1.6 The Closed System S.J.T.U. Phase Transformation and Applications 1st Law:for a closed system Conservation of energy &Q+δw=dU Nuclear reaction? Q and W are not state functions U is a point or state function 8O+W=dU+d(PE)+d(KE) PE:potential energy KE:kinetic energy Usefulness:one of the terms is unknown SJTU Thermodynamics of Materials Spring2010©X.J.Jin Lecture 1 First law I 22/38Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 1 First law I 22/38 1.6 The Closed System 1 st Law: for a closed system QW  d U Q and W are not state functions U is a point or state function QW  d U  d(PE)  d(KE) PE: potential energy KE: kinetic energy Usefulness: one of the terms is unknown Conservation of energy Nuclear reaction?