外文翻译示例
外文资料译文
CliffhangerLawrenceHargrave路是Wollongong北部一条沿海的路，它是澳洲，New South Wales 风景最优美的路之一, 并且是一个主要的旅游胜地。
路的一个900m截面并且是路的最高的倾斜风险部分在整个国家, 由于岩石掉落和堤防失败的悠久历史。
Richard High报告关于一条壮观的供选择的路线的建筑。
修造在19 世纪60 年代路直到1947 年才作为更低的沿海路被人们知道, 当这改名劳为Lawrence Hargrave Drive (LHD) 。
出生在格林威治，英国在1850年，Lawrence Hargrave 是航空先驱,发明者, 探险家, 泥工和天文学家。
1984年, 他成为了第一人在澳洲飞行,在附近的Stanwell公园。
并且安排沿海路改名以纪念他。
Hargrave 的面孔首先出现在AU$20笔记, 1966年发布。
最初,土轨道,LHD许多年中运载了比较少量的车辆。
在21 世纪作为地方社区和旅游业增长, 大约每天3000辆车在路上行驶。
在2003年8月,随着一项独立研究,发现了路对于公共安全形成了“不可抵御的风险”,负责认为路宣布了一个大修项目为LHD。
在2003年11月,为了加速建筑和压低费用，公路和交通当局(RTA)形成了建筑联盟——Lawrence・Hargrave驱动联盟(LHDA)，与Barclay・Mowlem, Coffey Geosciences和Maunsell Austrlia。
建筑在2004年6月开始在AU$ 4900 m 部分的百万(US$ 37 百万)替换在Clifton 和Coalcliff 之间。
并且路预计在2006 年的早期通车。
在项目中心是二座桥梁, 你跨过南部的海湾和其他中间陆岬, 将连接形成一座唯一665 m 长的桥梁。
路线然后将回到现有的对准线通过北海湾。
新路, 包括桥梁, 将有两个3.5 米宽的车道, 一个是双车道, 1米宽路肩。
外文翻译(英文)
外文文献Gold refining technology introductionGold ore in the content is extremely low, in order to extract gold, need to will be broken and fine grinding ore and adopt。
With the mineral processing or enrichment from ore in advance that gold is isolated. Gold ore dressing is used in moreRe-election and flotation, re-election method in ShaJin production in an important position, flotation method is rock gold mine。
Widely use of mineral processing mountain, at present our country about 80% of the rock gold mines use this law to choose gold, choose。
Ore technology and equipment level is distinctly improved.(A) Broken and grindingAccording to the survey, our country choose gold in the jaw crusher for crushing, using standard cone broken. Ore machine broken, and finely used the short head type tapered roller machine and broken mine to break mine machine. Medium and small choose.Gold factory is used mostly for two broken a closed-circuit ore, large choose the three sections of a gold factory closed-circuit broken mine process. In order to improve the dressing production ability, mining equipment potential, broken mine to process, the reform.Grinding machine utilization coefficient increase, the major measures taken the little mill is broken, reduce ore into the ground particle size.(B) Re-electionRe-election in rock gold mine apply more extensive, and more as aided process, in the grinding loop of the recovery. Coarse grain of gold, for flotation and cyanide process to create favorable conditions, improve concentration index, improve the total return to gold. The yield, to increase production and reduce the cost is playing a positive role. Shandong province about more than 10 pick. Gold factory used heavy choose this one process, the average total recovery can be increased 2% ~ 3%, the enterprise economic effectGood profit, according to not complete count, may have millions of dollars a year of the profits. Henan, hunan, Inner Mongolia, etc. Provinces (areas) also have good effect, the main equipment is chute, wave bed, jig and short cone. Vortex machines etc. From our mostgold mine to see, float-heavy joint process (flotation tailings used heavy Choose) suitable for.(C) FlotationAccording to the survey, 80% of rock in the gold mines flotation method selected gold, the output of the concentrate more. Sent to non-ferrous smelter processing. Because of leaching gold cyanide process of development and enterprise to improve economic efficiency. Good, reduce concentrate transportation loss, in recent years the product structure has experienced a greater change, take more local processing (of course also because of mineral smelting and the contradiction between the problems and valuation, forcing the mine in situ to place Richard) prompted the flotation process have larger development, in the gold production occupies an important position in the. Usually Priority of flotation and mixing floatation two craft. In recent years in the process modification and potions add system .With new progress, flotation recoveries also increased significantly. More than 40 selected according to the national gold factory, flotation work.(D) The choose-leaching gold technology sector1. Mix mercury law of leaching goldMix mercury method of leaching gold process is a kind of old mention gold process, easy, and economic, and is suitable for coarse grains. Monomer recovery of gold. Our country many gold mine still follow the method. Along with the development of the gold production and the progress of science and technology, mix mercury law of leaching gold process is also constantly have improved and perfected. Due to the environment.The increasingly strict requirements, some mining cancelled mix mercury assignments, as heavy choose, the flotation and cyanide process of leaching gold.process replaced. In the gold production, mixed mercury method of leaching gold technology still has its important role in the domestic and foreign are should be with a practical example. At present in zhangjiakou, hebei province, liaoning erdaogou, jilin jiapigou, shandong etc many gold incorporated. Mine the process application. Liaoning erdaogou gold mine was a single flotation process, according to the ore properties instead.2. Of leaching gold cyanide process technologyCyanide process technology of leaching gold from oreconcentrate is modern or extraction of the main method of gold. Cyanide process mention.Gold technologies include: by roasting-cyanide leaching process, leaching of pulp washing filtering, kau liquid or are the cicc pulp.The extraction and the finished product and so on several basic processes of smelting. China's gold mines are the two basic existing factory. Kind of leaching gold process, one kind is dense continuous against washing machine, with zinc powder replacement precipitation back. The gold of so-called ordinary cyanide process of leaching gold process (CCD method and CCF law), the other is without filter washing, the active carbon adsorption in the pulp are directly from the recovery of gold without filter are carbon plasma process (CIP method and CIL law).Ordinary cyanide process of leaching gold process according to the different materials handled and two .(E) Heap leaching process for productionGold resources in China, low grade oxidation of ore has certain proportion, deal with this kind of ore.The routine of leaching gold cyanide process technology not economically viable, and the production process heap leaching, there are economic effect. The victims. Further expand the production scale heap leaching, is increase China's gold production of one of the path.20. At the end of the 70 s, China began to low grade contain gold ore heap leaching oxidation of the production process research, liaoning dandong hushan gold small-scale production trials are successful, successively in henan spirit lake, silver Hole slope, yunnan MoJiang, hebei worship ritual, Inner Mongolia and some of the mine in chifeng application, take more satisfactory economic effect, low grade for the gold ore containing the oxidation of the development and utilization of the opened up.。
5外文翻译模板(示例)
毕业设计(论文)外文资料翻译学 院： (用三号楷体，下同） 专 业： 姓 名： 学 号： 外文出处：附 件： 外文原文（复印件）(用外文写)译文标题（三号黑体，居中，单倍行距，段前0.5行；段后1行。
）ZUO Zheyi ,ZUO Zheer (四号Times New Roman ，行距20磅)(School of Electrical Engineering, Northeast Electric Power University, Jilin 132012, Jilin Province, China) （五号TimesNew Roman ，行距18磅，居中，段后0.5行，作者简介不用翻译成中文）摘要：(小四宋体，加粗) 文章摘要，要反映文章主要的技术内容，如研究目的、方法阐述和具体结论，阐明文章的行文脉络及文章的重点即可。
说明文章主要内容是什么，分哪几个部分介绍的，最后客观阐述结论或试验结果，不要有个人对研究结果的主观评价和研究背景介绍。
(小四号宋体，1.5倍行距，两端对齐)关键词：(小四宋体，加粗)油水两相流；经验模式分解；Elman 神经网络 (小四号宋体) 1 一级标题一（小四宋体，加粗，1.5倍行距，段前段后各0.5行） 1.1二级标题（小四宋体，加粗，1.5倍行距，段前段后各0.25行）正文×××××（小四号宋体，1.5倍行距）××…………。
（要求3000～5000汉字） 正文中的公式。
221()mi i ij j E c t dt c ===∑⎰ (1)其中，ij c ( i =1,2,…,n ，j =1,2,…,m)表示IMF 的离散点的幅值，m 为信号采样点的数目。
（公式中涉及的字母所代表的物理量要全部指明。
公式所在行单倍行距，右对齐，符号大小在公式编辑器中尺寸栏中的“define ”下的“full ”项选12，其他默认）1.2 二级标题正文中的图。
2应用文翻译例子
应用文例子1. Dear Sir,We wish to draw your attention to the result of inspection made by CCIB Shanghai of the consignment of sulphur under Contract No. OXHJ73091 MC Shipped per s. s. “Sanming” and discharged at Shanghai:purity: 99.81% which is 0.09% lower than 99.9%stipulated in the contract;acidity: 0.066% which is 0.056% higher than the contracted 0.01%;hydrocarbon: 0.101% which is higher by 0.031% than 0.075% as stipulated in the contract.On the strength of the Inspection Certificate No. 221003 in one original and the Freight Account enclosed herewith we file a claim against you for the following amounts:1. goods value on FOB basis: US $ 2046.002. freight: 805.783. insurance premium: 9.154. inspection fee: 2720.60total US $ 5,581.53If you do not challenge the claim after your certification please credit by remittance the said total amount in compensation to our account at the Bank of China, Beijing.Yours faithfully(signature)先生：OXHJ73091 MC合同项目下的硫磺由SANMING轮运卸上海，希望贵方能对中国上海进出口商品检验局检验的结果予以重视。
外文译文范例
外文资料Rural Labor Movements in Egypt and Their Impact onthe State, 1961-1992Looney, RobertJames Toth's highly informative study of Egypt develops the idea that the tarahil or migrant farm workers in Egypt unexpectedly contributed to the making of Egypt's recent history and in shaping the country's national development. His arguments are developed by first examining the struggles taking place inside the rural regime of accumulation and the methods of control each side employed to regulate conflicts over pay and working conditions. This involves not only describing the workers' way of life, standard of living, and the labor processes in both village agriculture and migrant labor, but also identifying the asymmetric relationships and negotiations involved in mutually defining the effort price formula.Toth demonstrates how initially these institutional relations remained local since direct state intervention was relatively limited before the 1960s. Once the state did step in, however, local conflicts diminished while the struggles between workers and their government acquired greater importance. State policies formulated since 1960 repeatedly altered the equation between labor and capital. Toth then shows that the struggle between the government and those who opposed its regulation then became an important motor force in creating Egypt's recent history.Following a carefully laid out introduction, Chapter 2 describes a composite migrant labor trip to work sites on the perimeter of Egypt's northern Delta region where the author conducted field-work in 1980-82. Here the emphasis is placed on introducing the migrant farm workers, describing the variety of social and economic relationships that keep these laborers at the bottom of Egypt's social pyramid. Chapter 3 examines why poor village farm laborers in Egypt repeatedly take up migrant work. In this section the author demonstrates that rural workers in Egypt are channeled into this occupation by the limitations imposed by seasonal unemployment, debt, gender stereotypes, and the country's economic underdevelopment. Chapter 4 develops the methods by which migrant workers exercise some control over valorization by using "weapons of the weak" and other stealth techniques, which enable them to overcome their hardship and poverty.In general, these early chapters discuss the rural regime of accumulation and the local mode of regulation found in the countryside, bridging both village agriculture and migrant labor camp activities. Toth finds these conditions replicated throughout the Egyptian countryside, both north and south. This general picture provides insights into the myriad of tactics and techniques thatregulated the valorization process at home and afar and that conditioned village lives and camp experiences. Yet despite the double-sided nature of these controls they remained insufficient to prevent first a wholesale flight of farm workers escaping the unsatisfactory conditions of village agriculture, and then later a widespread exodus that rejected the drudgery of both farm and migrant employment and seized upon new urban job opportunities that rural workers believed could improve their lives.The next sections focus on the period after 1960 when the conflicts between labor and capital ceased to have merely local consequences and began to acquire a broader, more national dimension. Chapters 5 through 8 examine the outcomes when Egypt's model of regulation came to include a greater regulatory role for the government. For in this zeal to stabilize and safeguard the national economy, the state ironically came instead to transpose and transform it.Four important years are examined: 1961, 1964, 1977 and 1992 when the course of Egyptian development was strongly influenced by the rural workers and their contentious relationship with the state. Chapters 5 and 6 analyze the outcome of the surge of rural workers who left agriculture employment behind in the 1960s and increasingly took up full-time migrant labor in building the High Dam at Aswan and reclaiming new agricultural land in Tahrir Province. Chapters 7 and 8 examine the results of the large scale movement of rural workers who later in the 1970s deserted both complementary types of employment, farm and migrant labor for similar but more rewarding construction jobs in Egypt's expanding cities and towns.Thus this section of the study focuses on decline of Egypt's agricultural and national economies, generated in good part by rural labor's physical exodus from the countryside in response to both village conflicts and state plans and projects. In 1974 the declining national economy turned around, spearheaded by skilled urban construction workers emigrating abroad who were then replaced at home by large numbers of rural laborers dissatisfied with both farm and migrant employment.Once migrant workers left both agricultural and migrant labor and moved into urban areas, they ceased to be a significant force in the countryside except insofar as their growing scarcity continued to generate production problems in the village and at migrant labor work sites. These latter chapters then focus on tarahil labor in the urban informal sector and the shantytowns to understand how their rural experience shaped their city life, and how these workers continued to affect Egypt's development. Here, further deterioration of class relations and government legitimacy aggravated by ex-rural workers who, having now migrated to the cities, nonetheless continued to be economically and politically disenfranchised.By comparing Egypt's current situation with the phases proposed by regulation theory, Toth successfully demonstrates that it has been the movements of tarahil migrant farm workers thathave significantly contributed to preventing Egypt's successful transition to cooperative peripheral Fordism. Toth's painstaking work based on years of fieldwork is a major contribution to our understanding of the dynamics of development in Egypt. It is highly recommended to anyone searching for a deeper understanding of the economic problems facing this complex country.Article source: University of Florida Press, 1999:265-268.中文译文1961-1992年埃及农村劳动力的转移及其对国家的影响罗伯特鲁尼詹姆斯关于埃及非常翔实的研究表明,埃及流动农业工人对埃及近代的历史和国家的发展做出了出人意料的贡献。
外文翻译范例
外文翻译范例在全球化日益加深的今天，外文翻译的重要性愈发凸显。
无论是学术研究、商务交流，还是文化传播，准确而流畅的外文翻译都起着至关重要的桥梁作用。
下面为大家呈现几个不同领域的外文翻译范例，以帮助大家更好地理解和掌握外文翻译的技巧与要点。
一、科技文献翻译原文：The development of artificial intelligence has brought about revolutionary changes in various fields, such as healthcare, finance, and transportation译文：人工智能的发展给医疗保健、金融和交通运输等各个领域带来了革命性的变化。
在这个范例中，翻译准确地传达了原文的意思。
“artificial intelligence”被准确地翻译为“人工智能”，“revolutionary changes”翻译为“革命性的变化”，“various fields”翻译为“各个领域”，用词准确、贴切，符合科技文献严谨、客观的语言风格。
二、商务合同翻译原文：This Agreement shall commence on the effective date and shall continue in force for a period of five years, unless earlier terminated in accordance with the provisions herein译文：本协议自生效日起生效，并将持续有效五年，除非根据本协议的规定提前终止。
商务合同的翻译需要格外注重准确性和专业性。
上述译文中，“commence”翻译为“生效”，“in force”翻译为“有效”，“terminated”翻译为“终止”，清晰准确地表达了合同条款的含义，避免了可能的歧义。
三、文学作品翻译原文：The sun was setting, painting the sky with hues of orange and pink, as if nature were a master artist at work译文：太阳正在西沉，把天空涂成了橙色和粉色，仿佛大自然是一位正在创作的艺术大师。
中英文对照翻译文章
中英⽂对照翻译⽂章 不少英⽂⽂章都是带有翻译的，为的就是⽅便读者在不理解⽂章的时候能够找到对照的意思。
下⾯就是店铺给⼤家整理的中英⽂对照翻译⽂章，希望⼤家喜欢。
中英⽂对照翻译⽂章篇1：A Sailor's Christmas Gift ⼀个⽔⼿的圣诞礼物 William J·Lederer 威廉·J·莱德勒 Last year at Christmas time my wife，three boys，and I were in France，on our way from Paristo Nice.For five wretched days ererything had gone wrong.Our hotels were“touristtraps”;our rented car broke down;we were all restless and irritable in the crowded car.OnChristmas Eve，when we checked into a dingy hotel in Nice，there was no Christmas spirit inour hearts. 去年，在圣诞节期间，我和我的妻⼦以及我们的三个孩⼦，从法国踏上由巴黎到尼斯的旅途。
由于接连五天的恶劣天⽓，旅途上⼀切很不顺⼼。
我们下榻的旅馆尽是些敲诈勒索旅客的“陷阱”;我们租⽤的那辆汽车⽼是发⽣故障，在拥挤不堪的车⼦上⼤家个个显得烦躁不安。
圣诞节前⼣，我们住进了尼斯的⼀家旅店，这家旅店⼜脏⼜暗，我们打⼼眼⾥感觉不到丝毫的节⽇⽓氛。
It was raining and cold when we went out to eat.We found a drab littlejoint shoddily decoratedfor the holiday.It smelled greasy.Only five tables in the restaurant were occupied.Therewere two German couples，two French families，and an American sailor，by himself.In thecorner a piano player listlessly played Christmas music. 我们外出就餐时，天正下着⼩⾬，天⽓寒冷。
