Abstract: The invention provides a surface-modified titanium dioxide particle inhibited in photocatalytic activity and reduced in amount of volatile water. The surface-modified titanium dioxide particle has on the surface a crystalline composite compound of at least one of alkaline earth metals selected from magnesium, calcium, barium and strontium complexed with titanium dioxide in an amount of 0.1-20% by weight based on the weight of the surface-modified titanium dioxide particle in terms of oxide of the alkaline earth metal. The surface-modified titanium dioxide particle is produced by heating a compound of an alkaline earth metal and a titanium dioxide particle at a temperature of 60° C. or higher so that the alkaline earth metal is complexed with titanium dioxide to form a crystalline composite compound on the surface of the titanium dioxide particle in an amount of 0.1-20% by weight based on the weight of the surface-modified titanium dioxide particle in terms of oxide of the alkaline earth metal.

Abstract: The invention provides a surface-modified titanium dioxide particle inhibited in photocatalytic activity and reduced in amount of volatile water. The surface-modified titanium dioxide particle has on the surface a crystalline composite compound of at least one of alkaline earth metals selected from magnesium, calcium, barium and strontium complexed with titanium dioxide in an amount of 0.1-20% by weight based on the weight of the surface-modified titanium dioxide particle in terms of oxide of the alkaline earth metal. The surface-modified titanium dioxide particle is produced by heating a compound of an alkaline earth metal and a titanium dioxide particle at a temperature of 60° C. or higher so that the alkaline earth metal is complexed with titanium dioxide to form a crystalline composite compound on the surface of the titanium dioxide particle in an amount of 0.1-20% by weight based on the weight of the surface-modified titanium dioxide particle in terms of oxide of the alkaline earth metal.

Abstract: The invention provides a titanium dioxide pigment particle inhibited in photocatalytic activity and reduced in amount of volatile water which has on the surface a composite compound of alkaline earth meta complexed with the titanium dioxide in an amount of 0.1-20% by weight based on the weight of the titanium dioxide pigment particle in terms of oxide of the alkaline earth metal, wherein the composite compound is obtained by heating a compound of at least one of alkaline earth metals selected from magnesium, calcium, barium and strontium and a titanium dioxide particle at a temperature of 60° C. or higher so that the alkaline earth metal is complexed with the titanium dioxide on the surface of the titanium dioxide pigment particle.

Abstract: A process for the production of fine powder of metallic nickel which comprises a first step of dissolving nickel carbonate and/or nickel hydroxide in aqueous ammonia or in an aqueous solution of ammonia and at least one selected from the group consisting of ammonium carbonate, ammonium hydrogencarbonate, a carbonate of an alkali metal and a hydrogencarbonate of an alkali metal to prepare an aqueous solution of a nickel salt; converting the aqueous solution of a nickel salt to a W/O emulsion, and then removing volatile components including ammonia from the droplets to form precipitates of nickel carbonate in the droplets, thereby providing fine spherical particles of nickel carbonate; and a second step of heating the particles of nickel carbonate in the presence of a fusion preventive agent that is a compound of at least one element selected from the group consisting of alkaline earth elements, aluminum, silicon and rare earth elements in an atmosphere of hydrogen, thereby reducing the nickel carbonate to meta

Abstract: The invention provides a process for production of fine spherical particles of a carbonate or a hydroxide of nickel, cobalt or copper which comprises: dissolving a carbonate or a hydroxide of nickel, cobalt or copper having the general formula (I) M(CO3)x/2.(OH)y wherein M represents Ni, Co or Cu, and x and y are numerals satisfying the followings: 0≦x≦2, 0≦y≦2 and x+y=2, in aqueous ammonia, converting the resulting solution to a W/O emulsion containing droplets of the solution in a non-aqueous medium, and then removing volatile components including ammonia from within the droplets, thereby precipitating a basic carbonate or a hydroxide of a metal selected from nickel, cobalt and copperin the droplets.

Abstract: A multilayer piezoelectric composite comprising a bonded laminate each layer of which is composed of a green sheet of a low-temperature sintering lead zirconate titanate piezoelectric ceramic. The temperature coefficient of a frequency constant of at least one layer has a polarity opposite to the polarity of those of the other layers. The bonded laminate is sintered at a temperature which does not produce any or almost any interdiffusion between layers so that the absolute value of the temperature coefficient of a frequency constant of the bonded laminate is smaller than the absolute value of the temperature coefficient of a frequency constant of any or one of the layers.

