SSS 2011-08-12
时间：2019-01-08 作者：英语课 分类：Scientific American(八)月
英语课
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 inverse 1 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 porous 2 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.
adj.相反的，倒转的，反转的；n.相反之物；v.倒转
- 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。