Controlled net shape, density and microstructure of TiC-NiTi cermets using quasi-isostatic pressing

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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。

半导体一些术语的中英文对照

半导体一些术语的中英文对照离子注入机ion implanterLSS理论Lindhand Scharff and Schiott theory 又称“林汉德-斯卡夫—斯高特理论"。

沟道效应channeling effect射程分布range distribution深度分布depth distribution投影射程projected range阻止距离stopping distance阻止本领stopping power标准阻止截面standard stopping cross section 退火annealing激活能activation energy等温退火isothermal annealing激光退火laser annealing应力感生缺陷stress—induced defect择优取向preferred orientation制版工艺mask—making technology图形畸变pattern distortion初缩first minification精缩final minification母版master mask铬版chromium plate干版dry plate乳胶版emulsion plate透明版see—through plate高分辨率版high resolution plate，HRP超微粒干版plate for ultra-microminiaturization 掩模mask掩模对准mask alignment对准精度alignment precision光刻胶photoresist又称“光致抗蚀剂"。

负性光刻胶negative photoresist正性光刻胶positive photoresist无机光刻胶inorganic resist多层光刻胶multilevel resist电子束光刻胶electron beam resistX射线光刻胶X-ray resist刷洗scrubbing甩胶spinning涂胶photoresist coating后烘postbaking光刻photolithographyX射线光刻X—ray lithography电子束光刻electron beam lithography离子束光刻ion beam lithography深紫外光刻deep—UV lithography光刻机mask aligner投影光刻机projection mask aligner曝光exposure接触式曝光法contact exposure method接近式曝光法proximity exposure method光学投影曝光法optical projection exposure method 电子束曝光系统electron beam exposure system分步重复系统step—and—repeat system显影development线宽linewidth去胶stripping of photoresist氧化去胶removing of photoresist by oxidation等离子[体］去胶removing of photoresist by plasma 刻蚀etching干法刻蚀dry etching反应离子刻蚀reactive ion etching，RIE各向同性刻蚀isotropic etching各向异性刻蚀anisotropic etching反应溅射刻蚀reactive sputter etching离子铣ion beam milling又称“离子磨削”。

MSpec 辐射探测仪说明书

A D V A N C E D T E C H N O L O G Y F O R A S A F E R W O R L DM S pec with protective bootMSpecGamma & Gamma/NeutronHandheld SpectrometerLocate and Identify Specific IsotopesThe MSpec is palm sized gamma ray spectrometer that utilizes a Sodium doped Cesium Iodide Crystal with high signal to noise ratio PMT and state-of-the-art electronics for the most accurate results. The MSpec scans suspect material and quickly analyzes to determine what nuclide isotope is present and then calorizes the result as Medical, Industrial, Natural Occurring Radioactive Material (NORM), or Special Nuclear Material (SNM).User FriendlyThe MSpec has two modes a user may choose from: Manual or Automatic. Automatic is the quickest and easiest to use mode. Set in Automatic the MSpec will search for and detect radioactive material. Once in range the instrument will automatically begin isotopic identification and display the results. Manual mode gives the user greater control including the ability for longer scan times which increases the accuracy of results. This is especially important if there are multiple isotopes present in the same sample.RadView SoftwareR adComm’s exclusive RadView software interfaces with a user’s PC and enables a user to see detailed results of recorded scans in a Histogram format. Each result can be edited with comments, saved as a PDF and archived for future reference or email compatibility.LAURUS Systems, Inc. - Ph: 410-465-5558 - Fax: 410-465-5257 - LAURUS Systems, Inc. - Ph: 410-465-5558 - Fax: 410-465-5257 - RadView PC Software Program for Data ManagementMECHANICAL∙ Rugged Case: 4.75” x 2.5” x 1.22” (12 cm x 6.4cm x 3.1cm) ∙ Display Window : 1.56” x 1.81” (3.96cm x 4.6cm) ∙ Weight : 0.44lbs (200g)∙ Five Push Button Actuation Mini USB Connector for Internal Battery Charging∙ Operating Temperature Range: 14ºF to +113ºF (-10°C to +45ºC) ∙ Thru-hole for Audio Alarm∙Shock resistance – 1 meter drop test ELECTRICAL∙ Micro-Controller Based Architecture ∙ 1.56” x 1.81” (3.96cm x 4.6cm) LCD with Backlight∙ Backlight Auto-Off (180 seconds) with Push Button Auto-On ∙ Audio Alarm with Vibration∙ Stable Low Noise H.V. Power Supply∙ Internal Rechargeable Li Ion Battery with Charging LED indicator ∙ Battery Life: 6 hours continuous with Backlight∙Battery Recharge Time: 4.5 hours based on 2400mAh BatterySOFTWARE∙ Menu Driven User Interface∙ Menu Feature Selection Controlled by a Five Push Button Actuation ∙ Storage of 300 spectra, resettable and downloadable via USB∙ Selectable Features: Date and Time, Units of Measure, Readings Update, Language ∙ PC Configurable∙ Up to 6 Digit Auto-Scaling Displayed Radiation Level ∙ Selectable Displayed Units - CPS, R/hr, Sv/hr∙ Base Sampling Rate is 200 mSec, Screen Updates Every 1/Second (CPS)∙ Battery Level Indicator: Three Bars for Full Battery, Low Battery Warning Message with the battery bar flashing, 10% Battery Capacity Remaining Audio Beep Every One Minute, System will Turn Off at 5% Battery Capacity∙Warning Messages: Move Closer; Move Away, CPS Exceeds Threshold, Stabilization Off. No ID, Stabilization Required, Memory is Full, ScanningDETECTOR Gamma∙ CsI(Na) Crystal: 0.5” X 1.5” (13mm X 38mm) ∙ Energy Range: 20 KeV – 3.0 MeV∙ Dose Rate Range: 1 μR/hr to 1 R/hr (0.01μSv/hr to 10.0 mSv/hr) ∙ Gamma Sensitivity: Cs137 1,300 (cps/mR/hr) ∙ Gamma Spectrum: 1024 Channels ∙ Resolution: 9% or better at 662 KeV∙ Optional Neutron Detector; 4.5 cm³ He3, Sensitivity - .6 cps per /NV ∙ Accumulated Dose: 1000 R (10 Sv), resettable ∙Radiation Warning Level: 1.14 mR/hr (10.0 μSv/hr)Neutron∙ Neutron He3 Tube ∙ High Density Moderator∙ High Gain with High Signal to Noise Ratio Amplifier ∙ Mechanical Noise rejection Circuitry∙Neutron Software Option for the MSpec and the PC SoftwareSPECIFICATIONSMSpecReal Time Spectrum Display。

表面和界面-Surfaces and Interfaces

8. Surfaces and Interfaces8.1 IntroductionThere exist differences in the important parameters describing interfaces and surfaces:Surfaces Interfacesroughness composition conformation chain ends width (roughness) profile conformation fluctuationssnapshot of a coarse-grained moleculardynamics simulation of a block co-polymer double bilayer in waterGoundla Srinivas, IBM Almaden Research Centerthermodynamic: To allow contact between two different phases, an interface with a free energy between them is needed. Across this interface the intensive properties of the systems are changing from one phase to the other.Free energy of the interface ΔG = ΔW = 2σAA change of the interface requires a free energy ΔG, meaning a work ΔW, proportional to the area A and interfacial tension σ, is needed.work of cohesion W c = 2σwork of adhesion W c= σ1+σ2-σ12The process is assumed to be fully reversible.8.2 Polymer Surfaceair / vacuumpolymer surfacepolymer volume (bulk)Simple microscopic view: attractive forces between the atoms (spring-bead model) with force equilibrium in the volume, but missing partners at the surface→ attraction oriented towards the bulk→ surface tension / surface energy→ change of the structure at surfacea) Chain conformation in the vicinity of the surfaceComputer simulation: Structural properties of a dense polymer melt confined between two hard walls are investigated over a wide range of temperatures by dynamic Monte Carlo simulation using the bondfluctuation lattice model.The effect is present in a region close to the polymer surface. Deviation of the chain conformation is found in a region with an extension of ≈2R g .Baschnagel, Binder, Macromolecules 28, 6808 (1995)As the wall is further approached, the ability of the chains to reorient is progressively hindered, leading to an increase of R g|| and to a decrease of R g ⊥. Therefore the main effect of the wall is to reduce the orientational entropy of the polymers and to align them preferentially parallel to it.Experiments (GISANS): The samples consist of blend films of protonated and deuterated polystyrene (PS) spin coated onto glass substrates. A variation of the thickness of the blend films in a range of about 41 down to 0.66 times the radius of gyration R g of the chains in the bulk enables the determination of film thickness and confinement effects with the advanced scattering technique grazing incidence small angle neutron scattering (GISANS).The effect of the breaking of the translation symmetry by the presence of a surface is found in a more extended region of ≈8R g .Kraus et al., Europhys. Lett. 49, 210 (2000)The polymer molecule is altered in its conformation from an isotropic Gaussian chain (sphere) into an ellipsoidal shapechain segments are oriented in parallel to surfaceb) Chain end distribution Theory:Density of chain ends at the surface (de Gennes, 1992):φφρee N 2=with N length of chainφe number of ends at surfaceφ number of monomers per volume→ chain ends from a region 2R g are enriched in a layer of thickness d (typically 1-2 nm):N dae 2=ρ with segmental length aenrichment of chain ends at the surface due to entropic effects Experiments (NR): Mono-terminated polystyrenes (PS) are synthesized anionically to include a short perdeuteriostyrene sequence adjacent to the end groups for the purpose of selective contrast labeling of the end groups for neutron reflectivity (NR).The location of deuterium serves as a marker to indicate the location of the adjacent end group. Damped oscillatory end group concentration depth profiles at both the air and substrate interfaces are found. The periods of these oscillations correspond approximately to the polymer chain dimensions.contrast density depth profileKoberstein et al; Macromolecules 27,5341 (1994)c) Segment distribution in the vicinity of surfaceComputer simulation: Strong orientation of segments due to the breaking of the translational symmetry of the system by the presence of a surface. The effect is present in region close to surface only, with extension of ≈2R g.Experiments (Force balance): Strong modulation in the density in the vicinity of the surface (effect much more pronounced in case of a solid wall).transition region with significantly decreased densityd) Influence on the kineticsComputer simulation:At the polymer surface a very mobileand quasi-liquid layer is existing wellbelow a melting temperature T m. In thislayer the chain mobility is increased.at surface mobility in movement in parallel to the surface is increased in a thinlayer of thickness d (typically 2 nm)This behavior is similar to many crystal samples. The origin is the reduced number of entanglements at the surface.Experiments (FCS): Comparison of polymer diffusion, polyethyleneglycol (PEG), when adsorbed to a solid surface and in free solution(a) Flexible polymer chains that adsorb are nearly flat at dilute surface coverage (i.e., de Gennes pancake). The sticking energy for each segment is small, so no single segment is bound tightly, but the molecular sticking energy is large. (b) Diffusion coefficients (D) in dilute solution (blue circles) and at dilute coverage on a solid surface (red squares) plotted against the degree of polymerization (N) at 22°C.on surface: changed power law due to excluded volume statisticsDepending on the interaction between polymer and wall the mobility can by unchanged to bulk (neutral wall) or slowed down (attractive wall).How do polymer surfaces look in experiments?Examples:polystyrene machined titanium dual-acid-etched (DAE)titaniumSEMAFMNakamura et al, JDR 84, 515 (2005)Typically polymer surfaces are significantly smoother as compared to metal and metal oxide surfaces (independent of the surface treatment).PMDEGA after swelling in water vapor after 6 days storage in airZhong, PMB et al, Colloid. Polym. Sci. 289, 569 (2011)Homopolymer surfaces are only smooth with low surface roughness and good homogeneity if the homopolymer film is stable. If it is unstable the surface can roughen.If the polymer crystallizes a completely different polymer surface is observed. Due to the crystals present at the polymer surface, the surface roughness is significantly increased.8.3 Interface between polymerscase I: identical polymers A/A or compatible polymers A/B• interdiffusion of segments • adhesion • model of segment movementexample: PS/PS, PMMA/PMMA, PMMA/PVCcase II: incompatible polymers A/B• width of the interface in equilibrium • polymer-polymer interaction parameter (Flory-Huggins parameter) χexample: PS/PBrS, PS/PMMA, PS/PpMS, PS/PnBMAMathematical description of the interface:Rough interface j with mean z-coordinate set to zero and fluctuations in height z j (x)The rough interface can be replaced by an ensemble of smooth interfaces weighted by a probability density P j (φ)with a mean value ∫=dz z zP j j )(μand root-mean-square (rms) roughness ()∫−=dz z P z j j j )(22μσDifferent probability density function are possible and result in different interfaces: Normalized error-function (solid line) and hyperbolic-tangent (dashed line) have very similar refractive index profiles n j (z).Error function profile⎟⎟⎠⎞⎜⎜⎝⎛−−−+=++j j j j j j j z z erf n n n n z n σ222)(11 results from Gaussian probability density (μi =0) ⎟⎟⎠⎞⎜⎜⎝⎛−=222exp 21)(j jj z z P σσπand hyperbolic-tangent profile ⎟⎟⎠⎞⎜⎜⎝⎛−−−+=++j j j j j j j z z n n n n z n σπ32tanh 22)(11results from probability density (μi =0) ⎟⎟⎠⎞⎜⎜⎝⎛=−j jj z z P σπσπ32cosh 34)(2Both examples are based on symmetric probability functions, however, for real samples this symmetry is not ensured and thus asymmetric profiles can occur (e.g. polymer brush with exponential decay).a) Interface width of polymer interfacesComputer simulation (Monte-Carlo simulation by Binder, 1994):A symmetric binary mixture (polymer1, polymer2) below its critical temperature T c of unmixing is considered in a thin-film geometry confined between two parallel walls, where it is assumed that one wall prefers polymer1 and the other wall prefers polymer2. Then an interface between the coexisting unmixed phases is stabilized.with interface width χ6a L = yields rms-roughness πσ2L rms =only valid for smooth interfaces (σrmssmall) with qR g >1 and N →∞with segment length a scattering vector ()dq πλπ2sin 4=Θ=Not taking into account: - concentration dependence of χDifferent approximations in the framework of Mean Field theories:• Binder: expansion of free energy for φ=0.5 and N 1=N 2=N (with qR g >1 and χN>>1)()NaL 26−=χ• Brosetta: Integration of the quadratic gradient term in the vicinity of φ=0.5⎟⎠⎞⎜⎝⎛⎥⎦⎤⎢⎣⎡+−=21112ln 26N N aL χ• Stamm: minimization of the free energy using a "trial"-function⎟⎟⎠⎞⎜⎜⎝⎛⎥⎦⎤⎢⎣⎡+−=2121166N N aL πχ ⇒ It is possible to determine the polymer-polymer interaction parameter χ froma measurement of the interface width L, in case the degree of polymerization Nand the segment length a are known!• Frisch: modification of the profile on different length scales: deviation from the simple tanh-shapeb) entanglement density at the interface between two immiscible polymers The variation of entanglement density with interface width at an interface between two polymers is calculated using the relationships between chain packing and entanglement. The chain packing is obtained by the use of self-consistent mean-field techniques to calculate the average chain conformations within the interface region.calculated number of segmentsbetween entanglements as a functionof χassuming a bulk value of N e,typical for polystyrene, of 130Oslanec and Brown, Macromolecules 36, 5839 (2003)b) time dependent evolution of the interface widthHowever, all these models describe a time average and the final equilibrium interface. With experimental techniques it is possible to prepare interface between polymers far from equilibrium and to follow changes with time resolution.covering a large range of time and length scales the crossover between 4different regimes is observedt < τe: Rouse regimeτe < t < τf: Reptation regimeτf < t < τd: Blob movementτd < t: Fick diffusioncharacteristic power laws: tαRouse regime: α = 0.5Reptation regime: α = 0.25Fick Diffusion: α= 1.08.4 Rouse Model(P.E.Rouse 1953, extension B. Zimm 1956)The Rouse model describes the conformational dynamics of ideal chains. The main assumptions are: 1. no excluded volume interaction2. no hydrodynamic interactionTherefore one expects this model to work at Θ-condition or polymer melt condition.Polymers are interconnected objects with a large conformational entropy. As a consequence, the universal entropy-driven Rouse dynamics prevails at intermediate scales, where local potentials have ceased to be important and entanglements are not yet active. Key signature of the Rouse motion is the sublinear evolution of the segmental mean-square displacement2)(t2/1tr≈neutron spin echo (NSE) results on the single-chain dynamic structure factor: dynamics of poly(vinyl ethylene) on length scales covering Rouse dynamicsMean-square displacementof the protons, the solid linerepresents Rouse dynamicsRicher et al., Europhys. Lett., 66, 239(2004)Both molecular-dynamics (MD) simulations and MCT calculations on coarse-grained polymer models (bead and spring models)Bead-spring modelIn this model of a polymer molecule it consists of beads and springs forming a chain. The beads are hydrodynamics resistance sites that are dragged on by the suspending fluid. They also experience random Brownian forces caused by the thermal fluctuations in the fluid which are significant on the molecular scale. The spring is an entropic force pulling the adjacent beads together. In fact, the spring represents many monomer units that can coil and uncoil in response to the forces. This model is a reasonable representation of the polymer chain dynamics that actual polymer molecules undergo.8.5 Reptation Model(de Gennes, Doi, Edwards, 1971 + 1978)Reptation is the snake-like thermal motion of very long linear, entangled macromolecules in polymer melts or concentrated polymer solutions. It comprises:• entanglements with other chains hinder diffusion• each polymer chain is envisioned as occupying a tube of length L • movement of polymer chain is only possible within this fictive tube• special type of movement: diffusion only via movement of chain ends,keeping chain conformation unchangedtube diameter ddifferent types of movement:t < τe : no hindering in movement by tube (Rouse type movement)t = τe : density fluctuations within the chain are extended up to the length scale of the tube diameterτe < t < τf : polymer chain moves along the tubeτf < t < τd : chain starts to escape the tubet = τd : chain left the original tubet > τd : completely free movement of the chain with no remembering of the tubeExample:PE M w = 190k d = 49Å or PE M w = 17k d = 54ÅPS d ≈ 50ÅN R e , density ρ und temperature TInfluence on the interface profile:shown for different relative diffusion times t/t f 0.1 s mall →0.9 largeThe jump in the concentration profile is caused by the movement of the chain ends across the interface in the framework of the Reptation model.Attention: the profile needs to be convoluted with the tube diameter d8.6 Fick diffusionTranslation of the complete polymer chain is described as diffusion of the centerof masswith diffusion coefficient D Attention: different diffusion coefficients are existing D S self-diffusion coefficient (A moves in a matrix of A) D I inter-diffusions coefficient (A und B move with respect to each other) D T tracer-diffusion coefficient (marker T moves in matrix A)a) self-diffusion:Movement of chains in the identical environment → very difficult to detect experimentally, because no contrast between chain and environmentPossibility of marking individual chains (by deuteration or with fluorescent end-groups), but strictly this is a tracer experiment already Example: PS volume D S ≈4*10-14 cm 2/s thin film (300Å) D S ≈1.5*10-15 cm 2/s surface D S ≈9.3*10-16 cm 2/s⇒ slowing down of the diffusion due to the spatial confinementb) inter-diffusion:An interface between two polymers, which was prepared out of equilibrium (e.g. with the floating technique) is annealed above the glass transition temperature of both polymers→ broadening of the interface following the above arguments → late stages are caused by diffusion (t > τd )Experiment: X-ray- or neutron reflectivity measurementshydrogenated and deuterated polystyrene has been measured at 115 °C in-situ and in real time using NRdiffusion coefficientD = (1.7±0.2) × 10-17 cm 2/sBucknall et al., Macromolecules 32, 5453 (1999)• "fast-mode" theory B T B A A T A B I D N D N D ,,φφ+= • "slow-mode" theoryB T B A A T A B I D N D N D ,,111φφ+=Examples:Low molecular weight liquids D ≈10-6 cm 2/s polymers D ≈10-12-10-17 cm 2/s depending on temperaturec) tracer-diffusionusing small markers, e.g gold atoms in a well defined layered approachAnnealing the sample above the glass transition temperature of the polymer and probing the distances which the gold atoms had moved after defined times tReiter et al. Macromolecules 24, 1179 (1991)Dependence on molecular weight:Stamm et al., Macromolecules, 26, 2134 (1993)tracer-diffusions constant2−∝W T M D8.7 additional contributions to the interface widthIn addition to the width of the interface between two polymers which results from interdiffusion, contribution from other sources have to be taken into account. They arise from preparation: thickness variation of the filmwrinkles, dust particles, holes, impuritiesintrinsic: capillary wavesA capillary wave is a wave traveling along the phase boundary of a fluid, whose dynamics are dominated by the effects of surface tension. These waves are of thermal origin .Assuming a semi-infinite liquid with surface tension γLV a complex movement of the atoms makes a surface wavehaving a dispersion relation()g q q q LV rr r +=ργω32with ρ liquid density g Earth's accelerationSo thermal fluctuations cause a deviation from the ideal flat surface with an excess free energy density()()()()()Ζ⎥⎦⎤⎢⎣⎡ΖΔ+⎟⎠⎞⎜⎝⎛−Ζ∇+=Ζ∫∫22111d l P h A h fA L LV L exr r r γ ()()()()()Ζ⎥⎦⎤⎢⎣⎡Ζ+Ζ∇≈Ζ∫∫221d h P h A h f A L L LV L ex r r r γ yielding the height-height-autocorrelation function and power spectral density()Ζ=Ζr r c LV B q K Tk C 02)(πγ and 22214)(c LV LV B q q T k q L γγπ+=rwith K 0 modified Bessel function of zero ordercapillary waves can only be excited in an interval between λmin and λc for T>>0KA gravitation cut-off of the larges possible wavelength being excited isc c q πλ2=with LVc g q γρ=2 with the capillary length gLVργξ=being the lateral correlation length characteristic for the liquid (on the order of mm)and a short-range cut-off on the scale of the molecule diameter a is needed to avoid divergence of C(Ζ)a q 22maxmin ==πλ with a q π=maxExample: ethanol-vapor interface, σ=6.9 Åx-ray reflectivity and longitudinal diffuse scattering x-ray transverse diffuse scatteringSanyal et al.; Phys. Rev. Lett. 66, 628 (1991)Attention: in case of interfaces instead of surfaces the surface tension γLV is replaced by the interface tension γLL which is orders of magnitude smaller than the surface tension→ contribution of capillary waves to rms-roughness of interface increasedExample: Direct visual observation of thermal capillary waves at the free liquid-gas interface in a phase-separated colloid-polymer mixture imaged with laser scanning confocal microscopy (LSCM) at four different state points approaching the critical point(2004) each image is 17.5 μm by 85 μmAarts et al. Science 304,847Simple liquid → polymer:For highly viscous liquids and polymer melts the capillary waves are overdamped, their amplitude reduced.While, in general, both damped and propagating modes exist, for highly viscous polymers all modes are overdamped, which can be characterized solely by relaxation times τ.physical meaning of the over-damped relaxation timeconstantSinha, University of CaliforniaRoughness measurements are time averaged and cannot reveal the dynamic behavior of the waves.→ Need to probe the dynamics!Experiments: XPCSExample: capillary wave dynamics on glycerol surfaces investigated with XPCS performed at grazing anglesnormalized time correlation function22)()()()(ttt I t I t I g ττ+=described by exponential behavior1exp )(002+⎟⎟⎠⎞⎜⎜⎝⎛−=τττg g→ relaxation times τSeydel et al., Phys. Rev. B 63, 073409 (2001)The capillary wave is identified by its wave vector q and complex frequencyΓ+=i f p ωwhere the real part reflects the propagation frequency and the imaginary part the damping.At the transition from propagating to overdamped behavior f becomes purely imaginary; i.e., ωp =0.The transition from propagating (inelastic) to overdamped (quasielastic) behavior takes place at critical wave vector254ηργLV c q =with surface tension γLV , the dynamic viscosity η, and the density ρ of the polymerExample: Mixture of water and glycerol with 65% weight concentration of glycerolMadsen et al., Phys. Rev. Lett. 92, 096104 (2004)propagation frequency ωp (circles) and the dampingconstant Γ (squares) for the water -glycerol mixture at (a)30 °C and (b) 12 °C.8.8 Thin Film Preparation Techniques a) Solution-castingpreparation of thick polymer films (thickness from 100 nm to several μm)• polymer solution deposited on top of a horizontally oriented substrate• cover full substrate to have chance for uniform film if liquid is not spreading • solvent evaporates under controlled condition (T, p, atmosphere) → a solid film remains on the substrate→ allows for slow drying: films close to equilibrium can be preparedOn the scale of the capillary length the film at the substrate edges differs from the average film.Problems occur in case of pinning effects. If the contact line gets pinned during drying, no homogenous film is formed.Example: ternary blend PS, P αMS and PI cast from toluenePanagiotou, PhD Thesis TU Munich (2004)For complex fluids (highly viscous polymer solutions), the morphology is not determined by the evaporation process, the "coffee stain" effect but essentially by the capillary instabilities.Using the appropriate couple of polymer/solvent, a outward, inward or a lack of Marangoni flow in the droplets, leading to the formation of a rim, a drop or a uniform film, respectively, occurs.b) Spin-coatingpreparation of thin polymer films with thicknesses from 1 to 1000 nm• prepare polymer solution with desired concentration c • cover substrate entirely with polymer solution• select acceleration profile and spinning parameters (time, rotational speed) • start spin-coater after defined wait time → a solid film remains on the substrate→ due to non-equilibrium the film can have enrichment or lateral structuresDepending on rotational speed ω, concentration c, molecular weight Mw and apersonal parameter (wait time, person, machine)Attention: change in slope at entanglement concentration of solutionRuderer, PMB, Chem.Phys.Chem. 10, 664 (2009)Spin-coating is a complicated non-equilibrium processTheoretical description in the framework of a 3-step model (Lawrence, 1988) 1. step – start phasedeposition of solution with C 0 → strong height variationsacceleration of the substrate → most of the solution is flung-off the substrate → film thickness ≈100 μmEnd: Homogeneous film with thickness h 0 with concentration C 0 2. step – mass reduction by conventionevaporation can be neglected in comparison with the flow of solution towards to substrate edges → change of film thickness by convection2/102020341)(−⎟⎟⎠⎞⎜⎜⎝⎛+=t h h t h ηρω 3. step – evaporation of solvent through film surfaceevaporation rate of solvent larger than change in thickness by convection at a film thickness h w → mass reduction only by solvent evaporation, no polymer can leave the substrate anymore → dry, solid film remains()0,1s w f h h φ−=With the initial amount of solvent φs,0Polymer surface depends on the used solvent and on the spin-coating parameters:I: problems with solvents which have very high evaporation rate: → formation of skin on solution surface→ elastic film surface has a changed flow field of the confined polymer solution → hydrodynamic instabilities→ resulting lateral structures which have a star-shape with the center in the center of rotationII: problems with solvents which are hygroscopic and attract water from the surrounding, but are non miscible with water:→ demixing of both components (solvent and water) gives rise to lateral structuresMüller-Buschbaum et al.; Macromolecules 31, 3686 (1998)c) Floating-techniquepreparation of single and multiple polymer films (on non-wetable substrates)Schindler, Diploma Thesis TU Munich (2010)• scratch film with scalpel at 2 mm from substrate edge • put substrate into float box (tilt angle optimal at 10-15°) • add 2-3 drops of deionized water per second • remove substrate after film had decoupled• put second substrate with larger tilt angle into the water • fix polymer film on upper edge of this second substrate • remove water with 2-3 drops/sec • dry films (e.g. 4 h at 50°C)→ typically the needed time is 3-6 hours depending on the M w and film thickness→ not possible for all film thickness (thinner films are more difficult, integer number of R g can work), not possible for heat treated filmsProblems occur in case of wrinkle formation, incorporation of dust particles or trapping of water.Example: freely floating polymer film, tens of nanometers in thickness, wrinkles under the capillary force exerted by a drop of water placed on its surfaceThe wrinkling pattern is characterized by the number and length of the wrinkles.The PS film thickness h was varied from 31 to 233 nm. As the film is made thicker, the number of wrinkles N decreases (there are 111, 68, 49, and 31 wrinkles in these images).Huang et al.; Science 317, 650 (2007)d) Adsorption from solutiondeposition of single molecules, thin layers or thick films from solution with a controlled concentrationSketch:Adsorption is usually described through isotherms, that is, the amount of adsorbate on the adsorbent as a function of its pressure (if gas) or concentration (if liquid) at constant temperature.Isotherms are described bydifferent models:Langmuir isotherm (red) andBET isotherm (green)Computer simulation:Adsorption and self-assembly of linear polymers on smooth surfaces are studied using coarse-grained, bead-spring molecular models and Langevin dynamics computer simulations. The aim is to gain insight on atomic-force microscopy images of polymer films on mica surfaces, adsorbed from dilute solution following a good-solvent to bad-solvent quenching procedure.Chremos et al., Soft Matter5, 637 (2009)Molecular Weight Competition: Upon initial mixing of a formulation, all chains attempt to adsorb on a surface. For adsorbing homopolymers, thermodynamics dictates a preference for adsorption of long chains, and so short chains, originally adsorbed, are displaced form the surface at longer times.Santore+ Fu, Macromolecules 30, 8516 (1997)Fu + Santore, Macromolecules 31, 7014 (1998) Large scale industrial applications involving substantial quantities of complex fluids such as paints, inks, and coatings employ water soluble polymers with a broad distribution of molecular weights: The likelihood that some fraction of the added chains impart the desired interfacial properties means that changes in molecular weight distribution from batch to batch can dramatically impact the properties of a formulation.Experiments: Adsorption of polymers is very common in case of polyeletrolytes and used to build up multi-layers.Layer-by-Layer (LBL) assembly: fabrication of multilayers by consecutive adsorption of polyanions and polycationsDecher et al.; Science 277, 1232 (1997)Fine-tuning the film thickness by ionic strength (addition of salt yields thicker layers; polyanion from salt, polycation from pure water)Decher + Schmitt, Progr. Colloid Polym. Sci. 89, 160 (1992) A small list of polyions already used for multilayer fabrication:e) Spray coatingdeposition of thick films from solution with a controlled concentration, depending on deposition conditions (wet droplets = spraying, dry polymer = airbrush)control parameters: number of depositions, deposition time, solvent, polymer concentration, distance nozzle-surface。

Bacillus spp.

