2011B卷
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第 页 共4 页北方民族大学试卷课程代码: 01100522 课程: 通信原理 (B 卷答案)(闭卷考试、要求学生携带计算器)一、单项选择题(在每小题的四个备选答案中,选出一个正确答案,并将正确答案的序号填在题中的括号内。
每小题1分,共15分)1、数据通信中,在计算调制速率时,信号码元时长是指 ( C . )A .信号码元中的最短时长B 。
信号码元中的最长时长C . 信号码元中的平均时长D 。
信号码元中的任意一个码元的时长 2、 串行数据传输的特点是 ( A. )A. 在一条线上,一次产生一位。
B. 在不同线上,同时产生几位C. 由于存在移位寄存器,位不可能产生。
D. 在系统存贮器中,但按矩阵形式产生3、离散信源输出五个不同符号,若各符号概率分别为1/2,1/4,1/8,1/16,1/16,则该信源的熵为多少 ( B. )。
A. 1.5bit/符号 B. 1.875 bit/符号 C. 2 bit/符号 D. 1 bit/符号 4、.一个二进制数字信号码元时间长度为0.1μs ,在传输过程中平均2.5秒产生一个错码,则其平 均误码率近似为 ( D. ) A. 5×10-6 B.2×10-8 C.2×10-7 D.4×10-85、n 维高斯过程,各统计样本之间的不相关特性与统计独立有如下关系 ( B. ) A.没有直接的关系 B.等价 C.不等价 D.不相关不一定统计独立6、均匀量化器在过载区的量化误差 ( c )A.<2∆B.<△C. > 2∆D.>有时<2∆,有时>2∆7、相位键控(PSK)属于那种________________调制。
( A )A. 线性B. 非线性C. 正交平衡D. 幅度调制8、DPCM 的提出主要基于考虑为 ( B. )A.电路实现简易B.减小速码率,压缩频带C.改善信噪比D.扩大信号的动态范围9、下列几种调制方式中,频带利用率最差的调制方式是 (B ) A.2Ask B.2Fsk C.2DPsk D.2Psk10、在中波(AM)调幅广播中,如果调制信号带宽为20KHz ,发射机要求的总带宽为 ( A. )A. 40KHzB. 20KHzC. 80KHzD. 10KHz11.对数字通信中再生中继器的有关描述,不正确的是哪个? ( D. )A.放大和均衡信号B.消除误码C.消除噪声积累D.有误码积累 12.A 律13折线通常采用的量化级数为 ( B. )A.16B.256C.128D.204813、关于多进制数字调制,下列说法不正确 ( D. )A. 相同码元传输速率下,多进制系统信息速率比二进制系统高。
苏州大学医学部2011年研究生课程进修班英语入学考试(B卷)姓名考生单位________________ 得分Part 1 V ocabulary 20%1.Tom was extremely angry, but cool-hearted enough to ___________ storming into the boss’soffice.A. preventB. prohibitC. refrainD. avoid2. An individual bird can __________ the call of its own species.A. identifyB. nameC. easeD. entitle3. I felt I couldn’t cope with the situation and was in desperate need of some ___________.A. remarkB. reassuranceC. suggestionD. claim4. She ___________ great satisfaction from her coin collection.A. extractsB. derivesC. devotesD. awaits5. They can go whenever they like, ___________ I’m concerned.A. as well asB. as much asC. as long asD. as far as6. I’d like to __________ five hundred dollars to my current account.A. shiftB. moveC. changeD. transfer7. The two universities will unite to ____________ an art show next month.A. openB. stageC. doD. buy8. The only _________ to the farmhouse is across the fields.A. accessB. methodC. stepD. means9. She likes being with young people and considers teaching a ___________ career.A. worthB. worthwhileC. worseD. worthless10. Y our story __________ me of my childhood spent in a little town.A. recordsB. remembersC. remainsD. reminds11. The corridor was dark and I ___________ my head against the wall.A. broughtB. damagedC. bumpedD. struck12. Do you think there is any __________ of him passing the entrance examination?A. chanceB. considerationC. occasionD. success13. The manager asked me if I had had any ___________ experience of the job.A. earlyB. originalC. formerD. previous14. If the sun’s ray are _________ on a point on the paper, the paper will catch fire.A. gatheredB. collectedC. focusedD. assembled15. It seemed as if all of a ___________ the animal had smelt danger in the air.A. momentB. suddenC. flashD. attack16. The news __________ that the firm was closing down on account of bad management.A. got aboutB. came downC. took aroundD. went over17.___________ you are here, I can leave.A. So thatB. Such thatC. Now thatD. In order that18. Don’t _______ that you can succeed without hard work.A. intendB. supposeC. endeavorD. seek19. Mr. Black built fences to __________ the boundaries of his land.A. markB. signC. confineD. post20. They are nice boys and I am sure you will get on _________ them very well.A. byB. withC. towardD. beside21. As soon as he arrived, he ___________ putting the house in order.A. set outB. set aboutC. set inD. set up22. As the shortage of certain metals approaches, others must be bound to take their _______.A. shareB. placeC. roleD. shape23. A flying stone __________ him on the head and knocked him out.A. beatB. hitC. strikeD. flog24. The farmers __________ a mysterious object flying over when they made their way home.A. kept up withB. made use ofC. caught sight ofD. held themselves in25. In those miserable days, his kind words gave me great _________.A. considerationB. concernC. conductD. comfort26. That small country has __________ independence.A. orderedB. performedC. exclaimedD. declared27. It is very kind of you to ________ me _________ at the airport.A. see