Scientists at Rensselaer Polytechnic Institute have found a way to grow aluminum nitride crystals large enough to slice into semiconductor substrates. The crystals can be used to make blue and ultraviolet lasers and light-emitting diodes (LEDs). "Semiconductor light sources have always been very attractive because of their ruggedness and economy," says Leo Schowalter, professor of physics at Rensselaer. "But the color of LEDs has been pretty much limited to red. Green and blue LEDs are also needed if we are to create traffic signals, automobile lighting, flat-screen TV sets, and other applications where long life and high efficiency are important." A Rensselaer researcher, Glen Slack, has demonstrated that you can grow aluminum nitride crystals in a tungsten crucible at 2,300C. However, at that temperature, the aluminum attacks the grain boundaries in the tungsten, and the crucible doesn't survive very long. Schowalter and Slack have now solved the problem and formed a company to make the aluminum nitride crystals. E-mail email@example.com.
The Dutch are known for their love of bicycling, and they’ve also long been early adopters of green-energy and smart-city technologies. So it seems fitting that a town in which painter Vincent van Gogh once lived has given him a very Dutch-like tribute -- a bike path lit by a special smart paint in the style of the artist's “Starry Night” painting.
For decades, engineers have worked to combat erosion by developing high-strength alloys, composites, and surface coatings. However, in a new paper, a team at Jilin University in China turned to one of the most deadly animals in the world for inspiration -- the yellow fat-backed scorpion.
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