模拟试卷2 (2)
- 格式:doc
- 大小:188.00 KB
- 文档页数:6
2008 LA物理师模拟试卷(二)一单选题(共120小题,每小题只有一个选项是正确的)1 阿伏加德罗常数NA约为:A 6.022045×1023B 6.022045×1025C 5.022045×1023D 5.022045×1025E 6.022045×10212 原子序数大于()的元素都不稳定。
A 25B 28C 35D 52E 823 ()发生光电效应的概率最大。
A K层B L层C M层D N层E P层4 关于康普顿效应的描述,错误的是:A光子和轨道电子相互作用后,损失一部分能量并改变运动方向,电子获得能量而脱离原子的作用过程称为康普顿效应。
B 在入射X(γ)光子能量一定的情况下,散射光子能量随散射角增大而减小。
C 散射角一定的情况下,散射光子能量随入射X(γ)光子能量增大而增大。
D 散射角一定的情况下,反冲电子动能随入射X(γ)光子能量增大而减小。
E 每个电子的康普顿效益总截面、转移截面和散射截面均与原子序数无关。
5 以水为吸收介质,光电效应占优势的能量段是:A 1-10KevB 10-30KevC 30Kev-25MevD 25Mev-100MevE 100Mev-125Mev6 具有确定质子数和中子数的原子的总体称为:A 原子核B 同位素C核素 D元素 E核电荷素7 带电粒子与核外电子的非弹性碰撞的论述中,不正确的是:A入射带电粒子与核外电子之间的库仑力相互作用,使轨道电子获得足够的能量而引起原子电离B轨道电子获得的能量不足以引起电离时,则会引起原子激发C处于激发态的原子在退激时,会放出γ射线D处于激发态的原子在退激时,释放出特征X射线或俄歇电子E被电离出来的轨道电子具有足够的能量可进一步引起物质电离,此称为次级电离8 描述辐射品质的物理量是:A传能线密度B线性碰撞阻止C质量碰撞阻止D线性衰减系数E质量衰减系数9 如以r表示电离室的半径,则高能X射线的有效测量点位于:A 0.3rB 0.4rC 0.5rD 0.75rE 几何中心10 由自由电子参与导电并形成电流的硅晶体称为()硅晶体。
模拟试卷2一、单项选择题(每题2分,共10分)在每小题列出的四个选项中只有一个选项是符合题目要求的,请将正确选项前的字母填在题后的括号内。
1.对于事件设a,b,以下命题恰当的就是()a.若a,b互不兼容,则a与b也互不兼容b.若a,b兼容,则a与b也兼容c.若a,b互不相容,且概率都大于零,则a与b也相互独立d.若a,b相互独立,则a与b也相互独立2.将一枚骰子投掷两次,记x1、x2分别第一、第二投掷出来的点数。
记:a?{x1?x2?10},b?{x1?x2}。
则p(b|a)?()1125a.b.c.d.34563.设随机变量x与y均服从正态分布,x~n(?,22),y~n(?,52),记p1?p{x2},p2?p{y5},则()a.对任何实数?,都存有p1?p2b.对任何实数?,都存有p1?p2c.只对?的个别值才存有p1?p2d.对任何实数?,都存有p1?p214.设随机变量x1,x2独立,且p{xi?0}?p{xi?1}?(i?1,2),那么下列结论正2确的就是()a.x1?x2b.p{x1?x2}?1c.p{x1?x2}?1d.以上都不恰当25.设x1,x2源自正态总体n(?,2)的容量为2的样本,以下四个无偏估算中较优的就是()1a.13112x1x2x1x2b.442223433x1x2d.4x1x2c.5577二、填空题(每题2分后,共10分后)1.设a,b为随机事件,p(a)?0.5,p(b)?0.6,p(b|a)?0.8,则p(a?b)?2.设离散型随机变量x的分布列为p{x?k}?a(1/2)k(k?1,2,?),则常数a?3.设x的概率密度为f(x)?1?e?x,则d(x)?24.未知随机变量x的密度为f(x)ax0?x?1,则a?其它?025.设随机变量x和y相互独立且都服从正态分布n(0,3),而x1,?,x9和y1,?,y9分别是来自总体x和y简单随机样本,则统计量u?x1x9yy2129服从分布。
贵州省2023年初中学业水平考试(模拟试卷二)数学同学你好!答题前请认真阅读以下内容:1.全卷共6页,三大题共25题,满分150分,考试时间为120分钟.考试形式为闭卷.2.一律在答题卡相应位置作答,在试题卷上答题视为无效.3.不能使用计算器.一、选择题:以下每题均有A 、B 、C 、D 四个选项,其中只有一个选项正确,请用2B 铅笔在答题卡相应位置作答,每题3分,共36分.1.计算(-5)+5的结果是(A )0(B )-10(C )-25(D )-12.下列数学符号中,是轴对称图形的是(A )∥(B )⊥(C )≌(D )∽3.2023数博会于5月26日在贵阳盛大启幕,以“数实相融算启未来”为主题开展相关活动,活动布展规模达60000平方米.60000这个数用科学记数法可表示为(A )60×102(B )6×104(C )6×105(D )0.6×1054.如图,用一个平面分别去截下列水平放置的几何体,所截得的截面不可能是三角形的是5.若二次根式2x 有意义,则实数x 的值可能是(A )-2(B )0(C )1(D )36.如图,在平面内过点A 作直线m ∥l ,可作平行线的条数有(A )0条(B )1条(C )0条或1条(D )无数条7.已知a >3,下列不等式中,不一定正确的是(A )a -3>0(B )a +1>4(C )2a >6(D )am >3m 8.某市招聘教师,规定将笔试和面试成绩按照4∶6计算总分并择优录取.王星本次参加测试的笔试成绩是85分,面试成绩是90分,则王星最后得分为(A )85分(B )87.5分(C )88分(D )90分(A )(B )(C )(D )(第6题)(第11题)(第9题)图①图②9.将四根长度相等的细木条首尾相接,用钉子钉成四边形ABCD ,转动这个四边形,使它形状改变.