Chapter 1 Enging types and their operation
1.1 Introduction and historical perspective
1．内燃机的目的是从蕴含在燃料中的化学能中得到机械动力。
The purpose of internal combustion engines is the production of mechanical power from the chemical energy contained in the fuel .
2．有别于外部燃烧机器，在内燃机中，能量是在机器内部燃烧或氧化燃料释放出来的。
In internal combustion engines ,as distinct from external combustion engines, this energy is released by burning or oxidizing the fuel inside the engine.
3．功的转移，提供了需要的动力输出，发生在工作流体和机器的机械部件之间。
The work transfers which provide the desired power output occur directly between these working fluids and the mechanical components of the engine.
4．实际上正是由于燃烧发生在机器做功部件内部才使它们的设计和运行特征从根本上有别于其他类型的机器。
It is the fact that combustion takes places inside the work-producing part of these engines that makes their design and operating characteristics fundamentally different from those of other types of engine.
5.水，升成蒸汽，介入到由燃烧燃料产生的燃气和作功活塞膨胀之间。
Water,raised to steam ,was interposed between the combustion gases produced by burning the fuel and the work-producing piston-in-cylinder expander.
6.早期面向市场开发的机器是在常压下燃烧煤气空气混合物，燃烧前没有压缩。
The early engines developed for commercial use burned coal-gas air mixtures at atmospheric pressure--there was no compression before combustion.
7.煤气和空气在前半个活塞冲程被吸入缸内。然后用火花点燃工质，压力升高，燃烧的气体在后半个活塞冲程将动力传递给活塞。循环以排气冲程结束。
Gas and air were were drawn into the cylinder during the first half of the stroke.The charge was then ignited with a spark, the pressure increased, and the burned gases then delivered power to the piston for the second half of the stoke.
8.更成功的改进利用早期向外冲程时工质燃烧导致的压力升高来加速自由活塞和齿条组，由于它的运动将在缸内形成一个真空。于是大气压推动活塞向内运动，伴随齿条通过一个滚动离合啮合到输出轴上。
A more successful development used the pressure rise resulting from combustion of the fuel-air charge early in the outward stroke to accelerate
a free piston and rack assembly so its momentum would generate a vacuum in the cylinder.
9.这一偶然发现对奥拓四冲程机专利的合法性提出了质疑。在德国奥拓专利被宣布非法。
This charge discovery cast doubt on the validity of Otto' s own patent for this concept, and in Germany it was declared invalid.
10.尽可能大的气缸容积和尽可能小的边界面积；尽可能快的做工速度；尽可能高的膨胀比；膨胀之初尽可能高的压力。
The largest possible cylinder volume with the minimum boundary surface.The greatest possible working speed.The greatest possible expansion ratio. The greatest possible pressure at the beginning of expansion.
11.前两个条件保证工质的热量损失达到最小。第三个条件可认为后燃气体膨胀越大获取的功越多。第四个条件可认为初始压力越高越有可能产生更大的膨胀，在整个过程中产生更高的压力，两者都会导致更多的功输出。
The first two conditions hold heat losses from the charge to a minimum. The third condition recognizes that the greater the expansion of the postcombustion gases, the greater the work extracted.The fourth condition recognizes that higher pressures throughout the process, both resulting in greater work transfer.
12．他的专利利用将液体燃料喷入仅由压缩而加热的空气中触发燃烧使效率高出其他类型内燃机的两倍。更高的压缩比，不存在爆震或敲缸的现象成为可能。
His concept of initiating combustion by injecting a liquid fuel into air heated solely by compression permitted a doubling of efficiency over other internal combustion engines.Much greater expansion ratios, without detonation or knock now possible.
13.早期产生机械动力的机器燃烧气体。汽油和原油中的轻质成分在十九世纪末才有，开发出各种化油器来蒸发燃料将其与空气混合。The earliest engines used for generating mechanical power burned gas. Gasoline, and lighter fractions of crude oil, become available in the late 1800s and various types of carburetors were developed to vaporized the fuel and mix it with air.
14.然而由于原油短缺要满足1907至1915年之间五倍汽油的需求，（汽油）从原油中的产出必须提高。
However, a serious crude oil shortage developed, and to meet the fivefold increase in gasoline demand between 1907 and 1915, the yield from crude had to be raised.
15开发了热裂解工序，在那里重油在高压下被加热分解为不复杂、更易挥发的化合物。这些热裂解汽油满足了需求，但它们的高沸点出现寒冷气候的启动问题。
A thermal cracking process was developed whereby heavier oils were heated under pressure and decomposed into less complex more volatile compounds. These thermally cracked gasolines satisfied demands, but their higher boiling point range created cold weather starting problems. 16.Houdry 发现蒸发的油在450至480度的温度下经过活性催化剂可转化为高质量汽油，比热裂解的产出高得多。这些进步以及其它改进使具有更好抗敲缸性能的燃料可以大量生产。
Houdry found that vaporized oils passed over an activated catalyst at 450 to 480 C were convented to high-quality gasoline in much higher yields than was possible with thermal cracking.These advances, and others, permitted fuels with better and better thermal antiknock properties to be produced in large quantities.
17.在过去的三十年中，要改变的新因素变得非常重要并严重影响机器的设计和运行。这些因素是，其一、需要控制车辆对城市空气的污染，其二、需要对车辆燃油消耗进行大幅度改善。
During the past three decades, new factors for change have become important and now significantly affect engine design and operation.These factors are, first, the need to control the automotive contribution to urban air pollution and, second, the need to achieve significant improvements in automotive fuel consumption.
18.大幅度降低SI排气系统的废气并考虑到含铅抗敲缸添加剂的毒害使得无铅汽油作为主要车辆燃料重新返回市场。含铅汽油中的最大
含铅量大幅降低。排放控制的要求以及燃料的改进使内燃机设计和运行上发生了很大改变。
Both the use of catalysts in spark-ignition engine exhaust systems for emissions control and concern over the toxicity of lead antiknock additives have resulted in the reappearance of unleaded gasoline as a major part of the automotive fuels market. Also, the emission-control requirements and these fuel developments have produced significant changes in the way internal combustion engines are designed and operated.
19.原油价格猛涨到1970年的几倍，（人们）开始担心石油的长期可持续性。大幅度提高内燃机效率的压力明显增加。然而，排放控制的要求使改善燃料消耗举步艰难。
During the 1970s the price of crude petroleum rose rapidly to several times its cost in 1970, and concern built up regarding the longer-term availability of petroleum. Pressures for substantial improvements in internal combustion engine efficiency have become very substantial indeed. Yet emission-control requirements have made improving engine fuel consumption more difficult.
