新概念英语第二册课后习题答案详解Lesson 21 练习答案Key to written exercises 1．关键句型练习答案 A …passing planes can be heard(1.2); The airport was built (1.2); it could not be used then(1. 3); a hundred people must have been driven away(11.4-5); this house will be knocked down by a passing plane(11.6-7); I have been offered a large sum of money(1.7) C 1 A message will be sent immediately. 2 All these goods must be sold. 3 I told you the parcel would be received in time. 4 The letter has to be delivered by hand. 5 Your letter must have been lost In the post. 2．难点练习答案 A (sample answers) The dog drove the sheep out of the field. The police drove the crowds back. I drove my car into the garage. B1 home 2 houses 3 house 4 home 3．多项选择题答案
第一节．单项填空，从A,B,C,D四个选项中选出可以填入空白处的最佳选项。（共计15小题，每小题1分，满分15分） 21.---Would you mind if I turned on the TV and watched CCTV news? ---___________. As a m atter of fact, I also like watching CCTV news. A. No, you can’t B. Yes, I do C. No, go ahead D. OK, no problem 22.She talked ______ she saw the accident. But in fact she only heard of it from others. A. so that B. as though C. even though D. once 23.The traffic in our county is very busy, for some main streets _______. A.have been rebuilt B.rebuilt C.are being rebuilt D.are rebuilding 24.Nobody knows what happened _____ her _____ the morning of May 1. A. for; in B . with; on C. to; on D. to; in 25.---I missed the first part of the film.It was really a pity. ---You ______home half an hour earlier. A.should go B.must have gone C.should leave D.should have left 26. The (H1N1) flu ________quickly in Lixin last month. A. spread B. spreads C. traveled D. travels 27. With so much homework _____, Tom has to stay at home. A. to do B. to be done C. done D. doing 28.---- Your daughter looks shy. ----After all, it is the first time that she ____ a speech to the public. A.had made B. has made C. is making D. makes 29.---- I hear Jane has gone to the Holy Island for her holiday. ---- Oh, how nice! Do you know when she ____? A. was leaving B. had left C. has left D. left
Lesson 1 1. b选b最为正确。因为a. d.都与课文内容不符合，也不合乎逻辑；c?的意思是“他们没有注意他”，而作者的意图 并不是想让他们注意他，而是想让他们停止谈话。 所以选 b. 最能表达作者当时心里的感受。 2．c 其余3 个答案都与原句意思不符合。 3．b 因为a. to 不对，可以是He went to the theatre;c. into 也不对，可以是He went into the theatre;d. on 更不符合语法，表示在某一个地方用介词in 或at, in 表示在大的空间，如国家，城市等，at则表示在小的地点或空间，如atthe office, at the theatre 等,所以选b.是正确的。 4. ............................ db. above（在.......... 上方）；c. ahead of （在的前面，在之前）不和behind对应， 也不强调位置的前后顺序。 a. before和d. infront of 都是和behind对应的，都有“在........ 前面”的意思。但in frontof更具体的强调位置，而before则包含更宽泛的意思，即时间上， 空间，次序，登记，重要性方面的“在……前面” 5. c 因为用a. Where, b. why, d. when 提问都不符合逻辑，都不是针对状态提问的，只有How 提问，才能用Angry 回答。 