外文原文
Mining Electrical Equipments
Mining Electrical Equipments
Electrical apparatus and equipment used in mines excepting lighting equipment, fall into two classes, viz.:
(1)low-power units, such as signaling apparatus (bells, relays transformers and batteries),telephones, shot-firing apparatus(exploders)and pilot-circuit apparatus for use in remote-control systems.
(2)Normal power plant including motors, switchgear, controllers, etc.
There two classes of apparatus differ considerably in the means which can be to different kinds of tests before being certified for use in mines.
Intrinsic safety. Apparatus in class(1)can be rendered intrinsically safe; that is to say, it can be so constructed as to be incapable of giving rise to sparks or break flashes which will ignite an inflammable mixture of firedamp and air under any conditions likely to arise in practice.
To illustrate this, consider first the case of a signal bell and circuit operated by bare wires .Everyone will have observed that when such a bell is operated, sparks occur both at the trembler contacts of the bell itself and at point in the bare wires from which the signal is given. If an ordinary bell were used, such as those used for house signals, the sparks both at the bare-wire contact point would be capable of igniting a surrounding inflammable mixture .If, however, we limit the operating voltage and in addition incorporate within the bell some modification or device which reduces the intensity of the sparks produced, or “damps” the sparks, it is possible to make the sparks or break flashes so weak that they are incapable, in normal working, of igniting even the most easily ignited mixture of firedamp and air. Such an apparatus is said to be “intrinsically” safe and may be used in any position, even for use with bare-wire signaling. Intrinsic safety dose not imply that the break flash has been entirely eliminated, but that it has been so reduced intensity that danger of ignition even under the worst possible conditions that may be encountered, is reduced to the minimum if not entirely eliminated.
Flameproof Electrical Apparatus. Sparks from electric-pressure units already mentioned. They possess more energy, and unfortunately it is not possible to suppress or reduce these sparks to such an extent as to render them incapable of igniting an inflammable firedamp-air mixture. It may be taken for granted that in the absence of proper precautions, all sparks from such plant, motors, switchgear controllers, etc. will ignite gas, even when they are very small and are not very bright in appearance.
Therefore to avoid the danger of explosions arising from these sparks proper precautions must be adopted and in practice only apparatus which has been proved by tests to be safe and certified as flameproof is allowed to be used in coal-mines where danger from firedamp may arise.
At first sight it may appear that a sure way to prevent the sparks from electrical apparatus causing an explosion would be to enclose the apparatus in a strong gastight casing, which would not allow the explosive mixture to come into contact with the sparks, It is, however, almost impossible to make the casings of electrical equipment gastight and quite impossible to guarantee that they would remain so in use. The casings must be so made that they can be opened for inspection, testing and repair. This means that there must be joints between the casings and covers, and sooner or later firedamp, if present in the surrounding atmosphere, will find its way through the best of joints, however close fitting these may be made. Passage of air and gas in and ort of the casing occurs, not only as a result of diffusion which is always active, but also by what is known as “breathing”due t o differences in temperature. Thus, when apparatus is heated up, the air inside the casing expands, and some of it is forced out, whereas when the apparatus cools down again the air within contracts and air containing firedamp, if present, is sucked in from the outside.
Since, therefore, for various reasons firedamp may at some time or other be present in the atmosphere where the apparatus is to work and may find its way into the casing, and since we cannot prevent sparking inside the casing nor suppress the sparks sufficiently to prevent them igniting the firedamp, we must construct in such a way that flame cannot pass to the outside of the casing.
To ensure this the casing must be strong enough to withstand the force or pressure of
any ignition occurring within it, and must not have openings of any kind through which flame can pass.
Fortunately, it is possible to construct flameproof casings for all types of mining electrical apparatus without difficulty, but in order to ensure safety, numerous requirements must be met. These requirements are based on the results of scientific research and testing, and many of them refer to details of design and construction.
