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21301D/A转换器的参数中，分辨率可以这样理解，DAC的位数越多，能够分辨的最小输出电压变化量就越小，精度就越高。（）
21302D/A转换器的最大输出电压的绝对值可达到转换器外接的基准电源电压值VREF。（）
21303权电阻网络型的D/A转换器，电路简单且便于集成工艺制造，因此被广泛使用。（）
21304下面描述D/A转换器的转换误差的值中表示最小的是（）。
21305如果要求一个D/A转换器能分辨5mV的电压，设其满量程电压为10V，其输入端数字量要10位才够用。
21306一个6bit逐次逼近式A/D转换器，分辨率为0.05V，若模拟输入电压ui =1.8V，其数字输出量的数值为100000。
21307并联比较型A/D转换器的速度最快。
21308双积分型A/D转换器速度慢，但抗干扰能力和精度都高。
21309A/D转换器的二进制数的位数越多，量化单位△越小。（）
21310D/A转换器的最大输出电压的绝对值可达到基准电压VREF。（）
21311在下面3种类型的A/D转换器中，转换速度最高的是（）；转换精度最高的是（）；转换速度与转换精度均较高的是（）。
21312权电阻网络D/A转换器的电路简单且便于集成工艺制造，因此被广泛使用。（）
21313D/A转换器产生转换误差的原因有（）。
21314下面D/A转换器的转换误差最小的是（）。
21315在绝热催化反应器中进行二氧化硫氧化反应，入口温度为 420℃，入口气体中SO2摩尔浓度为7%；出口温度为590℃，出口气体中SO2摩尔含量2.1%， 在催化剂床层内 A，B 两点进行测定：测得 A 点的温度为 620℃ ，测得 B 点的转化率为 80%。请判定结果的可信性。（）
21316在装有球形催化剂的固定床反应器中等温进行某一级不可逆反应，反应物为A，温度为400℃。测得反应物A的浓度为0.005kmol/m3时的反应速率为2.5kmol/（m3床层.min），该温度下以单位床层计的本征速率常数为50s-1，床层孔隙率为0.3， 计算该反应条件下催化剂的内扩散有效因子为（）
21317判断正误：相同的原料及温度条件下，在由两台反应体积均为1m3的串联活塞反应器（工况1）和一台反应体积为2m3的活塞流反应器（工况2）中，分别进行反应A→P。工况1所获的A的转化率较高。（）
21318在绝热活塞流反应器中，进行某气相反应: A B + C，操作压力恒定。反应原料中，组分 A 的摩尔分率为 0.05，其余为惰性组分，进料温度为 850K。反应物的平均比热容为 40k]/(kmol.K)，反应热AHr =140k]/mol，当A的转化率达到 50%时，反应器出口处的温度为（）
21319在活塞流反应器中，1023K 等温下进行下列气相反应A-P+Br=1.2x10-4pa mol/(L.h)进料原料中 A 的摩尔分数为 10%，其余为惰性成分。操作压力为 0.1MPa，则 A的转化率达到 50%，所需的空时为 （）
21320级不可逆反应A - P，ra = 2c kmol/mh。在原料处理量、组成及反应温度等相同条件下，若要求反应至 A 达到相同的转化率，选用以下哪种反应器形式，所需总反应体积最小（）
21321连续釜式反应器的放热或移热 (qs or qr)一T 曲线，如图所示，在点 A、B、C、D 中，属于稳定的定态操作点是（）
21322在串联的全混流反应器中进行某一反应 A P，r = 2c kmol/m3.h。当原料处理量、组成及反应温度等条件下，若要求反应至 A 达到相同的转化率，则串联釜台数越多，则所需的总反应体积 （）
21323The author was writing in the winter from a summer village by the Pacific Ocean.
21324What inventions have really made a difference in the last 150 years？
21325By 1950， the Pacific was no more of a barrier to trade than the Atlantic had been a century earlier.
21326The structure of a resume includes
21327an Application letter can be used as an official request for something， usually in writing， for example，applying for a job， or further studies.
21328"You'll wind up doing a bad job and not surprisingly， will be less keen in future." What does "wind up" mean in this sentence？
21329the theme of Volunteer is about how a volunteer helpled an old lady who felt hopeless to her llife.
21330According to the author， what features does a real hero have？
21331What should a society do if it tries to do away with class structure？
21332Having a first sweetheart is a warm feeling， but thinking about the downs of the relationship can bring much（）to one’s soul.
21333We can make sense that the process of college education is like the formation of a pyramid which is from big to small and from the general to specific.
21334若事务T对资源A加上S锁，则T可以读A，但是不能写A。其它事务能够对A加S锁和X锁。
21335设有两个事务T1、T2，他们对数据A的并发操作如下：－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－；T1 ； T2－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－（1） 请求SLOCK A；读A=18；（2） ； 请求SLOCK A；读A=18
21336若在实体R的诸属性中，属性A不是R的主键，是另一个实体S的主键，则称A为R的（）。
21337If I did what you ask， it would be a（）of everything I believe in.
21338Education is central to a country's economic（）.
21339Admitting you've made a mistake is a sign of（）， not weakness.
21340a.You told me recently that you would come to China.I am looking forward to seeing you both soon.b.Your dinner and hospitality made us feel welcome in this new city.It seemed as if I were your own son.It was unforgettable.c.I was so grateful to you and Mr
21341The motivation for people to participate in extreme sports is to get a rewarD.
21342Which of the following sentences are used for the opening of a recommendation letter？
21343Look.they（）a good time，（）they？
21344Is your father a doctor？Yes， he is.He（）in Town Hospital.
