A.L. Khvalin1, V.M. Doroshenko2

1 National Research Saratov State University (Saratov, Russia)
2 Yuri Gagarin State Technical University (Saratov, Russia)
1 Khvalin63@mail.ru, 2 Dorvalentina9@gmail.com

A.L. Khvalin1, V.M. Doroshenko2

1 Saratov National Research State University named after N.G. Chernyshevsky (Saratov, Russia)
2 Saratov State Technical University named after Yu.А. Gagarin (Saratov, Russia)
1 Khvalin63@mail.ru, 2 Dorvalentina9@gmail.com