沈阳工业大学电机理论2019年考博试题真题

沈阳工程学院机电控制工程基础考试试卷及参考答案1一、单项选择题（5’）1.特征方程式的所有实根都为负，共轭复根都具有负实部，是线性控制系统稳定的（）。

A、充分条件B、必要条件C、充分必要条件D、初始条件答案：A2.用频率域分析法分析控制系统时，最常用的典型输入信号是（）。

A、脉冲信号B、斜坡信号C、阶跃信号D、正弦信号答案：D3.I型开环系统对数幅频特性图的低频渐进线与w轴的交点为w=（）。

A、KsB、eC、KyD、Kd答案：A4.I型系统开环对数幅频渐近特性的低频段斜率为（）。

A. 负40(dB/dec)B. 负20(dB/dec)C．0(dB/dec)D．20(dB/dec)答案：B5.系统特征方程式的所有根均在根平面的左半部分是系统稳定的（）。

A．充分条件B ．必要条件C ．充分必要条件D. 以上都不是答案：B6.单位反馈控制系统由输入信号引起的稳态误差与开环传递函数中的哪个环节的个数有关？（ ）A 、微分环节B 、惯性环节C 、积分环节D 、振荡环节答案：C7.设二阶微分环节的传递函数是G(s)=s^2+2s+4，则其对数幅频特性的高频段的渐近线斜率为（ ）。

A 、-40B 、-20C 、40D 、20答案：A8.以下系统中，属于最小相位系统的是（ ）。

A ．s s G 01.011)(-=B ．s s G 01.011)(+=C ．101.01)(-=s s G D ．)1.01(1)(s s s G -=答案：B9.正弦函数cos(t ω)的拉氏变换是（ ）。

A. ω+s 1B. 22s ω+ωC. 22s sω+ D. 22s 1ω+答案：C10.描述RLC 电路的线性常微分方程的阶次是（ ）。

A 、零阶B 、一阶C 、二阶D 、三阶答案：B11.方框图的转换，所遵循的原则为（ ）。

A 、结构不变B 、等效C 、环节个数不变D 、每个环节的输入输出量不变答案：B12.改善系统在参考输入作用下的稳态性能的方法是增加（）。

沈阳工业大学电机与电器专业考研沈阳工业大学电机与电器学科由原电机和电器两个二级学科合并而成。

1979年开始招收研究生，1984年获硕士学位授予权。

电机和电器学科分别于1990年和1996年获得博士学位授予权，根据国家学科调整，电机学科和电器学科于1997年合并为电机与电器学科。

2001年建立电气工程一级学科博士后流动站，2002年电机与电器学科被批准为国家重点学科。

该学科现有工程院院士1人，博士生导师8人，教授16人，副教授20人及高级工程师3人，具有博士学位和正在攻读博士学位的教师23人，青年教师全部具有硕士学位。

现有博士生71人，硕士生140人，所在的“电气工程及其自动化”专业现有本科生900余人。

该学科注重应用基础和学科交叉研究，同时重视高科技产品开发，为国民经济主战场服务。

该学科曾获国家科技进步二等奖2项、三等奖1项，省部级科技进步一等奖4项，二等奖12项。

1998年以来承担9项国家自然科学基金项目，7项国家科技攻关和863项目，以及其他科研项目100余项，研究经费达5100余万元。

获国家级及省部级科技成果奖励7项，出版专著9部，发表学术论文400余篇，收入sci、ei、istp三大检索论文80余篇。

该学科的主要研究方向有：特种电机及其控制技术、电力电子电机及其控制、电气装备电磁场分析与优化设计、电气设备软件工程、现代电器理论及装备、智能化电器等。

工程院院士唐任远教授是我国从事稀土永磁电机研究的主要奠基人之一，在稀土永磁电机应用基础理论研究与高效高力能密度永磁电机产品开发上取得了多项国内外注目的研究成果，在建成教育部稀土永磁应用工程研究中心的基础上，目前正在建设国家稀土永磁电机技术研究中心。

该学科在新型风力发电机及其控制系统的研究上独具特色，20多年来先后独立开发研制了从数百瓦到数百千瓦、直到兆瓦级的风力发电机组，以及方波风力发电机和变速恒频风力发电机等多种新型高效风力发电机，目前正在承担国家863项目“mw级变速恒频风力发电机组”的研制任务。

电气考研/考博面试问题与答案汇总2019修订增补版电路原理1、特勒根定理，戴维南定理特勒根定理：拓扑结构相同的两个电路网络，一个电路中所有支路电压与另一个电路中对应支路电流的乘积之和为零。

載维南定理：任一线性电阻二端网络对外部的作用与一电压源和电阻串联而成的电路等效，电压源的值是该网络两端断开时的电压，电阻是网络中独立源不作用时，由二端网络的两端点视入的等效电阻。

2、零状态响应，零输入响应，自由分量，强制分量的关系一个线性时不变电路或系统的响应可以分解为零状态响应和零输入响应的叠加，也可以分解为自由分量和强制分量的叠加。

其中零状态响应中既包含自由分量，又包含强制分量。

零输入响应只包含自由分量，由系统的内部结构性能决定，故可以反应系统的特性。

3、带内阻恒压源外接电阻负载，电阻越大，电流越小，输出功率越小。

试判断其正确性。

不正确。

电阻越大输出功率不一定越小，当电阻负载和内阻相等的时候，输出功率最大。

4、三相对称负载，接到三相对称电源上，当负载为D连接和Y连接时吸收的功率之比。

两种接法的线电压是一样的，但是D连接的线电流是Y连接的3倍，故吸收的功率之比是3：1。

5、如何计算二端口网络的功率？并用其解析两表法的正确性u1i1+u2i26、一个有内阻的电压源接电阻负载，问在电阻负载上串联一个电阻和并联一个电阻，电阻上消耗的功率如何变化取决于原来的电阻负载与电压源内阻的大小关系：当电阻负载小于内阻时，串联电阻功率变大，并联电阻功率变小；当电阻负载大于内阻时，串联电阻功率变小，并联电阻功率变大。

7、i=5cos(t),i=3cos(t)+4cos(2t),i=3cos(t)+4cos(t+60),问哪两个信号的有效值一样。

都一样。

8、理想运放理想化的假设假设放大倍数为无穷大，输入端的输入电阻为无穷大，输出阻抗为零。

10、两个电源,其中一个变为原来的K倍,负载上的电流变为原来的K倍.判断正确性.错误11、用3种方法测量RL线圈的R、L.（1）直流测R，交流则Z模（2）直流测R，交流用功率表测功率因数（3）串联知道电容值的电容后加可调频的电源，调节电源频率到电流最大，记下此时的电压大小、频率、电流大小，利用串联谐振频率计算公式可以算出L.12、举三个电路等效的例子載维南等效，诺顿等效，pi型等效电路。

电机设计第一章1. 电机常数CA 和利用系数KA 的物理意义是什么？答：CA ：大体反映了产生单位计算转矩所消耗的有效材料。

KA ：单位体积有效材料能产生的计算转矩。

2. 什么是主要尺寸关系是？根据他可以得出什么结论？答：主要尺寸关系式为：D2lefn/P ’=6.1/(αp ’KNmKdpAB δ)，根据这个关系式得到的重要结论有:①电机的主要尺寸由其计算功率P ’和转速n 之比P ’/n 或计算转矩T 所决定;②电磁负荷A 和B δ不变时，相同功率的电机，转速较高的，尺寸较小；尺寸相同的电机，转速较高的，则功率较大。

这表明提高转速可减小电机的体积和重量。

③转速一定时，若直径不变而采取不同长度，则可得到不同功率的电机。

④由于极弧系数αp ’、 KNm 与Kd 的数值一般变化不大，因此电机的主要尺寸在很大程度上和选用的电磁负荷A 和B δ有关。

电磁负荷选得越高电机的尺寸就越小。

3.什么是电机中的几何相似定律？为何在可能情况下，总希望用大功率电机来代替总功率相等的小功率电机？为何冷却问题对于大电机比对小电机更显得重要?答：在转速相同的情况，当Db a D =lb la =hb ha =bb ba =…下，'P G ∝'P Gef ∝'P P ∝'4/3'P P ∝P4/1'1即当B 和J 的数值保持不变时，对一系列功率递增，几何形状相似的电机，每单位功率所需有效填料的重量、成本及产生损耗均怀功率的1/4次方成反比。

