B. Khuc1, A.L. Gelgor2, T.E. Gelgor3, V.A. Vargauzin4, S.V. Rozov5

1–5 Peter the Great St. Petersburg Polytechnic University (St. Petersburg, Russia)

1 huk.tb@edu.spbstu.ru; 2 agelgor@spbstu.ru; 3 tanya.gelgor@yandex.ru; 4 vargauzinhn@gmail.com; 5 svroz@ya.ru