针对我国"三网融合"的不断推进,广电运营商提供数据接入的需求,介绍了在HFC中应用前景广泛的CDOCSIS技术。阐述了C-DOCSIS系统中CMC(Cable media converter)设备的硬件设计思路与方法。经验证此设计方案具有高度的可靠性和稳...针对我国"三网融合"的不断推进,广电运营商提供数据接入的需求,介绍了在HFC中应用前景广泛的CDOCSIS技术。阐述了C-DOCSIS系统中CMC(Cable media converter)设备的硬件设计思路与方法。经验证此设计方案具有高度的可靠性和稳定性,在HFC网络中得到了良好的应用。展开更多
C/C–SiC–HfC composites were fabricated via precursor infiltration and pyrolysis using a mixture solution of organic hafnium-containing polymer and polycarbosilane as precursor. The microstructures and the phases of ...C/C–SiC–HfC composites were fabricated via precursor infiltration and pyrolysis using a mixture solution of organic hafnium-containing polymer and polycarbosilane as precursor. The microstructures and the phases of the composites were analyzed by scanning electron microscopy and X-ray diffraction. The ablation resistance of the composites was evaluated under 3,000 °C oxyacetylene torch. After ablation for 120 s, the composites exhibit good ablation properties with the linear and mass ablation rates of 9.1 9 10-4mm/s and 1.30 9 10-3g/s, which are far lower than those of the C/C–SiC composites. The excellent ablative property of the C/C–SiC–HfC composites is resulted from the formation of HfO2 molten layer on the surface of the composites, which could play a positive role in reducing heat transfer and preventing oxygen transport to the underlying carbon substrate.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51221001 and 51272213)the Author of National Excellent Doctoral Dissertation of China(No.201036),the ‘‘111’’ project of China (No.B08040)National Basic Research program of China (No.2011CB605806)
文摘C/C–SiC–HfC composites were fabricated via precursor infiltration and pyrolysis using a mixture solution of organic hafnium-containing polymer and polycarbosilane as precursor. The microstructures and the phases of the composites were analyzed by scanning electron microscopy and X-ray diffraction. The ablation resistance of the composites was evaluated under 3,000 °C oxyacetylene torch. After ablation for 120 s, the composites exhibit good ablation properties with the linear and mass ablation rates of 9.1 9 10-4mm/s and 1.30 9 10-3g/s, which are far lower than those of the C/C–SiC composites. The excellent ablative property of the C/C–SiC–HfC composites is resulted from the formation of HfO2 molten layer on the surface of the composites, which could play a positive role in reducing heat transfer and preventing oxygen transport to the underlying carbon substrate.
