A mullite sintered body according to the present invention has an impurity element content of 1% by mass or less and contains sintered mullite grains having an average grain size of 8 μm or less. When a surface of the mullite sintered body is finished by polishing, pores in the surface have an average largest pore length of 0.4 μm or less. The surface preferably has a center line average surface roughness (Ra) of 3 nm or less. The surface preferably has a maximum peak height (Rp) of 30 nm or less. The number of pores in the surface is preferably 10 or less per unit area of 4 μm×4 μm.

A ceramic substrate is formed of a polycrystalline ceramic and has a supporting main surface. The supporting main surface has a roughness of 0.01 nm or more and 3.0 nm or less in terms of Sa. The number of projections and depressions with a height of 1 nm or more in a square region with 50 μm sides on the supporting main surface is less than 5 on average, and the number of projections and depressions with a height of 2 nm or more in the square region is less than 1 on average.

A cordierite-based sintered body according to the present invention contains cordierite as a main component and silicon nitride or silicon carbide. The cordierite-based sintered body preferably has a thermal expansion coefficient less than 2.4 ppm; ° C. at 40° C. to 400° C., an open porosity of 0.5% or less, and an average grain size of 1 μm or less.

A mullite-containing sintered body according to the present invention contains mullite and at least one selected from the group consisting of silicon nitride, silicon oxynitride, and sialon. It is preferable that the mullite-containing sintered body have a thermal expansion coefficient of less than 4.3 ppm/° C. at 40° C. to 400° C., an open porosity of 0.5% or less, and an average grain size of 1.5 μm or less.

Electronic devices are produced from dielectric compositions comprising a mixture of precursor materials that, upon firing, forms a dielectric material comprising a barium-strontium-titanium-tungsten-silicon oxide.

To provide a zinc oxide-based varistor that exhibits adequate characteristics without using antimony. Disclosed is a sintered body for a varistor, including zinc oxide as a main component; 0.6 to 3.0 mol % of bismuth oxide in terms of bismuth (Bi); 0.2 to 1.4 mol % of cobalt oxide in terms of cobalt (Co); 0.1 to 1.5 mol % of chrome oxide in terms of chrome (Cr); and 0.1 to 1.5 mol % of manganese oxide in terms of manganese (Mn), wherein the contents of antimony (Sb), a rare earth element and tin (Sn) are not more than a level of impurities.

A ceramic waveguide includes: a doped metal oxide ceramic core layer; and at least one cladding layer comprising the metal oxide surrounding the core layer, such that the core layer includes an erbium dopant and at least one rare earth metal dopant being: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, thulium, ytterbium, lutetium, scandium, or oxides thereof, or at least one non-rare earth metal dopant comprising zirconium or oxides thereof. Also included is a quantum memory including: at least one doped polycrystalline ceramic optical device with the ceramic waveguide and a method of fabricating the ceramic waveguide.

The electrolyte membrane of the present disclosure includes a plurality of crystal domains. At least one of the crystal domains includes a first crystal subdomain and a second crystal subdomain. Each of the first crystal subdomain and the second crystal subdomain includes Ba, Zr, M, and O. M is a trivalent element. The concentration of M in the first crystal subdomain is different from the concentration of M in the second crystal subdomain.

An optical component includes an optical device comprising a bonding face and an optically polished end face, and a metal film formed on the bonding face of the optical device and for bonding the optical device onto a substrate. The metal film includes a main covering portion covering a region except an end part of the bonding face on the side of the end face and an end part-covering portion covering the bonding face in the end part. A non-covered part, which is not covered by the metal film, is provided between the main covering portion and end part-covering portion.

The present invention is a thermoplastic polymer composition which contains 10-120 parts by mass of a polar group-containing polypropylene resin (B) per 100 parts by mass of a thermoplastic elastomer (A) that is a block copolymer having a polymer block containing an aromatic vinyl compound unit and a polymer block composed of a conjugated diene unit having 40% by mole or more of 1,2-bonds and 3,4-bonds in total, or a hydrogenated product of the block copolymer (provided that a thermoplastic polymer composition containing 1 part by mass or more of a polyvinyl acetal resin is excluded). This thermoplastic polymer composition is able to be bonded with a ceramic, a metal or a synthetic resin without requiring a primer treatment, and has excellent flexibility, mechanical characteristics, moldability, heat resistance and storage stability.