写开题报告,文献综述,外文翻译,毕业论文的资料,途径

第一篇：写开题报告,文献综述,外文翻译,毕业论文的资料,途径

开题报告主要包括以下几个方面：

（一）论文名称

论文名称就是课题的名字

第一，名称要准确、规范。准确就是论文的名称要把论文研究的问题是什么，研究的对象是什么交待清楚，论文的名称一定要和研究的内容相一致，不能太大，也不能太小，要准确地把你研究的对象、问题概括出来。

第二，名称要简洁，不能太长。不管是论文或者课题，名称都不能太长，能不要的字就尽量不要，一般不要超过20个字。

（二）论文研究的目的、意义

研究的目的、意义也就是为什么要研究、研究它有什么价值。这一般可以先从现实需要方面去论述，指出现实当中存在这个问题，需要去研究，去解决，本论文的研究有什么实际作用，然后，再写论文的理论和学术价值。这些都要写得具体一点，有针对性一点，不能漫无边际地空喊口号。主要内容包括：⑴ 研究的有关背景(课题的提出)： 即根据什么、受什么启发而搞这项研究。⑵ 通过分析本地（校）的教育教学实际，指出为什么要研究该课题，研究的价值，要解决的问题。

（三）本论文国内外研究的历史和现状（文献综述）。

规范些应该有，如果是小课题可以省略。一般包括：掌握其研究的广度、深度、已取得的成果；寻找有待进一步研究的问题，从而确定本课题研究的平台(起点)、研究的特色或突破点。

（四）论文研究的指导思想

指导思想就是在宏观上应坚持什么方向，符合什么要求等，这个方向或要求可以是哲学、政治理论，也可以是政府的教育发展规划，也可以是有关研究问题的指导性意见等。

（五）论文写作的目标

论文写作的目标也就是课题最后要达到的具体目的,要解决哪些具体问题，也就是本论文研究要达到的预定目标：即本论文写作的目标定位，确定目标时要紧扣课题,用词要准确、精练、明了。

常见存在问题是：不写研究目标；目标扣题不紧；目标用词不准确； 目标定得过高, 对预定的目标没有进行研究或无法进行研究。

确定论文写作目标时，一方面要考虑课题本身的要求，另一方面要考率实际的工作条件与工作水平。

（六）论文的基本内容

研究内容要更具体、明确。并且一个目标可能要通过几方面的研究内容来实现，他们不一定是一一对应的关系。大家在确定研究内容的时候，往往考虑的不是很具体，写出来的研究内容特别笼统、模糊，把写作的目的、意义当作研究内容。基本内容一般包括：⑴对论文名称的界说。应尽可能明确三点：研究的对象、研究的问题、研究的方法。⑵本论文写作有关的理论、名词、术语、概念的界说。

（七）论文写作的方法

具体的写作方法可从下面选定： 观察法、调查法、实验法、经验总结法、个案法、比较研究法、文献资料法等。

（八）论文写作的步骤

论文写作的步骤，也就是论文写作在时间和顺序上的安排。论文写作的步骤要充分考虑研究内容的相互关系和难易程度，一般情况下，都是从基础问题开始，分阶段进行，每个阶段从什么时间开始，至什么时间结束都要有规定。课题研究的主要步骤和时间安排包括：整个研究拟分为哪几个阶段；各阶段的起止时间 文献综述怎么写

1)什么是文献综述? 文献综述是研究者在其提前阅读过某一主题的文献后，经过理解、整理、融会贯通，综合分析和评价而组成的一种不同于研究论文的文体。2)文献综述的写作要求

1、文献综述的格式

文献综述的格式与一般研究性论文的格式有所不同。这是因为研究性的论文注重研究的方法和结果，而文献综述介绍与主题有关的详细资料、动态、进展、展望以及对以上方面的评述。因此文献综述的格式相对多样，但总的来说，一般都包含以下四部分：即前言、主题、总结和参考文献。撰写文献综述时可按这四部分拟写提纲，再根据提纲进行撰写工作。前言，要用简明扼要的文字说明写作的目的、必要性、有关概念的定义，综述的范围，阐述有关问题的现状和动态，以及目前对主要问题争论的焦点等。前言一般200-300字为宜，不宜超过500字。

正文，是综述的重点，写法上没有固定的格式，只要能较好地表达综合的内容，作者可创造性采用诸多形式。正文主要包括论据和论证两个部分，通过提出问题、分析问题和解决问题，比较不同学者对同一问题的看法及其理论依据，进一步阐明问题的来龙去脉和作者自己的见解。当然，作者也可从问题发生的历史背景、目前现状、发展方向等提出文献的不同观点。正文部分可根据内容的多少可分为若干个小标题分别论述。小结，是结综述正文部分作扼要的总结，作者应对各种观点进行综合评价，提出自己的看法，指出存在的问题及今后发展的方向和展望。内容单纯的综述也可不写小结。参考文献，是综述的重要组成部分。一般参考文献的多少可体现作者阅读文献的广度和深度。对综述类论文参考文献的数量不同杂志有不同的要求，一般以30条以内为宜，以最近3-5年内的最新文献为主。

2、文献综述规定

1.为了使选题报告有较充分的依据，要求硕士研究生在论文开题之前作文献综述。

2.在文献综述时，研究生应系统地查阅与自己的研究方向有关的国内外文献。通常阅读文献不少于30篇，且文献搜集要客观全面

3.在文献综述中，研究生应说明自己研究方向的发展历史，前人的主要研究成果，存在的问题及发展趋势等。

4.文献综述要条理清晰，文字通顺简练。

5.资料运用恰当、合理。文献引用用方括号[ ]括起来置于引用词的右上角。

6.文献综述中要有自己的观点和见解。不能混淆作者与文献的观点。鼓励研究生多发现问题、多提出问题、并指出分析、解决问题的可能途径，针对性强。

7.文献综述不少于3000字。

3、注意事项 ⒈ 搜集文献应尽量全。掌握全面、大量的文献资料是写好综述的前提，否则，随便搜集一点资料就动手撰写是不可能写出好的综述。

⒉ 注意引用文献的代表性、可靠性和科学性。在搜集到的文献中可能出现观点雷同，有的文献在可靠性及科学性方面存在着差异，因此在引用文献时应注意选用代表性、可靠性和科学性较好的文献。

⒊ 引用文献要忠实文献内容。由于文献综述有作者自己的评论分析，因此在撰写时应分清作者的观点和文献的内容，不能篡改文献的内容。引用文献不过多。文献综述的作者引用间接文献的现象时有所见。如果综述作者从他人引用的参考文献转引过来，这些文献在他人引用时是否恰当，有无谬误，综述作者是不知道的，所以最好不要间接转引文献。⒋ 参考文献不能省略。有的科研论文可以将参考文献省略，但文献综述绝对不能省略，而且应是文中引用过的，能反映主题全貌的并且是作者直接阅读过的文献资料。

5.综述篇幅不可太长。杂志编辑部对综述的字数一般都有一定数量的约定。作者在初写综述时，往往不注意这点，造成虚话、空话较多，重点不突出。综述一般不宜超过4000字。综述并不是简单的文献罗列，综述一定有作者自己的综合和归纳。有的综述只是将文献罗列，看上去像流水帐，没有作者自己的综合与分析，使人看后感到重复、费解，材料与评述协调。3)学术论文参考文献的著录格式

1.专著： ［序号］作者.书名[M].版本(第1版不著录).出版地:出版者,出版年.起止页码.2.期刊: ［序号］作者.题名[J].刊名,年,卷(期):起止页码.3.会议论文集（或汇编）: ［序号］作者.题名[A].编者.论文集名[C].出版地:出版者,出版年.起止页码.4.学位论文: ［序号］作者.题名[D].学位授予地址：学位授予单位，年份.5.专利: ［序号］专利申请者.专利题名[P].专利国别（或地区）:专利号, 出版日期.6.科技报告: ［序号］著者.报告题名[R].编号，出版地：出版者，出版年.起止页码.7.标准: ［序号］ 标准编号，标准名称[S].颁布日期.8.报纸文章 : [序号] 作者.题名[N].报纸名，年-月-日（版次）.9.电子文献: ［序号］ 主要责任者.电子文献题名［电子文献及载体类型标识］.电子文献的出处或可获得地址，发表或更新日期/引用日期(任选).10.各种未定义类型的文献: ［序号］主要责任者.文献题名［Z］.出版地：出版者，出版年.您正浏览的文章《文献综述怎么写-文秘范文》由 个人简历 网:http://

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第二篇：超声波测距毕业论文中英文对照资料外文翻译文献

超声波测距毕业论文中英文对照资料外文翻译文献

超声波测距 中英文对照资料外文翻译 超声测距系统设计 原文出处：传感器文摘 布拉福德:1993年 第13页摘要：超声测距技术在工业现场、车辆导航、水声工程等领域都具有广泛的应用价值，目前已应用于物位测量、机器人自动导航以及空气中与水下的目标探测、识别、定位等场合。因此，深入研究超声的测距理论和方法具有重要的实践意义。为了进一步提高测距的精确度，满足工程人员对测量精度、测距量程和测距仪使用的要求，本文研制了一套基于单片机的便携式超声测距系统。关键词：超声波，测距仪，单片机

