北京科技大学2013年《853电路理论与自动控制原理》考研专业课真题试卷

合集下载

北京科技大学2013年《850电路理论与数字技术》考研专业课真题试卷

图6
-2-
二、数字技术部分（共 60 分）
7、（10 分）化简下列逻辑函数为最简与或式。
Y AC ACD B B C
8、（15 分）用 3 线-8 线译码器 74LS138（如图 7 所示）和若干与非门设计 1 位二进制全加器电路，并按要求完成下列各小题。（1）用逻辑变量 A、B、C、D、E 分别表示全加器的被加数、加数、来自低位的进位、和以及向高位的进位，试列出全加器的真值表。（2）写出该全加器各输出变量的最小项与或表达式。（3）画出用 3 线-8 线译码器 74LS138 和若干与非门实现该全加器的逻辑电路图（必须画在答题纸上）。
图7 9、（15 分）JK 触发器组成的异步计数电路如图 8 所示，按要求完成下列各小题。（1）分别写出各触发器的时钟方程和状态方程及电路的输出方程。（2）画出电路的状态转换图，说明电路能否自启动（必须画在答题纸上）。（3）说明电路为几进制计数器，其状态编码属于何种码制。
图8 10、（10 分）电路如图 9 所示，74LS160 为中规模集成同步十进制加法计数器，其功能表如表 1 所示，此电路构成几进制计数器？请画出电路完整的状态转换图。
一、电路理论部分（共 90 分）
1、（15 分）电路如图 1 所示，计算 2 所示，计算电压 U。
图2 3、（15 分）电路如图 3 所示，负载电阻 RL 可变，计算：（1）RL 为何值时，它可以取得最大功率；（2）求此最大功率。
图3
-1-
4、（15 分）电路如图 4 所示，开关 S 闭合前电路已稳定，在 t=0 时开关 S 闭合，试计算：（1）电感电流的初始值 iL(0+)。（2）采用三要素法求解图中电压 u(t)。

北京科技大学853电路分析基础历年考研真题专业课考试试题

目　录
2014年北京科技大学853电路分析基础考研真题
2013年北京科技大学850电路理论与数字技术考研真题2012年北京科技大学815电路及数字电子技术考研真题2011年北京科技大学815电路及数字电子技术考研真题2010年北京科技大学815电路及数字电子技术考研真题2009年北京科技大学815电路及数字电子技术考研真题2008年北京科技大学815电路及数字电子技术考研真题2007年北京科技大学415电路及数字电子技术考研真题2006年北京科技大学415电路及数字电子技术考研真题2005年北京科技大学电路及数字电子技术考研真题2004年北京科技大学415电路及数字电子技术考研真题2003年北京科技大学415电路及数字电子技术考研真题2002年北京科技大学电路及数字电子技术考研真题2001年北京科技大学电路及数字电子技术考研真题
2014年北京科技大学853电路分析基础考研
真题。

北京科技大学单独考试英语 2013年硕士研究生考研真题

北京科技大学2013年硕士学位研究生入学考试试题============================================================================================================= 试题编号： 240 试题名称单独考试英语（共 14 页）适用专业：全校各专业单独考试考生说明：所有答案必须写在答题纸上，做在试题或草稿纸上无效。

