Abstract: A method for producing a carbon fiber includes a separation step of separating an ash-free coal obtained from a bituminous coal or a sub-bituminous coal, into a soluble component(s) and an insoluble component(s) by a solvent extraction treatment, a heat treatment step of heat-treating the soluble component(s), a melt spinning step of melt-spinning the soluble component(s) subjected to the heat treatment, an infusibilization step of infusibilizing a filament body obtained by the melt spinning, and a carbonization step of carbonizing the filament body subjected to the infusibilization.

Abstract: There is provided a negative-electrode material for rechargeable batteries with a nonaqueous electrolyte which have a high charge/discharge capacity and excellent rate characteristics. The negative-electrode material for rechargeable batteries with a nonaqueous electrolyte comprises: carbon material having a carbon atom content of not less than 98.0% in terms of mass and a lattice spacing (d002) of not more than 3.370 angstroms in the C-axis direction; and a boron compound represented by general formula HxBOy wherein x represents a real number of 0 to 1.0; and y represents a real number of 1.5 to 3.0, wherein the boron compound is bonded to a portion of the carbon atoms of the carbon material.

Abstract: A carbon nanohorn carried material for producing a carbon nanotube by a chemical vapor deposition (CVD) method, including a catalytic metal or a compound thereof contained inside carbon nanohorns or supported on exterior walls of the carbon nanohorns is provided. A carbon nanotube is produced by a CVD reaction using the carbon nanohorn carried material. A novel technical means for producing a carbon nanotube which does not use any noncarbon type carrier, can easily collect and purify the carbon nanotube and can control the length of the carbon nanotube can be provided.

Abstract: A carbon nanohorn carried material for producing a carbon nanotube by a chemical vapor deposition (CVD) method, including a catalytic metal or a compound thereof contained inside carbon nanohorns or supported on exterior walls of the carbon nanohorns is provided. A carbon nanotube is produced by a CVD reaction using the carbon nanohorn carried material. A novel technical means for producing a carbon nanotube which does not use any noncarbon type carrier, can easily collect and purify the carbon nanotube and can control the length of the carbon nanotube can be provided.

Abstract: A contrast agent characterized in that each of carbon nanohorns forming a carbon nanohorn aggregate has an opening at the side wall or tip, wherein a metal M (at least one metal selected from among paramagnetic metals, ferromagnetic metals, and superparamagnetic metals) or a compound of the metal M is incorporated in or dispersed on each of the carbon nanohorns. A contrast agent characterized in that it contains a Gd oxide. There is provided a contrast agent, which can be mass-produced easily, and satisfies the requirement of low toxicity and enables microscopic diagnoses when used for MRI. A contrast agent characterized in that is contains a carbon nanohorn aggregate.

Abstract: A carbon nanohorn carried material for producing a carbon nanotube by a chemical vapor deposition (CVD) method, including a catalytic metal or a compound thereof contained inside carbon nanohorns or supported on exterior walls of the carbon nanohorns is provided. A carbon nanotube is produced by a CVD reaction using the carbon nanohorn carried material. A novel technical means for producing a carbon nanotube which does not use any noncarbon type carrier, can easily collect and purify the carbon nanotube and can control the length of the carbon nanotube can be provided.

Abstract: A contrast agent characterized in that each of carbon nanohorns forming a carbon nanohorn aggregate has an opening at the side wall or tip, wherein a metal M (at least one metal selected from among paramagnetic metals, ferromagnetic metals, and superparamagnetic metals) or a compound of the metal M is incorporated in or dispersed on each of the carbon nanohorns. A contrast agent characterized in that it contains a Gd oxide. There is provided a contrast agent, which can be mass-produced easily, and satisfies the requirement of low toxicity and enables microscopic diagnoses when used for MRI. A contrast agent characterized in that is contains a carbon nanohorn aggregate.