In this paper,plasma fluorination is combined with plasma silicon deposition to achieve step gradient modification on an epoxy resin surface.The physicochemical characteristics of samples are investigated and the elec...In this paper,plasma fluorination is combined with plasma silicon deposition to achieve step gradient modification on an epoxy resin surface.The physicochemical characteristics of samples are investigated and the electrical performances measured.The obtained results show that compared with untreated and single treated samples,the samples treated by step gradient modification significantly improve the flashover performance.According to experiment and simulation,the mechanism explanations are summarized as follows.First,it is found that the step gradient conductivity can effectively optimize the electric field distribution of a needle-needle electrode.Then,step gradient modification suppresses the accumulation of surface charge at the triple junction and makes the charge distribution more uniform.Furthermore,it can accelerate the surface dissipation on a high electrical field region and control the dissipation rate on a low electrical field region.All these results can restrain surface discharge and increase the flashover voltage.The step gradient modification method proposed in this paper provides a new idea for improving the surface insulation performance.展开更多
Hierarchically porous ZSM‐5 (SiO2/Al2O3 ≈ 120) containing phosphorus was prepared by a one‐step post‐synthesis treatment involving controlled desilication and phosphorous modification. The hierarchically porous ZS...Hierarchically porous ZSM‐5 (SiO2/Al2O3 ≈ 120) containing phosphorus was prepared by a one‐step post‐synthesis treatment involving controlled desilication and phosphorous modification. The hierarchically porous ZSM‐5 featured high thermal and hydrothermal stability. The obtained ZSM‐5zeolites were systematically characterized by X‐ray diffraction, scanning electron microscopy,transmission electron microscopy, N2 adsorption‐desorption, NH3 temperature‐programmed desorption,and 27Al and 31P magic‐angle spinning nuclear magnetic resonance spectroscopy. Theprepared ZSM‐5 displayed enhanced activity and prolonged lifetime toward hydrocarbon cracking.The high activity was attributed to improved coke tolerance owing to the presence of the highlystable mesoporous network of ZSM‐5 and acid sites introduced upon phosphorus modification.Additionally a mechanism of the stabilization of the zeolites by phosphorus was proposed and discussed.展开更多
基金supported by National Natural Science Foundation of China(No.51777076)the Self-topic Fund of State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(No.LAPS2019-21)。
文摘In this paper,plasma fluorination is combined with plasma silicon deposition to achieve step gradient modification on an epoxy resin surface.The physicochemical characteristics of samples are investigated and the electrical performances measured.The obtained results show that compared with untreated and single treated samples,the samples treated by step gradient modification significantly improve the flashover performance.According to experiment and simulation,the mechanism explanations are summarized as follows.First,it is found that the step gradient conductivity can effectively optimize the electric field distribution of a needle-needle electrode.Then,step gradient modification suppresses the accumulation of surface charge at the triple junction and makes the charge distribution more uniform.Furthermore,it can accelerate the surface dissipation on a high electrical field region and control the dissipation rate on a low electrical field region.All these results can restrain surface discharge and increase the flashover voltage.The step gradient modification method proposed in this paper provides a new idea for improving the surface insulation performance.
基金supported by the National Natural Science Foundation of China (21403070, 21573073)National Key Technology Research and De-velopment Program (2012BAE05B02)Shanghai Leading Academic Discipline Project (B409)~~
文摘Hierarchically porous ZSM‐5 (SiO2/Al2O3 ≈ 120) containing phosphorus was prepared by a one‐step post‐synthesis treatment involving controlled desilication and phosphorous modification. The hierarchically porous ZSM‐5 featured high thermal and hydrothermal stability. The obtained ZSM‐5zeolites were systematically characterized by X‐ray diffraction, scanning electron microscopy,transmission electron microscopy, N2 adsorption‐desorption, NH3 temperature‐programmed desorption,and 27Al and 31P magic‐angle spinning nuclear magnetic resonance spectroscopy. Theprepared ZSM‐5 displayed enhanced activity and prolonged lifetime toward hydrocarbon cracking.The high activity was attributed to improved coke tolerance owing to the presence of the highlystable mesoporous network of ZSM‐5 and acid sites introduced upon phosphorus modification.Additionally a mechanism of the stabilization of the zeolites by phosphorus was proposed and discussed.