20.人们可能认为经过了一个多世纪，内燃机（技术）已经达到顶峰，没有进一步改善的潜力。实际并非如此。传统内燃机在效率、功率、排放水平方面都在不断改善。
It might be thought that after over a century of development, the internal combustion engine has reached its peak and little potential for further improvement remains. Such is not the case. Conventional spark-ignition and diesel engines continue to show substantial improvements in efficiency, power, and emission control.
21.新材料的出现为降低重量、成本和热损失提供了可能。其它类型的内燃机，比如可使用多种燃料的分层充量内燃机，有可能会更有吸引力并得到大量生产。
New materials now becoming available offer the possibilities of reduce engine weight, cost , and heat losses, and of different and more efficient internal combustion engine systems. Alternative types of internal combustion engines, such as the stratified-charge with its wider fuel tolerance, may become sufficiently attractive to reach large-scale production.
22.未来内燃机的改进潜力无穷，但这将对汽车工程师提出艰巨的挑战。随着我们对内燃机知识的不断拓宽，这一切都会变为可能。The engine development opportunities of the future are substantial. While they present a formidable challenge to automotive engineers, they will be made possible in large part by the enormous expansion of our knowledge engine processes.
1.2 Engine classifications
所有这些特征都很重要，它们显示了现有内燃机设计的范围。由于我们想从根本上了解内燃机的运行和排放特征，点火方式被选为最主要的分类特点。不同点火方式（火花点火或压缩点火）伴随使用燃料、混合物准备方法、燃烧室设计、负载控制、燃烧过程的详细过程、排放、运行特点等重要特征。
All these distinctions are important and they illustrate the breadth of engine designs available. Because this book approaches the operating and emissions characteristics of internal combustion engines from a fundamental point of view, the method of ignition has been selected as the primary classifying feature. From the method of ignition-spark-ignition or compression-ignition --follow the important characteristics of the fuel used, method of mixture preparation, combustion chamber design,method of load control, details of the combustion process, engine emissions, and operating characteristics.
1.3 Engine operation cycles
1. 书中主要讲了往复式内燃机，在那儿活塞在缸内前后运动，通过连杆和曲柄装置将动力传送给驱动轴。曲柄稳定的转动致使活塞循环运动。活塞在上止点和下至点停止运动，这时分别对应容积最小和最大。
Most of this book is about reciprocating engines, where the piston moves back and forth in a cylinder and transmits power through a connecting rod and crank mechanism to the drive shaft. The steady
rotation of the crank produces a cyclical piston motion. The piston comes to the top-center crank position and bottom-center crank position when the cylinder volume is a minimum or maximum, respectively.
2.最小气缸容积称为挤气间隙。最大和最小容积之差为扫过的容积。最大和最小容积之比是压缩比。
The minimum cylinder volume is called the clearance volume Vc. The volume swept out by piston, the difference between the maximum or total volume Vt and the clearance volume, is called the displaced or swept volume Vd. The ratio of maximum volume to minimum volume is the compression ratio r.
3. 多数往复式内燃机以四冲程循环的形式运行。每缸需要四个活塞冲程（两个曲轴循环）完成一系列事件，输出一个做功冲程。
The majority of reciprocating engines operate on what is known as the four-stroke cycle. Each cylinder requires four strokes of its piston---two revolutions of the crankshaft---to complete the sequence of events which produces one power strokes
4. 进气冲程开始于活塞上止点，结束于活塞下至点，该冲程将新鲜混合气吸入缸内。为了提高进气量，进气阀门在冲程开始之前打开，冲程结束之后关闭。
An intake stroke, which starts with the piston at TC and ends with the piston at BC, which draws fresh mixture into the cylinder.To increase the
mass inducted, the inlet valve opens shortly before the stroke starts and close after it ends.
5. 当进排气门都关闭后缸内混合气被压缩到初始体积的一小部分。压缩冲程将要结束时，开始燃烧，缸内压强迅速升高。
A compression stroke, when both valves are closed and the mixture inside the cylinder is compressed to a small fraction of its initial volume. Toward the end of the compression stroke, combustion id initiated and the cylinder pressure rise more rapidly.
6.做功冲程开始于活塞上止点，结束于下至点，高温高压气体推动活塞向下，迫使曲柄旋转。做功冲程作用在活塞上的功是压缩冲程活塞做功的五倍。当活塞接近下至点，排气门打开触发了排气过程，并将缸内压力降至接近排气压力。
A power stroke, or expansion stroke, which starts with the piston at TC and ends at BC as the high-temperature, high-pressure, gases push the piston down and force the crank to rotate. About five times as much work is done on the piston during the power stroke as the piston had to do during compression. A the piston approaches BC the exhaust valve opens to initiate the exhaust process and drop the cylinder pressure to close to the exhaust pressure.
7.由于缸内压力可能明显高于排气压力，又因活塞向上止点运动时气体被扫出。当活塞接近上止点时进气门打开。上止点后排气门关闭，循环重新开始。
Because the cylinder pressure may be substantially higher than the exhaust pressure, then as they are swept out by the piston as it moves toward TC. As the piston approaches TC the inlet valve opens. Just after TC the exhaust valve closes and the cycle starts again.
8.根据它的发明者Nicolaus Otto,他于1876年设计出第一台以这一原理运行的内燃机，常命名为Otto循环，人们更愿意用直观的四冲程专业词（来命名这一循环）。
Though often called the Otto cycle after its inventor, Nicolaus Otto, who built the first engine operating on these principles in 1876, the more descriptive four-stroke nomenclature is preferred.
9.对于每一个气缸，四冲程循环需要两个曲轴循环输出一个做功冲程。对给定尺寸内燃机为了获得更高动力输出，人们开发了简单气门设计、两冲程循环。两冲程可应用于SI和CI机。
The four-stroke cycle requires, for each engine cylinder, two crankshaft revolutions for each power stroke. To obtain a higher power output from a given engine size, and a simpler valve design, the two-stroke was developed. The two-stroke cycle is applicable to both SI and CI engines.
10.缸套内的气门，由活塞的运动打开、关闭，在活塞接近BC时控制着进、排气流。
Ports in the cylinder liner, opened and closed by the piston motion , control the exhaust and inlet flows while the piston is close to BC.
11.压缩冲程开始于进排气口均关闭，随后压缩缸内工质将新鲜工质吸入曲轴箱。当活塞趋近TC，燃烧开始。
A compression stroke, which starts by closing the inlet and exhaust ports, and then compresses the cylinder contents and draws fresh charge into the crankcase .As the piston approaches TC, combustion is initiated.
