某110kV变电站接地网范围为1209000174150m,由15900017415

题型:单项选择题 案例分析题

问题:

某110kV变电站接地网范围为1209000174150m,由15900017415m正方形网络组成,接地体为60×8mm2截面的镀锌扁铁,埋深0.8m。已知土壤电阻率为p=300Ω·m,请回答下列问题。(供配电2008)

若接地装置的接地电阻为1Ω,110kV有效接地系统计算入地短路电流为10kA,接地短路电流持续时间为0.5s,最大跨步电位差系数Kmax=0.126,计算最大跨步电位差数值并判断下列哪项是正确的()?

A.8740V,不满足要求

B.1260V,满足要求

C.1260V,不满足要求

D.543.1V,满足要求

考点:电气工程师(发输变电)接地接地题库
题型:单项选择题 案例分析题

My friend’s grandfather came to America from Eastern Europe. After being processed (移民入境检查) at Ellis Island, he went into a cafeteria (自助餐厅) in Lower Manhattan to get something to eat. He sat down at a table and waited for someone to take his order. But nobody came to him. Later a woman with a plate full of food sat down opposite him and told him how a cafeteria worked.

“Start out at the end,” she said. “Just go along the line and pick out what you want. At the other end he’ll tell you how much you have to pay.”

“I soon learned that’s how everything works in America,” the grandfather told my friend. “Life is like a cafeteria here. You can get anything you want only if you are willing to pay the money. You can even get success, but you’ll never get it if you wait for someone to bring it to you. You have to get up and get it yourself.”

小题1:Where do you think the old man came from?

A.Poland.

B.Australia.

C.Canada.

D.Japan小题2:From the passage, we know if you want to get success in America, you should ___________.

A.get help form your friends

B.try to get it by yourself

C.know how a cafeteria works

D.get up again if you fail小题3:Which of the following is TRUE?

A.The old man sat down opposite the woman so that she could take his order.

B.The old woman sat down opposite the old man so that she could serve him.

C.Although the woman didn’t know the old man, she told him how to get something to eat in the cafeteria.

D.Although the woman didn’t know the old man, she decided to pay the bill for him.小题4:What does the word “it” in the third paragraph (段落) refer to?

A.The food served in the cafeteria.

B.The success one wants to get.

C.The bill one has to pay in the cafeteria.

D.The plate used in the cafeteria.小题5:Which is the best title for the passage?

A.From Eastern Europe to America

B.Eating in an American Cafeteria

C.How to Eat in a Cafeteria

D.Life Is Like a Cafeteria in America

题型:单项选择题 案例分析题

国泰航空公司发现许多旅客不愿意去香港,原因是入境手续烦琐。为此公司主管积极与香港政府商议,经过长时间的讨论,双方签定了协议。公司每年向香港政府提供一笔资金,雇佣更多的入境检查官员,但这些官员主要为该公司办理入境手续。这样使得旅客等待时间减少,从而提高该公司的竞争力。这是环境中的()。

A、人口环境

B、经济环境

C、科技环境

D、社会文化环境

D、政治法律环境

E、自然环境

题型:单项选择题 案例分析题

根据相关系数r的特点,下列对r取值的意义表述正确的是( )。

A.r值若趋近+1,表示X、Y变量之间线性相关程度密切,趋近-1表示不密切

B.r=0表示两个变量之间不存在任何相关关系

C.在大多数情况下,0<|r|<1表示X、Y变量之间存在一定的线性关系

D.|r|永远不会等于1

题型:单项选择题 案例分析题

转帐业务按转帐收、付款单位开户行不同,一般可分为()种类型

A、2种

B、3种

C、4种

D、5种

题型:单项选择题 案例分析题

加强和改进党的建设,要坚持和健全民主集中制,增强党的()和团结统一。

A.生机

B.活力

C.创造力、战斗力

D.凝聚力

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