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英文作文articleTitle: The Impact of Technology on Education。

In today's rapidly evolving world, technology plays an increasingly significant role in every aspect of our lives, including education. The integration of technology into education has brought about both positive and negative impacts, shaping the way students learn and educators teach. This article explores the various ways in which technology influences education and discusses its implications for the future.First and foremost, technology has revolutionized the way information is accessed and disseminated. With the internet and digital devices, students now have access to a vast amount of information at their fingertips. They can easily conduct research, explore diverse perspectives, and engage with multimedia resources to enhance their learning experience. This accessibility to information has democratized education, breaking down barriers to learningand empowering students from all backgrounds to pursue knowledge.Moreover, technology has transformed the traditional classroom environment. Interactive whiteboards, educational apps, and online platforms have become commonplace, providing educators with tools to create dynamic and engaging lessons. These digital resources cater todifferent learning styles and allow for personalized instruction, enabling students to learn at their own pace and according to their individual needs. Additionally, technology facilitates collaboration among students through online forums, video conferencing, and shared documents, fostering a sense of community and enhancing communication skills.Furthermore, technology has opened up new avenues for creativity and innovation in education. Students can now utilize multimedia tools to express their ideas, create multimedia presentations, and develop digital projects. Virtual reality (VR) and augmented reality (AR) technologies offer immersive learning experiences, allowingstudents to explore virtual environments and simulate real-world scenarios. These innovative approaches not only make learning more engaging but also cultivate critical thinking, problem-solving, and digital literacy skills essential for success in the 21st century.However, despite its numerous benefits, the widespread use of technology in education also poses challenges and concerns. One major issue is the digital divide, whichrefers to the gap between those who have access to technology and those who do not. Socioeconomic disparities and inadequate infrastructure can hinder access to digital devices and high-speed internet, depriving certain students of the opportunities afforded by technology. Bridging this divide requires concerted efforts from policymakers, educators, and technology providers to ensure equitable access to technology for all students.Additionally, the overreliance on technology in education raises concerns about its potential drawbacks. Excessive screen time and digital distractions can impede students' focus and concentration, leading to decreasedacademic performance and impaired social skills. Moreover, the proliferation of online resources raises questions about the quality and credibility of information available to students. Educators must teach students how tocritically evaluate sources and discern fact from fiction in an age of information overload.In conclusion, technology has undoubtedly reshaped the landscape of education, offering unprecedentedopportunities for learning and innovation. From enhancing access to information to fostering collaboration and creativity, technology has the potential to revolutionize education for the better. However, realizing this potential requires addressing challenges such as the digital divide and mitigating the risks associated with overreliance on technology. By harnessing the power of technology responsibly, educators can empower students to thrive in a digital age and prepare them for the challenges of the future.。

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annual volatilities of spot prices were 163.91% for copper, 119.05% for chromium, 168.24% for uranium, 153.87% for zinc, and 44.46% for lead. These data show that increasingly more companies are being exposed to high risks in natural resources prices, implying that the stable supply of natural resources is very important for the national economy and for the survival of a company.
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C. Won / Energy 34 (2009) 1215–1224

pricing model which is both easy to apply and realistic in order to help ﬁrms’ investment decision-making.
There are two major competing procedures for evaluating risky projects in natural resources developments: one is decision analytic, based on traditional discounted cash ﬂow and stochastic dynamic programming (Fleten et al. [11], Smith and McCardle [27], Szklo et al. [28]) and the other is option pricing model (OPM) or contingent claims analysis, based on the no-arbitrage theory of ﬁnancial markets (Brennan and Schwartz [3], Ekern [9], Emhjellen and Alaouze [10], Laughton [18], Paddock et al. [22], Schwartz [25], Sezgen et al. [26]). In this paper, we develop a new pricing model of natural resources projects by applying contingent claim analysis in order to help ﬁrms evaluate the projects more accurately and easily. Our model is different from previous models in several respects. First, our model uses different assumptions about underlying variables and different methodology. For example, we treat both output prices and development costs as stochastic and derive a closed-form solution through Martingale framework. While most of the previous literature treats only output prices as stochastic (Brennan and Schwartz [3], Dixit [6], Gibson and Schwartz [14], Laughton [18], Paddock et al. [22], Pindyck [23], Schwartz [24, 25], Sezgen et al. [26]) and does costs as uncertain, we make our model more realistic by treating both output prices and development costs as stochastic processes, because development costs change over time depending upon the ﬂuctuations in materials and labor costs necessary for the developments. In addition, whereas we utilize Martingale principle to derive the pricing equation, other authors use different methods, such as an arbitrage argument through self-ﬁnancing (Brennan and Schwartz [3]), a dynamic decision tree (Smith and McCardle [27]), and a real option framework by considering various managerial ﬂexibility in the process of developments (Cortazar and Casassus [5], Fleten et al. [11], Laughton [18], Olsen and Stensland [21], Paddock et al. [22], Sezgen et al. [26], Szklo et al. [28]).

research article 中各部分的内容和作用

research article 中各部分的内容和作用
在Research Article中，通常包含以下几个部分，这些部分各自具有其特定的内容与作用：
1. 摘要（Abstract）：摘要部分通常简明扼要地概括了研究的主要内容、方法、结果和结论。

