论文翻译及原文
毕业论文(设计)外文文献翻译及原文
金融体制、融资约束与投资——来自OECD的实证分析R．SemenovDepartment of Economics，University of Nijmegen，Nijmegen（荷兰内梅亨大学，经济学院）这篇论文考查了OECD的11个国家中现金流量对企业投资的影响.我们发现不同国家之间投资对企业内部可获取资金的敏感性具有显著差异,并且银企之间具有明显的紧密关系的国家的敏感性比银企之间具有公平关系的国家的低.同时，我们发现融资约束与整体金融发展指标不存在关系.我们的结论与资本市场信息和激励问题对企业投资具有重要作用这种观点一致，并且紧密的银企关系会减少这些问题从而增加企业获取外部融资的渠道。
一、引言各个国家的企业在显著不同的金融体制下运行。
金融发展水平的差别(例如，相对GDP的信用额度和相对GDP的相应股票市场的资本化程度），在所有者和管理者关系、企业和债权人的模式中，企业控制的市场活动水平可以很好地被记录.在完美资本市场,对于具有正的净现值投资机会的企业将一直获得资金。
然而，经济理论表明市场摩擦，诸如信息不对称和激励问题会使获得外部资本更加昂贵，并且具有盈利投资机会的企业不一定能够获取所需资本.这表明融资要素，例如内部产生资金数量、新债务和权益的可得性，共同决定了企业的投资决策.现今已经有大量考查外部资金可得性对投资决策的影响的实证资料（可参考，例如Fazzari（1998）、 Hoshi(1991)、 Chapman（1996）、Samuel(1998））.大多数研究结果表明金融变量例如现金流量有助于解释企业的投资水平。
这项研究结果解释表明企业投资受限于外部资金的可得性。
很多模型强调运行正常的金融中介和金融市场有助于改善信息不对称和交易成本，减缓不对称问题,从而促使储蓄资金投着长期和高回报的项目,并且提高资源的有效配置（参看Levine（1997)的评论文章）。
因而我们预期用于更加发达的金融体制的国家的企业将更容易获得外部融资.几位学者已经指出建立企业和金融中介机构可进一步缓解金融市场摩擦。
毕业论文外文翻译(中英文)
译文交通拥堵和城市交通系统的可持续发展摘要:城市化和机动化的快速增长,通常有助于城市交通系统的发展，是经济性，环境性和社会可持续性的体现,但其结果是交通量无情增加，导致交通拥挤。
道路拥挤定价已经提出了很多次，作为一个经济措施缓解城市交通拥挤，但还没有见过在实践中广泛使用，因为道路收费的一些潜在的影响仍然不明。
本文首先回顾可持续运输系统的概念,它应该满足集体经济发展,环境保护和社会正义的目标.然后,根据可持续交通系统的特点，使拥挤收费能够促进经济增长，环境保护和社会正义。
研究结果表明,交通拥堵收费是一个切实有效的方式，可以促进城市交通系统的可持续发展。
一、介绍城市交通是一个在世界各地的大城市迫切关注的话题。
随着中国的城市化和机动化的快速发展,交通拥堵已成为一个越来越严重的问题,造成较大的时间延迟,增加能源消耗和空气污染，减少了道路网络的可靠性．在许多城市,交通挤塞情况被看作是经济发展的障碍.我们可以使用多种方法来解决交通挤塞,包括新的基础设施建设，改善基础设施的维护和操作,并利用现有的基础设施,通过需求管理策略,包括定价机制,更有效地减少运输密度.交通拥堵收费在很久以前就已提出，作为一种有效的措施,来缓解的交通挤塞情况。
交通拥堵收费的原则与目标是通过对选择在高峰拥挤时段的设施的使用实施附加收费,以纾缓拥堵情况．转移非高峰期一些出行路线,远离拥挤的设施或高占用车辆，或完全阻止一些出行,交通拥堵收费计划将在节省时间和降低经营成本的基础上,改善空气中的质量，减少能源消耗和改善过境生产力。
此计划在世界很多国家和地方都有成功的应用。
继在2０世纪70年代初和8０年代中期挪威与新加坡实行收费环,在20０３年2月伦敦金融城推出了面积收费；直至现在,它都是已经开始实施拥挤收费的大都市圈中一个最知名的例子。
然而,交通拥堵收费由于理论和政治的原因未能在实践中广泛使用。
道路收费的一些潜在的影响尚不清楚,和城市发展的拥塞定价可持续性,需要进一步研究。
外文文献翻译译稿和原文
外文文献翻译译稿1卡尔曼滤波的一个典型实例是从一组有限的，包含噪声的，通过对物体位置的观察序列（可能有偏差）预测出物体的位置的坐标及速度。
在很多工程应用（如雷达、计算机视觉）中都可以找到它的身影。
同时，卡尔曼滤波也是控制理论以及控制系统工程中的一个重要课题。
例如，对于雷达来说，人们感兴趣的是其能够跟踪目标。
但目标的位置、速度、加速度的测量值往往在任何时候都有噪声。
卡尔曼滤波利用目标的动态信息，设法去掉噪声的影响，得到一个关于目标位置的好的估计。
这个估计可以是对当前目标位置的估计（滤波），也可以是对于将来位置的估计（预测），也可以是对过去位置的估计（插值或平滑）。
命名[编辑]这种滤波方法以它的发明者鲁道夫.E.卡尔曼（Rudolph E. Kalman）命名，但是根据文献可知实际上Peter Swerling在更早之前就提出了一种类似的算法。
斯坦利。
施密特（Stanley Schmidt）首次实现了卡尔曼滤波器。
卡尔曼在NASA埃姆斯研究中心访问时，发现他的方法对于解决阿波罗计划的轨道预测很有用，后来阿波罗飞船的导航电脑便使用了这种滤波器。
关于这种滤波器的论文由Swerling（1958）、Kalman (1960)与Kalman and Bucy（1961）发表。
目前，卡尔曼滤波已经有很多不同的实现。
卡尔曼最初提出的形式现在一般称为简单卡尔曼滤波器。
除此以外，还有施密特扩展滤波器、信息滤波器以及很多Bierman, Thornton开发的平方根滤波器的变种。
也许最常见的卡尔曼滤波器是锁相环，它在收音机、计算机和几乎任何视频或通讯设备中广泛存在。
以下的讨论需要线性代数以及概率论的一般知识。
卡尔曼滤波建立在线性代数和隐马尔可夫模型（hidden Markov model）上。
其基本动态系统可以用一个马尔可夫链表示，该马尔可夫链建立在一个被高斯噪声（即正态分布的噪声）干扰的线性算子上的。
系统的状态可以用一个元素为实数的向量表示。
大观茶论原文及翻译
大观茶论原文及翻译大观茶论是唐代陆羽所著的一本茶叶研究论文，全文共12卷，详细阐述了茶的起源、分类、栽培、制作、品饮等方面的知识。
这部著作具有划时代的意义，被誉为中国茶文化的经典之作。
以下是《大观茶论》开篇的部分内容：茶，一名扶摇子，自鸡公山逐雁荡，继有关仓、杨子两草庐之术。
乃至孙叔向之园，孙文。
至如卓氏郦山园观自昆明后进矣。
东方微雨露，稍菁悴；太湖燕子舌，稍粗大。
百年之间，数易其土，而人民俗好之诚坚不化（为社稷尧舜之化咎）。
何者？类多而变近，惟进不敢治制也。
茶之头义，惟云三五。
抑韵之言，无解。
于禅肇，诚对如邻。
然则良思良词以在兹舌之蛇者，何为五世？如言如来，祖于殿上朝天。
穆穆尧舜，“黔露充雪”，向阳; “南山之阳，至比为悲，崇崖峻壁，春风烟雨。
无时不有”的文同。
“向应春风，知见之地，群像略不加震，春露韵音”。
造船起自东南，歧十朝事；尼效山水矣。
东阳令则改南朝半斤之域，前后皆可称一工，则物产略有不同矣。
以下为《大观茶论》开篇内容的简单翻译：The "Treatise on Tea" is a research paper on tea written by Lu Yu during the Tang Dynasty. It consists of 12 volumes, providing detailed information on the origin, classification, cultivation, processing, and consumption of tea. This work is considered a milestone in the development of Chinese tea culture.Here is a part of the opening passage of "Treatise on Tea":Tea, named "Fu Yao Zi," originated from the Ji Gong Mountain chasing the Wild Goose Pond. It then acquired the knowledge of the Guan Cang and Yang Zi grass huts. Following that, Sun Shuoxiang's garden and Sun Wen continued the tradition. Later on, Zhuo Shi Li Shan Yuan from Kunming made further contributions. Tea leaves from the eastern regions are delicate due to the gentle rain and dew, while those from Taihu Lake have thicker and larger leaves. Over the span of ahundred years, the land has changed multiple times, but the people's love for tea has remained steadfast (as a virtue inherited from the sage kings Yao and Shun). Why is this so? There is great variety among the tea species that grow closer together, making progress while avoiding excessive regulation.The essence of tea is elusive, only described as "threeor five." Its significance in rhyme cannot be easily explained. It profoundly relates to the Zen initiators like neighboring companions. Therefore, the wise thoughts andwords are like the tongue of a snake, crawling with the question of five generations and the words of Tathagata, who originated in the Palace, with his back to the sky. The dignified Yao and Shun's poems were filled with "black dew covering snow" and the sunlight; with "the sunny side of Nanshan, compared to sadness, towering cliffs, spring breeze, and rain. There is no time without" such harmonious words.The making of boats started from the southeast and lasted ten dynasties; Buddhist priests emulate the mountains and rivers.The Dongyang magistrate altered the half-jin territory of the Southern Dynasty and both before and after, it can be regarded as a single craftsmanship, resulting in slightly different products.This is a simple translation of the opening passage of "Treatise on Tea."。
