[1] Faculty of Science Al-Azhar University,
[2] Nasr City,undefined
[3] Cairo,undefined
[4] Egypt,undefined
[5] Faculty of Science El-Minia University,undefined
[6] El-Minia,undefined
[7] Egypt,undefined
[8] Max-Planck-Institut für Quantenoptik,undefined
[9] 85748 Garching,undefined
[10] Germany,undefined