东北大学17秋学期《直流自动控制系统》在线作业3答案
东大14秋学期《控制系统 Simulink 仿真》在线作业3答案
?
正确答案：B
10.悬浮Scope模块的使用方法有几种
A. 1
B. 2
C. 3
D. 4
?
正确答案：B
二,判断题
1. S-函数仿真流程为，不论初始化是否结束，在每一个仿真步长（time step）内完成一次求解，如此反复，形成一个仿真循环，直至仿真结束。
A.错误
B.正确
?
正确答案：A
2.对于系统模型中相同的模块，Simlink会对其进行自动编号
A.错误
B.正确
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正确答案：B
3. Simlink中不包含专用模块库
A.错误
B.正确
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正确答案：A
4.系统的数学模型按照输入和输出关系可分为确定性模型和随机性模型
A.错误
B.正确
?
正确答案：B
5.使用命令[t,x,y1,y2,…,yn]=sim(model,timespan,options,ut);当timespan写成[tStart OutputTimes tFinal]的形式时，tStart、OutputTimes、tFinal必须按照升序排列。
A. myoptions=simset(’AbsTol’,’2e-5’);
B. myoptions=simset(’ZeroCross’,’off’);
C. myoptions=simset(’MaxStep’,’1/500’);
D. myoptions=simset(’Solver’,’ode45’);
A.错误
B.正确
?
正确答案：B
6.多项式在matlab中表示为向量形式，可用matlab中的多项式函数求多项式的根，多项式乘积等
17秋学期《大学英语(一)》在线作业3满分答案
17秋学期《大学英语(一)》在线作业3试卷总分:100 得分:100一、单选题1. The boss asked her to take ________ of the office for a few days while he was away.A. chargeB. dutyC. taskD. hand正确答案:A2.The film __________ for ten minutes when we got to the cinema.A. had already been onB. had already begunC. have already been onD. have already begun正确答案:A3.Will there be a strong wind ____ the north ______ the Huanghe River ?A. to... ofB. to... offC. at... ofD. on… off正确答案:A4.He was _____ a gold cup in acknowledgement of his creative achievements for the development of the companyA. awardedB. awardC. rewardedD. reward正确答案:A5.Did it snow _______ last night ?A. heavyB. heavilyC. quickD. fast正确答案:B6.He failed the exam because he didn’t have time(足够的时间) to prepare.A. rightB. spareC. adequateD. own正确答案:C7.They worked hard to _____their small business into a large one.A.transformB.transitionC.transitD.transport正确答案:A8. It is easy for a horse to _____ at the sound of guns.A. frightenB. surpriseC. horrifyD. panic满分：2 分正确答案:D9.Fish and chips _______ the most popular take- away food in England.A. areB. isC. wereD. was满分：2 分正确答案:B10.-- Excuse me, ____________ to the nearest bookshop, please?-- Go straight and take the second turning on the left.A. where the way isB. which the way isC. where is the wayD. which is the way满分：2 分正确答案:D11. Peter may ________ with this, but I don't really care.A. agreeB. disagreeC. differD. dislike满分：2 分正确答案:B12.Do you usually go to school _____ foot?A. onB. inC. atD. by满分：2 分正确答案:A13. Tokyo has ______ twice in the 20th century after the destruction of the earthquake and the World War II.A. been foundedB. foundedC. been rebuiltD. rebuilt满分：2 分正确答案:C14. _______ my mother ________ my sister watches TV plays these days.A. Either, norB. Both,andC. Neither,orD. Neither, nor满分：2 分正确答案:D15. Don’t take everything in the book for _____.A. grantedB. grantingC. grantsD. grant满分：2 分正确答案:A16.-- I' m going to school now, Mum, Bye!-- Just a minute. It's cold outside._________ your coat, please.A. Put onB. Take offC. Put upD. Take down满分：2 分正确答案:A17. The food _______ my hometown is quite different ______that there.A. in ，likeB.to, fromC. from,toD. in, from满分：2 分正确答案:D18. I have seen that this method had been_____by many people.A. appliedB. demandedC. ownedD. disagreed满分：2 分正确答案:A19.-- Is Mr Smith really very ill? --________. He's in hospital.A. I don't think soB. No, he isn'tC. I hope soD. I'm afraid so满分：2 分正确答案:D20. We supply every_____ for traveling.A. requisitionB. requirementC. requisiteD. request满分：2 分正确答案:C21. __your system so the software(软件) will always keep new.A. UpdateB. ChangeC. DeleteD. Destroy满分：2 分正确答案:A22.