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EPON用单纤三向模块的设计
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作者 沈开贵 《光通信技术》 CSCD 北大核心 2007年第5期44-46,共3页
目前人们更为关注的EPON与GPON,它们都具有同时传输TDM、IP数据和视频广播的能力。对于视频广播,是通过扩展第三波长(1550nm)来实现的,称为RF overlay。文章介绍了RF overlay EPON系统对用户端单纤三向模块的性能要求,并分析了三向模块... 目前人们更为关注的EPON与GPON,它们都具有同时传输TDM、IP数据和视频广播的能力。对于视频广播,是通过扩展第三波长(1550nm)来实现的,称为RF overlay。文章介绍了RF overlay EPON系统对用户端单纤三向模块的性能要求,并分析了三向模块的基本原理以及设计中的要点。最后给出了样品的测试结果,结果表明该样品满足IEEE802.3ah建议要求,可以应用在EPON系统中。 展开更多
关键词 RF OVER LAY 三向模块 突发发射
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Stability analysis for main roof of roadway driving along next goaf 被引量:3
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作者 柏建彪 《Journal of Coal Science & Engineering(China)》 2003年第1期22-27,共6页
Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and ... Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth. 展开更多
关键词 roadway driving along next goaf triangle block structure stability analysis
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