Gears are vital factors in machinery. One of the first mechanism invented using gears was the clocks. In fact, a clock is little more than a train of gears.Considerable study and research have been made on gears in recent years because of their wide use under exacting conditions. They have to transmit heavier loads and run at higher speeds than ever before. The engineers and the machinists all consider gearing the prime element in nearly all classes of machinery.
齿轮在机械中占有极其重要的作用。第一个利用齿轮做成的机械装置就是钟表，事实上，它只不过是用了一系列的齿轮。对于它可以在严格的条件下的广泛使用，在齿轮上做了大量的学习和研究。相比过去，它们现在必须在更高的速度下传递更重的负荷。工程师和机器操纵工人都认为齿轮在几乎所有的机器的零件中占有首要的因素。
1. Spur gears
Spur gears are used to transmit power and rotary motion between parallel shafts. The teeth are cut parallel to the axis of the shaft on which the gears are mounted. The smaller of two gears in mesh is called the pinion and the larger is customarily Designated as the gear. In most applications, the pinion is the driving element whereas the gear is the driven element.
1.直齿圆柱齿轮
直齿圆柱齿轮用于平行轴之间传递力和回转运动，轮齿被切制成与安装齿轮的轴之轴线相平行。两啮合齿轮中较小的叫小齿轮，大的习惯上叫齿轮，在大多数情况下，小齿轮是主动轮，大齿轮叫从动轮。
2. Helical gears
Helical gears have certain advantages, for example, when connecting parallel shafts they have a higher load-carrying capacity than spur gear with the same tooth numbers and cut with the same cutter.
2．斜齿圆柱齿轮
斜齿圆柱齿轮具有特定的优点，比如，当连接平行轴的用相同刀具切削出来的并齿数相同的斜齿轮比直齿轮具有较高的承载能力。斜齿轮也能用于连接相互成任意角度的非平行轴。
Helical gears can also be used to connect nonparallel , non-intersecting shafts
at any angle to one another.
斜齿轮也能用于连接相互成任意角度的非平行轴。
The maximum gear ratio obtainable with a single pair of gears varies with the type of gear and the application. The following are approximate maxim a for the various type for average load conditions: spur, 8; parallel-shaft helical, 10; straight bevel , 6; spiral bevel, 8;hypoid , 12; and worm , 80. For lightly loaded, instrument, and positioning gears, these rations can be exceeded. Rations as high as 400 or higher can be obtained with gears that resemble tapered worms meshing with hypoid gear. For heavily loaded gear, the given rations may be so high that a reasonable gear size precludes a satisfactory pinion.
一对齿轮能获得的最大传动比随齿轮类型和应用的变化而变化，以下是各种类型的齿轮的平均载荷条件的近似最大化，直齿是8，平行轴斜齿轮是10，直齿锥齿是6，曲线齿锥齿轮8，准双曲面12，蜗轮蜗杆8，对于轻载荷和定位齿轮这些传动比被超出，类似于成锥形的蜗轮蜗杆，和准双曲面齿轮能够获得的传动比高达
400 或更高，如此高以至于00 的齿轮尺寸不可能令人满意。
Since the ratio in a single pair of gears is the quotient of the tooth number, and since there usually are limitations on both the minimum and maximum numbers of teeth on the available gears,it follows that the number of ratios obtainable in a single pair is limited. To enlarge the coverage it is necessary to use multiple pairs, or trains. The overall speed ratio in a train is the product of the ratios in each pair. In certain cases an exact ratio cannot be obtained with gears, but by using two or more parts, the desired ratio can be approximated to any degree of precision.
一对齿轮的传动比齿数的商，它们通常是限制在有效齿轮的最大和最小齿数之间，因此，一对齿轮获得的传动比是受限制的，为了扩大范围，用多级齿轮副或系列是必要的，在一个系列中，总速比是每对齿轮产生的传动比。
As a convenience for machine builders and users, packaged speed reducers, following an industry-accepted pattern , are manufactured in a wide variety of types,configurations , speed ratios, and capacities; these consist of a box or housing containing bearings, shafts, lubricant and shaft oil seals. Speed increasers are usually custom build.
