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四川省西昌市2016高考英语阅读理解和信息匹配类练习（9） 阅读下列四篇短文，从每小题后所给的A,B,C或D四个选项中，选出最佳选项。 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. | 
