Surface modification of silicone rubber by CF4 radio frequency capacitively coupled plasma for improvement of flashover

The flashover performance of insulating materials plays an important role in the development of high-voltage insulation systems. In this paper, silicone rubber(SIR) is modified by CF₄ radio frequency capacitively coupled plasma (CCP) for the improvement of surface insulation performance. The discharge mode and active particles of CCP are diagnosed by the digital single-lens reflex and the spectrometer. Scanning electron microscopy and x-ray photoelectron spectroscopy are used for the surface physicochemical properties of samples, while the surface charge dissipation, charge accumulation measurement, and flashover test are applied for the surface electrical characteristics. Experimental results show that the fluorocarbon groups can be grafted and the surface roughness increases after plasma treatment. Besides, the surface charge dissipation is decelerated and the positive charge accumulation is inhibited obviously for the treated samples. Furthermore, the surface flashover voltage can be increased by 26.67% after 10 min of treatment. It is considered that strong electron affinity of C–F and increased surface roughness can contribute to deepening surface traps, which not only inhibits the development of secondary electron emission avalanche but also alleviates the surface charge accumulation and finally improves the surface flashover voltage of SIR.     

钻井管具常见问题的原因及预防

介绍了钻具的井工作状况,分析了钻井具失效的原因,提出了避免钻具损坏的措施,旨在减少钻井作业故障,提高钻井作业的效率,节省作业成本,提高经济效益。     

Development of an atmospheric fluorocarbon plasma jet generated by pulse modulated microwave discharge

Atmospheric fluorocarbon plasma plays an important role in the surface modification of insulating materials like polymers. The existing fluorocarbon plasma is usually generated by dielectric barrier discharge, which has a low concentration of reactive species and may cause insufficient surface fluorination. This work attempts to develop an atmospheric fluorocarbon plasma jet using a coaxial transmission line resonator by microwave discharge with locally enhanced electric field and high density. ...     

Effect of Cold Plasma on Cell Viability and Collagen Synthesis in Cultured Murine Fibroblasts

An argon atmospheric pressure plasma jet was employed to treat L929 murine fibroblasts cultured in vitro.Experimental results showed that,compared with the control cells,the treatment of fibroblasts with 15 s of plasma led to a significant increase of cell viability and collagen synthesis,while the treatment of 25 s plasma resulted in a remarkable decrease.Exploration of related mechanisms suggested that cold plasma could up-regulate Cyclin D1 gene expression and down-regulate p27 gene expression at a low dose,while it could down-regulate Cyclin D1 expression and up-regulate p27 expression at a higher dose,thus altering the cell cycle progression,and then affecting cell viability and collagen synthesis of fibroblasts.