offB. meet withC. see throughD. see to28. It isn’t _________ that I should accept such an offer as that.A. likeB. likelihoodC. likelyD. alike29. She could _________ no sympathy from Jack.A. makeB. thinkC. expectD. estimate30. Spare the rod, _________ the child.A. harmB. frightenC. spoilD. hurt31. Helen and Ruth are always at _________ about some little thing.A. oddB. lossC. oddsD. order32. Johnnie’s hard work and popularity led to his rise in salary and ___________ in position.A. privilegeB. complimentsC. promotionD. advantage33. With easy articles and interesting information, this newspaper is designed for readers.A. normalB. averageC. efficientD. literary34. A large proportion of the country population in China is ___________ today as compared with before.A. literaryB. liberalC. literalD. literate35. Having a cup of tea while reading the newspaper is one of my favorite ___________.A. mannersB. occasionsC. timesD. pastimes36. Everyone has his own way of doing things, and I am no __________.A. additionB. expectationC. exceptionD. doubt37. I don’t think the rain will __________ our plan for a picnic.A. impactB. influenceC. affectD. effect38. Richard _________ that his pen must have fallen from his pocket as he was running for the bus.A. consentedB. concludedC. contendedD. contested39. Y ou will learn English in the ________ if you keep on trying.A. finalB. closingC. endD. conclusion40. Mary was so _____________ in writing her novel that she forgot about her dinner cooking in the oven.A. engagedB. attractedC. drawnD. obligedPart 2. Reading comprehension: 40%Passage 1In order to learn to be one’s true self, it is necessary to obtain a wide and extensive knowledge of what has been said and done in the world; critically to inquire into it; carefully to consider it; clearly to analyze it; and earnestly to carry it out.It matters not what you learn, but when you once learn a thing, you must never give it up until you have mastered it. It matters not what you inquire into, but when you once inquire into a thing, you must never give it up until you have thoroughly understood it. It matters not what you try to think of, but when you once try to think of a thing, you must never give it up until you have got what you want. It matters not what you try to carry out, but when you once try to carry out a thing, you must never give it up until you have done it thoroughly and well.If another man succeeds by one effort, you will use a hundred efforts. If another man succeeds by ten efforts, you will use a thousand.41. According to the author, first of all one must ___________.A. analyzeB. inquireC. obtain knowledgeD. act42. When you try to do something, what matters is ___________.A. not to care too much about itB. to act immediatelyC. to think carefully before you do itD. to carry it through to the end43. The end of learning should be ____________.A. thoughB. masteryC. inquiryD. analysis44. According to the author, another man’s success should _____________.A. spur us on to greater effortsB. not be taken into considerationC. make us nervousD. cause one to stop trying45. The author implies but does not say that ____________.A. the way to knowledge is through specializationB. one has to know everything to be successfulC. success depends not so much on natural ability as it does on effortD. success in one’s profession is least important in one’s lifePassage 2Engineering students are supposed to be examples of practicality and rationality, but when it comes to my college education I am an idealist and a fool. In high school I wanted to be an electrical engineer and, of course, any sensible student with my aims would have chosen a college with a large engineering department, famous reputation and lots of good labs and research equipment. But that’s not what I did.I chose to study engineering at a small liberal-arts university that doesn’t even offer a major in electrical engineering. Obviously, this was not a practical choice; I came here for more noblereasons. I wanted a broad education that would provide me with flexibility and a value system to guide me in my career. I wanted to open my eyes and expand my vision by interacting with people who weren’t studying science or