As against this well-defined behavior of a simple chemical compound, a polymer like polyethylene does not melt sharply at one particular temperature into clean liquid. 与这类简单化合物明确的行为相比，像聚乙烯这样的聚合物不能在某一特定的温度快速地熔融成纯净的液体。
Also, we can add a very large quantity of the polymer to the same quantity of water without the saturation point ever being reached. 同样地，我们可以将大量的聚合物加入到同样量的水中，不存在饱和点。
While linear polymers are important, they are not the only type of molecules possible. 线状聚合物是很重要的,他们不是唯一可能类型的分子。
Substituent groups such as methyl or phenyl groups on the repeat units are not considered branches. Branching is generally introduced into a molecule by intentionally adding some monomer with the capability of serving as a branch. Let us consider the formation of a polyester. The presence of difunctional acids and difunctional alcohols allows the polymer chain to grow. These difunctional molecules are incorporated into the chain with ester linkages at both ends of each. Trifunctional acids or alcohols, on the other hand, produce a linear molecule by reacting two of their functional groups. If the third reacts and the resulting chain continues to grow, a branch has been introduced into the original chain. Adventitious branching sometimes occurs as a result of an atom being abstracted from the original linear molecule, with chain growth occurring from the resulting active site. Molecules with this kind of accidental branching are generally still called linear, although the presence of significant branching has profound effects on some properties of the polymer, most notably the tendency to undergo crystallization.
The polymerization is a chain reaction in two ways: because of the reaction kinetic and because as a reaction product one obtains a chain molecule. 聚合反应是链式反应的原因有两种：因为反应动力学和因为作为反应产物它是一种链式分子。
Thus, molecular weight increases slowly even at high levels of monomer conversion, and it will continue to increase until the viscosity build-up makes it mechanically too difficult to remove water of esterification or for reactive end groups to find each other. 因此，聚合反应将以逐步的方式继续进行，其每一步酯化反应的反应速率和反应机理均与初始单体的酯化作用相同。因此，分子量缓慢增加直至高水平的单体转化率，而且分子量将继续增加直到粘度的增加使其难以除去酯化反应的水或难以找到相互反应的端基。
If some monofunctional impurity is present, its reaction will limit the molecular weight by rendering a chain end inactive. Similarly, high-purity monomers are necessary in the A-B type of polycondensation and it follows that high-yield reactions are the only practical ones for polymer formation, since side reactions will upset the stoichiometric balance. 假如存在一些但官能团杂质，由于链的端基失活，反应将使分子量减少。同样，在A-B类的缩聚反应中高纯度的单体是必要的，而且可以归结高收率的反应仅是形成聚合物的实际反应，因为副反应会破坏当量平衡。
Chain termination takes place only through impurities, or through the addition of certain compounds such as water, alcohols, acids, amines, or oxygen, and in general through compounds which can react with polymerization ions under the formation of neutral compounds or inactive ionic species. 链终止反应仅仅通过杂质而发生，或者说通过和某些像水、醇、酸、胺或氧这样的化合物进行加成而发生，且一般来说（链终止反应）可通过这样的化合物来进行，这种化合物在中性聚合物或没有聚合活性的离子型聚合物生成的过程中可以和活性聚合
物离子进行反应。
Above that size, there is a rapid increase in the mechanical performance of polymers as their molecular weight increase; the effect levels off at still higher molecular weights. 以上尺寸,有迅速增长的力学性能,增加聚合物作为他们的分子量影响;从更高层次分子量。