1、前言 随着科技的发展，人们生活水平的提高，城市发展建设加快，城市给排水系统也有较大发展，其状况不断改善。但是，由于历史原因合成时间住的许多不可预见因素，城市给排水系统，特别是排水系统往往落后于城市建设。因此，经常出现开挖已经建设好的建筑设施来改造排水系统的现象。城市污水给人们带来了困扰，因此箱涵的排污疏通对大城市给排水系统污水处理，人们生活舒适显得非常重要。而设计研制箱涵排水疏通移动机器人的自动控制系统，保证机器人在箱涵中自由排污疏通，是箱涵排污疏通机器人的设计研制的核心部分。控制系统核心部分就是超声波测距仪的研制。因此，设计好的超声波测距仪就显得非常重要了。

2、超声波测距原理2.1 压电式超声波发生器原理 毕业设计（论文）英文翻译 压电式超声波发生器实际上是利用压电晶体的谐振来工作的。超声波发生器内部结构，它有两个压电晶片和一个共振板。当它的两极外加脉冲信号，其频率等于压电晶片的固有振荡频率时，压电晶片将会发生共振，并带动共振板振动，便产生超声波。反之，如果两电极间未外加电压，当共振板接收到超声波 时，将压迫压电晶片作振动，将机械能转换为电信号，这时它就成为超声波接收器了。测量脉冲到达时间的传统方法是以拥有固定参数的接收信号开端为基础的。这个界限恰恰选于噪音水平之上，然而脉冲到达时间被定义为脉冲信号刚好超过界限的第一时刻。一个物体的脉冲强度很大程度上取决于这个物体的自然属性尺寸还有它与传感器的距离。进一步说，从脉冲起始点到刚好超过界限之间的时间段随着脉冲的强度而改变。结果，一种错误便出现了——两个拥有不同强度的脉冲在不同时间超过界限却在同一时间到达。强度较强的脉冲会比强度较弱的脉冲超过界限的时间早点，因此我们会认为强度较强的脉冲属于较近的物体。2.2 超声波测距原理 超声波发射器向某一方向发射超声波，在发射时刻的同时开始计时，超声波在空气中传播，途中碰到障碍物就立即返回来，超声波接收器收到反射波就立即停止计时。超声波在空气中的传播速度为 340m/s，根据计时器记录的时间 t，就可以计算出发射点距障碍物的距离s，即：s340t/

23、超声波测距系统的电路设计 系统的特点是利用单片机控制超声波的发射和对超声波自发射至接收往返时间的计时，单片机选用 C51，经济易用，且片内有 4K 的 ROM，便于编程。电路原理图如图 1 所示。‐1‐毕业设计（论文）英文翻译 图 1 电路原理图 ‐2‐ 毕业设计（论文）英文翻译3.1 40kHz 脉冲的产生与超声波发射 测距系统中的超声波传感器采用 UCM40 的压电陶瓷传感器，它的工作电压是40kHz 的脉冲信号，这由单片机执行下面程序来产生。puzel： mov 14h 12h；超声波发射持续 200mshere： cpl p1.0 ； 输出 40kHz 方波 nop ； nop ； nop ； djnz 14h，here； ret 前方测距电路的输入端接单片机 P1.0 端口，单片机执行上面的程序后，在 P1.0端口输出一个 40kHz 的脉冲信号，经过三极管 T 放大，驱动超声波发射头 UCM40T，发出 40kHz 的脉冲超声波，且持续发射 200ms。右侧和左侧测 距电路的输入端分别接 P1.1 和 P1.2 端口，工作原理与前方测距电路相同。3.2 超声波的接收与处理 接收头采用与发射头配对的 UCM40R，将超声波调制脉冲变为交变电压信号，经 IC2运算放大器 IC1A 和 IC1B 两极放大后加至 IC2。是带有锁 定环的音频译码集成块LM567，内部的压控振荡器的中心频率 f01/1.1R8C3，电容 C4 决定其锁定带宽。调节 R8 在发射的载频上，则 LM567 输入信号大于 25mV，输出端 8 脚由高电平跃变为低电平，作为中断请求信号，送至单片机处理.前方测距电路的输出端接单片机 INT0 端口，中断优先级最高，左、右测距电路的输出通过与门 IC3A 的输出接单片机 INT1 端口，同时单片机 P1.3 和 P1.4 接到 IC3A的输入端，中断源的识别由程序查询来处理，中断优先级为先右后左。部分源程序如下：receive1：push psw push acc clr ex1； 关外部中断 1 jnb p1.1right；P1.1 引脚为 0转至右测距电路中断服务程序 ‐3‐ 毕业设计（论文）英文翻译 jnb p1.2left；P1.2 引脚为 0转至左测距电路中断服务程序return： SETB EX1； 开外部中断 1 pop acc pop psw retiright：...； 右测距电路中断服务程序入口 ajmp returnleft：...； 左测距电路中断服务程序入口 ajmp return3.3 计算超声波传播时间 在启动发射电路的同时启动单片机内部的定时器 T0，利用定时器的计数功能记录超声波发射的时间和收到反射波的时间。当收到超声波反射波时，接收电路 输出端产生一个负跳变，在 INT0 或 INT1 端产生一个中断请求信号，单片机响应外部中断请求，执行外部中断服务子程序，读取时间差，计算距离。其部分源程序如下：RECEIVE0： PUSH PSW PUSH ACC CLR EX0 ； 关外部中断 0 MOV R7 TH0 ； 读取时间值 MOV R6 TL0 CLR C MOV A R6 SUBB A 0BBH； 计算时间差 MOV 31H A ； 存储结果 MOV A R7 SUBB A 3CH MOV 30H A SETB EX0 ； 开外部中断 0 POP ACC ‐4‐ 毕业设计（论文）英文翻译 POP PSW RETI对于一个平坦的目标，距离测量包括两个阶段:粗糙的测量和精细测量。第一步：脉冲的传送产生一种简单的超声波。第二步：根据公式改变回波放大器的获得量直到回拨被检测到。第三步：检测两种回波的振幅与过零时间。第四步：设置回波放大器的所得来规格输出，假定是 3 伏。通过脉冲的周期设置下一 个脉冲。根据第二部的数据设定时间窗。第五步：发射两串脉冲产生干扰波。测量过零时间与回波的振幅。如果逆向发生在回 波中，决定要不通过在低气压插入振幅。第六步：通过公式计算距离 y。

4、超声波测距系统的软件设计 软件分为两部分，主程序和中断服务程序。主程序完成初始化工作、各路超声波发射和接收顺序的控制。定时中断服务子程序完成三方向超声波的轮流发射，外部中断服务子程序主要完成时间值的读取、距离计算、结果的输出等工作。

