Abstract: A fine carbon fiber having an outer diameter of about 1 to about 80 nm and an aspect ratio of 10 to 30,000, comprising a hollow center portion and a multi-layer sheath structure of a plurality of carbon layers, the layers forming annual rings, wherein the sheath-forming carbon layers form an incomplete sheath, i.e., the carbon layers are partially broken or disrupted in a longitudinal direction, and the outer diameter of the carbon fiber and/or the diameter of the hollow center portion are not uniform in a longitudinal direction. The carbon fiber is obtained by instantaneously reacting a carrier gas at a high temperature and an organic compound gas kept at a temperature below the decomposition temperature of the transition metal compound and has a conductivity equivalent to that of a conventional vapor phase method and is useful as a filler material in resins, rubbers, paints and the like.

Abstract: A fine carbon fiber having a multilayer structure having stacked cylindrical carbon sheets and a center axis having a hollow structure. The fine carbon fiber has an outer diameter of 2 to 300 nm and an aspect ratio of 10 to 15,000, and at least one cylindrical carbon sheet layer among the multiple layers is folded at an end part of the carbon fiber and continued to another cylindrical carbon sheet. The folded and continued cylindrical carbon sheets form a cylindrical structure opened at the end part.

Abstract: A fine carbon fiber mixture produced through a vapor-growth process, which comprises fine carbon fiber, each fiber filament of the fiber having an outer diameter of 1 to 500 nm and an aspect ratio of 10 to 15,000 and comprising a hollow space extending along its center axis and a multi-layer sheath structure consisting of a plurality of carbon layers; and non-fibrous carbon such as flake-like carbon, granular carbon, or sheet-like carbon. A composition comprising a resin or a rubber and a fine carbon fiber mixture as above contained therein. An electrically conductive article or a sliding article comprising the composition.

Abstract: A high-sensitivity measuring instrument comprising at least two sensors for detecting the same characteristics by touching a substance being measured with a specified time difference, wherein the between detection signals taken out simultaneously from respective sensors is determined, the difference between characteristic values upon elapsing the specified time difference is determined from the difference between detection signals, a reference time of measurement and a reference characteristic value at that time are preset, a time axis having a time pitch of a specified time difference is set, and a measurement value is obtained at a point in time elapsing an arbitrary time pitch from the reference time. Objective measurement characteristics can be detected by the measuring instrument not in the form of difference or variation but as an absolute value with high accuracy and sensitivity.

Abstract: A fine carbon fiber, the main body of each fiber filament of the fiber having an outer diameter of about 1 to about 500 nm and an aspect ratio of about 10 to about 15,000 and comprising a hollow space extending along its center axis and a multi-layer sheath structure consisting of a plurality of carbon layers, the layers forming concentric rings, wherein the fiber filament has a nodular portion which is formed of outwardly protruding carbon layers or formed of a locally increased number of carbon layers. A similar fine carbon fiber, in which the fiber filament has repeatedly enlarged protruding portions and the filament diameter varies along with the length of the filament, the ratio of the diameter (d?) of a fiber filament of the fiber as measured at the outwardly enlarged portions to the diameter (d) of a fiber filament of the fiber as measured at a position at which no outwardly enlarged portions is present; i.e., d?/d, being about 1.05 to about 3, is also provided.

Abstract: A fine carbon fiber mixture produced through a vapor-growth process, which comprises fine carbon fiber, each fiber filament of the fiber having an outer diameter of 1 to 500 nm and an aspect ratio of 10 to 15,000 and comprising a hollow space extending along its center axis and a multi-layer sheath structure consisting of a plurality of carbon layers; and non-fibrous carbon such as flake-like carbon, granular carbon, or sheet-like carbon. A composition comprising a resin or a rubber and a fine carbon fiber mixture as above contained therein. An electrically conductive article or a sliding article comprising the composition.

