2011年西工大研究生入学试题
2004--2011年西工大《材料科学基础》硕士研究生入学试题+3份模拟题
04年西北工业大学硕士研究生入学试题一、简答题:(共40分,每小题8分)1、请简述间隙固溶体、间隙相、间隙化合物的异同点?2、请简述影响扩散的主要因素有哪些。
3、临界晶核的物理意义是什么?形成临界晶核的充分条件是什么?4、有哪些因素影响形成非晶态金属?为什么?5、合金强化途径有哪些?各有什么特点?二、计算、作图题:(共60分,每小题12分)1、求]111[和]120[两晶向所决定的晶面,并绘图表示出来。
2、氧化镁(MgO )具有NaCl 型结构,即具有O 2-离子的面心立方结构。
问:(1) 若其离子半径+2Mg r =0.066nm ,-2O r =0.140nm ,则其原子堆积密度为多少?(2) 如果+2Mg r /-2O r=0.41,则原子堆积密度是否改变?3、已知液态纯镍在1.013×105 Pa (1大气压),过冷度为319 K 时发生均匀形核,设临界晶核半径为1nm ,纯镍熔点为1726 K ,熔化热ΔH m =18075J/mol ,摩尔体积V s =6.6cm 3/mol ,试计算纯镍的液-固界面能和临界形核功。
4、图示为Pb-Sn-Bi 相图投影图。
问:(1)写出合金Q (w Bi =0.7,w Sn =0.2)凝固过程及室温组织;(2)计算合金室温下组织组成物的相对含量。
5、有一钢丝(直径为1mm )包复一层铜(总直径为2mm )。
若已知钢的屈服强度σst =280MPa ,弹性模量E st =205GPa ,铜的σCu =140MPa ,弹性模量E Cu =110GPa 。
问:(1)如果该复合材料受到拉力,何种材料先屈服?(2)在不发生塑性变形的情况下,该材料能承受的最大拉伸载荷是多少?(3)该复合材料的弹性模量为多少?三、综合分析题:(共50分,每小题25分)1、某面心立方晶体的可动滑移系为]101[ )111(、。
(1) 请指出引起滑移的单位位错的柏氏矢量;(2) 若滑移由刃位错引起,试指出位错线的方向;(3) 请指出在(2)的情况下,位错线的运动方向;(4) 假设在该滑移系上作用一大小为0.7MPa 的切应力,试计算单位刃位错线受力的大小和方向(取点阵常数为a =0.2nm )。
西工大2011级数理统计考试题
Test Paper for Research Design and Statistics for Applied LinguisticsDec. 2011Name: Student No.:1.The following table lists the prices of certain randomly selected college textbooks instatistics, psychology, economics, and business.以下图标列出的是某个随机抽取的大学统计学,心理学,经济学,商学的课本价格ing the 5% significance level, test the null hypothesis that the mean prices ofcollege textbooks in statistics, psychology, economics, and business are all equal.使用5%的显著水平,来检测当这些大学统计学、心理学、经济学、和商学课本的平均价格都相等的零假设。
2.The English department at a college has hired a new instructor to teach the compositioncourse to first-year students. The department head is co ncerned that the new instructor’sgrading practices might not be consistent with those of the professor (let us call himProfessor A) who taught this course previously. She randomly selects 10 essays writtenby students for this class and makes two copies of each essay. She asks Professor A andthis instructor (working independently) to assign a numerical grade to each of the 10essays. The results are shown in the following table.学院的英语教研室为一年级学生信聘任了一名讲师教作文,主任怕这名讲师的打分习惯跟原来教这门课的教授们不一致,于是她随机选了该班学生写的10篇作文并把每一篇作文复印两份,分别交给教授A和该讲师。
西北工业大学 研究生考试真题+习题 自动控制原理
2002年硕士研究生入学考试试题试题名称:自动控制原理 试题编号:541说明:所有试题一律写在答题纸上 共 3 页 第 3 页221-=K , 1)(=s H2002年硕士研究生入学考试试题试题名称:自动控制原理试题编号:541说明:所有试题一律写在答题纸上共 3 页第 3 页2002年硕士研究生入学考试试题试题名称:自动控制原理试题编号:541说明:所有试题一律写在答题纸上共 3 页第 3 页试题名称:自动控制原理 试题编号: 427试题名称:自动控制原理 试题编号: 427试题名称:自动控制原理 试题编号: 427西北工业大学2004年硕士研究生入学考试试题试题名称:自动控制原理(A 卷) 试题编号: 427 说 明:所有答题一律写在答题纸上 第 1 页 共 3 页1.(25分)已知系统结构图如图1所示(1) 确定使系统稳定的参数t K K ~0的取值范围,并在t K K ~0平面上表示出来;(2) 要求在2)(2t t r =作用下系统的稳态误差0=ss e ,试确定)(s G c 的表达式。
2.(25分)系统结构图如图2所示(1) 绘制当∞→变化时的系统根轨迹(求出渐近线,分离点,与虚轴交点),确定使系统稳定的开环增益=00K K 的取值范围;(2) 若已知闭环系统的一个极点为11-=λ,试确定系统的闭环传递函数。
试题名称:自动控制原理(A 卷) 试题编号: 427 说 明:所有答题一律写在答题纸上 第 2 页 共 3 页3.(25分)某单位反馈的最小相角系统,其开环对数幅频特性如图3所示。
(1) 写出系统开环传递函数)(s G 表达式; (2) 求系统的截止频率c ω和相角裕度γ。
[ 注:振荡环节的谐振频率221ξωω-=n r ,谐振峰值2121ξξ-=r M ]4.(25分)系统结构图如图4所示,被控对象的传递函数为)101.0)(11.0()(0++=s s s Ks G(1) 当1)(=s G c 时,若要求系统的静态误差系数100=v ,试判断系统此时是否稳定;K (2) 令100=K ,为使系统获得大于︒30的相角裕度,采用校正装置 1005.0105.0)(++=s s s G c试验证校正后系统是否满足要求。
西工大-西北工业大学研究生入学试题-有限元
西北工业大学研究生入学试题考试科目:结构有限元分析基础题号:464说明:所有试题一律答在答题纸上共3 页第 1 页1-7题为必做题,8、9两题任选一题1.(本题10分) 在按位移求解的平面有限元法中,(1)应力边界条件及位移边界条件是如何反映的?(2)力的平衡条件是如何满足的?(3) 变形协调条件是如何满足的?2. (本题10分) 下列三种情况,元素的刚度矩阵是否相同? 为什么?(图2所示)图22.(本题10分) 在有限元法中, 等参数单元的主要优点是什么?4. (本题10分) 试写出下列单元的位移函数,并求出其形函数矩阵[]N图4共 3 页 第 2 页5. (本题15分) 图5所示的三结点杆元素ijm ,A 、E 为元素的截面积和材料弹性模量,元素的位移函数为:()2210x a x a a x u ++= 试分析:(1)上述位移函数是否满足收敛准则?(2)求元素的形状函数矩阵[]N ;(3)求元素的几何矩阵[]B ,应力矩阵[]S ;6. (本题10分) 写出图6所示三角形元素各结点(各边结点等间距)的面积坐标值,并利用内插方法找出元素的形状函数(N 1 , N 7 , N 9 , N 10)。
7. (本题15分) 图7所示杆板结构,按下列情况划分,选取元素:(1)结构由10个两结点杆元素和8个三结点三角形板元素集合而成。
(2)结构由5个三结点杆元素和2个六结点三角形板元素集合而成试分析:两种分元素情况下,采用相同的结点编号。
(1)总刚度矩阵大小是否相同?(2)半带宽是否一样?(3)杆板元素间位移是否协调?8. (本题20分) 图8中两个三角形单元组成平行四边形,已知单元①按局部编码m j i ,,的单元刚度矩阵[])1(K , 试求: (1)按结点编号组装形成总体刚度矩阵[]K(2)求出自重作用下等效结点载荷,(三角形面积为Δ,板厚t ,比重ρ)(3)用删行删列法引入边界约束函数,写出最终结构平衡方程。
西北工业大学-硕士研究生入学考试-问答题答案
(6)加工工艺方法带来的误差。 6. 数控编程工艺处理中是如何确定加工用量的?(5 分) 答:切削用量包括切削深度、切削宽度、主轴转速、进给速度等。 切削深度:主要根据机床、工件和刀具的刚度决定。 切削宽度:加工时每相邻两刀之间的距离 L,又称为行距。粗加工切削宽度由刀具、机床、零件 的刚性决定。精加工可根据零件的粗糙度计算确定。要降低表面粗糙度,可缩小行距,但加工效率降 低;因此在保证行距不变的前提下,应选择较大半径的刀具,可明显降低残留高度。 转速的确定:根据实际经验,并配合刀具厂家提供的刀具切削线速度 v (m/min) 查表计算来确定。 进给量 F:根据零件的加工精度、表面光洁度、切削深度、宽度以及刀具和工件材料而选择。 7. 数控机床按同时控制的坐标轴可划分为哪几种类型?并说明其可能完成哪些类型零件的加工?(7 分) 答:两坐标、三坐标、四坐标、五坐标 NC 机床 1)两坐标 NC 机床:可加工二维轮廓零件。 2)三轴联动的 NC 机床:可用于加工曲面类零件。 3)四坐标联动:可加工各种曲面、四轴直纹面叶轮、螺旋类零件和平面内斜孔的壳体类零件。与 三坐标机床相比它的加工范围、精度都得到了提高。 4) 五坐标联动: 理论上可实现空间在不干涉情况下任何复杂结构零件的加工, 如加工曲面变斜角、 各种叶轮、闭式叶盘、带有空间斜孔的复杂壳体类零件。 8. 请简述图像编程的一般过程。 (8 分) 答:零件图纸和设计实体模型CAD 系统造型工艺处理:CAPP、工艺人员规划CAM 系统刀 位轨迹计算刀位验证后置处理加工程序 9. 有如下两句 NC 加工程序: “N10 G1 X-10 Y-10 A-10 C20 F100,N11 G1 X20 Y30 A-110 C120 F100” 当数控机床执行完第 10 句后,执行第 11 句时,请计算数控机床分别在 X、Y 及 A、C 轴上的分进 给速度。 (10 分)
(NEW)西北工业大学机电学院《878机械设计》历年考研真题汇编
目 录2015年西北工业大学878机械设计考研真题(回忆版1)2015年西北工业大学机械设计考研真题(回忆版2)2015年西北工业大学878机械设计考研真题(回忆版3)2014年西北工业大学878机械设计考研真题(回忆版)2013年西北工业大学878机械设计考研真题(回忆版)2012年西北工业大学878机械设计考研真题(回忆版)2011年西北工业大学878机械设计考研真题(回忆版1)2011年西北工业大学878机械设计考研真题(回忆版2)2010年西北工业大学878机械设计考研真题2009年西北工业大学878机械设计考研真题2007年西北工业大学804机械设计考研真题2006年西北工业大学492机械设计考研真题2005年西北工业大学492机械设计考研真题2004年西北工业大学492机械设计考研真题2003年西北工业大学492机械设计考研真题2015年西北工业大学878机械设计考研真题(回忆版1)一、填空题(本题满分30分,每空1分)1.零件的截面形状一定,当截面尺寸增大时,其疲劳极限将随之______。
2.螺栓的放松装置或方法很多,就工作原理来看,可分为______、______破环螺旋副运动关系的放松。
3.普通平键连接工作时,键的主要失效形式为______。
4.过盈连接的承载能力最主要取决于______。
5.带传动的有效拉力决定于______、______、______三个因素。
6.链条的磨损主要发生在______的接触面上。
7.大小齿轮的材料、热处理和加工方法相同,则其弯曲疲劳强度______,接触疲劳强度。
8.蜗杆头数越多,其传动效率______,其自锁性______。
9.液体动压滑动轴承的向心滑动轴承的偏心距,是随着轴颈转速的增大而_____,随着载荷的增大而______。
10.有一滚动轴承的代号为6208/P5,轴孔内径为_______。
11.在载荷不平稳且有较大冲击和振动的情况下,一般宜选用_____联轴器。
2011年全国硕士研究生入学统一考试(含答案)
2011年全国硕士研究生入学统一考试英语(二)试卷Section I Use of EnglishDirections: Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D an ANSWER SHEET 1. (10 points)"The Internet affords anonymity to its users — a boon to privacy and freedom of speech. But that very anonymity is also behind the explosion of cyber crime that has 1 across the Web.Can privacy be preserved 2 bringing a semblance of safety and security to a world that seems increasingly 3 ?Last month, Howard Schmidt, the nation’s cyber czar, offered the Osa ma government a 4 to make the Web a safer place —a ―voluntary identify‖ system that would be the high-tech 5 of a physical key, fingerprint and a photo ID card, all rolled 6 one. The system might use a smart identity card, or a digital credential 7 to a specific computer, and would authenticate users at a range of online services.The idea is to 8 a federation of private online identify systems. Users could 9 which system to join, and only registered users whose identities have been authenticated could navigate those systems. The approach contrasts with one that would require an Internet driver’s license 10 by the government.Google and Microsoft are among companies that already have sign-on‖ systems that make it possible for users to 11 just once but use many different services.12 , the approach would create a ―walled garden‖ in safe ―neighborhoods‖ and bright ―streetlights‖ to establish a sense of a 13 community.Mr. Schmidt described it as a ―voluntary ecosystem‖ in which indivi duals and organizations can complete online