改进工艺 制作“完美的玻璃”
文章来源:未知 文章作者:enread 发布时间:2011-06-17 05:39 字体: [ ]  进入论坛
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Glasses differ from crystals. Crystals are organized in repeating patterns that extend in every direction. Glasses lack this strict organization, but do sometimes demonstrate order among neighboring atoms. New research from Carnegie's Geophysical Laboratory reveals the possibility of creating a metallic1 glass(金属玻璃) that is organized on a larger scale. Their results are published June 17 in Science. Scientists have discovered glasses that demonstrate order among the nearest neighboring atoms, called short-range order, and a slightly wider range of atoms, called medium-range order. Most research about finding or creating a glass with a long-range, nearly crystalline, level of order—referred to as the perfect glass state—has been conducted on ice and the minerals silica(二氧化硅) and zeolite(沸石) . But no research into long-range order glass has been successful until now.

The research team, including Carnegie's Ho-Kwang (Dave) Mao, focused on metallic glass made from the elements cerium and aluminum2. Metallic glasses are a hot research topic, because they are less b than ordinary glasses and more resilient than conventional metals. They combine the advantages and avoid many of the problems of normal metals and glasses, two classes of materials with a very wide range of potential applications.

By placing the cerium-aluminum glass under 25 gigapascals of pressure--about 250,000 times normal atmospheric3 pressure--the team was able to create a single crystal. When the glass was brought back to ambient pressure(环境压力) , the new structural4 order was preserved.

Using x-ray techniques and simulations, the team determined5 that the atomic structures of cerium and aluminum prevent the glass from assuming the highly ordered state at normal pressures. But under the intense 25 gigapascals, an electron in cerium shifts, allowing the crystalline structure to be created.

"These exciting results demonstrate that pressurized cerium-aluminum glass could be a favorable system for discovering the long-sought-after perfect glass," Mao said. "This situation could also exist in other metallic glasses."



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1 metallic LCuxO     
adj.金属的;金属制的;含金属的;产金属的;像金属的
参考例句:
  • A sharp metallic note coming from the outside frightened me.外面传来尖锐铿锵的声音吓了我一跳。
  • He picked up a metallic ring last night.昨夜他捡了一个金属戒指。
2 aluminum 9xhzP     
n.(aluminium)铝
参考例句:
  • The aluminum sheets cannot be too much thicker than 0.04 inches.铝板厚度不能超过0.04英寸。
  • During the launch phase,it would ride in a protective aluminum shell.在发射阶段,它盛在一只保护的铝壳里。
3 atmospheric 6eayR     
adj.大气的,空气的;大气层的;大气所引起的
参考例句:
  • Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
  • Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。
4 structural itXw5     
adj.构造的,组织的,建筑(用)的
参考例句:
  • The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
  • The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。
5 determined duszmP     
adj.坚定的;有决心的
参考例句:
  • I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
  • He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。
TAG标签: glass crystal metallic
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