当∠B =90°时,如图①,测得AC =2;当∠B =60°时,如图②,AC 的长为(A)2(B )2(C )6(D )2210.关于x 的一元二次方程(m -5)x 2+2x +2=0有实根,则m 能取到的最大整数值是(A )2(B )3(C )4(D )511.《九章算术》中记载了一种测量古井水面以上部分深度的方法.如图,在井口P 处立一根垂直于井口的木杆AP ,视线AC 与井口的直径PB 交于点D ,如果测得AP =2米,BP =3.6米,DP =1米,则BC 为(A )3.6米(B )4.2米(C )5.2米(D )7.8米12.二次函数()220y ax ax c a =-+≠的图象过点(3,0),那么方程的解为(A )1321-=-=x x ,(B )1321=-=x x ,(C )1321-==x x ,(D )1321==x x ,二、填空题:每题4分,共16分.13.已知两个变量x 与y 满足112=-y x ,当自变量6=x 时,因变量y 的值是▲.14.转动如图所示的转盘,当转盘停止时,指针落在白色区域的概率是▲.15.关于x 的分式方程22-+x m x =3的解是正数,则m 的取值范围为▲.16.如图,点A (1,0),点B (4,0),点C 从原点出发,沿y 轴正半轴移动,连接AC ,将线段AC 绕点A 顺时针旋转60°得到线段AD ,连接BD ,当线段BD 取最小值时,点C 的坐标为▲.(第14题)(第16题)220-+=ax ax c三、解答题:本大题共9题,共计98分.解答应写出必要的文字说明、证明过程或演算步骤.17.(本题满分12分)(1)如图,数轴上A ,B 两点所表示的数分别是a ,b ,则a ▲0,b ▲0,a -b ▲0;((填“<”或“>”)(2)先化简(m +2)(m -2)-m 2+m ,再从(1)中的数轴上A ,B 之间任取一个你喜欢的整数作为m 的值,代入化简的结果并求值.18.(本题满分10分)伴随网络化发展,网络销售的确给生活带来便利.小红对网上一家电子产品店在今年14-月的电子产品销售总额情况进行数据收集并整理如图①,其中一款平板电脑的销售额占当月电子产品销售总额的百分比如图②.(1)这家电子产品店从1月到4月,电子产品销售总额为多少万元?(2)直接写出这家电子产品店从1月到4月,电子产品每月销售总额的中位数▲;(3)小红通过图②得出结论,这款平板电脑24-月的销售额占当月电子产品销售总额的百分比与1月份相比都下降了;小星通过图②得出结论,这款平板电脑4月份的销售额比3月份有所下降.请判断,小红和小星得出的结论是否正确?若不正确,请说明理由.(第17题)(第18题)图①图②(第19题)如图,AE ,AD 分别是△ABC 的边BC 上的中线和高,已知BE =8.(1)BC =▲,∠DAC +∠C =▲°;(2)若AD =5,AE =AC ,求△ADE 的面积.20.(本题满分10分)“双减”政策颁布后,各校重视了延时服务,并在延时服务中加大了体育活动的力度.某体育用品商店抓住商机,计划购进乒乓球拍和羽毛球拍共300套进行销售,它们的进价和售价如下表:已知购进2套乒乓球拍和1套羽毛球拍需花费120元;购进4套乒乓球拍和3套羽毛球拍需花费270元.(1)求出表格中a ,b 的值;(2)该体育用品商店根据以往销售经验,决定购进乒乓球拍套数不少于羽毛球拍套数的13,若这批体育用品能够全部售完,如何购货才能获利最大?最大利润是多少?21.(本题满分10分)如图,在平面直角坐标系中,点A 坐标为(0,3),过点A 作y 轴的垂线交反比例函数(0)k y k x=>的图象于点B ,连接OB ,△AOB 的面积为6.(1)求反比例函数的表达式;(2)若点C 为x 轴正半轴上一点,请用无刻度的直尺和圆规作出∠BOC 的平分线,与反比例函数的图象交于点D ,并求出点D 的坐标(要求:不写作法,保留作图痕迹).进价售价乒乓球拍(元/套)a 55羽毛球拍(元/套)b 50(第21题)构建几何图形是利用“数形结合”的思想解决代数问题.学习特殊角的三角函数值时,老师让同学们准备一副三角板如图①,利用直角三角形的边角关系直接探究即可得出结论.(1)填写表格中的特殊角的三角函数值;(2)【问题解决】学习特殊角的三角函数值后,老师布置的课后作业是计算tan22.5°的值.【构建图形】如图②,在Rt △ABC 中,∠C =90°,∠ABC =45°,延长CB 到点D ,使BD =AB ,连接AD ,得∠D =22.5°,所以tan22.5°=112211(1)(212)2-===-++-AC CD .【类比探究】计算tan15°的值.(要求,构建图形并写出计算过程)23.(本题满分12分)如图,△ABC 内接于⊙O ,过点B 作⊙O 的切线,交直径DA 的延长线于点E .(1)若∠ACB =26°,则∠BAD =▲°;(2)求证:∠ABE =∠ACB ;(3)若AE =2cm ,BE =4cm ,求⊙O 的半径.(第23题)(第22题图①)(第22题图②)24.(本题满分12分)如图①,抛物线l :c bx x y ++=2与x 轴相交于点A ,B (3,0)两点,且与y 轴相交于点C (0,-3).(1)求抛物线的表达式和顶点坐标;(2)如图②,若抛物线l 沿着直线y =-x 平移,使其顶点落在坐标轴上,直接写出平移后抛物线的表达式;(3)当(2)中平移后的抛物线顶点落在y 轴上时,在x 轴上是否存在一点P (不与原点重合),过点P 作x 轴的垂线分别交平移前后的抛物线于点E ,F ,交直线y =-x 于点G ,使得PF =EG ,若存在,求出点P 的坐标,若不存在,请说明理由.25.(本题满分12分)【问题解决】(1)如图①,正方形ABCD 的对线相交于点O ,过点O 作OE ⊥OF ,分别交AB ,BC 边于点E ,F .在实验与探究中,小红发现通过证明△BOE ≌△COF ,可得OE =OF .请帮助小红完成证明过程;【类比探究】(2)如图②,在矩形ABCD 中,O 为对线BD 上任意一点,过点O 作OF ⊥OA ,交BC 边于点F ,当BC =2AB 时,求证:OA =2OF ;【拓展提升】(3)如图③,在□ABCD 中,O 为对线BD 上任意一点,过点O 作∠AOF =∠BAD .交BC 边于点F ,求证:BC AB OA OF =.图①图②(第24题)图①图②图③(第25题)。
试卷代号:8176 座位号福建广播电视大学2010—2011学年度第二学期期末考试开放教育专业(专科)《英语II(2)》模拟试题2011年6月(请在答题纸上做答,否则无效)第一部分:英语知识运用 (10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的部分有4个选项,请从A、B、C、D四个选项中,选出可以填入空白处的最佳选项,并写在答题卷上。
(每题2分,共10分)1. —What’s the weather like in this area?— _________________.A. Very wellB. It’s rainyC. Yes, it's fineD. That’s all right2. — How are you feeling now?— _________________。
A。
Much better B. It’s OKC。
Thank you D. He’s all right3。
— What time does the train leave?— _________________。
A. On Tuesday B。
In the morningC. At half past fiveD. At night4. — Have you ever been to Tokyo?— _________________。
A。
No, I didn't go there last year B。
No, but I hope to go there next year C。
Tokyo is a busy city D. Yes, I’ll do it next time5. — Could you please tell me how to get to the nearest bus stop?— _________________。
A. It's not sure B。
1.学习《天净沙·秋思》时,为了使学生更好地理解文章所表达的思想,教师列举了表达相同情感的诗作,下列不合适举例的是()(3.0分)A.范仲淹《苏幕遮》B.崔颢《黄鹤楼》C.王维《终南别业》D.孟浩然《早寒江上有怀》参考答案C解析A项,范仲淹的《苏幕遮》是一首描写羁旅乡愁的词。
B项,崔颢的《黄鹤楼》是一首吊古怀乡的佳作。
C项,王维的《终南别业》描写了诗人自得其乐的闲适情趣。
D项,孟浩然的《早寒江上有怀》描写了诗人客居异地时对家乡的无限思念。
?2.教师在讲解“等闲识得东风面,万紫千红总是春”时,让同学们说出其他的描写春天的诗句,以下不适合用来举例的是()(3.0分)A.千里莺啼绿映红,水村山郭酒旗风B.沾衣欲湿杏花雨,吹面不寒杨柳风C.春色满园关不住,一枝红杏出墙来D.黄梅时节家家雨,青草池塘处处蛙参考答案D解析A.B、C三项都是描写春天的景色,D项“黄梅雨”是夏天才会出现的情景。
3.在学习七年级上册语文《行道树》时,学生提出“立在城市的飞尘里,我们是一列忧愁而又快乐的树”这句话中的“忧愁”与“快乐”是相互矛盾的。
下列教师处理中,最为恰当的一项是()(3.0分)A.这怎么可能矛盾呢大家还记得鲁迅有一篇文章中的一句话吧——我家门前有两棵树,一棵是枣树,另一棵也是枣树。
这是一样的道理啊,不矛盾B.大家能在学习中发现问题很好,但是要知道大作家的每一句都是有用的,不要去质疑它,我们只需要学习这种语言智慧就行了C.真的吗再好好考虑考虑,看看自己的思路正确不正确D.矛盾吗大家还记得我们在课文中讲到……(回忆课文中写行道树“忧愁”“快乐”的句子)。
现在大家明白“行道树”是不是既有“忧愁”又有“快乐”了那么这句话是不是不矛盾了参考答案D解析A项虽拓展了知识,但是并没有帮助学生理解这句话,排除。
B项回避了学生的问题,错误。
c项容易误导学生,让学生认为自己的思路不正确,不利于学生的理解,错误。
只有D项结合课文对学生的问题进行解答,有利于帮助学生理解文意。
2022年秋人教版七年级新生入学分班考试数学模拟试卷(2)一.填空题(共8小题,满分22分)1.(2分)一个数,用8、9、18去除,都能整除,这个数最小是.2.(4分)甲、乙两地相距540千米,A、B两辆汽车从甲、乙两地同时出发,相向而行,经过5小时两车相遇。
已知A车的速度是65千米/时。
(1)求相遇时A车行了多少千米,列式为。
(2)求B车的速度,列式为。
3.(2分)横断面是的木材叫做方木.4.(2分)小马虎在计算除法时,把除数13误写成31,结果得到商19还余9,那么正确的商是.5.(2分)一个等腰直角三角形的直角边长2分米,这个三角形的面积是平方厘米。
6.(4分)把5米长的钢筋,锯成每段一样长的小段,共锯6次,每段长米,如果锯成两段需2分钟,锯成6段共需分钟.7.(2分)如图:直角三角形ABC,如果以AC边为轴旋转一周的空间是立方厘米.8.(4分)一个圆与一个长方形的面积相等,圆的半径与长方形的宽都是4cm,那么长方形的长是cm,面积是cm2.二.选择题(共6小题,满分24分,每小题4分)9.(4分)笑笑3分钟打120个字,淘气2分钟打84个字,两个人打字速度相比()A.笑笑快B.淘气快C.一样快10.(4分)母鸡和公鸡一共有24只,其中母鸡的只数是公鸡的2倍,母鸡有()只。
A.16B.8C.411.(4分)一个盒子里装有3双白色袜子,2双蓝色袜子.所有的袜子的型号相同,一个盲人从盒子里摸出一双袜子,摸出白色袜子的可能性是()A.B.C.12.(4分)将3个棱长为4cm的正方体拼成一个长方体,表面积会减少()平方厘米.A.48B.64C.3613.(4分)从1到2000共2000个整数里,是3的倍数但不是5的倍数的数有()个.A.532B.533C.53414.(4分)甲乙丙三人中,只有一个人数学测验没有及格。