它为读者提供了关于研究的快速概览，帮助读者决定是否需要进一步阅读整篇文章。

2. 引言（Introduction）：引言部分详细介绍了研究的背景和目的，为理解后续的研究内容提供了背景信息。

它解释了为什么这个研究是重要的，以及预期的研究结果如何影响该领域的知识。

3. 方法（Methods）：这一部分详细描述了用于收集数据或执行实验的程序和过程。

它确保其他研究人员能够复制并验证研究结果。

4. 结果（Results）：结果部分呈现了通过研究获得的数据。

这些数据通常以图表、表格等形式呈现，以便读者可以直观地理解。

5. 讨论（Discussion）：在讨论部分，研究人员会解释研究结果的含义，将其与之前的研究进行比较，并探讨可能的解释和局限性。

此外，他们通常也会提出对未来研究的建议。

6. 结论（Conclusion）：结论部分总结了研究的主要发现，并强调这些发现对领域的影响和贡献。

它也指出了研究的局限性和未来可能的研究方向。

以上是Research Article中常见的各个部分的内容和作用。

具体组成部分可能会根据研究领域和期刊的要求有所不同。

在撰写Research Article时，遵循期刊的格式和结构要求是非常重要的。

报纸排版术语

报纸排版术语1. 标题（Headline）：报纸文章或新闻的标题，通常用于吸引读者的注意力。

2. 副标题（Subheadline）：文章标题下方的补充信息，用于进一步说明主题或引发兴趣。

3. 摘要（Summary）：文章的简短总结，用于提供读者文章的概要或引导读者进一步阅读。

4. 正文（Body Text）：文章的主要内容，一般分为段落，段落之间有空行分隔。

5. 引文（Quote）：直接引用他人的话语或观点，通常用引号引起来，并置于正文中。

6. 图片（Image）：插图或照片，为了更好地与相应的文章内容配合，图片通常会被放置在适当的位置，如在正文中间或与相关文章并排。

7. 图注（Caption）：图片的文字说明，用于解释图片内容或提供额外信息。

8. 副标题（Subhead）：辅助标题，用于分隔不同主题或段落，并使文章更易于阅读。

9. 纵横文字（Floating Text）：文字内容与图片并排，通常用于解释或说明图片内容。

10. 盒子（Box）：通常是一种用于突出或强调某个内容的边框或区域。

11. 脚注（Footnote）：文中以小字体给出的补充说明或者引用的资料来源。

12. 引语（Epigraph）：引用于文章开头的一段短文或作者的名言，用于引发读者的思考。

13. 页眉（Header）：出现在每个页面顶端的标题或版面标识，以便读者快速识别报纸或杂志。

14. 分栏（Columns）：将正文内容分为多个垂直排列的列，通常可以提高文字阅读的效果。

15. 页码（Page Number）：报纸或杂志的每一页都会标注唯一的数字或符号，用于读者寻找特定页面。

16. 导航（Navigation）：指导读者找到特定文章或内容的标志或链接，通常在每个版面上的侧边或底部有导航栏。

17. 装饰（Decoration）：用于美化报纸页面布局的装饰元素，如边框、线条、色块等。

18. 栏目（Section）：报纸或杂志中特定主题或内容分类的分区。

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Effect of shearing on crystallization behavior ofpoly(ethylene naphthalate)W.J.Yoon,H.S.Myung,B.C.Kim,S.S.Im *Department of Textile Engineering,Hanyang University,Haengdang,Seongdong,Seoul 133-791,South KoreaReceived 11August 1999;received in revised form 24September 1999;accepted 30September 1999AbstractThe effect of shear history on the isothermal crystallization behavior of poly(ethylene naphthalate)(PEN)was investigated by rheological and morphological measurements.Time sweep measurements of storage modulus (G H )and dynamic viscosity (h H )were carried out on the molten PEN by Advanced Rheometric Expansion System (ARES)in the parallel-plate geometry at several different temperatures and frequencies,followed by structural analysis by differential scanning calorimeter (DSC),X-ray diffractometer,and polarizing microscopy for the shear-induced crystallized PEN specimens in the ARES measurements.The rate of isothermal crystallization of PEN was notably affected by temperature,while the shear rate has an important effect on the structures of the resultant crystals.At a constant shear rate,the rate of crystallization by shear-induced structuring mechanism was increased with lowering temperature over the temperature range 230–250ЊC.The rate of crystallization was increased with increasing shear rate at a given temperature.An increase in shear rate increased both nucleation and number of crystallites.Further,it increased the content of the a -form crystal in the specimen.On the other hand,lower shear rate offered more favorable conditions for forming the b -form crystal.DSC analysis exhibited that the b -form crystal had higher melting temperature (T m )than the a -form crystal.The wide angle X-ray diffraction (WAXD)patterns also ascertained that higher content of the a -form crystal was produced in the PEN specimen crystallized at higher frequency.᭧2000Elsevier Science Ltd.All rights reserved.Keywords :Poly(ethylene naphthalate);Rheology;Shear-induced crystallization1.IntroductionShear-induced structural changes in polymeric materials take an increasing interest in the ﬁeld of polymer proces-sing.In real polymer processing very complex deformation histories are involved,which can inﬂuence ultimate proper-ties of plastics.Recent advances in experimental techniques that allow in situ measurements of materials under deforma-tion have escalated research in this subject area.It has been known for a long time that ﬂow stress have accelerating effect on the crystallization of semi-crystalline polymers [1–6].It is supposed that the application of a shear stress to a polymer melt should lead to formation of orientation and reduce the entropy of the melt,which results in a higher melting temperature and,hence,lead to an increased super-cooling [3,7].Several experiments have been described in the literature where attempts were made to quantify the shear stress-induced crystallization in molten semi-crystal-line polymers such as polypropylene [3,8,9],polyethylene oxide [10],polypropylene [11–13],and polybutene-1[3,14].Some investigators used rotational viscometers andmeasured either the volume change [15]or the number of nuclei formed during shearing [11,14].The polymers enum-erated above are apt to process because of low melting point and viscosity.On the other hand,PEN has good thermal and mechanical properties and is being used as engineering plastics.PEN is reported to have two different triclinic crystalline structures,a -form and b -form crystals.Of two crystal forms,the b -form crystal is known to be more stable than the a -form.The effect of crystallization temperature on the resultant crystal structure is well recognized;lower temperature favors formation of the a -form crystal.The critical temperature is reported about 230ЊC.However,the effect of shear history on the crystal structure of PEN has not been reported.In this study,the shear-induced crystallization behavior of PEN was investigated on the rheological basis.The effect of shear history on the crystalline structure was also discussed in terms of thermal and morphological properties.2.Experimental 2.1.MaterialThe PEN tested was a commercially available gradePolymer 41(2000)4933–49420032-3861/00/$-see front matter ᭧2000Elsevier Science Ltd.All rights reserved.PII:S0032-3861(99)00703-X*Corresponding author.Tel.:ϩ82-2-2292-0495;fax:ϩ82-2-2297-5859.E-mail address:imss007@email.hanyang.ac.kr (S.S.Im).supplied by Kolon Group in South Korea.The inherent viscosity,0.344dl/g was determined in a mixture of triﬂuoroacetic acid and chloroform (1/3v/v%)with an Ubbelohde viscometer at 25^0:1ЊC :The polymer was dried in a vacuum oven at 120ЊC for 24h prior to use.2.2.Measurement of physical propertiesThe dynamic rheological properties were measured by ARES (Rheometric Scientiﬁcs)in the parallel plate geome-try.The plate diameter was 12.5mm,strain level was 5%,and gap between the plates was 1mm.The PEN chips were melted at 300ЊC.The initial gap was set to a value equiva-lent to ﬁnal gap plus 50m m.The excess sample squeezed out by reducing the gap was carefully trimmed off.The value was reset to the ﬁnal gap value,1mm.To remove the residual stress the newly set PEN specimen was relaxed for about 5min at the temperature in nitrogen atmosphere,then cooled to the predetermined temperature for rheologi-cal measurements.A time-sweep experiment was continued for the specimen till the G H reached the ceiling value of the apparatus.After ARES measurement,the molten PEN sample was detached from the plates for measuring other properties such as thermal and morphological properties by DSC,X-ray diffractometer and polarizing optical micro-scopy.Thermal properties were measured by Perkin–Elmer DSC-7over the temperature 50–300ЊC at the heating rate of 10ЊC/min under nitrogen purge.The isothermalcrystallization experiment was performed by two different methods.Firstly,the PEN sample was heated to 300ЊC at the heating rate of 200ЊC/min,and held for about 5min,then they were cooled to the preset temperature to bring about the isothermal crystallization for same time required in ARES experiment.Secondly,the PEN chips were melted at 300ЊC between two slide glasses for 5min on the hot stage.They were moved to an oil bath very quickly and isothermally crystallized at 230,240,and 250ЊC for 4,10,and 24h,respectively.Wide angle X-ray diffraction patterns of the isothermally crystallized PEN specimen in the oil bath and ARES were obtained by X-ray diffractometer (Rigaku Denki)with Ni-ﬁltered CuK a radiation at 35kV and 35mA.Morphology of quiescent and shear-induced crystallized PEN specimen was observed by polarized microscopy (Nikon HFX-IIA).The spherulite structure was observed by microtoming the specimen.3.Results and discussionIn the plot of G H and h H versus time at a given frequency for a polymer,the two parameters may give information on the change in physicochemical properties of the polymer.For thermally sensitive polymer melts,an irreversible decrease of viscosity with time at a constant shear rate suggests the possibility of thermal degradation of polymer molecules,whereas an irreversible increase of viscosityW.J.Yoon et al./Polymer 41(2000)4933–49424934Fig.1.Variation of G H with time for PEN melt at 240ЊC at three different frequencies.with time indicates the possibility of chemical crosslinkingbetween polymer molecules.Both thermal degradation andchemical crosslinking show irreversibility in the rheologicalresponses.On the other hand,a reversible change in G H and h H with time at a constant frequency may be caused by changing in the physical state of the polymer melts.A typi-cal example of the physical change is the isothermal crystal-lization.As the crystallites grow to larger sized spheruliteswithin the PEN melt through nucleation and growth,thehomogeneous melt system changes to the heterogeneoussystem.Thus the G H and h H increase with the crystallization time.Figs.1and2show the variation of the G H and h H of PEN melt with time at240ЊC at three different shear rates(1,3, and5rad/s).At the early stage of experiment,both G H and h H are increased slowly,indicating an induction time for crystallization.The induction period is the stage when randomly entangled polymer chains transform to the regular aligned lattice.Because of topological obstruction of such entanglements,the polymer crystallization is extremely slow[16].However,an abrupt increase of both parameters follows in some minutes.This phenomenon can be ascribed to the formation of tiny crystals so-called crystallites prob-ably due to shear-induced crystallization.It can be easily imagined that the homogeneous PEN melt changes to a suspension system with proceeding crystallization,in which numerous crystallites are dispersed in the homo-geneous molten polymer matrix.The viscosity increases due to increasing the volume fraction of dispersed crystal-lites with progressing crystallization,which is also reportedby others[7,9,11,14,17].The ceiling value of G H is the same regardless of frequen-cies and temperatures whenﬁnishing crystallization asshown in Fig.1.On the other hand,the ceiling value of h H is gradually decreased with increasing the applied frequency as shown in Fig.2.This is attributable to pseudo-plasticity.That is,the heterogeneous system is expected toshow yield behavior[18].At low shear rates the hetero-geneous systems exhibit very high viscosity,and almostunbounded viscosity at zero shear rate.The viscosity,however,is rapidly decreased if the shear rate exceeds acritical value.Consequently,the ceiling viscosity at1rad/sis greater than at5rad/s.In addition,the ceiling value of h H shows a gradual decrease with time after having reached maximum as shown in Fig.2,which is more noticeable at the higher frequency.The gradual decrease of h H seems to result from the restructuring of the heterogeneous systems. That is,the viscosity is decreased with shearing on account of destruction of the orderedﬁller particle structure.The destruction of the pseudostructure ofﬁller particles is increased as shear rate is increased.Fig.2reﬂects this.It is also noted in Figs.1and2that the induction time forcrystallization is decreased as frequency is increased.Anapplication of shear stress to a polymer melt would giverise to two characteristic responses,orientation and slippageof polymer molecules.They are associated with theW.J.Yoon et al./Polymer41(2000)4933–49424935Fig.2.Variation of h H with time for PEN melt at240ЊC at three different frequencies.W.J.Yoon et al./Polymer41(2000)4933–49424936Fig.3.Variation of G H(A)and h H(B)for PEN melt at3rad/s at three different temperatures.W.J.Yoon et al./Polymer41(2000)4933–49424937Fig.4.DSC thermograms of PEN isothermally crystallized at(A)230ЊC,(B)240ЊC and(C)250ЊC at various frequencies.macroscopic phenomena of elasticity and ﬂow,respectively.That is,the oriented polymer molecule has fewer possible conformations than the unoriented one,which results in lower entropy.At the melting temperature,the free energy of the crystal equals the free energy of the melt as written by [3]T mD H f D S f H m ϪH cS m ϪS c1Hence,for an oriented melt,the ensuing reduction in entropy raises T m .Further,it increases the degree of super-cooling,accelerating the rate of crystallization.In general,higher shear rate gives better chance for orientation.Con-sequently,the induction time for cystallization is decreased with increasing shear rate.In Fig.3(A)and (B)shows that the annealing temperaturehas a profound effect on the nucleation and crystallization mechanism of PEN melts.The increase of G H and h H with annealing time represents the extent of crystallization of the melts with annealing time.Fig.3suggests that the number and growth rate of the nucleated crystallites is greater at 230ЊC than at 250ЊC.That is,both nucleation density and growth rate of crystallites are diminished with raising the annealing temperature.This stands to reason because the maximum rate of the homogeneous crystallization of PEN melts is observed in the vicinity of 215ЊC.The viscosity behavior of the PEN melt with crystalliza-tion in Fig.3may be accounted for by adopting the Mooney equation in a qualitative manner [19].ln h =h 1K E F 21ϪF 2=F m2W.J.Yoon et al./Polymer 41(2000)4933–49424938Fig.4.(continued )Table 1The values of T m H and T m HH of PEN with frequency (230,240and 250indicate temperature.(a)and (b)indicate v 0 a and v 0 b ;respectively (see Fig.6).1,3and 5indicate frequencyT m HT m HH T m HT m HH T m HT m HH PEN230(a)259.2272.1PEN240(a)266.7PEN250(a)270.1PEN230(b)264.1270.9PEN240(b)272.1PEN250(b)280.1PEN2301255.6270.3PEN2401259.3269.3PEN2501269.1PEN2303256.0270.0PEN2403261.9268.7PEN2503270.4PEN2305256.2269.7PEN2405263.6268.0PEN2505270.7F m true volume of fillerapparent volume occupied by the filler3 in which h is the viscosity of the suspension,h l is the viscosity of the suspending medium,f2is the volume frac-tion of theﬁller,f m is the maximum volume fraction that theﬁller can have,and K E is the Einstein coefﬁcient,whose value is known to be2.5for the dispersed sphericalﬁller.W.J.Yoon et al./Polymer41(2000)4933–49424939Fig.5.WAXD patterns of PEN isothermally crystallized at(A)230ЊC,(B)240ЊC and(C)250ЊC at various frequencies.Referring to the Mooney equation,the crystallization patterns of PEN melts at 230ЊC and at 250ЊC are distinc-tively different from each other.The Mooney equation predicts that the degree of increasing the suspension visc-osity with increasing f 2is greatly increased if the spheres form aggregates because the aggregation of spheres (spheru-litic crystallites or crystals in this study)increases the appar-ent ﬁller volume fraction.That is,the immobile portions (homogeneous molten PEN matrix in this study)caged by aggregated spheres also act as ﬁller portion.On this assump-tion,it may be suggested that an application of higher shear rate during isothermal crystallization tends to increase the heterogeneous crystallization characteristics.Hence,the higher nucleation density and higher growth rate of the nucleated crystallites is obtained at higher frequency,and the resultant is more abundant with less stable a -form crys-tals (this will be discussed later in detail).The melt endotherms of quiescently and shear-induced crystallized PEN were shown in Fig.4and the correspond-ing peak temperatures are listed in Table 1.The double melting endotherm behavior is displayed during heating the PEN sample in the DSC cell.In the melting process of the shear-induced crystallized PEN sample,three endother-mic peaks are identiﬁed;a broad endotherm,a low endotherm (T m H ),and a high endotherm (T m HH )as shown in Fig.4.The broad endotherm might be due to the thermal history during cooling and reheating,and both low and high endotherms are due to the melting of original lamella and recrystallized one,respectively.These results well coincide with the results of Zachman et al.[20]:(1)no change of crystal modiﬁcation is observed during DSC scanning;(2)the double melting behavior of PEN is due to the mechan-ism based on melting and recrystallization;(3)the b -form crystal has the T m higher than the a -form crystal by 2ЊC;and (4)the peaks of two forms of crystal are not separated in DSC thermogramsIn Fig.4(A)–(C)v 0rad =s indicates quiescent crystal-lization.(A)indicates that the PEN sample was crystallized at 230,240,and 250ЊC for the same time that required in the ARES experiments,and (B)expresses the PEN sample crys-tallized in an oil bath at the same temperature as in (A)for the time long enough to fully crystallize.Since the crystal-lization time in (A)is much shorter than in (B),an exother-mic peak is observed in the thermogram (A)at around 205ЊC.The v 0rad =s (b)curves in Fig.4(B)show a single melting peak.The T m shifts to higher temperature and peak width gets narrower as the crystallization time and tempera-ture are increased.This is attributable to the increased perfectness of the resultant crystal structure,which is observed more clearly when the sample is crystallized at higher temperature as can be seen in Fig.4(C).Only the b -form crystal exists when the sample is isothermally crys-tallized at 250ЊC after having melted at 300ЊC.This result matches well with the X-ray data.As mentioned the T m of the b -form crystal is higher than the a -form crystal by 2–4ЊC.It has been known that PEN has two different triclinic crystal structures.Buchner et al.reported that crystalW.J.Yoon et al./Polymer 41(2000)4933–49424940Fig.5.(continued )structures are inﬂuenced by both melting and isothermal crystallization temperature.They observed that the b -form crystal appeared mainly when PEN was isothermally crys-tallized above 230ЊC quiescently and the a -form crystal did below 230ЊC after having melted at 300ЊC [20].Fig.5presents WAXD patterns of PEN specimens shear-inducedcrystallized at (A)230ЊC,(B)240ЊC,(C)250ЊC at several frequencies.In Fig.5(A)the WAXD patterns for v 0rad =s shows diffraction peaks at 15.6and 23.3Њwhich correspond to (010)and (100)plane of the a -form crystal,respectively.The intensity of these peaks has a tendency to increase with increasing frequency.It means that the appli-cation of shear promotes the formation of the a -form crystal and the increase of frequency increases the content of the a -form crystal.In Fig.5(B)the (010)plane peak of the a -form crystal is smaller than that of the sample crystallized at 230ЊC in Fig.5(A)for v 0rad =s :However,the plane peak is increased with increasing frequency.In the case of the (100)plane peak,a shoulder appears at v 0rad =s :As frequency increases,the intensity of the plane peak standing for the a -form crystal shows tendency to increase.Particu-larly,for v 0rad =s in Fig.5(C)any plane peak of the a -form crystal is not observed,which is consistent with the results reported by Buchner et al.[20].The (010)and (100)plane peaks appear simultaneously,and keep on growing with increasing frequency.In addition,all diffraction peaks of Fig.5shift to lower angle when frequency is increased.This suggests that there is deformation in the crystal struc-tures as well.Thus,this X-ray trace of the sample is similar to those of Fig.5(A)and (B),suggesting similarity in the crystallization behavior at 230–250ЊC.In general,the b -form crystal is thermodynamically more stable but more difﬁcult to nucleate than the a -form crystal and the form of the crystal is largely determined by kinetic factors during crystallization such as the rate of nucleation and spherulite growth [21].In the case of the a -form crystal,one chain passes through the unit cell and the chains in the crystal are extended.In the case of the b -form crystal,however,four chains pass through the unit cell and the chains in the crystal are not completely extended.When the polymer is sheared,the number of crystallites increases with shear rate,representing faster nucleation.Wolkowicz [14]mentioned that the number of crystallites increased exponentially with time at all shear rates.Also,this can be conﬁrmed in Fig.6,which indicates that nuclea-tion becomes increasingly profuse with increasing frequency until the crystalline structure formed is no longer distinguishable with a microscope [3,22].Hence,the content of the a -form crystal in the speci-men increases with frequency because the a -form crys-tal is apt to nucleate due to fast nucleation.Consequently,the resultant a -form crystal is thermody-namically less stable than the b -form crystal because of much reduced entropy by molecular orientation under high shear force.References[1]Hill MJ,Keller A.J Macromol Sci (Phys)1969;B3(1):153.[2]Andrews EH.J Polym Sci 1966;A-2(4):663.[3]Haas TW,Maxwell B.Polym Eng Sci 1969;9:226.W.J.Yoon et al./Polymer 41(2000)4933–49424941(B)(A)(C)Fig.6.Polarizing optical micrographs of PEN crystallized at 240ЊC (A)v 0;(B)v 1;and (C)v 5:[4]Pennings AJ,van der Mark JMAA,Booj HC.kolloid Z v Z Polym1970;236:99.[5]Mackley MR,Keller A.Polymer1973;14:16.[6]Peterlin A.Polym Eng Sci1976;16:126.[7]Kobayashi K,Nagasawa T.J Macromol Sci(Phys)1970;B4:331.[8]Lagasse RR,Maxwell B.Polym Eng Sci1976;16:189.[9]Titomanlio G,Brucato V.Plastics Processing Society,The TenthAnnual Meeting,Akron,OH,1965,p.93.[10]Ulrich RD,Price FP.J Appl Polym Sci1976;14:401.[11]Eder G,Janeschizt-Kriehl H,Liedauer S.Progr Polym Sci1989;15:629.[12]Liedauer S,et al.Int Polym Proc VIII1993;3:236–44.[13]Moitzi J,Skallcky P.Polymer1993;34:3168.[14]Wolkowicz MD.J Polym Sci:Polym Symp1978;63:365.[15]Sherwood CH,Price FP,Stein RS.J Polym Sci;Polym Symp1977;63:77.[16]Imai M,et al.Phys.Rev.1995;B52:12696.[17]Kim JG,Park HJ,Lee JW.Korean J Rheol1997;4:174.[18]Carreau PJ,De Kee DCR,Chhabra RP.Rheology of polymericsystems,New York:Hanser,1997.[19]Nielsen LE.Polymer rheology,New York:Marcel Dekker,1977.[20]Buchner S,Wiswe D,Zachman HG.Polymer1989;30:480.[21]Zachman HG,Wiswe D,Riekel C.Macromol Chem Suppl1985;12:175.[22]Kim SP,Kim SC.Polym Eng Sci1993;33:83.W.J.Yoon et al./Polymer41(2000)4933–4942 4942。

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Computational noteElectronic dipole polarizabilities of polychlorinated dibenzofurans and semiempirical PM6level performanceAndrea Alparone,Vito Librando *Research Centre for Analysis,Monitoring and Minimization Methods of Environmental Risk,Department of Chemistry,University of Catania,viale A.Doria 8,Catania I-95125,ItalyPolychlorinated dibenzofurans (PCDFs)are widespread and per-sistent environmental contaminants [1].Electronic dipole polariz-abilities (a )of PCDFs were previously computed at the B3LYP level with cc-pVDZ,6-31G Ãand 6-31G ÃÃbasis sets in order to elucidate the effect of the substituent position on the congener speciﬁc tox-icity [2,3]and aqueous solubility [4].Recently,semiempirical PM6method [5]has been implemented in MOPAC 2007package [6],giving satisfactory estimates of molecular properties such as heats of formation [5]and electronic a values [7,8].This work is principally concerned on the validation of the PM6method in the determination of a values,focusing attention on DF and the 135PCDF congeners (Fig.S1of the Supporting Material).Static a ij (i,j =x ,y ,z )components were calculated at the AM1,PM3and PM6levels.Additionally,we computed a ij values for DF and its octacloro substituted congener at the HF,MP2and PBE0levels with aug-cc-pVDZ basis set on the B3LYP/6-31G ÃÃgeometry.Present computations were performed with MOPAC 2007[6]and PC GAMESS [9,10]programs.Calculated average polarizability,h a i ¼1=3ða xx þa yy þa zz Þ,and polarizability anisotropy,D a ¼f 1½ða xx Àa yy Þ2þða xx Àa zz Þ2þða yy Àa zz Þ2þ6ða 2xy þa 2xz þa 2yz Þ g 1=2,are given in Tables S1–S3of the Supporting Material.The results show that PM6is noticeably superior to both the commonly em-ployed semiempirical AM1and PM3methods,reproducing the PBE0/aug-cc-pVDZ (and also MP2/aug-cc-pVDZ)h a i values of DF and 1,2,3,4,5,6,7,8-OCDF within 5a.u.(2–3%)and D a data within 8–11a.u.(3–8%),geometrical effects (PM6vs.B3LYP/6-31G ÃÃ)being almost negligible.Note that the corresponding deviations for h a i obtained using the AM1,PM3and B3LYP/6-31G ÃÃ[3]data are substantially larger,being 36–94a.u.(25–34%),41–76a.u.(27–28%),24–47a.u.(16–17%),respectively,while those for D a are 22–25a.u.(9–20%),16–43a.u.(12–18%)and 11–14a.u.(4–11%),respectively.However,least-mean squared ﬁtting linear relationships between the semiempirical and B3LYP/6-31G ÃÃh a i and D a data (See Figs.S2and S3of the Supporting Material)aresatisfactory (r 2=0.97–1.00).As can be appreciated from Figs.S4and S5of the Supporting Material,on passing from PM6to AM1(PM3),h a i and D a values decrease and increase by 21–33%(26–28%)and 13–31%(19–23%),respectively.These discrepancies are principally originated from differences in the out of the plane polarizability component.Due to its relatively low computational cost and good accuracy,PM6is a promising method for the predic-tion of a of large p -conjugated systems and is particularly indi-cated for QSPR studies.AcknowledgementWork partially supported by MIUR,Rome.Appendix A.Supplementary dataSupplementary data associated with this article can be found,in the online version,at doi:10.1016/j.theochem.2008.09.023.References[1]S.Safe,Crit.Rev.Toxicol.21(1990)51.[2]S.Hirokawa,T.Imasaka,T.Imasaka,Chem.Res.Toxicol.18(2005)232.[3]C.Gu,X.Jiang,X.Ju,G.Yu,Y.Bian,Chemosphere 67(2007)1325.[4]G.Yang,X.Zhang,Z.Wang,H.Liu,X.Ju,J.Mol.Struct.(Theochem)766(2006)25.[5]J.J.P.Stewart,J.Mol.Model.13(2007)1173.[6]J.J.P.Stewart,MOPAC 2007,Stewart Computational Chemistry,Colorado Springs,CO,USA,[7]T.Puzyn,N.Suzuki,M.Haranczyk,J.Rak,J.Chem.Inf.Model.48(2008)1174.[8]A.Alparone,V.Librando,Z.Minniti,Chem.Phys.Lett.460(2008)151.[9]M.W.Schmidt,K.K.Baldridge,J.A.Boatz,S.T.Elbert,M.S.Gordon,J.H.Jensen,S.Koseki,N.Matsunaga,K.A.Nguyen,S.J.Su,T.L.Windus,M.Dupuis,J.A.Montgomery,put.Chem.14(1993)1347.[10]A.A.Granovsky,PC GAMESS version 7.0,Available from:<http://classic.chem.msu.su/gran/gamess/index.html/>.0166-1280/$-see front matter Ó2008Elsevier B.V.All rights reserved.doi:10.1016/j.theochem.2008.09.023*Corresponding author.Tel.:+39957385201;fax:+3995580138.E-mail address:vlibrando@unict.it (V.Librando).Journal of Molecular Structure:THEOCHEM 894(2009)128Contents lists available at ScienceDirectJournal of Molecular Structure:THEOCHEMj o ur na l h o me pa ge :w w w.e ls e v ie r.c o m/lo c a t e/t he o c hem。

英国article格式

英国article格式一篇Article格式显而易见, 分为四个部分Title, Introductio n, Main Body, Conclusion. 许多小伙伴们面对Article格式一头雾水, 自己仔细研究却发现越看越迷糊, 不仅是格式问题, 从读懂题目到整理大量的资料和数据, 没有哪一步是轻而易举的, 而且Article成绩直接影响您是否能够顺利毕业.Essay和article是国外大学中两种常见的写作形式。

但是作为在外留学的小伙伴们，你是否知道什么essay，什么article？essay 和article区别解析。

维基百科中提到，"An essay is,generally,a pi ece of writing that gives theauthor's own argument"。

在一篇essay中作者，会给出自己的argument。

意为读者可以通过多个有效论据，推导出某个正确的结论；或者根据有力的论据，归纳出某个可能性的结论。

正式的essay特点是目的严肃，严密组织的逻辑，内容较长。

非正式的essay具有强烈的个人色彩，如自我表露、个人品味和经历等，结构散漫，话题新奇。

一篇essay是作者自我表达的载体。

essay写作有很多的细分类，如故事类、描述类、议论类等。

ess ay的目的和内容通常由essay的类型来决定。

如果你正在写故事类e ssay，那么要注重讲故事的方式，以便能吸引读者。

如果是描述类es say，那么要注重场景的描写，以便给读者留下深刻印象。

如果是议论类essay，那么要关注有力的论据、严密的逻辑，来支撑你的观点，以便说服读者。

有趣的是，在英语中essay最原始的意思指"an attempt"。

而article的目的是展示事实、信息、新闻，是一种直接的知识，具有who，what，when,，where，why，how等六要素。

article的用法及短语

article的用法及短语
article：
n.文章;(报刊上的)论文;报道;(协议、契约的)条款;物件(尤指整套中的一件)；
vi.使受协议条款的约束;以协议（或契约）约束；
短语搭配：
Featured Article特色条目；
Article Center帮助中心；
Article Title文章标题；
Next Article下一篇
扩展资料
But, this article is not about me.
但是，这篇文章不是关于我的.。

As I sit down to write this article, I have but one intention.
我之所以坐下来写这篇文章，是因为我只有一个意图。

Which of these places would you like to visit most?Write an article about why you would like to go there.
你最想到这些地方中的哪个地方参观？写一篇有关你想去那个地方的原因的文章。

用article造句带翻译

用article造句带翻译Title: The Importance of Time Management in Achieving Success。

时间管理在取得成功中的重要性。

Time is a precious commodity that cannot be bought, sold, or traded. It is a finite resource that is shared equally by everyone. However, how we use our time can make all the difference in achieving success. Time management is crucial in maximizing productivity, achieving goals, and maintaining a healthy work-life balance.时间是一种珍贵的资源，不能买卖或交换。

它是每个人平等分享的有限资源。

然而，我们如何利用时间可以在取得成功方面产生重大影响。

时间管理对于最大化生产力、实现目标和保持健康的工作与生活平衡至关重要。

Effective time management involves setting priorities, creating a schedule, and sticking to it. It requiresdiscipline, focus, and commitment. The first step is to identify what is important and what can be delegated or eliminated. This requires a clear understanding of goals and objectives. Once priorities are established, a schedule can be created that allocates time for each task, project, or activity. This schedule should be realistic and flexible enough to accommodate unexpected events or changes.有效的时间管理包括设置优先级、创建时间表并坚持执行。

广东省深圳市深圳高级中学高一下学期期中考试英语试题(原卷版)

D.To cure a young owl.
6.What made the chick calm down?
A.A new nest.
B.Some food.
C.A recording.
D.Its parents.
7.How would the author feel about the oute of the event?
A nervous night to be sure, but sometimes the spirits of nature smile on us all! The homeowner called to say that the parents had responded to the recordings. I drove over and saw the chick in the nest looking healthy and active. And it was acpanied in the nest by the greatest sight of all — LUNCH! The parents had done their duty and would probably continue to do so.
Speaking Broadly
This podcast is made for advanced learners. Explained through discussion and interviews, each episode has nonnative English speakers and every recording also has expert feedback. You will see some mon mistakes made by English learners and you can improve your English by learning from those mistakes.