6. ab. they 只做主语；c. their 只能做定语；d. us 虽然可以做宾语，但与前一句意思不符合。 7. da. none 是代词，很少用在名词前面； b. any 只能用在否定句或疑问句中； c. not any 不符合语法，因为前面没有助动词did. 8. ba. chair（椅子）,c. armchair（手扶椅）d. class（班级）这3个选择都和seat的意思不符合。Seat是”座位，座席”的意思。强调的是可供坐下的地方，不是具体的椅子。只有b. place 是seat 的同义词。 9. ab. big（大的）指体积；c. tall（高的）指身材；d. large（大的）指空间和面积。 这 3 个词都与人的年龄无关。只有 a. old 是说明年龄的。 10. ca. sad（悲哀，忧愁的）没有生气的意思；b. unhappy（不幸的，不快乐的）不一定是生气；d. pleased（高兴的）同angry意思相反；只有 c. cross（脾气坏的，易怒的，生气的）与angry 意思相反。 11. cc. stand是bear的同义词，都有忍受的意思。而其他3个选择都没有忍受的意思。 12. ca. clever（聪明的）,b. rude（粗鲁的）,d. kind（仁慈的）这3个都不是rude的反义词， 只有polite（有礼貌的）才是和rude 相对应的反义词，所以选 c. Lesson 2 1. c因为根据课文内容，作者正在吃早饭，他不可能在床上。所以a. 和b.与课文内容不符合，作者强调尽管他起床很晚，已经是中午，但他还在吃早饭，所 以 d. 也不对。 2. d因为只有d.才是Aunt Lucy感到惊讶的原因，其他3个选择都不合乎逻辑。 3. c本句有一个表示经常性动作的时间状语sometimes,所以要用一般现在时。因为主 语是He, 所以它后面的动词要在词尾加s. a. stay 词尾没有加s; b. is staying 是进行时；d. staying 是现在分词；只有 c. stays符合时态和人称。 4. cgo to bed 是固定词组，意思是“就寝” 。 a. in 可以用在stay in bed 之中； b. into 和 d. at 不符合语法和习惯用法，英语中不用into bed, at bed 这样的短语。
1-3 求指数函数()(0,0)at x t Ae a t -=>≥的频谱。 (2)220 2 2 (2) ()()(2) 2(2)a j f t j f t at j f t e A A a j f X f x t e dt Ae e dt A a j f a j f a f -+∞ ∞ ---∞-∞-==== =-+++??πππππππ ()X f = Im ()2()arctan arctan Re ()X f f f X f a ==-π? 1-5 求被截断的余弦函数0cos ωt (见图1-26)的傅里叶变换。 0cos ()0 ωt t T x t t T ?≥的频谱密度函数为 1122 1()()j t at j t a j X f x t e dt e e dt a j a ∞ ∞ ----∞ -= == =++? ?ωωω ωω 根据频移特性和叠加性得： []001010222200222 000222222220000()()11()()()22()()[()]2[()][()][()][()] a j a j X X X j j a a a a j a a a a ??---+= --+=-??+-++?? --= -+-+++-++ωωωωωωωωωωωωωωωωωω ωωωωωωωω
Lesson 2: cdcca bbadc db Lesson 3: cacac bccba bb Lesson 4: dbabb acbca cc Lesson 5: cadbc dabcb bd Lesson 6: dacdd adaba da Lesson 7: bccda cdacb ab Lesson 8: dbbac cbbad bb Lesson 9: cbdaa bbdbb dc Lesson 10: addcb cacac ca Lesson 11: bbbab ccacc bd Lesson 12: ccadd adacd aa Lesson : 13 bdbca bbcaa ad Lesson 14: bcacd bcbcb bb Lesson 15: dbcbc dadcc cb Lesson 16: aadab adadd da Lesson 17: dbbdc cbaac ad Lesson18 : Bdbdb cdcac cb Lesson 19: Adccd bcbca cc Lesson 20: Bcbbc bcacc da Lesson 21 : cdcda cbbad cc Lesson 22: dbddb dacda bb Lesson 23: aaacc addbb ad Lesson 24: baaca acccb ab Lesson 25: cbbab cdbaa da Lesson 26: adcbc ddabd bd Lesson 27: dcddd baddc cc Lesson 28: cdbbc dbdcd ba Lesson 29: bccbd babbb cb Lesson 30: aadab cccda dd Lesson 31: dbaca adabc ac Lesson 32: cccbb cadad bc Lesson 33: dbdac bbccc ac Lesson 34: dabca dcbcb ca Lesson 35: adadd adaba dd Lesson 36: addcd ccbad cc Lesson 37: cbbbb dacdb ba Lesson 38: bcaac bddba dd Lesson 39: dacdd abacc ab Lesson 40: ccbca acbbb bd Lesson 41: aacdc bbada cb Lesson 42: dddbb cddac da Lesson 43: bbaad daccd ac Lesson 44: cbccc bdaba bd
机械工程测试技术课后 习题答案 集团标准化小组：[VVOPPT-JOPP28-JPPTL98-LOPPNN]
第三章：常用传感器技术 3-1 传感器主要包括哪几部分？试举例说明。 传感器一般由敏感元件、转换元件、基本转换电路三部分组成。 如图所示的气体压力传感器。其内部的膜盒就是敏感元件，它的外部与大气压力相通，内部感受被测压力p ，当p 发生变化时，引起膜盒上半部分移动，可变线圈是传感器的转换元件，它把输入的位移量转换成电感的变化。基本电路则是完成上述电感变化量接入基本转换电路，便可转换成电量输出。 3-2 请举例说明结构型传感器与物性型传感器的区别。 答：结构型传感器主要是通过传感器结构参量的变化实现信号变换的。例如，电容式传感器依靠极板间距离变化引起电容量的变化；电感式传感器依靠衔铁位移引起自感或互感的变化。 物性型传感器则是利用敏感元件材料本身物理性质的变化来实现信号变换。例如，水银温度计是利用水银的热胀冷缩性质；压电式传感器是利用石英晶体的压电效应等。 3-3 金属电阻应变片与半导体应变片在工作原理上有何区别？ 答： （1）金属电阻应变片是基于金属导体的“电阻应变效应”， 即电阻材料在外力作用下发生机械变形时，其电阻值发生变化的现象，其电阻的相对变化为()12dR R με=+； （2）半导体应变片是基于半导体材料的“压阻效应”，即电阻材料受到载荷作用而产生应力时，其电阻率发生变化的现象，其电阻的相对变化为dR d E R ρλερ == 。 3-4 有一电阻应变片（见图3-105），其灵敏度S 0=2，R =120Ω，设工作时其 应变为1000με，问ΔR =？设将此应变片接成图中所示的电路，试求：1）无应变时电流指示值；2）有应变时电流指示值；3）试分析这个变量能否从表中读出？ 解：根据应变效应表达式R /R =S g 得 R =S g R =2100010-6120=0.24 1）I 1=1.5/R =1.5/120=0.0125A=12.5mA 2）I 2=1.5/(R +R )=1.5/(120+0.24)0.012475A=12.475mA 图3-105 题3-4图
Lesson 1 1 关键句型练习 A I (1) got (2) very angry (3) . I (1) could not hear (2) the actors (3) . I (1) turned round (2) . I (1) looked at (2) the man and the woman (3) angrily (4) . They (1) did not pay (2) any attention (3) . In the end (6), I (1) could not bear (2) it (3). I (1) turned round (2) again (6) . zI (1) can't hear (2) a word (3)! { I (1) said (2) angrily (4) . zIt (1) is (2) none of your business (3) , { the young man (1) said (2) rudely (4) . zThis (1) is (2) a private conversation (3)!{ B 1 I enjoyed the film yesterday. 2 I listened to the news carefully. 3 The man played the piano well. 4 The children played games quietly in their room yesterday. 5 He opened the door quietly. 6 He left immediately. 7 He planted a tree in the corner of the garden. 8 He read the letter quickly in his office before lunch. 9 I borrowed a book from the library this morning. 10 The cook spoilt the soup. 11 We stay at home on Sundays. 12 There are a lot of people at the bus stop. 13 The little boy ate greedily an apple in the kitchen this morning. 14 She draws beautifully. 15 I like music very much. 16 They built a new school in our village last year. 17 The match ended at four o'clock. 18 She received a letter from her brother last week. 2 1 b 2 c 3 b 4 d 5 c 6 a 7 d 8 b 9 a 10 c 11 c 12 c Lesson 2 2.难点练习答案 1 What a wonderful garden(this is) ! 2 What a surprise( this is) ! 3 What a lot of trouble he is causing! 4 What wonderful actors (they are) ! 5 What a hard-working woman (she is) ! 6 What a tall building (it is) ! 7 What a terrible film (it is) !
