| Affiliation: | 1. Laboratoire de Biophysique, Département de Physique, Faculté des Sciences, Université de Yaoundé I, B.P. 812 Yaoundé, Cameroon;2. Department of Physics, Faculty of Science, University of Bangui, P. O. Box 1450, Bangui, Central African Republic;3. Department of Physics and Astronomy, Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana;4. Laboratoire de Mécanique, Département de Physique, Faculté des Sciences, Université de Yaoundé I, B.P. 812 Yaoundé, Cameroon |