============================================================================================================= Part I: Vocabulary (20 minutes, 10 points, 0.5 point each)Section ADirections: There are 10 incomplete sentences in this part. For each sentence there are four choices marked A., B., C. and D. Choose the ONE that best completes the sentence and mark your answer on the ANSWER SHEET.1. Psychological studies show that some people are quick-tempered .A．at heart B. on purpose C. in person D. by nature2. If a person talks about his weak points，his listener is expected to say something in the way of .A．assures B. encouragement C. persuasion D. confirmation3. He was high school and college instructors trying to teach him how to think to use the "scientific method" rather than teaching him the structure of the subject.A．put up with B. given way to C. fallen back on D. fed up with4. The film was 'Cezanne'，a 50-minute on the painter and his work.A．mediation B. medication C. meditation D. metrication5. You can't work for six hours without a single break ―it's impossible!A. continuouslyB. continuallyC. frequentlyD. often6. The humour of the play was too for the young audience and they rarely laughed.A. detailedB. feebleC. subtleD. slender7. It is well known that a child does not reach emotional security a good many years after physical maturity.A．for B. during C. as long as D. until8. Man's understanding and his mastering of matter and energy his claim to superiority；provide him with the basis for enriching and deepening human experience.A．designate B. deserve C. justify D. illustrate9. They to investigate the circumstances at the time of the accident and it is now too late to prove anything.A．ignored B. intended C. neglected D. disregarded10.People that vertical flight transports would carry millions of passengers as do theairliners of today.A. convincedB. anticipatedC. resolvedD. assuredSection BDirections: In this section, there are ten sentences with one word or phrase underlined each. Choose one of the four choices marked A, B, C and D that best keeps the meaning of the sentence if it is substituted for the underlined word.11. She didn't openly attack the plan，but her opposition was implicit in her failure to say anythingin support of it.A．explicit B. obvious C. decisive D. underlying12. We will shortly be arriving in King's Cross Station. May I remind all passengers to take theirluggage with them.A．immediately B. directly C. soon D. later13. Act according to what the laws prescribe and you'll have no trouble.A．say B. impose C. decide D. define14.The matter has been gone into very thoroughly, and we find there are no grounds for theallegations.A. investigatedB. explainedC. describedD. stated15. The test comprises four sections，namely，Listening，Reading，Vocabulary and Compositionwith a time limit for each.A．consists of B. involves C. indicates D. composes of16. Being infamous for his dishonesty in business matters，the man had few friends.A．fresh B. immediate C. notorious D. famous17. Some people persist in the practice of some very old customs or traditions just because theyenjoy doing so.A．endure B. support C. stick to D. continue in18. Many local authorities realize the need to make provisions for elderly people in their housingprogrammes.A．assistance B. rooms C. conditions D. supplies19. He was very careful in whatever he did lest something unfavourable might be written into hisrecord.A．if only B. for fear that C. unless D. otherwise20. The story was given a prominent position in the front page.A．obvious B. clear C. apparent D. noticeablePart II Cloze Test(20 minutes, 10 points, 1 point each)Directions: For each blank in the following passage, choose the best answer from the choices given below. Mark your answer on the Answer Sheet by drawing with a pencil a short bar across the corresponding letter in the brackets.It is difficult to imagine what life would be like without memory. The meanings of thousands of everyday perceptions, the bases ____21____ the decisions we make, and the roots of our habits and skills are to be ____22____ in our past experience, which are brought into the present ____23____ memory.Memory can be defined as the capacity to keep ____24____ available for later use. It includes not only "remembering" things like arithmetic or historical facts, but also any change inthe way an animal typically behaves. Memory is ____25____ when a rat gives up eating grain because he has sniffed something suspicious in the grain pile. Memory is also involved when a six-year-ole child learns to swing a baseball bat.Memory ____26____ not only in humans and animals but also in some physical objects and machines. Computers, for example, contain devices for storing data for later use. It is interesting to compare the memory-storage capacity of a computer ____27____ that of a human being. The instant-access memory of a large computer may hold up to 100 000 "words"--ready for ____28____ use. An average American teenager probably recognizes the meanings of about 100 000 words of English. However, this is but a fraction of the total ____29____ of information which the teenager has stored. Consider, for example, the number of facts and places that the teenager can recognize on sight. The use of words is the basis of the advanced problem-solving intelligence of human beings. A large part of a person's memory is in terms of words and ____30____ of words.21. A. of B. to C. for D. on22. A. keep B. found C. sought D. stored23. A. by B. from C. with D. in24. A. experiences B. bases C. observations D. information25. A. called B. taken C. involved D. included26. A. exists B. appears C. affects D. seems27. A. to B. with C. against D. for28. A. progressive B. instructive C. instant D. protective29. A. deal B. number C. mount D. amount30. A. combinations B. connections C. co-ordinations D. collectionsPart III Reading Comprehension (60 minutes, 40 points)Section A (30 points, 1.5 points each)Directions:In this part there are four passages followed by questions or unfinished statements, each with four suggested answers. Choose the one you think is the best answer and mark your choice on the Answer Sheet.Passage OneQuestions 31-35 are based on the following passage:The need for solar electricity is clear. It is safe, ecologically sound, efficient, continuouslyavailable, and it has no moving parts. The basic problem with the use of solar photovoltaic devices is economics, but until recently very little progress had been made toward the development of low-cost photovoltaic devices. The larger part of research funding has been devoted to study of single-crystal silicon solar cells, despite the evidence, including that of the leading manufacturers of crystalline silicon, that