Abstract: Disclosed is an ultraviolet oxidation device for decompositing organic materials present in water in low energy consumption and low cost, an ultrapure water production device using the same, an ultraviolet oxidation method, and an ultrapure water production method. An ultraviolet oxidation device including: a flow tank 10; photocatalyst fibers 12; an ultraviolet radiating unit 14; and an ultraviolet radiating unit housing unit 16 which is arranged to occupy an entire cross-section of the flow tank intersecting with flowing direction of the water to be processed in the flow tank 10; wherein the ultraviolet radiating unit housing unit 16 is constructed such that the water to he processed flows toward the ultraviolet radiating unit 14 from an upstream side, and after flowing in the housing unit 16, the water to be processed flows out to a downstream side, and is formed of a material that allows the ultraviolet rays from the ultraviolet radiating unit 14 to radiate the photocatalyst fibers 12.

Abstract: Provided are a high-activity photocatalyst fiber and a production method thereof. The photocatalyst fiber is a silica-based composite oxide fiber including a composite oxide phase of an oxide phase (first phase) mainly including a silica component and a metal oxide phase (second phase) including a metal other than silica, in which the ratio of at least one or more metal elements present in a metal oxide constituting the metal oxide phase (second phase) increases gradiently toward the fiber surface, a metal constituting the metal oxide phase (second phase) is formed in the form of particles, mesopores having an average micropore diameter of 2 nm to 30 nm are formed between the particles from the fiber surface toward the inside of the fiber, and platinum (Pt) particles having an average particle diameter of 0.5 nm to 10 nm are supported inside the mesopores.

Abstract: A silica base composite photocatalyst that has appropriate water purification capability, inhibiting precipitation of metal oxides; and a process for producing the same. The silica base composite photocatalyst is one composed mainly of a composite oxide phase consisting of an oxide phase (first phase) composed mainly of silica component and a titania phase (second phase) wherein the ratio of presence of the second phase increases aslope toward the surface layer, characterized in that at least one metal oxide selected from among strontium titanate and barium titanate is contained in the second phase.

Abstract: An object is to provide a silica-based composite oxide fiber which is a continuous fiber high in strength and has, in the fiber surface thereof, mesopores each having an appropriate size, and to provide a catalyst fiber, containing the silica-based composite oxide fiber, in which a noble metal catalyst can be selectively carried into its pores, whereby preventing sintering of the noble metal catalyst.

Abstract: A silica base composite photocatalyst that has appropriate water purification capability, inhibiting precipitation of metal oxides; and a process for producing the same. The silica base composite photocatalyst is one composed mainly of a composite oxide phase consisting of an oxide phase (first phase) composed mainly of silica component and a titania phase (second phase) wherein the ratio of presence of the second phase increases aslope toward the surface layer, characterized in that at least one metal oxide selected from among strontium titanate and barium titanate is contained in the second phase.

Abstract: The present invention is characterized in that a base material is coated with a ceramic thin film comprising a composite phase composed of a first phase mainly formed of a silicon ceramic component and a second phase mainly formed of a ceramic component other than the silicon ceramic component of the first phase, in which the amount of fine crystal particles of at least one ceramic component that constitutes the second phase slopingly increases toward a surface layer. According to the present invention, there are provided a ceramic thin film coating material having a slope constitution, which not only has an excellent function such as a photocatalyst function, an electrical function, a thermal catalyst function or a catalyst-supporting function or environment resistance such as oxidation resistance, alkaline resistance or wear resistance but also has excellent dynamic properties, and a process for the production thereof.

Abstract: The present invention is characterized in that a base material is coated with a ceramic thin film comprising a composite phase composed of a first phase mainly formed of a silicon ceramic component and a second phase mainly formed of a ceramic component other than the silicon ceramic component of the first phase, in which the amount of fine crystal particles of at least one ceramic component that constitutes the second phase slopingly increases toward a surface layer. According to the present invention, there are provided a ceramic thin film coating material having a slope constitution, which not only has an excellent function such as a photocatalyst function, an electrical function, a thermal catalyst function or a catalyst-supporting function or environment resistance such as oxidation resistance, alkaline resistance or wear resistance but also has excellent dynamic properties, and a process for the production thereof.

Abstract: The present invention is characterized in that a base material is coated with a ceramic thin film comprising a composite phase composed of a first phase mainly formed of a silicon ceramic component and a second phase mainly formed of a ceramic component other than the silicon ceramic component of the first phase, in which the amount of fine crystal particles of at least one ceramic component that constitutes the second phase slopingly increases toward a surface layer. According to the present invention, there are provided a ceramic thin film coating material having a slope constitution, which not only has an excellent function such as a photocatalyst function, an electrical function, a thermal catalyst function or a catalyst-supporting function or environment resistance such as oxidation resistance, alkaline resistance or wear resistance but also has excellent dynamic properties, and a process for the production thereof.

Abstract: There are provided a high-strength zirconia-containing inorganic fiber having excellent alkali resistance, oxidation resistance, catalyst function and/or catalyst-carrying function and a process for the production thereof. The zirconia-containing inorganic fiber is a fiber which is formed of a composite oxide phase comprising a first phase mainly formed of a silica component or silicon carbide and a second phase formed of zirconia, and it is characterized in that the ratio of Zr slopingly increases toward the surface layer of the fiber.

Abstract: There are provided a high-strength zirconia-containing inorganic fiber having excellent alkali resistance, oxidation resistance, catalyst function and/or catalyst-carrying function and a process for the production thereof. The zirconia-containing inorganic fiber is a fiber which is formed of a composite oxide phase comprising a first phase mainly formed of a silica component or silicon carbide and a second phase formed of zirconia, and it is characterized in that the ratio of Zr slopingly increases toward the surface layer of the fiber.

Abstract: A silicon-carbide-based inorganic fiber not only excellent in mechanical properties but also excellent in alkali durability and heat resistance, containing at least 0.1% by weight of a metal atom which is at least one member selected from the group consisting of metals belonging to Groups 2A, 3A and 3B of the periodic table and whose oxide exhibits amphoterism or basicity, having an oxygen content of 17% by weight or less, having an atomic ratio of carbon to silicon (C/Si) in the range of from 1 to 1.7, and having a density of less than 2.7 g/cm.sup.3.