--Excuse me, where's the post office ?--Sorry, I don't know.--______.A. It doesn't matterB.All rightC. Thank you all the sameD. Don't worry满分：2 分正确答案:C23.--Can I help you? --Yes. I bought this computer here yesterday,but it ______ now.A. didn't workB. won't workC. can’t workD. doesn't work满分：2 分正确答案:D24. The milk has _____ overnightA. been souredB. souringC. been souringD. soured满分：2 分正确答案:D25. He learned how to use sign language to ________ with deaf customers.A. contactB.talkC. connectD. communicate满分：2 分正确答案:D二、阅读理解 (共 4 道试题,共 20 分)1.There have been many great inventions or things that changed the way we live. The first great invention was the one that is still very important today——the wheel. This made it easier to carry heavy things and to travel long distance.For hundreds of years after that there were few inventions that as much effect as the wheel. Then in the early 1800s the world started to change. There was little unknown land left in the world. People didn’t have to explore much any more. They began to work instead to make life better.In the second half of the 19th century many great inventions were made. Among them were the camera, the light and the radio. These all play a big part in our daily life today.The first part of the 20th century saw more great inventions. The helicopter in 1909, movies with sound in 1926, the computer in 1928, jet planes in 1930. This was also a time when a new material was first made. Nylon came out in 1935. It changed the kind of clothes people wore.The middle part of the 20th century brought new ways to help people get over diseases. They worked very well. They made people healthier and allowed them to live longer. By the 1960s most people could expect to live to be at least 60.By this time most people in developed countries had a very good life. Of course new inventions continued to be made. But man now had a desire to explore again. The earth was known to man but the stars were not. Man began looking for ways to go into space. Russia made the first step. Then United States took a step. Since then other countries, including China and Japan, have made their own steps into space.In 1969 man took his biggest step away from earth. Americans first walked on the moon. This is certainly just a beginning, though. New inventions will some day allow us to do things we have never yet dreamed of.1). This passage talks mainly aboutA.why cars were very importantB.when light was inventedC.how inventions affect people’s daily lifeD.which country made the first step into space满分：1 分2). According to the passage man didn’t have a desire to explore a lot .A. at the beginning of 1800sB. in the 1960sC. since the 1900sD. from the 1800s to 1960s满分：1 分3). In the 1800s, people began to work in order to makeA. explorationsB. their life betterC. discoveriesD.a trip to space满分：1 分4). Nylon came out of five years later than .A. radioB. cameraC. jet planesD.movies满分：1 分5). People can live longer lives because that help cure diseases have worked very well.A.doctorsB. new waysC. medicinesD.new hospitals满分：1 分正确答案:1).C2).A3).B4).C5).B2.Happy Time ParkLocationwest of the cityGetting thereNo.16 busOpening hours8:30-16:00 on weekdays,8:00-18:00 