当地震设防烈度为7度及以上时,安装在室内2层及以上的电气设备应采取( )防震措施。

题型:单项选择题

问题:

当地震设防烈度为7度及以上时,安装在室内2层及以上的电气设备应采取( )防震措施。

A.变压器的安装应有防止位移、倾斜的措施

B.设备引线和设备间连线直采用软导线,并应适当放松。当采用硬母线时,应有软导线或伸缩接头过渡

C.电气设备的安装必须牢固可靠,设备安装螺栓应满足抗震要求,当采用焊接时,应验算焊缝的强度

D.设备支架在自身重力作用下的固有频率值在12Hz以上

考点:注册电气工程师供配电专业注册电气工程师(供配电专业)
题型:单项选择题

根据短文内容判断正(T)误(F)。

  We all know who Benjamin Franklin was. He was a very famous American

statesman. He was also the first man to discover electricity. Franklin liked to

study and to learn about new things. One day he heard from a friend that

something black in colour holds the heat better than something white in colour.

Franklin wanted to find out if this was true or not.

  There was snow on the ground at the time. So he put two large pieces of

cloth over the snow. One piece of cloth was black in colour, the other piece was

white. Then he waited until the sun began to shine. After several hours he looked

under the pieces of cloth and saw that the snow under the black cloth melted

much faster than the snow under the white cloth. This proved to him that the black

cloth held the heat better than the white cloth.

  Soon after this, people began to wear white hats and white clothes during

the summer because they were cooler.

( )1. Benjamin Franklin was only a scientist.

( )2. One day a friend of his told him something about the relation(关系)

between colour and heat.

( )3. Something black in colour holds heat better than something white in

colour.

(     )4. This story happened in summer.

(     )5. People wear white clothes in summer because they know it is cooler.

题型:单项选择题

信息分析成果评价包括即时评价和()。

A、最终评价

B、定性评价

C、不定性评价

D、事后评价

题型:单项选择题

决定酶催化反应类型的是

A.酶的活性中心
B.活性中心外的必需基团
C.辅酶或辅基
D.酶蛋白

题型:单项选择题

如图所示,通电金属杆ab质量m=12g,电阻R=1.5Ω,水平地放置在倾角θ=300的光滑金属导轨上.导轨宽度d=10

3
cm,导轨电阻、导轨与金属杆的接触电阻忽略不计,电源内阻r=0.5Ω.匀强磁场的方向竖直向上,磁感强度B=0.2T.若金属棒ab恰能保持静止,求电源的电动势大小E.

题型:单项选择题

根据《固定电话交换设备安装工程设计规范》程控交换机房的机房长期工作条件下的温度、湿度要求为()

A.温度:18-28湿度:40-70

B.温度:15-30湿度:35-71

C.温度:18-28湿度:40-80

D.温度:20-28湿度:40-73

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