the technique holds little promise. The reason for this pattern is understandable and historical. Crystalline silicon is the active element in the very successful semiconductor industry, and virtually all of the solid state devices contain silicon transistors and diodes. Crystalline silicon, however, is particularly unsuitable to terrestrial solar cells.Crystalline silicon solar cells work well and are successfully used in the space program, where cost is not an issue. While single-crystal silicon has been proven in extraterrestrial use with efficiencies as high as 18 percent, and other more expensive and scare materials such as gallium arsenide can have even higher efficiencies, costs must be reduced by a factor of more than 100 to make them practical for commercial use. Besides the fact that the starting crystalline silicon is expensive, 95 percent of it is wasted and does not appear in the final device. Recently, there have been some imaginative attempts to make polycrystalline and ribbon silicon, which are lower in cost than high-quality single crystals; but to date the efficiencies of these apparently lower-cost arrays have been unacceptably small. Moreover, these materials are cheaper only because of the introduction of disordering in crystalline semiconductors, and disorder degrades the efficiency of crystalline solar cells.This dilemma can be avoided by preparing completely disordered or amorphous materials. Amorphous materials have disordered atomic structure as compared to crystalline materials: that is, they have only short-range order rather than the long-range periodicity of crystals. The advantages of amorphous solar cells are impressive. Whereas crystals can be grown as wafers about four inches in diameter, amorphous materials can be grown over large areas in a single process. Whereas crystalline silicon must be made 200 microns thick to absorb a sufficient amount of sunlight for efficient energy conversion, only 1 micron of the proper amorphous materials is necessary. Crystalline silicon solar cells cost in excess of $100 per square foot, but amorphous films can be created at a cost of about 50 per square foot.Although many scientists were aware of the very low cost of amorphous solar cells, they felt that they could never be manufactured with the efficiencies necessary to contribute significantly to the demand for electric power. This was based on a misconception about the feature which determines efficiency. For example, it is not the conductivity of the materials in the dark which is relevant, but only the photoconductivity, that is, the conductivity in the presence of sunlight. Already, solar cells with efficiencies well above 6 percent have been developed using amorphous materials, and further research will doubtless find even less costly amorphous materials withhigher efficiencies.31. What's the major obstacle to the wide use of solar electricity?A. Solar photovoltaic devices are too expensive.B. Little research has been done to study solar cells.C. Solar electricity is neither safe nor efficient.D. The leading manufacturers only produce crystalline silicon for extraterrestrial use.32. According to the passage, which of the following is NOT true of crystalline silicon?A. It can be found in nearly all solid state devices in the form of transistors and diodes.B. It is successfully used in the space program with high efficiency.C. It is unsuitable to terrestrial solar cells as it is limited to military use.D. Its use is not economical with a high percentage wasted.33. The author's attitude toward attempts to make polycrystalline and ribbon silicon can best bedescribed as ________.A. enthusiasmB. optimismC. doubtD. disapproval34. In Para. 3, the author focuses primarily on ________.A. presenting two types of materials for solar cellsB. discussing the advantages of amorphous materials over crystalline siliconC. pointing out the feasibility of using amorphous materials in extraterrestrial programsD. outlining the specific reasons why a problem in solar cells has not yet been solved35. Which of the following was true of many scientists?A. They felt amorphous materials were too costly.B. They were doubtful whether they could develop amorphous solar cells with higherefficiencies.C. They realized that it was the conductivity in the presence of sunlight that was relevant toefficiency.D. They were optimistic about the future use of amorphous materials with higher efficiencies.Passage TwoQuestions 36-40 are based on the following passage:My hands are sweating, my face is breaking out, my heart is pounding, my temper is short. Am I having a heart attack? Am I having a nervous breakdown? No! Final exams are coming up and I am experiencing test anxiety.Is test anxiety destructive? Can we make test anxiety work for us? The answer to both of these questions is yes. Test anxiety often interferes with student performance but this same test anxiety, if channeled correctly, can help improve performance.The good side of test anxiety is that it causes us to attend to the problem. It motivates us to want to study and prepare for the exam. Without this catalyst we might never be concerned about preparing for a test. Thus, a little anxiousness shouldn't worry you. Those of us who speak publicly know that a few butterflies in the stomach just prior to a speech means that we will probably do a good job, that we will focus on our speech and block out extraneous material.However, when stress interferes with your ability to concentrate, then it has reached the destructive state. In order to lessen the destructive elements of test anxiety, the approach should be to develop improved confidence and knowledge. These two factors go hand in hand. As your knowledge of the course material increases, your confidence in your ability to succeed will increase. As your confidence increases, your anxiety will go down, allowing your knowledge to come through more efficiently. The way you prepare for a test can reduce anxiety during the test.36. Which of the following is NOT a symptom of test anxiety?A. Hands are sweating.B. Face is breaking out.C. Heart is pounding.D. Heart attack.37. According to the passage, test anxiety can benefit us in all of the following ways except thatit________.A. motivates us to make good preparation for the testB. helps us to concentrateC. can ensure us a good score in the testD. can help improve performance if channeled correctly38. Which of the following statement is TRUE about the relationship between test anxiety and confidence and knowledge?A. As your knowledge of the course material increases, your confidence in your ability tosucceed will increase.B. As your confidence increases, your anxiety will go down.C. As your anxiety increases, your knowledge will increase more efficiently.D. Both A) and B)39. What might be discussed in the following part of the article?A. Some specific recommendations for reducing test anxietyB. The negative effects of anxiety on students who take testsC. only poor students have the problem of test anxietyD. only if you are hard-working, you will not have the problem of test anxiety40. What is the best title for the passage?A. How to prepare tests?B. Knowledge and preparation for testsC. Test Anxiety: Friend or Foe?D. Is test anxiety destructive?Passage ThreeQuestions 41-45 are based on the following passage:Like her white friends Eleanor Roosevelt and Aubrey Williams, Mary Bethune believed in the fundamental commitment of the New Deal to assist the black American's struggle and in the need for blacks to assume responsibilities to help win that struggle. Unlike those of her white liberal associates, however, Bethune's ideas had evolved out of a long experience as a "race leader." Founder of a small black college in Florida, she had become widely known by 1935 as an organizer of black women's groups and as a civil and political rights activist. Deeply religious, certain of her own capabilities, she held a relatively uncluttered view of what she felt were the New Deal's and her own people's obligations to the cause of racial justice. Unafraid to speak her mind to powerful whites, including the President, or to differing black factions, she combined faith in the ultimate willingness of whites to discard their prejudice and bigotry with a strong sense of racial pride and commitment to Negro self-help.More than her liberal white friends, Bethune argued for a strong and direct black voice in initiating and shaping government policy. She pursued this in her conversations with PresidentRoosevelt, in numerous memoranda to Aubrey Williams, and in her administrative work as head of the National Youth Administration's Office of Negro Affairs. With the assistance of Williams, she was successful in having blacks selected to NY A posts at the national, state, and local levels. But she also wanted a black presence throughout the federal government. At the beginning of the war she joined other black leaders in demanding appointments to the Selective Service Board and to the Department of the Army; and she was instrumental in 1941 in securing Earl Dickerson's membership on the Fair Employment Practices Committee. By 1944, she was still making appeals for black representation "all public programs, federal, state, and local," and "in policy-making posts as well as rank and file jobs."Though recognizing the weakness in the Roosevelt administration's response to Negro needs, Mary Bethune remained in essence a black partisan champion of the New Deal during the 1930s and 1940s. Her strong advocacy of administration policies and programs was predicated on a number of factors: her assessment of the low status of black Americans during the Depression; her faith in the willingness of some liberal whites to work for the inclusion of blacks in the government's reform and recovery measures; her conviction that only massive federal aid could elevate the Negro economically; and her belief that the thirties and forties were producing a more self-aware and self-assured black population. Like a number of her white friends in government, Bethune assumed that the preservation of democracy and black people's "full integration into the benefits and the responsibilities" of American life were inextricably tied together. She was convinced that, with the help of a friendly government, a militant, aggressive "New Negro "would emerge out of the devastation of depression and war, a "New Negro" who would "save America from itself," who would lead America toward the full realization of its democratic ideas.41. What was the common belief held by Mary Bethune and her white friends?A. For blacks who wanted to achieve equality there was a long way to go.B. It was the responsibility of both government and blacks to fight for racial justice.C. Racial prejudice was too deep-rooted to overcome.D. It was the cause of blacks to struggle for equal rights.42. Which of the following was true of Mary Bethune?A. She graduated from a small black college in Florida.B. She founded a black women's group in 1935.C. She was active in civil and political rights movement.D. She was unwilling to express her views directly to powerful whites.43. Bethune talked to President Roosevelt and wrote countless letters to Aubrey William in orderto ________.A. have blacks selected to important government postsB. let them hear direct black voiceC. be appointed to the Department of the ArmyD. appeal to them to support her campaign44. The word "instrumental" (Line 8, Para. 2) is closest in meaning to ________.A. insistentB. inspirationalC. importantD. intelligent45. What was Mary Bethune's response when she realized the Roosevelt administration didn't takestrong actions to improve the Blacks' conditions?A. She lost hope in the New Deal and began to attack it.B. She continued to support the New Deal so as to win its help in return.C. She looked forward to a more friendly white government.D. She believed only a militant, aggressive black government could save blacks.Passage FourQuestions 46-50 are based on the following passage:The exclusive emphasis on economics is yielding to an appreciation of politics. After all, before free market can thrive you need political stability. Technology is still seen as a powerful tool, but one that can have harmful as well as beneficial consequences (as Osama bin Laden has brutally shown). Most important, the global trading system is becoming more democratic, with countries like India, China and Brazil demanding a voice in the shape of trade negotiations. This too could be for the best. If a few concessions and delays mean that the free-trade system will have greater legitimacy in the developing world, it is a price well worth paying.Even September 11 could be even more beneficial. In the past four months the world has seen what American political leadership and power can do when it is ambitious, energetic and internationally minded. It is time for American economic leadership to be similarly active and visionary. Treasury Secretary Paul O'Neill's speech at the forum was an interesting beginning. O'Neill talked about changing the loans-and-grants system to developing countries to help them help themselves. He talked about insisting on internal legal and political reforms. He pointed out that foreign aid rarely works. His critiques of the current system was sharp, but anyone cancriticize. The point is to fix things. He should take this opportunity to present a series of broad American initiatives that would broaden and deepen