(1)等温可逆膨胀 U=f(T), △U=0 Q=-W=nRT In(V2/V)=nRT In(P/P2) (2)绝热可逆膨胀 Q=0 W2=AU2=-JnCym dT (3)等温可逆压缩 Q3=-W3=nRT2In(V/V3)=nRT2In(P3/Pa) (4)绝热可逆压缩 Q=0 Wa=AU=-JnCvm dT 3 (1) 等温可逆膨胀 U = f(T) ， U = 0 Q1 = -W1 = nRT1 ln(V2 /V1 ) = nRT1 ln(P1 /P2 ) (2) 绝热可逆膨胀 Q= 0 W2= U2 = -∫nCV,m dT (3) 等温可逆压缩 Q3 = -W3 = nRT2 ln(V4 /V3 ) = nRT2 ln(P3 /P4 ) (4) 绝热可逆压缩 Q= 0 W4= U4= -∫nCV,m dT