The reason for the polydispersity of polymers lies in the statistical variations present in the polymerization processes. 原因在于分子量分布聚合物的统计变化出现在聚合过程。
Different average molecular weights are obtained because the properties being measured are biased differently toward the different sized polymer molecules in a polymer sample. 平均分子量不同性能得到被测因为有偏见对不同大小不同的聚合物分子在聚合物样品。
The purification effect of the extraction is in most cases rather slight because in many instances the impurity is held to the polymer by strong secondary valence forces. 萃取净化效果在很多情况下都不大,因为在许多情况下,杂质被聚合物由强大的二次价的力量。
Methanol is a sort of general precipitating agent in which most polymers, both the benzene-soluble ones and the water-soluble polymers, are insoluble. 甲醇是一种一般沉淀剂在聚合物两大部分,benzene-soluble孩子、水溶性高分子化合物,是无法解决的。
Initiators and other additives, such as emulsifying agents and protective colloids,are also selected wherever possible in such a way that they can remain in the polymer without causing problems. 发起人和其它添加剂,如乳化剂和保护胶体特性,也尽可能选择这样一种方式,他们保持在聚合物而不引起的问题。
In solution, a polymer molecule is a randomly coiling mass most of whose conformations occupy many times the volume of its segments alone. 在溶液中,聚合物分子质量的随机盘绕占据最多次采样体积的部分独自一人。
The folded-chain lamella theory arose in the late 1950's when polymer single crystals in the form of thin platelets termed lamella were grown from polymer solutions. folded-chain薄板理论的兴起于1950年代后期当聚合物单晶硅薄血小板的形式被称为薄板种植从聚合物溶液。
Amorphous polymers are usually considered to be a random tangle of molecules. It is, however, apparent that completely random packing cannot occur. This follows even from simple arguments based on the comparatively high density but there is no distinct structure as, for example, revealed by X-ray diffraction techniques. 非晶态聚合物通常被认为是一个随机纠缠不清的分子。不过,很明显的,不能完全随机的包装发生。这跟甚至从简单的论点基于密度较高,但没有明显的层次性,如经x -射线衍射技术显示。
Many polymers, including polyethylene terephthalate, also crystallize if they are cooled slowly from the melt. In this case we may say that they are crystalline but oriented. 许多聚合物动态,包括聚乙烯,如果他们被冷却结晶慢慢地从融化。在这个例子中,我们可以说他们是水晶但导向。
This fringed micelle model was called into question by the discovery of polymer single crystals grown from solution. 这须边花胶束模型也受到了怀疑的发现长出聚合物单晶硅的解决方案。
The influence of chain folding on the structure of bulk crystalline polymers is a matter of further controversy, although there is much evidence to support the existence of a lamellar morphology, and this is sometimes vital to the understanding of machanical properties. 链折叠的影响结构的散装水晶聚合物是一种进一步的争议,虽然现在有很多的证据支持层的存在形态,这有时是至关重要的,了解机械性质。
We are bound to conclude that the highly entangled topology of the chains which exists in
the melt must be substantially retained in the semicrystalline state. 我们肯定会得出这样的结论:高度纠缠拓扑链,它存在于熔体必须保留在实质上是半结晶状态。
Also,the polymer will be named according to its source whenever it is derived from a specific hypothetical monomer, or when it is derived from two or more components which are built randomly into the polymer. 同时,聚合物将被命名为根据其来源每当它是源自于一个特定的假设的单体,或者当它是源自于两个或多个部件建立随机进入聚合物。
