{HEAD ~ A larger area} of {TAIL ~ the transmission surface} causes the ultrasonic wave to have a larger sound pressure 
{ HEAD ~ A larger area } of { TAIL ~ the transmission surface } causes the ultrasonic wave to have a larger sound pressure
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH