposure draft, respondents asked us to work withthe FASB to ensure that IFRSs and US GAAP have the same requirements for measuring the fair value of ﬁ nancial instruments.Our responseBecause fair value is a market-based measurement, the fair value of a ﬁ nancial asset reﬂ ects any beneﬁ ts that market participants would derive from holding that asset within a diversiﬁ ed portfolio. Therefore,an entity would derive no incremental value from holding the asset within a portfolio. IFRSs andUS GAAP did not explicitly address how the current measurement requirements for ﬁ nancial instruments managed within a portfolio meet the objective ofa fair value measurement. For example, entities typically do not manage their exposure to market risks and credit risk by selling a ﬁ nancial asset or transferring a ﬁ nancial liability (eg by unwindinga transaction). Rather, they manage their risk exposure by entering into a transaction for another ﬁ nancial instrument (or instruments) that would result in an offsetting position in the same risk.In addition, an entity’s net risk exposure is a function of the other ﬁ nancial instruments held by the entity and of the entity’s risk preferences (both of which are entity-speciﬁ c decisions and, thus, do not form part of a fair value measurement). As a result, we decided to permit an exception to therequirements for measuring fair value that allows anentity to measure the fair value of a group of ﬁ nancialassets and ﬁ nancial liabilities on the basis of the pricethat would be received to sell a net long position(ie an asset) for a particular risk exposure or totransfer a net short position (ie a liability) for aparticular risk exposure in an orderly transactionbetween market participants at the measurementdate. That exception applies to ﬁ nancial instrumentsmeasured at fair value on a recurring basis in thestatement of ﬁ nancial position.To be able to use that exception, an entity needsto provide evidence that it manages its ﬁ nancialinstruments on the basis of its net exposure to thoserisks on a consistent basis, the market risks beingoffset must be substantially the same and, in the caseof credit risk, there must be an arrangement with thecounterparty that mitigates credit risk exposure in theevent of default.16|Fair Value Measurement | May 2011Fair Value Measurement | May 2011| 17The exposure draft did not address premiums and discounts in measuring fair value. However, it proposed amending IAS 39 to specify that at all levels of the fair value hierarchy the unit of account for a ﬁ nancial instrument is the individual ﬁ nancial instrument. The effect of that proposal would be the prohibition of a premium or a discount related to the size of an entity’s holding of ﬁ nancial instruments.Premiums and discountsRespondents’ commentsMost respondents did not support the proposal.In their view, entities do not typically exit a position on an individual instrument basis (eg by entering into a transaction to sell a single ordinary share). Furthermore, they think a fair value measurement should reﬂ ect the fair value of the entity’s holding, not of an individual instrument within that holding. As a result, thoserespondents thought that the prohibition of a blockage factor, which is the term used in US GAAP to describe an adjustment related to the size of an entity’s holding relative to the trading volume of the underlying assets or liabilities making up that holding, would not reﬂ ect the economic position of an entity with such a holding. The FASB received similar comments when developing SFAS 157.In addition, respondents had different interpretations about what the term blockage factor means. Some respondents thought we intended to prohibit any premium or discount (such as a control premium or a discount for lack of marketability) even when market participants would take into account that premium or discount when pricing the asset or liability at a particular unit of account level.Our responseWe concluded that it is necessary:• to clarify that a fair value measurement incorporates premiums or discounts when they reﬂ ect acharacteristic of the asset or liability that market participants would take into account in a transaction for the asset or liability.• to prohibit the application of a blockage factor (which IFRS 13 describes as an adjustment to the quoted price of an asset or a liability because the market’s normal daily trading volume is not sufﬁ cient to absorb the quantity held by the entity). In our view, that prohibition is appropriate because it is a discount that reﬂ ects size as a characteristic of the entity’s holding rather than as a characteristic of the asset or liability being measured at fair value.。

