Abstract: A gas laser oscillation apparatus of orthogonal excitation type includes an electric discharge region having a pair of electric discharge electrodes, an axial flow blower having a plurality of rotor vanes and working by a permanent magnet motor, a first heat exchanger having a plurality of cooling fins, the cooling fins arranged on a plane perpendicular to an optical axis, a second heat exchanger having a plurality of cooling fins, the cooling fins arranged on a plane perpendicular to the optical axis, a gas duct having a gas passageway and arranged between the electric discharge region and the first heat exchanger, the axial flow blower being arranged on the gas passageway. The axial flow blower is arranged on a windward side of the first heat exchanger. The second heat exchanger is arranged on a windward side of the axial flow blower.

Abstract: In a rectifier device (2) for full-wave rectifying an output of a vehicle alternating-current generator (1), a schottky barrier diode having a characteristic whose forward voltage drop with respect to a forward current is small and whose reverse leakage current is small, is used as a rectifier semiconductor element (201),(202) constituting the rectifier device (2).

Abstract: A railway-train communication apparatus transmits a first transmission signal flowing through an inter-car network between cars of a railway train and a second transmission signal flowing through an in-car network in each of the cars. A node device includes a first signal converter and a second signal converter that perform a signal conversion between the first transmission signal and the second transmission signal and a layer 2 switch arranged between the first signal converter and the second signal converter for connecting the first signal converter and the second signal converter. A first controller is connected to the layer 2 switch.