A radio wave absorber includes a base member, and a radio wave absorption film formed on the base member. The radio wave absorption film includes at least MTC-substituted ε-Fe.sub.2O.sub.3 and black titanium oxide. The MTC-substituted ε-Fe.sub.2O.sub.3 is a crystal belonging to the same space group as an ε-Fe.sub.2O.sub.3 crystal and expressed by ε-M.sub.xTi.sub.yCo.sub.yFe.sub.2−2y−xO.sub.3 where M is at least one element selected from the group consisting of Ga, In, Al, and Rh, 0<x<1, and 0<y<1.

The present invention relates to a method for producing potassium titanate, and the present invention provides a method for producing potassium titanate which uses anatase-phased titanium dioxide to simplify the process by a hydrothermal method, and thus may improve economical efficiency and productivity, and in which the reaction temperature, the reaction time and the molar ratio of a precursor may be controlled to produce a high-purity potassium titanate whisker having a nano size of an uniform shape.

A polycrystalline YAG sintered body, wherein, when dimensions of a smallest rectangular solid surrounding a YAG sintered body are A mm×B mm×C mm, a maximum value (A, B, C) is 150 mm or less, a minimum value (A, B, C) is more than 20 mm and 40 mm or less, and an optical loss coefficient when light of a wavelength of 300 to 1500 nm (excluding wavelengths which result in absorption of light by an additive element) is transmitted therethrough is 0.002 cm.sup.−1 or less. Moreover, a polycrystalline YAG sintered body, wherein, when dimensions of a smallest rectangular solid surrounding a YAG sintered body are A mm×B mm×C mm, a maximum value (A, B, C) is more than 150 mm and 300 mm or less, a minimum value (A, B, C) is more than 5 mm and 40 mm or less, and an optical loss coefficient when light of a wavelength of 300 to 1500 nm (excluding wavelengths which result in absorption of light by an additive element) is transmitted therethrough is 0.002 cm.sup.−1 or less. An object of an embodiment of the present invention is to provide a large and transparent polycrystalline YAG sintered body and its production method.

The present disclosure relates to a molecular sieve, preparation thereof and acoustic absorption material and speaker containing the same. The molecular sieve having an MFI-structure, comprising a framework and an off-framework cation, wherein the framework comprises SiO.sub.2 and a metal oxide M.sub.xO.sub.y with M comprising boron, gallium or aluminium; the off-framework cation is at least one of hydrogen ion, alkali metal ion and alkaline earth metal ion. The molecular herein can effectively prevent the failure of the molecular sieve and improve the performance stability of the speaker.

A powder mixture of a magnetoplumbite-type hexagonal ferrite is a mixture of powders of two or more kinds of compounds represented by Formula (1), the two or more kinds of compounds represented by Formula (1) are two or more kinds of compounds having different values of x in Formula (1), and are a powder mixture satisfying a relationship of x.sub.max-x.sub.min23 0.2, in a case where a maximum value of x is defined as x.sub.max and a minimum value of x is defined as x.sub.min, in two or more kinds of compounds having different values of x in Formula (1), and the application. In Formula (1), A represents at least one metal element selected from the group consisting of Sr, Ba, Ca, and Pb, and x satisfies 1.5≤x≤8.0.

AFe.sub.(12-x) Al.sub.xO.sub.19   Formula (1)

The present disclosure relates to methods of preparing sols of titanium dioxide nanoparticles that are photoactive, neutral, and in a substantially concentrated form. The methods particularly provide for concentrated sols in light of washing and dewatering under low cation concentrations and utilizing rapid peptizing through addition of the filter case to the peptizing agent. Concentrated acid may be utilized to maintain high TiO.sub.2 concentration while still avoiding precipitation of the colloidal TiO.sub.2. Concentrated photoactive, neutral titanium dioxide sols are also provided as well as compositions thereof and photoactive coatings formed therewith.

A powder of melted particles, more than 95% by number of the particles exhibiting a circularity of greater than or equal to 0.85. The powder including more than 99.8% of a rare earth metal oxide and/or of hafnium oxide and/or of an aluminum oxide, as percentage by mass based on the oxides. The powder has a median particle size D.sub.50 of less than 15 μm, a 90 percentile of the particle sizes, D.sub.90, of less than 30 μm, and a size dispersion index (D.sub.90−D.sub.10)/D.sub.10 of less than 2, and a relative density of greater than 90%. The D.sub.n percentiles of the powder are the particle sizes corresponding to the percentages, by number, of n%, on the cumulative distribution curve of the size of the particles in the powder and the particle sizes are classified by increasing order.

A solid-state electrolyte having a garnet-type crystal structure represented by the formula (Li.sub.7−ax+yA.sub.x)La.sub.3(Zr.sub.2−yB.sub.y)O.sub.12, where A is at least one element selected from Mg, Zn, Al, Ga, and Sc, a is a valence of A, B is at least one element selected from Al, Ga, Sc, Yb, Dy, and Y, x is more than 0 and less than 1.0, y is more than 0 and less than 1.0, and 7−ax+y is more than 5.5 and less than 7.0).

A compound represented by the Formula 1 and having an argyrodite-type crystal structure:

Li.sub.aM1.sub.xM2.sub.wPS.sub.yM3.sub.z  Formula 1

wherein M1 is at least one element of Group 2 or Group 11 of the periodic table, M2 is at least one metal element other than Li of Group 1 of the periodic table, M3 is at least one element of Group 17 of the periodic table, and wherein 4≤a≤8, 0<x<0.5, 0≤w<0.5, 3≤y≤7, and 0≤z≤2.

A method of manufacturing a high-ion conductive sulfide-based solid electrolyte using dissolution-precipitation includes preparing a composite solvent including a first solvent including a cyano group and a second solvent having a polarity index of less than 4, introducing a raw material including lithium sulfide (Li.sub.2S) and phosphorus pentasulfide (P.sub.2S.sub.5) into the composite solvent, and stirring the raw material to obtain a sulfide precipitate.