用大功率电机代替总功率相等的数台小电机的原因是随着单机容量的增加，其效材料的重量G、成本Gef相对容量的增加要慢。

因此用大功率电机代替总功率相等的数台小电功率机。

其有效材料的利用率提高了。

损耗增加相对容量慢，因此效率提高了。

冷却问题对大功率电机比对小功率电机更显得重要的原因是电机损耗与长度l的立方成成正比，而冷却表面却与长度的平方成正比。

功率上升，长度变长，损耗增加大于冷却的增加。

沈阳工业大学2019 年博士研究生招生考试题签(请考生将题答在试题紙上，答在题签上无效）Part I Vocabulary (15 points, 0.5 for each)Directions: In this section, there are 30 sentences, each with one word or phrase underlined. Choose the one from the 4 choices marked A, B, C and D that best keeps the meaning of the sentence. Then mark the corresponding letter with a single line on the ANSWER SHEET1.The of AIDS has led to an expansion in research seeking a cureA. InnovationB. selectionC.proliferationD.Conviction2.Most importantly, such an experience helps a heightened sensitivity to other cultures andwill bring about a greater appreciation of one's own culture as wellA.containB.fosterC.discoverD.censor3.The talks between China and Japan were the base of the later agreementsA. InitialB.finalC. terminalD. primitive4.Metals we found in the earl iron, lead , and copper.priseB.containC.concludepose5.Tom give me a new bicycle as for the one he lost.A.substitutpensationC.rewardD.bonus6.Over the past ten years, natural gas production has remained steady, but has risen steadily.A.ConsuinptionB.disposalC.ConditionD.disposition7.The Brons lived in a and comfortably furnished house in the countrysideA.spaciousB.sufficientC. EfficientD. Constant8.David was by his family because he worked with a gang of criminals to rob the commercialbank.A. AbolishedB.diminishedC.desertedD.dismissed9.The talks between the two leaders have reached a stage.A.criticalB.criticismC.desertedD.dismissed10.These goods are for export, though a few of them may be sold on the home market.A. essentiallypletelyC.necessarilyD.remarkably11.We love peace, yet we are not the kind of people to any military threat.A.yield upB.yield toC.yield inD.yleid at12.John used to his teacher's tone and gestures to make his classmates laugh.A.imitateB.stimulateC.initimateD. Resemble13.The professor the translation of a German novel.A.is engaged withB.is busy inC.is occupied withD.is absorbed to14. The findings appears to the laws of physics.A.violentB.ViolateC. V oluntaryD.violet15. It is rather that we do not know how many species there are in the worl D.A.embarrassingB.boringC.demandingD.Violet16. Science is still largely the causes of man kinds of cancer.A.ignorant ofB.ignorant aboutC.ignorant withD.ignorant to17. In the first several years of our economic reform, many military factories have been into civil ones in order to meet the needs of the country.A.changedB.TransformedC.ConvertedD.Altered18. Some plants are so pollution that they can only survive in a perfectly clean environment.A.sensitive toB.sensible toC.sensitive againstD.sensible against19. Don'teat choclate; it will spoil your dinner.A.Desire forB.hunger forC.appetite forD. Eager for20. To help these difficulties, some organizations have opted to group together machines that process parts which have a large set of common characteristics.A.prevailB.overcomeC.overpowerD.Defeat21. Some people find it helpful to have something to do with their hands, like , or playing witha bunch of keys.A.knittingB.BeatingC.meetingD.dining22. Althougu many experts agree that more children are overweight, there is debate over the best ways to the problem.A.pursueB.TackleC.DistinguishD.ultimately23. He has held hundreds of meetings and spent whole weeks resolving these tricky problems, but he has faile D.A.ideologicallyB.personallyC.skepticallyD.Ultimately24. Drider says it is only since Sarkozys government began discussing the matter that she has been insults, harassment and death threats.A.objected toB.inferior toC.confined toD.subject to25. Artists should cultivate their own style rather than always imitating others.A.singleB.IndividualC.privateD.separate26. The new discovery of oil is to the country’s economy.A.SignatureB.significantC.signD. significance27. After the , the employer concluded that she was suitable for the position.A.audienceB.encounterC.interviewD.arrangement28. If businessmen are taxed too much, they will no longer be motivated to work hard, with the result that income from taxation might actually .A. ShrinkB.delayC. DisperseD. Sink29. He hated wandering about and expected to find a position in the Civil Service of government.A.ExcessiveB.AccidentalC.equalD.permanen30. Doctors and researchers have to keep themselves on the latest developments in their sphere of study.A.ConvincedB.IsolatedC.HumiliatedD.updated Part IL Cloze (15 points, 1 for each)Directions: There are 15 blanks in the following passage. For each blank, there are four choices marked A, B. C and D. You should choose the ONE that best fits into the passage. Then mark the corresponding letter on the Answer Sheet with a single line through the center.Predictions of large populations of robots in industry have yet to come true. For a decade ormore, manufacturers of big robots have explained how their machines can make industry more competitive and productive. The market for 31 robots is now oversupplied, and the driving force of the robotics revolution is 32 to be with makers of machines that handle a few kilos at most.Heavy-robot manufacturers are in some difficulty 33 finding customers. They are offering big 34 just to get in the door. There has been a disappointing growth everywhere in the numbers of robots, so have to admit we are either deceiving 35 or that the market is slowly growing, "said John Reekie, Chairman of Colne Robotics. The following things must happen 36 the robotics revolution to occur. We must achieve widespread robot literacy (文化), 37 there has been a computer literacy program, there must be a robot literacy campaign. We must also achieve not just a cut in, but a collate of robot prices. Finally, some ki of artificial intelligence needs to be 38 .Colne makes educational robots and machine tools. It is small 39 with companies like ASEA. But Colne with others and departments in universities such as Surey, Manchester, possesses an advantage 40 the giants. The big companies sell very expensive robots to businesses with expert knowledge in automation. The 41 companies make robots for teaching people, and now they have realized there is a need for small, 42 robots thatThe little companies either bring their educational machines 43 an industrial standard or design from scratch. One technique that they all adopt is to choose _ 44 components where possible. The major cost of making both their models is the electronics, which will fall in price. There is 45 scope for reductions in mechanical costs. The use of standard parts, which are easily replaced, should give these robots mechanical life of something in the order of five years.31. A.small cational C.big D.business32. A.claimed B.called C.said D. told33. A.to B.with C.over D.in34. A.money B.discount C. prices D.costs35. A.ourselves B.customers panies 37. A.as if B.even though C.just as D.although38. A.capable B.possible C. probable D. available39. pared paring C.contrasted D.contrasting40. A.than B.above C.over D. from41. A.other B.big C.small D.robot42. A.expensive B. artificial cational D. low-cost43. A. up to B.to C. in D. about44. A. mechanical B.standard C.cheap D.small45. A. more B.less C. no D. leastPart Ill. Reading Comprehension (30 points, 1.5 for each)Directions: There are four passages in this part. Each of the passages is followed by five questions or unfinished statements. For each of the questions there are four choices marked A, B, C and D. Choose the best one and mark your answer on the ANSWER SHEET with a single line through the center.Passage oneSome pessimistic experts feel that the automobile is bound to fall into disuse. They see a day in the not-too-distant future when all autos will be abandoned and allowed to rust. Other authorities. However, think the auto is here to stay. They hold that the car will remain a leading means of urban travel in the foreseeable future.The motorcar will undoubtedly change significantly over the next 30 years. It should become smaller, safer, nc more economical, and should not be powered by the gasoline engine. The ear of the future should be far more Pollution-free than present types.Regardless of its power source, the auto in the future will still be the main problem in urban traffic congestion ne proposed solution to this problem is the automated highway system.When the auto enters the highway system, a retractable arm will drop from the auto and make contact with a rail, which is similar to those powering subway trains electrically. Once attached to the rail the car will become electrically powered from the system, and control of the vehicle will pass to a central computer. The computer will then monitor all of the car’s movements.The driver will use a telephone to dial instructions about his destination into the system. The computer will calculate the best route, and reserve space for the car all the way to the correct exit from the highway. The driver will then be free to relax and wait for the buzzer that will war him of his coming exit. It is estimated that an automated highway will be able to handle 10,000 vehicles per hour, compared with the 1, 500 to 2,000 vehicles that can be carried by a present-day highway46. One significant improvement in the future car will probably beA. Its power sourceB. its driving systemC. its monitoring systemD. Its seating capacity47. What is the authors main concern?A. How to render automobiles pollution-freB. How to make smaller and safer automobilesC. How to solve the problem of traffic jamsD. How to develop an automated subway system48. What provides autos with electric power in an automated highway system?A. A railB. An engine.C. A retractable armD A computer controlle49. In an automated highway system, all the driver needs to do isA. Keep in the right laneB. Wait to arrive at his destinationC. Keep in constant touch with the computer centerD inform the system of his destination by phone50. What is the authors attitude toward the future of autos?A. EnthusiastB. PessimisticC. Optimistic.D. Cautious.Passage TwoWhile jobs in science, technology, engineering and math (STEM) professions may be plentiful, many teenage unwilling to pursue a long-term career in these fields. According to a new survey, in sixth through twelfth grade felt that careers as doctors and engineers would offer the most job opportur college, but 67 percent were of two minds about whether they would pursue these careers, due to a multitude of difficulties involved.Chief among the challenges is the cost and time it takes to get a degree. According to this survey, 26 percent of respondents felt that the cost and difficulty of pursuing professionally qualifying education in these fields were too high compared with other fields. Additionally, 25 percent of students felt that these career paths were too challenging and involved too much studying.Careers as doctors and engineers were not the only places where students saw opportunities, though. According to the survey, the three career fields offering the greatest opportunity were doctors, engineers and teachers, followed by lawyers and entrepreneurs.