Predicting Material Accounting Misstatements

Predicting Material Accounting Misstatements* PATRICIA M.DECHOW,University of California,BerkeleyWEILI GE,University of WashingtonCHAD RSON,Washington University in St.LouisRICHARD G.SLOAN,University of California,Berkeley1.IntroductionWhat causes managers to misstate theirﬁnancial statements?How best can investors,auditors,ﬁnancial analysts,and regulators detect misstatements? Addressing these questions is of critical importance to the efﬁcient function-ing of capital markets.For an investor it can lead to improved returns,for an auditor it can mean avoiding costly litigation,for an analyst it can mean avoiding a damaged reputation,and for a regulator it can lead to enhanced investor protection and fewer investment debacles.Our research has two objectives.First,we develop a comprehensive database ofﬁnancial misstate-ments.Our objective is to describe this database and make it broadly available to other researchers to promote research on earnings misstate-ments.1Second,we analyze theﬁnancial characteristics of misstatingﬁrms and develop a model to predict misstatements.The output of this analysis is *Accepted by Michael Welker.We appreciate the comments of the workshop participants at the University of Michigan,the UBCOW Conference at the University of Washington, New York University2007Summer Camp,University of California,Irvine and University of Colorado at Boulder,Columbia University,University of Oregon,the Penn State2008 Conference,University of California,Davis2008Conference,American Accounting Association meetings2007,FARS2008meetings,the University of NSW Ball and Brown Conference in Sydney2008,and the2009George Mason University Conference on Corpo-rate Governance and Fraud Prevention.We thank Michael Welker(associate editor)and two anonymous referees for their helpful comments.We thank Ray Ball,Sid Balachandran, Sandra Chamberlain,Ilia Dichev,Bjorn Jorgensen,Bill Kinney,Carol Marquardt,Mort Pincus,and Charles Shi for their comments and Seungmin Chee for research assistance.We would like to thank the Research Advisory Board established by Deloitte&Touche USA LLP,Ernst&Young LLP,KPMG LLP and PricewaterhouseCoopers LLP for the funding for this project.However,the views expressed in this article and its content are ours alone and not those of Deloitte&Touche USA LLP,Ernst&Young LLP,KPMG LLP,or PricewaterhouseCoopers LLP.Special thanks go to Roslyn Hooten for administering the funding relationship.This paper is dedicated to the memory of our colleague,friend,and research team member,Nader Hafzalla,who was a joy to all who knew him.1.For more information on the data,please e-mail CFRMdata@.Contemporary Accounting Research Vol.28No.1(Spring2011)pp.17–82ÓCAAAdoi:10.1111/j.1911-3846.2010.01041.x18Contemporary Accounting Researcha scaled probability(F-score)that can be used as a redﬂag or signal of the likelihood of earnings management or misstatement.We compile our database through a detailed examination ofﬁrms that have been subject to enforcement actions by the U.S.Securities and Exchange Commission(SEC)for allegedly misstating theirﬁnancial state-ments.Since1982,the SEC has issued Accounting and Auditing Enforcement Releases(AAERs)during or at the conclusion of an investigation against a company,an auditor,or an ofﬁcer for alleged accounting and⁄or auditing misconduct.These releases provide varying degrees of detail on the nature of the misconduct,the individuals and entities involved,and the effect on theﬁnancial statements.We examine the2,190AAERs released between 1982and2005.Our examination identiﬁes676uniqueﬁrms that have misstated at least one of their quarterly or annualﬁnancial statements.2 Using AAERs as a source to investigate characteristics ofﬁrms that manipulateﬁnancial statements has both advantages and disadvantages. The SEC has a limited budget,so it selectsﬁrms for enforcement action where there is strong evidence of manipulation.Firms selected often have already admitted a‘‘mistake’’by restating earnings or having large write-offs(e.g.,Enron or Xerox);otherﬁrms have already been identiﬁed by the press or analysts as having misstated earnings(see Miller2006);in addition, insider whistleblowers often reveal problems directly to the SEC.Therefore, one advantage of the AAER sample is that researchers can have a high level of conﬁdence that the SEC has identiﬁed manipulatingﬁrms(the Type I error rate is low).However,one disadvantage is that manyﬁrms that manipulate earnings are likely to go unidentiﬁed,and a second disadvantage is that there could be selection biases in cases pursued by the SEC.For example,the SEC may be more likely to pursue cases where stock perfor-mance declines rapidly after the manipulation is revealed,because the iden-tiﬁable losses to investors are greater.Selection biases may limit the generalizability of our results to other settings.It is worth noting,however, that problems with selection bias exist for other samples of manipulators identiﬁed by an external source—for example,shareholder litigationﬁrms, Sarbanes-Oxley Act(SOX)internal control violationﬁrms,or restatement ﬁrms.3Bias concerns also exist for discretionary accrual measures(Dechow, Sloan,and Sweeney1995).Thus selection bias is a general concern when analyzing the determinants of earnings manipulation and is not unique to AAERﬁrms.2.Throughout the paper we use the terms earnings management,manipulation,and mis-statement interchangeably.Although fraud is often implied by the SEC’s allegations,we use the term misstatement becauseﬁrms and managers typically do not admit or deny guilt with respect to the SEC allegations.3.Shareholder lawsuitﬁrms are biased towardﬁrms that have had large stock pricedeclines;SOX internal violationﬁrms are biased toward youngerﬁrms with less devel-oped accounting systems;and restatementﬁrms are biased towardﬁrms that have madea mistake that is not necessarily intentional.CAR Vol.28No.1(Spring2011)Predicting Material Accounting Misstatements19 In our tests we focus on variables that can be easily measured from theﬁnancial statements because we want our analysis to be applicable in most settings facing investors,regulators,or auditors.Our tests focus only on AAERﬁrm-years that have overstated earnings.We examine(i)accrual qual-ity,(ii)ﬁnancial performance,(iii)nonﬁnancial measures,(iv)off-balance-sheet activities,and(v)market-based measures for identifying misstatements.We investigate several measures of accrual quality.We examine working capital accruals and the broader measure of accruals that incorporates long-term net operating assets(Richardson,Sloan,Soliman,and Tuna2005).We provide an analysis of two speciﬁc accruals,changes in receivables and inventory.These accounts have direct links to revenue recognition and cost of goods sold,both of which impact gross proﬁt,a key performance metric. We measure the percentage of‘‘soft’’assets on the balance sheet(deﬁned as the percentage of assets that are neither cash nor property,plant,and equipment(PP&E).We predict that the more assets on the balance sheet that are subject to changes in assumptions and forecasts,the greater the manager’sﬂexibility to manage short-term earnings(e.g.,Barton and Simko 2002;Richardson et al.2005).Weﬁnd that all measures of accrual quality are unusually high in misstating years relative to the broad population of ﬁrms.We alsoﬁnd that the percentage of soft assets is high,which suggests that manipulatingﬁrms have more ability to change and adjust assumptions to inﬂuence short-term earnings.In time-series tests that focus only on misstatingﬁrms,weﬁnd that the reversal of accruals is particularly important for detecting the misstatement. Weﬁnd that,in the years prior to the manipulation,all accrual measures are unusually high and in fact are not signiﬁcantly different from those of manip-ulation years.There are two explanations for thisﬁnding.First,managers are likely to utilize theﬂexibility within generally accepted accounting principles (GAAP)to report higher accruals and earnings before resorting to the aggres-sive manipulation identiﬁed by the SEC.Therefore,growing accruals in ear-lier years is consistent with‘‘within GAAP’’earnings management.Second, the positive accruals in earlier years could reﬂect an overinvestment problem. Managers in misstatingﬁrms could be relaxing credit policies,building up inventory andﬁxed asset capacity in anticipation of future growth.When that growth is not realized,managers then resort to the manipulation identiﬁed by the SEC.The two explanations are not mutually exclusive,because a manager who is optimistic and overinvesting is also likely to be optimistic in terms of assumptions and forecasts that relate to asset values and earnings.We examine various models of discretionary accruals developed in prior accounting research including the cross-sectional modiﬁed Jones model (Dechow et al.1995;DeFond and Jiambalvo1994),the performance-matched discretionary accruals model(Kothari,Leone,and Wasley2005), and a signed version of the earnings quality metric developed by Dechow and Dichev(2002).Our results indicate that the residuals from the modiﬁed Jones model and the performance-matched Jones model have less power toCAR Vol.28No.1(Spring2011)20Contemporary Accounting Researchidentify manipulation than unadjusted accrual measures(i.e.,working capi-tal accruals and the broader measure of accruals)or the signed Dechow and Dichev model.This suggests that conventional approaches of control-ling for industry and performance induce considerable estimation error into the estimation of discretionary accruals.We examine whether the manipulations occur to hide diminishingﬁrm performance.Weﬁnd that returns on assets are generally declining;how-ever,contrary to our initial expectations,weﬁnd that cash sales are increas-ing during misstatement periods.We failed to anticipate the cash sales result because we expectedﬁrms to boost sales by overstating credit sales. There are two explanations for the unexpected cash sale result.First,mis-statingﬁrms tend to be growing their capital bases and increasing the scale of their business operations.The greater scale of operations should lead to increases in both cash and credit sales.Second,an inspection of the AAERs reveals that manyﬁrms misstate sales through transaction management—for example,encouraging sales to customers with return provisions that vio-late the deﬁnition of a sale,selling goods to related parties,or forcing goods onto customers at the end of the quarter.Weﬁnd that one nonﬁnancial measure,abnormal reductions in the num-ber of employees,is useful in detecting misstatements.This measure is new to the literature and is measured as year-over-year percentage change in employee headcount less year-over-year percentage change in total assets. This result can be interpreted in two ways.First,reductions in the number of employees are likely to occur when there is declining demand for aﬁrm’s product.In addition,cutting employees directly improves short-run earnings performance by lowering wage expenses.Second,if physical assets and employees are complements,then a decrease in employees relative to total assets could signal overstated asset balances.Our examination of off-balance-sheet information focuses on the exis-tence and use of operating leases and the expected return assumption on plan assets for deﬁned beneﬁt pension plans.Operating leases can be used to front-load earnings and reduce reported debt.Weﬁnd that the use of operating leases is unusually high during misstatementﬁrm-years.In addi-tion,moreﬁrms begin leasing in manipulation years(relative to earlier years).We alsoﬁnd that misstatingﬁrms have higher expected returns on their pension plan assets than otherﬁrms.The effect of higher expected return assumptions is to reduce reported pension expense.The results for leases and pensions are consistent with misstatingﬁrms exhausting‘‘legal’’earnings management options before resorting to more aggressiveﬁnancial misstatements.Ourﬁnal set of variables relates to stock and debt market incentives. Dechow et al.(1995)suggest that market incentives are an important reason for engaging in earnings management.Teoh,Welch,and Wong(1998)and Rangan(1998)provide corroborating evidence that accruals are unusually high at the time of equity issuances.However,the evidence in Beneish CAR Vol.28No.1(Spring2011)Predicting Material Accounting Misstatements21 1999b suggests that leverage and stock issuances do not motivate misstate-ments.Therefore,revisiting this question using our more comprehensive data is warranted.Weﬁnd that the comparison group is critical for evaluat-ing whether raisingﬁnancing is a motivation for the misstatement.Inconsis-tent with Beneish,weﬁnd that misstatingﬁrms are actively raising ﬁnancing in misstating years relative to the broad population ofﬁrms. However,consistent with Beneish,weﬁnd no signiﬁcant difference in the extent ofﬁnancing when we compare earlier years to manipulation years for the same AAERﬁrm.These results can be reconciled by the fact that weﬁnd misstatingﬁrms are actively raisingﬁnancing before and during the manipulation period.Thus,one interpretation of theseﬁndings is that man-agers of misstatingﬁrms are concerned with obtainingﬁnancing and this motivates earnings management in earlier years,as well as the more aggres-sive techniques identiﬁed by the SEC in misstating years.Also consistent with Beneish,we do notﬁnd evidence that misstatingﬁrms tend to have higherﬁnancial leverage than nonmisstatingﬁrms.We examine the growth expectations embedded in misstatingﬁrms’stock market valuations.Weﬁnd that the price-earnings and market-to-book ratios are unusually high for misstatementﬁrms compared to other ﬁrms,suggesting that investors are optimistic about the future growth opportunities of theseﬁrms.We alsoﬁnd that the misstatingﬁrms have unusually strong stock return performance in the years prior to misstate-ment.This is consistent with managers engaging in aggressive techniques in misstating years in the hopes of avoiding disappointing investors and losing their high valuations(Skinner and Sloan2002).Ourﬁnal tests aim at developing a prediction model that can synthesize theﬁnancial statement variables that we examine and provide insights into which variables are relatively more useful for detecting misstatements.The model is built in stages based on the ease of obtaining the information and compares the characteristics of misstatingﬁrm-years to other publicﬁrms. Model1includes variables that are obtained from the primaryﬁnancial statements.These variables include accrual quality andﬁrm performance. Model2adds off-balance-sheet and nonﬁnancial measures.Model3adds market-related variables.The output of these models is a scaled logistic probability for eachﬁrm-year that we term the F-score.We show that,while only20percent of the publicﬁrms have an F-score greater than1.4,over50percent of misstatingﬁrms have F-scores of1.4or higher.We also investigate the time-series pattern of F-scores for misstating ﬁrms.We show that average F-scores for misstatingﬁrms increase for up to three years prior to the misstatement,but decline rapidly to more normal levels in the years following the misstatement.This is consistent with the F-score identifying within-GAAP earnings management as well as the more aggressive techniques identiﬁed by the SEC.We discuss interpretation issues concerning Type I and Type II errors related to the F-score and provide marginal analysis and sensitivity analysis showing that variation in theCAR Vol.28No.1(Spring2011)22Contemporary Accounting ResearchF-score is not driven by one speciﬁc variable.We also conduct several robustness tests that conﬁrm the stability of the variables selected for our models,our coefﬁcient estimates,and the predictive ability of the F-score over time.The remainder of the paper is organized as follows.Section2reviews previous research on this topic.Section3describes database construction and research design.Section4presents our analysis of misstatementﬁrms and develops our misstatement-prediction model.Section5concludes.2.Previous literatureUnderstanding the types ofﬁrms that will misstateﬁnancial statements is an extensive area of research.We brieﬂy discuss some of the keyﬁndings but do not attempt to document all literature examining characteristics of AAERﬁrms.Dechow,Ge,and Schrand(2010)provide a comprehensive review of this literature.Early work by Feroz,Park,and Pastena1991examines224AAERs issued between April1982and April1989covering188ﬁrms,of which58 have stock price information.Feroz et al.document that receivables and inventory are commonly misstated.Two pioneering papers analyzing mis-statingﬁrms are Beneish1997and Beneish1999a.Beneish(1997)analyzes 363AAERs covering49ﬁrms and a further15ﬁrms whose accounting was questioned by the news media between1987and1993.The64ﬁrms are classiﬁed as manipulators.He creates a separate sample ofﬁrms using the modiﬁed Jones model to selectﬁrms with high accruals that he terms ‘‘aggressive accruers’’.His objective is to distinguish the manipulators from the aggressive accruers.Beneish(1997)ﬁnds that accruals,day’s sales in receivables,and prior performance are important for explaining the differ-ences between the two groups.Beneish(1999a)matches the sample of manipulators to2,332COMPUSTAT nonmanipulators by two-digit SIC industry and year for which theﬁnancial statement data used in the model were available.For seven of the eightﬁnancial statement ratios that he ana-lyzes,he calculates an index,with higher index values indicating a higher likelihood of an earnings overstatement.Beneish shows that the day’s sales in receivables index,gross margin index,asset quality index,sales growth index,and accruals(measured as the change in noncash working capital plus depreciation)are important.He provides a probit model and analyzes the probability cutoffs that minimize the expected costs of misstatements.Our research builds on and is complementary to Beneish(1997,1999a). We take a different perspective from Beneish that leads us to make a num-ber of different choices.However,such differences should not be viewed as a critique of his approach;rather,they stem from our objectives.One of our objectives is to develop a measure that can be directly calculated from theﬁnancial statements.Therefore,we do not use indexes for any of our variables.A second objective is to enable researchers and practitioners to calculate an F-score for a randomﬁrm and to easily assess the probability CAR Vol.28No.1(Spring2011)Predicting Material Accounting Misstatements23 of misstatement.Therefore,we do not match AAERﬁrms to a control group by industry or size.Matching by industry and size provides informa-tion on whether a variable is signiﬁcantly different relative to a controlﬁrm. However,it is more difﬁcult when matching to determine Type I and Type II error rates that users will face in an unconditional setting.Models could be developed for individual industries and size categories.We choose not to do this because it would add greatly to the complexity of our analysis and the presentation of our results.A third objective is to evaluate the useful-ness ofﬁnancial statement information beyond that contained in the pri-maryﬁnancial statements;therefore we include other information disclosed in the10-K either in item1(discussion of the business),item5(stock price information),or the footnotes.Concurrent research provides additional insights into variables that are useful for detecting misstatements.Ettredge,Sun,Lee,and Anandara-jan(2006)examine169AAERﬁrms matched byﬁrm size,industry,and whether theﬁrm reported a loss.Theyﬁnd that deferred taxes can be use-ful for predicting misstatements,along with auditor change,market-to-book,revenue growth,and whether theﬁrm is an over-the-counterﬁrm. Brazel,Jones,and Zimbelman(2009)examine whether several nonﬁnancial measures(e.g.,number of patents,employees,and products)can be used to predict misstatement in50AAERﬁrms.Theyﬁnd that growth rates betweenﬁnancial and nonﬁnancial variables are signiﬁcantly different for AAERﬁrms.Bayley and Taylor(2007)study129AAERﬁrms and a matched sample based on industry,ﬁrm size,and time period.Theyﬁnd that total accruals are better than various measures of unexpected accruals in identifying material accounting misstatements.In addition,theyﬁnd that variousﬁnancial statement ratio indices are incrementally useful.They conclude that future earnings management research should move away from further reﬁnements of discretionary accrual models and instead con-sider supplementing accruals with otherﬁnancial statement ratios.We agree with Bayley and Taylor and view our work as moving in the direc-tion that they recommend.There has also been work using AAERﬁrms to examine the role of cor-porate governance and incentive compensation in encouraging earnings manipulation(see,e.g.,Dechow,Sloan,and Sweeney1996;Beasley1996; Farber2005;Skousen and Wright2006;for a summary,Dechow et al. 2010).We chose not to investigate the role of governance variables and compensation because these variables are available for only limited samples or must be hand collected.Therefore,adding these variables would have limited our analysis to a smaller sample with various biases in terms of data availability.However,a useful avenue for future research is to analyze the role of governance,compensation,insider trading,short selling,incentives to meet and beat analyst forecasts,and so on and to determine the relative importance of these variables overﬁnancial statement information in detect-ing overstatements of earnings.CAR Vol.28No.1(Spring2011)24Contemporary Accounting Research3.Data and sample formationSampleThe objective of our data collection efforts is to construct a comprehensive sample of material and economically signiﬁcant accounting misstatements involving both GAAP violations and the allegation that the misstatement was made with the intent of misleading investors.Thus we focus our data collection on the SEC’s series of published AAERs.4The SEC takes enforcement actions againstﬁrms,managers,auditors, and other parties involved in violations of SEC and federal rules.At the completion of a signiﬁcant investigation involving accounting and auditing issues,the SEC issues an AAER.The SEC identiﬁesﬁrms for review through anonymous tips and news reports.Another source is the volun-tary restatement of theﬁnancial results by theﬁrm itself,because restate-ments are viewed as a redﬂag by the SEC.The SEC also states that it reviews about one-third of public companies’ﬁnancial statements each year and checks for compliance with GAAP.If SEC ofﬁcials believe that reported numbers are inconsistent with GAAP,then the SEC can initiate informal inquiries and solicit additional information.If the SEC is satis-ﬁed after such informal inquiries,then it will drop the case.However, if the SEC believes that one or more parties violated securities laws,then the SEC can take further steps,including enforcement actions requiring theﬁrm to change its accounting methods,restateﬁnancial statements, and pay damages.There are a number of conceivable alternative sources for identifying accounting misstatements.They are discussed brieﬂy below,along with our reasons for not pursuing these alternatives.1.The Government Accountability Ofﬁce(GAO)Financial StatementRestatement Database.This database consists of approximately2,309 restatements between January1997and September2005.This database was constructed through a Lexis-Nexis text search of press releases and other media coverage based on variations of the word‘‘restate’’.There is some overlap between the AAERﬁrms and the GAO restatementﬁrms because(a)the SEC often requiresﬁrms to restate theirﬁnancials as part of a settlement and(b)restatements often trigger SEC investigations.The GAO database covers a relatively small time period but consists ofa relatively large number of restatements.The reason for the large4.The AAER series began on May17,1982,with the SEC’s issuance of AAER No.1.The SEC states in theﬁrst AAER that the series would include‘‘future...enforcement actions involving accountants’’and‘‘enable interested persons to easily distinguish enforcement releases involving accountants from other Commission releases’’(AAER No1).Although the AAERs often directly involve accountants,the AAER series also includes enforcement actions against nonaccountant employees that result from account-ing misstatements and manipulations.CAR Vol.28No.1(Spring2011)Predicting Material Accounting Misstatements25 number of restatements is that the GAO database includes all restatements relating to accounting irregularities regardless of managerial intent,materiality,and economic signiﬁcance.Consequently,it includes a large number of economically insigniﬁcant restatements.In addition, the results in Plumlee and Yohn2010suggest that many restatements are a consequence of misinterpreting accounting rules rather than intentional misstatements.Another shortcoming of the GAO database is that it speciﬁes only the year in which the restatement was identiﬁed in the press and not the reporting periods that were required to be restated.52.Stanford Law Database on Shareholder Lawsuits.Shareholder lawsuitstypically result from material intentional misstatements.However,share-holder lawsuits can also arise for a number of other reasons that are unrelated toﬁnancial misstatements.Shareholder lawsuits alleging mis-statements are also very common after a stock has experienced a precipi-tous price decline,even when there is no clear evidence supporting the allegation.In contrast,the SEC issues an enforcement action only when it has established intent or gross negligence on the part of management in making the misstatement.Using the SEC’s AAERs as a sample of misstatementﬁrms has several advantages relative to other potential samples.First,the use of AAERs as a proxy for manipulation is a straightforward and consistent methodology.This methodology avoids potential biases induced in samples based on researchers’individual classiﬁcation schemes and can be easily replicated by other researchers.Second,AAERs are also likely to capture a group of economically signiﬁcant manipulations as the SEC has limited resources and likely pursues the most important cases.Relative to other methods of identifying a sample ofﬁrms with managed earnings,such as the modiﬁed Jones abnormal accruals model,using misstatements identiﬁed in AAERs as an indicator is expected to generate a much lower Type I error.Despite the advantages of using AAERs to identify accounting misstate-ments,there are caveats.We can investigate only thoseﬁrms identiﬁed by the SEC as having misstated earnings.The inclusion of the misstatements that are not identiﬁed by the SEC in our control sample is likely to reduce the predictive ability of our model.Therefore,our analyses can be inter-preted as joint tests of engaging in an accounting misstatement and receiv-ing an enforcement action from the SEC.If it is assumed that the SEC selection criteria are highly correlated with our prediction variables,then another criticism is that identiﬁed variables could reﬂect SEC selection. However,as noted above,the SEC identiﬁesﬁrms from a variety of sources 5.For example,while Xerox is included in the GAO database in2002,the restatements inquestion relate to Xerox’sﬁnancial statements for1997,1998,1999,2000,and2001.CAR Vol.28No.1(Spring2011)26Contemporary Accounting Researchand not just from its own internal reviews,and many cases are brought to its attention because theﬁrm itself either restates or takes a large write-off. Thus,selection choices are unlikely to be a complete explanation for our ﬁndings.In addition,from aﬁrm’s perspective,being subject to an SEC enforcement action brings signiﬁcantly negative capital market conse-quences(Dechow et al.1996;Karpoff,Lee,and Martin2008).Therefore, avoiding these characteristics could be useful and thus affectﬁrm and market behavior.Data setsWe catalog all the AAERs from AAER1through AAER2261spanning May17th,1982through June10th,2005.We next identify allﬁrms that are alleged to have violated GAAP by at least one of these AAERs(we describe this procedure in more detail in the next section).We then create three data ﬁles:the Detail,Annual,and Quarterlyﬁles.The Detailﬁle contains all AAER numbers pertaining to eachﬁrm,ﬁrm identiﬁers,a description of the reason the AAER was issued,and indicator variables categorizing which balance-sheet and income-statement accounts were identiﬁed in the AAER as being affected by the violation.There is only one observation perﬁrm in the Detailﬁle.The Annual and Quarterlyﬁles are compiled from the Detail ﬁle and are formatted by reporting period so that each quarter or year affected by the violation is a separate observation.The Appendix lists the variable names and description for eachﬁle in the database.Data collectionThe original AAERs are the starting point for collecting data.Copies of the AAERs are obtained from the SEC website and the LexisNexis database. Each AAER is separately examined to identify whether it involves an alleged GAAP violation.In cases where a GAAP violation is involved,the reporting periods that were alleged to be misstated are identiﬁed.The data coding was completed in three phases.In theﬁrst phase,all releases were read in order to obtain the company name and period(s)in which the violation took place.The AAERs are simply listed chronologi-cally based on the progress of SEC investigations.To facilitate our empiri-cal analysis,we record misstatements byﬁrm and link them back to their underlying AAERs in the detailﬁle.Note that multiple AAERs may pertain to a single set of restatements at a singleﬁrm.Panel A of Table1 indicates that we are unable to locate30of the2,261AAERs,because they were either missing or not released by the SEC.A further41AAERs relate to auditors or other parties and do not mention speciﬁc company names. This leaves us with2,190AAERs mentioning a company name.Panel B of Table1reports that,in the2,190AAERs,the SEC takes action against2,614different parties.Note that one AAER can be issued against multiple parties.In49.2percent(1,077)of the cases the party was an ofﬁcer of the company(e.g.,chief executive ofﬁcer(CEO)or chief CAR Vol.28No.1(Spring2011)。

