NyA=N 总体流动中物质B向右传递的通量为 Nvp=N-B B N=+na No=J+w N=O Ja=NB即JA=N B 2021/2/21 上页返回2021/2/21 C c Ny N A A = 总体流动中物质B向右传递的通量为 C c Ny N B B = C c N J N A  A = A + C c N J N B B = B + 而 NB = 0 C c J N B − B = C c J N B 即 A =