羰基保护_sdarticle

Copper(II)tetraﬂuoroborate as a novel and highly eﬃcientcatalyst for acetal formationRaj Kumar and Asit K.Chakraborti *Department of Medicinal Chemistry,National Institute of Pharmaceutical Education and Research (NIPER),S ector 67,S .A.S .Nagar,Punjab 160062,IndiaReceived 24July 2005;revised 23September 2005;accepted 28September 2005Available online 11October 2005Dedicated to Professor Mark S.CushmanAbstract—Commercially available copper(II)tetraﬂuoroborate hydrate has been found to be a highly eﬃcient catalyst for dimethyl/diethyl acetal formation in high yields from aldehydes and ketones by reaction with trimethyl/triethyl orthoformate at room tem-perature and in short period.Acetalisation was carried out under solvent-free conditions with electrophilic aldehydes/ketones.For weakly electrophilic aldehydes/ketones (e.g.,benzaldehyde,cinnamaldehyde and acetophenone)and for aldehydes having a substi-tuent that can coordinate with the catalyst,the corresponding alcohol was used as solvent.Ó2005Elsevier Ltd.All rights reserved.1.IntroductionProtection of aldehyde and ketone carbonyl groups is a frequently desired exercise in organic synthesis as it is often necessary to carry out a reaction on a multifunc-tional substrate without aﬀecting an aldehyde/ketone group.One convenient method of protecting aldehydes and ketones is to convert them into the corresponding acetals.1Acetalisation can be achieved by treatment with alcohols in the presence of a protic 1,2or Lewis 1,3acid catalyst.A common regimen for acetal formation is protic 1,4or Lewis 1,5acid catalysed reaction of alde-hydes and ketones with trialkyl orthoformates.Other methods use MeOH–PhSO 2NHOH–MeONa,1b alkoxy-silanes in the presence of TMSOTf,1b (EtO)3CH–DDQ–EtOH 6and CAN–Na 2CO 3–ROH.7However,these methods have one or more drawbacks such as long reaction times,high temperatures,use of costly re-agents/catalysts,use of additional reagents,requirement of special eﬀorts for catalyst preparation,requirement of stoichiometric amount of the catalysts,the need to use special apparatus and moderate yields and side reac-tions.Thus,the development of an improved method is still desirable.2.Results and discussionsWhen designing a new method,we realised that the use of trialkyl orthoformates as the acetalisation agent in the presence of a suitable transition metal catalyst should constitute a better procedure operable under mild conditions.The eﬃciency of the method would depend upon the coordination property of the metal catalyst to activate trialkyl orthoformate and/or the carbonyl substrate.Recently,we have reported that copper(II)tetraﬂuoroborate is an excellent catalyst for electrophilic activation during acylation,8diacetate for-mation 9and thia-Michael addition 10reactions.In this report,we disclose a highly eﬃcient acetal formation reaction catalysed by copper(II)tetraﬂuoroborate (Scheme 1).Various aldehydes and ketones were treated with tri-methyl orthoformate in the presence of Cu(BF 4)2Æx H 2O0040-4039/$-see front matter Ó2005Elsevier Ltd.All rights reserved.doi:10.1016/j.tetlet.2005.09.168Keywords :Dimethyl acetals;Diethyl acetals;Aldehydes;Ketones;Copper(II)tetraﬂuoroborate hydrate;Catalyst;Trimethyl orthofor-mate;Triethyl orthoformate.*Corresponding author.Tel.:+9101722214682686;fax:+9101722214692;e-mail:akchakraborti@niper.ac.in(1mol %)at $25–30°C under neat conditions.The reactions were monitored by IR and GCMS and the optimum results are provided in Table 1.Substituted benzaldehydes with Me,Cl,Br,NO 2and OCOPh groups (entries 1–7),1-naphthaldehyde (entry 8),9-anthraldehyde (entry 9),aryl alkyl aldehydes (entries 10and 11)and saturated cyclic ketones (entries 12and 13)aﬀorded excellent results after 2–15min.The reac-tions could also be monitored visually:immediately after the addition of the catalyst to the mixture of alde-hyde and trimethyl orthoformate an exothermic reaction takes place and the reaction mixture becomes homoge-neous (for solid aldehydes)indicating completion of ace-tal formation.In the case of 9-anthraldehyde,as the product was solid,a small excess (3equiv)of trimethyl orthoformate was required.In the cases of benzaldehyde,cinnamaldehyde,aceto-phenone and aldehydes bearing substituents that are capable of coordinating with the metal ion,the acetalformation was slow under neat conditions.However,in these cases,the reactions proceeded well using MeOH as solvent aﬀording excellent yields (Table 2).The phenyl/styryl groups in benzaldehyde,cinnamalde-hyde and acetophenone made aldehyde/ketone carbonyl less electrophilic due to resonance and inhibited the eﬀective formation of coordinate bonds with the cata-lyst.For aldehydes bearing substituents that can coordi-nate with the metal cation (e.g.,OR,F,CN,NMe 2,etc.)no eﬀective activation of trimethyl orthoformate by the metal salt took place and acetal formation was retarded.The moderate yield obtained with 4-dimethylamino-benzaldehyde after 12h (Table 2,entry 6)supported the role of a coordinating eﬀect of the substituent in inﬂuencing acetal parison of acetal for-mation from 4-methylbenzaldehyde,4-chlorobenzalde-hyde and 4-nitrobenzaldehyde (Table 1,entries 1–3)with those from 4-methoxybenzaldehyde,4-ﬂuorobenz-aldehyde and 4-cyanobenzaldehyde (Table 2,entries 2–4),respectively,highlighted the coordinating eﬀect of the substituents in the latter cases.The role of MeOH may be explained by the fact that initial reaction ofTable 2.Cu(BF 4)2Æx H 2O catalysed dimethyl acetal formation from aldehydes/ketones in dry MeOH aEntryAldehyde/ketone Time (min)Yield (%)b ,cCHO1R =H 593d 2R =F 10953R =CN 10924R =OMe 20915R =NMe 212h58CHOO R6R =Me 30887R =c -C 5H 910928CHOPh20919O308510S 2082O111.5h 96aThe aldehyde/ketone (2.5mmol)in dry methanol (1mL)was treated with CH(OMe)3(2.0equiv)in the presence of Cu(BF 4)2Æx H 2O (1mol %)at room temperature ($25–30°C).bIsolated yield of the corresponding acetal.cThe products were characterised by IR and NMR.dA 36%yield was obtained on carrying out the reaction under neat conditions.Table 1.Cu(BF 4)2Æx H 2O catalysed dimethyl acetal formation from aldehydes/ketones under solvent-free conditions aEntryAldehyde/ketone Time (min)Yield (%)b ,cCHO3R 1R 21R 1=R 2=H;R 3=Me 5922R 1=R 2=H;R 3=Cl 5903R 1=R 2=H;R 3=NO 23924R 1=R 2=H;R 3=OCOPh 5915R 1=Br;R 2=R 3=H 5886R 1=Cl;R 2=R 3=H 5907R 1=R 3=H;R 2=NO 28928CHO15859CHO1582d10Ph CHO 28511CHOPh38612O57813O295aThe aldehyde/ketone (2.5mmol)was treated with CH(OMe)3(2.0equiv)in the presence of Cu(BF 4)2Æx H 2O (1mol %)at room temperature ($25–30°C)under neat conditions.bIsolated yield of the corresponding acetal.cThe products were characterised by IR,NMR.dThe reaction was carried out using 3equiv of CH (OMe)3.8320R.Kumar,A.K.Chakraborti /Tetrahedron Letters 46(2005)8319–8323aldehyde with MeOH leads to the formation of a hemi-acetal,which undergoes nucleophilic attack on trimethyl orthoformate complexed with Cu(BF 4)2Æx H 2O and results in acetal formation.4Since there are limited reports for diethyl acetal forma-tion,3e,f,4,5c–e,gwe planned to evaluate the catalytic eﬃ-ciency of Cu(BF 4)2Æx H 2O during the reaction of a few representative aldehydes and ketones with triethyl orthoformate (Table 3).Excellent results were obtained in each case.As observed in the case of dimethyl acetal formation,the reactions of benzaldehyde,cinnamaldehyde and aceto-phenone required dry EtOH as solvent for diethyl acetal formation.A comparison of the results of entries 1and 6(Table 2)prompted us to study selective acetal formation during intermolecular competition between benzaldehyde 1and 4-dimethylaminobenzaldehyde 2.Thus,a mixture of 1(2.5mmol)and 2(2.5mmol)in dry MeOH (1mL)was treated with trimethyl orthoformate (5mmol)in the presence of Cu(BF 4)2Æx H 2O (1mol %)for 5min at room temperature (Scheme 2).Excellent selectivity was observed,(dimethoxymethyl)benzene 3and 4-(dimethoxymethyl)-N ,N -dimethylaniline 4were formed in a ratio of 88:12(NMR).Similarly,the diﬀer-ence in the rate of reaction of 1and acetophenone 5(Table 2,compare the results of entries 1and 11)encouraged us to study the selectivity of acetal forma-tion during inter-and intramolecular competition stud-ies involving aldehyde and ketone carbonyl groups.Thereaction of 1(2.5mmol)and 5(2.5mmol)with trimethyl orthoformate (5mmol)in dry MeOH (1mL)in the pres-ence of Cu(BF 4)2Æx H 2O (1mol %)at room temperature for 5min (Scheme 2)resulted in the formation of 3and 2,2-dimethoxy-1-phenylethane 6in a ratio of 86:14(NMR).The reaction of 4-acetylbenzaldehyde 7(2.5mmol)with trimethyl orthoformate (5mmol)in MeOH (1mL)in the presence of Cu(BF 4)2Æx H 2O (1mol %)for 5min at room temperature resulted in the formation of 4-(dimethoxymethyl)acetophenone 8and 2,2-dimethoxy-(40-dimethoxymethyl)-1-phenyl-ethane 9in a ratio of 77:23(GCMS).3.ConclusionsWe have described herein the use of Cu(BF 4)2Æx H 2O as ahighly eﬃcient and reusable catalyst for dimethyl and diethyl acetal formation at room temperature.The advantages include,(i)the use of a cheap,easy to handle and commercially available catalyst,(ii)room tempera-ture reaction conditions,(iii)short reaction times,(iv)high yields and (v)excellent chemoselectivity.4.Experimental4.1.Typical procedure for acetal formation under neat conditionsTo a magnetically stirred mixture of 4-methylbenzalde-hyde (0.3g, 2.5mmol)and trimethyl orthoformate (0.53g,5mmol),Cu(BF 4)2Æx H 2O (6.0mg,0.025mmol,1mol %)was added and the mixture was stirred at 25–30°C until completion of the reaction (5min,TLC,IR).The mixture was diluted with saturated aq NaHCO 3(10mL)and extracted with EtOAc (3·10mL).TheTable 3.Cu(BF 4)2Æx H 2O catalysed diethyl acetal formation from aldehydes and ketones aEntryAldehyde/ketone Time (min)Yield (%)b ,cCHO1R =H 1093d 2R =Me 3953R =NO 25954CHO Ph 10925CHOPh 380d6O375The aldehyde/ketone (1equiv)was treated with CH(OEt)3(2.0equiv)in the presence of Cu(BF 4)2Æx H 2O (1mol %)at rt ($25–30°C)in the absence of solvent (except for entries 1,5and 7).bIsolated yield of the corresponding acetal.cThe products were characterised by IR,NMR.dThe reaction was carried out in dry ethanol (1mL).R.Kumar,A.K.Chakraborti /Tetrahedron Letters 46(2005)8319–83238321combined EtOAc extracts were washed with water(2·10mL),dried(Na2SO4)and concentrated under reduced pressure to aﬀord4-(dimethoxy)methylbenzene(colour-less oil,0.415g,92%,entry1,Table1),IR(neat):2936, 2828,1618,1447,1353,1201,1105,1054,912, 807cmÀ1;1H NMR(300MHz,CDCl3):d=2.33(s, 3H),3.30(s,6H),5.35(s,1H),7.15(d,2H,J=7.6Hz), 7.32(d,2H,J=7.6Hz);13C NMR(75MHz,CDCl3): d=21.2,52.53,103.16,126.56,128.81,135.13,138.06, identical with an authentic sample.5e5.Representative experimental procedure for acetalformation in the presence of solventTo a magnetically stirred mixture of4-cyanobenzalde-hyde(0.327g, 2.5mmol)and trimethyl orthoformate (0.53g,5mmol)in dry MeOH(1mL),Cu(BF4)2Æx H2O (6.0mg,0.025mmol,1mol%)was added and the mix-ture was stirred at25–30°C until completion of the reac-tion(10min,TLC,IR).The reaction mixture was diluted with saturated aq NaHCO3(10mL)and extracted with EtOAc(3·10mL).The combined EtOAc extracts were washed with water(2·10mL), dried(Na2SO4)and concentrated under reduced pres-sure to aﬀord pure4-(cyano)dimethoxymethylbenzene (colourless oil,0.407g,92%,entry3,Table2),IR(neat): 2938,2832,2229,1353,1209,1101,1057,988,822, 556cmÀ1;1H NMR(300MHz,CDCl3):d=3.32(s, 6H),5.43(s,1H),7.50(d,2H,J=8.3H z),7.68(d, 2H,J=8.3H z);13C NMR(75MHz,CDCl3): d=52.56,101.62,112.14,118.52,127.45,131.91, 143.10,identical with an authentic sample.2cThe remaining reactions were carried out following these general procedures.On each occasion,the spectral data(IR,1H NMR and13C NMR)of the prepared known compounds were found to be identical with those reported in the literature.The following compounds had not been reported.2-(Bromo)dimethoxymethylbenzene(Table1,entry5): IR(neat):2933,2829,1468,1364,1204,1103,1057, 980,755cmÀ1.1H NMR(300MHz,CDCl3):d=3.35 (s,6H),5.55(s,1H),7.14(t,1H,J=7.5Hz),7.28(t, 1H,J=7.5Hz),7.52(d,1H,J=7.6Hz),7.59(d,1H, J=7.6Hz).13C NMR(75MHz,CDCl3):d=53.57, 102.71,122.75,126.92,128.18,129.84,132.66,136.68. Anal.Calcd for C9H11BrO2:C,46.78;H,4.80.Found. C,46.80;H, 4.82.2-(Chloro)dimethoxymethylbenzene (Table1,entry6):IR(neat):2934,2830,1366,1201, 1107,1058,981,756cmÀ1.1H NMR(300MHz, CDCl3):d=3.37(s,6H),5.62(s,1H),7.22–7.29(m, 2H),7.33–7.36(m,1H),7.60–7.63(m,1H).13C NMR (75MHz,CDCl3):d=53.68,100.86,126.45,128.02, 129.50,129.65,133.11,135.28.Anal.Calcd for C9H11ClO2:C,57.92;H, 5.94.Found.C,57.91;H, 5.97.9-Dimethoxymethylanthracene(Table1,entry9): Mp:107–108°C IR(KBr):2932,1448,1186,1105, 1066,891,740cmÀ1.1H NMR(300MHz,CDCl3): d=3.50(s,6H),6.53(s,1H),7.38–7.61(m,4H),7.93 (d,2H,J=8.4Hz),8.39(s,1H),8.68(d,2H, J=8.4Hz).13C NMR(75MHz,CDCl3):d=53.68,100.86,126.45,128.02,129.50,129.65,133.11,135.28. Anal.Calcd for C17H16O2:C,80.93;H,6.39.Found. C,80.96;H,6.41.3,4-(Dimethoxy)dimethoxymethylbenz-ene(Table2,entry6):IR(neat):2937,2832,1607, 1594,1414,1259,1194,1136,1102,990,863,863,795, 762cmÀ1.1H NMR(300MHz,CDCl3):d=3.32(s, 6H),3.88(s,3H),3.90(s,3H),5.33(s,1H),6.84–6.97 (m,1H), 6.98–6.99(m,2H).13C NMR(75MHz, CDCl3):d=52.34,55.53,102.86,109.33,110.40, 119.00,126.48,130.61,148.64.Anal.Calcd for C11H16O4C,62.25;H,7.60.Found.C,62.23;H,7.63. 4-Cyclopentyloxy-3-methoxy dimethoxymethylbenzene (Table2,entry7):IR(neat):2954,2829,1607,1510, 1351,1264,1160,1102,1053,988,862,804cmÀ1.1H NMR(300MHz,CDCl3):d=1.57–1.61(m,2H), 1.79–1.97(m,6H),3.32(s,6H),3.85(s,3H),4.73–4.79 (m,1H),5.31(s,1H),6.84(d,1H,J=8.1Hz),6.93–6.97(m,2H).13C NMR(75MHz,CDCl3):d=24.03, 32.77,52.75,55.95,80.32,103.29,110.10,114.16, 119.07,130.54,147.73,149.81.Anal.Calcd for C15H22O4:C,67.64;H,8.33.Found.C,67.63;H,8.35.Supplementary dataSupplementary data associated with this article can be found,in the online version,at doi:10.1016/j.tetlet. 2005.09.168.References and notes1.(a)Meskens,F.A.J.Synthesis1981,501–521;(b)Greene,T.W.;Wuts,P.G.M.In Protecting Groups in Organic Synthesis,3rd ed.;John Wiley and Sons:New York,1999.2.p TsOH-MgSO4:(a)Lu,T.-J.;Yang,J.-F.;Sheu,L.-J.J.Org.Chem.1995,60,2931–2934;p TsOH under microwave heating:(b)Pe´rio, B.;Dozias,M.-J.;Jacquault,P.;Hamelin,J.Tetrahedron Lett.1997,38,7867–7870;Polymer-supported acid catalysts in an electroosmotic ﬂow reactor:(c)Wiles, C.;Watts,P.;Haswell,S.J.Tetrahedron2005,61,5209–5217.3.Montmorillonite K-10:(a)Li,T.-S.;Li,S.-H.;Li,J.-T.;Li,H.-Z.J.Chem.Res.(S)1997,26–27;I2under microwaveheating:(b)Kalita, D.J.;Borah,R.;Sarma,J. C.Tetrahedron Lett.1998,39,4573–4574;MCM-41:(c) Tanaka,Y.;Sawamura,N.;Iwamoto,M.Tetrahedron Lett.1998,39,9457–9460;I2:(d)Basu,M.K.;Samajdar, S.;Becker,F.F.;Banik,B.K.Synlett2002,319–321;CoCl2:(e)Velusamy,S.;Punniyamurthy,T.Tetrahedron Lett.2004,45,4917–4920;RuCl3:(f)De,S.K.;Gibbs, R.A.Tetrahedron Lett.2004,45,8141–8144.4.TBATB:Gopinath,R.;Haque,S.J.;Patel,.Chem.2002,67,5842–5845.5.Rh(II)triphos:(a)Ott,J.;Tombo,G.M.R.;Schmid,B.;Venanzi,L.M.;Wang,G.;Ward,T.R.Tetrahedron Lett.1989,30,6151–6154;TiCl4:(b)Clerici,A.;Pastori,N.;Porta,O.Tetrahedron1998,54,15679–15690;ZrCl4:(c) Firouzabadi,H.;Iranpoor,N.;Karimi,B.Synlett1999, 321–323;NBS:(d)Karimi,B.;Seradj,H.;Ebrahimian,G.-R.Synlett1999,1456–1458;Bi(OTf)3:(e)Leonard,N.M.;Oswald,M.C.;Freiberg,D.A.;Nattier,B.A.;Smith,R.C.;Mohan,.Chem.2002,67,5202–5207;B10H14:(f)Lee,S.H.;Lee,J.H.;Yoon,C.M.Tetrahedron Lett.2002,43,2699–2703;LiBF4:(g)Hamada,N.;Kazahaya,K.;Shimizu,H.;Sato,T.Synlett2004,1074–8322R.Kumar,A.K.Chakraborti/Tetrahedron Letters46(2005)8319–83231076;InCl3:(h)Ranu,B.C.;Jana,R.;Samanta,S.Adv.S ynth.Catal.2004,346,446–450.6.Karimi, B.;Ashtiani, A.M.Chem.Lett.1999,1199–1200.7.Nair,V.;Rajan,R.;Balagopal,L.;Nair,L.G.;Ros,S.;Mohanan,K.Indian J.Chem.2005,44B,141–143.8.Chakraborti,A.K.;Gulhane,R.;Shivani Synthesis2004,111–115.9.Chakraborti,A.K.;Thilagavathi,R.;Kumar,R.Synthe-sis2004,831–833.10.Garg,S.K.;Kumar,R.;Chakraborti,A.K.TetrahedronLett.2005,46,1721–1724.R.Kumar,A.K.Chakraborti/Tetrahedron Letters46(2005)8319–83238323。

