2013考研英语阅读100篇及剖析(二十二)_大学英语阅读

2013考研英语阅读100篇及剖析(二十二)

　　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.