Although it symbolises a bright idea, the traditional incandescent light bulb is a dud. It wastes huge amounts of electricity, radiating 95% of the energy it consumes as heat rather than light. Its life is also relatively short, culminating in a dull pop as its filament fractures. Now a team of researchers has devised a light bulb that is not only much more energy-efficient it is also expected to last longer than the devices into which it is inserted. Moreover, the lamp could be used for rear-projection televisions as well as general illumination.
The trick to a longer life, for light bulbs at least, is to ensure that the lamp has no electrodes. Although electrodes are undeniably convenient for plugging bulbs directly into the lighting system, they are also the main reason why lamps fail. The electrodes wear out. They can react chemically with the gas inside the light bulb, making it grow dimmer. They are also difficult to seal into the structure of the bulb, making the rupture of these seals another potential source of failure.
Scientists working for Ceravision, a company based in Milton Keynes, in Britain, have designed a new form of lamp that eliminates the need for electrodes. Their device uses microwaves to transform electricity into light. It consists of a relatively small lump of aluminium oxide into which a hole has been bored. When the aluminium oxide is bombarded with microwaves generated from the same sort of device that powers a microwave oven, a concentrated electric field is created inside the void.
If a cylindrical capsule containing a suitable gas is inserted into the hole, the atoms of the gas become ionised. As electrons accelerate in the electric field, they gain energy that they pass on to the atoms and molecules of the gas as they collide with them, creating a glowing plasma. The resulting light is bright, and the process is energy-efficient. Indeed, whereas traditional light bulbs emit just 5% of their energy as light, and fluorescent tubes about 15%, the Ceravision lamp has an efficiency greater than 50%.
Because the lamp has no filament, the scientists who developed it think it will last for thousands of hours of use in other words, for decades. Moreover, the light it generates comes from what is almost a single point, which means that the bulbs can be used in projectors and televisions. Because of this, the light is much more directional and the lamp could thus prove more efficient than bulbs that scatter light in all directions. Its long life would make the new light ideal for buildings in which the architecture makes changing light bulbs complicated and expensive. The lamps small size makes them comparable to light-emitting diodes but the new lamp generates much brighter light than those semiconductor devices do. A single microwave generator can be used to power several lamps.
Another environmental advantage of the new design is that it does not need mercury, a highly toxic metal found in most of the bulbs used today, including energy-saving fluorescent bulbs, fluorescent tubes and the high-pressure bulbs used in projectors. And Ceravision also reckons it should be cheap to make. With lighting accounting for some 20% of electricity use worldwide, switching to a more efficient system could both save energy and reduce emissions of climate-changing greenhouse gases.
上一篇: 考研英语阅读理解精读100篇UNIT10
下一篇: 考研英语阅读理解精读100篇UNIT25
2017届高考英语一轮全册复习学案:Unit3《Celebration》(北师大版)
2017届高考英语一轮复习专题强化训练:专题3 动词的时态和语态(含解析)
2017届高考英语一轮全册复习学案:Unit2《Heroes》(北师大版)
2017届高考英语一轮复习专题强化训练:专题2 阅读理解 第5讲专题强化训练(含解析)
2017届高考英语一轮复习专题强化训练:专题5 语法填空 专题强化训练(含解析)
2017届高考英语一轮全册复习学案:Unit22《Environmental Protection》(北师大版)
2017届高考英语一轮全册复习学案:Unit23《Conflict》(北师大版)
2017届高考英语一轮复习语法专练课件:4 定语从句(牛津译林版)
2017届高考英语一轮全册复习学案:Unit1《Lifestyles》(北师大版)
国内英语资讯: Beijing issues smog alert
2017届高考英语一轮复习语法专练课件:7 形容词和副词(牛津译林版)
跟Hello Kitty说拜拜:现在日本白领爱的是这只愤怒小熊猫
2017届高考英语一轮全册复习学案:Unit19《Language》(北师大版)
2017届高考英语一轮复习专题强化训练:专题5 语法填空 跟踪训练(含解析)
2017届高考英语一轮复习语法专练课件:6 名词、冠词和代词(牛津译林版)
2017届高考英语一轮全册复习学案:Unit21《Human Biology》(北师大版)
2017届高考英语一轮全册复习学案:Unit24《Society》(北师大版)
2017届高考英语一轮复习语法专练课件:2 非谓语动词(牛津译林版)
2017届高考英语一轮复习专题强化训练:专题5 定语从句(含解析)
电子书销量持续下滑 年轻一代爱上纸质书
2017届高考英语一轮全册复习学案:Unit20《New Frontiers》(北师大版)
体坛英语资讯:Bayern, Schalke win in German Bundesliga
2017届高考英语一轮复习专题强化训练:专题4 完形填空 跟踪训练(含解析)
2017届高考英语一轮复习专题强化训练:专题7 书面表达 跟踪训练(含解析)
“皮皮虾我们走!”用英语怎么说?
2017届高考英语一轮复习语法专练课件:9 情态动词和虚拟语气(牛津译林版)
国际英语资讯:Hindu saint sworn in as chief minister of Indias most populous state of Uttar Pradesh
2017届高考英语一轮全册复习学案:Unit4《Cyberspace》(北师大版)
体坛英语资讯:14th Cameroon International Cycling Tour concludes in Yaounde
2017届高考英语一轮复习专题强化训练:专题7 并列句和状语从句(含解析)