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新东方网为大家带来2020托福听力练习：聚焦节能的白光发明（下载），希望对大家有所帮助!更多内容请随时关注新东方网!
LEDs use only a quarter the energy of incandescent bulbs. But despite their efficiency, there is one thing they're not that good at: "They have a hard time giving directional light." Sangam Chatterjee, a physicist at the University of Marburg and the University of Giessen, in Germany.
Chatterjee and his colleagues may have fixed that. They devised a highly focused, but still energy-efficient light beam, by starting with something that's already a highly focused beam: a laser. The key is what they shoot the laser at: a substance with a particular structure. "I'm always tempted to say "white powdery substance" but I guess there's some connotation on that."
They synthesized the material from cages of tin and sulfur atoms decorated with hydrocarbon molecules. The laser-produced infrared light — which the human eye cannot see — goes in, but what comes out are many different optical wavelengths. "It's a molecular light converter. It basically changes the color of the light, while retaining the directionality of the lasers. So you can make something like a white laser beam containing many, many colors." That mix of colors, overall, glows bright white, like a halogen bulb in a beam. The study is in the journal Science.
This sort of low-energy focused white beam could be used for the very small — like a light source for microscopes — to the very big. "You could use this for a spotlight in the theater. And in the end it should be much more energy efficient than the typical standard spotlight." Meaning focused white light…that takes a little heat off the environment.
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LED灯使用的电量仅为白炽灯的1/4。虽然LED灯高效节能，但是它们也有不擅长的事情：“它们不能发射平行光。”桑伽姆·查特吉是德国马尔堡大学和吉森大学的物理学家。
查特吉和他的同事可能已经解决了这个问题。他们通过高度聚焦的光束——激光，发明了一种高度聚焦且节能的光束。关键就是用激光照射一种拥有特殊结构的物质。“我一直想说是白色粉状物质，不过我想关键是内部的东西。”
他们用烃分子修饰的锡和硫原子合成了这一材料。激光发出的红外线肉眼看不到，红外线进入后会产生很多不同的波长。“这是一种分子光转化器。可以改变光的颜色，但同时保留激光的方向性。这样就可以制造出含有很多种颜色的白色激光束。”混合的颜色就会发出像卤素灯泡一样的亮白色光束。这一研究结果发表在《科学》杂志上。
这种低能聚焦白色光束既可以应用于显微镜光源这种小物件上，也可以应用到大场合。“这种光束可以用作剧院的聚光灯。比普通的标准聚光灯更加节能。”这表明聚焦白光可以消耗环境中的一部分热量。
谢谢大家收听科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。
重点讲解：
1. be good at 擅长的;精通的;能干的;
例句：He is good at mental arithmetic.
他擅长心算。
2. start with (以做某事) 开始;
例句：I wanna start with a song that means a lot to me.
我打算由一首对我意义非凡的歌开始。
3. be tempted to do sth. 想做…的;希望做的;
例句：I was sorely tempted to complain, but I didn't.
我极想发牢骚，但还是没开口。
4. in the end 最终;
例句：He debated buying a new car, but didn't in the end.
他思量很久是否买辆新汽车，但最后还是没买。
以上是新东方网为大家带来的2020托福听力练习：聚焦节能的白光发明（下载），希望认真积极的备考，早日取得优异的成绩。更多内容请随时关注新东方网!
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