engineering. My parents, teachers and other adults praised me for such a sensible choice. They told me I was wise and mature beyond my 18 years, and I believed them.I headed off to college sure I was going to have an advantage over those students who went to big engineering “factories” where they didn’t care if you had values or were flexible. I was going to be a complete engineer: technical genius and sensitive humanist (人文学者) all in one.Now I am not so sure. Somewhere along the way my noble ideals crashed into reality, as all noble ideals eventually do. After three years of struggling to balance math, physics and engineering courses with liberal-arts courses, I have learned there are reasons why few engineering students try to reconcile (协调) engineering with liberal-arts courses in college.The reality that has blocked my path to become the typical successful student is that engineering and the liberal arts simply don’t mix as easily as I assumed in high school. Individually they shape a person in very different ways; together they threaten to confuse, the struggle to reconcile the two fields of study is difficult.46. The author chose to study engineering at a small liberal-arts university because he _______.A. wanted to be an example of practicality and rationalityB. intended to be a combination of engineer and humanistC. wanted to coordinate engineering with liberal-arts courses in collegeD. intended to be a sensible student with noble ideals47. According to the author, by interacting with people who study liberal arts, engineering students can __________.A. balance engineering and the liberal-artsB. receive guidance in their careersC. become noble idealistsD. broaden their horizons48. In the eyes of the author, a successful engineering student is expected __________.A. to have an excellent academic recordB. to be wise an matureC. to be imaginative with a value system to guide himD. to be a technical genius with a wide vision49. The author’s experience shows that he was ___________.A. creativeB. ambitiousC. unrealisticD. irrational50. The word “they” in “… together they threaten to confuse.” (para 5) refers to ____________.A. engineering and the liberal artsB. reality and noble idealsC. flexibility and a value systemD. practicality and rationalityPassage 3The making of glass is a very old industry –at least 4500 years old. Glass has many extraordinary qualities and it is frequently being used in new ways.One of the most interesting new uses for glass is in telephone communication. Scientists have developed glass fibres as thin as human hair which are designed to carry light signals. When the light reaches the other end, it is first changed into electrical signals, which are in turn converted into sound messages.Called light-wave communication, the new system was used successfully in an experiment in Chicago in 1977. During the experiment, two glass fibres were able to carry 672 conversations atthe same time. The light-wave cable, containing 144 glass fibres, has the capacity to carry 50,000 conversations at the same time.The light-wave communication system has two important advantages. First, the glass fibre cables are smaller and weigh less than copper cables. Second, they cost less.51. Perhaps it can be said that telephone communication has entered the age of light!A. sound signalsB. light signalsC. electrical signalsD. any signal52. Before you can hear a message on the telephone using the new system, _______________.A. electrical signals must first be changed into light signals and then into soundB. the light signals have to be changed directly into sound messagesC. light must first be changed into electrical signals and then into soundD. either the light or the electrical signals have to be changed into sound messages53. Which of the following is not included in the passage?A. Glass fibre cables are lighter than copper ones.B. Glass fibre cables are used to carry light waves.C. Light-wave communication has been for civil use of about 30 years.D. Glass is a favorable material for telephone communication.54. From the passage, you can tell that people prefer glass fibre cables to copper cables because ____________.A. glass fibres are less expensiveB. glass