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2015职称英语理工类概括大意预测题及答案(11)

2015-03-02 15:24

来源:新东方网整理

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  The Tiniest Electric Motor in the World

  1 Scientists recently made public the tiniest electric motor ever1 built. You could stuff hundreds of them into the period at the end of this sentence. One day a similar engine might power a tiny mechanical doctor that would travel through your body to remove your disease.

  2 The motor works by shuffling atoms between two molten metal droplets in a carbon nanotube. One droplet is even smaller than the other. When a small electric current is applied to the droplets, atoms slowly get out of the larger droplet and join the smaller one. The small droplet grows — but never gets as big as the other droplet and eventually bumps into the large droplet. As they touch, the large droplet rapidly sops up the atoms it had previously lost. This quick shift in energy produces a power stroke.2

  3 The technique exploits the fact that surface tension — the tendency of atoms or molecules to resist separating — becomes more important at small scales3. Surface tension is the same thing that allows some insects to walk on water.

  4 Although the amount of energy produced is small — 20 microwatts — it is quite impressive in relation to the tiny scale of the motor4. The whole setup5 is less than 200 nanometers on a side, or hundreds of times smaller than the width of a human hair. If it could be scaled up to the size of an automobile engine6, it would be 100 million times more powerful than a Toyota Camry's 225 horsepower V6 engine.

  5 In 1988, Professor Richard Muller and colleagues made the first operating micromotor, which was 100 microns across7, or about the thickness of a human hair. In 2003, Zettl's group created the first nanoscale motor. In 2006, they built a nanoconveyor, which moves tiny particles along like cars in a factory.

  6 Nanotechnology engineers try to mimic nature, building things atom-by-atom. Among other things, nanomotors could be used in optical circuits to redirect light, a process called optical switching. Futurists envision a day when nanomachines, powered by nanomotors, travel inside your body to find disease and repair damaged cells.

  词汇:

  shuffle /’ʃʌfl/ v.来回运动

  molten / ’məʊltən/ adj.溶化的

  droplet / ’drɒplɪt/ n.小滴

  nanoconveyor n.纳米传送带

  bump / bʌmp / v.碰撞

  sop / sɒp / v.吸入

  microwatt / ’maɪkrə(ʊ)wɒt / n.微瓦

  nanomachine n.纳米机器

  nanometer / ’nænəʊmi:tə(r)/ n.纳米,微毫米

  micromotor n.微电机

  nanotube n.纳米管

  nanotechnology n.纳米技术

  mimic / ’mɪmɪk / v.模仿

  stroke / strəʊk / n.行程,冲程

  nanomotor n.纳米发动机

  注释:

  1.ever:比以往任何时候,曾经。如:This is the best book I have ever read.这是我读过的书中最好的一本。

  2.power stroke:动力行程

  3.at small scales:在小等级上。这里指的是“在纳米等级上”。

  4.it is quite impressive in relation to the tiny scale of the motor:与电动机的小等级相比,功率是相当可观了。in relation to是“与……相比”。如:The city is quite large in relation to its

  population.就人口而言,这个城市相当的大。

  5.setup:装置。这里指nanomotor。

  6.If it could be scaled up to the size of an automobile engine:如果纳米电动机能按比例放大到汽车发动机的尺寸。scale ... up to是“把……按比例放大到……”。

  7.across:从一端到另一端

  练习:

  1.Paragraph 2 _____

  2.Paragraph 4 _____

  3.Paragraph 5 _____

  4.Paragraph 6 _____

  A An Introduction of a Toyota's 225 Horsepower V6 Engine

  B A Description of the Nanomotor in Terms of Power and Size

  C Surface Tension

  D Previous Inventions of Nanoscale Products

  E The Working Principle of the Nanomotor

  F Possible Fields of Application in the Future

  5.Doctors envision that the nanomotor would travel through human bodies to _____.

  6.Surface tension means the tendency of atoms or molecules to _____.

  7.Nanoconveyors could be used to _____.

