An alumina powder containing: a first alumina particle having average particle diameter from 0.1 μm to 1 μm; a second alumina particle having average particle diameter from 1 μm to 10 μm; and a third alumina particle having average particle diameter from 10 μm to 100 μm, wherein the particle diameters are measured using laser light diffraction scattering particle size distribution analyzer, average sphericity of first alumina particle having projected area equivalent circle diameter from 0.1 μm to 1 μm as determined by microscopy is from 0.80 to 0.98, and a ratio of D90/D10 of first alumina particle is from 2.0 to 8.0 wherein the ratio of D90/D10 is a ratio when particle diameter at cumulative value of 10% from fine particle side of cumulative particle size distribution on volume basis is D10 and particle diameter at cumulative value of 90% from fine particle side is D90.

A method for manufacturing a sapphire single-crystal, including melting alumina and/or sapphire in a crucible, and bringing the molten alumina and/or sapphire in contact with a monocrystalline sapphire seed to make the molten alumina and/or sapphire crystallise progressively according to a growth direction to form the sapphire single-crystal. The monocrystalline sapphire seed has a rhombohedral crystallographic structure defining three crystallographic axes [A], [C] and [M] perpendicular to each other and respectively perpendicular to the crystallographic planes. The monocrystalline sapphire seed is a plate delimited by two planar faces which extend parallel to and at a distance from each other, is obtained from an initial sapphire single-crystal which is cut so that one of the crystallographic axes of the monocrystalline sapphire plate forms with a normal to the planar faces of the monocrystalline sapphire plate an angle whose value is comprised between 5 and 85°.

A method for manufacturing a sapphire single-crystal, including melting alumina and/or sapphire in a crucible, and bringing the molten alumina and/or sapphire in contact with a monocrystalline sapphire seed to make the molten alumina and/or sapphire crystallise progressively according to a growth direction to form the sapphire single-crystal. The monocrystalline sapphire seed has a rhombohedral crystallographic structure defining three crystallographic axes [A], [C] and [M] perpendicular to each other and respectively perpendicular to the crystallographic planes. The monocrystalline sapphire seed is a plate delimited by two planar faces which extend parallel to and at a distance from each other, is obtained from an initial sapphire single-crystal which is cut so that one of the crystallographic axes of the monocrystalline sapphire plate forms with a normal to the planar faces of the monocrystalline sapphire plate an angle whose value is comprised between 5 and 85°.

A catalytic composite comprises a first component selected from Group VIII noble metal components and mixtures thereof, a second component selected from one or more of alkali and alkaline earth metal components, and a third component selected from one or more of tin, germanium, lead, indium, gallium, and thallium, all supported on an alumina support comprising delta alumina having an X-ray diffraction pattern comprising at least three 2θ diffraction angle peaks between 32.0° and 70.0°. The at least three 2θ diffraction angle peaks comprise a first 2θ diffraction angle peak of 32.7°±0.4°, a second 2θ diffraction angle peak of 50.8°±0.4°, and a third 2θ diffraction angle peak of 66.7°±0.8°, wherein the second 2θ diffraction angle peak has an intensity of less than about 0.06 times the intensity of the third 2θ diffraction angle peak.

A catalytic composite comprises a first component selected from Group VIII noble metal components and mixtures thereof, a second component selected from one or more of alkali and alkaline earth metal components, and a third component selected from one or more of tin, germanium, lead, indium, gallium, and thallium, all supported on an alumina support comprising delta alumina having an X-ray diffraction pattern comprising at least three 2θ diffraction angle peaks between 32.0° and 70.0°. The at least three 2θ diffraction angle peaks comprise a first 2θ diffraction angle peak of 32.7°±0.4°, a second 2θ diffraction angle peak of 50.8°±0.4°, and a third 2θ diffraction angle peak of 66.7°±0.8°, wherein the second 2θ diffraction angle peak has an intensity of less than about 0.06 times the intensity of the third 2θ diffraction angle peak.

A hydrogenation catalyst with a small amount of supported metal that is excellent in stability and inhibition of side reactions is provided. The catalyst hydrogenates an aromatic hydrocarbon compound into an alicyclic hydrocarbon compound, and a Group X metal represented by nickel is supported in a composite support including at least alumina and titania. The composite support preferably includes at least an alumina substrate coated with titania. It is also preferable that the Group X metal is prereduced by hydrogen. In the case that the Group X metal is nickel, the nickel content is preferably 5-35 wt % as nickel oxide in the catalyst. The substrate includes, for example, a porous structure formed by a plurality of needle-shaped or column-shaped intertwined three-dimensionally.

A composite membrane for hydrogen separation and purification, including: a modified and activated support, a Palladium (Pd) layer, and an interstice layer between the second surface-modifying layer and the Pd layer. The support includes a support substrate, a first surface-modifying layer on the support substrate, and a second surface-modifying layer on the first surface-modifying layer.

A method of generating hydrogen involving contacting an aqueous solution with an activated aluminum composite including aluminum, AlN, γ-Al.sub.2O.sub.3, and optionally a carbonaceous material. The activated aluminum composite can safely be stored and can be used for safe on demand hydrogen generation in water.

A method of generating hydrogen involving contacting an aqueous solution with an activated aluminum composite including aluminum, AlN, γ-Al.sub.2O.sub.3, and optionally a carbonaceous material. The activated aluminum composite can safely be stored and can be used for safe on demand hydrogen generation in water.

A NaNiCl battery and a module using the same are provided. A NaNiCl battery according to the present invention include: a case that forms an exterior shape of the battery; and a beta alumina solid electrolyte (BASE) tube that is provided in the case and having a clover-shaped cross-section, wherein the case has a clover-shaped cross-section like the clover-shaped cross-section of the BASE tube to minimize a space between the case and the BASE tube.