化工毕业设计外文翻译
毕设外文翻译是什么意思(两篇)
引言概述:在现代高等教育中,毕业设计(或称为毕业论文、学士论文等)是学生完成学业的重要环节。
而对于一些特定的专业,例如翻译专业,有时候还需要完成外文翻译这一项任务。
本文将探讨毕设外文翻译的意义和目的,以及为什么对翻译专业的学生而言这一任务极其重要。
正文内容:1.提高翻译能力和技巧外文翻译是一项对翻译专业学生而言十分重要的任务,通过进行外文翻译,学生们可以通过实践提高自己的翻译能力和技巧。
在这个过程中,他们可以学习如何处理不同类型的外文文本,熟悉不同领域的专业术语,并掌握一些常用的翻译技巧和策略。
2.扩展语言和文化知识毕设外文翻译要求学生们对翻译语言的相关知识和背景有一定的了解。
在进行翻译时,学生们需要遵循目标语言的语法规则,并确保所翻译的内容准确、清晰地传达源语言的意义。
通过这一过程,学生们可以进一步扩展自己的语言和文化知识,提高自己的跨文化沟通能力。
3.提供实践机会毕设外文翻译为学生们提供了一个实践的机会,让他们能够将在课堂上所学到的理论知识应用于实际操作中。
通过实践,学生们可以对所学知识的理解更加深入,同时也可以发现并解决实际翻译过程中的问题和挑战。
这对于学生们将来从事翻译工作时具备更好的实践能力和经验具有重要意义。
4.培养翻译专业素养毕设外文翻译要求学生们具备良好的翻译专业素养。
在进行翻译过程中,学生们需要保持专业的态度和责任心,严谨地对待每一个翻译任务。
他们需要学会如何进行翻译质量的评估和控制,以确保最终翻译稿的准确性和流畅性。
这一系列的要求和实践,可以帮助学生们培养出色的翻译专业素养。
5.提升自我学习和研究能力毕设外文翻译要求学生们进行广泛的文献阅读和研究,以便更好地理解所翻译的内容,并找到适当的翻译方法和策略。
在这个过程中,学生们需要培养自己的自主学习和研究能力,提高对学术和专业领域的敏感性,并能够独立思考和解决问题。
这将对学生们未来的学术研究和进一步的职业发展产生积极的影响。
总结:引言概述:毕业设计外文翻译(Thesis Translation)是指在毕业设计过程中,对相关外文文献进行翻译,并将其应用于研究中,以提供理论支持和参考。
快速点特征直方图(FPFH)三维配准-化工大学毕业设计(外文翻译)
快速点特征直方图(FPFH)三维配准Radu Bogdan Rusu, Nico Blodow, Michael BeetzIntelligent Autonomous Systems, Technische Universit¨at M¨unchen信计1001 鄂求实2010016363摘要:在我们最近的工作[1],[2],我们提出具有稳定的多维度特征点特征直方图(PFH),它描述了三维点云数据集的一个点p周围的局部几何特征。
在本文中,我们修改他们的数学表达式并对重叠点云的三维配准问题的稳定性和复杂性进行了严格的分析。
更具体地说,我们提出几个优化方法,由任意快取以前计算的值,或通过修改他们的理论公式大大减少计算时间。
在一个新的类型,后者的结果局部特征,称为快速点特征直方图(FPFH)它保留了大部分PFH的辨别力。
此外,我们提出了为实时应用FPFH功能的一个算法的在线计算。
为了验证我们结果,我们展示他们三维配准的效率,并提出了一种新的以样本为基础共识的方法,使两个数据集到局部非线性的收敛域优化:SAC-IA(抽样一致初始对准)。
1. 引言在本文中,我们解决的各种重叠的三维点云数据视图一致对准,形成一个完整的模型(在一个刚性的意义上)的问题,也称为三维配准。
解决的办法可以将他转化成一个优化问题,即,在适当的度量空间中,通过求解最佳旋转而转换(6度)使这样的数据集之间的重叠区域之间的距离是最小的。
在空间初始未知和重叠未知的情况下,这个问题就更加困难和寻找最佳解决方案的最优化技术更容易失败。
这是因为函数优化是多维的,局部最优解决方案可能接近全局。
三维刚性配准方法的简单分类可以基于底层的优化类型,方法:全局或局部。
在第一类中也是最广为人知的都是基于全局随机采用遗传算法优化[3]或进化技术[4],其主要缺点是实际计算时间。
很多在三维配准完成的工作其实属于第二类,至今最流行配准方法无疑是在最近点迭代(ICP)算法[5],[6]。
毕业设计外文翻译译文
1 工程概论1.1 工程专业1.2 工业和技术1.3 现代制造业工程专业1 工程行业是历史上最古老的行业之一。
如果没有在广阔工程领域中应用的那些技术,我们现在的文明绝不会前进。
第一位把岩石凿削成箭和矛的工具匠是现代机械工程师的鼻祖。
那些发现地球上的金属并找到冶炼和使用金属的方法的工匠们是采矿和冶金工程师的先祖。
那些发明了灌溉系统并建造了远古世纪非凡的建筑物的技师是他们那个时代的土木工程师。
2 工程一般被定义为理论科学的实际应用,例如物理和数学。
许多早期的工程设计分支不是基于科学而是经验信息,这些经验信息取决于观察和经历,而不是理论知识。
这是一个倾斜面实际应用的例子,虽然这个概念没有被确切的理解,但是它可以被量化或者数字化的表达出来。
3 从16、17世纪当代初期,量化就已经成为科学知识大爆炸的首要原因之一。
另外一个重要因素是实验法验证理论的发展。
量化包含了把来源于实验的数据和信息转变成确切的数学术语。
这更加强调了数学是现代工程学的语言。
4 从19世纪开始,它的结果的实际而科学的应用已经逐步上升。
机械工程师现在有精确的能力去计算来源于许多不同机构之间错综复杂的相互作用的机械优势。
他拥有能一起工作的既新型又强硬的材料和巨大的新能源。
工业革命开始于使用水和蒸汽一起工作。
从此使用电、汽油和其他能源作动力的机器变得如此广泛以至于它们承担了世界上很大比例的工作。
5 科学知识迅速膨胀的结果之一就是科学和工程专业的数量的增加。
到19世纪末不仅机械、土木、矿业、冶金工程被建立而且更新的化学和电气工程专业出现了。
这种膨胀现象一直持续到现在。
我们现在拥有了核能、石油、航天航空空间以及电气工程等。
每种工程领域之内都有细分。
6 例如,土木工程自身领域之内有如下细分:涉及永久性结构的建筑工程、涉及水或其他液体流动与控制系统的水利工程、涉及供水、净化、排水系统的研究的环境工程。
机械工程主要的细分是工业工程,它涉及的是错综复杂的机械系统,这些系统是工业上的,而非单独的机器。
毕业设计(论文)外文翻译(原文)
编号:毕业设计(论文)外文翻译(原文)院(系):桂林电子科技大学职业技术学院专业:工商企业管理学生姓名:方智立学号:010*********指导教师单位:桂林电子科技大学职业技术学院姓名:朱芸芸职称:讲师2016年 4 月 1 日Marketing Strategy Analysis of SportsAbstractSports market is a special industry market, which for provide exchange of sports tangible products and services market. Sports market including fixed type, such as sports facilities, sports goods market, Mobile market, such as all kinds of sports service provided by the fitness club. Sports tourism and advertising business, sports goods should be consumers to accept, and occupy a larger market. If success of the sports marketing involves many factors. According to the specific characteristics of sports marketing, develop and implement appropriate marketing strategy is very important. Sports marketing strategy is to the sports business units within a certain period or stage marketing campaign's overall development plan of decision making.This paper argues that the marketing strategy can be further subdivided into market positioning strategy, market timing strategy, market entry strategy, market development strategy, market competition strategy, Choose a strategy, must conform to the enterprise's own competitive position, product status, to grasp the market opportunity, determined according to the demands of consumers. In this paper, the sports market segmentation marketing strategy for the market positioning strategy, market timing strategy, market entry strategy, market development strategy, market competition strategy, and discusses the sports marketing how to carry out strategic choice.Keywords: Sports bazaar ; Sports marketing; Marketing strategy1.Sports marketing strategy and characteristics1.1Sports marketing strategyStrategy refers to the planning of overall and profound things. Sports marketing strategy refers to the commodity business units under the guidance of modern marketing concept, to achieve its economic goal for enterprise in a certain period of the overall design and planning of marketing development.Inan increasingly competitive market circumstances, sports business units in order to effectively carry out business activities, to achieve its business objectives, must understand and based on the characteristics of marketing concepts and strategies, and Target the demand of the market, comprehensive analysis and marketing of various environmental factors, choose effective market strategy in the background.1.2The characteristics of the sports marketing strategySports marketing strategy has sports business units within a certain period or stage marketing campaign's overall development plan of decision making. It has the characteristics of the following.(1) Overall importance.Sports marketing strategy is a matter of the global business units, including two aspects the meaning of this global:on the one hand, Sports marketing strategy is the overall design, the development of the business units, including overall planning and the overall strategy and means.On the other hand, Sports marketing strategy decision is a matter of global business units and their all-round development in the future.(2)Secular.Sports marketing strategy is really about the future of sports business units: to achieve the goals of sports marketing strategy, will make the sports business units to produce qualitative leap, but this is not usually that can be done in the short term.Important, sports business units of marketing strategy on the strategic period not only very important to enterprise's survival and development, but also to the long-term development of enterprises play an important role.(3) Systematicness.Sports systemic marketing refers to business units, each part of the work of each link is a contact each other, are closely related to the organic unity of the whole.System have layers, the size and the primary and secondary division, at the next lower level to obey and serve at the next higher level.For a certain sports and business operation entity, the strategy of the whole enterprise as a whole system engineering to overall arrangement, the pursuit of the overall development of the biggest benefits.(4)Adaptability.Sports marketing adaptability, refers to the sports marketing and business operation entity is easily affected by external and internal environment, when the environment changes, sports business units made to adapt themselves to the new environment of the characteristics of rapid response.Sports marketing of the external environment including the market demand, political or economic situation changes, policy and law changes. Similarly, sports business entities internal conditions change will impact on marketing.(5)Risk.Due to sports marketing strategy is the business unit for the marketing activities during the period development collection of expected decision, and this decision is absolutely impossible in various conditions fully mature and information fully, make and sports market, especially the intangible product variety and complexity of the market, make sports marketing strategy has the characteristics of uncertainty and instantaneity, many market opportunities tend to be a passes, no longer to, opportunity and risk coexist.2.Sports marketing strategy comprisedand choiceSports marketing strategies mainly include market positioning strategy, market timing strategy, market entry strategy, market development strategy, market competition strategy.2.1 Market orientation strategyMarket positioning refers to the sports business units according to the condition of market competition situation and its own resources, establish and develop differentiated competitive advantage, to make their own products in the consumer formed in the difference between each product unique image and is superior to the competition.This unique image can be tangible or intangible.Enterprise after analyzing the market environment, should highlight its own market advantage, establish market position, Which companies need to know on a certain level of paper generalizes, consumers mind what is the best sports products as expected.2.2 Market entry policyMarket entry strategy is the sports business units at the right time to capture the target market, how to appropriately in the two aspects of production capacity and sales ability to make reliable measures and guarantee, to ensure the decision-making of sports products successfully enter the market.Its content mainly includes the production capacity of decision-making and sales ability to form two aspects.(1) Capacity Decision. In the necessary time, sports business entities formtargetmarket capacity, is one of the important conditions to achieve market goal.Regardless of whether they are sports tangible products and intangible products, generally there are two alternative strategies.①Independent development strategy refers to both tangible products, the development of sports and development of sports intangible products. All on its own strength to expand production scale, enhance the comprehensive production capacity or adjust the structure of the comprehensive production capacity of enterprise, to adapt the demand of product combination structure. ②Comprehensive development strategy, mainly depend on the sports business units of the external forces, namely, through joint, collaboration, subcontract, form a new comprehensive production capacity. Due to participating in planning, control, coordination, etc, are more difficult. Therefore, sports business units must be good at optimizing collaborator, deal with the various cooperation of responsibility, right and benefit, to maintain good relations of cooperation.(2) Sales ability decision. A sports product to enter and occupy the market, production enterprise must have the necessary sales ability and the ability to penetrate the market.Sales ability decision-making main consideration circulation channels and sales, product should be considered when making decisions, market, enterprise, social environment and the factors such as economic effect.2.3 Market development strategyMarket development strategy refers to the perspective of market prospects, the choice of market development means, usually includes two kinds of intensive development and diversified development main form.(1)Intensive development.When some kind of sports products in the market has the potential of further development, the choice of market penetration, product development and market development of three kinds of intensive development form. As the tangible products market, in sports and intangible products are common market and applicable.①Market penetration. on the basis of the existing market scale, increase the sales of existing products. Can use a variety of measures, consolidate old customers, increase the new user. ②Product development Is through developing and improving existing products, make its have some new properties and USES, meet the social demand more. ③market development. Refers to an enterprise that open up new product sales market, in order to increase sales.(2) Diversified development.Diversity is also called the diversification, basically have concentricity scattered scattered, horizontal dispersion and the integrityof three. ①Concentricity is sports business unit USES the original dispersed development technology and the characteristics, with its as the core, the development use different structure similar products. ②Scattered level of sexual development.Was used in the original market advantage, has occupied the market development of technology, nature and purpose of different products. For example, Sports club olicy makers, can through the player transfer channels, to sell players, profit.Others use their sports club or the player's social awareness to participate in the sales promotion of goods, in order to obtain profits. ③Integrity of dispersed development. Refers to the sports business units to expand the business into its original business, technology, market and the product has no connection in the industry. Such as the sports department construction and run a catering and service hotels, hotels, entertainment city, charge for parking lot, etc., is the form of scattered holistic development. Implement the diversification development, can improve the ability of sports business units to adapt to the environment, reduce the risk of a single business, at the same time, may be more fully use of all kinds of resources within the enterprise, make its have more potential development opportunities. However, the development of decentralized often leads to complication of operation and management, and business operation entities such as diversifying some problems.2.4Strategic Marketing CompetitionThe rules of the development of the market is superior bad discard, its characteristic is the petition can promote the economic development of the enterprise and the improvement of economic benefits.Enterprises should establish a clear concept of competition, flexible use of price and non-price competition means, take a man without I have, people have my good, good people knew, new I cheap, cheap I turn the principle and method of making enterprise competitive strategy, must accomplish know fairly well the competition environment and competition situation, can with ease.Enterprise competition environment factors mainly refers to the enterprise in addition to the social and cultural environment stress factors of various aspects, such as management scientist professor Michael porter of Harvard University famous the competitive offer slightly above, an enterprise usually exist competition pressure from five aspects, namely the industry competition pressure, potential to join the pressure from the industry, suppliers forward pressure (by providing raw materials or semi-finished products, to develop into their production products), buyers.(1) The overall competitive strategy. Under different conditions, the enterprise facing the pressure of competition is different, the analysis of the pressure of competition is to understand the purpose of each kind of competition situation of power, so as to make effective competition strategy.Under normal circumstances, the sports business units of competition strategy in general have a low cost strategy, product differentiation strategy and intensive strategy. ①low-cost strategy. Low cost strategy is to point to in under the premise of guarantee the quality of products and services, efforts to reduce the cost of production and sales so that the enterprise product prices lower than competitors' prices, with rapidly expanding sales increase market share. ②Product differentiation strategies. Product differentiation strategy is to point to create a unique characteristic of the enterprise products, to develop unique products or marketing programs, for in such aspects as product or service than competitors are unique. Thus to obtain the difference advantage.The United States, for example, "NIKE" brand sports shoes, NIKE production due to the appearance of novel design, the innovation of the use function and unique, and exquisite packaging, etc., although the price is surprisingly expensive, but occupies considerable market in China, the teenagers are very loving. ③Intensive strategy. Intensive strategy refers to the enterprises focus on one or several market segments provide the most effective service, better meet certain customers with different needs, so as to strive for the local competitive advantage. It is little different from the above three kinds of overall competition strategy, successfully implement these three strategies need different resources and decision-making, also should have different requirements on organization and management.(2) The competitive strategy of enterprises of different competitive position. Where the status of enterprise in market competition, the enterprise can be divided into: market leader, market challenger, market follower. Different competitive position of enterprises, should choose different market competitive strategy.①Dominant market competition strategy. Market power refers to the related products has the highest market share. Such as the current market position and stable dominated by clothing JinMeiLong, "ADIDAS", they are price changes, new product development, sales channel width and promotional efforts in a dominant position, recognized by other sports enterprises. ②The challenger market competition strategy. Market challenger refers to those in a secondary position in the market of the enterprise, such as "lining" brand garment enterprises .Market challenger to choosechallenge object is closely related to the strategic target, for a same object has different goals and strategies Such as attack market leader to gain the market share and product advantage ;Attack power with yourself quite seize its market position; Attacking small businesses taking their customers even small business itself."Lining" to win market price advantage to the international brand, with product quality advantages to gain "anta" challenger "peak" brand's market share. ③Followers of the market competition strategy. Market followers is to point to in a secondary position, under the conditions of "coexistence" market for as much as possible the benefit of the enterprise. Market followers don't need a lot of money, less risky and can obtain high profits, so many enterprises adopt this strategy, especially the sort of small or no fame and status of sports clothing enterprises. As the current sports "philharmonic" brand clothing enterprise in the enterprise.Reference[1] LiJianJun,WangCuiHua:The Research on Marketing Environment Enterprise of Things for Sports Use in China[J] Journal of NanJing institute of sport (social science edition) 2013.(10),36 ~ 48.[2] Discuss Sports market, products and marketing characteristics. [J] journal of xi ' an institute of physical education,2012.(3)101 ~109.[3] HuZhengMing Ed. Marketing Management[M].Shandong people's publishing house,2012.302 ~325.[4] [US]Kotler write. YuLiJun translate. Introduction to Marketing[M].Huaxia Publishing House,2011.333~389.[5] ZhangTongYao.Application areas to promote the marketing advantage analysis of third party logistics[J].Market of China,2010(3)128 ~136.[6] WangHuaiShu.The influence of the logistics quality of marketing[J].Teacher's Journal,2010(3)31 ~38.[7] WangChenWen.Shallow theory of logistics strategy in the role of marketing management[J].Chemical Enterprise Management,2009(7)175 ~178.。
本科毕业设计外文翻译(中文)
本科生毕业设计(论文)外文翻译外文原文题目:Real-time interactive optical micromanipulation of a mixture of high- and low-index particles中文翻译题目:高低折射率微粒混合物的实时交互式光学微操作毕业设计(论文)题目:阵列光镊软件控制系统设计姓名:任有健学院:生命学院班级:06210501指导教师:李勤高低折射率微粒混合物的实时交互式光学微操作Peter John Rodrigo Vincent Ricardo Daria Jesper Glückstad丹麦罗斯基勒DK-4000号,Risø国家实验室光学和等离子研究系jesper.gluckstad@risoe.dkhttp://www.risoe.dk/ofd/competence/ppo.htm摘要:本文论证一种对于胶体的实时交互式光学微操作的方法,胶体中包含两种折射率的微粒,与悬浮介质(0n )相比,分别低于(0L n n <)、高于(0H n n >)悬浮介质的折射率。
球形的高低折射率微粒在横平板上被一批捕获激光束生成的约束光势能捕获,捕获激光束的横剖面可以分为“礼帽形”和“圆环形”两种光强剖面。
这种应用方法在光学捕获的空间分布和个体几何学方面提供了广泛的可重构性。
我们以实验为基础证实了同时捕获又独立操作悬浮于水(0 1.33n =)中不同尺寸的球形碳酸钠微壳( 1.2L n ≈)和聚苯乙烯微珠( 1.57H n =)的独特性质。
©2004 美国光学学会光学分类与标引体系编码:(140.7010)捕获、(170.4520)光学限制与操作和(230.6120)空间光调制器。
1 引言光带有动量和角动量。
伴随于光与物质相互作用的动量转移为我们提供了在介观量级捕获和操作微粒的方法。
过去数十年中的巨大发展已经导致了在生物和物理领域常规光学捕获的各种应用以及下一代光学微操作体系的出现[1-5]。
本科毕业设计(论文)外文翻译
华南理工大学本科毕业设计(论文)翻译班级姓名学号指导教师填表日期中文译名水溶性过度金属咔咯配合物对DNA连接和氧化裂解的作用外文原文名DNA Binding and Oxidative Cleavage by a Water-soluble CarboxylManganese(III) Corrole外文原文版出处Chinese Journal of Chemistry,2013,V ol.31(10)译文:吸收光谱,荧光光谱和CD光谱,以及粘度测量已经研究了小牛胸腺DNA(ct-DNA)与锰的咔咯配合物——5,10,15-三(4-羧基苯基)咔咯的相互作用。
结果表明锰的咔咯配合物通过外部沟与ct-DNA结合,该结合常数K b为4.67×104 L•mol−1 。
在多种氧化剂存在下,由Mn III TCPC作用,ct-DNA裂解作用也被研究。
在过氧化氢或叔BuOOH存在下,Mn III TCPC 可以以缺口和线性形式切割超螺旋质粒pBR322,然而以KHSO5作为氧化剂却并没有观察到核酸酶的活性。
抑制剂试验表明,羟基自由基,单线氧没有参与Mn III TCPC为介质的DNA氧化裂解。
在这种氧化裂解反应中,氧代锰(V)的咔咯配合物是可能的活性中间体。
关键词:咔咯,锰,DNA联接,核酸酶活性引言在自然中,经由水解磷酸二酯是金属酶催化的DNA高效裂解的途径。
在过去几十年里,作为探索生物医药的工具和抗癌药物,旨在结合并切割DNA的过渡金属配合物已被广泛研究。
卟啉及其金属配合物在生命系统中无处不在并发挥了重要的作用,例如细胞色素P450,过氧化物酶和过氧化氢酶。
为追求潜在的应用,在光动力疗法,肿瘤显像,人工核酸酶中,许多水溶性卟啉,如阳离子型卟啉,磺化卟啉,羧酸卟啉已经合成,它们中的一些甚至被用在临床诊断和治疗中。
类似的研究已扩大到其他类似卟啉的分子。
咔咯大环化合物与卟啉是有许多相似之处。
咔咯金属配合物的许多性能与卟啉的比较已经引起了人们极大的兴趣。
毕业论文外文翻译-高层建筑供配电系统设计
毕业论文外文翻译-高层建筑供配电系统设计Design of Power Supply and Distribution System for High-rise BuildingsAbstractPower supply and distribution system is the lifeline of high-rise buildings. The design of power supply and distribution system is based on the characteristics of high-rise buildings, which requires not only reliable supply of power, but also the safety of electricity utilization and efficient energy consumption. In this paper, the design of power supply and distribution system for high-rise buildings is discussed, focusing on the selection of power supply mode, the design of power distribution system, the design of grounding system, the selection of electrical equipment and the design of lightning protection system. The application of advanced technologies such as distributed power supply, energy management and control system, and intelligent electrical equipment can improve the energy efficiency and utilization of high-rise buildings, reduce energy consumption and carbon emissions, and promote the development of green buildings.Keywords: high-rise buildings; power supply and distribution system; energy efficiency; green buildingsIntroductionHigh-rise buildings are an important symbol of urban development and represent the trend of modern architecture. With the continuous improvement of people’s living standards, the demand for high-rise buildings is increasing. Power supply and distribution system is an essential part of high-rise buildings, which plays a crucial role in the operation and maintenance of buildings. The design of power supply and distribution system for high-rise buildings needs to consider many factors, such as technical performance, safety and reliability, energy efficiency, economic benefits and environmental protection, etc. In recent years, with the rapid development of new energy and advanced technology, the design of power supply and distribution system for high-rise buildings has undergone significant changes, which focus on improving energy efficiency and reducing emissions. This paper analyzes the design of power supply and distribution system for high-rise buildings, summarizes the selection principles and design methods of various systems, and explores the application of new technologies to improve energy efficiency and promote the development of green buildings.1. Selection of Power Supply ModeThe power supply mode is the basic foundation of power supply and distribution system of high-rise buildings. In the selection of power supply mode, it is necessary to consider the characteristics of the building and the surrounding environment, and ensure the reliability and safety of power supply. Currently, the main power supply modes for high-rise buildings are grid-connected power supply and distributed power supply.1.1 Grid-connected Power SupplyGrid-connected power supply is a traditional power supply mode, which is widely used in high-rise buildings. It has the advantages of reliable power supply, convenient operation and maintenance, and stable voltage and frequency. However, grid-connected power supply is vulnerable to natural disasters such as typhoons and earthquakes, and may cause power outages, which will affect the normal life and work of residents. Moreover, the development of distribution network is limited by the capacity of the grid, which may cause overloaded operation and reduce the energy efficiency of high-rise buildings.1.2 Distributed Power SupplyDistributed power supply is a new power supply mode, which can improve the energy efficiency of high-rise buildings and reduce the dependence on the grid. Distributed power supply includes combined heat and power (CHP), solar power, wind power and other renewable energy sources. CHP is a highly efficient power generation technology, which can generate electricity and heat at the same time, and utilize the waste heat for air conditioning and domestic hot water. Solar power and wind power are clean energy sources, which have the advantages of zero emissions and long service life. Distributed power supply can reduce the transmission and distribution losses of power supply, and improve the energy efficiency of high-rise buildings. However, the initial investment of distributed power supply is relatively high, and the technical level of electrical equipment and maintenance management is demanding.2. Design of Power Distribution SystemThe power distribution system is responsible for the power transmission and distribution of high-rise buildings, which should ensure the safety and reliability of the power supply. The design of power distribution system includes the selection of power distribution equipment, the layout of power distribution room, and the calculation of power load.2.1 Selection of Power Distribution EquipmentThe selection of power distribution equipment should meet the requirements of technical performance, safety and reliability, and energy efficiency. The main power distribution equipment includes switchgear, transformer, busbar, distribution panel, etc. The switchgear should have the function of over-current