article造句

article造句article造句1、This article mainly studies the interference coupling of external electromagnetic field to STP.本文主要研究外部电磁场对屏蔽双绞线的干扰耦合情况。

2、Henry clipped the article out of the newspaper.亨利从报上剪下了那篇文章。

3、The article suggests that the character will be limited to a cameo part in the film.文章建议说，品格将被限制在演一个部分，在这部影片中。

4、That article on the refugee problem sure was a think piece!那篇关于难民问题的文章的确是篇引人深思的作品啊。

5、The article was highly defamatory.这篇文章充满诽谤。

6、This article aims to explain what you need to do to facilitate a retrospective for your team.本文旨在说明为推动你的团队进行回顾，你需要做些什么。

7、The typist turned to and finished the article in two hours.打字员着手打起来，花了两个小时把这篇文章打好了。

8、It was nothing now, a small, cheap, purchased article of finery.当我一戴上手?，手?却显得死气沉沉，变成俗气便宜的小饰物。

9、She asked him to contribute a biweekly article on European affairs她约他每两周写一篇有关欧洲情况的文稿。

article的用法总结大全

article的用法总结大全（学习版）编制人：__________________审核人：__________________审批人：__________________编制学校：__________________编制时间：____年____月____日序言下载提示：该文档是本店铺精心编制而成的，希望大家下载后，能够帮助大家解决实际问题。

