第一单元应力与应变
That branch of scientific analysis which motions, times and forces is called mechanics
and is made up of two parts, statics and dynamics.
研究位移、时间和力运动乘力是科学分析法的一个分歧，被称作力学，力学由两大部
分组成，静力学和动力学。
For example, if the force operating on a sleeve bearing becomes too high, it will squeeze out the oil film and cause metal-to-metal contact, overheating and rapid failure of the bearing.
例如：如果止推轴承上的作用力过大的话，会挤出油膜，引起金属和金属之间的相互接触，轴承将过热而迅速失效。
Our intuitive concept of force includes such ideas as place of application, direction, and magnitude, and these are called the characteristics of a force.
力的直观概念包括力的作用点、大小、方向，这些被称为力的三要素。
All bodies are either elastic or plastic and will be deformed if acted upon by forces. When the deformation of such bodies is small, they are frequently assumed to be rigid, i.e., incapable of deformation, in order to simplify the analysis.
所有的物体既可以是弹性的也可以是塑性的，如果受到力的作用就产生变形。当变形很小的时候它们被假设成刚体，也就是不产生变形,以此来简化分析。
The rigid-body assumption cannot be used in internal stresses and strains due to the applied forces to be analyzed. Thus we consider the body to be capable of deforming.
刚体假设不能应用于内应力和内应变的分析，所以在实际力的分析时，要考虑物体的形变。If all the forces acting on a particle are balanced, the particle will either remain at rest or will continue to move in a straight line at a uniform velocity.
如果作用在质点上所有的力是平衡的，质点将会保持静止或做做匀速直线运动。
第二单元材料的强度与塑性
A tensile test consists of slowly pulling a sample of material with a tensile load until it breaks. The ends of tensile specimens are usually enlarged to provide extra area for grip-ping and to avoid having the sample break where it is being gripped.
拉伸试验包括慢慢加载拉伸载荷直到断裂。拉伸试件两端加粗为了提供装夹区域和避免试件断裂。
The usual manner of conducting the test is to deform the specimen at a constant speed. For example, in the universal testing machines, the motion between the fixed and moving crossheads can be controlled at a constant speed.
通常进行试验的方法就是使试件以恒定速度发生变形。例如，在万能拉伸试验机上，固定端和移动的十字滑块之间的变形是以恒定速度进行的。
The load that must be applied to enforce this displacement rate varies as the test proceeds. This load F may be divided by the cross-sectional area A to obtain the stress in the specimen at any time during the test.
随着实验的进行，用来产生位移的载荷是随位移的变化而变化。在实验中，载荷F除以横截面积A可以得到任意时刻点的应力。
However actual measurement of ΔL is preferable where this is feasible. Stress and st rain based on the initial (undeformed) dimensions, Ai and Li, are called engineering stress and strain.
然而，在可行的位置上ΔL的实际测量是更可取的，基于原始尺寸Ai和Li的应力和应变称
为工程应力和工程应变。
Ductile and brittle materials behave differently in compression test as well. The compression test is conducted on short cylindrical specimens placed between parallel plates.塑性和脆性材料在压缩试验中表现的特性是不相同的。压缩试验是把短圆柱形试件放在两平行平板之间进行的。
The compression test diagram for these materials retains the qualitative features of the tension test diagram. The ultimate compressive strength of a brittle material is determined in the same way as in tension.
材料压缩试验图保持了拉伸试验图性能上的特征。脆性材料的最大压缩强度与最大拉伸强度得到的方法相同。
第三单元轴设计
Virtually all machines contain shafts. The most common shape for shafts is circular and the cross section can be either solid or hollow (hollow shafts can result in weight savings).
几乎所有的机器都有轴，最常用的外形是圆形的，横截面是空心的或实心的圆形截面（空心轴可以减少重量）。
A shaft must have adequate torsional strength to transmit torque and not be overstressed. It must also be torsionally still enough so that one mounted component does not deviate excessively from its original angular position relative to a second component mounted on the same shaft.
一个轴必须有足够的扭转强度来传递扭矩而不会破坏，同样也必须有足够的扭转刚度，这样安装轴就不能过度偏离相对于安装在同一轴上第二个零件的原始位置。
Shafts are mounted on bearings and transmit power through such devices as gears, pulleys, cams and clutches. These devices introduce forces which attempt to bend the shaft; hence, the shaft must be rigid enough to prevent overloading of the supporting bearings.
轴安装在轴承上通过齿轮，滑轮，凸轮和离合器这些装置传递力。这些装置可以产生使轴弯曲的力，所以轴必修有足够的刚性防止支撑轴承的过载。
In addition, the shaft must be able to sustain a combination of bending and torsion and bending.
另外，轴必须能承载弯扭组合的载荷，因此，这样就必须考虑弯扭组合的等效载荷。Components such as gears and pulleys are mounted on shafts by means of key. The design of the key and the corresponding keyway in the shaft must be properly evaluated.
齿轮和滑轮构件是用键的方式连接在轴上的，键和对应的键槽的设计必须进行估算。Another important aspect of shaft design is the method of directly connecting one shaft to another. This is accomplished by devices such as rigid and flexible couplings.
轴设计的另一个重要方面是直接连接两轴，通过刚性和柔性的联轴器装置来实现。
第四单元Spur Gears齿轮
Pressure angles for spur gears are usually 14.5 or 20 degrees, although other values can be used. Meshing gears must have the same pressure angles.
直齿轮的压力角通常为14.5°或20°，另外也使用其它的角度，啮合齿轮必须具有相同的压力角。
The shape of the space between gear teeth on the gear as well as tooth module, so most gear manufacturing methods generate the tooth flank instead of forming.
齿轮轮齿之间齿槽的形状是复杂的，并且随着齿的数目和模数变化而变化，因此大多数齿轮的加工方法是展成齿腹齿廓而不是齿形成形加工。
Worm gears are used where high ratios are desired and where the shafts are nonintersecting and at right angles.