《典论·论文》全文、注释、翻译和赏析
《典论·论文》全文、注释、翻译和赏析曹丕文人相轻，自古而然。
傅毅之于班固(1)，伯仲之间耳(2); 而固小之(3)，与弟超书曰(4)：“武仲以能属文，为兰台令史(5)，下笔不能自休(6)。
”夫人善于自见，而文非一体，鲜能备善(7)。
是以各以所长，相轻所短。
里语(8)曰：“家有弊帚，享之千金(9)。
”斯不自见之患也。
今之文人，鲁国孔融文举(10)、广陵陈琳孔璋(11)、山阳王粲仲宣(12)、北海徐干伟长(13)、陈留阮瑀元瑜(14)、汝南应玚德琏(15)、东平刘桢公干(16)，斯七子者(17)，于学无所遗，于辞无所假(18)，咸以自骋骥騄于千里，仰齐足而并驰(19)。
以此相服，亦良难矣(20)。
盖君子审己以度人，故能免于斯累，而作《论文》(21)。
王粲长于辞赋，徐干时有齐气，然粲之匹也(22)。
如粲之《初征》、《登楼》、《槐赋》、《征思》，干之《玄猿》、《漏巵》、《圆扇》、《橘赋》(23)，虽张、蔡不过也(24)。
然于他文，未能称是(25)。
琳、瑀之章表书记，今之隽也(26)。
应玚和而不壮(27)。
刘桢壮而不密(28)。
孔融体气高妙，有过人者; 然不能持论，理不胜辞，以至乎杂以嘲戏(29)。
及其所善，扬、班俦也(30)。
常人贵远贱近，向声背实，又患闇于自见(31)，谓己为贤。
夫文，本同而末异(32)。
盖奏议宜雅，书论宜理，铭诔尚实，诗赋欲丽(33)。
此四科不同，故能之者偏也(34);唯通才能备其体(35)。
文以气为主，气之清浊有体，不可力强而致(36)。
譬诸音乐。
曲度虽均，节奏同检(37)，至于引气不齐(38)，巧拙有素(39)，虽在父兄，不能以移子弟(40)。
盖文章，经国之大业(41)，不朽之盛事。
年寿有时而尽，荣乐止乎其身(42)。
二者必至之常期(43)，未若文章之无穷。
是以古之作者，寄身于翰墨(44)，见意于篇籍(45)，不假良史之辞，不托飞驰之势，而声名自传于后(46)。
故西伯幽而演《易》(47)，周旦显而制《礼》(48)，不以隐约而弗务(49)，不以康乐而加思(50)。
初一文言文《论文十则》原文及翻译
初一文言文《论文十则》原文及翻译1、子曰：“学而时习之，不亦说乎?有朋自远方来，不亦乐乎?人不知而不悦，不亦君子乎?”(《学而》)学习需要不断复习才能掌握。
学了知识，按时复习，这是愉快的事。
这里既有学习方法，也有学习态度。
朋，这里指志同道合的人。
有志同道合的人从远方来，在一起探讨问题，是一种乐趣。
人家不了解，我却不怨恨，是君子的风格。
这是讲个人修养问题。
2、子曰：“温故而知新，可以为师矣。
”(《为政》)复习旧的知识，能够从中有新的体会或发现。
这样，就可以做老师了。
3、子曰：“学而不思则闰；思而不学则殆。
”(《为政》)只读书而不肯动脑筋思考，就会感到迷惑；只是一味空想而不肯读书，就会有疑惑。
这里阐述了学习和思考的辩证关系，也是讲学习方法的。
4、子曰：“由，诲女知之乎!知之为知之，不知为不知，是知也。
”(《为政》)孔于说：“子路，教给你正确认识事物的道理吧。
(那就是)知道就是知道，不知道就是不知道，这就是聪明智慧。
”这段说的是对待事物的正确态度。
5、子贡问曰：“孔文子何以谓之‘文’也?”子曰：“敏而好学，不耻下问，是以谓之‘文’也。
”(《公冶长》)子贡问道：“孔文子为什么叫“文”呢?”孔子说：“他聪敏而又爱好学刁，并且不以向不如自己的人请教为耻。
因此用‘文’做他的谥号。
”这里借回答于贡的`问话，借题发挥，教育弟子要勤学好问。
6、子曰：“默而识之，学而不厌，诲人不倦，何有于我哉!”(《述而》)这一则是孔子的自述，讲的是学习态度和方法。
要把学过的东西默默地记在心里，不断积累知识。
“学而不厌”，讲的是好学精神，学无止境，从不感到满足。
“诲人不倦”，讲的是教学态度，要热情地教导学生。
孔于一生都是这样做的，所以他说：“对我来说，有什么呀?”表现了孔子的自信。
7、子曰：“三人行，必有我师焉；择其善者而从之，其不善者而改之。
”(《述而》)孔子说：“几个人在一起走路，其中一定有人可以当我的老师。
应当选择他们的优点去学习，对他们的缺点，要注意改正。
袁宗道《论文》原文及翻译译文
袁宗道《论文》原文及翻译译文1、袁宗道《论文》原文及翻译译文袁宗道《论文》原文及翻译袁宗道原文：口舌，代心者也;文章，又代口舌者也。
展转隔碍，虽写得畅显，已恐不如口舌矣，况能如心之所存乎?故孔子论文曰：“辞达而已。
”达不达，文不文之辨也。
唐、虞、三代之文，无不达者。
今人读古书，不即通晓，辄谓古文奇奥，今人下笔不宜平易。
夫时有古今，语言亦有古今，今人所诧谓奇字奥句，安知非古之街谈巷语耶?左氏去古不远，然《传》中字句，未尝肖《书》也。
司马去左亦不远，然《史记》句字，亦未尝肖左也。
至于今日，逆数前汉，不知几千年远矣。
自司马不能同于左氏，而今日乃欲兼同左、马，不亦谬乎?中间历晋、唐，经宋、元，文士非乏，未有公然挦扯古文，奄为己有者。
昌黎好奇偶一为之如《毛颖》等传一时戏剧他文不然也。
空同①不知，篇篇模拟，亦谓“反正②”。
后之文人，遂视为定例，尊若令甲③。
凡有一语不肖古者，即大怒，骂为“野路恶道”。
不知空同模拟，自一人创之，犹不甚可厌。
迨其后一传百，以讹益讹，愈趋愈下，不足观矣。
且空同诸文，尚多己意，纪事述情，往往逼真，其尤可取者，地名官衔，俱用时制。
今却嫌时制不文，取秦汉名衔以文之，观者若不检《一统志》④，几不识为何乡贯矣。
且文之佳恶，不在地名官衔也，史迁之文，其佳处在叙事如画，议论超越;而近说乃云，西京⑤以还，封建宫殿，官师郡邑，其名不雅驯，虽史迁复出，不能成史。
则史迁佳处，彼尚未梦见也，而况能肖史迁也乎?或曰：信如子言，古不必学耶?余曰：古文贵达，学达即所谓学古也。
学其意，不必泥其字句也。
今之圆领方袍，所以学古人之缀叶蔽皮也;今之五味煎熬，所以学古人之茹毛饮血也。
何也?古人之意，期于饱口腹，蔽形体;今人之意，亦期于饱口腹，蔽形体，未尝异也。
彼摘古字句入己著，是无异缀皮叶于衣袂之中，投毛血于肴核之内也。
大抵古人之文，专期于达，而今人之文，专期于不达。
以不达学达，是可谓学古者乎?(取材于袁宗道《论文》)【注】①空同：李梦阳，号空同子，明代文学家。
英语议论文经典范文3篇（带翻译）
英语议论文经典范文3篇（带翻译）英语议论文经典范文3篇（带翻译）有很多的同学在写英语作文的时候，也会写一些经典的议论文，小编整理了相关范文，希望会对大家有所帮助！英语作文范文带中文翻译Manyyearsago,themovieabouttheyouthbecameverypopular, everyyear,wecanseeman yhotmoviesabouttheprotagonist’spassedyouth.Peopleliketorec alltheirpassedyouth, whichmakessuchmoviessellgood.ButIfindthecommonthingsabo utthesemovies,alltheprotagonists’youthareaboutfighting,loveandothernegativethin gs.Iunderstandthedirectors’intention,they wanttotellpeopleyouthisnotperfectandhav ingpities.Ofcoursemovieisexaggerating,therealyouthisaboutstudying,atleast,mostp eoplehaveworkedsohardtogetintotheiridealcolleges.Whatthemoviesdescribemakeup somepeople’syouth,forwhichtheydon’thavethechancetoexperienc e.Weshouldnot bemisledbythesemovies,fortheteenagers,theirjobistostudy,sothattheycanhaveabright future.【翻译】很多年以前，关于青春的电影很受欢迎，此后每年，我们都可以看到很多热门电影是关于主人公逝去的青春。
典论·论文翻译
典论·论文翻译Company number：【0089WT-8898YT-W8CCB-BUUT-202108】典论·论文（原文）曹丕文人相轻，自古而然。
傅毅之于班固，伯仲之间耳，而固小之，与弟超书曰：“武仲以能属文为兰台令史，下笔不能自休。
”夫人善于自见，而文非一体，鲜能备善，是以各以所长，相轻所短。
里语曰：“家有弊帚，享之千金。
”斯不自见之患也。
今之文人：鲁国孔融文举、广陵陈琳孔璋、山阳王粲仲宣、北海徐干伟长、陈留阮瑀元瑜、汝南应瑒（yáng）德琏（lin）、东平刘桢公干，斯七子者，于学无所遗，于辞无所假，咸自以骋骥騄于千里，仰齐足而并驰。
以此相服，亦良难矣！盖君子审己以度人，故能免于斯累，而作《论文》。
王粲长于辞赋，徐干时有齐气，然粲之匹也。
如粲之《初征》、《登楼》、《槐赋》、《征思》，干之《玄猿》、《漏卮》、《圆扇》、《橘赋》，虽张、蔡不过也，然于他文未能称是。
琳、瑀之章表书记，今之隽也。
应瑒和而不壮；刘桢壮而不密。
孔融体气高妙，有过人者；然不能持论，理不胜辞；至于杂以嘲戏；及其所善，扬、班俦也。
常人贵远贱近，向声背实，又患闇（àn）于自见，谓己为贤。
夫文本同而末异，盖奏议宜雅，书论宜理，铭诔尚实，诗赋欲丽。
此四科不同，故能之者偏也；唯通才能备其体。
文以气为主，气之清浊有体，不可力强而致。
譬诸音乐，曲度虽均，节奏同检，至于引气不齐，巧拙有素，虽在父兄，不能以移子弟。
盖文章，经国之大业，不朽之盛事。
年寿有时而尽，荣乐止乎其身，二者必至之常期，未若文章之无穷。
是以古之作者，寄身于翰墨，见意于篇籍，不假良史之辞，不托飞驰之势，而声名自传于后。
故西伯幽而演《易》，周旦显而制《礼》，不以隐约而弗务，不以康乐而加思。
夫然，则古人贱尺璧而重寸阴，惧乎时之过已。
而人多不强力；贫贱则慑于饥寒，富贵则流于逸乐，遂营目前之务，而遗千载之功。
日月逝于上，体貌衰于下，忽然与万物迁化，斯志士之大痛也！融等已逝，唯干着论，成一家言。
机械类英语论文及翻译
