西电科技英语课后题答案

1、1矮米特博士2001年毕业于哈佛大学Dr. Emmet graduated from Harvard University in 20012李教授1988年在西安理工大学获得机械工程博士学位Professor Li earned his Ph.D. degree in mechanical engineering from the Xian University of Technology in 1988.3现在我们转向讨论一下局与网Now we shall turn to the discussion of local area networks.4 BAINBRIDGE质谱仪是与光谱仪一样

2、重要的仪器The Bainbridge mass spectrometer is as important an instrument as the optical spectrometer.5做这个实验需要多长时间How long a time 或How much time is required to this experiment?6压力的增加总会引起体积的减少。An increase in pressure always causes a decrease in volume7图2-5画出了式2-2所表示的情况。Fig. (2-5) shows what is expressed by

3、 Eq. (2-2).8电感的单位是亨利The unit of inductance is the henry.9该电路由一个电池。一个电感和一个电容器组成This circuit consists of a battery, an inductor and a capacitor.10试计算在A B C三点处的电场。Compute the electric fields at points a, b, and c.11这颗卫星用于美国与英国 法国 意大利之间的通信This satellite is used for communications between the United Stat

4、es and Great Britain, France and Italy.12我们假设该天线是垂直的 其损耗为零We assume that the antenna is vertical and that its loss is zero.13第6 7 8章论述传输线Chapters 6, 7, and 8 deal with transmission lines.14其误差为千亿分之六Its error is six parts in 1012.15这台计算机所储存的信息比那台多2倍。This computer stores four times more information th

5、an that one (does).16不久的将来对这种设备的需求量为现在的20倍The demand for this kind of equipment in the near future will be 20 times what it is.17这个元件上的电压为零点几伏特The voltage across this component is a few tenths of a volt.18现在其内部的压力减少了15倍Now its internal pressure is one sixteenth what it was.19这种新型计算机与普通计算机相比有许多优势This

6、 new type of computer has many advantages over the general type20解这个微分方程把未知量求出来并不困难It is not difficult to solve this differential equation for the unknown quantity.21在这新的五章中，第一章论述负反馈的基本原理Of these five new chapters, the first one deals with the basic principles of negative feedback.22这时 电流与电压相位相差90度A

7、t this point/time, current differs in phase from voltage by 90o.23通过分析该仪器的参数 我们就能够了解它的性能By analyzing By the analysis of the parameters of the instrument, we can understand its performance.24我们要求它在这一距离上的平均速度We will find out its average velocity over this distance.25电子学这门科学在现今世界太重要了The science of elec

8、tronics is too important in the world today. 26他们极为困难地解出了这道题They solved this problem with great difficulty.27若X1 则方程成立 For x1, there is no solution to this equation。28在把这些数值代入该方程后 我们得到了下面的表达式Upon On substituting substitution of these values into in theequation, we obtained the following expression.2

9、9这个电路的工作情况类似于图1-10的电路This circuit is similar in operation to that of Fig. 1-10.30这台计算机的性能很好This computer is very good in performance.31这些波只向一个方向传播These waves travel only in one direction.32该力垂直于桌面作用The force acts perpendicular to the surface of the table.33这里的三个系数有待于确定The three coefficients here rem

10、ains to be determined.34下面两个式子在后面几章将会经常用到 The two equations below will be often (frequently) used in later chapters/in the chapters which follow.35这里我们使用相距10厘米的两个金属球Here we use two metal balls 10 cm apart.326输出保持不变The output remains/stays constant/unchanged/fixed/unaltered/the same.37现在的教科书均讨论了这个问题A

11、ll the textbooks available discuss this problem.38计算机由于运算 速度快而得到了广泛的应用Accurate in operation and high in speed, computers have found wide applications.39这个题的答案看起来是正确的The answer to this problem looks correct.40我们将使用一段相距距离为 的两根平行导线Two parallel wires a distance (of)apart carry the current i.41现在的问题是如何测量

12、元件上的电压The problem now is how to measure the voltage across this component.42这些数据将被传送到2千米外的计算机中心These data will be sent to the computing center 2 kilometers away.43在对上面的那个方程整理后 我们得到了下面的表达式Urearranging the equation above, we have get, obtain the following expressionpon.44这些电荷能与存在的其他电荷相互作用These charges

13、 can interact with other charges present.45力可以没有接触而被传递 这与普通的观念相反Forces can be transmitted without contact, contrary to the common belief.46这个系数的典型值为0。35This coefficient is typically 0.35.47这个方程我们应该可以用以下两种方法的任何一种来解This equation can be solved in either of the following two ways/the two ways which foll

