Abstract: A display apparatus including a first thin-film transistor, a second thin-film transistor and a third thin-film transistor is provided. The first thin-film transistor includes a first active layer composed of a polysilicon material, a first gate electrode overlapping the first active layer such that a first gate insulating layer is interposed therebetween, a first source electrode and a first drain electrode. The first gate electrode includes n layers. The first source electrode and the first drain electrode are connected to the first active layer. The second thin-film transistor includes a second active layer composed of a polysilicon material, a second gate electrode overlapping the second active layer such that a first gate insulating layer is interposed therebetween, a second source electrode and a second drain electrode. The second gate electrode includes n+1 layers. The second source electrode and the second drain electrode are connected to the second active layer.

Abstract: A fuel cell recovery control system and method are provided to supply hydrogen to the cathode of a fuel cell stack to remove an oxide film formed on a platinum surface of the cathode. The performance of the fuel cell stack is recovered in accordance with the oxide film removal. In addition, electric power generated during the performance recovery of the fuel cell stack is consumed in an inverter and, as such, overcharge of a battery is prevented.

Abstract: A fuel cell system for enabling maintenance of a stack module without stopping operation thereof, and a method of replacing a stack module of the fuel cell system are provided. The fuel cell system includes a plurality of stack modules that are connected in parallel to a hydrogen line and an air line. Two or more of the stack modules are connected to form a group, and an inverter is connected to the group of the stack modules and is capable of being turned on and off.