5、结论 对所要求测量范围 30cm200cm 内的平面物体做了多次测量发现，其最大误差为0.5cm，且重复性好。可见基于单片机设计的超声波测距系统具有硬件结构简单、工作可靠、测量误差小等特点。因此，它不仅可用于移动机器人，还可用在其它检测系统中。思考：至于为什么接收不用晶体管做放大电路呢，因为放大倍数搞不好，集成放大电路，还带自动电平增益控制，放大倍数为 76dB，中心频率是 38k 到 40k，刚好是超声波传感器的谐振频率。‐5‐ 毕业设计（论文）英文翻译 参考文献1.Fox J.D.Khuri-Yakub B.T.and Kino G.S.quotHigh Frequency Acoustic WaveMeasurement in Airquot in Proceedings of IEEE 1983 Ultrasonic Symposium October 31-2November 1983 Atlanta GA pp.581-4.2.Martin Abreu J.M.Ceres R.and Freire T.quotUltrasonic Ranging: Envelope AnalysisGives Improved Accuracyquot Sensor Review Vol.12 No.1 1992 pp.17-21.3.Parrilla M.Anaya J.J.and Fritsch C.quotDigital Signal Processing Techniques for HighAccuracy Ultrasonic Range Measurementsquot IEEE Transactions: Instrumentation andMeasurement Vol.40 No.4 August 1991 pp.759-63.4.Canali C.Cicco G.D.Mortem B.Prudenziati M.and Taron A.quotA TemperatureCompensated Ultrasonic Sensor Operating in Air for Distance and ProximityMeasurementquot IEEE Transaction on Industry Electronics Vol.IE-29 No.4 1982 pp.336-41.‐6‐ 毕业设计（论文）英文翻译 Ultrasonic ranging system design Publicationtitle: Sensor Review.Bradford: 1993.Vol.13ABSTRACT：Ultrasonic ranging technology has wide using worth in many fields，such as the industriallocale，vehicle navigation and sonar engineering．Now it has been used in level measurement，self-guided autonomous vehicles fieldwork robots automotive navigation，air and underwater targetdetection，identification，location and so on．So there is an important practicing meaning to learn theranging theory and ways deeply.To improve the precision of the ultrasonic ranging system in hand，satisfy the request of the engineering personnel for the ranging precision，the bound and the usage，aportable ultrasonic ranging system based on the single chip processor was developed．Keywords：Ultrasound r，Ranging System，Single Chip Processor1.Introductive With the development of science and technology the improvement of peoplesstandard of living speeding up the development and construction of the city.urbandrainage system have greatly developed their situation is constantly improving.Howeverdue to historical reasons many unpredictable factors in the synthesis of her time the citydrainage system.In particular drainage system often lags behind urban construction.Therefore there are often good building excavation has been building facilities to upgradethe drainage system phenomenon.It brought to the city sewage and it is clear to the citysewage and drainage culvert in the sewage treatment system.comfort is very important topeoples lives.Mobile robots designed to clear the drainage culvert and the automaticcontrol system Free sewage culvert clear guarantee robot the robot is designed to clear theculvert sewage to the core.Control System is the core component of the development ofultrasonic range finder.Therefore it is very important to design a good ultrasonic rangefinder.2.A principle of ultrasonic distance measurement ‐7‐ 毕业设计（论文）英文翻译2.1 The principle of piezoelectric ultrasonic generator Piezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to work.Ultrasonic generator the internal structure as shown it has two piezoelectric chip and aresonance plate.When its two plus pulse signal the frequency equal to the intrinsicpiezoelectric oscillation frequency chip the chip will happen piezoelectric resonance andpromote the development of plate vibration resonance ultrasound is generated.Converselyif the two are not inter-electrode voltage when the board received ultrasonic resonance itwill be for vibration suppression of piezoelectric chip the mechanical energy is convertedto electrical signals then it becomes the ultrasonic receiver.The traditional way to determine the moment of the echos arrival is based onthresholding the received signal with a fixed reference.The threshold is chosen well abovethe noise level whereas the moment of arrival of an echo is defined as the first moment theecho signal surpasses that threshold.The intensity of an echo reflecting from an objectstrongly depends on the objects nature size and distance from the sensor.Further the timeinterval from the echos starting point to the moment when it surpasses the thresholdchanges with the intensity of the echo.As a consequence a considerable error may occurEven two echoes with different intensities arriving exactly at the same time will surpass thethreshold at different moments.The stronger one will surpass the threshold earlier than theweaker so it will be considered as belonging to a nearer object.2.2The principle of ultrasonic distance measurement Ultrasonic transmitter in a direction to launch ultrasound in the moment to launch thebeginning of time at the same time the spread of ultrasound in the air obstacles on his wayto return immediately the ultrasonic reflected wave received by the receiver immediatelystop the clock.Ultrasound in the air as the propagation velocity of 340m / s according tothe timer records the time t we can calculate the distance between the launch distancebarrier s that is: s 340t / 23.Ultrasonic Ranging System for the Second Circuit Design ‐8‐ 毕业设计（论文）英文翻译 System is characterized by single-chip microcomputer to control the use of ultrasonictransmitter and ultrasonic receiver since the launch from time to time single-chip selectionof 8751 economic-to-use and the chip has 4K of ROM to facilitate programming.Circuitschematic diagram shown in Figure 2.Figure 1 circuit principle diagram ‐9‐ 毕业设计（论文）英文翻译3.1 40 kHz ultrasonic pulse generated with the launch Ranging system using the ultrasonic sensor of piezoelectric ceramic sensors UCM40its operating voltage of the pulse signal is 40kHz which by the single-chip implementationof the following procedures to generate.puzel: mov 14h 12h ultrasonic firing continued 200mshere: cpl p1.0 output 40kHz square wave nop nop nop djnz 14h here ret Ranging in front of single-chip termination circuit P1.0 input port single chipimplementation of the above procedure the P1.0 port in a 40kHz pulse output signal afteramplification transistor T the drive to launch the first ultrasonic UCM40T issued 40kHzultrasonic pulse and the continued launch of 200ms.Ranging the right and the left side ofthe circuit respectively then input port P1.1 and P1.2 the working principle and circuit infront of the same location.3.2 Reception and processing of ultrasonic Used to receive the first launch of the first pair UCM40R the ultrasonic pulsemodulation signal into an alternating voltage the op-amp amplification IC1A and afterpolarization IC1B to IC2.IC2 is locked loop with audio decoder chip LM567 internalvoltage-controlled oscillator center frequency of f0 1/1.1R8C3 capacitor C4 determinetheir target bandwidth.R8-conditioning in the launch of the carrier frequency on theLM567 input signal is greater than 25mV the output from the high jump 8 feet into alow-level as interrupt request signals to the single-chip processing.Ranging in front of single-chip termination circuit output port INT0 interrupt thehighest priority right or left location of the output circuit with output gate IC3A accessINT1 port single-chip while single-chip P1.3 and P1.4 received input IC3A interrupted ‐10‐ 毕业设计（论文）英文翻译by the process to identify the source of inquiry to deal with interrupt priority level for thefirst left right after.Part of the source code is as follows:receive1: push psw push acc clr ex1 related external interrupt 1 jnb p1.1 right P1.1 pin to 0 ranging from right to interrupt serviceroutine circuit jnb p1.2 left P1.2 pin to 0 to the left ranging circuit interruptservice routinereturn: SETB EX1 open external interrupt 1 pop acc pop psw retiright:...right location entrance circuit interrupt service routine Ajmp Returnleft:...left Ranging entrance circuit interrupt service routine Ajmp Return3.3 The calculation of ultrasonic propagation time When you start firing at the same time start the single-chip circuitry within the timerT0 the use of timer counting function records the time and the launch of ultrasonicreflected wave received time.When you receive the ultrasonic reflected wave the receivercircuit outputs a negative jump in the end of INT0 or INT1 interrupt request generates asignal single-chip microcomputer in response to external interrupt request theimplementation of the external interrupt service subroutine read the time differencecalculating the distance.Some of its source code is as follows:RECEIVE0: PUSH PSW PUSH ACC CLR EX0 related external interrupt 0.