会计商务英语试题及答案

会计商务英语试题及答案一、单项选择题（每题2分，共20分）1. Which of the following is not a function of accounting?A. Record-keepingB. Decision-makingC. Financial reportingD. Market research2. The process of identifying, measuring, and communicating economic information is known as:A. AuditingB. BudgetingC. AccountingD. Taxation3. What is the term used to describe the systematic and periodic recording of all business transactions?A. BookkeepingB. AccountingC. ReportingD. Analysis4. Which of the following is not a component of the financial statements?A. Balance sheetB. Income statementC. Cash flow statementD. Marketing plan5. The principle that requires companies to match revenues and expenses in the same accounting period is known as:A. Accrual basis accountingB. Cash basis accountingC. Matching principleD. Revenue recognition principle6. What is the term for the difference between assets and liabilities on a company's balance sheet?A. EquityB. ProfitC. LossD. Capital7. The process of adjusting account balances to ensure they are accurate at the end of an accounting period is called:A. Closing the booksB. Adjusting entriesC. AuditingD. Budgeting8. Which of the following is not a type of intangible asset?A. TrademarksB. PatentsC. GoodwillD. Inventory9. The statement that shows the results of a company's operations over a period of time is:A. Balance sheetC. Cash flow statementD. Statement of changes in equity10. The process of verifying the accuracy of financialrecords is known as:A. AccountingB. AuditingC. BookkeepingD. Taxation二、多项选择题（每题3分，共15分）1. Which of the following are considered current assets?A. CashB. Accounts receivableC. LandD. Inventory2. The main components of a company's liabilities include:A. Accounts payableB. Long-term debtC. EquityD. Deferred revenue3. The following are examples of accounting principles except:A. Going concernB. ConsistencyC. MaterialityD. Market research4. Which of the following are considered as expenses in theA. Cost of goods soldB. Salaries and wagesC. Dividends paidD. Depreciation5. The main purposes of financial reporting include:A. Assisting in decision-makingB. Compliance with regulationsC. Enhancing company imageD. Facilitating communication with stakeholders三、填空题（每题2分，共20分）1. The accounting equation is expressed as: Assets = Liabilities + ________.2. The term used to describe the increase in the value of an asset or a decrease in the value of a liability is ________.3. The process of preparing financial statements at the end of an accounting period is known as ________.4. The statement that shows the changes in cash and cash equivalents during a period is called the ________.5. The principle that requires companies to provide information that is clear and understandable to users is known as the ________ principle.6. The term used to describe the decrease in the value of an asset due to use, wear and tear, or obsolescence is ________.7. The process of determining the cost of goods sold is based on the ________ of inventory.8. The term used to describe the allocation of costs over the useful life of an asset is ________.9. The process of adjusting the accounts to reflect theactual financial position of a company is called ________.10. The term used to describe the difference between the purchase price and the fair value of an asset is ________.四、简答题（每题10分，共40分）1. Explain the difference between the accrual basis and cash basis of accounting.2. Describe the role of the balance sheet in financial reporting.3. What are the main objectives of an audit?4. Discuss the importance of internal controls in accounting and finance.五、案例分析题（共15分）A company has the following transactions during the month of January:- Received cash from customers for goods sold: $10,000- Paid suppliers for inventory purchased: $6,000- Paid salaries to employees: $3,000- Received a loan from a bank: $5,000- Paid rent for the office: $2,000Based on the above transactions, prepare a simple income statement and balance sheet for the month of January.答案：一、单项选择题1. D2. C3. A4. D 5。