毕业论文外文翻译范例
外文原文(一)Savigny and his Anglo-American Disciple s*M. H. HoeflichFriedrich Carl von Savigny, nobleman, law reformer, champion of the revived German professoriate, and founder of the Historical School of jurisprudence, not only helped to revolutionize the study of law and legal institutions in Germany and in other civil law countries, but also exercised a profound influence on many of the most creative jurists and legal scholars in England and the United States. Nevertheless, tracing the influence of an individual is always a difficult task. It is especially difficult as regards Savigny and the approach to law and legal sources propounded by the Historical School. This difficulty arises, in part, because Savigny was not alone in adopting this approach. Hugo, for instance, espoused quite similar ideas in Germany; George Long echoed many of these concepts in England during the 1850s, and, of course, Sir Henry Sumner Maine also espoused many of these same concepts central to historical jurisprudence in England in the 1860s and 1870s. Thus, when one looks at the doctrinal writings of British and American jurists and legal scholars in the period before 1875, it is often impossible to say with any certainty that a particular idea which sounds very much the sort of thing that might, indeed, have been derived from Savigny's works, was, in fact, so derived. It is possible, nevertheless, to trace much of the influence of Savigny and his legal writings in the United States and in Great Britain during this period with some certainty because so great was his fame and so great was the respect accorded to his published work that explicit references to him and to his work abound in the doctrinal writing of this period, as well as in actual law cases in the courts. Thus, Max Gutzwiller, in his classic study Der einfluss Savignys auf die Entwicklung des International privatrechts, was able to show how Savigny's ideas on conflict of laws influenced such English and American scholars as Story, Phillimore, Burge, and Dicey. Similarly, Andreas Schwarz, in his "Einflusse Deutscher Zivilistik im Auslande," briefly sketched Savigny's influence upon John Austin, Frederick Pollock, and James Bryce. In this article I wish to examine Savigny's influence over a broader spectrum and to draw a picture of his general fame and reputation both in Britain and in the United States as the leading Romanist, legal historian, and German legal academic of his day. The picture of this Anglo-American respect accorded to Savigny and the historical school of jurisprudence which emerges from these sources is fascinating. It sheds light not only upon Savigny’s trans-channel, trans-Atlantic fame, but also upon the extraordinarily*M.H.Hoeflich, Savigny and his Anglo-American Disciples, American Journal of Comparative Law, vol.37, No.1, 1989.cosmopolitan outlook of many of the leading American and English jurists of the time. Of course, when one sets out to trace the influence of a particular individual and his work, it is necessary to demonstrate, if possible, precisely how knowledge of the man and his work was transmitted. In the case of Savigny and his work on Roman law and ideas of historical jurisprudence, there were three principal modes of transmission. First, there was the direct influence he exercised through his contacts with American lawyers and scholars. Second, there was the influence he exercised through his books. Third, there was the influence he exerted indirectly through intermediate scholars and their works. Let us examine each mode separately.I.INFLUENCE OF THE TRANSLATED WORKSWhile American and British interest in German legal scholarship was high in the antebellum period, the number of American and English jurists who could read German fluently was relatively low. Even those who borrowed from the Germans, for instance, Joseph Story, most often had to depend upon translations. It is thus quite important that Savigny’s works were amongst the most frequently translated into English, both in the United States and in Great Britain. His most influential early work, the Vom Beruf unserer Zeitfur Rechtsgeschichte und Gestzgebung, was translated into English by Abraham Hayward and published in London in 1831. Two years earlier the first volume of his History of Roman Law in the Middle Ages was translated by Cathcart and published in Edinburgh. In 1830, as well, a French translation was published at Paris. Sir Erskine Perry's translation of Savigny's Treatise on Possession was published in London in 1848. This was followed by Archibald Brown's epitome of the treatise on possession in 1872 and Rattigan's translation of the second volume of the System as Jural Relations or the Law of Persons in 1884. Guthrie published a translation of the seventh volume of the System as Private International Law at Edinburgh in 1869. Indeed, two English translations were even published in the far flung corners of the British Raj. A translation of the first volume of the System was published by William Holloway at Madras in 1867 and the volume on possession was translated by Kelleher and published at Calcutta in 1888. Thus, the determined English-speaking scholar had ample access to Savigny's works throughout the nineteenth century.Equally important for the dissemination of Savigny's ideas were those books and articles published in English that explained and analyzed his works. A number of these must have played an important role in this process. One of the earliest of these is John Reddie's Historical Notices of the Roman law and of the Progress of its Study in Germany, published at Edinburgh in 1826. Reddie was a noted Scots jurist and held the Gottingen J.U.D. The book, significantly, is dedicated to Gustav Hugo. It is of that genre known as an external history of Roman law-not so much a history of substantive Roman legal doctrine but rather a historyof Roman legal institutions and of the study of Roman law from antiquity through the nineteenth century. It is very much a polemic for the study of Roman law and for the Historical School. It imparts to the reader the excitement of Savigny and his followers about the study of law historically and it is clear that no reader of the work could possibly be left unmoved. It is, in short, the first work of public relations in English on behalf of Savigny and his ideas.Having mentioned Reddie's promotion of Savigny and the Historical School, it is important to understand the level of excitement with which things Roman and especially Roman law were greeted during this period. Many of the finest American jurists were attracted-to use Peter Stein's term-to Roman and Civil law, but attracted in a way that, at times, seems to have been more enthusiastic than intellectual. Similarly, Roman and Civil law excited much interest in Great Britain, as illustrated by the distinctly Roman influence to be found in the work of John Austin. The attraction of Roman and Civil law can be illustrated and best understood, perhaps, in the context of the publicity and excitement in the English-speaking world surrounding the discovery of the only complete manuscript of the classical Roman jurist Gaius' Institutes in Italy in 1816 by the ancient historian and German consul at Rome, B.G. Niebuhr. Niebuhr, the greatest ancient historian of his time, turned to Savigny for help with the Gaius manuscript (indeed, it was Savigny who recognized the manuscript for what it was) and, almost immediately, the books and journals-not just law journals by any means-were filled with accounts of the discovery, its importance to legal historical studies, and, of course, what it said. For instance, the second volume of the American Jurist contains a long article on the civil law by the scholarly Boston lawyer and classicist, John Pickering. The first quarter of the article is a gushing account of the discovery and first publication of the Gaius manuscript and a paean to Niebuhr and Savigny for their role in this. Similarly, in an article published in the London Law Magazine in 1829 on the civil law, the author contemptuously refers to a certain professor who continued to tell his students that the text of Gaius' Institutes was lost for all time. What could better show his ignorance of all things legal and literary than to be unaware of Niebuhr's great discovery?Another example of this reaction to the discovery of the Gaius palimpsest is to be found in David Irving's Introduction to the Study of the Civil Law. This volume is also more a history of Roman legal scholarship and sources than a study of substantive Roman law. Its pages are filled with references to Savigny's Geschichte and its approach clearly reflects the influence of the Historical School. Indeed, Irving speaks of Savigny's work as "one of the most remarkable productions of the age." He must have been truly impressed with German scholarship and must also have been able to convince the Faculty of Advocates, forwhom he was librarian, of the worth of German scholarship, for in 1820 the Faculty sent him to Gottingen so that he might study their law libraries. Irving devotes several pages of his elementary textbook on Roman law to the praise of the "remarkable" discovery of the Gaius palimpsest. He traces the discovery of the text by Niebuhr and Savigny in language that would have befitted an adventure tale. He elaborates on the various labors required to produce a new edition of the text and was particularly impressed by the use of a then new chemical process to make the under text of the palimpsest visible. He speaks of the reception of the new text as being greeted with "ardor and exultation" strong words for those who spend their lives amidst the "musty tomes" of the Roman law.This excitement over the Verona Gaius is really rather strange. Much of the substance of the Gaius text was already known to legal historians and civil lawyers from its incorporation into Justinian's Institutes and so, from a substantive legal perspective, the find was not crucial. The Gaius did provide new information on Roman procedural rules and it did also provide additional information for those scholars attempting to reconstruct pre-Justinianic Roman law. Nevertheless, these contributions alone seem hardly able to justify the excitement the discovery caused. Instead, I think that the Verona Gaius discovery simply hit a chord in the literary and legal community much the same as did the discovery of the Rosetta Stone or of Schliemann’s Troy. Here was a monument of a great civilization brought newly to light and able to be read for the first time in millenia. And just as the Rosetta Stone helped to establish the modern discipline of Egyptology and Schliemann's discoveries assured the development of classical archaeology as a modern academic discipline, the discovery of the Verona Gaius added to the attraction Roman law held for scholars and for lawyers, even amongst those who were not Romanists by profession. Ancillary to this, the discovery and publication of the Gaius manuscript also added to the fame of the two principals involved in the discovery, Niebuhr and Savigny. What this meant in the English-speaking world is that even those who could not or did not wish to read Savigny's technical works knew of him as one of the discoverers of the Gaius text. This fame itself may well have helped in spreading Savigny's legal and philosophical ideas, for, I would suggest, the Gaius "connection" may well have disposed people to read other of Savigny's writings, unconnected to the Gaius, because they were already familiar with his name.Another example of an English-speaking promoter of Savigny is Luther Stearns Cushing, a noted Boston lawyer who lectured on Roman law at the Harvard Law School in 1848-49 and again in 1851- 1852.Cushing published his lectures at Boston in 1854 under the title An Introduction to the Study of Roman Law. He devoted a full chapter to a description of the historical school and to the controversy betweenSavigny and Thibaut over codification. While Cushing attempted to portray fairly the arguments of both sides, he left no doubt as to his preference for Savigny's approach:The labors of the historical school have established an entirely new and distinct era in the study of the Roman jurisprudence; and though these writers cannot be said to have thrown their predecessors into the shade, it seems to be generally admitted, that almost every branch of the Roman law has received some important modification at their hands, and that a knowledge of their writings, to some extent, at least, is essentially necessary to its acquisition.译文(一)萨维尼和他的英美信徒们*M·H·豪弗里奇弗雷德里奇·卡尔·冯·萨维尼出身贵族，是一位出色的法律改革家，也是一位倡导重建德国教授协会的拥护者，还是历史法学派的创建人之一。
经典外文翻译两篇,中英对照
外文原文 1Building Materials Selection and SpecificationFae'q A. A. RadwanFaculty of Engineering, Near East University, KKTC, Lefkosa, Mersin 10, TurkeyAbstract: The limitations in the selection of the building materials and to the sustainability of any building construction materials that can be used are presented. The practices and techniques that can be used in reducing and minimizing the environmental impacts of building are discussed. Recommendations of using secondary and recycled materials in the construction of buildings are given. Framework for methods of assessment of the sustainability in building construction for environmental performance is presented.Key Words: Limitations, sustainability, environmental impacts, framework, climate.1. IntroductionThere is an apparently unbounded range of possibilities for the selection of building materials for the construction of structures of almost any shape or stature. Its quality will affect the structure function and long life, and requirements may differ with climate, soil, site size, and with the experience and knowledge of the designer. The factors that have the most outstanding solutions are impermeability, control of heat, air, and water flow, and the stability of the structure [1-3].Raw materials extraction, manufacturing processes, and the transportation of the materials to the project site have a multitude of impacts on the environment. These include the disruption of habitats and ecological systems, use of water, and, through energy use, the emissions of air pollutants and climate change gases. Building materials also have major impacts on the building occupants manufacture, construction of buildings and the use of building materials make a significant environmental impact internally, locally and globally. But it is not easy to deliver information to make adequate inclusion decisions considering the whole life cycle of a building. Decisions on sustainable building integrate a number of strategies during the design, construction and operation of building projects. Selection of sustainable building materials represents an important strategy in the design of a building.2.SustainabilityIn recent years, the concept of sustainability has been the subject of much disputation by academics and professionals alike. In 1987, the World Conference on Environment and Development defined sustainable development as development that meets the needs of the present without compromising the ability of future generations to meet their own needs (WCED, 1987).Sustainability must address ecological impacts, regardless of conflicting interpretations of the WCED definition.A good sustainable product must give as much satisfaction as possible for the user. If not, it will be unsuccessful on the market and an economic failure.It is also important to inform people as to what basis a certain product is considered to be sustainable or not and why they should buy it [4- 5].When developing a new product, it is illustrative to move between the three corners Ecology, Equity and Economy in order to obtain a suitable balance so that each category can be fulfilled in the best way.·Ecology (environmental protection).·Equity (social equity).