V.I. Parfenov1, Bui Trong Tien2, Cong Minh Tuan3, A.V. Terekhov4

1,2 Voronezh State University (Voronezh, Russia)

2 National Research University “MPEI” (Moscow, Russia)

1 vip@phys.vsu.ru, 2 trongtienpt98@gmail.com, 3 kongm@mpei.ru, 4 aleksandr-terekhov@ya.ru

V.M. Artyushenko1, V.I. Volovach2

1 Moscow State University of Geodesy and Cartography (Moscow, Russia)

2 Volga Region State University of Service (Toglyatti, Russia)

2 MIREA - Russian Technological University (Moscow, Russia)

1 artuschenko@mail.ru; 2 volovach.vi@mail.ru