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 / ’ɒbsəli:t/ adj．过时的，被淘汰的

flashlight / ’flæʃlaɪt/ n．手电筒

architectural / ,ɑ:kɪ’tektʃərəl / adj．建筑的

quantum / ’kwɒntəm / n．量子

crystal / ’krɪstl / n．晶体

batch / bætʃ/ n．一批

vibrant / ’vaɪbrənt /adj．（颜色）鲜明的

polyurethane / ,pɒlɪ’jʊərəθeɪn, -æn / n．聚亚安酯

lumpy / ’lʌmpɪ/ 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。

B　a laser excited the quantum dots

C　America adopted LEDs

D　graduate students work hard

E　quantum dot mixtures are magic

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

A:A B:B C:C D:D E:E F:F

“2025抵现”交易中新增（）功能.

A:对公-个人 B:个人-对公 C:对公-对公

2025年我国GDP预计将达到：（）

A:10万亿 B:20万亿 C:22万亿 D:50万亿

《中国制造2025》于2015年由（）印发。

A:全国人大代表 B:人民政协 C:国务院 D:最高人民法院

在使用2010－2025MHz频段进行TD组网时，通常室内分布站点使用（）

A:2010－2015MHz B:2015－2020MHz C:2020－2025MHz D:没有限制

下列程序段的输出结果为( )。
Dim M(5，5)，S(5)
For i=1 To 5
S(i)=0
For j=1 To 5
M(i，j)=i+j
S(i)=S(i)+M(i，j)
Next j
Next i
For Each x In s
Print x；
Next x

A:2023 24 3540 B:2025 30 3540 C:2023 25 3540 D:2025 354045

下列程序段的输出结果为( )。 Dim M(5，5)，S(5) For i=1 To 5 S(i)=0 For j=1 To 5 M(i，j)=i+j S(i)=S(i)+M(i，j) Next j Next i For Each x In s Print x； Next x

A:2023 24 3540 B:2025 30 3540 C:2023 25 3540 D:2025 354045

下列程序段的输出结果为( )。 Dim M(5,5), S(5) For i = 1 To 5 S(i) = 0 For j = 1 To 5 M(i, j) = i + j S(i) = S(i) + M(i, j) Next j Next i For Each x In S Print x; Next x

A:2023 24 3540 B:2025 30 3540 C:2023 25 35 40 D:2025 354045