为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7......

We report a facile and high-yielding procedure for preparing biphenyltetracarboxylic dianhydrides (BPDAs). This method r......

Polyimides have been widely used in aerospace and microelectronics due to their excellent mechanical properties and ther......