甲说:“是丙”;乙说:“甲在说谎”;丙说:“不是我”。
如果三人说的只有一人是对的,那么()没有及格。
全国自考(管理信息系统)模拟试卷2(题后含答案及解析)题型有:1. 单项选择题 2. 填空题 3. 名词解释 4. 简答题 5. 应用题单项选择题1.采取自底向上方法开发系统的主要缺点是( )A.不易适应组织机构的真正需要B.不易发现和理解系统的附加需要C.不易控制和判断系统开发费用D.不易保证系统数据的一致性和完整性正确答案:D解析:自底向上方法的主要缺点是:汇总的系统不一定符合企业的整体目标,系统的数据一致性和完整性难以保持。
故选D。
2.在管理信息系统的结构中,主要进行基础业务处理的子系统是( )A.业务处理子系统B.执行控制子系统C.管理控制子系统D.战略计划子系统正确答案:A解析:业务处理子系统主要进行基础业务的处理,比如说打字、算账、造表等工作。
故选A。
3.下列关于决策支持系统的描述不正确的是( )A.支持非结构化和半结构化决策B.所处理的问题大部分属于结构化问题C.能够为决策者提供各种备选方案D.以管理科学、运筹学、控制论和行为科学为基础正确答案:B解析:决策支持系统是以管理科学、运筹学、控制论和行为科学为基础,以计算机技术、仿真技术和信息技术为手段,支持非结构化和半结构化决策的信息系统,所处理问题大部分属于半结构化性质的。
故选B。
4.下列不属于管理信息系统技术平台的是( )A.管理组织机构B.数据库管理系统C.操作系统D.服务器正确答案:A5.下列选项中,属于应用软件的是( )A.图像处理软件B.语言处理程序C.系统维护软件D.数据库管理系统正确答案:A解析:应用软件是用于完成用户所要求的数据处理任务或实现特定功能的程序,如文字处理软件、表格处理软件、图形图像处理软件等。
故选A。
6.企业系统规划法制定管埋信息系统规划的依据是企业的( )A.规模B.目标C.现状D.管理正确答案:B解析:企业系统规划是根据企业目标制定MIS规划的结构化方法。
故选B。
7.在系统开发过程中,对现行系统的详细调查属于( )A.系统规划B.系统设计C.系统分析D.系统实施正确答案:C8.在系统详细调查的方法中,适合于对系统定性调查的方法是( ) A.问卷调查B.开调查会C.研究资料D.发电子邮件正确答案:B解析:开调查会是一种集中征询意见的方法、适合于对系统的定性调查。
高考英语上海卷模拟试卷(二)考生注意:1.考试时间120分钟,试卷满分140分。
2.本考试设试卷和答题纸两部分。
第I卷(共90分)I. Listening Comprehension (25 分)Section A (每题1分,共10分)Directions: In Section A, you will hear ten short conversations between two speakers. At the end of each conversation, a question will be asked about what was said. The conversations and the questions will be spoken only once. After you hear a conversation and the question about it, read the four possible answers on your paper, and decide which one is the best answer to the question you have heard.II. Grammar and Vocabulary (每题1 分,共20 分)Section ADirections: After reading the passage below, fill in the blanks to make the passage coherent and grammatically correct. For the blanks with a given word, fill in each blank with the proper form of the given word; for the other blanks, used one word that best fits each blank.An implant that can cool nerves to block pain signals has been unveiled by researchers who say the device could offer an alternative to drugssuch as opioids (类鸦片活性肽).The team behind the device say it could bring benefits for management of acute pain such as (21)_______ experienced after amputations (截肢)or nerve grafts."We are optimistic that this represents a very promising starting point for an engineering approach (22)_______ treating pain,” said Prof John Rogers of Northwestern University in the US, a co-author of the research. But he cautioned that it might be some time (23) _______ they were available to patients. "As with any implantable device, the regulatory process can be slow, typically (24) _______ (involve) much more extensive animal model studies over a period of years," he said.Writing in the journal Science, the team report that the device to block pain signals, which (25) _______(test) only on rats so far, involves a pump, external control system and an implant made from a soft, rubbery substance. The latter forms a sealed collection of tiny channels which form a twisting path in the part of the implant that sits around the target nerve like a cuff.When liquid coolant and dry nitrogen flow through the implant, the liquid causes a drop in temperature. An electronic sensor in the device allows the temperature at the nerve (26) _______(keep) constant."All body processes are based on metabolic chemical reactions, motions of ions and flows of fluids--all (27) _______slow down as a result ofcooling,” said Rogers. “ The net effect when cooling is applied to a nerve is in blocking of electrical signals."Among their experiments, the team tracked two rats with an injury, recording over a three- week period the minimum force that (28)_______be applied to the hind paw to cause the animal to retract (缩回)it. This data was then compared against three rats who were similarly injured but also had the implant. The results suggest bouts of cooling of the injured nerve from 37℃ to 10℃led to (29) _______(severe) pain, with a sevenfold increase in the force that could be applied to the paw. The team say the implant’s benefits include (30)_______, in contrast to opioids, it is not addictive. As the implant is made with water-soluble and biocompatible materials, it can break down in the body after use. The implant could be inserted as an extension of the patient’s initial surgery.Section BDirections: Complete the following passage by using the -words in the box. Each word can only be used once. Note that there is one more word than you need.A. attachedB. bottle-fedC. confusionD. invisibleE. originallyF. orphanedG. partneringH. procedureI. reproducedJ. subjectsK. unintentionallySaving Baby BearsReacting to the auditory assault of barking dogs, shouts and rifle blasts, a 168-pound American black bear shot out and hightailed (迅速逃走)it into the woods off a logging road.His sister, weighing in at 135 pounds, took a little more time to overcome her fear and (31) _______ before she, too, ran for the trees and away from the humans who had driven more than 100 miles to witness the bears’ return to the wild.The cubs were the 106th and 107th (32) _______ or injured bears to be raised or treated at the Progressive Animal Welfare Society (PAWS) Wildlife Center in Washington state, then released months later in the same general area where they were (33) _______found. Fitted with GPS collars and tattooed with identification numbers on their gums, the bears are also among the latest (34) _______of a long-term research study being conducted by Rich Beausoleil and Lindsay Welfelt, both biologists and bear and cougar specialists.The siblings were only two weeks old when a forest worker and his dog (35) _______ disturbed their den in February 2020, scaring away their mother. She never returned.The worker contacted the WDFW, an agency (36) _______with PAWS to rehabilitate sick, injured wild animals before releasing them back into their natural habitats."Their eyes and ears weren't open, and their teeth hadn't evenerupted,Jennifer Convy, PAWS senior director of wildlife, said of the cubs, which each weighed less than 2 pounds when they arrived and were the youngest ever to be raised at the center.Though (37) _______at first, the cubs weren't cuddled. Instead, their caregivers wore bear- scented bear suits during feedings once the cubs' eyes had opened. At PAWS, the staff and volunteers take pains to be (38)_______to all the animals in their care."They don't see us, ever. We don't talk to them. We don't name the animals because we don't want our staff or volunteers to get (39)_______,“ Convy said. After more than a year, the bear siblings were released.The wildlife biologists are studying how the bears raised at PAWS fare after their release, compared to their wild-reared brethren. One cub released in 2017 had her first litter of cubs in January."We've been to her den several times." Beausoleil said. "She (40)_______ and had cubs of her own ... This was kind of a turning point for us."After all, the whole point of PAWS' rehabilitation "is to protect and perpetuate (使持续) the species," he said.III. Reading Comprehension (45 分)Section A (每题1分,共15分)Directions: For each blank in the following passage there are four wordsor phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.The Other da Vinci CodeFor centuries, two of the most intriguing questions about Leonardo da Vinci's "Mon a Lisa" were "Who " and "When ”A(n) (41) _______made at Heidelberg University in 2005 pretty much answered both. A note written in a manuscript in the library (42) _______the account of da Vinci's first