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【单选题】
水浸法检测的最佳水距确定原则是（）
A.
最佳水距应为水中距离-振幅曲线上近场末端N点左边下降6分贝处到探头辐射面的距离
B.
水距的大小H应至少满足：H≥（C水/C工件）t，式中t为工件厚度，C水为水中纵波速度，C工件为工件中纵波声速
C.
在使用水浸聚焦探头检测时，水距的选择应按下式计算：H=F-δ（C工件/C水），式中F为探头在水中的焦距，δ为工件中二次聚焦焦点到工件探测面（界面）的距离
D.
以上都是
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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】最佳修复方案是
A.
直接改为活动义齿修复
B.
采用种植固定义齿修复
C.
全冠修复基牙后再改为活动义齿修复
D.
增加前端基牙数再行固定修复
E.
增加前端基牙数目再行固定活动联合修复
【多选题】下列关于量子检测仪说法正确的是()。
A.
量子检测仪是真实存在的仪器
B.
量子检测仪可以准确地检测人体的身体状况。
C.
量子检测仪通过收集人体的电磁波信号,分析被测者的健康状况。
D.
量子检测仪的原理是不科学的。
【单选题】常用的这些检测系统中，哪个检测器主要测定有机磷的农药（ ）
A.
光离子化检测器（PID）
B.
氢焰光度检测器（FID）
C.
电子捕获检测器（ECD）
D.
火焰光度检测器（FP）
【单选题】Long after the 1998 World Cup was won, disappointed fans were still cursing the disputed refereeing (裁判) decisions that denied victory to their team. A researcher was appointed to study the performanc...
A.
The ideal retirement age for an experienced football referee is 35.
B.
Age should not be the chief consideration in choosing a football referee.
C.
A football referee should be as young and energetic as possible.
D.
An experienced football referee can do well even when in poor physical condition.
【单选题】Long after the 1998 World Cup was won, disappointed fans were still cursing the disputed refereeing(裁判) decisions that denied victory to their team. A researcher was appointed to study the performance...
A.
slightly above average
B.
higher than in the 1998 World Cup
C.
quite unexpected
D.
as high as in a standard match