Functional polymers are macromolecules to which chemically functional groups are attached; they have potential advantages of small molecules with the same functional groups. Their usefulness is related, both to the functional groups and to the nature of the polymer whose characteristic properties depend mainly on the extraordinarily large size of the molecules. 功能性聚合物是大分子化学官能团的相连的潜在优势,他们有小分子具有相同的功能组。它们的有用性,都是相关的功能组和自然的聚合物特性的主要依靠非常大的分子。
Each of the two approaches has its own advantages and disadvantages, and one approach may be preferred for the preparation of a particular functional polymer when the other would be totally impractical. the choice between the two ways to the synthesis of functionalized pilymers depends mainly on the required chemical and physical properties of the support for a specific application. Usually the requirements of the individual system must be thoroughly examined in order take full advantage of each of the preparative techniques. 这两种方法各有其自身的优势和劣势,最后一种方法可能要优先用于制备一个特定的功能高分子当其他的就完全不切实际。选择两种方式之间的功能化的合成pilymers主要取决于所需的化学和物理性能的支持为某一特定的应用。通常要求的个别的系统必须彻底地检查了为了充分利用每一个制备技术。
第一章汽车总论 1)Today’s average car contains more than 15,000 separate, individual parts that must work together. These parts can be grouped into four major categories: body, engine, chassis and electrical equipment 。P1 现在的车辆一般都由15000多个分散、独立且相互配合的零部件组成。这些零部件主要分为四类：车身、发动机、底盘和电气设备。 2)The engine acts as the power unit. The internal combustion engine is most common: this obtains its power by burning a liquid fuel inside the engine cylinder. There are two types of engine: gasoline (also called a spark-ignition engine) and diesel (also called a compression-ignition engine). Both engines are called heat engines; the burning fuel generates heat which causes the gas inside the cylinder to increase its pressure and supply power to rotate a shaft connected to the power train. P3 发动机作为动力设备，常见的类型是内燃机，其原理是通过发动机缸内的液体燃料燃烧而产生能量。发动机可分为两类：汽油机（点燃式）和柴油机（压燃式），都属于热力发动机。燃料燃烧产生热量使缸内气压上升，产生的能量驱动轴旋转，并传递给动力传动系。 第二章内燃机 1)Power train system: conveys the drive to the wheels 2)Steering system: controls the direction of movement 3)Suspension system: absorbs the road shocks 4)Braking system: slows down the vehicle P4 传动系把发动机输出的扭矩传递给驱动轮。传动系包括离合器（对应机械变速器）或液力变矩器（对应液力自动变速器）、变速器、驱动轴、主减速器、差速器和驱动桥。 5)Drum brakes have a drum attached to the wheel hub, and braking occurs by means of brake shoes expanding against the inside of the drum. With disc brakes, a disc attached to the wheel hub is clenched between two brake pads. P6 鼓式制动器的制动鼓和轮毂连接，制动蹄张开压紧制动鼓内侧从而产生制动。在盘式制动器上，连着轮毂的制动盘被紧紧夹在两个制动块之间。 1)Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn.The power stroke"uses up"the gas,so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture:this control of gas movement is the duty of the valves;An inlet valve allows the mixture to enter at the right time and an exhaust valve lets out the burnt gas after the gas has done its job . P10 活塞通过连杆和曲轴连接，使得气体带动曲轴旋转半圈。作功冲程耗尽了所有的气体，这样就必须采取相应的措施排出废气并且向气缸内充入新的可燃混合气：气体的运动由气门来控制。进气门使可燃混合气在恰当的时刻进入气缸，排气门使燃烧后的废气排出气缸。 2)The spark-ignition engine is an internal-combustion engine with externally supplied in ignition,which converts the energy cntained in the fuel to kinetic energy.The cycle of operations is spread over four piston strokes. To complete the full cycle it takes two revolutions of the crankshaft. P11 火花点火式发动机是由外部提供点火的内燃机，从而将含在燃料内的能量转化成动能。发动机的一个工作循环分布在活塞的四个行程中，一个完整的工作循环曲轴需要转动两圈。 3)The oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine. The oil drains off and runs down into the pan. Thus,there is constant circulation of oil between the pan and the working parts of the engine. P15