globalization.Washington should lead the developed world by responding to the legitimate demands of the developing world on trade-that means agriculture and anti-dumping. Hormats argues for a reform of the major international economic groups and institutions. A new system of effective foreign aid could have massive economic and political benefits for the whole world.In the wake of World War II, the Truman administration set up the global economic institutions that have secured and steered the world economy ever since. Throughout the cold war, America pushed for free trade as part of an overall strategy to combat communism and shore up the free world. Making globalization work better and for more people is not simply smart economics. It is a vital part of a new national-security strategy for America.46. Which of the following is more emphasized now after September 11?A. Domestic economy.B. Politics.C. National Security.D. Global unity in fighting terrorism.47. What does Hormats argue for?A. The developing countries have to help themselves.B. A new system of effective foreign aids will work well.C. The USA pushed and will push free trade world widely to combat communism.D. The foreign aids rarely work.48. What makes the author's opinion different from O'Neill's?A. The author thought that O'Neill's talk was not to the point.B. The author didn't like the talker personally.C. O'Neill should have presented what to do to improve the economic globalization.D. The author thought what O'Neill said was precise, but not workable.49. What does the author intend to say through the last paragraph?A. The Americans should follow Truman's global economic policy.B. The author suggests that the USA should have done more.C. The USA should pursue to combat the communism in economic competition.D. The Americans may live in luxurious and quiet surroundings under the conditions of theglobalization.50. The topic that best fits the passage is ___________.A. The National Security Strategy of the USAB. The Globalization of Economy and National Security Strategy of the USAC. The World Economic ForumD. International Economic GlobalizationSection B (10 points, 2 points each)Directions: Read the following passage and complete the sentences with the information from the passage in NO MORE THAN 10 words for each sentence.Starting to write is like setting out on a sea voyage. You experience certain queasiness until you get your sea legs. To get your sea legs in writing, you need a firm grasp on what you hope to accomplish in the work you plan to write. In other words, you need to discover your purpose before you can begin to write effectively. As self-evident as finding your purpose would seem to be, it is easily overlooked. Although writing is a major part of my professional life, I find I often set out to write without thinking about my purpose at all. But then, when I become queasy, I say to myself, "Just what is it I really want to do here? What do I really want to say?" In answering these questions I usually manage to get the project launched; and so the technique of asking yourself such questions is one I heartily recommend to you.Answering "What do I really want to do?" requires deciding exactly what response you want your words and ideas to evoke in those who will read them. For instance, you might want a business letter to move your correspondent to offer a job interview, or an essay to dazzle your history professor into giving you an "A". More often your aim will be less personal: you want your reader to understand your subject and to find your approach to it acceptable.In all your planning, writing, and revising, your first consideration should be how your words will affect your readers. To find out, put yourself in their place-be your own reader-and think how the words would affect you. Convincing and satisfying your readers is the whole point of writing effectively.Answering the question "What do I really want to say?" pinpoints the matter you want your readers to understand, the idea you want to convince them is valid or worth their while. In expository writing, discovering what you want to say involves finding your thesis and the means to support it. The thesis is the heart of expository writing.Although you may find the term "expository writing" unfamiliar, it describes the most familiar of all writing. It is the sort of writing found in textbooks and other works of nonfiction, in magazines, in many newspaper articles, the type of writing you are called upon to produce for college exams and business reports, the workaday, useful writing that makes the world's intellectual wheels to go around. With expository writing you expound, explain, and set forth information and ideas. It is distinguished from narrative writing, the other major type of prose, by its organization. Narrative writing, which tells a story, is structured chronologically: "and then this happened, and then that happened." Expository writing, which makes a statement, is organized to start its point, its thesis, most effectively.The essence of what you mean to get across in a given work is called the thesis. It summarizes what your reader should come to believe. It is also the organizational focus of expository writing. Conventionally, some statement of the thesis is placed toward the end of the introductory portion of a piece of expository prose and/ or somewhere in the concluding segment. Sometimes the thesis is not stated in so many words, and occasionally it is only implied; but there can be no good expository writing without it. Without a thesis, expository writing is, literally, pointless.51. What is often overlooked by people when they start to write?52. According to the passage, what is your first consideration in your writing process?53. What is the most important part of expository writing?54. What is the difference between expository writing and narrative writing?55. What is the thesis in expository writing?Part IV Translation (40 minutes, 20 points )Section ADirections:Translate the following passage from English into Chinese.The Olympic Games are a display of international goodwill. The ceremonies, with their emphasis upon both nationalism and internationalism, are a thrilling sight to see. At the start, the king or president of the country in which the Olympic Games are being held is presented. The national anthem of his country is sung. Then follows a parade of all the contestants, each bearing his country's flag and shield. This march is accompanied by a fanfare of trumpets. When the Olympic flag is raised, guns fire a salute. Doves, symbols of peace, are released. Finally the sacred fire is lit. The Olympic flame is set alight by a torch that has been carried by relay runners all the way from。