·Economy (economic growth).2.1 Materials Selection and SustainabilityAmong the notable technological developments of the 20th century has been the development of tens of thousands of new materials for use in construction and engineering. The construction industry has also grown to the point where it is a very large consumer of energy and materials. Concern for the environment and the impact of human activity on the Earth's ecological systems has now become clear sighted.We are faced with the problems of material selection and the environmental consequences of their use. Environmentalists have proposed various methods for assessing the impact of materials and energy use, these include ecological foot printing, ecological rucksacks, embodied energy and carbon dioxide values, and so on. Engineers have put forward rational selection methods for the choice of materials. These techniques will be reviewed and explored in an attempt to provide an environmentally-aware, materials selection method- logy for use in construction.Strictly, the term sustainable means that something is capable of being sustained not for an hour, or a day, or a week, month or year, but indefinitely.The implication is that if some process which uses materials and energy is described as sustainable, then the materials and energy which are consumed arecapable of being replaced by natural or other processes as fast as they are consumed. In many cases materials and energy appear to be consumed at a faster rate than they are being replaced. However, to make a judgment, we would need to know what the respective supply and consumption rates are in other words we need some quantitative or numerical index to help us [2].2.2 Environmental CriteriaSince construction uses such large quantities of materials, it has a major impact on the environment. In order to assess and evaluate such impact, a number of criteria or indices have been devised by economists, engineers and environmentalists, and the more important of these are the following [2].2.2.1 Embodied EnergyThis is quite simply the amount of energy consumed in manufacturing a unit quantity of a material, and it is usually expressed in kJ/kg. Its value is determined by the efficiency of the manufacturing plant. Values range from 275 GJ/tonne for aluminum (a high value) to 0.1 GJ/tonne for gravel aggregates (a low value) [2].2.2.2 Embodied Carbon DioxideEmbodied C02 is similar to embodied energy. It is the weight of C02 emitted during manufacture of unit weight of the material, and is usually expressed as kg of C02 per ton.Again, the value will depend upon the efficiency of the manufacturing plant [2].2.2.3 Ecological RucksackThe ecological rucksack concept was devised as a way of assessing material efficiency by F. Schmidt一Bleek [6]. He recognized that many tonnes of raw material could be extracted and processed to make just one kilogram of material. For example, the environmental rucksack for the precious metal platinum is 250,000:1.2.3 Rational Selection MethodThere are various approaches to the problem of selecting materials from the huge numbers now available. Designers can have recourse to materials property charts and data books. Alternatively, they can talk to their colleagues, hoping that by widening the knowledge circle, they will not omit a significant group of materials. Another strategy is simply to specify the same or a similar material to those used in previous, similar designs. All these are valid approaches, but they may result in the specification of a less than ideal material and overall, a less than optimal solution to the problem [3-5].The basis of the rational selection methods devised to date is a recognition that the performance of a component, artifact or structure is limited by the properties of the materials from which it is made. It will be rare for the performance of the item to depend solely on one material property; in nearly all cases, it is a combination of properties, which is important. To give an example, in lightweight design, strength to weight ratio of, and stiffness to weight ratio E/pwill be important. Ref. [3] has put forward the idea of plotting material properties against each other to produce material property maps. On these maps, each class of material occupies a field in material property space, and sub-fields map the space occupied by individual materials.These materials property charts are very information-rich they carry a large amount of information in a compact but accessible form. Interestingly, they reveal correlations between material properties, which can help in checking and estimating data, and they can also be used in performance optimization, in a manner such as that set out as follow.If we consider the complete range of materials, it immediately becomes apparent that for each property of an engineering material there is a characteristic range of values, and this range can be very large. For example, consider stiffness (Young's Modulus E). Materials range from jelly (very low stiffness) up to diamond (very high stiffness). The properties can span five decades (orders of magnitude),A number of conclusions can be drawn, including:(1) A rational selection method such the one put forward by Ashby is capable of incorporating environmental parameters such as embodied energy and C02 or the environmental rucksack concepts, thereby making possible rational selections based on environmental considerations.(2) This method is not as simple to use as the environmental preference method or the environmental profiles method. However, this rational method could be used to generate data for the environmental profiles and preference methods.(3) The construction industry needs to take steps to better integrate itself into the materials cycle. The quantity of demolition waste needs to be reduced, and more of it should be recycled. To this end, the building designers need to keep full records of materials of construction, and buildings need to be designed for easy dismantling at the end of their useful lives.2. 4 Ashby's Materials Selection MethodologyMaterials selection charts一Property interaction (not always causal)一First order optimization●Performance indices●Multiple constrains●Multiple design goals●Shape and material interaction一“Enhanced" performance indicesProcess selection [3, 4].3. Foundations and Construction ComponentIn any consideration of which building materials and alternatives can feasibly be integrated into the foundations of a large-scale development there are several limitations that must be considered.In terms of the actual materials that may be used, there are three main limitations. First, because of the large scale and heavy loads that the foundations must support, strength is imperative. Any materials must be consistently strong and able to effectively distribute the weight of the structure. The second major limitation is climate. In areas with sub-zero winter conditions, frost heave is a major consideration. For this reason, foundations must be deep enough to support the structure despite any changes in near-surface volume; shallow foundations will be insufficient unless certain innovative steps are taken. The limitation of climate also influences any decision on insulating foundations. Finally, there is the consideration of cost. This consideration is reliant on material availability, cost per unit, and building techniques and associated labor. For these reasons, the only materials that can feasibly be used are concrete and steel. Therefore, the alternatives for minimizing impact lie more in the methods of construction and any realistic structural changes that can be made.The three main foundation components of concrete, steel, and insulation will be examined as the only reasonable materials for the construction of a building with limitations such as the foundations [1].3.1 ConcreteIt is the fundamental component of the foundation construction, receiving the building loads through walls or posts and distributes them down and outwards through the footings. Concrete and cement have ecological advantages which include durability, long life, heat storage capability, and (in general) chemical inertness [8].The life cycle concerns of concrete are as follows. First, there is land and habitat loss from mining activities. Furthermore, the quality of both air and water quality suffer from the acquisition, transportation, and manufacture. Carbon dioxide emissions are also a negative environmental impact accrued through the production and use of concrete. Similarly, dust and particulate are emitted at most stages of the concrete life-cycle. $oth carbon dioxide and particulate matter have negative impacts on air quality [1]. Water pollution is also another concern associated with the production of concrete at the production phase. Fly ash is by-product of the energy production from coal-fired plants and increasing its proportion in cement is environmentally beneficial in two ways. First, it helps in reducing the amount of solid waste which requires disposal. As well, fly ash in the cement mixture reduced the overall energy use by changing the consistency of the concrete. Fly ash, increases concrete strength, improves sulfate foundation, decreases permeability, reduced the water ratio required, and improves the pump ability and workability of the concrete [9]. Now in the United States, the Environmental Protection Agency requires that all buildings that receive federa funding contain fly ash and most concrete producer: have access to this industrial waste [9].There are alternative methods of both making concrete and building foundations with this concrete that have environmental benefits, no matter the structure scale or climate. These include Autoclaved Aerated Concrete, the increased integration of fly ash into the cement mixture, and the use of pre-cast foundation systems to reduce resource use. Through consideration and possible integration of these alternatives, impacts could potentially be reduced.3.2 SteelAs wood resources are becoming limited, steel is increasingly popular with builders. In the case of a large-scale building, steel reinforcement is basically a necessity for overall strength and weight distribution.The initial life cycle impacts of steel use are similar to those of concrete. These include land and habitat loss from mining activities, and air and water quality degradation from materials acquisition and manufacture [1]. However, the largest proportion of steel used nowadays contains a percentage of recycled materials. In terms of improving environmental conditions by reducing impacts, this is the only real recommendation for the use of steel in building foundations; to purchase recycled steel products. Not only would this reduce industrial and commercial solid waste,such a decision would also reward the manufacturers of such products.3. 3 InsulationNew and innovative pre-cast building foundations are becoming increasingly available and feasible for implementation. These new systems can reduce the overall raw material use, as well as conserve energy through the creation of an efficient building envelope. A further used of this rigid insulation as a skirt around the building foundations helps to eliminate any potential frost problems, improve drainage, and help further reduce heat loss. A polyethylene air and water vapor barrier is applied above the insulating layer, as is a three to four inch layer of sand. These shallow foundation systems have excellent insulating properties, decreased use of raw materials for concrete, and comparatively low demands for labor. However, the use of rigid insulation is increased. Also, in soils where frost and drainage is a consideration additional piles in the centre of the foundation may be required to prevent movement. This increases the relative land disturbance, although it remains still much less than that of deep foundation systems. Shallow foundations are structurally sound and are becoming increasingly common in colder climates. There are strength considerations associated with these new techniques which must be addressed by someone with the technical ability to do so, before they can be feasibly recommended for the building of the new residence.As discussed above, there are limitations to the sustainability of any foundation construction materials used. In other words, there are environmental impacts associated with all types of foundations. For these reasons, a primary recommendation is the use of secondary materials (fly ash and recycled steel) in the construction of foundations.4. FrameworkThe material components of the building envelope, that is, the foundation, wall construction, insulation and roof, have been analyzed within a framework of primarily qualitative criteria that aim to evaluate the sustainability of alternate materials relative to the materials cited in the current foundation design. This analytical process has enabled the identification of several construction materials that can be feasibly integrated into current design and construction standards of the building envelope.The tools and strategies described below are useful in analyzing the relative benefits of different materials[9-14].Life-Cycle Assessment (LCA). LCA is a comprehensive analysis that takes intoconsideration all aspects of a material over its entire lifetime: raw materials extraction; manufacturing and processing; transport; use; and post-use recycling, reuse, or disposal. This approach enables a true "apples to apples" comparison between materials.The BEES system (Building for Environmental and Economic Sustainability) developed by the National Institute of Standards and Technology is the most widely used methodology. BEES provides materials with a score that can be compared to other similar products. At this time, however, a fairly limited number of materials have completed the BEES analysis.Life-Cycle Costing. Life-Cycle Costing is an analysis of the short- and long-term costs associated with a material, from purchase to ultimate recycling or disposal. This includes frequency of replacement, maintenance costs, and costs that are avoided through use of the material (or system). LCC is useful in looking beyond a comparison based solely on first costs. Similar to LCA, this type of analysis is not available for all materials, but a back-of-the-envelope calculation is usually fairly easy to work up.Certification. Many conventional building products are approved or certified by independent third party or government groups. The Forest Stewardship Council certifies the certifiers (Smart Wood and SCS) that assess whether forestry companies are using sustainable management practices to harvest wood. The Carpet and Rug Institute provides a Green Label for carpets that meet certain low-VOC criteria. Green Guard certifies products that meet strict indoor air quality criteria. The Department of Energy's Energy Star label identifies equipment and appliances that meet or exceed standards for energy efficiency. Scientific Certification Systems and Green Seal certify recycled-content claims and other green product claims made by manufacturers.5. ConclusionOver-consumption, resource utilization, pollution and over-population are examples of the perhaps most basic problems for the environment in the future. A more sustainable future can be achieved by producing more sustainable products causing less environmental impact. Materials and design are and will always be very important areas when developing more sustainable products.The Life Cycle Assessment concept might be the most effective way of determining the environmental impacts for all product stages from extract of material to the product disposal stage. A price must be set for restoration on everyenvironmental impact. Information can be received from official authorities pertaining to the environment in different countries. Renewable and easy recyclable materials are preferably used together with a design for easy recycling and repair of the products. Minimization of the energy connected to the product is also important. Full sustainability can never be achieved for products according to thermodynamic laws. However, the attempt to achieve more sustainability is a requisite if we want to preserve the earth for the coming generations. Education, research and spreading of information will be very important for the future in order to receive more sustainable products especially because the market demand is important in order to develop successful sustainable products.References[1] M. Davison, J. Persmann, J. Reid, J. Stange and T. Weins, Green BuildingMaterials Residence, A WATgreen/ERS 285 study.[2] J. L. Sturges, Construction Materials Selection and Sustainability, School of theBuilt Environment, Leeds Metropolitan University, UK.[3] M. F. Ashby, Materials Selection in Mechanical Design, Pergamon, Oxford, 1992.[4] M. F. Ashby and K. Johnson, Materials and Design: The Art And Science ofMaterials Selection in Product Design, Oxford: Butterworth-Heinemann, 2002 [5] L. Y. Ljungberg, Materials selection and design for development of sustainableproducts, Materials and Design 28(2007)466-479.[6] F. Berkhout and D. Smith, Products and the environment: an integrated approachto policy, Eur. Environ 9 (1999)174-185.[7] F. Schmidt-Bleek, Carnoules Declaration of the FactorTen Club, WuppertalInstitute, Germany, 1994.[8] A．Wilson，Building green on a budget,Environmental Building News8(5)(1999)．[9] G．E．Dieter，Engineering Design，McGraw-Hill，New York，l991．[10] Sandy Patience (Ed．)，The Role of Evidence in The Selection of BuildingProducts and Materials，Constructing Excellence in The Built Environment．[11] M．D．Bovea and R．Vidal，Increasing product value by integrating environmentalimpacts costs and customer valuation，J Resour Conserv Recycling 41(2004) 133-145．[12] N．S．Ermolaeva,M．B．G．Castro and P．V．Kandachar, Materials selectionfor an automotive structure by integrating structural optimization with environmental impact assessment，Materials and Design 25 (2004) 689．698．[13] M．Goedkoop and R．Spiensma，The Eco-Indicator 99：A Dam age OrientedMethod for Life Cycle Impact Assessment，Amersfooft：PRe consultant B．V．，2000．中文翻译 1建材选择和规格Fae'q A. A. RadwanFaculty of Engineering, Near East University, KKTC, Lefkosa, Mersin 10, Turkey摘要：建材选择的限制和可利用的任何建筑物工程材料的持久性显现出来。