Mechanical DesignAbstract:A machine is a combination of mechanisms and other components which transforms, transmits. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines. The term "mechanical design" is used in a broader sense than "machine design" to include their design. the motion and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical devices, such as switches, cams, valves, vessels, and mixers.Keywords: Mechanical Design ；Rules for Design ；Design ProcessThe Design ProcessDesigning starts with a need real.Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previously done by men, such as computation, assembly, or servicing. With the objective wholly or partly.In the design preliminary stage, should allow to design the personnel fullyto display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts.When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strengths of the several components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles of mechanics, such as those of static for reaction forces and for the optimum utilization of friction; of dynamics for inertia, acceleration, and energy; of elasticity and strength of materials for stress and deflection; of physical behavior of materials; and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrangement of mechanisms, or, in a large company, they may be made by a separate analysis division or research group. Design is a reiterative and cooperative process, whetherdone formally or informally, and the analyst can contribute to phases other than his own. Product design requires much research and development. Many Concepts of an idea must be studied, tried, and then either used or discarded. Although the content of each engineering problem is unique, the designers follow the similar process to solve the problems.Product liability suits designers and forced in material selection, using the best program. In the process of material, the most common problems for five (a) don't understand or not use about the latest application materials to the best information, (b) failed to foresee and consider the reasonable use material may (such as possible, designers should further forecast and consider due to improper use products. In recent years, many products liability in litigation, the use of products and hurt the plaintiff accused manufacturer, and won the decision), (c) of the materials used all or some of the data, data, especially when the uncertainty long-term performance data is so, (d) quality control method is not suitable and unproven, (e) by some completely incompetent persons choose materials.Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to thesuitable procedure, may greatly reduce the lawsuit the quantity.May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding.Finally, a design based upon function, and a prototype may be built. If its tests are satisfactory, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicate alterations. Sales appeal.Some Rules for DesignIn this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfection of alternate, perhaps more functional, economical,and durable products.To stimulate creative thought, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst.1. A creative use of need of physical properties and control process.2. Recognize functional loads and their significance.3. Anticipate unintentional loads.4. Devise more favorable loading conditions.5. Provide for favorable stress distribution and stiffness with minimum weight.6. Use basic equations to proportion and optimize dimensions.7. Choose materials for a combination of properties.8. Select carefully, stock and integral components.9. Modify a functional design to fit the manufacturing process and reduce cost.10. Provide for accurate location and noninterference of parts in assembly.Machinery design covers the following contents.1. Provides an introduction to the design process , problem formulation ,safety factors.2. Reviews the material properties and static and dynamic loading analysis ,Including beam , vibration and impact loading.3. Reviews the fundamentals of stress and defection analysis.4. Introduces fatigue-failure theory with the emphasis on stress-life approaches to high-cycle fatigue design, which is commonly used in the design of rotation machinery.5. Discusses thoroughly the phenomena of wear mechanisms, surface contact stresses ,and surface fatigue.6. Investigates shaft design using the fatigue-analysis techniques.7. Discusses fluid-film and rolling-element bearing theory and application8. Gives a thorough introduction to the kinematics, design and stress analysis of spur gears , and a simple introduction to helical ,bevel ,and worm gearing.9. Discusses spring design including compression ,extension and torsion springs.10. Deals with screws and fasteners including power screw and preload fasteners.11. Introduces the design and specification of disk and drum clutches and brakes.Machine DesignThe complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge.One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to today's designers. The function of the product, its appearance, the cost of thematerial, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations.Careful calculations are necessary to ensure the validity of a design. In case of any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should be checked and rechecked.The computer is a tool helpful to mechanical designers to lighten tedious calculations, and provide extended analysis of available data. Interactive systems, based on computer capabilities, have made possible the concepts of computer aided design (CAD) and computer-aided manufacturing (CAM). How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnel''s basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved.This generally is through the oral discussion, the schematic diagram and the writing material carries on.If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of productMust regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly.A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, because spends the time and the endeavor certainlycannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea.外文论文翻译译文机械设计摘要：机器是由机械装置和其它组件组成的。