on Saturday and SundayAttractions1. Plant Garden: thousands of kinds of plants to see2. Sports Center: ball games, rock climbing, swimming and many other fun games to enjoyFacilitiesparking places, public toilets, public telephones, barbecue places, medical care station and shopping centre at your service1). The park is in the ______ of the city.A. northB. eastC.west满分：1 分2). You can take a ______ bus to get to the park.A. No.16B. No.6C. No.4满分：1 分3). There is ______ in the park.A. a zooB. a cinemaC.a plant garden满分：1 分4). If you visit the park on Wednesday, you must leave the park ______.A.before six o’clock in the afternoonB.between 16:00 and 18:00C.before four o’clock in the afternoon满分：1 分5). Which of the following is TRUE according to the advertisement?A.You can do sports in the park except swimming.B.If you feel ill or get hurt in the park, you can find doctors for help there.C. You can have a barbecue in the park if you buy something in the shopping centre.满分：1 分正确答案:1).C2).A3).C4).C5).B3.Paper is one of the most important products ever invented by man. The invention of paper meant that more people could be educated because more books could be printed. Paper provided an important way to communicate with knowledge.Paper was first made in China about 2,000 years ago. In Egypt and the West, paper was not very commonly used before the year 1400. Paper was not made in southern Europe until about the year 1100. After that, the foresty countries of Canada, Sweden, Norway, Finland, and the United States became the most important in paper-making. Today Finland makes the best paper in the world. And it has the biggest paper industry in the world.When we think of paper, we think of newspapers, books, letters, envelopes, and writing paper. So paper plays an important role in our lives.Paper is very good for keeping you warm. Houses are often insulated(隔热)with paper. You perhaps see homeless men sleep on a large number of newspapers. They are insulating themselves from the cold. In Finland, in winter it is sometimes 40 degrees below zero. The farmers wear paper boots in the snow. Nothing could be warmer.1). What did the invention of paper mean? It meant _________.A. more people could be educatedB.more books could be printedC. paper is one of the most important productsD. Paper was invented by man.满分：1 分2). When was paper made in southern Europe?A. Before 1100.B.After 1400.C. After 1100.D.Before 1400满分：1 分3). Which country makes the best paper?A. Norway.B.CanadaC. The United States.D.Finland.满分：1 分4). What’s the meaning of the sentence “Nothing could be warmer.”?A. Books are warmer.B.Newspapers are warmer.C. Paper is the warmest.D.Houses are the warmest.满分：1 分5). What’s the main idea of the passage?A. The invention of paper.B.The best paperC. The paper-makingD.The uses of paper.满分：1 分正确答案:1).A2).C3).D4).C5).D4.Of course you don’t want to be sick in your vacation. So what can you do while traveling? There are three things you should remember: relax, sleep and eat well.A vacation is a time for relaxing, but very often it is not. Think about what you do when you are a tourist. There are so many places to visit: shops, parks, churches and temples ( 寺庙). You may spend most of the days walking around these places. This can be very tiring. Do not ask your body to do too much. A tired body