Zhenirovskyy M. Effective kinetic coefficients of macroscopically strongly inhomogeneous mediums with nonlinearity and small dissipation.

The thesis deals with theoretical investigation of the effective kinetic coefficients of the macroscopically strongly inhomogeneous mediums with nonlinearity and small dissipation. The approximate method that enables to obtain the concentration and field dependences of effective conductivity with nonlinear phases in an analytical form has been developed. The effective properties of two-phase composites have been considered in a case when one of the phases is the ferromagnetic medium and another one is some linear medium. It has been found that the approximate methods describe satisfactorily the field and concentration dependences up to value of a field at which the effective conductivity has the maximum value. The disorder effect on the conductivity of the two-phase strongly inhomogeneous highly filled composites has been in the linear case investigated. It is shown, that in the linear case the weak disorder does not destroy scaling concentration dependence of effective conductivity on the closeness topercolation threshold . A composite material with negligibly real part of the local conductivity of phases and imaginary parts of the different signs has been studied. For such composites the paradox of finite energy absorption has been explained and it has been found that the correlation radius grows to infinite and the concept of effective conductivity loses physical sense. It has also been shown that the existence of fluctuations of conductivity with a nonzero real part leads to the finite correlation radius that is to the self- averaging system.