14、ow.48这个棒球不久会停下来 是因为它与地面相互作用的缘故This baseball will soon come to rest because of its interaction with the ground.49我们把这个系数选为1是正确的Our choice of this coefficient as 1 is correct.50从把它定义为力与长度之比 我们可以看出K具有与功相同的单位Frof a force to a length, we can see that k has the same unit as work om its definition as the r

15、atio 51我们对该机器的分析很有意义Our choice of this coefficient as 1 is correct.52这有助于把他们用在电路分析中This facilitates their use in circuit analysis.53这辆警车装备了像火柴盒那样大的接收机This police car is equipped with a receiver the size of a matchbox. 54人们使用一根丝线的百分之一那样粗细的导线来连接这些部件Wires one hundredth the diameter of a silk thread are

16、 used to connect these components.55我们必须对这些设备进行水冷却We must water cool these equipments/devices.56在过去 电话是靠接线员来连接的In the past, telephone calls were operator connected.57交流电可以被转换成直流电 这一过程被称为整流AC can be changed/turned/converted/transformed/translated into/to DC, a process called/known as/referred to as r

17、ectification.58磁铁能够吸引铁制材料，这是大家熟悉的现象A magnet attracts iron materials, a familiar phenomenon.59计算机能够处理信息 而这一过程以前只能在我们的头脑里完成Computers are capable of processing information, a process that previously could be accomplished only inside our heads.60万里表是测量电流 电压 电阻的仪表 它广泛应用在电气工程中An instrument for measuring c

18、urrent, voltage, and resistance, the multimeter is widely used in electrical engineering.61第1.1和1.2节将讨论其他几个问题Secs. 1.1 and 1.2 will discuss several other problems.62习题列在第1到5页上Problems are listed/given on pp. 1-5.63在上面的几个式子中 所有的H都是混合参数In the equations above, all hs are the hybrid parameters64标准磅的质量等于

19、 千克The mass of the standard pound is equal to 0. kilograms.65式5-1中的所有A和B都是与阻抗R有关All as and bs in Eq. (5-1) are related to the impedance Ro66我们必须把温度对半导体的影响考虑进去We must take the effect of temperature on upon semiconductors intoaccount.67在这个情况下 输出随输入的变化是很小的In this case, the variation of output with inpu

20、t is very small.68这一曲线表示出了距离对于速度的依从关系This curve shows the dependence of distance on/upon speed. 69人们将会注意到 这个像是个实像This image, it will be noticed, is a real image.70我们希望 这个技术问题不久就会解决的This technical problem, we hope, will be solved soon.71 2近似为1000 这一点我们认为在学习数字电子学中是很有用的210 is approximately 1000, a fact

21、 that we think is very useful in the study of digital electronics.72这里应该使用一下比如说100欧姆的电阻器A resistor of say 100 ohms should be used here.73那些教科书均没有提到着一点None of those textbooks have/has mentioned this point.74这些X值并非都能满意该方程All of these x values cannot satisfy the equation.75那两个条件在此均没有得到满足Neither of the

22、two conditions is satisfied here.76在前一章我们讨论了能量In the preceding/previous chapter, we discussed all kinds of force.77本文讨论了设计飞机的一种新方法This paper describes a new method for designing aircraft.78到上个世纪末 该公司已制造了五千部雷达By the end of the last century, the company had manufactured 5 000radars.79自从2008年以来 这个研究所一直

23、在开发一种特殊的机器人Since 2008, this research institute has been developing a special kind of robot80在1 2节介绍了力的概念In Section 1-2, the concept of force was introduced.81早在20世纪40年代 人们发现半导体是很有用的As early as the 1940s, it was found that semiconductors are very useful. 82这一结果也能够用另一种方法来获得This result can also be arri

24、ved at in another way.83当时人们没有使用那一现象At that time no use was made of this phenomenon/, thisphenomenon was made no use of.84这一点将在下一章讨论This point will be dealt with in the next section.85这台计算机的性能比那台好多了 This computer works much better than that one (does)/This computer is much better in performance than

25、 that one 86这台计算机所需的元件数比那台多的多This computer requires many more components that that one 87月亮离地球的距离远达24万英里The distance of the moon from the earth is as great as 240 000 miles.88电阻越大 电容器达到其最大电压所需时间越长The greater the resistance, the longer time it takes for the capacitor to reach its maximum voltage89小达0

26、.1A的电流不能产生足够的热The current as small as 0.1 A cannot produce enough heat.90借助于计算机设计这种飞机只需要几个月的时间It will take a few months to design this kind of aircraft with the help of a computer.91证明这个表达式成立就留作读者的一个习题It is left as a problem to for the reader to show that this expression holds.92要执行的程序储存在这一单元中The pr

