西交2012春季专业英语离线作业及答案

西安交通大学现代远程教育考试卷 成绩 课 程:专业英语 专业班号 考试日期 年 月 日 姓 名 学号 期中 期末 一． 根据下面的英文解释，写出相应的英文词汇。（共10分，每空1分） 二. 根据电气工程专业基本知识，判断正误。（共10分，每空1分） 1. In alternating current an AC generator is used to make electrons flow continuously in one direction. __错___ 2. In North American 50Hz is adopted as standard frequency in electric power system. ___错__ 3. A computer’s microprocessor only understands high-level language. ___错__ 4. Instructions written in a high-level language must be translated into machine language in binary form before a computer can use them. _对___ 第 1 页 共 6 页 5. In alternating current an AC generator is used to make electrons flow continuously in one direction. 错_____ 6. In China alternating current is usually generated at 60Hz. __错___ 7. The north pole of the armature is attracted to the south pole of the main field. The south pole of the armature is attracted to the north pole of the main field. _对_ 8. When three capacitors connected in series, Ctotal?C1?C2?C3. _错_ 9. The commutator can change current direction in the conductor. _对_ 10. Most computers are equipped with a keyboard as the primary output device. _对_ 三. 基本词汇的英汉互译。（共15分，每题1.5分） 1. ____额定电流________ rated armature current 2. 理想电源 Ideal voltage source _ 3. _电路参数___________ circuit parameters 4. 周期电流 _ Periodic current ___________ 5. __负反馈__________ negative feedback 6. 直轴 _ Direct axis ___________ 7. 有功电流分量 _ Active component of current ___________ 8. _无功电流___________ reactive current current 9. 电网 ___ Power grid _________ 10. _数字继电器___________ digital relays 四. 根据电气工程基本知识，完成填空。（共30分，每空1分） 1. Resistors are _____ elements. A. passive B. active C. independent sources D. dependent sources 2. An electric heater draws 10 A from a 120V line. The resistance of the heater is _____. A. 1200? B. 120? C. 12? D. 1.2? 3. The algebraic sum of all voltages around a loop is _____. A. zero B. indefinite value C. sum of voltage rises D. sum of voltage drops 4. ON-OFF information can be represented by _____ signal. A. a digital B. an analog C. a discrete D. a control 第 2 页 共 6 页 5. In North American _____ is adopted as standard frequency in electric power system. A. 25Hz B. 50Hz C. 60Hz D. 125Hz 6. _____ can provide an asynchronous link between two ac electric power system with different nominal frequencies. A. The HVDC (high voltage DC) transmission B. The EHV (extra-high voltage) AC transmission C. The AC distribution D. Generators 7. The generator voltages are usually stepped up to the transmission voltage level by _____. A. series capacitor B. parallel reactors C. step-up transformers D. step-down transformers 8. A D/A is a device that can convert a digital signal to the equivalent _____. A. digital form B. numerical form C. binary form D. analog form 9. The precision of ADC ( analog-to-digital conversion ) is determined by _____. A. its speed B. its gain C. the accuracy of the reference voltage D. the number of binary bits 10. When an induction motor with 10 poles is supplied by 50Hz three-phase ac power source, the synchronous revolutions per minute is _____. (Synchronous r/min = 120 f/p) A. 1000 B. 900 C. 700 D. 600 11. A computer printer is _____ device that produces computer-generated text or graphical images on paper. A. an input B. an output C. a storage D. a data processing 12. _____ carries data out to speakers and headphones, or back from a microphone. A. A graphics card B. A modem C. A network card D. A sound card 13. A computer’s microprocessor only understands _____ in binary form. A. high-level languages B. machine language C. human languages D. assembly language 第 3 页 共 6 页 14. Delphi belongs to _____. A. low-level programming language B. high-level programming language C. a programming language connected with the computer hardware behavior D. an assembly language 15. A floppy disk drive is _____ device that reads data from and writes data to floppy disks. A. an input B. an output C. a storage D. a data processing 16. In a coal-fired power plant, an electrostatic precipitator is used to remove _____ from the combustion gases. A. solid particle B. SO2 C. CO D. water vapour 17. In cogeneration（热电联产，热电联供） systems, the overall energy efficiencies are raised by _____. A. important the combustion process B. providing thermal energy to the customers C. raising the steam temperature D. reducing SO2 emissions 18. The hydropower is well suited for switching according to _____ command to meet changing power needs. A. a consumer’s B. a user’s C. a dispatcher’s D. an operator’s 19. The total transfer function for G1?s? and G2?s?in cascade is不会_. A. G1?s? B. G2?s? C. G1?s?G2?s? D. G1?s??G2?s? 20. The system’s characteristic equation can be used to determine _____ of a linear time-invariant system. A. the stability B. magnitude of the steady-state error C. the controllability D. the observability 21. The Buck（降压式变换器） is a _____ converter. A. voltage step-up B. current step-down C. current step-up D. resistance 22. A frequency response is a function of the variable _____. A. s B. j? C. D D. t 第 4 页 共 6 页 23. The unit of logarithm of the magnitude of a transfer function is _____. A. radians per second B. volts C. decibel D. octaves 24. The DC-DC converts _____ input to _____ output. A. direct current, alternating current B. direct current, direct current C. alternating current, alternating current D. alternating current, alternating current 25. The primary winding is connected to _____. A. the power source B. the load C. the measurement instrument D. the motor 26. Copper losses are _____ losses in the primary and secondary windings of the transformer core. A. inductive B. capacitive C. resistive D. reactive 27. The relation A?A results in _____. A. null B. identity C. indefinite value D. zero 28. The notebook computers use _____ as standard display equipment. A. CRT display B. LCDs C. LED D. TV screen 29. An expansion slot is a long, narrow socket on the motherboard into which you can plug _____. A. an expansion card B. a modem C. a network card D. a sound card 30. The transformer is a straightforward application of Faraday’s ______ Law. A. Ohm’s B. Electromagnetic Induction C. Kirchhoff’s Current D. Kirchhoff’s Voltage 五. 将下列短文翻译为中文。（共20分，第1题12分，第2题8分） 1. The coil to which the voltage is applied is known as the primary, while the one from which the induced voltage is obtained is known as the secondary. If the secondary has more turns than the primary, the transformer is called a step-up transformer in which the AC voltage of the secondary winding is higher than that applied to the primary winding. 第 5 页 共 6 页 If the secondary has fewer turns than the primary, the transformer is called a step-down transformer in which the AC voltage of the secondary winding is lower than that applied to the primary winding. In a well-built transformer the product of the secondary voltage multiplied by the secondary current is almost equal to the product of the primary voltage times the primary current. 被施加电压的绕组，称为主绕组，从中感应出电压的绕组称为辅助绕组，如果辅助绕组线圈匝数大于主绕组的线圈匝数，则称为升压变压器，升压变压器辅助绕组中的交流电压大于主绕组中的交流电压。如果辅助绕组中的线圈小于主绕组中的线圈匝数，则称为降压变压器，降压变压器辅助绕组中的交流电压小于主绕组中的交流电压。一个质量优良的变压器的二次电压同二次电流的乘积几乎等于其一次电压和一次电流的乘积。 2. Noise is probably the only topic in electronics and telecommunication with which everyone must be familiar, no matter what his or her specialization. It is ever present, and limits the performance of virtually every system. Also, the measurement of it is very contentious, with almost everybody having a different pet method of quantifying it and its effects. 噪声是从事的电子和电讯行业的人都必须很熟悉的话题，无论他或她的专业是什么。由于它的存在，几乎每一个系统的性能都受到了限制。此外，它的测量是非常有争议的，几乎每个人都有对它造成影响的不同判断标准。 六. 将下列句子翻译为英文。（共15分，每题3分） 1. 我们将大规模发展电力工业。 Our large-scale development of power industry. 2. 这台发动机一直运转良好。 This engine has been running well. 3. 电流在电路中流动的速度是非常快的。 Current flow in the circuit speed is very fast. 4. 如果使用变压器，低电压的电力就能转换成高电压的电力。 If using a transformer, low voltage electricity can be converted into high-voltage electricity. 5. 这一现象我们称之为电磁感应。 This phenomenon is called electromagnetic induction. 第 6 页 共 6 页

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