秦荻辉科技英语写作教程练习答案全部版.doc

1、V、 练习参考答案 练习 1 II、 1、 an（人们对这课题的兴趣越来越浓。 ) 2、 a （功率额定值是电阻器不会引起温度太大的上升而能安全地耗散的最大功率。） 3、 an（其主要的缺点是增加了噪声。） 4、 The; a（该设备的成功设计需要详细地了解性能指标。） 5、 the; a; a（在氢原子的布尔模型中，一个电子绕一个质子以半径为 R的圆周运转。） 6、 the（ 频率的单位是赫兹。） 7、 a; a; an; the（如果在电路的 两端加上电压的话，就会有电流在电路中流动。） 8、 /; /（图 5 1 画出了 Oersted 的实验。） 9、 an（这里我们应该使用一个 18

2、 伏的电池。） 10、 A; a; a（机器是能够传递力来完成某一确定目的的一种设备。） 11、 The; /（水压机将在第 14 章加以考虑。） 12、 The; the; the（研究处于运动中的流体，是力学中较为困难的分支之一，因为可能出现的现象是多种多样的。） 13、 the; the /（我们容易确定参数 的值。） 14、 /; the（根据式（ 2 1），我们得到以下的关系式。） 15、 an（在这里必须使用一根 S 形管子。） 16、 the; /（作者工作在位于阿林顿的得克萨斯大学。） 17、 an（这是一只 R 位的变换器。） 18、 An（这里必须使用一个 “异”或 门电路

3、。 XOR = Exclusive OR） III、 1. This is an h parameter. 2. We turn now to a discussion of local area networks. 3. The Bainbridge mass spectrometer is as important an instrument as the optical spectrometer. 4. It is necessary to find out how long a time is required for an electron to travel the this le

4、ngth of the wire. 5. The density of a substance is its mass per unit volume. 6. The radius of the earth is 6.37106 m. 7. The These two parameters are the same. 8. An increase in pressure always causes a decrease in volume. 9. Fig. (2-5) shows what is expressed by Eq. (2-2). 10. The unit of inductanc

5、e is the henry. 11. Too large an input signal can cause nonlinear distortion. 12. Using the definition of slope, we can derive the equation which represents a straight line. 13. The expression f (x h) f (x) is frequently used in the study of calculus. 14. An equation which can be written in the foll

6、owing form is known as a linear equation in one unknown. 15. In a computer, the tendency is to operate at as high a clock rate as possible. 16. Tin does not have as high a melting point as lead (does). 17. This average velocity is half the final velocity. 18. Electricity can be easily changed into o

7、ther forms of energy. 19. In 1831, Joseph Henry in the United States discovered the phenomenon of electromagnetic induction. 20. A computer consists of several parts units. IV、 Chemistry is based upon concepts that require the measurement of such quantities as length, volume, mass, and temperature.

8、These measurements are quantitative; that is, they have numbers associated with them. In this section, we will consider some of the simple instruments used in quantitative measurements. We will also look at the units used to express these measured quantities. V、 1. The UASMA protocol employs a uniqu

9、e frame structure. 2. Performance analysis of an M-ary spread spectrum receiver using biorthogonal cyclic codes 3. Finally, a broad stepped impedance transformer is designed by this method. 4. Dynamic analysis and evaluation of the security of a proactive secret sharing system 5. With the state-tran

10、sition diagram, the security probability of the system is obtained. 6. The approach can be applied to the one-dimensional potential barrier with an arbitrary profile. 7. We propose a numerical method based on Newtons iterative method. 练习 2 II、 1. Ordinary transformers are not ideal, and therefore po

11、wer losses occur in them. 2. This material attracts iron objects and can even magnetize them. 3. This circuit consists of a battery, an inductor and a capacitor. 4. Compute the electric fields at points a, b, and c. 5. This satellite is used for communications between the United States and Great Bri

12、tain, France and Italy. 6. Matter is anything like air, water or wood. 7. Assume that losses in the coil are zero, that C = 500 F, and that the ripple is 20 percent. 8. It is found more convenient to adopt the point of view that a moving charge sets up a magnetic field, and that this field exerts a

13、force on another charge moving through it. 9. Chapters 6, 7, and 8 deal with what is called the electronic brain. 10. Students may learn that mathematics is the language for scientific ideas, that science is a source of mathematical ideas, and that mathematics can furnish brilliant answers to import

14、ant scientific problems. III、 1. The current in the circuit is one half the short-circuit current of the source. 2. The internal resistance of this kind of storage battery is only a few thousandths of an ohm. 3. Its error is six parts in 1012. 4. This computer stores four times more information than