27、ogram to be executed is stored in this unit.93这山谷用作为建坝的基础上This valley acts as the foundation on which to build the dam.94这实验中有许多仪表供学生选择In this laboratory there are many kinds of instrument for students to choose from.95设t等于零Let t0 equal/be equal to zero.96目标离得越远 回波返回所需的时间越长The farther away the targe

28、t (is), the longer time it takes for the echo to return.97为使该级数收敛 X必须小于1For the series to converge, x must be less than 1.98我们发现这个概念很难理解We find this concept very difficult to understand.99这个方法使得检测目标容易得多This method makes it much easier to detect targets.100这个因素会影响计算机存储信息的能力This factor will affect the

29、 ability of a computer to store information.101我们得求出使r为多大时才能使该级数收敛We have to find out how large to make r so as for the series to converge.102这是画画所用的笔This is a pen to draw pictures with.103弹性是物体形变后恢复原形的趋势Elasticity is the tendency of a body to return to its original condition after being deformed.10

30、4普通物质被说成是电中性的Ordinary matter is said to be electrically neutral.105这一性质使得金属能够被作成任何的形状This property makes it possible for metals to be made into any shape.106这张桌子不适宜学生做实验This table is unfit for a student to do experiments on.107现在我们考虑取什么样的积分路径Now we consider what path of integration to take.108该放大器放大

31、接收到的信号The amplifier amplifies the received signals.109运动的分子具有动能Moving molecules have kinetic energy.110速度等于距离除以时间Speed equals distance divided by time.111电压等于电流乘以电阻Voltage equals/is equal to current multiplied by resistance.112空气阻力随速度的增加而增加The resistance of air increases with the increased/increasin

32、g/an increase in speed.113变压器是由饶在铁心上的两个或多个线圈组成的一种装置A transformer is a device consisting of two or more coils wound on/round an iron core.114必须求出流过这个元件上的电流It is necessary to find out the current flowing through this component.115这本书 如果使用得当 对读者是很有帮助的This book, properly used, will be of great help to t

33、he reader.116流过电路的时候 电流会失去一部分能量Flowing through a circuit, the current will lose part of its energy.117若已知时间和速度 我们就能求出距离来Given/Knowing time and speed, we/one can find out distance.118学完这章后 学生们将懂得计算机原理了Having studied this chapter, the student will understand/will have understood the principle of a com

34、puter.119由于光速极大 我们不能用普通的方法来测量它The speed of light being extremely great, we cannot measure it by ordinary methods.120在过去发射了几颗通信卫星 他们都是高空卫星Several comsats were launched, all of them (being) high-altitude satellites.121因特网被称为所有网络之母 它是使用极为广泛的国际网络Called “the mother of all networks,” the Internet is a wid

35、ely used international network.121这个力可以分解成两个分量 一个是水平的一个是垂直的This force can be resolved into two components, one (being) horizontal and the other vertical.122让我们以原点为圆心作为半径为r的圆Let us construct/draw a circle with the origin as the center and of radius R.123这个参数应该在E接地的情况下加以测量This parameter should be meas

36、ured with E grounded.124若电路中没有电阻 电流就会无限增大With no resistance in the circuit, the current will increase indefinitely.125由于考虑到这一点 我们编写了这本书With this in view, we have written this book.126本文介绍了一种新的设计方法 重点放在其原理上This paper introduces a new design method/technique, with emphasis on its principle.127让我们来考虑设计

37、一台计算机Let us consider designing a computer.128我们把这些元件称为是无源的We refer to these components as being passive.129这涉及到取傅式变换This involves taking the Fourier transform.130对上面的方程整理后 我们得到了以下一个方程组On/Upon rearranging the above equations, we obtain the following set of equations.131在使用这个式子时 把哪一个平面看成1是没有关系的In usin

38、g this equation, it does not matter which plane is considered as 1.132直到引入了一种完全不同的概念 这个问题才得到了解决The problem was not solved until a completely different method was introduced.133在过了将近一百年之后才由实验证实了亚原子微粒的存在Nearly 100 years passed before the existence/presence of subatomic particles was confirmed by exper

39、iment/experimentally.134在发明该设备的那年 爆发了第二世界大战The year this device was invented, World War II broke out.135虽然原子很小 它们是由更小的微粒构成的Small as they are, atoms are made up of still smaller particles.136这两个电阻应该选择得使该晶体管能正常工作These two resistors should be selected/chosen so that the transistor can operate normally.