12.直到活塞接近BC，膨胀冲程的做功仍和四冲程循环类似，接着排气口和进气口相继打开。大部分已燃气体在扫气过程排出气缸。当进气口打开后，在曲轴箱内被压缩的新鲜工质流入气缸。活塞和气口通常做成特殊形状将进入的工质偏转，避免直接流进排气口，以便有效扫除残余气体。
A power or expansion stroke, similar to that in the four-stroke cycle until the piston approached BC, when first the exhaust ports and then the intake ports are uncovered. Most of the burnt gases exit the cylinder in an charge which has been compressed in the crankcase flows into the cylinder. The piston and the ports are generally shaped to deflect the incoming charge from flowing directly into the exhaust ports and to achieve effective scavenging of the residual gases.
13.曲轴转动一周，完成一个循环，输出一个做功冲程。然而，很难将扫过的容积完全充入新鲜工质，一些新鲜工质在扫气过程直接流出气缸。
Each engine cycle with one power stroke is completed in one crankshaft revolution. However, it is difficult to fill completely the displaced volume
with fresh charge, and some of the fresh mixture flows directly out of the cylinder during the scavenging process.
Chapter 10 Combustion in compression-ignition engines 10.1 Essential feature of processes
The essential feature of compression ignition engine combustion process can be summarized as follows. Fuel is injected by the fuel-injection system into the engine cylinder toward the end of the compression stroke, just before the desired start of combustion.
柴油机燃烧过程的基本特征归结如下：燃料由喷油系统在压缩接近结束、燃烧开始之前喷入气缸。
Figures 1-17,18 and 19 illustrate the major components of common diesel fuel injection systems. The l iquid fuel，usually injected at high velocity as one or more jets through small orifices or nozzles in the injector tip, atomizes into small drops and penetrates into the combustion chamber.
图17—19显示一般柴油喷射系统的主要构成部分。液体燃料，通常是一束或多束射流通过喷油器顶端的小孔或喷嘴高速喷入，雾化成小油滴贯穿燃烧室。
The fuel vaporizes and mixes with the high temperature high pressure cylinder air. Since the air temperature and pressure are above the fuel’s ignition point, spontaneous ignition of portions of the already-mixed fuel and air occurs after a delay period of a few crank angle degrees.
燃料蒸发与缸内高温高压空气混合。当空气温度和压强高压燃料着火点时，部分已经混合好的燃气经历几个曲轴转角的滞燃期后自发着火。
The cylinder pressure increase s as combustion of the fuel-air mixture occurs. The consequent compression of the unburned portion of the charge shortens the delay before ignition for the fuel and air which has mixed to within combustible limits, which then burns rapidly. It also reduces the evaporation time of the remaining liquid fuel.
随着混合物的燃烧，缸内压强升高。未燃工质的继续压缩缩短了已经混合达到可燃极限的油、气着火前的滞燃期。也缩短了剩余液体燃料的蒸发时间。
Injection continues untile the desired amount of fuel has entered the cylinder. Atomization, vaporization, fuel-air mixing, and combustion continue until essentially all the fuel has passed through each process.
喷油仍在继续，直到期望油量全都进入气缸。雾化、蒸发、油气混合仍在继续，直到所有燃料都经历了每一个过程。
In addition, mixing of the air remaining in the cylinder with burning and already burned gases continues throughout the combustion and expansion processes.
另外，缸内剩余空气与正在燃烧和已经燃烧的气体的混合过程经持续到整个燃烧和膨胀阶段。
It will be clear from this summary that the compression-ignition combustion process is extremely complex. The details of the process depend on the fuel-injection system, and on the engine’s operating conditions. It is an unsteady, heterogeneous, three-dimensional combustion process.
在总结中可以清楚看到压缩点火的燃烧过程极为复杂。具体的过程取决于喷油系统、运行工况。是不稳定、不均匀、3维的燃烧过程。While an adequate conceptual understanding of diesel engine combustion has been developed, to date an ability to describe many of the critical individual processes in a quantitative manner is lacking.
人们已经对柴油机有了足够的概念性理解，目前仍然缺乏定量描述很多关键个别过程的能力。
Some important consequences of this combustion process on engine operation are the following:
下面是燃烧过程中出现的一些重要结果：
1.since injection commences just before combustion starts, there is no
knock limit as in the spark-ignition engine resulting from spontaneous ignition of the premixed fuel and air in the end-gas. Hence a higher engine compression ratio can be used in the compression-ignition engine, improving its fuel conversion efficiency relative to the SI engine.
由于喷油是在燃烧开始前进行的，不存在象火花点火机中预混燃料在气体末端自燃导致的敲缸极限。因此在压燃机中可以用更高的压缩比，相对于SI机来说提高了燃油转化效率。
2.since injection timing is used to control combustion timing, the delay
period between the start of injection and start of combustion must be kept short (and reproducible). A short delay is also needed to hold the maximum cylinder gas pressure below the maximum the engin can tolerate. Thus, the spontaneous ignition characteristics of the fuel-air mixture must be held within a specified range. This is done by requiring that diesel fuel have a cetane number (a measure of the ease of ignition of that fuel in a typical diesel environment) above a certain value.
由于利用喷油时间控制燃烧正时，喷油始点和燃烧始点之间的滞燃期一定要短（具有可重复性）。需要一个短滞燃期来保证缸内最大压力低于机器所能承受的最大压力。因此混合气的自燃特征必须控制在特定范围。这需要柴油的辛烷值（在一般的柴油机环境下衡量燃料点火难易程度的值）要高于某一个值。
3.since engine torque is varied by varying the amount of fuel injected
per cycle with the engine air flow essentially unchanged, the engine can be operated unthrottled. Thus, pumping work requirements are low, improving part-load mechanical efficiency relative to the SI engine.
既然扭矩是通过改变每循环喷入的油量（空气流量基本不变）来改变，机器可在无节流情况下运行。因此需要的泵气功低，相比SI机改善了部分负荷下的机械效率。
4.As the amount of fuel injected per cycle is increased, problems with
air utilization during combustion lead to the formation of excessive amounts of soot which cannot be burned up prior to exhaust. This excessive soot or black smoke in the exhaust constrains the fuel/air ratio at maximum engine power to values 20 percent (or more)lean of stoiciometric. Hence, the maximum indicated mean effecitve pressure (in a natrally aspirated engine is) is lower than values for an equivalent spark-ignition engine.
随着每循环喷入油量的增加，燃烧时空气的利用问题导致大量碳烟生成，排气前无法充分燃烧。废气中过量的碳烟或黑烟限制着最大功率时的燃空比比理论空燃比低20%。因此，最大指示平均有效压强与同等火花点火机相比要低。
5.Because the diesel always operates with lean fuel/air ratios ( and at
part load with very lean fuel/air ratios), the effective value of over the expansion process is higher than in a spark-ignition engine. This gives a higher fuel conversion efficiency than the spark-ignition engine，for a given expansion ratio.
由于柴油机总是工作在较稀的燃空比下（在部分负荷下燃空比更低），膨胀过程的有效 值比在火花点火机中的高。对给定压缩比，燃油转化效率比火花机高。
The major problem in diesel combustion chamber design is achieving sufficienthly rapid mixing between the injected fuel and the air in the cylinder to complete combustion in the appropriate crank angle inerval close to top-center. The foregoing discussion indicates (and more detailed analysis will confirm) that mixing rates control the fuel burning rate.
柴油燃烧室设计的主要问题是如何将喷入的燃油和空气快速混合在接近上止点的适当曲轴转角范围完成燃烧。接下来的讨论可见混合速率控制着燃油燃烧速率。
Commercial diesel egines are made with a very large range of cylinder sizes, with cylinder bores varing from about 70 to 900 mm. The mean piston speed at maximum rated power is approximately constant over this size range (see Sec. 2.2), so the maximum rated engine speed will be inversely proportional to the stroke [ see Eq. (2.9)].
产品柴油机尺寸范围很大，缸径在70到900 毫米范围。在这个范围内最大额定功率下活塞平均速度接近常数，因此最大额定速度与冲程成反比。
For a fixed crank angle interval for combustion (of order 40 to 50 to maintain high fuel conversion efficiency), the time available for combustion will, therefore, scale with the stroke. Thus, at the small end of
the diesel engine size range, the mixing between the injected fuel and the aire must take place on a time scale some 10 times shorter than in the engines at the large end of this range.
燃烧在固定的曲轴转角区间（40到50度以保证高的燃油转化效率），燃烧时间将用冲程衡量。因此，小尺寸柴油机中，喷入的燃油和空气必须在大尺寸柴油机混合时间的十分之一内完成混合。
It would be expected, therefore, that the design of the engine combustion chamber (including the inlet port and valve) and the fuel-injection system would have to change substantially over this size range to provide the fuel and air motion inside the cylinder required to achieve the desired fuel-air mixing rate.
因此，希望对不同尺寸机器在燃烧室和喷油系统设计时做相应变化，以得到所需要的运动，实现期望的燃空混合速率。
As engine size decreases, more vigorous air motion is required while less fuel jet penetration is necessry. It is this logic, primarily, that leads to the different diesel combustion chamber designs and fuel injection systems found in practice over the large size range of commercial diesel engines.
随着机器尺寸的减小，需要更强烈的气流运动和更短的油束贯穿距离。正是这样的逻辑关系，我们看到产品柴油机在不同尺寸范围内具有不同的燃烧室设计和喷油系统。
1、应力和应变 应力和应变的概念可以通过考虑一个棱柱形杆的拉伸这样一个简单的方式来说明。一个棱柱形的杆是一个遍及它的长度方向和直轴都是恒定的横截面。在这个实例中，假设在杆的两端施加有轴向力F，并且在杆上产生了均匀的伸长或者拉紧。 通过在杆上人工分割出一个垂直于其轴的截面mm，我们可以分离出杆的部分作为自由体【如图1(b)】。在左端施加有拉力P，在另一个端有一个代表杆上被移除部分作用在仍然保存的那部分的力。这些力是连续分布在横截面的，类似于静水压力在被淹没表面的连续分布。 力的集度，也就是单位面积上的力，叫做应力，通常是用希腊字母，来表示。假设应力在横截面上是均匀分布的【如图1(b)】，我们可以很容易的看出它的合力等于集度，乘以杆的横截面积A。而且，从图1所示的物体的平衡，我们可以看出它的合力与力P必须的大小相等，方向相反。因此，我们可以得出 等式(1)可以作为棱柱形杆上均匀应力的方程。这个等式表明应力的单位是，力除以面积。当杆被力P拉伸时，如图所示，产生的应力是拉应力，如果力在方向是相反，使杆被压缩，它们就叫做压应力。 使等式(1)成立的一个必要条件是，应力，必须是均匀分布在杆的横截面上。如果轴向力P作用在横截面的形心处，那么这个条件就实现了。当力P 没有通过形心时，杆会发生弯曲，这就需要更复杂的分析。目前，我们假设所有的轴向力都是作用在横截面的形心处，除非有相反情况特别说明。同样，除非另有说明，一般也假设物体的质量是忽略的，如我们讨论图1的杆一样。
轴向力使杆产生的全部伸长量，用希腊字母δ表示【如图1(a)】，单位长度的伸长量，或者应变，可以用等式来决定。 L是杆的总长。注意应变ε是一个无量纲的量。只要应变是在杆的长度方向均匀的，应变就可以从等式(2)中准确获得。如果杆处于拉伸状态，应变就是拉应变，代表材料的伸长或者 ，那么应变就是压应变，这也就意味着杆上临近的横截面是互相靠近的。 当材料的应力和应变显示的是线性关系时，也就是线弹性。这对多数固体材料来说是极其重要的性质，包括多数金属，塑料，木材，混凝土和陶瓷。处于拉伸状态下，杆的应力和应变间的线性关系可以用简单的等式来表示。E 是比例常数，叫做材料的弹性模量。 注意E和应力有同样的单位。在英国科学家托马斯·杨(1773 ~ 1829)研究杆的弹性行为之后，弹性模量有时也叫做杨氏模量。对大多数材料来说，压缩状态下的弹性模量与处于拉伸时的弹性模量的一样的。 2、拉伸应力应变行为 一个特殊材料中应力和应变的关系是通过拉伸测试来决定的。材料的试样通常是圆棒的形式，被安置在测试机上，承受拉力。当载荷增加时，测量棒上的力和棒的伸长量。力除以横截面积可以得出棒的应力，伸长量除以伸长发生方向的长度可以得出应变。通过这种方式，材料的完整应力应变图就可以得到。 图1所示的是结构钢的应力应变图的典型形状，轴向应变显示在水平轴，对应的应力以纵坐标表示为曲线OABCDE。从O点到A点，应力和应变之间是直接成比例的，图形也是线性的。过了A点，应力应变间的线性关系就不存
Materials Science and Engineering arc welding 电弧焊 calcinations 煅烧 casting 熔铸 ceramic 陶瓷 chemical properties 化学性能 cold brittleness 低温脆性 colour liquid crystals 彩色液晶 congruent compound 合熔化合物 constant-deformation tests 定变形试验 Creep Strength 潜变强度 crystal pattern 晶体结构 data quartz fiber 数据石英光纤 die casting 拉模铸造 drawing & stamping 延轧 Dynamics of Forging System 锻压系统动力学 Edge Finish 边缘处理 Engineering Materials 工程材料 nano-material 纳米材料 ceramic 陶瓷 polymer 集合物 composite material 复合材料 biomaterial 生物材料semiconductor 半导体 conductor 导体 insulator 绝缘体 synthetic fabrics 合成纤维microstructures 显微结构 periodic table 周期表 Equipment for Heating Processing 热处理设备 Fatigue Test 疲劳测试 Features of Metal 金属的特性 Ferrous & Non Ferrous Metal 铁及非铁金属 forging 锻造 foundry 铸造 High Polymer Material & Processing 高分子材料及加工Impact Test 冲击测试 Intermetallic compound 金属间化物 Ionic Solids 离子晶体 Magnetic Transformation 磁性变态 Mechanic Testing of Engineering Materials 工程材料力学性能的测定Mechanical Property of Metal 金属机械性能 Metal Cutting Machine Tool 金属切削工具 Metal Erosion & Protection 金属腐蚀及防护 Metal Material Science 金属材料学 Metallic Solids 金属晶体Metallographic Techniques 金相技术Metallography 金属学 Metallography & Heat Treatment 金属学与热处理