毕业论文英语翻译及原文
=H（ - ）（1）
respectively, the expression can be easily gained as follows
Then, the relation equation between the two baseline vectors is expressedas
There are two steps in the GPS observation data processing course. They are baseline calculationand network adjustment. The baseline vectors in WGS-84 can be firstly got using baseline calculation.Secondly, the baseline vector transformation from WGS-84 to the station orthogonal coordinatesystem can be done with (3). At last, the adjustment of GPS deformatihestation orthogonal coordinate system can be successfully finished.
If the position vector of the station orthogonal coordinate system originP0inWGS-84 isexpressed as = , according to thegeodetic latitude and longitude（ ， ）, theposition vector
论文外文文献翻译
论文外文文献翻译以下是一篇700字左右的论文外文文献翻译：原文题目：The Role of Artificial Intelligence in Medical Diagnostics: A Review原文摘要：In recent years, there has been a growing interest in the use of artificial intelligence (AI) in the field of medical diagnostics. AI has the potential to improve the accuracy and efficiency of medical diagnoses, and can assist clinicians in making treatment decisions. This review aims to examine the current state of AI in medical diagnostics, and discuss its advantages and limitations. Several AI techniques, including machine learning, deep learning, and natural language processing, are discussed. The review also examines the ethical and legal considerations associated with the use of AI in medical diagnostics. Overall, AI has shown great promise in improving medical diagnostics, but further research is needed to fully understand its potential benefits and limitations.AI在医学诊断中发挥的作用：一项综述近年来，人工智能（AI）在医学诊断领域的应用引起了越来越多的关注。
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。
大学诚意篇原文及翻译
大学诚意篇原文及翻译原文：所谓诚其意者，毋自欺也。
如恶恶臭，如好好色。
此之谓自谦。
故君子必慎其独也。
小人闲居为不善，无所不至。
见君子而后厌然，掩其不善，而著其善。
人之视己，如见其肺肝然，则何益矣？此谓诚於中，形於外。
故君子必慎其独也。
曾子曰：“十目所视，十手所指，其严乎！”富润屋，德润身，心广体胖，故君子必诚其意。
译者：所谓使自己的意念诚实，就是说不要自欺。
要像憎恶腐臭的气味一样，要像爱好美好的容貌一样，这就是说自己不亏心。
因此，君子对独居这事必须谨慎。
小人独居，干不好的事，没有什么做不出来的；看见了君子，这才躲躲藏藏地把不好的掩盖起来，把好的显示出来。
其实人们看他，正像看透他里面的肺肝一样，躲藏掩盖又有什么益处呢？这就是说，里面有什么样的实在东西，外面就必然会有什么样的表现。
所以君子必须在独居时很谨慎。
有关写作：读《礼记》应该把注意力集中在正文和郑注上。
不要喧宾夺主，就是说，不要忽视正文、抛开郑注而花很大精力去看其它的注解书籍。
念《礼记》必须把四十九文字分为几大类回去念。
章性质相似，资料范围相同，就更容易索解。
念《礼记》必须实行先易后难的办法。
按前面粗略的分类来说，可以上节那些文字比较畅通的论文，例如《礼运》、《学记》等；其次念有关孔子言论的，例如《坊记》、《念法》等；其次念表明《仪礼》的，例如《冠义》、《昏义》等；其次念记载各种礼制的，例如《礼器》、《郊特牲》等；其次念记述生活日常礼节的，例如《曲礼》、《内则》、《太少仪》等；最后念那一批有关后事朝服的。
读《礼记》要孤立难点。
比如每读一，凡看不懂的正文、郑注，或对郑的注解有所怀疑的地方，都一一标出。
等读完一后，回过头来，再看《礼记正义》或其他注解书。
《礼记》文字比《易经》、《尚书》、《仪礼》好懂些，每通过郑注仍看不懂的`地方，一般说来不会很多。
把一些难词难句集中起来，用有关注解书、工具书解决，这是比较省力省时的办法。
五十几年前，梁启超在《要籍解题及其读法》一书中，对念《礼记》必须特别注意些什么，明确提出了很存有指导意义的意见。
问说原文及翻译
《问说》是清代刘开写的一篇议论文。
“说”是一种文体，通过发表议论或记述事物来说明某个道理。
本文的中心论点为“君子之学必好问”，叙述了“问”在学习的过程中的重要作用。
所谓“学问”，就是“学”与“问”的结合，“学”与“问”相铺相成，缺一不可。
原文必好问（1）。
问与学，相辅而行者也。
非学无以致疑（2），非问无以广识（3）；好学而不勤问，非真能好学者也。
理明矣，而或不达（4）于事；识其大矣，而或不知其细，舍问，其奚决焉？（5）贤于己者，问焉以破其疑，所谓“就而正”（6）也。
不如己者，问焉以求，所谓“以能问于不能，以多问于寡”也。
等于己者，问焉以资切磋（7），所谓交相问难(nàn)（8），审（9）问而明辨之也。
《书》不云乎？“好问则裕。
”孟子论“求放心”，而并称曰“学问之道”，学即继以问也。
子思言“尊”，而归于“道问学”，问且先于学也。
古之人，不择事而问焉，不择人而问焉，取其有益于身而已。
是故狂夫之言，圣人择之，(ráo)之微，先民询之，舜以天子而询于匹夫，以大知而察及迩言，非苟为谦，诚取善之弘也。
三代而下，有学而无问，朋友之交，至于足矣，其以相咨访，孜孜焉唯进修是急，未之多见也，况流俗乎？是己而非人（10），俗之同病。
学有未达，强(qiǎng)以为知；理有未安（11），妄以臆度(duó)。
如是，则终身几无可问之事。
贤于己者，忌之而不愿问焉；不如己者，轻之而不屑问焉；等于己者，狎（xiá）（12）之而不甘问焉，如是，则天下几无可问之人。
人不足服矣，事无可疑矣，此唯师心自用耳。
夫自用，其小者也；自知其陋而谨护其失，宁使学终不进，不欲虚以下人，此为害于者大，而蹈之者常十之八九。
不然，则所问非所学焉：询天下之；甚且心之所已明者，问之人以试其能，事之至难解者，问之人以穷其短。
而非是者，虽有切于身心性命之事，可以收取善之益，求一屈己焉而不可得也。
嗟乎！学之所以不能几(jī)于古者，非此之由乎？且夫不好问者，由心不能虚也；心之不虚，由好学之不诚也。
本科毕业设计(论文)外文翻译译文
本科毕业设计（论文）外文翻译译文学生姓名：院（系）：油气资源学院专业班级：物探0502指导教师：完成日期：年月日地震驱动评价与发展：以玻利维亚冲积盆地的研究为例起止页码：1099——1108出版日期：NOVEMBER 2005THE LEADING EDGE出版单位：PanYAmericanYEnergyvBuenosYAiresvYArgentinaJPYBLANGYvYBPYExplorationvYHoustonvYUSAJ.C.YCORDOVAandYE.YMARTINEZvYChacoYS.A.vYSantaYCruzvYBolivia 通过整合多种地球物理地质技术，在玻利维亚冲积盆地，我们可以减少许多与白垩纪储集层勘探有关的地质技术风险。
通过对这些远景区进行成功钻探我们可以验证我们的解释。
这些方法包括盆地模拟，联井及地震叠前同时反演，岩石性质及地震属性解释，A VO/A V A,水平地震同相轴，光谱分解。
联合解释能够得到构造和沉积模式的微笑校正。
迄今为止，在新区有七口井已经进行了成功钻探。
基质和区域地质。
Tarija/Chaco盆地的subandean 褶皱和冲断带山麓的中部和南部，部分扩展到玻利维亚的Boomerange地区经历了集中的成功的开采。
许多深大的泥盆纪气田已经被发现，目前正在生产。
另外在山麓发现的规模较小较浅的天然气和凝析气田和大的油田进行价格竞争，如果他们能产出较快的油流而且成本低。
最近发现气田就是这种情况。
接下来，我们赋予Aguja的虚假名字就是为了讲述这些油田的成功例子。
图1 Aguja油田位于玻利维亚中部Chaco盆地的西北角。
基底构造图显示了Isarzama背斜的相对位置。
地层柱状图显示了主要的储集层和源岩。
该油田在Trija和冲积盆地附近的益背斜基底上，该背斜将油田和Ben i盆地分开（图1），圈闭类型是上盘背斜，它存在于连续冲断层上，Aguja有两个主要结构：Aguja中部和Aguja Norte,通过重要的转换压缩断层将较早开发的“Sur”油田分开Yantata Centro结构是一个三路闭合对低角度逆冲断层并伴随有小的摆幅。
20外文文献翻译原文及译文参考样式
20外⽂⽂献翻译原⽂及译⽂参考样式华北电⼒⼤学科技学院毕业设计（论⽂）附件外⽂⽂献翻译学号： 0819******** 姓名：宗鹏程所在系别：机械⼯程及⾃动化专业班级：机械08K1指导教师：张超原⽂标题：Development of a High-PerformanceMagnetic Gear年⽉⽇⾼性能磁齿轮的发展1摘要：本⽂提出了⼀个⾼性能永磁齿轮的计算和测量结果。