Abstract: A composite dielectric is formed with a matrix synthetic resin and particulate porous, inorganic dielectric dispersed in the matrix synthetic resin. The dielectric constant of this composite dielectric can be thereby elevated effectively without enlarging the dissipation factor (tan .delta.) of the composite dielectric.

Abstract: A method and apparatus for the maintenance of snow quality on an indoor artificial ski slope. The snow quality of the slope, comprising a thin compacted surface layer and a deep unfused base layer, is maintained by promptly managing against the variations of snow quality due to various heat sources. The old surface layer snow is replaced with fresh snow on a daily basis, while deterioration of the snow base layer is prevented by air conditioning and refrigeration means. The old snow is melted, filtered, and used to make new snow, to air condition the slope, and to expedite melting of yet additional old snow.

Abstract: A process for producing a powder material for niobium-containing lead perovskite ceramics represented by the general formula:PbA.sub.x Nb.sub.1-x O.sub.3,wherein X=1/2 or 1/3, A represents at least one element selected from the group consisting of Fe, Co, Cr, Ni, Mn, Mg, Zn, Cd, Zr, In, Cu and Hf. A dried mixture of a sol or a suspension of a hydroxide a component A which has a lower activity than Pb and a niobic acid sol is first calcinated. A Pb compound is then added with the mixture and the resultant mixture is calcinated again.

Abstract: A process for producing a peroxoniobic acid sol which comprises: adding a strong acid, hydrogen peroxide and water to at least one niobium compound selected from the group consisting of niobium hydroxide, niobium oxide and niobium pentachloride to provide an aqueous solution of peroxoniobic acid; and then maintaining the aqueous solution at a temperature of 5.degree.-50.degree. C.

Abstract: A composition for producing ceramic dielectrics which comprises: a mixture of barium titanate which has average particle size of 0.1-1.5 .mu.m is amounts of 98-60 mole % and a perovskite type barium titanate solid solution which has average particle size of 0.1-1.5 .mu.m and a Curie temperature of 50.degree.-115.degree. C. in amounts of 2-40 mole %; and(A) at least one of niobium oxides and tantalum oxides in amounts of 0.3-2 moles % in relation to 100 mole % of the mixture; and(B) at least one of cobalt oxides, nickel oxides, magnesium oxides, manganese oxides, copper oxides and oxides of a rare earth metal in amounts of 0.1-2 moles % in relation to 100 mole % of the mixture.The composition provides a ceramic dielectric which has a large relative permittivity and still has a small temperature dependence of relative permittivity within .+-.15% over a temperature range between -55.degree. C. and +125.degree. C. taking a relative permittivity at 20.degree. C. as a standard.

Abstract: An .alpha.-olefin polymerization catalyst which comprises a perovskite type complex compound comprising a perovskite type compound represented by the formulaABO.sub.3wherein A is at least one element selected from the group consisting of alkaline earth metals and Pb, and B is at least one element selected from the group consisting of Ti, Zr, Hf and Sn; the complex compound further containing at least one oxide of element selected from the group consisting of rare earth elements, transition elements, Bi, Sb and Sn doped in the perovskite type compound in an amount of 0.1-3 mol %.A composite material which comprises the catalyst having an .alpha.-olefin polymer deposited thereon, is useful as, for example, a dielectric ceramic material.

Abstract: A molded catalyst for fitting into a reactor vessel having an inlet and an outlet for a reactant gas, the catalyst having openings therethrough parallel to the direction of a reactant gas which is introduced into the reactor vessel from the inlet, the catalyst comprising: a wear-resistant front surface facing the inlet of the reactor vessel and a continuation of the front surface extending therefrom, the both being the front portion of the catalyst, and the remaining part of the catalyst made so wear-susceptible as to have either:(a) a wearability of 2-10% in a shaking abrasion test wherein grinding particles having an average particle size of 100 .mu.m and a Mohs scale of 9 are placed in the openings of the catalyst in an amount of 50% by volume based on the total volume of the openings, and the catalyst is shaked for three hours with an amplitude of 77 mm and a frequency of 320 per minute; or(b) a wearability of 7.