粘弹性功能梯度有限元法使用对应原理

Viscoelastic Functionally Graded Finite-Element MethodUsing Correspondence PrincipleEshan V.Dave,S.M.ASCE1;Glaucio H.Paulino,Ph.D.,M.ASCE2;andWilliam G.Buttlar,Ph.D.,P.E.,A.M.ASCE3Abstract:Capability to effectively discretize a problem domain makes theﬁnite-element method an attractive simulation technique for modeling complicated boundary value problems such as asphalt concrete pavements with material non-homogeneities.Specialized “graded elements”have been shown to provide an efﬁcient and accurate tool for the simulation of functionally graded materials.Most of the previous research on numerical simulation of functionally graded materials has been limited to elastic material behavior.Thus,the current work focuses onﬁnite-element analysis of functionally graded viscoelastic materials.The analysis is performed using the elastic-viscoelastic correspondence principle,and viscoelastic material gradation is accounted for within the elements by means of the generalized iso-parametric formulation.This paper emphasizes viscoelastic behavior of asphalt concrete pavements and several examples, ranging from veriﬁcation problems toﬁeld scale applications,are presented to demonstrate the features of the present approach.DOI:10.1061/͑ASCE͒MT.1943-5533.0000006CE Database subject headings:Viscoelasticity;Asphalt pavements;Concrete pavements;Finite-element method.Author keywords:Viscoelasticity;Functionally graded materials;Asphalt pavements;Finite-element method;Correspondence principle.IntroductionFunctionally Graded Materials͑FGMs͒are characterized by spa-tially varied microstructures created by nonuniform distributionsof the reinforcement phase with different properties,sizes andshapes,as well as,by interchanging the role of reinforcement andmatrix materials in a continuous manner͑Suresh and Mortensen1998͒.They are usually engineered to produce property gradientsaimed at optimizing structural response under different types ofloading conditions͑thermal,mechanical,electrical,optical,etc.͒͑Cavalcante et al.2007͒.These property gradients are produced in several ways,for example by gradual variation of the content ofone phase͑ceramic͒relative to another͑metallic͒,as used in ther-mal barrier coatings,or by using a sufﬁciently large number ofconstituent phases with different properties͑Miyamoto et al.1999͒.Designer viscoelastic FGMs͑VFGMs͒can be tailored tomeet design requirements such as viscoelastic columns subjectedto axial and thermal loads͑Hilton2005͒.Recently,Muliana ͑2009͒presented a micromechanical model for thermoviscoelastic behavior of FGMs.Apart from engineered or tailored FGMs,several civil engi-neering materials naturally exhibit graded material properties. Silva et al.͑2006͒have studied and simulated bamboo,which is a naturally occurring graded material.Apart from natural occur-rence,a variety of materials and structures exhibit nonhomoge-neous material distribution and constitutive property gradations as an outcome of manufacturing or construction practices,aging, different amount of exposure to deteriorating agents,etc.Asphalt concrete pavements are one such example,whereby aging and temperature variation yield continuously graded nonhomogeneous constitutive properties.The aging and temperature induced prop-erty gradients have been well documented by several researchers in theﬁeld of asphalt pavements͑Garrick1995;Mirza and Witc-zak1996;Apeagyei2006;Chiasson et al.2008͒.The current state-of-the-art in viscoelastic simulation of asphalt pavements is limited to either ignoring non-homogeneous property gradients ͑Kim and Buttlar2002;Saad et al.2006;Baek and Al-Qadi2006; Dave et al.2007͒or considering them through a layered ap-proach,for instance,the model used in the American Association of State Highway and Transportation Ofﬁcials͑AASHTO͒Mechanistic Empirical Pavement Design Guide͑MEPDG͒͑ARA Inc.,EC.2002͒.Signiﬁcant loss of accuracy from the use of the layered approach for elastic analysis of asphalt pavements has been demonstrated͑Buttlar et al.2006͒.Extensive research has been carried out to efﬁciently and ac-curately simulate functionally graded materials.For example, Cavalcante et al.͑2007͒,Zhang and Paulino͑2007͒,Arciniega and Reddy͑2007͒,and Song and Paulino͑2006͒have all reported onﬁnite-element simulations of FGMs.However,most of the previous research has been limited to elastic material behavior.A variety of civil engineering materials such as polymers,asphalt concrete,Portland cement concrete,etc.,exhibit signiﬁcant rate and history effects.Accurate simulation of these types of materi-als necessitates the use of viscoelastic constitutive models.1Postdoctoral Research Associate,Dept.of Civil and EnvironmentalEngineering,Univ.of Illinois at Urbana-Champaign,Urbana,IL61801͑corresponding author͒.2Donald Biggar Willett Professor of Engineering,Dept.of Civil andEnvironmental Engineering,Univ.of Illinois at Urbana-Champaign,Ur-bana,IL61801.3Professor and Narbey Khachaturian Faculty Scholar,Dept.of Civiland Environmental Engineering,Univ.of Illinois at Urbana-Champaign,Urbana,IL61801.Note.This manuscript was submitted on April17,2009;approved onOctober15,2009;published online on February5,2010.Discussion pe-riod open until June1,2011;separate discussions must be submitted forindividual papers.This paper is part of the Journal of Materials in CivilEngineering,V ol.23,No.1,January1,2011.©ASCE,ISSN0899-1561/2011/1-39–48/$25.00.JOURNAL OF MATERIALS IN CIVIL ENGINEERING©ASCE/JANUARY2011/39The current work presents aﬁnite element͑FE͒formulation tailored for analysis of viscoelastic FGMs and in particular,as-phalt concrete.Paulino and Jin͑2001͒have explored the elastic-viscoelastic correspondence principle͑CP͒in the context of FGMs.The CP-based formulation has been used in the current study in conjunction with the generalized iso-parametric formu-lation͑GIF͒by Kim and Paulino͑2002͒.This paper presents the details of theﬁnite-element formulation,veriﬁcation,and an as-phalt pavement simulation example.Apart from simulation of as-phalt pavements,the present approach could also be used for analysis of other engineering systems that exhibit graded vis-coelastic behavior.Examples of such systems include metals and metal composites at high temperatures͑Billotte et al.2006;Koric and Thomas2008͒;polymeric and plastic based systems that un-dergo oxidative and/or ultraviolet hardening͑Hollaender et al. 1995;Hale et al.1997͒and gradedﬁber reinforced cement and concrete structures.Other application areas for the graded vis-coelastic analysis include accurate simulation of the interfaces between viscoelastic materials such as the layer interface between different asphalt concrete lifts or simulations of viscoelastic glu-ing compounds used in the manufacture of layered composites ͑Diab and Wu2007͒.Functionally Graded Viscoelastic Finite-Element MethodThis section describes the formulation for the analysis of vis-coelastic functionally graded problems using FE framework and the elastic-viscoelastic CP.The initial portion of this section es-tablishes the basic viscoelastic constitutive relationships and the CP.The subsequent section provides the FE formulation using the GIF.Viscoelastic Constitutive RelationsThe basic stress-strain relationships for viscoelastic materials have been presented by,among other writers,Hilton͑1964͒and Christensen͑1982͒.The constitutive relationship for quasi-static, linear viscoelastic isotropic materials is given as␴ij͑x,t͒=2͵tЈ=−ϱtЈ=t G͓x,␰͑t͒−␰͑tЈ͔͒ͫ␧ij͑x,tЈ͒−13␦ij␧kkͬdtЈ+͵tЈ=−ϱtЈ=t K͓x,␰͑t͒−␰͑tЈ͔͒␦ij␧kk dtЈ͑1͒where␴ij=stresses;␧ij=strains at any location x.The parameters G and K=shear and bulk relaxation moduli;␦ij=Kronecker delta; and tЈ=integration variable.Subscripts͑i,j,k,l=1,2,3͒follow Einstein’s summation convention.The reduced time␰is related to real time t and temperature T through the time-temperature super-position principle␰͑t͒=͵0t a͓T͑tЈ͔͒dtЈ͑2͒For a nonhomogeneous viscoelastic body in quasi-static condi-tion,assume a boundary value problem with displacement u i on volume⍀u,traction P i on surface⍀␴and body force F i,the equilibrium and strain-displacement relationships͑for small de-formations͒are as shown in Eq.͑3͒␴ij,j+F i=0,␧ij=12͑u i,j+u j,i͒͑3͒respectively,where,u i=displacement and͑•͒,j=ץ͑•͒/ץx j.CP and Its Application to FGMsThe CP allows a viscoelastic solution to be readily obtained by simple substitution into an existing elastic solution,such as a beam in bending,etc.The concept of equivalency between trans-formed viscoelastic and elastic boundary value problems can be found in Read͑1950͒.This technique been extensively used by researchers to analyze variety of nonhomogeneous viscoelastic problems including,but not limited to,beam theory͑Hilton and Piechocki1962͒,ﬁnite-element analysis͑Hilton and Yi1993͒, and boundary element analysis͑Sladek et al.2006͒.The CP can be more clearly explained by means of an ex-ample.For a simple one-dimensional͑1D͒problem,the stress-strain relationship for viscoelastic material is given by convolution integral shown in Eq.͑4͒.␴͑t͒=͵0t E͑t−tЈ͒ץ␧͑tЈ͒ץtЈdtЈ͑4͒If one is interested in solving for the stress and material properties and imposed strain conditions are known,using the elastic-viscoelastic correspondence principle the convolution integral can be reduced to the following relationship using an integral trans-form such as the Laplace transform:␴˜͑s͒=sE˜͑s͒␧˜͑s͒͑5͒Notice that the above functional form is similar to that of the elastic problem,thus the analytical solution available for elastic problems can be directly applied to the viscoelastic problem.The transformed stress quantity,␴˜͑s͒is solved with known E˜͑s͒and ␧˜͑s͒.Inverse transformation of␴˜͑s͒provides the stress␴͑t͒.Mukherjee and Paulino͑2003͒have demonstrated limitations on the use of the correspondence principle in the context of func-tionally graded͑and nonhomogenous͒viscoelastic boundary value problems.Their work establishes the limitation on the func-tional form of the constitutive properties for successful and proper use of the CP.Using correspondence principle,one obtains the Laplace trans-form of the stress-strain relationship described in Eq.͑1͒as ␴˜ij͑x,s͒=2G˜͓x,␰˜͑s͔͒␧˜ij͑x,s͒+K˜͓x,␰˜͑s͔͒␦ij␧˜kk͑x,s͒͑6͒where s=transformation variable and the symbol tilde͑ϳ͒on top of the variables represents transformed variable.The Laplace transform of any function f͑t͒is given byL͓f͑t͔͒=f˜͑s͒=͵0ϱf͑t͒Exp͓−st͔dt͑7͒Equilibrium͓Eq.͑3͔͒for the boundary value problem in the trans-formed form becomes␴˜,j͑x,s͒=2G˜͑x,s͒␧˜,j d͑x,s͒+2G˜,j͑x,s͒␧˜d͑x,s͒+K˜͑x,s͒␧˜,j͑x,s͒+K˜,j͑x,s͒␧˜͑x,s͒͑8͒where superscript d indicates the deviatoric component of the quantities.Notice that the transformed equilibrium equation for a nonho-mogeneous viscoelastic problem has identical form as an elastic40/JOURNAL OF MATERIALS IN CIVIL ENGINEERING©ASCE/JANUARY2011nonhomogeneous boundary value problem.This forms the basis for using CP-based FEM for solving graded viscoelastic problems such as asphalt concrete pavements.The basic FE framework for solving elastic problems can be readily used through the use of CP,which makes it an attractive alternative when compared to more involved time integration schemes.However,note that due to the inapplicability of the CP for problems involving the use of the time-temperature superposition principle,the present analysis is applicable to problems with nontransient thermal conditions.In the context of pavement analysis,this makes the present proce-dure applicable to simulation of trafﬁc ͑tire ͒loading conditions for given aging levels.The present approach is not well-suited for thermal-cracking simulations,which require simulation of con-tinuously changing and nonuniform temperature conditions.FE FormulationThe variational principle for quasi-static linear viscoelastic mate-rials under isothermal conditions can be found in Gurtin ͑1963͒.Taylor et al.͑1970͒extended it for thermoviscoelastic boundary value problem͟=͵⍀u͵t Ј=−ϱt Ј=t ͵t Љ=−ϱt Љ=t −t Ј12C ijkl ͓x ,␰ijkl ͑t −t Љ͒−␰ijklЈ͑t Ј͔͒ϫץ␧ij ͑x ,t Ј͒ץt Јץ␧kl ͑x ,t Љ͒ץt Љdt Јdt Љd ⍀u−͵⍀u͵t Ј=−ϱt Ј=t ͵t Љ=−ϱt Љ=t −t ЈC ijkl ͓x ,␰ijkl ͑t −t Љ͒−␰ijklЈ͑t Ј͔͒ϫץ␧ij ء͑x ,t Ј͒ץt Јץ␧kl ء͑x ,t Љ͒ץt Љdt Јdt Љd ⍀u −͵⍀␴͵t Љ=−ϱt Љ=tP i ͑x ,t −t Љ͒ץu i ͑x ,t Љ͒ץt Љdt Љd ⍀␴=0͑9͒where ⍀u =volume of a body;⍀␴=surface on which tractions P iare prescribed;u i =displacements;C ijkl =space and time depen-dent material constitutive properties;␧ij =mechanical strains and ␧ij ء=thermal strains;while ␰ijkl =reduced time related to real time t and temperature T through time-temperature superposition prin-ciple of Eq.͑2͒.The ﬁrst variation provides the basis for the FE formulation␦͟=͵⍀u ͵t Ј=−ϱt Ј=t ͵t Љ=−ϱt Љ=t −t ЈͭC ijkl ͓x ,␰ijkl ͑t −t Љ͒−␰ijklЈ͑t Ј͔͒ץץt Ј͑␧ij ͑x ,t Ј͒−␧ij ء͑x ,t Ј͒͒ץ␦␧kl ͑x ,t Љ͒ץt Љͮdt Јdt Љd ⍀u−͵⍀␴͵t Љ=−ϱt Љ=tP i ͑x ,t −t Љ͒ץ␦u i ͑x ,t Љ͒ץt Љdt Љd ⍀␴=0͑10͒The element displacement vector u i is related to nodal displace-ment degrees of freedom q j through the shape functions N iju i ͑x ,t ͒=N ij ͑x ͒q j ͑t ͒͑11͒Differentiation of Eq.͑11͒yields the relationship between strain ␧i and nodal displacements q i through derivatives of shape func-tions B ij␧i ͑x ,t ͒=B ij ͑x ͒q j ͑t ͒͑12͒Eqs.