S.M. Arakelyan - Dr. Sc. (Phys.-Math.), Professor, Head of Dep., Vladimir State University named after A.&N. Stoletovs. E-mail: arak@vlsu.ru A.F. Galkin - Ph. D. (Phys.-Math.), Professor, Vladimir State University named after A.&N. Stoletovs. E-mail: arkad47@mail.ru S.V. Zhirnova - Senior Lecturer, Vladimir State University named after A.&N. Stoletovs. E-mail: svetlanna_vik@mail.ru A.V. Osipov - Junior Research Scientist, Vladimir State University named after A.&N. Stoletovs. E-mail: patifon@mail.ru@mail.ru