一回路压力边界是如何定义的?

题型:问答题 简答题

问题:

一回路压力边界是如何定义的?

考点:动力与电气工程核电核电题库
题型:问答题 简答题

一个电子(质量为m、电荷量为-e)和一个正电子(质量为 m、电荷量为e)以相等的初动能Ek相向运动,并撞到一起,发生“湮灭”,产生两个频率相同的光子,设产生光子的频率为v。若这两个光子的能量都为hv,动量分别为p和p',下面关系中正确的是 [ ]

A.hv=mc2,p=p'

B.,p=p'

C.hv=mc2+Ek ,p= -p'

D.,p=-p'

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如图所示的LC振荡电路,在某时刻的磁场方向如图所示,则下列判断不正确的是(   )

A.若磁场正在增强,则电场能正在减少,电容器上极板带正电

B.若磁场正在减弱,则电场能正在增强,电容器上极板带正电

C.振荡电流的变化周期为:

D.电场能量的变化周期为:π

题型:问答题 简答题

Maybe you are an average(一般的) student. You probably think you will never be a top student. However, anyone can become better if he or she does his or her best. Here are some tips to help you.

★ Plan your time carefully. You should plan your time for things such as eating, sleeping and dressing. Then make a good, regular time for studying. But don’t forget to set enough time for entertainment.

★ Keep your study quiet and clean. The study should have a desk, a chair and some study materials, but no games, no radio and no television! When you sit down to study, you can put your heart into it. Make good use of your time.

★ Listen to everything that the teacher says. Listening carefully in class means less work later. Taking notes will help you remember what the teacher says.

★ After you get home from school, go over your notes. Review the important points. If you know what your teacher is going to discuss next day, read the material. It will help you study better.

★ Develop a good attitude to tests. The purpose of a test is to show what you have learned about a subject. It helps you know what you are not good at. The world will still go on even if you fail in a test, so don’t be too worried.

小题1:How many tips are mentioned in the passage?

A.Three.

B.Four.

C.Five.

D.Six.小题2:What does the underlined word “study” mean in Chinese?

A.学习

B.研究

C.书房

D.教室小题3:Which is a good place for studying?

A.A clean and beautiful place.

B.The place with a computer.

C.The place with a television and a radio.

D.A quiet place with a chair, a desk and some study materials.小题4:Which of the following is NOT true?

A.The purpose of a test is to show what you are good at.

B.After class, you should review what you have learned.

C.You should listen to your teacher and take notes carefully in class.

D.When you plan your time, you should think of the time for eating, sleeping and so on.小题5:What’s the passage mainly about?

A.How to become a better student.

B.How to plan your time.

C.How to study English.

D.How to take notes.

题型:问答题 简答题

m阶B树的根结点至少有几棵子树

A.0

B.2

C.m-1

D.1

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随着web2.0时代的到来,数据将从非结构化到半结构化到结构化。

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