A GaN semiconductor light-emitting element is provided. One aspect of the invention provides an apparatus for logging into place a drill stem test tool, comprising: a drill string comprising drill pipes or tubings; a drill stem test tool disposed on the drill string; an electromagnetic telemetry tool disposed on the drill string; and a gamma ray tool connected to the electromagnetic telemetry tool. When the present invention is adopted in a single-lens reflex camera, the restraining member can be within the operation path of the restrained portion in the setting operation for photography using an optical finder, and the restraining member can be outside the operation path of the restrained portion in the setting operation for photography using an electronic finder. As a result, the resistance state induced to the channel region is controlled depending on the polarity of the ferroelectric layer, thereby regulating the readwrite operations of the memory cell array. If the user who receives the notification did not make the authentication attempt, then the user alerts the appropriate parties of a breach in security.