Explosion-proof equipment
Electrical design and construction for hazardous locations requires careful selection and installation of equipment and materials. All enclosures-motor frames, luminaire housings, cabinets for panelboards and switching devices, receptacle outlets, and conductor enclosures-must be suitable for use in the particular type of hazardous location.
Strict conformity to the provisions of the National Electrical Code and reference to the “Hazardous Location Equipment” list of the Underwriters’ Laboratories, Inc., can effectively minimize the hazards of such application.
The principal objective of all hazardous equipment design is to prevent any heat, arcs and sparks from electrical devices from igniting the highly combustible gases and particles which are normally present in areas classified as hazardous.
Classifications
Articles 500 to 517 of the National Electrical Code cover general and specific requirements on wiring in hazardous locations. The basic idea behind these requirements is that parts of electrical systems in or passing through areas where flammable gases, combustible dusts or ignitable fibers or flying are or may be present must be of such construction that arcs or sparks cannot be transmitted out of the equipment or conductor enclosures to cause ignition of any hazardous atmospheric mixture. In setting up its rules, the Code divides hazardous locations into three classes which cover the range of hazardous atmospheres, as follows;
CLASS 1 LOCATIONS-those in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.
Such locations are further subdivided according to the characteristics of the type of gas
or vapor which produces the hazardous atmospheric mixture .This breakdown is made for the purpose of testing and approving equipment for application in specific atmospheres. Underwriters’ Laboratories tests and approves Class 1 equipment for atmospheres-Group A, acetylene; Group B, hydrogen; Group C, ethyl-ether, ethylene or cycle-propane gases;Group, D, gasoline, naphtha, benzene,butane,propane,alcohol,acetone,lacquer solvent vapors or natural gas.
When a hazardous location has been determined as Class 1 and the group designation has been determined by the particular atmosphere, the location must then be identified as either Division 1 or Division 2.This further distinction indicates the degree of the hazard. Division 1 locations have hazardous concentrations of the gas or vapor continuously, intermittently or periodically under normal conditions. Division 2 locations are those in which the volatile liquids or gases are handled in closed containers or closed systems and are, therefore, less hazardous locations than Division 1.
CLASS II LOCATION-those where the presence of combustible dusts present a fire or explosion hazard. Based on the type of dust, equipment for such locations are further designated-Group E, metal dusts; Group F, carbon black, coal or coke dust; Group G, flour, starch or grain dust..
CLASS II, Division 1 locations are those where the dust is not in suspension but where it may collect on electrical equipment and produce a fire hazard.
CLASS III, LOCATION-those where easily ignitable fibers or flying are present but not likely to be suspended in the air in quantities sufficient to produces ignitable mixtures .In this class, Division 1 locations are those where ignitable fibers or materials producing combustible flying are handled, manufactured or used. Division 2 locations are those where such fibers are stored or handled. There are no group designations for Class III locations.
Application
Equipment used in Class I and Class II locations should be specifically designed and approved for both Class and Group of hazard. Such equipment should bear the Underwriters’Laboratories label, noting specific approval. This applies to lighting fixtures, motors, controllers, switches, circuit breakers, plugs, receptacles, panel boards and other
equipment.
For wiring in hazardous locations, rigid conduit of steel or aluminum may be used with threaded fittings as the only Code-approved raceway system in all hazardous areas. Such conduit provides required mechanical protection and contains internal explosions to prevent propagation of the flame to the hazardous atmosphere external to it. Fittings and junction boxes used with conduit systems must be “exp losion-proof” design in Class 1 locations; in Class locations, they must be “dust-ignition-proof” types.
Generally, seals are installed in conduits entering enclosures for switches or other devices which may produce arcs, sparks or high temperatures. And the seal in each conduit must be placed within 18 inches of the point of entrance of the conduit to the enclosure. A seal must also be installed in a conduit run where it passes from a Class I or Class II hazardous location into a non-hazardous area. To facilitate compliance withsealing requirements, some explosion-proof control devices and panelboards are made with integral seals, eliminating need for conduit seals.
