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.
印度高温:热浪因何而起?何时结束?
怎样成为受欢迎的优步乘客
下一代苹果手机或将提高像素
调查表明:经常'秀恩爱'系缺乏自信?!
2015年英语四六级考试详细说明及评分标准
巴基斯坦假文凭公司CEO被捕
香港购物街门店租金将下滑近20%
广州香港已隔离65人:一张图带你了解MERS
福布斯最有影响力女性榜出炉
'岛主'成中国富人新头衔 你有岛么?
为亚洲大亨融资投资迅速飙升的股市
TransferWise办公室惊现员工桑拿房
珠峰九成冰川将于本世纪融化?
中国股市遭受重挫,跌幅超过6%
拒绝二手烟 北京全面禁止公共场合吸烟
肯尼亚律师爱上奥巴马千金
全球最低工资排行:澳洲公民最幸福
苹果高管暗示将进军电动汽车领域
喝咖啡也有最佳时间?
李克强总理出访拉美金句摘录
马拉多纳:梅西不如我,我的进球更漂亮!
'哆啦A梦'电影中国上映,'蓝胖子'或拉近中日关系
媒体批爸爸类“亲子节目”
四六级听力高频词语汇总
2015年6月英语六级考试时间分配
加拿大发明仿生镜片 8分钟让你达到超常视力
中国应该保持“战略定力”
2015年四级考试时间安排
法国男子狂喝56杯酒身亡
中国电影市场能否拯救"明日世界"
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |