12 ① 22 N2 +12 22 ap,_miz dt dy12=ni dt di M 12 112 dt d 22 d 2 di 22 2 N dt 2 dt dt 可以证明:M12=M21=M。+ u12 – + u22 – i2  12  22 N1 N2 ( ) d d d d d d ( ) d d d d d d 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 2 1 2 2 1 2 1 2 1 1 2 1 2 i Ψ L t i L t Φ N t Ψ u i Ψ M t i M t Φ N t Ψ u = = = = = = = = 可以证明：M12= M21= M