1.4 Energy as a State Function S.J.T.U. Phase Transformation and Applications Equilibrium state and not depend on the thermodynamic path Determined by the parameters that specify the system in its final state and in its initial state. a Equilibrium:its temperature, b pressure,density,and other c physical properties are uniform throughout. qU=U,-U Steady:the system does not change with time. SJTU Thermodynamics of Materials Spring2010©X.J.Jin Lecture 1 First law I 20/38Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 1 First law I 20/38 1.4 Energy as a State Function Equilibrium state and not depend on the thermodynamic path Determined by the parameters that specify the system in its final state and in its initial state. 1 2 a b c U U2 U1 Equilibrium: its temperature, pressure, density, and other physical properties are uniform throughout. Steady: the system does not change with time