Internal energy is only a function of temperature S.J.T.U. Phase Transformation and Applications 温度计 Experiment Joule 1843 低压 四+0-0 气体 真空 A 水浴 简单体系（例子：封闭气体）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 Spring2006©X.J.Jin Lecture 2 First Law llPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2006 © X. J. Jin Lecture 2 First Law II Internal energy is only a function of temperature Experiment Joule 1843 δ +δ = UdWQ 简单体系（例子：封闭气体）需由两个变量确定 低压气体的内能仅仅是温度的函数