蜗杆蜗轮应用于传动比大而且两轴不相交但相互垂直的情况下。
It has the great advantage that the cutting tool is a simple rack with ( nearly ) straight sided teeth which can easily be ground accurately.
这种方法有很大的优势，切削工具是一个简单的带有直齿边的齿条
Modern shapers cutting car gears can run at 2000 cutting per minute. The shape of the cutter is roughly the same as an involute gear but the tips of the teeth are rounded.
现代切削汽车的成型器齿轮转速可达每分钟2000转，齿刀形状与渐开线大致相同，但齿顶是圆形的。
Bevel gears are often used when two shafts are at right angles to each other and their centerline extensions intersect; however, some bevel gears are at angles other than 90 degrees.
圆锥齿轮一般应用于相互垂直的两轴或两个中心线延长线的相交轴中，也可用于不垂直的两轴中。
第五单元cams 凸轮
The purpose of any cam is to produce a displacement of its follower; a secondary follower is often used to produce additional displacement in another location.
使用凸轮的目的是使从动件产生位移，次级从动件在另一位置产生附加运动。
The relative vertical position of point A with respect to B needs to be raised if the reaction value at B is excessive.
如果B点的作用力过大，A点相对B点的相对垂直位置必须被提高。
In general, the follower is considered to be the part that comes in contact with the cam profile. However, when a secondary follower is used, the motion of the secondary follower is dictated by that of the primary follower.
总的来说，从动件是与凸轮轮廓相接触的零件，然而，当用次级从动件时，次级从动件的运动就需通过主要从动件来实现。
The simplest type of follower is the reciprocating type that merely moves up and down ( or in and out ) with the rotation of the cam; the centerline can be either collinear with the cam centerline or offset form it.
最简单的从动件就是随着凸轮的转动而仅做上下（或进出）运动的从动件，其中心线可与凸轮中心共线，也可与之偏离。
Fasteners are devices which permit one part to be joined to a second part and, hence, they are involved in almost all designs.
紧固件是一种连接一个部分和另一个部分的装置，因此，它涉及到几乎所有的设计。Springs are mechanical members which are designed to give a relatively large amount of elastic deflection under the action of an externally applied load.
弹簧是一种被设计于在外力作用下产生相对弹性变形较大的机械构件
第七章：砂型铸造
1.The first stage in the production of sand casting must be the design and manufacture of a
suitable pattern. Casting pattern has to be made larger than the finished casting size to allow for the shrinkage that takes place during solidification and cooling.
在型砂铸造生产中，第一阶段是必须设计和制造合适的模型，考虑到铸件在凝固和冷却期间产生的收缩铸件模型的尺寸要比铸件的尺寸大。
2.If a hollow casting is to be made the pattern will include extension pieces so that spaces to accept the sand core are molded into the sand. These additional spaces in the mold are termed core prints.
如果铸造空心铸件时模型上包含伸长杆便于在砂中放置砂芯的空间称为型芯座。
3.Sand molds for the production of small and medium-sized castings are made in a molding box. The mold is made in two or more parts in order that the pattern may be removed.
中小型尺寸的铸件砂型是在一个砂箱中制造，砂型由两部分或更多部分组成，以利于模型的顺利取出。
4.This process of filling and ramming may be done by hand but mold production is automated in a large foundry with the mold boxes moving along a conveyor, firstly to be filled with sand from hoppers and then to pass under mechanical hammers for ramming.
填充和夯实的过程可以手工完成，但在大型铸造中砂型的制造是自动完成的，砂箱随着传送带移动，首先被料斗中的砂子填满，然后通过机械锤时被打实。
5.The risers should coincide with the highest points of the mold cavity so that the displaced air can readily escape from the mold. The sizes of risers should be such that the metal in them does not freeze too rapidly.
冒口应该与型腔的最高点相连接，使得进入的空气可以容易的从模型中溢出，冒口的尺寸应该足够大使模型中金属不会太快凝固。
6.When the metal that has been poured into a sand mold has fully solidified, the mold is broken and the casting is removed. The casting still has the runner and risers attached to it and there will be sand adhering to portions of the surface.
当熔的金属被倾倒到砂型内并充分凝固以后，砂型将被打破取出铸件，铸件上依然带有横浇口和冒口并且依然有砂子粘在表面。造是自动完成的，砂箱随着传送带移动，首先被料斗中的砂子填满，然后通过机械锤时被打实。
第8课锻造
1. Forging means the shaping of metal by a series of hammer blows, or by slow application of pressure. The simplest example is a blacksmith’s forging of a hot piece of metal by hammering the work-piece on an anvil.
铸造是通过一系列的锤打或是在缓慢的加载压力的场合使金属成型的一种方法，最简单的实例就是热的金属的自由锻，即通过铁砧上锤打锻件。
2. Heavy smith’s forging is fundamentally similar, dif fering only in the scale of the operation. The work-piece may be an ingot of 100 tons and the deforming force provided by a massive forging hammer, but the whole process is controlled by the master smith, who decides each time where, and with what force, the blow should take place.
重型自由锻和自由锻基本相似，仅在操作的规模上有所不同，锻件可以是一个100吨的铁块，锻压力由一个巨大的锻锤提供，但是整个锻造过程由操作者控制。他来决定什么时候用多大力打到什么地方。
3. Forging operations may be carried out using either forging hammers or forging presses. With a press, as opposed to a hammer, pressure is slowly applied and plastic deformation
tends to occur fairly uniformly throughout the material.
锻造操作者既可以用锻锤也可以用锻压力来实现操作，用锻压力和锻锤相反，在压力缓慢作用使整个均匀杆产生塑性变形的趋势。
4. Forging hammers are of two basic types with the large hammer either dropping on to the work-piece accelerated by gravity alone or, as in the steam hammer, accelerated by both gravity and steam pressure.
