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  3. Solar Power without Solar Cells A dramatic and surprising magnetic effect o...

Solar Power without Solar Cells A dramatic and surprising magnetic effect o...

admin2020-12-24  29
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 ceils.
The researchers found a way to make an “optical (光的）_____ (51)，” said Stephen Rand，a professor in the departments of Electrical Engineering and Computer Science，Physics and Applied Physics.
Light has electric and magnetic _____ (52) . Until now, scientists thought the effects of the magnetic field were so weak that they could be_____(53). What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not (54) electricity，the light field can generate magnetic effects that are 100 m川ion times stronger than previously expected. Under these circumstances，the magnetic effects develop strength _______(55) 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______(56) 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______(57) .” What makes this possible is a previously undetected brand of “ optical rectification (修正），” says William Fisher，a doctoral student in applied physics. In traditional opticd rectification，light’s electric field causes a charge separation，or a pulling _______(58) of the positive and negative charges in a material. This sets up a voltage，similar to _______(59) 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_____ (60) 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______(61) on its own，but new materials are being sought that would work at lower intensities，Fishersaid.
“In our most recent paper，we show that incoherent (非相干的）light like sunlight is theoretically almost ______ (62) effective in producing charge separation as laser light is，” Fisher said.
This new ______(63) could make solar power cheaper, the researchers say.They predict that with improved materials they codd achieve 10 percent efficiency in converting solar power to useable energy. That’s equivalent to today’s commercial solar cells.
“To manufacture modem solar cells, you have to do ______ (64) semiconductor processing,” Fisher said. “All we would need are lenses to focus the light and a fiber to guide it. Glass works for ______ (65). It’s already made in bulk, and it doesn’t require as much processing. Transparent ceramics (陶瓷材料）might be even better. ”
选项 A that
B this
C those
D these
答案A
解析that指代前面命voltage。
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