Abstract: A fixing unit or device that can be used in an image forming apparatus includes a first heater element that is formed of a material that increases in electrical resistance with increases in temperature. A controller of the fixing unit is configured to vary a duty ratio of electric power applied to the first heater element during a start-up operation in which the temperature of the first heater element is raised to a target operating temperature. By varying the duty ratio during the start-up operation, changes in the resistance of the first heater element with the heating can be compensated. For example, the duty ratio can be increased during the course of the start-up to achieve the target operating temperature faster.

Abstract: This variable damper system for a bridge is installed between a superstructure and a substructure of a bridge and can freely change the damping characteristics so that the inertial force of the superstructure generated in an earthquake will be distributed to the substructure and the vibration will be reduced, and all the functions of a viscous damper/stopper, an energy absorber, and a stopper for preventing excessive response with a shock absorber have been integrated in one unit of this system, so that one unit of this system can perform the same functions as those carried out by a plurality of conventions devices each having an independent function and also a narrow space on the top surface of the substructure of a bridge can be used as it is.