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试述光纤中的全反射传光过程

答案

参考答案：

光线以θ角入射到光纤的入射端面上，经折射以θ1角进入光纤後到达芯体与涂层间的光滑界面上，当入射光线满足全反射条件时，便会在界面上发生光纤内的全反射，全反射光线又以同样的角度在相对界面上发生第二次、第三次...若干次全反射，也就是光线在光纤内形成导波，直到从光纤的另一端面（即出射端面）射出，完成传光过程

填空题


In the following passage, there are 25 blanks representing words that are missing from the context. You are to put back in each of the blanks with the missing word. Write your answers on the ANSWER SHEET. The time for this section is 25 minutes.
Compared with the immediate practical responsibility of the scientist, the (1) of the artist must seem puny. The decision which faces (2) is not one of practical action: of course he will try to throw this (3) into the scale, and that weight, if he is a writer or (4) a painter of genius, may have its effect. For the novelist—in our society the only artist who has a mass audience and at the same time effective economic control of the means of addressing (5) —the hope of some decisive influence is a reasonable (6) . For him, since he takes of all artists (7) is probably the largest portion of his culture as material, there is no (8) escape from the necessity for treating the content of his work seriously than (9) is for the social psychologist he is coming so closely to resemble. The dichotomy which people have tried to establish between artistic proficiency and (10) content is becoming unbearable to almost all sensitive minds. I doubt if it has ever been real— we might have admired Shelley as (11) if he had been indifferent to such things as war and tyranny, though I doubt it; certainly (12) he been indifferent we should never have been led by (13) .
There is no Hippocratic oath in literature, and I am not attempting to draw (14) up. As far as I am concerned, the artist is a human being writ large and his (15) are the ethics of any human being. Perhaps I can best illustrate (16) seems to me the new (17) of those duties of assertion and refusal from one writer, and I do not (18) it is without significance that this (19) projects the whole situation of choice into a scientific parable, the (20) of a pestilence: a (21) many human (22) are called to fight against, called not by any supernatural (23) but by the simple fact that the fight against a plague is (24) like a biological human (25) .
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判断题

警察的社会管理职能具有鲜明的政治性和强烈的阶级性。( )
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