1. International Tomography Center, Siberian Branch, Russian Academy of Sciences, Institutskaya St. 3a, Novosibirsk 630090, Russia
2. Novosibirsk State University, Pirogova St. 2, Novosibirsk 630090, Russia
3. Institute of Computational Modeling, Siberian Branch, Russian Academy of Sciences, Akademgorodok 50/44, Krasnoyarsk 660036, Russia