上海交通大学：《材料热力学 Thermodynamics of materials》课程教学资源（课件讲稿）lecture 2 第一定律 First law（2/2）

Internal energy is only a function of temperature S.J.T.0. Phase Transformation and Applications 温度计 Experiment Joule 1843 低压 9+0-0 气体 真空 水浴 Imply... 简单体系（例子：封闭气体）只需由两个变量确定 低压气体的内能仅仅是温度的函数 SJTU Thermodynamics of Materials Spring2008©X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 2 First Law II Internal energy is only a function of temperature Experiment Joule 1843 Q W  dU 简单体系（例子：封闭气体）只需由两个变量确定 低压气体的内能仅仅是温度的函数 Imply…

1.15 Equations of State(2) S.J.T.0. Phase Transformation and Applications Ideal gas its internal energy does not change with volume at constant temperature. H=U+PV =0 ap ap +V =? 〔〔+ aH =0-V+V=0 OH ap 3H =0 av aP SJTU Thermodynamics of Materials Spring 2008 X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 2 First Law II 1.15 Equations of State (2) Ideal gas : its internal energy does not change with volume at constant temperature.   0   V T U   ?   P T H V P V P P U P H T T T                H U  PV V P RT P P V V U P H T T T                  2   0    0    V V PH T   ?   V T H   0   P T H

1.15 Equations of State(3) S.J.T.0. Phase Transformation and Applications Joule-Thomson coefficient for an ideal gas aP = 工=0 =0 H Euler 02 ay SJTU Thermodynamics of Materials Spring 2008 X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 2 First Law II 1.15 Equations of State (3) Joule-Thomson coefficient for an ideal gas.   0   P T H  0              PT H JT THPH PT  x y z y z x z x y             Euler

1.15 Equations of State (4) S.J.T.0. Phase Transformation and Applications Difference in heat capacities of an ideal gas 〔-〔器+) H=U+PY c,-G-[2器 SJTU Thermodynamics of Materials Spring2008©X.J.Jin Lecture 2 First Law ll

Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 2 First Law II 1.15 Equations of State (4) Difference in heat capacities of an ideal gas. P V P V T U T H C C           H U  PV P P T P V P T U T H              P P V P V T U T V P T U C C               