锻锤有两种基本类型，既可以用很大的锤子通过作用在工件上也可以用蒸汽压力作用在工件上或者是两者结合。
5. Smith’s or open-die forging is used for making very large forgings or when the number of forgings of a particular design is small. Open-die forging is also used to preform metal prior to final shaping by means of closed-die forging.
自由锻或开模锻用于制造大型的锻件或者特殊设计的小锻件，开模锻用于预成型金属，在最终金属成型之前通常使用闭模锻。
6. Closed-die forging involves the use of accurately machined die blocks. The capital cost of a pair of die blocks is high, but this is allowable when it is required to make forgings to close dimensional tolerances and in large quantity, as would be the case for, say, connecting rods for the engine of a popular car.
闭模锻包括精确的机械加工的模具，一对模具的成本很高，但是只适用于大批量生产和小的公差要求的锻件，例如，汽车发动机的连杆就是一个典型的例子。
第九章电弧焊
1.Arc welding in one form or another is the most widely used form of welding .the electrical supply is low voltage but high amperage and may be either alternating or direct .
电弧焊在一种或另一种形式是应用最广泛的焊接形式。电力供应是低电压，但是大电流，并且可以是交流或直流。
2.the earliest forms of arc welding used carbon electrodes.but nowadays the arc is struck between a metal electrode and workpiece .the electrode may either be of tungsten or be a consumable metal electrode that melts ,acting as a source of filler metal .
电弧焊接的最早的形式使用碳电极，但现在的电弧触发一个金属电极与工件之间，电极可以是钨或可熔化，作为填充金属供源的消耗性金属电极。
3.an alternating-current arc is broken and re-established at each half cycle and this leads to arc instability although the use of arc-established agents in the flux coating of electrode wires can overcome this problem .
交流电弧被打破并且重新建立在每个半周期，这导致电弧不稳定虽然在电极布线焊剂涂层使用电弧建立剂可以克服这个问题。
4.uncoated welding rods can be used for arc wilding .but it is more usual to use flux-coated electrodes .when steels are welded using uncoated electrodes,oxides and nitrides can form and remain in the weld with a consequent loss of toughness .
未涂覆的焊条可以用于电弧焊。但更通常使用的焊剂涂覆的电极。当钢在使用未涂覆的电极焊接，氧化物和氮化物能够形成并保持在焊缝韧性因此而丧失。
5.flux-coated electrodes are widely used .the composition of the coatings is complex and a variety of different coatings are used to cater for different types of welding application .
焊剂涂覆的电极被广泛使用。涂层的组成是复杂和各种不同的涂料是用于配合不同类型的焊接应用。
6.in this case the electron flow is from electrode to work-piece .A concentrated arc issues from the electrode tip and heating of the work-piece is largely confined to the very small ares beneath the electrode .
在这种情况下电子流动是从电极到工件，从电极头和工件的加热浓缩的弧的问题在很大程度上仅限于电极下方的非常小顷。
第十章：钢
1.In simple terms, a plain carbon steel may be said to be an alloy of iron and carbon containing less than 1.7% carbon. In practice, however, these steels rarely contain more than 1.4% carbon and other elements are also present, either as deliberate additions (e. g. manganese) or as impurities (e. g. sulphur and phosphorus).
简单来说，普通碳素钢也被称为含碳量少于1.7%的合金钢。然而事实上，这些钢材中很少有含碳量多于1.4%，同时也含有其它元素，例如一些额外添加物（如锰）或者杂质（如硫和磷）。
2.In the manufacture of this material, complete deoxidation is not carried out and it is made as rimming steel. It is produced as hot and cold worded sheet, strip, rod, wire and tube, and is available in the hot-worked or process annealed condition.
在材料的生产加工中，不能实现脱氧还原反应的钢被称为沸腾钢。它被用来生产热处理或冷处理的薄片、带、棒、电线、和管，并且它适用热轧和退火的情况下。
3.The strength and hardness of these steel is low, but a hard surface can be obtained by carbursing in order to combine a wear-resistant surface with tough core properties.
钢的强度和硬度低，可以通过渗碳的方法获得表面硬化以达到表面耐寒内部韧性较好的特性。
4.As the carbon content is raised above 0.2%, the strength increases into the range required for constructional purposes, but the ductility decreases. The fabrication qualities (working and welding characteristics) of this material are very good.
一旦钢中含碳量上升超过0.2%，结构上的强度会发生巨大变化，但是其延展性会下降。材料的制造质量（承载和焊接特性）非常好。
5.Medium carbon steels are often quenched-hardened and fully tempered to give good strength with maximum toughness, which are the properties required of components such as shafts, gears and connecting rods.
中碳钢常被淬火硬化和高温回火处理以便给予良好的温度和最大的韧性，这些是轴、齿轮和连杆所要求的能力特性。
6.High carbon steels are quench hardened and lightly tempered to give high hardness with only limited toughness. Material in this classification is mainly used for making fairly small, relatively inexpensive cutting tools so that the group as a whole is known as carbon tool steel. 高碳钢常被淬火硬化和低温回火处理以便给予高硬度和一定韧性。此类材料主要被用于生产相当小、可靠地、廉价的切削工具，者这就是碳素工具钢。
第十一章：金属热加工
1.The principal kinds of heat-treatment used in practice .which differently affect the structure and properties ,and which are assigned to meet the requirements made to the semifabricated materials (castings forgings ,rolled stock ,etc.)and finished articles :are (1)annealing (2)normalizing (3)hardening and (4)tempering .
所用的主要种类热处理的做法，以不同方式影响结构和性能，并分配给满足于半加工材料制成的要求（铸件锻件，轧材等）和必要的类型：是（1）退火（2）正火，（3）淬火和（4）回火。
2.Normalizing raises the strength and hardness of medium and high-carbon steels by 10 to 15 percent as compared to annealed steel.