In the case of a resistor, the voltage-current relationship is given by Ohm’s law, which states that the voltage across the resistor is equal to the current through the resistor multiplied by the value of the resistance. 就电阻来说, 电压—电流的关系由欧姆定律决定。欧姆定律指出:电阻两端的 电压等于电阻上流过的电流乘以电阻值。 2]It may be that the inductor voltage rather than the current is the variable of interest in the circuit. 或许在电路中,人们感兴趣的变量是电感电压而不是电感电流。 Viewed in this light, it will be found that the analysis of three-phase circuits is little more difficult than that of single-phase circuits. 这样看来,三相电路的分析比单相电路的分析难不了多少。 At unity power factor, the power in a single-phase circuit is zero twice each cycle. 在功率因数为 1时,单相电路里的功率值每个周波有两次为零。 It should be noted that if the polarity of point Awith respect to N ( is assumed for the positive half-cycle, then when used in the same phasor diagram should be drawn opposite to, or 180? out of phase with, . 应该注意,如果把 A 点相对于 N 的极性(定为正半周,那么在用于同一相量图中时就应该画得同相反,即相位差为 180? One problem with electronic devices corresponding to the generalized amplifiers is that the gains, AU or AI, depend upon internal properties of the two-port system. 对应于像广义放大器这样的电子装置,一个问题就是增益 AU 或者 AI ,它们取决于两输入端系统的内部特性。
Unit1 发动机是汽车的心脏。汽车引擎的目的是将燃料转化为能量使汽车移动。最简单的方法是在发动机内部燃烧燃料。,因此,汽车发动机是一种内燃机,缸内燃烧燃料和燃烧的扩张力量转换成旋转力用来驱动汽车。 这里有多种类型的内燃机分为往复式和旋转式引擎;火花式点火或压缩式点火发动机;代用燃料发动机。 往复式发动机 最熟悉的组合是往复式,火花点火,四冲程汽油发动机,如图1-1a所示。现代汽车通常是由水冷活塞式内燃机,安装在汽车的前面,它的力量可以被传送到前轮，传到后轮,或所有车轮轮。一些汽车使用风冷式发动机,但这些通常效率不及液冷式。往复式发动机的另一个主要类型是柴油发动机(如图果1-1b所示),这是使用重型车辆，如卡车，公共汽车和少数家庭轿车。柴油和汽油发动机一般采用四冲程循环。 转子式发动机 转子式内发动机,也叫汪克尔发动机,由德国的Felix~Wankel在1954年开发的,可以提供一种低废气排放和大规模生产的可行性的发动机来替代往复式发动机机。在这种发动机中，三面转子在燃烧室的自由空间内旋转使其随着转子转动压缩和膨胀,见图1 - 2。燃料被吸入、压缩和被点火系统的点燃。膨胀的气体带动转子然后废气排出,如图1 - 3所示。旋转式引擎没有气门,活塞,连杆,往复部件,或曲轴。它提高了马力,基本上不会有震动,但它的油耗是高于传统活塞式发动机。 代用燃料汽车 内燃机消耗大量的石油,并造成严重的空气污染,因此,其他类型的燃料和非常规引擎被研究和发展。 可替代燃料汽车(AFV)是一种用常见的油箱的柔性燃料车辆，设计一种在不同混合的无铅汽油与乙醇或双燃料汽车运行，一种可使用替代燃料和传统燃料。一种高科技车辆(A TV)结合了新引擎,动力传动机构,传动系系统显著提高燃油经济性。最理想的替代燃料发动机燃烧燃料比传统汽油内燃机更为简洁,但仍然能够使用现有的加油站。 混合动力电动车 混合动力汽车或者混合电动汽车(HEV)(如图1 - 4所示),是由两个或两个以上的能源,其中之一是电力可以高英里每加仑，低排放。有两种类型的混合动力汽车,串联和并联式。在串联式电动汽车中,车辆动力所有动力来自同一个源头。例如,一个电动马达驱动的汽车电池和内燃机驱动发电机给电池充电。在并联混合动力,电力是通过这两个路径,电动机和内燃机驱动车辆。这一点,可能有助于电力汽车的电动发动机空转和加速度。内燃机巡航时,驱动传动系和给电池充电。 在当前生产混合动力车发动机和电动马达连接,同样的传播协助下电动引擎可以更小。
1.Our big old house was closely related with the joys and sorrows of four generations. 2.I planted these roses a long, long time ago before your mother was born. 3.Many sons left home to fight against the Fascist Nazi. 4.Take the first friendly greeting and always keep it deep in your heart. 1.He has prepared answers to the questions that he expects to confront during the interview. 2.His sad story touched us so deeply that we nearly cried. 3.The two of them are walking hand in hand along the river bank, chatting, laughing, and looking happy. 4.When he heart the exciting news, tears of joy welled up in his eyes. 5.People from Shanghai can understand Suzhou dialect with ease, for Shanghai dialect and Suzhou dialect have much in common. 6.Henry and his wife are looking into the possibility of buying a new house within three years. 7.He finally gave in to his daughter’s repeated requests to further her education abroad. 8.We locked all our valuables away before we went on holiday. 9.Although we have parted from eah other, I hope that we will remain good friends and that we will care for and help each other just as we did in the past. 10.At that critical moment, the army commander summoned all the officers to work out new strategies and tactics which would make it possible to conquer the enemy. Unit 2 1.A gracious manner adds the greatest splendour to your image. 2.I firmly believed the note my guest sent me didn’t take long to write. 3.The simple phrase “Excuse me.” made most of your irritation disappear. 4.Being on time is a virtue which belongs not only to the past but also to the present. 5.Y ou shouldn’t accept the other person’s presence without thinking of its importance. 6.Good manners produce the same feelings or actions in others. 1.I am sorry I am late; I was at a meeting and couldn’t get away. 2.At the concert whnever a singer finished singing a beautiful song, the audience would burst into loud cheers to show their appreciation. 3.As a stylish dresser, she is always wearing stylish clothes, but she seldom cares about what she eats or drinks. 4.The nurse tells me that the doctors have done wonders for your heart disease. 5.When awarding the prize, the chairman complimented the winner on his great contribution to mankind. 6.This problem has bothered the experts for many years. 7.The crowd of demonstrators melted away when the police arrived. 8.Since punctuality is a good habit, we should pay much attention to it and make great efforts to cultivate this good habit. 9.The old man cherishes that girl, as if she were his own daughter. 10.It is just a routine physical checkup, nothing to get worried about.
About car engine Of all automobile components,an automobile engie is the most complicated assembly with dominant effects on the function of an autombile.So, the engine is generally called the"heat"of an automobile. 在汽车的所有部件中，汽车发动机是最复杂的组件，其对整车性能有着决定性的作用。因而发动机往往被称作发动机的“心脏”。 There are actually various types of engines such as electric motors,stream engines,andinternal combustion engines.The internal combustion engines seem to have almost complete dominance of the automotive field.The internal combustion engine,as its name indicates,burns fuel within the cylinders and converts the expanding force of the combustion into rotary force used to propel the vehicle. 事实上，按动力来源分发动机有很多种，如电动机、蒸汽机、外燃机等。然而内燃机似乎在发动机领域有着绝对的统治地位。就像其字面意思一样，内燃机的染料在气缸内燃烧，通过将燃烧产生气体的膨胀力转换成转动力来驱动发动机前进。 Engine is the power source of the automobile.Power is produced by the linear motion of a piston in a cylinder.However,this linear motion must be changed into rotary motion to turn the wheels of cars or trucks.The puston attached to the top of a connecting rod by a pin,called a piston pin or wrist pin.The bottom of the connecting rod is attached to the crankshaft.The connecting rod transmits the up-and-down motion of the piston to the crankshaft,which changes it into rotary motion.The connecting rod is mounted on the crankshaft with large bearings called rod bearing.Similar bearings, called main bearings,are used to mount the crankshaft in the block. 