Such a behavior corresponds to echo wave in physics.

Performance analysis of echo synchronous signal in audio watermarking;

With the development of submarine s noise reduction, there has been increasing concern with the requirement to detect underwater targets by using active sonar, hence the relative techniques about submarine s echo decreasing have become the key technology to naval armament in the world.

Changes of liquid level are usually monitored with echometers and stable decompression is achieved by controlling the reducing rate of the liquid level.

The echometer was used to monitor the change of the annular water level in the coal- bed methane(CBM)wells production,which could decrease pressure stably and continuously.

Morphological features, echolocation calls and foraging strategy in the trawling piscivorous bat: Rickett s big-footed bat Myotis ricketti;

Echolocation and Acoustic Communication in Bats;

Recent researches on Bats auditory system and echolocation in China;