第三篇：中英文对照资料外文翻译文献

中英文对照资料外文翻译文献

平设计任何时期平面设计可以参照一些艺术和专业学科侧重于视觉传达和介绍。采用多种方式相结合，创造和符号，图像和语句创建一个代表性的想法和信息。平面设计师可以使用印刷，视觉艺术和排版技术产生的最终结果。平面设计常常提到的进程，其中沟通是创造和产品设计。共同使用的平面设计包括杂志，广告，产品包装和网页设计。例如，可能包括产品包装的标志或其他艺术作品，举办文字和纯粹的设计元素，如形状和颜色统一件。组成的一个最重要的特点，尤其是平面设计在使用前现有材料或不同的元素。平面设计涵盖了人类历史上诸多领域，在此漫长的历史和在相对最近爆炸视觉传达中的第20和21世纪，人们有时是模糊的区别和重叠的广告艺术，平面设计和美术。毕竟，他们有着许多相同的内容，理论，原则，做法和语言，有时同样的客人或客户。广告艺术的最终目标是出售的商品和服务。在平面设计，“其实质是使以信息，形成以思想，言论和感觉的经验”。在唐朝（618-906）之间的第4和第7世纪的木块被切断打印纺织品和后重现佛典。阿藏印在868是已知最早的印刷书籍。在19世纪后期欧洲，尤其是在英国，平面设计开始以独立的运动从美术中分离出来。蒙德里安称为父亲的图形设计。他是一个很好的艺术家，但是他在现代广告中利用现代电网系统在广告、印刷和网络布局网格。于1849年，在大不列颠亨利科尔成为的主要力量之一在设计教育界，该国政府通告设计在杂志设计和制造的重要性。他组织了大型的展览作为庆祝现代工业技术和维多利亚式的设计。从1892年至1896年威廉•莫里斯凯尔姆斯科特出版社出版的书籍的一些最重要的平面设计产品和工艺美术运动，并提出了一个非常赚钱的商机就是出版伟大文本论的图书并以高价出售给富人。莫里斯证明了市场的存在使平面设计在他们自己拥有的权利，并帮助开拓者从生产和美术分离设计。这历史相对论是，然而，重要的，因为它为第一次重大的反应对于十九世纪的陈旧的平面设计。莫里斯的工作，以及与其他私营新闻运动，直接影响新艺术风格和间接负责20世纪初非专业性平面设计的事态发展。谁创造了最初的“平面设计”似乎存在争议。这被归因于英国的设计师和大学教授Richard Guyatt，但另一消息来源于20世纪初美国图书设计师William Addison Dwiggins。伦敦地铁的标志设计是爱德华约翰斯顿于1916年设计的一个经典的现代而且使用了系统字体设计。在20世纪20年代，苏联的建构主义应用于“智能生产”在不同领域的生产。个性化的运动艺术在 2 俄罗斯大革命是没有价值的，从而走向以创造物体的功利为目的。他们设计的建筑、剧院集、海报、面料、服装、家具、徽标、菜单等。Jan Tschichold 在他的1928年书中编纂了新的现代印刷原则，他后来否认他在这本书的法西斯主义哲学主张，但它仍然是非常有影响力。Tschichold，包豪斯印刷专家如赫伯特拜耳和拉斯洛莫霍伊一纳吉，和El Lissitzky 是平面设计之父都被我们今天所知。他们首创的生产技术和文体设备，主要用于整个二十世纪。随后的几年看到平面设计在现代风格获得广泛的接受和应用。第二次世界大战结束后，美国经济的建立更需要平面设计，主要是广告和包装等。移居国外的德国包豪斯设计学院于1937年到芝加哥带来了“大规模生产”极简到美国;引发野火的“现代”建筑和设计。值得注意的名称世纪中叶现代设计包括阿德里安Frutiger，设计师和Frutiger字体大学;保兰德，从20世纪30年代后期，直到他去世于1996年，采取的原则和适用包豪斯他们受欢迎的广告和标志设计，帮助创造一个独特的办法，美国的欧洲简约而成为一个主要的先驱。平面设计称为企业形象;约瑟夫米勒，罗克曼，设计的海报严重尚未获取1950年代和1960年代时代典型。从道路标志到技术图表，从备忘录到参考手册，增强了平面设计的知识转让。可读性增强了文字的视觉效果。设计还可以通过理念或有效的视觉传播帮助销售产品。将它应用到产品和公司识别系统的要素像标志、颜色和文字。连同这些被定义为品牌。品牌已日益成为重要的提供的服务范围，许多平面设计师，企业形象和条件往往是同时交替使用。教科书的目的是本科目，如地理、科学和数学。这些出版物已布局理论设计说明和图表。一个常见的例子，在使用图形，教育是图表人体解剖学。平面设计也适用于布局和格式的教育材料，使信息更容易和更容易理解的。平面设计是应用在娱乐行业的装饰，景观和视觉故事。其他的例子娱乐设计用途包括小说，漫画，电影中的开幕和闭幕，在舞台上节目的和道具的安排。这也包括艺术品在T恤衫的应用和其他物品的出售。从科学杂志报道，提出意见和事实往往是提高图形和深思熟虑的组成视觉信息-被称为信息的设计。报纸，杂志，博客，电视和电影纪录片，可以使用平面设计通知及娱乐。随着网络，信息与经验的交互设计的工具，Adobe和Flash正越来越多地被用来说明的背景新闻。一个平面设计项目可能涉及程式化和介绍现有的文字，或者事先存在的意向或图像开发的平面设计师。例如，一家报纸的故事始于记者和摄影记者，然后成为平面设计师的工作安排到一个合理的页面布局，并确定是否有任何其他图形元素应当要求。在一本杂志的文章或广告，往往是平面设计师或艺术总监将委员会摄影师或插图创建原始文件只是被纳入设计规划。现代设计的做法已经扩展到了现代的计算机，例如在使用所见的用户界面，通常被称为交互式设计，或多媒体设计。任何图形元素用于设计之前，图形元素必须是源于通过视觉艺术技能。这些图形通常（但并不总是）被设计师开发。视觉艺术的作品主要是视觉性的东西从使用传统的传播媒介、摄影或电脑产生的艺术。平面设计原则可以适用于每一个人的版画艺术元素，并最终组成。3 印刷术是艺术，工艺和技术型，修改类型字形，并安排类型的设计。类型字形（字符）的创建和修改使用各种说明方法。这项安排的类型是选择字体、大小、线长、主要的（行距）和文字的间距。刷术是由排字工机，排字，印刷工人，图形艺术家，艺术总监，工作者和办事员。直到数字时代，印刷成为一个专业的领域。数字化开辟了新的视觉设计师和用户。排版设计师平面设计的一部分，是在网页设计中是图形设计，处理安排风格（内容）的要素。从早期的照明网页手工复制书籍的中世纪和程序，以错综复杂的现代杂志和目录布局，适当的网页设计公司长期以来一直是考虑的印刷材料，与印刷媒体，内容通常包括类型（文字，图片（照片）偶尔发生持有者图形的内容，没有印刷油墨，如模具/激光切割，烫金压印或盲目压花。平面设计师常常专心研究于界面设计，如网页设计和软件设计，最终用户的交互性是一个设计考虑的布局或接口。视觉沟通技巧、互动沟通技巧与用户互动得相结合和在线品牌推广，平面设计师往往与软件开发和网络开发人员创建的外观和风格的网站或软件应用程序，来加强用户或网络网站的访问者互动体验。版画是在纸上，其他有机材料或者表面上印刷艺术品的过程。每一张不会被复制，但时最初的因为它不是一个复制的另一艺术作品，并在技术上称为留下深刻的印象。绘画或素描，另一方面，创造了独特的原始艺术品。版画是由一个单一的原始表面创造的，在技术上已经作为基质而被已知。常见的矩阵包括：金属板，通常是铜或锌的雕刻或蚀刻石料，用于光刻;块木刻的木材，油毡和织物板的丝网印刷。但也有许多其他种类，讨论如下：作品从一个单一的印刷板创造一个版本，在现代通常每个签署和编号，形成限量。打印也可编制成册，作为艺术家的书籍。一个单一的打印可能是产品的一种或多种技术。色彩学领域是如何在打印机上和显示器上用眼睛识别颜色和如何解释和组织这些色彩。眼睛的视网膜被两个被命名为视杆和视锥的感光体涵盖。视杆对光很敏感但是对颜色不是很敏感。视锥却与视杆恰恰相反。他们对光不太敏感，但是颜色可以被感知。随着科技的发展，人们越来越认识到环境问题日益严重，大气污染、森林破坏、水土流失、土地沙漠

化、水资源污染、大量物种灭绝、石油、天然气、煤等资源枯竭。作为工业设计师，应该有强烈的环境 保护意识，使得自己的设计建立在不破坏环境及节约自然资源的基础上。

其中，温室效应、臭氧层破坏和酸雨是当今全球性的三大环境问题。

温室效应就是大气变暖的效应其形成原因是太阳短波辐射可以透过大气射入地面，而地面增暖后放

出的长波辐射却被大气中的二氧化碳就像一层厚厚的玻璃，把地球变成了一个大暖房。甲烷、臭氧、氯、氟烃以及水汽等也对温室效应有所贡献。随着人口的急剧增加和工业的迅速发展，越来越多的二氧化碳 排入大气中；

又由于森林被大量砍伐，大气中原本应被森林吸收的二氧化碳没有被吸收，致使二氧化碳 逐渐增加，温室效应也不断增强。温室效应的后果十分严重，自然生态将随之发生重大变化，荒漠将扩

大，土地侵蚀加重，森林退向极地，旱涝灾害严重，雨量增加；温带冬天更湿、夏天更旱；热带也将变 得更湿，干热的亚热带变得更干旱，迫使原有水利工程重新调整。沿海将受到严重威胁。由于气温升高，两极冰块将融化，使海平面上升，将会淹没许多城市和港口。

臭氧层破坏现象引起科学界及整个国际社会的震动。美国的两位科学家 Monila 和 Rowland 指出，正是人为的活动造成了今天的臭氧洞。元凶就是现在所熟知的氟利昂和哈龙。

酸雨目前已成为一种范围广泛、跨越国界的大气污染现象。酸雨破坏土壤，使湖泊酸化，危害动植

物生长；刺激人的皮肤，诱发皮肤病，引起肺水肿、肺硬化；会腐蚀金属制品、油漆、皮革、纺织品和 含碳酸盐的建筑。

总而言之，人类生活的环境已经日益恶化。

而恶化的原因大部分属于人类本身的不良生活方式和不 尊重客观规律，急功近利，对于地球资源的使用没有科学的计划性，而且在设计、制造产品以及日常生

活中缺乏保护环境的意识，以至于自毁家园，其危害不仅于当代，而且严重影响了子孙后代的生存。

环境问题在很大程度上是由于人们的不良设计、生活方式造成的后果。于是给设计师们提出了一个

严肃的问题：作为设计师，应肩负起保护环境的历史重任！

工业在为人类创造大量物质财富的同时，也给世界带来了灾难。工业设计在为人类创造了现代生活

方式的同时，也加速了资源、能源的消耗，并对地球的生态平衡造成了巨大的破坏。

所以，作为工业设计师，建立环境意识体现了其道德和社会责任心。设计师必须对自己的设计负责，必须把人类的健康幸福，自然与人类的和谐共存作为设计中心遵循的原则。

设计师还必须掌握必要的材料、工艺、化工、制造等方面的知识，使得其设计不对环境造成危害而 成为可能。

“可持续发展设计” 这一概念的提出，对于人性的回归及世界真正意义上的发展具有划时代的意义。他体现了设计师的道德与责任，已成为 21 世纪设计发展的总趋势。从此，人类传统工业文明发展模式