͑10͒–͑12͒provide the equilibrium equation for each ﬁnite element͵tk ij ͓x ,␰͑t ͒−␰͑t Ј͔͒ץq j ͑t Ј͒ץt Јdt Ј=f i ͑x ,t ͒+f i th ͑x ,t ͒͑13͒where k ij =element stiffness matrix;f i =mechanical force vector;and f i th =thermal force vector,which are described as follows:k ij ͑x ,t ͒=͵⍀uB ik T ͑x ͒C kl ͓x ,␰͑t ͔͒B lj ͑x ͒d ⍀u ͑14͒f i ͑x ,t ͒=͵⍀␴N ij ͑x ͒P j ͑x ,t ͒d ⍀␴͑15͒f i th ͑x ,t ͒=͵⍀u͵−ϱtB ik ͑x ͒C kl ͓x ,␰͑t ͒−␰͑t Ј͔͒ץ␧l ء͑x ,t Ј͒ץt Јdt Јd ⍀u͑16͒␧l ء͑x ,t ͒=␣͑x ͒⌬T ͑x ,t ͒͑17͒where ␣=coefficient of thermal expansion and ⌬T =temperaturechange with respect to initial conditions.On assembly of the individual ﬁnite element contributions for the given problem domain,the global equilibrium equation can be obtained as͵tK ij ͓x ,␰͑t ͒−␰͑t Ј͔͒ץU j ͑t Ј͒ץt Јdt Ј=F i ͑x ,t ͒+F i th ͑x ,t ͒͑18͒where K ij =global stiffness matrix;U i =global displacement vec-tor;and F i and F i th =global mechanical and thermal force vectors respectively.The solution to the problem requires solving the con-volution shown above to determine nodal displacements.Hilton and Yi ͑1993͒have used the CP-based procedure for implementing the FE formulation.However,the previous re-search efforts were limited to use of conventional ﬁnite elements,while in the current paper graded ﬁnite elements have been used to efﬁciently and accurately capture the effects of material non-homogeneities.Graded elements have beneﬁt over conventional elements in context of simulating non-homogeneous isotropic and orthotropic materials ͑Paulino and Kim 2007͒.Kim and Paulino ͑2002͒proposed graded elements with the GIF,where the consti-tutive material properties are sampled at each nodal point and interpolated back to the Gauss-quadrature points ͑Gaussian inte-gration points ͒using isoparametric shape functions.This type of formulation allows for capturing the material nonhomogeneities within the elements unlike conventional elements which are ho-mogeneous in nature.The material properties,such as shear modulus,are interpolated asG Int.Point =͚i =1mG i N i ͑19͒where N i =shape functions;G i =shear modulus corresponding tonode i ;and m =number of nodal points in the element.JOURNAL OF MATERIALS IN CIVIL ENGINEERING ©ASCE /JANUARY 2011/41A series of weak patch tests for the graded elements have been previously established ͑Paulino and Kim 2007͒.This work dem-onstrated the existence of two length scales:͑1͒length scale as-sociated with element size,and ͑2͒length scale associated with material nonhomogeneity.Consideration of both length scales is necessary in order to ensure convergence.Other uses of graded elements include evaluation of stress-intensity factors in FGMs under mode I thermomechanical loading ͑Walters et al.2004͒,and dynamic analysis of graded beams ͑Zhang and Paulino 2007͒,which also illustrated the use of graded elements for simulation of interface between different material layers.In a recent study ͑Silva et al.2007͒graded elements were extended for multiphys-ics applications.Using the elastic-viscoelastic CP,the functionally graded vis-coelastic ﬁnite element problem could be deduced to have a func-tional form similar to that of elastic place transform of the global equilibrium shown in Eq.͑18͒isK ˜ij ͑x ,s ͒U ˜j ͑s ͒=F ˜i ͑x ,s ͒+F ˜i th ͑x ,s ͒͑20͒Notice that the Laplace transform of hereditary integral ͓Eq.͑18͔͒led to an algebraic relationship ͓Eq.͑23͔͒,this is major beneﬁt of using CP as the direct integration for solving hereditary integrals will have signiﬁcant computational cost.As discussed in a previ-ous section,the applicability of correspondence principle for vis-coelastic FGMs imposes limitations on the functional form of constitutive model.With this knowledge,it is possible to further customize the FE formulation for the generalized Maxwell model.Material constitutive properties for generalized Maxwell model is given asC ij ͑x ,t ͒=͚h =1n͓C ij ͑x ͔͒h Exp ͫ−t ͑␶ij ͒hͬ͑no sum ͒͑21͒where ͑C ij ͒h =elastic contributions ͑spring coefﬁcients ͒;͑␶ij ͒h=viscous contributions from individual Maxwell units,commonly called relaxation times;and n ϭnumber of Maxwell unit.Fig.1illustrates simpliﬁed 1D form of the generalized Max-well model represented in Eq.͑21͒.Notice that the generalized Maxwell model discussed herein follows the recommendations made by Mukherjee and Paulino ͑2003͒for ensuring success of the correspondence principle.For the generalized Maxwell model,the global stiffness matrix K of the system can be rewritten asK ij ͑x ,t ͒=K ij 0͑x ͒Exp ͩ−t ␶ijͪ=K ij 0͑x ͒K ij t͑t ͒͑no sum ͒͑22͒where K ij 0=elastic contribution of stiffness matrix and K t=time dependent portion.Using Eqs.͑20͒and ͑22͒,one can summarize the problem asK ij 0͑x ͒K ˜ij t ͑s ͒U ˜j ͑s ͒=F ˜i ͑x ,s ͒+F ˜i th ͑x ,s ͒͑no sum ͒͑23͒FE ImplementationThe FE formulation described in the previous section was imple-mented and applied to two-dimensional plane and axisymmetricproblems.This section provides the details of the implementation of formulation along with brief description method chosen for numerical inversion from Laplace domain to time domain.The implementation was coded in the commercially available software Matlab.The implementation of the analysis code is di-vided into ﬁve major steps as shown in Fig.2.The ﬁrst step is very similar to the FE method for a time dependent nonhomogeneous problem,whereby local contribu-tions from various elements are assembled to obtain the force vector and stiffness matrix for the system.Notice that due to the time dependent nature of the problem the quantities are evaluated throughout the time duration of analysis.The next step is to trans-form the quantities to the Laplace domain from the time domain.For the generalized Maxwell model,the Laplace transform of the time-dependent portion of the stiffness matrix,K t ,can be directly ͑and exactly ͒determined using the analytical transform given byK ij 0͑x ͒K ˜ij t ͑s ͒U ˜j ͑s ͒=F ˜i ͑x ,s ͒+F ˜i th ͑x ,s ͓͒no sum for K ij 0͑x ͒K ˜ij t ͑s ͔͒͑24͒Laplace transform of quantities other than the stiffness matrix canbe evaluated using the trapezoidal rule,assuming that the quanti-ties are piecewise linear functions of time.Thus,for a given time dependent function F ͑t ͒,the Laplace transform F ˜͑s ͒is estimated asF ˜͑s ͒=͚i =1N −11s 2⌬t͕s ⌬t ͑F ͑t i ͒Exp ͓−st i ͔−F ͑t i +1͒Exp ͓−st i +1͔͒+⌬F ͑Exp ͓−st i ͔−Exp ͓−st i +1͔͖͒͑25͒where ⌬t =time increment;N =total number of increments;and⌬F =change in function F for the given increment.Once the quantities are calculated on the transformed domain the system of linear equations are solved to determine the solu-tion,which in this case produces the nodal displacements in thetransformed domain,U˜͑s ͒.The inverse transform provides the solution to the problem in the time domain.It should be noted that()1C x ()2C x ()n C x τττ12nFig.1.Generalized Maxwell modelDefine problem in time-domain (evaluate load vector F(t)and stiffnessmatrix components K 0(t)and K t (x ))Perform Laplace transform to evaluate F(s)and K t (s)~~Solve linear system of equations to evaluate nodal displacement,U(s)Perform inverse Laplace transforms to get the solution,U(t)~Post-process to evaluate field quantities of interestFig.2.Outline of ﬁnite-element analysis procedure42/JOURNAL OF MATERIALS IN CIVIL ENGINEERING ©ASCE /JANUARY 2011the formulation as well as its implementation is relatively straight forward using the correspondence principle based transformed ap-proach when compared to numerically solving the convolution integral.The inverse Laplace transform is of greater importance in the current problem as the problem is ill posed due to absence of a functional description in the imaginary prehensive comparisons of various numerical inversion techniques have been previously presented ͑Beskos and Narayanan 1983͒.In the current study,the collocation method ͑Schapery 1962;Schapery 1965͒was used on basis of the recommendations from previous work ͑Beskos and Narayanan 1983;Yi 1992͒.For the current implementation the numerical inverse trans-form is compared with exact inversion using generalized Maxwell model ͓c.f.Eq.͑21͔͒as the test function.The results,shown in Fig.3,compare the exact analytical inversion with the numerical inversion results.The numerical inversion was carried out using 20and 100collocation points.With 20collocation points,the average relative error in the numerical estimate is 2.7%,whereas with 100collocation points,the numerical estimate approaches the exact inversion.Veriﬁcation ExamplesIn order to verify the present formulation and its implementation,a series of veriﬁcations were performed.The veriﬁcation was di-vided into two categories:͑1͒veriﬁcation of the implementation of GIF elements to capture material nonhomogeneity,and ͑2͒veriﬁcation of the viscoelastic portion of the formulation to cap-ture time and history dependent material response.Veriﬁcation of Graded ElementsA series of analyzes were performed to verify the implementation of the graded elements.The veriﬁcations were performed for ﬁxed grip,tension and bending ͑moment ͒loading conditions.The material properties were assumed to be elastic with exponential spatial variation.The numerical results were compared with exact analytical solutions available in the literature ͑Kim and Paulino 2002͒.The comparison results for ﬁxed grip loading,tensile load-ing,and bending were performed.The results for all three casesshow a very close match with the analytical solution verifying the implementation of the GIF graded parison for the bending case is presented in Fig.4.Veriﬁcation of Viscoelastic AnalysisVeriﬁcation results for the implementation of the correspondence principle based viscoelastic functionally graded analysis were performed and are provided.The ﬁrst veriﬁcation example repre-sents a functionally graded viscoelastic bar undergoing creep de-formation under a constant load.The analysis was conducted for the Maxwell model.Fig.5compares analytical and numerical results for this veriﬁcation problem.The analytical solution ͑Mukherjee and Paulino 2003͒was used for this analysis.It can be observed that the numerical results are in very good agreement with the analytical solution.The second veriﬁcation example was simulated for ﬁxed grip loading of an exponentially graded viscoelastic bar.The numeri-cal results were compared with the available analytical solution24F u n c t i o n ,f (t )T e s t Time (sec)Fig.3.Numerical Laplace inversion using collocation method-y -y D i r e c t i o n (M P a )E (x)--S t r e s s i n -x (mm)parison of exact ͑line ͒and numerical solution ͑circular markers ͒for bending of FGM bar ͑insert illustrates the boundary value problem along with material gradation ͒m )y e n t i n y D i r e c t i o n (m E(x)D i s p a l c e m x (mm)parison of exact and numerical solution for the creep ofexponentially graded viscoelastic barJOURNAL OF MATERIALS IN CIVIL ENGINEERING ©ASCE /JANUARY 2011/43͑Mukherjee and Paulino 2003͒for a viscoelastic FGM.Fig.6compares analytical and numerical results for this veriﬁcation problem.Notice that the results are presented as function of time,and in this boundary value problem the stresses in y-direction are constant over the width of bar.Excellent agreement between nu-merical results and analytical solution further veriﬁes the veracity of the viscoelastic graded FE formulation derived herein and its successful implementation.Application ExamplesIn this section,two sets of simulation examples using the gradedviscoelastic analysis scheme discussed in this paper are presented.The ﬁrst example is for a simply supported functionally graded viscoelastic beam in a three-point bending conﬁguration.In order to demonstrate the beneﬁts of the graded analysis approach,com-parisons are made with analysis performed using commercially available software ͑ABAQUS ͒.In the case,of ABAQUS simula-tions,the material gradation is approximated using a layered ap-proach and different reﬁnement levels.The second example is that of an aged conventional asphalt concrete pavement loaded with a truck tire.Simply Supported Graded Viscoelastic BeamFig.7shows the geometry and boundary conditions for the graded viscoelastic simply supported beam.A creep load,P ͑t ͒,is imposed at midspanP ͑t ͒=P 0t͑26͒The viscoelastic relaxation moduli on the top ͑y=y 0͒and bottom ͑y=0͒of the beam are shown in Fig.8.The variation of moduli is assumed to vary linearly from top to bottom as follows:E ͑y ,t ͒=ͩyy 0ͪE Top ͑t ͒+ͩy 0−y y 0ͪE Bottom ͑t ͒͑27͒The problem was solved using three approaches namely,͑1͒graded viscoelastic analysis procedure ͑present paper ͒;͑2͒com-mercial software ABAQUS with different levels of mesh reﬁne-ments and averaged material properties assigned in the layered manner;and ͑3͒assuming averaged material properties for the whole beam.In the case of the layered approach using commer-cial software ABAQUS,three levels of discretization were used.A sample of the mesh discritization used for each of the simula-tion cases is shown in Fig.9.Table 1presents mesh attributes for each of the simulation cases.The parameter selected for comparing the various analysis op-tions is the mid span deﬂection for the beam problem discussed earlier ͑c.f.Fig.7͒.The results from all four simulation options are presented in Fig.10.Due to the viscoelastic nature of the problem,the beam continues to undergo creep deformation with increasing loading time.The results further illustrate the beneﬁt of using the graded analysis approach as a ﬁner level of meshTable 1.Mesh Attributes for Different Analysis Options Simulation case Number of elements Number of nodes Total degrees of freedom FGM/average/6-layer 7201,5733,1469-layer 1,6203,4396,87812-layer2,8806,02512,050y E 0(x )t i me (sec)parison of exact and numerical solution for the exponen-tially graded viscoelastic bar in ﬁxed grip loadingy()()0P t P h t =xx 0=10y 0=1x 0/2Fig.7.Graded viscoelastic beam problemconﬁgurationE 0(M P a )l x a t i o n M o d u l u s ,E (t )/N o r m a l i z e d R e 10101010time (sec)Fig.8.Relaxation moduli on top and bottom of the graded beamFG M A verage 6-Layer 9-Layer 12-LayerFig.9.Mesh discretization for various simulation cases ͑1/5th beam span shown for each case ͒。

The Effect of Body Position on GER in Premature Infants-Corvaglia-2007

The Effect of Body Positioning on Gastroesophageal Reﬂux in Premature Infants:Evaluation by Combined Impedance and pH MonitoringL UIGI C ORVAGLIA,MD,R AFFAELLA R OTATORI,MD,M ARIANNA F ERLINI,MD,A RIANNA A CETI,MD,G INA A NCORA,MD,AND G IACOMO F ALDELLA,MDObjective To evaluate the pattern of acid and nonacid gastroesophageal reﬂux(GER)in different body positions in preterm infants with reﬂux symptoms by a combined multichannel intraluminal impedance(MII)–pH monitoring,which identiﬁes both acid and nonacid GER.Study design Premature infants with frequent regurgitation and postprandial desaturation(n؍22)underwent a24-hour recording of MII-pH.In a within-subjects design,reﬂux indexes were analyzed with the infants in4different positions:supine (S),prone(P),on the right side(RS),and on the left side(LS).Results All infants were analyzed for20hours.The mean number of recorded GER episodes was109.7.The mean esophageal exposure to acid and nonacid GER was lower in positions P(4.4%and0.3%,respectively)and LS(7.5%and0.7%, respectively)than in positions RS(21.4%and1.2%,respectively)and S(17.6%and1.3%,respectively).The number of postprandial nonacid GER episodes decreased but the number of acid GER episodes increased over time.The LS position showed the lowest esophageal acid exposure(0.8%)in the early postprandial period,and the P position showed the lowest esophageal acid exposure(5.1%)in the late postprandial period.Conclusion Placing premature infants in the prone or left lateral position in the postprandial period is a simple intervention to limit GER.(J Pediatr2007;151:591-6)G astroesophageal reﬂux(GER)is common in premature infants.Because it may be linked to serious clinical conse-quences,it is cause for concern in neonatologists and parents and necessitates prolongation of hospitalization.1,2As in term infants,3a conservative approach based on postural treatment has been suggested in preterm infants with GER.1 However,few studies have been performed to investigate the best body position for this approach to GER treatment in premature infants,and results are not ing pH monitoring,Ewer et al4found that prone and left lateral positioning was more effective in preventing GER.Omari et al,5using combined manometry and multichannel intraluminal impedance (MII)recording in preterm infants asymptomatic for GER,found that left lateral positioning was more advantageous than right lateral positioning.These authors analyzed the mechanisms triggering GER and observed an increased number of transient lower esophageal sphincter relaxations(TLESRs)in the right lateral position,despite a gastricemptying rate twice that in the left lateral position.Despite these importantﬁndings,thisstudy was unable to differentiate acid and nonacid GER.5The effect of positioning is predictable based on previous work,but it is importantto describe this effect using the current state-of-the-art methods for GER measurement.Consequently,the aim of our study was to evaluate the affect of body position on GERin symptomatic premature infants using combining intraluminal impedance and pHmonitoring.MII is based on the intraluminal electrical impedance changes occurring duringthe passage of a bolus through the esophagus.It is measured by electrodes incorpo-rated along a catheter.Impedance is decreased if the bolus is liquid and is increasedif it is air.The direction of the bolus is determined by evaluating changes inintraluminal impedance at various levels over time.6MII can detect gas,mixed,andBEI Bolus exposure indexGER Gastroesophageal reﬂuxLES Lower esophageal sphincterLS Left sideMACT Mean acidic clearing timeMII Multichannel intraluminal impedance P ProneRIpH Reﬂux indexRS Right sideS SupineTLESR Transient lower esophageal sphincterrelaxationSee editorial,p560andrelated article,p585From the Institute of Preventive Pediatricsand Neonatology,St.Orsola Malpighi Gen-eral Hospital,University of Bologna,Bolo-gna,Italy(L.C.,R.R.,M.F.,A.A.,G.A.,G.F.).Submitted for publication Feb1,2007;lastrevision received Apr27,2007;acceptedJun6,2007.Reprint requests:Luigi Corvaglia,MD,Istitutodi Pediatria Preventiva e Neonatologia,ViaMassarenti11,40138Bologna,Italy.E-mail:luicorva@almadns.unibo.it.0022-3476/$-see front matterCopyright©2007Mosby Inc.All rightsreserved.10.1016/j.jpeds.2007.06.014591liquid GER episodes but cannot differentiate acid and non-acid episodes;for this reason,it is essential to combine MII and pH monitoring to evaluate the role of acid and nonacid GER episodes.METHODSA total of22(16male)symptomatic premature infants with a median gestational age at birth of31weeks(range,24 to32weeks)and a median birth weight of1220g(range,630 to2250g)were enrolled in the study at a median age of29 days(range,12to83days)and a median weight of1747g (range,1150to3215g).The infants exhibited frequent re-gurgitation and postprandial desaturation;in addition,7in-fants had postprandial apnea,4had failure to thrive,1had bradycardia,and1had both postprandial apnea and brady-cardia.All were otherwise healthy at the time of examination. None had malformation or major gastrointestinal problems or was taking drugs inﬂuencing gastrointestinal motility or gas-tric acidity.Seven infants were fed extracted human milk fortiﬁed with3%FM85(Nestlé,Vevey,Switzerland),3were fed a standard preterm formula,and the remaining12re-ceived both.All22infants tolerated at least100ml/kg per day of milk.The effect of postural intervention on GER was eval-uated in a within-subjects design,taking for each subject measurement of GER in different postural conditions.In a within-subjects design,the same subjects are tested in each condition;therefore,differences among subjects can be sep-arated from error,increasing the power of signiﬁcance tests.A possible drawback of this method is the“carry-over”effect—a persistent effect in a subsequent treatment period from treat-ment in the previous period.In our study,this could be represented by the effect on GER of each position on the subsequent position.To limit this effect,we randomly as-signed to each enrolled infant a different sequence of the possible postural combinations.Postural InterventionIn the24-hour examination,4positions—supine(S), prone(P),right side(RS),and left side(LS)—were studied. Each position was maintained for6hours,except for2 periods of30minutes each for feeding.The order of different positions was assigned randomly and was not known by the data analysts.Each infant received8meals(1every3hours) through a feeding bottle or an orogastric tube,inserted and removed at each meal.This approach allowed us to include2 meals and2150-minute postprandial periods in each body position.GER MonitoringEach patient underwent a24-hour,continuous,simul-taneous measurement of intraesophageal pH and multichan-nel electrical impedance.The system was calibrated before each measurement using pH buffer solutions of pH4.0and pH7.0.A single-use combined MII–pH probe(Comfortec MII-pH,2.1mm in diameter;Sandhill Scientiﬁc,Highlands Ranch,CO)was used.Theﬂexible catheter contained seven impedance electrodes representing6bipolar impedance chan-nels and1antimony electrode for pH detection.The distance between each impedance electrode was1.5cm,except for the distal couple spaced at2cm.The pH sensor was located1cm above the distal impedance ring,in the middle of the most distal impedance-measurement segment.The catheter was inserted through a nostril without sedation and placed under ﬂuoroscopic guidance.The tip wasﬁxed1to1.5cm above the gastroesophageal junction.Before removal,the position of the catheter was compared with the initial position by checking the depth mark on the catheter,to exclude possible displace-ment.Data were acquired on a portable Sleuth system(San-dhill Scientiﬁc),stored at the end of each test in a personal computer,and analyzed by BioVIEW Analysis software,ver-sion5.0.9(Sandhill Scientiﬁc)and by direct visual evaluation of each event.During each GER episode,we recorded the minimum pH value;the height(in cm),calculated by the distance from the lower esophageal sphincter(LES)of the most proximal electrode that detected the reﬂux;and the duration(in sec-onds),deﬁned as the time between the onset of GER and the recovery of50%of the initial impedance value,measured at the level of the distal impedance bipolar channel(ie,1.5cm). To be detected as MII-GER,the bolus,moving in a retro-grade direction,had to contact at least3impedance elec-trodes,reaching a height of at least4to4.5cm above the gastroesophageal junction.An MII-GER episode was de-ﬁned as acid(aMII-GER)if the pH wasϽ4and as nonacid (NaMII-GER)if the pH wasՆ4.7The total percentage of time with a MII-GER in the esophagus was indicated as bolus exposure index(BEI)and further separated into acid (aMII-GER-BEI)and nonacid(NaMII-GER-BEI)reﬂux indexes.The number of all acid GERs,including those detected only by pH electrode and those detected by MII as well,was classiﬁed as pH-acid-GER.The total percent time of esoph-ageal exposure to a pHϽ4was designated as the reﬂux index (RIpH).This latter measurement substantially represents a traditional pH monitoring and includes periods of acid esophageal exposure associated with retrograde movement detected by MII and periods with acid esophageal exposure not associated with retrograde movement detected by MII. The mean time(in seconds)required for pH to return to4 after a GER episode was designated the mean acidic clear-ing time(MACT).Because the features of GER change during postpran-dial hours,8we further analyzed and compared GER indexes measured during theﬁrst75postprandial minutes(ﬁrst pe-riod)with those measured during the second75postprandial minutes(second period).The study design was approved by the hospital’s Insti-tutional Ethics Committee.Written informed consent was obtained from a parent of each infant enrolled in the study.592Corvaglia et al The Journal of Pediatrics•December2007Statistical AnalysisAll statistical analyses were performed with SPSS13.0 for Windows(SPSS Inc,Chicago IL).Normal distribution wasﬁrst evaluated by the Kolmogorov-Smirnov test.Reﬂux variables in each position were analyzed using generalized likelihood model repeated-measures design(1within-subjects factor)and Bonferroni post hoc pairwise comparison;differ-ences between theﬁrst and second postprandial periods were tested by paired-sample t tests.A P valueϽ.05was consid-ered statistically signiﬁcant.RESULTSThe test was well tolerated by all of the patients,and their clinical status remained stable.No probe position changes were detected during any examination.We analyzed a total of176postprandial periods(44periods for each position),with a mean duration of149minutes(range,145to 157minutes).RIpH measurements in the22patients are given in Table I.During the20-hour monitoring(24hours minus4 feeding hours),the mean total number of recorded GER episodes was109.7(5.5per hour).The mean numbers of aMII-GER,NaMII-GER,and pH-acid-GER episodes were 11.7,35.9,and73.7,respectively,with corresponding mean percent times of esophageal exposure to reﬂux of0.3%,0.9%, and12.7%.Effect of Position on the Physical Compositionof ReﬂuxateGER episodes wereﬁrst analyzed regarding physical composition of the reﬂuxate.In each position,most of the GER reﬂuxate was liquid,although some was gaseous or mixed.Liquid reﬂuxate was signiﬁcantly less frequent in the LS and P positions compared with the RS and S positions (PϽ.01)(Table I).There were no signiﬁcant differences among positions regarding gaseous and mixed episodes. Effect of Position on Impedance-Detected andpH-Detected ReﬂuxWhen values were analyzed by different positions,we observed a reduction of each type of MII-pH–detected GER in the LS and P positions compared with the RS and S positions(Figures1and2).In particular,acid exposure time (RIpH)and MACT were signiﬁcantly lower in both the P and LS positions compared with the S and RS positions.We found no difference between the P and LS positions.The P position exhibited signiﬁcantly fewer Na-MII-GER episodes than the other3positions.Table I.Reﬂux parameters measured in the22patientsTotal Left side Right side Supine Prone PLiquid GER(n)40.5(20.5)0-877.9(4.8)0-2013.6(8.8)0-3015.9(9.7)0-393.1(2.6)0-10LS vs RS:.012LS vs S:.002P vs RS,S,LS:.001Gaseous GER(n) 4.8(5.2)0-191.7(2.1)0-81.1(1.4)0-50.9(1.2)0-41.1(2)0-8NSMixed GER(n)7.4(5.9)0-222.3(2.6)0-112.5(2.9)0-131.7(1.9)0-70.8(1.4)0-6NSaMII-GER(n)11.7(9.1)1-351.9(2.1)0-84.2(4.4)0-184.3(3.5)0-121.1(1.2)0-3P vs S:.001P vs RS:.019LS vs S:.029NaMII-GER(n)35.9(22)2-918.3(5.8)0-2111.9(8.9)0-3612.9(9.1)1-352.8(2.6)0-8P vs RS,S,LS:.001pH-acid-GER(n)73.7(44.3)3-14917.9(15.7)0-5627.1(18.1)3-6621.9(15.3)0-566.8(5.3)0-17P vs S,RS:.001P vs LS:.006aMII-GER-BEI(%)0.3(0.2)0-0.70.2(0.3)0-10.5(0.5)0-1.70.5(0.5)0-1.70.1(0.1)0-0.4P vs RS:.001P vs S:.006RS vs LS:.015NaMII-GER-BEI(%)0.9(0.5)0-1.80.7(0.6)0-2.11.2(0.9)0-2.61.3(1)0.11-3.30.3(0.3)0-1P vs S,RS:.0001LS vs S:.011RipH(%)12.7(10.5)1.6-37.97.5(8.2)0-32.221.4(19.4)0.4-68.417.6(16.1)0-48.64.4(5.8)0-19.8P vs RS:.001P vs S:.002LS vs RS:.004LS vs S:.014MACT(sec)119.8(116.1)26.4-582.693.2(143.9)0-701.8176.4(245.6)26.4-1216.9162.7(103)17.1-282.994.9(91.1)0-257.1P vs S:.016LS vs RS:.021Mean MII-GER height(cm)3.5(1.2)1.8-7.23.9(1.7)1.7-93.4(1.2)1.5-73.8(1.3)1.7-7.33(1.4)0-7NSNS,not signiﬁcant.Values are expressed as mean(standard deviation)and range.The Effect of Body Positioning on Gastroesophageal Reﬂux in Premature Infants:Evaluation by Combined Impedanceand pH Monitoring593Improvement in all GER indexes in the P and LS positions was seen in all patients except 1,who showed better GER indexes in the S and RS positions than in the P and LS positions.In this patient,an upper radiograph study with a barium swallow performed after MII-pH monitoring dem-onstrated a gastric malrotation.We decided not to exclude this patient from the analysis,because the inclusion criteria were fulﬁlled,and the diagnosis of malrotation was made after the MII-pH monitoring had been performed.Moreover,we veriﬁed that the exclusion of this patient would not have affected the global results;in fact,in an analysis performed excluding this patient,all statistical signiﬁcances did not vary (data not showed).Inﬂuence of Position on the Height of GER EpisodesNo difference among positions was found in mean height reached by GER episodes.Changes in the Composition of Postprandial Reﬂuxate Over TimeComparison of the 2postprandial periods (Table II )revealed that acid GER indexes (RIpH and aMII-GER-BEI)were signiﬁcantly higher in the second postprandial period than in the ﬁrst postprandial period in all of the positions studied except P.In the ﬁrst postprandial period,the P and LS positions were associated with a signiﬁcantly lower RIpH compared with the S and RS positions (P Ͻ.01).RIpH was the lowest in the LS position (with 12of the 22patients having a RipH of 0%),signiﬁcantly lower than in the P position (LS ϭ0.8%vs P ϭ3.6%;P Ͻ.05)(Figure 3;available at ).During the second postprandial period,the P position was associated with strongly reduced esophageal acid exposure compared with the other 3positions (P Ͻ.01).RIpH was lower in the LS than in the S and RS position (P Ͻ.01);however,RIpH was signiﬁcantly higher in the LS position than in the P position (14.3%vs 5%;P ϭ.016).In the ﬁrst postprandial period,Na-MII-GER-BEI was signiﬁcantly lower in the P position compared with the RS and S positions (P Ͻ.05);in the second postprandial period,Na-MII-GER-BEI was signiﬁcantly lower in the P position compared withall of the other positions (P Ͻ.01)(Figure 4;available at ).DISCUSSIONIn this study,we found fewer GER episodes when infants were placed in the LS and P positions compared with the RS and S positions.Body position had no inﬂuence on the proximal extent of MII-detected GER episodes.In each body position,we noticed a decrease in the number of postprandial nonacid GER episodes and an increase in the number of postprandial acid GER episodes over time.GER is common in preterm infants;the almost ﬁxed lying position promotes the entry of liquid gastric contents into the esophagus when TLESR occurs.Additional risk factors associated with preterm birth include high total ﬂuid enteral intake,frequent handling by nurses,and the use of permanent feeding tubes.9A study in asymptomatic preterm neonates found a median of 71reﬂux episodes in 24hours.10Although GER is asymptomatic in most preterm infants,in some it may cause such symptoms as desaturation,regurgitation,and bradycar-dia or can lead to such complications as apnea,recurrent desaturation and/or aspiration,difﬁculties in oral feeding,vomiting,and failure to thrive.1Although acid reﬂux episodes are considered more likely associated with symptoms in pre-term infants,11recent studies indicate that nonacid reﬂux can produce these symptoms as well.12For preterm infants with symptomatic GER,a stepwise approach,based mainly on conservative interventions,is the best therapeutic choice.Drugs should be the last option,considering that cisapride was withdrawn from the market because of its possible cardiac side effects,13and treatment with gastric acid inhibitors is not without risk.14,15In a previous study,we found no reduction of GER from thickening human milk with precooked starch.16More-over,a possible relationship between milk thickening and the development of necrotizing enterocolitis has been described in 2preterm infants.17Few studies have evaluated the inﬂuence of body posi-tion on acid GER in preterm newborns,and,to the best of our knowledge,none have investigated the inﬂuence of body position on nonacid GER.Omari et al 5evaluated the inci-dence of GER in 10newborns with mild prematurity and without GER symptoms using a combined MII and manom-etry catheter and found an advantage of LS over RS position-ing in terms of a reduced number of GER episodes.Although that study provided important data concerning GER patho-logical mechanisms,the presence of a trans-LES catheter could have increased the number of GER episodes,and the absence of a pH sensor did not allow the authors to differ-entiate acid and nonacid episodes.Another study conﬁrmed these ﬁndings in 18premature babies with GER symptoms using pH monitoring and comparing the P position with the RS and LS positions.4But that study evaluated only acid episodes with no information about the S position,the most frequently used position in both term and in pretermnew-Figure 1.RIpH in different body positions (—,median;---,95th percentile).594Corvaglia et alThe Journal of Pediatrics •December 2007borns.Recognizing that nonacid reﬂux episodes are common in premature infants,we believe that combined MII-pH monitoring is the most appropriate method for evaluating GER in preterm newborns.In our study,RIpH was mostly measured only by a pH electrode (placed 1.5to 2cm above the diaphragm),not by MII (with the most distal 2electrodes placed at about 4.5cm above diaphragm).Thus,GER episodes were detected in 2different esophageal sites 3cm apart;this distance is partic-ularly relevant considering the total esophageal length of about 6to 10cm.For this reason,we can state that in symptomatic preterm infants,most GER occurs in the distal half of the esophagus.Even in adults,a 6-fold increase in acid exposure (mean RipH,11.7%vs 1.8%)was found between the more distal and proximal pH measurements.18Our data are not comparable with those from previous studies,due to methodological differences.Wenzl,6Skopnik et al,19and others reported that most GER episodes reached the proximal esophagus because they considered as GER episodes only those detectable by both MII and pH probes.In comparison,we also considered numerous short-segment ep-isodes detected only by the pH probe.Omari et al 11charac-terized most GER episodes as nonacid,because they ﬁrst detected all GER episodes by manometry just above the LES and then classiﬁed them as acid or nonacid by a pH electrode.In contrast,we were able to detect GER episodes just above the LES only by the pH probe.We found that the P and LS positions signiﬁcantly decreased the number of acid and nonacid GER episodes compared with the S and RS positions.The effect of theLSFigure 2.aMII-BEI and NaMII-BEI in different body positions (—,median;---,95th percentile).(aMII-BEI:P vs RS P ϭ.001,P vs S ϭP ϭ.006,RS vs LS P ϭ.015;NaMII-BEI:P vs RS P ϭ.0001,P vs S ϭP ϭ.0001,RS vs LS P ϭ.011.)Table II.Variation of acid and nonacid GER during postprandial periodsRIpHP aMII-GER-BEI P NaMII-GER-BEI P Left sideFirst period 0.8(1.5)0-5.5.0010(0.1)0-0.3.031.2(1)0-3.7.0001Second period 14.3(16)0-64.40.2(0.5)0-20.2(0.2)0-0.6Right side First period 9.9(21)0-92.1.0010.3(0.5)0-2.2.01 2.2(1.7)0-5.2.0001Second period 32.9(26.1)0.7-84.30.8(0.9)0-2.50.2(0.3)0-0.8SupineFirst period 5.4(13.4)0-54.9.00010.1(0.2)0-0.6.0001 2.2(1.7)0.2-5.5.0001Second period 29.7(25.6)0-72.60.9(0.9)0-3.10.4(0.8)0-3.1ProneFirst period 3.6(8.7)0-37.3NS 0(0.1)0-0.4.040.7(0.6)0-2.0.0001Second period 5.1(7.3)0-33.70.1(0.2)0-0.90(0.1)0-0.5TotalFirst period 4.9(9.3)0-34.3.00010.1(0.1)0-0.5.001 1.6(0.9)0.1-3.5.0001Second period20.5(14.3)0.2-47.80.5(0.4)0-1.40.21(0.3)0-1.0Values are expressed as mean (standard deviation)and range.The Effect of Body Positioning on Gastroesophageal Reﬂux in Premature Infants:Evaluation by Combined Impedance and pH Monitoring595position in reducing GER is due mainly to a functional factor—reduced TLESR episodes—by laying the gastric con-tents on the gastric body and greater curvature,which to-gether act as a reservoir.5The effect of the P position is related mainly to an anatomic factor.In this position,the LES is above the gastric body,far from the gastric contents;4 thus,when a TLESR occurs,the gastric contents are farther from the LES and are less likely to go back into the esoph-agus.Our separate analysis of the incidence of acid and non-acid GER episodes and the relationship with different body positions in theﬁrst and second postprandial periods revealed that in theﬁrst period,the degree of acid esophageal exposure was4-fold higher in the P position compared with the LS position(percent time,3.6%vs0.8%;PϽ.05).In dyspeptic adults,after meals in upright position,a pocket of unbuffered acid juice forms near the gastroesophageal junction;it seems to escape the buffering effects of meals,remaining highly acid compared with the body of the stomach.20The presence of a similar pocket in preterm infants lying in the P position could explain the higher esophageal acid exposure in the P position than in the LS position during theﬁrst postprandial period. In contrast,in the second postprandial period,esophageal acid exposure was higher in the LS position than in the P position(Pϭ.016).Theseﬁndings suggest that acid exposure can be optimally reduced by keeping the newborn on the left side during the early postprandial period and in the prone position thereafter.In conclusion,our study suggests that placing prema-ture infants in a prone or left lateral position during the postprandial period is a simple intervention to limit GER. Ourﬁndings do not provide any information on clinical improvement,because the study was not designed to monitor the effect of postural intervention on GER symptoms.Fur-ther studies are needed to evaluate the effective correlation between postural intervention and improvement of GER symptoms.REFERENCES1.Poets CF.Gastroesophageal reﬂux:a critical review of its role in preterm infants. Pediatrics2004;113:128-32.2.Frakaloss G,Burke G,Sanders MR.Impact of gastroesophageal reﬂux on growth and hospital stay in premature infants.J Pediatr Gastroenterol Nutr 1998;26:146-50.3.Tobin JM,McCloud P,Cameron DJS.Posture and gastro-oesophageal reﬂux:a case for left lateral positioning.Arch Dis Child1997;76:254-8.4.Ewer AK,James ME,Tobin JM.Prone and left lateral positioning reduce gastro-oesophageal reﬂux in preterm infants.Arch Dis Child Fetal Neonatal Ed 1999;81:F201-5.5.Omari TI,Rommel N,Staunton E,Lontis R,Goodchild L,Haslam RR,et al. Paradoxical impact of body positioning on gastroesophageal reﬂux and gastric emptying in the premature neonate.J Pediatr2004;145:194-200.6.Wenzl TG.Investigating esophageal reﬂux with the intraluminal impedance technique.J Pediatr Gastroenterol Nutr2002;34:261-8.7.Sifrim D,Castell D,Dent J,Kahrilas PJ.Gastro-esophageal reﬂux monitoring: review and consensus report on detection and deﬁnitions of acid,nonacid,and gas reﬂux. Gut2004;53:1024-31.8.Wildi SM,Tutuian R,Castell DO.The inﬂuence of rapid food intake on postprandial reﬂux:studies in healthy volunteers.Am J Gastroenterol2004;99:1645-51.9.Peter CS,Wiechers C,Bohnhorst B,Silny J,Poets C.Inﬂuence of nasogastric tubes on gastroesophageal reﬂux in preterm infants:a multiple intraluminal impedance study.J Pediatr2002;14:277-9.10.Lòpez-Alonso M,Moya MJ,Cabo JA,Ribas J,Macias MdC,Silny J,et al. Twenty-four-hour esophageal impedance-pH monitoring in healthy preterm neonates: rate and characteristics of acidic,weakly acidic,and weakly alkaline gastroesophageal reﬂux.Pediatrics2006;118:e299-308.11.Omari TI,Barnett CP,Benninga MA,Lontis R,Goodchild L,Haslam RR,et al. Mechanism of gastro-oesophageal reﬂux in preterm and term infants with reﬂux disease. Gut2002;51:475-9.12.Wenzl TG,Silny J,Schenke S,Peschgens T,Heimann G,Skopnik H.Gastro-esophageal reﬂux and respiratory phenomena in infants:status of the intraluminal impedance technique.J Pediatr Gastroenterol Nutr1999;28:423-8.13.Corvaglia L,Faldella G,Rotatori R,Lanari M,Capretti MG,Salvioli GP. Intrauterine growth retardation is a risk factor for cisapride-induced QT prolongation in preterm infants.Cardiovasc Drug Ther2004;18:371-5.14.Guillet R,Stoll BJ,Cotten CM,Gantz M,McDonald S,Poole WK,Phelps DL, National Institute of Child Health and Human Development Research Network. Association of H2-blocker therapy and higher incidence of necrotizing enterocolitis in very low birth weight infants.Pediatrics2006;117:e137-42.15.Canani RB,Cirillo P,Roggero P,Romano C,Malamisura B,Terrin G,et al, Working Group on Intestinal Infections of the Italian Society of Pediatric Gastroen-terology,Hepatology and Nutrition.Therapy with gastric acidity inhibitors increases the risk of acute gastroenteritis and community-acquired pneumonia in children.Pediatrics 2006;117:e817-20.16.Corvaglia L,Ferlini M,Rotatori R,Paoletti V,Alessandroni R,Cocchi G,et al. Starch thickening of human milk is ineffective in reducing the gastroesophageal reﬂux in preterm infants:a crossover study using intraluminal impedance.J Pediatr2006; 148:265-8.17.Clarke P,Robinson MJ.Thickening milk feeds may cause necrotizing enteroco-litis.Arch Dis Child Fetal Neonatal Ed2004;89:F280.18.Fletcher J,Wirz A,Henry E,McColl KEL.Studies of acid exposure immediately above the gastro-oesophageal squamocolumnar junction:evidence of short segment reﬂux.Gut2004;53:168-73.19.Skopnik H,Silny J,Heiber O,Schulz J,Rau G,Heimann G.Gastroesophageal reﬂux in infants:evaluation of a new intraluminal impedance technique.J Pediatr Gastroenterol Nutr1996;23:591-8.20.Fletcher J,Wirz A,Young J,Vallance R,McColl KEL.Unbuffered highly acidic gastric juice exists at the esophageal junction after a meal.Gastroenterology2001; 121:775-83.596Corvaglia et al The Journal of Pediatrics•December2007。