在某种情况下，一个确切的传动比不能由齿轮副获得，但是用两对或更多对时，要求的传动比能达到精确等级，为了对机器制造者和使用者方便起见，各种整装式减速器，根据工业通用的试样被大量的多样化的类型的组合的速度比的生产制造，这些由箱子组成或给含有轴承轴润滑剂和轴油封装外罩增速器通常被定别。All speed reducers when operating continuously become hot because of friction in the teeth, in the lubricant, in the bearings, and in the oil seals. If the heat is generated at a faster rate than it can be dissipated to the atmosphere, the lubricant may deteriorate and the gear or bearing fail.
所有的减速器当被连续使用时，由于轮齿在润滑剂轴承和油封件的摩擦会变热，如果热量的产生在空气中散逸的速度还快的话，润滑剂不能损坏，并且轴承和齿轮失效。
Worm gear sets are widely used because of the many advantages obtained by their tooth action and load carrying capacity. A large speed reduction or a high increase of torque can be attained with the worm gear set. Compactness of design is easy to obtain with such a combination, Worm gear drives are quiet and vibration free.
蜗轮装置由于啮合作用和传递载荷能力获得的许多优点而被广泛应用，大量转矩的减速或增速装置由蜗轮装置完成，设计的紧凑，用这样一个结合体是容易得到的，蜗轮是平稳且无振动的。
A worm gear set consists of the worm, which is very similar to a screw, and the worm gear, which is a helical gear. The shafts upon which the worm and the gear are mounted are usually at right angels but not in the same plane. The usual practice is to have the worm drive the worm gear. With same ratios, it is possible to have a gear driver the worm. However, with large ratios, it is impossible for the gear to drive the worm.
一个蜗轮装置由蜗杆——非常类似于螺丝和蜗轮——一个斜齿轮组成的，安装蜗杆和蜗轮的轴通常相互垂直而不在同一平面中，通常习惯上使蜗杆驱动蜗轮。小的传动比，使一个齿轮驱动蜗杆是有可能的，但是，大的传动比，使一个齿轮驱动蜗杆是不可能的。
The worm can be made with either right-hand or left-hand thread. Also, like a screw, it
can be made with single, double, triple, or quadruple thread. A single-thread worm advances the worm gear a distance equal to pitch for each complete worm rotation. The distance advanced is called the lead. Thus, the pitch equals the lead for a single thread.
A double-threaded worm has a lead which is twice the pitch.
蜗杆可以被制成右螺纹或左螺纹，同样像螺丝一样，蜗杆可以被制成单、双螺纹，三重或四重螺纹，单螺纹的蜗杆推进蜗轮等节距前进来完成每个完整的蜗杆转动，间距的推进称为节距。因而节距等于单螺纹的螺距，双螺纹的蜗杆螺距是两倍的节距。
The geometry of a worm is similar to that of a power screw. Rotation of the worm simulates a linearly advancing involute rack The geometry of worm gear(sometimes called a worm wheel) is similar to that of a helical gear, except that the teeth are curved to envelop the worm. Sometimes the worm is modified to envelop the gear. This gives a greater area of contact, but requires extremely precise mounting.
蜗杆的几何形状类似于机械螺纹，蜗杆的转动与一个渐开线导轨直线移动是相仿的。蜗轮几何形状（有时被称为蜗轮）类似于斜齿轮，除了包围在蜗轮上的齿是弯曲的以外。有时把蜗杆齿制成包裹在蜗轮，这就提供了更大的接触面积，但安装精度要求更高了。
A rotary cam is part on a machine which mechanically changes cylindrical motion to straight-line motion. The cam, which is mounted on a shaft, is usually driven by a motor either applied directly to the cam shaft or connected by pulleys or
gears. The purpose of a cam is to transmit various kinds of motions to other parts of a machine.
