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The Tiniest Electric Motor in the World 1. Scientists recently made public the tiniest electric motor ever 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 (小滴) 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. 3. The technique exploits the fact that surface tension—the tendency of atoms or molecules to resist separating—becomes more important at small scales. 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 motor. The whole setup 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 engine, 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 micrometer, which was 100 microns across, 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. 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 Paragraph 2 ______
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Crystal Ear One day a friend asked my wife Jill if I wanted a hearing aid "He certainly does." replied Jill. After hearing about a remarkable new product, Jill finally got up the nerve to ask me if I’d ever thought about getting a hearing aid. "No way," I said. "It would make me look 20 years older." "No, no," she replied. "This is entirely different. It’s Crystal Ear!" Jill was right. Crystal Ear is different—not the old-styled body worn or over-the-ear aid, but all advanced personal sound system so small that it’s like contacts (隐形眼镜) for your ears. And Crystal Ear is super-sensitive and powerful, too. You will hear sounds your ears have been missing for years. Crystal Ear will make speech louder, and the sound is pure add natural. I couldn’t believe how tiny it is. It is smaller than the tip of my little finger and it’s almost invisible when worn. There are no wires, no behind-the-ear device. Put it in your ear and its ready-to-wear mold(形状) fits comfortably. Since it’s not too loud or too tight, you may even forget that you’re wearing it! Use it at work or at play. And if your hearing problem is worse in certain situations, use Crystal Ear only when you need it. Hearing loss, which occurs typically prior to teenage years, progresses throughout one’s lifetime. Although hearing loss is now the world’s number one health problem, nearly 90 percent of people suffering hearing loss choose to leave the problem untreated. For many millions, treating hearing loss in a conventional way can involve numerous office visits, expensive testing and adjustments to fit your ear. Thanks to Crystal Ear, the "sound solution" is now convenient. Almost 90 percent of people with mild hearing loss, and millions more with just a little hearing drop-off (下降), can be dramatically helped with Crystal Ear. More over, its superior design is energy-efficient, so batteries can last months. Crystal Ear is now available to help these people treat their hearing loss with a small hearing amplifier (放大器). Initially the writer did not want to buy a hearing aid because ______.
U.S. Blacks Hard Hit by Cancer Death rates for cancer are falling for all Americans. But black Americans are still more likely to die of cancer than whites, the American Cancer Society said Monday. In a special report on cancer and blacks, the organization said blacks are usually diagnosed with cancer later than whites, and they are more likely to die of the disease. This could be because of unequal (不平等的) access to medical Care. Because blacks are more likely to have other diseases as well, and perhaps because of differences in the biology (生物学) of the cancer itself, the report added. "In general, black Americans have less hope of surviving five years after diagnosis than whites for all cancer sites and all stages of diagnosis." the report said. "In describing cancer statistics for black Americans, this report recognizes that many of the differences associated with race may be caused by unfair social and economic differences and unequal access to medical care." The cancer society said blacks should be encouraged to get check-ups (体格检查) earlier, when cancer is more treatable. And it said more research is needed to see if biological differences play a role. "The new statistics emphasize the continuing importance of wiping out these unfair social differences through public policy and education efforts," the organization said in a statement. But it also noted a drop in cancer death rates. "Cancer death rates in both sexes for all sites combined have dropped greatly among black Americans since 1992, as have incidence rates (发生率)," said the report. Black Americans are more likely to die of cancer than ______.
Mother Nature Shows Her Strength Tornadoes (龙卷风) and heavy thunderstorms moved across the Great Lakes and into Trumbull County on Saturday evening. The storms were dramatic and dangerous. George Snyder was driving the fire truck down Route 88 when he first noticed that a funnel (漏斗状的) cloud was behind him. "I stopped the truck and watched the funnel cloud. It was about 100 feet off the ground and I saw it go up and down for a while. It was moving toward Bradley Road and then suddenly it disappeared." Snyder said. Snyder only saw one of the funnel clouds that passed through northeastern Ohio on Saturday. In Trumbull County, a tornado turned trees onto their sides. Some trees feel onto houses and Cars. Other trees fell into telephone and electrical wires as they went down. Amanda Symcheck was having a party when the storm began. "I knew something was wrong," she said. "I saw the sky go green and pink (粉红色的). Then it sounded like a train rushing toward the house. I started crying and told everyone to go to the basement for protection." The tornado caused a lot of damage to cars and houses in the area. It will take a long time and much money to repair everything. There was also serious water damage from the thunderstorms. The heavy rains and high wind caused the power to go out in many homes. The storms caused serious flooding in areas near the river. More than four inches of rain fell in parts of Trumbull County. The river was so hight that the water ran into streets and houses. Many streets had to be closed to cars and trucks because of the high water. This made it difficult for fire trucks, police cars, and other rescue vehicles to help people who were in trouble. Many people who live near the river had to leave their homes for their own safety. Some people reported five feet of water in their homes. Local and state officials opened emergency shelters for the people who were evacuated (撤走). The Red Cross served meals to them. "This was a really intense storm." said Snyder. People were afraid. MotherNature call be fierce. We were lucky this time. No one was killed." George Snyder was a firefighter.
Unpopular Subjects Is there a place in today’s society for the study of useless subjects in our universities Just over 100 years ago Fitzgerald argued in a well-written letter 1 Nature that "Universities must be allowed to study useless subjects— 2 they don’t, who will He went on to use the 3 of Maxwell’s electrodynamics (电动力学) as one case where a "useless subject" has been transformed to a useful subject. Nowadays this argument is again very much 4 in many universities. Indeed one suspects that it is one of those arguments that must be 5 anew (重新) by each generation. But now there is an added twist subjects must not only be useful, they must also be 6 enough that students will flock (蜂拥) to do them, and even flock to pay to do them. As universities become commercial operations, the pressure to 7 subjects or departments that are less popular will become stronger and stronger. Perhaps this is most strongly 8 at the moment by physics. There has been much 9 in the press of universities that are closing down physics departments and incorporate them with mathematics or engineering departments. Many scientists think otherwise. They see physics as a 10 science, which must be kept alive if only to 11 a base for other sciences and engineering. It is of their great personal concern that physics teaching and research is under 12 in many universities. How Can it be preserved in the rush towards commercial competition A major turnaround (转变) in student popularity may have to 13 until the industrial world discovers that it needs physicists and starts paying them well. Physics is now not only unpopular; it is also "hard". We can do more about the latter by 14 teaching in our schools and universities. We can also 15 cooperative arrangements to ensure that physicists keep their research and teaching up to date.
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