正火引起较退火的钢的强度和中等和高碳钢硬度由10至15％。
3.Martensite is very hard and brittle ,having a much highertensile strength than the steel with a pearlite microstructure .
马氏体是非常硬且脆的，具有高得多的抗张强度比钢具有珠光体组织。
4.Tempering,or drawing ,is a process of reheating a steel part that has been previously hardened to transform hard martensite into softer structure .the higher the tempering temperature used ,the softer and tougher the piece becomes .
回火，是再加热先前已硬化改造硬马氏体成较软的结构的钢部件的工艺。回火温度中使用的较高，较软及更韧的片而成。
5.For low carbon steels ,normalizing enables a better surface finish to be obtained in machining and raise the production capacity .
对于低碳钢，正火使得能够在加工得到更好的表面光洁度，并提高生产能力。
6.In commercial tempering the temperature range of 250-425℃ is usually avoided because of an unexplained embrittlement ,or loss of ductility ,that often occurs with steels tempered in this range .
在商业回火250-425℃的温度范围通常是可以避免的，因为一种原因不明的脆化，或塑性的损失，经常发生回火钢在此范围内。
15课
The main components of a lathe are the headstock and tailstock at opposite ends of a bed, and a tool-post between them which holds the cutting tool.
车床的一个主要组成部分是车头和在床对面末的尾架，和在它们之间的刀架T
he size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum distance between centers. Smaller engine lathes——with swings usually not over 330 mm(13 inches)——also are available in type, designed for the bed to be mounted on a bench or cabinet.
该车床的大小被指定两个维度。第一个被称为摆动。这是工作的最大直径可旋转车床。第二个层面是大小中心之间的最大距离。
Although engine lathe are versatile and useful, because of the time required for changing and setting tools and for making measurements on the workspace, they are not suitable for quantity production.
虽然车床是多功能和有用的，因为改变和设置工具和工件上进行测量所需的时间，他们不合适的大量生产。
However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made.
不过，运营商的大部分时间是消耗在简单，重复的调整和看芯片正在取得进展。Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely usedinmanufacturing.
因此，要减少或消除所需要的劳动技能，转塔车床，螺丝机量，半自动及自动车床等类型
已经高度发达，被广泛用于生产中。
Lesson 1 力学的基本概念 1、词汇： statics [st?tiks] 静力学；dynamics动力学；constraint约束；magnetic [m?ɡ＇netik]有磁性的；external [eks＇t?:nl] 外面的, 外部的；meshing啮合；follower从动件；magnitude [＇m?ɡnitju:d] 大小；intensity强度，应力；non-coincident [k?u＇insid?nt]不重合；parallel [＇p?r?lel]平行；intuitive 直观的；substance物质；proportional [pr?＇p?:??n?l]比例的；resist抵抗，对抗；celestial [si＇lestj?l]天空的；product乘积；particle质点；elastic [i＇l?stik]弹性；deformed变形的；strain拉力；uniform全都相同的；velocity[vi＇l?siti]速度；scalar[＇skeil?]标量；vector[＇vekt?]矢量；displacement代替；momentum [m?u＇ment?m]动量； 2、词组 make up of由……组成；if not要不，不然；even through即使，纵然； Lesson 2 力和力的作用效果 1、词汇： machine 机器；mechanism机构；movable活动的；given 规定的，给定的，已知的；perform执行；application 施用；produce引起，导致；stress压力；applied施加的；individual单独的；muscular [＇m?skjul?]]力臂；gravity[ɡr?vti]重力；stretch伸展，拉紧，延伸；tensile[tensail]拉力；tension张力，拉力；squeeze挤；compressive 有压力的，压缩的；torsional扭转的；torque转矩；twist扭，转动；molecule [m likju:l]分子的；slide滑动; 滑行；slip滑，溜；one another 互相；shear剪切；independently独立地，自立地；beam梁；compress压；revolve (使)旋转；exert [iɡ＇z?:t]用力，尽力，运用，发挥，施加；principle原则, 原理，准则，规范；spin使…旋转；screw螺丝钉；thread螺纹； 2、词组 a number of 许多；deal with 涉及，处理；result from由什么引起；prevent from阻止，防止；tends to 朝某个方向；in combination结合；fly apart飞散； 3、译文： 任何机器或机构的研究表明每一种机构都是由许多可动的零件组成。这些零件从规定的运动转变到期望的运动。另一方面，这些机器完成工作。当由施力引起的运动时，机器就开始工作了。所以，力和机器的研究涉及在一个物体上的力和力的作用效果。 力是推力或者拉力。力的作用效果要么是改变物体的形状或者运动，要么阻止其他的力发生改变。每一种
数学专业英语课后答案
2.1数学、方程与比例 词组翻译 1.数学分支branches of mathematics，算数arithmetics，几何学geometry，代数学algebra，三角学trigonometry，高等数学higher mathematics，初等数学elementary mathematics，高等代数higher algebra，数学分析mathematical analysis，函数论function theory，微分方程differential equation 2.命题proposition，公理axiom，公设postulate，定义definition，定理theorem，引理lemma，推论deduction 3.形form，数number，数字numeral，数值numerical value，图形figure，公式formula，符号notation(symbol)，记法/记号sign，图表chart 4.概念conception，相等equality，成立/真true，不成立/不真untrue，等式equation，恒等式identity，条件等式equation of condition，项/术语term，集set，函数function，常数constant，方程equation，线性方程linear equation，二次方程quadratic equation 5.运算operation，加法addition，减法subtraction，乘法multiplication，除法division，证明proof，推理deduction，逻辑推理logical deduction 6.测量土地to measure land，推导定理to deduce theorems，指定的运算indicated operation，获得结论to obtain the conclusions，占据中心地位to occupy the centric place 汉译英 （1）数学来源于人类的社会实践，包括工农业的劳动，商业、军事和科学技术研究等活动。 