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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&39;s bright invention 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 electrons. They&39;re easily excited bundles of energy, and the smaller they are, the more excited they get. Each dot in Bowers&39; 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 light, 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&39;t pretty, but it produced white light similar to a regular light bulb. 5 LEDs produce twice as much light as a regular 60 watt bulb and burn 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&39;t emit heat, so they&39;re also more energy efficient. And they&39;re much harder to break. 6 Quantum dot mixtures could be painted on just about anything 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. Paragraph 1 ______ A LED Lighting Is Not MatureB LED Lighting Will Replace Traditional LightingC Almost Everything Could Be the Main Light Source in the FutureD LED Lighting Has Many AdvantagesE Bowers Made an Unexpected DiscoveryF LED Light Bulbs Look Lumpy Paragraph 3 ______ A LED Lighting Is Not MatureB LED Lighting Will Replace Traditional LightingC Almost Everything Could Be the Main Light Source in the FutureD LED Lighting Has Many AdvantagesE Bowers Made an Unexpected DiscoveryF LED Light Bulbs Look Lumpy Paragraph 5 ______ A LED Lighting Is Not MatureB LED Lighting Will Replace Traditional LightingC Almost Everything Could Be the Main Light Source in the FutureD LED Lighting Has Many AdvantagesE Bowers Made an Unexpected DiscoveryF LED Light Bulbs Look Lumpy Paragraph 6 ______ A LED Lighting Is Not MatureB LED Lighting Will Replace Traditional LightingC Almost Everything Could Be the Main Light Source in the FutureD LED Lighting Has Many AdvantagesE Bowers Made an Unexpected DiscoveryF LED Light Bulbs Look Lumpy Unlike traditional lighting, LEDs do not give out heat so ______. A traditional lighting is less durable and dearerB a laser excited the quantum dotsC America adopted LEDsD graduate students work hardE quantum dot mixtures are magicF it is more efficient Edison&39;s bright invention is likely to be outdated because ______. A traditional lighting is less durable and dearerB a laser excited the quantum dotsC America adopted LEDsD graduate students work hardE quantum dot mixtures are magicF it is more efficient Something unexpected happened during Bower&39;s experiment when ______. A traditional lighting is less durable and dearerB a laser excited the quantum dotsC America adopted LEDsD graduate students work hardE quantum dot mixtures are magicF it is more efficient Over one quarter of energy consumption for lighting could be saved by 2025 if ______. A traditional lighting is less durable and dearerB a laser excited the quantum dotsC America adopted LEDsD graduate students work hardE quantum dot mixtures are magicF it is more efficient
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【简答题】A.Basketball. B.Football. C.Baseball. D.Golf.
【单选题】机动车辆保险车损险不包括( )责任。
A.
碰撞导致的车损
B.
非碰撞导致的车损
C.
运动中产生的车损
D.
碰撞导致的对方车辆损失
【单选题】对于CRH值分别为82%、71%的两种水溶性粉末制备散剂时,混合物的生产和贮藏环境的湿度应控制在( )
A.
82%以下
B.
76%以下
C.
71%以下
D.
58%以上
E.
58%以下
【单选题】机动车辆保险通常不包括( )。
A.
车辆损失保险
B.
第三者责任保险
C.
附加保险
D.
附加盗窃
【判断题】在双代号时标网络图中,水平波形线表示自由时差。 ( )
A.
正确
B.
错误
【单选题】某钢筋混凝土框架剪力墙结构为二类工程项目,按照“营改增”费用定额的调整内容,管理费的费率为29%,利润的费率为12%,该项目的有梁板采用C30预拌混凝土泵送,则清单组价时应选择的定额子目及其综合单价为( )。(除管理费费率执行营改增调整,其他均按2014计价定额执行)
A.
6-207 , 461.46 元 /m 3
B.
6-207 , 463.74 元 /m 3
C.
6-331 , 452.21 元 /m 3
D.
6-331 , 454.50 元 /m 3
【简答题】American football and baseball are becoming known to the British public through televised ________ from the United States. A) transfer B) deliveries C) transportation D) transmissions
【单选题】在机动车辆保险中,对于意外事故或自然灾害所致损失,保险人所负的保险责任不包括()。
A.
保险车辆与外界物体的意外撞击造成的本车损失
B.
保险车辆所装货物与外界物体的意外撞击造成的本车损失
C.
驾驶人故意碰坏车旁的另一辆车
D.
保险车辆在停车场停车后退时撞坏挡泥板
【单选题】在我国,机动车辆保险基本险分为车辆损失保险和第三者责任险。其中,在机动车辆损失险中,保险公司不予承担赔偿责任的损失包括( )等。
A.
受本车所载货物撞击的损失
B.
外界物体倒塌造成的本车损失
C.
所装货物与外界物体意外撞击造成的损失
D.
保险车辆与外界物体的意外撞击造成的本车损失
【单选题】钨极氩弧焊要求氩气纯度应达到( ).
A.
0.95
B.
0.99
C.
0.999
D.
0.9999
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