Propylene carbonate （PC） has a great potential to be used as an energy storage medium in the compact pulsed power sources due to its high dielectric constant and large resistivity. We investigate both the positive a...Propylene carbonate （PC） has a great potential to be used as an energy storage medium in the compact pulsed power sources due to its high dielectric constant and large resistivity. We investigate both the positive and negative breakdown characteristics of PC. The streamer patterns are obtained by ultra-high-speed cameras. The experimental results show that the positive breakdown voltage of PC is about 135% higher than the negative one, which is abnormal compared with the common liquid. The shape of the positive streamer is filamentary and branchy, while the negative streamer is tree-like and less branched. According to these experimental results, a charge layer structure model at the interface between the metal electrode and liquid is presented. It is suggested that the abnormal polarity effect basically arises from the electric field strength difference in the interface between both electrodes and PC. What is more, the recombination radiation and photoionization also play an important role in the whole discharge process.展开更多
Based on analyzing the circulation development of 100 hPa, 500 hPa, lower streamline field and the change of physical vadables, the diagnostic analysis of a turning cold wave process in northern Xinjiang from Feb. 10 ...Based on analyzing the circulation development of 100 hPa, 500 hPa, lower streamline field and the change of physical vadables, the diagnostic analysis of a turning cold wave process in northern Xinjiang from Feb. 10 -13th 2009 was carried out. The results showed that abnormality of 100 hPa polar vortex taking on stable two waves, catastrophe of 500 hPa western Siberian trough, strong cold advection and water vapor transport from Middle Asia are chief reasons of the process.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 51677190the Hunan Provincial Natural Science Foundation of China under Grant No 2017JJ1005
文摘Propylene carbonate （PC） has a great potential to be used as an energy storage medium in the compact pulsed power sources due to its high dielectric constant and large resistivity. We investigate both the positive and negative breakdown characteristics of PC. The streamer patterns are obtained by ultra-high-speed cameras. The experimental results show that the positive breakdown voltage of PC is about 135% higher than the negative one, which is abnormal compared with the common liquid. The shape of the positive streamer is filamentary and branchy, while the negative streamer is tree-like and less branched. According to these experimental results, a charge layer structure model at the interface between the metal electrode and liquid is presented. It is suggested that the abnormal polarity effect basically arises from the electric field strength difference in the interface between both electrodes and PC. What is more, the recombination radiation and photoionization also play an important role in the whole discharge process.
基金Supported by Forecaster Special Project of New Technique Populanzationof China Meteorological Administration(CMATG2009YB10)~~
文摘Based on analyzing the circulation development of 100 hPa, 500 hPa, lower streamline field and the change of physical vadables, the diagnostic analysis of a turning cold wave process in northern Xinjiang from Feb. 10 -13th 2009 was carried out. The results showed that abnormality of 100 hPa polar vortex taking on stable two waves, catastrophe of 500 hPa western Siberian trough, strong cold advection and water vapor transport from Middle Asia are chief reasons of the process.
