LED Lighting

　　1　An accidental discovery announced recently has taken LED lighting to a new level, suggesting it could soon offer a cheaper, longer-lasting alternative to the traditional light bulb. The breakthrough adds to a growing trend that is likely to eventually make Thomas Edison's bright invention1 obsolete.LEDs are already used in traffic lights, flashlights, and architectural lighting. They are flexible and operate less expensively than traditional lighting.

　　2　Michael Bowers, a graduate student2 at Vanderbilt University, was just trying to make really small quantum dots, which are crystals generally only a few nanometers big. Quantum dots contain anywhere from 100 to 1,000 electrons3. They're easily excited bundles of energy, and the smaller they are, the more excited they get. Each dot in Bowers' particular batch was exceptionally small, containing only 33 or 34 pairs of atoms.

　　3　When you shine a light on quantum dots or apply electricity to them, they react by producing their own light, normally a bright, vibrant color. But when Bowers shined a laser on his batch of dots, something unexpected happened. He was surprised when a white glow covered the table. The quantum dots were supposed to emit blue light4, but instead they were giving off a beautiful white glow.

　　4　Then Bowers and another student got the idea to stir the dots into polyurethane and coat a blue LED light bulb with the mix. The lumpy bulb wasn't pretty, but it produced white light singular to a regular light bulb.

　　5　LEDs produce twice as much light as a regular 60 watt bulb and bum for over 50,000 hours. The Department of Energy estimates LED lighting could reduce U. S. energy consumption for lighting by 29 percent by 2025. LEDs don't emit heat, so they're also more energy efficient. And they're much harder to break.

　　6　Quantum dot mixtures could be painted on just about anything5 and electrically excited to produce a rainbow of colors, including white. The main light source of the future will almost surely not be a bulb. It might be a table, a wall, or even a fork.

　　词汇：

　　LED / ,eli:’di: / = light-emitting diode发光二极管　　obsolete adj.过时的，被淘汰的

　　flashlight n.手电筒　　architectural adj.建筑的　　quantum n.量子

　　crystal n.晶体　　batch n.一批　　vibrant adj.(颜色)鲜明的

　　polyurethane n.聚亚安酯　　lumpy adj.粗糙的

　　注释：

　　1.bright invention：聪明的发明

　　2.graduate student：研究生

　　3.Quantum dots contain anywhere from 100 to 1,000 electrons：量子点含100～1000个电子不等。anywhere是“(限定范围内的)任何一点”。又如：

　　His monthly salary is anywhere between 3,000 yuan to 5,000 yuan.他的月工资在3000～5000元之间。

　　4.The quantum dots were supposed to emit blue light：按常规，量子点会发出蓝色光。be supposed to是“被期望(按规则、惯例)做某事”。又如：

　　They were supposed to have finished writing the report three days ago.他们三天前就该写完那份报告。

　　5.just about anything：几乎任何东西。about = almost。

　　练习

　　1.Paragraph l ________

　　2.Paragraph 3 ________

　　3.Paragraph 5 ________

　　4.Paragraph 6 ________

　　A　LED Lighting Is Not Mature

　　B　LED Lighting Will Replace Traditional Lighting

　　C　Almost Everything Could Be the Main Light Source in the Future

　　D　LED Lighting Has Many Advantages

　　E　Bowers Made an Unexpected Discovery

　　F　LED Light Bulbs Look Lumpy

　　5.Unlike traditional lighting, LEDs do not give out heat so ________.

　　6.Edison's bright invention is likely to be outdated because ________.

　　7.Something unexpected happened during Bower's experiment when ________.

　　8.Over one quarter of energy consumption for lighting could be saved by 2025 if ________.

　　A　traditional lighting is less durable and dearer

　　B　a laser excited the quantum dots

　　C　America adopted LEDs

　　D　graduate students work hard

　　E　quantum dot mixtures are magic

　　F　it is more efficient

　　答案与题解：

　　1.B　第一段第一句、第二句是关键。第一句说LED照明经济实惠，经久耐用。第二句说爱迪生的发明将被淘汰。其意思是LED将取代传统照明源，所以B是答案。

　　2.E　Bowers做实验，目的并非寻找新照明源。量子点在激光的激发下发出白光是一次意外的发现。段中用了“unexpected”和“surprised”都说明了这一点。第一段的“accidental discovery”也佐证了这是一次偶然的发现。因此，E是答案。

　　3.D　第五段列举了应用LED照朋的不少优点，如强亮度、经久耐用、低能量消耗、不易碎等。选项D的“LED lighting has many advantages”概括了本段的大意，所以D是答案。

　　4.C　由于有了量子点混合剂涂料，几乎任何物体都能用于照明。这是本段的中心思想。所以，C是答案。

　　5.F　题干涉及的内容在第五段可以找到，有关的句子是：“LEDs don’t emit heat, so they’re also more energy efficient”，很明显，F是答案。

　　6.A　选A的依据是第一段第一句、第二句。

　　7.B　与题干有关的内容在第三段第二句、第三句中可以找到。根据这两句表达的意思，B是答案。

　　8.C　题干的“29 percent of energy consumption for lighting could be saved by 2025”可在第五段第二句中找到。题干配上选项C后表达的意思与该句的意思相符，所以C是答案。

　　译文：发光二极管

　　日前公布的一项意外发现将发光二极管的研究推向新的高潮。这项研究显示，发光二极管与传统的电灯泡比起来，可能会更廉价、使用更持久。这项重大突破使人们看到，未来的趋势很可能是，爱迪生的发明将逐渐失去它的价值。目前发光二极管已被用于交通信号灯、手电筒和建筑照明，他们跟传统的电灯比起来更灵活，操作成本更低廉。

　　Vanderbilt大学的一名研究生 Michael Bowers正试图制造出一种非常小的量子点。这些量子点基本上都是晶体，且只有几毫微米大小，里面包含 100～1000个不等的光子。这些光子就是很容易激活的能量束，并且他们体积越小，能量越可能达到最强烈的程度。这些能量束中的每一个光点都异常小，只包括 33或 34对的原子。

　　当我们把光照射到量子点上或者给它们通上电，它们会有所反应，即发出自己的光，通常是一种耀眼的、振动的色彩。但当 Bowers把激光照在量子点上的时候，意想不到的事情发生了。当一种白色的光束照在桌子上时他惊呆了——这些量子点本应该发出蓝光的，但是相反的，他们发出的是美丽的白色光。

　　Bowers和另一个学生就此有了另一个想法，他们把聚亚安酯掺在这些量子点中，将混合物涂在一个蓝色的发光二极管灯泡上，这个看上去不怎么好看的灯泡发出了一种白色的光，跟我们普通用的灯泡极为相似。

　　发光二极管发出的光是普通 60瓦灯泡的两倍、且可以持续使用达 5万小时。据能源部估计，至 2025年，使用发光二极管照明会为美国节约 29%的能源。另外，发光二极管不会散热，这也有助于能源节约。与此同时。与传统灯泡比起来发光二极管更不易碎。

　　量子点混合物可以涂在任何事物的表层，通电后会产生一道道色彩，其中包括白色。我们未来的光源很可能不再是灯泡，相反地，它可以是任何东西，比如一张餐桌，一道墙，甚至是一支餐叉。

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（责任编辑：何莹莹）