A portable electronic device includes a main body, a battery, and a battery fixing mechanism including a button disposed through a button hole of the main body, first and second rod members, a first linkage rod pivoted to the first rod member and disposed in an oblique slot of the button, first and second transverse elastic members, and a rail member having transverse, oblique, and incurve rails. The recessed light fixture rotation ring has a mechanical brake for locking the ring in place after positioning of the lamp. This technique enables the electrolyte to be formed by photolithography and etching without causing any damage thereto. Messages are then received from the broadcast entity, the messages associated with the predetermined feature. In one embodiment, the method includes topically applying a device including an anode containing zinc.