一个转动的凸轮是机械的一部分，也就是用机械的方式使回转运动变为直线运动。凸轮被安装在轴上通常由直接用到凸轮轴或是由皮带轮或齿轮联结成的任一原动力驱动。凸轮的目的是传递各种各样的运动到机械的其他部分。Practically every cam must be designed and manufactured to fit special requirements. Though each cam appears to be quite different from the other, all the cams work in a similar ways. In each case, as the cam is rotated or turned, another part in contact with the cam, called a follower, is moved either left and right, up and down, or in and out. The follower is usually connected to other parts on the machine to accomplish the desired action. The direction the follower move depends upon the position of the framework which attaches the cam and follower to the machine. If the
follower loses contact with the cam, it will fail to work.
几乎每个凸轮必须被设计和制造以适合特殊的要求，虽然每个凸轮显现的十分不同于其他凸轮。但是所有的凸轮都以类似的方式工作。在任何情况下，与凸轮转动或旋转时，与凸轮接触的另一部分成为从动件，向左或向右，向上或向下，向里或向外移动。从动件通常联结机械的其他部分以完成要求的运动，从动件运动的方向取决于结构的位置也就是在机械中联结凸轮和从动轮。如果从动件与凸轮不接触，它将不能工作。
The faster the cam turns, the more rapid is the motion of the follower. The motion of the follower caused by rotating the cam is exactly the same for each complete turn of the cam.
凸轮旋转越快，从动轮的运动越迅速，从动件的运动是由凸轮转动导致的并且这
种运动与每个凸轮整个旋转运动是正好相反。
Belt drives offer a maximum of versatility as power transmission elements. They allow the designer considerable flexibility in location of driver and driven machinery,and tolerances are not critical as is the case with gear drives. Another advantage of belt drives is that they reduce vibration and shock transmission. Furthermore, belt drives are relatively quiet.
皮带传动装置作为传递动力的元件用途极广。这种装置使设计人员在确定主动机械与从动机械的位置时有相当大的灵活性，而且公差要求也不像齿轮传动装置那样严格。皮带传动另一个优点是可以减少振动及其传播。不仅如此，皮带传动噪声也比较小。
Large flat leather belts were in general use many years ago, when the usual practice was to use one large engine to driver several different pieces of machinery. Some leather belts are in use at this time as well as flat steel, rubber, plastic, and fabric belts. Light, thin flat belts are practical on high speed machinery where vibration may be a problem 用皮革制成的大的平皮带在许多年前曾用得很普遍，那时，通常是用一台大功率的发动机驱动好几台不同的机器。现在，除了平钢带、橡皮带、塑料带和布带外，一些皮革做的皮带还在使用。轻质薄型平皮带在高速机械上很实用，因为这里振动可能是一个问题。
V belts are probably the most common means of transmitting power between electric motor and driven machinery. Conventional V belts are made of rubber. Most often, both driver and driven pulleys lie in the same vertical plane, and the speed ration is constant. 三角皮带大概是在电动机与从动机械之间传递动力的最为普通的手段。普通的三角皮带用橡皮制造。通常，主动轮与从动轮位于同一个垂直面上，速比是恒定的。Smooth flat belt and V belts depend on friction on the pulleys and some slippage is Inherent in their operation. Therefore, speed ratios are not precise. Most heavy duty pulleys are made of cast iron or formed steel.
平皮带和三角皮带依靠在皮带轮上的摩擦进行传动，所以在传动中总是有一些滑动，因此，速比就不精确。大多数大的皮带轮是用铸铁和型钢制造的。
Note that the capacity of the belt drive is determined by the angle of wrap on the smaller pulley, and that this is particularly critical for drives involving pullets of greatly differing size,special closely together.
Screws have been used as fasteners for a long time . As indicated in the section on single machine, a screw acts with a wedging action and consists of a circular cylinder (or truncated cone) with a helical Groove in it. When used for fastening, all screws are provided with means for applying a torque(twisting moment) to them; this may consist of a square of hexagonal head for a wrench, a head with a slot or a cross-shaped recess for a screwdriver, a cylindrical head with a recess fitting a special wrench, or a slot or recess on one end fitting a screwdriver or special wrench and no head.