transactions with 14 ,trusting the identities of the infrastructure that the transaction runs 15 .'"Still, the administration’s plan has 16 privacy rights activists. Some applaud the approach; others are concerned. It seems clear that such an initiative push toward what would 17 be a license‖ mentality.The plan has also been greeted with 18 by some experts, who worry that the ―voluntaryand identify themselves, in drivers must be licensed to drive on public roads.1.A.swept B. skipped C. walked D. ridden2.A.for B. within C. while D. though3.A.careless B. lawless C. pointless D. helpless4.A.reason B. reminder C. compromise D. proposalrmation B. interference C. entertainment D. equivalent6.A.by B. into C. from D. over7.A.linked B. directed C. chained D. compared8.A.dismiss B. discover C. create D. improve9.A.recall B. suggest C. select D. realize10.A.released B. issued C. distributed D. delivered11.A.carry on B. linger on C. set in D. log in12.A.In vain B. In effect C. In return D. In contrast13.A.trusted B. modernized C. thriving D. competing14.A.caution B. delight C. confidence D. patience15.A.on B. after C. beyond D. across16.A.divided B. disappointed C. protected D. united17.A.frequently B. incidentally C. occasionally D. eventually18.A.skepticism B. tolerance C. indifference D. enthusiasm19.A.manageable B. defendable C. vulnerable D. invisible20.A.invited B. appointed C. allowed D. forcedSection II Reading ComprehensionPart ADirections:Read the following four passages. Answer the questions below each passage by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1. (40 points)Text 1Ruth Simmons joined Goldman Sachs's board as an outside director in January 2000; a year later she became president of Brown University in Rhode Island. For the rest of the decade she apparently juggled both roles (as well as several other directorships) without attracting much criticism. But by the end of 2009 Ms Simmons was under fire from students and alumni for having sat on Goldman's compensation committee; how could she have let those enormous bonus payouts pass unremarked? By February Ms Simmons had left the board. The position was just taking up too much time, she said.Outside directors are supposed to serve as helpful, yet less biased, advisers on a firm's board. Having made their wealth and their reputations elsewhere, they presumably have enough independence to disagree with the chief executive's proposals. Leaders from other fields are frequently in demand: former presidents or Cabinet members, retired CEOs, and yes, university presidents. If the sky, and the share price, is falling, outside directors should be able to give advice based on having weathered their own crises.The researchers used a database that covered more than 10,000 firms and more than 64,000 different directors between 1989 and 2004. Then they simply checked which directors stayed from one proxy statement to the next. The most likely reason for departing a board was age, so the researchers concentrated on those "surprise" disappearances by directors under the age of 70. They found that after a surprise departure, the probability that the company will subsequently have to restate earnings increases by nearly 20%. The likelihood of being named in a federal class-action lawsuit also increases, and the stock is likely to perform worse. The effect tended to be larger for larger firms, although a correlation between them leaving and subsequent bad performance at the firm is suggestive, it does not mean that such directors are always jumping off a sinking ship. Often they "trade up", leaving riskier, smaller firms for larger and more stable firms.But the researchers believe that outside directors have an easier time of avoiding a blow to their reputations if they leave a firm before bad news breaks, even if a review of history shows they were on the board at the time any wrongdoing occurred. Firms who want to keep their outside directors through tough times may have to create incentives, such as increasing pay, says Dr Fahlenbrach.Otherwise outside directors will follow the example of Ms Simmons, once again very popular on campus.21. According to Paragraph 1,Ms Simmons was criticized for .A. gaining excessive profits B .failing to fulfill her dutyC .refusing to make compromises D. leaving the board in tough times22. We learn from Paragraph 2 that outside directors are supposed to be .A. generous investors B .unbiased executivesC .share price forecastersD .independent advisers23. According to the researchers from Ohio University,after an outside director’s Surprisedeparture ,the fire is likely to .A. become more stableB. report increased earningsC .do less well in the stock market D. perform worse in lawsuits24. It can be inferred from the last paragraph that outside directors .A. may stay for the attractive offers form the firm.B. have often had records of wrongdoings in the firm.C. are accustomed to stress-free work in the firm.D. will decline incentives from the firm.25 The author’s attitude toward the role of outside directors is.A permissiveB positiveC scornfulD criticalText 2Whatever happened to the death of newspapers? A year ago the end seemed near. The recession threatened to remove the advertising and readers that had not already fled to the internet. Newspapers like the San Francisco Chronicle were chronicling their own doom. America’s Federal Trade Commission launched a round of talks about how to save newspapers. Should they become charitable corporations? Should the state subsidize them? It will hold another meeting on June 15th. But the discussions now seem out of date.In much of the world there is little sign of crisis. GermA.n and Brazilian papers shrugged off the recession (see article). Even American newspapers, which inhabit the most troubled corner of the global industry, have not only survived but often returned to profit. Not the 20% profit margins that were routine a few years ago, but profit all the same.It has not been much fun. Many papers stayed afloat by pushing journalists overboard. The American Society of News Editors reckons that 13,500 newsroom jobs have gone since 2007. Readers are paying more for slimmer products. Some papers even had the nerve to refuse delivery to distant suburbs. Yet these desperate measures have proved the right ones and, sadly for many journalists, they can be pushed further.Newspapers are becoming more balanced businesses, with a healthier mix of revenues from readers and advertisers. American papers have long been highly unusual in their reliance on ads. Fully 87% of their revenues came from advertising in 2008, according to the OECD. In Japan the proportion is 35%. Not surprisingly, Japanese newspapers are much more stable.The whirlwind that swept through newsrooms harmed everybody, but much of the damage has been concentrated in areas where newspapers are least distinctive. Car and film reviewers have gone. So have science and general business reporters. Foreign bureaus have been savagely pruned. Newspapers are less complete as a result. But completeness is no longer a virtue in the newspaper business. Just look at the fate of Otis Chandler’s creation.26.By saying ―Newspapers like ….their own doom‖(lines 3-4,para,1) the author indicates that newspapers .A .neglected the sign of crisisB .failed to get state subsidiesC .were not charitable corporationsD .were in a desperate situation27.Some newspapers refused delivery to distant suburbs probably because .A .readers threatened to pay lessB .newspapers wanted to reduce costsC .journalists reported little about these areasD .subscribers complained about slimmer products.pared with their American counterparts, Japanese newspaper are much more stable because they .A .have more sources of revenueB .have more balanced newsroomsC .are less dependant on advertisingD .are less affected by readership29.What can be inferred from the last paragraph about the current newspaper business?A .Distinctiveness is an essential feature of newspapers.B .Completeness is to blame for the failure of newspapers.C .Foreign bureaus play a crucial role in the newspapers business.D .Readers have lost their interest in car and firm30.The most appropriate title for this text would beA .American Newspapers: Struggling for SurvivalB .American Newspapers: Gone with the WindC .American Newspapers: A Thriving BusinessD .American Newspapers: A Hopeless StoryText 3We tend to think of the decades immediately following World War II as a time of prosperity and growth, with soldiers returning home by the millions, going off to college on the G.I. Bill and lining up at the marriage bureaus.But when it came to their houses, it was a time of common sense and a belief that less truly be more. During the Depression and the war, Americans had learned to live with less, and that restraint,in combination with the postwar confidence in the future, made small, efficient housing positively stylish.Economic condition was only a stimulus for the trend toward efficient living. The phrase ―less is more‖ was actually first popularized by a German, the architect Ludwig Mies van der Rohe, who like other people associated with the Bauhaus, a school of design, emigrated to the United States before World War II and took up posts at American architecture schools. These designers came to exert enormous influence on the course of American architecture, but none more so than Mies.Mies’s signature phrase means that less decoration, properly organized, has more impact than a lot. Elegance, he believed, did not derive from abundance. Like other modern architects, he employed metal, glass and laminated wood — materials that we take for granted today but that in the 1940s symbolized the future. Mies’s sophisticated presentation ma sked the fact that the spaces he designed were small and efficient, rather than big and often empty.The apartments in the elegant towers Mies built on Chicago’s Lake Shore Drive, for example, were smaller-two-bedroom units under 1,000 square feet —than those in their older neighbors along the city’s Gold Coast. But they were popular because of their airy glass walls, the views they afforded and the elegance of the buildings’ details and proportions, the architectural equivalent of the abstract art so popular at the time.The trend toward ―less‖ was not entirely foreign. In the 1930s Frank Lloyd Wright started building more modest and efficient houses —usually around 1,200 square feet —than the spreading two-story ones he had designed in the 1890s and the early 20th century.The ―Case Study Houses‖ commissioned from talented modern architects by California Arts & Architecture magazine between 1945 and 1962 were yet another homegrown influence on the ―less is more‖ trend. Aesthetic effect came from the land scape, new materials and forthright detailing. In his Case Study House, Ralph Rapson may have mispredicted just how the mechanical revolution would impact everyday life — few American families acquired helicopters, though mosteventually got clothes dryers — but his belief that self-sufficiency was both desirable and inevitable was widely shared.31. The postwar American housing style largely reflected the Americans .A. prosperity an growthB. efficiency and practicalityC. restraint and confidenceD. pride and faithfulness32. Which of the following can be inferred from Paragraph 3 about the Bauhaus?A. It was founded by Ludwig Mies van der Rohe.B. Its designing concept was affected by World War II.C. Most American architects used to be associated with it.D. It had a great influence upon American architecture.33.Mies held that elegance of architectural design .A. was related to large spaceB. was identified with emptinessC. was not reliant on abundant decorationD. was not associated with efficiency34.What is true about the apartments Mies built on Chicago’s Lake Shore Drive?A. They ignored details and proportions.B. They were built with materials popular at that time.C. They were more spacious than neighboring buildings.D. They shared some characteristics of abstract art.35.What can we learn about the design of the ―Case Study Houses‖?A. Mechanical devices were widely used.B. Natural scenes were taken into consideration.C. Details were sacrificed for the overall effect.D. Eco-friendly materials were employed.Text 4Will the European Union make it? The question would have sounded outlandish not long ago. Now even the project’s greatest cheerleaders talk of a continent facing a ―Bermuda triangle‖ of debt, demographic decline and lower growth.As well as those chronic problems, the EU faces an acute crisis in its economic core, the 16 countries that use the single currency. Markets have lost faith that the euro zone’s economies, weaker or stronger, will one day converge thanks to the discipline of sharing a single currency, which denies uncompetitive stragglers the quick fix of devaluation.Yet the debate about how to save Europe’s single currency from disintegration is stuck. It is stuck because the euro zone’s dominant powers, France and Germany, agree on the need for greater harmonisation within the euro zone, but disagree about what to harmonise.Germany thinks the euro must be saved by stricter rules on borrowing, spending and competitiveness, backed by quasi-automatic sanctions for governments that stray. These might include threats to freeze EU funds for poorer regions and EU mega-projects, and even the suspension of a count ry’s voting rights in EU ministerial councils. It insists that economic co-ordination should involve all 27 members of the EU club, among whom there is a small majority for free-market liberalism and economic rigour; in the inner core alone, Germany fears, a small majority favour French dirigisme.A ―southern‖ camp headed by France wants something different: ―European economic government‖ within an inner core of euro-zone members. Translated, that means politicians meddling in monetary policy and a system of redistribution from richer to poorer members, via cheaper borrowing for governments through common Eurobonds or outright fiscal transfers. Finally, figures close to the French government have murmured, euro-zone members should agree to some fiscal and social harmonisation: eg, curbing competition in corporate-tax rates or labour costs.It is too soon to write off the EU. It remains the world’s largest trading block. At its best, the European project is