• Use:
• Modification in milk proteins • Extraction of malt infusion • Clarification of beer • Production of flavouring derived from soy • Production of animal feeds
strains well characterized – Study of gene regulation of the enzymes of
interest
Enhancing
• Enhancing of strains – increasing production to tens of g/l in processes of 50- 100 hours lasting
Commodity chemicals
• Amilases & Proteases • Bacillus:
– Good catalytic properties – High cellular density from low cost carbon and
nitrogen sources – Realise directly to the culture medium (low cost
• enzymes for human food industry (beverage,dairy products, bakery foods)
• enzymes for animal feeds
50-60% of this market are enzymes from Bacillus American, European, Japanese, Chinese companies (Novozymes, Danisco-Genencor, DSM)

形貌控制合成纳米粒子

7
(i) Rapid initial reduction leads to formation of stable nanoparticles with tetrahedral and TO shapes (ii) the reduction process is in competition with the surface capping process by the polymer (iii) the relative rates of the polymer capping, decapping and the relative reduction rates on the different surfaces determine the final shape distribution.
3
Why shape-controlling?
Tetrahedral nanoparticles are small (4.8nm), composed entirely of (111) facets with sharp edges and corners, which comprise 28% of the total atoms and 35% of the surface atoms
2
Introduce methods, synthesize nano particles with controlled shape, i.e. controlled crystal facets, for more efficient catalytic application&other applications.
Cubic(7.1nm), entirely (100),small fraction on edges and corners(~0.5%and 4%)

dielectric

Preparation and characterization of porous silica xerogelﬁlm for lowdielectric applicationJung-Kyun Hong,Hee-Sun Yang,Moon-Ho Jo,Hyung-Ho Park*,Se-Young ChoiDepartment of Ceramic Engineering,Yonsei University,134,Shinchon-dong,Seodaemoon-ku,Seoul120-749,South KoreaAbstractSiO2xerogel thinﬁlm with a low dielectric constant was successfully prepared by a two-step acid-base catalyst procedure and successive surface modiﬁcation with trimethylchlorosilane(TMCS).Only15%porosity could be obtained without surface modiﬁcation but with surface modiﬁcation the porosity increased to50%.These porosity values correspond to measured dielectric constants of3.95and2.45, respectively.The low dielectric constant was revealed to depend mainly on the porous structure of xerogel thinﬁlm obtained with surface modiﬁcation.Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses were carried out to evaluate the effect of surface modiﬁcation which induces the changes of surface coverage from–OC2H5and–OH to–CH3.Rutherford backscattering spectrometry analysis gave the porosity of SiO2xerogel thinﬁlm as47.5%.The porosity estimation using refractive index obtained from Ellipsometry work was43.2%and agrees well with RBS analysis.The network structure of SiO2xerogel was also evaluated with scanning electron microscopy and transmission electron microscopy.©1997Elsevier Science S.A.Keywords:Silica xerogelﬁlm;Low dielectric constant;Porosity characteristics1.IntroductionThe growth of integrated circuit technology is primarily based on the continued scaling down of devices to ever smaller dimensions.Smaller devices give higher packing density as well as higher operating speeds.However,with higher device speed there is an almost inevitable reduction in the interconnection delay caused by parasitic capacitance between metal layers over the basic gate delay[1].There-fore,low k(i.e.low dielectric constant)materials which substitute for conventional inter-metal dielectric(IMD) have become imperative for the reduction of parasitic capa-citance between multi-metal layers.Sol-gel derived porous SiO2thinﬁlm has great potential as an IMD,because a very low dielectric constant can be achieved from its porosity.It also has a high temperature limit and compatibility with existing microelectronics precursors[2].In particular,one of the porous SiO2gels,aerogels,has extremely high por-osity,up to95%;and its dielectric constant is close to1. With this unique characteristic,SiO2aerogel can be applied to IMD[3–5].In our previous work,we obtained SiO2 aerogel thinﬁlm with good dielectric properties as IMD by a supercritical drying procedure[6].However,this pro-cess is very energy intensive,often dangerous,and not easily adaptable to continuous thinﬁlm forming operations. Therefore,an ambient drying method for the preparation of SiO2aerogelﬁlm was studied and recently reported by Pra-kash et al.[7].This involved using dip coating of reliquiﬁed gels after surface modiﬁcation.In the present work,a novel procedure for the preparation of SiO2xerogel thinﬁlm for application to IMD is proposed. This manuscript contains the results of the fabrication and the characterization as well as the possible application to IMD of SiO2xerogel thinﬁlm.We evaluated material prop-erties by focusing on the surface modiﬁcation and the mea-surements of density and porosity which are directly related to the dielectric property.The dielectric constant of modi-ﬁed SiO2xerogel thinﬁlm was compared with that of SiO2 xerogel thinﬁlm obtained without surface modiﬁcation. 2.ExperimentalSilica sol used in this experiment was prepared using a typical two-step acid/base catalyst procedure.In theﬁrst step,tetraethylorthosilicate(TEOS),ethanol,waterandThin Solid Films308–309(1997)495–5000040-6090/97/$17.00©1997Elsevier Science S.A.All rights reservedPII S0040-6090(97)00486-0*Corresponding author.e-mail:hhpark@bubble.yonsei.ac.krHCl were mixed in the molar ratio 1:4:2:2.0×10−4at room temperature for 4h (stock solution).In the second step,0.725ml of the base-catalyst (0.5M NH 4OH)was added to 10ml of the stock solution.The gelation occurred after 30min at room temperature.The sol with viscosity between 10and 15cp was spun on p-type Si (100)wafer at 3500rev./min for 15s.Since the solvent of sol can be rapidly evapo-rated during the spin deposition,the spin coating was con-ducted in an ethanol atmosphere.The spun-on ﬁlm was aged under an ethanol atmosphere for 10min and the aged ﬁlm was immersed in n -hexane (CH 3(CH 2)4CH 3)in order to wash the ethanol in the gel network structure.After sufﬁ-cient washing,surface modiﬁcation with trimethylchlorosi-lane (TMCS,(CH 3)3SiCl)in n -hexane for 2h at 60°C and successive thermal treatment at 300°C was carried out.The experimental ﬂow is schematically illustrated in Fig.1.The coarse and ﬁne microstructures of the ﬁlms were investigated by scanning electron microscope (SEM;Hita-chi H600)and transmission electron microscope (TEM;Hitachi S2700)observations.The ﬁlm density was comple-mentarily determined using Rutherford backscattering spec-trometry (RBS;NEC6-SDH)with 2.0MeV He 2+ions and cross-sectional SEM.The composition of ﬁlm was also determined using RBS.The refractive index of SiO 2xerogel ﬁlm was measured by Ellipsometer (Gaertner Scientiﬁc;L117C)at its most shallow incident angle of 30°.The ﬁlm density was also calculated using the reported relationship with the refractive index [8]to compare with the measured density value.The chemical species and chemical bonding state were investigated using Fourier transform infrared spectroscopy (FT-IR)and X-ray photoelectron spectro-scopy (XPS).XPS analysis was performed with a V.G.Scientiﬁc ESCALAB 220i-XL spectrometer using Mg k a (1253.6eV)radiation operating at 250W.Narrow scan spectra of all regions of interest were recorded in order to quantify the surface composition and identify the elemental bonding states with pass energy of 20eV and take-off angle of 90°.The dielectric constant was directly measured using an Impedance/Gain-Phase Analyzer (Hewlett Packard;4194A)in MIS structure at 1MHz.The upper and lower electrodes were deposited with Al using a thermal evapora-tor.3.Results and discussionSiO 2xerogel thin ﬁlm was simply prepared after sur-face modiﬁcation with TMCS of spin-coated silica sol.For the preparation of aerogel/xerogel ﬁlms,a dip coating procedure is actually used [9–11].In the present work how-ever,spin coating was conducted for the insurance of good adhesion and planarization of the ﬁlm.The dielectric con-stant was measured as 2.45with MIS structure.This value is much lower than that of conventional SiO 2ﬁlm actually used in the fabrication of integrated circuits (IC).How-ever,unmodiﬁed ﬁlm shows a dielectric constant of 3.95,which is similar to that of conventional SiO 2ﬁlm.Through the surface modiﬁcation,SiO 2xerogel ﬁlm has a unique porous structure,and it shows a very low dielectric con-stant.Table 1summarizes the density,porosity,refractive index and calculated and measured dielectric constants of unmodiﬁed and modiﬁed ﬁlms.The ﬁlm density,r ,can be determined from the measured refractive index (n ),using the relationship,r =(n −1)/0.202for silica xerogel.The dielectric constant (k)and the porosity (P )of the ﬁlms were calculated indirectly from the density.The ﬁlm por-osity was obtained from the relationship,P =1−r /r s where r s (thermally grown conventional SiO 2ﬁlm)=2.27g/cm 3and similarly;the dielectric constant of SiO 2xerogel ﬁlm was determined from the relationship k =1+1.28r ,so k =1+6.33(n −1)[8].The density of unmodiﬁed SiO2Fig.1.Experimental ﬂow of sample preparation.496J.-K.Hong et al./Thin Solid Films 308–309(1997)495–500xerogel ﬁlm (1.93g/cm 3)calculated from the refractive index was not much smaller than that of conventional SiO 2ﬁlm (2.27g/cm 3).However,the density of modiﬁedSiO 2xerogel ﬁlm (1.29g/cm 3)was half the density of con-ventional SiO 2ﬁlm.These density values correspond to the dielectric constants of 2.65and 3.47,respectively.These values are somewhat different from directly measured values (2.45and 3.95),but refractive index can be used for roughly anticipating the physical properties of SiO 2xer-ogel ﬁlm.In some sol-gel derived ﬁlms prepared by dip coating,the porosity of the ﬁlm could be controlled in the approximate range 10–50%without surface modiﬁcation [9–11].In this work however,silica sol was so rapidly spun-on that only a few %of porosity could be achieved without surface modiﬁcation.However,in the surface mod-iﬁed xerogel with TMCS,drying shrinkage is reversible because the hydroxylated surface of SiO 2gel is changed with organosilanes (–Si(CH 3)3)[12].Organosilyl-termi-nated surfaces do not participate in condensation reaction or hydrogen bonding as the gel is collapsed by the capillary tension developed during drying,therefore the shrunkenTable 1Characteristic data of SiO 2xerogelModiﬁed ﬁlmUnmodiﬁed ﬁlm Ellipsometer Density (g/cm 3) 1.29 1.93Refractive index 1.26 1.39Porosity (%)43.215.0Dielectric constant (calculated) 2.65 3.47RBS/SEMDensity (g/cm 3) 1.19 2.17Porosity (%)47.5 4.5Dielectric constant (calculated) 2.52 3.78MIS structureDielectric constant (measured)2.453.95Fig.2.SEM micrographs of SiO 2xerogel ﬁlms;(a)modiﬁed and (b)unmodiﬁed ﬁlms.497J.-K.Hong et al./Thin Solid Films 308–309(1997)495–500elastic network progressively springs back toward its origi-nal porous state [13].The surface morphology and thickness of SiO 2xerogel ﬁlm are clearly shown in SEM micrographs in paring with unmodiﬁed ﬁlm in Fig.2b,the surface morphology of modiﬁed ﬁlm is more porous than that of unmodiﬁed ﬁlm.Unmodiﬁed ﬁlm consists of very small size particles (Ͻ10nm)and appears to form dense SiO 2ﬁlm,but modiﬁed ﬁlm appears to consist of coarse (~40nm)particles and pores.Modiﬁed SiO 2xerogel ﬁlms showed good thickness uniformity,and the average ﬁlm thickness was measured as 550nm.This value is larger than that of unmodiﬁed ﬁlm (420nm)coated under the same conditions.The aging effect in n -hexane during the washing and surface modiﬁcation step induces the particle growth.The formation of nm-scale pores is due to the rever-sible shrinkage which can be achieved through the replace-ment of hydroxylated surface with TMCS [12].To obtain detailed information on network structure,SiO 2xerogel ﬁlm dispersed in ethanol was observed using TEM.The particles shown in Fig.3have sizes between 30and 40nm and build up a 3-dimensional network in SiO 2xerogel ﬁlm.This result is in agreement with the SEM observation.RBS analysis was conducted to determine the porosity of SiO 2xerogel ﬁlm.The density of ﬁlm,which is the most crucial ﬁlm property for low dielectric application,can be determined by integrating the peak area of each elemental range in the RBS spectrum and considering the ﬁlm thick-ness measured using cross-sectional SEM observation.Theporosity of ﬁlm can be directly calculated from density.The RBS spectrum of modiﬁed xerogel ﬁlm is given in Fig.4.In the present work,the density of modiﬁed SiO 2xerogel ﬁlm was determined as l.19g/cm 3.In the case of unmodiﬁed ﬁlm,the ﬁlm density was 2.17g/cm 3.The porosity was calculated under the assumption that the silica framework density is that of thermally grown SiO 2ﬁlm (2.27g/cm 3).The corresponding porosity values were 47.5%and 4.5%for modiﬁed and unmodiﬁed ﬁlms,respectively.With RBS analyses obtained from modiﬁed and unmodi-ﬁed ﬁlms,the composition of ﬁlm,i.e.ratios of O/Si and C/Si,could also be deduced by measuring the yield height of each element.The atomic ratios of Si:O:C were calculated to be 1.0:2.35:0.95and 1.0:2.14:1.21for each sample.In the unmodiﬁed xerogel ﬁlm,O to Si ratio (2.35)is relatively higher than that of conventional SiO 2due to the ethoxy group (–OC 2H 5).In the modiﬁed ﬁlm;the O to Si ratio somewhat decreased but the C to Si ratio increased in com-parison with the unmodiﬁed ﬁlm.From these,it could be deduced that the surface hydroxyl group was replaced by a methyl silyl group during the surface modiﬁcation with TMCS.FT-IR analysis was conducted to obtain information about surface bonding characteristics and evidence of sur-face modiﬁcation.The spectra of as-received unmodiﬁed,thermally treated (at 300°C)unmodiﬁed and modiﬁed ﬁlms are given in Fig.5.In the as-received unmodiﬁed ﬁlm,besides a skeletal Si–O–Si peak,two kinds of C–H stretch-ing peaks and a broad O–H vibration peak centered at 3400cm −1were observed.The peak at 2885cm −1is due to the–Fig.3.TEM micrograph of modiﬁed SiO 2xerogelﬁlm.Fig.4.RBS spectrum of modiﬁed SiO 2xerogel ﬁlm with 2MeV He 2+.498J.-K.Hong et al./Thin Solid Films 308–309(1997)495–500CH 2–of the ethoxy group;and the peak at 2975cm −1is due to the –CH 3of the ethoxy group.This means that the xer-ogel ﬁlm has a lot of ethoxy groups caused by incomplete hydrolysis of TEOS or re-esteriﬁcation [14].These C–H stretching peaks disappeared in thermally treated unmodi-ﬁed ﬁlm at 300°C due to thermal volatility of the ethoxy group.However,the C–H stretching peak due to –CH 3in modiﬁed ﬁlm still appeared at 2965cm −1[7].This means that they have a different chemical environment to each other.The surface of unmodiﬁed xerogel ﬁlm is covered with –OC 2H 5;on the contrary TMCS-modiﬁed xerogel ﬁlm is covered with –CH 3.The C–H stretching peak from TMCS is also found in modiﬁed SiO 2xerogel ﬁlm at 880cm −1due to the Si–C stretching peak vibration [15].The broad O–H peak centered at 3400cm −1is clearly reduced in the modiﬁed ﬁlm due to the replacement of surface hydroxylgroup with methyl silyl group.This result is veriﬁed by RBS analysis.The peak corresponding to absorbed water was observed in as-received unmodiﬁed ﬁlm,but after thermal treatment,the absorbed water was almost removed.In the application of SiO 2xerogel ﬁlm to IMD,the absorbed moisture is very important because it can potentially cause the corrosion of the underlying metal line and also degrade ﬁlm adhesion.In modiﬁed ﬁlm,the absorbed water was also almost removed.A more detailed composition and chemical bonding state of the SiO 2xerogel ﬁlm surface was also examined using XPS.The surface compositions of the above three kinds of SiO 2xerogel ﬁlms are given in Fig.6.The XPS analysis shows that the surface of SiO 2xerogel ﬁlm consists mainly of silicon,oxygen and carbon.The carbon peak is essen-tially composed of C–C/H and C–O bonds,and the silicon peak is mainly composed of Si–O–Si,Si–O–C,Si–O–H and Si–C bonds.The O to Si ratio,3.1,is also much higher than the stoichiometric ratio,2.0.This means that some oxygen has additional bonding states as Si–O–C and Si–O–H bonds.Through the thermal treatment,the surface Si–O–C group was oxidized and changed to Si–O–H.The concentration of carbon is then remarkably reduced but the O to Si ratio is little changed in thermally treated unmo-diﬁed ﬁlm.This result is veriﬁed with the disappearance of the C–H stretching peak and the appearance of the SiO–H peak (3750cm −1)in FT-IR analysis.From the XPS narrow scan analyses in particular,the C 1s spectrum presents the most remarkable change in peak shape of each sample and they are shown in Fig.7.The peak binding energies of 284.7eV,286.4eV and 283.5eV correspond to C–C/H,C–OandFig.5.FT-IR spectra of SiO 2xerogel ﬁlms;(a)as-received unmodiﬁed,(b)thermally-treated unmodiﬁed (300°C),and (c)modiﬁedﬁlms.Fig.6.Atomic compositions of SiO 2xerogel ﬁlms by XPS;(a)as-received unmodiﬁed,(b)thermally treated unmodiﬁed (300°C),and (c)modiﬁed ﬁlms.499J.-K.Hong et al./Thin Solid Films 308–309(1997)495–500C–Si bonds,respectively [16].The decrease of the C–O bond in thermally treated ﬁlm and the appearance of the C–Si bond in modiﬁed ﬁlm with TMCS is clearly seen.These XPS analyses verify that the surface of SiO 2xerogel is modiﬁed with TMCS.4.ConclusionsSurface modiﬁed SiO 2xerogel ﬁlm after spin coating was dried in air and thermally treated at 300°C.It showed about 50%of porosity and a dielectric constant lower than 2.5.On the contrary,only a small percentage of porosity could beachieved with unmodiﬁed sol-gel derived SiO 2ﬁlm.The surface modiﬁcation prevents gel network collapse during the drying process.As a result,the modiﬁed ﬁlm has high porosity and a low dielectric constant.With MIS structure,a dielectric constant of 2.45was directly measured.The dielectric constant of modiﬁed ﬁlm could also be obtained from the refractive index by Ellipsometry and the density by RBS analysis.They were 2.65and 2.52,respectively.These values are much lower than that of conventional SiO 2ﬁlm.The 3-dimensional network of particulate (30–40nm)con-structing porous SiO 2xerogel ﬁlm was clearly observed by TEM work.The surface coverages of modiﬁed and unmo-diﬁed ﬁlms are revealed to be different due to the successful modiﬁcation with TMCS.The spectroscopic work shows that the surface of the modiﬁed ﬁlm was covered with –CH 3,but on the other hand,the surface of the unmodiﬁed ﬁlm was covered with mainly –OC 2H 5and –OH.AcknowledgementsThis work was supported by the Ministry of Education through the Inter-University Semiconductor Research Cen-ter (ISRC 96-E-1063)in Seoul National University.References[1]C.B.Case, A.Kornblit,u and N.H.Hendricks,Proc.ISMIC Conf.,104(1995)116.[2]D.M.Smith,J.Anderson,C.C.Cho,G.P.Johnston and S.P.Jeng,Proc.Mat.Res.Symp.,381(1995)261.[3]L.W.Hrubesh and J.F.Poco,J.Non-Cryst.Solids,188(1995)46.[4]L.W.Hrubesh,L.E.Keene and torre,J.Mater.Res.,8(1993)1736.[5]P.Bru ¨esch,F.Stucki,Th.Baumann,P.Kluge-Weiss,B.Bru ¨hl,L.Niemeyer,R.Stru ¨mpler,B.Ziegier and M.Mielke,Appl.Phys.A.,57(1993)329.[6]M.H.Jo,J.K.Hong,H.H.Park,J.J.Kim and S.H.Hyun,Microelec-tronic Engineering,33(1997)343.[7]S.S.Prakash,C.J.Brinker and A.J.Hurd,J.Non-Cryst.Solids,190(1995)264.[8]S.Henning and L.Svenson,Phys.Scripta,23(1981)697.[9]C.J.Brinker,A.J.Hurd and K.J.Ward,in J.D.Mackanzie and D.R.Ulrich (eds.),Ultrastructure Processing of Advanced Ceramics ,Wiley,New York,1988,p.223.[10]H.Schmidt,G.Rinn,R.Nass and D.Sporn,in C.J.Brinker,D.E.Clark and D.R.Ulich (eds.),Better Ceramics Through Chemistry III ,Material Research Society,Pittsburg,PA,1988,p.743.[11]H.Hirashima and K.Sudoh,J.Non-Cryst.Solids,145(1992)51.[12]S.S.Prakash,C.J.Brinker,A.J.Hurd and S.M.Rao,Nature,374(1995)439.[13]E.P.Plueddemann,Silane Coupling Agents ,Plenum,New York,1991.[14]C.J.Brinker and G.W.Scherer,Sol-Gel Science ,Academic Press,San Diego,1990,Ch.9,p.581.[15]U.Mackens and U.Merkt,Thin Solid Films,97(1982)53.[16]H.H.Park,K.H.Kwon,J.L.Lee,et al.,J.Appl.Phys.76(1994)4596.Fig.7.Changes of C 1s spectra in SiO 2xerogel ﬁlms;(a)as-received unmodiﬁed,(b)thermally treated unmodiﬁed (300°C),and (c)modiﬁed ﬁlms.500J.-K.Hong et al./Thin Solid Films 308–309(1997)495–500。

Haptic and Tactile Displays

Haptic and Tactile DisplaysGeb ThomasUniversity of IowaHaptic versus Tactile (my owndistinction)•Dictionaries usually list these as synonyms •Haptic devices interact with the muscles and position of the hand and finger joints. This may include pressure sensation, but it typically involved in the global posture and integration of the sensation across different portions of the hand.•Tactile devices interact with the fingertips and the shape and position sensors under the fingertips (and more generally, the skin).Well-Known Haptic Devices Up to 22 high-accuracy joint-angle measurements. It usesproprietary resistive bend-sensing technology to accurately transform hand and finger motions into real-time digital joint-angle data./CybergraspForce feedbacksystem allowsuser to interactwith virtualobjects withprogrammingthat correlatesobject and jointposition.P5 (relatively new)Designed for games.Comes with gesturerecognition and virtualkeyboard.Phantom DesktopBy sensable technologies(MIT spin-off)Moves like a 3D cursor3 DOF force feedbackPassive twist, pitch and rollangles.Supped up Phantom6 DOFGreater force controlWhat are they good for?•Molecular docking simulations•Nice 3D input device•Interaction with virtual reality•Robot control•Games•Virtual sculpting•Medical simulationWhat are the key designfactors for the gloves?•Glove absolute position is bad, relative isgood.•Wearing the glove is tiring and hard on theglove.•Gesture recognition is harder than you think(but packages help)•To make a hand look right in VR you need toknow the user’s hand geometry•Usually you need a separate system for theposition of the hand relative to 3D spaceWhat are the key designfactors for the Phantom •Interactions with hard surfaces can cause nasty vibrations (inherent instability in the math).•Very convenient for long use•High precision, but control loop requires higher precision than you can use (time and space)•Rubbery, smooth and slippery-sticky objects are easy to model. Fluids and skin are more difficult.Another force feedback deviceMagnetic levitationDeveloped at CMU byMicrodynamics systems labTactileUses•Aids for the blind•Could provide detailed shape and texture information in virtual environments•Largely unexplored, compared to vision, for example.•Gaining information through touching is strangely unpopular in our culture --too intense a sensationYour 2m2of skin•90% hairy, 10% glabrous (hairless)•Accessible•Richly innervated•Precise discrimination•Adaptable to spatial and temporal displays•Present and potential applications •Mechanisms of normal touch perception •Technology for producing tactile displays •Practical considerationsTraditional displays for theblind•Braille (6-dot matrix, 2.3mm separation, 125 words*min-1)•Sign language: finger spelling: 6 letters* sec-1, American Sign Language: 4-5 syllables*sec-1)•Tadoma 3 syllables*sec-1Tactile Feedback from tactilesensors•For people with poor haptic perception in their hands (Hansen’s disease, suited astronauts)•strain gauges on a glove to foreheadelectrodes: can detect shape and texture!•Movable pins, enhanced fingerpads, tactilepads, glove-hand adhesion, removable glove fingertip•Sample task: no feedback: 92s, forcefeedback 63s, barehanded: 14sTactile auditory substitution •Auditory prosthesis which adjusts the perceived intensity of 16 electrodes, each corresponding to the sound intensity of a given passband in the audio spectrum.•Improve speech clarity for deaf children •Improve auditory discrimination and comprehension in older patientsTactile vision substitution(TVS)•Television Camera to users skin with a vibrotactile or electrotactile stimulators array.•Stimulation intensity is controlled by grayscale•Distal attribution --with practice, user perceives the stimulation to be in front of themTactile Reading•Optacon 6x24-row vibrating fingerpad •90 words*min-1exceptional 28words*min-1normal•Now discontinued•Significant underground calling for its resurgenceStatic tactile displays•64-solenoid, four level displaypresenting graphical information •Another model has one prime mover and many piezoelectric latches •Muscle wire displayVirtual tactile tablet •Fingerpad vibrotactile stimulation arrayon a mouse•5x20 array of pin vibrotactors mounted directly above t-shaped mouse •Minsky’s sandpaper displayHuman Tactile Perception •Six types of cutaneous receptors, four functions•Fast adapting, broad receptive field (FAII) --high-frequency vibration•Fast adapting, small receptive field (FAI) --localized movement fine form and texture•Slow adapting, large-field (SAII) --maybe notinvolved in haptics•Slow adapting, small-field (SAI) --form androughnessMeasures•Smallest amount of pressure•Two-point limen (two point discrimination threshold TPDT)•Affected by location, practice, fatigue, distraction•Modeling attempts include convolving integral, low-pass filter or Gaussian blurDesign Criteria•Static tactile displays•Vibrotactile displays•Electrotactile displaysStatic•High power consumption•Rapid adaptation to static stimuli•12-20mm height to match Optacon accuracyVibrotactile •Threshold: 5 micro-m at 25-650 Hz for small areas (<.05 cm2)•Adaptation to strong stimuli•Full recovery requires 2 min.•160 Hz is best•10dB over threshold•1 mm diameter stimulator with .5mmmovementElectrotactile Displays •Current through skin•Current-limited•Balanced, biphasic pulses with zero net DC current•Electrodes to produce appropriate ions (gold, platinum, silver)•Electrode size is important•Some are implantableImportant Issues•Pain threshold•Skin condition•Sensory adaptation•Subjective magnitude of electrotactile stimulationWhat does this mean to you?•A large class of novel displays•A largely untapped domain of HCI•A lot of the brain is devoted to touch, but we know very little about this •Potential to increase realism of VR •Potential to help vision-impared people •Potential to create emotionally stirring interfacesReferences•Adams, R.J.; Hannaford, B., "Stable haptic interaction with virtual environments," Robotics and Automation, IEEE Transactions on , vol.15, no.3, pp.465-474, Jun 1999•Burdea, G.C. "Virtual Reality and Medicine: Technology and Applications", Rutgers Dept. of Electrical and Computer Engineering, 1997•Kaczmarek, K.A. and Bach-Y-Rita, P. (1995), Tactile displays, in Virtual Environments and Advanced Interface Design, Barfield and Furness,•。