protection, short-circuit protection and earth leakage protection, and should have the advantages of small volume, low noise and high reliability. The transformer should be selected according to the capacity and voltage level, and should have the advantages of low loss, high efficiency and small size. The busbar should have the advantages of high strength, good conductivity and low resistance. The distribution panel should have the functions of metering, control, protection and communication, and should be easy to operate and maintain.2.2 Layout of Power Distribution RoomThe layout of power distribution room should be reasonable and convenient for operation and maintenance. The power distribution room should be located near the power supply entrance, and should have the advantages of good ventilation, dry, clean and spacious. The power distribution room should be equipped with the necessary security measures, such as fire prevention, explosion-proof, and lightning protection.2.3 Calculation of Power LoadThe calculation of power load is the key to the design of power distribution system. The power load includes lighting load, air conditioning load, power load and special load, etc. The calculation of power load should take into account the diversity of load, the possibility of peak load, and the capacity of power supply equipment. The primary consideration is to ensure the safety and reliability of power supply, and then to improve the energy efficiency of power utilization.3. Design of Grounding SystemThe grounding system is an important safety measure for high-rise buildings. The design of grounding system should meet the requirements of electrical safety and electrostatic discharge protection.3.1 Electrical SafetyThe grounding system should have the functions of lightning protection, over-voltage protection, over-current protection and earth leakage protection, etc. The grounding resistance should be less than the specified value, and the grounding wire should have good conductivity and corrosion resistance. The grounding system should be comprehensively tested and maintained regularly.3.2 Electrostatic Discharge ProtectionThe electrostatic discharge protection is to prevent the accumulation of static electricity and the damage of electrical equipment. The design of electrostatic discharge protection includes the selection of anti-static grounding material, the setting of anti-static floor, and the installation of anti-static equipment. The electrostatic discharge protection is especially important for data centers and sensitive electrical equipment.4. Selection of Electrical EquipmentThe selection of electrical equipment is an important part of the design of power supply and distribution system for high-rise buildings. The selection of electrical equipment should meet the requirements of technical performance, safety and reliability, environmental protection and energy efficiency.4.1 Technical PerformanceThe electrical equipment should meet the relevant national and international standards, and have the characteristics of high efficiency, low noise, long service life and easy maintenance. The electrical equipment should have the functions of protection, control, measurement and communication, and should be compatible with the automation system.4.2 Safety and ReliabilityThe electrical equipment should have the functions of over-current protection, short-circuit protection, ground connection protection and lightning protection, etc. The electrical equipment should be installed and maintained by qualified personnel, and should be tested and checked regularly to ensure the safety and reliability of power supply and distribution system.4.3 Environmental Protection and Energy EfficiencyThe electrical equipment should have the advantages of environmental protection and energy efficiency, and should meet the requirements of green building standards. The electrical equipment should have the functions of power monitoring, energy management and control, and should be able to optimize the energy utilization and reduce the energy consumption.5. Design of Lightning Protection SystemThe lightning protection system is an important safety measure for high-rise buildings, which can prevent the damage of lightning to electrical equipment and human life. The design of lightning protection system includes the selection of lightning protection device, the installation of lightning rod, the connection of grounding wire, and the calculation of lightning protection zone.5.1 Selection of Lightning Protection DeviceThe lightning protection device should have the functions of lightning protection, over-voltage protection, surge protection and electromagnetic pulse protection, etc. The lightning protection device should be reliable and durable, and should meet the relevant national and international standards.5.2 Installation of Lightning RodThe lightning rod should be installed on the roof of high-rise buildings, and should be connected with the grounding system. The lightning rod should be placed in a high position, and should be made of light and strong materials, such as aluminum alloy or stainless steel. The lightning rod should be inspected regularly to ensure its effectiveness.5.3 Connection of Grounding WireThe grounding wire should be connected with the lightning rod, the grounding system, and the electrical equipment. The grounding wire should have the advantages of low resistance, good conductivity and corrosion resistance. The grounding wire should be tested and checked regularly to ensure its effectiveness.5.4 Calculation of Lightning Protection ZoneThe calculation of lightning protection zone is the basis for the design of lightning protection system. The lightning protection zone includes the direct lightning strike zone and the induced lightning zone. The direct lightning strike zone is the area covered by the lightning rod, and the induced lightning zone is the area beyond the direct lightning strike zone. The calculation of lightning protection zone should consider the characteristics of lightning, such as the stroke current, the distance from the lightning source, and the soil resistivity.ConclusionThe design of power supply and distribution system for high-rise buildings is a complex and important work. The selection of power supply mode, the design of power distribution system, the design of grounding system, the selection of electrical equipment, and the design of lightning protection system are the main aspects of the design of power supply and distribution system. The application of advanced technologies such as distributed power supply, energy management and control system, and intelligent electrical equipment can improve the energy efficiency and utilization of high-rise buildings, reduce energy consumption and carbon emissions, and promote the development of green buildings. The design of power supply and distribution system for high-rise buildings should adhere to the principles of safety, reliability, energy efficiency, economic benefits and environmental protection, and strive to create a better living and working space for residents.。
毕业论文设计外文资料翻译
毕业论文(设计)外文资料翻译学院:物理科学与电子技术学院专业:电子信息工程姓名:雷顺明学号:05223137外文出处:/colourful-rhyth ms-of-light-tango-r971913.htm附件:1、外文资料翻译译文;2、外文原文。
指导教师评语:该同学的外文资料翻译较准确,说明前期准备阶段的文献调研做了一定的工作,达到了预期目的。
签名:年月日附件1:外文资料翻译译文简易音乐彩灯控制器本例介绍一个简易音乐彩灯控制器,它的电路结构虽然非常简单,但使用效果很好,适宜初学者制作。
工作原理:简易音乐彩灯控制器电路如图所示,电路主要采用了一只晶闸管和一只三极管等组成。
220V交流电经灯串EL和二极管VD1一VD4桥式整流后变成约200V的脉动电压,一路加在晶闸管VT的两端作为VS工作所需的正向阳极电压;另一路经R1与R4分压,并经电容Cl滤波,在Cl两端可获得约3V左右稳定的直流电压,作为三极管VT的工作电压。
RP为声控灵敏度调节电位器,要求环境在无音乐声场时,调整RP使三极管VT刚好处于临界导通状态,这时VS的门极被VT短接无法获得触发电压,所以晶闸管VS处于关断态,流过彩灯串EL的电流极微,彩灯串EL不亮。
如果有人打开音响设备播放音乐时,压电陶瓷片B就拾取环境声波信号,并将其转换成相应的音频电压加在VT的发射结上。
强信号的负半周就使三极管VT退出导通态进入放大态,故VT的集电极电位升高,音乐信号愈强,VT集电极电位也就愈高,当高至晶闸管VS门极的触发电平时,VS开通彩灯串点亮发光。
弱信号时,VT集电极输出电平低于晶闸管门极的触发电平,晶闸管因交流电过零时即关断。
所以彩灯串EL能随环境声波信号的强弱而闪烁。
元器件选择VS选用普通小型塑封单向晶闸管,如2N6565,MCR100一8、BT169型等;VT选用或3DG8型硅NPN小功率三极管,要求电流放大系数β>200;VD1一VD4选用1 N4007型等硅整流二极管。
毕业设计(论文)外文资料翻译(学生用)
毕业设计外文资料翻译学院:信息科学与工程学院专业:软件工程姓名: XXXXX学号: XXXXXXXXX外文出处: Think In Java (用外文写)附件: 1.外文资料翻译译文;2.外文原文。
附件1:外文资料翻译译文网络编程历史上的网络编程都倾向于困难、复杂,而且极易出错。
程序员必须掌握与网络有关的大量细节,有时甚至要对硬件有深刻的认识。
一般地,我们需要理解连网协议中不同的“层”(Layer)。
而且对于每个连网库,一般都包含了数量众多的函数,分别涉及信息块的连接、打包和拆包;这些块的来回运输;以及握手等等。
这是一项令人痛苦的工作。
但是,连网本身的概念并不是很难。
我们想获得位于其他地方某台机器上的信息,并把它们移到这儿;或者相反。
这与读写文件非常相似,只是文件存在于远程机器上,而且远程机器有权决定如何处理我们请求或者发送的数据。
Java最出色的一个地方就是它的“无痛苦连网”概念。
有关连网的基层细节已被尽可能地提取出去,并隐藏在JVM以及Java的本机安装系统里进行控制。
我们使用的编程模型是一个文件的模型;事实上,网络连接(一个“套接字”)已被封装到系统对象里,所以可象对其他数据流那样采用同样的方法调用。
除此以外,在我们处理另一个连网问题——同时控制多个网络连接——的时候,Java内建的多线程机制也是十分方便的。
本章将用一系列易懂的例子解释Java的连网支持。
15.1 机器的标识当然,为了分辨来自别处的一台机器,以及为了保证自己连接的是希望的那台机器,必须有一种机制能独一无二地标识出网络内的每台机器。
早期网络只解决了如何在本地网络环境中为机器提供唯一的名字。
但Java面向的是整个因特网,这要求用一种机制对来自世界各地的机器进行标识。
为达到这个目的,我们采用了IP(互联网地址)的概念。
IP以两种形式存在着:(1) 大家最熟悉的DNS(域名服务)形式。
我自己的域名是。
所以假定我在自己的域内有一台名为Opus的计算机,它的域名就可以是。
本科毕业设计(论文)外文翻译
重金属污染存在于很多工业的废水中,如电镀,采矿,和制革。
2.实验
2.1化学药剂
本实验所使用的药剂均为分析纯,如无特别说明均购买自日本片山化工。铅离子储备液通过溶解Pb(NO3)2配制,使用时稀释到需要的浓度。HEPES缓冲液购买自Sigma–Aldrich。5 mol/L的HCl和NaOH用来调整pH。
附5
华南理工大学
本科毕业设计(论文)翻译
班级2011环境工程一班
姓名陈光耀
学号201130720022
指导教师韦朝海
填表日期
中文译名
(1)巯基改性纤维素对葡萄糖溶液中铅的吸附(2)黄原酸化橘子皮应用于吸附水中的铅离子
外文原文名
(1)Adsorption of Pb(II) from glucose solution on thiol-functionalized cellulosic biomass
2.5分析方法
铅离子的浓度用分光光度计在616 nm波长处用铅与偶氮氯膦-III络合物进行分析。葡萄糖含量采用苯酚—硫酸分光光度法测定。所有的实验均进行三次,已经考虑好误差。
3.结果和讨论
3.1FTIR分析和改性脱脂棉对铅(II)的吸附机制
图1是脱脂棉、改性脱脂棉在400-4000 cm-1(A)和2540-2560 cm-1(B)范围内的红外光谱图。可以看出,改性后改性脱脂棉的红外光谱图中在1735.71 cm-1处出现了一个新的吸收峰是酯基C=O的拉伸振动峰,可见改性脱脂棉中已经成功引入巯基官能团。同时,在2550.52 cm-1出现的一个新吸收峰代表的是S-H官能团的弱吸收峰,更深一层的证明了巯基已经嫁接到脱脂棉上。图1(b)是2540-2560 cm-1光谱范围的一个放大图像,可以清楚的观察到S-H官能团的弱吸收峰。进一步证明了酯化改性脱脂棉引入巯基是成功的。而从吸附后的曲线可以看到,2550.52cm-1处S-H的吸收峰消失,证明了硫原子和Pb(II)络合物的形成,同时1735.71cm-1处C=O的吸收峰强度看起来有轻微的减弱可能也是和Pb(II)的络合吸附有关。
华南理工大学 毕业设计 外文翻译
华南理工大学本科毕业设计(论文)翻译班级土木工程三班姓名王剑锋学号 200930132042指导教师骆冠勇填表日期 2013年4月21日中文译名一种用于预测拉森钢板桩弯曲强度的数值模型外文原文名 A numerical model for predicting the bending strength of Larssen steel sheetpiles外文原文版出处Journal of Constructional Steel Research 58 (2002) 1361–1374译文:一种用于预测拉森钢板桩弯曲强度的数值模型R.J. Crawford, M.P. Byfield摘要拉森桩为U形横截面并通过可滑动的接头连接在一起组成码头岸壁,围堰,和其他类型的挡土墙。
由于滑动接头位于桩墙的中心线上,相互连接桩的桩间滑移可能导致桩墙70%的弯曲强度折减。
这种桩间滑移可以通过安装成对的带有卷曲的锁头的桩来部分阻止。
然而,像非卷曲桩一样弯曲强度很难被预测,因为这种联锁桩依然存在桩间滑移。
本文提出了一种用于预测联锁拉森桩弯曲应力以及压应力的数值方法。
通过测试1:6比例大小的铝制拉森桩微缩模型的数据与数值模型计算结果进行比较,结果表明数值模型所预测的应力与实际实验结果接近一致。
同时本数值模型也可用于钢板桩的设计生产,以达到使用最少的材料来达到最大的弯曲强度的目的。
C 2002爱思唯尔股份有限公司保留解释权利关键词:行业规范;组合结构;拉森桩;桩结构;挡土墙;钢结构1.介绍钢板桩被广泛运用于全世界。
工程上经常使用的两种钢板桩是U型拉森钢板桩和Z型钢板桩。
两种类型的钢板桩桩都是利用沿着构件长度方向的锁头连接成有缝的连续墙结构。
根据欧洲标准化委员会引入的欧3标准第五部分,U型钢板桩锁头连接部分的下滑位移的影响不能忽视(见图1 步骤1)。
如果钢板桩单肢的相对滑移严重,则钢板桩的弯曲强度会下降到整体强度的70%,我们将其称为钢板桩模量下降。
毕业设计论文化学系毕业论文外文文献翻译中英文
毕业设计论文化学系毕业论文外文文献翻译中英文英文文献及翻译A chemical compound that is contained in the hands of the problemsfor exampleCatalytic asymmetric carbon-carbon bond formation is one of the most active research areas in organic synthesis In this field the application of chiral ligands in enantioselective addition of diethylzinc to aldehydes has attracted much attention lots of ligands such as chiral amino alcohols amino thiols piperazines quaternary ammonium salts 12-diols oxazaborolidines and transition metal complex with chiral ligands have been empolyed in the asymmetric addition of diethylzinc to aldehydes In this dissertation we report some new chiral ligands and their application in enantioselective addition of diethylzinc to aldehydes1 Synthesis and application of chiral ligands containing sulfur atomSeveral a-hydroxy acids were prepared using the literature method with modifications from the corresponding amino acids valine leucine and phenylalanine Improved yields were obtained by slowly simultaneous addition of three fold excess of sodium nitrite and 1 tnolL H2SO4 In the preparation of a-hydroxy acid methyl esters from a-hydroxy acids following the procedure described by Vigneron a low yield 45 was obtained It was found that much better results yield 82 couldbe obtained by esterifying a-hydroxy acids with methanol-thionyl chlorideThe first attempt to convert S -2-hydroxy-3-methylbutanoic acid methyl ester to the corresponding R-11-diphenyl-2-mercapto-3-methyl-l-butanol is as the following S-2-Hydroxy-3-methylbutanoic acid methyl ester was treated with excess of phenylmagnesium bromide to give S -11-diphenyl-3-methyl-12-butanediol which was then mesylated to obtain S -11-diphenyl-3-methyl-2-methanesulfonyloxy -l-butanol Unfortunately conversion of S-11-diphenyl-3-methyl-2- methanesulfonyloxy -l-butanol to the corresponding thioester by reacting with potassium thioacetate under Sn2 reaction conditions can be achieved neither in DMF at 20-60 nor in refluxing toluene in the presence of 18-crown-6 as catalyst When S -1ll-diphenyl-3-methyl-2- methane sulfonyloxy -l-butanol was refluxed with thioacetic acid in pyridine an optical active epoxide R-22-diphenyl -3-isopropyloxirane was obtained Then we tried to convert S -11-diphenyl-3-methyl-l2-butanediol to the thioester by reacting with PPh3 DEAD and thioacetic acid the Mitsunobu reaction but