O.S. Erkovich - Associate Professor, Bauman Moscow State Technical University. E-mail: fn@bmstu.ru P.A. Ivliev - Post-graduate Student, Bauman Moscow State Technical University. E-mail: ivliev-pavel@mail.ru

P.A. Ivliev - Post-graduate Student, Department of Physics, Bauman Moscow State Technical University E-mail: ivliev-pavel@mail.ru