新概念英语第二册课后习题答案详解Lesson 22 练习答案 Key to written exercises 1．关键句型练习答案 1 from 2 on 3 in 4 on 5 from 6 from 7 of 8 on 9 from 10 in 11 on…in 12 of 13 in 14 on 15 of 16 of 17 from 18 of…on 19 on 20 of…of 21 of 22 of/from 23 of 24 from 25 in 2 6on 27 on 28 from 29 on 30 in 31 from 32 on 33 on 34 on 35 in 36 from 37 on 38 on 39 in 40 of 41 on 42 on 43 of 44 in 45 in
46 in 47 from 48 of 49 of 50 of 51 on 52 of 53 from 54 in 2．多项选择题答案 1. d 根据课文第4-5行She threw the bottle into the sea. She never thought of it again, 只有d. She didn’t expect anyone to find the bottle 是课文所暗示的内容，其他3个选择都不符合课文实际内容。 2. b 根据课文第6行Both girls write to each other regularly now, 只有b. correspond in the normal way now 与课文实际内容相符合，correspond=write to each other, 其他3个选择都不是课文提及的内容。 3. d 本句中的动词dreamed(梦想) 可以同介词of 或about连用，也可以跟that引导的从句做宾语，但不能跟动词不定式。a. to receive 是动词不定式，不合乎语法；b. to receiving 有语法错误，应该是dream of receiving; c. of receive 有语法错误，应该是of receiving; d. that she would receive 是that 引导的从句，可以做dreamed 的宾语，因此应该选d. 4. d 只有d. the same age as(与……年龄相同)之处是正确的表达方式；而a. the same age with 不符合语法，same 不应该同with 连用，而应该同as连用；b. the same age 后面缺as, 不正确；c. as old 后面也应该有as 才符合语法。 5. b 这个句子是一般过去时形式的疑问句，所以填的动词应该是动词原形，因此只有b. throw 是正确答案。 6. d 只有d. about才能同thought构成短语动词表示“考虑”其他3个都不是正确的表达方式。 7. a 只有a. to one another(互相)最符合语法和习惯用法。 b. the one to the other 虽然语法上讲得通，但意思古够通顺； c. each to other不符合语法，应该是to each other; d. to other 不符合语法。 8. c 只有c. trip(旅行) 是正确的表达方式，与前面的were traveling 的意思相符。 a. sail(航行) 不合乎题目意思；b. travel 不是正确表达方式，可以是went on a journey/trip; d. run(跑) 不是正确的表达方式，也不合乎题目意思。 9. d 只有d. sheet (张) 是正确的表达方式，而其他3个选择a. lump(块，团)，b. bar(条，
新概念英语第一册课后答案 Lesson122 A 1 This is the car which the mechanic repaired yesterday. 2 He is the man whom I invited to the party. 3 These are the things which I bought yesterday. 4 He is the man who came here last week. 5 He is the policeman who caught the thieves. 6 She is the nurse who looked after me. 7 She is the woman whom I met at the party. 8 I am the person who wrote to you. B 1 Who met him? That woman? Yes, she's the woman who met him. 2 Who sat there? That man? Yes, he's the man who sat there. 3 Who made it? That woman? Yes, she's the woman who made it. 4 Who read it? That man? Yes, he's the man who read it. 5 Who shut it? That man? Yes, he's the man who shut it. 6 Who took it? That woman? Yes, she's the woman who took it. 7 Who told me? That man? Yes, he's the man who told me. 8 Who saw me? That woman? Yes, she's the woman who saw me. C 1 Whom did you see? That man? Yes, he's the man whom I saw. 2 Whom did you telephone? That woman? Yes, she's the woman whom I telephoned. 3 Whom did you invited? That man? Yes, he's the man whom I invited. 4 Whom did you to the to the cinema? That man? Yes, he's the man whom I took to the cinema. 5 Whom did you find in the garden? That man? Yes, he's the man whom I found in the garden. 6 Whom did you drive to London? That woman? Yes, she's the woman whom I drove to London. 7 Whom did you hear? That woman? Yes, she's the woman whom I heard. 8 Whom did you remember? That man? Yes, he's the man whom I remembered. Lesson124 A 1 She is the woman I drove to London. 2 That's the film I saw. 3 That's the man I spoke to. 4 They are the thieves the police caught. 5 These are the letters I typed. 6 These are the people you asked me about. B 1 Which man? That man? Yes, that's the man I saw yesterday.