Hazardous location luminaries are constructed to present entry of gas, vapor or dust into the lamp assembly. And their temperature of operation must not reach the ignition level for the particular atmosphere. Luminaries are labeled for their specific approved application. Some such units also incorporate integral seals.
中文翻译
矿山电气设备
矿山电气除照明设备外分两大类，即：
（1）矿用小功率设备，如通讯设备（信号铃、继电器）、电话、爆破设备（爆炸器）和在遥控系统中应用的控制电路设备；
（2）一般电源装置，包括电动机、开关装置、控制器等。
这两种设备在用于易燃环境的安全保障方式上差别很大，而且在获准用于煤矿前要进行不同的检试。
本质安全型电气设备。矿用小功率设备须具备内在安全性。也就是说，要如此制造设备使之在实际可能发生的任何情况下都不会产生点燃瓦斯气体的火花或电闪光。
为阐述这些，首先要考虑由裸线控制的信号铃和信号电路。可以观察到，当操纵信号铃时，在信号铃振动器触点和裸线上信号发出点都会产生火花。如果使用一般的信号铃，这样的火花能引燃沼气——空气混合物。然而，如果我们降低工作电压并降低火花或矿井瓦斯的密度，就会使这些火花不能引燃在正常工作时的沼气——空气混合物。据
说这种设备具有内在安全性，可用于任何地点，甚至可与裸线信号装置一起使用。这样的设备我们称之为本质安全型电气设备。本质安全并不意味着完全熄灭电路短路、断路或接地时产生的火花，而是它能降低点燃强度以至使在更恶劣环境下产生点燃的危险性降到最低。
隔爆型电气设备。从电源中产生的火花往往比上述提到的低压设备中产生的火花强度大。这些火花有更多的能量。但不幸的是，我们不能使这些火花降到一定范围，从而不能引燃沼气——空气混合物。我们可以想当然地认为，如果没有适当的预防措施，所有从电动机、开关控制等发出的火花都将引燃混合物，即使这些火花在表面上看起来很小。
因此，为了防止这些火花引起爆炸的危险，我们必须在实际应用中采取一些预防措施。事实上，只有试验证明安全并发给防爆证书的设备方可用于有瓦斯爆炸危险的煤矿上。
乍看起来，似乎阻止电火花引爆的可靠方法是将电器置于坚固且不透气的箱体中。此箱体将不允许电火花与爆炸性气体接触。然而要使电气设备外壳不透气并且保证正常工作，这是不可能的。箱体必须能够打开，以便检查、试验和维修。这就意味着：在箱体和盖子之间肯定有接缝，而且无论接合多么紧密，周围的瓦斯迟早都可能会穿过大部分接缝。空气、沼气出入箱体设备的通道，不仅是由于空气的扩散，还由于所谓的“呼吸”引起温度的不同。因此，当箱体设备被加热时，箱体内的气体膨胀，一些气体被挤出。然而，当箱体再次冷却时，空气又从外面细入箱体内。
因此，电气设备内部的爆炸性气体的爆炸是很难避免的。既然我们不能阻止箱体内出现火花，也不能充分抑制火花使之不点燃瓦斯，就必须这样制造箱体使火焰不致传到外面。
为满足上述要求，箱体外壳必须要足够坚固以至它能承受内部爆炸所产生的压力，并且在火焰经过的地方不能有任何缝隙。
幸运的是，控制所有类型的矿用电气设备防爆外壳是很有可能的，但是为了确保安全，还需要满足很多要求。这些要求是基于科学研究和试验的结果。许多要求涉及到设计和建设。
隔爆电气设备
危险位置的电力设计和建设，要求对其物资与设备进行精心的选择和安装。所有电机架、光源设备、配电板和开关控制柜、电源插座、导体设备必须符合在危险环境中的特殊应用。
严格按照国家电力规章和专人负责的实验室中提到的“危险地段设备”的预防措施，能够有效地减小比类设备在应用中的危险性。
所有电气设备设计的准则是：防止任何电气设备内部的热量、火花和电弧引燃周围环境中的易燃气体和经常在危险程度分类中出现的颗粒。
分类：
国家电力规章中第500条款至517条款包括了在危险位置布线的一般和特殊的要求。这些要求的基本观点是使电气设备内部的爆炸限制在机壳内部，而不致引起机壳外部的爆炸性气体混合物爆炸，为说明这些规则，国家电力规章中将危险场所分为如下三类：第I类场所：可燃性气体或是蒸汽在空气中所占比例足以引爆或点燃爆炸性混合物，这种场所根据产生危险气体混合物的气体或是蒸汽进行划分，这种分类目的是为了对电
气设备在具体场合的检验，专人负责的实验室将I类电气设备又分为A组（乙炔）；B 组（氢气）；C组（乙醚、乙烯或环丙烷气体）；D组（汽油、石脑油、丁烷、丙烷、乙醇、丙酮、有溶解能力的漆或天然气）。
当危险场所被定义为I类，组别名称被定义为特殊环境是，危险场所必须再划分为1级和2级这种进一步的划分表明危险的程度。1级场所是经常或断续放出爆炸性气体，是长时间保持其浓度超过爆炸下限的场合，或爆炸性气体以及可燃性气体有可能突出或喷出的危险场所。2级场所是爆炸性气体在密闭容器或密闭系统中，因此危险性比I级场所低。
第II类场所：易燃性尘粒的存在引起火灾危险和爆炸危险的场所。根据尘粒的类型，在此场所应用的电气设备又进一步分为E组（金属尘）；F组（碳黑、煤尘）；G组（面粉或淀粉尘粒）。
II类1级场所是那些尘粒并不悬浮但能在电气设备上聚集并能引起火灾危险的场所。
第III类场所：存在易燃纤维但不易悬浮在空中以至点燃爆炸性气体混合物的场所。在这类场所中，I级场所中易燃纤维或其他物质被处理、制造或应用。2级场所中这些纤维被储存或处理。第III类场所没有组别的划分。
应用
在I类和II类场所中使用的电气设备在类别和组别都应进行特殊的设计和核准。这些电气设备应该能承受专人负责实验的检验，并没有特殊的批准。这适用于照明设备、电动机、控制器、开关、断路器、插座、配电板和其它电器设备。
对在危险位置的布线而言，不易弯曲的钢管和铝管与链接配件一起使用，可以作为所有危险区域仅有的（电力规章）条款所准许的电缆管道系统。这样的电缆管道系统需要机械方面的保护。电气设备内部的爆炸应限制在机壳内部，而不致使火焰向外传播。在I类场所中所使用的接线盒应注有“隔爆”标志；而在II类场所中则应注有“防尘”标志。
国家电力规章详述了各种类别场所使用的电气设备、密封装置及布线方式。
在危险场所管道系统中使用密封装置是为了防止气体、蒸汽或火焰从电气系统
的一边通过管道进入另一边。这样的装置由在管道封闭导线周围的横截面上的化
合物提供。也能有效地在那一点封锁管道。
垫圈一般都安装在电缆管道接入开关或其它装置间隔处，而这些开关或装置很可能产生电弧、火花或高温。并且在每个管道的垫圈必须进入管道口18英寸。还必须能适应从I 类场所和II类场所到无危险场所的转换。为了达到上述要求，管道密封必须采用一些防爆控制装置。