螺钉已经被用来作为一种长期有效的紧固件。如本章的机床剖视图，螺钉的功能类似于一种楔紧作用，由具有螺纹的圆柱体（或者圆锥体）组成。当用于固定作用时，所有的螺钉都提供了一种施加扭矩的方式，这些方式有用于扳手的等边六角形，用于改锥的一字槽或者十字槽，用于配合特殊扳手的圆头凹槽，或者甚至
没有螺钉头但配合特殊改锥或特殊扳手的槽或凹坑。
Screws with screwdriver slots have heads of several shapes, such as flat, oval round, and fillister(cylindrical with a round top). Wood screws are tapered, and self-tapping screws have tapered ends and a variety of special points. The latter are usually hardened and cut or form a mating internal thread when screwed into the proper size hole.Screws with hexagonal heads are usually known as cap screws . Screws with other types of heads are also known as cap screws in the larger sizes and as machine screws in the small sizes. All of these screws are used to clamp machine parts together when one of the parts has an internal thread. If neither part is threaded ，a bolt must be used: this consist of screw with a hexagonal head, a Nut (hexagonal ring with an internal thread), and usually a washer(flat 扁ring).
带有六角形顶端的螺钉通常称为有头螺钉。这类螺钉用于当零件之一有内螺纹时把机器的零件加紧在一起。如果零件上未切出螺纹，则必须使用螺栓。螺栓由带有六角形顶端的螺钉、螺母（是一个有内螺纹的六角环）、通常还有一个垫圈组成。
In operation, shafts are subjected to a shearing stress , whose magnitude depends on the torque and the dimensions of the cross section. This stress is a measure of the resistance that the shaft material offers to the applied torque. All shafts that transmit a torque are subjected to torsional shearing stress .
轴在转动时承受剪应力，其大小取决于扭转和断面的尺寸。这个剪应力是轴的材料对作用扭矩所产生的抗力的一种量度。所有传递扭矩的轴都承受扭转剪应力。In addition to the shearing stresses, twisted 扭曲shafts are also subjected to shearing distortions. The distorted state is usually defined by the angle of twist per unit length, i.e., the rotation of one cross section of a shaft relative to another cross section at a unit distance from it.
轴的某一截面相对于间隔一个单位长度的另一截面的旋转角度。除剪应力之外，传递扭转的轴还会产生剪切变形。扭转的状态通常用每单位长度的扭转角来表示，
即用轴的某一截面所转过的角度来表示。
A coupling is a device for connecting the ends of adjacent shafts. In machine construction, couplings are used to effect a semipermanent connection between adjacent rotating shafts. The connection is permanent in the sense that it is not meant to be broken during the useful life of the machine, but it can be broken and restored in an emergency or when worn parts are replaced.
联轴器是一种联接两根相邻轴末端的装置。机械构件中，联轴器可以用来实现相邻两根旋转轴的半永久性联接。在机器的正常使用周期内，联轴器通常不必拆开，在这个意义上可以说联轴器的联接是永久性的，而在紧急情况下或者需要更换已磨损的零件时，可先把联轴器拆开并重新联接上。
There are several types of shaft couplings; their characteristics depend on the purpose for which they are used. If an exceptionally long shaft is required for a line shaft in a manufacturing plant or a propeller\shaft on a ship, it is made in sections that are coupled together with rigid couplings. A common type of rigid coupling consists of two mating radial flanges(disks) that are attached by key-driven hubs to the ends of adjacent shaft sections and bolted together through the flanges to form a rigid connection.
Alignment of the connected shafts is usually effected by means of a rabbet joint on the face of the flanges, i.e., a short cylindrical projection on the face of one flange fits snugly in a circular recess on the face of the other flange。
联轴器有几种类型，其特性随其用途而定。如果制造厂中或者船舶的螺旋桨需要一根特别长的轴时，可以分段制造，然后采用刚性联轴器将这些轴联接起来。常用的刚性联轴器包括两个匹配的径向法兰（盘），他们是通过靠键传动的轮毂来连接到相邻两轴的两端，然后用螺栓穿过法兰联接起来形成了刚性联接。相互联接的两轴是靠法兰面上的槽口来对准的，也就是说，在其中一个法兰面上的短圆柱上的凸起部分与另一个法兰面上的圆形凹进部分相互紧贴。
In connecting shafts belonging to separate devices (such as an electric motor and a gear-box), precise aligning of the shafts is difficult and a flexible coupling is used. This coupling connects the shafts in such a way as to minimize the harmful effects of shaft misalignment.Flexible couplings also permit the shafts to deflect under their separate systems of loads and to move freely (float) in the axial direction without interfering with one another. Flexible couplings can also serve to reduce the intensity of shock loads and vibrations transmitted from one shaft to another.