15、 that one (does). 5. The mass of the moon is 1/80 that of the earth. 6. The demand for this kind of equipment in the near future will be 20 times what it is. 7. The voltage across this component is a few tenths of a volt. 8. Now its internal pressure is one third what it was. IV、 The concept of temp

16、erature is familiar to all of us. This is because our bodies are so sensitive to temperature differences. When we pick up a piece of ice, we feel cold because its temperature is lower than that of our hand. After drinking a cup of coffee, we may refer to it as “hot,” “lukewarm,” or “atrocious.” In t

17、he first two cases, at least, we are describing the extent to which its temperature exceeds ours. V、 1. The voltage across this capacitor is a few hundredths of a volt. 2. This object is five times heavier than that one is. 3. Unless otherwise stated, it is assumed that silicon transistors are used

18、and that ICBO can be neglected. 4. This circuit has the advantages of simple structure and easy adjustment. 5. Figs. 1, 2, and 3 show this process. 6. For further information, consult references 3, 5, 9. 7. The interior point is a minimum rather than a maximum, given that the return functions are co

19、nvex, and that the Hessian determinant is positive. 练习 3 II、 1. This type of computer has many advantages over that type. 2. We must solve this equation for the loop current. 3. Of these five new chapters, the first one deals with the basic principles of negative feedback. 4. This section introduces

20、 presents the concept of force. 5. This parameter varies changes with temperature. 6. The current and voltage in this circuit differ in phase by 90o. The phases of the current and voltage in this circuit differ by 90o. 7. Sound waves travel in all directions. 8. By analyzing By the analysis of the p

21、arameters of the instrument, we can understand its performance. 9. This is a sufficient and necessary condition for solving the solution of the equation. 10. We will find out its average velocity over this distance. 11. We measure force in newtons. 12. This paper introduces a new method for measurin

22、g this parameter. III、 1. For x 1, there is no solution to this equation this equation has no solution. 2. Upon On substituting substitution of these values into to the equation, it was found that v is equal to the velocity of light. 3. In their study of electricity, physicists defined the parameter

23、. 4. This circuit is similar in operation to that of Fig. 1-10. 5. In our discussion of this subject, we shall restrict our attention to its basic principles. 6. We describe the interactions among charges with the help of the concept of electric field. 7. This is due in part to the earths rotation.

24、8. Upon On application of proper external force, the body will start to move. 9. This computer is very small in size. 10. These waves travel only in one direction. IV、 The common dry cell used in flashlights is constructed as shown in Fig. 2-28. The positive electrode is a carbon rod and the negativ

25、e one is a zinc can. The cell is called “dry” because its electrolyte is a moist paste. If it were actually dry, ions in the electrolyte could not move about and no current could be produced. In the operation of the cell, zinc atoms become zinc ions by losing electrons. V、 1. This paper presents a n

26、ew method for the recognition of radar targets. 2. The influence of the moving state of the target on the tracking accuracy of the EKF is great. 3. This new method has many advantages over those available. 4. This newly designed instrument is good in quality is of good quality. 5. Another comsat was

27、 launched on the morning of the 8th of October. 6. Voltage is measured in volts. 7. This experiment started at 8 oclock last night. 8. They will leave for Beijing to attend an international conference on mobile communication. 练习 4 II、 1. The answer (key) to this problem looks (appears) correct. 2. T

28、his coefficient remains to be determined. 3. The two equations below will be often (frequently) used in later chapters. 4. Here we use two metal balls 10 cm apart. 5. This paper contains (has) nothing new. There is nothing new in this paper. 6. The force acts perpendicular to the surface of the tabl

29、e. 7. This rule can be used for can apply to all integers, both positive and negative. 8. A neutron has a mass slightly larger than that of a proton. has a slightly mass than a proton. 9. Electrons are the smallest particles present in ordinary matter. 10. All the textbooks available discuss this pr

30、oblem. 11. Accurate in operation and high in speed, computers have found wide applications. 12. The input goes negative and while the output stays constant. 13. These rays seem to come from the image. 14. Impedance in an ac-circuit plays the same role that resistance does in a dc-circuit. 15. Two pa

31、rallel wires a distance (of) apart carry the current i. 16. The equations here are of great importance. 17. We shall use a cable 10 meters long. 18. The problem now is how to measure the voltage across this component. 19. These data will be sent to the computing center 2 kilometers away. 20. Upon re

