从放大器输出端测试至末端的驻波比,前端未接任何放大器或有源器件,其驻波比要求小于()

题型:填空题

问题:

从放大器输出端测试至末端的驻波比,前端未接任何放大器或有源器件,其驻波比要求小于().

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题型:填空题

According to a report, cigarette smoking ______ in all indoor public places in our city next year.

.

A.will ban

B.have banned

C.will be banned

D.have been banned

题型:填空题

(16分)图1是交流发电机模型示意图。在磁感应强度为B的匀强磁场中,有一矩形线圈abcd可绕线圈平面内垂直于磁感线的轴转动,由线圈引起的导线ae和df分别与两个跟线圈一起绕转动的金属圈环相连接,金属圆环又分别与两个固定的电刷保持滑动接触,这样矩形线圈在转动中就可以保持和外电路电阻R形成闭合电路。图2是线圈的主视图,导线ab和cd分别用它们的横截面来表示。已知ab长度为L1,bc长度为L2,线圈以恒定角速度ω逆时针转动。(只考虑单匝线圈)

(1)线圈平面处于中性面位置时开始计时,试推导t时刻整个线圈中的感应电动势e1的表达式;

(2)线圈平面处于与中性面成φ0夹角位置时开始计时,如图3所示,试写出t时刻整个线圈中的感应电动势e2的表达式;

(3)若线圈电阻为r,求线圈每转动一周电阻R上产生的焦耳热。(其它电阻均不计)

题型:填空题

One period of our lives when better results are demanded of us is, strangely enough, childhood. Despite being young we are expected to achieve good grades, stay out of trouble, make friends at school, do well on tests, perform chores at home and so on. It’s not easy.

The good news is that being likeable can help a child perform better. Likeable children enjoy many advantages, including the ability to cope(对付) more easily with stresses of growing up.

In her book Understanding Child Stress, Dr. Carolyn Leonard states that children who are likeable and optimistic are able to gain support from others. This leads to focus and resilience, the ability to recover from or adjust early to life stress; a child who has adequate emotional armor can continue down the path to success. Much research shows that resilience has enabled children to succeed in school, avoid drug abuse, and develop a healthy self-awareness.

Why does a likeable child more easily handle stress and do better in his or her life? Because likeability helps create what’s known as a positive feedback loop(回馈圈). The positive feelings you want to see in other people are returned to you, creating constant encouragement and motivation to deal with the daily stress of life.

This feedback loop continues into adulthood. To return once again to the example of teaching, learning becomes easier with a likeable personality. Michael Delucchi of the University of Hawaii reviewed dozens of studies to determine if likeable teachers received good ratings because of their likeability or because they in fact taught well. Delucchi found that “Students who perceive(察觉) a teacher as likeable, in contrast to(比照) those who do not, may be more attentive to the information that the teacher delivers and they’ll work harder on assignments, and they will learn more.”

You may have noticed this pattern in your own life when you try to give some advice. The more positive your relationship with that person, the more he or she seems to listen, and the more you feel certain that that person has heard you and intends to act on your words.

小题1:The writer implies in the first paragraph that __________.

A.children are expected much than we usually think

B.life is not easy for every one of us

C.better education results in smarter children

D.to be a likable child is almost impossible小题2:According to Dr. Leonard, likeable children __________.

A.can cope more easily with stress independently

B.know how to avoid trouble and unpleasant events

C.are always optimistic and ready to help those in need

D.can achieve more and understand themselves better小题3:The term “emotional armor” in paragraph 3 means __________.

A.mental support from friends

B.mental support from adults

C.failures in life

D.ability to handle life stress小题4:The main purpose of the studies done by Michael Delucchi is to find __________.

A.if a likeable teacher has a positive personality

B.if a likeable teacher draws more attention

C.how a teacher’s likeability gains popularity

D.how a likeable teacher’s teaching style is formed小题5:The passage aims at proving that __________.

A.likeable people do better in life generally

B.likeable people do better in their childhood

C.social creatures enjoy more advantages

D.likeable people give better advice

题型:填空题

由于血脑屏障破坏所致的肿瘤增强是()

A.脑膜瘤

B.垂体瘤

C.听神经瘤

D.胶质瘤

E.三叉神经瘤

题型:填空题

在各种事故因果类型中,事故的发生多为()型。

A.连锁

B.多因致果

C.集中

D.复合

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