在把两个属于不同设备（如电机和变速箱）的轴联接起来时，要把这些轴精确对准是很困难的，因此可以采用弹性联轴器。采用这种联轴器联接两轴时，可以把由于轴联接中轴线不重合所造成的损害降到最小。弹性联轴器还可允许被联接的轴在各自载荷系统中偏斜和在轴向上自由移动（浮动），而不相互干扰。弹性联轴器还能用来减小从一根轴传到另一根轴的冲击载荷和振动强度。
A clutch is a device for quickly and easily connecting or disconnecting a rotatable shaft and a rotating coaxial[kEu5AksEl] shaft. Clutches are usually placed between the input shaft to a machine and the output shaft from the driving motor, and provide a convenient means for starting and stopping the machine and permitting the driver motor or engine to be started in an Unloaded state.
离合器是一个用来使从动轴与位于同一轴线上的主动轴进行快速和顺利的联接或脱开的装置。离合器通常位于机器的输入轴和驱动电机的输出轴之间，以提供一个方便地启动和停止机器的手段，并使得
驱动电机或发动机在无荷载的状态下启动。
The rotor (rotating member) in an electric motor has rotational inertia, and a torque is required to bring it up to speed when the motor is started. If the motor shaft is rigidly connected to a load with a large rotational inertia, and the motor is started suddenly by closing a switch, the motor may not have sufficient torque capacity to bring the motor shaft up to speed before the windings in motor are burned out by the excessive current demands. A clutch between the motor and the load shafts will restrict the starting torque on the motor to that required to accelerate the rotor and parts of the clutch only.
电机中的转子有转动惯量，当电机启动时需要一个转矩带动其运转。如果电动机的轴与具有很大转动惯量的负载刚性地联接在一起，当合上开关使电动机突然启动时，有可能在电动机没有来得及产生足够的扭矩，使电动机的轴达到应有的转速之前，电动机内的线圈就会因为过大的电流而被烧毁。电机和负载轴之间的离合器会限制电机的启动转矩只到所需要的加速转子和离合器部件的数值。
On some machine tools, it is convenient to let the driving motor run continuously and to start and stop the machine by operating a clutch. Other machine tools receive the power
from belts driven by pulleys on intermediate shafts that are themselves driven by belts from long line shafts that
serve a group of machine. Two pulleys that can be connected to the intermediate shaft by clutches, and driven in opposite directions by open and crossed belts from the line shaft, can provide forward and reverse rotation for the machine.
在某些机床上，通过操作离合器使驱动电机连续运转、启动和停止是非常方便的。其他机床上，机床是通过皮带获得动力，这些皮带是由中间轴上的滑轮来驱动，而中间轴又是通过总轴上的皮带来驱动，驱动这些中间轴的总轴同时还驱动其他的机器。两个滑轮可以通过离合器联接到中间轴上，通过总轴的开口式或者交叉式皮带驱动使得两滑轮以相反的方向转动，同时还能为机床提供正向和反向转动。
Basically, brakes are devices for controlling the flow of motion in machine, and in this respect they resemble clutches; clutches start the flow while brakes arrest it.Before the engagement of a clutch or a brake, one of the two members in the device is moving while the other is stationary; after the engagement of a clutch both members are moving at the same speed,while after the application of a brake the moving member is either slowed down or stationary. In both cases the desired effects are produced by devices that are so alike,structurally, that they can sometimes serve in either capacity.