英语四级翻译10篇
英语四级翻译10篇英语四级翻译10篇1.剪纸(paper cutting)是中国最为流行的传统民间艺术形式之一。
中国剪纸有一千五百多年的历史,在明朝和清朝时期(the Ming and Qing Dynasties)特别流行。
人们常用剪纸美化居家环境。
特别是在春节和婚庆期间,剪纸被用来装饰门窗和房间,以增加喜庆的气氛。
剪纸最常用的颜色是红色,象征健康和兴旺。
中国剪纸在世界各地很受欢迎,经常被用作馈赠外国友人的礼物。
[参考译文]Paper cutting is one of China’s most popular traditional folk arts. Chinese paper cutting has a history of more than 1,500 years. It was widespread particularly during the Ming and Qing Dynasties. People often beautify their homes with paper cuttings. During the Spring Festival and wedding celebrations, in particular, paper cuttings are used to decorate doors, windows and rooms in order to enhance the joyous atmosphere. The color most frequently used in paper cutting is red, which symbolizes health and prosperity. Chinese paper cutting is very popular around the world and it is often given asa present to foreign friends.2.公元220年开始的300年里，中国分成了三个小王国。
外文译文例文
第二次国际会议的新趋势，在工程和技术，icetet-09使用嵌入式系统的智能交通灯控制器的设计①席美国查万（沃克）1，R.S.德什潘德博士3,J. G.拉纳21.学生，M . E .（电子）2.尼赫鲁工程学院，奥兰加巴德，马哈拉施特拉邦，印度。
3.学院院长、教授，电子系，有raisoni教育基础的工程技术学院管理，查斯，阿迈德那格尔，印度。
摘要：目前的交通灯控制器（TLC）基于微控制器和微处理器。
这些TLC有限制，因为它使用预先定义的硬件，这是运作按程序，不具备实时的基础上修改的灵活性。
由于固定时间间隔的绿色，橙色和红色信号的等待时间和汽车使用更多的燃料。
交通灯控制更有效率，我们利用新技术的出现称为“智能交通灯控制器”。
这使得随着嵌入式技术的传感器网络的使用。
将红，绿灯的时间，在每个过路明智决定的基础上对所有相邻的总流量道路。
因此，优化交通灯的开关增加道路通行能力和交通流量，可以防止交通塞车。
还为用户提供GSM手机界面那些希望获得最新的交通位置拥挤的道路。
这是这是这个项目的独特功能非常有用的汽车司机的情况下采取的备用路由挤塞情况。
各种性能的评价标准平均轮候时间，车辆行驶的平均距离，开关频率在一个路口绿灯，高效紧急模式运作和令人满意的短信操作使用GSM手机。
智能交通的性能灯光控制器是比较固定的模式红绿灯控制器。
它指出，拟议的智能交通光控制器比传统的更有效控制器减少了等待时间，更多的行驶距离平均车辆和在紧急情况下的高效运作模式和GSM接口。
此外，系统设计结构简单，响应时间快，用户友好和为进一步扩大范围。
关键词：智能交通灯控制器、嵌入式系统、绩效评价、微机系统一.导言快速的运输系统和快速公交系统是任何一个国家的经济发展的神经。
所有发达国家都有高效的交通控制系统公路、铁路和航空的交通系统。
运输的货物、工业产品、人力和机械是影响任何国家的工业发展的关键因素。
管理不善和交通挤塞的情况会导致长时间等待，燃料和钱的损失。
外文翻译范文
本科毕业论文外文文献及译文文献、资料题目：Measurements and Predictions of Steady-State and Transient Stress Distributionsin a Diesel Engine Cylinder Head文献、资料来源：SAE文献、资料发表日期：1999.4院（部）：机电工程学院专业：班级：姓名：学号：指导教师：完成日期：外文文献：Measurements and Predictions of Steady-State and Transient Stress Distributions in a Diesel Engine Cylinder Head ABSTRACTA combined experimental and analytical approach was followed in this work to study stress distributions and causes of failure in diesel cylinder heads under steady-state and transient operation. Experimental studies were conducted first to measure temperatures, heat fluxes and stresses under a series of steady-state operating conditions. Furthermore, by placing high temperature strain gages within the thermal penetration depth of the cylinder head, the effect of thermal shock loading under rapid transients was studied. A comparison of our steady-state and transient measurements suggests that the steady-state temperature gradients and the level of temperatures are the primary causes of thermal fatigue in cast-iron cylinder heads. Subsequently, a finite element analysis was conducted to predict the detailed steady-state temperature and stress distributions within the cylinder head. A comparison of the predicted steady-state temperatures and stresses compared well with our measurements. Furthermore, the predicted location of the crack initiation point correlated well with experimental observations. This suggests that a validated steady-state FEM stress analysis can play a very effective role in the rapid prototyping of cast-iron cylinder heads.INTRODUCTIONHeavy-duty diesel engine cylinder heads experience severe thermal and mechanical loading, under both steady-state and transient engine operation. Consequently, cylinder head design is very sophisticated as it needs to house complex cooling passages for ensuring compliance with thermal stresses, while providing sufficient mechanical strength to withstand combustion pressures, and yet accommodating intake and exhaust valves and ports, and the fuel injector. As a result of design, weight and manufacturing compromises, cylinder heads often fail in operation due to cracks that are initiated due to thermal fatigue in regions where cooling is limited, such as in the narrow bridge between valves, or around the exhaust valve seat.A number of studies have so far been conducted to develop analytical methodologies1suitable for rapid design and virtual prototyping of cylinder heads. The finite element method has been the foundation of many of the analyses that predict the thermal and stress fields within the cylinder head. However, the accuracy of such analyses critically depends on our understanding of the problem, and the accuracy of the boundary conditions used in the formulation. Thermal stresses are induced by any of the following causes：Temperature gradients under steady-state operation, including the effects of cyclic temperature changes in the combustion chamber wallAn increase in the mean temperature of a component, which affects the expansion and distortion characteristics, thus inducing stressesThermal shock loading resulting from a sudden change in speed or load during transients, which change the rate of heat flux from the gas to the cylinder head.Due to the inherent difficulties in measuring stress fields near the critical regions on the firedeck surface, especially under transient conditions, limited sets of measurements that can shed light on the problem have been reported .A numerical study of thermal shock calculations by Keribar and Morel has shown that thermal waves propagate into components during engine transients, with the steepness of the front depending on material thermal properties. While for a ceramic component severe shock loads can cause surface compressive stresses to overshoot final steady-state values, the effect was not pronounced in higher conductivity materials. In order to validate this analytical finding, and attribute appropriately causes of failure in cast-iron cylinder heads, a combined experimental and analytical approach is followed here to study stress distributions under steady-state and transient operation.Experimental studies are conducted first to measure temperatures, heat fluxes and stresses under a series of steady-state and transient operating conditions. Both biaxial and uni-axial high temperature strain gages have been inserted within the thermal penetration depth of a diesel engine cylinder head. The strain gage insertion beneath the surface of the firedeck ensures the durability and reliability of the sensor. At the same time, the placement within the thermal penetration depth allows for studying the effect of thermal shock loading under rapid transients, and for contrasting those measurements with corresponding steady-state magnitudes. Subsequently, a finite element analysis is2conducted to predict the steady-state temperature and stress distributions within the cylinder head. Predictions are compared with measurements, and the potential of the method to predict high stress regions that could lead to crack initiation is explored. EXPERIMENTAL MEASUREMENTSEXPERIMENTAL SETUP – Temperature, heat flux and stress measurements were acquired on a six-cylinder, naturally-aspirated, direct-injection, Hyundai diesel engine, primarily used in bus applications. The primary specifications of the engine are reported in Table 1.TEMPERATURE AND HEAT FLUX SENSORS – A total of 8 steady-state temperature and heat flux probes were installed around the intake and exhaust valve seats of cylinders #2 and #6. The probe tips were mounted at a depth of 1.0 mm beneath the firedeck surface, at the locations shown in Figs. 1 and 2. A schematic diagram showing the construction of the temperature and heat flux probe is shown in Fig. 3. The probe was made of Ktype thermocouples. A near-surface (1.0 mm beneath the firedeck) and an in-depth junction (4.0 mm beneath the surface) make it possible to calculate heat flux. To enhance the sensitivity of the junctions, a thin (1mm thickness), circular copper plate was welded at the tip of the sensor. Temperature and heat flux data were acquired every 1 second, under full load, over a speed range from 1000 rpm to 2500 rpm, every 500 rpm.Table 1. Specification of the test engineDisplacement Volume 7545 ccBore X StrokeCompression Ratio 17.5Ignition Order 1-5-3-6-2-4Maximum Torque 475 N·m @1500 rpmMaximum Power 123 kW @ 2200 rpm3Figure 1. Temperature and heat flux measuring points on the firedeck HIGH TEMPERATURE ST RAIN GAGES –For measuring stress within engine cylinder heads, especially near the gas-side surface, strain gages with high temperature durability are needed. A special procedure has been developed in this work for constructing a strain gage sensor plug (see Fig. 4) that is suitable for such measurements. The details of the sensor selection, attachment in the instrumentation plug, and verification of its operation are described next.Figure 2. Location of sensor on the firedeckFigure 3. Schematic diagram of temperature and heat flux sensorFigure 4. Schematic diagram illustrating strain gage sensor and critical dimensions Two types of high temperature strain gages (120Ωand 350Ω) were used. The45specifications of the sensors made by Micromeasurement Co. are described in Table 2. According to the manufacturer, the response time of the strain gages was 300 kHz (3.33 μs). In case of the 120Ωresistance bond after attachment to the inside surface of a cup-shaped plug. Then, the strain gage was heated in a microwave oven for 3 hours. After cooling to ambient temperature, the strain gage was recoated and re-heated at 150°C for 3 more hours. In case of the 350Ωstrain gage, heating was applied for a grand total of 4 hours at a temperature of 175°C.Table 2. Specifications of high temperature strain gages Gage Type WA-06-062TT-120 WA-06- 60WT-350Resistance in Ω 120.0 ± 0.4 % 350.0 ±0.4 %Lot NumberD-A38AD73 K44FD121 Gage FactorAt 75°F2.01 ± 0.5 % 2.07 ± 1.0 %Range Cont. Use-75 to 205°C-269 to 290°C Short Use-195 to 260°C 370°CFigure 5 shows a picture of the finished high temperature, strain gage plug assembly. Following construction of the instrumentation plug, its sensing behavior was explored. The plug temperature was varied by exposing it to a torch, and recorded via an attached thermocouple. Corresponding strain readings were also recorded. The experimentally measured strain versus temperature characteristic was compared to the one published by the manufacturer, and used as the basis for validating the sensor plug behavior.Figure 5. A photograph of high temperature strain gageThe highest component temperatures, and hence thermally- induced stresses are experienced at the combustion chamber surface. While it is desirable to measure stresses on the surface, sensors mounted flush with the surface have a very short life. In order to ensure the durability and reliability of the strain gage sensor plug, it was inserted 1.5 mm beneath the surface. This location was still within the penetration depth of thermal transients originating at the gas-side surface. Thus, it allowed studying the effect of thermal shock loading under rapid transients. A total of 4 strain gage sensor plugs were inserted near the intake and exhaust valve seats of cylinder #2 and #4 (see Fig. 6 ).Figure 6. Schematic diagram of strain gage positionThe stain gages inserted in cylinder #4 were of the biaxial type, measuring strain in the x and y directions, as defined in Fig. 7. The strain gages inserted in cylinder #2 were of the uni-axial type, measuring strain in a 45°axis. Since strain gage signals can be highly affected by even minute lead wire movement, care was exercised to attach them firmly to the engine head. Steady-state stresses were measured as speed was varied from 1000 rpm to 2000 rpm, in increments of 250 rpm, under full load. Transient stress measurements were also acquired every 0.01 seconds, while load was cycled between 0 and 100% for several engine speeds.Figure 7. Stress measurement directionsTEMPERATURE AND HEAT FLUX MEASUREMENTS – Figures 8 and 9 show6the steady-state temperatures measured at the four locations within the firedeck of cylinders #2 and #6, respectively. In all cases, the measured temperatures increase linearly with respect to engine speed. Increasing speed allows less time for heat transfer to the coolant between combustion events. The highest temperature values are recorded at location B, followed by those at A, C, and D. It should be noted that location B is between the injector nozzle hole and the exhaust valve. Since there is no coolant passage near that region, this explains why location B reaches the highest temperature of the four locations investigated. On the other hand, location D experiences the lowest temperature as it is exposed to significant forced cooling from the adjacent coolant passage and from the induced fresh air.Figure 8. Steady-state wall temperatures in cylinder #2 over a range of speedsFigure 9. Steady-state wall temperatures in cylinder #6 over a range of speeds Figures 10 and 11 show the corresponding steady-state heat fluxes computed at the same locations within cylinders #2 and #6, respectively. Again, heat flux increases linearly with engine speed. The heat flux magnitudes are higher for positions B and C,7located around the exhaust valve seat, compared to those at A and D, located around the intake valve seat. Note that as speed is increasing, different locations experience different rates of increase of heat flux, a fact that is attributed to differences in turbulent gas motion and coolant flow patterns. When the heat flux rates in cylinders #2 and #6 are compared (see Figs. 10 and 11), it can be noticed that the former experiences higher heat flux rates than the latter. This is attributed to the fact that the coolant flows first around cylinder #2; by the time it reaches cylinder #6, the coolant has picked up some heat and its temperature gradually rises, thus reducing the potential for heat transfer from cylinder #6. As a result of the higher heat fluxes, the firedeck temperatures around cylinder #2 are lower (by about 10 °C) than those around cylinder #6 that is located on the coolant outlet side.STRESS MEASUREMENTS –In order to be able to isolate the effect of pre-loading on the total stress measurements recorded in a fired engine by the various strain gages, stress measurements were taken during the engine assembly process. Measurements were taken at the four strain gages following the tightening of each head bolt. The initial stress variation is shown in Fig. 12. While the tightening of different bolts produced different amounts of tension and compression at the measurement location, no consistent pattern was revealed by the measurements. However, it is important to notice that pre-loading produced a negligible stress (within ±5MPa) at the measurement locations, irrespective of directions.Figure 10. Steady-state heat fluxes in cylinder #2 over a range of speeds8Figure 11. Steady-state heat fluxes in cylinder #6 over a range of speedsFigure 12. Effect of bolt tightening on pre-loading stressFigure 13 shows the steady-state stresses recorded by the bi-axial strain gages at intake and exhaust valve locations of cylinder #4, as well as the stresses recorded by the uni-axial strain gages at intake and exhaust valve locations of cylinder #2. The measurements were taken over a range of engine speeds and at full load, i.e. conditions that would produce the maximum stress at each speed. It must be noted that as engine speed is increased towards the maximum torque speed (1500 rpm), the measured stresses increase (or decrease) at a faster rate. Beyond the maximum torque speed, the stress variation is slight. Both tensile and compressive stresses appear simultaneously at the different locations, as shown in Fig. 13, thus indicating the complex character of the stress field.9Figure 13. Steady-state stress variation with respect to engine speed at full load The measured stress near the exhaust valve seat has negative values (x, y directions), indicating a compression effect. This could have been produced from a tendency of high temperature regions (such non-adequately cooled regions around the injector and the valve bridge) to expand, while subjected to mechanical constraints. As a result, the rest of the firedeck expands more in relative terms, as suggested by the tensile stresses experienced at the other measurement locations. It must also be noted that, at the various speeds, the absolute magnitude of the stresses near the exhaust valve are two to three times larger than those at the intake valve, for either cylinder #2 or #4. This correlates well with the two to three times higher heat flux