2.基本热力学函数的确定 内能同U=7S-pd aS aS S=S(T,V),ds dT+ dE aT aS O aS aS aT U=U(, V), du p dy du dt+ aT aU dT+ aT S aU aT aT aT dU=CpdT+ )叫 ds= dr op dv T aT2. 基本热力学函数的确定 内能 dU = TdS − pdV V V U T T U U U T V U V T ( , ), d d  d         +        = = V V S T T S S S T V S V T ( , ), d d  d         +        = = p V V S T T T S U T V T d d d       −         +        = T T V p V S          =        V V V T S T T U C          =        = p T p T V U T V  −         =        p V T p U C T T V d V d d       −        = + V T p T T C S V V d d  d        = +