营养与食品卫生学
营养与食品卫生学
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。
5．just about anything：几乎任何东西。about = almost。A traditional lighting is less durable and dearerB 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 efficientOver 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”交易目前暂不支持（）账户参与交易。
A:信用卡 B:理财金卡 C:基本户
“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
“中国制造2025”和德国工业4.0的不同点有（）
A:中国制造业具有强大的技术基础，所以它直接实施工业4.0 B:中国在两化融合、信息化推动“互联网+”等各方面具有优势 C:中国任务比德国实现工业4.0更加复杂、更加艰巨 D:中国要实现传统产业转型升级，还要实现高端领域的跨越式发展
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
? ?下面有3篇短文，每篇短文后有5道小题。请根据短文内容，为每题确定1个最佳选项。
{{B}}第一篇{{/B}}
| ? ?
Crop Problem ? ?Advances in technology have helped more of the world’s population live better and longer, and that is part of our problem[ ? ?Better health standards have kept larger number of people alive. The world’s population is now almost four billion and expected to double in 25 years. Growing population and slowly rising living standards have increased our need for food at the rate of 30 million tons per year. As a result, the world’s stockpile of food(食物储备) is declining by about 10 million tons per year. ? ?From the early 1950s until 1972 ,world food production increased greatly. The Green Revolution (绿色革命) extended scientific techniques to agriculture in the form of hybrid seed (杂交种)and poultry (禽类), chemical fertilizers (化学肥料) and pesticides (杀虫剂), and complex irrigation systems. Strains (品种) of corn (玉米), sorghum (高粱), soybeans (大豆), wheat and rice were developed to flourish under particular climate and soil conditions. ? ?In the United States, corn production rose to 110 bushels(蒲式耳：谷物、水果、蔬菜等容量单位，在英国相当于36,368升，在美国相当于35,238升) per acre from only 26 bushels per acre in the early 1900s. Milk production rose to 10,000 pounds per cow per year, compared with 600 in India. Chickens were bred to eat less, grow to maturity in shorter time, and produce more eggs. As a result of such scientific advances, our twelve midwestern states alone now feed one fourth of the world’s people. ? ?Crop disaster in 1972 brought an apparent end to the growth in production. Much of the extra yields had come from the use of chemical fertilizers, primarily petroleum based and now in short supply. The drop in world supplies of petroleum-based fertilizers is expected to cause a drop in crop yields of ten tons for each one ton decline in fertilizers applied. ? ?This presents a particular problem for underdeveloped nations that often lack the foreign exchange necessary for buying fertilizer. The problem is so severe that Philip Handier, president of the National Academy of Sciences, has predicted one million child deaths per month in these nations by the year 2025. |
A:the United States will be able to feed half the world by 2025 B:the future will see no more hunger C:we will encounter very serious problem in the near future D:the developed nations will change in the near future
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