fibres deliver messages directlyC. glass fibres are more up to dateD. glass fibres are easier to make55. Which of the following statements best expresses the main idea of the passage?A. Glass is very useful because it has many unusual qualities.B. Light signals have changed the use of glass in industry.C. Glass fibres have reduced the cost of telephone communication.D. The use of glass fibres to carry telephone message is an interesting new development. Passage 4If it were only necessary to decide whether to teach elementary science to everyone on a mass basis or to find the rifled few and take them as far as they can go, our task would be fairly simple. The public school system, however, has no such choice, for the job must be carried on at the same time. Because we depend so heavily upon science and technology for our progress, we must produce specialists in many fields. Because we live in a democratic nation, whose citizens make the policies for the nation, large numbers of us must be educated to understand , to support, and when necessary, to judge the work of experts. The public school must educate both producers and users of scientific services.In education, there should be a good balance among the branches of knowledge that contribute to effective thinking and wise judgment. Such balance is defeated by too much emphasis on any one field. The question of balance involves not only the relation of the natural sciences, the social sciences, and the arts but also relative emphases among the natural sciences themselves. Similarly, we must have a balance between current and classical knowledge. The attention of the public is continually drawn to new possibilities in scientific fields and the discovery of new knowledge; these should not be allowed to turn our attention away from the sound, established materials that form the basis of courses for beginners.56 According to the first paragraph, the task of education is fairly complicated because ________.A. the current public school is too complicated to be understoodB. the public school system has no choice of what to teachC. it is difficult to decide whether elementary science should be taught in public schoolsD. the educators have to take care of both ordinary and gifted students57. The word “defeated” (para 2) most probably means ______________.A. brokenB. beatenC. beatenD. damaged58. Which of the following points is NOT included in the passage?A. One of the major tasks of education is to discover the most promising students.B. In order to teach effectively, educators are requested to lay emphasis on one particular field.C. Some subjects have been over-emphasized in public schools.D. The progress of the society cannot merely rely on inventors.59. It can be inferred from the passage that ____________.A. students should learn more up-to-date knowledgeB. lack of scientific knowledge will lead to poor relations between producers and users of scientific servicesC. students are getting to know the importance of a good balance among the branches of knowledgeD. sufficient attention should be given to basic knowledge60. The best title for this passage might be ___________.A. Balance in EducationB. Education System in Public SchoolC. Current Situation in EducationD. Importance of Teaching Science and TechnologyPart 3: Translate the underlined sentences in the passages above into Chinese 20%英语入学考试(B卷) 答题纸姓名考生单位________________ 得分Part 1 40%1. 2. 3. 4. 5. 6. 7. 8. 9. 10.11. 12. 13. 14. 15. 16. 17. 18. 19. 20.21. 22. 23. 24. 25. 26. 27. 28. 29. 30.31. 32. 33. 34. 35. 36. 37. 38. 39. 40. Part 2 40%41. 42. 43. 44. 45. 46. 47. 48. 49. 50.51. 52. 53. 54. 55. 56. 57. 58. 59. 60. Part 3 20%61.62.63.64.65英语入学考试(B卷答案)DACBD DBABD CADCB ACBAB BBBCD DACCC CCBDD CCCCA CDBAC BDDCA BCCAD DABDA。
衡阳师范学院2011年上学期中文系汉语言文学专业2010级《现代汉语》期末考试试题B 卷一、 填空:(每空1分,共27分。
)1.现代汉民族共同语是以 为标准音,以 为基础方言,以典范的现代白话文著作为语法规范的普通话。
2.普通话声母有22个(包括零声母在内),韵母 个。
3.声调属于语音物理性质中的 现象。
4.舌面单元音的发音主要由舌位的高低、 、 决定。
5.普通话音节结构中韵头有 、、 三个。
6.《汉语拼音方案》正式推行的时间是 ,其内容共分为五个部分,分别为 、 、韵母表、声调符号和隔音符号。
7.语言里能区别意义的最小语音单位是 。
8.汉字的最小构造单位是 。
9.“乃”的笔画数是 ,“乘”的笔顺是 ,10.汉字标准化,要求对汉字进行四定, 、 、定音、定序。
1988年发布的《现代汉语常用字表》中常用字 个,次常用字1000个。
11. 是从古文字演变为现行文字的分水岭。
12.语素是语言中最小的音义结合体。
“哥哥”是个语素,“沙发”是个语素。
