P.R. Pokhrel School of Science, Kathmandu University, Dhulikhel, Kavre, GPO Box 6260, Kathmandu, Nepal; Department of Mathematics, R.R. Campus, Tribhuvan University, Nepal Nepal
K.B. Khattri School of Science, Kathmandu University, Dhulikhel, Kavre, GPO Box 6260, Kathmandu, Nepal;
P. Kattle School of Science, Kathmandu University, Dhulikhel, Kavre, GPO Box 6260, Kathmandu, Nepal;
J. Kafle School of Science, Kathmandu University, Dhulikhel, Kavre, GPO Box 6260, Kathmandu, Nepal;
D.B. Gurung School of Science, Kathmandu University, Dhulikhel, Kavre, GPO Box 6260, Kathmandu, Nepal;
S.P. Pudasaini School of Science, Kathmandu University, Dhulikhel, Kavre, GPO Box 6260, Kathmandu, Nepal;