针对声波测井薄层探测的需要，用半解析方法求解了地层为水平多层介质时柱状井孔内脉冲点源激发的声场。

The acoustic wave field excited by a pulsed point source in a fluid-felled borehole surrounded by horizontal multiple-layered media is solved by the send-analytical method.

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然后介绍了基于超声波测距的孔内空区形态探测系统的设计。

Then, the design of the detection system in borehole of the mined-out area based on ultrasonic distance measurement was introduced.

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然后，用专用钻头在保险杠上开孔，并将探测器别离装入孔内。

Then, using special drill hole in the bumper, and detectors were put into holes.

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