Abstract: There is provided a method for preparing an anatase type titanium dioxide photocatalyst having a particle size of nano level without a need of the sintering process at high temperature, and an anatase type titanium dioxide photocatalyst having a particle size nano level. The method for preparing an anatase type titanium dioxide photocatalyst having a particle size of nano level includes adding a titanium-based starting material to a selected solvent and adding an acid or base catalyst to the resulting aqueous solution. Next, subjecting the catalyst-containing aqueous solution to heat treatment at about 80±20° C. to activate peptization thereby preparing an anatase type titanium dioxide sol solution. Finally, the anatase type titanium dioxide sol solution is coated onto a support to complete the preparation of the photocatalyst.

Abstract: Disclosed is a bio-inorganic hybrid composite for retaining and carrying bio-materials with stability and reversible dissociativity, represented by the following chemical Formula I and a method for preparing the same. The bio-inorganic hybrid composite is prepared by (a) coprecipitating with an alkaline material an aqueous solution comprising a bivalent metal (M(II)) and a trivalent metal (N(III)) at a molar ratio satisfying the condition of ⅕≦b/(a+b)≦½ wherein a and b represent a mole number of M and N, respectively, to form a stable layered double hydroxide in which anions are intercalated and (b) subjecting the intercalated anions to ion exchange reaction with a bio-material to compensate for layer charges of the layered double hydroxide. This composite is harmless to the body and artificially controls the appropriate expression of the bio-material retained therein. [M2+1−xN3+x(Oh)2][ABIOn−]x/n.

Abstract: A method for preparing a perpendicularly magnetizable material usable on magnetic recording media comprises the steps of: dissolving at least one member of the group consisting of strontium chloride and strontium nitrate with at least one member of the group consisting of iron chloride and iron nitrate in distilled water; adding citric acid to the resultant solution; controlling the pH of the solution to a range sufficient to completely dissociate the citric acid; heating the resultant solution with stirring to yield a gelatinous precursor; and subjecting the precursor to a temperature sufficiently high to remove the organic constituents thereof, which is characterized by controlling the pH of the solution to gelate the solution without the use of ethylene glycol, and can provide a perpendicularly magnetizable material superior in magnetic and particle properties.