文档下载后可定制修改，请根据实际需要进行调整和使用，谢谢!并且，本店铺为大家提供各种类型的经典范文，如英语单词、英语语法、英语听力、英语知识点、语文知识点、文言文、数学公式、数学知识点、作文大全、其他资料等等，想了解不同范文格式和写法，敬请关注!Download tips: This document is carefully compiled by this editor.I hope that after you download it, it can help you solve practical problems. The document can be customized and modified after downloading, please adjust and use it according to actual needs, thank you!In addition, this shop provides various types of classic sample essays, such as English words, English grammar, English listening, English knowledge points, Chinese knowledge points, classical Chinese, mathematical formulas, mathematics knowledge points, composition books, other materials, etc. Learn about the different formats and writing styles of sample essays, so stay tuned!article的用法总结大全article的意思article的简明意思n. 文章；物品；条款；[语]冠词vt. 订契约英式发音 ['ɑːtɪkl] 美式发音 ['ɑːrtɪkl]article的词态变化为:过去式: articled 过去分词: articled 现在分词: articling 第三人称单数: articlesarticle的详细意思在英语中，article不仅具有上述意思，还有更详尽的用法，article作名词 n. 时具有文章，论文，报道;物品，物件;【语法】冠词;条款，条文，项目，项;商品，制品;一件;【动】节;正式宣言的全文等意思，article作动词 v. 时具有订约将...收为学徒或见习生;把...逐条登载;分条解释;列举（罪状），将…逐条罗列;使受协议条款的约束，用条款约束;约定，订契约;对…提出控诉等意思，article的具体用法用作名词 n.article的基本意思是“物件”“物品”,常指一套中之一。

igcse英语article范文

igcse英语article范文The IGCSE English examination is a challenging yet rewarding experience for students seeking to demonstrate their proficiency in the English language. As an international qualification recognized globally, the IGCSE English exam assesses a range of essential skills, including reading comprehension, writing, and language use. Preparing for this examination requires a comprehensive understanding of the assessment criteria and a dedication to honing one's abilities in various aspects of the English language.One of the key components of the IGCSE English exam is the article writing task. This genre of writing is designed to test a student's ability to effectively communicate ideas, express opinions, and engage the reader. The article format allows students to showcase their creativity, organizational skills, and command of the English language.When approaching the article writing task, it is essential to understand the specific requirements and expectations outlined by the exam board. The IGCSE English syllabus typically specifies thelength, format, and content guidelines for the article. Students must be mindful of these parameters and ensure that their writing adheres to the prescribed structure.The opening paragraph of the article is crucial in capturing the reader's attention and setting the tone for the entire piece. It should introduce the central theme or focus of the article, providing a clear and concise overview of the main ideas to be explored. Effective use of hooks, such as thought-provoking questions or intriguing statements, can help draw the reader in and encourage them to continue reading.Following the introduction, the body paragraphs of the article should delve deeper into the chosen topic, presenting a logical and well-structured argument or discussion. Each paragraph should have a clear topic sentence that guides the reader through the progression of ideas. The use of supporting evidence, examples, and relevant facts can strengthen the overall persuasiveness and credibility of the article.Effective article writing also requires a strong command of language and a keen eye for detail. Students should strive to use a diverse vocabulary, employ various sentence structures, and maintain a cohesive and coherent flow throughout the piece. Attention to grammar, spelling, and punctuation is essential to ensure the articleis polished and professional in its presentation.One of the hallmarks of a well-written IGCSE English article is the ability to present a balanced and objective perspective on the chosen topic. While students are encouraged to express their own opinions and viewpoints, they should also acknowledge and address alternative perspectives or counterarguments. This demonstrates a nuanced understanding of the subject matter and a willingness to engage in critical thinking.In addition to the content and language proficiency, the IGCSE English article writing task also requires students to consider the intended audience and the appropriate tone and style for the piece. The article should be tailored to the specific needs and expectations of the reader, whether it be a general public audience or a more specialized readership.Effective article writing also involves the skillful use of organizational techniques, such as the incorporation of headings, subheadings, and transitional phrases. These elements help to guide the reader through the article, ensuring a clear and logical flow of ideas. Additionally, the use of relevant and engaging visuals, such as images or infographics, can enhance the overall presentation and appeal of the article.Throughout the writing process, students should engage in a cycle of drafting, revising, and editing to refine their work. This iterative approach allows for the identification and correction of any errors or weaknesses, as well as the opportunity to enhance the overall quality and coherence of the article.Ultimately, the IGCSE English article writing task is a valuable opportunity for students to showcase their language proficiency, critical thinking skills, and ability to communicate effectively in written form. By understanding the expectations of the exam and dedicating time to honing their writing abilities, students can approach this component of the IGCSE English examination with confidence and a strong foundation for success.。

article语法

不定冠词的用法
不定冠词有两个，a 和 an。a 用在辅音开头的单词前面， an用于以元音开头的单词前。如：a apple, an egg。
定冠词的用法
定冠词和名词连用，表示某个或某些特定的人或东西。例如，“the car”表示特定的汽车。
注意事项
冠词省略
在某些情况下，冠词可以被省略。例如，在简短对话或口语中，人们常常省略不必要的冠词。
article语法
目录
• 什么是article语法 • Article语法的种类和构成 • Article语法的作用和应用场景 • Article语法的特殊规则和注意事项 • Article语法的学习和提高方法
01 什么是article语法
定义
• Article语法是指一种用于描述名词或名词短语的语法规则，它规定了名词或名词短语在句子中的出现方式和使用方法。在英语、法语、德语等语言中，article语法被广泛使用，它包括不定冠词、定冠词、零冠词等不同的形式。
3 学习其他语言中类似的语法结构
• 学习其他语言中类似的语法结构有助于更好地理解Article语法。例如，学习拉丁语可以更好地理解古汉语中的复杂词序和变格；学习英语可以更好地理解时态和语态等语法概念。通过学习其他语言中的类似语法结构，可以加深对 Article语法的理解和运用能力。
THANKS
练习使用语法
学习语法不仅仅是记忆规则，更重要的是能够在实际语境中运用。可以通过写作、口语练习、阅读和翻译等方式来加强语法运用能力。在练习过程中，要不断纠正自己的错误，逐渐提高语法的准确性。
对比其他语言
了解不同语言之间的语法差异有助于更好地掌握Article语法。例如，英语和汉语之间的词序、时态、语态等方面存在较大差异，通过对比可以更好地理解Article语法的特点。

article短语搭配

article短语搭配以下是一些与"article" 相关的常见短语搭配：●Read an Article:"I read an interesting article about climate change in the newspaper."●Write an Article:"She is planning to write an article on sustainable living for the magazine."●Featured Article:"The website's homepage has a featured article on the latest technology trends."●Magazine Article:"The fashion magazine published an article on the latest trends in streetwear."●Newspaper Article:"The newspaper article provided an in-depth analysis of the current political situation."●Scientific Article:"Scientists often publish their research findings in scientific articles."●Online Article:"I came across an interesting online article about healthy eating habits."●Opinion Article:"The editorial section of the magazine includes opinion articles from various contributors."●Guest Article:"The blog features a guest article by a renowned expert in the field."●Feature Article:"The Sunday magazine includes a feature article on a local artist."●Article Summary:"Before reading the whole article, I usually check the article summary to get an overview."●Political Article:"The political article discussed the implications of recent policy changes."●In-depth Article:"The website offers in-depth articles on topics ranging from science to culture."●Research Article:"The academic journal published a research article on the effects of climate change."●Article Title:"The article title caught my attention, and I decided to read the full piece."这些短语搭配可以帮助你更具体地表达与"article" 相关的不同情境和语境。

把文章发给杂志的英语作文

把文章发给杂志的英语作文Submitting an Article to a Magazine。

As a writer, one of the most exciting and rewarding experiences is having your work published in a magazine. Whether you are a seasoned writer or a newcomer to the world of publishing, submitting an article to a magazine can be a daunting task. However, with the right approach and a well-crafted piece, you can increase your chances of getting your work noticed and ultimately published.The first step in submitting an article to a magazineis to research potential publications that would be a good fit for your work. Consider the genre, style, and audience of the magazine, and make sure that your article aligns with their editorial focus. It's also important to familiarize yourself with the submission guidelines of each magazine, as these can vary widely and may include specific formatting requirements, word count limits, and submission deadlines.Once you have identified a few magazines that you would like to submit your article to, it's time to prepare your submission package. This typically includes a cover letter, a brief author bio, and of course, your article. Your cover letter should be professional and concise, introducing yourself and your article, and explaining why you believeit would be a good fit for the magazine. Your author bio should highlight your relevant experience andqualifications as a writer, and it's also a good idea to include any previous publications or awards.When it comes to your article, it's important to ensure that it is polished and well-written. Take the time to carefully proofread and edit your work, and consider seeking feedback from a trusted colleague or mentor. Pay attention to the magazine's style and tone, and tailor your article to fit their editorial preferences. If the magazine has a specific theme or topic for an upcoming issue, be sure to mention how your article relates to it in your cover letter.After you have prepared your submission package, it's time to send it off to the magazines you have chosen. Be sure to follow their submission guidelines closely, whether that means sending your materials via email or through an online submission portal. Keep in mind that response times can vary widely, so it's important to be patient and wait for a reply. If you haven't heard back after a reasonable amount of time, it's acceptable to follow up with the magazine to inquire about the status of your submission.If your article is accepted for publication, congratulations! You can look forward to seeing your workin print and sharing it with a wider audience. If your article is not accepted, don't be discouraged. Rejection is a common part of the writing process, and it's important to remember that it doesn't necessarily reflect the quality of your work. Take any feedback you receive to heart, and use it as an opportunity to improve and refine your writing for future submissions.In conclusion, submitting an article to a magazine can be a challenging but ultimately rewarding experience forwriters. By researching potential publications, preparing a strong submission package, and following up as needed, you can increase your chances of getting your work noticed and ultimately published. Remember to stay persistent and resilient in the face of rejection, and keep honing your craft as you continue to pursue opportunities for publication. Good luck!。

documentclass{article}用法

中文文章写作常用的格式为非Markdown格式的普通文本撰写。

在写作之前，需要了解如何使用documentclass{article}。

具体用法如下：1. documentclass{article}是LaTeX文档类之一，用于创建文章类文档。

2. 在使用documentclass{article}之前，需要在文档的开头使用\documentclass{article}命令来声明文档的类型。

例如：```\documentclass{article}```3. documentclass{article}提供了一些选项，可以在声明文档类型时进行设置，如：- 选择文档的总体字体大小：\documentclass[11pt]{article}表示选择11磅的字体大小。

- 选择单双面打印：\documentclass[twoside]{article}表示选择双面打印。

- 选择页面尺寸：\documentclass[a4paper]{article}表示选择A4纸张大小。

4. 使用documentclass{article}后，需要在文档中使用\begin{document}和\end{document}命令来声明文档的正文内容，例如：```\begin{document}正文内容\end{document}```5. 在documentclass{article}中，可以使用一些常用的命令和环境来排版文章，如：- 使用\title{}、\author{}和\date{}命令来添加文章的标题、作者和日期。

