热机 S.J.T.0. Phase Transformation and Applications A D D B B We need a way to reduce the pressure of the gas inside the cylinder,so that during the compression stage less work has to be done to drive the piston back in.adiabatically The essential step in the carnot cycle is to break the thermal contact with the hot reservoir before the piston is fully withdrawn,at B SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 4 Second law llPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 4 Second law II 热机 We need a way to reduce the pressure of the gas inside the cylinder, so that during the compression stage less work has to be done to drive the piston back in. adiabatically The essential step in the carnot cycle is to break the thermal contact with the hot reservoir before the piston is fully withdrawn, at B