超声波具有指向性好，在水中衰减小，束射特性优良。

Ultrasonic has a good pointing, the attenuation in water is small, beam radio feature fine.

youdao

超声波具有指向性好，在水中衰减小，束射特性优良。

Ultrasonic has a good pointing, the attenuation in water is small, beam radio feature fine.

youdao