13.现代汉语词汇分为基本词汇和一般词汇。
基本词汇有稳固性、性和全民常用性三个特点。
14.现代汉语一般词汇包含有、、外来词、行业语、隐语等。
15.实词都有理性义,还可能有附着在理性义上面的色彩义。
色彩义包括色彩、色彩和形象色彩。
二、判断:(每小题1分,共10分。
)1.普通话的推广是以方言的消灭为前提的。
()2.普通话中一个音节最多可以有四个音素。
()3.声母d、t的主要区别是d为浊辅音,t为清辅音。
()4.韵母iong属于齐齿呼,uan属于合口呼。
()5.ji zhi si中的韵母都是舌面元音 i。
()6.汉字是记录语素的,汉语的语素多是单音节的,所以汉字可以看作是音节文字。
( )7.“椅子”的“子”是词缀,“棋子”的“子”也是词缀。
()8.“下”是一个指事字,“羊”是一个象形字。
()9.“玫瑰”是叠韵联绵词。
()10.“其臭如兰”中的“臭”词义跟今义不同,演变的途径是词义的缩小。
1.很多细胞器上具有质子泵,以下不具有质子泵的细胞器为 (1分)A.内质网 B.溶酶体 C.线粒体D.叶绿体2.生物膜的流动性表现在: (1分)A.膜脂和膜蛋白都是流动的B.膜脂是流动的,膜蛋白不流动C.膜脂不流动,膜蛋白是流动的D.膜脂和膜蛋白都是不流动的,流动性由其它成分决定【解析】膜脂的流动性影响因素:①温度②膜脂的脂肪酸链(不饱和键越多、脂肪酸链越短,膜脂越易流动)③胆固醇(减弱温度对膜脂流动性的影响)④膜脂与膜蛋白的结合程度⑤环境中的离子强度⑥pH 值等运动方式:①侧向扩散②旋转运动③伸缩运动④翻转扩散⑤左右摆动⑥旋转异构运动膜蛋白的流动性影响因素:①膜中蛋白质与脂类的相互作用②内在蛋白与外在蛋白相互作用③膜蛋白复合体的形成④膜蛋白与细胞骨架的作用等运动方式①随机移动②定向移动③局部扩散4.细胞分裂过程中形成的纺锤体其主要成分是:(1分)A.微丝 B.中间纤维 C.微管 D.胶原纤维解析:微丝:真核细胞中均存在,高度保守。
由肌动蛋白分子(表面上有一ATP结合位点)螺旋状聚合成的纤丝(同向排列的双股肌动蛋白丝以螺旋的形式组成),又称肌动蛋白丝,直径约7nm。
微丝和它的结合蛋白(影响组装去组装速度)以及肌球蛋白三者构成化学机械系统。
脊椎动物肌动蛋白分为α、β和γ三种类型。
踏车行为:微丝能被组装和去组装。
当单体上结合ATP时,有较高的相互亲和力,趋向于聚合,当ATP水解,亲和力就会下降则解聚。
微丝的两端组装速度并不一样。
快的一端(+极)比慢的一端(-极)快上5到10倍。
当ATP浓度达一定临界值时,可以观察到+极组装而-极同时去组装的现象,即为“踏车”。
微丝的组装和去组装受到细胞质内多种蛋白的调节,其中封闭蛋白是微丝两端的“帽子”,结合到微丝上时组装和去组装停止。
微丝的功能:1.形成应力纤维,使细胞具有抗剪切力;2.形成微绒毛;3.细胞的变形运动;4.胞质分裂;5.顶体反应;6.其他功能:如细胞器运动、质膜的流动性、胞质环流。
绝密★启用前2011年普通高等学校招生全国统一考试语文(北京卷)本试卷共10页,150分。
考试时长150分钟。
考生务必将答案答在答题卡上,在试卷上作答无效。
考试结束后,将本试卷和答题卡一并交回。
一、本大题共5小题,每小题3分,共15分.1.(3分)下列词语中,字形和加点的字读音全都正确的一项是()A.活性炭韬光养晦冗.(rǒng)长恪.(kè)尽职守B.谐奏曲咄咄逼人怆.(chuàng)然怙恶不悛.(qǔn)C.威慑力暇不掩瑜攫.(jué)取唾.(chuí)手可得D.笑咪咪按图索骥荒谬.(niù)返璞.(pú)归真2.(3分)下列句子中,画线的成语使用正确的一项是()A.这位明星曾带给观众很多快乐,不少“粉丝”竞相模仿他的表演,但这次他因醉酒驾车而触犯法律的行为却不足为训.B.下午,今年的第一场春雨不期而遇,虽然没有电视台预报的降水量大,但还是让京城一直干燥的空气变得湿润了一些.C.伴着落日的余晖,诗人缓步登上了江边的这座历史名楼,极目远眺,晓霞尽染,鸿雁南飞,江河日下,诗意油然而上.D.这本应是一场实力相当的比赛,然而北京国安足球队经过90分钟与对手的激战,却兵不血刃,最终以3:0取得胜利.3.(3分)下列句子中,没有语病的一句是()A.高速公路上交通事故的主要原因是司机违反交通规则或操作不当造成的,交通部门要加强安全宣传,提高司机的安全意识.B.在“人类非物质文化遗产保护行动”中,中国民间文艺家协会确定将抢救民间木版年画列为民间文化遗产抢救工程之一.C.崇安髭蟾是武夷山区特有的两栖类珍稀动物,生活在海拔一千米左右的高山溪水中,最初因五十年前在崇安发现而得名.D.食醋富有氨基酸、钙、磷、铁和维生素B等成分,因此具有美容功效,皮肤吸收之后,可改善营养缺乏,促使皮肤美白细腻.4.(3分)下列有关文学常识的表达,有错误的一项是()A.“胜败兵家事不期,包羞忍耻是男儿.江东子弟多才俊.卷土重来未可知”,这首诗写了与楚汉相争时的项羽有关的事.B.“枫叶四弦秋,枨触天涯迁谪恨;浔阳千尺水,勾留江山别离情”,这幅对联所写的内容与白居易的《琵琶行》相关.C.巴尔扎克是19世纪法国浪漫主义文学家,他所创作的90多部小说,总名为《人间喜剧》,堪称法国社会的“百科全书”.D.海明威是美国现代著名作家,曾获得诺贝尔文学奖,他的代表作有《老人与海》、《太阳照常升起》、《永别了,武器》等.5.(3分)在文中①②横线上填入下列语句,衔接最恰当的一项是()金沙江大峡谷旁有一座远近闻名的纳西古城。
2011年安徽省公务员录用考试《申论》试卷(B类)给定资料【给定资料一】①乡村旅游分为传统乡村旅游和现代乡村旅游两种。
传统的乡村旅游出现在工业革命以后,主要源于一些来自农村的城市居民以“回老家”度假的形式出现,在中国常常把这种传统的乡村旅游归类于探亲旅游。
现代乡村旅游是在20世纪80年代出现在农村区域的一种新型的旅游模式,尤其是在20世纪90年代以后发展迅速。
现代乡村旅游并不以探亲访友为主,旅游的时间也不仅仅局限于假期。
现代乡村旅游可以充分利用农村区域的优美景观、自然环境和建筑、文化等资源,对农村经济的发展发挥重要作用。
它带动了农村产业结构的调整,促进农业综合发展,推进农业的产业化发展。
我国现代乡村旅游始于20世纪80年代后期,但它对于乡村经济的发展,农民增收和社会主义新农村建设却影响深远。
实践证明,大力发展乡村旅游不仅丰富了旅游活动的内容,扩大了旅游容量,而且带动了农村产业结构的调整,加速了农民脱贫致富的步伐,促进了农村经济的发展,为解决“三农”问题和全面建设小康社会提供了一条有效的途径。
中国是农业大国,又是农业古国。
悠久的农业历史,丰富的农耕文化,是发展乡村农业文化旅游的良好基础。
中国是一个多民族的国家,全国有56个民族分布在广大乡村,尤其是西部地区是少数民族集中分布区。
民族风俗、民族文化、民族习惯、民族生活、民族建筑、民族节庆活动等丰富多彩,是发展乡村民俗文化旅游的独特资源。
随着国民经济的发展和城市化进程的加快以及城市居民收入的增加、休假时间的增多、交通条件的改善和人们消费观念的转变,都为发展乡村旅游提供了广阔市场。
目前,我国乡村旅游主要有田园农业旅游模式、民俗风情旅游模式、农家乐旅游模式、村落乡镇旅游模式、休闲度假旅游模式、科普及教育旅游模式与回归自然旅游模式等。
②从大范围看,所有在乡村社区开展的旅游都可以称为乡村旅游,它是与都市旅游相对称的。
乡村旅游与民族旅游、农业旅游、生态旅游关系密切、它较好地适应了人们返璞归真、回归自然的心理需要,特别是对城市居民,长期生活在钢筋混凝土的环境中,工作和生活节奏快、压力大,乡村山清水秀的自然风貌、悠然自得的生活劳动场景、清新的空气、新鲜无污染的绿色饮食等,都具有非常大的吸引力。
淮海工学院11 - 12 学年第 1 学期操作系统原理试卷(B闭卷)一、单项选择题(本大题含20小题,每小题1分,共计20分)答题表(将答案填入下表,否则不予评分)1、操作系统是对()进行管理的软件。
A、软件B、硬件C、计算机资源D、应用程序2、在进程管理中,当()时,进程从运行状态变为就绪状态。
A、进程被调度程序选中B、时间片用完C、等待某一事件发生D、等待的事件发生3、银行家算法在解决死锁问题中是用于()的。
A、预防死锁B、避免死锁C、检测死锁D、解除死锁4、下列步骤中()不是创建进程所必须的。
A、建立一个进程控制块B、为进程分配内存C、将其控制块插入就绪队列中D、为进程分配CPU5、文件系统中用()来管理文件。
A、作业控制块B、外页表C、目录D、软硬件结合的办法6、( )算法是设备分配常用的一种算法。
A、短作业优先B、最佳适应C、首次适应D、先来先服务7、多道程序环境下,操作系统分配资源以( )为基本单位。
A、程序B、指令C、进程D、作业8、在分时系统中,若当前运行的进程连续获得了两个时间片,原因可能是()A、该进程的优先级最高B、就绪队列为空C、该进程最早进入就绪队列D、该进程是一个短进程9、在操作系统中,用户程序申请使用I/O设备时,通常采用( )。
A、物理设备名B、逻辑设备名C、虚拟设备名D、独占设备名10、设3个目标模块A、B、C,起始地址都是0,长度分别是L、M、N,这3个模块按A、B、C顺序采用静态链接方式链接在一起后,模块C的起始地址变换为()。
A、L+MB、L+M+NC、L+M-1D、M+N11、操作系统最重要的特征是()。
A、并发性B、共享性C、虚拟性D、异步性12、以时间换空间的技术是()。
A.分时技术 B.虚拟存储技术 C.并发技术 D.缓冲技术13、某计算机系统中有8台打印机,有K个进程竞争使用,每个进程最多需要3台打印机。
该系统可能会发生死锁的K的最小值是()。
A、2B、3C、4D、514、虚存指的是()。
城市轨道交通系统运营管理(B卷)一、填空(每空1分,计30分)1. 车辆保有数计划包括运用车辆数、在修车辆数、备用车辆数。
2. 运行图编制过程中存在一些实际问题包括商业需求、基础设施能力、列车性能与运行时间、随机干扰、不停站运行。