means a weak body. A weak body gets sick easily. So sit down for a few hours in a nice place. In good weather, look for a quiet park bench.Sleep is also important. If you want to stay healthy, you need to get enough sleep. Your hotel room may be noisy, or the bed may be too hard. Or you may want to stay out late at night. Then you should plan to sleep for an hour during the day. The extra hour can make a big difference.Finally, if you want to stay healthy, you must eat well. That means eating the right kinds of food. Your body needs fresh fruit, vegetables, mean, milk and cheese. So, remember this: if you want to enjoy your vacation, take good care of yourself. Give your body some rest. Get enough sleep and eat healthy food.1). You should ____ while traveling.A. eat wellB. walk all the timeC. do shoppingD. ask your body to do a lot.满分：1 分2). Traveling is usually ____.A. easyB. noisyC. tiringD. dangerous满分：1 分3). You must ___ to enjoy your traveling.A. visit parksB. stay healthyC. go to churches and templesD.sit down for a few hours满分：1 分4). The underlined word “ extra” means ___ here.A. one moreB. more than oneC. usualD. different满分：1 分5). The text tells us ____- in traveling.A. how to restB. what places to visitC. how to relax and sleepD. . how to take good care of ourselves满分：1 分正确答案:1).A2).C3).B4).A5).D三、完型填空 (共 2 道试题,共 30 分)1.The computer plays an important part in our everyday life. It is one of the great __1__ in the world in the __2__ century. It works for us not only at home, in the offices, in big shops, __3__ at schools. Today it is used __4__ many ways. It really __5__ the world large wealth and happiness.The first computer in the world was __6__ Enid. It was built in America in 1946. It was __7__ and heavy. __8__ it was born, it has been developing very fast. Until now it has gone __9__ four periods and changed a lot. There’re many kinds of computers. Computers are getting smaller and smaller and computing faster and faster. It becomes more and more __10__.The computer can do most of the things __11__ the people. It can help us to __12__ about the real world more quickly, to learn __13__ we want to learn and to think __14__ ourselves. __15__ a student in the twenty-first century, you must work hard at it.1).A. inventionsB. discoveriesC. robotsD. inventors满分：1 分2).A. twenty-firstB. twentiesC.twelfthD. twentieth满分：1 分3).A. alsoB. but alsoC. tooD. either满分：1 分4).A.inB.tooC.byD.over满分：1 分5).A.takesB.helpsC.getsD. brings满分：1 分6).A.foundB.inventedC.calledD.bought满分：1 分7).A. easyB. smallC. largeD. light满分：1 分8).A. ForB. UntilC. WhenD. Since满分：1 分9).A. byB. acrossC. throughD. against满分：1 分10).A. seriousB. harmfulC. dangerousD. helpful满分：1 分11).A. forB. toC. atD. with满分：1 分12).A. setB. tellC. knowD. talk满分：1 分13).A. whatB. thatC. whichD. who满分：1 分14).A. ofB. aboutC. outD. for满分：1 分15).A. ForB. BeC. AsD. To满分：1 分正确答案:1).A2).D3).B4).A5).D6).C7).C8).D9).C10).D11).A12).C13).A14).D15).C2.Suppose you are going to Boston, and you 1 the city before. If someone 2 youabout the interesting places in the city, you __3 to get some ideas of what you will see, but don’t have a 4__ idea of where these places are or of how to find 5 . However, 6__ someone has a map of the city and 7 you the main roads and buildings, you may say, “ Oh, now I see . I can find my way with 8__ trouble at all ”. Working in math is somewhat like trying to find your way 9 a new city. Perhaps the words may tell you some information and you have 10 it, but you can’t see any clear road 11 the answers.Maybe you 12 a kind of map of the main roads in maths 13__ you find your way. Explore what lies in maths, and 14 to find the main roads. They will 15 you to the answer. If you can find the “map”, the maths problems will be easily worked out.1).A. are going to visitB. once visitedC. have never visitedD. have ever visit满分：1 分2).A. answersB. showsC. meetsD. tells满分：1 分3).A. beginB. likeC. learnD. refuse满分：1 分4).A. cleverB. clearC. strangeD. wrong满分：1 分5).A. someoneB.BostonC. themD. it满分：1 分6).A. ifB. thoughC. whetehrD. since满分：1 分7).A. helpsB. givesC. passesD. shows满分：1 分8).A. notB. noC. someD. much满分：1 分9).A. ofB. toC. inD. around满分：1 分10).A. thought overB. heard aboutC. written downD. talked with满分：1 分11).A. withB. forC. ofD. to满分：1 分12).A. need to haveB. don't needC. needn'tD. in need of满分：1 分13).A. helpB. to helpC. helpsD. help with满分：1 分14).A. try your bestB. take your placeC. look upD. walk on满分：1 分15).A. keepB. sendC. leadD. ask满分：1 分正确答案:1).C2).D3).A4).B5).C6).A7).D8).B9).B10).A11).D12).A13).B14).A15).C。
东大17秋学期《电工电子技术及应用》在线作业3 免费答案
17秋18春《电工电子技术及应用》在线作业3一、单选题（共 8 道试题，共 40 分。
）1.一个电压源20V和一个电流源5A串联，其等效电路为 ( )。
A 电压源20VB 电流源5AC 其它A.B.C.D.正确答案：B2.如果5欧姆电阻的电流i=l4.l4Sin(l000t)安培，电流i和电压u为关联方向。
则电阻电压的有效值为 ( )伏A 50B 70.7C 其它A.B.C.D.正确答案：A3.一阶RL串联电路中，R为10欧姆，L初始电流为0A，换路后外加电压为10V，则电感电压的稳态值为( )V。
A 0B 10C 其它A.B.C.D.正确答案：A4.如果5欧姆电阻的电流i=l4.l4Sin(l000t)安培，电流i和电压u为关联方向。
则电阻电压的角频率为( )rad/s，A 159.2B 1000C 其它A.B.C.D.正确答案：B5.一阶RC串联电路中，R为100欧姆，电容初始电压为0V，换路后外加电压为10V，则电容的初始电流为( )A。
A 0B 0.1C 其它A.B.C.D.正确答案：B6.一阶RL串联电路中，R为10欧姆，电感初始电流为0A，换路后外加电压为10V，则电感的初始电压为( )A。
A 10B 0C 其它A.B.C.D.正确答案：A7.对称星形三相电路的线电流和相电流有效值( )。
A 相同B 不相同C 其它A.B.C.D.正确答案：A8.一个电流为6A的电流源和2欧姆电阻并联，可等效为一个电压源和电阻串联的电路。
其中电压和电阻分别为( )。
A 3V和2欧姆B 12V和2欧姆C 其它A.B.C.D.正确答案：B17秋18春《电工电子技术及应用》在线作业3二、单选题（共 12 道试题，共 60 分。
）1.1000微法电容两端的电流i为正弦波，其有效值为2安培，角频率为1000rad/s，当电感两端电压u与电流i方向关联时u有效值为( )伏A 2000B 2C 其它A.B.C.D.正确答案：B2.当一个30欧姆的电阻和一个40欧姆的容抗串联，其等效复阻抗Z的阻抗角为 ( )度A 36.9B -53.1C 其它A.B.C.D.正确答案：B3.三角形连结的对称三相电路，线电压和相电压的有效值( )。
东大17春学期《高层建筑结构设计》在线作业3
17秋东北大学东大17春学期《高层建筑结构设计》在线作业3一、单选题（共10 道试题，共50 分。
）1. 已经计算完毕的框架结构，后来又加上一些剪力墙，是否更安全可靠（）。
A. 不安全B. 更安全C. 下部楼层的框架可能不安全D. 顶部楼层的框架可能不安全正确答案：2. 在常用的钢筋混凝土高层结构体系中，抗侧力刚度最好的是（）。
A. 框架结构B. 剪力墙结构C. 框架——剪力墙结构D. 筒体结构正确答案：3. 房屋的顶层、结构转换层、平面复杂或开洞过大的楼层楼面结构，采用下列（）符合《高层规程》的规定A. 应采用装配整体式楼面结构B. 可采用装配整体式楼面结构C. 应采用现浇楼面结构D. 应优先采用现浇楼面结构正确答案：4. 在框架——剪力墙结构体系中，框架和剪力墙协同工作的特点是（）。
A. 框架和剪力墙按侧向刚度分担水平力B. 剪力墙承受全部水平力C. 剪力墙承受80%的水平力，框架承受20%的水平力D. 底部剪力墙承受绝大部分水平剪力，对框架提供侧向支承；顶部则反过来，剪力墙对框架作用与水平荷载方向相同的水平力正确答案：5. 高层建筑结构在计算内力时，对楼面活荷载的考虑，下列（）是正确的。
A. 应根据活荷载大小区别对待B. 不做最不利布置C. 应按最不利分布情况D. 标准层多时不考虑不利布置正确答案：6. 二级抗震设计的剪力墙墙肢轴压比限值为（）。
A. 0.9B. 0.8C. 0.7D. 0.6正确答案：7. 筒中筒结构设计，下列（）要求符合《高层规程》规定。
A. 高宽比宜大于3，高度不宜低于60mB. 高宽比可大于3，高度宜大于60mC. 高宽比应大于3，高度应大于60mD. 高宽比可大于4，高度不宜低于30m正确答案：8. 设防烈度为8度的现浇高层框架——剪力墙结构横向剪力墙的间距，下列（）符合规定要求。
A. ≤4B，并且≤50mB. ≤3B，并且≤40mC. ≤2.5B，并且≤30mD. ≤2B，并且≤30m正确答案：9. 高层剪力墙结构剪力墙的地步加强范围，下列（）符合规定。
东北大学17秋学期《无机化学》在线作业3答案
正确答案：B3.(1)溶解度表明了溶液中溶质和溶剂的相对含量。A.错误B.正确
正确答案：A4.(9)锌、铁是人体必需的微量元素，摄入越多越有利于健康。A.错误B.正确
正确答案：A5.(4)金属中导电性最好的是铜。A.错误B.正确
东北大学17秋学期《无机化学》在线作业3
一、单选题1、C2、B3、B4、D5、A
一、单选题（共10道试题，共50分。）V1.(19)下列电子构型的原子中，处于激发态的是（A1s22s2B1s22s22p1C1s22s22p53s1D1s22s22p63s2A.B.C.D.