转向现代生态文明发展模式。它是社会进步，经济增长，环境保护三者之间的协同。

可持续发展是人们应遵循的一种全新的伦理、道德和价值观念。其本质在于：充分利用现代科技，大力开发绿色资源，发展清洁生产，不断改善和优化生态环境，促使人与自然的和谐发展，人口、资源 和环境相互协调。

解决可持续反展问题是一个技术创新和行为模式转变的问题。

可持续发展战略是解决在不危害未来几代人的需求前提下，尽量满足当代人的需求的问题。实现目

前利益与长远利益的统一，为子孙后代留下发展空间。

目前可持续发展战略考虑的问题有：循环性、绿色能源、生态效率。

绿色设计源于人们对于现代技术文化所引起的环境及生态破坏的反思。绿色设计着眼于人与自然的

生态平衡关系，在设计过程的每一个决策中都充分考虑到环境效益，尽量减少对环境的破坏。

对工业设计师而言，绿色设计的核心是“ 3R ”，即“减少”（Reduce）、“再循环”(Recycle)和“再 利用”（Reuse)。不仅要尽量减少物质和能源的消耗、减少有害物质的排放，而且要使产品及零件能够 5 方便的分类回收，并再生循环或重新利用。

绿色设计不仅是一种技术层面的考虑，更重要的是一种观念 上的变革。

要求设计师放弃那种过分强调产品在外观上标新立异的做法，而将重点放在真正意义上的创 新上面，已一种更为负责的方法去创造产品的形态，用更简洁、长久的造型使产品尽可能地延长其使用 寿命。

从材料方面要考虑： 原材料的存量和可再生性，获取材料时的环境能源的消耗与污染，后续加工时

环境材料的易加工性，低能耗性、低污染性，报废时的可回收性。

从加工制造方面要考虑：加工制造阶段需要将污染减至最少，或将污染消灭在生产过程初始阶段。

从包装、运输、销售等方面要考虑：包装的环境性能、绿色包装，良好的可运输性、降低自重、减 少能耗，当地化生产及减少物流过程消耗。

从产品的使用阶段考虑： 使用中的能耗、资源消耗。

产品更新换代时环境性能的模块化、可重组性、产品的使用模式等因素。

从产品的报废阶段考虑：易拆卸性，便于分解和分类，材料可回收性和可再利用性，零部件可重组 性或移作它用等因素。

清洁的能源：如考虑太阳能、水电、风力的清洁燃料；清洁的材料，涉及低污染、无毒、易降解和 可回收性；清洁的制造过程，考虑低能耗、少排放的制造；清洁的产品，涉及使用中节能、环保、报废 后的回收。

零部件的再生利用湿可持续战略的有力措施。事实证明： 报废的产品拆卸后，经分析，其中材料在

改进设计后可重用和经翻新后可重用的比例可以提高。

比如：一辆报废车中，金属材料占 80 ％，其中，有色金属占 3 ％～ 4.7 ％。世界钢产量中的 45 ％是 由废钢铁生产出的。中国钢产量的 25 ％是由废钢铁生产的。

产品全生命周期管理是指从人对产品的需求开始，到产品淘汰报废的全部生命历程。其中包括产

品需求分析产品计划、概念设计、产品设计、数字化仿真、工艺准备、工艺规划、生产测试和质量监控、销售与分销、使用、维护与维修，以及报废与回收等主要阶段。将先进的管理理念和一流的信息技术有

机融入到现代企业的工业和商业运作中，从而使企业在数字经济时代能够有效地调整经营手段和管理方式，以发挥企业前所未有的竞争优势。帮助企业进行产品创新，赢得市场，并获得额外利润，以提高企业产品的价值。

GRAPHIC DESIGN The term graphic design can refer to a number of artistic and professional disciplines which focus on visual communication and presentation.Various methods are used to create and combine symbols, images and/or words to create a visual representation of ideas and messages.A graphic designer may use typography, visual arts and page layout techniques to produce the final result.Graphic design often refers to both the process by which the communication is created and the products which are generated.Common uses of graphic design include magazines, advertisements, product packaging and web design.For example, a product package might include a logo or other artwork, organized text and pure design elements such as shapes and color which unify the piece.Composition is one of the most important features of graphic design especially when using pre-existing materials or diverse elements.Graphic Design spans the history of humankind from the caves of Lascaux to the dazzling neons of Ginza.In both this lengthy history and in the relatively recent explosion of visual communication in the 20th and 21st centuries, there is sometimes a blurring distinction and over-lapping of advertising art, graphic design and fine art.After all, they share many of the same elements, theories, principles, practices and languages, and sometimes the same benefactor or client.In advertising art the ultimate objective is the sale of goods and services.In graphic design, “the essence is to give order to information, form to ideas, expression and feeling to artifacts that document human experience.” During the Tang dynasty(618–906)between the 4th and 7th century A.D.wood blocks were cut to print on textiles and later to reproduce Buddhist texts.A Buddhist scripture printed in 868 is the earliest known printed book.In late 19th century Europe, especially in the United Kingdom, the movement began to separate graphic design from fine art.Piet Mondrian is known as the father of graphic design.He was a fine artist, but his use of grids inspired the modern grid system used today in advertising, print and web layout.In 1849, Henry Cole became one of the major forces in design education in Great Britain, informing the government of the importance of design in his Journal of Design and Manufactures.He organized the Great Exhibition as a celebration of modern industrial technology and Victorian design.From 1892 to 1896 William Morris' Kelmscott Press published books that are some of the most significant of the graphic design products of the Arts and Crafts movement, and 2 made a very lucrative business of creating books of great stylistic refinement and selling them to the wealthy for a premium.Morris proved that a market existed for works of graphic design in their own right and helped pioneer the separation of design from production and from fine art.The work of the Kelmscott Press is characterized by its obsession with historical styles.This historicism was, however, important as it amounted to the first significant reaction to the stale state of nineteenth-century graphic design.Morris' work, along with the rest of the Private Press movement, directly influenced Art Nouveau and is indirectly responsible for developments in early twentieth century graphic design in general.Who originally coined the term “graphic design” appears to be in dispute.It has been attributed to Richard Guyatt, the British designer and academic, but another source suggests William Addison Dwiggins, an American book designer in the early 20th century The signage in the London Underground is a classic of the modern era and used a font designed by Edward Johnston in 1916.In the 1920s, Soviet constructivism applied 'intellectual production' in different spheres of production.The movement saw individualistic art as useless in revolutionary Russia and thus moved towards creating objects for utilitarian purposes.They designed buildings, theater sets, posters, fabrics, clothing, furniture, logos, menus, etc.Jan Tschichold codified the principles of modern typography in his 1928 book, New Typography.He later repudiated the philosophy he espoused in this book as being fascistic, but it remained very influential.Tschichold, Bauhaus typographers such as Herbert Bayer and Laszlo Moholy-Nagy, and El Lissitzky are the fathers of graphic design as we know it today.They pioneered production techniques and stylistic devices used throughout the twentieth century.The following years saw graphic design in the modern style gain widespread acceptance and application.A booming post-World War II American economy established a greater need for graphic design, mainly advertising and packaging.The emigration of the German Bauhaus school of design to Chicago in 1937 brought a “mass-produced”minimalism to America;sparking a wild fire of “modern”architecture and design.Notable names in mid-century modern design include Adrian Frutiger, designer of the typefaces Univers and Frutiger;Paul Rand, who, from the late 1930s until his death in 1996, took the principles of the Bauhaus and applied them to popular advertising and logo design, helping to create a uniquely American approach to European minimalism while becoming one of the principal pioneers of the subset of graphic design known as corporate identity；and Josef Müller-Brockmann, who designed posters in a severe yet accessible manner typical of the 1950s and 1960s era.3 From road signs to technical schematics, from interoffice memorandums to reference manuals, graphic design enhances transfer of knowledge.Readability is enhanced by improving the visual presentation of text.Design can also aid in selling a product or idea through effective visual communication.It is applied to products and elements of company identity like logos, colors, and text.Together these are defined as branding(see also advertising).Branding has increasingly become important in the range of services offered by many graphic designers, alongside corporate identity, and the terms are often used interchangeably.Textbooks are designed to present subjects such as geography, science, and math.These publications have layouts which illustrate theories and diagrams.A common example of graphics in use to educate is diagrams of human anatomy.Graphic design is also applied to layout and formatting of educational material to make the information more accessible and more readily understandable.Graphic design is applied in the entertainment industry in decoration, scenery, and visual story telling.Other examples of design for entertainment purposes include novels, comic books, opening credits and closing credits in film, and programs and props on stage.This could also include artwork used for t-shirts and other items screenprinted for sale.From scientific journals to news reporting, the presentation of opinion and facts is often improved with graphics and thoughtful compositions of visual information-known as information design.Newspapers, magazines, blogs, television and film documentaries may use graphic design to inform and entertain.With the advent of the web, information designers with experience in interactive tools such as Adobe Flash are increasingly being used to illustrate the background to news stories.A graphic design project may involve the stylization and presentation of existing text and either preexisting imagery or images developed by the graphic designer.For example, a newspaper story begins with the journalists and photojournalists and then becomes the graphic designer's job to organize the page into a reasonable layout and determine if any other graphic elements should be required.In a magazine article or advertisement, often the graphic designer or art director will commission photographers or illustrators to create original pieces just to be incorporated into the design layout.Contemporary design practice has been extended to the modern computer, for example in the use of WYSIWYG user interfaces, often referred to as interactive design, or multimedia design.Before any graphic elements may be applied to a design, the graphic elements must be originated by means of visual art skills.These graphics are often(but not always)developed 4 by a graphic designer.Visual arts include works which are primarily visual in nature using anything from traditional media, to photography or computer generated art.Graphic design principles may be applied to each graphic art element individually as well as to the final composition.Typography is the art, craft and techniques of type design, modifying type glyphs, and arranging type.Type glyphs(characters)are created and modified using a variety of illustration techniques.The arrangement of type is the selection of typefaces, point size, line length, leading(line spacing)and letter spacing.Typography is performed by typesetters, compositors, typographers, graphic artists, art directors, and clerical workers.Until the Digital Age, typography was a specialized occupation.Digitization opened up typography to new generations of visual designers and lay users.Page layout is the part of graphic design that deals in the arrangement and style treatment of elements(content)on a page.Beginning from early illuminated pages in hand-copied books of the Middle Ages and proceeding down to intricate modern magazine and catalog layouts, proper page design has long been a consideration in printed material.With print media, elements usually consist of type(text), images(pictures), and occasionally place-holder graphics for elements that are not printed with ink such as die/laser cutting, foil stamping or blind embossing.Graphic designers are often involved in interface design, such as web design and software design when end user interactivity is a design consideration of the layout or interface.Combining visual communication skills with the interactive communication skills of user interaction and online branding, graphic designers often work with software developers and web developers to create both the look and feel of a web site or software application and enhance the interactive experience of the user or web site visitor.Printmaking is the process of making artworks by printing on paper and other materials or surfaces.Except in the case of monotyping, the process is capable of producing multiples of the same piece, which is called a print.Each piece is not a copy but an original since it is not a reproduction of another work of art and is technically known as an impression.Painting or drawing, on the other hand, create a unique original piece of artwork.Prints are created from a single original surface, known technically as a matrix.Common types of matrices include: plates of metal, usually copper or zinc for engraving or etching;stone, used for lithography;blocks of wood for woodcuts, linoleum for linocuts and fabric plates for screen-printing.But there are many other kinds, discussed below.Works printed from a single

