Abstract: The present invention relates to a method for producing a hollow fiber membrane sheet-like object including: a connecting process of forming a ring-shaped section by winding a hollow fiber membrane capable of being continuously supplied, around two or more rolls so as to surround the two or more rolls and connecting a leading end portion of the wound hollow fiber membrane and an adjacent hollow fiber membrane, or of putting a ring-shaped section created in advance, on two or more rolls, and connecting a leading end portion of a hollow fiber membrane capable of being continuously supplied, to the ring-shaped section; a winding process of winding the hollow fiber membrane around the rolls by moving the leading end portion of the hollow fiber membrane by rotating at least one roll of the two or more rolls; a fixing process of forming a fixed section by fixing the hollow fiber membrane wound around the two or more rolls, into the form of a sheet in a width direction; and a cutting process of performing cutting-ou

Abstract: The present invention relates to a method for producing a hollow fiber membrane sheet-like object including: a connecting process of forming a ring-shaped section by winding a hollow fiber membrane capable of being continuously supplied, around two or more rolls so as to surround the two or more rolls and connecting a leading end portion of the wound hollow fiber membrane and an adjacent hollow fiber membrane, or of putting a ring-shaped section created in advance, on two or more rolls, and connecting a leading end portion of a hollow fiber membrane capable of being continuously supplied, to the ring-shaped section; a winding process of winding the hollow fiber membrane around the rolls by moving the leading end portion of the hollow fiber membrane by rotating at least one roll of the two or more rolls; a fixing process of forming a fixed section by fixing the hollow fiber membrane wound around the two or more rolls, into the form of a sheet in a width direction; and a cutting process of performing cutting-ou

Abstract: An aluminum composite material as a brake disk material for railroad vehicles is obtained by dispersing and mixing reinforcement particles of alumina, silicon carbide or the like into an aluminum alloy. The reinforcement particles are 5 to 100 .mu.m in diameter, and are dispersed uniformly in the alloy in an amount of 1 to 25% by weight. An extremely excellent brake disk material for railroad vehicles is thus provided which is light in weight and has high strength, good thermal conductivity and high wear resistance.

Abstract: A composite metal material for a friction brake composed of a sliding friction surface metal layer of grey cast iron and a layer of a high strength different metal having a crack transmission resistance. The grey cast iron and high strength different metal are metallurgically bonded together. In this composition metal material, cracks formed in the sliding friction surface metal layer are prevented from spreading by the high strength different metal having a high crack transmission resistance. An intermediate metal layer may be provided if desired.