The resulting ultrasonic sound wave can then be directed out in a tightly controlled beam.
The resulting ultrasonic sound wave can then be directed out in a tightly controlled beam.
由此超声音波可以用严格控制声音的方向。
The resulting ultrasonic sound wave can then be directed out in a tightly controlled beam.
由此超声音波可以用严格控制声音的方向。