“It's encouraging to se that more students see the value of STEM careers like engineering, but clearly STEM) ofessionals and educators can be doing more to support students along this career path, "said Jim Rooney, ASQ chair and quality engineer with ABSG Consulting That is because 25 percent of teenage respondents stated their grades in math and science arent good enough to pursue a future career in those subjects. For once, parents agreed with their children, as 53 percent of parents who responded in a similar survey were worried about the challenges these fields presented to their children. Just over al quarter of parents, 26 percent, also felt that teachers were not preparing their children enough for future careers in STEM fields.Another factor contributing to the non-pursuit of STEM jobs is the growing gender gap in education. Accord to this survey, 30 percent of girls stated that math was their most challenging subject, compared with 19 percent boys. Additionally, 33 percent of girls admitted they felt teachers did not prepare them enough for future careers in STEM careers, compared with just 9 percent of boys.The information in this survey is based on the responses of 713 students and a complementary survey of 327 parents with children between the ages of 10 and 17.51. Many students are reluctant to take up STEM jobs because of the following EXCEPTA. The hard work needed along the career pathB the high tuition they have to pay at collegeC the few work opportunities related to STEMD. The long time taken to get the acadcmic degree52. According to this passage, most students believe that careers as doctors and engineersA. Are really worth pursuingB. Promise easy employmentC. Have nothing to do with mathD. Offer fewer opportunities than lawyers53. According to Paragraph 4, Jim Rooney would like toA. advise students not to take up STEM jobsB. Become a STEM professional himselfC tell STEM professionals to learn moreD see students get more help into STEM careers54. The growing gender gap mentioned in Paragraph 6 refers to the finding thatA. Fewer girls want to engage in STEM careers than boysB. More girls hope to take up STEM than boysC. There are far more male students than female onesD. Boys are more likely to get Stem-related jobs55. This passage is intended toA encourage students to undertake STEM jobB. Describe the difficulty facing STEM studentsC. Introduce the result of a survey on STEM jobsD help college graduates to find STEM jobsPassage ThreeMost people believe the key to happy and productive retirement years is staying healthy. Yet, it's not just about diet and exercise. How you manage your money often determines your level of stress, which, if too high, may lead to chronic health problems like heart diseases.So you'll have to do more than switch to whole wheat and start jogging every day. Your health also depends on feeling good about and in control of your finances. Not a lot of people understand that-and relatively few are doing much about it.In a survey, Principal Financial found that just 48% of American workers are monitoring their spending do from 58% two years ago. Fewer are reevaluating their investments, and while more are using a budget, the rate is still low at just 28%. In other words, they are casual about their money Most American workers see the link between wealth and health as one directional: Staying healthy is the ticket to saving on health care costs and to financial security in retirement. In the survey, 84% said being physically health is good for their financial future and 76% said if they spend money on their health or things they enjoy now they will avoid major health costs later in life.Yet it's not that simple. Good health comes with its own financial demands. Living healthy means living longer, which is wonderful. But without a traditional pension or other source of guaranteed lifetime income how will you pay for all those extra years? You'ii need to save tens of thousands of dollars more than you may have figured in your lifetime-and still there is no guarantee you won't need costly, end-of-life services.None of this is to say that living longer and healthier isnt a blessing, and probably even less a demand on your resources than developing chronic illness and passing away early. But the link between financial health and physical health goes both ways. In the survey, workers were far more likely to rate themselves physically healthy (53%) than financially healthy (31%), suggesting theysee it as a one-way street. But it's also the case that feeling in control of your wealth-no matter how much you have-leads to better health.56. In the first paragraph, the author expresses the belief thatA. Nothing but diet and exercise determines healthB. Diet and exercise have nothing to do with healthC. Health after retirement depends on money aloneD. Wealth also plays a role in staying healthy57. Which of the following statements is true about the workers surveyed?A. They don, t care about their retired life at allB. They believe wealth means a happy retired life.C. They are not in control of their moneyD. They have to save money now for future health58. In the last paragraph, "one-way street"probably means.A. Financial health leads to physical healthB. Physical health leads to financial healthC. financial health equals physical healthD. Financial health repels physical health59. The author is very likely to argue in the last paragraph thatA financial health and physical health are mutually dependentB neither wealth nor health makes any difference to happinesC. Physical health depends on nothing but financial healthD taking care of your wealth will not lead to better health60. The author of this passage intends to argue thatA staying healthy is impossible without accumulating much wealthB being physically healthy can eventually contribute to your wealthC feeling good about your finance is also of health benefitD. A large fortune will increase the chance of deterioration of healthPassage FourThe value a healthy environment provides is invisible in the global cconomy, leading to ecosystem degradation and species loss, according to the Economics of Ecosystems and Biodiversity (TEEB) study released recently. For example, bees and other insects jumping from flower to flower provide an essential service for crop production. Valued at an astonishing $200 billion.As the value is inconspicuous, we tend to ignore it. However, the"broken"financial system must be reformed o that the environment and the valuable services it provides are incorporated into every decision and ansaction, the report concludes. That is vital not only for slowing environmental destruction and species loss, but for modern economics to flourish, Sukhdev, leader of the study, said.While most cost enefit analyses look at natual resoures that can be extracted, such as gold, timber and food, those products only account for one-third of the total economic value provided by the environment, the report said, other "ecosystem services", such as pollination, forests fltering drinking water and wetlands providing flood protection, make up the other two-thirds.Currently, businesses do not pay for the loss of services caused by production or development. Estimated at 2.2 I trillion annually for the top 3, 000 listed companies, those costs are passed onto society, or externalized."We are at a stage now where the rate of loss of ecosystem services and the rate of loss of biodiversity is so severe we can not treat them as mere externalities of economics. Said Sukhde.To internalize environmental values and crops. The TEEB report recommends implementing a variety of financial tools, such as charging for services, creating environmentally friendly markets with eco-labelling and providing financial incentives and subsidies for environmentally friendly businesses.Normal business practices should report negative environmental extemalities and offset their impacts so they have a net zero impact, or even a net positive impact, the report said. And subsidies for industries harming the nvironment, such as fossil fuels, should be phased out.Environmental protection can also save money, according to the TEEB report. For example, New York more than S 6 billion by paying farmers about SI billion to change management of runoff to reduce the water pollution, rather than build a S 6 billion to S& billion waste water treatment plant that would have cost between S 300 million and $500 million a year to operate.But convincing board rooms and consumers across the globe to start paying for things that have been free in the pasl is L guing to be easy Sukhdev said it is not going to happen overnight--new, emerging models will begin to compete with old, lingering ones.“ it could happen, but not in today’s environment,”said Patrick micbaels, a senior fellow in environmental studies at the cato institude. "Right now, people-and it's not just the U.S--people are worried about economic contractions more than they are about environmental protection.”61. The example of bees and other insects in the first paragraph is used to illustrate thatA. Those insects play an essential role in crop productionB. They are essential for the global economy as well as the environmentC a healthy environment provides inconspicuous value in the global economyD insect activities have a crucial impact on global ecosystem and biodiversity62. Why must the"broken" financial system be reformed according to the report?A. The value environment provides should become visible in the global economy.B. Ecosystem services should be considered when making decisions in businessC. The current economic value provided by the environment tends t be ignoredD. To reform the "broken "financial system is vital to slow ecosystem degradation63. What do we learn about the loss of ecosystem services?A. It can be seen as an externality of economicsB. It is estimated at S 2.2 trillion every yearC. It is transferred to society or externalizedD. It is caused and paid for by businesses.64. What does the TEEB report suggest on handling environmental values and costs?A. Carrying out a succession of financial measures.B. Punishing farmers for changing management of runoff.C. Providing financial support for both businesses and farmersD. Increasing subsidies for environmentally disabled industries65. What can we know from what Patrick Michaels said in the last paragrap?A. People are worried more about economy than the environment.B. Nowadays it is hard for people to pay for what used to be freeC New emerging models will take the place of old ones in the endD. Right nowz the global economy is prosperous rather than depressedPart IV Put the following into Chinese. (15 points)My goals in writing this book are twofold.First, I hope to paint a picture of what it was like to serve as president for eight straight years. My conviction is that it is virtually impossible to reach definite conclusions about my presidency for several decades. The passage time allows passions) l, results to clarify, and scholars to compare different approaches. This book contribute to studies on this period in American history.Second, I gave an exhaustive account of the options I weighed and principles I complied with to give you better sense of why I made the decisions I did. This book is primarily based on my recollections. If there inaccuracies, the responsibility is mine.Part V Essay Writing (25 points)Write a composition of about 200 words on the following topic:My Viewpoint on Wide-spread WechatYou are to write in three parts.In the first part, make a description of the popularity of Wechat with examplesIn the second part, illustrate your views on the advantage and disadvantage of Using Wechat In the last part, bring what you have written to a natural conclusion or a summaryMarks will be awarded for content, organization, grammar and appropriateness, Failure to follow the instructions。

