A knife may include a blade having a first side face and a second side face. The blade may include zirconia as a main component, and include a cutting region including at least a ridge portion between the first side face and the second side face. When a portion including the cutting region in the first side face is referred to as a first cutting face, and a portion including the cutting region in the second side face is referred to as a second cutting face, the proportion of cubic crystals of zirconia in the first cutting face may be larger than the proportion of cubic crystals of zirconia in the second cutting face.

The invention relates to a method for manufacturing a colored blank, which contains zirconium dioxide and is intended for the manufacture of a dental restoration, whereby raw materials in powder form, at least some of which contain one coloring substance each, are mixed with, zirconium dioxide as the main ingredient, the resulting mixture is pressed and subsequently subjected to at least one thermal treatment. To generate the desired fluorescence, it is intended that in the raw materials in powder form one uses as coloring substances at least terbium, erbium, cobalt, as well as one substance that generates a fluorescence effect in the dental restoration, however not iron, aside from naturally occurring impurities.

An alumina-ceramic-based electrical insulator, to a method for producing the insulator, and to a vacuum tube includes the insulator. The electrical insulator is for insulating two electrodes of a vacuum tube through which a charged particle beam flows, the electrical insulator being formed of an alumina-based ceramic. The ceramic comprises a vitreous phase of between 2% and 8% by weight into which at least one metal oxide is diffused from a face of the electrical insulator.

Provided are a polycrystalline phosphor film applicable to a high-power optical device, a preparation method therefor, and a vehicle lamp device using the same, wherein the polycrystalline phosphor film comprises a plurality of phosphor crystals and pores formed between the phosphor crystals, and the phosphor crystal can be a synthesized product comprising at least one rare earth material and cerium (Ce). In addition, the method for preparing a polycrystalline phosphor film can comprise the steps of: preparing a phosphor powder comprising a plurality of phosphor particles; injecting the phosphor powder into a predetermined mold so as to mold the same into a predetermined shape; generating a sintered body by primarily sintering, at a first temperature, the phosphor powder having the predetermined shape; secondarily sintering the sintered body, having been primarily sintered, at a second temperature lower than the first temperature; and forming a polycrystalline phosphor film by processing the sintered body having been secondarily sintered.

A polycrystalline super hard construction comprises a body of polycrystalline super hard material and a substrate bonded to the body along an interface. The substrate a first end surface forming the interface, the first end surface comprising a projection extending from the body of the substrate into the body of super hard material towards the cutting face, the body of polycrystalline material extending around the projection. The body of polycrystalline material comprises a first region more thermally stable than a second region, the first region comprising an annular portion located around the projection, the second region extending between and bonding the first region to the substrate. The first region has a thickness from the cutting face along the peripheral side edge to the interface of at least around 3 mm and a portion of the projection has a thickness measured in a plane extending along the longitudinal axis of at least around 3 mm.

To provide a zirconia mill blank for dental cutting and machining which has excellent machinability in a thin workpiece such as an inlay, an onlay and a veneer, and may impart high strength and high translucency to a zirconia perfect sintered body without a special sintering such as HIP treatment, and a preparing method thereof.

The zirconia mill blank for dental cutting and machining has a porosity within a range of 15 to 30%.

To provide a zirconia mill blank for dental cutting and machining which has excellent machinability in a thin workpiece such as an inlay, an onlay and a veneer, and may impart high strength and high translucency to a zirconia perfect sintered body without a special sintering such as HIP treatment, and a preparing method thereof. The zirconia mill blank for dental cutting and machining has a porosity within a range of 15 to 30%.

When a large-sized silicon nitride substrate having high thermal conductivity is produced, a portion where the thermal conductivity is low is generated, which causes reduction in yield (pass rate). Provided is a silicon nitride substrate in which ?e/?c, which is a ratio of a thermal conductivity ?c at a center portion of the substrate to a thermal conductivity ?e at an end portion of the substrate, is 0.85 to 1.15. Preferably, the silicon nitride substrate has a size of 150 mm?150 mm or more. In the silicon nitride substrate, the ?c and the ?e each are preferably 100 W/m.Math.K or more.

A transition metal catalyst free polycrystalline diamond compact having enhanced thermal stability is disclosed herein. The diamond compact may be attached to a hard metal substrate. The polycrystalline diamond body includes a plurality of diamond grains bonded to adjacent diamond grains by diamond-to-diamond bonds. Sintering of the PCD and the formation of diamond-to-diamond bonding is achieved by transforming graphene treated diamond crystals that are blended with non-metal additives at high pressure and high temperature into a diamond compact that is free of transition metal catalysts. Non-metal additives include vitreous and other non-equilibrium forms of carbon as well as Sr-, K- and Ca-containing carbon sources.

An optical wavelength conversion member and a light-emitting device including the optical wavelength conversion member. The light-emitting device (1) includes a container (3), a light-emitting element (5), and an optical wavelength conversion member (9). The optical wavelength conversion member (9) is composed of a polycrystalline ceramic sintered body containing, as main components, Al.sub.2O.sub.3 crystal grains and crystal grains of a component represented by formula A.sub.3B.sub.5O.sub.12:Ce. Specifically, A and B of the A.sub.3B.sub.5O.sub.12 individually represent at least one element selected from the following element groups: A: Sc, Y, and lanthanoids (except for Ce), and B: Al and Ga; the at least one element selected from the element groups is present in each crystal grain and the crystal grain boundary of the ceramic sintered body; and the element concentration of the crystal grain boundary is higher than the element concentration of the crystal grain.