Abstract: The present invention provides a method for easily producing a gas cylinder which includes a shaped product of carbonaceous gas storage material capable of achieving practical gas storage capacity, which allows full exploitation of excellent gas storage property of the carbonaceous gas storage material, and which has excellent pressure resistance and is expected to be safe. The invention also provides the gas cylinder obtained by the method, and a method for storing/discharging gas using the cylinder, which provides stable storage and discharge of gas at high efficiency.

Abstract: A raw material composite 10 for a carbon material used in an electric double layer capacitor contains microcrystalline carbon having a layered crystal structure similar to graphite, and is formed a carbon material for an electric double layer capacitor by undergoing an activation treatment. Here, the raw material composite is characterized in that a Hardgrove grindability index HGI defined by ASTMD-409-71 is 50 or above, an interlayer distance d002 of the microcrystalline carbon determined by an X-ray diffraction method is 0.343 NM or below, and a crystallite size Lc002 of the microcrystalline carbon determined by the X-ray diffraction method is 3.0 nm or below.

Abstract: A raw material composite 10 for a carbon material used in an electric double layer capacitor contains microcrystalline carbon having a layered crystal structure similar to graphite, and is formed a carbon material for an electric double layer capacitor by undergoing an activation treatment. Here, the raw material composite is characterized in that a Hardgrove grindability index HGI defined by ASTMD-409-71 is 50 or above, an interlayer distance d002 of the microcrystalline carbon determined by an X-ray diffraction method is 0.343 NM or below, and a crystallite size Lc002 of the microcrystalline carbon determined by the X-ray diffraction method is 3.0 nm or below.

Abstract: Carbon fiber including graphitized fiber is processed electrochemically in an acidic solution for a time sufficient to run a layer reaction such that the reaction extends to the inside of the fiber and thereafter, as required, heat-treated accurately at 100° C. or more to expand layer spacing to form multifibrous carbon fiber, with which hydrogen is brought into contact, adsorbing hydrogen in the inside of the multifibrous carbon fiber.

Abstract: Carbon fiber including graphitized fiber is processed electrochemically in an acidic solution for a time sufficient to run a layer reaction such that the reaction extends to the inside of the fiber and thereafter, as required, heat-treated accurately at 100° C. or more to expand layer spacing to form multifibrous carbon fiber, with which hydrogen is brought into contact, adsorbing hydrogen in the inside of the multifibrous carbon fiber.

Abstract: A process for producing a carbon/carbon composite having a ceramic and carbon coating on its surface consists essentially of the steps of heating a carbon/carbon composite at a temperature of from 800.degree. to 1,700.degree. C., contacting the thus heated composite in the presence of hydrogen with at least one compound selected from the group consisting of halides and hydrides of Si, Zr, Ti, Hf, B, Nb and W in gaseous form to convert the surface of the carbon/carbon composite, in the absence of a carbon releasing gas, into a carbide ceramic layer and then forming a coating film consisting of both carbon and ceramic by vapor phase decomposition at a pressure of 5-100 Torr on said carbide ceramic.

Abstract: A carbon material having oxidation resistance is prepared by forming a fi coating constituted mainly by carbon on the surface of a carbon/carbon composite by chemical vapor deposition, then forming on said first coating a second coating of a ceramic or both a ceramic and carbon by chemical vapor deposition, and changing at least one of thermal physical properties or mechanical physical properties of carbon in said first coating continuously or step-wise.