正确答案：C2.(2)在原电池中，正极上发生的是（A氧化B还原C置换D分解）。）反应。A.B.C.D.
正确答案：A9.(9)铁原子（Z＝26）在基态下未成对的电子数是（A0B2C3D4A.B.C.D.
正确答案：D10.）。）。(4)在含有I－离子的酸性溶液中，加入含Fe3＋的溶液时，产生（AFeI2BFeI3CFe(OH)3DFe2＋＋I2）。A.B.C.D.
正确答案：D
二、判断题（共10道试题，共50分。）V1.(10)若某反应由几个基元反应所组成，则总反应的速率由基元反应中最慢的一步控制，该基元反应的级数也就是总反应的级数A.错误B.正确
正确答案：D5.(10)已知：Kaq(HAc)＝1.8×10－5，Kaq(HCN)＝4.9×10－10，Kbq(NH3)＝1.8×10－5，浓度均为0.10mol·L-1的NaCl，NH4Cl，NaAc，NaCN水溶液中，OH－浓度由大到小排列的顺序是（）。ANaCN>NaAc>NaCl>NH4ClBNaCl>NH4Cl>NaAc>NaCNCNaCl>NaAc>NH4Cl>NaCNDNaAc>NaCN>NH4Cl>NaClA.B.C.D.
东北大学17秋学期《冶金工程计算机控制与仿真》在线作业2
东北大学17秋学期《冶金工程计算机控制与仿真》在线作业2一、单选题1、C2、D3、B4、C5、D一、单选题（共 6 道试题，共 60 分。
）V 1. 下述名词中，（）不是过渡过程的品质指标。
A. 最大偏差B. 余差C. 偏差D. 过渡时间正确答案：C2. 对某PI控制系统，为了防止积分饱和，采取以下措施，问哪一条是不起作用的？A. 采用高低值阻幅器B. 采用调节器外部积分反馈法C. 采用PI-P调节器D. 采用PI-D调节器正确答案：D3. 下面关于补偿导线说法不正确的有（）。
A. 补偿导线与对应的热电偶在0～100℃ 的温度范围内有相同的热电特性B. 补偿导线无极性C. 不同的热电偶用的补偿导线也不同D. 热电偶测温时使用补偿导线是为了将冷端延伸到温度比较恒定的地方正确答案：B4. 多变量系统变量配对时，应选择相对增益__________的调节变量和被调量。
A. 大于1B. 小于零C. 等于或接近于1正确答案：C5.对于如图所示的锅炉液位的双冲量控制系统，有如下说法：①这是一个前馈与反馈相结合的控制系统②这是一个串级控制系统③加入前馈控制的目的是克服由于蒸汽负荷突然变化而造成的虚假液位④双冲量是指蒸汽流量和给水流量⑤阀门的作用形式为气关阀这些说法中，（）是正确的。
A.①②③B. ②③④C. ①④⑤D. ①③⑤正确答案：D6.温度控制系统如图所示，当物料为温度过高时易结焦或分解的介质、调节介质为过热蒸汽时，。
东大18秋学期《工程制图》在线作业3
------------------------------------------------------------------------------------------------------------------------------ (单选题) 1: 剖切符号应用（）绘制。
A: 细实线B: 粗实线C: 点画线D: 虚线正确答案：(单选题) 2: 水平投影平行OX轴，侧面投影平行OZ轴，正面投影反映实长和实形，则此直线为（）。
A: 水平线B: 正平线C: 侧平线正确答案：(单选题) 3: 正面投影平行OX轴，侧面投影平行OYW轴，水平投影反映实长和实形，则此直线为（）。
A: 水平线B: 正平线C: 侧平线正确答案：(单选题) 4: 与三个投影面倾斜的直线，称为（）。
A: 平行线B: 垂直线C: 一般位置直线正确答案：(单选题) 5: 在三面投影体系中，Z坐标值大小反映两点的（）位置。