Principles of Plasma Discharges and Materials Processing第1章

CHAPTER 1INTRODUCTION1.1MATERIALS PROCESSINGChemically reactive plasma discharges are widely used to modify the surface prop-erties of materials.Plasma processing technology is vitally important to several of the largest manufacturing industries in the world.Plasma-based surface processes are indispensable for manufacturing the very large scale integrated circuits (ICs)used by the electronics industry.Such processes are also critical for the aerospace,automotive,steel,biomedical,and toxic waste management industries.Materials and surface structures can be fabricated that are not attainable by any other commer-cial method,and the surface properties of materials can be modiﬁed in unique ways.For example,0.2-m m-wide,4-m m-deep trenches can be etched into silicon ﬁlms or substrates (Fig.1.1).A human hair is 50–100m m in diameter,so hundreds of these trenches would ﬁt endwise within a human hair.Unique materials such as diamond ﬁlms and amorphous silicon for solar cells have also been produced,and plasma-based hardening of surgically implanted hip joints and machine tools have extended their working lifetimes manyfold.It is instructive to look closer at integrated circuit fabrication,which is the key application that we describe in this book.As a very incomplete list of plasma pro-cesses,argon or oxygen discharges are used to sputter-deposit aluminum,tungsten,or high-temperature superconducting ﬁlms;oxygen discharges can be used to grow SiO 2ﬁlms on silicon;SiH 2Cl 2=NH 3and Si(OC 2H 5)4=O 2discharges are used for the plasma-enhanced chemical vapor deposition (PECVD)of Si 3N 4and SiO 2ﬁlms,1Principles of Plasma Discharges and Materials Processing ,by M.A.Lieberman and A.J.Lichtenberg.ISBN 0-471-72001-1Copyright #2005John Wiley &Sons,Inc.respectively;BF 3discharges can be used to implant dopant (B)atoms into silicon;CF 4=Cl 2=O 2discharges are used to selectively remove silicon ﬁlms;and oxygen dis-charges are used to remove photoresist or polymer ﬁlms.These types of steps (deposit or grow,dope or modify,etch or remove)are repeated again and again in the manufacture of a modern IC.They are the equivalent,on a micrometer-size scale,of centimeter-size manufacture using metal and components,bolts and solder,and drill press and lathe.For microfabrication of an IC,one-third of the tens to hundreds of fabrication steps are typically plasma based.Figure 1.2shows a typical set of steps to create a metal ﬁlm patterned with sub-micrometer features on a large area (300mm diameter)wafer substrate.In (a ),the ﬁlm is deposited;in (b ),a photoresist layer is deposited over the ﬁlm;in (c ),the resist is selectively exposed to light through a pattern;and in (d ),the resist is developed,removing the exposed resist regions and leaving behind a patterned resist mask.In (e ),this pattern is transferred into the ﬁlm by an etch process;the mask protects the underlying ﬁlm from being etched.In (f ),the remaining resist mask is removed.Of these six steps,plasma processing is generally used for ﬁlm deposition (a )and etch (e ),and may also be used for resist development (d )and removal (f ).The etch process in (e )is illustrated as leading to vertical sidewalls aligned with the resist mask;that is,the mask pattern has been faithfully transferred into the metal ﬁlm.This can be accomplished by an etch process that removes material in the vertical direction only.The horizontal etch rate is zero.Such anisotropic etches are easily produced by plasma processing.On the other hand,one mightimagineFIGURE 1.1.Trench etch (0.2m m wide by 4m m deep)in single-crystal silicon,showing the extraordinary capabilities of plasma processing;such trenches are used for device isolation and charge storage capacitors in integrated circuits.2INTRODUCTIONthat exposing the masked ﬁlm (d )to a liquid (or vapor phase)etchant will lead to the undercut isotropic proﬁle shown in Figure 1.3a (compare to Fig.1.2e ),which is produced by equal vertical and horizontal etch rates.Many years ago,feature spa-cings (e.g.,between trenches)were tens of micrometers,much exceeding required ﬁlm thicknesses.Undercutting was then acceptable.This is no longer true with submicrometer feature spacings.The reduction in feature sizes and spacings makes anisotropic etch processes essential.In fact,strictly vertical etches are some-times not desired;one wants controlled sidewall angles.Plasma processing is the only commercial technology capable of such control.Anisotropy is a critical process parameter in IC manufacture and has been a major force in driving the development of plasma processing technology.The etch process applied to remove the ﬁlm in Figure 1.2d is shown in Figure 1.2e as not removing,either the photoresist or the underlying substrate.This selectivity is another critical process parameter for IC manufacture.Whereas FIGURE 1.2.Deposition and pattern transfer in manufacturing an integrated circuit:(a )metal deposition;(b )photoresist deposition;(c )optical exposure through a pattern;(d )photoresist development;(e )anisotropic plasma etch;(f )remaining photoresist removal.1.1MATERIALS PROCESSING 3wet etches have been developed having essentially inﬁnite selectivity,highly selec-tive plasma etch processes are not easily designed.Selectivity and anisotropy often compete in the design of a plasma etch process,with results as shown in Figure 1.3b .Compare this to the idealized result shown in Figure 1.2e .Assuming that ﬁlm-to-substrate selectivity is a critical issue,one might imagine simply turning off the plasma after the ﬁlm has been etched through.This requires a good endpoint detection system.Even then,variations in ﬁlm thickness and etch rate across the area of the wafer imply that the etch cannot be stopped at the right moment every-where.Hence,depending on the process uniformity ,there is a need for some selectivity.These issues are considered further in Chapter 15.Here is a simple recipe for etching silicon using a plasma discharge.Start with an inert molecular gas,such as CF 4.Excite the discharge to sustain a plasma by electron–neutral dissociative ionization,e þCF 4À!2e þCF þ3þFand to create reactive species by electron–neutral dissociation,e þCF 4À!e þF þCF 3À!e þ2F þCF2FIGURE 1.3.Plasma etching in integrated circuit manufacture:(a )example of isotropic etch;(b )sidewall etching of the resist mask leads to a loss of anisotropy in ﬁlm etch;(c )illustrating the role of bombarding ions in anisotropic etch;(d )illustrating the role of sidewall passivating ﬁlms in anisotropic etch.4INTRODUCTIONThe etchant F atoms react with the silicon substrate,yielding the volatile etch product SiF4:Si(s)þ4F(g)À!SiF4(g)Here,s and g indicate solid and gaseous forms,respectively.Finally,the product is pumped away.It is important that CF4does not react with silicon,and that the etch product SiF4is volatile,so that it can be removed.This process etches siliconisotropically.For an anisotropic etch,there must be high-energy ion(CFþ3)bombard-ment of the substrate.As illustrated in Figures1.3c and d,energetic ions leaving the discharge during the etch bombard the bottom of the trench but do not bombard the sidewalls,leading to anisotropic etching by one of two mechanisms.Either the ion bombardment increases the reaction rate at the surface(Fig.1.3c),or it exposes the surface to the etchant by removing passivatingﬁlms that cover the surface(Fig.1.3d).Similarly,Cl and Br atoms created by dissociation in a discharge are good etch-ants for silicon,F atoms and CF2molecules for SiO2,O atoms for photoresist,and Cl atoms for aluminum.In all cases,a volatile etch product is formed.However,F atoms do not etch aluminum,and there is no known etchant for copper,because the etch products are not volatile at reasonable substrate temperatures.We see the importance of the basic physics and chemistry topics treated in this book:(1)plasma physics(Chapters2,4–6,and18),to determine the electron and ion densities,temperatures,and ion bombardment energies andﬂuxes for a given dis-charge conﬁguration;and(2)gas-phase chemistry and(3)surface physics and chem-istry(Chapters7and9),to determine the etchant densities andﬂuxes and the etch rates with and without ion bombardment.The data base for theseﬁelds of science is provided by(4)atomic and molecular physics,which we discuss in Chapters3 and8.We also discuss applications of equilibrium thermodynamics(Chapter7)to plasma processing.The measurement and experimental control of plasma and chemical properties in reactive discharges is itself a vast subject.We provide brief introductions to some simple plasma diagnostic techniques throughout the text.We have motivated the study of the fundamentals of plasma processing by exam-ining isotropic and anisotropic etches for IC manufacture.These are discussed in Chapter15.Other characteristics motivate its use for deposition and surface modi-ﬁcation.For example,a central feature of the low-pressure processing discharges that we consider in this book is that the plasma itself,as well as the plasma–substrate system,is not in thermal equilibrium.This enables substrate temperatures to be relatively low,compared to those required in conventional thermal processes, while maintaining adequate deposition or etch rates.Putting it another way,plasma processing rates are greatly enhanced over thermal processing rates at the same sub-strate temperature.For example,Si3N4ﬁlms can be deposited over aluminumﬁlms by PECVD,whereas adequate deposition rates cannot be achieved by conventional chemical vapor deposition(CVD)without melting the aluminumﬁlm.Chapter16 gives further details.Particulates or“dust”can be a signiﬁcant component in processing discharges and can be a source of substrate-level contamination in etch and deposition1.1MATERIALS PROCESSING56INTRODUCTIONprocesses.One can also control dust formation in useful ways,for example,to produce powders of various sizes or to incorporate nanoparticles during deposition to modifyﬁlm properties.Dusty plasmas are described in Chapter17.The nonequilibrium nature of plasma processing has been known for many years, as illustrated by the laboratory data in Figure1.4.In time sequence,this showsﬁrst, the equilibrium chemical etch rate of silicon in the XeF2etchant gas;next,the tenfold increase in etch rate with the addition of argon ion bombardment of the sub-strate,simulating plasma-assisted etching;andﬁnally,the very low“etch rate”due to the physical sputtering of silicon by the ion bombardment alone.A more recent application is the use of plasma-immersion ion implantation(PIII)to implant ions into materials at dose rates that are tens to hundreds of times larger than those achievable with conventional(beam based)ion implantation systems.In PIII,a series of negative high-voltage pulses are applied to a substrate that is immersed directly into a discharge,thus accelerating plasma ions into the substrate.The devel-opment of PIII has opened a new implantation regime characterized by very high dose rates,even at very low energies,and by the capability to implant both large area and irregularly shaped substrates,such asﬂat panel displays or machine tools and dies. This is illustrated in Figure1.5.Further details are given in Chapter16.1.2PLASMAS AND SHEATHSPlasmasA plasma is a collection of free charged particles moving in random directions that is,on the average,electrically neutral(see Fig.1.6a).This book deals withweakly Array FIGURE1.4.Experimental demonstration of ion-enhanced plasma etching.(Coburn and Winters,1979.)ionized plasma discharges,which are plasmas having the following features:(1)they are driven electrically;(2)charged particle collisions with neutral gas mol-ecules are important;(3)there are boundaries at which surface losses are important;(4)ionization of neutrals sustains the plasma in the steady state;and (5)the electrons are not in thermal equilibrium with the ions.A simple discharge is shown schematically in Figure 1.6b .It consists of a voltage source that drives current through a low-pressure gas between two parallel conduct-ing plates or electrodes.The gas “breaks down”to form a plasma,usually weakly ionized,that is,the plasma density is only a small fraction of the neutral gas density.We describe some qualitative features of plasmas in this section;discharges are described in the following section.Plasmas are often called a fourth state of matter.As we know,a solid substance in thermal equilibrium generally passes into a liquid state as the temperature is increased at a ﬁxed pressure.The liquid passes into a gas as the temperature is further increased.At a sufﬁciently high temperature,the molecules in the gas decompose to form a gas of atoms that move freely in random directions,except for infrequent collisions between atoms.If the temperature is furtherincreased,FIGURE 1.5.Illustrating ion implantation of an irregular object:(a )In a conventional ion beam implanter,the beam is electrically scanned and the target object is mechanically rotated and tilted to achieve uniform implantation;(b )in plasma-immersion ion implantation (PIII),the target is immersed in a plasma,and ions from the plasma are implanted with a relatively uniform spatialdistribution.VFIGURE 1.6.Schematic view of (a )a plasma and (b )a discharge.1.2PLASMAS AND SHEATHS 7then the atoms decompose into freely moving charged particles(electrons and positive ions),and the substance enters the plasma state.This state is characterized by a common charged particle density n e%n i%n particles/m3and,in equilibrium, a temperature T e¼T i¼T.The temperatures required to form plasmas from puresubstances in thermal equilibrium range from roughly4000K for easy-to-ionize elements like cesium to20,000K for hard-to-ionize elements like helium.The fractional ionization of a plasma isx iz¼n i n gþn iwhere n g is the neutral gas density.x iz is near unity for fully ionized plasmas,and x iz(1for weakly ionized plasmas.Much of the matter in the universe is in the plasma state.This is true because stars,as well as most interstellar matter,are plasmas.Although stars are plasmas in thermal equilibrium,the light and heavy charged particles in low-pressure proces-sing discharges are almost never in thermal equilibrium,either between themselves or with their surroundings.Because these discharges are electrically driven and are weakly ionized,the applied power preferentially heats the mobile electrons,while the heavy ions efﬁciently exchange energy by collisions with the background gas. Hence,T e)T i for these plasmas.Figure1.7identiﬁes different kinds of plasmas on a log n versus log T e diagram. There is an enormous range of densities and temperatures for both laboratory and space plasmas.Two important types of processing discharges are indicated on the ﬁgure.Low-pressure discharges are characterized by T e%1–10V,T i(T e,and n%108–1013cm23.These discharges are used as miniature chemical factories in which feedstock gases are broken into positive ions and chemically reactive etch-ants,deposition precursors,and so on,which thenﬂow to and physically or chemi-cally react at the substrate surface.While energy is delivered to the substrate also, for example,in the form of bombarding ions,the energyﬂux is there to promote the chemistry at the substrate,and not to heat the substrate.The gas pressures for these discharges are low:p%1mTorr–1Torr.These discharges and their use for processing are the principal subject of this book.We give the quantitative frame-work for their analysis in Chapter10.High-pressure arc discharges are also used for processing.These discharges have T e%0.1–2V and n%1014–1019cm23,and the light and heavy particles are more nearly in thermal equilibrium,with T i.T e.These discharges are used mainly to deliver heat to the substrate,for example,to increase surface reaction rates, to melt,sinter,or evaporate materials,or to weld or cut refractory materials.Opera-ting pressures are typically near atmospheric pressure(760Torr).High-pressure discharges of this type are beyond the scope of this book.Figure1.8shows the densities and temperatures(or average energies)for various species in a typical rf-driven capacitively coupled low-pressure discharge;for example,for silicon etching using CF4,as described in Section1.1.We see that the feedstock gas,etchant atoms,etch product gas,and plasma ions have roughly 8INTRODUCTIONthe same temperature,which does not exceed a few times room temperature (0.026V).The etchant F and product SiF 4densities are signiﬁcant fractions of the CF 4density,but the fractional ionization is very low:n i 10À5n g .The electron temperature T e is two orders of magnitude larger than the ion temperature T i .However,we note that the energy of ions bombarding the substrate can be 100–1000V,much exceeding T e .The acceleration of low-temperature ions510152025log 10 T (V)el o g 10n (c m –3)FIGURE 1.7.Space and laboratory plasmas on a log n versus log T e diagram (after Book,1987).l De is deﬁned in Section 2.4.1.2PLASMAS AND SHEATHS 9across a thin sheath region where the plasma and substrate meet is central to all pro-cessing discharges.We describe this qualitatively below and quantitatively in later chapters.Although n i and n e may be ﬁve orders of magnitude lower that n g ,the charged particles play central roles in sustaining the discharge and in processing.Because T e )T i ,it is the electrons that dissociate the feedstock gas to create the free radicals,etchant atoms,and deposition precursors,required for the chemistry at the substrate.Electrons also ionize the gas to create the positive ions that sub-sequently bombard the substrate.As we have seen,energetic ion bombardment can increase chemical reaction rates at the surface,clear inhibitor ﬁlms from the surface,and physically sputter materials from or implant ions into the surface.T e is generally less than the threshold energies E diss or E iz for dissociation and ionization of the feedstock gas molecules.Nevertheless,dissociation and ionization occur because electrons have a distribution of energies.Letting g e (E )d E be the number of electrons per unit volume with energies lying between E and E þd E ,then the distribution function g e (E )is sketched in Figure 1.9.Electrons having ener-gies below E diss or E iz cannot dissociate or ionize the gas.We see that dissociation and ionization are produced by the high-energy tail of the distribution.Although the distribution is sketched in the ﬁgure as if it were Maxwellian at the bulk electron temperature T e ,this may not be the case.The tail distribution might be depressed below or enhanced above a Maxwellian by electron heating and electron–neutral collision processes.Two temperature distributions are sometimes observed,with Te 1081010n (c m –3)T or ·Ò (V)FIGURE 1.8.Densities and energies for various species in a low-pressure capacitive rf discharge.10INTRODUCTIONfor the bulk electrons lower than T h for the energetic electron tail.Non-Maxwellian distributions can only be described using the kinetic theory of discharges,which we introduce in Chapter 18.SheathsPlasmas,which are quasi-neutral (n i %n e ),are joined to wall surfaces across thin positively charged layers called sheaths .To see why,ﬁrst note that the electron thermal velocity (e T e =m )1=2is at least 100times the ion thermal velocity (e T i =M )1=2because m =M (1and T e &T i .(Here,T e and T i are given in units of volts.)Consider a plasma of width l with n e ¼n i initially conﬁned between two grounded (F ¼0)absorbing walls (Fig.1.10a ).Because the net charge density r ¼e (n i Àn e )is zero,the electric potential F and the electric ﬁeld E x is zero every-where.Hence,the fast-moving electrons are not conﬁned and will rapidly be lost to the walls.On a very short timescale,however,some electrons near the walls are lost,leading to the situation shown in Figure 1.10b .Thin (s (l )positive ion sheaths form near each wall in which n i )n e .The net positive r within the sheaths leads to a potential proﬁle F (x )that is positive within the plasma and falls sharply to zero near both walls.This acts as a conﬁning potential “valley”for electrons and a “hill”for ions because the electric ﬁelds within the sheaths point from the plasma to the wall.Thus the force ÀeE x acting on electrons is directed into the plasma;this reﬂects electrons traveling toward the walls back into the plasma.Conversely,ions from the plasma that enter the sheaths are accel-erated into the walls.If the plasma potential (with respect to the walls)is V p ,then we expect that V p a few T e in order to conﬁne most of the electrons.The energy of ions bombarding the walls is then E i a few T e .Charge uncovering is treated quan-titatively in Chapter 2,and sheaths in Chapter 6.Figure 1.11shows sheath formation as obtained from a particle-in-cell (PIC)plasma simulation.We use PIC results throughout this book to illustrate various dis-charge phenomena.In this simulation,the left wall is grounded,the right wall is ﬂoating (zero net current),and the positive ion density is uniform and constant in time.The electrons are modeled as N sheets having charge-to-mass ratio Àe =mFIGURE 1.9.Electron distribution function in a weakly ionized discharge.1.2PLASMAS AND SHEATHS 1112INTRODUCTION(b)FIGURE1.10.The formation of plasma sheaths:(a)initial ion and electron densities andsheath.potential;(b)densities,electricﬁeld,and potential after formation of the Array FIGURE1.11.PIC simulation of positive ion sheath formation:(a)v x–x electron phase space,with horizontal scale in meters;(b)electron density n e;(c)electricﬁeld E x;(d)potential F;(e)electron number N versus time t in seconds;(f)right hand potential V r versus time t.that move in one dimension (along x )under the action of the time-varying ﬁelds pro-duced by all the other sheets,the ﬁxed ion charge density,and the charges on the walls.Electrons do not collide with other electrons,ions,or neutrals in this simu-lation.Four thousand sheets were used with T e ¼1V and n i ¼n e ¼1013m À3at time t ¼0.In (a ),(b ),(c ),and (d ),we,respectively,see the v x –x electron phase space,electron density,electric ﬁeld,and potential after the sheath has formed,at t ¼0.77m s.The time history of N is shown in (e );40sheets have been lost to form the sheaths.Figures 1.11a –d show the absence of electrons near each wall over a sheath width s %6mm.Except for ﬂuctuations due to the ﬁnite N ,the ﬁeld in the bulk plasma is near zero,and the ﬁelds in the sheaths are large and point from the plasma to the walls.(E x is negative at the left wall and positive at the right wall to repel plasma electrons.)The potential in the center of the discharge is V p %2:5V and falls to zero at the left wall (this wall is grounded by deﬁnition).The potential at the right wall is also low,but we see in (f )that it oscillates in time.We will see in Chapter 4that these are plasma oscillations .We would not see them if the initial sheet positions and velocities were chosen exactly symmetrically about the midplane,or if many more sheets were used in the simulation.If the ions were also modeled as moving sheets,then on a longer timescale we would see ion acceleration within the sheaths,and a consequent drop in ion density near the walls,as sketched in Figure 1.10b .We return to this in Chapter 6.The separation of discharges into bulk plasma and sheath regions is an important paradigm that applies to all discharges.The bulk region is quasi-neutral,and both instantaneous and time-averaged ﬁelds are low.The bulk plasma dynamicsare FIGURE 1.11.(Continued ).1.2PLASMAS AND SHEATHS 1314INTRODUCTIONdescribed by diffusive ion loss at high pressures and by free-fall ion loss at low pressures.In the positive space charge sheaths,highﬁelds exist,leading to dynamics that are described by various ion space charge sheath laws,including low-voltage sheaths and various high-voltage sheath models,such as collisionless and collisional Child laws and their modiﬁcations.The plasma and sheath dynamics must be joined at their interface.As will be seen in Chapter6,the usual joining condition is to require that the mean ion velocity at the plasma-sheath edge be equal to the ion-sound(Bohm)velocity:u B¼(e T e=M)1=2,where e and M are the charge and mass of the ion,respectively,and T e is the electron temperature in volts.1.3DISCHARGESRadio Frequency DiodesCapacitively driven radio frequency(rf)discharges—so-called rf diodes—are commonly used for materials processing.An idealized discharge in plane parallel geometry,shown in Figure1.12a,consists of a vacuum chamber containing two planar electrodes separated by a spacing l and driven by an rf power source.The sub-strates are placed on one electrode,feedstock gases are admitted toﬂow through the discharge,and efﬂuent gases are removed by the vacuum pump.Coaxial discharge geometries,such as the“hexode”shown in Figure1.12b,are also in widespread use. Typical parameters are shown in Table1.1.The typical rf driving voltage is V rf¼100–1000V,and the plate separation is l¼2–10cm.When operated at low pressure,with the wafer mounted on the powered electrode,and used to remove substrate material,such reactors are commonly called reactive ion etchers (RIEs)—a misnomer,since the etching is a chemical process enhanced by energetic ion bombardment of the substrate,rather than a removal process due to reactive ions alone.For anisotropic etching,typically pressures are in the range10–100mTorr, power densities are0.1–1W/cm2,the driving frequency is13.56MHz,and mul-tiple wafer systems are common.Typical plasma densities are relatively low, 109–1011cm23,and the electron temperature is of order3V.Ion acceleration ener-gies(sheath voltages)are high,greater than200V,and fractional ionization is low. The degree of dissociation of the molecules into reactive species is seldom measured but can range widely from less than0.1percent to nearly100percent depending on gas composition and plasma conditions.For deposition and isotropic etch appli-cations,pressures tend to be higher,ion bombarding energies are lower,and fre-quencies can be lower than the commonly used standard of13.56MHz.The operation of capacitively driven discharges is reasonably well understood. As shown in Figure1.13for a symmetrically driven discharge,the mobile plasma electrons,responding to the instantaneous electricﬁelds produced by the rf driving voltage,oscillate back and forth within the positive space charge cloud of the ions.The massive ions respond only to the time-averaged electricﬁelds.Oscil-lation of the electron cloud creates sheath regions near each electrode that containnet positive charge when averaged over an oscillation period;that is,the positive charge exceeds the negative charge in the system,with the excess appearing within the sheaths.This excess produces a strong time-averaged electric ﬁeld within each sheath directed from the plasma to the electrode.Ions ﬂowing out of the bulk plasma near the center of the discharge can be accelerated by the sheath ﬁelds to high energies as they ﬂow to the substrate,leading to energetic-ion enhanced processes.Typical ion-bombarding energies E i can be as high as V rf =2for symmetric systems (Fig.1.13)and as high as V rf at the powered electrode for asymmetric systems (Fig.1.12).A quantitative description of capacitive discharges is given in Chapter11.FIGURE 1.12.Capacitive rf discharges in (a )plane parallel geometry and (b )coaxial “hexode”geometry (after Lieberman and Gottscho,1994).1.3DISCHARGES 15。

A cryogen-free dilution refrigerator based Josephson qubit measurement system(2012年中科院物理所)

A cryogen-free dilution refrigerator based Josephson qubit measurement systemYe Tian, H. F. Yu, H. Deng, G. M. Xue, D. T. Liu et al.Citation: Rev. Sci. Instrum. 83, 033907 (2012); doi: 10.1063/1.3698001View online: /10.1063/1.3698001View Table of Contents: /resource/1/RSINAK/v83/i3Published by the American Institute of Physics.Related ArticlesDynamic shear stress and heat transfer of solid hydrogen, deuterium, and neonJ. Appl. Phys. 111, 083513 (2012)A simple device for dielectric spectroscopy of polymers with temperature regulation close to 300 K based on a Peltier junctionRev. Sci. Instrum. 83, 043903 (2012)Thermal contact conductance of demountable in vacuum copper-copper joint between 14 and 100 KRev. Sci. Instrum. 83, 034902 (2012)Solar adsorption cooling system: An overviewJ. Renewable Sustainable Energy 4, 022701 (2012)A 17 T horizontal field cryomagnet with rapid sample change designed for beamline useRev. Sci. Instrum. 83, 023904 (2012)Additional information on Rev. Sci. Instrum.Journal Homepage: Journal Information: /about/about_the_journalTop downloads: /features/most_downloadedInformation for Authors: /authorsREVIEW OF SCIENTIFIC INSTRUMENTS83,033907(2012)A cryogen-free dilution refrigerator based Josephson qubit measurement systemY e Tian,1H.F.Yu,1H.Deng,1G.M.Xue,1D.T.Liu,1Y.F.Ren,1G.H.Chen,1D.N.Zheng,1 X.N.Jing,1Li Lu,1S.P.Zhao,1and Siyuan Han21Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy ofSciences,Beijing100190,China2Department of Physics and Astronomy,University of Kansas,Lawrence,Kansas66045,USA(Received14January2012;accepted9March2012;published online30March2012)We develop a small-signal measurement system on cryogen-free dilution refrigerator which is suitable for superconducting qubit studies.Cryogen-free refrigerators have several advantages such as less manpower for system operation and large sample space for experiment,but concern remains about whether the noise introduced by the coldhead can be made sufﬁciently low.In this work,we demon-strate some effective approaches of acoustic isolation to reduce the noise impact.The electronic circuit that includes the current,voltage,and microwave lines for qubit coherent state measurement is described.For the current and voltage lines designed to have a low pass of dc-100kHz,we show that the measurements of Josephson junction’s switching current distribution with a width down to1nA, and quantum coherent Rabi oscillation and Ramsey interference of the superconducting qubit can be successfully performed.©2012American Institute of Physics.[/10.1063/1.3698001]I.INTRODUCTIONExperimental studies of superconducting qubits require mK temperature environment with extremely low electro-magnetic(EM)noise level,so that coherent quantum states of qubits can be prepared,maintained,and controlled and their delicate coherent evolution can be monitored and measured.1–4So far,most of these experiments are performed using dilution refrigerators that use liquid He4as cryogen for theﬁrst-stage cooling.However,for such traditional wet systems,there are several obvious disadvantages.For in-stance,even“low-loss”Dewars require reﬁlling every few days,therefore it is not only more expensive but also re-quires more manpower,infrastructure,and time to conduct experiments.Also,the need for a narrow neck in the helium Dewar to keep the boil-off to an acceptable level means that the space available for experimental wiring and other exper-imental services is limited.Moreover,the cold vacuum seal also means hermetically sealed and cryogenically compatible wiring feedthroughs are required in addition to the room tem-peratureﬁttings.There has been much recent interest in the dry dilu-tion refrigerators which use pulse-tube coolers to provide the ﬁrst-stage cooling instead of the liquid cryogen.For these dry systems,the above mentioned disadvantages are avoided. Namely,they need much less manpower to operate and have a much larger sample space.The smaller overall size of the systems is also convenient for magnetic shielding and other lab-space arrangements.In addition,they do not rely on liq-uid He4cryogen which is becoming a more expensive natural resource.Presently,there are still less users for the dry system than those for the wet system.A main concern about using pulse-tube based dilution refrigerators for sensitive small sig-nal measurements is whether noises(vibration,electrical,and acoustic)introduced by the coldhead is sufﬁciently low.In this paper,we describe the design,construction,and charac-terization of a system built on an Oxford DR200cryogen-free dilution refrigerator suitable for experiments that are ex-tremely sensitive to their electromagnetic environments.The paper is organized as follows.Weﬁrst describe the mechan-ical constructions which reduce the acoustic vibrations to a very low level.We then present the electronic measurement setup that includes variousﬁltering,attenuation,and ampliﬁ-cation for different parts of the qubit quantum state prepara-tion and measurement.Finally,we show that the system is adequate for studying coherent quantum dynamics of su-perconducting qubits by demonstrating Rabi oscillation and Ramsey fringe in an Al superconducting phase qubit.II.MECHANICAL CONSTRUCTIONFigure1(a)shows the front view of our system with the DR200refrigerator installed on an aluminum-alloy frame near the center.The refrigerator can reach its base tempera-ture of8mK and temperatures below20mK,respectively, before and after all electronic components and measurement lines described below are installed.It has a prolonged ver-sion compared to the Oxford’s standard design and has a large sample space of25cm in diameter and28cm in height.To reduce vibrations coupled from theﬂoor,the aluminum-alloy frame is placed on four0.8cm thick rubber stands.The re-frigerator can be attached to the frame via an air-spring sys-tem to provide further vibration isolation.The turbo pump, originally placed on the top of the refrigerator,is moved to the other side of the wall in the next room and is connected to the fridge by a stainless steel pipe and a1m long bellows as can be seen in Fig.1(b).Both the pipe and the bellows have the same diameter as that of the inlet of the turbo pump. This setup proves signiﬁcantly reducing the vibrations from the turbo pump.Furthermore,the rotary valve is separated0034-6748/2012/83(3)/033907/5/$30.00©2012American Institute of Physics83,033907-1FIG.1.Photos of the cryogen-free DR200dilution refrigerator system suitable for qubit quantum-state measurements.(a)Front view.(b)Top view.The fridge is installed on an aluminum-alloy frame with double acoustic isolation from the ground using rubber stands and air springs.The turbo pump and rotary valve are mechanically decoupled from the fridge.The fridge is also electrically isolated from the pumps,the control instruments,and the gas lines.The thick red arrow in (b)indicates where an accelerometer sensor is placed for vibration measurement.from the insert and securely attached to the wall,as can also be seen in Fig.1(b).Soft plastic hoses are used for the connec-tions to the DR unit wherever needed.Other equipments,in-cluding the forepump,the compressor (dry pump),the pulse-tube refrigerator (PTR)compressor,and a water cooler are all located in the next room.The overall arrangements of the sys-tem are schematically shown and further explained in Fig.2.Vibration levels of the system are measured using an ac-celerometer in three cases:Namely,the whole system is off,only the turbo pump is on,and both the turbo pump and the PTR are on.The results are shown in Fig.3.The accelerom-eter is manufactured by Wilcoxon Research (Model 731)and its sensor is placed on the top of the refrigerator,as indicated by a thick red arrow in Fig.1(b),which measures the verti-cal acceleration of the system.The sensor is connected to a preampliﬁer with a 450-Hz low-pass ﬁlter.The output volt-age signal of the preampliﬁer (1kV corresponds to 9.8m/s 2)FIG.2.Schematic overall arrangement of the cryogen-free DR200dilution refrigerator measurement system.(1)Aluminum-alloy frame;(2)PTR cold-head;(3)and (4)pumping line;(5)bellows assembly;(6)turbo pump;(7)rotary valve;(8)compressor;(9)forepump;(10)LN2coldtrap;(11)PTR compressor;(12)and (13)electrically isolated gas line and connecters;(14)rubber stands;(15)air-spring system (optional);(16)sand bag;(17)trilayer μ-metal shielding.Thin blue lines represent the gas lines.is then measured by a spectrum analyzer.In its power spec-tral density mode,we directly obtain the acceleration “power”spectral density,which has the unit (m/s 2)2/Hz,or the corre-sponding data presented in unit (m/s 2)/√Hz,which we call acceleration spectral density.The velocity spectral density shown in Fig.3in unit (m/s)/√Hz are the latter data divided by ωand averaged over 400measurements in each case.The baseline in Fig.3(bottom line)decreases mono-tonically from 10−6(m/s)/√Hz at low frequency (<5Hz)to 10−9(m/s)/√Hz at high frequency (>200Hz),which is comparable to the data recorded in several scanning tunneling microscopy (STM)labs around the world.5As a result of the separation of the turbo pump from the main body of the refrigerator,we see that the veloc-ity spectral density increases only slightly when theturboFIG.3.Velocity spectral density of the dilution refrigerator system measured under three conditions:The whole system is off (bottom line),only the turbo pump is on (middle line),and both the turbo pump and the PTR are on (top line),respectively.See text for measurement details.Peaks at 50Hz and its harmonics and subharmonics are due to power line interference (not due to mechanical vibrations).FIG.4.Diagram of the electronic measurement system.Typical three kinds of the measurement lines are shown starting from the left side of the diagram:The qubit ﬂux bias and SQUID-detector current lines,the SQUID-detector voltage lines,and the microwave/fast-pulse lines.pump is switched on (middle line).On the other hand,it increases signiﬁcantly,especially above about 100Hz,when the PTR is also running (top line).This is unavoidable since the PTR is mechanically integrated to the body of the fridge.At f >200Hz,the data are approximately two orders of magnitude higher than the baseline.The results presented in Sec.IV below show that this level of vibration has negligible effect on the control and measurement of the coherent quan-tum dynamics of superconducting phase qubits.III.ELECTRONIC SETUPThe electrical measurement circuit includes three types of lines:The current bias lines,the voltage sensing lines,and the microwave/fast-pulse lines,which are shown schemat-ically in Fig.4.The current and voltage lines from room temperature to low temperature,which are used for the qubit ﬂux bias or superconducting quantum interference device (SQUID)-detector current bias and the SQUID-detector voltage measurement,are composed of ﬂexible coax-ial cables,electromagnetic interference (EMI)ﬁlters,resis-tance/capacitance (RC)ﬁlters,and copper powder ﬁlters 6,7down to the sample platform.Flexible coaxial cables man-ufactured by GVL Cryoengineering with a bandwidth of dc to 300MHz are used.The cables have φ0.65mm CuNi outer conductor,teﬂon dielectric,and central conductors made of ultra-low-temperature-coefﬁcient φ0.1mm brass Ms63(used above the 4K plate)and of φ0.1mm superconducting NbTi (used below the 4K plate).EMI ﬁlters placed outside the fridge at the room temperature are VLFX-470(VLFX)low-pass ﬁlters manufactured by MiniCircuits,which are used to ﬁltering out high frequency noises from room temperature lines.The characteristic impedance of the coaxial ﬁlter VLFX is 50 and the passing band of the ﬁlter is dc to 470MHz with attenuation greater than 40dB between 2and 20GHz.RC ﬁlters are inserted into the coaxial cables and are ther-mally anchored to the 4K plate.All RC ﬁlters have a 3dB cutoff frequency of 100kHz.To reduce joule heating R (C)is chosen to be 1k (2040pF)and 10k (204pF)for the cur-rent and voltage leads,respectively.The copper powder ﬁltersare made following the technique developed by Lukashenko and Ustinov.7Their 3dB cutoff frequency is around 80MHz and has more than 60dB attenuation at 1GHz.Their typ-ical characteristic and ﬁnal appearance of these ﬁlters are shown in Fig.5and the inset.These copper powder ﬁlters are mounted next to the sample platform which is at the mixing chamber temperature.Low-noise preampliﬁers are used in the voltage lines of the detector SQUIDs.These preampliﬁers,with a gain of 1000,are made using two “analog devices”AD624instru-mentation ampliﬁers (gains set to 10and 100,respectively)in series.The bandwidth of these preamps is 100kHz and the noise characteristic is shown in Fig.6.Finally,the microwave lines,shown schematically in Fig.4,are composed of 2.2mm diameter semirigid coaxial cables manufactured by Keycom with non-magnetic stainless steel inner/outer conductors with MiniCircuits attenuators (frequency range 0–18GHz)to in-crease signal-to-noise ratio.The total attenuation coefﬁcient in each line is typically 40dB.FIG.5.Typical attenuation versus frequency characteristic of the copper powder ﬁlters.The attenuation at 120MHz is about 3dB,and is more than 60dB above 1GHz.The length of ﬁlter is 7cm as is shown in the inset.FIG.6.Noise characteristic of a voltage preampliﬁer with gain of 1000made from two AD624instrumentation ampliﬁers in series.The noise spectrum density is less than 10nV rms/√Hz (refer to input)above ∼10Hz up to 100kHz (ﬂat part above 1.6kHz not shown).The inset shows the ﬁnal as-sembly (the longer one)together with that of an isolation ampliﬁer with unity gain (the shorter one).All coaxial cables and attenuators are thermally anchored to various temperature stages (namely,on the 70K,4K,still,100mK,and mixing chamber plates).The thermal anchors for the ﬂexible coaxial cables are made by two copper plates with a 3.5cm section of coaxial cables clamped between them.As can be seen in Figs.1(a)and 1(b),a smaller EM shielding box (Faraday cage)made of cold-rolled steel sheet is placed near the top of the fridge,in which EMI ﬁlters and pream-pliﬁers are located.A trilayer μ-metal magnetic shield,also illustrated in Fig.2,is used to reduce the ambient static ﬁeld to about 20nT.The sample holder has twelve 50 coplanar waveguides (CPWs)allowing signals with frequencies up to 18GHz to pass through with minimal reﬂections.The fridge is galvanically isolated from the vacuum pumps,the control instruments,and gas lines so that the system can be electri-cally connected to a dedicated ground post.We also use an optical coupler in the control line to achieve galvanic isola-tion between the refrigerator and the control rack (see Fig.1).Our tests showed that this setup is adequate for measur-ing coherent quantum dynamics of Josephson qubit circuits as described in detail below.IV .QUANTUM COHERENT-STATE MEASUREMENTSIn order to qualify our system for qubit experiments,we chose to measure coherent dynamics of a superconducting phase qubit,which is extremely sensitive to its EM environ-ment.As an initial characterization of the electronic system,we measured the switching current distribution P (I )of a Nb dc-SQUID with the loop inductance much smaller than the Josephson inductance of the junctions so that the SQUID be-haves as a single junction with critical current I c tunable by applying a magnetic ﬁeld.8From the measured width σof P (I )versus temperature,we found that σcontinuously de-crease to as low as 4nA at 20mK by reducing I c and as low as 1nA near 1K due to phase diffusion 9,10indicating a current noise level below 1nA in our measurement circuit.The ﬂux biased phase qubit had similar layout and pa-rameters as that described in Ref.11and was coupled to an asymmetric dc-SQUID to readout its quantum state.A current bias line was used to apply an external magnetic ﬂux to the qubit loop which controls the shape of the potential energy landscape and the level separation E 10between the ground and ﬁrst excited states of the qubit.For a given E 10,a short res-onant microwave pulse of variable length with frequency f 10=E 10/h was applied,which coherently transfers population between the ground state and the ﬁrst excited state.Conse-quently,we observed Rabi oscillations by keeping the ampli-tude of the microwave ﬁeld constant while varying the dura-tion of the modulation pulses.Data obtained with microwave frequency of about 16GHz are shown in Fig.7(a)as symbols.A simple ﬁt to an exponentially damped sinusoidal function yields a decay time of 70ns.In Fig.7(b),the Rabi frequency versus microwave amplitude,which shows the expected linear dependence,is displayed.FIG.7.(a)Rabi oscillation measured from an rf-SQUID type phase qubit made of Al Josephson junction (symbols).The applied microwave frequency is ∼16GHz and a decay time of 70ns is obtained from the exponentially damped sinusoidal oscillation ﬁt (line).(b)Rabi frequency versus microwave amplitude (symbols).The line is a guide to the eye.FIG.8.(a)Ramsey fringe measured from an rf-SQUID type phase qubit made of Al Josephson junction(symbols).The applied microwave frequency is ∼16GHz and a decay time of38ns is obtained from the exponentially damped sinusoidal oscillationﬁt(line).(b)Ramsey frequency versus detuning(symbols). The line is a guide to the eye.Ramsey interference was also observed in the phase qubitby applying twoπ/2pulses,separated by a time delayτ.Manipulation of the qubit state for Ramsey pulse sequencecan be explained in terms of the Bloch sphere and Blochvectors.3Theﬁrstπ/2pulse rotates the qubit state vectorto the x-y plane,where it is allowed to evolve around the zaxis freely for a duration ofτ.Subsequently,the secondπ/2pulse is applied which is followed immediately by qubit statereadout.When the microwave frequency is detuned slightlyby a mountδf away from f10,theﬁnal state of the qubit atthe end of the secondπ/2pulse will be a superposition ofthe ground(theﬁrst excited)state with probability ampli-tude cos2πδfτ(sin2πδfτ).The sinusoidal dependence of thestate probabilities on time can then be obtained by varyingτ.Figure8(a)shows the measured Ramsey fringe with a periodof1/δf forδf=100MHz.Fitting the data to exponentiallydamped sinusoidal oscillation leads to a decay(dephasing)time of T∗2=38ns.The linear dependence of the Ramseyfrequency on detuning can be seen in Fig.8(b).These results are comparable to those obtained from the same phase qubit using a qubit-experiment-qualiﬁed wet dilution refrigerator and thus clearly demonstrate that our cryogen-free dilution refrigerator provides a good low-temperature,low-noise platform for delicate experiments such as measuring the coherent quantum dynamics of Josephson phase qubit described above.What is worthy to mention is that the overall design and construction of our sys-tem,built in a laboratory which is not electromagnetically shielded,are relatively easy to achieve with minimal addi-tional cost.The realization of the present system should be useful also for the quantum-state measurements at low tem-peratures of many other physical systems whose properties and dynamics are very sensitive toﬂuctuations in their envi-ronment.ACKNOWLEDGMENTSWe are grateful to Junyun Li of Oxford Instruments Shanghai Ofﬁce for his continuous support in this work and to H.J.Gao,L.Shan,and C.Ren for their kind help dur-ing vibration measurements.The work at the Institute of Physics was supported by the National Natural Science Foun-dation of China(Grant Nos.10874231and11104340)and the Ministry of Science and Technology of China(Grant Nos. 2009CB929102and2011CBA00106).1Y.Makhlin,G.Schön,and A.Shnirman,Rev.Mod.Phys.73,357(2001). 2A.Wallraff,A.Lukashenko,C.Coqui,A.Kemp,T.Duty,and A.V. Ustinov,Rev.Sci.Instrum.74,3740(2003).3J.Clarke and F.K.Wilhelm,Nature(London)453,1031(2008).4J.Q.You and F.Nori,Nature(London)474,589(2011).5J.E.Hoffman,Ph.D.dissertation,University of California,Berkeley, 2003).6J.M.Martinis,M.H.Devoret,and J.Clarke,Phys.Rev.B35,4682 (1987).7A.Lukashenko and tinov,Rev.Sci.Instrum.79,014701(2008). 8H.F.Yu,X.B.Zhu,Z.H.Peng,W.H.Cao,D.J.Cui,Y.Tian,G.H.Chen, D.N.Zheng,X.N.Jing,Li Lu,S.P.Zhao,and S.Y.Han,Phys.Rev.B81, 144518(2010).9S.-X.Li,W.Qiu,S.Han,Y.F.Wei,X.B.Zhu,C.Z.Gu,S.P.Zhao,and H.B.Wang,Phys.Rev.Lett.99,037002(2007).10H.F.Yu,X.B.Zhu,Z.H.Peng,Y.Tian,D.J.Cui,G.H.Chen,D.N.Zheng, X.N.Jing,Li Lu,S.P.Zhao,and S.Han,Phys.Rev.Lett.107,067004 (2011).11M.Neeley,R.C.Bialczak,M.Lenander,E.Lucero,M.Mariantoni, A.D.O’Connell,D.Sank,H.Wang,M.Weides,J.Wenner,Y.Yin, T.Yamamoto,A.N.Cleland,and J.M.Martinis,Nature(London)467, 570(2010).。