Mathematics comes from man’s social practice, for example, industrial and agricultural production, commercial activities, military operations and scientific and technological researches. （2）如果没有运用数学，任何一个科学技术分支都不可能正常地发展。 No modern scientific and technological branches could be regularly developed without the application of mathematics. （3）符号在数学中起着非常重要的作用，它常用于表示概念和命题。 Notations are a special and powerful tool of mathematics and are used to express conceptions and propositions very often. （4）17 世纪之前，人们局限于初等数学，即几何、三角和代数，那时只考虑常数。Before 17th century, man confined himself to the elementary mathematics, i. e. , geometry, trigonometry and algebra, in which only the constants were considered. （5）方程与算数的等式不同在于它含有可以参加运算的未知量。 Equation is different from arithmetic identity in that it contains unknown quantity which can join operations. （6）方程又称为条件等式，因为其中的未知量通常只允许取某些特定的值。Equipment is called an equation of condition in that it is true only for certain values of unknown quantities in it. （7）方程很有用，可以用它来解决许多实际应用问题。
01.THE ELEMENTS AND THE PERIODIC TABLE 01元素和元素周期 表。 The number of protons in the nucleus of an atom is referred to as the atomic number, or proton number, Z. The number of electrons in an electrically neutral atom is also equal to the atomic number, Z. The total mass of an atom is determined very nearly by the total number of protons and neutrons in its nucleus. This total is called the mass number, A. The number of neutrons in an atom, the neutron number, is given by the quantity A-Z. 原子核中的质子数的原子称为原子序数，或质子数，卓电子数的电中性的原子也等于原子序数Z，总质量的原子是非常接近的总数量的质子和中子在原子核。这被称为质量数，这个数的原子中的中子，中子数，给出了所有的数量 The term element refers to, a pure substance with atoms all of a single kind. To the chemist the "kind" of atom is specified by its atomic number, since this is the property that determines its chemical behavior. At present all the atoms from Z = 1 to Z = 107 are known; there are 107 chemical elements. Each chemical element has been given a name and a distinctive symbol. For most elements the symbol is simply the abbreviated form of
1.机械设计过程 机械设计的最终目标是生产一种满足客户需求的有用产品，而且这种产品安全，高效，可靠，经济，实用。当回答这个问题时，广泛地思考，我将要设计的产品或系统的客户是谁？ 在产品设计之前，了解所有客户的期望和期望是至关重要的。营销专业人员经常被用来管理客户期望的定义，但是设计师可能会把他们作为产品开发团队的一部分。 许多方法被用来确定客户想要什么。一种被称为质量功能部署或QFD的流行方法寻求（1）识别客户期望的所有特征和性能因素，以及（2）评估这些因素的相对重要性。QFD过程的结果是产品的一组详细功能和设计要求。 考虑设计过程如何配合为客户提供令人满意的产品所必须发生的所有功能以及在产品的整个生命周期中为产品提供服务也很重要。事实上，重要的是考虑产品在使用寿命后如何处置。影响产品的所有这些功能的总和有时被称为产品实现过程或PRP。PRP中包含的一些因素如下： ?营销功能来评估客户的要求 ?研究确定可在产品中合理使用的可用技术 ?可以包含在产品中的材料和组件的可用性 ?产品设计和开发 ?性能测试 ?设计文件 ?供应商关系和采购职能 ?考虑全球材料采购和全球营销 参加工作的技能 ?物理工厂和设施可用
?制造系统的能力 生产计划和生产系统的控制 ?生产支持系统和人员 ?质量体系要求 ?销售操作和时间表 ?成本目标和其他竞争性问题 ?客户服务要求 ?产品在生产，操作和处置过程中的环境问题 ?法律要求 ?金融资本的可用性 你可以添加到这个列表吗？您应该能够看到，产品的设计只是综合过程的一部分。在本文中，我们将更加注意设计过程本身，但必须始终考虑设计的可生产性。产品设计和制造过程设计的同时考虑通常被称为并行工程。 2.机械设计所需的技能 产品工程师和机械设计师在日常工作中使用广泛的技能和知识。这些技能和知识包含在以下内容中： ?素描，技术制图和计算机辅助设计 ?材料的性质？材料加工*和制造过程 ?化学的应用，如腐蚀防护，电镀和喷漆 静力学动力学材料的强度，运动学和机制 流体力学，热力学和传热 ?流体动力，电气现象的基本原理和工业控制
2.1 数学、方程与比例 （1）数学来源于人类的社会实践，包括工农业的劳动，商业、军事和科学技术研究等活动。 Mathematics comes from man’s social practice, for example, industrial and agricultural production, commercial activities, military operations and scientific and technological researches. （2）如果没有运用数学，任何一个科学技术分支都不可能正常地发展。 No modern scientific and technological branches could be regularly developed without the application of mathematics. （3）符号在数学中起着非常重要的作用，它常用于表示概念和命题。Notations are a special and powerful tool of mathematics and are used to express conceptions and propositions very often. （4）17 世纪之前，人们局限于初等数学，即几何、三角和代数，那时只考虑常数。 Before 17th century, man confined himself to the elementary mathematics, i. e. , geometry, trigonometry and algebra, in which only the constants were considered. （5）方程与算数的等式不同在于它含有可以参加运算的未知量。 Equation is different from arithmetic identity in that it contains unknown quantity which can join operations. （6）方程又称为条件等式，因为其中的未知量通常只允许取某些特定的值。Equipment is called an equation of condition in that it is true only for certain values of unknown quantities in it. （7）方程很有用，可以用它来解决许多实际应用问题。 Equations are of very great use. We can use equations in many mathematical problems. （8）解方程时要进行一系列移项和同解变形，最后求出它的根，即未知量的值。