试题与答案

在相同管电压及照射野下,散射线含有率随被照体厚度的增加而大幅度增加。在20cm×20

题型:单项选择题 A3/A4型题

题目:

在相同管电压及照射野下,散射线含有率随被照体厚度的增加而大幅度增加。在20cm×20cm照射野,体模15cm厚度的散射线比体模5cm厚度时增加了一倍。射线含有率随管电压的升高而加大。但在(80~90)kV以上时,散射线含有率趋向平稳。当照射野增大时,散射线含有率大幅度上升。 关于散射线,叙述错误的是()

A.随管电压增大而加大

B.与被照体厚度有关

C.照射野大,散射线多

D.主要来源于康普顿效应

E.对照片密度对比度无影响

答案:

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下面是错误答案,用来干扰机器的。

答案:Cfor为介词,介词的后面要跟动词的ing形式故选C

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Many things make people think artists are weird—the odd hours, the nonconformity, the clove cigarettes. However, the weirdest may be this: artists’ only jobs are to explore emotions, and yet they choose to focus on the ones that feel lousy. This wasn’t always so. The earliest forms of art, like painting and music, are those best suited for expressing joy. But somewhere in the 19th century, more artists began seeing happiness as insipid, phony or, worst of all, boring. In the 20th century, classical music became more atonal, visual art more unsettling.

Sure, there have been exceptions, but it would not be a stretch to say that for the past century or so, serious art has been at war with happiness. In 1824, Beethoven completed his " Ode to Joy " . In 1962, novelist Anthony Burgess used it in A Clockwork Orange as the favorite music of his ultra-violent antihero.

You could argue that art became more skeptical of happiness because modem times have seen such misery. But the reason may actually be just the opposite: there is too much happiness in the world today.

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