关键词: 绿洲系统, 演化趋势, 非线性热力学, 定态, 负熵流

Abstract: In this paper,based on the second thermodynamics law,the process of entropy change of an open thermodynamic system is analyzed and the thermodynamic direction criterion of thermodynamic system to develop is given out.The thermodynamic direction criterion shows that a thermodynamic system may maintain its state in non-equilibrium and organized structure only while there is negative entropy current from outer environment into the thermodynamic system,otherwise it becomes an equilibrium and unorganized state.From this,an oasis system can be closely treated as a typical open natural thermodynamic system in stationary state.The contributions of inner and outer factors of an oasis system to entropy change are analyzed after the equations of the entropy change caused by energy and matter current from its outer environment are given out.The essence of oasis evolution and the inner and outer conditions to maintain a stable oasis system are discussed.Finally,a simple numerical analysis is presented.

Key words: oasis system, tendency of degeneration, nonlinear thermodynamics, stationary state, entropy current