英语 英语 日语 日语 韩语 韩语 法语 法语 德语 德语 西班牙语 西班牙语 意大利语 意大利语 阿拉伯语 阿拉伯语 葡萄牙语 葡萄牙语 越南语 越南语 俄语 俄语 芬兰语 芬兰语 泰语 泰语 泰语 丹麦语 泰语 对外汉语

SSS 2011-08-12

时间:2011-09-05 05:48来源:互联网 提供网友:gmeng   字体: [ ]
特别声明:本栏目内容均从网络收集或者网友提供,供仅参考试用,我们无法保证内容完整和正确。如果资料损害了您的权益,请与站长联系,我们将及时删除并致以歉意。
    (单词翻译:双击或拖选)

 This is Scientific American’s 60-Second Science. I’m Sophie Bushwick. Got a Minute?

 
What's the best way to find out if an unknown mixture contains a specific substance, like an environmental contaminant? You could use an expensive, bulky gas chromatograph—but Harvard researchers have developed an instrument you can carry in your pocket. They describe the device, called an inverse1 opal, in the Journal of the American Chemical Society. 
 
An inverse opal is a chip of layered glass that includes numerous tiny channels. This mini-labyrinth gets treated with chemicals to modify its inner surfaces. The resulting porous2 chip then sucks up only liquids that have specific surface tensions. When such a liquid enters the network, it changes the chip's color over a set area. An inverse opal designed to determine if ethanol is laced with methanol could thus reveal the letter M if the poison is present.
 
With this so-called Watermark Ink writing, the chips could also serve as secret code devices. For example, swabbing a chip with water might make a decoy word like “hello” visible. While exposure to, say, benzene, could expose a secret message, such as “ditch your gas chromatograph.
 
Thanks for the minute. For Scientific American’s 60-Second Science. I’m Sophie Bushwick.

点击收听单词发音收听单词发音  

1 inverse GR6zs     
adj.相反的,倒转的,反转的;n.相反之物;v.倒转
参考例句:
  • Evil is the inverse of good.恶是善的反面。
  • When the direct approach failed he tried the inverse.当直接方法失败时,他尝试相反的做法。
2 porous 91szq     
adj.可渗透的,多孔的
参考例句:
  • He added sand to the soil to make it more porous.他往土里掺沙子以提高渗水性能。
  • The shell has to be slightly porous to enable oxygen to pass in.外壳不得不有些细小的孔以便能使氧气通过。
本文本内容来源于互联网抓取和网友提交,仅供参考,部分栏目没有内容,如果您有更合适的内容,欢迎点击提交分享给大家。
------分隔线----------------------------
TAG标签:   sss  托福素材
顶一下
(1)
100%
踩一下
(0)
0%
最新评论 查看所有评论
发表评论 查看所有评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:
听力搜索
推荐频道
论坛新贴