  8.Applying a small electric current causes atoms to _____.

  A remove disease

  B resist separating

  C shuffle between two molten metal droplets

  D power nanomachines

  E sop up molecules from the large droplet

  F transport nanoscale objects

  答案与题解:

  1.E 第二段介绍了纳米发动机的工作原理。两小滴金属熔液通上微弱电流,大的小滴的原子就会缓慢逸出,加入小的小滴,后者体积不断增大,到一定阶段,就会与前者碰撞,这时,大的小滴便夺回它失去的原子,这就是一次power stroke(动力行程,动力冲程),此时就会产生发动机的动力。原子如此来来去去运动,就像发动机活塞一样。这就是纳米发动机的工作原理。所以,E是答案。

  2.B 第四段描述了纳米发动机的功率(20微瓦)和体积(200纳米)。选项B用“A description of the nanomotor in terms of power and size”概括本段大意,很准确,所以B是答案。

  3.D 第五段介绍了发明纳米发动机之前的一些纳米等级的机械产品,如体积大一些的纳米发动机,微型发动机,纳米传送带,纳米机器等。选项D概括了本段的大意,所以是答案。

  4.F 第六段预想了纳米发动机的用途,如用于光电路以改变光的方向(redirect light)和驱动纳米机器进入人体,消灭病灶。选项F是答案,因为“Possible fields of application in the future”概括了本段的大意。

  5.A 答案是A。题干出现doctors envision,选项的内容应与医学有关,选项A是remove disease,正好与题干的内容相配,是答案。短文第一段和最后一段也提到纳米发动机进入人体消灭病灶的可能性,证明选A是正确的。

  6.B 选B的依据是第三段第一句“surface tension—the tendency of atoms or molecules to resist separating—becomes more important at small scales”。

  7.F 题干的nanoconveyor提示我们,纳米传送带的功能自然是传送纳米等级的物体,所以F是答案。

  8.C 题干的Applying a small electric current ...在第二段能找到,该段讲的是纳米发动机的工作原理。如果了解原子在两小滴金属熔液中来回运动,产生动力,就会知道C是答案。

  世界上最小的电动机

  最近科学家公布了现有的最小的电动机。就是在这句话的句号里,你也能塞进几百个这样的电动机。将来有一天,类似的发动机也许能够为一个微型机械医生提供动力,在人的身体里自由移动,治疗疾病。

  发动机通过碳纳米管中的原子在两小滴金属溶液间来回运动进行工作。其中一个小滴甚至比另一个还要小。当微弱的电流通过时,大一点的小滴金属溶液中的原子就会缓慢逸出,进入小一点的小滴。这样,后者体积不断增大——但绝不会大到和前者一样——最后,与大一点的小滴金属溶液相撞。当它们接触时,大的小滴便夺回它失去的原子。能量这样迅速地来回运动就产生一次动力冲程。

  这项技术利用了表面张力的原理——原子或分子有不愿被分开的倾向——这在纳米等级上更加重要。表面张力同样也使某些昆虫能在水上行走。

  虽然这样产生的能量很少——只有20 微瓦,但与电动机的小等级相比,功率也是相当可现了。整个装置一侧的长度不到200纳米,比人类一根头发的宽度还要小几百倍。如果纳米电动机能按比例放大到汽车发动机的尺寸,它将会比丰田凯美瑞的225 马力的V6 引擎功率还要大1 亿倍。

  1988 年,理查德·乌勒教授和他的同事发明了第一台微型发动机, 100 微米长,或者说有一根头发那么粗。2003 年,泽特尔的小组制造出第一台纳米级的发动机。2006 年,他们又造出了纳米传送带,能够像工厂里传送汽车那样移动极小的粒子。

  纳米技术的工程师尽力去模拟自然,用一个个原子来制造物体。在这些事物当中,纳米发动机能够被用于光电路来改变光的方向,该过程被称为光学转换。未来主义者预想有一天,被纳米发动机驱动的纳米机器能在人体内移动,发现疾病并修复被破坏的细胞。

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