D.P. Zegzhda - Dr.Sc. (Eng.), Professor department IBKS, National Research University St. Petersburg State Polytechnical University. E-mail: zeg@ibks.ftk.spbstu.ru
A.V. Nikolskiy - Assistant department IBKS, National Research University St. Petersburg State Polytechnical University. E-mail: alexei.nikolsky@ibks.ftk.spbstu.ru