Thanh toán linh ho?t: Thanh toán ti?n m?t tr?c ti?p khi nh?n tem ho?c thanh toán tr??c qua tài kho?n.Saturation Stage-The purpose at which superior electron emission in the gun is reached devoid of shortening the filament lifetime appreciably.The theoretical resolution described by Abbe for the light microscope is usually modified and applied t