题目内容

冲击回波声频法（IAE）相对传统冲击回波法的优点有哪些？

A. 采用拾音器（麦克风）进行信号接收
B. 采用空气耦合，空气中不存在剪切力，因此无法传播横波（S），以及会对面波（R）有很大削弱
C. 加速度传感器有明显的固有峰值，而拾音器的频谱上一般没有明显的共振峰值。
D. 不受钢筋影响，测试精度高

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冲击回波声频法（IAE）对隧道衬砌进行检测时存在哪些缺点？

A. 对脱空及缺陷的检测分辨率低
B. 测试效率较低
C. 同时受防水板的影响
D. 难以测试初支及背后岩体状况

冲击回波声频检测技术（IAE）采用拾声器拾取被测体的振动信号，并传送到信号处理仪器；将所记录的信号进行分析，从而确定结构的厚度和缺陷的位置。

A. 对
B. 错

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Para. 6M: Today’s teenagers do not seem to be as worried about marketing companies targeting them through ads on social media as they are about ___________ _ from their parents.S1: Members of Generation Z such as Valerie do not like their parents wanting to see online.S2: Valerie limits what her parents can see about what she does on_____.