实验结果说明，拉伸前后的这类共聚物薄膜均是极性材料，即充电极化后的材料内部同时存在取向偶极子和俘获空间电荷。
Experimental results point out that the said copolymer electret film is a polar material, i. e. there exist both oriented dipoles and deposited space charges in the film after charging.
分析了橡胶在二甲醚中溶胀的化学机理，并选出具有不同极性的橡胶材料进行耐二甲醚溶胀及溶胀前后拉断强度、拉断伸长率、硬度等力学性能的对比试验。
Chemical mechanism of rubber expansion in DME was analysed, and different rubber materials were selected to test the expansion, the tensile strength, the elongation at break, and the hardness.
分析了橡胶在二甲醚中溶胀的化学机理，并选出具有不同极性的橡胶材料进行耐二甲醚溶胀及溶胀前后拉断强度、拉断伸长率、硬度等力学性能的对比试验。
Chemical mechanism of rubber expansion in DME was analysed, and different rubber materials were selected to test the expansion, the tensile strength, the elongation at break, and the hardness.
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