biographer, Giorgio Vasari: that the sitter was a merchanfs wife, Lisa Gherardini. The note also helped date the masterpiece to between 1503 and 1506.A(n) (43)_______ mystery-"Where "- is still in dispute. But on June 3rd a French engineer, Pascal Cotte, declared that he and a collaborator had (44) _______the landscape in the background of the painting. Arguments had (45)_______ been made for stretches of countryside in the Marche region and between Milan and Genoa. During a presentation in Vinci, near Florence, Mr Cotte maintained that the artist was more plausibly depicting a part of his native Tuscany 一one that keenly interested him at the time. According to this theory, da Vinci represented the area not as it was, but as, in an unrealised scheme, he (46) _______ it to be.Mr Cotte, who was asked by the Louvre (where the "Mona Lisa" hangs) to create a digital image of the painting, is the inventor of themultispectral camera: a device that can detect not only the drawing below the (47) _______of an oil painting, but also, where they exist, intermediate layers of work. It was among these, under what appears to be a pointed rock, that he found a(n) (48) _______sketch showing that da Vinci meant it to represent a castellated tower.The landscape of the "Mona Lisa" also includes a huge overhanging cliff. That is (49)_______ to one that da Vinci included in a sketch of a fortress (堡垒)contested by Pisa and Florence in the war that flared between them in 1503 (around the time he was painting Gherardini). The (50)_______ with the nearby cliff ——and a tower, known as the Caprona tower 一all overlook the river Amo as it snakes from Florence to Pisa. All three also feature in drawings made by da Vinci to illustrate a plan about which, says Mr Cotte, he became “(51) _______”.This involved diverting the Amo to (52) _______Pisa's water supply and give Florence an outlet to the Mediterranean. In the early 1500s, with the two citystates at war, the idea was under active consideration. Mr Cotte argues that a(n) (53) _______ winding through desolate countryside at the right of the "Mona Lisa" is too wide to be a road, as some have speculated, and is(54) _______the driedup bed of the Amo as da Vinci envisaged (设想)it once his plan had been adopted.It never was. But if Mr Cotte's theory is right, it might just explain why Gherardini, a Florentine, exhibits such a contented, if mysterious, (55)_______。
广东海洋大学
《 数字信号处理 》课程模拟试题
课程号:
■ 考试
□ A 卷
■ 闭卷
一、 填空题(每空2分,共10分)
1. N=210点的基2FFT 需要__8__级蝶形运算。
2. 一个线性时不变系统在Z 域上因果稳定的条件是系统函数的收敛域 为半径小于1的圆的外部。