第四篇：毕业论文外文翻译

齿轮和轴的介绍

摘 要:在传统机械和现代机械中齿轮和轴的重要地位是不可动摇的。齿轮和轴主要 安装在主轴箱来传递力的方向。通过加工制造它们可以分为许多的型号，分别用于许 多的场合。所以我们对齿轮和轴的了解和认识必须是多层次多方位的。关键词:齿轮；轴 关键词 在直齿圆柱齿轮的受力分析中，是假定各力作用在单一平面的。我们将研究作用 力具有三维坐标的齿轮。因此，在斜齿轮的情况下，其齿向是不平行于回转轴线的。而在锥齿轮的情况中各回转轴线互相不平行。像我们要讨论的那样，尚有其他道理需 要学习，掌握。斜齿轮用于传递平行轴之间的运动。倾斜角度每个齿轮都一样，但一个必须右旋 斜齿，而另一个必须是左旋斜齿。齿的形状是一溅开线螺旋面。如果一张被剪成平行 四边形（矩形）的纸张包围在齿轮圆柱体上，纸上印出齿的角刃边就变成斜线。如果 我展开这张纸，在血角刃边上的每一个点就发生一渐开线曲线。直齿圆柱齿轮轮齿的初始接触处是跨过整个齿面而伸展开来的线。斜齿轮轮齿的 初始接触是一点，当齿进入更多的啮合时，它就变成线。在直齿圆柱齿轮中，接触是平行于回转轴线的。在斜齿轮中，该先是跨过齿面的对角线。它是齿轮逐渐进行啮合 并平稳的从一个齿到另一个齿传递运动，那样就使斜齿轮具有高速重载下平稳传递运 动的能力。斜齿轮使轴的轴承承受径向和轴向力。当轴向推力变的大了或由于别的原 因而产生某些影响时，那就可以使用人字齿轮。双斜齿轮（人字齿轮）是与反向的并 排地装在同一轴上的两个斜齿轮等效。他们产生相反的轴向推力作用，这样就消除了 轴向推力。当两个或更多个单向齿斜齿轮被在同一轴上时，齿轮的齿向应作选择，以 便产生最小的轴向推力。交错轴斜齿轮或螺旋齿轮，他们是轴中心线既不相交也不平行。交错轴斜齿轮的 齿彼此之间发生点接触，它随着齿轮的磨合而变成线接触。因此他们只能传递小的载 荷和主要用于仪器设备中，而且肯定不能推荐在动力传动中使用。交错轴斜齿轮与斜 齿轮之间在被安装后互相捏合之前是没有任何区别的。它们是以同样的方法进行制 造。一对相啮合的交错轴斜齿轮通常具有同样的齿向，即左旋主动齿轮跟右旋从动齿 轮相啮合。在交错轴斜齿设计中，当该齿的斜角相等时所产生滑移速度最小。然而当

该齿的斜角不相等时，如果两个齿轮具有相同齿向的话，大斜角齿轮应用作主动齿轮。蜗轮与交错轴斜齿轮相似。小齿轮即蜗杆具有较小的齿数，通常是一到四齿，由 于它们完全缠绕在节圆柱上，因此它们被称为螺纹齿。与其相配的齿轮叫做蜗轮，蜗 轮不是真正的斜齿轮。蜗杆和蜗轮通常是用于向垂直相交轴之间的传动提供大的角速 度减速比。蜗轮不是斜齿轮，因为其齿顶面做成中凹形状以适配蜗杆曲率，目的是要 形成线接触而不是点接触。然而蜗杆蜗轮传动机构中存在齿间有较大滑移速度的缺 点，正像交错轴斜齿轮那样。蜗杆蜗轮机构有单包围和双包围机构。单包围机构就是蜗轮包裹着蜗杆的一种机 构。当然，如果每个构件各自局部地包围着对方的蜗轮机构就是双包围蜗轮蜗杆机构。着两者之间的重要区别是，在双包围蜗轮组的轮齿间有面接触，而在单包围的蜗轮组 的轮齿间有线接触。一个装置中的蜗杆和蜗轮正像交错轴斜齿轮那样具有相同的齿 向，但是其斜齿齿角的角度是极不相同的。蜗杆上的齿斜角度通常很大，而蜗轮上的 则极小，因此习惯常规定蜗杆的导角，那就是蜗杆齿斜角的余角；也规定了蜗轮上的 齿斜角，该两角之和就等于 90 度的轴线交角。当齿轮要用来传递相交轴之间的运动时，就需要某种形式的锥齿轮。虽然锥齿轮 通常制造成能构成 90 度轴交角，但它们也可产生任何角度的轴交角。轮齿可以铸出，铣制或滚切加工。仅就滚齿而言就可达一级精度。在典型的锥齿轮安装中，其中一个 锥齿轮常常装于支承的外侧。这意味着轴的挠曲情况更加明显而使在轮齿接触上具有 更大的影响。另外一个难题，发生在难于预示锥齿轮轮齿上的应力，实际上是由于齿轮被加工 成锥状造成的。直齿锥齿轮易于设计且制造简单，如果他们安装的精密而确定，在运转中会产生 良好效果。然而在直齿圆柱齿轮情况下，在节线速度较高时，他们将发出噪音。在这 些