上述分析的永磁齿轮有5.5的传动⽐，并能够提供27 Nm的⼒矩。
分析表明，由于它的弹簧扭转常数很⼩，因此需要特别重视安装了这种⾼性能永磁齿轮的系统。
上述分析的齿轮也已经被应⽤在实际中，以验证、预测其效率。
经测量，由于较⼤端齿轮传动引起的磁⼒齿轮的扭矩只有16 Nm。
⼀项关于磁齿轮效率损失的系统研究也展⽰了为什么实际⼯作效率只有81％。
⼀⼤部分磁损耗起源于轴承，因为机械故障的存在，此轴承的备⽤轴承在此时是必要的。
如果没有源于轴的少量磁泄漏，我们估计能得到⾼达96％的效率。
与传统的机械齿轮的⽐较表明，磁性齿轮具有更好的效率和单位体积较⼤扭矩。
最后，可以得出结论，本⽂的研究结果可能有助于促进传统机械齿轮向磁性齿轮发展。
关键词：有限元分析（FEA）、变速箱，⾼转矩密度，磁性齿轮。
⼀、导⾔由于永久磁铁能产⽣磁通和磁⼒，虽然⼏个世纪过去了，许多⼈仍然着迷于永久磁铁。
，在过去20年的复兴阶段，正是这些优点已经使得永久磁铁在很多实际中⼴泛的应⽤，包括在起重机，扬声器，接头领域，尤其是在永久磁铁电机⽅⾯。
其中对永磁铁的复兴最常见于效率和转矩密度由于永磁铁的应⽤显著提⾼的⼩型机器的领域。
在永久磁铁没有获取⾼度重视的⼀个领域是传动装置的领域，也就是说，磁⼒联轴器不被⼴泛⽤于传动装置。
磁性联轴器基本上可以被视为以传动⽐为1：1磁⼒齿轮。
相⽐标准电⽓机器有约10kN m/m的扭矩，装有⾼能量永久磁铁的磁耦有⾮常⾼的单位体积密度的扭矩，变化范围⼤约300–400 kN 。
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非惯性系中标量场和狄拉克场的非最大纠缠衰减潘启元荆继良中华人民共和国湖南 410081 长沙湖南师范大学教育部低维量子结构与调控重点实验室物理系物理研究所（2007 年7月18日接收；2008年2月18日发行）我们研究了两个相对加速的观测者所观察的自由标量场与狄拉克场两种形式之间的纠缠。
我们发现，受Unruh效应的影响，初始态参数α与其“归一化伙伴”两者的同一初始纠缠态将会沿着两条不同的轨道衰减，这里排除了体现闵科夫斯基和Rindler坐标系下自由场的不对等量化的最大纠缠态。
在无穷大加速度极限下，标量场中对于任意α的态没有可提纯的纠缠，但是对于狄拉克场总有依赖α的纠缠度。
有趣的是在加速度极限下互信息只有初始互信息的一半；这一结果与α和场的形式无关。
DOI: 10.1103/PhysRevA.77.024302 PACS number(s): 03.65.Ud, 04.62.+v, 04.70.D近年来量子信息理论取得了迅速的进展。
并且越来越多的工作已推广到相对论框架下去进行研究。
相对论背景下的纠缠已经得到了相当一部分人的注意，因为纠缠可作为主要的资源应用于很多量子信息操作中，如量子远程通信、量子计算等。
除了量子信息的潜在利益外，对量子纠缠的研究也能深化我们对黑洞热力学和黑洞信息疑难的理解。
因此，许多专家对不同场相对论框架下的量子纠缠进行了研究。
近期，Fuentes-Schuller and Alsing证实了纠缠取决于相对加速的观察者中的一个观察者在加速前的相对加速度的大小，而这两观察者共享一个最大的纠缠的玻色子或费米子对。
他们的结果也表明：不同类型的场对由Unruh效应产生的纠缠衰减在本质上有不同的影响。
在这简短的报告中，我们选取一个一般纠缠态作为初始纠缠态：α满足|α|∈(0,1)，α和互为“归一化伙伴”。
由于初始态参数α的存在，我们将试图观察对于两个相对加速的观察者这个不确定的初始纠缠态将会对纠缠的衰减产生怎样的影响。
我们需要注意，施瓦兹时空与无穷大加速度极限下的Rindler空间相类似。
因此，我们在这个极限下的研究结果可以用来讨论两个玻色子或是费米子模式间的纠缠，当一个观察者掉入黑洞，另外一个刚好以恒定的加速度逃逸时，这一纠缠可以被观测到。
Rindler坐标系适合于描述均匀加速运动的观察者。
在闵科夫斯基时空作均匀加速运动的观察者的世界线与原点左边（区域I）和右边（区域II）的双曲线相对应，该双曲线被限制在构成Rindler视界的类光渐近线内，因此两个Rindler区域相互之间理所当然的没有联系。
一个均匀加速的观察者被限制在Rindler区域I或区域II并且不能进入到另一个区域。
从惯性系来看方程（1）所描述的系统是双向的，但在非惯性系，区域II的一组额外的模变得相关。
因此我们将研究惯性系中的观察者Alice检测的模s态和以加速度a均匀加速的观察者Bob检测的模k态之间的纠缠混态。
玻色子纠缠。
对于自由标量场，闵科夫斯基真空态可用Rindler时空中的双模压缩态来描述，，k是波矢，r是加速度参量，和分别是Rindler区域I的粒子模和Rindler区域II的反粒子模。
运用方程(2)和第一激发态我们可以按照Alice使用闵科夫斯基模和Bob使用Rindler模来改写方程(1)，既然Bob与区域II因果不相连，我们写出这个区域的态从而得到。
部分转置标准为例[11]中纠缠的存在提供了充分的条件：部分转置图1.(彩色线)不同α的玻色子模的对数负度随加速度r的变化图。
矩阵至少存在一个负的本征值，密度矩阵才是纠缠的；但正转置矩阵的态仍然是纠缠的。
这是我们熟知的束缚纠缠态或是不可提纯的纠缠态。
通过交换Alice的量子比特，我们得到(n,n+1)范围内转置矩阵的本征值。
很明显在加速度有限的情况下()本征值总是负值。
因此，该混态对于Bob的任何有限加速度总是纠缠态。
在的极限下，负的本征值将会趋近于零。
进一步讨论，我们采用作为可提纯纠缠上界的对数负度。
此单调纠缠度定义为，是部分转置矩阵的矩阵迹范数。
所以我们得到对于零加速度()，。
在范围内，α越大，初始纠缠就越强；但在范围内，α越大，初始纠缠就越弱。
对于有限的加速度，α不同，随着r的增加而单调减少，这表明初始态纠缠度不受Unruh效应产生的热场的影响。
从图1我们惊奇地发现除了最大纠缠态外(|)，具有参数α和它的“归一化伙伴”的同一初始纠缠将沿着两条不同的的轨迹衰减。
这一现象是因α与关于r的双曲函数的关联而产生的，并表明对于闵科夫斯基坐标和Rindler坐标下的标量场的不对等量化。
在的极限下对于任一α对数负度都等于零，图2.(彩色线)不同α的玻色子模的互信息随加速度r的变化图。
这表明该态不存在可提纯纠缠。
互信息可以用来估计系统的任何两个子系统之间的关联程度，定义为：这里是密度矩阵的熵。
从方程(3)，我们可以得到该关联态的熵，对对Minkowski模求迹，我们得到Bob在区域I的密度矩阵；它的熵为用同样的方法，我们通过对Rindler I区进行求迹得到Alice的密度矩阵；它的熵为在图2中我们画出了对不同的α情况下的态的互信息随r的变化曲线。
对加速度为零的情况，互信息为在的范围，α越大，互信息就越强；但在范围内，α越大，互信息就越弱。
随着加速度的增大，互信息变得越弱。
有趣的是，除了最大纠缠态，对于α和的同一初始互信息将沿着两条不同的路线衰减。
然而，在有限的加速度极限下，互信息汇合到同一个点。
图3.(彩色线)不同α的费米子模的对数负度随加速度r的变化图(注意:).该点的互信息仅为的一半。
很显然如果越大，在此极限下，它将衰减到更高的值。
既然在有限加速度极限下可提纯纠缠度为零，那么可以毫不夸张的说在此极限下总关联是由经典关联加上束缚纠缠构成。
费米子纠缠。
采用Alsing使用的单模近似，费米子闵科夫斯基真空态可写作其唯一的激发态为这里，对于加速度参数r的范围是。
对闵科夫斯基粒子态和运用方程(8)和(9)并对区域II求迹，我们得到|mn⟩=.部分转置标准给两量子比特混态纠缠提供了一个充分必要条件：如果至少有一个部分转置矩阵的本征值为负值，那么密度矩阵是纠缠的。
交换Alice的量子比特，我们得到部分转置矩阵一个本征值,对于该值总是负的。
因此，对于Bob的任一一定的加速度该态总是纠缠态。
其对数负度为图4.(彩色线)不同α的费米子模的互信息随加速度r的变化图。
对为零的加速度(r=0)，对有限的加速度，正如图3所示，受到Unruh效应的影响，纠缠度会衰减。
我们发现在的范围内，α越大，初始纠缠度越大，但这并非总是退化到更高的纠缠度。
我们应该注意到对范围的初始态的最终纠缠度比最大纠缠态的纠缠度要大，该对数负度为对于最大的最终纠缠的对数负度为在的范围内，α越大，初始纠缠越弱并且最终纠缠度越小。
对于费米场情形，除了最大纠缠态，由于α与关于r的三角函数的耦合，在加速度极限下()对于α和的同一初始费米模的纠缠将沿着两条不同路线衰减并渐进的趋于两个不同的非零最小值。
在有限的加速度极限下，这意味着该态总是纠缠的。
这与玻色场形成了鲜明的对比，同时表明费米纠缠可作为量子源在加速度无穷大极限下进行量子信息任务操作。
我们可以用同样的方法得到费米子模的互信息的初始场态的互信息随加速度r的变化轨迹如图4所示。
加速度为零时，初始互信息等于，这和玻色模的一样。
随着加速度的增加互信息变得越小，同时我们又惊奇地发现除了最大纠缠态，对于α和的同一初始互信息将沿着两条不同的路线衰减。
在有限的加速度极限下互信息汇合到同一个点仅为的一半。
这一结果使我们联想到玻色子的情形，因此我们得出该结论独立于α和场的形式。
我们应该注意到如果我们把初始纠缠态设为我们将得到图1-4同一α的纠缠度衰减的结果。
总结，非惯性系中狄拉克场和标量场的纠缠度在Unruh效应的影响下随着Bob的加速度增加而衰减，但纠缠衰减会因初始态参数α的不同而不同。
我们又惊奇地发现除了最大纠缠态，对于α和的同一初始纠缠将沿着两条不同的路线衰减，这仅表明对于闵科夫斯基和Rindler坐标系下的自由标量场的不对等的量化。
在无限的加速度极限下，可应用到Alice掉进黑洞而Bob刚好逃离黑洞的情形，该态对于标量场的任意α都没有可提纯纠缠，但对于狄拉克场总有依赖α的纠缠度。
我们应该注意到，对于,在此极限下我们将得到费米子态的最大最终纠缠。
进一步的分析表明，随着加速度参量r的增大，互信息衰减到一个非零的最小值，该值依赖于这两个场的参量α。
然而，有趣的是无穷加速度极限下的互信息刚好等于初始互信息的一半，该结果独立于α和场的形式。
本工作得到以下单位的支持，国家自然科学基金编号10675045；全国优秀博士学位论文作者专项资金资助项目编号200317；湖南省自然科学基金编号07A0128；湖南省重点学科建设项目基金。
