【摘要】 低密度聚乙烯在直流电场下的电荷包行为注入的现象已经被多次报导,但其中的原理尚未得到合理的解释.目前针对低密度聚乙烯(LDPE)在直流电场下出现的电荷包行为主要有以下两种观点(1)电极注入的过量电荷在外加电场作用下形成电荷包向另一个电极迁移,在传输过程中电荷包中的电荷不断被材料中的陷阱捕获而逐渐衰减.(2)材料中的杂质分子在局域强场效应作用下离解产生大量载流子,电荷包在移动过程中存在散射与衰减.这两种机制在描述电荷包的行为时都存在一定的困难.作者利用激光压力波法(PWP)对低密度聚乙烯(LDPE)在较低直流电场(约50kV/mm)下的空间电荷包注入现象进行了测量,并尝试从耿氏效应(Gunn)来讨论分析空间电荷包行为.更多还原

【Abstract】 Packet-like space-charge behavior in low-density polyethylene under dc field has been reported frequently. However no reasonable explanation for the space-charge behavior under dc fields has been given out, Now there are two kinds of opinion about the mechanism of charge packet formation under dc fields: (1)The superfluous charge injected by electrode formed the space charge packet and travel from one electrode to another under applied field. In the course of transmission, the charges in the packet would be continually captured by the traps in the materials and the packet would decay gradually.(2)the packet formation is caused by the carriers generated from the dissociation of the impure molecules under the highly enhanced field. These two mechanisms both have some difficulties in explain the space charge packet behavior. In this thesis, PWP (pressure Wave Proqagation) method are utilized to study space charge packet behavior of LDPE(low density Polyethylene).and we try to use Gunn effect to analyse the space charge packet behavior.更多还原