上游充通大￥ System at constant energy:Microcanonical ensembles SHANGHAI JIAO TONG UNIVERSITY System at Constant Temperature Canonical ensemble A closed system,with a fixed number of particals N and in a fixed volume V,immersed in a large constant temperature bath. S=-t∑PhP Gibbs formulation P= 2 Gibbs formation identical to the Boltzmann formulation. S=一K Pi The probability that the system will be in microstate i,and the sum s--in gi is the sum over all the micorstate. S=kIn Boltzmann HypothesisSystem at constant energy: Microcanonical ensembles Gibbs formulation Boltzmann Hypothesis