| Institution: | 1. Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaoundé, Cameroon;2. Centre d’Excellence Africain en Technologies de l’Information et de la Communication (CETIC), University of Yaounde I, P.O. Box 812, Yaoundé, Cameroon;3. The Abdus Salam International Centre of Theoretical Physics, P.O. Box 506-Strada Costiera, Trieste II-34014, Italy;1. School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, PR China;2. School of Science, Yanshan University, Qinhuangdao, Hebei 066004, PR China |