现测课后习题答案 第1章 1. 直接的间接的 2. 测量对象测量方法测量设备 3. 直接测量间接测量组合测量直读测量法比较测量法时域测量频域测量数据域测量 4. 维持单位的统一，保证量值准确地传递基准量具标准量具工作用量具 5. 接触电阻引线电阻 6. 在对测量对象的性质、特点、测量条件（环境）认真分析、全面了解的前提下，根据对测量结果的准确度要求选择恰当的测量方法（方式）和测量设备，进而拟定出测量过程及测量步骤。 7. 米(m) 秒(s) 千克(kg) 安培(A) 8. 准备测量数据处理 9. 标准电池标准电阻标准电感标准电容 第2章 填空题 1. 系统随机粗大系统 2. 有界性单峰性对称性抵偿性 3. 置信区间置信概率 4. 最大引用0.6% 5. 0.5×10-1[100.1Ω，100.3Ω] 6. ± 7.9670×10-4±0.04% 7. 测量列的算术平均值 8. 测量装置的误差不影响测量结果，但测量装置必须有一定的稳定性和灵敏度 9. ±6Ω 10. [79.78V，79.88V]
计算题 2. 解: (1)该电阻的平均值计算如下： 1 28.504n i i x x n == =∑ 该电阻的标准差计算如下： ?0.033σ == (2)用拉依达准则有，测量值28.40属于粗大误差，剔除，重新计算有以下结果： 28.511?0.018x σ '='= 用格罗布斯准则，置信概率取0.99时有，n=15，a=0.01，查表得 0(,) 2.70g n a = 所以， 0?(,) 2.700.0330.09g n a σ =?= 可以看出测量值28.40为粗大误差，剔除，重新计算值如上所示。 (3) 剔除粗大误差后，生于测量值中不再含粗大误差，被测平均值的标准差为： ?0.0048σσ ''== (4) 当置信概率为0.99时，K=2.58，则 ()0.012m K V σ'?=±=± 由于测量有效位数影响，测量结果表示为 28.510.01x x m U U V =±?=± 4. 解： (1) (2) 最大绝对误差?Um=0.4，则最大相对误差=0.4%<0.5% 被校表的准确度等级为0.5 (3) Ux=75.4，测量值的绝对误差:?Ux=0.5%× 100=0.5mV
新概念英语2 习题答案 Lesson 1: bcbdc adbac cc Lesson 2: cdcca bbadc db Lesson 3: cacac bccba bb Lesson 4: dbabb acbca cc Lesson 5: cadbc dabcb bd Lesson 6: dacdd adaba da Lesson 7: bccda cdacb ab Lesson 8: dbbac cbbad bb Lesson 9: cbdaa bbdbb dc Lesson 10: addcb cacac ca Lesson 11: bbbab ccacc bd Lesson 12: ccadd adacd aa Lesson 13 :bdbca bbcaa ad Lesson 14: bcacd bcbcb bb Lesson 15: dbcbc dadcc cb Lesson 16: aadab adadd da Lesson 17: dbbdc cbaac ad Lesson18 : Bdbdb cdcac cb Lesson 19: Adccd bcbca cc Lesson 20: Bcbbc bcacc da Lesson 21 : cdcda cbbad cc Lesson 22: dbddb dacda bb Lesson 23: aaacc addbb ad Lesson 24: baaca acccb ab Lesson 25: cbbab cdbaa da Lesson 26: adcbc ddabd bd Lesson 27: dcddd baddc cc Lesson 28: cdbbc dbdcd ba Lesson 29: bccbd babbb cb Lesson 30: aadab cccda dd Lesson 31: dbaca adabc ac Lesson 32: cccbb cadad bc Lesson 33: dbdac bbccc ac Lesson 34: dabca dcbcb ca Lesson 35: adadd adaba dd Lesson 36: addcd ccbad cc Lesson 37: cbbbb dacdb ba Lesson 38: bcaac bddba dd Lesson 39: dacdd abacc ab Lesson 40: ccbca acbbb bd Lesson 41: aacdc bbada cb Lesson 42: dddbb cddac da