沈阳工业大学2019 年博士研究生招生考试题签(请考生将题答在试题紙上，答在题签上无效）Part I Vocabulary (15 points, 0.5 for each)Directions: In this section, there are 30 sentences, each with one word or phrase underlined. Choose the one from the 4 choices marked A, B, C and D that best keeps the meaning of the sentence. Then mark the corresponding letter with a single line on the ANSWER SHEET1.The of AIDS has led to an expansion in research seeking a cureA. InnovationB. selectionC.proliferationD.Conviction2.Most importantly, such an experience helps a heightened sensitivity to other cultures andwill bring about a greater appreciation of one's own culture as wellA.containB.fosterC.discoverD.censor3.The talks between China and Japan were the base of the later agreementsA. InitialB.finalC. terminalD. primitive4.Metals we found in the earl iron, lead , and copper.priseB.containC.concludepose5.Tom give me a new bicycle as for the one he lost.A.substitutpensationC.rewardD.bonus6.Over the past ten years, natural gas production has remained steady, but has risen steadily.A.ConsuinptionB.disposalC.ConditionD.disposition7.The Brons lived in a and comfortably furnished house in the countrysideA.spaciousB.sufficientC. EfficientD. Constant8.David was by his family because he worked with a gang of criminals to rob the commercialbank.A. AbolishedB.diminishedC.desertedD.dismissed9.The talks between the two leaders have reached a stage.A.criticalB.criticismC.desertedD.dismissed10.These goods are for export, though a few of them may be sold on the home market.A. essentiallypletelyC.necessarilyD.remarkably11.We love peace, yet we are not the kind of people to any military threat.A.yield upB.yield toC.yield inD.yleid at12.John used to his teacher's tone and gestures to make his classmates laugh.A.imitateB.stimulateC.initimateD. Resemble13.The professor the translation of a German novel.A.is engaged withB.is busy inC.is occupied withD.is absorbed to14. The findings appears to the laws of physics.A.violentB.ViolateC. V oluntaryD.violet15. It is rather that we do not know how many species there are in the worl D.A.embarrassingB.boringC.demandingD.Violet16. Science is still largely the causes of man kinds of cancer.A.ignorant ofB.ignorant aboutC.ignorant withD.ignorant to17. In the first several years of our economic reform, many military factories have been into civil ones in order to meet the needs of the country.A.changedB.TransformedC.ConvertedD.Altered18. Some plants are so pollution that they can only survive in a perfectly clean environment.A.sensitive toB.sensible toC.sensitive againstD.sensible against19. Don'teat choclate; it will spoil your dinner.A.Desire forB.hunger forC.appetite forD. Eager for20. To help these difficulties, some organizations have opted to group together machines that process parts which have a large set of common characteristics.A.prevailB.overcomeC.overpowerD.Defeat21. Some people find it helpful to have something to do with their hands, like , or playing witha bunch of keys.A.knittingB.BeatingC.meetingD.dining22. Althougu many experts agree that more children are overweight, there is debate over the best ways to the problem.A.pursueB.TackleC.DistinguishD.ultimately23. He has held hundreds of meetings and spent whole weeks resolving these tricky problems, but he has faile D.A.ideologicallyB.personallyC.skepticallyD.Ultimately24. Drider says it is only since Sarkozys government began discussing the matter that she has been insults, harassment and death threats.A.objected toB.inferior toC.confined toD.subject to25. Artists should cultivate their own style rather than always imitating others.A.singleB.IndividualC.privateD.separate26. The new discovery of oil is to the country’s economy.A.SignatureB.significantC.signD. significance27. After the , the employer concluded that she was suitable for the position.A.audienceB.encounterC.interviewD.arrangement28. If businessmen are taxed too much, they will no longer be motivated to work hard, with the result that income from taxation might actually .A. ShrinkB.delayC. DisperseD. Sink29. He hated wandering about and expected to find a position in the Civil Service of government.A.ExcessiveB.AccidentalC.equalD.permanen30. Doctors and researchers have to keep themselves on the latest developments in their sphere of study.A.ConvincedB.IsolatedC.HumiliatedD.updated Part IL Cloze (15 points, 1 for each)Directions: There are 15 blanks in the following passage. For each blank, there are four choices marked A, B. C and D. You should choose the ONE that best fits into the passage. Then mark the corresponding letter on the Answer Sheet with a single line through the center.Predictions of large populations of robots in industry have yet to come true. For a decade ormore, manufacturers of big robots have explained how their machines can make industry more competitive and productive. The market for 31 robots is now oversupplied, and the driving force of the robotics revolution is 32 to be with makers of machines that handle a few kilos at most.Heavy-robot manufacturers are in some difficulty 33 finding customers. They are offering big 34 just to get in the door. There has been a disappointing growth everywhere in the numbers of robots, so have to admit we are either deceiving 35 or that the market is slowly growing, "said John Reekie, Chairman of Colne Robotics. The following things must happen 36 the robotics revolution to occur. We must achieve widespread robot literacy (文化), 37 there has been a computer literacy program, there must be a robot literacy campaign. We must also achieve not just a cut in, but a collate of robot prices. Finally, some ki of artificial intelligence needs to be 38 .Colne makes educational robots and machine tools. It is small 39 with companies like ASEA. But Colne with others and departments in universities such as Surey, Manchester, possesses an advantage 40 the giants. The big companies sell very expensive robots to businesses with expert knowledge in automation. The 41 companies make robots for teaching people, and now they have realized there is a need for small, 42 robots thatThe little companies either bring their educational machines 43 an industrial standard or design from scratch. One technique that they all adopt is to choose _ 44 components where possible. The major cost of making both their models is the electronics, which will fall in price. There is 45 scope for reductions in mechanical costs. The use of standard parts, which are easily replaced, should give these robots mechanical life of something in the order of five years.31. A.small cational C.big D.business32. A.claimed B.called C.said D. told33. A.to B.with C.over D.in34. A.money B.discount C. prices D.costs35. A.ourselves B.customers panies 37. A.as if B.even though C.just as D.although38. A.capable B.possible C. probable D. available39. pared paring C.contrasted D.contrasting40. A.than B.above C.over D. from41. A.other B.big C.small D.robot42. A.expensive B. artificial cational D. low-cost43. A. up to B.to C. in D. about44. A. mechanical B.standard C.cheap D.small45. A. more B.less C. no D. leastPart Ill. Reading Comprehension (30 points, 1.5 for each)Directions: There are four passages in this part. Each of the passages is followed by five questions or unfinished statements. For each of the questions there are four choices marked A, B, C and D. Choose the best one and mark your answer on the ANSWER SHEET with a single line through the center.Passage oneSome pessimistic experts feel that the automobile is bound to fall into disuse. They see a day in the not-too-distant future when all autos will be abandoned and allowed to rust. Other authorities. However, think the auto is here to stay. They hold that the car will remain a leading means of urban travel in the foreseeable future.The motorcar will undoubtedly change significantly over the next 30 years. It should become smaller, safer, nc more economical, and should not be powered by the gasoline engine. The ear of the future should be far more Pollution-free than present types.Regardless of its power source, the auto in the future will still be the main problem in urban traffic congestion ne proposed solution to this problem is the automated highway system.When the auto enters the highway system, a retractable arm will drop from the auto and make contact with a rail, which is similar to those powering subway trains electrically. Once attached to the rail the car will become electrically powered from the system, and control of the vehicle will pass to a central computer. The computer will then monitor all of the car’s movements.The driver will use a telephone to dial instructions about his destination into the system. The computer will calculate the best route, and reserve space for the car all the way to the correct exit from the highway. The driver will then be free to relax and wait for the buzzer that will war him of his coming exit. It is estimated that an automated highway will be able to handle 10,000 vehicles per hour, compared with the 1, 500 to 2,000 vehicles that can be carried by a present-day highway46. One significant improvement in the future car will probably beA. Its power sourceB. its driving systemC. its monitoring systemD. Its seating capacity47. What is the authors main concern?A. How to render automobiles pollution-freB. How to make smaller and safer automobilesC. How to solve the problem of traffic jamsD. How to develop an automated subway system48. What provides autos with electric power in an automated highway system?A. A railB. An engine.C. A retractable armD A computer controlle49. In an automated highway system, all the driver needs to do isA. Keep in the right laneB. Wait to arrive at his destinationC. Keep in constant touch with the computer centerD inform the system of his destination by phone50. What is the authors attitude toward the future of autos?A. EnthusiastB. PessimisticC. Optimistic.D. Cautious.Passage TwoWhile jobs in science, technology, engineering and math (STEM) professions may be plentiful, many teenage unwilling to pursue a long-term career in these fields. According to a new survey, in sixth through twelfth grade felt that careers as doctors and engineers would offer the most job opportur college, but 67 percent were of two minds about whether they would pursue these careers, due to a multitude of difficulties involved.Chief among the challenges is the cost and time it takes to get a degree. According to this survey, 26 percent of respondents felt that the cost and difficulty of pursuing professionally qualifying education in these fields were too high compared with other fields. Additionally, 25 percent of students felt that these career paths were too challenging and involved too much studying.Careers as doctors and engineers were not the only places where students saw opportunities, though. According to the survey, the three career fields offering the greatest opportunity were doctors, engineers and teachers, followed by lawyers and entrepreneurs.