To solve the equation means to move and change the terms about without making the equation untrue, until the root of the equation is obtained, which is the value of unknown term. 2.2 几何与三角 （1）许多专家都认为数学是学习其他科学技术的必备基础和先决条件。 Many experts recognize that mathematics is the necessary foundation and prerequisite of studying other science technology. （2）西方国家的专家认为几何起源于巴比伦和埃及人的土地测量技术，其实中国古代的数学家对几何做了许多出色的研究。 The western experts think that geometry had its origin in the measurements by the Babylonians and Egyptians of their lands. Infect, the ancient Chinese mathematicians made much remarkable study for geometry. （3）几何的学习使学生在思考问题时更周密和审慎，他们将不会盲目接受任何结论。 In studying geometry, the student is taught to think clearly and critically and he is led away from the practice of blind acceptance of any conclusions. （4）数学培养学生的分析问题的能力，使他们能应用毅力、创造性和逻辑推理来解决问题。
Unit 1 Chemical Industry 化学工业 1.Origins of the Chemical Industry Although the use of chemicals dates back to the ancient civilizations, the evolution of what we know as the modern chemical industry started much more recently. It may be considered to have begun during the Industrial Revolution, about 1800, and developed to provide chemicals roe use by other industries. Examples are alkali for soapmaking, bleaching powder for cotton, and silica and sodium carbonate for glassmaking. It will be noted that these are all inorganic chemicals. The organic chemicals industry started in the 1860s with the exploitation of William Henry Perkin‘s discovery if the first synthetic dyestuff—mauve. At the start of the twentieth century the emphasis on research on the applied aspects of chemistry in Germany had paid off handsomely, and by 1914 had resulted in the German chemical industry having 75% of the world market in chemicals. This was based on the discovery of new dyestuffs plus the development of both the contact process for sulphuric acid and the Haber process for ammonia. The later required a major technological breakthrough that of being able to carry out chemical reactions under conditions of very high pressure for the first time. The experience gained with this was to stand Germany in good stead, particularly with the rapidly increased demand for nitrogen-based compounds (ammonium salts for fertilizers and nitric acid for explosives manufacture) with the outbreak of world warⅠin 1914. This initiated profound changes which continued during the inter-war years (1918-1939). 1．化学工业的起源 尽管化学品的使用可以追溯到古代文明时代，我们所谓的现代化学工业的发展却是非常近代（才开始的）。可以认为它起源于工业革命其间，大约在1800年，并发展成为为其它工业部门提供化学原料的产业。比如制肥皂所用的碱，棉布生产所用的漂白粉，玻璃制造业所用的硅及Na2CO3. 我们会注意到所有这些都是无机物。有机化学工业的开始是在十九世纪六十年代以William Henry Perkin 发现第一种合成染料—苯胺紫并加以开发利用为标志的。20世纪初，德国花费大量资金用于实用化学方面的重点研究，到1914年，德国的化学工业在世界化学产品市场上占有75%的份额。这要归因于新染料的发现以及硫酸的接触法生产和氨的哈伯生产工艺的发展。而后者需要较大的技术突破使得化学反应第一次可以在非常高的压力条件下进行。这方面所取得的成绩对德国很有帮助。特别是由于1914年第一次世界大仗的爆发，对以氮为基础的化合物的需求飞速增长。这种深刻的改变一直持续到战后（1918-1939）。 date bake to/from: 回溯到 dated: 过时的，陈旧的 stand sb. in good stead: 对。。。很有帮助
“数学专业英语一次函数专题”教学设计 1. 教学内容及解析 教学内容：与直角坐标系及一次函数相关的英语文献资料 内容解析：本节内容应从两个方面去考虑. 一方面，从数学知识的角度，本节所涉及的是从平面直角坐标系到一次函数的数学知识，都是学生学过的基础知识及其应用，是对于这些知识的拉练式复习，并作为后面用英语叙述解答相关问题知识基础；另一方面，从语言的角度，学生会接触到大量没有接触过，但他们却很熟悉的英语词汇及短语，主动学习的学生可以在老师的指导下快速理解其含义并加入到自己的知识体系中，但需要花时间巩固，是需要读、写、说来巩固的内容. 这也正是本节的重点和难点所在. 2. 教学目标及解析 教学目标：①能根据已有的数学知识和给出的单词对照表，将给出的相关数学定理及结论的英语版本翻译为中文；②能理解并解答用英语表述的相关数学问题；③能将解决数学问题的过程用英语进行书面表述；④初步了解用英语表达与直角坐标系及一次函数相关数学理论的范式. 目标解析：学生掌握基本词汇，并能阅读与本节内容相关的英语文献，是学习和使用数学专业英语的最基本要求，学生需要在学习的过程中逐渐由接受，即阅读或聆听，逐渐向输出，即书面和口头表达的方向发展. 为达到此目标，学生需要在课前独立完成对于本节需要的单词的学习，并阅读一系列简短的相关数学文献，并在这个过程中初步体会数学专业英语的表达范式；在课堂上，在教师的指导下对自己的认知进一步补充，并进行一定量的练习，暴露自己的问题，在教师的帮助下修正问题，完善认知. 3. 教学问题诊断分析 学生在进行语言表达时，往往受到母语的限制，对于非母语的表达方式的接受能力一时难以习惯，而数学对于表达能力则有更高的要求，要求叙述简洁、逻辑清晰，因此本教学设计强调学生在有相当阅读量的积累后，通过自主练习，逐渐感受用英语表达数学理论的基本范式. 教师在教学过程中的主要任务在于为学生提供合适的学习资料，在学生学习的过程中给予提示与指导，及时指出学生的问题并予以纠正. 对于语言的学习，阅读量的积累是至关重要的，教师在课堂上的讲解、学生在课堂上的练习，都只是学习的一部分环节，如果需要帮助学生正确掌握表达数学理论的范式，尽量不留死角，就必须保证课前预习和课后复习的有效性，预习复习材料的充足性，这对教师的教学资料的积累和学生自主学习能力，都是一个挑战. 4. 教学支持条件分析 学情条件：初二8班是实验班，学生有较强的学习热情和好奇心，也知道课前预习、课上参与学习活动、课后复习的重要性，在曾经的数学课程教学中，也有一定的课前预习，课堂讨论的传统，对于本教学设计的各个环节，是可以理解教师的用意，并遵循教师的指导进行学习活动. 在知识层面上，学生已经系统学习过一次函数相关的知识，课程中提供的学习资料都是学生熟悉的数学知识；学生在英语学习上，已经有多年的积累，对于英语语法的学
