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V、练习参考答案

练习

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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μ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。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] length of the wire. 5. The density of a substance is its mass per unit volume. 6. The radius of the earth is 6.37×106 m. 7. The [These] two parameters are the same. 1 / 43

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 inductance 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 following 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 other 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. 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 unique 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-transition 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. 2 / 43

7. We propose a numerical method based on Newton’s iterative method.

练习II、

1. Ordinary transformers are not ideal, and therefore power 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 Britain, France and Italy. 6. Matter is anything like air, water or wood. 7. Assume that losses in the coil are zero, that C = 500μF, 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 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 important 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 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、

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2

The concept of temperature 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 the 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 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 convex, and that the Hessian determinant is positive.

练习

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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 [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 parameters 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. 4 / 43

12. This paper introduces a new method for measuring 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. 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 earth’s rotation.

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 negative 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 new 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 launched on the morning of the 8th of October. 6. Voltage is measured in volts. 7. This experiment started at 8 o’clock last night. 8. They will leave for Beijing to attend an international conference on mobile communication.

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