A.K. Murtazaev - Dr. Sci. (Phys.-Math.), Professor, Corresponding Member RAS, Institute of Physics, Dagestan Scientific Center, Russian Academy of Sciences, Makhachkala. E-mail: m_akai2005@mail.ru M.K. Ramazanov - Ph.D. (Phys.-Math.), Senior Research Scientist, Institute of Physics, Dagestan Scientific Center, Russian Academy of Sciences, Makhachkala. E-mail: sheikh77@mail.ru M.K. Badiev - Ph.D. (Phys.-Math.), Senior Research Scientist, Institute of Physics, Dagestan Scientific Center, Russian Academy of Sciences, Makhachkala. E-mail: m_zagir@mail.ru