EBatteries can power anything from small s

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问题:

E

Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri (MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

"To provide enough power, we need certain methods with high energy density(密度)" ,said Jae Kwon, assistant professor of electrical and computer engineering at MU. "The radioisotope (放射性同位素) battery can provide power density that is much higher than chemical batteries. "

Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro/nanoelectromechanical systems (M/NEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.

"People hear the word ’ nuclear’ and think of something very dangerous," he said, "However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems. "

His new idea is not only in the battery’ s size, but also in its semiconductor(半导体). Kwon’ s battery uses a liquid semiconductor rather than a solid semiconductor.

"The key part of using a radioactive battery is that when you harvest the energy, part of the ra- diation energy can damage the lattice structure (晶体结构) of the solid semiconductor," Kwon said, "By using a liquid semiconductor, we believe we can minimize that problem. "

Together with J. David Robertson, chemistry professor and associate director of the MU Re- search Reactor, Kwon is working to build and test the battery. In the future, they hope to increase the battery’ s power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

Liquid semiconductor is used to().

A. get rid of the radioactive waste

B. test the power of nuclear batteries

C. decrease the size of nuclear batteries

D. reduce the damage to lattice structure

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The Man of Many Secrets—Harry Houdini—was one of the greatest American entertainers in the theater next century. He was a man famous for his escapes—from prison cells, from wooden boxes floating in rivers, from locked tanks full of water. He appeared in theaters all over Europe and America. Crowds came to see the great Houdini and his "magic" tricks.

Of course, his secret was not magic, or supernatural powers. It was simply strength. He had the ability to move his toes as well as he moved his fingers. He could move his body into almost any position he wanted.

Houdini started working in the entertainment world when he was 17, in 1891. He and his brother Theo performed card tricks in club in New York. They called themselves the Houdini Brothers. When Harry married in 1894, he and his wife Bess worked together as magician and assistant. But for a long time they were not very successful. Then Harry performed his first prison escape, in Chicago in 1898. Harry persuaded a detective to let him try to escape from the prison, and he invited the local newspapermen to watch.

It was the publicity that came from this that started Harry Houdini’s success. Harry had fingers trained to escape from handcuffs and toes trained to escape ankle chins. But his biggest secret was how he unlocked the prison doors. Every time he went into the prison cell, Bess gave him a kiss for good luck—and a small skeleton key, which is a key that fits many locks, pass quickly from her mouth to his.

Harry used these prison escapes to build his fame. He arranged to escape from the local prison of every town he visited. In the afternoon, the people of the town would read about it in their local newspapers, and in the evening every seat in the local theater would be full. What was the result World-wild fame, and a name remembered today.

It can be inferred from the passage that Houdini became famous ().

A. in 1894

B. before he married

C. at the age of 17

D. when he was about 24

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要真正独立,就不该听他人的意见。

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在商业辐射区域内,各商场间位置的优劣主要取决于( )。

A.物业的易接近性

B.物业的临街状况

C.物业的周围环境

D.物业所处区域的繁华程度

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下列药物中可用溴量法测定含量的是()

A.水杨酸

B.司可巴比妥

C.枸橼酸钠

D.链霉素

E.苯巴比妥

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世界市场价格,也称国际市场价格,是指商品在世界市场上所形成的具有代表性的市场价格,世界市场价格的形成是以()的形成为前提的。

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