电子科技大学839自动控制原理_2013年真题及答案

电⼦科技⼤学839⾃动控制原理_2013年真题及答案2013年试题1. (共15分) 某控制系统状态⽅程为X AX ?=,其中，A 是22?常数⽅阵。

当1(0)1X ??=??-??时，22t t e X e --??=??-??当2(0)1X ??=??-??时，2t t e X e --??=??-??，试求该系统的状态转移矩阵()t φ2. (共20分) 某负反馈系统结构框图如图1所⽰，其中1()G s 环节的单位阶跃响应为58(1)5t e -- 1) 当()201(),()0r t t f t =?=时，试求系统响应的超调量，调节时间及输出稳态值。

2) 当()201(),()1()r t t f t t =?=时，试求系统的稳态误差。

其中，系统误差()E s 如图1所⽰。

图13. (共15分) 某负反馈系统的特征⽅程为2(10)(1)0s s K s +++=1) 试绘制该系统的根轨迹图。

2) 试确定使系统暂态响应分别为衰减振荡及单调变化时K 的取值范围。

4. (共15分) 某受控对象()G s 的单位脉冲响应为0.54()(12)t tg t K ee --=+-，将()G s 构成单位负反馈系统，如图2所⽰。

1) 试绘制该单位负反馈系统的开环幅相曲线(Nyquist 曲线) 2) 试求出该系统处于临界稳定时的开环增益和振荡频率值。

(r图25. (共20分) 已知某单位负反馈最⼩相位系统，其被控对象0()G s 的开环对数幅频特性0()L ω和串联校正装置()c G s 的对数幅频特性()c L ω如图3所⽰。

1) 试写出校正后系统的开环传递函数0()()()c G s G s G s =。

2) 试分析图中所采⽤的校正装置的类型，并讨论校正装置对系统相⾓裕度γ、剪切频率c ω及抗⾼频⼲扰等指标的影响。

图36. (共15分) 某离散控制系统如图4所⽰，T 为采样周期，0.25T s = 1) 求使得系统稳定的K 的取值范围。

北科大强军计划基础课和专业课真题(2013年)

北科大强军计划基础课和专业课真题（2013年）一、简答题(8分/题，共40分)1.超点阵；2.玻璃化转变温度；3.伪共晶；4.脱溶；5.二次再结晶。

二、图1是立方ZnS结构示意图，回答以下问题（共20分）：1.Zn2+的负离子配位数是多少？2.Zn2+占据以S2-密排结构的间隙位置，写出Zn2+占有位置的坐标；3.计算ZnS结构的晶格常数(已知Zn2+和S2-的离子半径分别为0.06nm和0.18nm)；4.计算ZnS结构的致密度。

三、图2是在同一滑移面上三组相互平行的相距为d的直位错，它们的柏氏矢量b的模相等，箭头指向是柏氏矢量b 和位错线t的方向。

问每组的位错之间是相互吸引还是相互排斥，为什么？（共15分）图2三组相互平行的直位错及其柏氏矢量（第三题图）四、示意画出图3所示的A-B体系中各相在T1、T2、T3和T4温度时的Gibbs自由焓-成分曲线。

(共10分)五、图4为某三元合金系在T1和T2温度下的等温截面。

若T1>T2,确定此合金系中存在哪种类型的三相平衡反应？说明判断理由，并写出三相反应式。

(共10分)六、由材料A和B组成双层平板，A板厚度为L，B板厚度为2L，如图5所示。

扩散组元在A板一侧表面的浓度为c=c0(常数)，在B板一侧表面的浓度一直保持为c=0。

假设：扩散组元不与A和B形成新相；在A和B中扩散系数均为常数，分别是D1和D2；扩散组元在A/B界面浓度保持连续；A和B相互之间不扩散。

求扩散在稳态时的扩散流量。

(共15分)七、什么是动态回复?什么是动态再结晶?分别画出在相同温度时高、低应变速率下动态回复和动态再结晶的真应变—真应力曲线示意图，并给出简单解释。

(共10分)八、常温下单相合金塑性变形有哪些主要方式，说明拉伸变形后相应的显微组织形貌特征。

(共10分)操作系统【考查目标】1.掌握操作系统的基本概念、基本原理和基本功能，理解操作系统的整体运行过程。

2.掌握操作系统进程、内存、文件和I/O管理的策略、算法、机制以及相互关系。

2013年北京科技大学普通物理考研真题

2013年北京科技大学普通物理考研真题北京科技大学2013年硕士学位研究生入学考试试题试题编号：612 试题名称：普通物理____________适用专业：物理学_____________________________________________________________ 说明：所有答案必须写在答题纸上，做在试题或草稿纸上无效。

一、选择题(每题3分，共30分)1、以下五种运动形式中，N保持不变的运动是(A)单摆的运动. (B)匀速率圆周运动.(C)行星的椭圆轨道运动. (D)抛体运动.(E)圆锥摆运动.2、人造地球卫星绕地球作椭圆轨道运动，卫星轨道近地点和远地点分别为yl和氏用厶和&分别表示卫星对地心的角动量及其动能的瞬时值，则应有(A)LAL B、EXA^EiCB・(B) LFL B、EMEd・(C) LFL B、E KA/E ES•3、一质量为加的滑块，由静止开始沿着1/4圆弧形光滑的木槽滑下.设木槽的质量也是皿槽的圆半径为凡放在光滑水平地而上, 如图所示.则滑块离开槽时的速度是(A)J5冠・(B)、灰?・(C) 2、灰?[ ](D) \癒. (E) * 屈•4、均匀细棒创可绕通过其一端0而与棒垂直的水平固怎光滑轴转动, 如图所示.今使棒从水平位置由静止开始自由下落，在棒摆动到竖直位宜的过程中，下述说法哪一种是正确的？(A)角速度从小到大，角加速度从大到小.(C) 角速度从大到小，角加速度从大到小.(D) 角速度从大到小，角加速度从小到大.5、有一半径为斤的水平圆转台，可绕通过英中心的竖直固龙光滑轴转动.转动惯量为/ 开始时转台以匀角速度。

