日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区

您現(xiàn)在的位置: Language Tips> Easy English> Odd Question  
   
 





 
咳嗽也能拍到膠卷上?
[ 2008-11-24 18:19 ]

如果你看過《友好的巨人》,你一定記得巨人會在大家都睡著的時候出現(xiàn)在街道上,手上拿著長長的吹管,他會為小孩子吹入美夢,為做惡夢的小孩把惡夢吹出來,夢都裝在玻璃瓶中,放在巨人背著的包包里。既然無形的夢可以裝進包里,咳嗽為什么不能拍到膠卷上呢?

咳嗽也能拍到膠卷上?

At Pennsylvania State University, a professor of engineering has captured something less whimsical but no less ephemeral — a cough — on film.

The image, published online Oct. 9 by The New England Journal of Medicine, was created by schlieren photography, which “takes an invisible phenomenon and turns it into a visible picture,” said the engineering professor, Gary Settles, who is the director of the university’s gas dynamics laboratory.

“In my lab we use this technique a lot,” Dr. Settles said. “Often it’s used for other things, like in supersonic wind tunnels, to show shock waves around high-speed aircraft.”

The process involves a small, bright light source, precisely placed lenses, a curved mirror, a razor blade that blocks part of the light beam and other tools that make it possible to see and photograph disturbances in the air.

A healthy student provided the cough. The expelled air, traveling at 18 miles per hour, mixed with cooler surrounding air and produced “temperature differences that bend light rays by different amounts,” Dr. Settles said.

He went on: “The next thing is, you get a couple of people in front of the mirror talking, or one coughs on another, and you see how the air flow moves, how people infect one another. Or you look at how coughing can spread airborne infection in a hospital. This is really a suggestion for how we might study all that. The techniques used in wind tunnels can be used to study human diseases.”

The final photograph, in a full-scale mock-up of an aircraft cabin, captures in microseconds the flash of an explosion under a mannequin in an airplane seat and the propagation of shock waves into the cabin. The blast was a re-creation of a terrorist’s attempt in 1994 to bring down a Philippine Airlines flight with a nitroglycerin bomb. The plane did not crash, but the explosion did kill the passenger seated over the bomb. The simulation used a less intense explosion than the actual bombing.

“The simulation helps to understand how the energy of an onboard blast reverberates around the cabin,” Dr. Settles said, “and it is also useful to check the results of computer blast simulations.”

This shadowgram captures an instant during the firing of a Smith&Wesson 44 Magnum revolver. Blast waves and propellant gases are observed to originate first from the cylinder and later from the muzzle of the gun. Propellant gas envelopes the hand of the shooter, leaving gunpowder residue. The bullet itself travels at transonic speed, i.e. close to the speed of sound. This is a colorized version of a monochrome original image.

(來源:《紐約時報》網(wǎng)站 實習生許雅寧)

我要了解更多趣味百科知識

 
英語點津版權說明:凡注明來源為“英語點津:XXX(署名)”的原創(chuàng)作品,除與中國日報網(wǎng)簽署英語點津內(nèi)容授權協(xié)議的網(wǎng)站外,其他任何網(wǎng)站或單位未經(jīng)允許不得非法盜鏈、轉載和使用,違者必究。如需使用,請與010-84883631聯(lián)系;凡本網(wǎng)注明“來源:XXX(非英語點津)”的作品,均轉載自其它媒體,目的在于傳播更多信息,其他媒體如需轉載,請與稿件來源方聯(lián)系,如產(chǎn)生任何問題與本網(wǎng)無關;本網(wǎng)所發(fā)布的歌曲、電影片段,版權歸原作者所有,僅供學習與研究,如果侵權,請?zhí)峁┌鏅嘧C明,以便盡快刪除。
相關文章 Related Story
 
 
 
本頻道最新推薦
 
Walking in the US first lady's shoes
“準確無誤”如何表達
英國新晉超女蘇珊大媽改頭換面
豬流感 swine flu
你有l(wèi)ottery mentality嗎
翻吧推薦
 
論壇熱貼
 
別亂扔垃圾。怎么譯這個亂字呀?
橘子,橙子用英文怎么區(qū)分?
看Gossip Girl學英語
端午節(jié)怎么翻譯?
母親,您在天堂還好嗎?

 

<strong id="xdwva"><div id="xdwva"></div></strong>
<label id="xdwva"></label>

<thead id="xdwva"></thead>
    <label id="xdwva"></label>

  1. 日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区 久久九九久精品国产日韩经典 国产国语国拍精品 啊v在线观看高清无码 视频一区二区欧美 久久精品爱爱唉爱