A: 前后B: 左右C: 上下正确答案：(单选题) 6: （）的正面投影反映平面的实形；水平投影、侧面投影均积聚为一条直线段，且分别平行于OX、OZ轴。
A: 正平面B: 水平面C: 侧平面正确答案：(单选题) 7: （）的水平投影反映平面的实形；正面投影、侧面投影均积聚为一条直线段，且分别平行于OX、OYW轴。
A: 正平面B: 水平面C: 侧平面正确答案：(单选题) 8: 可见轮廓线应用（）绘制。
A: 细实线B: 粗实线------------------------------------------------------------------------------------------------------------------------------ C: 点画线D: 虚线正确答案：(单选题) 9: ()的正面投影积聚为一斜直线，与OX、OZ轴的夹角，反映平面对H、W面对真实倾角；水平投影和侧面投影都是缩小到类似形。
东大14秋学期《计算机控制系统》在线作业3答案
?
正确答案：B
11.执行器的作用使接受计算机发出的控制信号。（）
A.错误
B.正确
?
正确答案：B
12.传感器无输入时，每隔一定时间其输出值偏离原始值最大偏差与满量程的百分比为零漂。（）
A.错误
B.正确
?
正确答案：B
13.计算机控制系统信号变换过程要经过连续数字信号转换模拟信号输入给执行机构。（）
?
正确答案：C
3.一阶系统的单位阶跃响应需要过渡过程时间等于_____。
A.
T
B.
2T
C.
3T
D.
4T
?
正确答案：A
4.保持是_____反向变换？
A.编码
B.量化
C.采样
D.保持
?
正确答案：C
5. 1.下列哪个不是计算机控制系统控制过程的步骤？
A.数据采集
B. .数据转换
C. .计算机控制量
D.输出控制信号
?
正确答案：B
二,判断题
1.长线传输干扰的抑制主要是消除线路中的波发射。（）
A.错误
B.正确
?
正确答案：A
2.控制管理级与过程控制级为操作站、控制站、现场仪表三层结构模式。（）
A.错误
B.正确
?
正确答案：B
3.二阶系统的单位脉脉冲响应是一减幅正弦振荡函数，其稳态值为1.（）
A.错误
B.正确
?
正确答案：B
A.错误
B.正确
?
正确答案：A
14.电磁场干扰的实质是互感性耦合干扰。（）
A.错误
B.正确
?
正确答案：B
15.计算机控制系统通常在离散控制系统框架下进行研究，其输入量与输出量关系可用微分方程描述。（）
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东北大学17秋学期《直流自动控制系统》在线作业3
一、单选题1、B2、B3、C4、B5、A
一、单选题（共10道试题，共50分。
）V
1.普通逻辑无环流（既无推b又无准备）可逆调速系统中换向时待工作组投入工作时，电动机处于（）状态。
A.回馈制动
B.反接制动
C.能耗制动
D.自由停车
正确答案：B
2.在调磁调速下，电动机保持恒定的参数是()。
A.电枢电流
B.输出功率
C.电枢电压
D.激磁电流
正确答案：B
3.下列交流异步电动机的调速方法中，应用最广的是_______。
A.降电压调速
B.变极对数调速
C.变压变频调速
D.转子串电阻调速
正确答案：C
4.限止电流冲击的最简单方法是采用_____。
A.转速微分负反馈
B.电流截止负反馈
C.电压负反馈
D.带电流正反馈的电压负反馈
正确答案：B
5.对于调磁的直流电动机来说，一般情况下，基速以上采用的调速方式是()。
A.弱磁调速
B.恒转矩调速
C.调压调速
D.反电动势调速
正确答案：A。