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→Ponderable matter 疑难杂症
=== Ponderable matter 疑难杂症===
=== Ponderable matter 物质的可估量性===
''Local thermodynamic equilibrium of matter''<ref name="Gyarmati 1970"/><ref name="G&P 1971"/><ref name="Balescu 1975"/><ref name="Mihalas Mihalas 1984"/><ref name="Schloegl 1989"/> (see also Keizer (1987)<ref name="Keizer 1987"/> means that conceptually, for study and analysis, the system can be spatially and temporally divided into 'cells' or 'micro-phases' of small (infinitesimal) size, in which classical thermodynamical equilibrium conditions for matter are fulfilled to good approximation. These conditions are unfulfilled, for example, in very rarefied gases, in which molecular collisions are infrequent; and in the boundary layers of a star, where radiation is passing energy to space; and for interacting fermions at very low temperature, where dissipative processes become ineffective. When these 'cells' are defined, one admits that matter and energy may pass freely between contiguous 'cells', slowly enough to leave the 'cells' in their respective individual local thermodynamic equilibria with respect to intensive variables.
''Local thermodynamic equilibrium of matter''<ref name="Gyarmati 1970"/><ref name="G&P 1971"/><ref name="Balescu 1975"/><ref name="Mihalas Mihalas 1984"/><ref name="Schloegl 1989"/> (see also Keizer (1987)<ref name="Keizer 1987"/> means that conceptually, for study and analysis, the system can be spatially and temporally divided into 'cells' or 'micro-phases' of small (infinitesimal) size, in which classical thermodynamical equilibrium conditions for matter are fulfilled to good approximation. These conditions are unfulfilled, for example, in very rarefied gases, in which molecular collisions are infrequent; and in the boundary layers of a star, where radiation is passing energy to space; and for interacting fermions at very low temperature, where dissipative processes become ineffective. When these 'cells' are defined, one admits that matter and energy may pass freely between contiguous 'cells', slowly enough to leave the 'cells' in their respective individual local thermodynamic equilibria with respect to intensive variables.
在这里，人们可以想到两个“弛豫时间”之间的数量级分隔。较长的弛豫时间约为系统宏观动力学结构发生变化所需的时间量级。较短的是独立“单元”达到局部热力学平衡所需的时间量级。如果这两个驰豫时间没有很好地分开，那么局部热力学平衡的经典非平衡热力学概念就失去了意义，那么必须提出其他方法，例如扩展的不可逆热力学。例如，在大气中，音速远大于风速；这有利于物质的局部热力学平衡的想法，对于在低于60 km的高空进行大气传热研究，声音可以在其中传播，但需要限制在100 km以内，因为分子间碰撞发生的很少，因此声音无法传播。
在这里，人们可以想到两个“弛豫时间”之间的数量级分隔。较长的弛豫时间约为系统宏观动力学结构发生变化所需的时间量级。较短的是独立“单元”达到局部热力学平衡所需的时间量级。如果这两个驰豫时间没有很好地分开，那么局部热力学平衡的经典非平衡热力学概念就失去了意义，那么必须提出其他方法，例如扩展的不可逆热力学。例如，在大气中，音速远大于风速；这有利于物质的局部热力学平衡的想法，对于在低于60 km的高空进行大气传热研究，声音可以在其中传播，但需要限制在100 km以内，因为分子间碰撞发生的很少，因此声音无法传播。
=== Milne's definition in terms of radiative equilibrium 米尔恩Milne在辐射平衡系统方面的定义===
=== Milne's definition in terms of radiative equilibrium 米尔恩Milne在辐射平衡系统方面的定义===