Using sonar to navigate: Bats do it, dolphins do it, and now humans can do it, too: Graphene-based microphone, speaker yield lightweight ultrasonic receiver, transmitter — ScienceDaily

Source from: JL Admin | 2015-08-25
Speakers and microphones both use diaphragms, typically made of paper or plastic, that vibrate to produce or detect sound, respectively.…
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Credit: © www.sciencedaily.com/releases/2015/07/150707134625.htm