LEDs produce light when incoming negatively charged electrons and positively charged "holes" attract each other and combine. The electrons and holes have a physical property called "spin" that rotates like the Earth rotating on its axis, but unlike the Earth they can spin in different directions. Physicists once believed that only 25% of the energy flowing into an LED could be emitted as light. Valy Vardeny, the physics chairman at the University of Utah, developed a test that indicates that 41 to 63% of the energy flowing into an LED can be converted to light using plastic LEDs made from organic materials called electrically conducting polymers and oligomers. Vardeny bombarded ten different plastics with microwaves, and found that materials that emit red and blue violet light emitted more light when placed in a magnetic field at cold temperatures. "The findings mean it should be possible to make more efficient light emitters for lasers, displays, and computer and television screens," says Vardeny. For more information, contact the University of Utah, Salt Lake City, UT 84112-9017; FAX: (801) 585-3350.
More often than not, with the purchase of a sports car comes the sacrifice of any sort of utility. In other words, you can forget about a large trunk, extra seats for the kids, and more importantly driving in snowy (or inclement) weather. But what if there was a vehicle that offered the best of both worlds; great handling and practicality?
Science fiction author Isaac Asimov may have the best rules for effective brainstorming and creativity. His never-before-published essay, "On Creativity," recently made it to the Web pages of MIT Technology Review.
Much has been made over the potentially dangerous flammability of lithium-ion batteries after major companies like Boeing, Sony, and Tesla have grappled with well-publicized battery fires. Researchers at Stanford University may have come up with a solution to this problem with a smart sensor for lithium-ion batteries that provides a warning if the battery is about to overheat or catch fire.
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