we failed either probably due to the steric hindrance around the reaction centerThe actually successful synthesis is as described below a-hydroxy acid methyl esters was mesylated and treated with KSCOCH3 in DMF to give thioester this was than treated with phenyl magnesium bromide to gave the target compound B-mercaptoalcohols The enantiomeric excesses ofp-mercaptoalcohols can be determined by 1H NMR as their S -mandeloyl derivatives S -2-amino-3-phenylpropane-l-thiol hydrochloride was synthesized from L-Phenylalanine L-Phenylalanine was reduced to the amino alcohol S -2-amino-3-phenylpropanol Protection of the amino group using tert-butyl pyrocarbonate gave S -2-tert-butoxycarbonylamino-3-phenylpropane-l-ol which was then O-mesylated to give S -2-tert-butoxycarbonylamino-3-phenylpropyl methanesulfonate The mesylate was treated with potassium thioacetate in DMF to give l-acetylthio-2-tert-butoxycarbonylamino-3-phenylpropane The acetyl group was then removed by treating with ammonia in alcohol to gave S -2-tert-butoxycarbonylamino-3-phenyl-propane-l-thiol which was then deprotected with hydrochloric acid to give the desired S-2-amino-3-phenylpropane-1-thiol hydrochlorideThe enantioselective addition of diethylzinc to aldehydes promoted by these sulfur containing chiral ligands produce secondary alcohols in 65-79 Synthesis and application of chiral aminophenolsThree substituted prolinols were prepared from the naturally-occurring L-proline using reported method with modifications And the chiral aminophenols were obtained by heating these prolinols with excess of salicylaldehyde in benzene at refluxThe results of enantioselective adBelow us an illustration forexampleN-Heterocyclic carbenes and L-Azetidine-2-carboxylicacidN-Heterocyclic carbenesN-Heterocyclic carbenes have becomeuniversal ligands in organometallic and inorganic coordination chemistry They not only bind to any transition metal with low or high oxidation states but also to main group elements such as beryllium sulfur and iodine Because of their specific coordination chemistry N-heterocyclic carbenes both stabilize and activate metal centers in quite different key catalytic steps of organic syntheses for example C-H activation C-C C-H C-O and C-N bond formation There is now ample evidence that in the new generation of organometallic catalysts the established ligand class of organophosphanes will be supplemented and in part replaced byN-heterocyclic carbenes Over the past few years this chemistry has become the field of vivid scientific competition and yielded previously unexpected successes in key areas of homogeneous catalysis From the work in numerous academic laboratories and in industry a revolutionary turningpoint in oraganometallic catalysis is emergingIn this thesis Palladium Ⅱ acetate and NN"-bis- 26-diisopropylphenyl dihydro- imidazolium chloride 1 2 mol were used to catalyze the carbonylative coupling of aryl diazonium tetrafluoroborate salts and aryl boronic acids to form aryl ketones Optimal conditions include carbon monoxide 1 atm in 14-dioxane at 100℃ for 5 h Yields for unsymmetrical aryl ketones ranged from 76 to 90 for isolated materials with only minor amounts of biaryl coupling product observed 2-12 THF as solvent gave mixtures of products 14-Dioxane proved to be the superior solvent giving higher yieldsof ketone product together with less biphenyl formation At room temperature and at 0℃ with 1 atm CO biphenyl became the major product Electron-rich diazonium ion substrates gave a reduced yield with increased production of biaryl product Electron-deficient diazonium ions were even better forming ketones in higher yields with less biaryl by-product formed 2-Naphthyldiazonium salt also proved to be an effective substrate givingketones in the excellent range Base on above palladium NHC catalysts aryl diazonium tetrafluoroborates have been coupled with arylboron compounds carbon monoxide and ammonia to give aryl amides in high yields A saturated yV-heterocyclic carbene NHC ligand H2lPr 1 was used with palladium II acetate to give the active catalyst The optimal conditions with 2mol palladium-NHC catalyst were applied with various organoboron compounds and three aryl diazonium tetrafluoroborates to give numerous aryl amides in high yield using pressurized CO in a THF solution saturated with ammonia Factors that affect the distribution of the reaction products have been identified and a mechanism is proposed for this novel four-component coupling reactionNHC-metal complexes are commonly formed from an imidazolium salt using strong base Deprotonation occurs at C2 to give a stable carbene that adds to form a a-complex with the metal Crystals were obtained from the reaction of imidazolium chloride with sodium t- butoxide Nal and palladium II acetate giving a dimeric palladium II iodide NHC complex The structure adopts a flat 4-memberedring u2 -bridged arrangement as seen in a related dehydro NHC complex formed with base We were pleased to find that chloride treated with palladium II acetate without adding base or halide in THF also produced suitable crystals for X-ray anaysis In contrast to the diiodide the palladium-carbenes are now twisted out of plane adopting a non-planar 4-ring core The borylation of aryldiazonium tetrafluoroborates with bis pinacolatoborane was optimized using various NHC ligand complexes formed in situ without adding base NN"-Bis 26-diisopropylphenyl-45-dihydroimidazolium 1 used with palladium acetate in THF proved optimal giving borylated product in 79 isolated yield without forming of bi-aryl side product With K2CO3 and ligand 1 a significant amount of biaryl product 24 was again seen The characterization of the palladium chloride complex by X-ray chrastallography deL-Azetidine-2-carboxylic acidL-Azetidine-2-carboxylic acid also named S -Azetidine-2-carboxylic acid commonly named L-Aze was first isolated in 1955 by Fowden from Convallaria majalis and was the first known example of naturally occurring azetidine As a constrained amino acid S -Azetidine-2-carboxylic acid has found many applications in the modification of peptides conformations and in the area of asymmetric synthesis which include its use in the asymmetric reduction of ketones Michael additions cyclopropanations and Diels-Alder reactions In this dissertation five ways for synthesize S-Azetidine-2-carboxylic acid were studied After comparing all methods theway using L-Aspartic acid as original material for synthesize S-Azetidine-2-carboxylic acid was considered more feasible All mechanisms of the way"s reaction have also been studied At last the application and foreground of S -Azetidine-2-carboxylic acid were viewed The structures of the synthetic products were characterized by ThermalGravity-Differential Thermal Analysis TG-DTA Infrared Spectroscopy IR Mass Spectra MS and 1H Nuclear Magnetic Resonance 1H-NMR Results showed that the structures and performances of the products conformed to the anticipation the yield of each reaction was more than 70 These can conclude that the way using L-Aspartie acid as original material for synthesize S -Azetidine-2-carboxylic acid is practical and effective杂环化合物生成中包含手性等问题如催化形成不对称碳碳键在有机合成中是一个非常活跃的领域在这个领域中利用手性配体诱导的二乙基锌和醛的不对称加成引起化学家的广泛关注许多手性配体如手性氨基醇手性氨基硫醇手性哌嗪手性四季铵盐手性二醇手性恶唑硼烷和过渡金属与手性配体的配合物等被应用于二乙基锌对醛的不对称加成中在本论文中我们报道了一些新型的手性配体的合成及它们应用于二乙基锌对醛的不对称加成的结果1含硫手性配体的合成和应用首先从氨基酸缬氨酸亮氨酸苯丙氨酸出发按照文献合成α-羟基酸并发现用三倍量的亚硝酸钠和稀硫酸同时滴加进行反应能适当提高反应的产率而根据Vigneron等人报道的的方法用浓盐酸催化从α-羟基酸合成α-羟基酸甲酯时只能获得较低的产率改用甲醇-二氯亚砜的酯化方法时能提高该步骤的产率从 S -3-甲基-2-羟基丁酸甲酯合成 R -3-甲基-11-二苯基-2-巯基-1-丁醇经过了以下的尝试 S -3-甲基-2-羟基丁酸甲酯和过量的格氏试剂反应得到 S -3-甲基-11-二苯基-12-丁二醇进行甲磺酰化时位阻较小的羟基被磺酰化生成 S -3-甲基-11-二苯基-2- 甲磺酰氧基 -1-丁醇但无论将 S -3-甲基-11-二苯基-2- 甲磺酰氧基 -1-丁醇和硫代乙酸钾在DMF中反应 20~60℃还是在甲苯中加入18-冠-6作为催化剂加热回流都不能得到目标产物当其与硫代乙酸在吡啶中回流时得到的不是目标产物而是手性环氧化合物 R -3-异丙基-22-二苯基氧杂环丙烷从化合物 S -3-甲基-11-二苯基-12-丁二醇通过Mitsunobu反应合成硫代酯也未获得成功这可能是由于在反应中心处的位阻较大造成的几奥斯塑手村犯体的合成裁其在不对称奋成中肠左用摘要成功合成疏基醇的合成路是将a-轻基酸甲酷甲磺酞化得到相应的磺酞化产物并进行与硫代乙酸钾的亲核取代反应得到硫酷进行格氏反应后得到目标分子p一疏基醇用p一疏基醇与 R 义一一甲氧基苯乙酞氯生成的非对映体经H侧NM吸测试其甲氧基峰面积的积分求得其ee值 3一苯基一氨基丙硫醇盐酸盐从苯丙氨酸合成斗3一苯基一氨基丙醇由L一苯丙氨酸还原制备氨基保护后得到习一3一苯基一2一叔丁氧拨基氨基一1一丙醇甲磺酞化后得到习一3一苯基一2一叔丁氧拨基氨基一1一丙醇甲磺酸酷用硫代乙酸钾取代后得匀一3-苯基一2一叔丁氧拨基氨基一1一丙硫醇乙酸酷氨解得习一3一苯基一2一叔丁氧拨基氨基一1一丙硫醇用盐酸脱保护后得到目标产物扔3一苯基屯一氨基丙硫醇盐酸盐手性含硫配体诱导下的二乙基锌与醛的加成所得产物的产率为65一79值为O井92手性氨基酚的合成和应用首先从天然的L一脯氨酸从文献报道的步骤合成了三种脯氨醇这些手性氨基醇与水杨醛在苯中回流反应得到手性氨基酚手性氨基酚配体诱导下的二乙基锌与醛的加成所得产物的产率为45一98值为0一90手性二茂铁甲基氨基醇的合成和应用首先从天然氨基酸绿氨酸亮氨酸苯丙氨酸和脯氨酸合成相应的氨基醇这些氨基醇与二茂铁甲醛反应生成的NO一缩醛经硼氢化钠还原得到手性二茂铁甲基氨基醇手性二茂铁甲基氨基醇配体诱导下的二乙基锌与醛的加成所得产物的产率为66一97下面我们举例说明一下例如含氮杂环卡宾和L-氮杂环丁烷-2-羧酸含氮杂环卡宾含氮杂环卡宾已广泛应用于有机金属化学和无机配合物化学领域中它们不仅可以很好地与任何氧化态的过渡金属络合还可以与主族元素铍硫等形成配合物由于含氮杂环卡宾不但使金属中心稳定而且还可以活化此金属中心使其在有机合成中例如C-H键的活化C-CC-HC-O和C-N键形成反应中有着十分重要的催化效能现有的证据充分表明在新一代有机金属催化剂中含氮杂环卡宾不但对有机膦类配体有良好的互补作用而且在有些方面取代有机膦配体成为主角近年来含氮杂环卡宾及其配合物已成为非常活跃的研究领域在均相催化这一重要学科中取得了难以想象的成功所以含氮杂环卡宾在均相有机金属催化领域的研究工作很有必要深入地进行下去本文研究了乙酸钯和NN双 26-二异丙基苯基 -45-二氢咪唑氯化物1作为催化剂催化芳基四氟硼酸重氮盐与芳基硼酸的羰基化反应合成了一系列二芳基酮并对反应条件进行了优化使反应在常温常压下进行一个大气压的一氧化碳14-二氧杂环己烷作溶剂100℃反应5h 不同芳基酮的收率达7690仅有微量的联芳烃付产物 212 反应选择性良好当采用四氢呋喃或甲苯作溶剂时得到含较多副产物的混合物由此可以证明14-二氧杂环己烷是该反应最适宜的溶剂在室温或0℃与一个大气压的一氧化碳反应联芳烃变成主产物含供电子取代基的芳基重氮盐常常给出较低收率的二芳基酮而含吸电子取代基的芳基重氮盐却给出更高收率的二芳基酮及较少量的联芳烃付产物实验证明2-萘基重氮盐具有很好的反应活性和选择性总是得到优异的反应结果在此基础上由不同的芳基四氟硼酸重氮盐与芳基硼酸一氧化碳和氨气协同作用以上述含氮杂环卡宾作配体与乙酸钯生成的高活性含氮杂环卡宾钯催化剂催化较高收率地得到了芳基酰胺优化的反应条件是使用2mol的钯-H_2IPr 1五个大气压的一氧化碳以氨气饱和的四氢呋喃作溶剂由不同的有机硼化合物与三种芳基重氮盐的四组份偶联反应同时不仅对生成的多种产物进行了定 L-氮杂环丁烷-2-羧酸L-氮杂环丁烷-2-羧酸又称 S -氮杂环丁烷-2-羧酸简称为L-Aze1955年由Fowden从植物铃兰 Convallaria majalis 中分离得到成为第一个被证实的植物中天然存在的氮杂环丁烷结构作为一种非典型的氨基酸已经发现 S -氮杂环丁烷-2-羧酸可广泛用于对多肽结构的修饰以及诸如不对称的羰基还原Michael 加成环丙烷化和Diels-Alder反应等不对称合成中的多个领域本文通过对 S -氮杂环丁烷-2-羧酸合成路线的研究综述了五种可行的合成路线及方法通过比较选用以L-天冬氨酸为初始原料合成 S -氮杂环丁烷-2-羧酸的路线即通过酯化反应活泼氢保护格氏反应内酰胺化反应还原反应氨基保护氧化反应脱保护等反应来合成 S -氮杂环丁烷-2-羧酸分析了每步反应的机理并对 S -氮杂环丁烷-2-羧酸的应用及前景给予展望通过热分析红外质谱核磁等分析手段对合成的化合物的结构进行表征结果表明所得的产物符合目标产物所合成的化合物的结构性能指标与设计的目标要求一致每步反应的收率都在70%以上可以判定以L-天冬氨酸为初始原料合成 S -氮杂环丁烷的路线方案切实可行。
毕业设计外文翻译英文
Bid Compensation Decision Model for Projectswith Costly Bid PreparationS.Ping Ho,A.M.ASCE 1Abstract:For projects with high bid preparation cost,it is often suggested that the owner should consider paying bid compensation to the most highly ranked unsuccessful bidders to stimulate extra effort or inputs in bid preparation.Whereas the underlying idea of using bid compensation is intuitively sound,there is no theoretical basis or empirical evidence for such suggestion.Because costly bid preparation often implies a larger project scale,the issue of bid compensation strategy is important to practitioners and an interest of study.This paper aims to study the impacts of bid compensation and to develop appropriate bid compensation strategies.Game theory is applied to analyze the behavioral dynamics between competing bidders and project owners.A bid compensation model based on game theoretic analysis is developed in this study.The model provides equilibrium solutions under bid compensation,quantitative formula,and quali-tative implications for the formation of bid compensation strategies.DOI:10.1061/(ASCE )0733-9364(2005)131:2(151)CE Database subject headings:Bids;Project management;Contracts;Decision making;Design/build;Build/Operate/Transfer;Construction industry .IntroductionAn often seen suggestion in practice for projects with high bid preparation cost is that the owner should consider paying bid compensation,also called a stipend or honorarium,to the unsuc-cessful bidders.For example,according to the Design–build Manual of Practice Document Number 201by Design–Build In-stitute of America (DBIA )(1996a ),it is suggested that that “the owner should consider paying a stipend or honorarium to the unsuccessful proposers”because “excessive submittal require-ments without some compensation is abusive to the design–build industry and discourages quality teams from participating.”In another publication by DBIA (1995),it is also stated that “it is strongly recommended that honorariums be offered to the unsuc-cessful proposers”and that “the provision of reasonable compen-sation will encourage the more sought-after design–build teams to apply and,if short listed,to make an extra effort in the prepara-tion of their proposal.”Whereas bid preparation costs depend on project scale,delivery method,and other factors,the cost of pre-paring a proposal is often relatively high in some particular project delivery schemes,such as design–build or build–operate–transfer (BOT )contracting.Plus,costly bid preparation often im-plying a large project scale,the issue of bid compensation strat-egy should be important to practitioners and of great interest of study.Existing research on the procurement process in constructionhas addressed the selection of projects that are appropriate for certain project delivery methods (Molenaar and Songer 1998;Molenaar and Gransberg 2001),the design–build project procure-ment processes (Songer et al.1994;Gransberg and Senadheera 1999;Palaneeswaran and Kumaraswamy 2000),and the BOT project procurement process (United Nations Industrial Develop-ment Organization 1996).However,the bid compensation strat-egy for projects with a relatively