彭蒙惠英语:20110214 MP3在线课程 NEWSworthy Clips

时间 : 2013-12-12 07:06来源 : VOA官网 收听下载次数 :
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Diamonds cutting environmental impact

by Takashi Hagiwara / (c) 2010, The Yomiuri Shimbun. Distributed by McClatchy-Tribune Information Services.

Diamonds are known as a girl's best friend due to their splendid sparkle, but they are also held in very high regard by industrialists, who prize their unmatched density, excellent therm al conduction and other properties.

Exploiting these unique properties is the key to a new kind of sem iconductor that researchers hope could be a revolutionary advance in energy-efficient technology.The artificial diamond super semiconductor is being developed by the Diamond Research Laboratory of the National Institute of Advanced Industrial Science and Technology (AIST) in Japan.

Artificial diamonds are most commonly produced by decomposing m ethane gas in a microwave oven at temperatures of about 1,000 degrees Celsius. This process produces minute flakes of carbon, which pile up like accumulated snow to form a thin layer, or lam inate, of diamond.

The AIST team has found a way to accelerate that process and can efficiently produce diamond laminates measuring 2.3 centimeters square and 0.4 millimeter thick─a size that ranks alongside the largest artificial diamonds produced.

While diamond has natural insulating qualities, adding minute amounts of boric acid and some other substances during the methane-decomposition process produces a diamond that also acts as an excellent semiconductor.

The AIST team [in 2009] created a prototype semiconductor element measuring 1.6 centimeters square. If about 10 such elements were combined to form one large element, it would be suitable for use in the power control system of a hybrid vehicle, said Shinichi Shikata, 56, who heads the AIST team.

A hybrid car equipped with such technology would consume about 960 kilowatt hours less per year than a conventional hybrid.

If every hybrid vehicle currently in use worldwide had such a system in place, their collective carbon dioxide emissions would be reduced by about 5 million tons over 40 years, he said.

"We'd like to see diamond semiconductors become commonplace some day, since they would be sure to help realize a low-carbon society."

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钻石降低环境冲击

钻石因为耀眼夺目而被称为女人最好的朋友, 但也深受工业家的重视。他们看重的是钻石无与伦比的密度、绝佳的导热性以及其他特质。

研发一种新式半导体的关键,正是充分利用这些独特的性质。研究人员期盼这种半导体能够为节能科技带来革命性的进展。

人造钻石超级半导体的研发机构是日本产业技术综合研究所(产综研)的钻石研究实验室。

人造钻石最常见的制造方法是利用温度可达摄氏一千度的微波炉分解甲烷气体。这种程序可制造出碳的细微碎片,像积雪一样堆叠成钻石薄层,或称为层压片。

产综研的团队找出了一种方法,能够加速这项程序,并且能够极有效率地产生面积达二点三平方公分、厚零点四公釐的钻石层压片──大小相当于当前世界上最大的人造钻石。

钻石虽然具有天然绝缘的特性,但只要在甲烷分解过程中加入微量的硼酸及一些其他物质,产生的钻石即可成为优异的半导体。

产综研的团队在二00九年制造出一件半导体元件原型,面积为一点六平方公分。只要把约十件这种元件结合成一个大型元件,即可用于油电混合车辆的电力控制系统当中,五十六岁的鹿田真一表示。他是产综研团队的领导人。

配备这种科技的油电混合车每年消耗的电量将可较传统油电混合车减少约九百六十度。

当前世界上的油电混合车如果全都配备有这样的系统, 其二氧化碳排放总量将可在四十年内减少五百万吨左右,他如此表示。

「我们希望钻石半导体有朝一日能够普及,因为这种半导体绝对有助于实现低碳社会的理想。」

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