1. University Politehnica of Bucharest,Center for Microscopy-Microanalysis and Information Processing,Romania
2. Peking University,State Key Laboratory of Nuclear Physics and Technology,Department of Technical Physics, School of Physics,P.R. China
3. University Politehnica of Bucharest,Center for Research and Training in Innovative Techniques of Applied Mathematics in Engineering “Traian Lalescu”,Romania
4. University of Malta,Faculty of Science,Department of Physics,Msida,Malta