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排序方式: 共有430条查询结果,搜索用时 140 毫秒
91.
通过引入描述多孔材料中非零压状态基体体积占有比的承压系数αv,取代过去常用的多孔度α,对多孔材料的本构方程进行修正而得到p=αvF(αv, E),解决了多孔材料发生熔化时,本构方程不适用的问题。应用结果表明,这种修正是合理的和可行的,对多孔材料的数值模拟工作具有一定的参考价值。 相似文献
92.
语音交互系统中基于Cyclone FPGA的交换机设计 总被引:1,自引:0,他引:1
以Cyclone FPGA器件为核心,设计数据交换机.描述了Cyclone器件中LVDS接口、锁相环PLL、片内M4KRAM模块、芯片配置的应用方法和技巧,给出了软件设计思路,并研制了数据下栽线.经实际测试和运行,交换机的各项性能指标达到原设计要求,并具有高可靠性和高性价比. 相似文献
93.
Chonung Kim Zhijian Jin Pingkai Jiang Qingquan Ke 《Polymer Degradation and Stability》2007,92(4):537-544
The power cable insulation is in permanence subjected to thermal aging during its operating service. Thermal aging may influence not only the electrical, physicochemical and other properties of the XLPE cable insulation, but also the initiation and propagation of water tree inside it. Our research on the influence of thermal degradation to the water treeing behavior of XLPE cable insulation shows that thermal oxidation is the most influential to the initiation and growth of water treeing from the surface of XLPE cable insulation among all the probable factors caused during thermal aging. 相似文献
94.
Investigations of the pyrolysis of poly(vinyl chloride) (PVC) in the presence of copper metal (Cu), copper(II) oxide (CuO) and copper(II) chloride (CuCl2) are of potential importance because of the likelihood of the formation of these copper compounds during the thermal degradation of PVC-coated copper wires, a step in the recovery of copper from waste. The presence of Cu, CuO and CuCl2 (i) retards the thermal degradation of PVC in air and in nitrogen and (ii) decreases the percentages of volatile products produced at both stages of the decomposition. These effects are greatest for PVC-CuO. The presence of copper, CuO or CuCl2 in PVC has a major effect on the nature of the gaseous emissions of the thermal decomposition in air and in nitrogen. The concentrations of total chlorine, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons and soot particulates are all affected relative to an equivalent amount of PVC. These changes are greatest for the PVC-CuO system for which total chlorine emissions in air and nitrogen are reduced by 40% in air and 20% in nitrogen, benzene emissions are reduced by greater than 90% in air and nitrogen, other aromatic and chloroaromatic emissions are reduced, and soot particulate emissions are reduced by more than 50% as the concentrations of aliphatic compounds are increased. These changes are consistent with the presence of copper or its compounds permitting more efficient combustion of the carbon content of the PVC and particularly in the case of PVC-CuO with the removal of chlorine during pyrolysis in the inorganic phase. 相似文献
95.
Several electrical approaches were used to monitor the electrical degradation of ethylene propylene rubber (EPR) cable under (1) high temperature water submerged for long-term, (2) room temperature water submerged after thermal and radiation aging, and (3) loss-of-coolant accident simulation conditions. The moisture-related degradation behavior was investigated by the correlation of electrical measurements, moisture content analysis, and scanning electron microscope (SEM) observation. The results indicate that void size and density of insulation material strongly affect the material's water resistant capability and electrical degradation. Also, the void size of insulation material after moisture-related degradation is much bigger than that after thermal and radiation aging, and the former causes material swelling. Combining insulation resistance and dissipation factor condition monitoring (CM) techniques can provide useful means for monitoring cable degradation while the cable is exposed to moisture and high temperature/radiation environment. The Arrhenius model is applied together with appropriate acceptance criteria obtained by insulation resistance measurement to calculate cable remaining life. According to test results and the remaining life calculation, it is shown that the moisture-related degradation of EPR cable can be early assessed by insulation resistance measurement, which is a non-destructive prognostic CM technique. 相似文献
96.
静电纺丝技术制备TiO2@SiO2亚微米同轴电缆与表征 总被引:2,自引:0,他引:2
用静电纺丝技术成功制备出大量的TiO2@SiO2亚微米同轴电缆. 用TGA-DTA, XRD, SEM, TEM, EDS, FTIR分析技术对样品结构和组成进行了系统的表征. 结果表明, 得到的产物为TiO2@SiO2亚微米级同轴电缆, 以无定型SiO2为壳层, 晶态TiO2为芯层, 电缆平均直径450 nm, 壳层厚度90 nm, 电缆长度>300 μm, 同时在样品中发现个别纤维呈现管状结构, 对其形成机理进行了讨论. 相似文献
97.
A. Wutzler H.-J. Radusch K. Gehrmann 《Journal of Macromolecular Science: Physics》2013,52(5-6):1095-1099
The diffusion of acetophenone in peroxide cross-linked low-density polyethylene (LDPE) medium-voltage cable was investigated with Fourier transform infrared (FTIR) microscopy. The influence of storage under normal climate and for up to 2 years on the acetophenone profile are discussed. The diffusion rate and the coefficient of diffusion of acetophenone in cross-linked LDPE were determined. It could be shown that the coefficient of diffusion is independent of the morphology of the medium-voltage cables investigated. 相似文献
98.
99.
针对兆伏安级容量的超导变压器,通过绕组初步设计,考虑导体的电流密度、载流量和交流损耗,提出面向大容量超导变压器应用的新型超导复合导体结构,介绍了含内外超导层的新型高温超导复合导体的结构。引入电流矢量T和磁矢量势A的方法,考虑临界电流密度J_c和磁场B的关系,建立了导体不对称三维数值载流模型,计算分析了不同结构参数对导体临界电流的影响规律。通过绕制的新型高温超导复合导体短样,在液氮环境下对其自场临界电流进行了测量,计算结果和实验结果基本吻合,验证了模型的合理性。 相似文献
100.