中文摘要：

测量纳米SiQx/低密度聚乙烯（LDPE）复合介质在强场下的电导特性时，发现这种介质具有预电应力效应，即复合介质经相同极性的较高直流电场（8×10^7V／m）预压作用2h后，直流电导比预压前的小，并随着纳米SiQx浓度的增加，这种预电应力效应越明显。通过透射电子显微镜（TEM）研究了纳米SiQx与LDPE之间的界面状态及纳米SiQx在LDPE中的分散形态；X射线衍射（XRD）结果表明纳米SiQx影响LDPE的结晶形态；另外运用傅立叶红外光谱（FTIR）研究了纳米SiQx与LDPE分子链间的相互作用。文章最后结合上述微观测试结果解释了纳米SiQx的添加所引起的LDPE强场下的预电应力效应。

英文摘要：

The effect of electrically pre-stressing in the composite of nano-SiOx / low-density polyethylene （LDPE） was found during measuring the high-electrical-field conduction of the composite. It means that the direct current （DC） conduction of the composite after being electrically pre-stressed with the same polarity high DC electrical stress （about 8×10^7 V/m） for 2h was lower than that without being pre-stressed. More interesting is that the effect of electrically pre-stressing becomes more obvious with increasing of the content of nano-SiOx. Interfaces between nano-SiOx and LDPE were investigated with transmission electron microscope （TEM）, so did the dispersing status of nano-SiOx in LDPE. The effect of nano-SiOx on crystallinity and crystal morphology of the composite was verified via X-ray diffraction （XRD）. At the same time, the interaction between nano-SiOx and molecular chain of LDPE was studied with Fourier Transform Infrared Spectrum （FUR）. Finally, the mechanism of the effect of electrically pre-stressing in the composite was explained with microscopic measuring results mentioned above.