From the similarity relations of radiative transfer theory,a parameter,namely characteristic length,was introduced on the basis of P_1 and P_3 satisfying approximatly the first-order similarity and third-order similarity relations.

Based on the researching of the infrared decoy countermeasure to the target characteristic length and energy equivalent centre,the countermeasure to the point target image radiation characteristics are analyzed.

By the relationship between the theoretical roughness and fractal parameters,the fractal parameters were introduced into the calculation of trait of a bearing center,and the influences of fractal dimension and characteristic length on the position of bearing center were investigated.

The feature length is to measure the degree in which micro-particle can be described by the model of classical mechanics.

By applying the characteristic theory for hyperbolic equations,we establish an integral system from which ρ(z) and c(z) can be recovered simultaneously.

In detail,gases flows near the boundaries were considered as one-dimensional isoentropic flows,and the characteristic theory of hyperbolic equations was used to analyze the characteristic .

This article elaborated in detail on the application of characteristic theory in three essential parts of language.

It is different from not only irreversible thermodynamics established in the 1930’s but also engineering thermodynamics, and has in itself some distinct theoretical characteristics.

The kernel values of socialism have manifested profoundly the essence of socialism in the aspect of theoretical characteristics,which has laid foundation inevitably in the value relation for understanding the value nature of kernel values of socialism.