转动，此时有一质量为m 的人站在转台中心.随后人沿半径向外跑去，当人到达转台边缘时，转台的角速度为(B) 角速度从小到大, 角加速度从小到大.(j+m)R 2(D) %・6、在空气平行板电容器中，平行地插上一块各向同性均匀电介质板，如图所示•当电容器充电后•若忽略边缘效应，则电介质中的场强E 与空气中的场强EO 相比较，应有(A) E 〉两者方向相同・(B) E=0 两者方向相同・(C) E 〈两者方向相同・(D) E 〈0两者方向相反.7、已知一厚度为〃的无限大带电导体平板，两表而上的电荷密度均匀分布，而电荷密度均为则板外侧的电场强度的大小为J+ mR 2 (C(C)2久[ ]8、如图所示，一无限长载流导线通有电流II,长为b通有电流12的导线AB与长直载流导线垂直，其A端距长直导线的距离为a,则导线AB 受到的安培力大小为:9、一块铜板放在磁感应强度正在增大的磁场中时，铜板中出现涡流(感应电流)，则涡流将(A) 加速铜板中磁场的增加.(B) 减缓铜板中磁场的增加.(C) 对磁场不起作用.(D) 使铜板中磁场反向. [ ]10、在圆柱形空间内有一磁感强度为鸟的均匀磁场，如图所示.D 的大小以速率dS/dr 变化.在磁场中有乂万两点，苴间可放直导线曲和弯曲的导线AB,则(A)电动势只在曲直导线中产生.(B) 电动势只在M 弯导线中产生・(C) 电动势在直导线和弯导线中都产生，且两者大小相等.(D) 直导线中的电动势小于弯导线中的电动势・二、填空题(每题3分，共30分)1、飞轮作加速转动时，轮边缘上一点的运动学方程为S= 0.1 F (SI).飞轮半径为2m.当此点的速率D=30∏√s 时，其切向加速度的大小为 ___________________ ，法向加速度的大小为___________________ O2、某质点在力F=(4+5.Y )7 (SD 的作用下沿X 轴作直线运动，在从x=0移动到f=10 In 的过程中，力尸所做的功为 ______________ O3、如图所示，质量为m 的子惮以水平速度％射入静止的木块并陷入% ——木块内，设子弹入射过程中木块M 不反弹，则墙壁对木块的冲量 ⑷2πa (C) 2TUI a (B)(D) 2π GI二___________________________ 》4、一圆盘绕一固泄轴转动，初始角速度为Qr转动惯量为几设它所受的阻力矩与转动角速度成正比，即M =-kω（W为正的常数）。

北京科技大学《自动控制原理》复习

ci
s ir1 pi
ci
lim (s
s pi
pi )G(s)
i r 1,, n
c1i
1
d i1
(i
1)!
lim
s p1
dt
i1
(s
p1)r G(s)
i 1, , r.
p1
•
x
1
0
1 p1
0
p r 1
0
x
1
u
1
pn 1
y c11 c1r cr1 cn x
电位器
G(s) K
测速电机 G(s) Ks
电加热炉单容水槽双容水槽
G(s) K Ts 1
G(s) K Ts 1
G(s) K e s (有纯延迟)
Ts 1
(也可有延迟，略) K
G(s) T1T2s2 (T1 T2 )s 1
• 比例环节
• 一阶惯性环节 • 积分环节 • 微分环节、一阶微分环节 • 二阶振荡环节 • 二阶微分环节 • 延迟/时滞环节
5、高阶系统的时域分析
主导极点：在高阶系统中某一极点或一对共轭复数极点距虚轴的距离是其它极点距虚轴距离的1/5或更小，并且附近没有闭环零点，称该极点（对）为该高阶系统的主导极点。
①用主导极点来估计高阶系统的性能指标 ②导出高阶系统单位阶跃响应的近似表达式
偶极子：指相距很近的一对零、极点。
6、线性系统状态方程的解状态转移矩阵性质：
sa
(s a)2 2
控制系统的数学描述
定义：单输入单输出线性定常动态对象的传递函数G(S)是零初值下
该对象的输出量的拉普拉斯变换Y(S)与输入量的拉普拉斯变换U(S)