acca F4 背诵讲义

Chapter 1 Structure of the legal system1. ESSENTIAL ELEMENTS OF THE LEGAL SYSTEMLaw•Law is a formal control mechanism.•It provides a structure for dealing with and resolving disputes.•It also provides some deterrent to those wishing to disrupt social order.Common law•Common law developed in England during the period following the Norman Conquest.•It was made by judges who travelled around the country to keep the King’s peace and made law by merging local customary laws into one ‘law of the land’.•Today, the concept of PRECEDENT continues to be the key feature of commom law, and distinguishes it from other legal systems.•Remedies under common law are monetary, and are known as damages.Equity•Common law does not provide justice to the wronged person if monetary compensation is not suitable.•Equity developed two or three hundred years after common law as a system to resolve disputes where damages are not a suitable remedy and therefore introduced fairnessinto the legal system.•For example, where a person needs to stop another person’s behaviour or to force them to act as they agreed to, equity provides remedies to achieve this.Civil law•Civil law exists to resolve disputes over the rights and obligations of persons dealing with each other and seeks to compensate wronged parties.•It is a form of private law (between individuals) and covers areas such as tort, contract and employment law.•In civil proceedings, the case must be proved on the balance of probability, the object is to convince the court that it is probable that a person’s assertions are ture.•There is no concept of punishment in the civil law and compensation is paid to the wronged person.•If they wish, both parties may choose to settle the dispute out of court.Criminal law• A crime is conduct that is prohibited by the law.•Criminal law is a form of public law (betweent the State and individuals).•In criminal proceedings, the State is the procecutor because it is the community as a whole which suffers as a result of the law being broken.•The burden of proof to convict the accused(认定被告有罪) rests with the procecution, which must prove its case beyond reasonble doubt.•In the UK, the police take the initial decision to prosecute, this is then reviewed by the Crown Prosecution Service. However, some prosecutions are started by the Director of Public Prosecutions, who is the head of the Crown Prosecution Service.•Persons guilty of crime may be punished by fines payable to the State, imprisonment, ora community-based punishment.The distinction between civil law and criminal lawThis is not an act or event which creates the distinction between civil and criminal law, but the legal consequences. A single event might give rise to both civil and criminal proceedings.2. JURISDICTION OF CIVIL COURTS•The nature of the case and the size of the claim will determine which court hears a civil case.•The County courts hear small cases ( claims under £5,000) or those which are deemed to be ‘FAST TRACK’ cases. The case is heard by a Circuit Judg e assisted by DistrictJudges.•Complicated cases or those which are deemed to be ‘MULTI TRACK’ cases are heard at the High Court.•The Queen’s Bench Division hears cases concerning contract and tort issues.•The Family Division hears cases concerning children and matrimonial issues.•The Chancery Division hears cases concerning trusts, bankruptcy and corporate issures.•Appeals are to the Civil Division of the Court of Appeal and are heard by three judges who will decide the outcome by a majority.• A further appeal to the Supreme Court for the United Kingdom may be permitted if it involves an issue of public interests.3. JURISDICTION OF CRIMINAL COURTS•All criminal cases begin in magistrates’ courts where the case is introduced into the system.•Certain types of offences are known as indictable offences, these are serious offences and can only be heard in Crown Court. Other less serious summary offences are heard summarily in the magistrates’court.•Where an offence falls in between the two, it can be ‘triable either way’, the defendant will have the choice to be tried at the magistrates’ court or at the Crown Court.•Where the decision in a criminal case is appealled against, a court further up the hierarchy will hear it.•Appeals from magistrates’ courts are either to the Crown Court or the Queen’s Bench Division of the High Court.•Case stated appeals from the Crown Court are made to QBD. ‘Case stated’ is a legal function to review a magistrates’ court decision on a point of law , it means the law w as misinterpreted by the magistrate.•Appeals from the Crown Court are made to the Court of Appeal and this may be appealled to the Supreme Court for the United Kingdom if it involves an issue of publicinterests.4. THE MAIN CIVIL COURTS IN THE ENGLISH LEGAL SYSTEMMagistrates’ court•The magistrates’ court is mainly a criminal court, but it also has original jurisdiction in many civil cases, such as liscensing and family issues.•It will also hear claims for recovery of unpaid local authority charges and council tax(英国家庭税).County CourtCounty courts have civil jurisdiction only, it deal with almost every kind of civil case within its serve areas. The main limits to its jurisdiction are financial. It is involved in the following matters: •Contact and tort•Equity matters•Probate matters•Disputes concerning land•Undefended matrimonial cases•Some bankruptcy, company winding-up and admiralty cases（海事裁判）.High CourtThe High Court are divided into three divisions.•The Queen’s Bench Divison hears cases concerning contract and tort issues. It also hasa Commercial Court and an Admiralty Court. A divisionl court of the QBD has anappellate jurisdiction on appeals from magistrates’ court and tribunals.•The Family Division hears cases concerning children and matrimonial issues. The Family Division also has a limited appellate jurisdiction on some appeals from theMagistrates’ Court.•The Chancery Division hears cases concerning trusts, mortgage, bankruptcy, taxation, probate and corporate issures. It also has a Patents Court and a Company Court, which deals with liquidations and other company proceedings.Appeal courtsThe civil court which have an exclusively appellate jurisdiction are the Civil Division of the Court of Appeal and the Supreme Court for the United Kingdom.Court of Appeal•The Court of Appeal hears appeals from the County Court, High Court and several sepcial tribunals.•It reviews the evidence and the legal opinions and makes its decisions based on them.•Cases are heard by three judges ( known as Lord Justices of Appeal) who will decide the outcome by a majority..Supreme Court for the United Kingdom•The Supreme Court for the United Kingdom is the highest appeal court in the English legal system. Cases are heard by Justices of the Supreme Court.•The court hears appeals from the Court of Appeal and also appeals from the High Court, under the ‘leapfrog procedure’ .5. THREE TRACK SYSTEM FOR THE ALLOCATION OF CIVIL CASESThe Civil Procedure Rules (CPR 民事程序规定) introduced a three track system for the allocation of civil cases. Generally speaking, county courts hear small track cases and fast track cases and the High Court hears multi-track cases.•In the small claims track, claims of no more than £5,000 will be heard. These are cases to be dealt with quickly and informallly, often without the need for legal represetation or a full hearing. Parties can consent to use the small claims track if the value of the claimexceeds the limits, but this has to be subject to the court's approval.•In the fast claims track, claims under £25,000 may be heard. There is a strictly limited procedure designed to enable cases to be heard within a short but reasonable timescale.Costs are fixed and hearings are no longer than one day.•The multi-track is intended to provide a new and more flexible regime for the more complex claims, which has a value of more than £15,000. An initial ‘case managementconference’ will be held to encourage the parties to resolve the dispute or to consider the alternative dispute resolution. The trial judge sets a budget and a final timetable for thetrial.•Claimants of cases between £15,000 and £25,000 have the choice of using the fast or multi track, although judges may insist complex cases are heard under the multi track.Chapter 2 Sources of English lawSOURCESCase law Statute CustomCommon Equity Primary SecondarylawSources of English law•There are three main sources of English law, namely case law, legislation (statute) and custom.•Broadly speaking, case law is made and developed in the courts and legislation is made by the legislature（立法机关，立法团体） in Parliament.•Since both of these sources create law today, they can be considered as contemporary.•However, local customs, which developed historically and have existed for a very long time, are not considered as contemporary.1. CASE LAW AS A SOURCE OF LAW•Case law is is made in the courts according to the common law and equity.•Both common law and equity are the product of decisions in the courts made by judges who interpret and apply previous cases based on the doctrine of binding precedent.•This doctrine provides that once a principle of law has been decided, it becomes a precedent which binds the lower courts in cases with materially the same facts.•If the facts of the case are not materially the same as those of the relevant precedent, the precedent may be ‘distinguished’ and not be followed.•Only statements of law made by judges can form precedent.•These statements can be divided into ratio decidendi and obiter dicta.•Only the ratio decidendi forms the basis of precedent as it is this reasoning which is vital to his decision.•Obiter dicta are statements of general law (or hypothetical situations) which are not necessary for the decision and hence are not binding.•Whether the doctrine applies will depend on the status of the court dealing with the case.There is a hierarchy of courts with the lower courts being bound to follow thedecisions of the higher courts.•For example, magistrates’ courts and county courts are bound by the decision of the High Court, the Court of Appeal and the Supreme Court for the United Kingdom.2. DOCTRINE OF PRECEDENTThe doctrine of binding precedent•The doctrine of binding precedent, or stare decisis, is essential to the English legal system.•This doctrine provides that once a principle of law has been decided in court, it becomes a precedent which binds the lower courts in cases with materially the samefacts.•The purpose of the doctrine is to provide consistency, coherency and therefore predictablity and fairness in the development of the case law.Judgements• A judgement in a case will start with a description of the facts and probably a review of earlier precedents.•Then the judge will make statements of law applicable to the legal problems raised by the material facts.•These statements can be divided into ratio decidendi and obiter dicta.Ratio dicidendi•Only a proposition(论点，主张) of law, rather than a statement of fact, will be binding.•Ratio dicidendi can be difined as ‘any rule of law, express or implied, treated by a judge as a necessary step in reaching his conclusion, having regard to the line of reasoning adopted by him, or a necessary part of his direction to the jury. ‘ (Cross)Obiter dicta•Obiter dicta are statements of general law (or hypothetical situations) which are not necessary for the decision in the case.•The obiter dicta are of persusive authority only and do not bind lower court. They may be taken into account but need not be followed.Difference between them•The ratio decidendi forms the basis of precedent as it is this reasoning which is vital to judge’s decision.•It is not always easy to distinguish between the ratio decidendi and the obiter dicta.Judges do not always make clear in their comments whether a particular statement orconclusion is ratio or obiter. Indeed, in a case heard by more than one judge, each judge may provide a different ratio decidendi in support of a common decision.The hierarchy of the courts in relation to the operation of precedent(a) the Supreme Court for the United Kindom – binds all lower courts but itself(exceptional cases)(b) Court of Appeal–binds all lower courts and itself(c) High CourtJudge sitting alone – binds all lower courts not divisional courtsJudges sitting together – binds all lower courts and divisional courts(d) CrownMagistrates–bind no-one at allCountyMagistrates’, County and Crown Courts•Decisions of the Magistrates’ Courts and County Courts do not consititute precedent and thereofore not bind on any court, but each of them is bound by decisions of the High Court, Court of Appeal and the Supreme Court for the United Kingdom.•The Crown Court is also bound by the superior courts and its decisions are of persuasive authority only.High court• A decision of the High Court made by an individual judge binds all lower courts, but not another High Court judge. However, it is of persuasive authority and tends to befollowed in practice.• A decison of Divisional Court usually binds another divisional court.Court of Appeal•Decisions of the Court of Appeal binds all English courts except the Supreme Court for the United Kingdom.•The court is normally bound by its own previous majority and unanimous (意见一致的) decisions, and by those of the Supreme Court for the United Kingdom.The Supreme Court for the United Kingdom•The Supreme Court for the United Kingdom stands at the apex of the English judicial system. Its decisions binds all other English courts.•Itself is bound by its own previous decisions, but it reserves the rights to depart from its own precedents in exceptional cases, although this is rarely exercised.Reversing, overruling and distinguishingPrecedent• A precedent is a previous court decision which another court is bound to follow by deciding a subsequent case in the same way.•In certain circumstances, a judge may not wish to follow an previous decision and it may be open to them to reverse, overrule or distinguish the precedent.Reverse•When the decision of a lower court is appealled to a higher one, the higher court may reverse the decision if they feel the lower court has wrongly interpreted the law. Theoriginal decision cannot form a precedent.•For example, if the Court of Appeal reverse the decision of the High Court, the first decision cannot be a precedent but the reversed decision can.•When a decision is reversed, the higher court is usually also overruling the lower court’s statement of the law.Overrule•Higher courts may overrule the decisions of lower courts, depriving (剥夺) their precedent status, if they di sagree with the lower court’s statement of law.•Overruling involves an earlier case, rather than a case which is the subject of an appeal.•When a decision is overruled, the law is changed with retrospective effect. Judges are usually cautious before overruling a long-standing precedent, but this is sometimesnecessary, for example where what is acceptable within a particular society changes. Distinguishing•For a precedent to be followed, the facts of the previous case and the case under consideration must be materially the same.•If not, the precedent may be ‘distinguished’ and not followed.3. THE ADVANTAGES AND DISADVANTAGES OF THE DOCTRINEAdvantagesCertainty•Law is decided fairly and predictably.•The need for costly and time-consuming litigation can be avoided.•The doctrine also gives guidance to the judges and leads to consistency in decisions from different judges in different courts and in different parts of the country.Clarity•The doctrine gives rise to a healthy source of statements of legal principle that can helpfully and clearly be applied to new cases generally.•This leads to a saving of time for all concerned, it don’t need to be put before the courts and argued again.Flexibility•The doctrine allows the law to grow and be developed in accordance with changing needs and circumstances of society.•It also allows a much more flexible judge-made law than Parliament-enacted legislation. PracticalityFaineasDisvantages•Bulk.•Restricts judicial discretion.•reactive system.•Lack of democratic accountability.4. LEGISLATION AS A SOURCE OF LAW AND ITS ADVANTAGES•Statute law is made by Parliament.•Parliament may make law as it sees fit – it may repeal(撤销) earlier statutes, overrule case law or make law in new areas previously unregulated.•The validity of an Act of Parliament cannot be questioned. ( Cheney v Conn 1968).•However, this principle of Parliamentary sovereignty[ˈsɔvərɪnti:](最高统治权、君权) has been reduced somewhat by the UK’s membership of the European Union which requires its law to be brought into line with the EU’s treaties and directives.•Additionally, the Human Rights Act 1998 requires new laws to be compatible with the European Convention on Human Right.•Statute law may be fresh legislation or may be a consolidation of existing statutes and their amendment, for example the Company Act 2006.•It may also be a codification (法律汇编) of existing statute and case law, for example the Sale of Goods Act 1979.•The courts are bound to apply relevant statute law and cannot disregard or rewrite it.•Whatever the nature of the legislation, the role of judges to interpret and apply it is the same.•Judicial interpretation (司法解释) might be needed because of ambiguity in drafting or uncertainty as to whether a particular set of facts are within the scope of a statute, orwhere unforeseeable developments have occurred since the statute was passed.•The complexity of modern legislation makes a great deal of details which cannot be easily included in an Act.•Therefore, powers may be given to a minister or a public body to make laws for specified purpose in the form of statutory instruments, bye-law and Rules of Court.•Such delegated legislation has the same effect as the empowering act itself. Advantages•They can in theory deal with any problem•They are carefully constructed codes of law•New problems in society or unwelcome development can be dealt with quickly•Reponsive to public opinion as parliament is elected at least every five years5. DELEGATED LEGISLATION•The complexity of modern legislation makes a great deal of details which cannot be easily included in an Act.•Therefore, powers may be given to a minister or public body to make laws for specified purpose in the form of statutory instruments, bye-law and Rules of Court.•The legislation sets out the broad objective and purpose of the Act, leaving the detail to be delegated to individuals or bodies outside Parliament.•Such delegated legislation has the same effect as the empowering act itself.There are various forms of delegated legislation•Statutory instruments: these are made by government minister who has delegated the relevant powers.•Bye-laws: these are made by local authorities and apply within a specific locality•Rules of court: these may be made by the judiciary (法官) to control court procedure.•Orders in council: these are often made by the Privy Council (枢密院).•Professional rules: Parliament also gives powers to various professional bodies to regulate the conduct of its members.The control over the delegated legislationAs delegated legislation is often created by unelected individuals and bodies, there are controls over it.•It may have to be approved by an affirmative resolution of Parliament and/or be laid before Parliament for 40 days before it takes effect.•It may be challeged in the courts. Firstly, on the ground that Parliament exceeded its authority to delegate and has acted ultra vires, or secondly, the lagislation has beenmade without the correct procedure.•There are standing (永久的，常设的) Scrutiny Committees (检查委员会) of both Houses whose duty is to examine delegated legislation from a technical point of view and theymay raise objections if necessary. However, they have no authority to its nature orcontent.•The Human Rights Act 1998 gives courts power to strike out any delegated lagislation that runs contrary to the HRA.Advantages•Volume of work. Delegated lagislation enables Parliament to concentrate on the broader principles of the legislative framework, rather than getting bogged down indetails.•Speed. Delegated legislation enables new laws to be passed much more quickly, especially advantageous in times of emergency.•Flexibility. Delegated legislation enables great flexibility, because regulations can be altered later without the need to revert to (回到) Parliament.•Expertise. The subject of new legislation is often highly detailed, technical and complex. It therefore makes sense for the exact content, and the wording（措辞） isarrived at by consultation with professional, commercial or industrial groups outsideParliament who have the relevant expertise.•Tider primary legislation. The primary legislation is more concise (精炼) because the details are left to other delegated legislation documentation(程序说明书). Disadvantages:•Volume. The volume of delegated legislation means that it can become difficult for Parliment ( and others) to keep track of the effect of the legislation.•Unconstitutional.（违反宪法的) Although Parliament is ultimately responsible for the legislation, it is likely that much of the detail has actually been drafted and finalised by individual ministers or by civil servants. Since civil servants are unelected, the degree to which law-making powers should be delegated to them is a matter for some debate. 6. STATUTORY INTERPRETATIONLegislation must be interpreted correctly before judges can apply it fairly. In order to determine the meaning of such legislation, the court will apply a number of well-established rules and principles to interpret the statute.•Literal rule: The literal rule requires the words to be given their literal and grammatical meaning rather than what the judges think they mean.•Golden rule: The golden rule expands the literal rule. It requires the words to be given their plain, ordinary and literal meaning unless this would give rise to manifest (明显的) absurdity(谬论) or inconsistency with the rest of the statute.•Mischief rule: Under the mischief rule, a judges considers what mischief (损害) the Act .Where a statute is designed to remedy a weakness in the law, the correct interpretation is the one that achieves it.•Purposive approach : It requires the words to be given not only their ordinary, literal and grammatical meaning, but also with reference to the context and purpose of thelegislation.•Ejusdem generis (同类) : Where general words follow specific words, the general words must be interpreted by reference to(参考) the specific words used.7. HUMAN RIGHTS ACT 1998The Articles of the European Convention on Human Rights have now been enshrined(铭记) into English law as the Human Right Act 1998, enacted in 2000. The main provisions are: •The right to life•The right to property•The right to education•The right to marry•The right to a fair trial•The right to liberty and security•The right to free elections.•The right to respect for privacy, family life•Freedom of thought, conscience and religion•Freedom of expression, assembly and association•No punishment without law•No discrimination in rightsThe Act binds the pubilc authorities•The Act binds the pubilc authorities, which can be defined as bodies undertaking functions of a public nature, including government departments, local authorities, courts and schools.Non-government individuals or bodies can rely on the actImpact on UK law•The main impact of the HRA1998 on UK law is that UK courts are now required to interpret UK law in a way that is compatible with the Convention. It means that a courtmust take into account the previous decisions of the European Court of Human Rights.•If a court feels that a provision of primary legislation ( ie an Act of Parliament) is incompatible with the Convention, it can make a declaration of incompatibility. It is thenup to the Government to take action to remedy the incompatibility.Chapter 3 Offer and AcceptanceNature of a contractFORMATION & NATURE OF A CONTRACTAgreement Intention ConsiderationThe first essential element in the formation of a binding contract is agreement. This is ususlly evidenced by offer and acceptance.1. OFFER•In the law of contract , an offer is a definite promise to another to be bound on specific terms. It is capable of (能够) acceptance so as to form a binding contract.•An offer cannot be in vague terms, for example a promise to buy a horse if it is ‘lucky’ (Gunthing v Lynn 1831).•An offer can be made to an induvidual, a class of persons or to the world at large and it can be accepted by the conduct of the offeree ( Carlill v Carbolic Smoke Ball Co 1893).•Once an offer has been accepted, a binding contract is created. Either party may legally enforce the promise of the other.•Ture offers must be distinguished from a mere supply of information and statement of intention.Supply of information• A mere supply of information is not an offer, because there is no intention to be bound.•For example, stating the minimum price that one would consider if a sale were to be agreed does not make an offer ( Harvey v Facey 1893).Statement of intention•Similarly, a mere statement of intention is not an offer neither.•For example, advertising that an event such as an auction will take place does not make an offer. (Harris v Nickerson 1873).•Only the offer made with the intention that it shall become binding when accepted may form a binding contract.2. INVITATION TO TREAT•An invitation to treat is an indication that someone is prepared to receive offers with the intention to form a binding contract.•There is no binding contract until this offer is made and, in turn , accepted.Case law has established a number of accepted principles to determine whether a statement is an offer or merely an invitation to treat.Advertisements•An advertisement of goods for sale is usually an attempt to induce offers (Partridge v Crittenden 1968)•However, in limited circumstances, words of an advertisement can be an offer made to the whole world (Carlill v Carbolic Smoke Ball Co. 1893)Display of goods in a shop window•In Fisher v Bell 1961, a shopkeeper was prosecuted for offering for sale an offensive weapon by exhibiting a flick knife in the shop window.•It was held that this was not an offer for sale, but an invitation to treatExhibitions of goods in a self –service shop•In Pharmaceutical Society of G.B. v Boots Cash Chemists 1952, the chemists exhibited various goods on self-service shelves.•It was held that this was not an offer for sale, but an invitation to treat. Customers took up the invitation by taking the goods to the cash point, thereby making an offer to buy which was accepted by the shopkeeper.Auction sales（拍卖）•An auctioneer’s request for bid is not an offer to sell to the highest bidder, but an invitation to treat.•The bid itself is an offer, which the auctioneer is then free to accept or reject ( Payne v Cave 1789).Invitations for tenders (竞标)•An invitation to tender is not an offer to contract with the party offering the lowest price, but an invitation to treat.•The tender itself is an offer, which the person who issued the invitation is then free to accept or reject.3. ACCEPTANCE OF AN OFFERACCEPTANCE•Valid acceptance of a valid offer is one of the essencials of a contract•An acceptance must be an unqualified (无条件的) agreement to the terms of the offer.•Acceptance is generally not effective until communicated to the offeror, except where the ‘postal rule’ applies.• A purported acceptance which introduces any new terms is a counter-offer, which has the effect of terminating the original offer ( Hyde v Wrench 1840).Request for information• A response to an offer which is actually a request for further information will not form an acceptance.Acceptance ‘ subject to contract’•Acceptance ‘ subject to contract’ means tha t the offeree is agreeable to the terms of the offer but proposes that the parties should negotiate a formal contract.•Neither party is bound until the formal contract is signed.Letters of intent (LOI 合作意向书)• A letter of intent is a strong indication given by one party to another to say that he is likely to place a contract with him.Method of acceptance•The acceptance of an offer is made by a person authorised to do so, usually the offeree or his authorised agent.•The acceptance may be by express words or be inferred from conduct (Brogden v Metropolitan Rly Co 1877).•In some circumstance (Carlill v Carbolic Smoke Ball Co 1893), performance of the act required by the offer or advertisement consititutes an acceptacne.•There must be some act on the part of the offeree since passive inaction or silence is not capable of acceptance ( Felthose v Bindley 1862).The communication of acceptance•Acceptance is generally not effective until communicated to the offeror, except where the ‘postal rule’ applies, or t he offeror waives the need for communication.•The offeror may specify the sole means of communication, in which case only compliance with their terms will suffice （满足……的需要）.•If the offeror specifies a means of communication but does not make it absolutely compulsory, then acceptance by another means which is equally expeditious and does。

