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第313行： − 考虑到恒星，爱德华·亚瑟·米尔恩给出了局部热力学平衡的定义，即每个局部细胞中物质的热辐射。他定义了细胞中的局部热力学平衡，要求它在宏观上吸收和自发放射辐射，就好像它处于细胞物质温度的辐射平衡中一样。然后严格遵守基尔霍夫辐射发射率和吸收率相等的定律，使用一个黑体源函数。这里局域热力学平衡的关键在于，可重物质粒子的碰撞速率，比如分子，应该远远超过光子的产生和湮灭速率。+
→Milne's definition in terms of radiative equilibrium
Edward A. Milne, thinking about stars, gave a definition of 'local thermodynamic equilibrium' in terms of the thermal radiation of the matter in each small local 'cell'. He defined 'local thermodynamic equilibrium' in a 'cell' by requiring that it macroscopically absorb and spontaneously emit radiation as if it were in radiative equilibrium in a cavity at the temperature of the matter of the 'cell'. Then it strictly obeys Kirchhoff's law of equality of radiative emissivity and absorptivity, with a black body source function. The key to local thermodynamic equilibrium here is that the rate of collisions of ponderable matter particles such as molecules should far exceed the rates of creation and annihilation of photons.
Edward A. Milne, thinking about stars, gave a definition of 'local thermodynamic equilibrium' in terms of the thermal radiation of the matter in each small local 'cell'. He defined 'local thermodynamic equilibrium' in a 'cell' by requiring that it macroscopically absorb and spontaneously emit radiation as if it were in radiative equilibrium in a cavity at the temperature of the matter of the 'cell'. Then it strictly obeys Kirchhoff's law of equality of radiative emissivity and absorptivity, with a black body source function. The key to local thermodynamic equilibrium here is that the rate of collisions of ponderable matter particles such as molecules should far exceed the rates of creation and annihilation of photons.
考虑到恒星，爱德华·亚瑟·米尔恩根据每个小局部“单元”中物质的热辐射，给出了局部热力学平衡的定义。他定义一个“单元”中的局部热力学平衡，要求它在宏观上吸收和自发放射辐射时，就好像它处于该“单元”中物质温度的辐射平衡中一样。然后使用一个黑体源函数，严格遵守基尔霍夫辐射发射率和吸收率相等的定律。这里局部热力学平衡的关键在于，像分子这样的有重量物质粒子的碰撞速率，应该远远超过光子的产生和湮灭速率。
==Entropy in evolving systems==
==Entropy in evolving systems==