remarkably liberal: built around a single market of 27 rich and poor countries, its internal borders are far more porous to goods, capital and labour than any comparable trading area. It is an ambitious attempt to blunt the sharpest edges of globalisation, and make capitalism benign.36.The EU is faced with to many problems thatA .it has more or less lost faith in marketsB .even its supporters begin to feel concernedC .some of its member countries plan to abandon euroD .it intends to deny the possibility of devaluation37 The debate over the EU’s single currency is stuck because the dominant powersA .are competing for the leading positionB .are busy handling their own crisesC. fail to reach an agreement on harmonisationD .disagree on the steps towards disintegration38 To solve the euro problem ,Germany proposed thatA .EU funds for poor regions be increasedB .stricter regulations be imposedC .only core members be involved in economic co-ordinationD .voting rights of the EU members be guaranteed39 The French proposal of handling the crisis implies thatA. poor countries are more likely to get fundsB .strict monetary policy will be applied to poor countriesC .loans will be readily available to rich countriesD .rich countries will basically control EurobondsA .pessimisticB .desperate C. conceited D. hopefulPart BDirections:You are going to read a list of headings and a text about what parents are supposed to do to guide their children into adulthood. Choose a heading from the list A — G that best fits the meaning of each numbered part of the text (41 — 45). There are two extra headings that you do not need to use. Mark your answers on ANSWER SHEET 1. (10 points)Leading doctors today weigh in on the debate over the government's role in promoting public health by demanding that ministers impose "fat taxes" on unhealthy food and introduce cigarette-style warnings to children about the dangers of a poor diet.The demands follow comments last week by the health secretary, Andrew Lansley, who insisted the government could not force people to make healthy choices and promised to free businesses from public health regulations.But senior medical figures want to stop fast-food outlets opening near schools, restrict advertising of products high in fat, salt or sugar, and limit sponsorship of sports events by fast-food producers such as McDonald's.They argue that government action is necessary to curb Britain's addiction to unhealthy food and help halt spiraling rates of obesity, diabetes and heart disease. Professor Terence Stephenson, president of the Royal College of Paediatrics and Child Health, said that the consumption of unhealthy food should be seen to be just as damaging as smoking or binge drinking."Thirty years ago, it would have been inconceivable to have imagined a ban on smoking in the workplace or in pubs, and yet that is what we have now. Are we willing to be just as courageous in respect of obesity? I would suggest that we should be," said the leader of the UK's children's doctors.Lansley has alarmed health campaigners by suggesting he wants industry rather than government to take the lead. He said that manufacturers of crisps and confectionery could play a central role in the Change4Life campaign, the centrepiece of government efforts to boost healthy eating and fitness. He has also criticised the celebrity chef Jamie Oliver's high-profile attempt toimprove school lunches in England as an example of how "lecturing" people was not the best way to change their behaviour.Stephenson suggested potential restrictions could include banning TV advertisements for foods high in fat, salt or sugar before the 9pm watershed and limiting them on billboards or in cinemas. "If we were really bold, we might even begin to think of high-calorie fast food in the same way as cigarettes – by setting stringent limits on advertising, product placement and sponsorship of sports events," he said.Such a move could affect firms such as McDonald's, which sponsors the youth coaching scheme run by the Football Association. Fast-food chains should also stop offering "inducements" such as toys, cute animals and mobile phone credit to lure young customers, Stephenson said.Professor Dinesh Bhugra, president of the Royal College of Psychiatrists, said: "If children are taught about the impact that food has on their growth, and that some things can harm, at least information is available up front."He also urged councils to impose "fast-food-free zones" around schools and hospitals – areas within which takeaways cannot open.A Department of Health spokesperson said: "We need to create a new vision for public health where all of society works together to get healthy and live longer. This includes creating a new 'responsibility deal' with business, built on social responsibility, not state regulation. Later this year, we will publish a white paper setting out exactly how we will achieve this."The food industry will be alarmed that such senior doctors back such radical moves, especially the call to use some of the tough tactics that have been deployed against smoking over the last decade.Section III TranslationDirections: In this section there is a passage in English. Translate it into Chinese and write your version on ANSWER SHEET 2. (15 points)We would have thought that globally, the IT industry produces about the same volume of greenhouse gases as the world’s airlines do- roughly 2 percent of all CO2 emissions?Many everyday tasks take a surprising toll on the environment Google search an leak between 0.2 and 0.7 grams of C2O,depending on how many attempts are needed to get the "right‖ answer. To deliver results to its needs quickly, then, Google has to maintain vast data centers around the world, packed with powerful computers. While producing large quantities of C2O,these computers emit a great deal of heat, so the centre need to be well air-confirmed gases even more energy.However, Google and other big tech providers monitor their efficiency quickly and make improvements. Monitoring is the first step on the need to production, but there is much more to be done, and not just by big companies.Section IV WritingPart A47.Directions:Suppose your cousin Li Ming has just been admitted to a university. Write him/her a letter to:(1)congratulate him/her, and(2)give him/her suggestions on how to get prepared for university life.You should write about 100 words on ANSWER SHEET 2.Do not sign your own name at the end of the letter. Use "Zhang Wei" instead.Do not write the address. (10 points)Part B48.Directions:Write a short essay based on the following chart. In your writing, you should:1)interpret the chart and2)give your comments.You should write at least 150 wordsWrite your essay on ANSWER SHEET 2.(15points)2008、2009年国内轿车市场部分品牌份额示意图参考答案选择题:1-5ACBDD 6-10BACCA 11-15DBACA 16-20CDACD21-25BBDAA 26-30DBCBB 31-35BDCDB 36-40DCBAC 41-45EDCFG46翻译有谁会想到,在全球范围内,IT行业产生的温室气体跟全球航空公司产生的一样多?占二氧化碳总排量的2%.很多日常工作对环境造成了让人震惊的破坏作用。
西北工业大学801计算机专业基础2011年(回忆版)考研专业课真题试卷
西北工业大学801计算机专业基础2011年考研真题(回忆版)计算机网络部分试题
一、名词解释
1.TCP/IP
2.POP3
3.CMOS
4.PCI
5.PAD
6.HDLC
7.QoS
8.SMTP
10.IRC
二、简答题
1.局域网基本拓扑构型主要分为哪三类?它们之间有什么区别与联系?
2.具体的网络系统集成可以划分为哪些阶段?
3.以太网交换机主要分为哪些类型?在以太网交换机选型上应考虑哪些问题?