Unit 1 1. sedimentary rocks沉积岩 2. petroleum reserves石油储备 3. internal combustion engines内燃机 4. the boiling point 沸点 5. fatty substance脂肪物质 6. in minor quantities少量 7. petroleum fractions石油馏分8. inflammable vapors易燃蒸汽 9. geologic formations地质结构10. in the territory of在……领土 11. chemical change 化学变化12. petroleum seepage 油苗 13. petroleum stores 油藏14. petroleum reserves 石油储量 15.medieval times 中世纪16.Industrial Revolution 工业革命 17.fossil fuel 矿物燃料 Unit 2 1. employment market 就业市场 2. video conferencing technology视频会议技术 3. job interview 求职面试 4. nine out of ten十有八九 5. aptitude test能力测试 6. recruitment method招聘方法 7. face-to-face encounter面对面接触8.personality questionnaires个性问卷调查 9. psychological test 心理测试10. customer complains 顾客投诉 https://www.doczj.com/doc/35467169.html,e third from botton 倒数第三12 curriculum vitae 简历 Unit 3 1. multiple users 多用户 2. virtual assistant虚拟助手 3. human-machine interface 人机界面 4. speech synthesizer语音合成器 5. real time实时 6. information retrieval信息检索 7. air flight schedule飞机飞行时刻表8. weather forecast天气预报 9. speech recognition 语音识别10. stock quotes股市行情；股票报价 11. Mandarin Chinese普通话，官话12.data dumping 数据转储 Unit 4 1. genetic engineering基因工程 2. organic solvents有机溶剂 3. raw material原材料 4. sulfur dioxide 二氧化硫 5. landfill deposit垃圾填埋 6. garage sale旧物销售 7. information age信息时代8. lead compound铅化合物 9. municipal solid waste 固体生活垃圾10. eco-industrial park生态工业园 Unit 6 1. quantum mechanics量子力学 2. general theory of relativity 广义相对论 3. physical laws 自然法则 4. square of the distance 距离的平方 5. in principle原则上，基本上 6. in isolation孤立地 7. in one go一口气，一下子，一举8. Newton’s theory of gravity牛顿的引力理论9.partial theories 局部理论10.gravitational force 引力 11.the initial state of the universe宇宙初始状态12.the theory of relativity 相对论 13.be（intersely）proportional to 与...成反比 Unit 7 1.quick fixes权宜之计 2. go by the book 照章办事 3. close to the vest谨慎小心 4.corporate culture企业文化 5. Old Boy network老同学人脉网 6. to the point切题的（地），切中的（地） 7. social status社会地位 8. sense of humor幽默感 9. put on an impressive appearance装腔作势10.pull rank on利用职权强迫命令；仗势欺人11.be superior to 优于... 12.lip service 口头上应付的话 13.sense of humor幽默感14.make sense 有道理，有意义 15.memo 备忘录
小议科技英语翻译技巧 科技文体崇尚严谨周密，概念准确，逻辑性强，行文简练，重点突出，句式严整，少有变化，常用前置性陈述，即在句中将主要信息尽量前置，通过主语传递主要信息。科技文章文体的特点是：清晰、准确、精练、严密。那末，科技文章的语言结构特色在翻译过程中如何处理，这是进行英汉科技翻译时需要探讨的问题。现分述如下： 一、大量使用名词化结构 大量使用名词化结构（Nominalization）是科技英语的特点之一。因为科技文体要求行文简洁、表达客观、内容确切、信息量大、强调存在的事实。而非某一行为。 Archimedes first discovered the principle of displacement of water by solid bodies. 阿基米德最先发展固体排水的原理。 句中of displacement of water by solid bodies 系名词化结构，一方面简化了同位语从句，另一方强调displacement 这一事实。 The rotation of the earth on its own axis causes the change from day to night. 地球绕轴自转，引起昼夜的变化。 名词化结构the rotation of the earth on its own axis 使复合句简化成简单句，而且使表达的概念更加确切严密。 If you use firebricks round the walls of the boiler, the heat loss, can be considerably reduced. 炉壁采用耐火砖可大大降低热耗。 科技英语所表述的是客观规律，因之要尽量避免使用第一、二人称；此外，要使主要的信息置于句首。 Television is the transmission and reception of images of moving objects by radio waves. 电视通过无线电波发射和接受活动物体的图象。 名词化结构the transmission and reception of images of moving objects by radio waves 强调客观事实，而"谓语动词则着重其发射和接受的能力。 二、广泛使用被动语句 根据英国利兹大学John Swales 的统计，科技英语中的谓语至少三分之一是被动态。这是因为科技文章侧重叙事推理，强调客观准确。第一、二人称使用过多，会造成主观臆断的印象。因此尽量使用第三人称叙述，采用被动语态，例如：Attention must be paid to the working temperature of the machine.应当注意机器的工作温度。而很少说：You must pay attention to the working temperature of the machine .你们必须注意机器的工作温度。此外，如前所述，科技文章将主要信息前置，放在主语部份。这也是广泛使用被动态的主要原因。试观察并比较下列两段短文的主语。 We can store electrical energy in two metal plates separated by an insulating medium. We call such a device a capacitor, or a condenser, and its ability to store electrical energy capacitance .It is measured in farads. 电能可储存在由一绝缘介质隔开的两块金属极板内。这样的装置称之为电容器，
Resistor A resistor is a two-term inal electro nic comp onent that opposes an electric curre nt by produc ing a voltage drop betwee n its termi nals in proport ion to the curre nt, that is ,in accorda nee with Ohm ' s law :V=IR .The electrical resistance R is equal to the voltage drop V across the resistor divided by the current I through the resistor. Resistors are used as part of electrical networks and electronic circuits. 电阻器是一个二端口电子元件，电阻是阻止电流流动，通过按比例产生其端子之间的电压降的电流，也就是 说，根据欧姆定律:V = IR。电阻R等于电压降V除以通过电阻的电流I。电阻作为电子网络和电子电路的一部分。 Tran sistor In electro nics, a tran sistor is a semic on ductor device commo nly used to amplify or switch electro nic sig nals . A tran sistor is made of a solid piece of a semic on ductor material , with at least three term in als for connection to an exter nal circuit. A voltage or curre nt applied to one pair of the tran sistor ' s term in als cha nges the curre nt flow ing through ano ther pair of term in als. Because the con trolled curre nt can be much larger tha n the con trolli ng curre nt, the tran sistor provides amplificati on of a sig nal. The tran sistor is the fun dame ntal buildi ng block of moder n electro nic devices, and is used in radio, telepho ne, computer and other electr onic systems. Some tran sistors are packaged in dividually but most are found in in tegrated circuits. 在电子技术中，晶体管是一种，常用来放大或进行开关控制电子信号的半导体器。晶体管是 由一块固体半导体材料制成的，且至少有三个终端与外部电路连接。电压或电流适用于一双 晶体管的终端改变目前流经的另一对终端。因为受控电流可以远大于控制电流，晶体管提供 信号的放大。晶体管是构建现代电子设备的基本单元，并在收音机，电话，计算机和其它电子系统被使用。一些晶体管被单独包装，但大多数都在集成电路中。 Tran sformer A transformer is a device that transfers electrical energy from one circuit to anther through in ductively coupled electrical con ductors . A cha nging curre nt in the first circuit creates a cha nging magn etic field; in turn, this magn etic field in duces a cha nging voltage in the sec ond circuit. By add ing a load to the sec on dary circuit, one can make curre nt flow in the tran sformer, thus tran sferri ng en ergy from one circuit to the other. 变压器是一种通过感应耦合将电能从一个电路传输到另一个电路的装置。在第一电路中的一 个变化的电流创建一个不断变化的磁场；反过来，这个磁场诱导第二个电路中的电压变化。 通过向二次回路中增加负载，使电流在变压器中流动，从而将能量从一个电路传递到另一个 电路中。 Relay A relay is an electrical switch that ope ns and closes un der the con trol of ano ther electrical circuit . In the origi nal form ,the switch is operated by an electromag net to ope n or close one or many sets of con tacts. It was inven ted by Joseph Henry in 1835. Because a relay is able to con trol an output circuit of higher power tha n the in put circuit ,it can be con sidered to be, in a broad sen se, a form of an electrical amplifier. 继电器是一种电子开关，控制另一个电路的打开和关闭。在原始形式中，该开关是由一个电磁铁操作，打开或关闭一个或多个触点。它是由约瑟夫亨利在1835年发明的。由于继电器 能够控制比输入电路功率更高的输出电路，广义上说，它可以被认为是电子放大器的一种形 式。 Types of circuits In any circuit where the on ly oppositi on to the flow of electr ons is resista nee , there is a defi nite relati on
各专业课程英文翻译(精心整理) 生物及医学专业课程汉英对照表 应用生物学 Applied Biology 医学技术 Medical Technology 细胞生物学 Cell Biology 医学 Medicine 生物学 Biology 护理麻醉学 Nurse Anesthesia 进化生物学 Evolutionary Biology 口腔外科学 Oral Surgery 海洋生物学 Marine Biology 口腔/牙科科学 Oral/Dental Sciences 微生物学 Microbiology 骨科医学 Osteopathic Medicine 分子生物学 Molecular Biology 耳科学 Otology 医学微生物学 Medical Microbiology 理疗学 Physical Therapy 口腔生物学 Oral Biology 足病医学 Podiatric Medicine 寄生物学 Parasutology 眼科学 Ophthalmology 植物生物学 Plant Physiology 预防医学 Preventive Medicine 心理生物学 Psychobiology 放射学 Radiology 放射生物学 Radiation Biology 康复咨询学 Rehabilitation Counseling 理论生物学 Theoretical Biology 康复护理学 Rehabilitation Nursing 野生生物学 Wildlife Biology 外科护理学 Surgical Nursing 环境生物学 Environmental Biology 治疗学 Therapeutics 运动生物学 Exercise Physiology 畸形学 Teratology 有机体生物学 Organismal Biology 兽医学 Veterinary Sciences 生物统计学 Biometrics 牙科卫生学 Dental Sciences 生物物理学 Biophysics 牙科科学 Dentistry 生物心理学 Biopsychology 皮肤学 Dermatology 生物统计学 Biostatistics 内分泌学 Endocrinology 生物工艺学 Biotechnology 遗传学 Genetics 生物化学 Biological Chemistry 解剖学 Anatomy 生物工程学 Biological Engineering 麻醉学 Anesthesia 生物数学 Biomathematics 临床科学 Clinical Science 生物医学科学 Biomedical Science 临床心理学 Clinical Psychology 细胞生物学和分子生物学 Celluar and Molecular Biology 精神病护理学 Psychiatric Nursing 力学专业 数学分析 Mathematical Analysis 高等代数与几何 Advanced Algebra and Geometry 常微分方程 Ordinary Differential Equation 数学物理方法 Methods in Mathematical Physics 计算方法 Numerical Methods 理论力学 Theoretical Mechanics 材料力学 Mechanics of Materials 弹性力学 Elasticity 流体力学 Fluid Mechanics 力学实验 Experiments in Solid Mechanics 机械制图 Machining Drawing 力学概论 Introduction to Mechanics 气体力学 Gas Dynamics 计算流体力学 Computational Fluid Mechanics 弹性板理论 Theory of Elastic Plates 粘性流体力学 Viscous Fluid Flow 弹性力学变分原理 Variational Principles inElasticity 有限元法 Finite Element Method 塑性力学 Introduction of Plasticity