危险地段的照明设备在制造时就具有防止气体、水蒸气或灰尘进入电灯装置的功能。而且它们的工作温度不能达到燃烧点。照明设备在它们的具体应用中有标志。这样的装置在整体密封装置中经常应用。
外文出处： 《Exploiting Software How to Break Code》By Greg Hoglund, Gary McGraw Publisher : Addison Wesley Pub Date : February 17, 2004 ISBN : 0-201-78695-8 译文标题： JDBC接口技术 译文： JDBC是一种可用于执行SQL语句的JavaAPI（ApplicationProgrammingInterface应用程序设计接口）。它由一些Java语言编写的类和界面组成。JDBC为数据库应用开发人员、数据库前台工具开发人员提供了一种标准的应用程序设计接口，使开发人员可以用纯Java语言编写完整的数据库应用程序。 一、ODBC到JDBC的发展历程 说到JDBC，很容易让人联想到另一个十分熟悉的字眼“ODBC”。它们之间有没有联系呢？如果有，那么它们之间又是怎样的关系呢？ ODBC是OpenDatabaseConnectivity的英文简写。它是一种用来在相关或不相关的数据库管理系统（DBMS）中存取数据的，用C语言实现的，标准应用程序数据接口。通过ODBCAPI，应用程序可以存取保存在多种不同数据库管理系统（DBMS）中的数据，而不论每个DBMS使用了何种数据存储格式和编程接口。 1．ODBC的结构模型 ODBC的结构包括四个主要部分：应用程序接口、驱动器管理器、数据库驱动器和数据源。应用程序接口：屏蔽不同的ODBC数据库驱动器之间函数调用的差别，为用户提供统一的SQL编程接口。 驱动器管理器：为应用程序装载数据库驱动器。 数据库驱动器：实现ODBC的函数调用，提供对特定数据源的SQL请求。如果需要，数据库驱动器将修改应用程序的请求，使得请求符合相关的DBMS所支持的文法。 数据源：由用户想要存取的数据以及与它相关的操作系统、DBMS和用于访问DBMS的网络平台组成。 虽然ODBC驱动器管理器的主要目的是加载数据库驱动器，以便ODBC函数调用，但是数据库驱动器本身也执行ODBC函数调用，并与数据库相互配合。因此当应用系统发出调用与数据源进行连接时，数据库驱动器能管理通信协议。当建立起与数据源的连接时，数据库驱动器便能处理应用系统向DBMS发出的请求，对分析或发自数据源的设计进行必要的翻译，并将结果返回给应用系统。 2．JDBC的诞生 自从Java语言于1995年5月正式公布以来，Java风靡全球。出现大量的用java语言编写的程序，其中也包括数据库应用程序。由于没有一个Java语言的API，编程人员不得不在Java程序中加入C语言的ODBC函数调用。这就使很多Java的优秀特性无法充分发挥，比如平台无关性、面向对象特性等。随着越来越多的编程人员对Java语言的日益喜爱，越来越多的公司在Java程序开发上投入的精力日益增加，对java语言接口的访问数据库的API 的要求越来越强烈。也由于ODBC的有其不足之处，比如它并不容易使用，没有面向对象的特性等等，SUN公司决定开发一Java语言为接口的数据库应用程序开发接口。在JDK1．x 版本中，JDBC只是一个可选部件，到了JDK1．1公布时，SQL类包（也就是JDBCAPI）
附录 科技译文： Numerical Control Numerical Control(NC) is a method of controlling the movements of machineComponents by directly inserting coded instructions in the form of numerical data(numbers and data ) into the system.The system automatically interprets these data and converts to output signals. These signals ,in turn control various machine components ,such as turning spindles on and off ,changing tools,moving the work piece or the tools along specific paths,and turning cutting fluits on and off. In order to appreciate the importer of numerical control of machines ,let’s briefly review how a process such as machining has been carried out traditionally .After studying the working drawing of a part, the operator sets up the appropriate process parameters(such as cutting speed ,feed,depth of cut,cutting fluid ,and so on),determines the sequence of operations to be performed,clamps the work piece in a workholding device such as chuck or collet ,and proceeds to make the part .Depending on part shape and the dimensional accuracy specified ,this approach usually requires skilled