计算机专业英语选择

Multiple 11. The keyboard, mouse, monitor, and system unit are:hardware output devices storage devices software2. Programs that coordinate computer resources, provide an interface, and run applications are known as:application programs operating systemsstorage systems utility programs3. A browser is an example of a:basic application specialized programsystem application utility program4. Although not as powerful as a supercomputer, this type of computer is capable of great processing speeds and data storage.mainframe media center midrange netbook5. The smallest type of microcomputer:netbook handheld midrange tablet PC6. RAM is a type of:computer memory network secondary storage7. Unlike memory, this type of storage holds data and programs even after electrical power to the computer system has been turned off.primary RAM ROM secondary8. The type of file created by word processors to save, for example, memos, term papers, and letters.database document presentation worksheet9. The change in connectivity that uses the Internet and the Web to shift many computer activities from a user’s computer to computers on the Internet.cloud computing high definition network USB10. The largest network in the world is [the]:Facbeook Internet Web USBMultiple 21. The network that connects computers all over the world.CERN Internet LAN Web2. The rules for exchanging data between computers.DSL protocols Web WWW3. Client-based e-mail accounts require this special program to be installed on your computer.e-mail client hyperlink Java utility4. Communities of individuals who share a common interest typically create Facebook:clients groups pages profiles5. E-mail that does not require an e-mail program installed on a user's computer is known as:blog podcast Webmail utility6. A very well-known microblog.LinkedIn MySpace Twitter Wikipedia7. These programs continually look for new information and update search services’ database programs.filters IM spiders wikis8. A type of search engine that submits requests to other search engines, organizes their responses, eliminates duplicate responses, orders hits, and then provides an edited list.directory search ISPmetasearch engine specialized search engine9. This is the Internet’s equivalent to traditional cash.digital cash e-commerce icash Internetdollars10. Using file transfer utility software, you can copy files to your computer from specially configured servers on the Internet. This is called:downloading filtering blogging uploadingMultiple 31. This type of software works with end users, application software, and computer hardware to handle the majority of technical details.application general purpose system utility2. A rectangular area that can contain a document, program, or message.dialog box form frame window3. Programs that create text-based documents.DBMS suites spreadsheets word processors4. Programs that organize, analyze, and graph numeric data such as budgets and financial reports.DBMS suites spreadsheets word processors5. In a spreadsheet, the intersection of a row and column creates a:cell formula function label6. A collection of related data that is the electronic equivalent of a file cabinet.cell database document table7. A database tool that will quickly rearrange a table’s records according toa selected field.filter sort spreadsheet word processor8. Programs that combine a variety of visual objects to create attractive, visually interesting presentations.DBMS presentation graphics spreadsheet word processor9. The primary disadvantage of this type of package is that the capabilities of each function are not as extensive as in individual programs.integrated office software utility10. A type of suite stored at a server on the Internet and available anywhere through Internet access.cloud integrated office utilityMultiple 41. These specialized graphics programs combine text and graphics to create publications of professional quality.desktop publishing programs image editorsimage galleries illustration programs2. Also known as drawing programs.desktop publishing programs image editorsimage galleries illustration programs3. Graphics programs used to create and edit vector images.desktop publishing programs image editorsimage galleries illustration programs4. An essential multimedia feature that allows user participation.Flash interactivity immersion raster5. Special programs used to create multimedia presentations.desktop publishing programs Flash editorsimage editors multimedia authoring programs6. A widely used interactive animation application from Adobe.ACTION Flash Fuzzy WYSIWYG7. Programs for Web site design and HTML coding are called Web page editors orapps HTML editors VR programs Web editors8. This area of artificial intelligence is also known as expert systems.acoustics knowledge-based systems robotics virtual reality9. A type of artificial intelligence that uses a database to provide assistance to users.acoustics expert systems robotics virtual reality10. Another name for the database used in expert systems that contains specific facts and rules.access table expert table knowledge base rule baseMultiple 51. What type of software works with users, application software, and computer hardware to handle the majority of technical detailsdapplication desktop Linux system2. The programs that convert programming instructions written by programmers into a language that computers understand and process are language:converters linguists managers translators3. The ability to switch between different applications stored in memory is called:diversion multitasking operational interferenceprogramming4. Graphic representations for a program, type of file, or function:app icon image software5. This operating system feature is controlled by a mouse and changes shape depending on its current function.dialog box menu mouse pointer6. The operating system based on Linux, designed for Netbook computers, and focused on Internet connectivity through cloud computing:Chrome Mac Unix Windows7. The mobile operating system developed by Apple and originally called iPhone OS:Android BlackBerry OS IOS Mac OS8. A utility program that makes copies of files to be used in case the originals are lost or damaged:Backup and Restore Disk Cleanup Disk Defragmenter Compactor9. A troubleshooting utility that identifies and eliminates nonessential files, frees up valuable disk space, and improves system performance:Backup and Restore Disk Cleanup Disk Defragmenter Compactor 10. Windows makes it easy to update drivers with Windows:Backup Restore Driver UpdateMultiple 61. This container houses most of the electrical components for a computer system.carrier package system board system unit TV tuner2. Similar to notebooks, this system unit specializes in on-the-go Web browsing and e-mail access.chassis desktop media center netbook3. Computers can only recognize this type of electronic signal.analog bus digital maximum4. The main or motherboard is also known as the:computer board processor mobile system system board5. How many bytes can a 32-bit-word computer access at one time1 48 166. In a microcomputer system, the central processing unit is contained on a single:bus chip module RAM7. This type of memory divides large programs into parts and stores the parts on a secondary storage device.direct expanded random-access virtual8. Also known as NIC, this adapter card is used to connect a computer to a:AIA expansion graphics network9. This provides a pathway to connect parts of the CPU to each other.bus Plug and Play wired wireless10. Older ports that have largely been replaced by faster, more flexible ports are called:buses expandable legacy renderedMultiple 71. Most keyboards use an arrangement of keys known as:Alpha Daisy OptiKey QWERTY2. The device that controls a pointer displayed on the monitor.cord mouse printer scanner3. Also known as a roller ball, this device controls the pointer by rotatinga ball with your thumb.trackball joystick cordless mouse stylus4. The type of screen that can be touched with more than one finger and supports zooming in and out by pinching and stretching your fingers.digital dynamic multitouch OLED5. Flatbed and document are types of:headsets HDTVs monitors scanners6. Device used by banks to automatically read those unusual numbers on the bottom of checks and deposit slips.MICR FDIC OMR UPC7. The most widely used audio-input device.mouse VR microphone TFT8. The monitor feature that specifies how often a displayed image is updated.aspect ratio dot pitch refresh rateresolution rate9. Handheld, book-sized devices that display text and graphics.e-book readers HDTV lasers whiteboards10. This technology allows television stations to broadcast their programming directly to smartphones, computers, and digital media players.CRT HDTV LED Mobile DTVMultiple 81. RAM is sometimes referred to as:primary storage ratio active memoryread only memory secondary storage2. The actual physical material that holds the data and programs.primary storage media disk access3. Measures how tightly these charges can be packed next to one another on the disk.density cylinders tracks sectors4. When a read/write head makes contact with the hard disk’s surface, it causesa head:crash land pit scratch5. This hard-disk performance enhancement anticipates data needs.disk caching file compression file decompression RAID6. This type of storage uses pits and lands to represent 1s and 0s.cloud hard disk optical solid state7. DVD stands for:digital versatile disc digital video datadynamic versatile disc dynamic video disc8. USB drives are also known as:flash drives optical drives ports universal state bus9. An organizational strategy to promote efficient and safe use of data across the networks.cloud dynamic data mission statemententerprise storage system RAID10. A mass storage device that provides access to data archived on tapes.file system NAS RAID system tape libraryMultiple 91. The concept related to using computer networks to link people and resources.connectivity GPS TCP/IP Wi-Fi2. A high-frequency transmission cable that delivers television signals as well as connects computers in a network.coaxial hi def 3-D twisted pair3. A short-range radio communication standard that transmits data over short distances of up to approximately 30 feet.Bluetooth broadband DSL TCP/IP4. The speed with which a modem transmits data is called its:digital velocity dynamic rate modular rating transfer rate5. The bandwidth typically used for DSL, cable, and satellite connections to the Internet.baseband broadband medium band voiceband6. Every computer on the Internet has a unique numeric address called a(n):IP address DNS broadcast packet7. Sometimes referred to as a LAN adapter, these expansion cards connect a computer to a network.PCMCIA NIC server VPN8. A device that allows one LAN to be linked to other LANs or to larger networks.IDS network gateway PAN switch9. Typically using Wi-Fi technology, these wireless access points are typically available from public places such as coffee shops, libraries, bookstores, colleges, and universities.hotspots extranets PANs LANs10. Star, tree, and mesh are three types of network:topologies protocols strategies devicesMultiple 101. The three primary privacy issues are accuracy, property, and:access ethics ownership security2. To easily get names, addresses, and other details about a person using only his or her telephone number, government authorities and others use a(n):adware cookie keystroke logger reverse directory worm3. Browsers store the locations of sites visited in a:history menu tool bar firewall4. The browser mode that eliminates history files and blocks most cookies.detect insert privacy sleep5. The information that people voluntarily post in social networking sites, blogs, and photo- and video-sharing sites is used to create their:access approval firewall online identity phish6. Computer criminals who specialize in stealing, trading, and using stolen credit cards over the Internet are known as:carders card scammers cyber traders identity thieves7. Programs that come into a computer system disguised as something else are called:Trojan horses viruses Web bugs zombies8. The use of the Internet, cell phones, or other devices to send or post content intended to hurt or embarrass another person is known as:cyber-bullying online harassmentsocial media discrimination unethical communication9. Special hardware and software used to control access to a corporation’s private network is known as a(n):antivirus program communication gatefirewall spyware removal program10. To prevent copyright violations, corporations often use:ACT DRM VPN WPAMultiple 111. Which of the basic organizational functions records all financial activity from billing customers to paying employeesaccounting marketing production research2. What managerial level has information flow that is vertical, horizontal, and externaltop supervisory middle foreman3. Which computer-based information system uses data from TPS and analytical tools to support middle managersESS MIS DSS TPS4. Accounts payable refers to money the company owes its suppliers for materials and services it has:created exported inventoried received5. What accounting activity keeps track of all summaries of all transactionsbalance sheet general ledgerincome statement inventory control6. What accounting statement lists the overall financial condition of an organizationbalance sheet general ledgerincome statement inventory control7. What type of report is produced at regular intervalsdemand exception inventory periodic8. A DSS consists of four parts: user, system software, decision models, and:application software data operating systemspreadsheets9. What type of worker is involved with the distribution, communication, and creation of informationexecutive foreman information knowledge10. What type of program is designed to schedule, plan, and control project resourcesauditing dtp project managers schedulersMultiple 121. Facts or observations about people, places, things, and events are:data occurrences records tables2. The most basic logical data element such as a single letter, number, or special character is known as a:character element phrase record3. Each record in a database has at least one distinctive field, called the:key field structure type view4. One element of database security is to provide only authorized users with:classes nodes passwords relations5. The bridge between the logical and physical views of the data is provided by:DBMS records SQL tables6. Highly trained computer specialists who interact with the data administration subsystem are known as:DBMS data modelers database administrators relational specialists7. In a network database, each child node may have more than one parent node; this is known as a:hierarchy many-to-many relationshipparent relationship relational relationship8. Connections between parent nodes and child nodes are provided by:characters DBA objects pointers9. Two of the most significant advantages of multidimensional databases over relational databases are processing speed and:conceptualization control format objectification10. Object-oriented databases organize data by classes, attributes, methods, and:objects relations space timeMultiple 131. An information system is a collection of hardware, software, people, procedures, and:data DBMS specialists system analysts2. What is the first phase in the systems life cycleneeds analysis preliminary investigationsystems analysis systems design3. Which phase in the systems life cycle involves installing the new system and training peoplepreliminary investigation systems analysissystem design systems implementation4. This phase in the systems life cycle is concerned about determining system requirements not in design.preliminary investigation systems analysissystem design systems implementation5. Which systems analysis tool shows the relationship between input and output documentschecklist data flow decision table grid chart6. These tools relieve the systems analysts of many repetitive tasks, develop clear documentation, and, for larger projects, coordinate team member activities.automated systems life cycle CASEdata flow analyzers flow charts7. Which systems life cycle phase is concerned with economic, technical, and operational feasibilitypreliminary investigation systems analysissystems design systems implementation8. What type of feasibility evaluates whether the people within the organization will embrace or resist a new systembehavioral economic operational techinical9. Which approach to conversion begins by trying out a new system in only one part of an organizationdirect pilot parallel phased10. An alternative to the systems life cycle approach using powerful development software, small specialized teams, and highly trained personnel.AAD CASE prototyping RADMultiple 141. A program is a list of instructions for the computer to follow to process:data direct logic hardware software2. The major processing steps identified in a top-down program design are called:assembly instructions modules logic3. The programming logic structure in which one program statement follows another.concatenation loop repetition selection4. One of the best ways to code effective programs is to use the three basic logic structures to create:content-markup programs modular languagespseudocode structured programs5. Which step in the six-step programming procedure involves desk checking and searching for syntax and logic errorsprogram design program documentationprogram maintenance program test6. Which step in the six-step programming procedure is the final stepprogram design program documentationprogram test program maintenance7. Unlike traditional systems development, this software development approach focuses less on the procedures and more on defining the relationships between previously defined procedures.2GL context-markup module object-oriented8. Natural languages are considered to be a:high-level language low-level languagemid-level language procedural language9. A compiler converts the programmer’s procedural language program, called the source code, into a machine language code, called the:interpreter code object codestructured code top-down code10. The 4GL languages that enable nonprogrammers to use certain easily understood commands to search and generate reports from a database.query application generator C11 COBOLMultiple 151. People who react to technology by thinking computers are magic boxes capable of solving all kinds of problems that computers really can’t handle are:cynics frustrated naïve proactive2. The type of person that looks at technology in a positive realistic way is:cynical proactive naïve frustrated3. Books, journals, and trade associations are the best sources to help you:develop personal contacts develop specialtieslook for innovative opportunities maintain your computer competency4. If your career is in marketing, it makes sense to develop a specialty in:database desktop publishingprogramming systems analysis and design5. What computer professional repairs and installs computer components and systemscomputer technician data entry workerdesktop publisher software engineer6. What computer professional designs, tests, and researches encryption procedurescryptographer network administratorprogrammer software engineer7. What computer professional uses database management software to determine the most efficient ways to organize and access datacryptographer database administratorprogrammer software engineer8. What computer professional oversees the work of programmers, computer specialists, systems analysts, and other computer professionalsnetwork managersoftware engineer technical writer9. What computer professional creates, tests, and troubleshoots computer programsnetwork manager programmersoftware engineer technical writer10. What computer professional plans and designs information systemsnetwork manager programmersoftware engineer systems analyst。

计算机专业英语选择

Multiple 11. The keyboard, mouse, monitor, and system unit are:hardware output devices storage devices software2. Programs that coordinate computer resources, provide an interface, and run applications are known as:application programs operating systemsstorage systems utility programs3. A browser is an example of a:basic application specialized programsystem application utility program4. Although not as powerful as a supercomputer, this type of computer is capable of great processing speeds and data storage.mainframe media center midrange netbook5. The smallest type of microcomputer:netbook handheld midrange tablet PC6. RAM is a type of:computer memory network secondary storage7. Unlike memory, this type of storage holds data and programs even after electrical power to the computer system has been turned off.primary RAM ROM secondary8. The type of file created by word processors to save, for example, memos, term papers, and letters.database document presentation worksheet9. The change in connectivity that uses the Internet and the Web to shift many computer activities from a user’s computer to computers on the Internet.cloud computing high definition network USB10. The largest network in the world is [the]:Facbeook Internet Web USBMultiple 21. The network that connects computers all over the world.CERN Internet LAN Web2. The rules for exchanging data between computers.DSL protocols Web WWW3. Client-based e-mail accounts require this special program to be installed on your computer.e-mail client hyperlink Java utility4. Communities of individuals who share a common interest typically create Facebook:clients groups pages profiles5. E-mail that does not require an e-mail program installed on a user's computer is known as:blog podcast Webmail utility6. A very well-known microblog.LinkedIn MySpace Twitter Wikipedia7. These programs continually look for new information and update search services’ database programs.filters IM spiders wikis8. A type of search engine that submits requests to other search engines, organizes their responses, eliminates duplicate responses, orders hits, and then provides an edited list.directory search ISPmetasearch engine specialized search engine9. This is the Internet’s equivalent to traditional cash.digital cash e-commerce icash Internet dollars10. Using file transfer utility software, you can copy files to your computer from specially configured servers on the Internet. This is called:downloading filtering blogging uploadingMultiple 31. This type of software works with end users, application software, and computer hardware to handle the majority of technical details.application general purpose system utility2. A rectangular area that can contain a document, program, or message.dialog box form frame window3. Programs that create text-based documents.DBMS suites spreadsheets word processors4. Programs that organize, analyze, and graph numeric data such as budgets and financial reports.DBMS suites spreadsheets word processors5. In a spreadsheet, the intersection of a row and column creates a:cell formula function label6. A collection of related data that is the electronic equivalent of a file cabinet.cell database document table7. A database tool that will quickly rearrange a table’s records according to a selected field.filter sort spreadsheet word processor8. Programs that combine a variety of visual objects to create attractive, visually interesting presentations.DBMS presentation graphics spreadsheet word processor9. The primary disadvantage of this type of package is that the capabilities of each function are not as extensive as in individual programs.integrated office software utility10. A type of suite stored at a server on the Internet and available anywhere through Internet access.cloud integrated office utilityMultiple 41. These specialized graphics programs combine text and graphics to create publications of professional quality.desktop publishing programs image editorsimage galleries illustration programs2. Also known as drawing programs.desktop publishing programs image editorsimage galleries illustration programs3. Graphics programs used to create and edit vector images.desktop publishing programs image editorsimage galleries illustration programs4. An essential multimedia feature that allows user participation.Flash interactivity immersion raster5. Special programs used to create multimedia presentations.desktop publishing programs Flash editorsimage editors multimedia authoring programs 6. A widely used interactive animation application from Adobe.ACTION Flash Fuzzy WYSIWYG7. Programs for Web site design and HTML coding are called Web page editors orapps HTML editors VR programs Web editors8. This area of artificial intelligence is also known as expert systems.acoustics knowledge-based systems robotics virtual reality9. A type of artificial intelligence that uses a database to provide assistance to users.acoustics expert systems robotics virtual reality10. Another name for the database used in expert systems that contains specific facts and rules.access table expert table knowledge base rule baseMultiple 51. What type of software works with users, application software, and computer hardware to handle the majority of technical details?dapplication desktop Linux system2. The programs that convert programming instructions written by programmers into a language that computers understand and process are language:converters linguists managers translators3. The ability to switch between different applications stored in memory is called:diversion multitasking operational interference programming 4. Graphic representations for a program, type of file, or function:app icon image software5. This operating system feature is controlled by a mouse and changes shape depending on its current function.dialog box menu mouse pointer6. The operating system based on Linux, designed for Netbook computers, and focused on Internet connectivity through cloud computing:Chrome Mac Unix Windows7. The mobile operating system developed by Apple and originally called iPhone OS:Android BlackBerry OS IOS Mac OS8. A utility program that makes copies of files to be used in case the originals are lost or damaged:Backup and Restore Disk Cleanup Disk Defragmenter Compactor9. A troubleshooting utility that identifies and eliminates nonessential files, frees up valuable disk space, and improves system performance:Backup and Restore Disk Cleanup Disk Defragmenter Compactor 10. Windows makes it easy to update drivers with Windows:Backup Restore Driver UpdateMultiple 61. This container houses most of the electrical components for a computer system.carrier package system board system unit TV tuner2. Similar to notebooks, this system unit specializes in on-the-go Web browsing and e-mail access.chassis desktop media center netbook3. Computers can only recognize this type of electronic signal.analog bus digital maximum4. The main or motherboard is also known as the:computer board processor mobile system system board 5. How many bytes can a 32-bit-word computer access at one time?1 48 166. In a microcomputer system, the central processing unit is contained on a single:bus chip module RAM7. This type of memory divides large programs into parts and stores the parts ona secondary storage device.direct expanded random-access virtual8. Also known as NIC, this adapter card is used to connect a computer to a:AIA expansion graphics network9. This provides a pathway to connect parts of the CPU to each other.bus Plug and Play wired wireless10. Older ports that have largely been replaced by faster, more flexible ports are called:buses expandable legacy renderedMultiple 71. Most keyboards use an arrangement of keys known as:Alpha Daisy OptiKey QWERTY2. The device that controls a pointer displayed on the monitor.cord mouse printer scanner3. Also known as a roller ball, this device controls the pointer by rotating a ball with your thumb.trackball joystick cordless mouse stylus4. The type of screen that can be touched with more than one finger and supports zooming in and out by pinching and stretching your fingers.digital dynamic multitouch OLED5. Flatbed and document are types of:headsets HDTVs monitors scanners6. Device used by banks to automatically read those unusual numbers on the bottom of checks and deposit slips.MICR FDIC OMR UPC7. The most widely used audio-input device.mouse VR microphone TFT8. The monitor feature that specifies how often a displayed image is updated.aspect ratio dot pitch refresh rate resolution rate 9. Handheld, book-sized devices that display text and graphics.e-book readers HDTV lasers whiteboards10. This technology allows television stations to broadcast their programming directly to smartphones, computers, and digital media players.CRT HDTV LED Mobile DTVMultiple 81. RAM is sometimes referred to as:primary storage ratio active memoryread only memory secondary storage2. The actual physical material that holds the data and programs.primary storage media disk access3. Measures how tightly these charges can be packed next to one another on the disk.density cylinders tracks sectors4. When a read/write head makes contact with the hard disk’s surface, it causes a head:crash land pit scratch5. This hard-disk performance enhancement anticipates data needs.disk caching file compression file decompression RAID6. This type of storage uses pits and lands to represent 1s and 0s.cloud hard disk optical solid state7. DVD stands for:digital versatile disc digital video datadynamic versatile disc dynamic video disc8. USB drives are also known as:flash drives optical drives ports universal state bus9. An organizational strategy to promote efficient and safe use of data across the networks.cloud dynamic data mission statemententerprise storage system RAID10. A mass storage device that provides access to data archived on tapes.file system NAS RAID system tape libraryMultiple 91. The concept related to using computer networks to link people and resources.connectivity GPS TCP/IP Wi-Fi2. A high-frequency transmission cable that delivers television signals as well as connects computers in a network.coaxial hi def 3-D twisted pair3. A short-range radio communication standard that transmits data over short distances of up to approximately 30 feet.Bluetooth broadband DSL TCP/IP4. The speed with which a modem transmits data is called its:digital velocity dynamic rate modular rating transfer rate5. The bandwidth typically used for DSL, cable, and satellite connections to the Internet.baseband broadband medium band voiceband6. Every computer on the Internet has a unique numeric address called a(n):IP address DNS broadcast packet7. Sometimes referred to as a LAN adapter, these expansion cards connect a computer to a network.PCMCIA NIC server VPN8. A device that allows one LAN to be linked to other LANs or to larger networks.IDS network gateway PAN switch9. Typically using Wi-Fi technology, these wireless access points are typically available from public places such as coffee shops, libraries, bookstores, colleges, and universities.hotspots extranets PANs LANs10. Star, tree, and mesh are three types of network:topologies protocols strategies devicesMultiple 101. The three primary privacy issues are accuracy, property, and:access ethics ownership security2. To easily get names, addresses, and other details about a person using only his or her telephone number, government authorities and others use a(n):adware cookie keystroke logger reverse directory worm3. Browsers store the locations of sites visited in a:history menu tool bar firewall4. The browser mode that eliminates history files and blocks most cookies.detect insert privacy sleep5. The information that people voluntarily post in social networking sites, blogs, and photo- and video-sharing sites is used to create their:access approval firewall online identity phish6. Computer criminals who specialize in stealing, trading, and using stolen credit cards over the Internet are known as:carders card scammers cyber traders identity thieves7. Programs that come into a computer system disguised as something else are called:Trojan horses viruses Web bugs zombies8. The use of the Internet, cell phones, or other devices to send or post content intended to hurt or embarrass another person is known as:cyber-bullying online harassmentsocial media discrimination unethical communication9. Special hardware and software used to control access to a corporation’s private network is known as a(n):antivirus program communication gatefirewall spyware removal program10. To prevent copyright violations, corporations often use:ACT DRM VPN WPAMultiple 111. Which of the basic organizational functions records all financial activity from billing customers to paying employees?accounting marketing production research2. What managerial level has information flow that is vertical, horizontal, and external?top supervisory middle foreman3. Which computer-based information system uses data from TPS and analytical tools to support middle managers?ESS MIS DSS TPS4. Accounts payable refers to money the company owes its suppliers for materials and services it has:created exported inventoried received5. What accounting activity keeps track of all summaries of all transactions?balance sheet general ledgerincome statement inventory control6. What accounting statement lists the overall financial condition of an organization?balance sheet general ledgerincome statement inventory control7. What type of report is produced at regular intervals?demand exception inventory periodic8. A DSS consists of four parts: user, system software, decision models, and:application software data operating systemspreadsheets9. What type of worker is involved with the distribution, communication, and creation of information?executive foreman information knowledge10. What type of program is designed to schedule, plan, and control project resources?auditing dtp project managers schedulersMultiple 121. Facts or observations about people, places, things, and events are:data occurrences records tables2. The most basic logical data element such as a single letter, number, or special character is known as a:character element phrase record3. Each record in a database has at least one distinctive field, called the:key field structure type view4. One element of database security is to provide only authorized users with:classes nodes passwords relations5. The bridge between the logical and physical views of the data is provided by:DBMS records SQL tables6. Highly trained computer specialists who interact with the data administration subsystem are known as:DBMS data modelers database administrators relational specialists7. In a network database, each child node may have more than one parent node; this is known as a:hierarchy many-to-many relationshipparent relationship relational relationship8. Connections between parent nodes and child nodes are provided by:characters DBA objects pointers9. Two of the most significant advantages of multidimensional databases over relational databases are processing speed and:conceptualization control format objectification10. Object-oriented databases organize data by classes, attributes, methods, and:objects relations space timeMultiple 131. An information system is a collection of hardware, software, people, procedures, and:data DBMS specialists system analysts2. What is the first phase in the systems life cycle?needs analysis preliminary investigationsystems analysis systems design3. Which phase in the systems life cycle involves installing the new system and training people?preliminary investigation systems analysissystem design systems implementation4. This phase in the systems life cycle is concerned about determining system requirements not in design.preliminary investigation systems analysissystem design systems implementation5. Which systems analysis tool shows the relationship between input and output documents?checklist data flow decision table grid chart6. These tools relieve the systems analysts of many repetitive tasks, develop clear documentation, and, for larger projects, coordinate team member activities.automated systems life cycle CASEdata flow analyzers flow charts7. Which systems life cycle phase is concerned with economic, technical, and operational feasibility?preliminary investigation systems analysissystems design systems implementation8. What type of feasibility evaluates whether the people within the organization will embrace or resist a new system?behavioral economic operational techinical9. Which approach to conversion begins by trying out a new system in only one part of an organization?direct pilot parallel phased10. An alternative to the systems life cycle approach using powerful development software, small specialized teams, and highly trained personnel.AAD CASE prototyping RADMultiple 141. A program is a list of instructions for the computer to follow to process:data direct logic hardware software2. The major processing steps identified in a top-down program design are called:assembly instructions modules logic3. The programming logic structure in which one program statement follows another.concatenation loop repetition selection4. One of the best ways to code effective programs is to use the three basic logic structures to create:content-markup programs modular languagespseudocode structured programs5. Which step in the six-step programming procedure involves desk checking and searching for syntax and logic errors?program design program documentationprogram maintenance program test6. Which step in the six-step programming procedure is the final step?program design program documentationprogram test program maintenance7. Unlike traditional systems development, this software development approach focuses less on the procedures and more on defining the relationships between previously defined procedures.2GL context-markup module object-oriented8. Natural languages are considered to be a:high-level language low-level languagemid-level language procedural language9. A compiler converts the programmer’s procedural language program, called the source code, into a machine language code, called the:interpreter code object codestructured code top-down code10. The 4GL languages that enable nonprogrammers to use certain easily understood commands to search and generate reports from a database.query application generator C11 COBOLMultiple 151. People who react to technology by thinking computers are magic boxes capable of solving all kinds of problems that computers really can’t handle are:cynics frustrated naïve proactive2. The type of person that looks at technology in a positive realistic way is:cynical proactive naïve frustrated3. Books, journals, and trade associations are the best sources to help you:develop personal contacts develop specialtieslook for innovative opportunities maintain your computer competency 4. If your career is in marketing, it makes sense to develop a specialty in:database desktop publishingprogramming systems analysis and design5. What computer professional repairs and installs computer components and systems?computer technician data entry workerdesktop publisher software engineer6. What computer professional designs, tests, and researches encryption procedures?cryptographer network administratorprogrammer software engineer7. What computer professional uses database management software to determine the most efficient ways to organize and access data?cryptographer database administratorprogrammer software engineer8. What computer professional oversees the work of programmers, computer specialists, systems analysts, and other computer professionals?information systems manager network managersoftware engineer technical writer9. What computer professional creates, tests, and troubleshoots computer programs?network manager programmersoftware engineer technical writer10. What computer professional plans and designs information systems?network manager programmersoftware engineer systems analyst。

