| 查看: 359 | 回复: 4 | ||
| 【奖励】 本帖被评价4次，作者ltl3s322增加金币 3 个 | ||
| 当前主题已经存档。 | ||
[资源]
[科学美国人-60秒科学]（09-04-22）一分钟新闻【已搜索无重复】
|
||
一分钟的科技新闻PDF+mp3，语速中上，有兴趣的可以下一下。五一发一小贴，估计都在放假 http://g.zhubajie.com/urllink.php?id=50177665ve27ync5qzok17i http://g.zhubajie.com/urllink.php?id=50177665ve27ync5qzok17i 下面是全文预览 April 22, 2009 Ear Cells Actively Amplify Sound A study in the journal Public Library of Science ONE reveals that the ear's hair cells act like tiny motors and respond to sound by swaying and driving electrical currents that cause positive feedbacks, which amplify sound. Karen Hopkin reports. Just when you thought you’d heard everything, scientists have found that the reason you can hear everything—including things that are very quiet—is because your ears have tiny tubelike motors that mechanically amplify sounds. You’ve probably heard that it’s the hair cells in your ears that allow you to hear. These cells sport tufts of spiky hairs that are like little molecular mohawks. When sound waves enter the ear these hairs vibrate, and that motion then gets translated into an electrical message that tells your brain that there’s something worth listening to. But the movement of those hairs is not passive, like tall grass swaying in the breeze. The electrical signals they produce feed back on the system, causing the hairs to tilt even more. It’s that so-called “flexo-electric effect” that basically boosts the audio signal and amplifies the sound, findings published in the April 22nd issue of the journal Public Library of Science ONE. The scientists behind the study also note that the length of the hairs in different species explains why animals like bats can detect such high frequency sounds. It doesn’t, however, explain why your kids can hear their cell phone vibrate two rooms away, yet they never seem to hear a word you say. —Karen Hopkin [ Last edited by ltl3s322 on 2009-5-1 at 20:38 ] |
回复此楼» 猜你喜欢
2026年机械制造与材料应用国际会议 （ICMMMA 2026）
已经有4人回复
-
磺酰氟产物，毕不了业了！
已经有6人回复
-
求助:我三月中下旬出站，青基依托单位怎么办？
已经有9人回复
-
Cas 72-43-5需要30g，定制合成，能接单的留言
已经有8人回复
-
北京211副教授，35岁，想重新出发，去国外做博后，怎么样？
已经有8人回复
-
论文终于录用啦！满足毕业条件了
已经有25人回复
-
自荐读博
已经有3人回复
-
不自信的我
已经有5人回复
-
投稿Elsevier的杂志（返修），总是在选择OA和subscription界面被踢皮球
已经有8人回复
太快了，基本跟不上。 
5楼2009-05-13 18:07:13
简单回复
2009-05-02 11:32
回复
fanxs883楼
2009-05-03 15:44
回复
ttzzhang4楼
2009-05-11 20:20
回复