附录一英文科技文献翻译 英文原文： Experimental investigation of laser surface textured parallel thrust bearings Performance enhancements by laser surface texturing (LST) of parallel-thrust bearings is experimentally investigated. Test results are compared with a theoretical model and good correlation is found over the relevant operating conditions. A compari- son of the performance of unidirectional and bi-directional partial-LST bearings with that of a baseline, untextured bearing is presented showing the bene?ts of LST in terms of increased clearance and reduced friction. KEY WORDS: ?uid ?lm bearings, slider bearings, surface texturing 1. Introduction The classical theory of hydrodynamic lubrication yields linear (Couette) velocity distribution with zero pressure gradients between smooth parallel surfaces under steady-state sliding. This results in an unstable hydrodynamic ?lm that would collapse under any external force acting normal to the surfaces. However, experience shows that stable lubricating ?lms can develop between parallel sliding surfaces, generally because of some mechanism that relaxes one or more of the assumptions of the classical theory. A stable ?uid ?lm with su?cient load-carrying capacity in parallel sliding surfaces can be obtained, for example, with macro or micro surface structure of di?erent types. These include waviness [1] and protruding microasperities [2–4]. A good literature review on the subject can be found in Ref. [5]. More recently, laser surface texturing (LST) [6–8], as well as inlet roughening by longitudinal or transverse grooves [9] were suggested to provide load capacity in parallel sliding. The inlet roughness concept of Tonder [9] is based on ??e?ective clearance‘‘ reduction in the sliding direction and in this respect it is identical to the par- tial-LST concept described in ref. [10] for generating hydrostatic e?ect in high-pressure mechanical seals. Very recently Wang et al. [11] demonstrated experimentally a doubling of the load-carrying capacity for the surface- texture design by reactive ion etching of SiC
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
毕业设计（论文）外文文献翻译 文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目： 文献、资料来源： 文献、资料发表（出版）日期： 院（部）： 专业： 班级： 姓名： 学号： 指导教师： 翻译日期： 2017.02.14
外文资料原文 Software Development Concepts and Design Methodologies During the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including: ?Inability to sufficiently understand complex problems ?Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs ?Inability to accurately estimate development time and operational costs ?Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment. Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes. Whereas early desig n methods addressed specific aspects of the
附录 INTEGRATION OF MACHINERY （From ELECTRICAL AND MACHINERY INDUSTRY）ABSTRACT Machinery was the modern science and technology development inevitable result, this article has summarized the integration of machinery technology basic outline and the development background .Summarized the domestic and foreign integration of machinery technology present situation, has analyzed the integration of machinery technology trend of development. Key word：integration of machinery ，technology，present situation ，product t，echnique of manufacture ，trend of development 0. Introduction modern science and technology unceasing development, impelled different discipline intersecting enormously with the seepage, has caused the project domain technological revolution and the transformation .In mechanical engineering domain, because the microelectronic technology and the computer technology rapid development and forms to the mechanical industry seepage the integration of machinery, caused the mechanical industry the technical structure, the product organization, the function and the constitution, the production method and the management system has had the huge change, caused the industrial production to enter into “the integration of machinery” by “the machinery electrification” for the characteristic development phase. 1. Integration of machinery outline integration of machinery is refers in the organization new owner function, the power function, in the information processing function and the control function introduces the electronic technology, unifies the system the mechanism and the computerization design and the software which constitutes always to call. The integration of machinery development also has become one to have until now own system new discipline, not only develops along with the science and technology, but also entrusts with the new content .But its basic characteristic may summarize is: The integration of machinery is embarks from the system viewpoint, synthesis community technologies and so on utilization mechanical technology, microelectronic technology, automatic control technology,
本科毕业论文(设计) 外文翻译 学院：机电工程学院 专业：机械工程及自动化 姓名：高峰 指导教师：李延胜 2011年05 月10日 教育部办公厅 Failure Analysis，Dimensional Determination And
Analysis，Applications Of Cams INTRODUCTION It is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed．Sometimes a failure can be serious，such as when a tire blows out on an automobile traveling at high speed．On the other hand，a failure may be no more than a nuisance．An example is the loosening of the radiator hose in an automobile cooling system．The consequence of this latter failure is usually the loss of some radiator coolant，a condition that is readily detected and corrected．The type of load a part absorbs is just as significant as the magnitude．Generally speaking，dynamic loads with direction reversals cause greater difficulty than static loads，and therefore，fatigue strength must be considered．Another concern is whether the material is ductile or brittle．For example，brittle materials are considered to be unacceptable where fatigue is involved． Many people mistakingly interpret the word failure to mean the actual breakage of a part．However，a design engineer must consider a broader understanding of what appreciable deformation occurs．