Two new derivatives of 4 - dicyanomethylene - 2,6 - dimethyl - 4H - pyran and the corresponding poly (amic acid) were synthesized and characterized.是什么意思_Two new derivatives of 4 - dicyanomethylene - 2,6 - dimethyl - 4H - pyran and the corresponding poly (amic acid) were synthesized and characterized.在线翻译_英语_读音_用法_例句