2.1 Entropy as a State Function(1) S.J.T.U. Phase Transformation and Applications For a close system the reversible heat flow divided by the absolute temperature of the system is a state or point function. T 可逆过程的热温商！ Entropy S The unit of entropy:joules per kelvin in SI system. Relationship between entropy changes and transfers of heat and irrevisibilities in a macroscopic sense. SJTU Thermodynamics of Materials Spring2010©X.J.Jin Lecture 3 Second law IPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 3 Second law I 2.1 Entropy as a State Function(1) For a close system the reversible heat flow divided by the absolute temperature of the system is a state or point function. Entropy S The unit of entropy: joules per kelvin in SI system. Relationship between entropy changes and transfers of heat and irrevisibilities in a macroscopic sense. dS T Qrev   可逆过程的热温商！