4.什么是电子商务的概念?电子商务有哪些类型?电子商务有哪些主要特点?
5.请说明Telnet服务的基本工作原理。
三、应用题
某局域网采用CSMA/CD协议实现介质访问控制,数据传输率为100M/S,主机甲和主机已的距离为2KM,信号传播速速时200000M/S 请回答下列问题,并给出计算过程。
(1)、若主机甲和主机已发送数据时发生冲突,则从开始发送数据时刻起,到两台主机均检测到冲突时刻为止,最短经过多长时间?最长经过多长时间?(假设主机甲和主机已发送数据时,其它主机不发送数据)。
西北工业大学821自动控制原理2011模拟题与答案
六、非线性控制系统如图 5 所示,图中非线性环节的描述函数为(25 分)
N(X ) = 8
πX
1 − ⎜⎛ ⎝
1 X
2
⎟⎞ ⎠
−
8 j πX 2
X >1
Figure5:非线性控制系统
(ⅰ)设系统处于稳定自振状态时,线性环节
G(s
)
=
2k
s(s +1)
的相角迟后量为135° ,求此
时的 K 值,并确定输出端自振频率、幅值。 (ⅱ)定性分析当 K 值增加时,系统输出端自振频率、幅值的变化趋势
频率特性为: We ( jω)
=
8( jω + 4) 6ω j +16 −ω 2
C(s)
8 s+2
1 s+4
当系统作用为 n(t ) = 4 sin 3t 时, ω = 3,所以
报考专业:
西北工业大学
2011 年硕士研究生入学考试模拟试题(二)
科目代码:
8 21
科目名称: 自动控制原理
所有答案必须做在答案题纸上,做在试题纸上无效!
一、已知一控制系统的结构图如下(25 分)
1) 确定该系统在输入信号 r (t ) = 1(t )下的时域性能指标:超调量 σ % ,调节时间 ts 和峰值
二、闭卷考试,考生进入考场,不得携带任何书刊、笔记、报纸和通讯工具(如手机、 寻呼机等),或有存储、编程、查询功能的电子用品(如已携带,必须存放在监考老师指定 的地方)。考生只准带必需的文具,如钢笔、圆珠笔、铅笔、橡皮、绘图仪器或根据考试所 需携带的用具。能否使用计算器,及开卷考试时允许携带的书籍及用具等由任课教师决定。
时间 t p ;
2) 当 r (t ) = 2⋅ 1(t ),n(t ) = 4 sin 3t 时,求系统的稳态误差。
西工大航天研究生科目2011
附件二:2011年攻读硕士学位研究生招生专业目录学科、专业代码及名称研究方向代码及名称指导教师招生人数考试科目备注002航天学院90 081105 导航、制导与控制3001 航天器及导弹制导与控制系统周军教授闫杰教授杨军教授张科教授黄攀峰教授于云峰教授郭建国副教授符文星副教授刘莹莹副教授王红梅副教授余瑞星副教授葛致磊副教授于晓洲副教授卢晓东副教授呼卫军副教授101政治201英语301数学(一)821自动控制原理836航天器与导弹任选控制原理联系人:李栓学029-*******4复试科目:936现代控制理论基础同等学力加试科目:导弹控制原理航天器控制原理接受推免研究生4名02飞行器控制与仿真技术周军教授闫杰教授翁志黔教授梁志毅教授张科教授王民钢教授黄攀峰教授于云峰教授符文星副教授刘莹莹副教授谭雁英高工王红梅副教授余瑞星副教授葛致磊副教授于晓洲副教授王鑫副教授呼卫军副教授陈凯副教授卢晓东副教授03先进控制理论及技术周军教授闫杰教授杨军教授黄攀峰教授于云峰教授郭建国副教授符文星副教授刘莹莹副教授谭雁英高工葛致磊副教授04通信、测控、信息安全与对抗技术周军教授闫杰教授张科教授于晓洲副教授王鑫副教授陈凯副教授082303 交通运输规划与管理 401新航行系统袁建平教授方群教授罗建军教授岳晓奎教授101政治201英语任214德语(一外)选301数学(一)821自动控制原理任839飞行器飞行力学选复试科目:937卫星定位导航基础同等学力加试科目:航天器飞行力学组合导航技术214德语(一外)只限报袁建平、岳晓奎接受推免研究生1名02空间交通管理与控制袁建平教授方群教授罗建军教授岳晓奎教授082501 飞行器设计2901飞行器总体设计王兴治院士谷良贤教授文立华教授谢宗蕻教授杨茂副教授龚春林副教授徐超副教授101政治201英语任选一214德语(一外)301数学(一)837 气体动力学842 飞行力学与任选一结构力学复试科目:938飞行器总体设计同等学力加试科目:飞行器总体设计飞行器结构设计航天器飞行力学组合导航技术任选2门214德语只限报袁建平、岳02飞行器结构设计文立华教授谢宗蕻教授吴斌副教授徐超副教授03飞行器飞行动力学与控制袁建平教授唐硕教授徐敏教授方群教授祝小平教授罗建军教授李新国教授王志刚教授岳晓奎教授朱战霞教授刘芸副教授马卫华副教授晓奎接受推免研究生2名04空天飞行器系统与技术谷良贤教授袁建平教授唐硕教授徐敏教授方群教授罗建军教授李新国教授岳晓奎教授朱战霞教授马卫华副教授龚春林副教授05飞行器系统工程与仿真袁建平教授唐硕教授祝小平教授罗建军教授李新国教授王志刚教授刘芸副教授082502 航空宇航推进理论与工程1901 发动机总体设计毛根旺教授李进贤教授鲍福廷教授胡春波教授李江教授刘佩进教授杨涓教授唐金兰副教授孙得川副教授胡松启副教授李强副教授张研副教授101政治201英语任选一213日语(一外)301数学(一)837 气体动力学842 飞行力学与任选一结构力学复试科目:940火箭发动机设计同等学力加试科目:气体动力学火箭发动机原理工程热力学任选2门,但不能和初试科目相同213日语(一外)限报毛根旺老师接受推免研究生1名02 发动机燃烧与流动何国强教授李进贤教授胡春波教授李江教授刘佩进教授唐金兰副教授冯喜平副教授孙得川副教授王英红副教授胡松启副教授李强副教授03 传热、传质与热结构毛根旺教授何国强教授冯喜平副教授孙得川副教授王英红副教授张研副教授04 测试、热工程信息处理、状态检测及故障诊断何国强教授刘佩进教授胡松启副教授孙得川副教授05 特种发动机技术毛根旺教授何国强教授杨涓教授冯喜平副教授082602 兵器发射理论与技术 401运载火箭发射故障检测、诊断与仿真闫杰教授王民钢教授黄攀峰教授于云峰教授101政治201英语301数学(一)836航天器与导弹任控制原理843火箭发动机原理选复试科目:936现代控制理论基础同等学力加试科目:导弹控制原理航天器控制原理接受推免研究生1名02发射动力学智能控制与发控系统工程周军教授张科教授082603 火炮、自动武器与弹药工程401特种高能燃料何国强教授王英红副教授101政治201英语任选一213日语301数学(一)836航天器与导弹控制原理任选843火箭发动机原理复试科目:940火箭发动机设计同等学力加试科目:气体动力学火箭发动机原理工程热力学任选2门,但02弹箭增程技术毛根旺教授李进贤教授鲍福廷教授胡春波教授03弹箭总体结构设计何国强教授毛根旺教授李进贤教授鲍福廷教授王英红副教授不能和初试科目相同213日语(一外)限报毛根旺接受推免研究生1名430111 控制工程15周军教授闫杰教授翁志黔教授梁志毅教授杨军教授张科教授王民钢教授黄攀峰教授于云峰教授郭建国副教授符文星副教授刘莹莹副教授谭雁英高工王红梅副教授余瑞星副教授葛致磊副教授于晓洲副教授卢晓东副教授呼卫军副教授王鑫副教授陈凯副教授101政治204英语(二)302数学(二)821自动控制原理836航天器与导弹任选控制原理复试科目:936现代控制理论基础同等学力加试科目:导弹控制原理航天器控制原理430134 