Provided are a sodium ion-conductive crystal-containing solid electrolyte sheet capable of giving excellent battery characteristics even when reduced in thickness, and an all-solid-state battery using the same. The solid electrolyte sheet contains at least one type of sodium ion-conductive crystal selected from β″-alumina and NASICON crystal and has a thickness of 500 μm or less and a flatness of 200 μm or less.

A film-forming material of the present invention contains an oxyfluoride of yttrium represented by YOF.sub.Y (X and Y are numbers satisfying 0<X and X<Y) and YF.sub.3, wherein a ratio I.sub.2/I.sub.1 of a peak height I.sub.2 of the (020) plane of YF.sub.3 to a peak height I.sub.1 of the main peak of YO.sub.XF.sub.Y as analyzed by XRD is from 0.005 to 100. It is preferable that a ratio I.sub.4/I.sub.1 of a peak height I.sub.4 of the main peak of Y.sub.2O.sub.3 to the peak height I.sub.1 of the main peak of YO.sub.XF.sub.Y as analyzed by XRD is 0.01 or less.

A film-forming material of the present invention contains an oxyfluoride of yttrium represented by YOF.sub.Y (X and Y are numbers satisfying 0<X and X<Y) and YF.sub.3, wherein a ratio I.sub.2/I.sub.1 of a peak height I.sub.2 of the (020) plane of YF.sub.3 to a peak height I.sub.1 of the main peak of YO.sub.XF.sub.Y as analyzed by XRD is from 0.005 to 100. It is preferable that a ratio I.sub.4/I.sub.1 of a peak height I.sub.4 of the main peak of Y.sub.2O.sub.3 to the peak height I.sub.1 of the main peak of YO.sub.XF.sub.Y as analyzed by XRD is 0.01 or less.

A microsphere of oxide has an opening on its surface connected to a hollow core inside, forming a cavity. The oxide the microsphere is made of is selected from the group consisting of alumina, silica, zirconia, magnesium oxide, calcium oxide and titania. The microsphere of oxide shows better mass and heat transfer characteristics, and has strength significantly higher than that of existing products with similar structures. A FT synthesis catalyst has the microsphere of oxide as a support and an active metal component disposed on the support. The active metal component is one or more selected from the group consisting of Co, Fe, and Ru.

In a first embodiment, a coal treatment process includes exposing a material comprising coal to ionic liquid(s) to form a first mixture, isolating a residue from the first mixture, forming a second mixture comprising the residue, and electrospinning the second mixture to form a carbon fiber precursor material. In a second embodiment, a coal treatment process includes exposing a material comprising coal to ionic liquid(s) to form a mixture comprising solids and a liquid fraction, separating and filtering the liquid fraction from the mixture, and isolating one or more compounds from the liquid fraction. In a third embodiment, a coal treatment process includes exposing a material comprising coal to ionic liquid(s) to form a first mixture comprising residues, exposing the first mixture to (a) an acid, (b) a solvent, or (c) both to form a second mixture, and isolating rare earth elements and rare earth element compounds.

In a first embodiment, a coal treatment process includes exposing a material comprising coal to ionic liquid(s) to form a first mixture, isolating a residue from the first mixture, forming a second mixture comprising the residue, and electrospinning the second mixture to form a carbon fiber precursor material. In a second embodiment, a coal treatment process includes exposing a material comprising coal to ionic liquid(s) to form a mixture comprising solids and a liquid fraction, separating and filtering the liquid fraction from the mixture, and isolating one or more compounds from the liquid fraction. In a third embodiment, a coal treatment process includes exposing a material comprising coal to ionic liquid(s) to form a first mixture comprising residues, exposing the first mixture to (a) an acid, (b) a solvent, or (c) both to form a second mixture, and isolating rare earth elements and rare earth element compounds.

A member for a plasma processing apparatus configured of a tubular body composed of a ceramic having a rare earth element oxide, aluminum oxide, or a rare earth element aluminum composite oxide as a main constituent and including a through hole in an axial direction, in which a number of recessed portions having a depth of from 10 μm to 20 μm, the depth starting from a ridge located between an inner peripheral surface of the tubular body and a target observation surface obtained by polishing from an outer peripheral surface of the tubular body toward an axis, is 2 or less per 1 mm of the ridge.

A member for a plasma processing apparatus configured of a tubular body composed of a ceramic having a rare earth element oxide, aluminum oxide, or a rare earth element aluminum composite oxide as a main constituent and including a through hole in an axial direction, in which a number of recessed portions having a depth of from 10 μm to 20 μm, the depth starting from a ridge located between an inner peripheral surface of the tubular body and a target observation surface obtained by polishing from an outer peripheral surface of the tubular body toward an axis, is 2 or less per 1 mm of the ridge.

Method for producing a photochromic material and a component including the photochromic material, where the method comprises the steps of:-first the formation on a substrate of a layer of an essentially oxygen free metal hydride with a predetermined thickness using a physical vapor deposition process; and -second exposing the metal hydride layer to oxygen where the oxygen reacts with the metal hydride, resulting in a material with photochromic properties.

Method for producing a photochromic material and a component including the photochromic material, where the method comprises the steps of:-first the formation on a substrate of a layer of an essentially oxygen free metal hydride with a predetermined thickness using a physical vapor deposition process; and -second exposing the metal hydride layer to oxygen where the oxygen reacts with the metal hydride, resulting in a material with photochromic properties.