V.V. Zemlyakov - Ph.D. (Phys.-Math.), Associate Professor, Southern Federal University. E-mail: vvzem@yandex.ru G.F. Zargano - D.Sc. (Phys.-Math.), Professor, Southern Federal University. E-mail: zargano@yandex.ru A.A. Gadzieva - Post-graduate Student, Southern Federal University. E-mail: 89185984834@rambler.ru S.V. Krutiev - Student, Southern Federal University. E-mail: sergey-kryt@yandex.ru