O.N. Bodin1, F.K. Rakhmatullov2, N.A. Sergeantova3, R.F. Rakhmatullov4, N.E. Kruchinina5, N.V. Lamzin6

1,3,5,6 Penza State Technological University (Penza, Russia)
2,4 Penza State University (Penza, Russia)
1 bodin_o@inbox.ru