基本上，制动器是一种控制机器中运动部件运动状态的装置，在这个方面，它与离合器类似，离合器激发运动，而制动器阻止其运动。在离合器或者制动器啮合之前，连接的两个部件中其中一个在移动而另外一个保持不动，在离合器啮合后，两个部件就以相同的速度移动，但使用制动器后，移动的部件要么减速下来，要么静止不动。不论哪种情况，由制动器或者离合器在结构上产生的效果如此相似，以至于他们有时可以执行任意一种功能。
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）
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
附录1：外文资料翻译 A1.1外文资料题目 26.22 接地故障电路开关 我们目前为止报道的接地方法通常是充分的, 但更加进一步的安全措施在某些情况下是必要的。假设例如, 有人将他的手指伸进灯口（如Fig.26.45示）。虽然金属封入物安全地接地, 但那人仍将受到痛苦的震动。或假设1个120V 的电炉掉入游泳池。发热设备和联络装置将导致电流流入在水池中的危害，即使电路的外壳被安全地接地，现在已经发展为当这样的事件发生时，设备的电源将被切断。如果接地电流超过5mA ，接地开关将在5 ms 内跳掉，这些装置怎么运行的？ 如Fig.26.46所示，一台小变流器缠绕上导线 ，第二步是要连接到可能触发开合120 V 线的一台敏感电子探测器。 在正常情况下流过导体的电流W I 与中性点上的电流N I 准切的相等，因此流经核心的净潮流(N W I I -)是零。 结果，在核心没有产生电流，导致的电压F E 为零，并且开关CB 没有动作。 假设如果某人接触了一个终端(图Fig.26.45示)，故障电流F I 将直接地从载电线漏到地面，这是可能发生的。如果绝缘材料在马达和它的地面封入物之间断开，故障电流也会被产生。在以下任何情况下，流经CT 的孔的净潮流等于F I 或L I ，不再是零。电流被产生，并且产生了可以控制CB 开关的电压F E 。 由于5 mA 不平衡状态只必须被检测出，变压器的核心一定是非常有渗透性的在低通量密度。 Supermalloy 是最为常用的，因为它有相对渗透性典型地70000在通量密度仅4mT 。 26.23 t I 2是导体迅速发热的因素 它有时发生于导体短期内电流远大于正常值的情况下，R I 2损失非常大并且导体的温度可以在数秒内上升几百度。例如，当发生严重短路时，在保险丝或开关作用之前，会有很大的电流流过导体和电缆。 此外，热量没有时间被消散到周围，因此导体的温度非常迅速地增加。 在这些情况下什么是温度上升？ 假设导体有大量m ，电阻R 和热量热容量c 。 而且，假设电流是I ，并且那它流动在t 少于15秒期间。 在导体上引起的热 Rt I Q 2= 从Eq.3.17，在功率一定的情况下我们可以计算导体上升的温度差：
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。
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
中文翻译 STC89C52处理芯片 电气工程的研究和解决方案中心（ceers） 艾哈迈德为吉.波特 首要性能： 与MCS-51单片机产物兼容、8K字节在系统可编程视频存储器、1000次擦拭周期，全静态操作：0Hz~33Hz、三级加密程序存储器，32个可编程I/O接口线、三个16位定时器（计数器），八个中断源、低功能耗空闲和掉电模式、掉电后间断可唤醒，看门狗定时器、双数值指针，掉电标示符。 关键词：单片机，UART串行通道，掉电标示符等 前言 可以说，二十世纪跨越了三个“点”的时代，即电气时代，电子时代和现已进入的电脑时代。不过，这种电脑，通常指的是个人计算机，简称PC机。还有就是把智能赋予各种机械的单片机（亦称微控制器）。顾名思义，这种计算机的最小系统只用了一片集成电路，即可进行简单的运算可控制。因为它体积小，通常都是藏在被控机械的内部里面。它在整个装置中，起着有如人类头脑的作用，他出了毛病，整个装置就会瘫痪。现在，单片机的种类和适用领域已经十分广泛，如智能仪表、实施工控、通讯设备、导航系统、家用电器等。各种产品一旦用上了单片机，就你能起到产品升级换代的功效，常在产品名称前冠以形容词——“智能型”，如智能洗衣机等。接下来就是关于国产STC89C52单片机的一些基本参数。 功能特性描述: STC89C52单片机是一种低功耗、高性能CMOS8位微控制器，具有8K在系统可编程视频播放存贮器使用高密度非易失性存储器技术制造，与工业80C51 产物指令和引脚完全兼容。片上反射速度允许程序存储器在系统可编程，也适用于常规的程序编写器。在其单芯片上，拥有灵敏小巧的八位中央处理器和在线系统可编程反射，这些使用上STC89C52微控制器为众多嵌入式的控制应用系统提供高度矫捷的、更加有用的解决方案。STC89C52微控制器具有以下的标准功效：8K字节的反射速度，256字节的随机存取储存器，32位I/O串口线，看门狗定时器，2个数值指针，三个16 为定时器、计数器，一个6向量2级间断结构，片内晶振及钟表电路。另外，STC89C52可降至0HZ静态逻辑操作，支持两种软件可选择节电模式、间断继续工作。空闲模式下，CPU停止工作，允许RAM、定时器/计数器、串口、间断继续工作。掉电保护体式格局下，RAM内容被生成，振动器被冻结，单片机一切的工作停止，直到下一个间断或者硬件复位为止。8位微型控制器8K字节在系统中可编程FlashSTC89C52.。
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
Optimum blank design of an automobile sub-frame Jong-Yop Kim a ,Naksoo Kim a,*,Man-Sung Huh b a Department of Mechanical Engineering,Sogang University,Shinsu-dong 1,Mapo-ku,Seoul 121-742,South Korea b Hwa-shin Corporation,Young-chun,Kyung-buk,770-140,South Korea Received 17July 1998 Abstract A roll-back method is proposed to predict the optimum initial blank shape in the sheet metal forming process.The method takes the difference between the ?nal deformed shape and the target contour shape into account.Based on the method,a computer program composed of a blank design