Abstract: A thermoelectric conversion module includes a base material having heat insulation properties and carbon nanotube yarn that is helically wound around the base material, P-type parts and N-type parts are alternately arranged and are series-connected in an extension direction of the carbon nanotube yarn, one side part of a helix formed by the carbon nanotube yarn is formed as a heat reception part, and the other side part across the base material from the one side part is formed as a heat dissipation part, lengths of the P-type parts and lengths of the N-type parts are shorter than a length of a one-turn portion of the helix, and the P-type parts and the N-type parts are arranged such that respective one end parts are included in the heat reception part and respective other end parts are included in the heat dissipation part.

Abstract: Applicability to a composite material with high purity and high strength, and a material requiring high conductivity or high thermal conductivity is enhanced. The present invention relates to a multi-walled carbon nanotube having two or more tubes of a graphene sheet where carbon atoms are arranged in a hexagonal honeycomb form, coaxially, wherein a diameter of an outermost wall based on observation of an image by a transmission electron microscope is 3 nm or more and 15 nm or less, and a length based on observation of an image of a scanning electron microscope is 1.0 mm or more, an aggregate of multi-walled carbon nanotubes and a method for preparing the multi-walled carbon nanotube.

Abstract: Applicability to a composite material with high purity and high strength, and a material requiring high conductivity or high thermal conductivity is enhanced. The present invention relates to a multi-walled carbon nanotube having two or more tubes of a graphene sheet where carbon atoms are arranged in a hexagonal honeycomb form, coaxially, wherein a diameter of an outermost wall based on observation of an image by a transmission electron microscope is 3 nm or more and 15 nm or less, and a length based on observation of an image of a scanning electron microscope is 1.0 mm or more, an aggregate of multi-walled carbon nanotubes and a method for preparing the multi-walled carbon nanotube.