Abstract: An optical information recording medium is composed of a transparent substrate, a recording layer provided on the substrate, which is transparent with respect to a light beam for reproducing information recorded in the recording layer, a reflection layer provided on the recording layer, and an anti-reflection layer provided on the back side of the substrate opposite to the recording layer. The anti-reflection layer is composed of a plurality of overlaid layers, and at least one of the layers being a transparent electroconductive layer and the other layers are transparent insulating layers.

Abstract: A spacer for brazing having a main body made of a steel plate such as a hot rolled steel plate, a stainless steel plate or the like and a coating provided on the surfaces of the main body by a flame spraying process such as a metal spraying process or a plasma spraying process. The coating is an inorganic substance which is low in wettability in relation to a brazing filler metal. When the brazing filler metal is a copper series one, the inorganic substance is a metal oxide such as a lumina, zirconia, a mixture of zirconia and titania, magnesium zirconate or the like, or an inorganic nitride such as boron nitride or the like.

Abstract: Method of manufacturing a blade wheel including setting a plurality of blades into a first jig, positioning an annular core member thereover with mating projections on the blades with slits on the core member, welding at the mating points, setting the sub-assembly thus produced onto a shell member held in another jig with claw members of the blades engaging peripherally located slots in the shell member, and securing the two together with an annular retainer member with grooves engaging other claw members on the blades being spot welded to the shell member.