module,an FE-analysis program and a mesh generation module is developed.The roll-back method is applied to the drawing of a square cup with the ˉange of uniform size around its periphery,to con?rm its validity.Good agreement is recognized between the numerical results and the published results for initial blank shape and thickness strain distribution.The optimum blank shapes for two parts of an automobile sub-frame are designed.Both the thickness distribution and the level of punch load are improved with the designed blank.Also,the method is applied to design the weld line in a tailor-welded blank.It is concluded that the roll-back method is an effective and convenient method for an optimum blank shape design.#2000Elsevier Science S.A.All rights reserved. Keywords:Blank design;Sheet metal forming;Finite element method;Roll-back method
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/9a15770840.html,，niuzhiguo@https://www.doczj.com/doc/9a15770840.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/9a15770840.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。
外文文献： The Intelligent Building One of the benefits of the rapid evolution of information technology has been the development of systems that can measure, evaluate, and respond to change。An enhanced ability to control change has sparked developments in the way we design our physical environment, in particular, the buildings in which we work。As a result, we are witnessing significant growth in the area of "Intelligent Buildings"--buildings that incorporate information technology and communication systems, making them more comfortable, secure, productive, and cost-effective What is an Intelligent Building? An Intelligent Building is one equipped with the telecommunications infrastructure that enables it to continuously respond and adapt to changing conditions, allowing for a more efficient use of resources and increasing the comfort and security of its occupants。An Intelligent Building provides these benefits through automated control systems such as: heating, ventilation, and air-conditioning (HVAC)；fire safety；security；and energy/lighting management。For example, in the case of a fire, the fire alarm communicates with the security system to unlock the doors。The security system communicates with the HVAC system to regulate the flow of air to prevent the fire from spreading。 What benefits do Intelligent Buildings offer their owners and occupants? The introduction in the workplace of computers printers photocopiers, and fax machines has increased indoor pollution。Electrical and telecommunications facilities in office buildings are under pressure to satisfy the demands created by the rapid growth of computer and networking technologies。These factors have a definite impact on productivity. New technology can be used to create Intelligent Buildings that address these problems by providing a healthier, more productive, and less energy-intensive work environment。As these are critical factors for business