航天工程25王兴治院士谷良贤教授文立华教授谢宗蕻教授袁建平教授唐硕教授徐敏教授方群教授祝小平教授罗建军教授李新国教授王志刚教授岳晓奎教授朱战霞教授毛根旺教授101政治204英语(二)302数学(二)837 气体动力学842 飞行力学与任选一结构力学复试科目:938飞行器总体设计940 火箭发动机任选1门同等学力加试科目:飞行器总体设计飞行器结构设计航天器飞行力学组合导航技李进贤教授鲍福廷教授胡春波教授李江教授刘佩进教授杨涓教授何国强教授杨涓教授杨茂副教授吴斌副教授龚春林副教授徐超副教授刘芸副教授马卫华副教授唐金兰副教授孙得川副教授胡松启副教授李强副教授张研副教授冯喜平副教授王英红副教授术气体动力学火箭发动机原理任选2门航天学院2010-5-28专业课及复试科目大纲题号:836《航天器与导弹控制原理》考试大纲一、考试内容根据我校教学及该试题涵盖专业的特点,对考试范围作以下要求:1.航天器控制的基本概念:航天器的分类和系统组成、航天器控制系统的基本任务和基本概念;2.航天器的轨道与姿态动力学和运动学:航天器轨道的基本定理、二体问题与方程、轨道的描述、轨道摄动;姿态动力学方程、航天器的一般运动方程、姿态干扰力矩;3.航天器的姿态控制系统总体:系统总体结构、敏感器工作原理、执行机构工作原理; 4.航天器的被动姿态控制系统:自旋卫星的稳定原理和章动性、章动阻尼、重力梯度稳定原理;5.航天器主动控制系统:推力器姿态稳定原理,飞轮姿态稳定原理、零动量轮三轴姿态稳定系统、控制力矩陀螺姿态稳定系统;自旋稳定卫星的喷气姿态机动和磁线圈姿态机动控制、航天器的姿态捕获。
西工大往年考试题及答案
西工大往年考试题及答案一、单项选择题(每题2分,共20分)1. 以下哪个选项是西工大的全称?A. 西安工业大学B. 西北工业大学C. 西南工业大学D. 西安工程大学答案:B2. 西工大位于哪个城市?A. 北京B. 上海C. 西安D. 广州答案:C3. 西工大的校训是什么?A. 厚德博学,求实创新B. 求真务实,自强不息C. 厚德载物,自强不息D. 厚德博学,自强不息答案:A4. 西工大的校庆日是哪一天?A. 5月1日B. 10月1日C. 9月1日D. 7月1日5. 西工大的校徽颜色是什么?A. 蓝色B. 红色C. 绿色D. 黄色答案:B6. 西工大的图书馆藏书量超过多少万册?A. 100万B. 200万C. 300万D. 400万答案:C7. 西工大的校歌名称是什么?A. 西工大之歌B. 飞翔的翅膀C. 梦想的翅膀D. 翱翔的翅膀答案:A8. 西工大的校史馆位于校园的哪个位置?A. 东门附近B. 南门附近C. 西门附近D. 北门附近答案:B9. 西工大的校花是什么?B. 玫瑰C. 菊花D. 荷花答案:A10. 西工大的校庆活动通常在每年的哪个月份举行?A. 5月B. 9月C. 10月D. 12月答案:C二、多项选择题(每题3分,共15分)1. 西工大的校园文化包括以下哪些方面?A. 学术讲座B. 体育竞技C. 艺术表演D. 社会实践答案:ABCD2. 西工大的科研方向主要包括哪些领域?A. 航空航天B. 材料科学C. 信息技术D. 生物医学答案:ABCD3. 西工大的学术资源包括以下哪些?A. 图书馆B. 实验室C. 研究中心D. 博物馆答案:ABCD三、填空题(每题2分,共10分)1. 西工大的校训是“_______,_______”。
答案:厚德博学,求实创新2. 西工大的校庆日是每年的_______月_______日。
答案:10月1日3. 西工大的校徽颜色是_______色。
答案:红色4. 西工大的校歌名称是_______。
西北工业大学政治学原理2011年考研专业课初试真题
西北工业大学
2011年硕士研究生入学考试试题试题名称:政治学原理
说明:所有答题一律写在答题纸上
一、名词解释(每题6分,共30分)
1、历史制度主义
2、社会契约论
3、政治权力
4、行政救济监督
5、精英民主论
二、简答题(每题10分,共60分)
1、什么是分权学说。
2、简述行为主义政治学的基本特征。
3、国家职能中政治职能和社会职能的关系。
4、政治参与的基本特征。
5、政党与利益集团的区别。
6、简述中国共产党领导的多党合作制的优点。
三、论述题(每题20分,共60分)
1、论述在社会转型时期,国家职能与社会公正的关系。
2、论述政治发展与社会发展的关系。
西北工业大学 研究生考试真题+习题 自动控制原理
2002年硕士研究生入学考试试题试题名称:自动控制原理 试题编号:541说明:所有试题一律写在答题纸上 共 3 页 第 3 页221-=K , 1)(=s H2002年硕士研究生入学考试试题试题名称:自动控制原理试题编号:541说明:所有试题一律写在答题纸上共 3 页第 3 页2002年硕士研究生入学考试试题试题名称:自动控制原理试题编号:541说明:所有试题一律写在答题纸上共 3 页第 3 页试题名称:自动控制原理 试题编号: 427试题名称:自动控制原理 试题编号: 427试题名称:自动控制原理 试题编号: 427西北工业大学2004年硕士研究生入学考试试题试题名称:自动控制原理(A 卷) 试题编号: 427 说 明:所有答题一律写在答题纸上 第 1 页 共 3 页1.(25分)已知系统结构图如图1所示(1) 确定使系统稳定的参数t K K ~0的取值范围,并在t K K ~0平面上表示出来;(2) 要求在2)(2t t r =作用下系统的稳态误差0=ss e ,试确定)(s G c 的表达式。
2.(25分)系统结构图如图2所示(1) 绘制当∞→变化时的系统根轨迹(求出渐近线,分离点,与虚轴交点),确定使系统稳定的开环增益=00K K 的取值范围;(2) 若已知闭环系统的一个极点为11-=λ,试确定系统的闭环传递函数。
试题名称:自动控制原理(A 卷) 试题编号: 427 说 明:所有答题一律写在答题纸上 第 2 页 共 3 页3.(25分)某单位反馈的最小相角系统,其开环对数幅频特性如图3所示。
(1) 写出系统开环传递函数)(s G 表达式; (2) 求系统的截止频率c ω和相角裕度γ。
[ 注:振荡环节的谐振频率221ξωω-=n r ,谐振峰值2121ξξ-=r M ]4.(25分)系统结构图如图4所示,被控对象的传递函数为)101.0)(11.0()(0++=s s s Ks G(1) 当1)(=s G c 时,若要求系统的静态误差系数100=v ,试判断系统此时是否稳定;K (2) 令100=K ,为使系统获得大于︒30的相角裕度,采用校正装置 1005.0105.0)(++=s s s G c试验证校正后系统是否满足要求。
西北工业大学研究生入学考试机械原理题库1
第二章 平面机构的结构分析题2-1 图a 所示为一简易冲床的初拟设计方案。
设计者的思路是:动力由齿轮1输入,使轴A 连续回转;而固装在轴A 上的凸轮2与杠杆3组成的凸轮机构使冲头4上下运动,以达到冲压的目的。
试绘出其机构运动简图(各尺寸由图上量取),分析是否能实现设计意图,并提出修改方案。
