| 结构功能一体化的高性能陶瓷材料的研究与开发 |
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| 作者姓名： | Huang Zhixun Lu Guizhen Guan Jian |
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| 作者单位： | 高性能陶瓷和超微结构国家重点实验室，中国科学院上海硅酸盐研究所，上海 200050 |
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| 摘 要： | 从当前新材料的开发和材料科学发展向多功能、小型化、复合化、低成本制备等要求出发, 并就现有高性能陶瓷材料的基本性能和材料制备工艺上的优缺点进行了分析；简要介绍了碳化硅(SiC)陶瓷、 添加Nd的钇铝石榴子石(Nd-YAG)陶瓷、掺有稀土的氮化硅(RE-Si3N4)陶瓷等几种具有结构和功能一体化高性能陶瓷材料的优良性能,可能的应用以及目前存在的问题,特别是在基础研究和制备科学上今后应予以关注的方面。
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| 关 键 词： | 结构和功能一体化 高性能陶瓷 碳化硅 Nd-YAG RE-Si3N4 |
| 收稿时间： | 7/8/2002 12:00:00 AM |
Superluminal and Negative Group Velocity in the Electromagnetic Wave Propagation |
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| Huang Zhixun,Lu Guizhen,Guan Jian.Superluminal and Negative Group Velocity in the Electromagnetic Wave Propagation[J].Engineering Sciences,2003,1(2):35-39. |
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| Authors: | Huang Zhixun Lu Guizhen Guan Jian |
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| Institution: | Department of Communication Engineering, Beijing Broadcasting Institute, Beijing 100024 |
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| Abstract: | In this paper, a penetrating analysis is first made of the superluminal and negative group velocities that occur in the EM wave propagation. Discussed then are the superluminal and negative group velocities which are in the state of evanescent waves in the waveguide below cutoff(WBCO).Through an experiment in the coaxial photonic crystal a group velocity of 1.5-2.4 times the speed of light are observed in the stop band |
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