3. 列车自动控制系统(ATC)包括列车自动防护子系统、列车自动运行子系统、列车自动监控子系统、计算机连锁设备。
4.提高城市轨道交通运行速度有减少加减速时间、减少列车运行时间、减少列车停站时间三种途径。
5. 列车自动防护系统主要用于对列车驾驶进行防护,对与安全有关的设备或系统实行监控,实现列车间隔保护、超速防护等功能。
6. 地铁车站按运营功能可划分为终点站、中间站和换乘站。
7.设备维修一般有全部外协、全部自修、部分外协三种形式。
8.目前在世界的各大城市轨道交通中,香港地铁能做到投资回收,汉城地铁的盈利能弥补投资新加坡地铁和莫斯科地铁能够收支平衡运营。
9. 列车运行图上每个列车均有不同的车号与车次。
二、名词解释(每题4分,计20分)1.长交路、短交路:长交路是指列车在全线各站间运行,为全线提供运输服务,列车到达折返线/站后折返;短交路是指列车在某一区段内运行,在指定车站折返,它可为某一区段旅客提供服务。
2.线路能力:在采用一定的车辆类型、信号设备和行车组织方法条件下,城市轨道交通系统线路的各项固定设备在单位时间内(通常是高峰小时)所能通过的列车数。
3.移动闭塞:闭塞分区长度与位置均不固定,随前方目标点的位置、后续列车的实际速度以及线路参数而不断改变的,与固定闭塞分区相对的移动的闭塞分区。
4.运用车辆数:是指为完成日常运输任务所必须配备的技术状态良好的可用车辆数量。
与高峰小时开行的最大列车对数、列车旅行速度及折返站停留时间有关。
5.全日行车计划:城市轨道交通系统全日分阶段开行的列车对数计划。
其决定着城市轨道交通系统的输送能力和设备(列车)使用计划,也是列车运行图编制的依据三、简答(每题6分,计30分)1. 加强列车折返能力的措施。
2011年0424江苏公务员考试《行测》真题(B卷)第一部分言语理解与表达1、“和谐”是什么?人人都有饭吃,人人都可以说话,就是一种最为朴素的“和谐”,这也是构建和谐社会的题中应有之义。
这段话是说:A、人人有饭吃、可以表达个人看法,是和谐社会的主要特征B、人人有饭吃、可以表达个人看法,是和谐社会的必要条件C、人人有饭吃、可以表达个人看法,是和谐社会的最高标准D、人人有饭吃、可以表达个人看法,是和谐社会的最终目标2、城市化是继工业化以后推动经济社会发展的一个新的重大力量。
地方政府在城市化方面有着很强的冲动,但这个冲动更多表现在土地的城市化方面。
因为土地的升值幅度很大,潜力很大,对地方的经济增长和财政收入也有很大的促进作用。
所以,在城市化进程中,土地的城市化成为地方发展的一个重要手段。
但这并非真正的城市化,因为城市化程度是以人的城市化为标准的。
这段文字的中心意思是:A、发展要避免土地的城市化B、发展要以人的城市化为标准C、人是城市化发展的主要推动者D、城市化是地方发展的正确选择3、一个人买了一个鸟笼放在自家客厅里,过一段时间,他一般会丢掉鸟笼或者买只鸟养。
因为,即使他本人长期面对空鸟笼不感到别扭,可是来访者却不然,几乎所有客人面对空笼子都会产生好奇和疑惑,主人会为必须反复解释而不胜其烦,最后只好丢掉鸟笼或者真的买只鸟回来。
这就是著名的“鸟笼效应”。
对这段话理解错误的是:A、马克思主义唯物辩证法告诉我们,事物是普遍联系的,所以“鸟笼效应”是必然存在的B、挂鸟笼本身不说明什么,但是有了一个鸟笼,主人就有可能买一只鸟与之相配C、“鸟笼效应”是指,大多数时候人们都受制于强大的惯性思维,而缺乏逻辑思维D、鸟笼里应该有鸟是人们的思维定势,人们见到鸟笼就一定会联想到里面应该有鸟4、在我看来,与其说是赵本山的小品受欢迎,还不如说是赵本山的这个人本身更受关注。
自从赵本山登上央视春晚这个大舞台,在陈佩斯等笑星长期缺席的情况下,赵本山和他的“赵家班”几乎成了央视的“金字招牌”,甚至一度成为春晚的收视保证。
2011年杭州市各类高中招生文化考试英语(B卷)五、完形填空(共15小题,计15分)通读下面短文,掌握其大意,然后在各题所给的四个选项(A、B、C和D)中选出一个最佳选项。
主题:Monty的梦想体裁:记叙文难度:★★★★★词数:290 建议用时: 8 mins Monty was the son of a horse trainer. When he was in his ninth grade, he was asked to write a 31 about what he wanted to be and do when he grew up.That night he wrote a seven-page paper saying that someday he’d 32 a horse ranch(牧场). He wrote about his dream in great detail and he 33 drew a picture of a 200-acre ranch with all the buildings.He put a great deal of his 34 into the project and the next day he handed it in 35 his teacher. Two days later he received his paper back. On the front page was a large red F with a 36 that read, “See me after class.”The boy with the dr eam went to see the teacher after class and asked, “37 did I receive an F?”The teacher said, “This is an 38 dream for a young boy like you. You come from a poor family. Owning a horse ranch requires a lot of 39 . You have to buy the land. You have to pay for other things. There is no 40 you could ever do it.” Then the teacher added, “41 you rewrite this paper with a more realistic goal, I will reconsider your grade.”The boy went home and thought about 42 long and hard. He asked his father what he should do. His father said, “Look, son, you have to make up your own mind on this. However, I think it is a very important 43 for you.”Finally, after sitting with it for a week, the boy turned in the 44 paper, making no changes at all. He said to the teacher, “You can keep the F and I’ll keep my 45 .”31. A. speech B. paper C. notice D. diary32. A. paint B. win C. own D. sell33. A. just B. almost C. ever D. even34. A. heart B. life C. advice D. trust35. A. to B. with C. from D. for36. A. word B. letter C. note D. post37. A. How B. Why C. When D. Where38. A. unusual B. unforgettable C. unimportant D. unrealistic39. A. money B. time C. space D. effort40. A. wonder B. way C. problem D. matter41. A. Though B. Since C. Until D. If42. A. himself B. him C. it D. itself43. A. change B. gift C. message D. decision44. A. long B. thick C. same D. correct45. A. grade B. dream C. duty D. secret老师让Monty写一篇关于梦想的文章,他在文章中说他的梦想是拥有一个马场。
全国高校网络教育部分公共基础课统一考试用书大学英语(B)模拟试卷 (2011年修订版)Test 3第一部分:交际用语(共5小题;每小题3分,满分15分)此部分共有5个未完成的对话,针对每个对话中未完成的部分有4个选项,请从A、B、C、D 四个选项中选出正确选项。
1. —Could you help me with my physics, please?—A. No, no way.B. No, I couldn’t.C. No, I can’t.D. Sorry I can’t. I have to go to a meeting right now.2. —Could I speak to Don Watkins,please?—A. I’m listening.B. Oh,how are you?C. Speaking,please.D. I’m Don.3. —Could I borrow your car for a few days?—A. Yes,you may borrow.B. Yes, go on.C. Sure,here your are. Enjoy your journey.D. It doesn’t matter.4. —Thank you for inviting me.—A. I really had a happy time.B. Oh,it’s too late.C. Thank you for coming.D. Oh,so slowly?5. —May I see your tickets,please?—A. SureB. No,you can’t.C. No,they are mine.D. Yes,you can.第二部分:阅读理解(共10小题;每小题3分,满分30分)此部分共有2篇短文,在第一篇短文后有5个正误判断题,从每题后的两个选项中选出正确答案;在第二篇短文后有5个问题。
