SSS 2012-08-22(在线收听) |
This is scientific American sixty seconds science. I'm Christopher Intagliata. Got a minute? Camouflage face paint can make a soldier invisible to enemy in eyes. But it won't shield him from the shearing heat of a roadside bomb, a lethal eleven hundred degrees Fahrenheit. And the greases and oils in the makeup just add fuel to the fire, essentially cooking the soldier's face. But researchers have come up with a safer, heat-blocking alternative, presented in this week at a meeting of the American Chemical Society.
Conventional camo paint has tiny nano particles of pigment, they are great at reflecting visible light which is why the paint looks green or black or tan. But the particles don't reflect longer wavelengths like heat. To do that, you need larger globs of pigment. So researchers bundled together a bunch of those smaller particles into chunks the size of grains of sand, large enough for heat rays to bounce right off. And it swapped out the grease for silicone which adds smoothest and spreadability to cosmetics, but won't catch fire. Under a blowtorch, the new camo paint can block out heat for fifteen seconds, long enough to weather a bomb blast and keep soldiers cool in the heat battle. |
原文地址:http://www.tingroom.com/lesson/sasss/2012/8/199323.html |