新概念英语第二册课后习题答案详解Lesson 16 练习答案Key to written exercises 1．关键句型练习答案 A The word if has been used four times. C 1 rains 2 will never pass 3 is 4will get 5 enjoys 6 is D…if I listen to the radio…If I do something wrong, don't shout at me. If the house is untidy, don't blame me. If you want me to do something, don't forget to say‘please’. If I am playing a nice game, don't send me to bed. If I ask for something…If it is cold don't put the cat out… 2．难点练习答案 1 pay attention 2 remind 3 are knocking 4 look after 5 Remember me 3．多项选择题答案 1. a根据课文3-4行Traffic police are sometimes very polite.只有a. occasionallyvery polite 同这句话意思接近,所以选a. 2. a根据课文第4-5行During a holiday in Sweden, I found this note on my car,只有a. parked his car in the wrong place and received a polite notefrom the police与课文实际内容相符合,而其它3个都与课文内容不符合. 3. d以if引导的条件句是现在时，主句应该用将来时will. a. will 时态正确，但不符合题目意思，应该用否定形式； b. wouldn't, c. didn't 都不符合时态要求；只有 d. won't 符合时态要求和题目意思。 4. a选a是因为动词let做谓语的时候后面只能跟不带to的动词不定式。其他3个选择都不符合语法。 5. b本句是前一句We welcome you to our city 的另一种表达方式。只有选b. arewelcome 才能使这个句子同前一句意思相同。welcome既可以做动词，也可以做形容词。做动词是“欢迎”的意思，它后面一定要有宾语，做形容词，常做表语意思是“受欢迎的” 6. aNo parking 是“禁止停车”的意思，只有a. Don't leave your car here 同它意思接近。 其他3个选择意思都不够贴切。 b. without parking 没有停车 c. don't stop 别停下来 d. There's no room to park her e. 这里没有停车的地方了。显然跟“禁止停车”意思相差悬殊。 7. d为了说明前一句This note is only a reminder(这张字条只是一个提醒.)的强调语气词only只是,仅仅是.只有选d. nothing more 意思最接近,其他3个选择意思都不对. a. nothing 什么也没有 b. no one 没人 c. nothing extra 没有多余的 d. nothing more 只是, 再没有了. 8. a只有a. district(区)与此同时前一句的area(地区)意思最接近. 而b. country(国家,乡村),c. surrounding(周围环境),d. kingdom(王国)这3个都同area意思不同. 9. d本句需要对前一句you will enjoy your stay(你会过得很快乐)作进一步解释。
新概念英语第二册课后习题答案详解Lesson 9 练习答案 Key to written exercises 1．关键句型练习答案 A 1 We went to the Town Hall on Wednesday evening/ New Year's Eve. 2 The clock would strike twelve in twenty minutes time. 3 The clock stopped at five to twelve. B 1 in 2 On 3 during/ in 4 in 5 at 6 on…in 7 in 8 at…in 9 until C (sample answers) 1 The match will begin at 3 o'clock. 2 They bought their house in 1980. 3 The shop is closed from one till two. 4 The children went to school in the morning. 5 He'll finish school in two years' time. 6 Let's go for a walk in the evening. 7 He went to church on Sunday. 2．难点练习答案 A 1 No, I haven't any/ have no money. 2 No, I didn't go anywhere/ went nowhere in the holidays. 3 No, I didn't buy anything/ bought nothing this morning. 4 No, there wasn't anybody/ was nobody present when the accident happened. B He has no hobbies. He goes nowhere. He sees nobody. He is interested in nothing----except food! 3．多项选择题答案