发动机是整部车的动力来源。能量来自于活塞在气缸内的（往复）直线运动。然而这种（往复）直线运动必须要转换成旋转运动才能驱动车轮。活塞与连杆通过一个销来连接，这个销称为活塞销。连杆的下部连接于曲拐。连杆把活塞的上下往复运动传递给曲拐，从而将往复直线运动转变成旋转运动。连杆和曲拐的连接使用大的轴承，称之为连杆轴承，类似的轴承也用于将曲轴连接到机体，称之为主轴承。 They are generally two different types of cooling system:water-cooling system and air-cooling system.Water-cooling system is more common.The cooling medium, or coolant, in them is either water or some low-freezing liquid, called antifreeze.A water-cooling system consists of the engine water jacket, thermostat, water pump, radiator, radiator cap, fan, fan drive belt and neccessary hoses. 主要有两种类型的冷却系统：水冷和风冷。水冷系统更为普遍。系统所用冷却介质或是冷却液常委水或其他低凝固点液体，称为抗凝剂。一个完整的水冷系统包括机体水套，节温器，水泵，散热器，散热器罩，风扇，风扇驱动皮带和必需的水管。 A water-cooling system means that water is used as a cooling agent to circulate through the engine to absorb the heat and carry it to the radiator for disposal.The ebgine is cooled mainly through heat transfer and heat dissipation.The heat generated by the mixture burned in the engine must be transferred from the iron or aluminum cylinder to the waterin the water jacket.The outside of the water jacket dissipates some of the heat to the air surrounding it, but most of the heat is carried by the cooling water to the radiator for dissipation.When the coolant temperature in the system reaches 90°,the termostat valve open fully, its slanted edge shutting off
Fashion,which is as old as time and as new as tomorrow,is one of the most powerful forces in our lives .It influences what we wear,the way we talk,the foods we eat,the way we live,how and where we travel,what we travel,what we look at,and what we listen to.Fashion is what lead us todiscard a product that is still useful but is no longer ―in‖.It is also what makes us sometimes wear more clothes than we may actually need,and sometimes less than is needed to product us from the ccold or the sun. 流行是这样一种事物，是我们抛弃了还可以使用，但不再时髦的产品。有时候使我们穿比我们真正穿的衣服多，有时候比我们穿抵御严寒酷暑的少。 If there is one absolute constant pertaining to fashion,it is the fact that it is always changing-sometimes rapidly,sometimes slowly,but it is never static or dormant.This element of change is recognized in the definitions of fashion itself cited earlier,by the use of such words as ―prevailing‖or ―a given period of time.‖To ignore the element of change is like looking at a still photograph in place of a motion picture.The still tells you what is happening here and now ;the motion picture shows you what came before and what may lie ahead. 如果存在着一种符合流行的绝对永恒，那就是流行是永远变化着的这一事实，（这种变化）时快时慢，但绝不会固定下来或呈休止状态。 “Fashion is a social phenomenon which reflects the same continuing change that rides through any given age .‖Change in fashion ,he emphasized,‘correspond with the subtle and often hidden network of forces that operate on society……’ “流行是一种社会现象，它反映了任何特定年代同样都要经历的持续变化。‖他强调说：“流行变迁与那些作用于社会的影响力量所具有的微妙，而又常常是暗藏着的系统是一致的。”It is only in restrospect that fashion changes seem marked or sudden .Autually ,they come about as a result of a series of gradual shifts from one season to the next.For example ,when women’s skirts began inching up from midcalf in the 1960s,this gradual shortening was not particularly noticeable at first .It was only when skirts moved thigh-high,in the form of minis and micro-minis ,that people took notice of the approaching extreme.Similarly,when men begin to abandon ultrannarrow ties and suit lapels in favor of more and more width,the changs are not noticed at first. 