多项选择题

在发电厂变电所的导体和电器选择时，若采用“短路电流实用计算法”，可以忽略的电气参数是（ ）

A.发电机的负序电抗
B.输电线路的电容
C.所有元件的电阻（不考虑短路电流的衰减时间常数）
D.短路点的电弧电阻和变压器的励磁电流
<上一题 目录 下一题>
热门 试题

未分类题
Why We LaughWe start finding things laughable — or not laughable — early in lifE.An infant first smiles at approximately eight days of agE.Many psychologists assume this is his first sign of simple pleasure— food, warmth and comfort. At six months or less, the infant laughs to express complex pleasures—such as the light of Mother's smiling facE.Between the ages of six months and one year, the baby learns to laugh for essentially the same reasons he will laugh throughout his life, says Dr. Jacob Levine, associate professor of psychology at Yale University. Dr. Levine says that people laugh to express mastery over an anxiety. Picture what happens when a father throws his child into the air. The child will probably laugh—but not the first timE.In spite of his enjoyment of 'flying', he is too anxious to laugh. How does he know Daddy will catch him? Once the child realizes he will be caught, he is free to enjoy the gamE.But more importantly, says Dr. Levine, the child laughs because he has mastered an anxiety.Adult laughter is more subtle, but we also laugh at what we used to fear. The feeling of achievement, or lack of it, remains a crucial factor. Giving a first dinner party is an anxious event for a new bridE.Will the food be good? Will the guests get along? Will she be a good hostess? Will the knives and forks, cups and saucers be all right? All goes well; the party is over. Now she laughs freely. Her pleasure from having proved her success is the foundation for her pleasure in recalling the evening activities. She couldn't enjoy the second pleasure without the first, more important one—her mastery of anxiety.Laughter is a social response triggered by cues. Scientists have not determined a brain center for laughter, and they are perplexed by patients with certain types of brain damage who go into laughing fits for no apparent reason. The rest of us require company, and a reason to laugh.When we find ourselves alone in a humorous situation, our usual response is to smilE.Isn't it hue that our highest compliment to a humorous book is to say that 'it made me laugh out of loud'? Of course, we do occasionally laugh alone; but when we do, we are, in a sense, socializing with ourselves. We laugh at a memory, or at a part of ourselves.Of course, we don't always need a joke to make us laugh. People who survive frightening situations, such as a fire or an emergency plane landing, frequently relate their story of the crisis with laughter. Part of the laughter express relief that everything is now all right. During a crisis, definitely, everyone mobilizes energy to deal with the potential problem. If the danger is avoided, we need to release that energy. Some people cry; others laugh.When we are made the target of a joke, either on a personal or impersonal level, we are emotionally involved in it. Consequently, we won't be able to laugh.Knowing that laughter blunts emotion, we can better understand why we sometimes laugh when nothing is funny. We laugh during moments of anxiety because we feel no mastery over the situation, claims Dr. LevinE.He explains, 'very often compulsive laughter is a learned responsE.If we laugh, it expresses good feelings and the fact that we are able to copE.When we're in a situation in which we can't cope, we laugh to reassure ourselves that we can!'How often have we laughed at a funeral or upon hearing bad news? We laugh to deny an unendurable reality until we are strong enough to accept it. Laughter also breaks our tension. However, we may also be laughing to express relief that the tragedy didn't happen to us. We laugh before giving a big party, before delivering a speech, or while getting a traffic ticket, to say, 'This isn't bothering mE.See? I am laughing.'But if we sometimes laugh in sorrow, more often we laugh with joy. Laughter creates aA.YB.NC.NG
A.B.
C.
D.
E.
F.
G.
H.'
I.Y
B.N
C.NG
未分类题
听力原文：M: I'm going to book a train ticket 10 days in advance because it happens to be Spring Festival.W: Don't worry. There will be extra trains added to the original schedulE.Q: What docs the woman imply?(19)A.There would be some problems for the man to secure a ticket.B.There would be no problem for the man to secure a ticket.C.There might be some extra tickets available for the man.D.The man should book the ticket even earlier.
A.W:
B.
Q:
C.There
D.
B.There
E.
C.There
F.
D.The
G.
相关试题