冷原子与纳米碳管可聚集构成原子级“黑洞”
文章来源:未知 文章作者:meng 发布时间:2010-04-07 01:12 字体: [ ]  进入论坛
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Carbon nanotubes(碳纳米管) , long touted1(被吹捧的) for applications in materials and electronics, may also be the stuff of atomic-scale black holes. Physicists2 at Harvard University have found that a high-voltage nanotube can cause cold atoms to spiral(使成螺旋形) inward(内部,内脏) under dramatic acceleration3 before disintegrating4(分裂的,瓦解的) violently. Their experiments, the first to demonstrate something akin5 to(同类,近似) a black hole at atomic scale, are described in the current issue of the journal Physical Review Letters.

"On a scale of nanometers, we create an inexorable(不可阻挡的) and destructive pull similar to what black holes exert(运用,发挥) on matter at cosmic scales," says Lene Vestergaard Hau, Mallinckrodt Professor of Physics and of Applied6 Physics at Harvard. "As importantly for scientists, this is the first merging7 of cold-atom and nanoscale science, and it opens the door to a new generation of cold atom experiments and nanoscale devices."

Hau and co-authors Anne Goodsell, Trygve Ristroph, and Jene A. Golovchenko laser-cooled clouds of one million rubidium(铷) atoms to just a fraction of a degree above absolute zero. The physicists then launched this millimeter-long atomic cloud towards a suspended carbon nanotube, located some two centimeters away and charged to hundreds of volts8.

The vast majority of the atoms passed right by the wire, but those that came within a micron(微米) of it -- roughly 10 atoms in every million-atom cloud -- were inescapably attracted, reaching high speeds as they spiraled toward the nanotube.

"From a start at about 5 meters per second, the cold atoms reach speeds of roughly 1,200 meters per second, or more than 2,700 miles per hour, as they circle the nanotube," says Goodsell, a graduate student on the project and now a postdoctoral researcher in physics at Harvard. "As part of this tremendous acceleration, the temperature corresponding to the atoms' kinetic9 energy(动能) increases from 0.1 degrees Kelvin to thousands of degrees Kelvin in less than a microsecond."

At this point, the speeding atoms separate into an electron and an ion(离子) rotating in parallel around the nanowire, completing each orbit in just a few trillionths of a second. The electron eventually gets sucked into the nanotube via quantum tunneling(量子隧道贯穿) , causing its companion ion to shoot away -- repelled10 by the strong charge of the 300-volt nanotube -- at a speed of roughly 26 kilometers per second, or 59,000 miles per hour.

The entire experiment was conducted with great precision, allowing the scientists unprecedented11(空前的) access to both cold-atom and nanoscale processes.

"Cold-atom and nanoscale science have each provided exciting new systems for study and applications," says Golovchenko, Rumford Professor of Physics and Gordon McKay Professor of Applied Physics at Harvard. "This is the first experimental realization12 of a combined cold atom-nanostructure system. Our system demonstrates sensitive probing of atom, electron, and ion dynamics13(动力学,力学) at the nanoscale."

The single-walled carbon nanotube used in these researchers' successful experiment was dubbed14(被成为) "Lucy," and its contributions are acknowledged in the Physical Review Letters paper. The nanotube was grown by chemical vapor15 deposition16(化学气相沉积) across a 10-micron gap in a silicon17 chip that provides the nanowire with both mechanical support and electrical contact.

"From the atom's point of view, the nanotube is infinitely18 long and thin, creating a singular effect on the atom," Hau says.