只有当追溯过去的时候，流行的变迁才显得特别引人注目或突然，实际上，这些变迁的发生是从一个季节到另一个季节的一系列逐渐变化的结果。例如，女裙的逐渐变短的时候并没有被注意到，。 ………………………………………………………… Color can be the basis for a whole group or line .It is the first element to which consumers respond .People relate personally to color,usually either selecting or rejecting a garment beccause of its ccolor appeal.Therefore,designers must cconsider their customers and provide colors that are both appealing and flattering. 色彩是整个款式系列中的基本要素，它是能够引起顾客回应的第一要素。人们把色彩和个人联系起来，他们往往根据颜色来选择或拒绝一件衣服，因此设计师必须考虑他们的顾客，并且提供出令他们喜爱和满意的色彩，消费群体。 In clothing,neutrals such as beige,tan,brown,white ,gray,and black are even more popular than the ccolors just mentioned.The reason is probably that they present a pleasing background for the wearer without completing for attention. Neutrals are part of every season‖s fashion picture ,as either a strong fashion statement or a way to round out a color story. 在服装中，中色调例如灰中色，深褐，褐色，白灰和黑色，甚至还有比刚刚提到的更多的
Unit 1 1. 他相当足球明星的梦想随着时间的推移慢慢消退了。 His dream of becoming a football star faded out as time went by. 2. 一架波音747 飞机没有升到足够的高度以飞越那座高山，转瞬间一头撞向大山爆炸了。机上无人生还。 A Boeing 747 aircraft didn 't gain enough height to clear the mountain. In a twinkling, it crashed into the mountain and blew up. No one survived the accident. 3. 学生们可以很容易地获得图书馆的资源，所以他们应该充分地利用好图书馆。Students have easy access to the resources in the library, so they are supposed to make the best of it. 4. 当时世界上最豪华的游轮泰坦尼克号在她前往美国的途中撞到了冰山，结果轮船沉没在大西洋中，成百上千的人死于这场海难。 Titanic, the most luxurious ship in the world at that time , hit an iceberg when she was under way to the US. Consequently, the ship sank into the Atlantic Ocean and thousands of people died in this shipwreck. 5. 每天夏天，游客们都涌向这一著名的海滩。来此享受日光浴的游客像沙丁鱼一样挤满了海滩。 Every summer, all the tourists pour into this famous beach. They lie packed like sardines on the beach to enjoy the sunbathing. 6. 他们曾经到圣路易斯去过一次，对于哪里的新奇事物稍微知道一个大概，可是现在他们的光荣时代已经成过去了。他们从此自知没趣，再也不说话了，而且每逢这个毫不留情的机匠走过来的时候，他们就知道赶快躲开。 The have been to St. Louis once and have a vague general knowledge of its wonders, but the day of their glory is over now. They lapse into humble silence and learn to disappear when the ruthless engineer approaches. Unit 2 1. 有些网络专家认为因特网可以防止战争、减少污染，还能克服种种形式的不平等。Some cyber gurus claim that the Internet will prevent wars, reduce pollution, and combat various forms of inequality. 2. 不可否认，因特网可以增进交流，但他却无法消除战争，因为战争的爆发并不仅仅是由于不同种族间缺乏充分理解而引起的。 Although the Internet undeniably fosters communication, it will not put an end to war, since wars are by no means caused simply by the failure of different peoples to understand each other adequately. 3. 只有当网上的活动能够真正取代现实世界中的行为时，因特网才能帮助节约能源，减少污染。 The Internet can help reduce energy consumption and pollution only if doing things online genuinely displaces real-world activities. 4. 穷人不用因特网并不是因为他们买不起，而是因为他们缺乏必要的技能来有效地利用它，所以提高老百姓的文化水平要比给他们提供上网机会更有意义。 The poor are not shunning the Internet because they cannot afford it. The problem is that they lack the skills to exploit it effectively. Therefore, it makes more sense to aim for universal literacy than universal Internet access.
unit1 body 车身chassis 底盘enclosure外壳、套hood车棚、车顶sway 摇摆frame车架steering转向、操作brake 制动weld焊接rivet铆钉bolt螺钉washer垫圈vibration 振动stabilizer稳定器ride乘坐舒适性handling操作稳定性linkages转向传动机构plier钳子distributor分电器alternator交流发电机regulator调节器carburetor化油器radiator散热器、水箱defroster除冰装置sludge金属碎屑transmission变速器differential 差速器power train 传动系unitized body 承载式车身suspension system 悬架系统steering system 转向系braking system 制动系shock absorbers减震器control arms控制臂steering wheel 转向盘steering column转向管柱steering gears 转向器tie rod 横拉杆idler arm随动臂brake shoe制动蹄disc brake 盘式制动器drum brakes 鼓式制动器ignition system 点火系统exhaust system 排气系统lubrication system 润滑系oil filters 机油滤清器drive（or propeller）shaft传动轴universal joints 万向节dynamo发电机horn喇叭swived 旋转steering box转向器timing gear 正时齿轮bevel gear 锥齿轮mesh with与啮合leaf spring 钢板弹簧stub axle 转向节 unit2 longitudinal纵向的transverse横向的reciprocate往复spin旋转piston活塞ignite点火rub摩擦quart夸脱reservoir油箱mechanical机械的enclosed被附上的gallon加仑stroke冲程camshaft凸轮轴combustion燃烧disengaged脱离啮合的flywheel飞轮internal-combustion engine内燃机diesel-fuel柴油LPG=Liquefied Petroleum Gas液化石油气体CNG=Compressed natural gas压缩天然气spark ignition火花点火compression ignition压缩点火spark plug火花塞gas-turbine engine蒸汽机Stirling engine斯特灵发动机lubricating system润滑系统oil pan油底壳oil pump机油泵exhaust system排气系统emission-control system排放控制系统energy conversion能量转换air/fuel ratio空燃比connecting rod连杆TDC=Top Dead Center上止点BDC=Bottom Dead Center 下止点intake stroke进气冲程compression stroke压缩冲程power stroke作功冲程exhaust stroke排气冲程compression ratio压缩比lifter挺柱rocker摇臂retainer弹簧座seal密封件tappet 推杆lobe凸起gasket垫圈valve train配气机构cam follower气门挺柱rocker arm摇臂combustion chamber燃烧室intake valve进气阀exhaust valve排气阀valve stem气门杆valve cover气门室盖valve port阀口valve guide气门导管 unit3
INTERNAL COMBUSTION ENGINE 引擎燃烧室 1. principle of operation 原理 Engine and power : Engine is used to produce power. The chemical energy in fuel is converted to heat by the burning of the fuel at a controlled rate. This process is called combustion. If engine combustion occurs with the power chamber. ,the engine is called internal combustion engine. If combustion takes place outside the cylinder, the engine is called an external combustion engine. Engine used in automobiles are internal combustion heat engines. Heat energy released in the combustion chamber raises the temperature of the combustion gases with the chamber. The increase in gas temperature causes the pressure of the gases to increase. The pressure developed within the combustion chamber is applied to the head of a piston to produce a usable mechanical force, which is then converted into useful mechanical power. 译: 引擎和能量: 引擎为汽车提供能量，燃料的化学能通过燃烧，转化为热能，这个过程叫燃烧。假如燃烧在燃烧室，这样的发动机叫内燃机。假如燃烧在气缸外，这样的发动机叫外燃机。 用在汽车上的一般是内燃机，热能在燃烧室释放，燃烧室气体温度升高。气体温度的升高使气体的压力曾加，燃烧室内的高压气体作用在活塞头部产生可以利用的化学能，化学能转化为机械能。 Engine T erms : Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn. The power stroke “uses up” the gas , so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture :this control of gas movement is the duty of the valves ;an inlet valve allows the new mixture to enter at the right time and an exhaust valve lets out the burnt gas after the gas has done its job. Engine terms are : TDC(Top Dead Center):the position of the crank and piston when the piston is farther away from the crankshaft. BDC(Bottom Dead Center):the position of the crank and piston when the piston is nearest to the crankshaft. Stroke : the distance between BDC and TDC; stroke is controlled by the crankshaft. Bore : the internal diameter of the cylinder. Swept volume : the volume between TDC and BDC Engine capacity : this is the swept volume of all the cylinder e.g. a four-stroke having a capacity of two liters(2000cm) has a cylinder swept volume of 50cm. Clearance volume: the volume of the space above the piston when it is at TDC. Compression ratio = (swept vol + clearance vol)\(clearance vol) Two-stroke : a power stroke every revolution of the crank.