Abstract: A zirconia material manufacturing method includes: dispersing hydroxyapatite powder in water to prepare a slurry having a hydroxyapatite powder concentration of 1%; and dipping zirconia in the slurry to form, on the zirconia, a coating layer containing hydroxyapatite.

Abstract: Provided are a substrate for epitaxially growing a diamond crystal, having at least a surface made of a metal, in which the above surface made of the metal is a plane having an off angle ? of more than 0°, and the full width at half maximum of the X-ray diffraction peak from the (002) plane by the X-ray rocking curve measurement at the above surface made of the metal is 300 seconds or less; and a method of manufacturing a diamond crystal, including epitaxially growing a diamond crystal on the above surface made of the metal of the above substrate.

Abstract: The Ga2O3-based single crystal substrate has an amount of warpage of ?50 ?m or more and 50 ?m or less (including 0 ?m) on a main surface. The method of manufacturing a Ga2O3-based single crystal substrate includes processing a substrate from a Ga2O3-based single crystal grown according to an induction heating type single crystal growth method to have an amount of warpage of ?50 ?m or more and 50 ?m or less (including 0 ?m) on a main surface.

Abstract: An optical connector includes: at least a ferrule and n self-forming optical waveguides, wherein the ferrule includes n optical fiber insertion holes, and optical fibers are each inserted into and included in the optical fiber insertion holes, the number n indicates a natural number not including zero, there are variations in an angle of each optical fiber in a core axial direction and a core gap between adjacent ones of the optical fibers, an end surface of the ferrule is formed with roundness, and end portions of the self-forming optical waveguides are each optically connected to the optical fibers.