| Institution: | 1. Laboratory of Mechanics and Materials, Department of Physics, Faculty of Science, University of Yaoundé I, Yaoundé, Box 812, Cameroon;2. Fundamental Physics Laboratory, Physics of Complex System group, Department of Physics, Faculty of Science, University of Douala, Douala Box 24 157, Cameroon;3. Department of Sciences and Technologies and Salerno unit of CNISM, University of Sannio, Via Port’Arsa 11, Benevento I-82100, Italy;1. Departamento de Física, Universidade Federal da Paraíba, João Pessoa 58051-970, PB, Brazil;2. Departamento de Física, Universidade Estadual de Maringá, Maringá 87020-900, PR, Brazil;3. Institute of Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, P.O. Box 49, Budapest H-1525, Hungary |