参考文献[1] A. Peres and D. R. Terno, Rev. Mod. Phys. 76, 93 (2004); D.Boschi, S. Branca, F.De Martini, L. Hardy, and S. Popescu, Phys. Rev. Lett. 80, 1121 (1998); J. W. Pan, C. Simon, C.Brukner, and A. Zeilinger, Nature (London) 410, 1067 (2001); S. J. van Enk and T. Rudolph, Quantum Inf. Comput. 3, 423 (2003).[2] D. Bouwmeester, A. Ekert, and A. Zeilinger, The Physics of Quantum Information (Springer-Verlag, Berlin, 2000).[3] L. Bombelli, R. K. Koul, J. Lee, and R. D. Sorkin, Phys. Rev.D 34, 373 (1986); C. Callan and F. Wilzcek, Phys. Lett. B 333, 55 (1994).[4] S. W. Hawking, Commun. Math. Phys. 43, 199, 1975; Phys.Rev.D 14, 2460, (1976); H. Terashima, ibid. 61, 104016,2000.[5] A. Peres, P. F. Scudo, and D. R. Terno, Phys. Rev. Lett. 88, 230402 (2002); R. M.Gingrich and C.Adami, ibid. 89, 270402 (2002); P. M. Alsing and G. J. Milburn, ibid. 91, 180404 (2003).[6] I. Fuentes-Schuller and R. B. Mann, Phys. Rev. Lett. 95, 120404 (2005).[7] P. M. Alsing, I. Fuentes-Schuller, R. B. Mann, and T. E.Tessier, Phys. Rev. A 74, 032326 (2006).[8] P. C. W. Davies, J. Phys. A 8, 609 (1975); W. G. Unruh, Phys.Rev. D 14, 870 (1976).[9] R. M. Wald, General Relativity (University of Chicago Press,Chicago, 1984).[10] N. D. Birrell and P. C. W. Davies, Quantum Fields in CurvedSpace (Cambridge University Press, New York, 1982).[11] A. Peres, Phys. Rev. Lett. 77, 1413 (1996).[12] G. Vidal and R. F. Werner, Phys. Rev. A 65, 032314 (2002); M. B. Plenio, Phys. Rev. Lett. 95, 090503 (2005).[13] R. S. Ingarden, A. Kossakowski, and M. Ohya, Information Dynamics and Open Systems—Classical and Quantum Approach (Kluwer Academic Publishers, Dordrecht, 1997).Degradation of nonmaximal entanglement of scalar andDirac fields in noninertial framesQiyuan Pan and Jiliang Jing*Institute of Physics and Department of Physics, and Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, Hunan 410081, People’s Republic of China(Received 18 July 2007; published 8 February 2008)The entanglement between two modes of free scalar and Dirac fields as seen by two relatively accelerated observers has been investigated. It is found that the same initial entanglement for an initial state parameter αand its “normalized partner”will be degraded by the Unruh effect along two different trajectoriesexcept for the maximally entangled state, which just shows the inequivalence of the quantization for a free field in Minkowski and Rindler coordinates. In the infinite-acceleration limit, the state does not have distillable entanglement for any αfor the scalar field, but always remains entangled to a degree that is dependent on αfor the Dirac field. It is also interesting to note that in this limit the mutual information equals just half of the initial mutual information; this result is independent of αand the type of field.DOI: 10.1103/PhysRevA.77.024302 PACS number(s): 03.65.Ud, 04.62.+v, 04.70.DQuantum-information theory has made rapid progress in recent years, and more and more efforts have been expended on the study of quantum information in the relativistic framework. In particular, entanglement in a relativistic setting has received considerable attention because it is considered to be a major resource for quantum-information tasks such as quantum teleportation, quantum computation, and so on. In addition to the potential interest for quantum information, the study of entanglement can also help us get a deeper understanding of black-hole thermo dynamics and the black-hole information paradox. Thus, many authors have investigated entanglement in relativistic frames (inertial or not) for various fields.More recently, Fuentes-Schuller et al.and Alsing et al. explicitly demonstrated that entanglement is a quantity depending on the relative acceleration of one of the observers who, before being accelerated, shared a maximally entangled bosonic or fermionic pair. Their results also showed that different types of field will have qualitatively different effects on the degradation of entanglement produced by the Unruh effect.In this Brief Report, we choose a generic state as the initial entangled state:where αis some real number that satisfies , and αand are the so-called ‘‘normalized partners.’’ We will try to see what effects this uncertain initial entangled state has on the degradation of entanglement for two relatively accelerated observers due to the presence of the initial state parameter α. Notice that the Schwarzschild space-time very close to the event horizon resembles the Rindler space in the infinite-acceleration limit. Hence, as in [6,7] our results in this limit can be applied to discuss the entanglement between two free bosonic or fermionic modes seen by observers when one observer falls into a black hole and the other barely escapes through eternal uniform acceleration.Rindler coordinates are appropriate for describing the viewpoint of an observer moving with uniform acceleration. The world lines of uniformly accelerated observers in the Minkowski coordinates correspond to hyperbolas to the left (region I) and right (region II) of the origin which are bounded by lightlike asymptotes constituting the Rindler horizon [6,7],so the two Rindler regions are causally disconnected from each other [10]. An observer undergoing uniform acceleration remains constrained to either Rindler region I or II and has no access to the other sector. The system in Eq.(1) is bipartite from an inertial perspective, but in a noninertial frame an extra set of modes in region II becomes relevant. Thus, we will study the mixed-state entanglement of the state as seen by an inertial observer Alice detecting the mode s and a uniformly accelerated observer Bob with proper acceleration a in region I detecting the second mode k.Bosonic entanglement. For a free scalar field, the Minkowski vacuum state can be expressed as a two-mode squeezed state in the Rindler frame [8,10],where , k is the wave vector, r is the acceleration parameter, and and indicate the Rindler-region-I particle mode and Rindler-region-II antiparticle mode, respectively. Using Eq.