Abstract: An abrasive composite material containing a matrix, abrasive grains, and carbon fiber having a multi-layer structure, each fiber filament of the carbon fiber having an outer diameter of about 2 to about 500 nm and an aspect ratio of about 5 to about 15,000, and including a hollow space extending along its center axis. Preferably, the carbon fiber has a BET specific surface area of about 4 m2/g or more; the carbon fiber has, at a carbon (002) plane, an interlayer distance (d002) of about 0.345 nm or less as measured by means of X-ray diffractometry; and the ratio of the peak height (Id) of the band at 1,341 to 1,349 cm−1 in a Raman scattering spectrum of the carbon fiber to the peak height (Ig) of the band at 1,570 to 1,578 cm−1 in the spectrum; i.e., Id/Ig, is about 1.5 or less. More preferably, the carbon fiber contains branched vapor grown carbon fiber; boron is contained, in an amount of about 0.

Abstract: Oxygen is mixed with heater drain water of power plant which contains fine particles of iron oxides such that the concentration of the dissolved oxygen in the heater drain water after the mixing of oxygen is in a range from 1 &mgr;g/liter to 20 &mgr;g/liter. The obtained heater drain water after oxygen mixing is filtered through a filter such as a hollow fiber filter to remove fine particles of iron oxides.

Abstract: A vapor grown fine carbon fiber including a hollow space along the fiber in its interior, and having a multi-layer structure, an outer diameter of 2 to 500 nm, and an aspect ratio of 10 to 15,000 is disclosed. The fiber has a center portion and a peripheral portion, and the center portion having a carbon structure different from that of the peripheral portion. A method for producing the fine carbon fiber, and a battery and gas occlusion material containing the fine carbon fiber are also disclosed.

Abstract: (1) A method for producing vapor grown carbon, comprising mixing a raw material gas containing an organic compound and an organo-transition metallic compound preliminarily heated preferably to a temperature 100 to 145° C. with a carrier gas heated preferably to a temperature 700 to 1,600° C., and introducing the resultant gas mixture into a carbon fiber production zone, wherein preferably a mixture of an aromatic compound and acetylene, ethylene, or butadiene is used as an organic compound; (2) a method in which a transition metallic compound is dissolved in a solvent, the resultant solution is atomized into fine droplets, the solvent in the droplets is evaporated to thereby obtain fine particles of the transition metal compound, the drifting particles are introduced with an organic compound gas into the carbon fiber production zone; (3) an apparatus used in the production methods; and (4) vapor grown carbon fiber thereby produced.

Abstract: A fine carbon fiber having an outer diameter of about 1 to about 80 nm and an aspect ratio of 10 to 30,000, comprising a hollow center portion and a multi-layer sheath structure of a plurality of carbon layers, the layers forming annual rings, wherein the sheath-forming carbon layers form an incomplete sheath, i.e., the carbon layers are partially broken or disrupted in a longitudinal direction, and the outer diameter of the carbon fiber and/or the diameter of the hollow center portion are not uniform in a longitudinal direction. The carbon fiber is obtained by instantaneously reacting a carrier gas at a high temperature and an organic compound gas kept at a temperature below the decomposition temperature of the transition metal compound and has a conductivity equivalent to that of a conventional vapor phase method and is useful as a filler material in resins, rubbers, paints and the like.

Abstract: A vapor grown fine carbon fiber including a hollow space along the fiber in its interior, and having a multi-layer structure, an outer diameter of 2 to 500 nm, and an aspect ratio of 10 to 15,000 is disclosed. The fiber has a center portion and a peripheral portion, and the center portion having a carbon structure different from that of the peripheral portion. A method for producing the fine carbon fiber, and a battery and gas occlusion material containing the fine carbon fiber are also disclosed.

Abstract: A fine carbon fiber having an outer diameter of about 1 to about 80 nm and an aspect ratio of 10 to 30,000, comprising a hollow center portion and a multi-layer sheath structure of a plurality of carbon layers, the layers forming annual rings, wherein the sheath-forming carbon layers form an incomplete sheath, i.e., the carbon layers are partially broken or disrupted in a longitudinal direction, and the outer diameter of the carbon fiber and/or the diameter of the hollow center portion are not uniform in a longitudinal direction. The carbon fiber is obtained by instantaneously reacting a carrier gas at a high temperature and an organic compound gas kept at a temperature below the decomposition temperature of the transition metal compound and has a conductivity equivalent to that of a conventional vapor phase method and is useful as a filler material in resins, rubbers, paints and the like.

