(火积)的微观表述

在近独立粒子组成的系统中,Boltzmann发现了系统熵与其微观状态数的对数之间的正比关系,为熵这一物理概念提供了微观解释,Planck将其总结为著名的Boltzmann熵公式S = k lnΩ.与此对应,给出了单原子理想气体系统中(火积)的微观表达式,证明了(火积)为广延量. 分析讨论了孤立系统从不平衡态发展到热平衡态过程中系统微观状态数、熵、(火积)的变化情况,结果表明在该过程中系统的微观状态数、熵向着增加方向发展,而(火积)则向着减小方向发展,从而在微观角度 关键词： 微观状态数 熵 (火积) 不可逆性

Microscopic expression of entransy

Boltzmann found that a proportional relation exists between the entropy and the logarithm of the microstate number in an approximate non-interaction particle system. The relation was expressed as the Boltzmanns entropic equation by Planck later. Boltzmanns work gives a microphysical interpretation of entropy. In this paper, a microscopic expression of entransy is introduced for an ideal gas system of monatomic molecules. The changes of the microstate number, the entropy and the entransy of the system are analyzed and discussed for an isolated ideal gas system of monatomic molecules going through the initial stage of unequilibriun thermal state to the thermal equilibrium state. It is found that the microstate number and the entropy always increase in the process, while the entransy decreases. The microstate number is a basic physical quantity which could measure the disorder degree of the system. The irreversibility of a thermal equilibrium process is attributed to the increase in microstate number. Entropy and entransy both are single value functions of the microstate number and they both could reflect the change of the state for the system. Therefore, both entropy and entransy could describe the irreversibility of thermal processes.