陶瓷ceramics 合成纤维synthetic fibre 电化学腐蚀electrochemical corrosion 车架automotive chassis 悬架suspension 转向器redirector 变速器speed changer 板料冲压sheet metal parts 孔加工spot facing machining 车间workshop 工程技术人员engineer 气动夹紧pneuma lock 数学模型mathematical model 画法几何descriptive geometry 机械制图Mechanical drawing 投影projection 视图view 剖视图profile chart 标准件standard component 零件图part drawing 装配图assembly drawing 尺寸标注size marking 技术要求technical requirements 刚度rigidity 内力internal force 位移displacement 截面section 疲劳极限fatigue limit 断裂fracture 塑性变形plastic distortion 脆性材料brittleness material 刚度准则rigidity criterion 垫圈washer 垫片spacer 直齿圆柱齿轮straight toothed spur gear 斜齿圆柱齿轮helical-spur gear 直齿锥齿轮straight bevel gear 运动简图kinematic sketch 齿轮齿条pinion and rack 蜗杆蜗轮worm and worm gear 虚约束passive constraint 曲柄crank 摇杆racker 凸轮cams
Unit 2 Research and Development 研究和开发 Research and development, or R&D as it is commonly referred to, is an activity which is carried out by all sectors of manufacturing industry but its extent varies considerably, as we will see shortly. Let us first understand, or at least get a feel for, what the terms mean. Although the distinction between research and development is not always clear-cut, and there is often considerable overlap, we will attempt to separate them. In simple terms research can be thought of as the activity which produces new ideas and knowledge whereas development is putting those ideas into practice as new process and products. To illustrate this with an example, predicting the structure of a new molecule which would have a specific biological activity and synthesizing it could be seen as research whereas testing it and developing it to the point where it could be marketed as a new drug could be described as the development part. 研究和开发，或通常所称R&D是制造业各个部门都要进行的一项活动。我们马上可以看到，它的内容变化很大。我们首先了解或先感觉一下这个词的含义。尽管研究和开发的定义总是分得不很清楚，而且有许多重叠的部分，我们还是要试着把它们区分开来。简单说来，研究是产生新思想和新知识的活动，而开发则是把这些思想贯彻到实践中得到新工艺和新产品的行为。可以用一个例子来描述这一点，预测一个有特殊生物活性的分子结构并合成它可以看成是研究而测试它并把它发展到可以作为一种新药推向市场这一阶段则看作开发部分。 1.Fundamental Research and Applied Research In industry the primary reason for carting out R&D is economic and is to strengthen and improve the company?s position and profitability. The purpose of R&D is to generate and provide information and knowledge to reduce uncertainty, solve problems and to provide better data on which management can base decisions. Specific projects cover a wide range of activities and time scales, from a few months to 20 years. 1．基础研究和应用研究 在工业上进行研究和开发最主要的原因是经济利益方面，是为了加强公司的地位，提高公司的利润。R&D的目的是做出并提供信息和知识以减低不确定性，解决问题，以及向管理层提供更好的数据以便他们能据此做出决定。特别的项目涵盖很大的活动范围和时间范围，从几个月到20年。 We can pick out a number of areas of R&D activity in the following paragraphs but if we were to start with those which were to spring to the mind of the academic, rather than the industrial, chemist then these would be basic, fundamental (background) or exploratory research and the synthesis of new compounds. This is also labeled “blue skies” research. 我们可以在后面的段落里举出大量的R&D活动。但是如果我们举出的点子来源于研究院而不是工业化学家的头脑，这就是基础的或探索性的研究 Fundamental research is typically associated with university research. It may be carried out for its own intrinsic interest and it will add to the total knowledge base but no immediate applications of it in the “real world” well be apparent. Note that it will provide a valuable
1.我们可以把钢再次加热到临界温度以下的某一温度，然后在慢慢让其冷却。We can heat the steel again to a temperature below the critical temperature, then cool it slowly. 2.无论任何简单的机床，都是由单一元件即通称为机械零件或部件组成的。However simple, any machine is a combination of individual components generally referred to as machine elements or parts. 3.这些金属不都是好的导体。 All these metals are not good conductors. 4. 在做带电实验的时候，再怎么小心都不为过。 You can't be too careful in performing an experiment. 5.利用发电机可以把机械能转变成电能。 The mechanical energy can be changed back into electrical energy by means of a generator or dynamo. 6.假定电源输入的电压保持不变。 Assume that the voltage input of the power supply remains the same. 7.化石燃料是发电过程中最为频繁使用的能源。 