32、arranging the equation above, we have get, obtain the following expression. 21. That statement sounds quite reasonable. 22. Electrons can pass relatively unimpeded through metals. 23. The body collides with other bodies nearby. 24. These charges can interact with other charges present. 25. Forces ca

33、n be transmitted without contact, contrary to the common belief. 26. There is no root larger than 1 unity. 27. This coefficient is typically 0.35. 28. The charge is moving parallel to the electric field. III、 The density of a substance is the ratio of its mass to its volume. Densities of liquids and

34、 solids are most often expressed in grams per cubic centimeter. Their densities can be found by measuring, independently, the mass and volume of a sample. For With solids, density is a bit more difficult to determine. A common approach is shown in Fig. 1.4. The mass of the sample is first measured (

35、by) using with a balance. Its volume is found indirectly by determining the volume of liquid displaced by the solid. IV、 1. This running machine will stop of itself in one or two minutes in a minute or two. 2. In this case, the input does not fall; nor neither does the output. ; the output does not

36、fall, either. 3. The resistance of a conductor depends not only on the material of which the conductor is made, but also on the size and temperature of the conductor. 4. These scientists are very interested in this topic. 5. This parameter can hardly be measured. 6. The preface to this book is well

37、written. 7. In this laboratory, this instrument is more expensive than any other one. than any one else. 8. The features of this device are small size and light weight. 练习 5 II、 1. The detection process can be performed in either of the following two ways. 2. There is a capacitance across the juncti

38、on. Its presence existence will cause problems at high frequencies. 3. This baseball will soon come to rest because of its interaction with the ground. 4. Our choice of this coefficient as 1 is correct. 5. This is due to its use of relays rather than electronic devices. 6. Since transformers are lar

39、ge, heavy, and expensive, their elimination from the circuit will result in considerable savings. 7. Emphasis is put on floated gyroscopes because of their utilization use as a control component. 8. From its definition as the ratio of a force to a length, we can see that k has the same unit as work

40、(does). 9. In this equation, that factor is ignored. Its inclusion here would merely complicate the proceedings. 10. In their discussion of that problem, scientists noticed this point. 11. Since feedback plays an important role in electronic circuits, its study is of great importance. 12. The black

41、hole is invisible cannot be seen, but its presence existence can be deduced. 13. Our analysis of the machine is of great significance. 14. This facilitates their use in circuit analysis. 15. The success in design depends on our correct choice of the circuit. III、 1. Soon Before long we shall have co

42、mputers the size of a watch. 2. This police car is equipped with a receiver the size of a matchbox. 3. Wires one hundredth the diameter of a silk thread are used to connect these components. 4. We must heat treat these tools. 5. In the past, telephone calls were operator connected. 6. This device is

43、 computer controlled. 7. This device is water resistant. 8. AC can be changed turned, converted, transformed, translated into to DC, a process called known as, referred to as rectification. 9. A magnet attracts iron materials, a familiar phenomenon. 10. If this relation were to hold, we would have a

44、 negative current, an impossible situation. 11. The current in a circuit is proportional to the applied voltage, something a fact that was verified experimentally by Ohm. 12. Computers are capable of processing information, a process that previously could be accomplished only inside our heads. 13. A

45、 new technology introduced in the 1960s, laser can pierce the hardest substances such as diamond. 14. A very effective separation method, chromatography has found wide applications. 15. This aluminum bar 2.5 m long has a rectangular cross section 1 cm by 5 cm. 16. This law applies to bodies the spee

46、d of a rocket. 17. We must frequency modulate it. 18. To solve this problem, we must take everything all factors into account, a very complicated procedure. 19. An instrument for measuring current, voltage, and resistance, the multimeter is widely used in electrical engineering. 20. These materials

47、are pressure sensitive. IV、 1. In the equations above, all hs are the hybrid parameters. 2. Between times t2 and t3 the diode appears to be on. 3. In this circuit, there are three emfs. 4. The mass of the standard pound is equal to 0.4535924277 kilogram s. 5. All as and bs in Eq. (5-1) are related t

48、o the impedance Ro. 6. This section describes the advantages of AC over DC. 7. We must take the effect of temperature on upon semiconductors into account. 8. In this case, the variation of output with input is very small. 9. This curve shows the dependence of distance on upon speed. 10. The use of t

49、he atomic energy as the source of power is very important. 11. The separation of impurities from the ore is very difficult. 12. We are all familiar with the definition of current as the flow of charge. V、 Energy may be thought of as the ability to do work. When we say that something has energy, we mean that it is capable of exerting a force on something else and doing work on it. On the other hand, when we do work on something, we hav