Abstract: A process for producing a tubular casing by folding a flat plastic sheet (1) into a tubular structure by a shaping former (6) as the sheet advances, and joining the meeting edges of the folded sheet to form the tubular casing, characterized by forming grooves (13) on one or both sides of the sheet along fold lines, coating a surfactant (12) on the sheet surface at least at the fold line portions of the sheet surface which are to be brought into contact with the shaping former, and then folding the sheet into a tubular structure by the shaping former.

Abstract: A magazine for electronic devices, prepared by folding a flat plastic sheet into a tubular structure comprises a bottom wall, two side walls and a top wall. At east one and at most three of said walls are partly or entirely formed by a double-sheet structure.

Abstract: There is disclosed a vacuum circuit breaker unit wherein a fixed contact and a movable contact which can be brought into contact with or separated from each other are accommodated in a vacuum valve, as well as a gas circuit breaker unit, in which a fixed contact and movable contact are provided in a sealed container containing insulating gas. The vacuum circuit breaker unit and the gas circuit breaker unit are connected in series and accommodated in an earthed tank with a vacuum valve being surrounded by a decomposition gas-proof sealed container.

Abstract: A filter operable in a microwave frequency band comprises a conductive closed housing having a bottom wall, an upper wall and side walls between said bottom wall and the upper wall, a plurality of resonators fixed on a straight line on the bottom wall inside of the housing, one end of each resonator being grounded to the bottom wall and the other end of each resonator being free standing, each resonator having at least an elongated center conductor and a dielectric body covering the center conductor at least partially in the longitudinal direction of the center conductor, a pair of connectors mounted at the opposite ends at the side walls for coupling the filter with an external circuit, a pair of loops each connected to the inner conductor of said connector and one end of the loops being grounded to the bottom wall, a pair of confronting conductive disks being provided between the free standing end of each center conductor of a resonator and the upper wall to provide the capacitance between said free standin