Lu Hoff (1914—1997) devoted all his life to scientific research and educational work, and got remarkable results especially for the world famous “Hoff Lu s equation of irreversibility”.

Historical debates on irreversibility in statistical physics;

The Irreversibility in Earth Science-One of Chaotic Characteristics;

Irreversibility and Regional Sustainable Development;

In terms of the symmetry of the physical variable describing the thermodynamic system, the concept and the characters of entropy is introduced with the analogy method,and the principle of entropy increment has been established based on the relationship between the work and the energy in the reversible process in contrast with the irreversible process.

In this paper，We discuss the realizability about the design for reversible processduring which we calculate entrop variation in irreversible process and the arbitrariness，con－vence base on it

In this paper, the production and numerical value relation of energy degeneration in thermodynamical system were studied by analysing quantitatively two typical irreversible processes.