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  • Thanks to graphene, ultra-high pitched sonar is now possible. Graphene you are like the

  • Superman of materials. OrWould sonar make it more like Batman? I don’t know stuff

  • about comics.

  • Hi science lovers, Julian here for DNews. I’m sure the majority of you know what sonar

  • is but just in case, I’ll explain. Sonar stands for SOund Navigation And Ranging, and

  • it involves sending out a sound wave and bouncing it off an object. Timing how long it takes

  • to come back will tell you how far away the object is, which is the same principle as

  • radar. Humans use it mostly under water because the mechanical sound waves travel well through

  • it, while the electromagnetic waves from radar get attenuated by the water much more quickly.

  • People with satellite TV who lose signal on really stormy days know what I’m talking

  • about.

  • Sonar is said to have been invented in 1490 when Leonardo Da Vinci stuck a tube in water

  • and listened to ships pass but really, a tube? Does that count as an invention? That’s

  • just sloppy, Leo.

  • Anyway, sonar has been around long before Da Vinci came along and invented everything.

  • Famously dolphins and bats use high frequency sounds to echo-locate and communicate. Were

  • talking really high frequency too. A human can hear sounds from 20 Hz to 20,000 Hz, and

  • that’s if they have amazing hearing and are young and never go to concerts. We hear

  • best where human speech speech lives, in the 1000 to 5000 Hz range, or 1-5 kHz. Some species

  • of bats can hear as low as 1 kHz too, but a bat’s hearing may be as high pitched as

  • 200 kilohertz. Literally 10 times higher than humans.

  • It’s not easy for our equipment to detect or emit sounds that high. Dynamic microphones

  • work when sound waves vibrate a diaphragm, which in turn causes a magnet to move around

  • a wire and generate an electrical current, and speakers work the same way but in reverse.

  • The diaphragms in these mics and speakers are usually paper or plastic, which aren’t

  • sensitive enough for detecting ultra-high frequencies.

  • Now, thanks to the wondiferous material of graphene, a huge range of frequencies can

  • be detected and reproduced. It’s because graphene is so thin. It’s just, say it with

  • me now, one atom thick. Scientists at UC Berkeley realized this would make it an ideal diaphragm,

  • and have created microphones and speakers that work well below 20 Hz and all the way

  • up to 500 kHz. Yeah, you thought you were bad, bats. Now what?

  • Actually studying bats was one of the first tests for these new microphones. The researchers

  • took them to a nearby park to test them out and found the mics pick up the bats chirps

  • well across the spectrum. Plus theyre so small they can actually be mounted on the

  • bats themselves.

  • Aside from studying bats, the mics and speakers could have loads of other uses. The speakers

  • can emit sharp pulses at high frequencies, meaning they can be used for measuring distance

  • much more accurately than traditional methods. The researchers envision a world where ultrasound

  • is part of your cell-phone’s arsenal for communication. I’m thinking that’s not

  • creative enough though. What about a personal sonar device for the blind? Or since these

  • graphene speakers are 99% efficient at turning electricity into sound, compared to the 8%

  • efficiency of your headphones, why not have some killer and lightweight portable stereos?

  • The researchers even claim the sound waves can penetrate objects like steel, something

  • radio waves can’t do. If you can convert those sound waves into an image… X-Ray vision,

  • anyone? Let’s innovate, guys!

  • One company that’s innovating all over the place is Intel. With processors, wearables,

  • datacenters, devices on the internet of things, and of course, in your Mac or PC, Intel is

  • driving innovation. If there’s Intel inside, youre going to have a better experience

  • outside. Theyre creating breakthrough technologies that make amazing experiences possible, and

  • they like us, so they make DNews possible too.

  • Bat sonar is pretty incredible but nature is an arms race, and some moths have evolved

  • a way to go stealth mode. Check out the amazing story here.

  • How would you used these graphene mics and speakers? Do you have some ingenious use I

  • didn’t come up with? Let us know in the comments, or facebook, or twitter @DNews.

  • Subscribe for more, and I’ll see you next time on DNews.

Thanks to graphene, ultra-high pitched sonar is now possible. Graphene you are like the


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如果人類有聲納會怎樣? (What If Humans Had Sonar?)

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    alisa 發佈於 2021 年 01 月 14 日