high bid preparation cost has not been studied.Among the issues over the bidder’s response to the owner’s procurement or bid compensation strategy,it is in own-er’s interest to understand how the owner can stimulate high-quality inputs or extra effort from the bidder during bid prepara-tion.Whereas the argument for using bid compensation is intuitively sound,there is no theoretical basis or empirical evi-dence for such an argument.Therefore,it is crucial to study under what conditions the bid compensation is effective,and how much compensation is adequate with respect to different bidding situa-tions.This paper focuses on theoretically studying the impacts of bid compensation and tries to develop appropriate compensation strategies for projects with a costly bid preparation.Game theory will be applied to analyze the behavioral dynamics between com-peting bidders.Based on the game theoretic analysis and numeric trials,a bid compensation model is developed.The model pro-vides a quantitative framework,as well as qualitative implica-tions,on bid compensation strategies.Research Methodology:Game TheoryGame theory can be defined as “the study of mathematical models of conflict and cooperation between intelligent rational decision-makers”(Myerson 1991).Among economic theories,game theory has been successfully applied to many important issues such as negotiations,finance,and imperfect markets.Game theory has also been applied to construction management in two areas.Ho (2001)applied game theory to analyze the information asymme-try problem during the procurement of a BOT project and its1Assistant Professor,Dept.of Civil Engineering,National Taiwan Univ.,Taipei 10617,Taiwan.E-mail:spingho@.twNote.Discussion open until July 1,2005.Separate discussions must be submitted for individual papers.To extend the closing date by one month,a written request must be filed with the ASCE Managing Editor.The manuscript for this paper was submitted for review and possible publication on March 5,2003;approved on March 1,2004.This paper is part of the Journal of Construction Engineering and Management ,V ol.131,No.2,February 1,2005.©ASCE,ISSN 0733-9364/2005/2-151–159/$25.00.D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y N A N J I N G U N I VE R S I T Y OF o n 01/06/14. C o p y r i g h t A S C E . F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .implication in project financing and government policy.Ho and Liu (2004)develop a game theoretic model for analyzing the behavioral dynamics of builders and owners in construction claims.In competitive bidding,the strategic interactions among competing bidders and that between bidders and owners are com-mon,and thus game theory is a natural tool to analyze the prob-lem of concern.A well-known example of a game is the “prisoner’s dilemma”shown in Fig.1.Two suspects are arrested and held in separate cells.If both of them confess,then they will be sentenced to jail for 6years.If neither confesses,each will be sentenced for only 1year.However,if one of them confesses and the other does not,then the honest one will be rewarded by being released (in jail for 0year )and the other will be punished for 9years in jail.Note that in each cell,the first number represents player No.1’s payoff and the second one represents player No.2’s.The prisoner’s dilemma is called a “static game,”in which they act simultaneously;i.e.,each player does not know the other player’s decision before the player makes the decision.If the payoff matrix shown in Fig.1is known to all players,then the payoff matrix is a “common knowledge”to all players and this game is called a game of “complete information.”Note that the players of a game are assumed to be rational;i.e.,to maximize their payoffs.To answer what each prisoner will play/behave in this game,we will introduce the concept of “Nash equilibrium ,”one of the most important concepts in game theory.Nash equilibrium is a set of actions that will be chosen by each player.In a Nash equilib-rium,each player’s strategy should be the best response to the other player’s strategy,and no player wants to deviate from the equilibrium solution.Thus,the equilibrium or solution is “strate-gically stable”or “self-enforcing”(Gibbons 1992).Conversely,a nonequilibrium solution is not stable since at least one of the players can be better off by deviating from the nonequilibrium solution.In the prisoner’s dilemma,only the (confess,confess )solution where both players choose to confess,satisfies the stabil-ity test or requirement of Nash equilibrium.Note that although the (not confess,not confess )solution seems better off for both players compared to Nash equilibrium;however,this solution is unstable since either player can obtain extra benefit by deviating from this solution.Interested readers can refer to Gibbons (1992),Fudenberg and Tirole (1992),and Myerson (1991).Bid Compensation ModelIn this section,the bid compensation model is developed on the basis of game theoretic analysis.The model could help the ownerform bid compensation strategies under various competition situ-ations and project characteristics.Illustrative examples with nu-merical results are given when necessary to show how the model can be used in various scenarios.Assumptions and Model SetupTo perform a game theoretic study,it is critical to make necessary simplifications so that one can focus on the issues of concern and obtain insightful results.Then,the setup of a model will follow.The assumptions made in this model are summarized as follows.Note that these assumptions can be relaxed in future studies for more general purposes.1.Average bidders:The bidders are equally good,in terms oftheir technical and managerial capabilities.Since the design–build and BOT focus on quality issues,the prequalification process imposed during procurement reduces the variation of the quality of bidders.As a result,it is not unreasonable to make the “average bidders”assumption.plete information:If all players consider each other tobe an average bidder as suggested in the first assumption,it is natural to assume that the payoffs of each player in each potential solution are known to all players.3.Bid compensation for the second best bidder:Since DBIA’s(1996b )manual,document number 103,suggests that “the stipend is paid only to the most highly ranked unsuccessful offerors to prevent proposals being submitted simply to ob-tain a stipend,”we shall assume that the bid compensation will be offered to the second best bidder.4.Two levels of efforts:It is assumed that there are two levelsof efforts in preparing a proposal,high and average,denoted by H and A ,respectively.The effort A is defined as the level of effort that does not incur extra cost to improve quality.Contrarily,the effort H is defined as the level of effort that will incur extra cost,denoted as E ,to improve the quality of a proposal,where the improvement is detectable by an effec-tive proposal evaluation system.Typically,the standard of quality would be transformed to the evaluation criteria and their respective weights specified in the Request for Pro-posal.5.Fixed amount of bid compensation,S :The fixed amount canbe expressed by a certain percentage of the average profit,denoted as P ,assumed during the procurement by an average bidder.6.Absorption of extra cost,E :For convenience,it is assumedthat E will not be included in the bid price so that the high effort bidder will win the contract under the price–quality competition,such as best-value approach.This assumption simplifies the tradeoff between quality improvement and bid price increase.Two-Bidder GameIn this game,there are only two qualified bidders.The possible payoffs for each bidder in the game are shown in a normal form in Fig.2.If both bidders choose “H ,”denoted by ͑H ,H ͒,both bidders will have a 50%probability of wining the contract,and at the same time,have another 50%probability of losing the con-tract but being rewarded with the bid compensation,S .As a re-sult,the expected payoffs for the bidders in ͑H ,H ͒solution are ͑S /2+P /2−E ,S /2+P /2−E ͒.Note that the computation of the expected payoff is based on the assumption of the average bidder.Similarly,if the bidders choose ͑A ,A ͒,the expected payoffswillFig.1.Prisoner’s dilemmaD o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y N A N J I N G U N I VE R S I T Y OF o n 01/06/14. C o p y r i g h t A S C E . F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .be ͑S /2+P /2,S /2+P /2͒.If the bidders choose ͑H ,A ͒,bidder No.1will have a 100%probability of winning the contract,and thus the expected payoffs are ͑P −E ,S ͒.Similarly,if the bidders choose ͑A ,H ͒,the expected payoffs will be ͑S ,P −E ͒.Payoffs of an n -bidder game can be obtained by the same reasoning.Nash EquilibriumSince the payoffs in each equilibrium are expressed as functions of S ,P ,and E ,instead of a particular number,the model will focus on the conditions for each possible Nash equilibrium of the game.Here,the approach to solving for Nash equilibrium is to find conditions that ensure the stability or self-enforcing require-ment of Nash equilibrium.This technique will be applied throughout this paper.First,check the payoffs of ͑H ,H ͒solution.For bidder No.1or 2not to deviate from this solution,we must haveS /2+P /2−E ϾS →S ϽP −2E͑1͒Therefore,condition (1)guarantees ͑H ,H ͒to be a Nash equilib-rium.Second,check the payoffs of ͑A ,A ͒solution.For bidder No.1or 2not to deviate from ͑A ,A ͒,condition (2)must be satisfiedS /2+P /2ϾP −E →S ϾP −2E͑2͒Thus,condition (2)guarantees ͑A ,A ͒to be a Nash equilibrium.Note that the condition “S =P −2E ”will be ignored since the con-dition can become (1)or (2)by adding or subtracting an infinitely small positive number.Thus,since S must satisfy either condition (1)or condition (2),either ͑H ,H ͒or ͑A ,A ͒must be a unique Nash equilibrium.Third,check the payoffs of ͑H ,A ͒solution.For bid-der No.1not to deviate from H to A ,we must have P −E ϾS /2+P /2;i.e.,S ϽP −2E .For bidder No.2not to deviate from A to H ,we must have S ϾS /2+P /2−E ;i.e.,S ϾP −2E .Since S cannot be greater than and less than P −2E at the same time,͑H ,A ͒solution cannot exist.Similarly,͑A ,H ͒solution cannot exist either.This also confirms the previous conclusion that either ͑H ,H ͒or ͑A ,A ͒must be a unique Nash equilibrium.Impacts of Bid CompensationBid compensation is designed to serve as an incentive to induce bidders to make high effort.Therefore,the concerns of bid com-pensation strategy should focus on whether S can induce high effort and how effective it is.According to the equilibrium solu-tions,the bid compensation decision should depend on the mag-nitude of P −2E or the relative magnitude of E compared to P .If E is relatively small such that P Ͼ2E ,then P −2E will be positive and condition (1)will be satisfied even when S =0.This means that bid compensation is not an incentive for high effort when the extra cost of high effort is relatively low.Moreover,surprisingly,S can be damaging when S is high enough such that S ϾP −2E .On the other hand,if E is relatively large so that P −2E is negative,then condition (2)will always be satisfied since S can-not be negative.In this case,͑A ,A ͒will be a unique Nash equi-librium.In other words,when E is relatively large,it is not in the bidder’s interest to incur extra cost for improving the quality of proposal,and therefore,S cannot provide any incentives for high effort.To summarize,when E is relatively low,it is in the bidder’s interest to make high effort even if there is no bid compensation.When E is relatively high,the bidder will be better off by making average effort.In other words,bid compensation cannot promote extra effort in a two-bidder game,and ironically,bid compensa-tion may discourage high effort if the compensation is too much.Thus,in the two-bidder procurement,the owner should not use bid compensation as an incentive to induce high effort.Three-Bidder GameNash EquilibriumFig.3shows all the combinations of actions and their respective payoffs in a three-bidder game.Similar to the two-bidder game,here the Nash equilibrium can be solved by ensuring the stability of the solution.For equilibrium ͑H ,H ,H ͒,condition (3)must be satisfied for stability requirementS /3+P /3−E Ͼ0→S Ͼ3E −P͑3͒For equilibrium ͑A ,A ,A ͒,condition (4)must be satisfied so that no one has any incentives to choose HS /3+P /3ϾP −E →S Ͼ2P −3E͑4͒In a three-bidder game,it is possible that S will satisfy conditions (3)and (4)at the same time.This is different from the two-bidder game,where S can only satisfy either condition (1)or (2).Thus,there will be two pure strategy Nash equilibria when S satisfies conditions (3)and (4).However,since the payoff of ͑A ,A ,A ͒,S /3+P /3,is greater than the payoff of ͑H ,H ,H ͒,S /3+P /3−E ,for all bidders,the bidder will choose ͑A ,A ,A ͒eventually,pro-vided that a consensus between bidders of making effort A can be reached.The process of reaching such consensus is