measured on the exhaust valve seat compared to the corresponding heat flux on the intake valve seat (refer to results for locations B and A in Figs. 10 and 11).Figure 14. Transient stress variation in x and y directions at exhaust valve of cylinder #4Figure 15. Transient stress variation in x and y directions at intake valve of cylinder #4A transient test schedule has also been developed in order to assess the effect of thermal shock loading on the stresses measured at the same locations where steady-state measurements were reported. The schedule followed engine operation from cold start to firing under a series of speeds and loads. Figures 14 to 16 show the transient stresses recorded by the bi-axial and uni-axial strain gages at the instrumented locations near the exhaust and intake valves of cylinders #4 and #2. All figures indicate the same general characteristics. The period from A toB indicates the equilibrium state with coolant at room temperature and no thermally induced stresses. Upon turning on the engine (state B), a step change in stress level was observed at all measurement locations, except for the 45°direction around the intake valve seat of cylinder # 2 (see fig. 16). From B to C, temperatures and thermal stresses were stabilized while the engine was idling at a speed of 700 rpm. The stresses continued to increase (or decrease) smoothly, as speed was gradually increased from 700 rpm to 1000 rpm (C to D).Figure 16. Transient stress variation in 45° directions at exhaust and intake valves of cylinder #2Following engine warm-up (from state D on), a cyclic test pattern was imposed. Speed was increased from 1000 rpm to 2000 rpm in increments of 250 rpm, while the load was cycled between full load and no load at each test speed. The measured stresses followed a cyclic pattern as a result of the imposed large swings in gas temperatures and gas-side surface temperatures. The thermal shock loading experienced by the cylinder head during this severe transient is evident. It should be noted, however, that the absolute magnitudes of the stresses recorded at any instant during the transient exceed only marginally the levels that would correspond to steady-state operation under each of those conditions. This is attributed to the fact that thermal shock waves penetrate fast into the cast-iron cylinder head. Following the cyclic operation, the engine was turned-off (state F), and an abrupt change in stress levels was recorded. However, some residual stresses remained after shut-off, which required more than 7 hours to be relaxed. COMPUTATIONAL PREDICTIONSA three-dimensional numerical analysis based on the finite element method (FEM) can be used to predict the detailed steady-state temperature and stress distributions within the cylinder head. A synopsis of the FEM model, its validation against our measurements, and predictions using the model are reported below.FEM ANALYSIS – A three-dimensional finite element model of the cylinder head and block was composed, as shown in Fig. 17. Most of the grid elements are isoparametric solid brick with the rest of them being prism elements. A gasket model, represented as one row of elements has been inserted between the head and block models.A total of 12,156 nodes points and 7,803 elements were employed to described the FEM model. The cylinder head and block were made of cast-iron, while the gasket was assumed to be an indium composite material. Material properties are summarized in Tables 3 and 4. Steady-state, heat transfer and stress analyses were conducted using the commercial codes NISA II (solver) and DISPLAY III (pre and post-processor). The heat transfer analysis was conducted first. Subsequently, the heat transfer results were used to perform the stress analysis.Figure 17. 3-D FEM model of head and blockTable 3. Properties of cast-iron Table 4. Properties of indium composite materialThermal conductivity, k [W/m·K] 50.2 Thermal conductivity, k[W/m·K]0.17Young’s Modulus, E [GPa] 120.0 Young’s Modulus, E[GPa]19.15 0.29 0.4Thermal Expansion 12.0 x10-6Thermal Expansion 2.7 x 10-7For the heat transfer analysis, the boundary conditions shown in Table 5 were specified. The cyclic-mean values of the in-cylinder gas-to-wall heat transfer coefficient and bulk gas temperature were obtained from the comprehensive thermodynamic cycle simulation developed by Assanis and Heywood. The boundary conditions at the intake and exhaust port were obtained based on experimental correlations reported by Annand and Hires. Coolant side boundary conditions were based on values reported in the literature. The lower values for the coolant temperature and heat transfer coefficient were used in regions of lower coolant velocity, such as in between cylinder bores.For the stress analysis, only thermal stresses were considered. As mechanical boundary conditions, two points were fixed (∆x=∆y=∆z=0) inside the head bolt hole, and the rigid link method was applied. The gasket contact surface was assumed to be unconstrained.Table 5. Thermal boundary conditionsHeat TransferBoundary Variable 1000rpm 1500rpm 2000rpm 2500rpmI n-cylinder h[W/m2·K]404 502 631 753 T [K] 738 762 786 806Intake port h[W/m2·K]272 350 426 482 T [K] 60 60 60 60Exhaust port h[W/m2·K]778 845 893 960 T [K] 749 810 855 894Coolant h[W/m2·K]4000 to 4500 4000 to 4500 4000 to 4500 4000 to 4500 T [K] 353 to 358 353 to 358 353 to 358 353 to 358FEM MODEL VALIDATION –In order to validate the FEM model, steady-state predictions at selected points of the thermal and stress fields were compared with measurements recorded at the same points. As shown in Fig. 18, measured and predicted steady-state wall temperatures compare favorably over a range of engine speeds, both in magnitude and trend.Comparisons between measured and predicted steadystate stresses are shown in Figs.19 and 20. While the agreement in trend is satisfactory, some differences in magnitude are observed. The discrepancies can be attributed to the following reasons. First, experimental data include the effects of both thermal loading and combustion pressure. On the other hand, only the thermal effect is considered in FEM analysis. Nevertheless, the relatively small difference in magnitudes confirms that the effect of mechanical stresses is relatively small. Second, the stiffness of the firedeck may have been altered due to the strain gage insertion process. Third, the FEM analysis has not accounted for cylinder-by-cylinder variation in boundary conditions due to factors such as manifold gas dynamics, coolant maldistribution, etc. Overall, it is concluded that the FEM model with the applied boundary conditions has the potential to capture the thermal and stress filedwithin the cylinder head with acceptable accuracy.Figure 18. Comparison between measured and predicted steady-state wall temperatures over a rangeof engine speedsFigure 19. Comparison between measured and predicted steady-state stresses near the intake valve,over a range of engine speedsFigure 20. Comparison between measured and predicted steady-state stresses near the exhaust valve,over a range of engine speedsSTEADY-STATE PREDICTIONS OF THERMAL AND STRESS DISTRIBUTIONS –FEM predictions of the steady-state temperature and stress distributions in the firedeck are shown in Fig. 21 for a range of engine speeds at full load. The isotherm plots a-d, on the left hand side Fig. 21, indicate that the region of the firedeck in the vicinity of the exhaust valve seat experiences considerably higher temperatures (80 °C to 100 °C) than the rest of the firedeck. The maximum temperature varies from 232 °C at 1000 rpm to 312 °C at 2500 rpm as a result of increasing mean gas temperature and heat transfer coefficient with increased engine speed. Notice also that as speed is increasing, the hot region propagates from the exhaust valve side to the intake valve side. Outside the firedeck, the cylinder head face experiences temperatures close to the coolant temperature (around 80 °C), independent of speed.It is important to observe that the largest temperature gradients occur between the exhaust valve seat and the injector nozzle hole, and the valve bridge between the two valves. At the two lower engine speeds, the injector nozzle hole and the valve bridge are surrounded by uniformly lower temperatures. However, the propagation of the hot front with increasing speed results in an asymmetric exposure of those critical regions to hot and cold temperatures. It is therefore anticipated that the highest thermal stresses should be concentrated on either the injector hole or the valve bridge region, as thermal stress linearly depends on temperature gradient.(a) Predicted isotherms at 1000 rpm;min = 80 °C, max = 232 °C, increment = 10.1 °C (e) Predicted iso-stress contours at 1000 rpm; min = 3 MPa, max = 251 MPa, increment = 16.5 MPa(b) Predicted isotherms at 1500 rpm;min = 80 °C, max = 263 °C, increment =12.2 °C (f) Predicted iso-stress contours at 1500 rpm; min = 3 MPa, max = 299 MPa, increment = 19.7 MPa(c) Predicted isotherms at 2000 rpm;min = 80 °C, max = 287 °C, increment = 13.8 °C (g) Predicted iso-stress contours at 2000 rpm; min = 5 MPa, max = 354 MPa, increment = 23.3 MPa(d) Predicted isotherms at 2500 rpm;min = 80 °C, max = 312 °C, increment = 15.5 °C (h) Predicted iso-stress contours at 2500 rpm; min = 5 MPa, max = 405 MPa, increment = 26.7 MPaFigure 21. Steady-state temperature [°C] and thermal stress [MPa] distributions of the firedeck.Plots e-h, on the right hand side of Fig. 21, show the predicted thermal stress distributions within the firedeck as Von Mises stress. In general, higher levels of stresses are experienced as speed, gas and wall temperatures increase, consistent with corresponding predictions of the thermal field in the firedeck. Notice however that at every speed, the maximum stress values occur where the maximum temperature gradients (and not where the maximum temperatures) are found. Hence, the location of themaximum thermal stresses is indeed around the injector nozzle hole and the valve bridge region, as suggested from our predictions of the temperature gradients.The maximum stress at those critical locations increases from 251 MPa to 405 MPa, as speed increases from 1000 rpm to 2500 rpm. Given that the yield stress of heat treated cast-iron is around 350 MPa this suggests that regions of the cylinder head may be prone to plastic deformation at conditions over 2,000 rpm and full load. Under severe thermal loading, this plastic deformation would first lead to crack initiation around the nozzle hole and valve bridge. Indeed, Fig. 22 shows that an engine operated under similar conditions developed a crack in the cylinder head firedeck in the region between the injector nozzle hole and the exhaust valve seat, thus validating the numerical predictions. CONCLUSIONSA combined experimental and analytical approach was followed in this work to study stress distributions and causes of failure in diesel cylinder heads under steady-state and transient operation. Experimental studies were conducted first to measure temperatures, heat fluxes and stresses under a series of steady-state and transient operating conditions. Subsequently, a finite element analysis was conducted to predict the detailed steady-state temperature and stress distributions within the cylinder head. The following conclusions can be drawn from our study:Figure 22. Photograph of a typical crack initiation point1. Thermal shock loading plays a role in thermal fatigue, along with steady-state temperature gradients and the level of temperatures. When the engine is turned on or off ，and during periods of changing load at a given speed, the stress level changes significantly. However, a comparison of our steady-state and transient measurements indicates that stresses recorded at any instant during a severe transient are only marginally higher than stresses that would correspond to steady-state operation under each of those conditions. This is attributed to the fact that thermal shock waves penetratefast into the cast-iron cylinder head.2. As engine speed is increased towards the maximum torque speed, the measured steady-state stresses increase or decrease at a faster rate. Beyond the maximum torque speed, the stress variation is slight. The largest temperature gradients occur between the injector nozzle hole and the exhaust valve seat, and valve bridge between two valves. The location of the maximum thermal stress is around the injector nozzle hole and valve bridge region as suggested from prediction of temperature gradients. Hence, under severe thermal loading, the plastic deformation would first lead to crack initiation around the injector nozzle hole and valve bridge.3. A comparison of the predicted steady-state temperatures and stresses compared well with our measurements. Furthermore, the predicted location of the crack initiation point correlated well with experimental observations. This suggests that a validated steady-state FEM stress analysis can play a very effective role in the rapid prototyping of cast-iron cylinder heads.。
外文翻译原文
The artificial lake of Seyhan Dam just north of the city is fed by Seyha n River, which originates from Taurus Mountains. Although the amount of w ater in the dam lake varies with seasons, it is around 1.2×109m3. The water s of Seyhan River leaving the dam flow in north–south direction dividing Ad ana into almost two equal parts.In this study, possibility of using Seyhan River and dam lake as heat so urce and sink is considered. There are many buildings (houses, restaurants, ca fes, offices, shops, small and middlesized industrial establishments, a shoppin g center, a big mosque, a five-star hotel, three hospitals and a university ca mpus) located on the banks of Seyhan River and dam lake. Vertical and hori zontal distances between the buildings and the water are in a range that is s uitable for usage as heat source and sink in heat pumps for many buildings.Thermal behavior of water bodies should be understood before design st age is started [1].However, the thermal characteristics of Seyhan River have not been studied in detail previously.Therefore, a study was initiated to monit or the temperature of Seyhan River. Measurements were taken from the river water downstream of the dam that runs through the city. Initially, the tempe rature of Seyhan River was monitored during a whole day at three different depths (0.25, 0.5 and 1 m from the surface), and it was seen that the tempe rature does not fluctuate considerably during the day. Therefore, it was decid ed to measure the temperature only at a fixed time of the day (around 9:00 h). Influence of the measurement depth is also very slight in the range cover ed. The temperature difference between the minimum and the maximum measThe temperature comparisons shown in Fig. 3, the location of the river and the dam lake with respect to buildings and other parameters considered previously make Seyhan River and dam lake suitable heat source and sink for heat pump applications. However, water has not been used for this purpose at all. In this study the operation of a water-to-air heat pump using the waters of Seyhan River and thedam lake as heat source and sink was investigated experimentally. Air was also used as heat source and sink for comparison purposes.Fig. 3 shows the depth-averaged water temperature obtained from the me asureements performed between November 1999 and November 2000. Also sh own in this figure are the daily minimum, maximum and daily average air te mperatures. The air data were obtained by averaging the measured data for th e years between 1981 and 1996. A constant temperature difference of about 1evident from the figure.The temperature of Seyhan River is almost equal to daily average air te mperature from January to mid-March. With the beginning of heavy rains in mid-March (towards the end of heating season), the water temperature drops below the daily average air temperature, however, still beingh igher than the daily minimum air temperature. The water temperature is about 2–3°C highe r than even the daily average air temperature from mid-November (the begin ning of heating season) to December. It is close to the daily maximum air te mperature. This behavior can be explained in terms of thermal inertia of the lake water. The water temperature starts to decrease and approaches the daily average air temperature at the end of December. It can be concluded in thelight of foregoing analysis that the water temperature is always greater than the daily minimum air temperature and it is around or higher than the daily average air temperature during the whole heating season. This makes Seyhan River a good heat source alternative to air for heating with heat pumps in Adana.When the cooling is considered, the use of Seyhan River is again favorable. The water temperature is always lesser than the daily maximum air temperature during the whole cooling season. It is even