There are wide variations caused by different academic programme structures.不同的教学项目结构造成了巨大的差异。regional variations in pronunciation发音的地区差异The dial records very slight variations in pressure.该刻度盘能显示很微小的压力变化。...
Hexamethylene diisocyanate ( HMDI ) may be used in prepolymer, in place of TDI.六亚甲基二异氰酸酯 ( HMDI ) 可用在预聚物中代替甲苯二异氰酸酯〔TDI〕.Polyurethane elastomers based on glycols ( PEA, PPG PTMG ) , diisocyanate ( TDI ) and chain extender...