Abstract: A process for production of a composite porous film wherein a porous support, of which both sides have been coated with a solution (dope) of an organic polymer compound in a water-soluble organic solvent to form a coated film, is passed through an air gap step and conveyed into a coagulating bath comprising water or a mixture of water with the same solvent as the organic solvent, and is then immersed in the coagulating bath so that the coated film on both surfaces of the porous support directly contact the coagulating bath for coagulation, and is then washed and dried. This production process is suitable for production of non-aqueous secondary battery separators, and yields non-aqueous secondary battery separators with good handling properties and at low cost, whereby the ion permeability, adhesion with electrodes and electrolyte solution retention can be strictly controlled.

Abstract: A process for production of a composite porous film wherein a porous support, of which both sides have been coated with a solution (dope) of an organic polymer compound in a water-soluble organic solvent to form a coated film, is passed through an air gap step and conveyed into a coagulating bath comprising water or a mixture of water with the same solvent as the organic solvent, and is then immersed in the coagulating bath so that the coated film on both surfaces of the porous support directly contact the coagulating bath for coagulation, and is then washed and dried. This production process is suitable for production of non-aqueous secondary battery separators, and yields non-aqueous secondary battery separators with good handling properties and at low cost, whereby the ion permeability, adhesion with electrodes and electrolyte solution retention can be strictly controlled.

Abstract: A prestressed concrete structure comprising an elongated concrete molded article having a pair of side surfaces opposed to each other, a plurality of tensile members laterally extending through the concrete molded article to be secured at each end to the side surfaces of the concrete molded article in a tensioned state and imparting a compressive load to the concrete molded article, side guards arranged along both side surfaces of the concrete molded article so as to cover the ends of the tensile members, and reinforcing members arranged on the side surfaces of the side guards in order to prevent the broken tensile members from protruding beyond the side surfaces thereof breaking through the side guards when the tensile members in the tensioned state are broken.