科技英语中专业术语的 翻译 集团文件版本号：（M928-T898-M248-WU2669-I2896-DQ586-M1988）
科技英语中专业术语的翻译 1.意译：根据科技术语的含义，将其翻译成汉语里和它完全对等的名词就叫意译。对单个词语来说，意译也就是直译。意译法是最常用的翻译方法，它能使读者直接了解术语的含义。例子如下： ①firewall ．．．．．．．． ：防火墙 ②data mining ．．．．．．．．．． ：数据挖掘 ③automatic program control ．．．．．．．．．．．．．．．．．．．．．．． ：自动程序控制 2.形译：英语中有些科技术语的前半部分是表示该术语形象的字母或单词，翻译成汉语时可把这一部分翻译成表示具体形象的词，或保留原来的字母，这就叫形译。例子如下： I ．-．bar ．．． 工字钢、工字条；O ．-．ring ．．．． 环形圈；twist ．．．．．-．drill ．．．．．麻花钻；X ．-．Ray ．．．X 光；α．-．brass ．．．．． α黄铜[1] 3.音译：根据英语发音翻译成汉语里相应的词。科技英语中某些有专业名词构成的术语、单位名称、新型材料的名称等，在翻译时都可采用音译法。例子如下： gene ．．．． 基因；quark ．．．．． 夸克；Pentium ．．．．．．． 奔腾 celluloid ．．．．．．．．． 赛璐璐；nylon ．．．．． 尼龙 Hertz ．．．．．（Hz ）赫兹（频率单位）；lumen ．．．．．流明（光通量单位） 4.缩写词：英语首字母缩写词在科技新词中占很大比重，这类词如果译成汉语，就显得拖沓冗长，因此很多情况下干脆不翻译。例子如下： CPU ．．．：．C ．entral Processing Unit ．．．．．．．．．．．．．．．．．．．．(中央处理器) ASCII ．．．．．：．American S ．．．．．．．．．tandard ．．．．．．． C ．ode ．．． for ．．． I ．nformation ．．．．．．．．．． I ．nterchange ．．．．．．．．．． (美国信息交换标准码) ATM ．．．：．A ．synchronous ．．．．．．．．．．． T ．ransfer ．．．．．．． M ．ode ．．． (异步传输方式) 一些国际组织的缩写也常采用这种办法。例子如下： WTO ．．．(国际贸易组织)；UNESCO ．．．．．．(联合国教科文组织)；WHO ．．．(世界卫生组织)；IOC ．．． (国际奥委会)
四六级翻译——科技类词汇 1.科技园science and technology park 2.高新技术开发区high-tech industrial zones 3.信息产业IT (Information Technology) 4.电器设备electrical appliance 5.电子设备electronic device 6.电子商务e-commerce 7.人工智能artificial intelligience 8.先进技术advanced technology 9.尖端技术state-of-the-art technology 10.载人航天飞行manned space flight 11.发射成功successful launch 12.自然科学natural science 13.新兴学科new branch of science 14.科技成果research achievements 15.科学发展观concept of scientific development 16.科教兴国revitalize China through science and education 17.可持续发展战略strategy of sustainable development 18.科技基础设施science and technology infrastructure 19.专利，专利权patent 20.生态农业environmental-friendly agriculture 21.物种起源origin of species 22.生物工程bio-technology 23.基因工程genetic engineering 24.转基因食品GM food (genetically modified food) 25.技术产权technology property right 26.科技含量technology content 27.电脑病毒computer virus 28.黑客hacker 29.垃圾邮件junk mail 30.数码科技digital technology 31.虚拟社区virtual community 32.网络空间cyber space 网络文化cyber culture 33.网民netizen 34.克隆cloning 激光laser 35.纳米nanometer 粒子particle 36.太阳能/ 核能/ 原子能solar/ nuclear/ atomic energy 37.突飞猛进advance by leaps and bounds 38.技术创新technological innovation 39.中国科学院the Chinese Academy of Science 40.科学技术是第一生产力Science and technology constitute the foremost productive forces. 41.科技前沿the forefront of science and technology 42.科技发明的传播和交流dissemination and exchanges of advanced scientific and technological inventions
基本电路 包括电路模型的元素被称为理想的电路元件。一个理想的电路元件是一个实际的电气元件的数学模型，就像一个电池或一个灯泡。重要的是为理想电路元件在电路模型用来表示实际的电气元件的行为可接受程度的准确性。电路分析，本单位的重点，这些工具，然后应用电路。电路分析基础上的数学方法，是用来预测行为的电路模型和其理想的电路元件。一个所期望的行为之间的比较，从设计规范，和预测的行为，形成电路分析，可能会导致电路模型的改进和理想的电路元件。一旦期望和预测的行为是一致的，可以构建物理原型。 物理原型是一个实际的电气系统，修建从实际电器元件。测量技术是用来确定实际的物理系统，定量的行为。实际的行为相比，从设计规范的行为，从电路分析预测的行为。比较可能会导致在物理样机，电路模型，或两者的改进。最终，这个反复的过程，模型，组件和系统的不断完善，可能会产生较准确地符合设计规范的设计，从而满足需要。 从这样的描述，它是明确的，在设计过程中，电路分析中起着一个非常重要的作用。由于电路分析应用电路模型，执业的工程师尝试使用成熟的电路模型，使设计满足在第一次迭代的设计规范。在这个单元，我们使用20至100年已测试通过机型，你可以认为他们是成熟的。能力模型与实际电力系统理想的电路元件，使电路理论的工程师非常有用的。 说理想电路元件的互连可用于定量预测系统的行为，意味着我们可以用数学方程描述的互连。对于数学方程是有用的，我们必须写他们在衡量的数量方面。在电路的情况下，这些数量是电压和电流。电路分析的研究，包括了解其电压和电流和理解上的电压施加的限制，目前互连的理想元素的每一个理想的电路元件的行为电路分析基础上的电压和电流的变量。电压是每单位电荷，电荷分离所造成的断电和SI单位伏V = DW / DQ。电流是电荷的流动速度和具有的安培SI单位（I= DQ/ DT）。理想的基本电路元件是两个终端组成部分，不能细分，也可以在其终端电压和电流的数学描述。被动签署公约涉及元素，当电流通过元素的参考方向是整个元素的参考电压降的方向端子的电压和电流的表达式使用一个积极的迹象。 功率是单位时间内的能量和平等的端电压和电流的乘积;瓦SI单位。权力的代数符号解释如下： 如果P> 0，电源被传递到电路或电路元件。 如果p<0，权力正在从电路或电路元件中提取。 在这一章中介绍的电路元素是电压源，电流源和电阻器。理想电压源保持一个规定的电压，不论当前的设备。理想电流源保持规定的电流不管了整个设备的电压。