Fossil fuels are most frequently used source daring the power generation process. 8单个机械零件的可靠性成为评估整台机器使用寿命的基本因素。 The individual reliability of machine elements becomes the basis for estimating the overall life 9.说我们生活在一个电子时代，这一点都不夸张。 It's no exaggeration to say that we live in an electronic age. 10.发动机的转速不应超过最大允许值。 Engine revolution should not exceed the maximum permissible. 11.如能从大型核电站获得成本极低的电力，电解氢的竞争能力就会增强。（Electrolytic hydrogen）。 If extremely low-cost power were ever to become available from large nuclear power plants, electrolytic hydrogen would become competitive. 12.电子技术提供了一种新的显示时间的方法。 A new way of displaying time has been given by electronics. 13.远距离输电需要高压，安全用电需要低压。 High voltage is necessary for long transmission line while low voltage for safe use. 14.铝的电阻大约是同等尺寸的铜的1.5倍。 The resistance of aluminum is approximately half again as great as that of copper for the same dimensions = size 15.In fact,it is impossible for no force to be exerted on a body,since in this world everything is subject to the for ce of gravity. 事实上，物体不受外力作用是不可能的，因为在这个世界上任何物体都要受到重力的作用。 16.In a thermal power plant,all the chemical energy is not
2.1数学、方程与比例 词组翻译 1.数学分支branches of mathematics，算数arithmetics，几何学geometry，代数学algebra，三角学trigonometry，高等数学higher mathematics，初等数学elementary mathematics，高等代数higher algebra，数学分析mathematical analysis，函数论function theory，微分方程differential equation 2.命题proposition，公理axiom，公设postulate，定义definition，定理theorem，引理lemma，推论deduction 3.形form，数number，数字numeral，数值numerical value，图形figure，公式formula，符号notation(symbol)，记法/记号sign，图表chart 4.概念conception，相等equality，成立/真true，不成立/不真untrue，等式equation，恒等式identity，条件等式equation of condition，项/术语term，集set，函数function，常数constant，方程equation，线性方程linear equation，二次方程quadratic equation 5.运算operation，加法addition，减法subtraction，乘法multiplication，除法division，证明proof，推理deduction，逻辑推理logical deduction 6.测量土地to measure land，推导定理to deduce theorems，指定的运算indicated operation，获得结论to obtain the conclusions，占据中心地位to occupy the centric place 汉译英 （1）数学来源于人类的社会实践，包括工农业的劳动，商业、军事和科学技术研究等活动。 Mathematics comes from man’s social practice, for example, industrial and agricultural production, commercial activities, military operations and scientific and technological researches. （2）如果没有运用数学，任何一个科学技术分支都不可能正常地发展。 No modern scientific and technological branches could be regularly developed without the application of mathematics. （3）符号在数学中起着非常重要的作用，它常用于表示概念和命题。 Notations are a special and powerful tool of mathematics and are used to express conceptions and propositions very often. （4）17 世纪之前，人们局限于初等数学，即几何、三角和代数，那时只考虑常数。 Before 17th century, man confined himself to the elementary mathematics, i. e. , geometry, trigonometry and algebra, in which only the constants were considered. （5）方程与算数的等式不同在于它含有可以参加运算的未知量。 Equation is different from arithmetic identity in that it contains unknown quantity which can join operations. （6）方程又称为条件等式，因为其中的未知量通常只允许取某些特定的值。Equipment is called an equation of condition in that it is true only for certain values of unknown quantities in it. （7）方程很有用，可以用它来解决许多实际应用问题。
2、应力和应变 在任何工程结构中独立的部件或构件将承受来自于部件的使用状况或工作的外部环境的外力作用。如果组件就处于平衡状态,由此而来的各种外力将会为零,但尽管如此,它们共同作用部件的载荷易于使部件变形同时在材料里面产生相应的内力。 有很多不同负载可以应用于构件的方式。负荷根据相应时间的不同可分为: (a)静态负荷是一种在相对较短的时间内逐步达到平衡的应用载荷。 (b)持续负载是一种在很长一段时间为一个常数的载荷, 例如结构的重量。这种类型的载荷以相同的方式作为一个静态负荷; 然而,对一些材料与温度和压力的条件下,短时间的载荷和长时间的载荷抵抗失效的能力可能是不同的。 (c)冲击载荷是一种快速载荷(一种能量载荷)。振动通常导致一个冲击载荷, 一般平衡是不能建立的直到通过自然的阻尼力的作用使振动停止的时候。 (d)重复载荷是一种被应用和去除千万次的载荷。 (e)疲劳载荷或交变载荷是一种大小和设计随时间不断变化的载荷。 上面已经提到，作用于物体的外力与在材料里面产生的相应内力平衡。因此,如果一个杆受到一个均匀的拉伸和压缩，也就是说, 一个力,均匀分布于一截面,那么产生的内力也均匀分布并且可以说杆是受到一个均匀的正常应力,应力被定义为 应力==负载 P /压力 A, 因此根据载荷的性质应力是可以压缩或拉伸的,并被度量为牛顿每平方米或它的倍数。 如果一个杆受到轴向载荷，即是应力，那么杆的长度会改变。如果杆的初始长度L和改变量△L已知，产生的应力定义如下: 应力==改变长△L /初始长 L 因此应力是一个测量材料变形和无量纲的物理量 ,即它没有单位;它只是两个相同单位的物理量的比值。 一般来说,在实践中,在荷载作用下材料的延伸是非常小的, 测量的应力以*10-6的形式是方便的, 即微应变, 使用的符号也相应成为ue。 从某种意义上说，拉伸应力与应变被认为是正的。压缩应力与应变被认为是负的。因此负应力使长度减小。 当负载移除时，如果材料回复到初始的，无负载时的尺寸时，我们就说它是具有弹性的。一特定形式的适用于大范围的工程材料至少工程材料受载荷的大部分的弹性, 产生正比于负载的变形。由于载荷正比于载荷所产生的压力并且变形正比于应变, 这也说明,当材料是弹性的时候, 应力与应变成正比。因此胡克定律陈述, 应力正比于应变。 这定律服从于大部分铁合金在特定的范围内, 甚至以其合理的准确性可以假定适用于其他工程材料比如混凝土，木材，非铁合金。 当一个材料是弹性的时候，当载荷消除之后，任何负载所产生的变形可以完全恢复,没有永久的变形。