Abstract: Naphthotriazole derivatives represented by the following general formula (1), wherein, Ar1 is an aromatic hydrocarbon group or an aromatic heterocyclic group, and A is a group that contains an aromatic heterocyclic group. The compound features excellent electron injection/transporting capability, a high hole-blocking power and a high stability in the form of a thin film, and can be used as a material for producing highly efficient and highly durable organic electroluminescent devices.

Abstract: Naphthotriazole derivatives represented by the following general formula (1), wherein, Ar1 is an aromatic hydrocarbon group or an aromatic heterocyclic group, and A is a group that contains an aromatic heterocyclic group. The compound features excellent electron injection/transporting capability, a high hole-blocking power and a high stability in the form of a thin film, and can be used as a material for producing highly efficient and highly durable organic electroluminescent devices.

Abstract: There is provided an organic compound of excellent characteristics that exhibits excellent hole-injecting/transporting performance and has an electron blocking ability and a highly stable thin-film state with excellent heat resistance. The compound of the present invention is an arylamine compound having a triphenylamine structure. The arylamine compound is used as a constituent material of at least one organic layer in an organic electroluminescent device that includes a pair of electrodes, and one or more organic layers sandwiched between the pair of electrodes.

Abstract: A brake drum which can improve the drag strength, strength and rigidity in the diametrical direction, joint strength, and heat radiating ability, that is, a brake drum which is used for a drum brake, wherein the drum has a plurality of the projections at the outer circumferential surface, the plurality of the projections are formed at the outer circumferential surface as a whole when casting a brake drum, and at least part of the projections have thin-waisted shapes. A height of the projections is 0.3 to 5.0 mm, while the number of projections is 5 to 100/cm2. The brake drum is produced by centrifugal casting.

Abstract: There is provided an organic compound of excellent characteristics that exhibits excellent hole-injecting/transporting performance and has an electron blocking ability and a highly stable thin-film state with excellent heat resistance. The compound of the present invention is an arylamine compound having a triphenylamine structure. The arylamine compound is used as a constituent material of at least one organic layer in an organic electroluminescent device that includes a pair of electrodes, and one or more organic layers sandwiched between the pair of electrodes.

Abstract: A brake drum which can improve the drag strength, strength and rigidity in the diametrical direction, joint strength, and heat radiating ability, that is, a brake drum which is used for a drum brake, wherein the drum has a plurality of the projections at the outer circumferential surface, the plurality of the projections are formed at the outer circumferential surface as a whole when casting a brake drum, and at least part of the projections have thin-waisted shapes. A height of the projections is 0.3 to 5.0 mm, while the number of projections is 5 to 100/cm2. The brake drum is produced by centrifugal casting.