电压和电流源是独立的，也就是说，不是任何其他电路的电流或电压的影响;或依赖，就是由一些电路中的电流或电压。一个电阻制约了它的电压和电流成正比彼此。有关的比例常数电压和一个电阻值称为其电阻和欧姆测量。 欧姆定律建立相称的电压和电流的电阻。具体来说，V = IR电阻的电流流动，如果在它两端的电压下降，或V=_IR方向，如果在该电阻的电流流是在它两端的电压上升方向。 通过结合对权力的方程，P = VI，欧姆定律，我们可以判断一个电阻吸收的功率：P = I2R= U2/ R 电路节点和封闭路径。节点是一个点，两个或两个以上的电路元件加入。当只有两个元素连接，形成一个节点，他们表示将在系列。一个闭合的路径是通过连接元件追溯到一个循环，起点和终点在同一节点，只有一次每遇到中间节点。 电路是说，要解决时，两端的电压，并在每个元素的电流已经确定。欧姆定律是一个重要的方程，得出这样的解决方案。 在简单的电路结构，欧姆定律是足以解决两端的电压，目前在每一个元素。然而，对于更复杂的互连，我们需要使用两个更为重要的代数关系，被称为基尔霍夫定律，来解决所有的电压和电流。 基尔霍夫电流定律是： 在电路中的任何一个节点电流的代数和等于零。 基尔霍夫电压定律是： 电路中的任何封闭路径上的电压的代数和等于零。 1.2电路分析技术 到目前为止，我们已经分析应用结合欧姆定律基尔霍夫定律电阻电路相对简单。所有的电路，我们可以使用这种方法，但因为他们而变得结构更为复杂，涉及到越来越多的元素，这种直接的方法很快成为累赘。在这一课中，我们介绍两个电路分析的强大的技术援助：在复杂的电路结构的分析节点电压的方法，并网电流的方
翻译是把一种语言里已经表达出来的事物用另一种语言准确流畅地进行重新表达的过程。与其他题材的文章相比,科技专业文章在内容、表达形式和风格上有很大的差别,具有科技性强、专业性强、逻辑严密、表达要求简练的特点,在翻译上力求准确全面、严谨明确和通顺简练。 1科技英语翻译遵循的基本原则 从科技文章的特点来看,大多具有以下几个特征:述说事理、逻辑性强、结构严密、术语繁多,语言严谨、数据精确。这就要求译文必须概念清楚、条理分明、逻辑正确、数据无误,尤其对定义、定律、公式、图表、结论等更应特别注意。科技英语作为特殊英语的一个分支,在词汇构成、遣词造句等方面都有其自身的特点,其语法结构不十分严密、语言习惯和汉语也有不少差别、词汇量大、词语繁多,因此科技英语翻译起来比较困难。另外,科技文章比较重视叙事逻辑上的连贯及表达上的明晰与畅达; 避免行文晦涩,避免表露个人感情,避免论证上的主观随意性。因此,科技英语翻译力求少用或不用描述性形容词以及具有抒情作用的副词、感叹词及疑问词,而是大量使用科技词汇、专业技术用语,译者应尊重客观事实,不能随意改动数据、回避不易翻译的文字,更不能加进自己的主观想象,进行自由翻译。 我国著名翻译家严复提出的“信、达、雅”三准则一直为不少翻译工作者所接受。 “信”指的是译文要忠实于原文,“达”是指译文的通顺达意,“雅”指的是译文的用词修辞。三准则体现了译文和原文信息等值这一基本要领。 “信、达、雅”的翻译准则对各种英语文体的翻译实践都具有指导意义,是衡量一篇译文好坏的标准,也同样适用于科技文献的翻译。由于科技文章特有的文体特征,与其他类文章相比,其“达”和“雅”的内涵不同,它要求在准确传达信息的基础上,使译文更加简洁明快,流畅通顺。2科技英语翻译的基本方法
大学各专业名称英文翻译理科SCIENCE 理科SCIENCE 课程中文名称课程英文名称 矩阵分析Matrix Analysis 面向对象程序设计方法Desig n Methods of Object orie nted Program 李代数Lie Algebra 代数图论Algebraic Graph Theory 代数几何（I ）Algebraic Geometry （I） 泛函分析Functional Analysis 论文选读Study on Selected Papers Hoof 代数Hoof Algebra 基础代数Fundamental Algebra 交换代数Commutative Algebra 代数几何Algebraic Geometry \ /
Hoof 代数与代数群量子群Hoof Algebra , Algebraic Group and Qua numb G roup 量子群表示Representation of Quantum Groups 网络算法与复杂性Network Algorithms and Complexity 组合数学Combinatorial Mathematics 代数学Algebra 半群理论Semigroup Theory 计算机图形学Computer Graphics 图的对称性Graph Symmetry 代数拓扑Algebraic Topology 代数几何(II ) Algebraic Geometry (II ) 微分几何Differential Geometry 多复变函数Analytic Functions of Several Complex Varian les 代数曲面Algebraic Surfaces 高维代数簇Algebraic Varieties of Higher Dimension 数理方程Mathematics and Physical Equation
分1. There can be no doubt the 1900s is remembered as the electronic century. A. which B. that C. what 2. Electrons, as one knows, are minute charge of electricity. A. negative B. positive C. reverse 3. A resistor is an electrical component that the flow of electrical current. A. increases B. changes C. resists 4. Frequency is the reciprocal of the period, if the period is 4ms, then the frequency would be . A. 4m/s B. C. 25Hz 5. The sixth power of two is . A. 12 B. 36 C. 64 6. A capacitor will block current, but appears to pass current by charging and discharging. A. DC …IC B. AC …DC C.
DC …. AC 7. For a 4-band resistor with “color code ”, the first band is the values. A. hundreds B. tens C. ten 8. An electronic device often used for amplifying voltage and current is _____________. A. transistor B. conductor C. diode 9. In a diode, current flows in ________ direction across the junction. A. only one B. two C. three 10. A __________ amplifier provides signal amplification with little or no distortion, so that the output is proportional to the input. A. nonlinear B. linear C. 1.电压有效值（ ） 2. 微处理器（ ） 3.电子元件（ ） 4.公共端插孔（ ） 5.外阻（ ） 6.放大器（ ） 7.脉冲直流（ ） 8.电压源（ ） 9.系统设计（ ） 10.逻辑运 算（ ） （1）internal resistance （2） pulsating DC （3）voltage sources （4）logic circuits （5）RMS voltage （6）logic operation （7）external resistance （8）number systems （9）Microprocessor （10）amplifier （11）common jack （12）digital logic circuits （13）system design （14）anode of diode （15）electrical 三、短语翻译（每小题 2 分，共 20 分） 1. Passive electrical circuits 2. Assembler language 3. The address bus 4. Analog multimeter 5. Semiconductor material 6. chip holders 7. peak-to-peak voltage 8. dual-trace oscilloscope 9. Flowchart 10. Signal generator 四、句子翻译（每小题 5 分，共 201. The impact of digital integrated circuits on our modern society has been pervasive. Without them, the