G.D. Chebotarev - Dr. Sc. (Phys.-Math.), Professor, Department of Physics, Southern Federal University (Rostov-on-Don). E-mail: g_chebotarev@mail.ru E.L. Latush - Dr. Sc. (Phys.-Math.), Professor, Department of Physics, Southern Federal University (Rostov-on-Don). E-mail: ellatush@sfedu.ru