2011年上海市公务员录用考试《行政职业能力倾向测验》B卷(精选)第一部分言语理解与表达能力言语理解与表达能力部分包括三种类型的题目,均为单项选择题。
每小题给出的4个选项中,只有1项是最符合题意的,请将正确选项选出,并在答题卡上将相应的字母涂黑。
不选或错选,该题均不得分。
(共25题)一、选词填空(1—5题):根据题意,从所给的词语中选出最恰当的词语填入空格内,从而使句子的意思表达得最准确。
请开始答题:1.发展经济________可以为城市文化增加筹码,________文化传承、文化内涵的提升以及文化事业的发展,________不可或缺的,城市的文化含金量如何,并不在于能否造起几幢标志性建筑,而是取决于市民的文化素质。
填入横线处最恰当的一项是()。
A. 不但而且都是B. 虽然但是更是C. 固然不过也是D. 既是那么也是2.诚然,我们的民族经历了难以计数的________,可是中华民族顽强不屈的精气神和自信力从来都没有________过,它犹如一座巍峨壮丽永不倒的万里长城,屹立在中华儿女的心里,并________不绝,纵然历经千年的风雨沧桑。
填入横线处最恰当的一项是()。
A. 内外交困熄灭横亘B. 走投无路消灭耸立C. 山穷水尽绝灭伸展D. 内忧外患泯灭绵延3. 海豚群很快地前前后后________,好像在排队似的________队伍,然后,随着一个不详的信号,它们全都转尾向大海________。
海豚有大的头脑和多皱的大脑皮层,与人脑并无两样。
一般认为,海豚头脑的主要作用在于制造音讯。
在海底视力受限,声音是很好的________方式,而海豚具有不同的传声法。
填入横线处最恰当的一项是()。
A. 游动调整挺进传递B. 游玩调动进发传达C. 游动调整进发传达D. 游玩调动挺进传递4.依次填入下列各句横线处的成语,与句意最贴切的一组是()。
①经过多次试验,嫦娥二号终于突破了四大关键技术。
关键问题一解决,探月工程的其他问题就________了。
1、(唐太宗)皇上与群臣议论怎样禁止盗贼。
有人请求使用严厉的刑法来制止。
皇上微笑的对那官员说:"老百姓之所以去做盗贼,是由于赋税太多,劳役、兵役太重,官吏们又贪得无厌,老百姓吃不饱,穿不暖,这是切身的问题,所以也就顾不得廉耻了。
我应当不奢侈,节省开支,减轻徭役,少收赋税,选用廉洁的官吏,使老百姓穿的吃的都有富余,那么他们自然就不会去做盗贼了,何必要用严厉的刑法呢!"从这以后,过了几年,天下太平,没有人把别人掉在路上的东西拾了据为己有,大门可以不关,商人和旅客可以露宿。
2、今天滁州位于江淮之间,地方偏僻,是船只车辆、商贾游客都很少到的地方。
百姓生下来就不见外地的事情,安心于耕田种地,穿衣吃饭,养老送终。
谁能知道皇上的功德,让百姓休养生息,如雨露滋润、阳光普照达百年之久呢!我来到这里,喜欢它地方僻静而公事清简,又爱它的民风安恬闲适。
既已在山谷间找到这样的甘泉,便每天同滁州的人士来游,抬头望山,低首听泉。
春天采摘幽香的花草,夏天荫凉于茂密的乔木,秋迎风霜,冬赏冰雪。
秋冬的刻削裸露,春夏的清幽秀茂,四时的风光,无一不令人喜爱。
民众也为年年谷物的丰收成熟而高兴,乐意与我同游。
于是为他们推求这里的山川形胜,叙述这里风俗的美好,使民众知道能够安享丰年的欢乐,是因为有幸生于这太平无事的时代。
3、晋平公对师旷问道:“我已经七十岁了,想要学习,但是恐怕已经晚了。
” 师旷回答说:“为什么不把蜡烛点燃呢?” 平公说:“哪有做臣子的人来戏弄君主的呢?” 师旷说:“瞎眼的我怎么敢戏弄君主呢?我曾经听说:少年的时候喜好学习,如同初升太阳的阳光一样;中年的时候喜好学习,就象正午太阳的阳光一样;晚年的时候喜好学习,就像把蜡烛点燃一样明亮,点上蜡烛和在黑暗中走路哪个好呢?” 平公说:“讲得好啊!”4、我来到这里,喜欢它地方僻静而公事清简,又爱它的民风安恬闲适。
既已在山谷间找到这样的甘泉,便每天同滁州的人士来游,抬头望山,低首听泉。
2011第一单元测试卷B高一____班____号姓名____________ 成绩______________ 1.关于信息,以下说法正确的是____。
A. 录音笔可以记录信息B. 数码照相机是一种信息C. 数码摄像机中的记忆磁带是一种信息D. 数码照相机中的存储卡是一种信息2.信息论的创始人香农认为:“信息是能够用来消除____的东西。
”A. 不确定性B. 模棱两可C. 非专业D. 错误3.暑假期间,学校组织部分同学参观上海世博会。
为在开学后能向全校同学展示,同学们决定在参观的同时做好材料的收集工作。
下面的建议中,不属于收集数字化材料的方法是____。
A. 带一个数码相机,将感兴趣的陈列展品拍摄下来B. 带一本笔记本,随时记录参观感受C. 带一支录音笔,可以通过口述录音记录参观经过D. 带一台数码相机,拍摄参观经过4.2010年上海市学业水平考试采用上机操作的形式,为确保考试公平公正,试卷采用电子加密狗的形式进行锁定,只有当本场考试前5分钟才能被软件加载并正常显示。
以下说法中正确的是____。
A. 试题信息不能在考试前公布,表示信息具有传载性B. 试题信息不能在考试前公布,表示信息具有共享性C. 试题信息不能在考试前公布,表示信息具有可处理性D. 试题信息不能在考试前公布,表示信息具有时效性5.下列整数中最小的是____。
A. (10101)2B. (10111)2C. (20)10D. (22)106.某进制数34表示的数值大小为25,则该进制为____。
A.五进制B. 六进制C.七进制D. 八进制7.使用下标表示十六进制数521,以下表示方法中正确的是____。
A. (512)16B. 512HC. 512D. (16)5128.小明同学使用二进制编码,设计了一个上海轨道交通的数字化方案;每个站点的编码分为两个部分,第一部分是所在的线路序号的编码,第二部分是站点序号的编码。
例。
A.001000011B. 001100100C. 001000010D. 0010001009.计算机存储容量最小单位是____,它可以表示一个“0”或者一个“1”。
2011年春季学期《传热学》(B 卷)答案一、(10分)冬天某湖面上结了一层厚度为200mm 的冰,其上、下表面温度分别为-15℃和0℃,冰的导热系数为2W/(m·K),试求通过冰层的热流密度。
如果冰上覆盖了一层厚度为100mm 的雪,雪的导热系数为0.4W/(m 2·K),此时雪的上表面温度为-20℃,试确定此时的热流密度。
解:由公式λδ21t t q -=(3分),代入数据,可得2150m W q =(2分) 当冰上覆盖一层雪时,由串联热阻的叠加公式,有:221131λδλδ+-=t t q (3分) 代入数据,可得214.57m W q =(2分)二、(10分)直径为80mm 、初始温度为25℃的桔子放在冰箱中,冰箱中空气温度为2℃,空气与桔子间表面传热系数为1.5W/(m 2·K)。
已知桔子的物性如下:λ=0.6085 W/(m·K),ρ=997kg/m 3,c=4179J/(kg·K)。
试计算桔子中心温度减低到4℃所需的时间。
解:这是一个典型的非稳态热传导问题,先计算其毕渥数的大小:1.00986.06085.004.05.1<=⨯==λhl Bi ,故可以利用集总参数法计算此非稳态问题。
(3分) 由公式:⎪⎪⎭⎫ ⎝⎛-=--=∞∞τρθθcV hA t t t t exp 00,可得:⎪⎪⎭⎫ ⎝⎛---=∞∞t t t t hA cV 0ln ρτ(5分) 代入数值,可得:88.90452=τs (2分)三、(10分)空气以10m/s 速度外掠0.8m 长的平板,80f t =℃,30w t =℃,计算该平板在临界雷诺数c Re 下的c h 、全板平均表面传热系数以及换热量。
(层流时平板表面局部努塞尔数3/12/1332.0Pr Re Nu x=,紊流时平板表面局部努塞尔数3/15/40296.0Pr Re Nu x =,板宽为1m ,已知5105⨯=c Re ,定性温度C t m 055=时的物性参数为:22.8710W/m K λ-=⨯⋅(),6218.4610m /s ν-=⨯,697.0=Pr )解:(1)根据临界雷诺数求解由层流转变到紊流时的临界长度1552m f w t t t =+=()℃,(1分)此时空气得物性参数为: 22.8710W/m K λ-=⨯⋅(),6218.4610m /s ν-=⨯,0.697r P =5651018.46100.9210c c c Re ulRe X m u νν-⨯⨯⨯=⇒===() (2分) 由于板长是0.8m ,所以,整个平板表面的边界层的流态皆为层流⇒==3/12/1Pr Re 332.0λhlNu x 21/21/351/21/322.87100.3320.3325100.6977.41W/m 0.8c c h Re Pr l λ-⨯==⨯⨯⨯=⋅()(℃) (2分)(2)板长为0.8m 时,整个平板表面的边界层的雷诺数为:561033.41046.188.010⨯=⨯⨯==-νul Re (1分) 全板平均表面传热系数:21/21/351/21/322.87100.6640.664 4.33100.69713.9W/m 0.8h Re Pr l λ-⨯==⨯⨯⨯=⋅()(℃) (2分) 全板平均表面换热量13.90.818030557.9W f w hA t t Φ=-=⨯⨯⨯-=()()(2分)四、(10分)温度50f t =℃的空气平行掠过一表面温度为100w t =℃的平板表面,平板下表面绝热。
