Abstract: An ink jet recording medium for a pigment ink, which including a substrate, a porous layer of alumina hydrate having a thickness of from 1 to 200 &mgr;m, formed on the substrate, and a water-soluble resin layer having a thickness of from 0.01 to 50 &mgr;m, formed as an upper layer thereon.

Abstract: A recording medium for pigment ink, which comprises a substrate, a porous layer comprising alumina hydrate, formed on the substrate, and a pigment-fixing layer comprising agglomerates having an average agglomerate particle size of from 0.1 to 0.5 &mgr;m or monodisperse particles having an average primary particle size of from 0.1 to 0.5 &mgr;m, formed on the porous layer.

Abstract: A recording sheet of the type on which an ink containing a water-soluble polymer is applied by an ink jet system for recording, which comprises a substrate and a porous alumina hydrate layer containing a gelling agent for the water-soluble polymer, formed on the substrate.

Abstract: An alumina sol coating fluid containing an alumina hydrate and a polyvinyl alcohol and having boric acid or a borate incorporated therein.

Abstract: A recoding sheet comprising a substrate, a porous layer of pseudo-boehmite having a thickness of from 10 to 100 .mu.m formed on the substrate and a layer of silica gel having a thickness of from 0.1 to 30 .mu.m formed on the porous layer of pseudo-boehmite.

Abstract: The present invention relates to a method for producing a tobacco raw material having at least a part of its surface coated with a silical gel, which comprises adding silica sol to the tobacco raw material and subjecting the silical gel to gelation.

Abstract: A recording film comprising a transparent substrate, a porous alumina hydrate layer formed on the substrate and an opaque porous layer laminated on the alumina hydrate layer.

Abstract: A recording sheet for an ink jet printer, which comprises a substrate, a lower layer of porous pseudo-boehmite having an average pore radius of from 20 to 80 .ANG. formed in a thickness of from 5 to 60 .mu.m on the substrate and an upper layer of porous pseudo-boehmite having an average pore radius of from 40 to 150 .ANG. formed in a thickness of from 2 to 30 .mu.m on the lower layer, the average pore radius of the upper layer being larger than that of the lower layer.

Abstract: A recording sheet comprising a substrate and a porous layer of ink absorbent formed thereon, wherein the porous layer of ink absorbent is made mainly of pseudo-boehmite.

Abstract: A recording sheet comprising a sheet of paper and porous particles provided on the paper surface, said porous particles having an average pore size of from 10 to 5000 .ANG., a pore volume of from 0.05 to 3.0 cc/g and an average particle size of from 0.1 to 50 .mu.m.

Abstract: Calcium phosphate type crystallizable glass for dental materials, which is composed essentially of from 41 to 49.5 mol % of CaO, from 50 to 58.5 mol % of P.sub.2 O.sub.5 and from 0.5 to 5 mol % of Al.sub.2 O.sub.3, and which has an atomic ratio of calcium to phosphorus (Ca/P) within a range of from 0.35 to 0.49.

Abstract: A method for synthesizing amorphous silicon nitride, wherein silicon halide and ammonia are reacted in a reaction vessel at a high temperature in the absence of oxygen to thereby synthesize powder of amorphous silicon nitride, then the powder is separated from a gas containing therein gaseous ammonia halide which has been produced simultaneously with said amorphous silicon nitride by use of a collecting means, comprises directly mixing, in advance of the separation, cool gas containing therein neither oxygen nor moisture into said gas to cool down said powder and gas so that both substances may be put in said collecting means without deposition of ammonium halide to the inner wall of the reaction vessel, and other component parts.

Abstract: A process for synthesizing silicon nitride by reacting a silicon halide and ammonia at a high temperature, which is characterized in that at least while the reaction product is amorphous, hydrogen and chlorine are burned in the reaction zone where a halogen containing inorganic silicon compound and ammonia are reacting, and the reaction of said reactants is effected by the heat of combustion thus obtained.