“It's encouraging to se that more students see the value of STEM careers like engineering, but clearly STEM) ofessionals and educators can be doing more to support students along this career path, "said Jim Rooney, ASQ chair and quality engineer with ABSG Consulting That is because 25 percent of teenage respondents stated their grades in math and science arent good enough to pursue a future career in those subjects. For once, parents agreed with their children, as 53 percent of parents who responded in a similar survey were worried about the challenges these fields presented to their children. Just over al quarter of parents, 26 percent, also felt that teachers were not preparing their children enough for future careers in STEM fields.Another factor contributing to the non-pursuit of STEM jobs is the growing gender gap in education. Accord to this survey, 30 percent of girls stated that math was their most challenging subject, compared with 19 percent boys. Additionally, 33 percent of girls admitted they felt teachers did not prepare them enough for future careers in STEM careers, compared with just 9 percent of boys.The information in this survey is based on the responses of 713 students and a complementary survey of 327 parents with children between the ages of 10 and 17.51. Many students are reluctant to take up STEM jobs because of the following EXCEPTA. The hard work needed along the career pathB the high tuition they have to pay at collegeC the few work opportunities related to STEMD. The long time taken to get the acadcmic degree52. According to this passage, most students believe that careers as doctors and engineersA. Are really worth pursuingB. Promise easy employmentC. Have nothing to do with mathD. Offer fewer opportunities than lawyers53. According to Paragraph 4, Jim Rooney would like toA. advise students not to take up STEM jobsB. Become a STEM professional himselfC tell STEM professionals to learn moreD see students get more help into STEM careers54. The growing gender gap mentioned in Paragraph 6 refers to the finding thatA. Fewer girls want to engage in STEM careers than boysB. More girls hope to take up STEM than boysC. There are far more male students than female onesD. Boys are more likely to get Stem-related jobs55. This passage is intended toA encourage students to undertake STEM jobB. Describe the difficulty facing STEM studentsC. Introduce the result of a survey on STEM jobsD help college graduates to find STEM jobsPassage ThreeMost people believe the key to happy and productive retirement years is staying healthy. Yet, it's not just about diet and exercise. How you manage your money often determines your level of stress, which, if too high, may lead to chronic health problems like heart diseases.So you'll have to do more than switch to whole wheat and start jogging every day. Your health also depends on feeling good about and in control of your finances. Not a lot of people understand that-and relatively few are doing much about it.In a survey, Principal Financial found that just 48% of American workers are monitoring their spending do from 58% two years ago. Fewer are reevaluating their investments, and while more are using a budget, the rate is still low at just 28%. In other words, they are casual about their money Most American workers see the link between wealth and health as one directional: Staying healthy is the ticket to saving on health care costs and to financial security in retirement. In the survey, 84% said being physically health is good for their financial future and 76% said if they spend money on their health or things they enjoy now they will avoid major health costs later in life.Yet it's not that simple. Good health comes with its own financial demands. Living healthy means living longer, which is wonderful. But without a traditional pension or other source of guaranteed lifetime income how will you pay for all those extra years? You'ii need to save tens of thousands of dollars more than you may have figured in your lifetime-and still there is no guarantee you won't need costly, end-of-life services.None of this is to say that living longer and healthier isnt a blessing, and probably even less a demand on your resources than developing chronic illness and passing away early. But the link between financial health and physical health goes both ways. In the survey, workers were far more likely to rate themselves physically healthy (53%) than financially healthy (31%), suggesting theysee it as a one-way street. But it's also the case that feeling in control of your wealth-no matter how much you have-leads to better health.56. In the first paragraph, the author expresses the belief thatA. Nothing but diet and exercise determines healthB. Diet and exercise have nothing to do with healthC. Health after retirement depends on money aloneD. Wealth also plays a role in staying healthy57. Which of the following statements is true about the workers surveyed?A. They don, t care about their retired life at allB. They believe wealth means a happy retired life.C. They are not in control of their moneyD. They have to save money now for future health58. In the last paragraph, "one-way street"probably means.A. Financial health leads to physical healthB. Physical health leads to financial healthC. financial health equals physical healthD. Financial health repels physical health59. The author is very likely to argue in the last paragraph thatA financial health and physical health are mutually dependentB neither wealth nor health makes any difference to happinesC. Physical health depends on nothing but financial healthD taking care of your wealth will not lead to better health60. The author of this passage intends to argue thatA staying healthy is impossible without accumulating much wealthB being physically healthy can eventually contribute to your wealthC feeling good about your finance is also of health benefitD. A large fortune will increase the chance of deterioration of healthPassage FourThe value a healthy environment provides is invisible in the global cconomy, leading to ecosystem degradation and species loss, according to the Economics of Ecosystems and Biodiversity (TEEB) study released recently. For example, bees and other insects jumping from flower to flower provide an essential service for crop production. Valued at an astonishing $200 billion.As the value is inconspicuous, we tend to ignore it. However, the"broken"financial system must be reformed o that the environment and the valuable services it provides are incorporated into every decision and ansaction, the report concludes. That is vital not only for slowing environmental destruction and species loss, but for modern economics to flourish, Sukhdev, leader of the study, said.While most cost enefit analyses look at natual resoures that can be extracted, such as gold, timber and food, those products only account for one-third of the total economic value provided by the environment, the report said, other "ecosystem services", such as pollination, forests fltering drinking water and wetlands providing flood protection, make up the other two-thirds.Currently, businesses do not pay for the loss of services caused by production or development. Estimated at 2.2 I trillion annually for the top 3, 000 listed companies, those costs are passed onto society, or externalized."We are at a stage now where the rate of loss of ecosystem services and the rate of loss of biodiversity is so severe we can not treat them as mere externalities of economics. Said Sukhde.To internalize environmental values and crops. The TEEB report recommends implementing a variety of financial tools, such as charging for services, creating environmentally friendly markets with eco-labelling and providing financial incentives and subsidies for environmentally friendly businesses.Normal business practices should report negative environmental extemalities and offset their impacts so they have a net zero impact, or even a net positive impact, the report said. And subsidies for industries harming the nvironment, such as fossil fuels, should be phased out.Environmental protection can also save money, according to the TEEB report. For example, New York more than S 6 billion by paying farmers about SI billion to change management of runoff to reduce the water pollution, rather than build a S 6 billion to S& billion waste water treatment plant that would have cost between S 300 million and $500 million a year to operate.But convincing board rooms and consumers across the globe to start paying for things that have been free in the pasl is L guing to be easy Sukhdev said it is not going to happen overnight--new, emerging models will begin to compete with old, lingering ones.“ it could happen, but not in today’s environment,”said Patrick micbaels, a senior fellow in environmental studies at the cato institude. "Right now, people-and it's not just the U.S--people are worried about economic contractions more than they are about environmental protection.”61. The example of bees and other insects in the first paragraph is used to illustrate thatA. Those insects play an essential role in crop productionB. They are essential for the global economy as well as the environmentC a healthy environment provides inconspicuous value in the global economyD insect activities have a crucial impact on global ecosystem and biodiversity62. Why must the"broken" financial system be reformed according to the report?A. The value environment provides should become visible in the global economy.B. Ecosystem services should be considered when making decisions in businessC. The current economic value provided by the environment tends t be ignoredD. To reform the "broken "financial system is vital to slow ecosystem degradation63. What do we learn about the loss of ecosystem services?A. It can be seen as an externality of economicsB. It is estimated at S 2.2 trillion every yearC. It is transferred to society or externalizedD. It is caused and paid for by businesses.64. What does the TEEB report suggest on handling environmental values and costs?A. Carrying out a succession of financial measures.B. Punishing farmers for changing management of runoff.C. Providing financial support for both businesses and farmersD. Increasing subsidies for environmentally disabled industries65. What can we know from what Patrick Michaels said in the last paragrap?A. People are worried more about economy than the environment.B. Nowadays it is hard for people to pay for what used to be freeC New emerging models will take the place of old ones in the endD. Right nowz the global economy is prosperous rather than depressedPart IV Put the following into Chinese. (15 points)My goals in writing this book are twofold.First, I hope to paint a picture of what it was like to serve as president for eight straight years. My conviction is that it is virtually impossible to reach definite conclusions about my presidency for several decades. The passage time allows passions) l, results to clarify, and scholars to compare different approaches. This book contribute to studies on this period in American history.Second, I gave an exhaustive account of the options I weighed and principles I complied with to give you better sense of why I made the decisions I did. This book is primarily based on my recollections. If there inaccuracies, the responsibility is mine.Part V Essay Writing (25 points)Write a composition of about 200 words on the following topic:My Viewpoint on Wide-spread WechatYou are to write in three parts.In the first part, make a description of the popularity of Wechat with examplesIn the second part, illustrate your views on the advantage and disadvantage of Using Wechat In the last part, bring what you have written to a natural conclusion or a summaryMarks will be awarded for content, organization, grammar and appropriateness, Failure to follow the instructions。