smaller than the daily minimum air temperature from the beginning of the cooling season (mid-May) to the beginning of August. The decrease in water temperature in May is due to melting of snow in Taurus Mountains from where Seyhan River originates. In the second half of the cooling season, the water temperature continues to increase while the daily maximum air temperature is still constant at a maximum level and, the daily minimum and daily average air temperatures start decreasing. The water temperature becomes equal to the daily average air temperature at the end of the cooling season. It is obvious that, the water temperature is at least 5 C lower than the maximum air temperature and the difference between the two is as high as 10 C in a significant portion of the cooling season (from mid-May to the beginning of August).Cooling performance and capacity of the heat pump systems that utilize lake or river water as heat sink are accepted as outstanding when entering water temperature is between 13 and 24 C. Performance is good for the entering water temperatures below 29C, and acceptable between 29 and 35 C. If the water temperature is below 13C, direct cooling should be considered [3]. The temperature of Seyhan River is between 17 and 24 C from mid-May to the beginning of August, which is half of the cooling season. In the remaining period, it is always less than 27 C. Therefore, the use of Seyhan River as a heat sink could be very advantageous.The water of Seyhan River and the dam lake is very clean since discharge of pollutants into the river and the dam lake is limited. Because another dam is locatedabout 40 km upstream of Seyhan Dam, there is no uncontrolled flow of river water (flooding) to Seyhan Dam and to the city. Although the water level in the dam lake changes with seasons, the change does not exceed 17 m. The flow rate of the water in the city also varies, however, due to electricity production at the dam, it has a minimum value (2,88 000 m3/h) that is high enough for heat pump applications. These factors enable use of both open and closed-loop heat pump systems.The experimental set-up is shown schematically in Fig. 4. Using the heat pump system shown in the figure a laboratory having the dimensions of 4.3 ×5.8 ×2.2m3 was heated in winter and cooled in summer. The system mainly consists of a vapor-compression heat pump, fan-coils, circulation pumps, flow control valves, auxiliary heat pumps, electrical heaters, temperature controllers, sensors for various measurements and a data collection system.The laboratory is located near the dam lake. However, it is about 67 m above the water level.Therefore, it was not feasible to use lake water directly in the experiments. Instead of using the lake water directly, water tanks were used in the laboratory to model the lake water. One of the water tanks has a capacity of 1000 l and serves as the main heat source and sink in the winter and summer experiments, respectively. In order to keep the temperature of the water returning to the condenser or the evaporator of the heat pump at a fixed desired value, a second water tank with 20-l capacity was also used. Two electric heaters (one in the large tank and the other one in the small tank) and two auxiliary air-source heat pumps (one in the large tank and the other one in the small tank), all controlled by PID temperature controllers, make the fine adjustment of water temperature. The temperature set values were adjusted daily so that the temperature of water returning to the system was constant and equal to that of Seyhan River.The heat pump of the experimental set-up has been designed and constructed originally in the laboratory to produce hot water for domestic use in addition to space heating and cooling. Therefore, the system has three different fluid loops, one for the refrigerant in the heat pump and two for the intermediate medium, which was the water used for the transport of energy from and to evaporator and condenser.However, hot water production was not considered in this study. Experiments were performed in both winter and summer. Heating–cooling changeover is achieved by changing the direction of the transport water by means of four-way valves. For comparison, both air and water were used as heat source and sink in heating and cooling experiments. Three way valves direct the transport water to the fan-coil located outdoors in the air-source–sink experiments or to the water tank in the water-source–sink experiments.In the heating mode, the transport water heated in the condenser is directed to the indoor fancoil where it rejects heat to the conditioned room air. The water follows the path marked with H and circulation is achieved by pump P1. The water cooled in the evaporator also follows the path H and is circulated with the help of pump P2. Water is either directed to the water tank (water-source experiments, WS) where it absorbs heat from the water inside the tank or to the outdoor fan-coil (air-source experiments, AS) where it absorbs heat from the outdoor air. In the cooling mode, the transport water cooled in the evaporator is directed to the indoor fan-coil by means of pump P2. In the indoor fan-coil, the water absorbs heat from the conditioned room air. Heat rejection to the water tank (WS) or to the outdoor air (AS) is achieved by the circulation of transport water by pump P1, between the condenser and the water tank (WS) or the outdoor fan-coil (AS).Refrigerant-22 was used as working fluid in the test heat pump. The hermetic compressor of the system has a nominal rating of 3.2 kW at conditions of 7.2°C evaporating temperature and 54.5°C condensing temperature. Both the condenser and the evaporator of the heat pump are plate type heat exchangers each having 0.088 m2 heat transfer surface area.The output capacity and the input power were obtained to evaluate the performance of the heat pump. Total input power of the system was evaluated from measurement of supply voltage and the current. For this purpose, electronic voltage and current transducers, which produce DC output signals proportional to the voltage and current were employed.Output capacity was determined from temperature and flow rate measurementsof the transport water. Water temperature differences between the inlet and outlet of the condenser and the evaporator were measured using K-type thermocouples inserted into the pipes. To eliminate the errors involved in absolute temperature measurement, thermocouples were arranged so that the resulting output emf is proportional to the temperature difference between the inlet and the outlet. In addition, temperature of the water inside the water tanks, ambient air temperature and the conditioned room temperature were also monitored with the help of thermocouples. An ice bath was employed as the reference junction for all the thermocouples used.Two standard venturimeters, one at the inlet of the evaporator and the other one at the inlet of the condenser, and two differential pressure transducers were used for the flow rate measurements of the transport water. All the outputs of the measurement sensors were monitored continuously with a sampling rate of 10 readings/s, using a computer-controlled data logging system. The system has a 16-bit analogue-to-digital conversion unit.The heating and the cooling performances of the heat pump were calculated, respectively, from the following equations:COP heat =..tot c W Q =.....,,.)(.otherfans pumps comp ci tw ce tw tw tw W W W W T T c m +++- (1) COP cool =..tot e W Q =.....,,..)(.other fans pumps comp ee tw ei tw tw tw W W W W T T c m ++- (2)where Q ˙cand Q ˙eare, respectively, the amount of the heat subtracted from the condenser and added to the evaporator by the transport water, W ˙ tot the total power consumption of the system, and m ˙tw and ctw show, respectively, mass flow rate and specific heat of the transport water. Ttw,ci, Ttw,ce, Ttw,ei, Ttw,ee are, respectively, temperature of the transport water at the condenser inlet and exit and at the evaporator inlet and exit.It should be noted that, in Eqs. (1) and (2), W ˙ tot includes the power to the pumps (W ˙ pumps) used for circulation of the transport water and to the fans(W˙ fans) of the indoor fan-coil unit and outdoor fan-coil units (if it is used) and power to the control valves (three- and four-way solenoid valves), in addition to the power consumption of the compressor (W˙ comp) of the heat pump. However, it does not include the energy consumption of the heaters, the heat pumps and the temperature controllers used for keeping the temperature of the water constant in the water tanks. In watersource– sink experiments, the outdoor fan-coil unit is not used and, therefore, the fan power of the outdoor unit was taken as zero.Uncertainty of the measurements was estimated to be 0.3 C for temperature, 2% for flow rate, and 1% for supply voltage and current. The uncertainty associated with COP was calculated following Ref. [11]. The maximum uncertainty in COP was found to be 11.7% for air-source– sink experiments and 7.4% for water-source–sink experiments.Two separate sets of experiments were performed. Heating experiments were carried out in the winter of 2000 (from January to March) and cooling experiments in the summer of 2000 (from May to August). Both air and water were utilized as heat source and sink in two sets.Temperature of Seyhan River (Fig. 3) varies between 8 and 20 C during the heating season. Therefore, water-source heating experiments were carried out for source temperatures of between 8 and 20 C. Although it was possible to adjust the entering water temperature at any desired value (Fig. 4), there was no control for the entering air temperature in the case of air-source experiments. The ambient air temperature varies with time during a day and it may also exhibit fluctuations (Fig. 5).Therefore, after obtaining variation of values with time during the air experiments, mean values were calculated and used in the analysis. The air-source heating experiments were carried out for the mean air temperatures between 6 and 20 C.Figs. 5 and 6 present typical results obtained from the air-source and the water-source heating experiments, respectively. In these figures, variation of temperature of the transport water with time during the experiments is shown. It is clear from Fig. 6 that the temperature of the transport water at the evaporator inlet is constant and does not exhibit considerable fluctuations. This proves that the temperature control system of the water tanks operates properly. The system reaches smoothly steady-state condition after a period of about half an hour. The temperatures obtained in the case of air-source experiments (Fig. 5) exhibit fluctuations and the variations are not as smooth as seen in the water-source experiments. This is due to variation and fluctuation of ambient air temperature.Fig. 7 presents the mean COP values obtained from the heating experiments performed with various water and air temperatures. COPheat was calculated from Eq. (1). As expected, with the increase of source temperature (Tsource), COPheat increases for both sources. A least-square, linear curve fit to the data points yields the following equations:It is evident from Fig. 7 that, COPheat in the water-source experiments is about 15–40% higher than that of the air-source experiments for the samesource-temperature. This is mainly due to absence of power consumption of the outdoor fan-coil unit (not used) and direct heat exchange between the source (thewater within the tanks) and the refrigerant in the evaporator in the case ofwater-source experiments. In the water-source experiments, the water taken from the water tanks is circulated through the liquid-side of the evaporator. However, in the air-source experiments, the outdoor unit operates (the fan consumes energy) and the heat transfer between the source (ambient air) and the refrigerant in the evaporator is achieved by means of the transport water that circulates between the liquid-side of the evaporator and the outdoor fan-coil unit. This results in a less effective heat transfer and COPheat is reduced. However, in real water-source–sink applications, there will be a pump to circulate the water between the water source (lake, river, etc.) and heat pump system and the COP will decrease proportionally with the power consumption of the pump. This is valid for both heating and cooling modes. On the other hand, the power consumption of the pump is proportional to the distance and the elevation between the water source and the system. Therefore, feasibility of utilizing water as heat source–sink in heat pump systems depends on the distance and the elevation between the water source and the building. Suitability of using water as heat source–sink in heat pump systems should be decided separately for each building. However, as a rough guide, the performance of the water-source–sink heat pump units is reduced by 15–25% in order to take into account of pumping power [3]. If this approach is applied to the water-source results obtained, Eq. (3) will produce COPheat values close to that of Eq. (4) which was obtained from the air-source data.Fig. 8 shows COPheat values calculated using Eq. (4), which was obtained from the air-source data considering the whole heating season. Eq. (4), instead of Eq. (3), was also used for the water in order to take into account the power consumption of the pumps in real applications. The daily minimum, maximum and daily average air temperatures were used as the source temperature in the case of air source. As discussed previously, the temperature of Seyhan River is always greater than the daily minimum air temperature and it is around or higher than the daily average air temperature during the whole heating season (Fig. 3). Reflection of this trend can be seen in terms of COPheat (Fig. 8). COPheat of water source is around or higher than COPheat calculated using daily average air temperature except at the end of the heating season (from mid-March to the end of April). However, even in this period, COPheat of water is better if the daily minimum air temperature is considered. Use of water as heat source is very beneficial especially at the beginning of the heating season (from mid-November to the beginning of January) during which COPheat of water approaches that of daily maximum air temperature. However, the pumping power requirement of a particular application should also be considered. It is clear that usage of water will eliminate defrosting and its negative consequences such as reduced capacity, performance and comfort conditions.Cooling experiments were performed for sink temperatures in the range of20–40 C for water and, 22–40 C for air. Fig. 9 shows the results of the coolingexperiments performed with various water and air temperatures. COPcool was calculated from Eq. (2). It is seen that COPcool decreases with increasing sink temperature (Tsink) for both cases. A least-square, linear curve fit to the data points yields the following equations:Similar to the results of the heating experiments, the water-sink experiments yield about 35–40% higher COPcool values than that of the air-sink experiments for the same sink temperature.Fig. 8 shows COPcool values calculated using Eq. (6) which was obtained from the air-sink data considering the whole cooling season. Eq. (6), instead of Eq. (5), was also used for the water in order to take into account the power consumption of the pumps in real applications. The daily minimum, maximum and daily average air temperatures were used as the sink temperature in the case of air.In the first half of the cooling season (from mid-May to the beginning of August), Seyhan River temperature is lower than the daily minimum air temperature, and it is lower or around the daily average air temperature for the rest of the season (Fig. 3). Therefore, usage of water instead of air as heat sink could be advantageous especially in the first half of the cooling season during which COPcool of water is very close to that of the daily minimum air temperature (Fig. 8). Even in the second half of the cooling season, COPcool of water is better than that of the daily average air temperature. The pumping power requirement of a particular application should be considered again when deciding on a suitable sink.The air data for Adana, between 1981 and 1996, which were obtained from the DMI˙ were analyzed to obtain daily minimum, maximum and daily average temperatures and heating and cooling degree-days, for Adana. Temperature of Seyhan River was measured from November 1999 to November 2000. The suitability of using Seyhan River as heat source–sink for heat pumps was discussed by comparing the air and water data and by considering other related parameters.Analysis of the results of the experimental study that was carried out using a heat pump system which was capable of utilizing both air and water as heat source-sink revealed that use of Seyhan River instead of ambient air could be advantageous duringthe whole heating and cooling seasons except at the end of heating season (from mid-March to the end of April). The usage of water is very attractive especially at the beginning of the heating and cooling seasons. It is possible to design heat pump systems that use more than one heat source–sink [12]. These systems can utilize water as the primary heat source–sink, but is changed over to extract heat from air (or discharge heat to air). They should be supported by an intelligent control system that first decides which source–sink is more economic, evaluating the data (measured or default) for temperature of the source–sink and for energy consumption of the auxiliary units such as fans and pumps. After this stage, the intelligent control system produces control signals for automatically controlled units for source–sink change over. The main disadvantage of the heat pump systems that can utilize more than one heat source–sink is their higher initial cost than that of simple heat pumps.Considering the rapid growth of Tur key’s energy consumption and imports in recent years, usage of heat pump systems for heating and cooling and usage of water resources in these systems where it is more economic than air (as it is the case for Adana) should be encouraged.。