点击收听单词发音收听单词发音  

1 touted 00151f908b31d984fd20d8b48dba34f3     
v.兜售( tout的过去式和过去分词 );招揽;侦查;探听赛马情报
参考例句:
  • She's being touted as the next leader of the party. 她被吹捧为该党的下一任领导人。
  • People said that he touted for his mother and sister. 据说,他给母亲和姐姐拉生意。 来自辞典例句
2 physicists 18316b43c980524885c1a898ed1528b1     
物理学家( physicist的名词复数 )
参考例句:
  • For many particle physicists, however, it was a year of frustration. 对于许多粒子物理学家来说,这是受挫折的一年。 来自英汉非文学 - 科技
  • Physicists seek rules or patterns to provide a framework. 物理学家寻求用法则或图式来构成一个框架。
3 acceleration ff8ya     
n.加速,加速度
参考例句:
  • All spacemen must be able to bear acceleration.所有太空人都应能承受加速度。
  • He has also called for an acceleration of political reforms.他同时呼吁加快政治改革的步伐。
4 disintegrating 9d32d74678f9504e3a8713641951ccdf     
v.(使)破裂[分裂,粉碎],(使)崩溃( disintegrate的现在分词 )
参考例句:
  • As a poetic version of a disintegrating world, this one pleased him. 作为世界崩溃论在文学上的表现,他非常喜欢这个学说。 来自辞典例句
  • Soil animals increase the speed of litter breakdown by disintegrating tissue. 土壤动物通过分解组织,加速落叶层降解的速度。 来自辞典例句
5 akin uxbz2     
adj.同族的,类似的
参考例句:
  • She painted flowers and birds pictures akin to those of earlier feminine painters.她画一些同早期女画家类似的花鸟画。
  • Listening to his life story is akin to reading a good adventure novel.听他的人生故事犹如阅读一本精彩的冒险小说。
6 applied Tz2zXA     
adj.应用的;v.应用,适用
参考例句:
  • She plans to take a course in applied linguistics.她打算学习应用语言学课程。
  • This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。
7 merging 65cc30ed55db36c739ab349d7c58dfe8     
合并(分类)
参考例句:
  • Many companies continued to grow by merging with or buying competing firms. 许多公司通过合并或收买竞争对手的公司而不断扩大。 来自英汉非文学 - 政府文件
  • To sequence by repeated splitting and merging. 用反复分开和合并的方法进行的排序。
8 volts 98e8d837b26722c4cf6887fd4ebf60e8     
n.(电压单位)伏特( volt的名词复数 )
参考例句:
  • The floating potential, Vf is usually only a few volts below ground. 浮置电势Vf通常只低于接地电位几伏。 来自辞典例句
  • If gamma particles are present, potential differences of several thousand volts can be generated. 如果存在γ粒子,可能产生几千伏的电位差。 来自辞典例句
9 kinetic p2Fxs     
adj.运动的;动力学的
参考例句:
  • There exist many sources of energy both potential and kinetic.存在着许多势能和动能的能源。
  • The kinetic theory of gases is the best known example.气体动力学理论就是最有名的例子。
10 repelled 1f6f5c5c87abe7bd26a5c5deddd88c92     
v.击退( repel的过去式和过去分词 );使厌恶;排斥;推开
参考例句:
  • They repelled the enemy. 他们击退了敌军。 来自《简明英汉词典》
  • The minister tremulously, but decidedly, repelled the old man's arm. 而丁梅斯代尔牧师却哆里哆嗦地断然推开了那老人的胳臂。 来自英汉文学 - 红字
11 unprecedented 7gSyJ     
adj.无前例的,新奇的
参考例句:
  • The air crash caused an unprecedented number of deaths.这次空难的死亡人数是空前的。
  • A flood of this sort is really unprecedented.这样大的洪水真是十年九不遇。
12 realization nTwxS     
n.实现;认识到,深刻了解
参考例句:
  • We shall gladly lend every effort in our power toward its realization.我们将乐意为它的实现而竭尽全力。
  • He came to the realization that he would never make a good teacher.他逐渐认识到自己永远不会成为好老师。
13 dynamics NuSzQq     
n.力学,动力学,动力,原动力;动态
参考例句:
  • In order to succeed,you must master complicated knowledge of dynamics.要取得胜利,你必须掌握很复杂的动力学知识。
  • Dynamics is a discipline that cannot be mastered without extensive practice.动力学是一门不做大量习题就不能掌握的学科。
14 dubbed dubbed     
v.给…起绰号( dub的过去式和过去分词 );把…称为;配音;复制
参考例句:
  • Mathematics was once dubbed the handmaiden of the sciences. 数学曾一度被视为各门科学的基础。
  • Is the movie dubbed or does it have subtitles? 这部电影是配音的还是打字幕的? 来自《简明英汉词典》
15 vapor DHJy2     
n.蒸汽,雾气
参考例句:
  • The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
  • This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。
16 deposition MwOx4     
n.免职,罢官;作证;沉淀;沉淀物
参考例句:
  • It was this issue which led to the deposition of the king.正是这件事导致了国王被废黜。
  • This leads to calcium deposition in the blood-vessels.这导致钙在血管中沉积。
17 silicon dykwJ     
n.硅(旧名矽)
参考例句:
  • This company pioneered the use of silicon chip.这家公司开创了使用硅片的方法。
  • A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。
18 infinitely 0qhz2I     
adv.无限地,无穷地
参考例句:
  • There is an infinitely bright future ahead of us.我们有无限光明的前途。
  • The universe is infinitely large.宇宙是无限大的。
TAG标签: electronics atoms nanotubes
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