21345It is a good habit to consume foods from each of the five food groups：protein， vegetables，（），（）and（）.
21346A foodie is someone who has a strong interest in fooD.
21347a.Congratulations on being named this year’s Outstanding Student.That’s terrific!b.With all the best wishes.c.I was so happy for you when I saw the announcement on the school website.d.Having studied together for two semesters， I know that you very much d
21348A river（）deep because of its source.
21349Which of the following are components of a thriving friendship？
21350An acquaintance is some one you know very well， you will not only share activities with them， but also share on a very personal level.
21351A nation will（）only when its young people（）.
21352a.A demonstration in our computer programming class will be given by Professor Smith at 1：30 p.m.on Thursday， December 21， in Room 1207 in Classroom Building No.1.b.All other students and teachers of our college are welcome to attend.c.All students and te
21353－－- Dad， when will you be free？ You agreed to go to the seaside with me four days ago.－－- I’m sorry， Jean.But I think I will have a（）holiday soon.
21354A valuable book is just like the best frienD.
21355W.B.Yeats played a major role in the Irish literay revival.
21356The Waste Land， T.S.Eliot' s masterpiece， uses the past as a yardstick to measure the present and underscore what is missing from the present.
21357Sons and Lovers， an autobiographical novel by D.H.Lawrence， deals with a story of a father' s dominant and debilitating love over the sons.
21358Wuthering Heights， the masterpiece of Emily Bront?， narrates the tragic love story of a governess.
21359Dickens took the French Revolution as the background of A Tale of Two Cities， and the two cities are Paris and London.
21360The critical realists criticised the capitalist social system from a proletarian point of view.
21361Who defined novel as a genre？
21362（）refers to a lyric poem lamenting a dead friend， or a public figure.
21363Gulliver' s Travels is the most enduring work by Jonathan Swift， which is a savage satire in the form of a fabulous travelogue.
21364（）is a nine-line stanza of eight lines of iambic pentameter plus an iambic hexameter.
21365William Shakespeare had produced 154 sonnets in total， and the first 126 sonnets seem to be addressed to a young woman， who possesses extreme beauty.
21366The Faerie Queene， fusing adroitly the strands of legend， fable， and praise of Elizabeth I' s England in iteself， is a masterpiece written by Thomas Wyatt， who introduced sonnet into English poetry.
21367（）refers to a long narrative poem celebrating the great deeds of some legendary heroes.
21368The Canterbury Tales is a masterpiece by Geoffrey Chaucer， the first preeminent English poet in history.
21369列表a=[2， 4， 6， 8， 10， 12， 14]，则a[3 ：0 ：-1]切出的结果是什么。
21370推导拉压杆横截面上正应力公式σ=N/A时，研究杆件的变形规律是为了确定（）。
21371拉压杆横截面上的正应力公式σ=N/A的主要应用条件是（）。
21372在下图梁中，a≠b，其最大挠度发生在（）。
21373已知矩形截面，AB=2AC=b，长度为l=4b，外力F1=2F2=F，请问A点的应力大小（）
21374已知电路中a电的电位为5V，b点的电位为10V，那么ab两点间的电压Uab=（）。
21375（） Hello，Zhu Hua.I’ll have to return to Canada because I’ve worked here for a year.（） !
21376It was the training（）he had as a young man（）made him such a good engineer.
21377If you had wanted to buy a record， what（）？
21378A body velocity is not constant is said to be accelerateD.
21379Before a problem can be solved， it must be obvious（）the problem itself is.
21380I am afraid he’s more of a talker than a doer， which is（）he never finishes anything.
21381It is still under discussion（）the old bus station should be replaced with a modern hotel or not.
21382与电压源相连的灯形成一个简单的电路。A lamp（）to a voltage source forms a simple circuit.
21383It is our purpose in this section to introduce the basic meaning of the solution of a differential equation.下划线部分在句中做。
21384We show that a discriminatively trained， multi-layer capsule system achieves state-of-the-art performance on MNIST and is（）than a convolutional net at recognizing highly overlapping digits.
21385Convection（对流） is a（）simpler physical process than conduction.
21386It is shown that a concentration on the preservation of routing abilities might damage the preservation of community structure， and vice versa.该句这样排列的主要原因是保持句子平衡。
21387A对B的影响是
21388In this case， the failure point（失效点）corresponds to a factor of safety of 1.划线部分做什么成分？
21389A点的正面投影所表示的坐标分别为（）。
21390若某页面已添加一个Label控件lblMsg，则执行“lblMsg.Text="；<；a href=\"；http://www.microsoft.com\"；>；微软<；/a>；”语句后，页面上显示的内容是（）
21391已知有数组声明：Dim a（-1 to 3，2 to 5） as integer，引用数组元素，正确的是（）
21392甲基橙碱度A=酚酞碱度P-酚酞后碱度M。
21393当A在两相中发生电离、聚合等化学反应时，分配比与分配系数是不同的，分配比是随着萃取条件的变化而变化的。
21394ia和ua中的a跟单韵母a发音基本一致。
21395用A、B两药分别观察治疗某病，每组均观察15人，欲比较两药疗效，应采用（）。
21396欲研究A、B两种方法测定同一批新生儿脐动脉血微量元素含量是否不同，收集了32例经产道自然分娩的足月新生儿，测得其脐动脉血中锌的含量。下列说法中正确的是
21397A.C
21398A.B
21399如图所示的4个个体组成的群体，A基因座位与B基因座位间存在LD。
21400Nereids Thetis was fated to bore a son who would be greater than his father.
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