外文翻译实例
Literature Topic：Selection attributes of wedding banquet venues: An exploratory study of HongKong prospective wedding couplesTranslationofIntroductionofThePaper：作为中式婚礼的重要组成部分，婚宴一般在专门的宴会设施上举行。
这是一个精心设计的、高花销的场所，新人在这里宣告彼此喜结良缘，同时也回馈亲朋好友的善意祝福。
传统意义上来说，作为邀请众多宾客参与的一项私人事件，婚宴是在婚礼或前往政府婚姻机构完成注册手续和领取结婚证后举办的（Choi，2002）。
不可置否，婚宴市场在近几年确实有所拓展。
据香港政府统计处（简称HKCSD）的资料显示，自2002年以来，婚姻数量不断增长，截止2007年已达到47,500例（HKCSD，2008）。
婚宴对新人来说是最大的一笔婚礼开支，而中餐厅及酒店宴会厅则是最受欢迎的婚宴场地。
高价位宴会活动的需求增多对美国酒店餐饮部门的整体利润的显著增长贡献不少，如婚宴的举办（Adler and Chien，2004）。
美国的一项研究也表明，至少70%的酒店餐饮利润来自于宴会活动，而其中又有50%的宴会活动是出于婚宴的需求（Marsan，2000）。
据由香港旅游发展局（简称HKTB）编写的香港酒店业摘要所称，香港酒店餐饮部门的利润自2003年到2007年稳定增长至11.6亿美元（1美元=7.8港币），相当于整体酒店利润的30%（HKTB，2004，2005，2006，2007，2008）。
由公私合营的电子平台ESDlife近年来所主持的调查显示，仅在婚宴这一项目开支上，平均每对新人愿意花费15,900美元（ESDlife，2007）。
每年在香港，婚宴业务的营业额就达到了7.55亿美元。
为了在这片高利润市场上获得足够的吸引力，宴会经理不断推陈出新，为准新人提供多种套餐，包括特别的额外服务例如婚宴当晚的免费套房、为宾客提供足够的停车场地、到处美丽的鲜花装饰等。
外文文献翻译原文+译文
外文文献翻译原文Analysis of Con tin uous Prestressed Concrete BeamsChris BurgoyneMarch 26, 20051、IntroductionThis conference is devoted to the development of structural analysis rather than the strength of materials, but the effective use of prestressed concrete relies on an appropriate combination of structural analysis techniques with knowledge of the material behaviour. Design of prestressed concrete structures is usually left to specialists; the unwary will either make mistakes or spend inordinate time trying to extract a solution from the various equations.There are a number of fundamental differences between the behaviour of prestressed concrete and that of other materials. Structures are not unstressed when unloaded; the design space of feasible solutions is totally bounded；in hyperstatic structures, various states of self-stress can be induced by altering the cable profile, and all of these factors get influenced by creep and thermal effects. How were these problems recognised and how have they been tackled?Ever since the development of reinforced concrete by Hennebique at the end of the 19th century (Cusack 1984), it was recognised that steel and concrete could be more effectively combined if the steel was pretensioned, putting the concrete into compression. Cracking could be reduced, if not prevented altogether, which would increase stiffness and improve durability. Early attempts all failed because the initial prestress soon vanished, leaving the structure to be- have as though it was reinforced; good descriptions of these attempts are given by Leonhardt (1964) and Abeles (1964).It was Freyssineti’s observations of the sagging of the shallow arches on three bridges that he had just completed in 1927 over the River Allier near Vichy which led directly to prestressed concrete (Freyssinet 1956). Only the bridge at Boutiron survived WWII (Fig 1). Hitherto, it had been assumed that concrete had a Young’s modulus which remained fixed, but he recognised that the de- ferred strains due to creep explained why the prestress had been lost in the early trials. Freyssinet (Fig. 2) also correctly reasoned that high tensile steel had to be used, so that some prestress would remain after the creep had occurred, and alsothat high quality concrete should be used, since this minimised the total amount of creep. The history of Freyssineti’s early prestressed concrete work is written elsewhereFigure1:Boutiron Bridge,Vic h yFigure 2: Eugen FreyssinetAt about the same time work was underway on creep at the BRE laboratory in England ((Glanville 1930) and (1933)). It is debatable which man should be given credit for the discovery of creep but Freyssinet clearly gets the credit for successfully using the knowledge to prestress concrete.There are still problems associated with understanding how prestressed concrete works, partly because there is more than one way of thinking about it. These different philosophies are to some extent contradictory, and certainly confusing to the young engineer. It is also reflected, to a certain extent, in the various codes of practice.Permissible stress design philosophy sees prestressed concrete as a way of avoiding cracking by eliminating tensile stresses; the objective is for sufficient compression to remain after creep losses. Untensionedreinforcement, which attracts prestress due to creep, is anathema. This philosophy derives directly from Freyssinet’s logic and is primarily a working stress concept.Ultimate strength philosophy sees prestressing as a way of utilising high tensile steel as reinforcement. High strength steels have high elastic strain capacity, which could not be utilised when used as reinforcement; if the steel is pretensioned, much of that strain capacity is taken out before bonding the steel to the concrete. Structures designed this way are normally designed to be in compression everywhere under permanent loads, but allowed to crack under high live load. The idea derives directly from the work of Dischinger (1936) and his work on the bridge at Aue in 1939 (Schonberg and Fichter 1939), as well as that of Finsterwalder (1939). It is primarily an ultimate load concept. The idea of partial prestressing derives from these ideas.The Load-Balancing philosophy, introduced by T.Y. Lin, uses prestressing to counter the effect of the permanent loads (Lin 1963). The sag of the cables causes an upward force on the beam, which counteracts the load on the beam. Clearly, only one load can be balanced, but if this is taken as the total dead weight, then under that load the beam will perceive only the net axial prestress and will have no tendency to creep up or down.These three philosophies all have their champions, and heated debates take place between them as to which is the most fundamental.2、Section designFrom the outset it was recognised that prestressed concrete has to be checked at both the working load and the ultimate load. For steel structures, and those made from reinforced concrete, there is a fairly direct relationship between the load capacity under an allowable stress design, and that at the ultimate load under an ultimate strength design. Older codes were based on permissible stresses at the working load; new codes use moment capacities at the ultimate load. Different load factors are used in the two codes, but a structure which passes one code is likely to be acceptable under the other.For prestressed concrete, those ideas do not hold, since the structure is highly stressed, even when unloaded. A small increase of load can cause some stress limits to be breached, while a large increase in load might be needed to cross other limits. The designer has considerable freedom to vary both the working load and ultimate load capacities independently; both need to be checked.A designer normally has to check the tensile and compressive stresses, in both the top and bottom fibre of the section, for every load case. The critical sections are normally, but not always, the mid-span and the sections over piers but other sections may become critical ，when the cable profile has to be determined.The stresses at any position are made up of three components, one of which normally has a different sign from the other two; consistency of sign convention is essential.If P is the prestressing force and e its eccentricity, A and Z are the area of the cross-section and its elastic section modulus, while M is the applied moment, then where ft and fc are the permissible stresses in tension and compression.c e t f ZM Z P A P f ≤-+≤Thus, for any combination of P and M , the designer already has four in- equalities to deal with.The prestressing force differs over time, due to creep losses, and a designer isusually faced with at least three combinations of prestressing force and moment;• the applied moment at the time the prestress is first applied, before creep losses occur,• the maximum applied moment after creep losses, and• the minimum applied moment after creep losses.Figure 4: Gustave MagnelOther combinations may be needed in more complex cases. There are at least twelve inequalities that have to be satisfied at any cross-section, but since an I-section can be defined by six variables, and two are needed to define the prestress, the problem is over-specified and it is not immediately obvious which conditions are superfluous. In the hands of inexperienced engineers, the design process can be very long-winded. However, it is possible to separate out the design of the cross-section from the design of the prestress. By considering pairs of stress limits on the same fibre, but for different load cases, the effects of the prestress can be eliminated, leaving expressions of the form:rangestress e Perm issibl Range Mom entZ These inequalities, which can be evaluated exhaustively with little difficulty, allow the minimum size of the cross-section to be determined.Once a suitable cross-section has been found, the prestress can be designed using a construction due to Magnel (Fig.4). The stress limits can all be rearranged into the form:()M fZ PA Z e ++-≤1 By plotting these on a diagram of eccentricity versus the reciprocal of the prestressing force, a series of bound lines will be formed. Provided the inequalities (2) are satisfied, these bound lines will always leave a zone showing all feasible combinations of P and e. The most economical design, using the minimum prestress, usually lies on the right hand side of the diagram, where the design is limited by the permissible tensile stresses.Plotting the eccentricity on the vertical axis allows direct comparison with the crosssection, as shown in Fig. 5. Inequalities (3) make no reference to the physical dimensions of the structure, but these practical cover limits can be shown as wellA good designer knows how changes to the design and the loadings alter the Magnel diagram. Changing both the maximum andminimum bending moments, but keeping the range the same, raises and lowers the feasible region. If the moments become more sagging the feasible region gets lower in the beam.In general, as spans increase, the dead load moments increase in proportion to the live load. A stage will be reached where the economic point (A on Fig.5) moves outside the physical limits of the beam; Guyon (1951a) denoted the limiting condition as the critical span. Shorter spans will be governed by tensile stresses in the two extreme fibres, while longer spans will be governed by the limiting eccentricity and tensile stresses in the bottom fibre. However, it does not take a large increase in moment ，at which point compressive stresses will govern in the bottom fibre under maximum moment.Only when much longer spans are required, and the feasible region moves as far down as possible, does the structure become governed by compressive stresses in both fibres.3、Continuous beamsThe design of statically determinate beams is relatively straightforward; the engineer can work on the basis of the design of individual cross-sections, as outlined above. A number of complications arise when the structure is indeterminate which means that the designer has to consider, not only a critical section,but also the behaviour of the beam as a whole. These are due to the interaction of a number of factors, such as Creep, Temperature effects and Construction Sequence effects. It is the development of these ideas whichforms the core of this paper. The problems of continuity were addressed at a conference in London (Andrew and Witt 1951). The basic principles, and nomenclature, were already in use, but to modern eyes concentration on hand analysis techniques was unusual, and one of the principle concerns seems to have been the difficulty of estimating losses of prestressing force.3.1 Secondary MomentsA prestressing cable in a beam causes the structure to deflect. Unlike the statically determinate beam, where this motion is unrestrained, the movement causes a redistribution of the support reactions which in turn induces additional moments. These are often termed Secondary Moments, but they are not always small, or Parasitic Moments, but they are not always bad.Freyssinet’s bridge across the Marne at Luzancy, started in 1941 but not completed until 1946, is often thought of as a simply supported beam, but it was actually built as a two-hinged arch (Harris 1986), with support reactions adjusted by means of flat jacks and wedges which were later grouted-in (Fig.6). The same principles were applied in the later and larger beams built over the same river.Magnel built the first indeterminate beam bridge at Sclayn, in Belgium (Fig.7) in 1946. The cables are virtually straight, but he adjusted the deck profile so that the cables were close to the soffit near mid-span. Even with straight cables the sagging secondary momentsare large; about 50% of the hogging moment at the central support caused by dead and live load.The secondary moments cannot be found until the profile is known but the cablecannot be designed until the secondary moments are known. Guyon (1951b) introduced the concept of the concordant profile, which is a profile that causes no secondary moments; es and ep thus coincide. Any line of thrust is itself a concordant profile.The designer is then faced with a slightly simpler problem; a cable profile has to be chosen which not only satisfies the eccentricity limits (3) but is also concordant. That in itself is not a trivial operation, but is helped by the fact that the bending moment diagram that results from any load applied to a beam will itself be a concordant profile for a cable of constant force. Such loads are termed notional loads to distinguish them from the real loads on the structure. Superposition can be used to progressively build up a set of notional loads whose bending moment diagram gives the desired concordant profile.3.2 Temperature effectsTemperature variations apply to all structures but the effect on prestressed concrete beams can be more pronounced than in other structures. The temperature profile through the depth of a beam (Emerson 1973) can be split into three components for the purposes of calculation (Hambly 1991). The first causes a longitudinal expansion, which is normally released by the articulation of the structure; the second causes curvature which leads to deflection in all beams and reactant moments in continuous beams, while the third causes a set of self-equilibrating set of stresses across the cross-section.The reactant moments can be calculated and allowed-for, but it is the self- equilibrating stresses that cause the main problems for prestressed concrete beams. These beams normally have high thermal mass which means that daily temperature variations do not penetrate to the core of the structure. The result is a very non-uniform temperature distribution across the depth which in turn leads to significant self-equilibrating stresses. If the core of the structure is warm, while the surface is cool, such as at night, then quite large tensile stresses can be developed on the top and bottom surfaces. However, they only penetrate a very short distance into the concrete and the potential crack width is very small. It can be very expensive to overcome the tensile stress by changing the section or the prestress。
外文文献翻译范例
As designed by architect Bruce Graham and engineer Fazlur Khan of the Chicago office of Skidmore Owings and Merrill (SOM), the structure was a "bundled tube" system of nine squares with sides of 75 feet (for an overall 225 x 225 ft), sheathed in a curtain wall of dark tinted glass. Above the fiftieth floor, some squares dropped away as the tower rose to create smaller floor plates and a distinctive stepped silhouette.
