一回顾( Rev iew) 热力学第一定律 (The First Law of Thermodynamics) 能量守恒与转换定律 能量之间数量的关系
热力学第一定律 （The First Law of Thermodynamics) 能量守恒与转换定律 能量之间数量的关系 回顾(Review)
a process must satisfy the first law of Thermodynamics to occur. (一个过程必须满足热力学第一定律才能发生) ◆是否满足能量守恒与转换定律的过程一定都能自动发生? Satisfying the first law alone does not ensure that the process will actually take place. 但是,满足热力学第一定律的过程未必都能发生)
◆ 是否满足能量守恒与转换定律的过程一定都能自动发生? ◆ A process must satisfy the first law of Thermodynamics to occur. (一个过程必须满足热力学第一定律才能发生) ◆ Satisfying the first law alone does not ensure that the process will actually take place. (但是，满足热力学第一定律的过程未必都能发生）
Chapter 5.The Second Law of Thermodynamics (第五章热力学第二定律) 45.1自发过程的方向性) The Direction of Spontaneous Process 45.2热力学第二定律的表述 Statement of the second law of Thermodynamics 5.3卡诺循环与卡诺定律 Carnot cycle and Carnot Theorem 5.4熵、熵增原理及熵方程 Entropy the increase principle of Entropy and Entropy Equation 45.5熵的意义及应用 Significance of Entropy and its application
5.1自发过程的方向性） The Direction of Spontaneous Process 5.2热力学第二定律的表述 Statement of the Second Law of Thermodynamics 5.3卡诺循环与卡诺定律 Carnot cycle and Carnot Theorem 5.4熵、熵增原理及熵方程 Entropy, The increase principle of Entropy and Entropy Equation 5.5熵的意义及应用 Significance of Entropy and its application Chapter 5.The Second Law of Thermodynamics （第五章 热力学第二定律）
5.1 Spontaneous Process(自发过程) 过程的方向性 温差传热( Heat transfer under temperature difference) Qa=QE V A B Q↑TA>Tp,aA-B× QB ●自由膨胀( Free Expansion t=-------------- U1=U2 B U1=U2 温差传热和自由膨胀均为不平衡势差推动下的非准静态过程,也即不可逆过程
过程的方向性 ⚫ 温差传热 (Heat Transfer under temperature difference) ⚫ 自由膨胀 (Free Expansion) A B TA> TB, A B QA QB U1=U2 QA= QB QA= QB U1=U2 √ × √ × §5.1 Spontaneous Process （自发过程） 温差传热和自由膨胀均为不平衡势差推动下的非准静态过程,也即不可逆过程
摩擦生热 U2=U1+mc2/2 U1=U2+mc2/2 电容一电阻电路
⚫ 摩擦生热 ⚫ 电容－电阻电路 U2=U1+mc2/2 U1=U2+mc2/2