25MnV钢_零保温_淬火状态下的组织与性能

表２ !１８ｍｍ×６４ｍｍ圆环链的检测结果Ｔａｂｌｅ２Ｔｈｅｅｘａｍｉｎｅｒｅｓｕｌｔｏｆ !１８ｍｍ×６４ｍｍｃｉｒｃｕｌａｒｃｈａｉｎ
试样号１２３４
试验负荷／ｋＮ４１０４１０４１０３９０
伸长率（％）１．６１．６１．５１．２
备注
试样４为焊接处断开，其余试
样均未断
５结论
（１）２５ＭｎＶ钢在８３０～９１０℃淬火，其强度、硬度随淬火温度的增加而升高，９１０℃“零保温”淬火具有较高的强度、硬度。
（２）淬火温度高于８８０℃，２５ＭｎＶ钢 “零保温”淬火的强硬性优于传统保温淬火的。
（３） “零保温”淬火得到极细的板条状马氏体组织，其原因与奥氏体晶粒细化和奥氏体中碳浓度分布不均匀有关。
拉伸试样采用ｄ０＝１０ｍｍ、Ｌ０＝５ｄ０的短试样，硬度试块的尺寸为 !１８ｍｍ×２０ｍｍ。每个温度点处理的拉伸试样和硬度试块各３个，取其平均值作为试验结果。
２实验结果
各试样的淬火工艺及其力学性能见表１。
３６
《热加工工艺》２００７年第３６卷第６期
２５ＭｎＶ是矿用圆环链专用钢，工作时承受较大的拉应力，同时存在一定的磨粒磨损和冲击载荷，要求经淬火、回火处理后得到低碳马氏体组织，具有良好的强韧性。弄清“零保温”淬火状态下该钢的组织与力学性能，对推广圆环链“零保温” 淬火技术、提高圆环链质量、降低制造成本具有实
收稿日期：２００６－１０－３０基金项目：河南省自然科学基金资助项目（０５１１０５２６００）作者简介：李安铭（１９５５－），男，河南温县人，教授，从事金属材料及相

特征更新的动态图卷积表面损伤点云分割方法

第41卷　第4期吉林大学学报(信息科学版)Vol.41　No.42023年7月Journal of Jilin University (Information Science Edition)July 2023文章编号:1671⁃5896(2023)04⁃0621⁃10特征更新的动态图卷积表面损伤点云分割方法收稿日期:2022⁃09⁃21基金项目:国家自然科学基金资助项目(61573185)作者简介:张闻锐(1998 ),男,江苏扬州人,南京航空航天大学硕士研究生,主要从事点云分割研究,(Tel)86⁃188****8397(E⁃mail)839357306@;王从庆(1960 ),男,南京人,南京航空航天大学教授,博士生导师,主要从事模式识别与智能系统研究,(Tel)86⁃130****6390(E⁃mail)cqwang@㊂张闻锐,王从庆(南京航空航天大学自动化学院,南京210016)摘要:针对金属部件表面损伤点云数据对分割网络局部特征分析能力要求高,局部特征分析能力较弱的传统算法对某些数据集无法达到理想的分割效果问题,选择采用相对损伤体积等特征进行损伤分类,将金属表面损伤分为6类,提出一种包含空间尺度区域信息的三维图注意力特征提取方法㊂将得到的空间尺度区域特征用于特征更新网络模块的设计,基于特征更新模块构建出了一种特征更新的动态图卷积网络(Feature Adaptive Shifting⁃Dynamic Graph Convolutional Neural Networks)用于点云语义分割㊂实验结果表明,该方法有助于更有效地进行点云分割,并提取点云局部特征㊂在金属表面损伤分割上,该方法的精度优于PointNet ++㊁DGCNN(Dynamic Graph Convolutional Neural Networks)等方法,提高了分割结果的精度与有效性㊂关键词:点云分割;动态图卷积;特征更新;损伤分类中图分类号:TP391.41文献标志码:A Cloud Segmentation Method of Surface Damage Point Based on Feature Adaptive Shifting⁃DGCNNZHANG Wenrui,WANG Congqing(School of Automation,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)Abstract :The cloud data of metal part surface damage point requires high local feature analysis ability of the segmentation network,and the traditional algorithm with weak local feature analysis ability can not achieve the ideal segmentation effect for the data set.The relative damage volume and other features are selected to classify the metal surface damage,and the damage is divided into six categories.This paper proposes a method to extract the attention feature of 3D map containing spatial scale area information.The obtained spatial scale area feature is used in the design of feature update network module.Based on the feature update module,a feature updated dynamic graph convolution network is constructed for point cloud semantic segmentation.The experimental results show that the proposed method is helpful for more effective point cloud segmentation to extract the local features of point cloud.In metal surface damage segmentation,the accuracy of this method is better than pointnet++,DGCNN(Dynamic Graph Convolutional Neural Networks)and other methods,which improves the accuracy and effectiveness of segmentation results.Key words :point cloud segmentation;dynamic graph convolution;feature adaptive shifting;damage classification 0　引　言基于深度学习的图像分割技术在人脸㊁车牌识别和卫星图像分析领域已经趋近成熟,为获取物体更226吉林大学学报(信息科学版)第41卷完整的三维信息,就需要利用三维点云数据进一步完善语义分割㊂三维点云数据具有稀疏性和无序性,其独特的几何特征分布和三维属性使点云语义分割在许多领域的应用都遇到困难㊂如在机器人与计算机视觉领域使用三维点云进行目标检测与跟踪以及重建;在建筑学上使用点云提取与识别建筑物和土地三维几何信息;在自动驾驶方面提供路面交通对象㊁道路㊁地图的采集㊁检测和分割功能㊂2017年,Lawin等[1]将点云投影到多个视图上分割再返回点云,在原始点云上对投影分割结果进行分析,实现对点云的分割㊂最早的体素深度学习网络产生于2015年,由Maturana等[2]创建的VOXNET (Voxel Partition Network)网络结构,建立在三维点云的体素表示(Volumetric Representation)上,从三维体素形状中学习点的分布㊂结合Le等[3]提出的点云网格化表示,出现了类似PointGrid的新型深度网络,集成了点与网格的混合高效化网络,但体素化的点云面对大量点数的点云文件时表现不佳㊂在不规则的点云向规则的投影和体素等过渡态转换过程中,会出现很多空间信息损失㊂为将点云自身的数据特征发挥完善,直接输入点云的基础网络模型被逐渐提出㊂2017年,Qi等[4]利用点云文件的特性,开发了直接针对原始点云进行特征学习的PointNet网络㊂随后Qi等[5]又提出了PointNet++,针对PointNet在表示点与点直接的关联性上做出改进㊂Hu等[6]提出SENET(Squeeze⁃and⁃Excitation Networks)通过校准通道响应,为三维点云深度学习引入通道注意力网络㊂2018年,Li等[7]提出了PointCNN,设计了一种X⁃Conv模块,在不显著增加参数数量的情况下耦合较远距离信息㊂图卷积网络[8](Graph Convolutional Network)是依靠图之间的节点进行信息传递,获得图之间的信息关联的深度神经网络㊂图可以视为顶点和边的集合,使每个点都成为顶点,消耗的运算量是无法估量的,需要采用K临近点计算方式[9]产生的边缘卷积层(EdgeConv)㊂利用中心点与其邻域点作为边特征,提取边特征㊂图卷积网络作为一种点云深度学习的新框架弥补了Pointnet等网络的部分缺陷[10]㊂针对非规律的表面损伤这种特征缺失类点云分割,人们已经利用各种二维图像采集数据与卷积神经网络对风扇叶片㊁建筑和交通工具等进行损伤检测[11],损伤主要类别是裂痕㊁表面漆脱落等㊂但二维图像分割涉及的损伤种类不够充分,可能受物体表面污染㊁光线等因素影响,将凹陷㊁凸起等损伤忽视,或因光照不均匀判断为脱漆㊂笔者提出一种基于特征更新的动态图卷积网络,主要针对三维点云分割,设计了一种新型的特征更新模块㊂利用三维点云独特的空间结构特征,对传统K邻域内权重相近的邻域点采用空间尺度进行区分,并应用于对金属部件表面损伤分割的有用与无用信息混杂的问题研究㊂对邻域点进行空间尺度划分,将注意力权重分组,组内进行特征更新㊂在有效鉴别外邻域干扰特征造成的误差前提下,增大特征提取面以提高局部区域特征有用性㊂1　深度卷积网络计算方法1.1　包含空间尺度区域信息的三维图注意力特征提取方法由迭代最远点采集算法将整片点云分割为n个点集:{M1,M2,M3, ,M n},每个点集包含k个点:{P1, P2,P3, ,P k},根据点集内的空间尺度关系,将局部区域划分为不同的空间区域㊂在每个区域内,结合局部特征与空间尺度特征,进一步获得更有区分度的特征信息㊂根据注意力机制,为K邻域内的点分配不同的权重信息,特征信息包括空间区域内点的分布和区域特性㊂将这些特征信息加权计算,得到点集的卷积结果㊂使用空间尺度区域信息的三维图注意力特征提取方式,需要设定合适的K邻域参数K和空间划分层数R㊂如果K太小,则会导致弱分割,因不能完全利用局部特征而影响结果准确性;如果K太大,会增加计算时间与数据量㊂图1为缺损损伤在不同参数K下的分割结果图㊂由图1可知,在K=30或50时,分割结果效果较好,K=30时计算量较小㊂笔者选择K=30作为实验参数㊂在分析确定空间划分层数R之前,简要分析空间层数划分所应对的问题㊂三维点云所具有的稀疏性㊁无序性以及损伤点云自身噪声和边角点多的特性,导致了点云处理中可能出现的共同缺点,即将离群值点云选为邻域内采样点㊂由于损伤表面多为一个面,被分割出的损伤点云应在该面上分布,而噪声点则被分布在整个面的两侧,甚至有部分位于损伤内部㊂由于点云噪声这种立体分布的特征,导致了离群值被选入邻域内作为采样点存在㊂根据采用DGCNN(Dynamic Graph Convolutional Neural Networks)分割网络抽样实验结果,位于切面附近以及损伤内部的离群值点对点云分割结果造成的影响最大,被错误分割为特征点的几率最大,在后续预处理过程中需要对这种噪声点进行优先处理㊂图1　缺损损伤在不同参数K 下的分割结果图Fig.1　Segmentation results of defect damage under different parameters K 基于上述实验结果,在参数K =30情况下,选择空间划分层数R ㊂缺损损伤在不同参数R 下的分割结果如图2所示㊂图2b 的结果与测试集标签分割结果更为相似,更能体现损伤的特征,同时屏蔽了大部分噪声㊂因此,选择R =4作为实验参数㊂图2　缺损损伤在不同参数R 下的分割结果图Fig.2　Segmentation results of defect damage under different parameters R 在一个K 邻域内,邻域点与中心点的空间关系和特征差异最能表现邻域点的权重㊂空间特征系数表示邻域点对中心点所在点集的重要性㊂同时,为更好区分图内邻域点的权重,需要将整个邻域细分㊂以空间尺度进行细分是较为合适的分类方式㊂中心点的K 邻域可视为一个局部空间,将其划分为r 个不同的尺度区域㊂再运算空间注意力机制,为这r 个不同区域的权重系数赋值㊂按照空间尺度多层次划分,不仅没有损失核心的邻域点特征,还能有效抑制无意义的㊁有干扰性的特征㊂从而提高了深度学习网络对点云的局部空间特征的学习能力,降低相邻邻域之间的互相影响㊂空间注意力机制如图3所示,计算步骤如下㊂第1步,计算特征系数e mk ㊂该值表示每个中心点m 的第k 个邻域点对其中心点的权重㊂分别用Δp mk 和Δf mk 表示三维空间关系和局部特征差异,M 表示MLP(Multi⁃Layer Perceptrons)操作,C 表示concat 函数,其中Δp mk =p mk -p m ,Δf mk =M (f mk )-M (f m )㊂将两者合并后输入多层感知机进行计算,得到计算特征系数326第4期张闻锐,等:特征更新的动态图卷积表面损伤点云分割方法图3　空间尺度区域信息注意力特征提取方法示意图Fig.3　Schematic diagram of attention feature extraction method for spatial scale regional information e mk =M [C (Δp mk ‖Δf mk )]㊂(1) 第2步,计算图权重系数a mk ㊂该值表示每个中心点m 的第k 个邻域点对其中心点的权重包含比㊂其中k ∈{1,2,3, ,K },K 表示每个邻域所包含点数㊂需要对特征系数e mk 进行归一化,使用归一化指数函数S (Softmax)得到权重多分类的结果,即计算图权重系数a mk =S (e mk )=exp(e mk )/∑K g =1exp(e mg )㊂(2) 第3步,用空间尺度区域特征s mr 表示中心点m 的第r 个空间尺度区域的特征㊂其中k r ∈{1,2,3, ,K r },K r 表示第r 个空间尺度区域所包含的邻域点数,并在其中加入特征偏置项b r ,避免权重化计算的特征在动态图中累计单面误差指向,空间尺度区域特征s mr =∑K r k r =1[a mk r M (f mk r )]+b r ㊂(3) 在r 个空间尺度区域上进行计算,就可得到点m 在整个局部区域的全部空间尺度区域特征s m ={s m 1,s m 2,s m 3, ,s mr },其中r ∈{1,2,3, ,R }㊂1.2　基于特征更新的动态图卷积网络动态图卷积网络是一种能直接处理原始三维点云数据输入的深度学习网络㊂其特点是将PointNet 网络中的复合特征转换模块(Feature Transform),改进为由K 邻近点计算(K ⁃Near Neighbor)和多层感知机构成的边缘卷积层[12]㊂边缘卷积层功能强大,其提取的特征不仅包含全局特征,还拥有由中心点与邻域点的空间位置关系构成的局部特征㊂在动态图卷积网络中,每个邻域都视为一个点集㊂增强对其中心点的特征学习能力,就会增强网络整体的效果[13]㊂对一个邻域点集,对中心点贡献最小的有效局部特征的边缘点,可以视为异常噪声点或低权重点,可能会给整体分割带来边缘溢出㊂点云相比二维图像是一种信息稀疏并且噪声含量更大的载体㊂处理一个局域内的噪声点,将其直接剔除或简单采纳会降低特征提取效果,笔者对其进行低权重划分,并进行区域内特征更新,增强抗噪性能,也避免点云信息丢失㊂在空间尺度区域中,在区域T 内有s 个点x 被归为低权重系数组,该点集的空间信息集为P ∈R N s ×3㊂点集的局部特征集为F ∈R N s ×D f [14],其中D f 表示特征的维度空间,N s 表示s 个域内点的集合㊂设p i 以及f i 为点x i 的空间信息和特征信息㊂在点集内,对点x i 进行小范围内的N 邻域搜索,搜索其邻域点㊂则点x i 的邻域点{x i ,1,x i ,2, ,x i ,N }∈N (x i ),其特征集合为{f i ,1,f i ,2, ,f i ,N }∈F ㊂在利用空间尺度进行区域划分后,对空间尺度区域特征s mt 较低的区域进行区域内特征更新,通过聚合函数对权重最低的邻域点在图中的局部特征进行改写㊂已知中心点m ,点x i 的特征f mx i 和空间尺度区域特征s mt ,目的是求出f ′mx i ,即中心点m 的低权重邻域点x i 在进行邻域特征更新后得到的新特征㊂对区域T 内的点x i ,∀x i ,j ∈H (x i ),x i 与其邻域H 内的邻域点的特征相似性域为R (x i ,x i ,j )=S [C (f i ,j )T C (f i ,j )/D o ],(4)其中C 表示由输入至输出维度的一维卷积,D o 表示输出维度值,T 表示转置㊂从而获得更新后的x i 的426吉林大学学报(信息科学版)第41卷特征㊂对R (x i ,x i ,j )进行聚合,并将特征f mx i 维度变换为输出维度f ′mx i =∑[R (x i ,x i ,j )S (s mt f mx i )]㊂(5) 图4为特征更新网络模块示意图,展示了上述特征更新的计算过程㊂图5为特征更新的动态图卷积网络示意图㊂图4　特征更新网络模块示意图Fig.4　Schematic diagram of feature update network module 图5　特征更新的动态图卷积网络示意图Fig.5　Flow chart of dynamic graph convolution network with feature update 动态图卷积网络(DGCNN)利用自创的边缘卷积层模块,逐层进行边卷积[15]㊂其前一层的输出都会动态地产生新的特征空间和局部区域,新一层从前一层学习特征(见图5)㊂在每层的边卷积模块中,笔者在边卷积和池化后加入了空间尺度区域注意力特征,捕捉特定空间区域T 内的邻域点,用于特征更新㊂特征更新会降低局域异常值点对局部特征的污染㊂网络相比传统图卷积神经网络能获得更多的特征信息,并且在面对拥有较多噪声值的点云数据时,具有更好的抗干扰性[16],在对性质不稳定㊁不平滑并含有需采集分割的突出中心的点云数据时,会有更好的抗干扰效果㊂相比于传统预处理方式,其稳定性更强,不会发生将突出部分误分割或漏分割的现象[17]㊂2　实验结果与分析点云分割的精度评估指标主要由两组数据构成[18],即平均交并比和总体准确率㊂平均交并比U (MIoU:Mean Intersection over Union)代表真实值和预测值合集的交并化率的平均值,其计算式为526第4期张闻锐,等:特征更新的动态图卷积表面损伤点云分割方法U =1T +1∑Ta =0p aa ∑Tb =0p ab +∑T b =0p ba -p aa ,(6)其中T 表示类别,a 表示真实值,b 表示预测值,p ab 表示将a 预测为b ㊂总体准确率A (OA:Overall Accuracy)表示所有正确预测点p c 占点云模型总体数量p all 的比,其计算式为A =P c /P all ,(7)其中U 与A 数值越大,表明点云分割网络越精准,且有U ≤A ㊂2.1　实验准备与数据预处理实验使用Kinect V2,采用Depth Basics⁃WPF 模块拍摄金属部件损伤表面获得深度图,将获得的深度图进行SDK(Software Development Kit)转化,得到pcd 格式的点云数据㊂Kinect V2采集的深度图像分辨率固定为512×424像素,为获得更清晰的数据图像,需尽可能近地采集数据㊂选择0.6~1.2m 作为采集距离范围,从0.6m 开始每次增加0.2m,获得多组采量数据㊂点云中分布着噪声,如果不对点云数据进行过滤会对后续处理产生不利影响㊂根据统计原理对点云中每个点的邻域进行分析,再建立一个特别设立的标准差㊂然后将实际点云的分布与假设的高斯分布进行对比,实际点云中误差超出了标准差的点即被认为是噪声点[19]㊂由于点云数据量庞大,为提高效率,选择采用如下改进方法㊂计算点云中每个点与其首个邻域点的空间距离L 1和与其第k 个邻域点的空间距离L k ㊂比较每个点之间L 1与L k 的差,将其中差值最大的1/K 视为可能噪声点[20]㊂计算可能噪声点到其K 个邻域点的平均值,平均值高出标准差的被视为噪声点,将离群噪声点剔除后完成对点云的滤波㊂2.2　金属表面损伤点云关键信息提取分割方法对点云损伤分割,在制作点云数据训练集时,如果只是单一地将所有损伤进行统一标记,不仅不方便进行结果分析和应用,而且也会降低特征分割的效果㊂为方便分析和控制分割效果,需要使用ArcGIS 将点云模型转化为不规则三角网TIN(Triangulated Irregular Network)㊂为精确地分类损伤,利用图6　不规则三角网模型示意图Fig.6　Schematic diagram of triangulated irregular networkTIN 的表面轮廓性质,获得训练数据损伤点云的损伤内(外)体积,损伤表面轮廓面积等㊂如图6所示㊂选择损伤体积指标分为相对损伤体积V (RDV:Relative Damege Volume)和邻域内相对损伤体积比N (NRDVR:Neighborhood Relative Damege Volume Ratio)㊂计算相对平均深度平面与点云深度网格化平面之间的部分,得出相对损伤体积㊂利用TIN 邻域网格可获取某损伤在邻域内的相对深度占比,有效解决制作测试集时,将因弧度或是形状造成的相对深度判断为损伤的问题㊂两种指标如下:V =∑P d k =1h k /P d -∑P k =1h k /()P S d ,(8)N =P n ∑P d k =1h k S d /P d ∑P n k =1h k S ()n -()1×100%,(9)其中P 表示所有点云数,P d 表示所有被标记为损伤的点云数,P n 表示所有被认定为损伤邻域内的点云数;h k 表示点k 的深度值;S d 表示损伤平面面积,S n 表示损伤邻域平面面积㊂在获取TIN 标准包络网视图后,可以更加清晰地描绘损伤情况,同时有助于量化损伤严重程度㊂笔者将损伤分为6种类型,并利用计算得出的TIN 指标进行损伤分类㊂同时,根据损伤部分体积与非损伤部分体积的关系,制定指标损伤体积(SDV:Standard Damege Volume)区分损伤类别㊂随机抽选5个测试组共50张图作为样本㊂统计非穿透损伤的RDV 绝对值,其中最大的30%标记为凹陷或凸起,其余626吉林大学学报(信息科学版)第41卷标记为表面损伤,并将样本分类的标准分界值设为SDV㊂在设立以上标准后,对凹陷㊁凸起㊁穿孔㊁表面损伤㊁破损和缺损6种金属表面损伤进行分类,金属表面损伤示意图如图7所示㊂首先,根据损伤是否产生洞穿,将损伤分为两大类㊂非贯通伤包括凹陷㊁凸起和表面损伤,贯通伤包括穿孔㊁破损和缺损㊂在非贯通伤中,凹陷和凸起分别采用相反数的SDV 作为标准,在这之间的被分类为表面损伤㊂贯通伤中,以损伤部分平面面积作为参照,较小的分类为穿孔,较大的分类为破损,而在边缘处因腐蚀㊁碰撞等原因缺角㊁内损的分类为缺损㊂分类参照如表1所示㊂图7　金属表面损伤示意图Fig.7　Schematic diagram of metal surface damage表1　损伤类别分类Tab.1　Damage classification 损伤类别凹陷凸起穿孔表面损伤破损缺损是否形成洞穿××√×√√RDV 绝对值是否达到SDV √√\×\\S d 是否达到标准\\×\√\2.3　实验结果分析为验证改进的图卷积深度神经网络在点云语义分割上的有效性,笔者采用TensorFlow 神经网络框架进行模型测试㊂为验证深度网络对损伤分割的识别准确率,采集了带有损伤特征的金属部件损伤表面点云,对点云进行预处理㊂对若干金属部件上的多个样本金属面的点云数据进行筛选,删除损伤占比低于5%或高于60%的数据后,划分并装包制作为点云数据集㊂采用CloudCompare 软件对样本金属上的损伤部分进行分类标记,共分为6种如上所述损伤㊂部件损伤的数据集制作参考点云深度学习领域广泛应用的公开数据集ModelNet40part㊂分割数据集包含了多种类型的金属部件损伤数据,这些损伤数据显示在510张总点云图像数据中㊂点云图像种类丰富,由各种包含损伤的金属表面构成,例如金属门,金属蒙皮,机械构件外表面等㊂用ArcGIS 内相关工具将总图进行随机点拆分,根据数据集ModelNet40part 的规格,每个独立的点云数据组含有1024个点,将所有总图拆分为510×128个单元点云㊂将样本分为400个训练集与110个测试集,采用交叉验证方法以保证测试的充分性[20],对多种方法进行评估测试,实验结果由单元点云按原点位置重新组合而成,并带有拆分后对单元点云进行的分割标记㊂分割结果比较如图8所示㊂726第4期张闻锐,等:特征更新的动态图卷积表面损伤点云分割方法图8　分割结果比较图Fig.8　Comparison of segmentation results在部件损伤分割的实验中,将不同网络与笔者网络(FAS⁃DGCNN:Feature Adaptive Shifting⁃Dynamic Graph Convolutional Neural Networks)进行对比㊂除了采用不同的分割网络外,其余实验均采用与改进的图卷积深度神经网络方法相同的实验设置㊂实验结果由单一损伤交并比(IoU:Intersection over Union),平均损伤交并比(MIoU),单一损伤准确率(Accuracy)和总体损伤准确率(OA)进行评价,结果如表2~表4所示㊂将6种不同损伤类别的Accuracy 与IoU 进行对比分析,可得出结论:相比于基准实验网络Pointet++,笔者在OA 和MioU 方面分别在贯通伤和非贯通伤上有10%和20%左右的提升,在整体分割指标上,OA 能达到90.8%㊂对拥有更多点数支撑,含有较多点云特征的非贯通伤,几种点云分割网络整体性能均能达到90%左右的效果㊂而不具有局部特征识别能力的PointNet 在贯通伤上的表现较差,不具备有效的分辨能力,导致分割效果相对于其他损伤较差㊂表2　损伤部件分割准确率性能对比 Tab.2　Performance comparison of segmentation accuracy of damaged parts %实验方法准确率凹陷⁃1凸起⁃2穿孔⁃3表面损伤⁃4破损⁃5缺损⁃6Ponitnet 82.785.073.880.971.670.1Pointnet++88.786.982.783.486.382.9DGCNN 90.488.891.788.788.687.1FAS⁃DGCNN 92.588.892.191.490.188.6826吉林大学学报(信息科学版)第41卷表3　损伤部件分割交并比性能对比 Tab.3　Performance comparison of segmentation intersection ratio of damaged parts %IoU 准确率凹陷⁃1凸起⁃2穿孔⁃3表面损伤⁃4破损⁃5缺损⁃6PonitNet80.582.770.876.667.366.9PointNet++86.384.580.481.184.280.9DGCNN 88.786.589.986.486.284.7FAS⁃DGCNN89.986.590.388.187.385.7表4　损伤分割的整体性能对比分析　　出,动态卷积图特征以及有效的邻域特征更新与多尺度注意力给分割网络带来了更优秀的局部邻域分割能力,更加适应表面损伤分割的任务要求㊂3　结　语笔者利用三维点云独特的空间结构特征,将传统K 邻域内权重相近的邻域点采用空间尺度进行区分,并将空间尺度划分运用于邻域内权重分配上,提出了一种能将邻域内噪声点降权筛除的特征更新模块㊂采用此模块的动态图卷积网络在分割上表现出色㊂利用特征更新的动态图卷积网络(FAS⁃DGCNN)能有效实现金属表面损伤的分割㊂与其他网络相比,笔者方法在点云语义分割方面表现出更高的可靠性,可见在包含空间尺度区域信息的注意力和局域点云特征更新下,笔者提出的基于特征更新的动态图卷积网络能发挥更优秀的作用,而且相比缺乏局部特征提取能力的分割网络,其对于点云稀疏㊁特征不明显的非贯通伤有更优的效果㊂参考文献:[1]LAWIN F J,DANELLJAN M,TOSTEBERG P,et al.Deep Projective 3D Semantic Segmentation [C]∥InternationalConference on Computer Analysis of Images and Patterns.Ystad,Sweden:Springer,2017:95⁃107.[2]MATURANA D,SCHERER S.VoxNet:A 3D Convolutional Neural Network for Real⁃Time Object Recognition [C]∥Proceedings of IEEE /RSJ International Conference on Intelligent Robots and Systems.Hamburg,Germany:IEEE,2015:922⁃928.[3]LE T,DUAN Y.PointGrid:A Deep Network for 3D Shape Understanding [C]∥2018IEEE /CVF Conference on ComputerVision and Pattern Recognition (CVPR).Salt Lake City,USA:IEEE,2018:9204⁃9214.[4]QI C R,SU H,MO K,et al.PointNet:Deep Learning on Point Sets for 3D Classification and Segmentation [C]∥IEEEConference on Computer Vision 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Metal-insulator transition in 2D resistance in the critical region