Key Structures单元测试2答案： A a 1 I enjoyed the film yesterday. 2 My mother went to market. 3 This morning the children asked questions continuously in class. 4 On Sundays we stay at home. 5 This morning I borrowed a book from the library. B 1She rarely answers my letters. 2 The shops always close on Saturday afternoons. 3 We never work after six o′clock. 4 We sometimes spend our holidays abroad. 5 Do you ever buy CDs? B A play- are playing play-.play kick-is kicking run-is running b died left spent bought went stayed listened lent kept lost c I have just receive d has been ther e he has already visited He has just bought has gone d 1 did you buy 2 has never lent 3 Have you burnt 4 . fought 5 have just won e 1 was leaving arrived 2 was working was sitting 3 was walking met 4 was reading heard 5dropped was speaking f went-will∕shall go saw-will∕shall see gave-will give spoke-will speak was-will be enjoyed-will enjoy g 1 I will be ironing the clothes. 2 The train will be arriving in a few. 3 We'll be seeing in the moning 4We will be watching the match. 5 He will be correcting exercise. h
西安理工研究生考试 传 感 器 与 智 能 检 测 技 术 课 后 习 题
1、对于实际的测量数据，应该如何选取判别准则去除粗大误差？ 答：首先，粗大误差是指明显超出规定条件下的预期值的误差。去除粗大误差的准则主要有拉依达准则、格拉布准则、t检验准则三种方法。准则选取的判别主要看测量数据的多少。 对于拉依达准则，测量次数n尽可能多时，常选用此准则。当n过小时，会把正常值当成异常值，这是此准则的缺陷。 格拉布准则，观测次数在30—50时常选取此准则。 t检验准则，适用于观察次数较少的情况下。 2、系统误差有哪些类型？如何判别和修正？ 答：系统误差是在相同的条件下，对同一物理量进行多次测量，如果误差按照一定规律出现的误革。 系统误差可分为：定值系统误差和变值系统误差。 变值系统误差乂可以分为：线性系统误差、周期性系统误差、复杂规律变化的系统误差。判定与修正： 对于系统误差的判定方法主要有： 1、对于定值系统误差一?般用实验对比检验法。改变产生系统误差的条件，在不同条件下进行测量，对结果进行比较找出恒定系统误差。 2、对于变值系统误差：a、观察法：通过观察测量数据的各个残差大小和符号的变化规律来判断有无变值系统误差。这些判断准则实质上是检验误差的分布是否偏离正态分布。 b、残差统计法：常用的有马利科夫准则（和检验），阿贝-赫梅特准则（序差检验法）等。 c、组间数据检验正态检验法 修正方法： 1.消除系统误差产生的根源 2.引入更正值法 3.采用特殊测量方法消除系统误差。主要的测量方法有：1）标准量替代法2）交换法3）对称测量法4）半周期偶数测量法 4.实时反馈修正 5.在测量结果中进行修正 3、从理论上讲随机误差是永远存在的，当测量次数越多时，测量值的算术平均值越接近真值。因此，我们在设计自动检测系统时，计算机可以尽可能大量采集数据，例如每次采样数万个数据计算其平均值，这样做的结果合理否？ 答：这种做法不合理。随机误差的数字特征符合正态分布。当次数n增大时，测量精度相应提高。但测量次数达到一定数Id后，算术平均值的标准差下降很慢。对于提高精度基本可忽略影响了。因此要提高测量结果的精度，不能单靠无限的增加测量次数，而需要采用适当的测量方法、选择仪器的精度及确定适当的次数等几方面共同考虑来使测量结果尽可能的接近真值。 4、以热电阻温度传感器为例，分析传感器时间常数对动态误差的影响。并说明热电阻传感器的哪些参数对有影响？ 答：1、对于热电阻温度传感器来说，传感器常数对于温度动态影响如式子t2=t x-T （dtJdt）所示，7■决定了动态误差的波动幅度。了的大小决定了随着时间变化