第一章 导论1．1 电机和变压器的磁路常采用什么材料制成？这些材料各有哪些主要特性？1．2 磁滞损耗和涡流损耗是什么原因引起的？它们的大小与哪些因素有关？1．3 变压器电动势、运动电动势产生的原因有什么不同？其大小与哪些因素有关？1．4 自感系数的大小与哪些因素有关？有两个匝数相等的线圈，一个绕在闭合铁心上，一个绕在木质材料上，哪一个的自感系数大？哪一个的自感系数是常数？哪一个的自感系数是变数，随什么原因变化？1．5 在图1-1中，若一次绕组外加正弦电压1u 、绕组电阻1R 、电流1i 时，问（1）绕组内为什么会感应出电动势？（2）标出磁通、一次绕组的自感电动势、二次绕组的互感电动势的正方向；（3）写出一次侧电压平衡方程式；（4）当电流1i 增加或减小时，分别标出两侧绕组的感应电动势的实际方向。

1．6 在图1-1中，如果电流1i 在铁心中建立的磁通是t m ωsin Φ=Φ，二次绕组的匝数是2N ，试求二次绕组内感应电动势有效值的计算公式，并写出感应电动势与磁通量关系的复数表示式。

1．7 有一单匝矩形线圈与一无限长导体在同一平面上，如图1-2所示，试分别求出下列条件下线圈内的感应电动势：（1）导体中通以直流电流I ，线圈以线速度v 从左向右移动；（2）导体中通以电流t I i m ωsin =，线圈不动；（3）导体中通以电流t I i m ωsin =，线圈以线速度v 从左向右移动。

1．8 在图1-3所示的磁路中，两个线圈都接在直流电源上，已知1I 、2I 、1N 、2N ，回答下列问题：（1）总磁动势F 是多少？（2）若2I 反向，总磁动势F 又是多少？（3）电流方向仍如图所示，若在a 、b 出切开形成一空气隙δ，总磁动势F 是多少？此时铁心磁压降大还是空气隙磁压降大？（4）在铁心截面积均匀和不计漏磁的情况下，比较（3）中铁心和气隙中B 、H 的大小。

（5）比较（1）和（3）中两种情况下铁心中的B 、H 的大小。

一、填空题（共20分）
1、电机是以（ 电磁感应 ）原理进行能量转换的机械，发电机吸收机械能输出（ 电 ）能；而电动机吸收（ 电 ）输出（ 机械 ）能。

2、直流电机的可逆性是指直流电机既可以作为（ 发电 ）机也可以作为（ 电动 ）机的运行特性。

3、在电机理论中，应用右手定则判断导体中（ 感应电动势 ）方向；应用左手定则判断载流导体（ 受力 ）方向。

4、直流电动机的额定效率是（ 输出功率 ）与（ 输入功率 ）的比值，其数学表达式是（ ）。

5、电力变压器一次侧绕组和二次侧绕组极性同时为正的一端称为（ 同名端 ）。

6、按照惯例规定变压器中电磁量的方向，一次侧按（ 电动机 ）惯例规定，二次侧按（ 发电机 ）惯例规定。

7、在异步电动机机械过载倍数是（ 最大转矩 ）和（ 额定转矩 ）比值；对应最大转矩的转差率称为（ 临界 ）转差率。

东北大学继续教育学院 ___电机拖动_B___试卷(开) 座位号:。