A ductile material，however will deform a large amount prior to rupture．Excessive deformation，without fracture，may cause a machine to fail because the deformed part interferes with a moving second part．Therefore，a part fails(even if it has not physically broken)whenever it no longer fulfills its required function．Sometimes failure may be due to abnormal friction or vibration between two mating parts．Failure also may be due to a phenomenon called creep，which is the plastic flow of a material under load at elevated temperatures．In addition，the actual shape of a part may be responsible for failure．For example，stress concentrations due to sudden changes in contour must be taken into account．Evaluation of stress considerations is especially important when there are dynamic loads with direction reversals and the material is not very ductile． In general，the design engineer must consider all possible modes of failure，which include the following． ——Stress ——Deformation ——Wear ——Corrosion ——Vibration ——Environmental damage ——Loosening of fastening devices
使用高级分析法的钢框架创新设计 1．导言 在美国，钢结构设计方法包括允许应力设计法(ASD)，塑性设计法(PD)和荷载阻力系数设计法(LRFD)。在允许应力设计中，应力计算基于一阶弹性分析，而几何非线性影响则隐含在细部设计方程中。在塑性设计中，结构分析中使用的是一阶塑性铰分析。塑性设计使整个结构体系的弹性力重新分配。尽管几何非线性和逐步高产效应并不在塑性设计之中，但它们近似细部设计方程。在荷载和阻力系数设计中，含放大系数的一阶弹性分析或单纯的二阶弹性分析被用于几何非线性分析，而梁柱的极限强度隐藏在互动设计方程。所有三个设计方法需要独立进行检查，包括系数K计算。在下面，对荷载抗力系数设计法的特点进行了简要介绍。 结构系统内的内力及稳定性和它的构件是相关的，但目前美国钢结构协会（AISC）的荷载抗力系数规范把这种分开来处理的。在目前的实际应用中，结构体系和它构件的相互影响反映在有效长度这一因素上。这一点在社会科学研究技术备忘录第五录摘录中有描述。 尽管结构最大内力和构件最大内力是相互依存的（但不一定共存），应当承认，严格考虑这种相互依存关系，很多结构是不实际的。与此同时，众所周知当遇到复杂框架设计中试图在柱设计时自动弥补整个结构的不稳定（例如通过调整柱的有效长度）是很困难的。因此，社会科学研究委员会建议在实际设计中，这两方面应单独考虑单独构件的稳定性和结构的基础及结构整体稳定性。图28.1就是这种方法的间接分析和设计方法。
在目前的美国钢结构协会荷载抗力系数规范中，分析结构体系的方法是一阶弹性分析或二阶弹性分析。在使用一阶弹性分析时，考虑到二阶效果，一阶力矩都是由B1,B2系数放大。在规范中，所有细部都是从结构体系中独立出来，他们通过细部内力曲线和规范给出的那些隐含二阶效应，非弹性，残余应力和挠度的相互作用设计的。理论解答和实验性数据的拟合曲线得到了柱曲线和梁曲线，同时Kanchanalai发现的所谓“精确”塑性区解决方案的拟合曲线确定了梁柱相互作用方程。 为了证明单个细部内力对整个结构体系的影响，使用了有效长度系数，如图28.2所示。有效长度方法为框架结构提供了一个良好的设计。然而，有效长度方法的
I / 11 本科毕业设计外文翻译 <2018届） 论文题目基于WEB 的J2EE 的信息系统的方法研究 作者姓名[单击此处输入姓名] 指导教师[单击此处输入姓名] 学科(专业 > 所在学院计算机科学与技术学院 提交日期[时间 ]
基于WEB的J2EE的信息系统的方法研究 摘要：本文介绍基于工程的Java开发框架背后的概念，并介绍它如何用于IT 工程开发。因为有许多相同设计和开发工作在不同的方式下重复，而且并不总是符合最佳实践，所以许多开发框架建立了。我们已经定义了共同关注的问题和应用模式，代表有效解决办法的工具。开发框架提供：<1）从用户界面到数据集成的应用程序开发堆栈；<2）一个架构，基本环境及他们的相关技术，这些技术用来使用其他一些框架。架构定义了一个开发方法，其目的是协助客户开发工程。 关键词：J2EE 框架WEB开发 一、引言 软件工具包用来进行复杂的空间动态系统的非线性分析越来越多地使用基于Web的网络平台，以实现他们的用户界面，科学分析，分布仿真结果和科学家之间的信息交流。对于许多应用系统基于Web访问的非线性分析模拟软件成为一个重要组成部分。网络硬件和软件方面的密集技术变革[1]提供了比过去更多的自由选择机会[2]。因此，WEB平台的合理选择和发展对整个地区的非线性分析及其众多的应用程序具有越来越重要的意义。现阶段的WEB发展的特点是出现了大量的开源框架。框架将Web开发提到一个更高的水平，使基本功能的重复使用成为可能和从而提高了开发的生产力。 在某些情况下，开源框架没有提供常见问题的一个解决方案。出于这个原因，开发在开源框架的基础上建立自己的工程发展框架。本文旨在描述是一个基于Java的框架，该框架利用了开源框架并有助于开发基于Web的应用。通过分析现有的开源框架，本文提出了新的架构，基本环境及他们用来提高和利用其他一些框架的相关技术。架构定义了自己开发方法，其目的是协助客户开发和事例工程。 应用程序设计应该关注在工程中的重复利用。即使有独特的功能要求，也