保险学重点

1.哈雷生命表编制为计算费率提供不同年龄层…..死亡率、生存率
2.风险分类：经济、自然……
3.保险合同的客体
4.投保单存在告知不实问题、合同效力？中止、有效、暂缓、执行？
5.保险产品中强制性保险是哪一个？
6.保险原则中损失补偿原则：保险金额不超过什么？
否则超过部分无效
7.如实告知义务的原则——询问告知P60
8.保险人、保险合同寻求代位追偿之后，得到金额大于实际赔偿金额后，超过部分归谁？
9.船舶保险、海上货物保险、海上保险的区别？
10.45岁健康终生
限时
夯交
缴费至65岁
关于每次缴费金额从大到小排列——ppt上面找
11.海上货物运输险中：平安险、一切险、水渍险的保险责任范围？
12.非寿险业务中未到期责任准备金提取方式？按什么保费的多少比例提取？
按当年自留保费的50%提取
13.万能保险死亡给付方式相同时，现金价值减少时，经营风险怎样变化、净风险保额
14.保险标的保险价值<保险金额时，标的发生全损，按哪种支付？
15.保险基金属于社会储备基金的一种
国家财政or地方财政统一建立的货币基金是什么基金？
多选题：
1.保险合同的关系人
2.保险费率由什么构成？
3.保险投资工具主要有哪些
4.人身保险、财产保险的区别
5.保险合同的解释方法：文义、意图、补充解释
6.财产损失保险赔偿处理的程序
7.火灾保险的除外风险（除外不保）
8职业责任险的险种？
9.年金保险的分类（按不同方式分类）
10.分红保险的主要红利来源：
案例分析：
四大基本原则
人寿保险中9大附加条款。

IC Manufacturing and Yield

Variability reduction is accomplished by strict process control.
Production Efficiency
Determined by actions
both on and off the
manufacturing floor
Process Design
Solution:
For the
x
-chart:
UCL x 3s c4 n
4.14mm
LCL x 3s 3.88mm
c4 n
Example
Solution (cont.):
For the s-chart:
UCL s 3 s c4
1 c42 0.19mm
LCL s 3 s c4
constant size is modeled by Poisson distribution, in which the probability of a defect occurring is
P(x) eccx x!
where x is the number of defects and c > 0
Control Charts for Variables
In many cases, quality characteristics are expressed as specific numerical measurements.
Example: the thickness of a film. In these cases, control charts for variables
where the grand average is: x x1 x2 xm m

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Received 9 July 2001; revised and accepted 26 November 2001
Abstract The effect of static misalignment on the dynamic behaviour of a main crankshaft bearing is examined in this paper. The mobility method of Booker is used to predict the performance parameters of the bearing such as the minimum oil-ﬁlm thickness and the journal centre cyclic path under dynamic load conditions. The theoretical results are compared with those of an aligned bearing. The Ruston–Hornsby 6 Veb-X Mk III engine big-end bearing is selected as an example to validate the computer program incorporating the present analysis. It is shown that the misalignment has signiﬁcant effects on the minimum ﬁlm thickness and the journal centre trajectories even for the low values of misalignment parameters. It is also found that the presence of circumferential feed grooves can cause metal-to-metal contact in such bearings. 2002 Éditions scientiﬁques et médicales Elsevier SAS. All rights reserved.
a Mechanical Engineering Department, Guelma University, B.P. 401 Guelma 24000, Algeria b Solid Mechanics Laboratory, URA-CNRS, University of Poitiers, France
1. Introduction The design of internal combustion engine crankshaft bearings considering the misalignment phenomenon is a complex problem because it requires, not only the knowledge of the bearing loads, but also the determination of the misalignment parameters (α and γ ). In such bearings, the misalignment is essentially due to the elastic deﬂection of the crankshaft which is subjected to important gas and inertia forces. In practical applications, the bearing loads as well as misalignment parameters vary both in magnitude and direction during an engine cycle. This problem is important in the industrial environment because the malfunction of engine bearings may cause severe mechanical failures, generally in the crankshaft, which will then need costly repairs. Due to the complexity of this problem, a few number of studies have been carried out taking into account a dynamic loading, most of them dealing with the steady load case. The ﬁrst experimental study was published by S.A. Mc Kee and J.R. Mc Kee (1932) who observed that in the case of eccentric loading the peak pressure location moves away from the axial centre of the bearing involving a misalignment torque. In 1950, an analytical approach permitting to determine the pressure distribution in a misaligned journal bearing was proposed by Walther and Sassenfeld (1950). Seven years later Dubois et al. (1953) investigated experimentally the inﬂuence of misalignment defect on the performance characteristics of a journal bearing. Smalley and Mc Callion (1966) showed the effect of journal misalignment on the performance of a full journal bearing lubricated with Newtonian lubricants for aspect ratios of 0.5 and 0.75 under steady running conditions. Asanabe et al. (1972) conducted a theoretical and experimental investigations of a grooved bearing under misalignment and steady load, but, only considered misalignment in the vertical plane. In 1972, the same investigation have been made by Nicolas (1972). The axial supply groove was located at the maximum ﬁlm thickness in the mid-plane bearing section. Pinkus and Bupara (1979) presented an exhaustive analysis of an axial grooved journal bearing. The results obtained were published in the form of plots and tables. Mokhtar et al. (1985) gave an adiabatic solution of misaligned journal bearings with both axial and spiral feeding. Bousaid and Chaomleffel (1987) presented the inﬂuence of misalignment parameters on dynamic characteristics of three asymmetric lobed bearings for two values of eccentricity ratio ε0 = 0.2 and 0.8. they demonstrated that the inﬂuence of misalignment is important at lower eccentricity ratios particularly when the degree of misalignment exceeds 60%. Safar et al. (1989) analysed the static performance characteristics for misaligned journal bearings operating in turbulent regime. Results showed that misalignment has signiﬁcant effect on the bearing performance characteristics especially at lower eccentricity ratios. Also, they found that the effect of misalignment directional angle is almost negligible. Vijayaraghavan and Keith (1990) analyse a ﬁnite grooved misaligned journal bearing considering cavitation and starvation effects. The modiﬁed Elrod cavitation algorithm was used to predict the location of the ﬁlm rupture and reformation fronts. From the analysis, the authors showed that for higher degrees of misalignment, the performance characteristics of the bearing differ greatly from those predicted in the case of an aligned journal bearing. In all of the above theoretical and experimental studies, the authors considered only the steadily loaded journal bearings case. Many investigators have selected the big-end bearing of a Ruston Hornsby engine for their studies and to compare the theoretical results. It is difﬁcult to list all these publications in this paper but a good survey has been presented in the review papers by Campbell et al. (1967) and Martin (1982). The speciﬁc research work published in the case of a dynamic loading was that of Goenka (1984). The author studied a misaligned big-end connecting-rod bearing using a ﬁnite element technique. Misalignment was supposed constant and perpendicular to the rod axis. Singh and Sinhasan (1988) studied the effects of small misalignment on the dynamic characteristics of an ungrooved bigend bearing. To obtain the hydrodynamic pressure, the Galerkin’s ﬁnite element approach was used to solve the Navier–Stokes equations for the ﬂow ﬁeld in the clearance space of the bearing. The Ruston and Hornsby engine was selected as an example for calculation and comparison of results. The authors found that the value of minimum oil-ﬁlm thickness is about 28 percent smaller than that obtained in the parallel axes bearing case.