解:1)取比例尺,绘制机构运动简图。
(图2-1a)2)要分析是否能实现设计意图,首先要计算机构的自由度。
尽管此机构有4个活动件,但齿轮1和凸轮2是固装在轴A 上,只能作为一个活动件,故3=n 3=l p 1=h p01423323=-⨯-⨯=--=h l p p n F原动件数不等于自由度数,此简易冲床不能运动,即不能实现设计意图。
分析:因构件3、4与机架5和运动副B 、C 、D 组成不能运动的刚性桁架。
故需增加构件的自由度。
3)提出修改方案:可以在机构的适当位置增加一个活动构件和一个低副,或用一个高副来代替一个低副。
(1) 在构件3、4之间加一连杆及一个转动副(图2-1b)。
(2) 在构件3、4之间加一滑块及一个移动副(图2-1c)。
(3) 在构件3、4之间加一滚子(局部自由度)及一个平面高副(图2-1d)。
11(c)题2-1(d)54364(a)5325215436426(b)321讨论:增加机构自由度的方法一般是在适当位置上添加一个构件(相当于增加3个自由度)和1个低副(相当于引入2个约束),如图2-1(b )(c )所示,这样就相当于给机构增加了一个自由度。
用一个高副代替一个低副也可以增加机构自由度,如图2-1(d )所示。
题2-2 图a 所示为一小型压力机。
图上,齿轮1与偏心轮1’为同一构件,绕固定轴心O 连续转动。
在齿轮5上开有凸轮轮凹槽,摆杆4上的滚子6嵌在凹槽中,从而使摆杆4绕C 轴上下摆动。
同时,又通过偏心轮1’、连杆2、滑杆3使C 轴上下移动。
最后通过在摆杆4的叉槽中的滑块7和铰链G 使冲头8实现冲压运动。
西北工业大学机械设计考研真题
2010年机械设计真题回忆填空:和往年真题有一些重复,但并不是很多。
出现了一些类似“润滑油的粘度分为-,-,和条件粘度”的这种我超级陌生的题目问答:一个是齿轮齿数增加会有什么影响,另一个讨论链传动的节距和齿数的变化会影响什么?还有一个画螺栓结构图分析:1.讨论可不可以把带轮轮槽做的粗糙一点来提高当量摩擦系数,从而提高带的有效拉力2.想不起来了计算:1.关于螺栓校核(考过)2.极限疲劳应力曲线(考过)3.带传动和轴承的综合题,注意求轴承的寿命是L10,而不是L,我就在这里崩溃了,从没关注过这个公式,完全忘记。
4.键的校核。
这道题很让人崩溃,给的是一对齿轮,校核其中一个齿轮的键,给了N多条件,超级让人崩溃,这道题我完全摸不着头脑 5.轴的设计·。
注意不是改错哦,完全要自己画一根轴,上面布置齿轮啊,轴承啊,联轴器啊什么的。
感觉今年和往年有不少差异,也许是学校知道往年真题已经在网络上大面积流传遂更新了题库?填空:和往年真题有一些重复,更注重基础知识的理解,和常识的考察。
问答:1.在中心距、分度圆一定时,一个是齿轮齿数增加,对齿轮有何影响?2.一个讨论链传动的节距和齿数的变化会影响什么?3.一个铰制孔用螺栓结构图。
分析:1.讨论可不可以把带轮轮槽做的粗糙一点来提高当量摩擦系数,从而提高带的有效拉力?2.合理布置轴上零件以减少轴的载荷?给出两种动力输入方案,让你判断哪一个方案更合理,并给出因。
计算:1.关于受轴向力的螺栓校核(考过)。
2.极限疲劳应力曲线(考过)。
3.带传动和轴承的综合题,注意求轴承的寿命是L10。
4.键的校核。
有一定的综合性,题目给出了很多的已知条件,要学会自己处理给定的已知条件。
5.轴的设计·。
注意不是改错哦,完全要自己画一根轴,要使轴实现良好的轴向定位与轴向定位。
填空:比較瑣碎,但真題重現率還算高,如版主所說的比率問答和分析差不多感覺《《當時卷子上寫好多工業設計考生不做,其他考生必做什麽的,搞得我漏做第三題,快交卷才發現》》。
2011年在职研究生入学考试各科练习题
2011年在职研究生入学考试各科练习题各科练习题说明:此练习题仅供辅导教师和考生在复习过程中进行练习及掌握考试题型之用,不是复习重点。
请考生按照大纲进行全面复习。
政治理论一、概念解释题哲学的基本问题、商品、抽象劳动、价值规律、剩余价值、可变资本、实践、人民内部矛盾、党的三大优良作风、和平共处五项原则、感性认识、理性认识、主要矛盾、矛盾的普遍性、民主集中制、社会主义核心价值体系二、辨析题1.实践性是马克思主义哲学的唯一特点。
2.对新事物要肯定一切,对旧事物要否定一切。
3.具体劳动创造使用价值,抽象劳动创造价值,所以它们是两类独立存在的劳动。
4.市场经济以市场作为资源配置的基础性手段,但它并不排斥国家对经济的宏观调控。
5.发展才是硬道理,这里所说的―发展‖是指经济发展。
6.马克思主义认识论是以实践为基础的能动的革命的反映论。
7.内因和外因作为同时存在的内部和外部的联系,对事物发展起着相同的作用。
8.社会主义公有制的实现形式可以而且应当多样化。
9.革命是解放生产力,改革是发展生产力。
10.中国共产党领导的多党合作与政治协商制度是中国的一项基本政治制度。
11、改革、发展、稳定三者之间的关系是辩证统一的。
12、实践作为检验真理的标准,既是绝对的又是相对的,是确定性和不确定性的统一。
13、社会主义民主政治只是为社会主义经济基础服务的有力手段。
14.未来社会是一个自由人联合体。
15.代表中国最广大人民的根本利益,必须妥善处理人民内部的各种利益关系。
16.我们党的执政地位不是一劳永逸、一成不变的。
三、简答题1.简述马克思主义产生的社会历史条件。
2.马克思主义的三个理论来源是什么?3.马克思根据社会关系的历史发展与人的个性发展的内在联系把人的发展划分为哪三个大的历史阶段?4.简述马克思对生产与消费之间关系的论述。
5.列宁是如何论述唯心主义的认识论根源的?6.列宁是如何论证对立统一规律是辩证法的核心和实质的?7.列宁关于辩证法和形而上学两种发展观的论述。
西北工业大学
西北工业大学2011年硕士研究生入学考试试题试题名称:材料科学基础(A 卷) 试题编号:832 说 明:所有答题一律写在答题纸上 第 1 页 共 2 页一、 简答题(每题10分,共50分)1. 请从原子排列、弹性应力场、滑移性质、柏氏矢量等方面对比刃位错、螺位错的主要特征。
2. 何谓金属材料的加工硬化?如何解决加工硬化对后续冷加工带来的困难?3. 什么是离异共晶?如何形成的?4. 形成无限固溶体的条件是什么?简述原因。
5. 两个尺寸相同、形状相同的铜镍合金铸件,一个含90%Ni ,另一个含50%Ni ,铸造后自然冷却,问哪个铸件的偏析严重?为什么?二、 作图计算题(每题15分,共60分)1、 写出{112}晶面族的等价晶面。
2、 请判定下列反应能否进行:]001[]111[2]111[2a a a →+3、 已知某晶体在500℃时,每1010个原子中可以形成有1个空位,请问该晶体的空位形成能是多少?(已知该晶体的常数a =0.0539,波耳滋曼常数K =1.381×10-23 J / K )4、单晶铜拉伸,已知拉力轴的方向为[001],σ=106 Pa ,求(111)面上柏氏矢量的螺位错线上所受的力()三、 综合分析题(共40分)1. 经冷加工的金属微观组织变化如图a 所示,随温度升高,并在某一温度下保温足够长的时间,会发生图b-d 的变化,请分析四个阶段微观组织、体系能量和宏观性能变化的机理和原因。