- 使用\maketitle命令来生成标题。

- 使用\section{}、\subsection{}和\subsubsection{}命令来添加文章的章节和子章节标题。

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Energy conservation measures in an institutional building in sub-tropical climate in AustraliaM.M.Rahman,M.G.Rasul *,M.M.K.KhanSchool of Engineering and Built Environment,Faculty of Sciences,Engineering and Health,Central Queensland University,Rockhampton,Queensland 4702,Australiaa r t i c l e i n f o Article history:Received 7May 2009Received in revised form 8March 2010Accepted 4April 2010Available online 6May 2010Keywords:Eenergy conservation measures Hot-humid climate DesignBuilderBuilding energy simulation Thermal comfort index Building energy analysisa b s t r a c tIn this study,various energy conservation measures (ECMs)on heating,ventilating and air conditioning (HVAC)and lighting systems for a four-storied institutional building in sub-tropical (hot and humid cli-mate)Queensland,Australia are evaluated using the simulation software called DesignBuilder (DB).Base case scenario of energy consumption proﬁles of existing systems are analysed and simulated ﬁrst then,the simulated results are veriﬁed by on-site measured data.Three categories of ECMs,namely major investment ECMs (variable air volume (VAV)systems against constant air volume (CAV);and low coef-ﬁcient of performance (COP)chillers against high COP chillers);minor investment ECMs (photo electric dimming control system against general lighting,and double glazed low emittance windows against single-glazed windows)and zero investment ECMs (reset heating and cooling set point temperatures)are evaluated.It is found that the building considered in this study can save up to 41.87%energy without compromising occupancies thermal comfort by implementing the above mentioned ECMs into the existing system.Ó2010Elsevier Ltd.All rights reserved.1.IntroductionEnergy conservation in building is the practice of saving energy use without compromising occupant thermal comfort.ECMs often provide better indoor air quality (IAQ)and enhance occupancies productivity [1,2].However,a cost penalty is experienced if poor IAQ is traded for reduced energy consumption [3].Building sectors are responsible for approximately 42%of the world’s total annual energy consumption [4].Most of this energy is used for the provi-sion of lighting,HVAC systems and electricity based ofﬁce appli-ances [5].In Australia 70%of the end use energy consumption in non-residential buildings is devoted to HVAC and 15%to lighting [6].Buildings in the developed countries account for 50–60%of electricity use [7,8].Of the energy used for space conditioning,65%is in the form of electricity [9].Studies have reported that en-ergy savings of up to 30%can be achieved through retroﬁt options in existing ofﬁce and commercial buildings without compromising the indoor comfort [10–14].The operating costs of a building could be improved if the lighting and HVAC system of the building can be made more energy efﬁcient.This study focuses on the various ECMs that could potentially be implemented at any region in Australia.The objective of this study is to investigate the opportunities for ECMs in institutional build-ings in hot and humid climates in Australia.A case study is con-ducted on a four-storied building system at Central Queensland University,in a sub-tropical climate Rockhampton,Australia.Dif-ferent types of feasible and practical operational ECMs such as ma-jor investment measures (VAV systems against CAV,and low COP chillers against high COP chillers),minor investment measures (photo electric dimming control system against general lighting,and double glazed low emittance windows against single-glazed windows)and zero investment measures (reset heating and cooling set point temperatures),are evaluated using DesignBuilder (DB),a graphic user interface based building energy simulation tool [15].DB’s calculation method is based on EnergyPlus (EP)simulation en-gine [16].The results of the simulation are veriﬁed with measured energy consumption proﬁle for base model.Then,the simulation is performed for different ECMs and their results are analysed,dis-cussed and presented.Thermal performance of these ECMs strate-gies are also evaluated and veriﬁed by thermal comfort index.2.Building and system descriptionThe information technology division (ITD)building,a four-story university building was used for this case study (Fig.1).The build-ing is located in Rockhampton campus of Central Queensland Uni-versity (CQU),Australia at latitude 23.4°S and longitude 150.5°E.Its orientation is 75m in the east–west direction and 45m in the north–south direction (345°N).The major energy consumers of this building are the air conditioning system,lighting system and ofﬁce equipment.In order to analyse different end user energy consump-0306-2619/$-see front matter Ó2010Elsevier Ltd.All rights reserved.doi:10.1016/j.apenergy.2010.04.005*Corresponding author.Fax:+61749309382.E-mail address:m.rasul@.au (M.G.Rasul).tion and their categories,the real time (actual)data were collected from January 2007to December 2007.The speciﬁcations of the system/equipment,category,operating hours and energy use are given in Table 1.Data and information on geometrical conﬁguration,construction materials,internal loads including occupied/un-occupied loads during day time and after –hours (employee,ofﬁce equipment,lighting systems and cooling loads),operating schedules including occupancy and after-hour schedules,MVAC (mechanical ventilating air conditioning)system equipment and operation hours were collected for assessment of building energy performance.The building has complete air conditioned ﬂoor area of 4260m 2and ﬂoor-to-ﬂoor height of 4.2m.The Building has a fairly stan-dard construction,with light weight 130mm concrete ﬂoor slabs,single-glazed conventional external walls (40%)with blind,light weight 100mm cavity brick partition wall covered with 2Â15mm 2gypsum board,suspended type 15mm ceiling tiles.Occupancy rate is 10m 2/person with 10L/s outside air rate.The lighting system serving the building is mainly of regular 40W dou-ble ﬂuorescent lamps.The HVAC systems used in the building is constant air volume (CAV)with 17air-handling units (AHUs)serv-ing the different zones of the building.The cooling of the building is provided by chilled water from the plant through two reciprocat-ing air cooled chillers.Each chiller has a maximum total capacity of 420kW and supplies 13L/s at leaving water at 7°C with a return air temperature of 12°C.The mean coefﬁcient of performance (COP)of chiller was 3.8.Both chillers are controlled by the cooling demand of the AHUs.Each ﬂoor has separate thermostat control with zone set points between 23.5°C to 24°C for summer (Decem-ber –February)and 21.5°C to 22°C for winter (June–August).The buildings were occupied from 7am to 6pm Monday–Friday.The physical characteristics of base model building are given in Table 2.2.1.Base model developmentDesignBuilder (DB)is one of the most comprehensive user interfaces for EnergyPlus (EP)dynamic thermal simulation engine.DB joins the software EP calculation model and maintained the EPBD (European Parliament Board of Directive)standards [18].EP is tightly integrated into DB environment to generate detailed building energy performance data by simulation using real (mea-sured or bureau of meteorology (BOM)data)weather data.The simulation principle used by DB is the most detailed simulation with dynamic parameters and they include all energy supply and energy dispersion.EP on the other hand uses a modular program structure,which makes the calculation method easy to understand.The EP solution is based on the heat balance technique referredtoTable 1ITD building system’s average end use details.System/equipment Detail category Operating hours Energy use (W/m 2)Cooling system Air-cooled 7:00–18:00extended 24Â7for some area 45Ventilation system Standard a 7:00–18:005LightingFluorescent 7:00–22:0015Ofﬁce equipmentStandard a7:00–18:0015aBCA 2006[17].Table 2Physical characteristics of base model building.Characteristic/component Description for base modelLocationCentral Queensland,Australia (latitude 23°40S and longitude 150°50E)Type of building &shape Four stories,University Academic Building,L -shape Total height16.8mFloor dimensions 75m Â45m Â10m Â10m Â35m Â30m Gross ﬂoor area 4260m 2(ceramic tiles and synthetic carpet)External wallStucco 25mm,medium weight concrete block 200mm,wall membrane,medium weight concrete block 200mm,plaster 19mm.Light colored (U )=2.005W/m 2KInternal ﬂoors 50mm Screening,150mm light weight concrete,ceiling void and 19mm ceiling panel U -value =0.599W/m 2K Internal core wall 19mm Plaster,200mm medium weight concrete and 19mm plaster U -value =1.930W/m 2KInternalpartitions 16-mm Gypsum board,25mm airspace and 16mm gypsum board.U -value =1.680W/m 2KRoofGravel,roof wood framing W/R-49,Polyurethane expanded 50mm,roof wood framing W/R-49,roof membrane,heavy weight un-dried aggregate 100mm,(U )=0.539W/m 2KGlazingSingle pane,single clear/no shading 6mm,(U )=6.121W/m 2K,total solar transmission(SHGC)=0.81,direct solar transmission 0.775,light transmission =0.881Number of occupants 478(Maximum)Lighting15W/m 2Type of lighting Fluorescent Equipment 15W/m 2HVAC system Constant air volume,total no.of AHU’s =17,each AHU power ratings =7.6kW,no.of zones =24ChillersType =reciprocating,capacity =747.2kW refrigeration,no.of chillers =2,supply water temperature =6.5°C,return water temperature =13°C,refrigerant ﬂow =13.6L/s Ventilation rate 10.0L/s/person Inﬁltration rate 0.2ACHSet pointtemperature23À24°C in summer (December–February)22À23°C in winter (June–August)as the Predictor–Corrector Method[19]and assumes that the room air is well stirred,providing a uniform temperature.The basic strategy behind the Predictor–Corrector Method is to predict the mechanical system load needed to maintain the zone air set point, and then simulate the mechanical systems to determine their ac-tual capacity,and then recalculate the zone air heat balance to determine the actual zone temperature.DB models were structured in order of building site,block,zoneand surface data.This structure sets up data globally in a building model.Building blocks are basic geometric shapes that are used to assemble a3D model similar to the actual building model made of bricks.In the modelling,building blocks were considered as com-posed of building elements such as walls,ﬂoor slabs and roofs, and are partitioned internally to form thermal zones.The partition of the space boundaries of the thermal zones were modelled according to the HVAC drawing.The whole building energy simu-lation was performed using data from the nearest available hourly weather station(Rockhampton Airport).The DB user interface with 3D view of the reference ITD building is shown in Fig.2.For eachwere used in this building.For validating the base model,data were collected from the building energy management system (BMS)(METASYS building automation system),HOBO data loggers and Smart Meters which were manufactured by EDMI Pty Ltd[22]. Smart meters were installed to measure the characteristics of the daily electrical load,demand and energy consumption in HVAC system,lighting and miscellaneous separately.Pieces of monitor-ing equipment were placed in the main electrical switch rooms to monitor the building mechanical system.The HOBO Data Log-gers instruments were used to measure air temperature and humidity.The HOBO Energy Pro Loggers(modular,reconﬁgurable Table3ASHRAE standard for equipments[20].Name of equipment Wattage rating(W) Monitor70Printer400Copier11002996M.M.Rahman et al./Applied Energy87(2010)2994–3004integrated together for the purpose of estimating the building en-ergy performance.Either hourly or monthly data can be employed for validation[23].Kaplan and Canner[24]made recommenda-tions for the allowable difference between predicted and measured (actual)data.For instance,the prediction of energy use is consid-ered satisfactory when the difference is within5%on a monthly ba-sis and15%on a daily basis for internal loads such as lighting, appliances or domestic hot water system.However,the acceptable difference may increase up to15–25%monthly and25–35%daily for the simulation of HVAC systems.The annual simulated energy use should be within10%of metered data,while a difference of less than25%is acceptable on a seasonal basis.The capacity of DB is not only to predict zone loads,cooling coil loads and cooling equip-ment energy consumption but also to predict zone environmental parameters such as temperature,humidity,etc.