a r X i v :c o n d -m a t /0003032v 2 [c o n d -m a t .m e s -h a l l ] 20 A p r 2000Metal-insulator transition in 2D:resistance in the critical regionB.L.Altshuler 1,2,D.L.Maslov,3and V.M.Pudalov 41)NEC Research Institute,4Independence Way,Princeton,NJ 085402)Physics Department,Princeton University,Princeton,NJ 085443)Department of Physics,University of Florida P.O.Box 118440,Gainesville,Florida 32611-84404)P.N.Lebedev Physics Institute,Russian Academy of SciencesLeninsky Prospect 53,Moscow 117924,Russia(February 1,2008)The goal of this paper is to highlight several issues which are most crucial for the understanding of the “metal-insulator transition”in two dimensions.We discuss some common problems in in-terpreting experimental results on high mobility Si MOSFETs.We analyze concepts and methods used to determine the critical density of electrons at the metal-insulator transition.In particular,we discuss the origin of the temperature dependence of the resistivity and reasons for this dependence to ﬂatten out at some electron density in the vicinity of the metal-insulator transition.This ﬂattening has recently been proposed to indicate a true quantum phase transition.We suggest an alternative interpretation of this result and demonstrate the consistency of our proposition with the experimen-tal data.One of the main questions,which arise in connection with the transition,is whether or not the metallic state is qualitatively distinct from a conventional disordered Fermi liquid.We analyze the arguments in favor of both aﬃrmative and negative answers to this question and conclude that the experimental results accumulated up-to-date do not provide convincing evidence for the new state of matter characterized by a metallic-like residual conductivity.We also discuss in details the measurement and control of the electron temperature;these issues are crucial for interpreting the low-temperature experimental data.PACS numbers:71.30.+h,72.15Rn,73.40.QvI.INTRODUCTIONAfter several years of intensive experimental and the-oretical eﬀorts(see,e.g.,Ref.[1]for an extensive bib-liography),even the basic features of the phenomenon known as the“metal-insulator transition in two dimen-sions”(2D MIT)remain to be the subjects of ongoing discussions.Is this phenomenon a true“quantum phase transition”(QPT)[2]or can it be understood in terms of conventional physics of disordered conductors[3,4]? This question is at the heart of the whole discussion. Recently,we wrote a paper[5]in favor of the second possibility.In particular,we argued thati)in the“metallic phase”,2D systems seem to behaveas a quite conventional disordered metal ratherthan a distinctly new state of matter and ii)it is possible to explain the anomalous behavior of the resistivity,ρ(T),by an interplay of two temper-ature dependences:the one given by a metallic-like,quasiclassical(Drude)resistivity[6],ρd(T),andthe other one arising from quantum localization. We do realize that ii)represents a rather naive ap-proach,at least because it does not fully take into account the Coulomb interaction between electrons,whereas the most pronounced eﬀects have been observed in systems with a priori strong electron-electron correlations.Nev-ertheless,this approach allows one to describe qualita-tively,and even semi-quantitatively,most of the results on electron transport both in metallic phase and near the transition point.This suggests that it is a good starting point for developing an adequate theoretical understand-ing of the MIT in two dimensions.Conclusion i)is based on the analysis of existing ex-perimental data,as summarized in Refs.[5,7].It has been further supported by recent experimental papers[ 1,8–10],which showed that the transport properties of Si/Ge,Si MOSFET and p-GaAs structures in the metal-lic regime can be successfully interpreted in conventional terms.Authors of Refs.[9,10]have also identiﬁed the contribution of electron-electron interactions to the resis-tance(via measuring the temperature-dependent part of the Hall resistance)and found that it remains quite small even when parameter r s is rather large.There is also a number of recent theoretical papers[11–14,7]which, although diﬀering in a particular mechanism for the T-dependence of the Drude resistivity,share the general spirit of propositions i)and ii).An alternative point of view,expressed,for example, in Refs.[15–17],is that the observed MIT-like behavior indicates a true quantum phase transition between an insulator and a novel metallic phase.Motivated by the importance of this controversy,i.e.,QPT versus proposi-tions i)and ii),for theﬁeld of quantum transport in2D and its possible relevance for other realizations of quan-tum phase transitions,we decided to analyze in detail the arguments on both sides of the QPT question.In this paper,we discuss recent and some of the previously pub-lished experimental results on the resistivity of Si MOS-FETs in the vicinity of the MIT,along with some of the theoretical interpretations of these results.We conclude that that there is no convincing experimental evidence for the QPT in the existing data.As one of the main questions in theﬁeld is the behavior of a2D system in the limit T→0,we begin our analysis with a short summary of recent results by Kravchenko and Klapwijk(KK)[15],who measured the temperature dependence of the resistivity down to a bath temperature as low as T bath=35mK.This paper reports measure-ments on a single Si MOSFET sample with peak mobil-ityµpeak=27,000cm2/Vs in the range from35mK to 1.2K atﬁve diﬀerent electron concentrations.Digitized data from Ref.[15]is shown in Fig.1(curves1-5).In Ref.[15],the following two points are emphasized:1)For n=n1=6.85×1010cm−2and n=n2=7.17×1010cm−2(curves1and2),the resistivitydecreases as temperature increases(dρ/dT<0);for n=n4=7.57×1010cm−2and n=n5=7.85×1010cm−2(curves4and5),the resistivity increaseswith temperature(dρ/dT>0).Based on these ob-servations,the authors argue that curves1and2correspond to an insulating phase,whereas curves4and5demonstrate a metallic behavior.At n=n3=7.25×1010cm−2(curve3),only a weak(±5%)temperature dependence was observed within theinterval of bath temperature from35mK to1K.The authors conclude that n3=7.25×1010cm−2isthe critical electron density for their sample,i.e.,itcorresponds to the metal-insulator transition point.Note that this conclusion is based entirely on thetemperature independence of curve3over a rela-tively narrow temperature range.2)Another observation,emphasized in Ref.[15],isthat in the range0.1K<T<0.4K the metal-licρ(T)-dependences(curves4,5)appear to benearly linear and thus diﬀerent from the exponen-tial temperature dependence observed in other ex-periments.KK stress that in this region the re-sistivity shows no insulating up-turn at the lowesttemperature achieved.KK consider the fact that they observed no tempera-ture dependence of the resistivity of their sample at a cer-tain concentration n=n3as a strong argument against our model[5].They point out that such a precise cancel-lation would require a special relation betweenρd(T)and the scalingβ(ρ)-function.KK argue that this relation be-tween two objects of entirely diﬀerent origin“would be a remarkable coincidence”,and is therefore unlikely. Based on the arguments listed above,authors of Ref.[15]conclude that their experiments are consistent with the existence of the zero-temperature quantum phase transition.r K HUÃ FÃFIG.1.Resistivity vs temperature,reproduced from Fig.2of Ref.[15].Electron density n in units of 1010cm −2:1- 6.85,2-7.17,3-7.25,4-7.57,5-7.85.Dashed curves A 1and A 2:ﬁts of data 1and 2by 2.29exp (403/T )1/2 and2.84exp (11.11/T )1/2,respectively (T is in mK).Solid curves B 1and B 2:ﬁts of the same data by 1.25exp (1685/T )1/3 and 2.55exp (8./T )1/3 ,re-spectively.Semi-open symbols (1′′):reﬂection of data points 1about curve 3.Curves E and F :best ﬁts of data 4and 5by ρ4(T )=1.2+1.45exp(−450/T )and ρ5(T )=0.63+1.6exp(−485/T ),respectively.Note that a rather narrow range of densities was ex-plored in Ref.[15].To show the development of the MIT-phenomenon over a wider range of densities and temper-atures,we present in Fig.2the results of Ref.[18]for a sample with a close value of µpeak .The encircled region of the {T,n }plane (region KK in this ﬁgure)indicates roughly the domain of parameters explored in Ref.[15].The temperature in Fig.2is normalized to the Fermi en-ergy E F ,in order to demonstrate that resistivities corre-sponding to quite diﬀerent Fermi energies,and therefore r s -values,exhibit similar T -dependences.A strong (50-100%)drop in ρis still present for n <∼20×1011cm −2,which corresponds to r s ∼2and ρ∼0.01h/e 2.Thus,contrary to the popular opinion,the resistance drop is not intrinsic only to the low density range (high r -values).r K H7 ()FIG.2.Resistivity vs temperature (from 0.3to ≈40K)for a wide range of densities and Fermi energies.The ﬁgure is reproduced from Ref.[18].Encircled region:domain of parameters explored in Ref.[15].Dash-dotted vertical line depicts the em-pirical temperature,T Q =0.007E F ,below which the logarithmic temperature dependence sets in.We would like to stress once again that in the region of high densities and small resistivities quantum inter-ference corrections of any kind (weak localization,ex-change and Hartree interactions,spin-orbit,etc.)would amount only to a few percent variation (of both signs)in ρwith T .The phonon contribution to the resistiv-ity of Si-MOSFETs can be shown to be negligible atleast for n <∼20×1011cm−2in the relevant T -range.Therefore,there must be some other mechanism of the T -dependence at work,neither of quantum interference nor of phonon nature.The resistance drop of non-phonon nature persists up to the highest temperature of these measurements,which is ≈35−40K for each curve in Fig.2(for conversion of densities into the Fermi-energies,use the formula:E F [K]=7.31×n [1011cm −2]).II.METAL,INSULATOR,AND CRITICAL POINT.GENERAL DISCUSSION Contrary to a common belief,a metallic phase and thus a metal-insulator transition can in principle occur in two dimensions.For example,in a hypothetical situ-ation of non-interacting electrons spin-orbit coupling re-sults in resistivity vanishing with temperature,provided that disorder is suﬃciently weak(“weak antilocalization”[3,4,19]).However,if disorder is strong enough,it leads to localization.The metallic state is stable with respect to weak and short-ranged electron-electron interactions. The Coulomb interaction between electrons for small r s overwhelms weak antilocalization and thus destroys the metallic state with zero residual resistivity.Nevertheless, the Coulomb interaction itself brings in an antilocalizing contribution to the resistivity(triplet channel).For small r s,this contribution is smaller than the one from the sin-glet channel,and thus the net eﬀect of interactions is the enhancement of localization.It may be the case that the triplet channel wins for larger r s and a metallic state be-comes possible.(In fact,this scenario follows from the RG treatment[20–22].)However,if such a state exists,it must be distinct from the conventional“disordered Fermi liquid”.So far,the experimental evidence is in contrast with the existence of a distinctly new state(see Refs.[5,7]). In fact,at higher densities the resistivity exhibits an in-sulating up-turn in agreement with the weak localization theory.We believe that in the existing experiments the true low-temperature asymptotic behavior has not yet been achieved for lower densities(in the vicinity of the transition).Therefore,one cannot interpret the crossover between dρ/dT>0and dρ/dT<0atﬁnite tempera-tures as a proof for the existence of two distinct phases. Nevertheless,it is instructive to adopt such an interpre-tation for a moment and to compare the experimentally observedρ(T)with the commonly accepted picture of a quantum phase transition.Let usﬁrst recall what is known about the transition in3D.We start our analysis by formulating the deﬁnitions of metal and insulator.Arguing about deﬁnitions is not a too rational thing to do–a deﬁnition cannot be right or wrong.We simply point out that for the well-studied case of MIT in3D,the commonly held deﬁnitions of both phases diﬀer from those adopted by KK.In3D systems,ρinsulator(T→0)→∞,whereasρmetal(T→0)isﬁnite (see[3,4,22]and references therein).In fact,dρ/dT is negative in both the metallic and insulating phases,pro-vided that the system is close to the transition point and the temperature is low enough.For non-interacting particles,the conventional sce-nario of the3D MIT is well supported by the pertur-bation theory and renormalization group arguments[ 3,4,23,22].According to this scenario,in the metallic phase close to the transitionρ(T)increases as T−αas temperature decreases.The increase ofρ(T)saturates at T<∼T sat.Upon approaching the critical point,T sat tends to zero.Therefore,exactly at the critical density theρ(T)-dependence is a power law:ρ(T)∼T−α.Inthe insulating phase,the resistivity behaves as exp(T0/T) (nearest neighbor hopping)or as exp[(T0/T)β](variablerange hopping).The exponentαis determined by mech-anisms of dephasing.As a result,it is,strictly speak-ing,non-universal.Let the dephasing rate scale with temperature as1/τϕ∝T p.Then assuming that(a) one-parameter scaling holds,(b)this parameter is the conductance,and(c)p=1,one arrives atα=1/3.Note that the electron-electron interactions can change the value ofα.Numerous experiments on3D doped semiconductors conﬁrmed the power-law behavior ofρin the critical re-gion.However,there is still no consensus regarding the value ofα:bothα=1/2[24–26]andα=1/3[27,28] have been reported.It is also possible thatαdepends on whether a semiconductor is compensated or not.(For the review of an MIT in3D see Ref.[29].)Returning to the MIT in2D,we note that the assump-tion of a temperature-independent resistivity at the crit-ical density is as doubtful as the statement thatα=1/3 in3D.Indeed,both of these points can be justiﬁed only within the one-parameter scaling.This scaling does not seem to apply universally even in the3D case.For a2D system of noninteracting electrons,this scaling predicts no metallic state at all.To get a chance to describe a metallic state,one needs to add more ingredients,e.g., electron-electron interactions,to the theory.Once we deal with a problem which is richer than localization in quenched disorder,there are no reasons to assume that the one-parameter scaling still holds(see,e.g.,Ref.[20]). Therefore,a temperature-independent critical resistivity is an assumption rather than a law of nature.As an example,consider the following density-and temperature-dependences of the resistivity(which do not follow from any of the existing theories,but do not con-tradict to any of the commonly respected general princi-ples either):ρ(n,T)=ρ0(n)+ρ1(n) T T .(1)It is natural to deﬁne the critical concentration,n c,as the concentration at which T0(n)changes sign:T0(n c)=0; for n>n c(metal),T0(n)is negative,whereas for n>n c (insulator),T0(n)is positive.It is also assumed that ρ0(n),ρ1(n)and T1(n)are smooth functions of the den-sity in the vicinity of the transition point n=n c.Ac-cording to Eq.(1),exactly at the critical point(n=n c)ρ(n c,T)=ρ0+ρ1 Tmaximum at T=−T0/α.We do not think that such a maximum is a mandatory feature of the MIT in two dimensions.)We conclude that,at least in this example, a temperature-independent resistivity is a signature of a metal rather than of a critical point.Regardless of this particular and rather artiﬁcial exam-ple,we notice that it is neither easy nor a straightforward task to determine the critical point of an MIT.Quan-tum phase transitions are zero temperature phenomena, whereas experiments are performed atﬁnite T.There-fore,to determine the critical concentration,one does not have another choice but to analyze the data taken at the lowest accessible temperatures.This analysis should prove thatρ(T)indeed acquires insulating exponential behavior as soon as the concentration gets lower than the apparent value of n c.Weﬁnd it more appropriate to use the onset of the insulating exponential behavior inρ(T)rather than the vanishing of the derivative dρ/dT for an experimental identiﬁcation of the critical point.We are not aware of any reasons to assign the meaning of the critical point to a density n∗c at which the temperature dependence of the resistivity is least pronounced,as it was done by KK.Indeed,direct measurements of the two quantities, n∗c(from the temperature independent“separatrix”)and n c(from the disappearance of the non-Ohmic hopping behavior)conﬁrm their systematic diﬀerence for high-µsamples:n∗c is larger than n c by1-5%(see,e.g.,Fig.3in Ref.[30]).A similar diﬀerence arises also from the com-parison of critical behaviors in the thermoelectric power and conductance[31].Note that four out ofﬁve electron densities in Ref.[15],n=n1−n4,fall into this ambigu-ous interval.III.EXPERIMENTAL DETERMINATION OFTHE CRITICAL POINT.We now turn to the experimental data of Ref.[15]. The authors assume that n c equals to7.25×1010cm−2 (curve3in Fig.1).According to the deﬁnition of the critical point,proposed in Sec.II,this assumption im-plies that at lower densities(n=n2=7.17×1010cm−2 and n=n1=6.85×1010cm−2),the resistivity increases exponentially as temperature decreases.It turns out that one canﬁt neitherρ(T,n=n2)norρ(T,n=n1)with a simple exponential dependence.However,ρ(T,n=n1) can be satisfactorily approximated byρexp(T,n)=ρ∗m exp[(T0m(n)/T)m](3) with either m=1/2or m=1/3(dashed line A1and solid line B1in Fig.1,respectively).The quality of theﬁt can be seen from the deviations of the experimental data from the straight line in the inset to Fig.1.Although curve2 in Fiq.1does not seem to behave exponentially,one can still try toﬁt it by function(3)in two diﬀerent ways: i)one can assume that T0m is proportional to|n−n c|.(This dependence was observed in previous studiesof the MIT in Si MOSFETs[32–34]).Then,us-ing the value of T0m for n=n1,one determines T0p for n=n2by linear extrapolation,whereasρ∗m is found byﬁtting the experimental data.The re-sults of this procedure for m=1/2are shown in Fig.1(dashed-and-dotted line C2).It is quite clear that such aﬁt does not work(the same is true for m=1/3,not shown).ii)Alternatively,one can simply make the bestﬁt of curve2by function(3)for m=1/2,1/3,treating T0m andρ∗m as independent parameters.Results of thisﬁt are depicted in Fig.1by curves A2and B2,respectively.It is customary to assume that in the vicinity of the critical point,T0m scales as |n−n c|zν.Given the values of T0m for n=n1,2, one can follow the assumption of KK that n c=n3 andﬁndzν=[ln T0m(n1)/T0m(n2)]Alternatively,one may conclude that the data of Ref.[15]do not provide evidence for a quantum phase tran-sition between two distinct states of matter,but ratherindicate a crossover between two diﬀerent types of(rela-tively)high temperature behavior.IV.RESISTIVITY OF SI MOSFETS IN THECRITICAL REGIONAs it has already been mentioned,any scenario of aquantum phase transition implies that for the densities close to the critical point n c the resistivityρ(T,n)at suﬃ-ciently high temperatures demonstrates a critical behav-ior.This means that the deviation ofρ(T,n)from theseparatrixρ(T,n c)is small for small values of the crit-ical parameter|n−n c|zν/T.Keeping this in mind,we now recall the main results of earlier experiments on the resistivity of high mobility Si MOSFETs in the criticalregion and compare them with KK’s results. Consider,for example,the resistivity of a sample with µpeak=55,000cm2/V s,reproduced from Ref.[30,37]in Fig.3.Assume for a moment that metallic and insulating behaviors can indeed be distinguished by the sign of the derivative dρ/dT,as suggested by KK.Atﬁrst glance, the application of this criterion to the region T<1K in Fig.3is rather unambiguous.Indeed,n∗c determined from the condition of T-independentρcorresponds to the dashed separatrix.The slope of the dashedline for the sample with µpeak =71,000cm 2/Vs (Fig.4a)is negative and its ab-solute value is about 10times bigger than in Fig.4b (µpeak =33,000cm 2/Vs).The reduction of the slope with µpeak persists down to relatively low mobilities un-til eventually the slope changes sign.This is seen from Fig.5a,reproduced from Ref.[37],where the authors presented cm 2/Vs.Ã7 . r K HÃr7 .FIG.5.Resistivity vs temperature for a low mobil-ity sample (Si-39).Numbers at the curve indicate thedensities in 1010cm −2.Reproduced from Ref.[37].Even for this low-mobility sample,the ρ(T )-dependence at the highest density measured (n =54.4×1011cm −2)shows no signs of saturation in the accessible temperature region (above 100mK),see Fig.5b.There is no consistent theoretical understanding of this µpeak -dependence of the slope yet.Such an understanding will probably come together with the description of the “crit-ical resistance”,which apparently changes from about 0.3e 2/h at low mobilities to several units of e 2/h at high µpeak [30,37],(see also discussion in Refs.[38,39]).On the other hand,it is natural that for the intermediatemobilities,the slope is small ,because it should vanish somewhere in the range from 5,000to 30,000cm 2/Vs.The mobility of KK’s sample is 27,000cm 2/Vs,i.e.,right in this range.Therefore one should not be too surprised by the fact that in some range of the concentrations the temperature dependence of the resistivity is rather ﬂat ,as it was observed by KK.Last but not least:a variety of the ρ(T )-dependences in the critical region indicates by itself the absence of uni-versality in observed MITs [30]and raises doubts that Si MOSFETs undergo a genuine quantum phase transition.V.“HOW COLD ARE THE ELECTRONS?”Heating of electrons by the applied source-drain ﬁeld as well as by external noise is a common problem in low-temperature transport measurements.This problem turns out to be especially serious in Si MOSFETS in the vicinity of the “metal-insulator transition”and at tem-peratures <∼100mK due to *)weak temperature depen-dence of the resistivity in this range of densities and **)weak electron-phonon coupling.As a result,the inter-pretation of resistivity measurements becomes rather am-biguous.For example,the temperature interval,in which the resistivity appears to be temperature-independent,may look to be much broader than it actually is.The goal of this section is to demonstrate the seriousness of this problem.In macroscopic Si MOSFETs,as well as in bulk Si,electrons couple to phonons only via the deformation po-tential.As this coupling is rather weak,the electron tem-perature,T e ,may exceed substantially the bath temper-ature,T bath ;it is also not easy to control T e .To provide convincing data,one has to use a “thermometer”capable of measuring T e directly.Any observable which depends on T e ,other than the (zero-magnetic-ﬁeld)resistivity it-self,can be used for this purpose.In earlier studies on high mobility Si-MOSFETs,Refs.[30,37,40–42],which reported results of the resistivity measurements down to T bath =18−25mK,the electron temperature was at-tempted to be measured viai)the amplitude of Shubnikov -de Haas (ShdH)oscilla-tions,ii)temperature dependence of the hopping resistivity,iii)linearity of I −V -characteristics,andiv)T e -dependence of the phase relaxation time.Unfortunately,results on T e in the up-to-date measure-ments of 2D MIT are neither fully consistent with each other nor convincing enough below T bath =250mK.No independent measurement of T e is reported in Ref.[15].It is only mentioned that the source-to-drain bias,U ,was less than 200µV “to ensure that the total power dissipated in the sample was less than 10−13W”.As it is not clear whether this is enough to prevent electrons from being overheated,it is worth discussing electron heating in Si MOSFETs.Electrons are driven out of the equilibrium by the ap-plied voltage and/or by external noise.Let P be the power deposited in the electron system.In the stationary state,all this power leaves the system either with elec-trons (through contacts)or with phonons.The phonon mechanism dominates at higher temperatures.If T is low enough,this mechanism can be neglected compared to electron out-diﬀusion,in which thermal conductivity of the electrons determines the heat balance.As our task is to estimate heating at T ∼100mK,we ﬁrst discuss what happens without phonons.Given the temperature increment ∆T =T e −T bath ,the power,which is carried out by electrons through the leads,can be estimated as (see Refs.[43]and also [44]for recent discussion):P =2πR,(5)where R is the resistance which diﬀers from the resistivityby the aspect ratio.To obtain a lower bound estimate of the bath temperature T h at which heating becomes strong,i.e.,∆T ≃T h ,we neglect heating due to external noise and assume that the main reason for heating is the source-to-drain bias,U .Accordingly,P =U 2/R .Ex-pressing the ratio ∆T/T bath through P via Eq.(5),we obtain∆T 2πT bath2=eU3νF LWT bath ∆Tn [K](where sis the speed of sound,and n in 1011cm −2)can be writtenas [47,48]1πΞ2m ∗k 2F a 3k F s3T bath5¯h k F s hεFaVI.TEMPERATURE-INDEPENDENTRESISTIVITYNow it is time to analyze the ﬁrst of the two main ar-guments that KK brought in favor of the “true quantum phase transition”,namely,the temperature-independent resistivity at what they believe to be the critical point.More speciﬁcally,KK claim that they observed no T -dependence (within a 10%margin)in the interval 35mK <T <1K.They analyzed the data in terms of our recent theory of Anderson localization by temperature-dependent disorder [5]and came to the conclusion that within this theory a nearly constant ρ(T )would imply a “remarkable coincidence”.We begin our discussion of this issue with summarizing brieﬂy the argument of KK.Afterwards,we present our theoretical counterarguments.The theory of Ref.[5]describes the T -dependence of the observable resistivity,ρ,in the presence of two fac-tors:i)the T -dependence of the Drude resistivity,ρd ,and ii)Anderson localization.Each of these two factors brings a T -dependence of its own and the resultant ρ(T )-dependence is described by the following scaling equation1d ln T =pβ(ρd )−1 d ln ρddTT =T max=0⇒˙y (t max )=p βd −1(15a)d 2ρβd (βd −1)[˙y (t max )]2.(15b)The third(logarithmic)derivative ofρis then found from Eq.(12)to bed3lnρβdd3yβd 3[˙y(t max)]3−3β′d8(βd−1)42β′2d−βdβ′′d (βd−1)+3β′d .(18b)(In going from(18a)to(18b),we used(15a,15b)).For a suﬃciently narrow interval of t around t max,it suﬃces to keep only the lowest(cubic)term in the Taylor expansion of lnρ(T)as a function of ln(T/T max):ln ρ(t)βd d3lnρdKK claim that the observedρ(T)stays within this mar-gin over only1.5decades,which is smaller than eventhe conservative estimate(23).(As it was discussed in Sec.V,a more realistic estimate of KK’s T-interval isone decade).A decrease inδby1%(δ=−0.01)leads to a weakly insulating behavior:ρ(T)increases by30%as T decreases by1.5decades.An increase inδby4% (δ=0.04)leads to a well-pronounced metallic behavior:ρ(T)drops by about a factor of two over1.5decades in T.These features are in quantitative agreement with theexperiment[15].(For the sake of simplicity,we assumed that parametersρ1and¯ρdo not depend on the density,i.e.,onδ.Taking these dependences into account should lead to even better agreement with the experiment.)We emphasize that noﬁne tuning between theβ-function andρd was used.If it is the competition be-tween the decrease in Drude resistivity with temperature and the localization eﬀects that leads to the maximum inthe observable resistivity,then theρ(T)-dependenceﬂat-tens out,as the density approaches the threshold for a maximum.It turns out that if the exponent p is not toobig(which is usually the case),thisﬂattening suppresses the variation ofρ(T)below the experimentally observablelevel over several decades in temperature.Even an over-simpliﬁed model[5]which does not take into account,e.g.,electron-electron interactions(except for as a pos-sible phase-breaking mechanism),can easily produce al-most constant resistivity in a temperature interval,which is two orders of magnitude wider than the experimentalone.Therefore,we do notﬁnd it too much of a“re-markable coincidence”that at some density the systemdemonstrates a fairly constantρ.We now turn to the data presented in Ref.[15].The authors emphasize strongly that at n=n3= 7.25×1011cm−2the resistivity is almost temperatureindependent in the temperature range35mK-1K.They also add thatρ(T)decreases with T for T>∼1.8K.It would be interesting to know what happens at interme-diate temperatures:1K<T<1.8K.This point beingunclear,KKﬁll in the missing temperature interval by combining their result with the one obtained on another system.Indeed,they write:“In combination with the results of Ref.[10](Ref.[52] of this paper–AMP)where the temperature-independent curve(with essentially the same value of resistivity)was observed in the temperature range250mk-1.8K in an-other2D system in silicon,we further allege that there is no observable T-dependence at n s=n c in the tem-perature range35mk-1.8K...”.(Ref.[15],p.3,second paragraph.)Parenthetically,we note that the resistivities of combined curves diﬀer by35%.As far as we understand,tempera-ture intervals of experiments on diﬀerent systems are not additive parameters,and thus the procedure described above is not justiﬁed.Summarizing this part of our discussion,we take the liberty to describe the experimental situation in the fol-lowing way:In a sample from the intermediate peak mobility range (where temperature dependence ofρis known to be quite weak at high T),one canﬁnd a density such thatρdoes not change for more than10%within about one order of magnitude in T.This statement is a re-sult of measurements on a single sample in the interval 100mK<T<1K(when a realistic estimation of the electron heating is taken into account).(It will be two samples if results of Ref.[52]for250mK<T<1.8K are taken into consideration.)In our opinion,there are neither theoretical nor exper-imental reasons to believe that the density corresponding to the weakestρ(T)-dependence is indeed the critical one.i.e.,thatρ(T→0)→∞andρ(T→0)isﬁnite for lower and higher densities,respectively.The lack of a pro-nounced temperature dependence ofρin a limited range of T does not signal any remarkable phenomenon and is well-described by a simple theory of Anderson localiza-tion in a temperature-dependent disorder(Ref.[5]).VII.ON THE APPARENT LINEAR TEMPERATURE DEPENDENCE OFρ(T)We now turn to point(2)of Ref.[15)]regarding the functional form of the observedρ(T)-dependence.Ac-cording to KK,this form is a)linear and b)qualitatively distinct from those observed by other authors.Fig.7 reproduces Fig.3b of Ref.[15],where the“almost lin-ear dependence”is demonstrated.The data in Fig.7is data5of Fig.1,displayed in truncated(T<400K)and full(T<1200mK)intervals.The truncated interval, in whichρ(T)is supposed to be“almost linear”,corre-sponds to Fig.3b of Ref.[15].We begin with an attempt toﬁt untruncated data5of Figs.1,7in the whole interval T<1.2K by an empirical expression[53]ρ(T)=ρ0+ρ1exp −T0。

