Loli Yusastri
Department of Physics,
Faculty of Mathematics and Natural Sciences, Universitay of Padjadjaran,
Sumedang, West Java, INDONESIA. Indonesia
I. M. Joni
Department of Physics,
Faculty of Mathematics and Natural Sciences, Universitay of Padjadjaran,
Sumedang, West Java, INDONESIA. Indonesia
C. Panatarani
Department of Physics,
Faculty of Mathematics and Natural Sciences, Universitay of Padjadjaran,
Sumedang, West Java, INDONESIA. Indonesia