3. 欲借助FFT 算法快速计算两有限长序列的线性卷积,则过程中要调用__3__次FFT 算法。
4. 满足第一类线性相位滤波器αωωφ-=)(,系统的群时延为2
1
-=
N α。
5. 窗函数法设计FIR 滤波器,采用布莱克曼窗设计滤波器阻带衰减最大。
二、 选择题(将正确答案填到括号里,每题2分,共20分) 1. 不属于数字信号处理具有的优点是( C )
A. 精度高
B.可以实现多维信号处理
C. 应用的频率范围受限
D.灵活性强,可以实现模拟系统很难达到的指标
班级:
姓
名:
学号:
试题共 4
页
加
白纸 3 张
密
封
线
GDOU-B-11-302
2.采样序列在( A )上的Z 变换等于其理想抽样信号的傅里叶变换。
A.单位圆 B.实轴 C.正虚轴 D.负虚轴
3. 若一模拟信号为带限,且对其抽样满足奈奎斯特条件,则只要将抽样信号通过( A )即可完全不失真恢复原信号。
A.理想低通滤波器 B.理想高通滤波器 C.理想带通滤波器 D.理想带阻滤波器
4. 已知序列Z 变换的收敛域为12
1<<z ,则该序列为( D )。
A.有限长序列 B.右边序列 C.左边序列 D.双边序列
5. 下列各种滤波器的结构中哪种不是IIR 滤波器的基本结构( D )。
A.直接型
B.级联型
C.并联型
D.频率抽样型 6.下列序列中属周期序列的为( D )。
A. x(n)=δ(n) B. x(n)=u(n) C. x(n)=R 4(n) D. x(n)=1
7. 设两有限长序列的长度分别是M 与N ,欲用循环卷积计算两者的线性卷积,则循环卷积的长度至少应取( B )。
A. M+N
B. M+N-1
C. M+N+1
D. 2(M+N) 8. 线性相位FIR 滤波器主要有以下四类,其中不能用于设计高通滤波器的是( B C )。
A.h(n)偶对称,长度N 为奇数
B.h(n)偶对称,长度N 为偶数
C.h(n)奇对称,长度N 为奇数
D.h(n)奇对称,长度N 为偶数 9.( A )滤波器的幅度特性在通带和阻带段均为等波纹。
A. 椭圆
B. ChebyshevI
C. ChebyshevII
D. Butterworth 10. 设点数为4 的序列x(n)=2nR 4(n),y(n)为x(n)的循环移位:y(n)=x((n-5))N R N (n),则y(3)=( C )
A. 0
B. 2
C. 4
D. 6 三、 判断题(每题2分,共10分,正确的打√,错误的打⨯)
1.( √ )FIR 滤波器较之IIR 滤波器的最大优点是可以方便地实现线性相位。
2.( × )双线性变换法不适合设计高通数字滤波器。
3.( × )级联型结构不可以单独调整极点位置。
4.( × )双线性变换将S 平面的左半平面映射到Z 平面的单位圆上。
5.( √ ) FFT 可以计算FIR 滤波器,以减少计算量。
四、简单计算与作图(每题6分,共36分)
1. 画出8点按时间抽取的基2FFT 算法的运算流图。
并计算其复数乘法和复数加法的次数。
(见课本96~97页)
2.试讨论正弦序列:)sin()(0φω+=n A n x 的周期性。
(见课本14页)
3. 求序列)]5()([3.0)(--=n u n u n x n 的z 变换、收敛域、画出零极点分布图。
∞≤<--=
==
--=-∞
-∞
=-∑∑z z z z
z
n x z X n n
n
n n
03.01)3.0(13.0)()(1
5
14
4. 写出下列网络结构的系统函数及差分方程,说明该系统是否稳定,为什么?
-1
X(n)
-1
2
1
)()2()1()()(--++=-+-+=cz
bz a z H n cx n bx n ax n y
该系统稳定,因为此滤波器是FIR 滤波器,系统函数的极点在原点,符合系统稳定的条件。
5. 用矩形窗设计线性相位的低通滤波器⎩⎨⎧≤≤-=-其它
,0,)(π
ωωωαω
c j j
d
e e H
51,
5.0==N c πω,写出h(n)表达式,确定α与N 的关系
(参考课本210页及第7章的作业)
6. (此题可不看)频率采样法设计一个FIR 数字低通滤波器其理想特性为
()
⎩
⎨
⎧≤≤≤≤=πωππ
ωω
5.005.001j d e
H ,采样点数 N=16,要求线性相位,求出其幅度采样值H k 。
五、计算题(每题12分,共24分) 1. 如图所示的RC 低通滤波器
(1)用脉冲响应不变法转换成数字滤波器。
并画出相应的网络结构图 (2)用双线性变换法转换成数字滤波器。
并画出相应的网络结构图 (3)以上两种方法所设计的滤波器各自存在那种失真?
模拟RC 滤波器的频率响应函数为
ΩC R ΩC
ΩH a j 1j 1)(j +
=
可以得出对应的系统函数为
利用脉冲响应不变法转换,数字滤波器的系统函数H 1(z )为
利用双线性变换法转换,数字滤波器的系统函数H 2(z )为
令T
RC T RC
b T RC a 2121,211+
-
=+=
y(n)
RC
e
-
j 11
()(j )11
a a Ωs sC
RC
H s H ΩR s sC RC
====++
11
11/1)(--
-=z e RC
z H T RC
11
1
2211
11()()
22(1)(1)a z s T z
z H z H s RC RC z T T
----=-++==+
+-
2. 序列)3(2)2()(2)(-+-+=n n n n x δδδ,)3(2)1(2)()(-+-+=n n n n h δδδ,求 (1)它们的线性卷积
x(n)={2,0,1,2} h(n)={1,2,0,2} y(n)=x(n)*h(n)={2,4,1,8,4,2,4}
(2)它们的循环卷积(序列长度N=6),简述循环卷积和线性卷积的关系。
循环卷积为:{6,4,1,8,4,2}
当循环卷积长度N ≥N1+N2-1时,循环卷积与线性卷积相等。