常用岩芯描述英语词汇及简写

常用岩芯描述英语词汇及简写coordinate co 一致coordinate ord 座标coordinate ord 一致coquina coq 贝壳灰岩coral crl 珊瑚coralline corln 珊瑚的coralline corln 珊瑚状core c,- 岩心corehole CH 取心井corrected corr 校正好的corrected depth CD 校正井深correlate correl 对比cover cov 覆盖层cover cov 包括cream crm淡黄色cream crm奶油色crenulate cren 细褶皱crenulate cren 锯齿状cretaceous K 白垩系cretaceous K 白垩纪cretaceous Cret 白垩系cretaceous Cret 白垩纪crevice crev 裂隙crinkled crnk 褶卷曲crinkled crnk 成波状crinoid crin 海百合cross X 交错cross-laminated Xlam交错纹层cross-stratified Xstrat 交错层理crossbed Xbd 交错层crossbeding Xbdg 交错层理crum bly crmb 易碎的crum bly crmb 脆的crum pled crpld 挤压crum pled crpld 变皱crum pled crpld 扭曲crypto crp 隐crypto crp 隐蔽cryptoprefix crp 隐cryptoprefix crp 隐蔽cryptocrystalline crpxl 隐晶质的cryptofissile crpfisscryptograined crpgr 隐晶岩crystal xl 晶体crystal xl 结晶crystalline xln 晶质的crystalline xln 结晶的cube cub 立方的cube cub 立方体cubic cub 立方的cubic cub 立方的cubic foot CF 立方英寸cummulative cum累计的cut ct 切cut ct 割cut ct 馏点cut flourescence CF 溶液荧光cutting ctg 切割cutting ctg 切片cuttings ctgs 岩屑cuttings ctgs 钻屑cycle cyc 旋回cycle cyc 周期cycle per m inute CPM 转/分dacite dac 英安岩dark dk 暗的dark dk 深的darker dkr 暗的darker dkr 深的debris deb 岩屑debris deb 碎石decrease decr 减少decrease decr 降低degree deg 度degree deg 程度degree deg 方次dendritic dend 树枝的dendritic dend 多枝的dense dns 浓的dense dns 稠密的dense dns 密集的density dnsty 密度depositional depstnl 沉积的depositional depstnl 沉积作用的depth unit DU 深度单位description des 描述description des 说明dessication des 干躁剂determine dtrm确定determine dtrm决定determine dtrm限定detrital dtrl 碎屑的detritus dtrs 碎石development dev 发展development dev 开发deviation dev 偏的deviation dev 偏差devonian D 泥盆系devonian D 泥盆纪devonian devo 泥盆系devonian devo 泥盆纪diabase db 辉绿岩diagenesis diag 成岩作用diagonal diag 斜的diagonal diag 对角线的diameter dia 直径diametor dia 直径的diametor diam直径的diamictite diamic 杂岩diamictite diamic 混杂陆源沉积岩siffierent dif 差异siffierent dif 区别siffierent dif 不同diorite drdirty drty 泥土discontinuous discont 不连续的dolomite dol 白云石dolerite do 粗粒玄武岩dolerite do 辉绿岩dolomit ic dolc 白云石的dolomit ized dold 白云岩化dolomold dolmd 白云石穴dolomold dolmd 白云石晶模dolostone dolst 白云灰岩dominant dom主要的dominant dom占优势的druse drs 晶族druse drs 晶洞drusy drsy 晶族状dusky dky 微暗的maximum dip angle DMAX 最大倾角normal calculated D exponent DCN 正常D 指数earthy erthy 土状的earthy erthy 泥土的echinoidal ech 海胆类effective core porosity ECP 岩心有效孔隙度elevation elev 海拔高度elliptical elip 椭圆形的elongate elg 伸长状elongate elg 狭长状em bedded em bd 埋入的em bedded em bd 嵌入的eocene Eoc 始新世equivalent cirulating density E.C.D 等效循环密度equivalent m ud weight E,M.W 当量泥浆必重eroded erod 侵蚀的erosional eros 冲蚀erosional eros 侵蚀estim ated est 估计estim ated est 评价estim ated est 判断euhedral euhed 自形的euxinic eux 静海相的euxinic eux 闭塞环境evaporite evap 蒸发岩evaporite evap 蒸发盐example ex 例子excellent excel 优良的excellent excel 极好的exposed exp 暴露的external upset end EUE 外加厚extraclast exclas 外来碎屑extraclastic ex clas 外来碎屑extremely extr 极度extremely extr 极端extremely extr 终极fabric fab 结构fabric fab 构造facet fac 磨光面facet fac 刻面faint fnt 微弱的faint fnt 淡的fair fr 好的fair fr 公正fault flt 断层feet ft 英尺feldspar fld 长石fenestra fen 模孔fenestra fen 窗孔ferro-m ag fe-m ag 铁锰铜和金ferruginous ferr 含铁的ferruginous ferr 铁质few fw 少量fibrous fibr 纤维状fibrous fibr 纤维质fill fl 冲填filtercake FC 泥饼fine f 细fine f 细粒的fine f 好的firm frm硬firm frm坚硬fissible fis 裂变物质fissible fis 易剥裂的flag of shale FSHA 泥岩标志flaggy flg 断层flaggy flg 薄层flake flk 薄片flake flk 磷片flat fl 平的flat fl 无光泽的flourescence flour 荧光foliated fol 叶片状foliated fol 薄层状form ation fm地层form ation fm形成form ation fm建造form ation flacter FC 地层因素fom ation water Fm W 地层水fossil foss 化石fossil foss 含化石的fossiliferous foss 化石fossiliferous foss 含化石的fracture frac 断口fracture frac 裂缝fracture frac 破裂fragm ent frag 碎块fragm ent frag 碎片fragm ent frag 碎屑frequent freq 频繁frequent freq 经常frequent freq 常见的fram estone fram est 骨架岩fresh frs 新鲜的fresh frs 淡的fresh break FB 新破碎的fresh water Frw 淡水friable fri 易碎的friable fri 脆性的fringe frg 边缘fringe frg 条纹friosted fros 无光泽的good g 好gradational contact grad-con 整合接触关系grade grd 粒级grade grd 坡度grade grd 等级gradient grad 梯度grading grdg 分选grading grdg 分级grain gr 粒grain gr 颗粒gradual grad 逐渐的grainstone grst 粒状灰岩grainstone grst 颗粒岩gram/liter g/l 克/升granite grnt 花岗岩granite wash grntw 花岗冲积物granite wash GW 花岗冲积物granitic grntc 花岗岩的grano-diorite grndior 花岗闪长岩granodiorite grndior 花岗闪长岩granule gran 细粒granule gran 粒砂granulestone granlst 细粒granulestone granlst 颗粒岩grapestone grap 笔石grapestone grnpst 葡萄状灰岩graptolite grap 笔石gravel gvl 砾石gravel gvl 砂砾gravity grav 重力gravity grav 比重gray gy 灰色greasy gsy 油性的greasy gsy 多脂的green gn 绿色的greywacke gywk 杂砂岩greywacke gywk 硬砂岩grit gt 粗砂质的gritty gt 粗砂质的groove cast grv cst 凹槽ground grd 地面ground level GL 地平面ground level GL 地平线group G 团体gumm y gm y 胶质gumm y gm y 粘性gypsiferous gyp 含石膏gypsum gyp 石膏hackly hkl 锯齿状hackly hkl 粗糙的haem atite haem赤铁矿haem atiteic haem赤铁矿halite hal 石盐halite hal 岩盐haliteic hal 石盐haliteic hal 岩盐hard hd 坚硬的head hd 头顶head hd 源头heavy hvy 重的heavy hvy 强烈的heavy fuel oil HFO 重燃油heterogeneous hetr 非均质的hexagonal hex 六边形hexagonal hex 六角形high hi 高的high hi 强烈的high gas oil ratio hgor 高气油比high pressure hp 高压high tem perature HT 高温high viscosity HV 高粘性high water loss HWL 严重失水holocene hol 全新始homogeneous hom均质的homogeneous hom均匀的horiz hor 层horiz hor 层位horiz hor 水平线horizontal hztl 水平的horizontal hztl 强烈的hornblend ho 角闪石horse power hp 马力hour hr 小时hydrocarbin hycbn 烃hydrocarbin hycbn 碳氢化和物hydrochloric acid Hcl 盐酸hydrogen ion concentration ph 氢离子浓度hydrogen sulphide H2s 硫化氢hydrostatic gradient HG 静液压力梯度hypabyssal rock hypb rk 浅成岩hypabyssal rock hypb rk 半深成岩thick of mud cake HMC 泥饼厚度inter int 在....中间idest ie 即idest ie 就是igneous rock ig 火成岩igneous rock ig 岩浆岩illite illit 伊利石illiteic illit 伊利石imbeded imbd 埋入的impermeable imperm不透明的impression im p 压痕impression im p 印记impression im p 影响in part i/p 部分的inch in 英寸included incl 包括included incl 包体increase incr 增加increase incr 增长increaseing incr 增加increaseing incr 增长indistinct indst 不清楚indistinct indst 不易区别的indurated ind 固结的indurated ind 硬化的initial producation IP 初始产量input/output I/O 输入/输出insetnal upset ends IUE 内加厚inside diameter ID 内径insoluble insl 不熔的interbeded intbd 互层的interbeded intbd 间层的intercalated intcl 插入intercalated intcl 加入intercalated intcl 夹层intercrystalline interxln 晶间的interfingered intfg 泄形夹层interfingered intfg 指状交错intergranular intgran 粒间的intergrown intgwn 共生intergrown intgwn 互生intergrown intgwn 连晶interlaminated intlam层间的interlaminated intlam薄层相interparticle intpar 颗粒间的interrupt INT 打断intersticies intst 潮间的intersticies intst 潮区的interstitial intstl 空隙的interstitial intstl 隙间的interval intvl 层段interval intvl 井段interval intvl 间距intraparticle intrapar 粒间的ironstone fest 含铁矿石ironstone fest 铁岩irregular irr 不规则的joint jts 节理joint jts 接头joint jts 结合jurassic Ju 侏罗系jurassic Ju 侏罗纪kaolinitic kaoc 高岭土laminated lam纹层状laminated lam页状lavender lav 淡紫色light lt 淡色的light lt 浅色的lime lm石灰limestone ls 石灰岩limonite lm n 褐铁矿limonite lm n 褐铁矿的limonitic lm n 褐铁矿limonitic lm n 褐铁矿的limy lm y 含灰质的limy lm y 有粘性的lithic lit 岩屑的lithic lit 岩性的lithic lit 石灰的lithology lith 岩性学llittle ltl 小little ltl 少llittle ltl 不多的local loc 局部的local loc 地方的lump lmp 团块lumpy lmpy 块状luster lstr 光泽lutite lut 细屑岩lutite lut 泥质岩magnetic mgn 磁性的magnetite m gt 磁铁矿marble mbl 大理岩marble mbl 大理石marginal mrgnl 边缘的marginal mrgnl 边际的marine m arn 海的marl mrl 灰泥marl mrl 泥灰岩marly mrl 灰泥marly mrl 泥灰岩marlstone m rlst 硬泥灰岩marly mrlyf 泥灰岩maroon m ar 栗色maroon apr 紫酱的massive m as 块状的material m ati 物质matrix m ax 基质matrix m ax 母质matrix m ax 填质matter m at 物质matter m at 物体medium m中间的mesozoic Mz 中生代metam orphic m et 变质的metam orphic rock m eta 变质岩metasom atism m sm交代变质作用mica mic 云母micaceous m icas 云母状的micaceous m icas 含云母的micrite m icr 微晶灰岩micro micr 小micro micr 微middle m id 中部middle m id 中期的minimum m in 最小的minor m nr 次要的minor m nr 较小的minute min 分minute min 微小的miocene m io 渐新统moderate m od 中等的moderate m od 适度的mont m orillonitic m ont m oril 微晶高岭土mottled m ot 斑点的mottled m ot 杂色的muscovite m usc 白云母nacreous nac 珍珠的nacreous nac 珍珠状的neogene neo 下第三纪net oil sand NOS 纯油砂no n 无no cut NCT 无岩屑no flourescence NF 无荧光no recovery NR 未取的no sample N.S 无样品no show NS 无显示no visible porosity n.v.p 无可见孔no water NW 无水nodule nod 结核non nn 无non-upset Nu 不加厚noncalcareous ncal 不含钙的noncommercial NC 无商业价值的none ne 无not reached NR 未达到的not recorded NRec 未记录的novaculite novac 燧石岩number No 号码numerous num许多的odor stain fluoresence OSF 气味油斑及荧光odor taste and stain OTS 气味油感及油斑odor taste stain flouresence OTSF 气味油感油斑荧光oil sand oil sd 油砂oil saurce rock osr 油源岩oil stain ostn 油斑oil-cut m ud OCM 油浸泥浆old well OW 老油井oligocene olig 渐新世olive olv 橄揽olive olv 橄榄色的opaque op 不透明的opaque op 不透明的opaque op 不透明的opaque op 不透明的opaque op 不透明的opaque op 不透明的opaque op 不透明的orange oran 桔黄的orange oran 橙色orbitolina orbit 有孔虫类ordovician o 奥陶系ordovician Ord 奥陶系organic org 有机的organic org 有机的orthoquartzite Q 正石英岩orthoquartzite QTZ 正石英岩ostracoda ost 介形虫overgrowth ovgth 附生overgrowth ovgth 次生overgrowth ovgth 加大pebble pbl 砾石pebble pbl 卵石pale pl 浅色pale pl 淡色pale pl 暗淡色paleocene paleo 古新世paleogene pg 上第三纪part pt 部分part pt 成分particle par 微粒particle par 颗粒partly ptg 夹层partly ptg 断裂partly pty 部分的partly pty 局部的patch pch 碎片patch pch 斑点patch pch 块礁pearly luster prly luster 珍珠光泽pebble PEE 小砾石pebbly pbly 含砾石的pellet pel 球粒pellet pel 团粒permian P 二叠系permian perm二叠系phisphate phos 磷酸盐的phosphatic phos 磷酸盐的phlogopite phlog 金云母phosphate phos 磷酸盐phyllite phyl 千牧岩phyllite phy 千牧岩phyllite phy 鳞片状矿物pin-point pp 顶端pin-point pp 极准确pin-point porosity ppp 极小空隙性pink pink 粉红色pisolite piso 豆石pisolite piso 豆粒pisolite piso 豆状岩pitted pit 坑的plagioclase plsg 斜长石plant fossols pl fos 植物化石plastic plas 可塑的plastic plas 塑性的platy plat 板状的pleiocene pllio 更新世poor p 贫的poor p 稀少的porosity por 孔隙度porosity por 多孔的porous por 孔隙度porous por 多孔的pounds per square inch psi 每平方荧寸磅precam brian Pe 前寒武系precam brian Prec 前寒武系predominant pred 主要的predominant pred 突出predominate pred 主要的predominate pred 突出purple purp 紫色purple purp 紫红色pyrite pyr 黄铁矿pyrobitumen pyrbit 焦沥青pyroclastic pyrclas 火成碎屑pyroxene pyrxn 辉石pure 纯的quartz qtz 石英quartzite qtzt 石英岩quarzitic qtzc 石英岩的quaternary Q 第四纪quaternary Q 第四系quaternary Quat 第四纪quaternary Quat 第四系rainbow show of oil RBSO 彩色油花显示rare r 稀有的rare r 罕见的recrystallized reslzd 重结晶recrystallized reslzd 再结晶red rd 红色red rd 红色的reef rf 礁reef rf 生物礁reef rf 矿脉residual oil RO 残余油residual oil RO 渣油residual oil saturation Ros 残余油饱和度residual res 残余residual res 残余物residue res 残余residue res 残余物round rnd 圆形rubbly rbly 碎石状的rubbly rbly 角砾状的rudstone rdst 砾屑碳酸岩salt x 盐salty x 盐sam ple spl 样品sam ple as above a.a 岩性同上sam ple as above a/a 岩性同上sand sd 砂sandstone sst 砂岩sandy sdy 砂质的saturate sat 饱和的saturate sun 饱和度saturatioon sat 饱和的saturatioon sat 饱和度scales sc 尺度section sec 薄片section sec 阶段sediment sed 沉积物sediment sed 沉积的sedimentary sed 沉积物sedimentary sed 沉积的selenite sel 透石膏shale sh 页岩shale density S.D 页岩密度shaled out shout 尖灭shaled out shout 泥岩封闭shaly shy 页岩状shaly shy 页岩质siderite sid 菱铁矿silica sil 氧化硅silica sil 硅质silica sil 硅酸siliceous sil 氧化硅siliceous sil 硅质siliceous sil 硅酸silky slky 丝状silky slky 光滑的silt slt 粉砂silt slt 淤泥siltstone sltst 粉砂岩silty slty 粉砂质的silurian S 志留系silurian Sil 志留系silvery avy 银色的similar sim相似的similar sim相近的size sz 尺寸size sz 规模skeletal skel 骨骼的skeletal skel 骨架的slabby slab 板状的slant range S/R 斜距slate sl 石板slickenside sks 断面slickenside sks 擦痕slickenside sks 擦痕面slight sl 轻的slight sl 薄的slight show of gas SSG 轻微气显示slight show of oil SSO 轻微油显示slow slw 慢sm all sml 少sm all sml 少量sm ell sm ll 气味sm ooth sm光滑的sm ooth sm平坦的soft sft 软的soluble sol 可溶的solution sol 溶液solution sol 溶解sort srt 种类sort srt 类别sort srt 性质sorted srtd 分选的sorting srtdg 分选作用spar spr 亮晶spar spr 晶石sparry spr 亮晶sparry spr 晶石spare parts sp 备件sparse sps 稀少的sparse sps 稀疏的sparsely spsly 稀少的sparsely spsly 稀疏的species sp 种类species sp 性质specific gravity sp.sg 相对密度specific gravity sp.sg 比重specific gravity sg 相对密度specific gravity sg 比重speckled spec 有斑点的sphalerite sphal 闪锌矿spherical sphcl 球形状的spherical sphcl 圆的spherules sph 小球spicule spic 骨针spicule spic 针状体spicular spic 骨针spicular spic 针状体splintery splin 裂片状splintery splin 易碎裂spores spo 孢子sponge spg 海绵sponge spg 海绵状物spit spt 点spit spt 斑点spotted sptd 斑点的spotted sptd 成点的spotty spty 斑状spudded spd 开始的spudded spd 开钻squsre inch sq in 平方英寸squeeze sqz 挤压squeeze sqz 挤水泥stain stn 油斑strata strat 地层strata strat 分层strata strat 成层stratify strat 地层stratify strat 分层stratify strat 成层stratigraphic test ST 地质探井stratigraphic test ST 参数井stratum strat 地层streak strk 条纹streak strk 薄层streak strk 夹层striated stri 有条纹的stringer strg 低产井stringer strg 低平段strom atoporoid strom层孔虫类strong str 强的strong str 有力的structure struc 构造structure struc 结构stylolite styl 缝和线stylolitic styl 缝和线sub- sb 次subangular subang 次棱角状subangular SA 次棱角状subroundrd subrnd 次圆状subhedral sublitc 半自形的sublithic sublitc 次石质的subrounded subrd 次圆状subrounded subrd 半磨圆的subrounded SR 次圆状subrounded SR 半磨圆的subspherical supsph 次长形sucrose suc 蔗糖sulfur sul 硫sulfur sul 硫磺sulfur s 硫sulfur s 硫磺sulfur water SuW 含硫的水surface surf 地面surface surf 面suspend susp 悬suspend susp 吊suspend susp 停止syncline syncl 向斜syntaxial syn 共轴的tabular tab 平板状的tabular tab 扁平的tan tn 棕黄色tan tn 褐色tatal productin tim e TPT 总生产时间tem porary abandoned TA 临时弃井tem prature temp 温度tem prature difference tem pff 温差tem prature formation TF 地温terriginous ter 陆源的terriginous ter 陆成的tertiary T 第三纪tertiary Tert 第三纪texture tex 结构therm al th 热的therm al th 热力的thick thk 厚的thick thk 粗的thick thk 浓的thin thn 薄的thin thn 细的thin thn 稀的thin section T.S 薄的部分thin-bedded t.b 薄层thread thd 螺丝thread thd 丝扣through thru 通过through thru 经由through out thru 到处through out thru 完全tight tt 致密的tight tt 紧张的tight ti 致密的tight ti 紧张的tim e-depth chart T-Dchart 时深曲线top tp 顶部top tp 上部top T 顶部top T 上部top eroded TE 顶部被侵蚀top of cem ent toc 水泥返高top of sand TOS 顶部砂层total gas TG 全量total tepth TD 总深度total volum e TV 总体积total weigh Tw 总重tough tgh 刚硬的tough tgh 粘稠的trace tr 轨迹trace tr 痕迹translucent trnsl 半透明的transparent transp 透明的treat trt 处理treat trt 论述triassic Tr 三叠纪triassic Trias 三叠纪trilobite trilo 三叶虫tirp gas TG 后效气tirp gas TG 起下钻气triping Tr 起下钻tripoil Trip 硅藻土tripolitic Trip 硅藻土tuff tuf 灰质tuffaceous tuf 凝灰岩type typ 类型type typ 标志unconformity uncf 不整合unconsolidated uncons 未固结的underclay uc 低粘岩underlying undly 下伏的undifferentiated und 无差别的undifferentiated und 一致的uniform unif 相同uniform unif 一致unknown unk 未发现的unsuccessful uns 失败的upper upr 上部under gauge U.G 不规范的vadose vad 渗流variable var 变量variable var 可变的variableation var 变量variableation var 可变的varicolored vcol 杂色的variegated vgt 杂色的variegated vgt 多样的varved vred 纹泥的vein vn 脉vein vn 矿脉vein vn 岩脉veinlet vnlet 细脉veinlet vnlet 小静脉velocity vel 速度vermillon verm朱色的vermillon verm朱砂vertical vert 垂直的very v 很very v 极very coarse grained VCG 极粗的very fine grained VFG 极细的vesicular ves 多孔的vesicular ves 多泡的violet vi 紫色violet vi 紫罗兰色volcanics volc 火山岩volcanics volc 火山物质volcaniclastic vol c 火山碎屑vug vug 晶洞vug vug 孔洞vuggy vug 晶洞vuggy vug 孔洞weak wk 微软的weak wk 软的weathered wthrd 风化的weathering wthrg 风化作用wedge out wdgot 尖灭white wh 白色with w 含with w 带with w 夹cut fluorescence cut 滴照direct dir 直照kaolin kao 高岭土containing contg 含gravity gvl 砾石middle 中部lower 下部intercalated 夹层interbedded 互层porosity 多孔的fractured 裂缝状platy 片状paminated 层状massive 块状fissile 易剥状calci te 方解石dolomite 白云岩sulfats 硫酸岩iron oside 氧化铁sillica 硅石siderite 菱铁矿matrix 基质medium 中间com pact 致密moderate 中等的cem ent 胶结fragm ent 碎片spotted 有斑点的rare 稀少的Fossil 化石shell 贝壳concretion 结核form ation 地层nodule 团块with 有irregular 不规则的friable 易碎的large 大的sm all 小的pole 灰白的pink 桃色blue 蓝色glauconiete 海绿石Pyrite 黄铁矿hornblend 角闪石chlorite 绿泥石mica 云母lingite 褐煤chert 燧石calcareous 钙质soliceous 硅质sandy 砂质muddy 泥质silty 粉砂质shaly 泥质conglom erate 砾岩breccia 角砾岩flake 片状metam orphic 变质的toste 味dye hand 染手slightly 较微的top 顶部bsse 底部upper 上部的under 下部的above 在....上方less than 小于more than 大于interbedded 层间的ripple m ark 痕slichenside 擦痕面alternation 互层carbonaceous 碳质plant 植物dip 倾角geology 地质unconformity 不整合induration 固结unconsolidated 未固结cem entation 硬化com paction 紧密schist 片岩schist 片状的stain 侵然stained 侵然staining 侵然stylolit 缝合线weatheved 风化的absent 缺失altered 蚀变的asphalt 沥青band 夹层bedding 层理bedding 分层background gas 背景气carbonaceous 碳质的carbonized 碳化的conchoidal 贝壳状carbon tetrachloride 四录化碳rock salt 盐岩coaly shale 碳质页岩marly 泥灰岩chalky 白垩质dolomit ic 白云质car banate 碳酸岩calcirudite 钙质砾岩granite 花岗岩cobble 大的砾core 岩心pelletoid 球粒鲕micropelletoid 微粒鲕ooid 鲕粒other 其它的biotote 黑云母barite 重晶石lithology 岩性transparent 透明的without 没有poorly 差的moderately 中等的well 好的trace 微量的good 好的fair 较好的granules 细的砾pebble 中的砾sm all 小的large 大的thick 厚的thin 薄的platy 板状的sponty 松软的com pact 较致密的sm ooth 光滑的conchoidal fracture 贝壳状断口homogeneous 均质的weatnered 风化的banded 条带状的fine 细的coarse 粗的sticky 造浆的brittle 脆的nodule 团块micro crystalline 微晶cryptio crystalline 隐晶aphanitic 隐晶质very fine crystlline 粉晶fine crystlline 细晶medium crystalline 中晶coarse crystalline 粗晶piebald 花斑about 大钩strong 强weak 弱oil semll in general 油味spotty oilstain 油斑patchy oil stain 部分油斑streaky oil stain 油斑条痕uniform oil stain 全部油斑gold 金黄色grain size 粒径crystal 晶体characteristics 特性major 主要的minor 次要的hardness 硬度porosity 孔隙度oil shows 油显示lamina 薄层stratum单层group 系foult 断层oil stained 油浸oil patch 油斑oil spotted 油斑oil trace 油迹oil saturated 油浸sedimentary rock 沉积岩igneous rock 火山岩metam orphic rock 变质岩carbonate rock 碳酸岩silicste 硅酸盐lasalt 玄武岩salt rock 盐岩flint 燧石plastic 塑性的swell 膨涨com pact 坚实的com pact 紧密的dense 稠密的plastic 可塑的earthy 土状wire 安装biocalcarenite 生物砂屑灰岩biocalcilutite 生物泥屑灰岩biocalcirudite 生物砾屑灰岩biocatalysator 生物促长质biocatalyst 生物催化剂biocenology 生物群落学biocenose 生物群落biocenotic association 生物群落共生体biochemical conversion 生物化学转化biochemical cycle 生物化学循环biochemical degradation 生物化学降解biochemical engineering 生物化学工程biochemical factor 生物化学因素biochemical fuel-cell 生物化学燃料电池biochemical gas 生物化学气biochemical methane 生化甲烷biochemical mineralization 生物化学矿化作用biochemical origin 生物化学起源biochemical oxygen demand 生化需氧量biochemical pollution criteria 生物化学污染标准biochemical process 生物化学法biochemical reaction 生物化学反应biochemical reduction 生化还原biochemical 生物化学的biochemigenic rock 生物化学岩biochemistry 生物化学biochronologic 生物年代的biochronology 生物年代学biochronometer 生物钟biochronostratigraphic unit 生物年代地层单位biochronostratigraphic 生物年代地层的biochronotype 生物年代型biocide 杀生物剂bioclast 生物碎屑bioclastic calcarenite 生物碎屑砂屑灰岩bioclastic grainstone 生物碎屑粒状灰岩bioclastic limestone 生物碎屑灰岩bioclastic packstone 生物碎屑泥粒灰岩bioclastic rock 生物碎屑岩bioclastic wackestone 生物碎屑粒泥灰岩bioclastics 生物碎屑岩bioclimate 生物气候bioclimatic zonality 生物气候分带性bioclimatic zonation 生物气候分带bioclimatic zone 生物气候带bioclimatics 生物气候学bioclimatology 生物气候学biocoene 生物群落biocoenology 生物群落学biocoenose 生物群落biocoenosium 生物群落biocoenotic connection 生物群落关联biocoenotics 生物群落学biocolloid 生物胶体biocommunity 生物群落bioconstructed facies 生物建造相bioconstructed limestone 生物灰岩bioconversion 生物转化bioctyl 联辛基biocybernetics 生物控制论biocycle 生物带biodegrability 生物降解能力biodegradability 生物降解性biodegradable detergent 生物降解洗涤剂biodegradable fluid 生物降解液biodegradable polymer 可生物降解的聚合物biodegradable surfactant 生物降解表面活性剂biodegradable 生物可降解的biodegradation oil 生物降解油biodegradation pathway 生物降解途径biodegradation 生物降解作用biodemography 生态统计学biodeposition 生物沉积作用biodeterioration 生物退化biodetritus 生物碎屑biodinetic temperature limit 生物活动温度临界biodynamics 生物动力学biodyne 生物因素bioecology 生物生态学bioelectric current 生物电流bioelectricity 生物电bioelectronics 仿生电子学；生物电子学Bioendoglyphia 内生迹纲bioenergetics 生物力能学bioengineering 生物工程bioenvironmental 生物环境的bioerosion structure 生物侵蚀结构bioerosion 生物侵蚀作用Bioexoglyphia 外生迹纲biofacial zone 生物相带bilge block 底边枕木bilge board 舱底污水道盖板bilge bracket 舭肘板bilge chock 消摇龙骨bilge compartment 浸水舱bilge injection 舱底水注入装置bilge keel 舭龙骨；消摇龙骨bilge keelson 舭龙筋；舭部内龙骨bilge line 舱底水吸水管bilge main 舱底水总管bilge piece 消摇龙骨bilge pipe 舱底吸水管bilge stringer 舭部纵桁bilge suction 舱底吸管bilge water 船底污水bilge ways 底边板；滑板bilge 腹部bilging 船底破裂BILI 层间封隔水泥胶结指数bilianic acid 胆汁烷酸biliary calculus 胆石bilichol 胆汁醇bilicyanin 胆青素biliminal chain 双侧限地槽链biliminal geosyncline 双侧对称地槽bilinear flow 双线性流动bilinear form 双线性型bilinear function 双线性函数bilinear interpolation 双线性插值法bilinear model 双线性模型bilinear relation 双线性关系bilinear transform 双线性变换bilinear transformation 双线性变换bilinear 双线性bilinearity 双线性bilingual edition 双语版bilirubin 胆红素biliverdin 胆绿素bill in domestic 本币汇票bill of clearance 出港申报表bill of entry 入港报关单bill of exchange 汇票bill of lading 运货单bill of materials 材料单bill of quantities 工程量表bill of the hook 吊钩的锁栓bill to order 需签字照付的票据bill 帐单billboard 揭示牌billed price 帐单价格billet 木柴块；短条；坯段；钢坯；错齿饰；字条billeteer 钢坯剥皮机billibit 十亿位billicycle 千兆周billietite 黄钡铀矿Billingsastraea 毕灵星珊瑚属billion electron volts 十亿电子伏billion 千兆billisecond 毫微秒billon 金、银与其他金属的合金billow forming 热胀成型billow 巨浪billy club 镐锤bilogarithmic diagram 双对数图bilogarithmic graph 双对数图bimaceral 双组分显微煤岩类型bimag 双磁芯bimatron 电子束注入式磁控管bimetal 双金属bimetallic catalyst 双金属催化剂bimetallic cell 双金属电池bimetallic corrosion 电偶腐蚀bimetallic electrode 双金属电极bimetallic strip 双金属片bimetallic system cell 双金属温度计bimetallic 双金属的bimetallism 双金属作用bimirror 双镜bimodal cosets 双向叠合组bimodal cross-bedding 双向交错层理bimodal current rose 双向水流玫瑰图bimodal distribution 双峰分布bimodal igneous activity 双向火成活动bimodal rift volcanism 双向裂谷火山活动bimodal size distribution 双峰粒度分布bimodal volcanic complex 双向火山杂岩bimodal 双峰的；双值的；双模的；双向的bimolecular law 双分子反应定律BG 浮心与重心间的距离Bg 宽轨距BG 锥齿轮BG 总线批准BGC 二进制增益控制BGC 凝析油桶数BGG 背景气量BGL 井眼几何形状测井BGMA英国齿轮制造商协会BGO 锗酸铋探测器BGS 英国地质调查所BGT 井眼几何形状测井仪BH loop 磁滞回线BH 布氏硬度BH 观察软管BH 每小时桶数BH 钻孔BHA behavior 底部钻具组合性能BHA changes 改变底部钻具组合BHA components 底部钻具组合组件BHA data base 底部钻具组合数据库BHA deforms 底部钻具组合变形BHA directional behavior 底部钻具组合定向特性BHA dynamics 底部钻具组合动态BHA finite element model 底部钻具组合有限元模式BHA performance 底部钻具组合特性BHA selection 底部钻具组合的选择BHA trips 为改变底部钻具组合而进行的起下钻作业BHA底部钻具组合BHA’s relative rigidity 底部钻具组合的相对刚度BHAP 底部钻具组合计算机程序BHC mode 井眼补偿方式BHC 井底油嘴BHC 井眼补偿声波测井BHCK 井底节流器BHCS 井眼补偿声波测井BHCT 井底循环温度bhd 舱壁bhel 河床沙岛BHF 井内流体BHFP 井底流动压力BHFP 井底破裂压力BHFT 井底流动温度BHGM density 井下重力测量密度BHGM 井下重力仪BHHP 井底水马力BHHP 钻头水马力BHIP 原始井底压力BHM 井眼物质Bhn. 布氏硬度BHP 澳大利亚布洛肯山控股有限公司BHP 锅炉马力BHP 井底模式BHP 井底压力BHP 英制马力BHP 制动马力BHPC 关井井底压力BHPC 井底压力变化bhpf 井底流动压力bhpsi 井底关井压力BHRA英国流体力学研究协会BHS 井底取样器BHS 井眼状况BHSIP 关井井底压力BHST 井底标准温度BHST 井底静态温度BHT 井底温度BHTV 井下电视BI 胶结指数BI 绝对安培BI 双向的Bi 铋bi- 二bi-component 双组分bi-coordinate system 双坐标系bi-directional counter 双向计数器bi-directional folded-type prover system 双向折叠型标定系统bi-directional pig 双向清管器bi-directional pipe prover 双向管式标定装置bi-directional slip 双向卡瓦bi-metal liner 双金属缸套bi-polar machine 双极电机bi-product pipeline 两种油品的管线bi-rotor pump 双转子泵bi-telephone 头戴双耳耳机bending gang 弯管小队bending glide 挠曲滑动bending iron 弯钢筋搬头bending line 弯度线bending machine 弯管机bending mandrel 弯管芯bending modulus 弯曲模量bending moment arm 弯曲力臂bending moment 挠矩bending party =bending crewbending radius 弯曲半径bending restrictor 弯曲限制器bending roll 卷板机bending schedule 弯钢筋表bending sets 冷弯管外胎具bending shoe 弯管子用的架垫bending strain 挠应变bending strength 抗弯强度bending stress 弯曲应力bending sub 弯接头bending team =bending crewbending test 弯曲试验bending trestle 弯管工作台bending yield point 抗弯屈服点bending 弯曲；挠曲；配曲调整；偏移；折曲；无线电波束曲折；弯头bendover price 炼厂所付每桶油价bends 潜水病bendway 深水槽beneficial 有利的；有使用权的beneficiary party 受惠方beneficiate 增效beneficiated bentonite 增效膨润土benefit cost analysis 效益成本分析benefit 利益benefitshazards of acidizing 酸化的利弊Benfield process 本菲尔德法Benfield unit 本菲尔德装置Benioff plane 贝尼奥夫面Benioff seismic zone 贝尼奥夫地震带Benioff zone 贝尼奥夫带；俯冲带；板块消亡带benito 飞机导航装置Bennettitaceaeacuminella 本内苏铁粉属Bennettitaceaeinvolutella 具环单沟粉属Bennettiteaepollenites 原本内苏铁粉属Benneviaspis 班涅夫鱼属bent bar anchorage 弯筋锚固bent chunk 弯曲块体bent cleavage 弯曲劈理bent drill pipe 弯钻杆bent housing motor 弯壳体泥浆马达bent housing 弯外壳定向钻井用支座bent multi-turbodrill 复式弯涡轮钻具bent nose pliers 歪嘴钳bent pipe 弯管bent rod 弯曲抽油杆bent spanner 弯头扳手bent stream tip 曲流喷嘴bent sub 弯接头。