北京科技大学计算机组成原理考研真题答案附后

北京科技大学869计算机组成原理考研真题答案附后最新资料，WORD格式，可编辑修改！目录1．北京科技大学计算机组成原理历年考研真题...........................................2014年北京科技大学869计算机组成原理考研真题 ...................................2013年北京科技大学869计算机组成原理考研真题 ................................... 2．江苏大学计算机组成原理历年考研真题...............................................2014年江苏大学850计算机组成原理考研真题 .......................................2013年江苏大学850计算机组成原理考研真题 ....................................... 3．杭州电子科技大学计算机组成原理历年考研真题.......................................2014年杭州电子科技大学852计算机组成原理考研真题 ...............................2013年杭州电子科技大学852计算机组成原理考研真题 ...............................2012年杭州电子科技大学852计算机组成原理考研真题 ...............................2011年杭州电子科技大学852计算机组成原理考研真题 ...............................4．广东工业大学计算机组成原理历年考研真题...........................................2014年广东工业大学832计算机组成原理考研真题 ...................................2013年广东工业大学832计算机组成原理考研真题 ...................................2012年广东工业大学832计算机组成原理考研真题 ...................................2011年广东工业大学832计算机组成原理考研真题 ................................... 5．沈阳航空航天大学计算机组成原理历年考研真题.......................................2014年沈阳航空航天大学818计算机组成原理考研真题 ...............................2013年沈阳航空航天大学818计算机组成原理考研真题 ............................... 6．沈阳工业大学计算机组成原理历年考研真题...........................................2014年沈阳工业大学838计算机组成原理考研真题 ...................................2013年沈阳工业大学838计算机组成原理考研真题 ................................... 7．其他名校计算机组成原理历年考研真题...............................................2015年华侨大学848计算机组成原理考研真题 ....................................... 说明：精选了17套名校计算机组成原理历年考研真题。

北京科技大学851自动控制原理2013年考研专业课真题试卷

时，
x(t)
=

e−t

0.5
试求当 x(0) =
1
及 u(t) = 1(t) 时，系统的响应 x(t)，并求系统矩阵 A。
北京科技大学 2013 年硕士学位研究生入学考试试题
=============================================================================================================
试题编号： 853 试题名称：电路理论与自动控制原理（共 4 页）
1、（15 分）试说明图 1 中 Y 形连接电阻和∆形连接电阻之间等效变换的条件，并
推导等效变换的公式。
图1 2、（15 分）在图 2 所示电路中，已知R1 = 5Ω，R2 = 5Ω，R3 = 10Ω，Rx = 5Ω，E =12V，检流计G的电阻 RG =10Ω。（1）试用诺顿定理求检流计G中的电流IG；（2）试求当Rx为何值时，检流计G中的电流IG等于 0。
分）已知线性系统的状态方程为：
x
=Αx
+

0 1

u
，其中
A
为一个
2×2
的常数矩阵。在 u(t) = 0 的情况下，当初始状态 x(0)分别取
1
e−2t
1）
x(0)
=

0

时，
x(t)
=

0

0
e−t − e−2t
2）
x(0)
=

1

功率表W1、W2的读数；（3）试求三相电路总的有功功率。

北京科技大学安全原理考研试题.docx

北京科技大学安全原理考研试题一、解释下列名词（统考生：每题 3 分，任选10 小题回答，共30 分；单考生：每题 4 分，共40 分）1. 安全科学四要素共2. 职业安全健康管理体系共3. 安全336 260384. 危害021-5. 职业病kaoyangj6. 劳动保护彰武7. 安全目标管理33623 0378. “三不放过”原则辅导9. 安全信息021-10. 危险因素正门对面11. 有害因素20009212. 风险评价3362 3039二、简述题（统考生单考生：每题10分，共70分）2000921. 简述轨迹交叉论的基本思想336 260382. 简述安全生产五要素”课3. 简述海因里希因果连锁理论kaoyangj4. 简述第一类伤害同济大学四平路5. 简述变化失误理论kaoyangj6. 简述与强制原理中的安全第一原则研7. 简述安全人机学的主要内容112 室三、论述题（统考生：每题15 分，共30 分；单考生：每题20 分，共40 分）48 号1. 试述道化学公司的火灾爆炸指数方法的评价程序2. 试述OSHMS 标准的运行模式四、计算题（20 分，单考生不答此题）有一事故树如下图，试求其最小割集、最小径集及其结构重要度。

一、解释下列名词（统考生：每题3分，任选10小题回答，共30分；单考生：每题4分，共40分）1. 安全科学四要素［解析］安全科学四要素包括人、物、人与物、信息。

2. 职业安全健康管理体系［解析］职业安全健康管理体系简称OSHMS，是指为建立职业安全健康方针和目标并实现这些目标所制定的一系列相互联系或相互作用的要素管理体系。

3. 安全［解析］安全是指免受不可接受的风险的伤害。

4. 危害［解析］危害是指可能带来人员伤害、疾病、财产损失或作业环境破坏的根源或状态。

5. 职业病［解析］职业病是指企业、事业单位和个体经济组织的劳动者在职业活动中，因接触粉尘、放射性物质和其他有毒、有害物质等因素而引起的疾病。