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  3. Solar Power without Solar Cells A dramatic and surprising magnetic effect of light discovered by University of Michigan rese

Solar Power without Solar Cells A dramatic and surprising magnetic effect of light discovered by University of Michigan rese

admin2012-12-28  48
问题                     Solar Power without Solar Cells
    A dramatic and surprising magnetic effect of light discovered by University of Michigan researchers could lead to solar power without traditional semiconductor-based solar cells.
    The researchers found a way to make an "optical【C1】______," said Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics.
    Light has electric and magnetic【C2】______Until now, scientists thought the effect of the magnetic field were so weak that they could be【C3】______What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not【C4】______electricity, the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop strength【C5】______to a strong electric effect.
    "This could lead to a new kind of solar cell without semiconductors and without absorption to produce charge separation," Rand said. "In solar cells, the【C6】______goes into a material, gets absorbed and creates heat. " Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power【C7】______What makes this possible is a previously undetected brand of "optical rectification," says William Fisher, a doctoral student in applied physics. In traditional optical rectification, light’s electric field causes a charge separation, or a pulling【C8】______of the positive and negative charges in a material. This sets up a voltage, similar to【C9】______in a battery.
    Rand and Fisher found that under the right circumstances and in right types of materials, the light’s magnetic field can also create optical rectification. The light must be shone through a【C10】______that does not conduct electricity, such as glass. And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn’t this【C11】______on its own, but new materials are being sought that would work at lower intensities, Fisher said.
    "In our most recent paper, we show that incoherent light like sunlight is theoretically almost 【C12】______effective in producing charge separation as laser light is," Fisher said.
    This new【C13】______could make solar power cheaper, the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in converting solar power to useable energy. That’s equivalent to today’s commercial-grade solar cells.     "To manufacture modern solar cells, you have to do【C14】______semiconductor processing," Fisher said. "All we would need are lenses to focus the light and a fiber to guide it. Glass works for【C15】______It’s already made in bulk, and it doesn’t require as much processing. Transparent ceramics might be even better. "
【C9】
选项 A、this
B、those
C、that
D、these
答案C
解析 本题考查上下文语义。从上下文判断，要填入的代词是替代前面的voltage。根据英语语法，替代单数名词的代词要用that，替代复数名词的代词要用those。voltage是单数，所以that是答案。
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