慕课标签存档

第二周 美国简史

单元测验一

1、单选题：
‌四川大学的校训是？‎
选项：
A: 海纳百川 有容乃大  
B: 自强不息 厚德载物
C: 诚朴雄伟 励学敦行 
D: 德才兼备 知行合一
答案: 【 海纳百川 有容乃大  】点我阅读全文

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第一周1绪论、投影法及多面正投影；2制图的基本知识和技能

圆弧连接

1、判断题：
‏1.平面图形的定位尺寸必须标注两个（       ）‏‏‏
选项：
A: 正确
B: 错误
答案: 【 错误】点我阅读全文

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Chapter 10 Lipid metabolism

Test for Chapter 10

1、单选题：
What is the acyl carrier for the de novo synthesis of fatty acids? ‍
选项：
A: ACP
B: CoA 
C: Biotin
D: TPP
答案: 【 ACP】点我阅读全文

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第四周 中央银行制度的形成与发展2

单元测验

1、单选题：
‏（）的中央银行是无资本金的特殊法人。‎
选项：
A: 日本
B: 韩国
C: 意大利
D: 澳大利亚
答案: 【 韩国】点我阅读全文

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第一讲 计算文化

随堂小测验

1、单选题：
‍计算机病毒是【 】点我阅读全文

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引 言 中国文学现代化的发生

引 言 测验

1、单选题：
‏严复翻译的《天演论》出版于             年。‍
选项：
A: 1904
B: 1897
C: 1898
D: 1902
答案: 【 1898】点我阅读全文

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第1章 控制系统的状态空间表达式

第1章 单元测试

1、单选题：
‍下列关于非奇异线性变换说法错误的是（）‍
选项：
A: 同一系统不同状态向量之间存在非奇异线性变换关系；
B: 合理地选取非奇异变换矩阵一定能将系统矩阵化为对角规范型；
C: 非奇异线性变化不改变系统的特征值；
D: 非奇异线性变换不改变系统传递函数矩阵；
答案: 【 合理地选取非奇异变换矩阵一定能将系统矩阵化为对角规范型；】点我阅读全文

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第1讲 茶道概述

第1讲 茶道概述 测试题

1、单选题：
‏茶道起源于哪个国家？‏
选项：
A: 中国
B: 日本
C: 韩国
D: 印度
答案: 【 中国】点我阅读全文

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第1周第一章绪论

自动控制绪论

1、单选题：
‍自动控制理论的发展进程是（    ）。​
选项：
A: 经典控制理论、现代控制理论、智能控制理论    
B:  经典控制理论、现代控制理论
C: 经典控制理论、现代控制理论、模糊控制理论
D: 经典控制理论、现代控制理论、模糊控制理论、神经网络控制、专家控制系统
答案: 【 经典控制理论、现代控制理论、智能控制理论    】点我阅读全文

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Lesson 2

Scanning

1、单选题：
‎Read the passage "The Discovery of X-rays" quickly and choose the paragraph(s) which contain(s) the answer(s). You may choose more than one answer for question 3. ‍‎‍The Discovery of X-rays‍‎ ‍Par. 1 Except for a brief description of the Compton effect, and a few other remarks, we have postponed the discussion of X-rays until the present chapter because it is particularly convenient to treat X-ray spectra after treating optical spectra. Although this ordering may have given the reader a distorted impression of the historical importance of X-rays, this impression will be corrected shortly as we describe the crucial role played by X-rays in the development of modern physics.‍Par. 2 X-rays were discovered in 1895 by Roentgen while studying the phenomena of gaseous discharge. Using a cathode ray tube with a high voltage of several tens of kilovolts, he noticed that salts of barium would fluoresce when brought near the tube, although nothing visible was emitted by the tube. This effect persisted when the tube was wrapped with a layer of black cardboard. Roentgen soon established that the agency responsible for the fluorescence originated at the point at which the stream of energetic electrons struck the glass wall of the tube. Because of its unknown nature, he gave this agency the name X-rays. He found that X-rays could manifest themselves by darkening wrapped photographic plates, discharging charged electroscopes, as well as by causing fluorescence in a number of different substances. He also found that X-rays can penetrate considerable thicknesses of materials of low atomic number, whereas substances of high atomic number are relatively opaque. Roentgen took the first steps in identifying the nature of X-rays by using a system of slits to show that (1) they travel in straight lines, and that (2) they are uncharged, because they are not deflected by electric or magnetic fields.‍Par. 3 The discovery of X-rays aroused the interest of all physicists, and many joined in the investigation of their properties. In 1899 Haga and Wind performed a single slit diffraction experiment with X-rays which showed that (3) X-rays are a wave motion phenomenon, and, from the size of the diffraction pattern, their wavelength could be estimated to be 10-8 cm. In 1906 Barkla proved that (4) the waves are transverse by showing that they can be polarized by scattering from many materials.‍Par. 4 There is, of course, no longer anything unknown about the nature of X-rays. They are electromagnetic radiation of exactly the same nature as visible light, except that their wavelength is several orders of magnitude shorter. This conclusion follows from comparing properties 1 through 4 with the similar properties of visible light, but it was actually postulated by Thomson several years before all these properties were known. Thomson argued that X-rays are electromagnetic radiation because such radiation would be expected to be emitted from the point at which the electrons strike the wall of a cathode ray tube. At this point, the electrons suffer very violent accelerations in coming to a stop and, according to classical electromagnetic theory, all accelerated charged particles emit electromagnetic radiations. We shall see later that this explanation of the production of X-rays is at least partially correct.‍Par. 5 In common with other electromagnetic radiations, X-rays exhibit particle-like aspects as well as wave-like aspects. The reader will recall that the Compton effect, which is one of the most convincing demonstrations of the existence of quanta, was originally observed with electromagnetic radiation in the X-ray region of wavelengths.‍‎‍‎When were X-rays discovered?‍
选项：
A: Par. 1
B: Par. 2
C: Par. 3
D: Par. 4
E: Par. 5
答案: 【 Par. 2】点我阅读全文

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