西交2012春季专业英语离线作业及答案.doc

成绩西安交通大学现代远程教育考试卷课 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 computers 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, . _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 parameters4. 周期电流 _ Periodic current _ 5. _负反馈_ negative feedback6. 直轴 _ Direct axis _ 7. 有功电流分量 _ Active component of current _ 8. _无功电流_ reactive current current9. 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 sources2. An electric heater draws 10 A from a 120V line. The resistance of the heater is _. A. 1200 B. 120 C. 12 D. 1.23. The algebraic sum of all voltages around a loop is _. A. zero B. indefinite value C. sum of voltage rises D. sum of voltage drops4. 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. Generators7. 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 transformers8. 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 form9. 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 bits10. 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. 60011. 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 processing12. _ 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 card13. A computers 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 language15. 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 processing16. In a coal-fired power plant, an electrostatic precipitator is used to remove _ from the combustion gases. A. solid particle B. C. CO D. water vapour17. 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 emissions18. The hydropower is well suited for switching according to _ command to meet changing power needs. A. a consumers B. a users C. a dispatchers D. an operators19. The total transfer function for and in cascade is不会_. A. B. C. D. 20. The systems 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 observability21. The Buck（降压式变换器） is a _ converter. A. voltage step-up B. current step-down C. current step-up D. resistance22. A frequency response is a function of the variable _. A. B. C. D. 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. octaves24. 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 current25. The primary winding is connected to _. A. the power source B. the load C. the measurement instrument D. the motor26. Copper losses are _ losses in the primary and secondary windings of the transformer core. A. inductive B. capacitive C. resistive D. reactive27. The relation results in _. A. null B. identity C. indefinite value D. zero28. The notebook computers use _ as standard display equipment. A. CRT display B. LCDs C. LED D. TV screen29. 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 card30. The transformer is a straightforward application of Faradays _ Law. A. Ohms B. Electromagnetic Induction C. Kirchhoffs Current D. Kirchhoffs 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 fami