V.Ya. Yavchunovsky – Dr.Sc. (Phуs.-Math.), General Director, 

SPC «ETNA PLYUS» (Saratov)

E-mail: vyy@etna.su

A.K. Kobets – Post-graduate Student, 

Department of Solid State Physics, 

Saratov National Research State University named after N. G. Chernyshevsky

E-mail: cobets.alexander@yandex.ru

V.A. Tolstov – Under-graduate Student, 

Department of Electric Power Engineerig and Electrotechnology, 

Yuri Gagarin State Technical University of Saratov 

E-mail: v.tolstof@yandex.ru 

E. I. Yusov – Engineer, 

SPC «ETNA-PLYUS» (Saratov) 

E-mail: yusov.evgeniy@etna.su