超声波发射
/ˈʌlnɑː ˈnɜːv/
n
English: ultrasound waves emission · 超声波发射
English · ultrasound waves emissionEspañol · emisión de ondas ultrasónicasFrançais · émission d’ultrasons
释义：Production of very high-frequency sound vibrations whose echo is captured and analyzed.