Currently, employing the ultra-sound inspection method to check the quality of the under-water concrete stake is perfectly correct.

Guo Jin Dynasty in the margin of Health "in the levy in mind," said Chang Ting of winter fox crossing the river a long time, to sound and water under the ice line.

This paper studies the determination of datum station with GPS and the computation problems of the sound pulse signal received by the datum station of echo pulse receiver under water.