called “cheap talk,”where the agreement is beneficial to all players,and no player will want to deviate from such an agreement.In the design–build or BOT procurement,it is reasonable to believe that cheap talk can occur.Therefore,as long as condition (4)is satis-fied,͑A ,A ,A ͒will be a unique Nash equilibrium.An important implication is that the cheap talk condition must not be satisfied for any equilibrium solution other than ͑A ,A ,A ͒.In other words,condition (5)must be satisfied for all equilibrium solution except ͑A ,A ,A͒Fig.2.Two-biddergameFig.3.Three-bidder gameD o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y N A N J I N G U N I VE R S I T Y OF o n 01/06/14. C o p y r i g h t A S C E . F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .S Ͻ2P −3E ͑5͒Following this result,for ͑H ,H ,H ͒to be unique,conditions (3)and (5)must be satisfied;i.e.,we must have3E −P ϽS Ͻ2P −3E͑6͒Note that by definition S is a non-negative number;thus,if one cannot find a non-negative number to satisfy the equilibrium con-dition,then the respective equilibrium does not exist and the equi-librium condition will be marked as “N/A”in the illustrative fig-ures and tables.Next,check the solution where two bidders make high efforts and one bidder makes average effort,e.g.,͑H ,H ,A ͒.The ex-pected payoffs for ͑H ,H ,A ͒are ͑S /2+P /2−E ,S /2+P /2−E ,0͒.For ͑H ,H ,A ͒to be a Nash equilibrium,S /3+P /3−E Ͻ0must be satisfied so that the bidder with average effort will not deviate from A to H ,S /2+P /2−E ϾS /2must be satisfied so that the bidder with high effort will not deviate from H to A ,and condi-tion (5)must be satisfied as argued previously.The three condi-tions can be rewritten asS Ͻmin ͓3E −P ,2P −3E ͔andP −2E Ͼ0͑7͒Note that because of the average bidder assumption,if ͑H ,H ,A ͒is a Nash equilibrium,then ͑H ,A ,H ͒and ͑A ,H ,H ͒will also be the Nash equilibria.The three Nash equilibria will constitute a so-called mixed strategy Nash equilibrium,denoted by 2H +1A ,where each bidder randomizes actions between H and A with certain probabilities.The concept of mixed strategy Nash equilib-rium shall be explained in more detail in next section.Similarly,we can obtain the requirements for solution 1H +2A ,condition (5)and S /2+P /2−E ϽS /2must be satisfied.The requirements can be reorganized asS Ͻ2P −3EandP −2E Ͻ0͑8͒Note that the conflicting relationship between “P −2E Ͼ0”in condition (7)and “P −2E Ͻ0”in condition (8)seems to show that the two types of Nash equilibria are exclusive.Nevertheless,the only difference between 2H +1A and 1H +2A is that the bidder in 2H +1A equilibrium has a higher probability of playing H ,whereas the bidder in 1H +2A also mixes actions H and A but with lower probability of playing H .From this perspective,the difference between 2H +1A and 1H +2A is not very distinctive.In other words,one should not consider,for example,2H +1A ,to be two bidders playing H and one bidder playing A ;instead,one should consider each bidder to be playing H with higher probabil-ity.Similarly,1H +2A means that the bidder has a lower probabil-ity of playing H ,compared to 2H +1A .Illustrative Example:Effectiveness of Bid Compensation The equilibrium conditions for a three-bidder game is numerically illustrated and shown in Table 1,where P is arbitrarily assumed as 10%for numerical computation purposes and E varies to rep-resent different costs for higher efforts.The “*”in Table 1indi-cates that the zero compensation is the best strategy;i.e.,bid compensation is ineffective in terms of stimulating extra effort.According to the numerical results,Table 1shows that bid com-pensation can promote higher effort only when E is within the range of P /3ϽE ϽP /2,where zero compensation is not neces-sarily the best strategy.The question is that whether it is benefi-cial to the owner by incurring the cost of bid compensation when P /3ϽE ϽP /2.The answer to this question lies in the concept and definition of the mix strategy Nash equilibrium,2H +1A ,as explained previously.Since 2H +1A indicates that each bidderwill play H with significantly higher probability,2H +1A may already be good enough,knowing that we only need one bidder out of three to actually play H .We shall elaborate on this concept later in a more general setting.As a result,if the 2H +1A equilib-rium is good enough,the use of bid compensation in a three-bidder game will not be recommended.Four-Bidder Game and n-Bidder GameNash Equilibrium of Four-Bidder GameThe equilibrium of the four-bidder procurement can also be ob-tained.As the number of bidders increases,the number of poten-tial equilibria increases as well.Due to the length limitation,we shall only show the major equilibria and their conditions,which are derived following the same technique applied previously.The condition for pure strategy equilibrium 4H ,is4E −P ϽS Ͻ3P −4E͑9͒The condition for another pure strategy equilibrium,4A ,isS Ͼ3P −4E͑10͒Other potential equilibria are mainly mixed strategies,such as 3H +1A ,2H +2A ,and 1H +3A ,where the numeric number asso-ciated with H or A represents the number of bidders with effort H or A in a equilibrium.The condition for the 3H +1A equilibrium is3E −P ϽS Ͻmin ͓4E −P ,3P −4E ͔͑11͒For the 2H +2A equilibrium the condition is6E −3P ϽS Ͻmin ͓3E −P ,3P −4E ͔͑12͒The condition for the 1H +3A equilibrium isS Ͻmin ͓6E −3P ,3P −4E ͔͑13͒Illustrative Example of Four-Bidder GameTable 2numerically illustrates the impacts of bid compensation on the four-bidder procurement under different relative magni-tudes of E .When E is very small,bid compensation is not needed for promoting effort H .However,when E grows gradually,bid compensation becomes more effective.As E grows to a larger magnitude,greater than P /2,the 4H equilibrium would become impossible,no matter how large S is.In fact,if S is too large,bidders will be encouraged to take effort A .When E is extremely large,e.g.,E Ͼ0.6P ,the best strategy is to set S =0.The “*”in Table 2also indicates the cases that bid compensation is ineffec-Table pensation Impacts on a Three-Bidder GameEquilibriumE ;P =10%3H 2H +1A 1H +2A 3A E ϽP /3e.g.,E =2%S Ͻ14%*N/A N/N 14%ϽS P /3ϽE ϽP /2e.g.,E =4%2%ϽS Ͻ8%S Ͻ2%N/A 8%ϽS P /2ϽE Ͻ͑2/3͒P e.g.,E =5.5%N/AN/AS Ͻ3.5%*3.5%ϽS͑2/3͒P ϽEe.g.,E =7%N/A N/A N/A Always*Note:*denotes that zero compensation is the best strategy;and N/A =the respective equilibrium does not exist.D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y N A N J I N G U N I VE R S I T Y OF o n 01/06/14. C o p y r i g h t A S C E . F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .tive.To conclude,in a four-bidder procurement,bid compensation is not effective when E is relatively small or large.Again,similar to the three-bidder game,when bid compensation becomes more effective,it does not mean that offering bid compensation is the best strategy,since more variables need to be considered.Further analysis shall be performed later.Nash Equilibrium of n -Bidder GameIt is desirable to generalize our model to the n -bidder game,al-though only very limited qualified bidders will be involved in most design–build or BOT procurements,since for other project delivery methods it is possible to have many bidders.Interested readers can follow the numerical illustrations for three-and four-bidder games to obtain the numerical solutions of n -bidder game.Here,only analytical equilibrium solutions will be solved.For “nA ”to be the Nash equilibrium,we must have P −E ϽS /n +P /n for bidder A not to deviate.In other words,condition (14)must be satisfiedS Ͼ͑n −1͒P −nE͑14͒Note that condition (14)can be rewritten as S Ͼn ͑P −E ͒−P ,which implies that it is not likely for nA to be the Nash equilib-rium when there are many bidders,unless E is very close to or larger than P .Similar to previous analysis,for “nH ”to be the equilibrium,we must have S /n +P /n −E Ͼ0for stability requirement,and condition (15)for excluding the possibility of cheap talk or nA equilibrium.The condition for the nH equilibrium can be reorga-nized as condition (16).S Ͻ͑n −1͒P −nE ͑15͒nE −P ϽS Ͻ͑n −1͒P −nE͑16͒Note that if E ϽP /n ,condition (16)will always be satisfied and nH will be a unique equilibrium even when S =0.In other words,nH will not be the Nash equilibrium when there are many bidders,unless E is extremely small,i.e.,E ϽP /n .For “aH +͑n −a ͒A ,where 2Ͻa Ͻn ”to be the equilibrium so-lution,we must have S /a +P /a −E Ͼ0for bidder H not to devi-ate,S /͑a +1͒+P /͑a +1͒−E Ͻ0for bidder A not to deviate,and condition (15).These requirements can be rewritten asaE −P ϽS Ͻmin ͓͑a +1͒E −P ,͑n −1͒P −nE ͔͑17͒Similarly,for “2H +͑n −2͒A ,”the stability requirements for bidder H and A are S /͑n −1͒ϽS /2+P /2−E and S /3+P /3−E Ͻ0,re-spectively,and thus the equilibrium condition can be written as ͓͑n −1͒/͑n −3͔͒͑2E −P ͒ϽS Ͻmin ͓3E −P ,͑n −1͒P −nE ͔͑18͒For the “1H +͑n −1͒A ”equilibrium,we must haveS Ͻmin ͕͓͑n −1͒/͑n −3͔͒͑2E −P ͒,͑n −1͒P −nE ͖͑19͒An interesting question is:“What conditions would warrant that the only possible equilibrium of the game is either “1H +͑n −1͒A ”or nA ,no matter how large S is?”A logical response to the question is:when equilibria “aH +͑n −a ͒A ,where a Ͼ2”and equilibrium 2H +͑n −2͒A are not possible solutions.Thus,a suf-ficient condition here is that for any S Ͼ͓͑n −1͒/͑n −3͔͒͑2E −P ͒,the “S Ͻ͑n −1͒P −nE ”is not satisfied.This can be guaranteed if we have͑n −1͒P −nE Ͻ͓͑n −1͒/͑n −3͔͒͑2E −P ͒→E Ͼ͓͑n −1͒/͑n +1͔͒P͑20͒Conditions (19)and (20)show that when E is greater than ͓͑n −1͒/͑n +1͔͒P ,the only possible equilibrium of the game is either 1H +͑n −1͒A or nA ,no matter how large S is.Two important practical implications can be drawn from this finding.First,when n is small in a design–build contract,it is not unusual that E will be greater than ͓͑n −1͒/͑n +1͔͒P ,and in that case,bid compensa-tion cannot help to promote higher effort.For example,for a three-bidder procurement,bid compensation will not be effective when E is greater than ͑2/4͒P .Second,when the number of bidders increases,bid compensation will become more effective since it will be more unlikely that E is greater than ͓͑n −1͒/͑n +1͔͒P .The two implications confirm the previous analyses of two-,three-,and four-bidder game.After the game equilibria and the effective range of bid compensation have been solved,the next important task is to develop the bid compensation strategy with respect to various procurement situations.Table pensation Impacts on a Four-Bidder GameEquilibriumE ;P =10%4H 3H +1A 2H +2A 1H +3A 4A E ϽP /4e.g.,E =2%S Ͻ22%*N/A N/A N/A S Ͼ22%P /4ϽE ϽP /3e.g.,E =3%2%ϽS Ͻ18%S Ͻ2%N/A N/A S Ͼ18%P /3ϽE ϽP /2e.g.,E =4%6%ϽS Ͻ14%2%ϽS Ͻ6%S Ͻ2%N/A S Ͼ14%P /2ϽE Ͻ͑3/5͒P e.g.,E =5.5%N/A 6.5%ϽS Ͻ8%3%ϽS Ͻ6.5%S Ͻ3%S Ͼ8%͑3/5͒P ϽE Ͻ͑3/4͒P e.g.,E =6.5%N/AN/AN/AS Ͻ4%*S Ͼ4%͑3/4͒P ϽEe.g.,E =8%N/A N/A N/A N/AAlways*Note:*denotes that zero compensation is the best strategy;and N/A=respective equilibrium does not exist.D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y N A N J I N G U N I VE R S I T Y OF o n 01/06/14. C o p y r i g h t A S C E . F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .。
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。
毕业设计英文 翻译(原文)
编号:毕业设计(论文)外文翻译(原文)院(系):桂林电子科技大学专业:电子信息工程学生姓名: xx学号: xxxxxxxxxxxxx 指导教师单位:桂林电子科技大学姓名: xxxx职称: xx2014年x月xx日Timing on and off power supplyusesThe switching power supply products are widely used in industrial automation and control, military equipment, scientific equipment, LED lighting, industrial equipment,communications equipment,electrical equipment,instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerator, LCD monitor, LED lighting, communications equipment, audio-visual products, security, computer chassis, digital products and equipment and other fields.IntroductionWith the rapid development of power electronics technology, power electronics equipment and people's work, the relationship of life become increasingly close, and electronic equipment without reliable power, into the 1980s, computer power and the full realization of the switching power supply, the first to complete the computer Power new generation to enter the switching power supply in the 1990s have entered into a variety of electronic, electrical devices, program-controlled switchboards, communications, electronic testing equipment power control equipment, power supply, etc. have been widely used in switching power supply, but also to promote the rapid development of the switching power supply technology .Switching power supply is the use of modern power electronics technology to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply, switching power supply is generally controlled by pulse width modulation (PWM) ICs and switching devices (MOSFET, BJT) composition. Switching power supply and linear power compared to both the cost and growth with the increase of output power, but the two different growth rates. A power point, linear power supply costs, but higher than the switching power supply. With the development of power electronics technology and innovation, making the switching power supply technology to continue to innovate, the turning points of this cost is increasingly move to the low output power side, the switching power supply provides a broad space for development.The direction of its development is the high-frequency switching power supply, high frequency switching power supply miniaturization, and switching power supply into a wider range of application areas, especially in high-tech fields, and promote the miniaturization of high-tech products, light of. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.classificationModern switching power supply, there are two: one is the DC switching power supply; the other is the AC switching power supply. Introduces only DC switching power supply and its function is poor power quality of the original eco-power (coarse) - such as mains power or battery power, converted to meet the equipment requirements of high-quality DC voltage (Varitronix) . The core of the DC switching power supply DC / DC converter. DC switching power supply classification is dependent on the classification of DC / DC converter. In other words, the classification of the classification of the DC switching power supply and DC/DC converter is the classification of essentially the same, the DC / DC converter is basically a classification of the DC switching power supply.DC /DC converter between the input and output electrical isolation can be divided into two categories: one is isolated called isolated DC/DC converter; the other is not isolated as non-isolated DC / DC converter.Isolated DC / DC converter can also be classified by the number of active power devices. The single tube of DC / DC converter Forward (Forward), Feedback (Feedback) two. The double-barreled double-barreled DC/ DC converter Forward (Double Transistor Forward Converter), twin-tube feedback (Double Transistor Feedback Converter), Push-Pull (Push the Pull Converter) and half-bridge (Half-Bridge Converter) four. Four DC / DC converter is the full-bridge DC / DC converter (Full-Bridge Converter).Non-isolated DC / DC converter, according to the number of active power devices can be divided into single-tube, double pipe, and four three categories. Single tube to a total of six of the DC / DC converter, step-down (Buck) DC / DC converter, step-up (Boost) DC / DC converters, DC / DC converter, boost buck (Buck Boost) device of Cuk the DC / DC converter, the Zeta DC / DC converter and SEPIC, the DC / DC converter. DC / DC converters, the Buck and Boost type DC / DC converter is the basic buck-boost of Cuk, Zeta, SEPIC, type DC / DC converter is derived from a single tube in this six. The twin-tube cascaded double-barreled boost (buck-boost) DC / DC converter DC / DC converter. Four DC / DC converter is used, the full-bridge DC / DC converter (Full-Bridge Converter).Isolated DC / DC converter input and output electrical isolation is usually transformer to achieve the function of the transformer has a transformer, so conducive to the expansion of the converter output range of applications, but also easy to achieve different voltage output , or a variety of the same voltage output.Power switch voltage and current rating, the converter's output power is usually proportional to the number of switch. The more the number of switch, the greater the output power of the DC / DC converter, four type than the two output power is twice as large,single-tube output power of only four 1/4.A combination of non-isolated converters and isolated converters can be a single converter does not have their own characteristics. Energy transmission points, one-way transmission and two-way transmission of two DC / DC converter. DC / DC converter with bi-directional transmission function, either side of the transmission power from the power of lateral load power from the load-lateral side of the transmission power.DC / DC converter can be divided into self-excited and separately controlled. With the positive feedback signal converter to switch to self-sustaining periodic switching converter, called self-excited converter, such as the the Luo Yeer (Royer,) converter is a typical push-pull self-oscillating converter. Controlled DC / DC converter switching device control signal is generated by specialized external control circuit.the switching power supply.People in the field of switching power supply technology side of the development of power electronic devices, while the development of the switching inverter technology, the two promote each other to promote the switching power supply annual growth rate of more than two digits toward the light, small, thin, low-noise, high reliability, the direction of development of anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, AC / AC DC / AC, such as inverters, DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardization, and has been recognized by the user, but AC / DC modular, its own characteristics make the modular process, encounter more complex technology and manufacturing process. Hereinafter to illustrate the structure and characteristics of the two types of switching power supply.Self-excited: no external signal source can be self-oscillation, completely self-excited to see it as feedback oscillation circuit of a transformer.Separate excitation: entirely dependent on external sustain oscillations, excited used widely in practical applications. According to the excitation signal structure classification; can be divided into pulse-width-modulated and pulse amplitude modulated two pulse width modulated control the width of the signal is frequency, pulse amplitude modulation control signal amplitude between the same effect are the oscillation frequency to maintain within a certain range to achieve the effect of voltage stability. The winding of the transformer can generally be divided into three types, one group is involved in the oscillation of the primary winding, a group of sustained oscillations in the feedback winding, there is a group of load winding. Such as Shanghai is used in household appliances art technological production of switching power supply, 220V AC bridge rectifier, changing to about 300V DC filter added tothe collector of the switch into the transformer for high frequency oscillation, the feedback winding feedback to the base to maintain the circuit oscillating load winding induction signal, the DC voltage by the rectifier, filter, regulator to provide power to the load. Load winding to provide power at the same time, take up the ability to voltage stability, the principle is the voltage output circuit connected to a voltage sampling device to monitor the output voltage changes, and timely feedback to the oscillator circuit to adjust the oscillation frequency, so as to achieve stable voltage purposes, in order to avoid the interference of the circuit, the feedback voltage back to the oscillator circuit with optocoupler isolation.technology developmentsThe high-frequency switching power supply is the direction of its development, high-frequency switching power supply miniaturization, and switching power supply into the broader field of application, especially in high-tech fields, and promote the development and advancement of the switching power supply, an annual more than two-digit growth rate toward the light, small, thin, low noise, high reliability, the direction of the anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, the DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardized, and has been recognized by the user, but modular AC / DC, because of its own characteristics makes the modular process, encounter more complex technology and manufacturing process. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.The switching power supply applications in power electronic devices as diodes, IGBT and MOSFET.SCR switching power supply input rectifier circuit and soft start circuit, a small amount of applications, the GTR drive difficult, low switching frequency, gradually replace the IGBT and MOSFET.Direction of development of the switching power supply is a high-frequency, high reliability, low power, low noise, jamming and modular. Small, thin, and the key technology is the high frequency switching power supply light, so foreign major switching power supply manufacturers have committed to synchronize the development of new intelligent components, in particular, is to improve the secondary rectifier loss, and the power of iron Oxygen materials to increase scientific and technological innovation in order to improve the magnetic properties of high frequency and large magnetic flux density (Bs), and capacitor miniaturization is a key technology. SMT technology allows the switching power supply has made considerable progress, the arrangement of the components in the circuit board on bothsides, to ensure that the light of the switching power supply, a small, thin. High-frequency switching power supply is bound to the traditional PWM switching technology innovation, realization of ZVS, ZCS soft-switching technology has become the mainstream technology of the switching power supply, and a substantial increase in the efficiency of the switching power supply. Indicators for high reliability, switching power supply manufacturers in the United States by reducing the operating current, reducing the junction temperature and other measures to reduce the stress of the device, greatly improve the reliability of products.Modularity is the overall trend of switching power supply, distributed power systems can be composed of modular power supply, can be designed to N +1 redundant power system, and the parallel capacity expansion. For this shortcoming of the switching power supply running noise, separate the pursuit of high frequency noise will also increase, while the use of part of the resonant converter circuit technology to achieve high frequency, in theory, but also reduce noise, but some The practical application of the resonant converter technology, there are still technical problems, it is still a lot of work in this field, so that the technology to be practical.Power electronics technology innovation, switching power supply industry has broad prospects for development. To accelerate the pace of development of the switching power supply industry in China, it must take the road of technological innovation, out of joint production and research development path with Chinese characteristics and contribute to the rapid development of China's national economy.Developments and trends of the switching power supply1955 U.S. Royer (Roger) invented the self-oscillating push-pull transistor single-transformer DC-DC converter is the beginning of the high-frequency conversion control circuit 1957 check race Jen, Sen, invented a self-oscillating push-pull dual transformers, 1964, U.S. scientists canceled frequency transformer in series the idea of switching power supply, the power supply to the size and weight of the decline in a fundamental way. 1969 increased due to the pressure of the high-power silicon transistor, diode reverse recovery time shortened and other components to improve, and finally made a 25-kHz switching power supply.At present, the switching power supply to the small, lightweight and high efficiency characteristics are widely used in a variety of computer-oriented terminal equipment, communications equipment, etc. Almost all electronic equipment is indispensable for a rapid development of today's electronic information industry power mode. Bipolar transistor made of 100kHz, 500kHz power MOS-FET made, though already the practical switching power supply is currently available on the market, but its frequency to be further improved. Toimprove the switching frequency, it is necessary to reduce the switching losses, and to reduce the switching losses, the need for high-speed switch components. However, the switching speed will be affected by the distribution of the charge stored in the inductance and capacitance, or diode circuit to produce a surge or noise. This will not only affect the surrounding electronic equipment, but also greatly reduce the reliability of the power supply itself. Which, in order to prevent the switching Kai - closed the voltage surge, RC or LC buffers can be used, and the current surge can be caused by the diode stored charge of amorphous and other core made of magnetic buffer . However, the high frequency more than 1MHz, the resonant circuit to make the switch on the voltage or current through the switch was a sine wave, which can reduce switching losses, but also to control the occurrence of surges. This switch is called the resonant switch. Of this switching power supply is active, you can, in theory, because in this way do not need to greatly improve the switching speed of the switching losses reduced to zero, and the noise is expected to become one of the high-frequency switching power supply The main ways. At present, many countries in the world are committed to several trillion Hz converter utility.the principle of IntroductionThe switching power supply of the process is quite easy to understand, linear power supplies, power transistors operating in the linear mode and linear power, the PWM switching power supply to the power transistor turns on and off state, in both states, on the power transistor V - security product is very small (conduction, low voltage, large current; shutdown, voltage, current) V oltammetric product / power device is power semiconductor devices on the loss.Compared with the linear power supply, the PWM switching power supply more efficient process is achieved by "chopping", that is cut into the amplitude of the input DC voltage equal to the input voltage amplitude of the pulse voltage. The pulse duty cycle is adjusted by the switching power supply controller. Once the input voltage is cut into the AC square wave, its amplitude through the transformer to raise or lower. Number of groups of output voltage can be increased by increasing the number of primary and secondary windings of the transformer. After the last AC waveform after the rectifier filter the DC output voltage.The main purpose of the controller is to maintain the stability of the output voltage, the course of their work is very similar to the linear form of the controller. That is the function blocks of the controller, the voltage reference and error amplifier can be designed the same as the linear regulator. Their difference lies in the error amplifier output (error voltage) in the drive before the power tube to go through a voltage / pulse-width conversion unit.Switching power supply There are two main ways of working: Forward transformand boost transformation. Although they are all part of the layout difference is small, but the course of their work vary greatly, have advantages in specific applications.the circuit schematicThe so-called switching power supply, as the name implies, is a door, a door power through a closed power to stop by, then what is the door, the switching power supply using SCR, some switch, these two component performance is similar, are relying on the base switch control pole (SCR), coupled with the pulse signal to complete the on and off, the pulse signal is half attentive to control the pole voltage increases, the switch or transistor conduction, the filter output voltage of 300V, 220V rectifier conduction, transmitted through the switching transformer secondary through the transformer to the voltage increase or decrease for each circuit work. Oscillation pulse of negative semi-attentive to the power regulator, base, or SCR control voltage lower than the original set voltage power regulator cut-off, 300V power is off, switch the transformer secondary no voltage, then each circuit The required operating voltage, depends on this secondary road rectifier filter capacitor discharge to maintain. Repeat the process until the next pulse cycle is a half weeks when the signal arrival. This switch transformer is called the high-frequency transformer, because the operating frequency is higher than the 50HZ low frequency. Then promote the pulse of the switch or SCR, which requires the oscillator circuit, we know, the transistor has a characteristic, is the base-emitter voltage is 0.65-0.7V is the zoom state, 0.7V These are the saturated hydraulic conductivity state-0.1V-0.3V in the oscillatory state, then the operating point after a good tune, to rely on the deep negative feedback to generate a negative pressure, so that the oscillating tube onset, the frequency of the oscillating tube capacitor charging and discharging of the length of time from the base to determine the oscillation frequency of the output pulse amplitude, and vice versa on the small, which determines the size of the output voltage of the power regulator. Transformer secondary output voltage regulator, usually switching transformer, single around a set of coils, the voltage at its upper end, as the reference voltage after the rectifier filter, then through the optocoupler, this benchmark voltage return to the base of the oscillating tube pole to adjust the level of the oscillation frequency, if the transformer secondary voltage is increased, the sampling coil output voltage increases, the positive feedback voltage obtained through the optocoupler is also increased, this voltage is applied oscillating tube base, so that oscillation frequency is reduced, played a stable secondary output voltage stability, too small do not have to go into detail, nor it is necessary to understand the fine, such a high-power voltage transformer by switching transmission, separated and after the class returned by sampling the voltage from the opto-coupler pass separated after class, so before the mains voltage, and after the classseparation, which is called cold plate, it is safe, transformers before power is independent, which is called switching power supply.the DC / DC conversionDC / DC converter is a fixed DC voltage transformation into a variable DC voltage, also known as the DC chopper. There are two ways of working chopper, one Ts constant pulse width modulation mode, change the ton (General), the second is the frequency modulation, the same ton to change the Ts, (easy to produce interference). Circuit by the following categories:Buck circuit - the step-down chopper, the average output voltage U0 is less than the input voltage Ui, the same polarity.Boost Circuit - step-up chopper, the average output voltage switching power supply schematic U0 is greater than the input voltage Ui, the same polarity.Buck-Boost circuit - buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, the inductance transmission.Cuk circuit - a buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, capacitance transmission.The above-mentioned non-isolated circuit, the isolation circuit forward circuits, feedback circuit, the half-bridge circuit, the full bridge circuit, push-pull circuit. Today's soft-switching technology makes a qualitative leap in the DC / DC the U.S. VICOR company design and manufacture a variety of ECI soft-switching DC / DC converter, the maximum output power 300W, 600W, 800W, etc., the corresponding power density (6.2 , 10,17) W/cm3 efficiency (80-90)%. A the Japanese Nemic Lambda latest using soft-switching technology, high frequency switching power supply module RM Series, its switching frequency (200 to 300) kHz, power density has reached 27W/cm3 with synchronous rectifier (MOSFETs instead of Schottky diodes ), so that the whole circuit efficiency by up to 90%.AC / DC conversionAC / DC conversion will transform AC to DC, the power flow can be bi-directional power flow by the power flow to load known as the "rectification", referred to as "active inverter power flow returned by the load power. AC / DC converter input 50/60Hz AC due must be rectified, filtered, so the volume is relatively large filter capacitor is essential, while experiencing safety standards (such as UL, CCEE, etc.) and EMC Directive restrictions (such as IEC, FCC, CSA) in the AC input side must be added to the EMC filter and use meets the safety standards of the components, thus limiting the miniaturization of the volume of AC / DC power, In addition, due to internal frequency, high voltage, current switching, making the problem difficult to solve EMC also high demands on the internal high-density mountingcircuit design, for the same reason, the high voltage, high current switch makes power supply loss increases, limiting the AC / DC converter modular process, and therefore must be used to power system optimal design method to make it work efficiency to reach a certain level of satisfaction.AC / DC conversion circuit wiring can be divided into half-wave circuit, full-wave circuit. Press the power phase can be divided into single-phase three-phase, multiphase. Can be divided into a quadrant, two quadrant, three quadrants, four-quadrant circuit work quadrant.he selection of the switching power supplySwitching power supply input on the anti-jamming performance, compared to its circuit structure characteristics (multi-level series), the input disturbances, such as surge voltage is difficult to pass on the stability of the output voltage of the technical indicators and linear power have greater advantages, the output voltage stability up to (0.5)%. Switching power supply module as an integrated power electronic devices should be selected。
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粗甲醇精馏是个十分耗能的过程,所以控制甲醇的生产成本非常有必要。
尽管大量的节能精馏系统提出,但甲醇精馏仍有很大的节能潜力。
为了进一步降低甲醇精馏的能耗,现提出一种新型的多级五塔精馏过程,这本质上是对现有四塔精馏过程的一种改进。
四塔精馏由预精馏塔、加压塔、常压塔和回收塔组成。
新五塔精馏方案在原来四塔精馏方案中的加压塔后增加了一个中压塔。
通过这种方式,原加压塔和常压塔的负荷下降了约30%。
该五塔精馏方案实现了多效精馏过程包括预精馏塔、加压塔、中压塔、常压塔和回收塔之间的一种高效的热量循环利用。
稳态模拟过程结果表明在每两个换热器间的温差是适当的,能够有效的传热。
经济方面分析显示五塔精馏方案与四塔精馏方案相比可减少33.6%的能耗。
成本的显著节约说明该五塔精馏方案是经济可行、可以实现的。
关键字:甲醇;多级精馏;热量利用过程模拟;节能1 简介精馏,是在化工行业中应用最广泛的分离技术,约消耗的3%世界能源。
尽管该技术已经成熟和得到不断优化,但其仍是一个十分耗能的操作过程。
为了降低能源消耗,70年前首次引入了热量循环利用的概念。
热量循环利用的基本思想是物质之间的冷热交换。
到目前为止,各种热量循环利用精馏方案不断提出,最近的一篇学术文章中有详细描述。
今天,经济因素加上环境问题(如二氧化碳排放)正起着振兴蒸馏塔的热效率的作用。
甲醇生产过程中,精馏是标准的分离方法。
目前,相当多的甲醇生产厂家利用天然气生产合成气。
原始的低压甲醇生产过程是在甲醇合成反应器中添加催化剂,有种典型的两塔精馏系统采用的原料是含水和一些有机杂质的粗甲醇。
这种方案在文献中有广泛的报道。
自1970年代中期以来由于能源危机的急剧上升,甲醇生产技术的许可者和经营者集中越来越关注可以替代这种标准两塔精馏系统的方案。
到目前为止,提出许多了替代方案,其中鲁奇发明的两级三塔装置被广泛应用于工业生产。
这些替代方案中有种两塔精馏方案是将两个塔分别处于在不同的操作压力之下,这样处于高压的塔生产的产品可使处于较低压的塔生产的产品进行再沸。
几个新型的节能三塔方案在文献中已有涉及。
鲁奇的三塔甲醇精馏装置是由预精馏塔、加压塔和常压塔组成。
为了进一步降低废水中甲醇含量和杂醇油的损失,提出了一个改进方案,是在鲁奇的三塔后增加回收塔,目前被应用于用于大规模的甲醇生产厂家。
这个改进方案被称为四塔精馏系统,该装置是现有甲醇生产的必要装置。
它的工艺如图2所示。
这表明该四塔甲醇精馏装置存在节能的潜力。
稳态模拟过程结果表明,这种新型多级四塔甲醇精馏方案与传统的四塔工艺相比可以大大的降低能源需求。
2 四塔多级精馏方案的基本情况四塔装置如图2所示,原料粗甲醇通过预精馏塔C1,加压塔C2和常压塔C 4。
塔C1和C4的操作压力略高于大气压,而塔C2的操作压力为0.5-0.8 MPa。
塔C1作用是去除轻组分。
加热后的粗甲醇后进入塔C1后在顶部阶段和再沸器中产生的甲醇蒸汽已经除去了轻组分(如二甲醚、甲酸甲酯和丙酮)和溶解在粗甲醇中的杂质气体。
塔C1的底部产品经加压和加热后,送到塔C2,大约40-50%的甲醇成为塔顶产品或塔顶回流液。
塔C2的底部产品进入塔C4,剩余的甲醇变为过热蒸汽,而废水是流回底部。
中间沸腾杂质(主要是乙醇,但也有高级醇)在加料板下进行回流。
为了减少能耗,加压塔C2的过热蒸汽用于对常压塔C4底部进行加热。
一般来说,来自常压塔底部的废水中甲醇含量范围在0.01-0.1%,不符合废水的排放标准。
而且常压塔C4的回流液中还包括大量的甲醇。
常压塔C4大多数残留在底部的甲醇和回流液在回收塔C5中产生过热蒸汽。
杂醇进行回流,塔C5的底部废水符合排放标准。
与传统的两塔方案相比,四塔方案能节能30%。
然而四塔方案中仍存在如下的不足:1.预精馏塔C1底部温度低于常压塔C4底部温度。
塔C4使用加压塔C2的过热蒸汽作为热源,而塔C1使用0.5MPa蒸汽作为热源。
2.塔C2的能耗占总能耗的40%,而且塔再沸器的蒸汽消耗太大。
3.完全的分离是不可能的,因为常压塔C4和回收塔C5产生的废水中总会含有甲醇。
3 五塔多效精馏方案新型五塔多级甲醇精馏方案工艺流程如图3所示。
五塔和四塔方案两者之间的主要差异概括如下:1.在加压塔后添加一个中压塔C3,其操作压力控制在加压塔C2和常压塔C4之间。
2.精馏得到的甲醇产品以适当的比例分别作为塔C2、C3、C4和C5的过热蒸汽。
回收塔C5几乎成为一个提纯塔。
更重要的是,塔C4中没有回流液流出。
通过这种方式,甲醇含量增加,塔C4的底部温度温度降低。
因此,塔C2和C3产生的过热蒸汽可以分别对塔C3和C4的底部进行加热。
3.进入塔C5的原料中甲醇含量大大增加,通过增加塔的操作压力可以提高塔的顶部温度,从而影响塔C5和C1之间的热循环利用,即塔C5的顶部蒸汽可以作为塔C1的热源。
通过这种方式实现多效精馏,从而在很大程度上降低塔C2的热负荷。
因此,可以实现水电消耗的显著节约。
计算机技术的迅速发展和广泛应用于过程控制可以有效地处理更复杂的双效蒸馏过程。
因此,上述新流程的正常运行需要解决以下问题:1.加压塔C2、中压塔C3和回收塔C4要选择合适的操作压力,以便塔C2顶部和塔C3的底部之间、塔C3的顶部和塔C4的底部之间和塔C5的顶部和塔C1的底部之间有合适的温度差。
2.确定除预精馏塔C1之外每个塔顶部产生的甲醇产品所占比例,为了满足多效蒸馏的热循环利用的需求。
4 两个方案的稳态模拟模拟中粗甲醇的组成和参数如表1所示。
热源为0.5 MPa的饱和蒸汽。
空气冷凝器用作间壁冷凝。
冷却水作为冷却介质进入预精馏塔的双程间壁冷凝器冷却所有产品。
冷却水的入口、出口温度分别30°C和40°C。
甲醇产品纯度要求为99.99 %。
回收塔底部废水中甲醇含量不超过0.005 %。
四塔方案中常压塔底部废水的甲醇含量控制在0.01%以下。
而在五塔方案中不需要控制。
两个方案的模拟都使用商业软件Pro / II。
采用NRTL方程计算每一塔液相活度系数,除了使用软件Pro /II提供的特殊酒精程序包的回收塔。
根据采用鲁奇的三塔系统的甲醇工厂现场提供的相应数据,每一塔的理论塔板数确定。
每一塔的操作压力被认为是通过引用数据和在每个塔两面的再沸器和冷凝器设置适当的温度差而定。
压力降的计算,考虑到塔内部的类型如下:塔C1、C2、C1′、C2′、C3、C3′和C4采用填料塔;塔C4′采用规整填料在上层部分精流段,下半部分提馏段采用浮阀;塔C5和C5′,精馏段的上半部分采用规整填料、下半部分采用浮阀,提馏段采用浮阀。
每一个塔的结构,在精馏段和提馏段分别采用BX和250Y。
在预精馏塔有一个双程间壁冷凝器。
预精馏塔的换热器先将一部分气体冷凝到65°C,其余的部分蒸汽在冷凝器冷凝到40°C。
第二部分的气体流离开冷凝器送到洗涤塔。
回收塔的洗涤液送到预精馏塔,它作为萃取剂从预精馏塔加料板处加入。
这种分步冷却在双程冷凝器和洗涤塔只产生非常低的甲醇轻组分损失。
根据现场数据得出预精馏塔回流比大约是0.5-0.8,稳态模拟中为0.53。
其他列的回流比是通过使用Pro / II严格计算的。
此外,根据冷热流的能量水平提出一个合理的换热方案。
冷热流热交换采用逆流,最低温度差为15°C。
因为四塔方案是基于现有的甲醇工厂在处理能力、流程配置、操作条件等方面考虑的,四塔方案假定的成本等于2008年这类工厂的实际投资。
五塔方案假定的成本和四塔方案相差不大。
5 结果与讨论5.1能耗分析表2给出了物料平衡和表3总结了每个塔两个方案的操作条件和计算结果。
从表2和表3可以看出,四塔方案中纯甲醇产品基本上是由塔C2和C4生产的,塔C2和C4产量占总产量的比例分别为45.60%和53.39%。
两级精馏的热量总要求是49.688 兆瓦。
五塔方案中纯甲醇产品的任务是由塔C2、C3、C4和C5基于热循环利用的匹配要求而得,各塔产量占总产量的比例分别为26.62%、29.97%、35.53%和7.88%。
总热量需求降至32.982兆瓦。
五塔方案与四塔方案相比,能耗降低33.6%。
如果与传统的两塔方案相比,新的五塔方案能耗下降了53.5%。
相比之下,四塔方案与传统的两塔方案相比能耗减少30%。
此外,两个方案的纯甲醇产品质量能满足美国标准的“AA”级和废水中的甲醇含量低于0.005%,结果如表4所示。
四塔和五塔案然甲醇的回收率几乎相同,都达到了99.98%。
冷凝器和再沸器相同的指标是指冷凝器和再沸器的热量是循环利用的。
5.2每个塔操作条件和分离难度的变化两个方案的预精馏塔中冷凝器和再沸器参数保持不变。
为了满足要求的传热温差,与塔C2′相比塔C2的操作压力是增加了约70 kPa,因而,中间产品温度从132.1°C升到135.0°C。
因而塔C2中间产物的分离难度明显减少,两塔的回流比保持不变。
与塔C2相比,新添加的中压柱C3的操作压力降低到360 kPa 及其分离难度也降低了。
因为塔C2和C3理论塔板数是相同的,故回流比从R2 = 2.73减少到R3 = 2.30。
对于常压塔C4,回流比和分离难度均低于塔C4′,因为塔C4底部产品的甲醇含量不再需要控制,它高达28.28%。
随着塔C4底部产品中甲醇含量的增加,它带来另一个优点是底部温度的明显降低从107.8°C 降到82.1°C,为塔C2、C3和C4之间的多级精馏创造了非常适宜的的传热温差。
最明显的改变发生在回收塔。
四塔方案的主要任务是回收残留甲醇作为中间产物,杂醇进行回流,塔底部废水符合污水排放标准。
与四塔方案相比五塔方案中塔C5中原料的流量和甲醇含量大大增加,因此回收塔C5差不多就是个提纯塔。
因而与塔C5′相比塔C5的分离难度大大降低。
另一方面,为了在C5和C1间形成两级精馏,塔C5的操作压力增加到220 kPa,从而增加分离难度。
塔C5和C1之间的两级精馏主要依赖于塔C1的再沸器。
因此,当塔C5的流量一定时,回流比R5在一个很小的范围内波动。
仿真结果表明,R5等于4.73,与R5′相比减小30.4%。
因此,与塔C5′相比塔C5所需的理论塔板数从40增加了60。
得出的结论为塔C5分离难度略高于塔C5′。
5.3传热温差表6列出了这两个方案中每个塔两面的冷凝器和再沸器的温差。
从表6可以看出,五塔方案中每个冷凝器和再沸器的温差小于四塔方案。
但都高于20°C,足以满足传热的高要求,这证实了新工艺是可行的。
表7给出使用0.5 MPa饱和蒸汽作为热源的每个再沸器的温差异。
加压塔C2在最高操作压力下塔底部与0.5 MPa蒸汽有最小的温差,但仍有18.2°C。
与塔C2′的再沸器相比,塔C2两面的再沸器温差降低 2.1°C,但它仍然可以满足传热的需求。