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第三章测验

1、单选题：
​社会存在又称社会物质生活条件，下列不属于社会存在的选项是（）‌
选项：
A: 地理环境
B: 物质生产方式
C: 科学技术
D: 人口因素
答案: 【 科学技术】点我阅读全文

一、单选题

1、单选题：
​社区给居民提供工作机会，属于社区功能中的（）。（题目来源：全国社会工作者职业水平考试教材编写组：《社会工作综合能力全真题库卷》，知识出版社）‎
选项：
A: 社会参与功能
B: 心理支持功能
C: “生产——消费——流通”的经济功能
D: 社会控制功能
答案: 【 “生产——消费——流通”的经济功能】点我阅读全文

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

仪器分析导论单元测试

1、单选题：
‌现代仪器分析设备的特点不包括下面哪一项‌
选项：
A: 全部是化学领域的专用仪器设备。
B: 灵敏度高，检出限低。
C: 选择指向性好。
D: 操作简便,分析速度快,易于实现自动化。
答案: 【 全部是化学领域的专用仪器设备。】点我阅读全文

第一章：战略管理导论

1、单选题：
战略管理的主体是‏
选项：
A: 企业高层管理人员
B: 企业中层管理人员
C: 企业基层管理人员
D: 企业所有的管理者
答案: 【 企业高层管理人员】点我阅读全文

1.2 人体的组成、分部及解剖学的常用术语随堂测试

1、单选题：
‌属于解剖学姿势的是 ‍
选项：
A: 身体直立
B: 两眼平视
C: 手掌、足尖向前
D: 以上都是
答案: 【 以上都是】点我阅读全文

单元测试1

1、多选题：
‌创业过程重点而不确定性包括以下哪些方面：​
选项：
A:  应用的不确定性
B:  需求的不确定性
C:  模式的不确定性
D:  扩展的不确定性
答案: 【  应用的不确定性;
 需求的不确定性;
 模式的不确定性;
 扩展的不确定性】点我阅读全文

第一单元测试题

1、多选题：
​Web GIS最早由哪个机构哪一年开发？‍‍‎
选项：
A: 1960
B: 1970
C: 1980
D: 1993
E: 美国施乐公司‍
F: 美国国家航空航天局
答案: 【 1993;
美国施乐公司‍】点我阅读全文

质点运动学单元测验

1、单选题：

‍

‏选项：
A:
B:
C:
D:
答案: 【 】点我阅读全文

第1章单元测验

1、多选题：
​下面所列各种制动方式中，属于黏着制动的有​
选项：
A: 闸瓦制动
B: 磁轨制动
C: 旋转涡流制动
D: 盘形制动
E: 轨道涡流制动
答案: 【 闸瓦制动;
旋转涡流制动;
盘形制动】点我阅读全文