(2) and the first excited state [6,10]we can rewrite Eq.(1) in terms of Minkowski modes for Alice and Rindler modes for Bob. Since Bob is causally disconnected from region II,we will trace over the states in this region and obtainFIG. 1. (Color online) Logarithmic negativity of the bosonic modes versus r for different α.where . The partial transpose criterion provides a sufficient condition for the existence of entanglement in this case [11]: if at least one eigenvalue of the partial transpose is negative, the density matrix is entangled; but a state with positive partial transpose can still be entangled. It is the well-known bound or nondistillable entanglement [12].By interchanging Alice’s qubits, we get the eigenvalues of the partial transpose in the block:where . Obviously the eigenvalue is always negative for finite acceleration (). Hence, this mixed state is always entangled for any finite acceleration of Bob. In the limit , the negative eigenvalue will go to zero. To discuss this further, we will use the logarithmic negativity which serves as an upper bound on the entanglement of distillation [12]. This entanglement monotone is defined as , where is the trace norm of the partial transpose . We therefore findFor vanishing acceleration (), . In the range the larger α, the stronger the initialentanglement; but in the range the larger α, the weaker the initial entanglement. For finite acceleration, the monotonic decrease of with increasing r for different αmeans that the entanglement of the initial state is lost to the thermal fields generated by the Unruh effect. From Fig. 1 it is surprisingly found that the same initial entanglement for αand its normalized partner will be degraded along two different trajectories except for theFIG. 2. (Color online) Mutual information of the bosonic modes versus r for different α.maximally entangled state, i.e., |This phenomenon, due to the coupling of αand the hyperbolic functions related to r, just shows the inequivalence of the quantization for a scalar field in the Minkowski and Rindler coordinates. The logarithmic negativity is exactly zero for any αin the limit , which indicates that the state does not have distillableentanglement.The mutual information, which can be used to estimate the total amount of correlations between any two subsystems of the overall system, is defined as [13]where is the entropy of the density matrix . From Eq.(3), we can obtain the entropy of this joint state,Tracing over Alice’s states for , we get Bob’s density matrix in region I; its entropy isIn the same way, we have Alice’s density matrix by tracing over Bob’s states; its entropy is given byWe draw the behaviors of the mutual information versus r for different αin Fig. 2. For vanishing acceleration, the initial mutual information is . In the range the larger α, the stronger ; but in the range the larger α, the weaker . As the acceleration increases, the mutual information becomes smaller. It is interesting to note that, except for the maximally entangled state, the same initial mu-tual information for αand will be degraded along two different trajectories. However, in the infinite-acceleration limit, the mutual information converges to the same value again, i.e.,FIG. 3. (Color online) Logarithmic negativity of the fermionic modes versus r for different α(notice that ))., which equals just half of. Obviously if is higher, it is degraded to a higher degree in this limit. Since the distillable entanglement in the infinite-acceleration limit is zero, it is safe to say that the total correlations consist of classical correlations plus bound entanglement in this limit.Fermionic entanglement. With the single-mode approximation used by Alsing et al., the fermionic Minkowski vacuum can be written as [7]and the only excited state is given bywhere and the acceleration parameter r is in the range in this case. Using Eqs.(8) and (9) for the Minkowski particle states and and tracing over the modes in region II, we getwith |mn⟩=. The partial transpose criterion provides a necessary and sufficient condition for entanglement in a mixed state of two qubits [11]: if at least one eigenvalue of the partial transpose isnegative, the density matrix is entangled. Interchanging Ali ce’s qubits, we obtain an eigenvalue of the partial transpose ,which is always negative for . Thus, the state is always entangled for any uniform acceleration of Bob. The logarithmic negativity is expressed asFor vanishing acceleration (), . For finite acceleration, the entanglement is degraded by the Unruh effect just as shown in Fig. 3. We find that in the range , for larger , the initial entanglement is higher, but it is not always degraded to a higher degree. It should be noted that for the final entanglement of the initial state is higher than that of the maximally entangled state, i.e., , and forFIG. 