Abstract: A branched vapor-grown carbon fiber having an outer diameter of 0.5 &mgr;m or less and an aspect ratio of at least 10, the carbon fiber having a compressed specific resistance of 0.02 &OHgr;·cm or less, each fiber filament having a hollow cylindrical structure, preferably the carbon fiber containing boron and having a compressed specific resistance of 0.018 &OHgr;·cm or less. An electrically conductive transparent composition comprising a resin binder and carbon fiber incorporated into the binder, having transparency and comprising vapor grown carbon fiber having an outer diameter of 0.01-0.1 &mgr;m, an aspect ratio of 10-15,000, and a compressed specific resistance of 0.02 &OHgr;·cm or less, and surface resistivity of 10,000 &OHgr;/□ or less. An electrically conductive transparent material formed from the aforementioned electrically conductive transparent composition.

Abstract: A fine carbon fiber, the main body of each fiber filament of the fiber having an outer diameter of about 1 to about 500 nm and an aspect ratio of about 10 to about 15,000 and comprising a hollow space extending along its center axis and a multi-layer sheath structure consisting of a plurality of carbon layers, the layers forming concentric rings, wherein the fiber filament has a nodular portion which is formed of outwardly protruding carbon layers or formed of a locally increased number of carbon layers. A similar fine carbon fiber, in which the fiber filament has repeatedly enlarged protruding portions and the filament diameter varies along with the length of the filament, the ratio of the diameter (d″) of a fiber filament of the fiber as measured at the outwardly enlarged portions to the diameter (d) of a fiber filament of the fiber as measured at a position at which no outwardly enlarged portions is present; i.e., d″/d, being about 1.05 to about 3, is also provided.

Abstract: A fine carbon fiber having a multilayer structure having stacked cylindrical carbon sheets and a center axis having a hollow structure. The fine carbon fiber has an outer diameter of 2 to 300 nm and an aspect ratio of 10 to 15,000, and at least one cylindrical carbon sheet layer among the multiple layers is folded at an end part of the carbon fiber and continued to another cylindrical carbon sheet. The folded and continued cylindrical carbon sheets form a cylindrical structure opened at the end part.

Abstract: Oxygen is mixed with heater drain water of power plant which contains fine particles of iron oxides such that the concentration of the dissolved oxygen in the heater drain water after the mixing of oxygen is in a range from 1 &mgr;g/liter to 20 &mgr;g/liter. The obtained heater drain water after oxygen mixing is filtered through a filter such as a hollow fiber filter to remove fine particles of iron oxides.

Abstract: A fine carbon fiber having a multilayer structure having stacked cylindrical carbon sheets and a center axis having a hollow structure. The fine carbon fiber has an outer diameter of 2 to 300 nm and an aspect ratio of 10 to 15,000, and at least one cylindrical carbon sheet layer among the multiple layers is folded at an end part of the carbon fiber and continued to another cylindrical carbon sheet. The folded and continued cylindrical carbon sheets form a cylindrical structure opened at the end part.

Abstract: A catalyst composition for a cell comprising catalyst-bearing conductive powder particles and fibrous carbon. A membrane-electrode assembly for a fuel cell comprising an electrolyte membrane and an electrode including a catalyst layer and a gas diffusion layer, the electrode being provided on each surface of the electrolyte membrane, wherein at least a portion of the surface of the gas diffusion layer which is in contact with the catalyst layer includes a layer containing a hydrophobic resin and fibrous carbon.

Abstract: A vapor grown fine carbon fiber including a hollow space along the fiber in its interior, and having a multi-layer structure, an outer diameter of 2 to 500 nm, and an aspect ratio of 10 to 15,000 is disclosed. The fiber has a center portion and a peripheral portion, and the center portion having a carbon structure different from that of the peripheral portion. A method for producing the fine carbon fiber, and a battery and gas occlusion material containing the fine carbon fiber are also disclosed.