NuN=Is Isn=A(GUs-Is) 即: G11G12····C 1 ●●●● GnI grn n n nnn G G G G G G G G G • • • • • • • • • • • • • • • • • • • • • • 1 2 21 22 2 11 12 1 nnnn UUU•• 21 Inn II•• 22 11 = 即： Gn Un = Isn Isn = A (GUS − IS )