40、137该物体处于这样的状态以至于它能做功The body is in such a state that it can do work.138电压是电流和电阻之乘积这一关系适用于一切直流电路The relation that voltage is the product of current and resistance applies to all the dc circuits139磁能够产生电流这一发现在电学领域中是极为重要的The discovery that magnetism can produce current is extremely important in the fie

41、ld of electricity.140方程式就是两个代数式相等的一种代数陈述An equation is an algebraic statement that two algebraic expressions are equal.141有证据表明 月球上没有生命存在There is evidence that no life exists on the moon.142现在出现了这么个问题 该算法是否实用呢？The question now arises whether the algorithm is of practical use.143在这种情况下 不能保证该级数是收敛的In

42、this case there is no guarantee that the series is convergent144人们越来越认识到这些方法是很有用的There is a growing/increasing awareness that these techniques/methods are very useful145当时最显著的成就之一是人们认识到了光是由电磁波组成的One of/Among the most noteworthy achievements at that time was the realization that light consists of ele

43、ctromagnetic waves.146这是由于导体中存在有许多自由电子引起的This is due to/is caused by/results from the fact that there are many free electrons in conductors.147除了材料的性质应该包括在分析模型之中外 我们还必须把其他因素考虑进去Besides/In addition to the fact that the properties of the material should be included in the analytical model, we must tak

44、e other factors into account.148现在有待于确定该级数何时收敛Now it remains to be determined when the series converges.149从杜巴梅尔定理可清楚地看出 这个极限是存在的It is clear from Dubamels Theorem that this limit exists.150由麦克斯韦假设得知 每当电场发生变化时就产生出磁场It follows from Maxwells hypothesis that whenever there is a change in an electric fie

45、ld, a magnetic field is produced.151在这种情况下磁铁是否被运动是没有关系的It does not matter whether the magnet is moved in this case.152温度确定了热传递将朝哪个方向发生Temperature determines in what direction the transfer of heat will take place.153一切物质均是由微粒构成的 这现在已是一个众所周知的事实了It is now a well-known fact that all matter consists of t

46、iny particles.154发电机所做的是把机械能转变成电能What a generator does is (to) change mechanical energy into electrical energy.155这一章所讲的内容非常重要What this chapter describes/What is described in this chapter is of great importance.156物质是能够占有空间的东西Matter is what can occupy space.157在这个实验中我们所发现的是电现象这一崭新领域What we have disc

47、overed in this experiment is the entirely new realm of electrical phenomenon.158这个方向与假设方向相反This direction is opposite to what has been assumed.159大小 方向和作用点就是我们所说的一个力的三要素Magnitude, direction, and place of application are what we call the three elements of a force.160这些数构成了所谓的实数系These numbers constitu

48、te what is known as the real number system.161在下面 我们要熟悉一些基本概念In what follows, we shall acquaint ourselves with some basic concepts.162我们用来测量一个电阻上电压的仪表被称为电压表The meter (that/which) we use to measure the voltage across a resistor is called a voltmeter.163计算机是人类所曾拥有过的最有效的助手Computers are the most efficie

49、nt assistants (that) man has ever had.164现在这种病不再是原来那样的严重问题了Now this disease is no longer the serious problem (that) it once was.165雷达可以测出无线电回波返回的时间Radar can measure the time (that) it takes for the radio echo to return.166我们必须计算出该物体被提到的距离We must calculate the distance (that/through which) the body i

50、s lifted.167一个物体运动的方向也是很重要的he direction (that/in which) a body moves is also very important.168这个质点每秒钟震动的次数被叫做频率The number of times (that/by which) this particle vibrates per/a second is called/termed/named/known as/spoken of as/referred to as frequency.169我们使这两个比值相等 由此得到了最简式We equate these two rati

51、os, from which the simplest formula follows/results.170需要确定Y分量降为0的时间It is necessary to determine the time when/that/at which the y-component has decreased to zero.171其每一点的Y坐标均为0的曲线就是X轴The curve the y-coordinate of each point on which is zero is just the x-axis.172该圆切割实轴的点处于A=W处The point at which the

52、 circle cuts the axis of reals is where = .173重力的意思是地球吸引物体的力The force of gravity means the force with which the earth attracts a body.174电子在其上面产生图像的显像管的表明称为荧光屏The surface of a picture tube upon which the electrons produce the picture is called the screen.175作者要感谢本书所属的那套丛书的编辑们The author would like to express thanks to the editors of the series of which this book is a part/to which this book belongs.176这是给定的两个矢量为其边的一个平行四边形This is a parallel