沈阳工业大学工程学院 毕业设计（论文）外文翻译 毕业设计（论文）题目：工具盒盖注塑模具设计 外文题目：Friction , Lubrication of Bearing 译文题目：轴承的摩擦与润滑 系（部）：机械系 专业班级：机械设计制造及其自动化0801 学生姓名：王宝帅 指导教师：魏晓波 2010年10 月15 日
外文文献原文： Friction , Lubrication of Bearing In many of the problem thus far , the student has been asked to disregard or neglect friction . Actually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement. Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary. The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt. There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding, and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. To produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement . Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. As shown in figure ,starting friction is always greater than sliding friction . Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction. The friction caused by the wedging action of surface irregularities can be overcome
毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年
研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.doczj.com/doc/ee1896300.html,，niuzhiguo@https://www.doczj.com/doc/ee1896300.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.doczj.com/doc/ee1896300.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。
Section 3 Design philosophy, design method and earth pressures 3.1 Design philosophy 3.1.1 General The design of earth retaining structures requires consideration of the interaction between the ground and the structure. It requires the performance of two sets of calculations: 1）a set of equilibrium calculations to determine the overall proportions and the geometry of the structure necessary to achieve equilibrium under the relevant earth pressures and forces; 2）structural design calculations to determine the size and properties of thestructural sections necessary to resist the bending moments and shear forces determined from the equilibrium calculations. Both sets of calculations are carried out for specific design situations (see 3.2.2) in accordance with the principles of limit state design. The selected design situations should be sufficiently Severe and varied so as to encompass all reasonable conditions which can be foreseen during the period of construction and the life of the retaining wall. 3.1.2 Limit state design This code of practice adopts the philosophy of limit state design. This philosophy does not impose upon the designer any special requirements as to the manner in which the safety and stability of the retaining wall may be achieved, whether by overall factors of safety, or partial factors of safety, or by other measures. Limit states (see 1.3.13) are classified into: a) ultimate limit states (see 3.1.3); b) serviceability limit states (see 3.1.4). Typical ultimate limit states are depicted in figure 3. Rupture states which are reached before collapse occurs are, for simplicity, also classified and