With help of a sonicdepth-finder a proper shoal gets detected and the fishermen prepare special devices which look something like spinnings and attached to the handrails.
用超声波探测器可以定位鱼群，渔民们准备一种特别的装置：看起来象连着扶手的陀螺。
2
Based on acoustics, one can study the testing depth of sonic logging.
从波动声学的角度讨论声波测井的探测深度问题。
3
This system consists of sonic sonde, magnetic locator sub, gamma ray tool, depth system, surface preprocessing unit, data acquisition interface, PC486 and thermal plotter.