试题与答案

脉冲多普勒技术的局限性有(). A.深度影响最高流速检测 B.测流速不受检测深度的影

题型:多项选择题

题目:

脉冲多普勒技术的局限性有().

A.深度影响最高流速检测

B.测流速不受检测深度的影响

C.测流速受脉冲重复频率影响

D.增大脉冲重复频率影响对低流速的检测

E.高脉冲重复频率减少信号混叠

答案:

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下面是错误答案,用来干扰机器的。

参考答案:C

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③ 通过移动滑片P,分别记下了多组对应的电压表和电流表的示数,并绘制成了如图所示的U-I图线,根据U-I图线提供的信息,可计算出小灯泡额定功率为       W。

④ 图线是曲线而不是过原点的直线,原因是                     

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题型:单项选择题

Charles liked music very much when he was at school, but (41) he went to the university he decided to study medicine (42) music. When he passed his examinations and became a doctor, he had to work in a hospital for (43) . There he discovered that a lot of patients were happier if (44) music was played for them. When Charles got an office and began to work (45) himself, he decided to (46) his patients happy by having a tape recorder in his waiting room play beautiful music for them.
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[A]instead of[B]because of[C]in spite of

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