大学六级-1367及答案解析.doc
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1、大学六级-1367 及答案解析(总分:712.00,做题时间:90 分钟)一、Part Writing(总题数:1,分数:106.00)1.Evaluation by Students1不少大学让学生参与任课老师教学情况的测评2对此改革措施校方、教师、学生的看法不一3学生测评教师的益处以及可能产生的问题(分数:106.00)_二、Part Reading Compr(总题数:1,分数:70.00)The Wonderful World of SmallTheres a quiet revolution going on, and its name is nanotechnology. A ho
2、st of innovations are coming our way. Some seem almost magical, like the new material created in 2004 by Ray Baughman, a professor at the University of Texas. Its stronger than steel, transparent, very, very light. A hectare-size sheet would weigh just 280 grams.When the professor announced that he
3、hadnt decided what to call it, he started to get emails from around the world suggesting names. Since it was so light and strong, people started calling it “mithril“ the name of a highly prized type of armor used in The Lord of Rings.There are other discoveries too perhaps not so astounding, but pra
4、ctical and pleasant. Now there are socks that dont get smelly, pants that resist stains, windows that repel dirt and toilets that clean themselves. All this results from exploring the world of the very, very small.Nano comes from the Greek word from dwarf. Usually nanotechnology is defined as the st
5、udy and manipulation of matter smaller than 100 nanometers (纳米) thats the scale of things like molecules and viruses. Ten hydrogen atoms pressed together against each other are just one nanometer long. And one million nanometers fit into a millimeter. Hard to grasp? Think of it this way: If everyone
6、 in Manila were a nanometer wide, the entire population, standing shoulder to shoulder, would fit on your thumbnail.Stunning Uses of NanotechnologyLike Alice in Wonderland, researchers in Nanoland find themselves in a world where old rules dont apply. Small things behave differently. This is behind
7、several innovations, including the self-cleaning toilet. The toilet bowl is sealed with a super-smooth glaze (涂层) that has microscopic holes under 30 nanometers. Because theyre smaller than bacteria or other tiny particles, theres not enough room for dirt to get stuck in the surface. Flushing is bas
8、ically all the work you have to do.Researchers in Nanoland are also making really, really small things with astonishing properties like the carbon nanotube. Chris Papadopoulos of the University of Victoria, says, “The carbon nanotube is the poster boy for nanotechnology.“In your pencil, carbon, in t
9、he form of graphite (石墨), is soft and easily broken. But a carbon nanotube is tough as nails much tougher in fact. Its very thin sheet graphite thats formed into a tube. These tiny straw-like cylinders, which can be as small as half a nanometer wide, are up to 100 times stronger than steel and six t
10、imes lighter. They are the hardest, stiffest, strongest materials known and are among the worlds best conductors of heat and electricity. They can carry some 1,000 times more electricity current than copper wire: Everybody wants them, but until now theyve been in short supply and pricey. The current
11、 annual production, worldwide, is only 300 kilograms. At 860 a gram, carbon nanotubes cost 50 times more than gold.When it comes to finding uses for carbon nanotubes, the range is huge. The National Research Council Canada (NRC) is looking at harnessing their strength by embedding them in constructi
12、on materials, among other applications. The Boeing Company thinks nanotubes may be the source of futute improvements for high-performance aircraft. Some of the most stunning uses come out of Ray Baughmans research. Employing what he calls the “ancient technology of spinning“, Baughrnan and his team
13、developed a way of spinning carbon nanotubes into fibers that are four times tougher than spider silk, the toughest natural filament (细丝). Since they also conduct electricity, the futuristic yarns could be woven into “smart“ clothing that stores electricity, is potentially bulletproof and incorporat
14、es sensors capable of adjusting the temperature of garment. The fibers could also be made into cables for suspension bridges much longer than any we have now.And then there are Baughmans superstrong, superlight sheets. Papadopoulos explains that one of the reasons scientists are oxcited by the sheet
15、s is that they would make ideal solar sails. He says, “With a solar sail, you are allowing the pressure of the suns light to propel you through space the same way wind powers a sailboat.“ But there is also something in this for the earthbound traveler. Using an ordinary microwave oven, Baughmans tea
16、m was able to weld one of his sheets between two pieces of plexiglass (树脂玻璃). Afterwards, it still conducted electricity and remained transparent. One idea, therefore, is to put these sheets in windshields of the car and run current through them to defrost car windows.Medicine and NanotechnologyMany
17、 disease-causing bacteria and viruses are nano size. So only nanotechnology would offer us ways of fighting back. Nucryst Pharmaceuticals has come up with a winning formula that combines nanoscience with old-fashioned folk wisdom. The ancient Greeks used silver to promote healing and prevent infecti
18、on, but the treatment took a back seat when antibiotics came on the scene. Nucryst has revived and improved on the old cure by coating a burn-and-wound bandage with nano-size silver particles that are more reactive than the bulk form of metal. They penetrate into the skin and work steadily. As a res
19、ult, burn victims can have their dressings changed as little as once a week. Before Nucryst, such dressings had to be changed several times a day, a painful procedure that involved removing a healing cream.In 2004, Nucryst produced over three million bandages, and its sales topped 30 million. 70% of
20、 chronic-wound patients who were not healing at the expected rate got better with the use of these bandages.Copy Nature with NanoteehnologyWith new instruments that reveal natural structures down to the last atom, nanotechnologists ability to copy nature has taken off. When Bharat Bhushan, a mechani
21、cal engineering professor at Ohio State University, wanted to make a super-smooth surface, he decided to copy lotus leaves. Scientists have long known that the leaves shed water very well: Theyre waxy and covered with tiny nano-size bumps, so water rolls off. Bhushan succeeded in making a polymer (聚
22、合体) sheet that was equally smooth. “If you applied it to glass, you could have windows that dont need washing.“ says Bhushan.Hicham Fenniri, a chemistry professor at the Univeristy of Alberta, took a similar tack to make artificial joints act more like natural ones. The body recognizes an artificial
23、 hip or knee as foreign and may reject it. In most cases, the implant can become loose and painful and has to be replaced. But Fenniri has made a nanotube coating for the artificial joint. Its a very good imitation of collagen (原质), a natural protein that is part of bone. As a result, the coating at
24、tracts bone cells. This is important because bone growth helps integrate an artificial joint into the body. Says Fenirri, “You need to attract the right cells to the right places, right away. Speed is essential when incorporating an artificial joint into the body.“(1,146 words)(分数:70.00)(1).In 2004,
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- 大学 1367 答案 解析 DOC