情况下，螺旋锥齿轮比直齿轮能产生平稳的多的啮合作用，因此碰到高速运转的场 合那是很有用的。当在汽车的各种不同用途中，有一个带偏心轴的类似锥齿轮的机构，那是常常所希望的。这样的齿轮机构叫做准双曲面齿轮机构，因为它们的节面是双曲 回转面。这种齿轮之间的轮齿作用是沿着一根直线上产生滚动与滑动相结合的运动并 和蜗轮蜗杆的轮齿作用有着更多的共同之处。轴是一种转动或静止的杆件。通常有圆形横截面。在轴上安装像齿轮，皮带轮，飞轮，曲柄，链轮和其他动力传递零件。轴能够承受弯曲，拉伸，压缩或扭转载荷，这些力相结合时，人们期望找到静强度和疲劳强度作为设计的重要依据。因为单根轴 可以承受静压力，变应力和交变应力，所有的应力作用都是同时发生的。“轴”这个词包含着多种含义，例如心轴和主轴。心轴也是轴，既可以旋转也可 以静止的轴，但不承受扭转载荷。短的转动轴常常被称为主轴。当轴的弯曲或扭转变形必需被限制于很小的范围内时，其尺寸应根据变形来确 定，然后进行应力分析。因此，如若轴要做得有足够的刚度以致挠曲不太大，那么合 应力符合安全要求那是完全可能的。但决不意味着设计者要保证；它们是安全的，轴 几乎总是要进行计算的，知道它们是处在可以接受的允许的极限以内。因之，设计者 无论何时，动力传递零件，如齿轮或皮带轮都应该设置在靠近支持轴承附近。这就减 低了弯矩，因而减小变形和弯曲应力。虽然来自 M.H.G 方法在设计轴中难于应用，但它可能用来准确预示实际失效。这 样，它是一个检验已经设计好了的轴的或者发现具体轴在运转中发生损坏原因的好方 法。进而有着大量的关于设计的问题，其中由于别的考虑例如刚度考虑，尺寸已得到 较好的限制。设计者去查找关于圆角尺寸、热处理、表面光洁度和是否要进行喷丸处理等资料，那真正的唯一的需要是实现所要求的寿命和可靠性。由于他们的功能相似，将离合器和制动器一起处理。简化摩擦离合器或制动器的 动力学表达式中，各自以角速度 w1 和 w2 运动的两个转动惯量 I1 和 I2，在制动器情 况下其中之一可能是零，由于接上离合器或制动器而最终要导致同样的速度。因为两 个构件开始以不同速度运转而使打滑发生了，并且在作用过程中能量散失，结果导致 温升。在分析这些装置的性能时，我们应注意到作用力，传递的扭矩，散失的能量和 温升。所传递的扭矩关系到作用力，摩擦系数和离合器或制动器的几何状况。这是一 个静力学问题。这个问题将必须对每个几何机构形状分别进行研究。然而温升与能量 损失有关，研究温升可能与制动器或离合器的类型无关。因为几何形状的重要性是散 热表面。各种各样的离合器和制动器可作如下分类： 1．轮缘式内膨胀制冻块； 2．轮缘式外接触制动块； 3．条带式； 4．盘型或轴向式； 5．圆锥型；

6．混合式。分析摩擦离合器和制动器的各种形式都应用一般的同样的程序，下面的步骤是必 需的： 1．假定或确定摩擦表面上压力分布； 2．找出最大压力和任一点处压力之间的关系； 3．应用静平衡条件去找寻（a）作用力；（b）扭矩；(c)支反力。混合式离合器包括几个类型，例如强制接触离合器、超载释放保护离合器、超越 离合器、磁液离合器等等。强制接触离合器由一个变位杆和两个夹爪组成。各种强制接触离合器之间最大的 区别与夹爪的设计有关。为了在结合过程中给变换作用予较长时间周期，夹爪可以是 棘轮式的，螺旋型或齿型的。有时使用许多齿或夹爪。他们可能在圆周面上加工齿，以便他们以圆柱周向配合来结合或者在配合元件的端面上加工齿来结合。虽然强制离合器不像摩擦接触离合器用的那么广泛，但它们确实有很重要的运 用。离合器需要同步操作。有些装置例如线性驱动装置或电机操作螺杆驱动器必须运行到一定的限度然后 停顿下来。为着这些用途就需要超载释放保护离合器。这些离合器通常用弹簧加载，以使得在达到预定的力矩时释放。当到达超载点时听到的“喀嚓”声就被认定为是所 希望的信号声。超越离合器

或连轴器允许机器的被动构件“空转”或“超越”，因为主动驱动件 停顿了或者因为另一个动力源使被动构件增加了速度。这种离合器通常使用装在外套 筒和内轴件之间的滚子或滚珠。该内轴件，在它的周边加工了数个平面。驱动作用是 靠在套筒和平面之间契入的滚子来获得。因此该离合器与具有一定数量齿的棘轮棘爪 机构等效。磁液离合器或制动器相对来说是一个新的发展，它们具有两平行的磁极板。这些 磁极板之间有磁粉混合物润滑。电磁线圈被装入磁路中的某处。借助激励该线圈，磁 液混合物的剪切强度可被精确的控制。这样从充分滑移到完全锁住的任何状态都可以 获得。

GEAR AND SHAFT INTRODUCTION

Abstract: The important position of the wheel gear and shaft can't falter in

traditional machine and modern machines.The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box.The passing to process to make them can is divided into many model numbers, useding for many situations respectively.So we must be the multilayers to the understanding of the wheel gear and shaft in many ways.Key words: Wheel gear;Shaft

In the force analysis of spur gears, the forces are assumed to act in a single plane.We shall study gears in which the forces have three dimensions.The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation.And in the case of bevel gears, the rotational axes are not parallel to each other.There are also other reasons, as we shall learn.Helical gears are used to transmit motion between parallel shafts.The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix.The shape of the tooth is an involute helicoid.If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix.If we unwind this paper, each point on the angular edge generates an involute curve.The surface obtained when every point on the edge generates an involute is called an involute helicoid.The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth.The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement.In spur gears the line of contact is parallel to the axis of the rotation;in helical gears, the line is diagonal across the face of the tooth.It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high

speeds.Helical gears subject the shaft bearings to both radial and thrust loads.When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears.A double helical gear(herringbone)is equivalent to two helical gears of opposite hand, mounted side by side on the same shaft.They develop opposite thrust reactions and thus cancel out the thrust load.When two or more single helical gears are mounted on the same shaft, the hand of the gears should be selected so as to produce the minimum thrust load.Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting.The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in.For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power.There is on difference between a crossed helical gear and a helical gear until they are mounted in mesh with each other.They are manufactured in the same way.A pair of meshed crossed helical gears usually have the same hand;that is ,a right-hand driver goes with a

right-hand driven.In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle are equal.However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand.Worm gears are similar to crossed helical gears.The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads.Its mating gear is called a worm gear, which is not a true helical gear.A worm and worm gear are used to provide a high angular-velocity reduction between nonintersecting shafts which are usually at right angle.The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact.However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed

helical gears.Worm gearing are either single or double enveloping.A single-enveloping gearing is one in which the gear wraps around or partially encloses the worm..A gearing in which each element partially encloses the other is, of course, a double-enveloping worm gearing.The important difference between the two is that area contact exists between the teeth of double-enveloping gears while only line contact between those of single-enveloping gears.The worm and worm gear of a set have the same hand of helix as for crossed helical gears, but the helix angles are usually quite different.The helix angle on the worm is generally quite large, and that on the gear very small.Because of this, it is usual to specify the lead angle on the worm, which is the complement of the worm helix angle, and the helix angle on the gear;the two angles are equal for a 90-deg.Shaft angle.When gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required.Although bevel gear are usually made for a shaft angle of 90 deg.They may be produced for almost any shaft angle.The teeth may be cast, milled, or generated.Only the generated teeth may be classed as accurate.In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing.This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth.Another difficulty, which occurs in predicting the stress in bevel-gear teeth, is the fact the teeth are tapered.Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively.As in the case of squr gears, however, they become noisy at higher values of the pitch-line velocity.In these cases it is often good design practice to go to the spiral bevel gear, which is the bevel counterpart of the helical gear.As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered.7

It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset.Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution.The tooth action between such gears is a combination of rolling and sliding along a straight line and has much in common with that of worm gears.A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other power-transmission elements.Shaft may be subjected to bending, tension, compression, or torsional loads, acting singly or in combination with one another.When they are combined, one may expect to find both static and fatigue strength to be important design considerations, since a

single shaft may be subjected to static stresses, completely reversed, and repeated stresses, all acting at the same time.The word “shaft” covers numerous variations, such as axles and spindles.Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load.A shirt rotating shaft is often called a spindle.When either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of deflection before analyzing the stresses.The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe.But by no means should the designer assume that they are safe;it is almost always necessary to calculate them so that he knows they are within acceptable limits.Whenever possible, the power-transmission elements, such as gears or pullets, should be located close to the supporting bearings, This reduces the bending moment, and hence the deflection and bending stress.Although the von Mises-Hencky-Goodman method is difficult to use in design of shaft, it probably comes closest to predicting actual failure.Thus it is a good way of checking a shaft that has already been designed or of discovering

why a particular shaft has failed in service.Furthermore, there are a considerable number of shaft-design problems in which the dimension are pretty well limited by other considerations, such as rigidity, and it is only necessary for the designer to discover something about the fillet sizes, heat-treatment, and surface finish and whether or not shot peening is necessary in order to achieve the required life and reliability.Because of the similarity of their functions, clutches and brakes are treated together.In a simplified dynamic representation of a friction clutch, or brake, two inertias I1 and I2 traveling at the respective angular velocities W1 and W2, one of which may be zero in the case of brake, are to be brought to the same speed by engaging the clutch or brake.Slippage occurs because the two elements are running at different speeds and energy is dissipated during actuation, resulting in a temperature rise.In analyzing the performance of these devices we shall be interested in the actuating force, the torque transmitted, the energy loss and the temperature rise.The torque transmitted is related to the actuating force, the coefficient of friction, and the geometry of the clutch or brake.This is problem in static, which will have to be studied separately for eath geometric configuration.However, temperature rise is related to energy loss and can be studied without regard to the type of brake or clutch because the geometry of interest is the heat-dissipating surfaces.The various types of clutches and brakes may be classified as fllows:

1.Rim type with internally expanding shoes 2.Rim type with externally contracting shoes 3.Band type 4.Disk or axial type 5.Cone type 6.Miscellaneous type The analysis of all type of friction clutches and brakes use the same general procedure.The following step are necessary:

1.Assume or determine the distribution of pressure on the frictional surfaces.2.Find a relation between the maximum pressure and the pressure at any point 3.Apply the condition of statical equilibrium to find(a)the actuating force,(b)the torque, and(c)the support reactions.Miscellaneous clutches include several types, such as the

positive-contact clutches, overload-release clutches, overrunning clutches, magnetic fluid clutches, and others.A positive-contact clutch consists of a shift lever and two jaws.The greatest differences between the various types of positive clutches are concerned with the design of the jaws.To provide a longer period of time for shift action during engagement, the jaws may be ratchet-shaped, or gear-tooth-shaped.Sometimes a great many teeth or jaws are used, and they may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of

the mating elements.Although positive clutches are not used to the extent of the frictional-contact type, they do have important applications where

synchronous operation is required.Devices such as linear drives or motor-operated screw drivers must run to definite limit and then come to a stop.An overload-release type of clutch is required for these applications.These clutches are usually spring-loaded so as to release at a predetermined toque.The clicking sound which is heard when the overload point is reached is considered to be a desirable signal.An overrunning clutch or coupling permits the driven member of a machine to “freewheel” or “overrun” because the driver is stopped or because another source of power increase the speed of the driven.This type of clutch usually uses rollers or balls mounted between an outer sleeve and an inner member having flats machined around the periphery.Driving action is obtained by wedging the rollers between the sleeve and the flats.The clutch is

therefore equivalent to a pawl and ratchet with an infinite number of teeth.Magnetic fluid clutch or brake is a relatively new development which has two parallel magnetic plates.Between these plates is a lubricated magnetic powder mixture.An electromagnetic coil is inserted somewhere in the magnetic circuit.By varying the excitation to this coil, the shearing strength of the magnetic fluid mixture may be accurately controlled.Thus any condition from a full slip to a frozen lockup may be obtained.11

第五篇：毕业论文外文翻译

经济增速放缓对中国银行业的影响显现 Lagging Indicators: China's Banks and the Slowdown

摘要: Chinese banks' net income surged to record highs last year, defying the slowing growth on the world's second-largest economy.Is it indicating that banks are resilient to the economic downturn?Not nec...Chinese banks' net income surged to record highs last year, defying the slowing growth on the world's second-largest economy.Is it indicating that banks are resilient to the economic downturn?

Not necessarily.The banks have a tendency to be lagging indicators.Only after a certain amount of time has passed will China's macro situation show up on the bottom line.Take, for example, bad loans.They're finally growing, incrementally, after years of declining.Industrial & Commercial Bank of China Ltd., the nation's largest bank by assets, saw its

nonperforming loans rise by 3.82 billion yuan(about $606 million)in the fourth quarter;China Construction Bank Corp., the No.2 bank on the mainland, reported a 6.27 billion yuan rise in such loans.Bank of China Ltd.'s bad loans in the fourth quarter rose 1.39 billion yuan.(In China, nonperforming loans are those that have at least a 30% chance of turning sour.)

Smaller banks also saw some increases in bad loans.China Minsheng Banking Corp., the

country's largest non-state-owned bank, posted a rise of 200 million yuan in nonperforming loans in 2011.Such loans at Industrial Bank Co.grew by 99 million yuan last year.More tellingly, data from the Chinese banking regulator showed that the nonperforming loan ratio in the nation's banking sector edged up 0.1 percentage point in the fourth quarter from the third quarter, the first rise in the past six years.The regulator didn't give a reason, but the earnings reports from Chinese banks this week offered some cues: The property market might be the culprit.China Construction Bank said among the total, its nonperforming loans related to the real estate sector surged 20% over the same period.Minsheng Bank said the nonperforming ratio of its real estate financing businesses was 1.72%, well above its overall bad loan ratio of 0.63%.Home prices have been under pressure for about two years, but it's only now do we see a sign of it in banks' statements.The question is whether investors see a few more problem numbers down the road.In three years starting 2009, banks in China issued a total of 25 trillion yuan of

renminbi-denominated loans, with roughly 40% of the lending going to government-initiated infrastructure projects and the property sector.'The second quarter of this year will be one of the peak seasons for the repayment of property loans and local government borrowings.With a slowing economy, we can expect that higher nonperforming loans are on the cards,' GF Securities analyst Mu Hua said in a recent note.According to Noah Wealth Management, a Chinese financial service company, a total of 117.25 billion yuan of property trust products will be due this year, well above the 47.05 billion yuan last year, putting huge pressure on property developers' cash flows.Besides property, analysts say local government borrowings will present a bigger challenge to banks.Banking executives have estimated that a third of China's 10.7 trillion yuan government debt will be due this year and the next.Standard & Poor's analyst Liao Qiang said he believes Beijing will likely give some regulatory forbearance to local government debt to prevent a surge in banks' bad loans.'Nevertheless, property developers and manufacturers in industries with a supply glut will continue to face policy-induced refinancing uncertainties from time to time,' he said.Monday in Hong Kong, China Construction Bank Chairman Wang Hongzhang said he's optimistic about the bank's asset quality, given China's economic growth is likely to remain solid.'Nonperforming loan levels are controllable.Even though they are higher than before, the amount is small and [the rise] is likely to be temporary,' he said.Agence France-Presse/Getty Images

中资银行净利润去年创下新高，似乎并没有受到中国这一世界第二大经济体经济增速放缓的影响。这是否意味着，银行业可以免受经济下行的影响呢？

未必。

银行业的反应往往有一定的滞后性。只有在一段时期后，中国宏观经济形势的影响才会在银行的营收中有所体现。

以不良贷款为例。在下降趋势持续了几年之后，不良贷款的比例终于开始上升，虽然涨幅不大。按资产总量计算，中国最大的银行中国工商银行(Industrial & Commercial Bank of China Ltd.)的不良贷款去年第四季度增加了人民币38.2亿元（约合6.06亿美元），中国第二大银行中国建设银行(China Construction Bank Corp.)的不良贷款增加了人民币62.7亿元。中国银行(Bank of China Ltd.)的不良贷款在第四季度增加了13.9亿元。（在中国，不良贷款指的是变成坏账的几率在30%以上的贷款。）

规模较小银行的不良贷款水平也在增长。中国最大的非国有银行中国民生银行(China

Minsheng Banking Corp.)2011年不良贷款增加了人民币2亿元。兴业银行(Industrial Bank Co.)的不良贷款去年增加了人民币9,900万元。

更能说明这一问题的是，中国银监会的数据显示，中国银行业的不良贷款比例在第四季度较第三季度上升了0.1个百分点，这是该比例过去六年来首次上升。

银监会没有给出原因，但是中资银行本周发布的年报提供了一些线索：房地产市场可能是罪魁祸首。

中国建设银行表示，在该银行的所有不良贷款中，与房地产业有关的不良贷款同比上涨了20%。民生银行说，其房地产融资业务的不良贷款比例为1.72%，大大超过了其0.63%的总体不良贷款比例。

两年来住房价格一直在承受压力，但直到现在我们才在银行的年报中看到了相关迹象。问题是，投资者是否看到了更多问题数据出现的可能性。

从2009年到2011年这三年里，中资银行共发放了25万亿元以人民币计价的贷款，其中约有40%的贷款流向了政府主导的基建项目和楼市。

今年的第二季度将是房地产贷款和地方政府借贷的还款高峰期。广发证券(GF Securities Co.)分析师沐华在最近的一份报告中说，由于经济减速，我们预计可能出现更多的不良贷款。

中国的金融服务公司诺亚财富投资管理有限公司(Noah Private Wealth Management, 简称：诺亚财富)说，共有1,172.5亿元的房地产信托产品将会在今年到期，高于去年的470.5亿元，这给房地产开发商的现金流造成了巨大压力。

分析人士说，除了房地产，地方政府借的贷款将为银行带来更大的挑战。据一些银行高管估计，中国10.7万亿元的政府贷款中，有三分之一将在今明两年到期。

标准普尔(Standard & Poor)的分析师廖强说，中国中央政府可能会给予地方政府债务一定的宽限，以防不良贷款激增。他说，尽管如此，房地产开发商以及供应过剩行业的制造企业仍会不时地面临由政策引发的再融资不确定性。

中国建设银行董事长王洪章周一在香港说，考虑到中国经济很可能继续保持稳定增长，他对该银行的资产质量持乐观态度。他说，不良贷款的水平是可控的。即使是比以往有所增加，总量还是很小，而且增长很可能也是暂时的。