Abstract: An energy storage apparatus has developed for railway vehicles by adopting a bidirectional DC-DC converter to increase the efficiency of charge/discharge, comprising that; a power receiving unit, filter unit, charging unit storage unit having a plurality of super-capacitors, capacitor monitoring unit, a plurality of bidirectional DC-DC converters arranged in parallel, and voltage detector electrically connected to the filter unit, current detector for detecting the currents flowing. The controller further comprises; an analog interface board, signal identifying board, signal control board, digital output contact unit, communicating board, PWM control board, optical output board, external gate driver. The PWM control board includes; a sensor input circuit, A/D converter, calculation unit, calculation control processor, and power monitoring unit.

Abstract: A steel structure including pre-stressing brackets for improving load-carrying capacity and serviceability comprises: a steel girder; a plurality of connecting brackets connected to the bottom surface of the steel girder spaced and apart from one; and a cover plate connected to the bottom surfaces of the connecting brackets. Since the cover plate is installed regardless of the connecting portion of the steel girder, pre-stressing section can be consecutively formed therefore pre-stress effect is improved. Moreover, since the connecting brackets space the cover plate a constant distance from the steel girder, the moment of inertia is increased so the span of a bridge might be increased.