2.焓H=U+p dh=Tds+vd H=H(S, P),dHa aH ds+ T=/OH aH T(S, P), v V(S, p) a OH aT as aSap aS2. 焓 dH = TdS +Vdp p p H S S H H H S p H p S ( , ), d d d            +        = = ( , ), V(S, p) p H T S p V S H T p S =            = =        = S p H p S H    =    2 2 H =U + pV S S p V p T         =          