V.G. Shadrov – Ph.D.(Phys.-Math.), Leading Research Scientist, 
Scientific-Practical Materials Research Centre of NAS of Belarus (Minsk)
E-mail: nemtsevich@ifttp.bas-net.by

A.E. Dmitrieva – Junior Research Scientist, 
Scientific-Practical Materials Research Centre of NAS of Belarus (Minsk)
E-mail: nemtsevich@ifttp.bas-net.by

A.V. Boltushkin – Ph.D.(Phys.-Math.), Leading Research Scientist, 
Scientific-Practical Materials Research Centre of NAS of Belarus (Minsk) E-mail: nemtsevich@ifttp.bas-net.by