2011年普通高等学校招生全国统一考试英语(北京卷)第一部分:听力理解(共三节,30分)第一节(共5小题;每小题1.5分,共7.5分)听下面5段对话,每段对话后有一道小题,从每题所给的A、B、C三个选项中选出最佳选项。
听完每段对话后,你将有10秒钟的时间来回答有关小题和阅读下一小题。
每段对话你将听一遍。
1.What color T-shirt does the man plan to order?A.RedB. BlueC. Green2.Which section does the man like to read?A.3.A.4.A.5.A.听两遍。
听第66.A.7.A.B.C.听第78.A.9.A.听第810.A.Making an invitation.B.Offering information.C.Asking for permission.11.What time is the woman going to see the dentist this Saturday?A.10:30 a.m.B. 12:30 p.m.C. 4:30 p.m.12.What is the woman going to do after seeing the dentist?A.Clean the house.B.Take a walk by the lake.C.Help Jim with his science project.听第9段材料,回答第13至15题。
13.What makes shoppers tired?A.Queuing for electrically-driven cars.B.Looking for what they want to buy.C.Carrying shopping around.14.What is the problem for building moving walkways in the store?A.The spaceB. The redesignC. The technology15.Where will the computer system send the things shoppers buy?A.To the exit.B.To the shelf.C.To the shoppers’ homes.第三节(共5小题;每小题15分,共75分)第二部分,如识运用(共两题)45分。
广州卫生学校2011-2012学年第二学期《语文》课程期末考试卷(B)卷2011级各专业考核方式:闭卷班别 __________ 姓名__________ 学号__________一、选择题(每题2分,共20分)1.下列各组词语中加点字注音完全正确的一项是( )A.请帖.(tiē)跋.(bá)涉玄奘.(zhàng)蓊蓊..郁郁(wěng)B.忐忑..(mò)..(tǎn tè)麻痹.(bì)袅.(niǎo)娜含情脉脉C.懦.(ruò)夫禅.(shàn)让崇.(cóng)拜残羹冷炙.(zhì)D.须臾.(yí)老聃.(dān)跬.(wā)步浚.(qùn)其泉源2.下列各组词语中没有错别字的一项是()A.冥思苦想忧心冲冲眼花缭乱终成眷属B.忘断忘行栩栩如生水光潋滟众叛亲离C.惟妙惟俏潸然泪下道冒岸然望洋兴叹D.克己复礼墨守成规金石可镂谈笑风生3.下列各句子中画横线的成语使用正确的一项是 ( )A.这位农民作家说,自己爱读书并不是附庸风雅,而是在竞争激烈的社会中生存发展的需要。
B.这个饭店服务之差是有口皆碑的,但因只此一家,只好在这里住宿了。
C.联欢会上,杂技演员们在空中飘来荡去,潇洒自如,一个个惊险刺激的动作让人触目惊心!D.这里的山水风光秀丽,栩栩如生,令人陶醉。
4.下列句子没有语病的一项是 ( )A. 这个坚强的女人永远地告别了人世,享年32岁。
B.父亲多才多艺……对外国文学和影视文学的造诣,足以令专业人士侧目。
C.2003年,在SARS猖獗的非常时期,钟南山院士不但始终站在医疗最前线救死扶伤,还积极奔赴各疫区开展医疗工作,倡导与国际卫生组织之间的密切合作。
D.韩林,人称神弹子,武艺高强,又有侠义心肠,但不幸中年夭折。
5.对下列修辞手法的解释,不正确的一项是 ( )A.谁能想到,我们赖以生存的空气,由地面向上延伸六十到三百公里,也把它的重量狠狠地加在我们身上。
华南农业大学珠江学院期末考试试卷
2010--2011学年度 下 学期 考试科目:概率论与数理统计(信工)
考试年级:__2009__级 考试类型:(闭卷)B 卷 考试时间: 120 分钟 学号 姓名 年级专业
一、单项选择题(本大题共8小题,每小题3分,共24分)。
在每小题列出的四个备选项中只有一个正确,请将答案...代码填写到下列表格
中,错选、多选或未选均无分。
1. 设1()3P A =
,1()2P B =,1
()6
P AB =,则事件A 与B 【 】 A . 互不相容 B . 相等 C . 相互独立 D . 互为对立事件
2. 10件产品中有3件次品,从中随机抽出2件,至少抽到1件次品的概率是【 】
A .
31 B . 52 C . 158 D . 15
7 3.设离散型随机变量X 的分布律为:
{0}0.5,{1}0.3,{2}0.2P X P X P X ======, 则{2}P X <=【 】
A . 0.5
B . 0.8
C . 0.3
D . 1 4. 已知~(0,1)X N ,则=≤≤-}11{X P 【 】
A . 1)1(2-Φ
B . (1)1Φ-
C . 2(1)Φ
D . 0
5. 已知X 服从二项分布(),(~p n
B X ),且()12E X =,()8D X =,则二项分布的参数为【 】
A . 136,3n p ==
B . 2
36,3n p == C . 218,3n p == D . 1
18,3
n p ==
6. 设随机变量X 的概率密度函数为23,01
()0, x x f x ⎧≤<=⎨⎩其他
则)(X E =【 】
A . 1
B .
34 C . 1
2
D . 0 7. 设二维随机向量),(Y X 的联合分布列为
则{1}P X Y +==【 】 A .
61 B . 91 C . 187 D . 9
2 8. 已知随机变量X ,Y 相互独立,且X 在[0,2]上服从均匀分布,Y 服从参数为2的指数分布,则()E XY =【 】 A . 14
B . 1
C . 1
2
D . 2
二、填空题(本大题共8小题,每小题3分,共24分)
请在每小题的空格中填上正确答案。
错填、不填均无分
1. 设,,A B C 为三个事件,则“,,A B C 都发生”这一事件可表示为 。
2. 设1()4P A =
,1()3P B A =,1
()2
P A B =,则()P A B =____________。
3. 某球员进行投篮训练,设各次投篮是否进筐相互独立,且各次进篮筐概率相同,已知该球员的投篮命中率是0.5,则其
3次投篮中至少命中1次的概率为 。
4. 设随机变量X 的分布律为
1242X P
c c
c
,则c =________。
5. 连续型随机变量X 的概率密度为4,
01
()0,
a x x f x ⎧<<=⎨
⎩其它
(0)a >,则
a = 。
6. 设随机变量X (4,0.2)B ,且2
Y X =,则{4}P X ==__________。
7. 设),(Y X 的概率密度为⎪⎩⎪⎨⎧>
>=其它,
021,21,),(32y x y x A
y x f ,则A = 。
8. 设X ]1,0[~U ,)1(~E Y ,且X 与Y 相互独立,则),(Y X 的联合概率密度为 。
三、计算题(本大题共3小题,每小题9分,共27分)
1. 发报台以概率0.7和0.3发出信号“∙”和“-”,由于通信系统存在随机干扰,当发出信号为“∙”和“-”时,收报台分别以概率0.1和0.2收到信号“-”和“∙”。
求收报台收到信号“∙”时,发报台确实发出信号“∙”的概率。
2. 城乡超市销售一批照相机共10台,其中有3台次品,其余均为正品,某顾客去选购时,超市已售出2台,该顾客从剩下的8台中任意选购一台,求:(1)该顾客购买到正品的概率;(2)若已知顾客购买的是正品,则已售出的两台都是次品的概率是多少?
3. 已知某机器生产的零件长度X (单位:厘米)服从参数30.20μ=,0.05σ=的正态分布,按规定,零件长度在30.200.20±内为合格品,试求任取一零件为合格品的概率?(附:(1.5)0.9332Φ=,(2)0.9772Φ=)
四、证明题(本大题共1小题,共7分)
设随机变量),(Y X 的概率密度为⎩⎨⎧+∞
<<+∞<<=+-其它,
00,0,),()(y x Be y x f y x ,求B
并证明X 与Y 相互独立。
五、综合应用题(本大题共2小题,每小题9分,共18分)
1. 某仪器装有三只独立工作的同型号的电子元件,其寿命(单位:h )都服从同一指数分布。
已知其平均寿命为600 h ,求(1)每只元件的寿命的概率密度函数;(2)求仪器使用的最初200 h 内,至少有一只元件损坏的概率。
2. 设某种商品每周的需求量X 是服从区间]30,10[上的均匀分布的随机变量,而经销
商店进货数量为区间]30,10[中的某一整数,商店每销售一单位商品可获利500元;若供大于求则削价处理,每处理1单位多出商品亏损100元;若供不应求,则可从外部调剂供应,此时每1单位调剂商品仅获利300元,为使商店所获利润期望值不少于9280元,试确定最少进货量。
参考资料:
1. 随机变量的X 分布函数(){}F x P X x =≤。