Abstract: A low-profile gas purifying apparatus includes a plurality of conductive plates each having a serrated portion at the periphery thereof. The plates are disposed opposite a flat electrode which is coated with a dielectric layer and are separated from the flat electrode by a predetermined gap. A high voltage A.C. power source is connected between the plates and the flat electrode. The plane surfaces of the conductive plates are slanted with respect to the gas flow direction to reduce flow resistance through the apparatus.

Abstract: An exhaust gas purifier unit has a bridged stream corona generator, an oil feeder for feeding oil to the bridged stream corona generator and an oil supplier for supplying an engine with oil stored in and flowing out of the bridged stream corona generator, so as to remove harmful gases contained in the exhaust gas, reliably over an extended period of time.

Abstract: A laser tube including an anode and a hollow cathode and adapted to obtain laser oscillation by utilizing a negative glow generated in a space within the hollow cathode. The laser tube has an elongate cylindrical member in which the anode and the hollow cathode are disposed opposite to each other, and the hollow cathode has formed therein a plurality of holes for communication between its internal space and the space outside thereof. The laser tube may further include a conducting grid provided in proximity to the anode and a conducting grid provided in a cathode dark space.