Abstract: A molded catalyst for fitting into a reactor vessel having an inlet and an outlet for a reactant gas, the catalyst having openings therethrough parallel to the direction of a reactant gas which is introduced into the reactor vessel from the inlet, the catalyst comprising: a wear-resistant front portion facing the inlet of the reactor vessel, and the remaining portion of the catalyst made so wear-susceptible as to have either:(a) a wearability of 2-10% in a shaking abrasion test wherein grinding particles having an average particle size of 1000 .mu.m and a Mohs scale of 9 are placed in the openings of the catalyst in an amount of 50% by volume based on the total volume of the openings, and the catalyst is shaken for three hours with an amplitude of 77 mm and a frequency of 320 per minute; or(b) a wearability of 7.5-35% in an air abrasion test wherein an air which contains silica particles having an average particle size of 40 .mu.m in amounts of 70 g/m.sup.

Abstract: A process for producing a composition which includes a perovskite compound, the process comprising:(a) subjecting a mixture of a hydroxide of at least one A group element selected from the group consisting of Mg, Ca, Sr, Ba, Pb and rare earth elements and a hydroxide of at least one B group element selected from the group consisting of Ti, Zr, Hf and Sn, to the hydrothermal reaction in an aqueous reaction medium;(b) adding an insolubilizing agent to the resultant reaction mixture to insolubilize water-soluble compounds of the unreacted A group element dissolved in the aqueous medium so as to adjust the ratio of the group A element to the group B element in a resulting composition to a desired A/B ratio; or(c) filtering, washing with water and drying the resultant reaction mixture to provide a solid reaction product, dispersing the reaction product in an aqueous medium to form a slurry, adding to the slurry a water-soluble compound of the A group element, and then adding to the slurry an insolubilizing agent t

Abstract: A method is provided for producing a catalytic structure in the form of sheet or honeycomb for the gas phase reduction of nitrogen oxides. The method comprises: beating an inorganic fiber in water to form a slurry; forming the slurry into a sheet by paper-making means and drying the sheet; impregnating the sheet or a honeycomb structure manufactured therefrom which has a porosity of 60-85% with an impregnating slurry which contains titanium dioxide or its precursor in a concentration at least of 100 g/l and has a viscosity of 5-250 cps. at normal temperatures, drying, and when necessary calcining the structure; and then immersing the structure in a solution containing a catalytically active agent or its precursor, drying and calcining the structure, thereby to provide a porous catalytic structure having titanium dioxide and the catalytically active agent substantially uniformly dispersed and supported therein.

Abstract: A method is provided for producing a catalyst and a carrier therefor in the form of sheet or honeycomb. The method comprises: beating a heat-resistant fiber such as asbesto fiber in water to form a slurry; mixing the slurry with a catalytically active agent, a carrier material therefor and/or their precursors to fix such materials in the fiber, thus forming a stock; and forming the stock into a sheet and drying the same. The sheet thus obtained may be formed into a honeycomb structure with an improved adhesive.

Abstract: A method for packing catalysts comprising packing the catalysts having through-holes in the direction of the flow of the gas with plurality of them being arranged in the direction of the flow of the gas through the catalyst-packed layers, characterized by arranging the catalysts in such manner that the sections of the connecting parts in the direction of the flow of the gas do not lie on the same plane as at least one of the above sections of the connecting parts formed by the adjacent catalysts.

Abstract: In a method for treating a gas containing dusts therein under a monolithic catalyst consisting of a ceramic support which is substantially porous throughout the structure, and has active ingredients uniformly dispersed therein and passages therethrough parallel to the flow of the gas for allowing the gas to pass therethrough, the improvement in which the catalyst has the sintered front portion or has a vitreous coating on the front portion. Alternatively, the improvement in which a metal or sintered ceramic lid having openings therethrough is fixed onto the front face of the catalyst with the passages in alignment with the openings of the lid.

Abstract: A method is provided for producing a catalyst and a carrier therefor in the form of sheet or honeycomb. The method comprises: beating a heat-resistant fiber such as asbesto fiber in water to form a slurry; mixing the slurry with a catalytically active agent, a carrier material therefor and/or their precursors to fix such materials in the fiber, thus forming a stock; and forming the stock into a sheet and drying the same. The sheet thus obtained may be formed into a honeycomb structure with an improved adhesive.