Laser nano-manufacturing – State of the art and challenges

Laser nano-manufacturing–State of the art and challengesLin Li(1)a,*,Minghui Hong b,Michael Schmidt(3)c,Minlin Zhong d,Ajay Malshe(2)e, Bert Huis in’tVeld(3)f,Volodymyr Kovalenko(1)ga Laser Processing Research Centre,School of Mechanical,Aerospace and Civil Engineering,The University of Manchester,M139PL,UKb Department of Electrical and Computer Engineering,National University of Singapore,Singaporec Photonic Technologies,FAU Erlangen-Nuremberg,Germanyd Department of Mechanical Engineering,Tsinghua University,Chinae Department of Mechanical Engineering,University of Arkansas,USAf Department of Mechanical Engineering,University of Twente,The Netherlandsg National Technical University of Ukraine,Ukraine1.IntroductionThe need for nano-manufacturing is dictated not only by the requirement of increasingly sophisticated devices and structures with novel properties but also by the trend of decreasing component sizes,material usages and energy consumption of products.To meet the demand for product miniaturization and nano-material and structures enabled novel functionality,a logical step is to achieve the desired nano precision and resolution through the development and wide implementation of nano-fabrication technologies[78,119].Nano-scale manufacture refers to the production of structures,materials and components with at least one of lateral dimensions between1nm and100nm including surface and sub-surface patterns,3D nano structures, nanowires,nanotubes and sers have provided important opportunities in the realisation of nano-manufacturing.This paper reviews the progress in the development of laser based nano-manufacturing technologies and associated sciences in order to understand the state of the art and challenges.Fig.1shows the scope of the paper with three main areas of focus:(1)laser fabrication technologies for surface and subsurface nano struc-tures including nearﬁeld and farﬁeld techniques,(2)laser synthesis of nano materials including nanoparticles,nanowires and nanotubes,(3)laser fabrication of3D nano structures and devices primarily based on additive or bottom-up nano-manu-facturing techniques.Their industrial applications and scientiﬁc/ technological challenges are ser fabrication of surface nano-structures2.1.Diffraction limits to laser beamsLaser materials processing has been successfully applied in industry for several decades for cutting,welding,drilling,cleaning, additive manufacturing,surface modiﬁcation and micro-machin-ing.In most cases,the feature size and resolution of machining are above1m m.One of the reasons for the limited resolution is the diffraction limit of the laser beams in the farﬁeld(where the target surface from the optical element is greater than the optical wavelength)governed by:d¼l2n sin a(1) where d is the minimum beam spot diameter,l is the laser wavelength,n is the refractive index of the medium of beam delivery to the target material and a is the beam divergence angle. The best theoretical resolution is therefore around half of the laser wavelength.For most high power engineering lasers the optical wavelengths are within248nm–10.6m m.Therefore,there are considerable challenges to achieve nano-scale(100nm)resolu-tion in direct laser fabrication of surface structures.To improve the fabrication resolution a number of approaches have been considered including the use of high numerical aperture optics and shorter wavelength light sources.For example,deep ultra-violet(DUV,ArF193nm)laser sources have been used in producing lines of130nm and90nm lithography(32nm and 45nm with optics immersed a high refractive index liquid).To achieve smaller surface patterning feature sizes,F2lasers of 157nm wavelength and extreme ultraviolet(EUV)Xe or Sn plasma systems with a13nm wavelength are used for nanolithography. However,these sources are costly,low output power and unstableCIRP Annals-Manufacturing Technology60(2011)735–755A R T I C L E I N F OKeywords:LaserNano manufacturing Material A B S T R A C TThis paper provides an overview of advances in laser based nano-manufacturing technologies including surface nano-structure manufacturing,production of nano materials(nanoparticles,nanotubes and nanowires)and3D nano-structures manufacture through multiple layer additive techniques and nano-joining/forming.Examples of practical applications of laser manufactured nano-structures,materials and components are given.A discussion on the challenges and outlooks in laser nano-manufacturing is presented.ß2011CIRP.*Corresponding author.Contents lists available at ScienceDirectCIRP Annals-Manufacturing Technology journal homepage:/cirp/default.asp0007-8506/$–see front matterß2011CIRP. doi:10.1016/j.cirp.2011.05.005in light intensity.Strong absorption of the UV light by air molecules requires the nanolithography to be carried out in a vacuum or dry high purity N 2gas protection chamber.How to overcome the optical diffraction limit with stable UV or visible,IR light sources is attracting much research interests in the world.Near ﬁeld optics utilizing evanescent waves at the close proximity (within the length of the light wavelength)from the focusing optics have been recently applied for laser based nano-fabrications beyond the diffraction limits.In addition,femto second pulsed lasers have been used to achieve far ﬁeld nano-resolution fabrication based on ablation threshold setting of the Gaussian beam proﬁle of the lasers and non-linear light absorption ser radiation on scanning probe tips for nano-fabrication is not included in this paper as it was reported elsewhere [111].In the following sections,recent developments in near ﬁeld laser nano-fabrication techni-ques,far ﬁeld femto second laser nano-fabrication and laser induced self-organising nano-ripple formations are summarised.2.2.Scanning near ﬁeld photolithography (SNP)using laser coupled near ﬁeld scanning optical microscopy (NSOM)SNP is based on the coupling of a laser beam (e.g.a frequency doubled argon ion laser at l =244nm)with an optical ﬁbre based Near-ﬁeld Scanning Optical Microscope (NSOM,ﬁrst demonstrated in 1992)with a very ﬁne tip (typically 50nm)and very close (10–20nm)tip to target surface distance.A high resolution (beyond diffraction limit)evanescent energy ﬁeld generates at the tip and decays exponentially with increasing distance.The nanometer distance between the tip and target ensures that the evanescent wave arrives at the target surface with sufﬁcient energy density.The patterned photo-resist is further treated by chemical etching,plasma etching or UV light radiation to create nano-scale patterns on the substrate.The technique was ﬁrst reported by Lo and Wang in 2001to demonstrate 128nm resolution fabrications [100].Sun and Legget from Shefﬁeld University,UK [172,173]selectively oxidized a strongly bound self-assembled nanolayer (SAM)photo resist on a gold substrate using the SNP technique (the terminology of SNP was ﬁrst proposed in 2002)followed by chemical etching to realise 20–55nm resolution in surface patterning.This is matching the resolution by electron beam lithography but without the use of a vacuum chamber.The technique was further developed by scientists at Singapore Data Storage Institute and National University of Singapore,using a frequency-doubled Ti:Sapphire femto-second laser at l =400nm,coupled into an NSOM ﬁbre probe to achieve 20mm resolution surface patterning on a UV photo resist (around 40–120nm thickness)spin coated on a Si substrate for data storage applications [21,56,93–95,217].The laser etched depth was 20–100nm.The tip/sample distance was regulated by a tuning-fork-based shear-force feedback.Typical writing speed is 8–12m m/s.In the coupled laser and NSOM nano-fabrication technique,the probe-to-sample distance is a critical parameter to control both the nano-feature size and shape.At a small probe diameter and probe-to-substrate distance,the NSOM overcomes the traditional far-ﬁeld diffraction limit and can be used to obtain sub-wavelength-size patterns.Fig.2shows an example of nano-line arrays created at different incident laser powers.In addition,higher writing speed leads to shorter exposure time and thus lower exposure dose,resulting in a narrower line width and shallower depth.Considering that there is a melting threshold of the NSOM tip metal coating,a low power (<1mW)laser source is typically used to avoid damaging theNSOM tip.For the photo-resist exposure process,exposure energy dose is another important parameter,which is decided by exposure UV light energy and exposure time.The high resolution of the SNP technique is comparable to electron beam lithography.Furthermore,as the nano-features can be fabricated in air,with a multi-NSOM ﬁbre tip design,parallel nanolithography can be realised for high speed surface nano-structuring.The drawbacks of the technique include the requirement of high precision nano-distance control between the ﬁbre tip and the target,and potential contamination or damage to the ﬁbre tip.If the target surface is rough (>50nm Rz)then it is difﬁcult to apply the technique for uniform pattern writing.A recent development has enabled a nano-second laser NSOM technique (200nm probe diameter)to be applied for direct fabrication of nano-scale features on Si without the use of subsequent photo or chemical etching [165].2.3.Nano ridge aperture (bowtie)beam transmission enhanced nano-fabricationThe amount of light transmission through a small aperture of an object depends on the aperture size,d a ,relative to the wavelength,l ,of the light source.For an aperture smaller than the laser wavelength,light transmission is restricted.For example,for a circular aperture,the transmission efﬁciency is on the order of (d a /l )4due to the optical diffraction effect [11].Researchers in Perdue University,USA,found that,with a speciﬁc aperture geometry such as a bowtie or H,high energy laser beams can be delivered through the aperture with much less attenuation than a circular aperture and the energy is sufﬁcient to produce nano-scale patterns on a surface through contact lithography [29,226].The enhancement was found to be due to near ﬁeld surface plasmonic effect [29,227].Fig.3a shows a typical bowtie aperture used for nano-fabrication.The aperture was made of atomic force microscope cantilever probe (Si 3N 4coated with an Al ﬁlm)with the gold coating removed from the back side and the bowtie geometry milled using a focused ion beam.The aperture had 180nm Â180nm outline dimension and a 30nm gap.When a laser beam of 800nm wavelength and 50fs pulse width at 1.5–7.9mW power passed through the aperture,lines with widths down to 62nm and 2nm depth were produced on a photoresist material at a scanning speed of 2.5m m/s as shown in Fig.3b.The distance between the bowtie aperture tip and the target surface was 30nm.The laser beam intensity at the tip of the bowtie aperture was found 39.8times that of the incoming beam due to plasmonic enhancement.As this phenom-enon only occurs at the near ﬁeld,some researchers also classify this technique as the NSOM based nano-fabrication.2.4.Optically trapped micro-sphere assisted nano-writing (OTAN)Scientists at Princeton University recently developed a laser nano-patterning technique based on laser tweezers [118].AFig.1.Illustration of the scope of thepaper.Fig.2.Nano-lines created by the coupled fs laser/NSOM SNP technique at different incident laser powers [55].L.Li et al./CIRP Annals -Manufacturing Technology 60(2011)735–755736transparent sphere (polystyrene)was held by a focused continuous wave laser beam (converted to a Bessel beam using an axicon lens)as in a typical laser tweezers setup in a liquid environment.At the same time,another pulsed laser (355nm wavelength,15nm pulse length,15nJ–8mJ pulse energy)passes through the sphere and produces a focused energy spot at the bottom of the sphere based on the near ﬁeld evanescence wave effect.By traversing the sphere over a surface,nano-scale patterns have been generated.Due to the balance of the laser beam radiation pressure with the electrostatic repulsion from the target surface [211],which develops due to ionic groups on the surfaces,the distance between the sphere and the target surface can be maintained constant even for a curved surface without any additional feedback control systems.Fig.4shows a typical process set up and an example of a nano-pattern fabricated using the technique.Arbitrary patterns with the line width around 100nm were demonstrated with 15nm feature size variation.The scientists at the Princeton group further developed the technique by splitting the sphere trapping beam into multiple beams using beam splitters to hold and move several micro-spheres (0.76–3m m diameters)simultaneously,while ﬁring a pulsed power beam to them.Such a system enabled them to write a number of parallel nano-patterns on a polyimide ﬁlm coated on a glass substrate [118].An advantage of the technique compared with other near ﬁeld direct writing techniques is that for OTAN there is no need for distance control and it can work on rough surfaces [186].A limitation of the technique is that it can only operate in a liquid environment.2.5.Femtosecond (fs)laser direct writingThe process involved in the formation of nano-scale features by fs lasers is different from the conventional lasers.In fs laserinteraction with materials,the laser interaction time (10À15–10À13s)is shorter than the time for electrons to pass the energy to the lattice (around 10À11s).As a result,the material remains cool while absorbing the laser energy.The use of ultra-short pulse durations of the fs laser pulses restricts the heat diffusion,and improves surface roughness,and also minimizes damage to the adjacent areas.Due to the above mentioned advantages,fs lasers are used for writing couplers [120],waveguide ampliﬁers [162],diffraction gratings and memory bits [24].To achieve nano-scale resolution,the tip of Gaussian beam is used (setting the laser ﬂuence low enough so that only the tip of laser beam is above the ablation or phase change threshold of the material).In this way,far ﬁeld laser nano-fabrication beyond diffraction limit can be realised.Typical pulse energy of fs laser nano-fabrication is between 0.1and 100m J and power densities above 1TW/cm 2.Tight focusing of the light by a high NA telecentric lens is essential for fs laser nanofabrication.Another advantage of telecentric lens is that every successive scanning beam is parallel to the optical axis.Due to this,the beam is incident normally on the entire surface area and symmetrical features can thus be written.Minimal variation in laser focus energy and accuracy of focal spot/sample scanning ensure fabrication with high precision.The charge-coupled device (CCD)camera assists in optical adjustment and in situ fabrication monitoring [236].Three critical factors that govern the fs laser writing mechanism are chemical nonlinearity,material nonlinearity,and optical nonlinearity.When a high power density from a fs laser is incident on a target surface,photons are absorbed by either one-photon absorption (OPA),two-photon absorption (TPA),or the multi-photon absorption (MPA).Photon absorption caused by fs-laser beam irradiation leads to different processes such as ionization,electron excitation,and phase transitions.The electrons are agitated and their oscillatory energy is converted into thermal energy of the plasma by collisions with ions by the linear damping mechanism referred to as inverse Bremsstrahlung heating .This raises the temperature and the laser energy is absorbed by the plasma by OPA.These phenomena can occur only in a localized region around the focal point due to the high peak intensity.The separation between the high energetic electron cloud and the positively charged ions in the bulk causes a high voltage (known as Dember voltage)close to the surface which results in the repelling of materials in a process known as Coulomb Explosion.For this reason,the fs laser processing is also termed as cold laser processing and it is possible to write features even in transparent materials [109,121,126].In summary,the formation of nano-features is attributed to the interaction between the fs laser beam and laser-induced electron plasma and matter [159].Two photon absorption mechanisms are illustrated in Fig.5[84].In the ﬁgure,S 0,S 1,and S 2are ground state,one-photon allowed and two-photon allowed excited states,respectively.The incident light frequencies are v 1and v 2while the ﬂuorescent emission frequency is v 3.It should be noted that in standard optical lithography,the materials respond to light excitation to the ﬁrst order effect.For TPA and MPA in fs laser writing,the response is limited to two and higher orders and the square light intensity is also narrower than a linear one.This makes the photon energy of TPA less than thatofFig. 3.Nano bowtie aperture (a)and nano surface patterns produced by transmitting a laser beam through it (b)[29].Fig.4.Illustration of laser trapped micro-sphere nano-patterning.(a)Experimental set up and (b)an example of optically trapped micro-sphere nano writing.The scale bars on the larger picture and the zoomed-in pictures are 2m m and 250nm,respectively [118].Fig. 5.Schematic energy diagram of a TPA process [84](reproduced with permission from Elsevier).L.Li et al./CIRP Annals -Manufacturing Technology 60(2011)735–755737OPA.As a consequence,the volume involved in beam-material interaction reduces and this leads to better resolution in writing the features.The volume in which this energy is absorbed is less than the third order of the laser wavelength (l 3)and hence high spatial resolution of the writing process ( 100nm)beyond the optical diffraction limit is possible [176].For nanoscale writing,it is essential that the laser energy penetrates into the bulk material without any signiﬁcant losses.For this purpose,a light source with near-infrared wavelength (such as l =800nm)is selected for surface,sub-surface and in-bulk writing.Due to the high transient power density,fs lasers can excite a wide range of materials and induce irreversible processes such as photopolymerisation,photoisomerization,and photoreduction.Femtosecond lasers have numerous advantages over longer pulsed lasers for materials processing [179,195–197]due to which they have been used for writing nano-features in a wide variety of materials such as metals,polymers and ceramics.Examples of the material,and dimensions of the nanofeatures ( 100nm)written by fs lasers are presented in Table 1and Fig.6.2.6.Micro-lens array for fabricating periodic nano-structuresPeriodic nanostructures are useful for plasmonic structures,photonic crystals,high density data storage,miniaturized radio frequency (RF)oscillators and optical gratings.Micro-lens array (MLA)lithography is a laser-based technique being developed for rapid fabrication of large-scale periodic nanostructures.MLA consists of a series of miniaturized lenses of identical sizes and focal lengths,typically arranged hexagonally or squarely packed.When used in a typical optical system,an MLA can focus an incident light beam to form a series of parallel light spots in the focal plane.Downscaling of the diameter,D ,and the focal length,f ,of a lens improves its optical performance [52].For a ﬁxed F number F =f /D ,the diffraction-limited resolution is given by d x %l F 2which is independent of the lens scale.However,the wave aberrations which describe the deviation of the actual wave front from a perfect spherical wave front,are less for smaller lenses for the same F number and wavelength.On the other hand,small lenses have a shorter focal length [200].The early studies of micro-lens array based photolithography were for the manufacturing of periodic micro-scale features [58,200].As the micro-lens array production technology improves,the size of micro-lenses get smaller and so are the feature sizes.For example,scientists at Singapore Data Storage Institute and National University of Singapore used an 800nm wavelength,100fs laser to irradiate a 30nm-thick GeSbTe layer sputtered onto a polycarbonate substrate.It created thousands of ﬁeld emission transistor structures in a few minutes with a gate line width of 200nm.In addition,using an alkaline solution to etch the material after laser radiation,nanostructures down to 55nm on the thin ﬁlm were produced [96].To achieve further reduction in feature sizes,they manufactured a micro lens array on a quartz substrate with a diameter and pitch of 1m m each,which consists of 2500Â2500(6.25million)lenses covering an area of 5mm Â5mm.UV light-sensitive photoresist irradiated by a 248nm wavelength,23ns pulse width KrF excimer laser through the MLA created nano-dots as small as 78nm in diameter,at a resolution of one-third the operating wavelength [92].Fig.7shows an example of periodic patterns produced by a micro-lens array system.A critical requirement of the micro-lens array lithography fabrication technology is that the lens must be horizontal to the target surface within the entire radiated area to ensure the beams are vertical to the surface so that the feature sizes are identical.The lens to target surface is also needed to be controlled precisely.For a non-ﬂat surface,it is difﬁcult to fabricate uniform nano-structures using this technique.2.7.Far ﬁeld laser interference lithography (LIL)Laser-interference lithography is a large-area,maskless,and noncontact nanofabrication technique suitable for repeatable structures such as periodic lines and 2D shapes.It is based on the interference of two or more coherent light beams that form a horizontal standing-wave pattern.The minimum spacing,d L ,between the lines is determined by the laser wavelength,l ,and angle,a ,between the laser beams as in:d L ¼l2n sin ða =2Þ(2)This interference pattern is then recorded on the exposed ser-interference lithography can be used to fabricate micro-and nano-surface structures in large areas.By overlapping exposures at different angles,various patterns (e.g.circular,square,and hexagonal geometry)can be produced.Table 1Examples of nano-features written by fs lasers.Base materialNano-featuresReferences Copper thin ﬁlm Pits of 75nm[195]Amorphous silicaGratings of 15nm width[57]Urethane acrylate resin,SCR 500Wires of 65nm lateral width at central portion [177]Glass Hillocks of 40–70nm height [193,194]TeO 2Voids of 30nm width [158]SiO 2Stripes of 20nm width[159]Bulk aluminium Irregular nanoentities with average size of 100nm [170]Lithium niobateThick layer of 100nm[24,109,110,169]CVD diamond surfaceRipples with periodicity of 50–100nm[136]AAO matrix (Au deposited into anodized aluminium oxide)Nanorods of diameter 20–40nm and length of $50nm [147]Commercial resin,SCR 500Lines with width of 23nm[180]Gallium nitride Craters of depth varying from 26to 40nm[126]Silica glass Wires of width of 15nm and holes of 20nm diameter [70]TiO 2Ripples with depth of 100nm[23]Fig.6.Nanofeatures developed in (a)amorphous silica [57](reproduced with permission from Elsevier),(b)urethane acrylate resin,SCR 500[176](reproduced with permission from the Optical Society of America),(c)commercial resin,SCR 500[180](reproduced with permission from American Institute of Physics),(d)glass [193],(e)TeO 2[158],(f)photoresist thin ﬁlm [94],(g)CVD diamond surface [136](reproduced with permission from American Institute of Physics).L.Li et al./CIRP Annals -Manufacturing Technology 60(2011)735–755738Examples include nano-cone arrays on Ni–Cr alloy (Fig.8)and Au/Ag bi-metallic plasmonic structures on quartz ing this approach,after only a few minutes of UV light exposure,followed by photoresist development and chemical etching,periodic nano-lines and nano-dot arrays can be created over a centimetre scale area.To further improve the resolution,immersion laser interference lithography was developed at Max-Planck Institute of Micro-structure Physics,Germany [18].This is to increase ‘‘n ’’in Eq.(2)by introducing a Littrow prism and water as the immersion liquid.In this case,n =1.51.Line patters with a period less than 100nm and a width of 45nm were demonstrated with a 244nm wavelength laser (Fig.9).Another way of increasing the resolution is by reducing the laser wavelength,such as the use of an extreme ultraviolet laser source (e.g.an A +8laser at a 46.9nm wavelength).A great advantage of this method is the increase of ablation depth to over 120nm on Si based photo-resist [112].By combining an EUV laser and Lloyd’s mirror interferometer (Fig.10),nanostructures of 60nm feature size were produced on PMMA (Fig.11).The ablation depth is 20–30nm.Also lines with 95nm width were produced on Au substrates using the technique by the same group.A drawback of the EUV technology is that the process will need a vacuum chamber to operate due to the use of EUV system which can easily ionize gases if it is operated in non-vacuum conditions.2.8.Near ﬁeld interference lithographyNear ﬁeld interference lithography is based on evanescent (non-propagating)wave or surface plasmon wave interferences.The purpose is to defeat the diffraction limit of the lasers to fabricate smaller nano-structures.Evanescent interferometric lithography (EIL)or evanescent near ﬁeld optical lithography (ENFOL),or evanescent wave interference lithography (EWIL)was ﬁrst demonstrated using a mercury arc lamp in 1999by Blackie et al.at University of Canterbury,New Zealand [3,14].Laser based evanescent wave near ﬁeld lithography using total internal reﬂection (TIR)was ﬁrst reported in 2006by Martinez-Anton of University Complutense Madrid,Spain [115].A typical TIR conﬁguration is shown in Fig.12with two intersecting beams at an angle to enable the total reﬂection to occur to create periodic evanescent waves.Theprismrge area micro/nanostructures fabricated by laser MLA [92].Fig.8.A nano-cone structure fabricated by laser interference lithography (height 40nm and width 30nm)[152].Fig.9.Photoresist patterns created by immersion laser interference lithography.(a)Low magniﬁcation and (b)high magniﬁcation images of the pattern;the width of the resist lines is 43.4nm.(c)Silver lines after evaporation of 15nm Ag and lift-off [18].Fig.10.A typical optical conﬁguration for Lloyd’s mirror interferometer laser interference lithography,where u =a /2[112].Fig.12.Illustration of a typical TIR optical conﬁguration to generated evanescent waves through interference of tow intersecting beams [115].Fig.11.Two dimensional nano patterns on PMMA produced by EUV laser interference lithography using Lloyd’s mirror interferometer with two exposures at different angles,(a)dots with 60nm FWHM feature size and a period of 150nm,(b)regular shapes dots,(c)elongated dots [112].L.Li et al./CIRP Annals -Manufacturing Technology 60(2011)735–755739was irradiated with split 405nm wavelength laser beams.Periodic surface relief gratings of around 100nm period were produced on photoresists using this technique [115].More complicated 2D nano-structures can be fabricated using multiple (more than 2)beam interference through polarization tuning,based on TIR evanescence wave near ﬁeld lithography,as demonstrated by Chua and Murukeshan [22].The photoresist in optical contact with the TIR prism (rectangular)has a lower refractive index than the prism.Patterns of 70nm feature size had been produced using this method (Fig.13).A drawback of this method is that the depth is shallow due to the non-propagating nature of the evanescent wave.The energy transmission through the masks is also very low.Surface Plasmon Interference Lithography (SPIL)is another near ﬁeld lithographic technique developed recently to improve energy transmission and fabrication depth over the evanescent wave lithography.It is based on energy ﬁeld enhancement by the interaction of light with surface Plasmon (SP,collective electron oscillation)waves induced around the nano-scale metallic struc-tures and a dielectric interface.If the metallic mask is very thin (e.g.50nm),surface Plasmon waves can be generated on both surfaces,even the structures are not through the full thickness of the metallic ﬁlm.The enhancement,through the coupling between the surface plasma waves and the evanescent waves,can be several orders of magnitude in intensity compared with the incoming beam.The wavelength of the excited surface Plasmon wave is shorter than that of the exciting laser at the same frequency.Therefore higherresolution is expected.The wavelength of the exciting laser,l (i ,j ),needs to match the materials and the structures of the mask.Their relationships can be found from [168]:l ði ;j Þ¼aﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃi 2þj 2q ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃe d e m e d þe mr (3)where a is the metallic mask periodic nanostructure period,e a and e m are the dielectric constants of the mask metal and the surrounding dielectric medium,respectively and i ,j are mode indices.For example,a UV light can excite surface Plasmon waves on Al with a nanostructure period of 220nm.A green or blue light can excite surface Plasmon waves on a silver mask with a period of 400–500nm.A larger period allows longer exciting wavelengths.The SPIL technique for the fabrication of periodic surface nanostructures was ﬁrst reported independently by two separate groups (University of California in USA and RIKEN in Japan)in 2004[103,168]using an Al or a silver mask.An example of a typical conﬁguration for the SPIL technique is shown in Fig.14.For an 80nm thick Al mask of 20nm diameter holes and 220nm period (fabricated using a focused ion beam)and 30nm spacer (PMMA)and irradiated with an arc lamp with a peak intensity at 365nm,90nm periodic structures were produced on a photoresist [168].The RIKEN group fabricated periodic 100nm lines using a silver mask radiated with a 436nm light.They termed the method as SPRINT (Surface Plasmon Resonance Interference Nanolithography Technique)and proposed to use imperforated metallic marks which have corrugated surfaces on both sides of the metallic mask.The illuminated side collects the light and induces the SP waves on the other side of the target material through SP coupling.Sreekanth et al.at Nanyang Technological University of Singapore compared standard far ﬁeld laser interference lithography,near ﬁeld evanescent wave lithography and the SPLIT techniques in nano fabrication of period surface structures [167].They found that that the SPIL technique can produce deeper features than the evanescent wave lithography technique and both near ﬁeld lithography techniques have a better resolution than the far ﬁeld lithography technique.Fig.15shows an example of periodic dot arrays fabricated on a Si wafer using the SPIL technique with a UV Argon ion laser at 364nm wavelength,which has a 82Æ11nm feature size,164Æ11nm period and an average height of 180nm [167].2.9.Contact particle lens array nano-fabrication (CPLA)This technique is based on the use of transparent micro spherical particles spread onto the target surface byself-assemblyFig.13.Two dimensional features fabricated using evanescent wave interference lithography generated by TIR of four p-polarized incident beams.(a)Theoretical inverse positional photoresist development rate at the interface between the prism and photoresist,(b)SEM image of hexagonal arrayed 2D features.Inset:Enlarged region showing the peak (P),valley (V)and saddle (S)regions (top right),(c)AFM image of the nano-structures [22].Fig.14.A typical process conﬁguration for SPIL and an optical mask,(A)schematic drawing of the SPIL set up and (B)an Al mask for the SPIL experiment (fabricated using FIB)with a hole size of 160nm and a period of 500nm [168].L.Li et al./CIRP Annals -Manufacturing Technology 60(2011)735–755740。

Close-Range Photogrammetry基于网格的测量算法说明书

The Algorithm of Measuring in Close-Range Photogrammetry based on GridWanli Xu, Zhun Liu, Huiyu NieDepartment of Information Engineering Academy of Armored Force EngineeringBeijing,100072,ChinaAbstract —The Algorithm of Measuring in Close-Range Photogrammetry based on Grid [Purpose] Due to the existence of various error sources in the close-range photogrammetry, the traditional photogrammetry algorithm cannot completely eliminate system error. The measurement precision often cannot reach the requirement and the calculation process is complicated. In order to solve this problem , a new measuring algorithm called grid measuring algorithm is presented in this papers. [Method]We structures an ideal grid measuring space according to image point of the fixed point. Then the interested object points are mapped to the grid measuring space by the image points. We can get the position by fusing the value according to the distance to the nodes.For illustration,a photographic example is utilized to show the feasibility of the grid measuring algorithm.[Results] The experimental results show that the error of grid measuring algorithm is controlled within half pixels. [Conclusions]The positioning precision of this algorithm is obviously superior to the traditional algorithm and the calculation is simple.Keywords- close-range photogrammetry; grid measuring space; grid measuring algorithmI. I NTRODUCTIONPhotogrammetry is to calculate the position of the object point according to its image point by photographing. Close-range photogrammetry is the photogrammetry that the distance is close. If the algorithm of close-range photogrammetry is appropriate, the measurement error couldbe controlled within 0.1 mm[1]. So close-rangephotogrammetry has high positioning accuracy and it can be used for aerospace workpiece machining control as well as toother measuring instrument inspection correction. It has highpractical value. But there are various error sources such as the distinction of focal distances of the two cameras, the biasof cameras, the errors of fixed points and so on in the close-range photogrammetry. The positioning precision is affected directly. The traditional photogrammetry algorithms usually calculate the parameters and correct them one by one. But it cannot completely eliminate system error and the calculation process is complicated. So the research of photogrammetry algorithm is the key point to improve the positioningprecision. Because the distance of close-range photogrammetry is close, the controlling points and objectpoints could be fixed by manual work. It is beneficial to eliminate system error[2].II. P RINCIPLE O F P HOTOGRAMMETRY Assuming that the coordinate system is S1-XYZ,it is shown in Figure 1. Its origin point is S1 which is the focal point of left camera and its Y axis is S1O1 which is the main optical axis of left camera and its Z axis is the plumb line passing through S1.The connecting line S1S2that links the focal points of two cameras is the baseline B. The focal distance of camera is f. Photo is behind focal point in practice. We can evolve photo before focal point as shown in Figure 1.Figure 1. Coordinate system Assuming that the coordinate of object point A is (X A ,Y A ,Z A ), the coordinates of corresponding image points inleft and right photos are (x 0,f ,z 0) and (x 1,f ,z 0) . Because the object point, the image point and the focal point of camera are on the same line, we can get two equations of straightlines that are followed as below[3][4]: 00000110A A AA A A x x z z y f X x Y f Z z z z x x y f X x Y f Z z −−−⎧==⎪−−−⎪⎨−−−⎪==⎪−−−⎩As the focal points of two cameras are on the lines above-mentioned and their coordinates are (0,0,0),(B ,0,0).we can get the results followed as below[5]: 000010A AA A A YB X x x B p fB Y f B p YB Z z z B p f p x x⎧==⎪−⎪⎪=⎪−⎨⎪==⎪−⎪⎪=−⎩ (1)A line segment that its length is L on the object plane which is parallel to the photo plane and its distance far away from the focal point is Y has the relation with the corresponding pixel segment that its length is l in the photo as below:Y f L l = (2)We can get the length of base line by equations (1) and (2) as below:)1B p l L =− (3)In order to calculate the focal distance of camera f, we take steps as below. Assuming that there is a board that its distance far away from the focal point is Yi, we call it as i-th plane. Then move the board to the plane called j-th plane that its distance far away from the focal point is Yj along the main optical axis. Find two sign points that its distance is L in the i-th plane. Calculate the pixels li that the two sign points space. Then find the two corresponding sign points in the j-th plane and calculate the pixels lj. So the lengths of the two sign points in the i-th plane and in the j-th plane are li*dx,lj*dx, where dx is the length of every pixel. According to equation (2), we know that,()i i Y f L l dx =×(4))j j Y f L l dx =× (5)And (5)-(4), we can obtain the focal distance of the camera.11()j i j i Y Y f L l dx l dx−=×−×× (6)III. G RID M EASURING A LGORITHMWe structure a grid measuring space. That is to say, we structure a ideal grid measuring space according to the image points of the sign points. And then map the object point to the grid measuring space through its corresponding image point. At last, we can get the position by fusing the value according to the distance to the nodes of the grid net. We illustrate it through an example. Firstly, we structure a grid measuring plane. As is shown in Figure 2, there is an auxiliary glass board that its area is 420 mm × 420 mm. There is a sign point every 20 mm interval. The sign points structure a grid net. The planewhere the glass board locates is the 0-th plane. Then take out the sign points of the row that close to the main optical axis and calculate the interval pixels l0 that every two sign pointsspace according to the first sign point and the last sign point. Make the first sign point that close to the main optical axis as the start point and l0 as the interval to structure the gridmeasuring plane.Figure 2. Experiment environmentThen, we structure the grid measuring space. Accordingto equation (4), the horizontal distance of an arbitrary object point to the main point L has the relation with its pixelcoordinate i x: ii Y x dx L f ××=×, 0,1,2,...,i N =. Sowe can get the equation as below:i i j j Y x Y x ×=×,,0,1,2,...,i j N=(7)According to equation (7), if we know the distances of an arbitrary plane and 0-th plane far away from the focal point and the horizontal pixel coordinate, we can get the horizontal pixel coordinate in the plane above-mentioned. So we can obtain the other plane through 0-th plane. At last we get the grid measuring space.After structuring the grid measuring space, map the image points to the grid measuring space. Map the sign point O ij that locates at the i -th row and j -th column in the photo, ,1,2...,21i j =, to the sign point O ij that locates at the i -th row and j -th column in the grid measuring space. Map other points in the photo to the grid measuring space by fusing the value according to the distance to the nodes of the grid net as below:11()/()()/()ij ij ij ij ij ij i j ij X X x x l x x Z Z z z l z z ++=+−×−=+−×−Where (x ,z ) is the coordinate of the image point obetween the image points1111,,,ij ij i j i j o o o o ++++,11(,),(,),ij ij ij ij x z x z ++111111(,),(,)i j i j i j i j x z x z ++++++are the coordinates of the four image points in the photo. (,)ij ij X Z is the coordinate of the point which locates at the i -th row and j -th column in thegrid measuring space and l is the pixel interval. Then (,)X Z is the coordinate that the object point o maps to the gridmeasuring space. At last, we can calculate the position of the object point o according to equation (1).IV.E XPERIMENTWe measure a standard instrument that is in common use international in the lab of as shown in Figure 2. The standard instrument demarcates three distances between the circles of balls. (see Table I )Locate the standard instrument at ten different positions in the same distance far away from the camera and then photograph it. We photographed the glass board and the standard instrument at 0-th plane and 1-th plane with the left and right cameras. The pixel area of photo is 8176 × 6132. The length of every pixel is 0.00599315 mm.According to equation (6), we can calculate the focal distance of camera is 79.3019 mm.Map the circles of balls to the grid measuring space and then calculate the distances between the circles of balls shown in Table I.TABLE I. TABLEI.EXPERIMENT RESULTSMarkedDistance150.0034 300.0038 99.9909 Position 1 150.022905 299.985872 100.081973Position 2 150.024882 299.98099 100.013289Position 3 150.131724 300.086703 100.119358Position 4 150.101204 300.011683 100.068886Position 5 150.038428 299.991265 100.162784Position 6 150.088656 299.942022 100.075656Position 7 149.955386 300.026163 100.139414Position 8 150.077643 299.941602 99.904372Position 9 149.921781 299.920793 100.051582Position 10 150.080424 299.957109 100.036558Average 150.044303 299.984420 100.065387Error0.0409 0.0194 0.0745Standard Deviation 0.065871 0.048801 0.072979The average is the average of distances of the circles ofthe balls at ten different positions and the standard deviationis the standard deviation of distances of the circles of theballs at ten different positions. The error is the deviationbetween the average and the marked distance. According tothe distance of the standard instrument far away from thecamera and the focal distance of camera, we can concludethat the error of grid measuring algorithm is controlledwithin half pixels.V.S UMMARYThis paper presents a new measuring algorithmcalled grid measuring algorithm. It structures an ideal gridmeasuring space according to image point of the fixed point.Then the interested object points are mapped to the gridmeasuring space by the image points. We can get theposition by fusing the value according to the distance to thenodes. The positioning precision of this algorithm isobviously superior to the traditional algorithm and thecalculation is simple. The experimental results show that theerror of grid measuring algorithm is controlled within halfpixels.R EFERENCES[1]Junjian Lin, Guihua Chang. Photogrammetry. Beijing:NationalDefence Industry Press,2006.[2]Zuxun Zhang, Jianqing Zhang. Digital Photometry. Wuhan:WuhanUniversity Press,1997.[3]Ying Chen. Remote Sensing Image Digital Photogrammetry. TongjiUniversity Press,2003.[4]Zhoucheng Li. Intelligent Image Processing Technology.Beijing:Electronic Industry Press,2004.[5]Liangzheng Xia. Digital Image Processing. Southeast UniversityPress,1999.。

Proveo 8 with built-in EnFocus OCT Ophthalmic Micr

Physical Features
Workstation Operating System Removable scan head
OCT scanner dimensions
Scan head weight
64-bit, Windows 10
Yes Scan head: 6 cm (h) x 10 cm (od) Relay arm: 28 cm (h) x 4 cm (od) Scan assembly: 21 cm (h) x 17.5 cm (w) x 39 cm (l) 2.6 kg (5.7 lbs)
MC-0001676 · 05.11.2020 · EN · Copyright © 2020 Leica Microsystems (Schweiz) AG. All rights reserved. Subject to modifications. LEICA and the Leica Logo are registered trademarks of Leica Microsystems IR GmbH. BIOM and BIOM 5 are brands of OCULUS, Inc.
Proveo 8 is a class I surgical microscope
EnFocus intraoperative OCT is a class IIa medical device 0123
Leica Microsystems (Schweiz) AG Max Schmidheiny-Strasse 201 9435 Heerbrugg, Switzerland
OCT image overlay with microscope view in eyepiece for Proveo 8 (with optional DI C800) Multi-touch gesture control on 27” touch screen monitor, wireless keyboard, microscope footswitch, and handles Integrated OCT footswitch control for Proveo 8 Support additional monitor display 1x DVI (replicate primary monitor) 1x HDMI (replicate any OCT screen: Quad, 50/50, camera only) 1x HD-SDI, 1x Composite (replicate camera only) Cross-hair, rectangular, circular, and linear Fully customizable scan presets based on procedure type (Cornea, Retina BIOM, Retina Flat Lens) Max scan density: 1000 A-scan x 1000 B-scan

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Close-Range Photogrammetry基于网格的测量算法说明书

Proveo 8 with built-in EnFocus OCT Ophthalmic Micr

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