Abstract: A composite oxide for an exhaust gas purification catalyst is provided which can burn PM in diesel engine exhaust gas at low temperatures and has a good S desorption property. The composite oxide for an exhaust gas purification catalyst is composed of Ce, Bi, Pr, R, and oxygen in a molar ratio of Ce:Bi:Pr:R=(1?x?y?z):x:y:z. The ratios of Ce, Bi, Pr, and R satisfy 0<x+y+z?0.5 and preferably 0<x?0.1, 0<y?0.25, and 0<z?0.3. Particularly, when R is Zr, the composite oxide exhibits a good S desorption property at a temperature of about 600° C. and can recover its catalytic activity at low temperatures. Therefore, the exhaust gas purification catalyst is suitable as a PM combustion catalyst.

Abstract: An oxidation catalyst is provided which is capable of combusting PM in a diesel engine exhaust gas at a low temperature and which has low degradation due to heat generated during combustion (i.e., has high heat resistance). A composite oxide for an exhaust gas purification catalyst is formed from Ce, Bi, R, R?, and oxygen, and when the molar ratios of Ce, Bi, R, and R? are expressed as Ce:Bi:R:R?=(1?x?y?z) :x:y:z, it satisfies 0<x?0.4, 0<y<1.0, and 0<z?0.5. Since this composite oxide has no change in its BET value even when treated at a high temperature, and can withstand a high amount of sulfur poisoning, retrogradation due to poisoning is low. Therefore, this exhaust gas purification catalyst is suitable as a PM combustion catalyst.

Abstract: A composite oxide for an exhaust gas purification catalyst is provided which can burn PM in diesel engine exhaust gas at low temperatures and has a good S desorption property. The composite oxide for an exhaust gas purification catalyst is composed of Ce, Bi, Pr, R, and oxygen in a molar ratio of Ce:Bi:Pr:R=(1?x?y?z):x:y:z. The ratios of Ce, Bi, Pr, and R satisfy 0<x+y+z?0.5 and preferably 0<x?0.1, 0<y?0.25, and 0<z?0.3. Particularly, when R is Zr, the composite oxide exhibits a good S desorption property at a temperature of about 600° C. and can recover its catalytic activity at low temperatures. Therefore, the exhaust gas purification catalyst is suitable as a PM combustion catalyst.

Abstract: An oxidation catalyst is provided which is capable of combusting PM in a diesel engine exhaust gas at a low temperature and which has low degradation due to heat generated during combustion (i.e., has high heat resistance). A composite oxide for an exhaust gas purification catalyst is formed from Ce, Bi, R, R?, and oxygen, and when the molar ratios of Ce, Bi, R, and R? are expressed as Ce:Bi:R:R?=(1?x?y?z) :x:y:z, it satisfies 0<x?0.4, 0<y<1.0, and 0<z?0.5. Since this composite oxide has no change in its BET value even when treated at a high temperature, and can withstand a high amount of sulfur poisoning, retrogradation due to poisoning is low. Therefore, this exhaust gas purification catalyst is suitable as a PM combustion catalyst.

Abstract: A Sn-containing In oxide in the form of needles or plates comprising particles having a major axis of 0.1 ?m or less and a minor axis of 0.05 ?m or less.

Abstract: To a hydrochloric acid solution containing In and Sn and which is held at 20° C., an alkali solution is added to adjust pH to 3; the temperature of the mixed solution is raised to 90° C. and the alkali solution is further added to adjust pH to 7.5. The resulting precipitate is recovered by filtration, dehydrated and dried to yield a Sn-containing In hydroxide; the hydroxide is put into a tubular furnace and fired in a nitrogen gas atmosphere containing water vapor and NH3 gas at 600°C. for 2 hours to produce a Sn-containing In oxide in the form of plates having a major axis of 0.041 &mgr;m, a minor axis of 0.025 &mgr;m and a major-to-minor axis ratio of 1.64.

Abstract: A powder for use in the lower layer of a coating magnetic recording medium, comprising acicular particles with a mean major axis length in a range of from 0.01 to 0.5 &mgr;m and a mean minor axis length in a range of from 0.01 to 0.05 &mgr;m, provided that the acicular particles are flat acicular particles which, when cut in a direction perpendicular to the major axis, uniformly exhibit a cross section having a larger width to smaller width ratio of greater than 1, and that the quantity of discharged H2O at 100° C. is in a range of from 0.1 to 2.0% by weight.

Abstract: Iron oxyhydroxide particles that are composed of acicular particles having an average major axis of 0.01 to 0.5 &mgr;m and containing not less than 0.1 wt. % and not more than 30 wt. % of Al in the iron oxyhydroxide and that release not less than 0.1 wt. % and not more than 2 wt. % of H2O at 100° C. are used as particles of a lower layer of a coating type magnetic recording medium having a multi-layer structure. The acicular particles include ones having two or more branches whose branching direction is skewed toward a two-dimensional orientation.

Abstract: Iron oxyhydroxide particles that are composed of acicular particles having an average major axis of 0.01 to 0.5 .mu.m and containing not less than 0.1 wt. % and not more than 30 wt. % of Al in the iron oxyhydroxide and that release not less than 0.1 wt. % and not more than 2 wt. % of H.sub.2 O at 100.degree. C. are used as particles of a lower layer of a coating type magnetic recording medium having a multi-layer structure. The acicular particles include ones having two or more branches whose branching direction is skewed toward a two-dimensional orientation.

Abstract: A coating type magnetic recording medium having a multilayer structure exhibits excellent strength, surface smoothness, and weather resistance is formed on a substrate, and comprises a magnetic layer of magnetic particles dispersed in a resinous binder, and a non-magnetic layer of non-magnetic particles dispersed in a resinous binder. The magnetic particles are composed of acicular ferromagnetic metal particles of Fe containing Co, Al, rare earth elements, periodic table group 1a and 2a elements. The non-magnetic particles are composed of acicular particles of .alpha.-FeOOH.