正如建筑师和工程师Bruce Graham，Fazlur Khan of Skidmore, Owings and Merrill.（SOM）的芝加哥办公室设计，结构为（225 x为一整体225英尺）一个“绑定圆管状造型”的九个方面的75英尺广场系统，嵌装在一个深色玻璃幕墙。五十层以上，有的就离开广场的塔上升到创建更小的地板加强板和独特的剪影。
外文翻译格式范例
由于这种类型的脆弱性所造成的损害，可以很深刻的，尽管这会取决于该应用软 件与数据库关联的特权级别。如果该软件以管理者类型权限访问数据，然后恶意 运行命令也会是这一级别的访问权限，此时系统妥协是不可避免的。还有这个问 题类似于操作系统的安全规则，在那里，项目应该以最低的权限运行，而且这是 必要的。如果是正常的用户访问，然后启用这个限制。 同样的问题，SQL 的安全也不完全是一个数据库的问题。特定的数据库命令或 要求，不应该允许通过应用层。这是可以通过"安全码"的方式加以预防的。这是 一个场外话题，但应该被应用的一些基本步骤的详细设计是有必要的。 第一步，在获取任何申请时须验证和控制用户输入。可能的情况下，严格的 类型应被设定以控制具体数据（例如，期望得到数值数据，字符串类型数据等）， 并在可能实现的情况下，如果数据是以字符型为基础的，需要禁止特定的非字母 数字字符。如果这是不能实现的，应该做出争取使用替代字符的考虑（例如，使 用单引号，这在 SQL 命令中时通常被使用的）。 在使用您的组织时具体的与安全有关的编码技术应加入编码标准。如果所有 开发商都使用相同的基线标准，特定具体的安全措施，这将大大减少 SQL 注入妥 协的风险。 能够使用的另一种简单的方法，是清除数据库中不再需要的所有程序。这些 限制了数据库中不再需要的或者多于过剩的被恶意利用的程度。这类似于消除操 作系统内不需要的服务程序，是一种常见的安全实践。
◆
Common sense security
Before we discuss the issues relating to database security it is prudent to high- light the
译文标题 原文标题 作 者
英语林译版范文参考示例
英语林译版范文参考示例When I was a child, I used to spend a lot of time playing in the park near my home. The park was a magical place for me, full of adventures and new discoveries. I would spend hours exploring the woods, climbing trees, and playing on the swings.One of my favorite activities in the park was feeding the ducks at the pond. I would bring a bag of stale bread from home and sit by the water, watching the ducks paddle around and eagerly gobble up the crumbs I tossed to them. It was a simple pleasure, but one that brought me immense joy.As I grew older, my visits to the park became less frequent. I became preoccupied with school, friends, andother activities, and the park gradually faded into the background of my life. However, in recent years, I have foundmyself drawn back to the park and its familiar sights and sounds.Now, as an adult, I appreciate the park in a different way. I no longer climb trees or play on the swings, but Istill find solace in the peaceful surroundings and the beauty of nature. I often take walks around the pond, enjoying the company of the ducks and the soothing sound of the water.The park holds a special place in my heart, and I am grateful for the memories and experiences it has given me over the years. It is a place of nostalgia and tranquility, a sanctuary from the hustle and bustle of everyday life. I am determined to continue visiting the park, to find comfort and joy in its familiar embrace.。
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HTML5的攻击脚本介绍报告介绍本文是通过使用新的网页标准-HTML5，来设计用于可能的新类型适用环境.之后先从HTML5的介绍开始到相关的适用范围进行讲解。
什么是HTML5？HTML5是一种新的简单的新功能，为了适用于发展中的应用，同时提供了HTML4中现存的功能。
它是一种为了提高现有语言的多媒体和通信支持能力而特别设计的，可以使网页开发者的工作更加简单。
HTML5当新的软件版本公布后，和HTML4相比，它就不只是新版本这么简单了。
它包括补充了现有网页标准的全部小细节；比如当前每个浏览器的插件，但不包括所有的功能。
虽然最后我们都期望所有浏览器都有相似的一组功能，但这也会意味着不存在“HTML5标准”了。
HTML5的实施现状的可以从维基百科中看到各浏览器的占有比率。
实际的HTML5对于运用到任何网站上都需要事先亲自读取。
需要注意的是,这些仍在积极开发。
我们可以用HTML5做些什么？用HTML5我们到底能做什么？HTML语言已经发展很久了，但其中的框架部分仍然是大家最喜欢的。
HTML标签,它已经迅速的变得烦人了。
为了说明这一点,可以参考在2000年的的截图和现在的截图对比。
今天的现代网站挤满了JavaScript,层叠样式表(CSS),Flash,AJAX等很多其他技术。
网络互动媒体的今天，HTML5将超越这些。
它不仅会使今天的web页面的所有功能实现变得更简单,而且它将添加一大堆额外功能。
举一个例子来表现一下的HTML5的小部分强大新功能,Google的工程师移植三个著名的第一人称射击游戏(FPS)游戏：“地震。
二世”。
这两个游戏完全为HTML5代码构成。
所有的3 d图形,运行,本地保存游戏,和其他亮点完全被写在HTML代码和一些JavaScript里。
然而,并不是每一个网站会将使用所有功能,但让我们看看一个例子:HTML5现在可以使开发人员的工作更简单。
下面是一个你每天在互联网上看到的例子。
这是一个简单的表单,允许人们输入他们的电子邮件地址。
Web开发人员要确保用户在文本字段中输入有效的电子邮件地址,之后用户单击SUBmit按钮提交地址需要使用JavaScript 代码。
这段代码使用一个模式称为“正则表达式”,确保用户输入的文本看起来像是有效的电子邮件地址。
虽然前面的代码不是很混乱,但看起来还是不整洁。
想象有一个表单,需要一个名字,一个电子邮件地址,电话号码,出生日期,和一个主页,所有项目都需要一个单独的JavaScript代码验证，这并不理想。
让我们看看下面的代码相同的页面使用HTML5后表现出的一些不同的特性。
页面相同的功能(即验证电子邮件地址),经过整理后可以看出并没有使用JavaScript。
验证警告比之前的例子的弹出消息装口更好看。
这是怎么发生的呢?它实际上是相当简单的。
在前面的示例中,我们告诉浏览器用户可以通过数据输入来输入文本字段,。
浏览器愉快地为我们呈现的文本字段,然后我们使用JavaScript来确保用户输入的文本确实是电子邮件地址。
HTML5有一个新的输入类型称为“电子邮件”这告诉我们想要的浏览器用户能够输入电子邮件地址。
浏览器像呈现普通文本字段一样呈现这个输入电子邮件地址的要求,并达成我们所需要的验证。
其他新类型,如“电话”“url”“日期”和“数量”也存在。
我们只是简单的介绍下HTML5的小部分功能。
以上显示了在iPhone上电子邮件字段是什么样子。
因为浏览器知道这是一个电子邮件字段,它给用户提供了@按钮和空间来方便地操作。
如果字段是一个电话号码,键盘就会显示数字而不是字母字符。
通过使用HTML5，之前我们看到的攻击是可能实现的,让我们看看一个HTML5 可以实现的——办公应用。
HTML5直接引入了在浏览器的本地存储。
让我们通过下面的例子看看这意味着什么：在工作时,你打开你最喜欢的web应用程序,比如游戏,然后开始玩。
当你游戏的时候,编码是完全通过HTML5运行的,它通过调用你的浏览器本地存储来节省你的程序运行时间。
当突然断开时网络连接时，你仍然可以继续在下班回家的火车上玩。
当你完成每个关卡,您的浏览器更新到当前进度。
只要你一到家，你的浏览器和系统就会马上关闭。
那天晚上,你重新启动系统,连接到互联网,并再次玩这个游戏。
因为你所有的设置都存储在您的浏览器中,你开始在哪里你离开,因为你是在线游戏悄悄在后台更新(例如,拉下一些新的水平包或更新你的全球高分)。
到了晚上，你重新启动系统,连接到互联网,并再次玩这个游戏。
因为你所有的设置都存储在您的浏览器中,从你离开的地方开始,因为你在线游戏悄悄在后台更新(例如,下载的关卡包或更新你的分数记录)。
在线和移动应用程序,这意味这办公软件,和任何其他应用程序也可以实现这些功能?想了解HTML5和云计算为什么会有如此巨大的潜力,可以在以下网站:看看互动演示的HTML5的所有功能。
（net tuts +:28个HTML5特性,技巧,以及你必须知道6个技术；:HTML5的7个示范）执行概要:HTML5攻击样本现在你知道一些关于HTML5的新的特性和强大功能,让我们看看实施者如何滥用这些去“攻击”无辜的网民。
在了解如何实施的每个细节前,让我们先看看完整的攻击场景。
注意,除了提供更多细节,本文的实现细节部分包含几个例子,不包括完整的实现场景。
我们只讨论每个高级实现效果的完整实现场景。
每个样本和其他非相关实现将在稍后说明。
攻击计划在这种实现场景中，Acme Inc付钱给黑客入侵到竞争对手的网络中。
Acme和Bravo 是两个全球最大的在线购物网站。
作为协议的一部分，Acme交给黑客的命令如下：尽可能和Bravo网络妥协。
尽可能多的提取登录凭证和其他个人资料。
提供一个详细的图标,标明Bravo网络所有的机器,服务和漏洞。
使用这个权限操作能以某种方式破坏Bravo品牌。
一旦操作完成,不会留下任何痕迹。
双方商定的费用500000美元，为一个特定的时间范围内让Mr.HAcker（以下以黑客代称）完成任务。
来进行这次袭击。
阶段1:侦察在第一阶段,攻击者的目的是发现尽可能多的情报，关于目标--Bravo。
根据经验,黑客发现大公司只有几个网络的漏洞。
于是,他开始着眼与公司最薄弱的环节，它的员工。
使用Maltego8 和Google之类的搜索引擎工具，攻击者通过许多公共网站，包括LinkedIn,Facebook, and Google+设立了一个列有Bravo公司员工档案的列表。
黑客还注意到Bravo使用了支持广泛的操作系统和平台，例如Windows、Linux、Mac OS X和所有出现的，还有安卓设备及iPads or iPhones。
因此,他选择了使用JavaScript--一个公共语言,来进行这次袭击。
攻击者还注意到10个Bravo的员工是一个定期特定车主论坛的成员。
这个论坛似乎有一些安全问题所以他也选择这是他最初的入侵目标。
阶段2:滩头阵地黑客选择使用老式汽车网站作为攻击的初始点,以获得一个对付Bravo的滩头阵地。
他注意到该网站的搜索页面是容易受到跨站点脚本(XSS)的攻击,这将允许他嵌入自己的定制JavaScript，每次有人访问该网站都会加载。
他确定按这个老办法使网站显示一个消息框选择,证明他可以控制他选择要运行的JavaScript代码。
老式汽车网站已经采取措施防止XSS，但其管理员没有意识到HTML5会引入大量新途径导致黑客来完成这样的攻击,而且他们的过滤器没有准备好防御措施。
对于真正的攻击代码,攻击者花了一些时间进行研究和开发一套先进的攻击target-Bravo专门创建的。
根据他的侦察,攻击者知道布拉沃很好的浏览器利用检测器,一个。
优秀file-scanning防病毒解决方案,以及最新的和最先进的网络入侵检测系统(IDS)。
对于真正的攻击代码,攻击者花了一些时间进行专门创建研究开发一套为对付他的目标Bravo。
根据他的侦察,攻击者知道Bravo有很好的浏览器开发工具。
优秀文件略读防病毒解决方案,以及最新的和最先进的网络入侵检测系统(IDS)。
考虑到这一点，黑客开发一套先进的体系但相对容易发展攻击,只会存在于浏览器而且永远不会接触到磁盘。
它是高度多态，所以网络id将没有机会来阻止它。
它也不会使用任何开发者工具。
相反,它只会利用浏览器的新特性，包括在HTML5条件下。
最后,脚本只会被老式汽车网站含有Bravo的IP触发。
阶段3:获得许可一旦最初的受害者的系统已经泄露,攻击者使用现成的代码将会被Andlabs org项目研究人员称为“未来的壳”这个工具箱是完全用HTML和JavaScript编写以及利用新网页接口HTML5和跨源请求(COR)的特性来创建两台机器之间的双向网络连接。
这样做允许攻击者指示受害者的机器无形浏览互联网与相同的访问权限的用户。
这意味着攻击者完全相同的访问权限为用户邮箱账户,内部网站点,等等使用这个工具,攻击者已经完美的双向沟通的平台。
他可以发出一个命令,所有10个最初被感染的机器,不管操作系统或平台是否在线。
这样做允许攻击者无形中享有受害者的机器浏览互联网时相同的访问权限。
这意味着攻击者可以以完全相同的访问权限访问用户邮箱账户,内部网站点,等等。
使用这个工具,攻击者已经完美构建的双向沟通的平台。
他可以发出一个命令,所有10个最初被感染的机器,不管操作系统或平台是否在线都必须执行。
所有的通信发生在标准网络,很容易穿过防火墙。
下一步是履行与Acme合同的第一部分-最大化损坏和感染尽可能多的机器。
为了做到这一点,攻击者必须首先建立一个Bravo的网络地图。
阶段4:网络扫描HTML5的一个特性是能够使直接连接在任何端口到任何机器。