d(△A1)k△l dt2√t from 1, 3 D= DANB+ DBNA N A, NB: mole fraction NB-C+CB c+c B △=bt→y= b△l 2√t2t 测l,记录t,可得到ν,由实验曲线计算D, 由D、v,即可求得D4,DB( ) (4) d 2 2 d t l t k t l  = =   = A B A A A B B B C C C N C C C N + = + = from 1,3 (5) D = DA NB + DB NA NA , NB : mole fraction t l t b l b t v 2 2   =  = = 测l，记录t，可得到v，由实验曲线计算D， 由D、v，即可求得DA，DB