V.G. Sapogin - Ph. D. (Phys.-Math.), Professor, Department физики, Academy of Engineering and technology of SFU (Taganrog) E-mail: sapogin@mail.ru N.N. Prokopenko - Dr. Sc. (Eng.), Professor, Head of Department, Don State Technical University (Rostov-on-Don) E-mail: prokopenko@sssu.ru