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Solar Power Without Solar CellsA 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 1 "said Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics.Light has electric and magnetic components. Until now, scientists thought the 2 of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than 3 expected. 4 these circumstances, the magnetic effects develop strength equivalent 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 5 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 6 ." 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 7 of the positive and negative charges in a material. This sets up a voltage, similar to 8 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 9 that does not 10 electricity, such as glass. And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn"t this intense 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 as 11 in producing charge separation as laser light is," Fisher said."This new 12 could make solar power cheaper, "the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in 13 solar power to useable energy. That"s equivalent to today"s commercial-grade solar cells."To manufacture 14 solar cells, you have to do extensive semiconductor processing," Fisher said. "All we would need are lenses to focus the light and a fiber to guide it. Glass works for 15 . It"s already made in bulk, and it doesn"t require as much processing. Transparent ceramics might be even better."
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Solar Power Without Solar CellsA 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 1 "said Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics.Light has electric and magnetic components. Until now, scientists thought the 2 of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than 3 expected. 4 these circumstances, the magnetic effects develop strength equivalent 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 5 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 6 ." 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 7 of the positive and negative charges in a material. This sets up a voltage, similar to 8 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 9 that does not 10 electricity, such as glass. And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn"t this intense 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 as 11 in producing charge separation as laser light is," Fisher said."This new 12 could make solar power cheaper, "the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in 13 solar power to useable energy. That"s equivalent to today"s commercial-grade solar cells."To manufacture 14 solar cells, you have to do extensive semiconductor processing," Fisher said. "All we would need are lenses to focus the light and a fiber to guide it. Glass works for 15 . It"s already made in bulk, and it doesn"t require as much processing. Transparent ceramics might be even better."
Solar Power Without Solar CellsA 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 1 "said Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics.Light has electric and magnetic components. Until now, scientists thought the 2 of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than 3 expected. 4 these circumstances, the magnetic effects develop strength equivalent 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 5 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 6 ." 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 7 of the positive and negative charges in a material. This sets up a voltage, similar to 8 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 9 that does not 10 electricity, such as glass. And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn"t this intense 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 as 11 in producing charge separation as laser light is," Fisher said."This new 12 could make solar power cheaper, "the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in 13 solar power to useable energy. That"s equivalent to today"s commercial-grade solar cells."To manufacture 14 solar cells, you have to do extensive semiconductor processing," Fisher said. "All we would need are lenses to focus the light and a fiber to guide it. Glass works for 15 . It"s already made in bulk, and it doesn"t require as much processing. Transparent ceramics might be even better."
Milosevic"s DeathFormer Yugoslav leader Slobodan Milosevic was found dead last Saturday in his cell at the Hague-based International Criminal Tribunal for the former Yugoslavia. The 64-year-old had been on trial there since February 2002.Born in provincial Pozarevac in 1941, he was the second son of a priest and a school teacher. Both of his parents died when he was still a young adult. The young Milosevic was "untypical", says Slavolub Djukic, his unofficial biographer. He was "not interested in sports, avoided excursions (短途旅行) and used to come to school dressed in the old-fashioned way—white shirt and tie." One of his old friends said, he could "imagine him as a station-master or punctilious (一丝不苟) civil servant."Indeed that is exactly what he might have become, had he not married Mira. She was widely believed to be his driving force.At university and beyond he did well. He worked for various firms and was a communist party member. By 1986 he was head of Serbia"s Central Committee. But still he had not yet really been noticed.It was Kosovo that gave him his chance. An autonomous province of Serbia, Kosovo was home to an Albanian majority and a Serbian minority. In 1989, he was sent there to calm fears of Serbians who felt they were discriminated against. But instead he played the nationalist card and became their champion. In so doing, he changed into a ruthless (无情的) and determined man. At home with Mira he plotted the downfall of his political enemies. Conspiring (密谋) with the director of Serbian T. V., he mounted a modern media campaign which aimed to get him the most power in the country.He was elected Serbian president in 1990. In 1997, he became president of Yugoslavia. The rest of the story is well-known: his nationalist card caused Yugoslavia"s other ethnic groups to fight for their own rights, power and lands. Yugoslavia broke up when four of the six republics declared independence in 1991. War started and lasted for years and millions died. Then Western countries intervened. N.A.T.O. bombed Yugoslavia, and he eventually stepped down as state leader in 2000.Soon after this, Serbia"s new government, led by Zoran Djindjic, arrested him and sent him to face justice at the Yugoslav war crimes tribunal in the Hague. Why was Milosevic sent to Kosovo in 1989
Robotic Highway ConesA University of Nebraska professor has developed robotic cones and barrels. 1 They can even be programmed to move on their own at any particular part of the day, said Shane Farritor, an assistant professor of mechanical engineering at Nebraska.For example, if workers arrived at 6 a. m., the cones could move from the side of the highway to block off the lane at that time. 2 "It just seems like a very good application for robots," Farritor said. "The robotic cones would also help remove people from hazardous jobs on the highway putting barrels and cones into place," Farritor said in a report on his creation. 3 The fund allowed Farritor to work on the project with graduate students at Nebraska and his assistant Steve Goddard.The robots are placed at the bottom of the cones and barrels and are small enough not to greatly change the appearance of the construction aides. "It would look exactly the same," Farritor said. "Normally there"s a kind of rubbery, black base to them. 4 "Farritor has talked with officials from the Nebraska Department of Roads about how the robots would be most useful to what they might need.The robots could come in handy following a slow-moving maintenance operation, like painting a stripe on a road or moving asphalt, where now the barrels have to be picked up and moved as the operation proceeds. "That way you don"t have to block off a 10-mile strip for the operation," Farritor said.While prototypes have been made, they are not in use anywhere. Farritor said he has applied for a patent and is considering what to do next. 5 He is also thinking about marketing the robots to roads departments and others across the country who may benefit from them.A. And they can return to the original place at the end of the day.B. He is thinking about starting a small business.C. Farritor was "Inventor of the Year" in 2003.D. Work on the idea began in 2002 using a National Academy of Sciences grant.E. We replace that with a robot.F. These robotic cones and barrels can move out of the way, or into place, from computer commands made miles away.
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