4.(Color online)Mutual information of the fermionic modes versus r for different .the maximal final entanglement is . In the range , the larger , the weaker the initial entanglement and the lower the final entanglement. Unlike the behaviors of the bosonic case, except for the maximally entangled state, the same initial entanglement of the fermionic modes for and will be degraded along two different trajectories and asymptotically reach two different nonvanishing minimum values in the infinite-acceleration limit() due to the coupling of α and the trigonometric functions related to r. In the infinite-acceleration limit, which means that the state is always entangled. This is in strong contrast to the bosonic case and shows that the fermionic system can be used as a resource forperforming certain quantum-information-processing tasks.As for the bosonic case, we go through the same process again and get the mutual information for these fermionic modes,whose trajectories versus r for different αare shown by Fig. 4. For vanishing acceleration, the initial mutual information is, whose behaviors are thefor the bosonic modes. The mutual information same as those of Ibibecomes smaller as the acceleration increases, and again we surprisingly find that the same initial mutual information for and will be degraded along two different trajectories except for the maximally entangled state. In the infinite-acceleration limit the mutual information converges to , which is just half of . This behavior is reminiscent of that seen for the bosonic case, so we conclude thatwhich is independent of α and the type of field.It should be noted that, if we set the initial entangled state aswe will have the same behavior of the entanglement degradation for the same α that is shown in Figs. 1–4.Summarizing, the entanglement of the scalar and Dirac fields in noninertial frames is degraded by the Unruh effect as Bob’s rate of acceleration increases, but their behaviors of the degradation of entanglement are different for the same initial state parameter α. It is surprisingly found that the same initial entanglement for α andwill be degraded along two different trajectories except for the maximally entangled state, which just shows the inequivalence of the quantization for a free field in Minkowski and Rindler coordinates. In the infinite-acceleration limit, which can be applied to the case of Alice falling into a black hole while Bob barely escapes, the state does not have distillable entanglement for any α for the scalar field but always remains entangled to a degree that is dependent on α for the Dirac field. It should be noted that, for , we will have the maximal final entanglement for the fermionic state in this limit. Further analysis shows that, with increasing acceleration parameter r, the mutual information is degraded to a nonvanishing minimum value which is dependent on α forthese two fields. However, it is interesting to note that the mutual information in the infinite-acceleration limit equals just half of the initial mutual information, independently of α and the type of field.This work was supported by the National Natural Science Foundation of China under Grant No. 10675045; the FANEDD under Grant No. 200317; the Hunan Provincial Natural Science Foundation of China under Grant No. 07A0128; and the construct program of key disciplines in Hunan Province.References[1] A. Peres and D. R. Terno, Rev. Mod. Phys. 76, 93 (2004); D.Boschi, S. Branca, F. De Martini, L. Hardy, and S. Popescu, Phys. Rev. Lett. 80, 1121 (1998); J. W. Pan, C. Simon, C.Brukner, and A. Zeilinger, Nature (London) 410, 1067 (2001); S. J. van Enk and T. Rudolph, Quantum Inf. Comput. 3, 423 (2003).[2] D. Bouwmeester, A. Ekert, and A. Zeilinger, The Physics of Quantum Information (Springer-Verlag, Berlin, 2000).[3] L. Bombelli, R. K. Koul, J. Lee, and R. D. Sorkin, Phys. Rev.D 34, 373 (1986); C. Callan and F. Wilzcek, Phys. Lett. B 333, 55 (1994).[4] S. W. Hawking, Commun. Math. Phys. 43, 199, 1975; Phys.Rev.D 14, 2460, (1976); H. Terashima, ibid. 61, 104016,2000.[5] A. Peres, P. F. Scudo, and D. R. Terno, Phys. Rev. Lett. 88, 230402 (2002); R. M.Gingrich and C.Adami, ibid. 89, 270402 (2002); P. M. Alsing and G. J. Milburn, ibid. 91, 180404 (2003).[6] I. Fuentes-Schuller and R. B. Mann, Phys. Rev. Lett. 95, 120404 (2005).[7] P. M. Alsing, I. Fuentes-Schuller, R. B. Mann, and T. E.Tessier, Phys. Rev. A 74, 032326 (2006).[8] P. C. W. Davies, J. Phys. A 8, 609 (1975); W. G. Unruh, Phys.Rev. D 14, 870 (1976).[9] R. M. Wald, General Relativity (University of Chicago Press,Chicago, 1984).[10] N. D. Birrell and P. C. W. Davies, Quantum Fields in CurvedSpace (Cambridge University Press, New York, 1982).[11] A. Peres, Phys. Rev. Lett. 77, 1413 (1996).[12] G. Vidal and R. F. Werner, Phys. Rev. A 65, 032314 (2002); M. B. Plenio, Phys. Rev. Lett. 95, 090503 (2005).[13] R. S. Ingarden, A. Kossakowski, and M. Ohya, Information Dynamics and Open Systems—Classical and Quantum Approach (Kluwer Academic Publishers, Dordrecht, 1997).。