2.根据Ag-Cd二元相图:1)当温度为736℃、590℃、440℃和230℃时分别会发生什么样的三相平衡反应?写出反应式。
2)分析Ag-56%Cd合金的平衡凝固过程,绘出冷却曲线,标明各阶段的相变反应。
3)分析Ag-95%Cd合金的平衡凝固与较快速冷却时,室温组织会有什么差别,并讨论其原因。
2011年西工大附中入学语文真卷
2011年西工大附中入学语文真卷(一)一、积累与运用(共70分)1.成语填空。
(4分)美不()收盛气()人精兵()政()心独运2.注音或写汉字(3分)jiàn 赏(2)对chèn (3)感kǎi 玫瑰()精髓()脂肪()挑衅()炫耀()3.诗句填空。
(4分)(1),桂树何团团。
(2)九曲黄河万里沙,。
(3)寒雨连江夜入吴,。
(4)我劝天公重抖擞,。
(5)会当凌绝顶,。
(6)人生自古谁无死,。
(7)天街小雨润如酥,。
(8)春蝉到死丝方尽,。
4.仿写句子。
(2分)朋友是快乐日子里的一把吉他,尽情地为你弹奏生活的愉悦。
朋友是。
5.《红楼梦》中有一个女子,她模样标致,语言犀利,心机极深细,但“机关算尽太聪明,反误了卿卿性命”,这个人是;还有一个女子,她寄人篱下,渴望真挚的爱情,但在森严冷漠的封建大家庭中,只能凄婉地唱出“一年三百五十六日,风刀霜剑严相逼”,这个人就是。
(2分)6. 同学们,古诗词是我国灿烂的文化瑰宝,在六年的学习中,你一定学会了很多首古诗词,试试看,你跟根据要求把古诗词写正确吗?(5分)(1),人情练达即文章。
(2)春天的一个夜晚,一位久别家乡的人,望着皎洁的月光不禁想起了家乡,于是吟起诗来:,。
(3)有的同学不认真学习,不知道珍惜时间,老师就语重心长地说“ , 。
”7. 名著阅读:请你写出一个出自小说《三国演义》的人物和与之相关的故事。
(2分)二、语言运用。
(8分)1.一个顾客在酒吧里喝啤酒,他喝完第二杯后,转身问酒吧的老板:‚你们一周能卖掉多少桶啤酒?‛老板得意洋洋地回答说:‚35桶。
‛顾客说:‚我倒想出一个能使你每周卖掉70桶的办法。
‛老板很惊讶,急忙问:‚什么办法?‛顾客说:‚这很简单,你只要将每个杯子里的啤酒装满就行。
‛(1)老板急于讨教卖酒的办法,暴露了他什么心态?(2分)答:(2)顾客的话中有何言外之意?(2分)答:2.班上准备举行一次古代风流人物诗歌朗诵会,要求每位同学选择自己喜欢的诗文,认真准备,力求声情并茂地进行朗诵,从中感受风流人物的情怀。
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2011年西工大电气工程研究生入学考试题
电机部分
一、填空:
1、直流电机的极对数为Z,绕组为单叠绕组,则绕组支路对数等于
2、一台他励直流发电机的电枢绕组中的电流方向是交变的还是不变的
3、变压器的空载试验,可以求得等效电路的什么电路参数?短路试验,可以求得等效电路的什么电路参数
4、变压器运行时,满足什么条件下,变压器效率最高。
5、图一所示为三相交流绕组中的A相绕组的展开图,该三相交流绕组的并联支路数为
6、三相感应电动机工作在发电机状态,其转差率零。
(大于,等于,小于)
7、一台笼型异步电动机,原来转子是插铜条的,为降低成本将铜改为铸铝,改后该电机最大转矩如何变化。
(变大,变小,不变)
8、在电励磁同步电发机输出有功功率恒定时,改变能改变发电机输出无功功率的变化。
9、交流绕组采用分布和削弱谐波电动势。
二、简答:
1、并励直流发电机自励的条件是什么?
2、某直流发电机,一对极,逆时针运转,保持电枢电流不变,若将其电刷逆着转向偏离了几何中性线15°,试分析对电机磁场的影响。
3、简述三相同步发电机的原理。
4、为什么三相异步电动机转子磁动势相对于定子磁动势静止?
5、画出阴极同步发电机的功角特性,(0°——180°范围内)标出稳定运行区域。
三、计算题
1、一台他励直流电动机的额定参数为:PN=32KW,UN=400V,IN=95A,Nn=1500r/min,电枢回路总电阻为Ra=0.5Ω,忽略空载转矩及其电枢反应的影响,计算:(1)电机的电磁转矩
(2)电机的效率
(3)若电机拖动0.75倍的额定负载转矩运行,电动机的转速是多少?
2、
(1)极数2p
(2)同步转速n1
(3)额定负载时的转差率
(4)额定负载时转子电流
(5)给出T型等效电路
(6)用T型等效电路计算额定负载时的定子相电流Id,输入功率P,功率因数cosψ,和折算到定子边的转子相电流。
3、已知一台三相四极凸极同步电机的X1σ标幺值等于1,X2σ标幺值等于0.6
(参数见图),接在频率为50HZ的电网上,U标幺值等于1,运行工况为电流I 标幺值等于1,cosψ=0.8(滞后),忽略定子电阻,不计饱和,计算:
(1) E0与I的夹角
(2) E0与U的夹角
(3)反电势标幺值
(4)电磁功率标幺值
(5)输出功率标幺值
电力电子部分:
四、填空:
1、相控调压和周波数调压的原理区别是
2、电力电子器件的损耗包括在高频工作状态下,为减少损耗,可采用技术。
3、在GTR.GTO及POWER MOSFET开关器件中,更适合工作在并联状态,因为
4、电力二极管的反向恢复过程是
5、由二极管组成的三相桥式整流电路,由380V供电,阻感性负载,且L极大,若希望变换装置输出电压为600V,则变压器二次侧线电压有效值为,若整流装置最大输出电流为80A,则变压器容量为。
五、简答题:
1、画出Cuk斩波电路原理图,设开关导通占空比为D,推导出输入电压,输出电压与D的关系。
2、SVPWM控制的单相逆变电路中,若载波为三角波,频率为20kHZ,幅值为1,
调制波频率为400HZ,则开关器件的开关频率是多少?逆变器输出电压基波频率是多少?主要谐波有哪些?可通过调节载波或调制波的哪些参数控制逆变器输出电压的幅值?
3、具有旁路电源系统的UPS原理框图如图2所示,试说明其工作过程。
当负载容量为6kVA,功率因数为0.75,逆变器效率为90%,直流母线电压196V,蓄电池容量10Ah,当市电断电后,备用发电机需要多长时间内投入工作?才能保证UPS 不间断供电?
4、试画出硬开关和软开关的开关过程中电压、电流和功率的波形,并加以比较,简要说明软开关的特点。
六、综合题
1、画出由晶闸管构成的单相全波可控整流电路原理图,若负载为阻感性,且wL>>R,且输出反并联续流二极管,设控制角为α,变压器漏感为Ld,试画出输出电压和晶闸管承受电压的波形,并推导输出电压Ud=f(U2, α,Ld)的关系,U2为整流变压器二次侧电压。
2、三相桥式整流电路,如图3所示,反电动势阻感性负载,已知交流输入整流变压器二次侧相电压为u2=根号2*115sin(800πt),L极大,R=1.2Ω,Ld=1mH,EM=-300V,β=60°时,求输出电压电流的平均值和送回电网的有功功率是多少?
3、已知三相半波可控整流电路如图4所示,市网供电,整流变压器变比为1:1,
反电动势阻感负载,R=10Ω,L=无穷的,E=40V,整流变压器绕组的漏感Lh=1.0mH,U2=100V,当α=25°时,求:
(1) Ud,Id和变压器二次侧的功率因数。
(2)作出Ud,晶闸管电流iT1和i1对应u2的曲线。