[24].In this computational simulation process,three parameters were considered for base model validation.They are internal aver-age hourly temperature,average hourly relative humidity and aver-age hourly total energy consumption of a typical winter day(June–August)and summer day(December–February).Measured average hourly indoor air temperature data of a typical winter working day (29/6/2007)and summer working day(27/1/2007)are compared with DB simulated data in Fig.3a for winter and b for summer respectively.It is found from Fig.3that the measured data varies within7%of the simulated data for both in winter and summer.Measured average hourly indoor air humidity data of same win-ter day(29/6/2007)and summer day(27/1/2007)are compared with DB simulated data in Fig.4a winter and b summer,respec-tively.The variation between predicted and measured humidity data are found within9%in winter and11%in summer day.Fig.5compares the simulated and measured(actual)energy consumption data of same working day in winter and summer. The measured data varies within11%of the simulated data in win-ter and9%in summer day respectively.Simulated results of monthly energy consumption over the year of HVAC system,lighting system and ofﬁce equipment are com-pared with the measured data in Fig.6.It is found from Fig.6that the measured energy consumption is within9%of the simulated energy consumption.This demonstrates that the DB predictions are in good agreement with the data collected by the BMS,HOBO data loggers and smart meters in ITD building.Hence,it can be as-sumed that the modelled ITD virtual building is capable of produc-ing approximately the actual operating condition of the existing ITD building.Thus this modelling and simulation technique can be used for the evaluation of different energy conservation mea-sures and their energy performance analysis.3.Evaluation of ECMsAn evaluation was performed from the baseline model to estab-lish the potential of energy savings in the building.The energy con-sumption breakdown for modelled building is shown in Fig.7.It can be seen from Fig.7that the largest amount of energy(48.34%)is con-sumed by the ofﬁce appliances while HVAC system(AHUs and chill-ers)consumes32.51%(chillers25.76%and AHU and miscellaneous 6.75%)and lighting system consumes19.15%.Ofﬁce appliances con-sumes highest energy because there were several computer labora-tories(each contains about100personal computers),many small and large printers,Xerox machines,scanners,etc.which(each)con-sumes a large amount of energy.On the other hand,the next highest energy consuming item was HVAC systems which consisted of con-stant air volume(CAV)air conditioning system with17air-handling units(AHUs)serving the different zones of the building.The cooling of the building was provided by chilled water from the plant through two reciprocating air cooled chillers.Each of these items consumes a signiﬁcant amount of rmation on HVAC systems,AHUs and chillers was collected from design data,equipment tags,as well as the information provided by the building maintenance personnel. Although there were hundreds of lights of different types,the whole lighting systems consumed least amount of energy because as each of the lights only consume a little energy.The retroﬁt options are investigated for only HVAC system and lighting system of the build-ing.Several ECMs are analysed and evaluated based on the seasonal energy use pattern of the building without compromising occupant thermal comfort.Based on economic interest,the ECM can be grouped into three categories such as major investment,minor investment and zero investment measures.These three categories of ECM are deﬁned as follows.Major investment measures require a considerable amount of investment to be made for the implementation of new strategies. These measures can be implemented through system renovation, or retroﬁtting of the existing buildings.Consequently,these ECM require wise judgments and comparison between the investment input,the saving being attained and the pay back period before theirﬁnal consideration for implementations.Minor investment measures are measures that can be implemented for building alter-ations or modiﬁcations and thus,minor cost is required for their implementation.Zero investment measures do not require any investment or modiﬁcation to be done in the existing system or the facility.It simply requires detailed study of the HVAC system’s operation so that the operation of the HVAC system without com-promising occupants’thermal comfort can be optimised.ECMs analysis and evaluation were done for all investment cat-egories mentioned above.These are presented and discussed below.Table4Details of building lighting,equipment and people.Floor name Zone name Equipmentpower(EPD)W/m2Lighting powerdensity(LPD)W/m2Number ofoccupants aGround Computer lab1352035Computer lab2352035Computer lab3352040Post grad lab1302020Post grad Lab2302020Help desk115153Lecture gallery1202550Maintenance lab20258First Post grad lab3302020Post grad lab4302020Photocopy room140152Meeting room1152010Meeting room2152010Ofﬁce room1202012Ofﬁce room2202012Help desk115153Second Post grad lab3302020Post grad lab4302020Photo copy room140152Meeting room1152010Meeting room1152010Ofﬁce room1202012Ofﬁce room2202012Help desk115153Third Post grad lab3302020Post grad lab4302020Photocopy room140152Meeting room1152010Meeting room2152010Ofﬁce room1202012Ofﬁce room2202012Help desk115153a Maximum no.of occupancy counted from building management occupancyschedule.M.M.Rahman et al./Applied Energy87(2010)2994–300429973.1.Major investment measures3.1.1.VAV system against CAV systemIn the CAV system,all AHUs fans operate with constant speed. They supply conditioned air through a constant volume air supply system to the conditioned zones.The system is designed to supply enough air to cool the building under design conditions.As an ECM, changing the system to a VAV system reduces the amount of air supply by all AHUs as a function of zone load and normally results in less energy to condition the various zones.There are three types of VAV systems.They are VAV with terminal reheat,VAV with fan-assisted terminal reheat and VAV with outside air reset.All of these systems are designed around the VAV philosophy with load diver-sity,low turndown ratios,high efﬁciency/low running costs,use of free cooling,normal or low temperature air and zero maintenance. Each terminal unit is eligible toﬁt with any building management system.These all air systems can provide the most energy efﬁcient method of providing fresh air and high cooling/heating load set point options with close control opportunity of up to0.5°C for medium to large sized buildings.Fig.8compares the energy use between base model and various VAV systems.It can be found from Fig.8that an average monthly energy savings of about 3.6%,15.1%and16.9%can be achieved by VAV with terminal re-heat,VAV with fan-assisted terminal reheat and VAV with outside air reset respectively.3.1.2.More energy efﬁcient reciprocating chillersChillers are the main part of HVAC systems and play an important role in energy consumption and demand.In the base model building,air cooled reciprocating chillers with coefﬁcient of performance(COP)of3.8are used.More energy efﬁcient air cooled reciprocating chillers with higher coefﬁcient of perfor-mance(COP of4.80)are considered for evaluation as an ECM. An annual energy saving of about9.96%can be achieved using more efﬁcient reciprocating chillers with COP of 4.80(Fig.9). The input data for this simulation were based on the speciﬁca-tions obtained from manufacturer’s catalogue of the Carrier Air-Conditioning Company[25].The Carrier Air-Conditioning Com-pany manufactures all kinds of chillers throughout the world, and Australia is one of the biggest consumers.This ECM might be feasible to apply to the existing building when the retroﬁtting of existing systems is deemed necessary and can also be applied to similar types of ofﬁce buildings which are in the design stage or under construction.3.2.Minor investment measures3.2.1.Energy efﬁcient light and daylightingSigniﬁcant amount of energy savings can be achieved if day-lighting can be integrated with electic-lighting[26,27].One of the strategies of energy efﬁcient building design is theinclusionof daylighting and/or the natural lighting into the building design which is an important and useful strategy in terms of visual com-fort,energy conservations and light controls[28–32].For a typical ofﬁce building lighting represents about40%of the total electrical energy use[33].In Australia,about21%of electrical energy is used for lighting in ofﬁce buildings[34]whereas about18%of total elec-trical energy is consumed for lighting in case study ITD building [5].There are a variety of simple and inexpensive measures to im-prove the efﬁciency of lighting systems.These ECMs include the use of energy efﬁcient lighting lamps and dimming control ballasts. Currently,for the case study building,40Wﬂuorescent lamps are being used.As an ECM,energy efﬁcientﬂuorescent lamps with the power of34W and three different dimming control strategies namely T8ﬂuorescent-triphosphor with(1)linear,(2)stepped and(3)on/off dimming day lighting control were considered for simulation.The authors acknowledges that although T5lampﬁt-tings could be considered for ECM,however the simulation was done using T8lamp because of the facilities management of the host university wanted to replace T12with T8as T8was widely available during the period of this study.Fig.10compares the sim-ulation results of monthly total energy consumption by various daylighting control systems with energy efﬁcient T8lamps instead of T12low efﬁcientﬂuorescent lamps with the base model.It can be found from Fig.10that on an average monthly savings of about 4.63%,4.71%and4.63%can be achieved by linear,stepped and on/ off dimming daylighting control systems respectively.It is noted that the stepped dimming control along with T8ﬂuorescent-tri-phosphor lamp can achieve near to maximum energy savings. The lamp life of the stepped dimming control system is longer than the linear dimming lighting control system.Although average en-ergy savings among those daylighting controls are nearly the same, the longer life of stepped dimming control over other daylighting dimming control makes it(stepped dimming control)a more appropriate candidate for ECM.3.2.2.More energy efﬁcient glazing systemUsing more energy efﬁcient windows(high R-value,low emis-sivity glazing,air tight)can be beneﬁcial in both reducing the en-ergy use and improving the indoor comfort levels.Nowadays,a multiple glazing window system is used.Double-glazing is simply deﬁned as two panes of glass with a layer of air or gas between each pane of glass.Triple glazing has three panes of glass with sealed spaces of ideally12mm in between.The precipitating factor for renovation of single-glazed windows into double glazing or tri-ple glazing is to conform to modern energy standards because of the lack of modern energy standards in single-glazed windows. The main advantage multiple glazing offers over traditional win-dows is insulation.Well-made and well-ﬁtted double glazing can reduce cooling and heating costs by as much as5–10%and even more depending on the amount of glass used in the facilities be-cause nearly25%of indoor heat is lost through windows[35]. For the existing building,single-glazed windows are usedwith Measured vs.simulated indoor air humidity;(a)for a typical winter day(29/6/2007),(b)for a typical summer daythe U -value of about 6.1W/m 2C.The total solar transmission is 0.81and direct solar transmission is 0.775for the base case.As an energy conservation measure,the existing glazing system was tested with low emittance double glazed and triple glazed win-dows.Details are provided in Table 5.The results of monthly total energy consumption for use of low emittance double and triple glazed windows are shown in Fig.11.It can be found from Fig.11that on an average,about 7.31%and4.04%energy savings can be achieved by double and triple glazed ECM respectively.Triple glazing can not gain maximum proﬁt be-cause triple glazing achieved less energy savings (Fig.11)and the triple glazing require more renovation expenses compared to the double glazing system.Hence,the double glazing system can be recommended for ECM for this case study building and similar type of ofﬁce buildings with large glass opening areas.3.3.Zero investment measures:set point temperature change for cooling and heatingThe impact of indoor temperature settings on energy use is ana-lysed.For the base model,the cooling temperature was set at 23°CAppliances AHU&Misc 25.76%for the whole year.In this ECM,different temperature set points are evaluated.Initially the set point temperature was set at25°C to achieve desired temperature during daytime but the indoor temperature was exceeding the deﬁned comfort limits.Therefore,the temperature set point was reduced to24°C taking into consid-eration occupants’comfort for moderate activity.This selected temperature set point lies within the comfort zones of the two different seasons.This ECM by resetting cooling temperature atparison of monthly energy use between base model and high COP chillers.parison of monthly energy consumption among base model and various daylighting control systems.24°C has generated cumulative energy saving of about 29,145kW h in a year for the whole building.It is equivalent to 1.96%savings of total annual energy consumption.Similarly,by resetting heating set point at19°C instead of 20°C about15,280kW h cumulative energy savings can be achieved for the whole year which is equivalent to1.03%of an-nual energy consumption.Cooling reset ECM has gained approx-imately double saving compare to heating reset ECM because the winter season lasts for only on an average4months in a calendar year in bined energy savings by ECMsThe energy savings discussed in previous sections are summa-rised in Table6.A total of41.87%energy savings can be achieved by implementing all the above discussed ECMs.Every candidate of ECM was evaluated on the basis of effective energy consumption without compromising indoor thermal comfort.Authors consid-ered ECM of each category separately,because,for many organiza-tions they may not be able to implement all types of ECMs together.It is better for them to know each ECM separately so that they can implement some of them according to their ability. Authors believe that there could be some variation if all ECMs were considered together for modelling.However,further study is rec-ommended to assess energy saving using all ECMs together.4.Thermal comfort indexTo determine appropriate thermal conditions,practitioners re-fer to standards such as ASHRAE Standard55[36]and ISO Standard 7730[37].These standards deﬁne temperature ranges that should result in thermal satisfaction for at least80%of occupants in a space.The standards were developed by Fanger and colleagues on the basis of laboratory studies of whole body thermal comfort, known as the Predicted Mean Vote(PMV)model[38].The seven point ASHRAE thermal sensation scale is given in Table7.The PMV model combines four physical variables(air temperature, air velocity,mean radiant temperature,and relative humidity) and two personal variables(clothing insulation and activity level) into an index that can be used to predict thermal comfort.Fanger’s mathematical model of PMV is expressed in Eq.(1) [38],PMV¼ð0:303eÀ0:036Mþ0:028ÞÂLð1ÞTable6Details of ECMs based on investment and their annual savings.Level of investment ECMs Description Resultantsavings(%)Zero investment Change inthermostat setpoint From23°C to24°C forcooling all days of the year.1.96 From20°C to19°C forheating all days of the year1.03Minor investment Daylighting T8ﬂuorescent-triphosphor–with LINEAR dimmingdaylighting control14189294.62T8ﬂuorescent-triphosphor–with STEPPED dimmingdaylighting control14176244.71T8ﬂuorescent-triphosphor–with on/off dimmingdaylighting control14187634.63More efﬁcient glazing system Double glazing,clear,internal blinds13789357.31 Triple glazing,clear,noshading14275844.04Major investment Replacementof CAV to VAVof HVACsystem VAV with terminal reheat 3.58 VAV with fan-assistedterminal reheat15.05 VAV with outside air reset16.9Replacement of low COP chillers to high COP chillers9.96 Total from all highlighted41.87Table7ASHRAE seven point thermal scale.Cold Cool Slightly cool Neutral Slightly warm Warm Hot À3À2À101233002M.M.Rahman et al./Applied Energy87(2010)2994–3004。