Abstract: A method for checking or testing the profile of the path of contact of involute helical cylindrical gears is disclosed. The crossed helical gear transmits motion through the profile of the path of contact, and checking or testing the profile of the path of contact can reflect the transmission quality and working stability of the gear and the actual motion condition. In the gear hobbing, the grinding, the shaving and other generating machining, the movement of tools and gears is achieved based on the profile of the path of contact, and controlling the profile of the path of contact has unique advantages in controlling the quality of gear processing.

Abstract: A reversible enrichment material, its preparation and application thereof are provided. The reversible enrichment material includes an inorganic carrier; and an active metal salt, a first metal salt promoter and a second metal salt promoter supported on the inorganic carrier. The active metal salt is a soluble silver salt, a soluble copper salt, or a combination thereof. The first metal salt promoter is one or more selected from the group consisting of soluble salts of Group IA, Group IIA and Group IIIA metals, and the second metal salt promoter is one or more selected from the group consisting of soluble salts of transition metals other than Group IB metals. The reversible enrichment material can realize effective separation of saturated hydrocarbon from unsaturated hydrocarbon and has good reversibility.

Abstract: A layer I vanadium-doped PIN-type nuclear battery, including from top to bottom a radioisotope source layer(1), a p-type ohm contact electrode(4), a SiO2 passivation layer(2), a SiO2 compact insulation layer(3), a p-type SiC epitaxial layer(5), an n-type SiC epitaxial layer(6), an n-type SiC substrate(7) and an n-type ohm contact electrode(8). The doping density of the p-type SiC epitaxial layer(5) is 1×1019 to 5×1019 cm?3, the doping density of the n-type SiC substrate(7) is 1×1018 to 7×1018 cm?3. The n-type SiC epitaxial layer(6) is a low-doped layer I formed by injecting vanadium ions, with the doping density thereof being 1×1013 to 5×1014 cm?3. Also provided is a preparation method for a layer I vanadium-doped PIN-type nuclear battery. The present invention solves the problem that the doping density of layer I of the exiting SiC PIN-type nuclear battery is high.

Abstract: A layer I vanadium-doped PIN-type nuclear battery, including from top to bottom a radioisotope source layer(1), a p-type ohm contact electrode(4), a SiO2 passivation layer(2), a SiO2 compact insulation layer(3), a p-type SiC epitaxial layer(5), an n-type SiC epitaxial layer(6), an n-type SiC substrate(7) and an n-type ohm contact electrode(8). The doping density of the p-type SiC epitaxial layer(5) is 1×1019 to 5×1019 cm3, the doping density of the n-type SiC substrate(7) is 1×1018 to 7×1018 cm3. The n-type SiC epitaxial layer(6) is a low-doped layer I formed by injecting vanadium ions, with the doping density thereof being 1×1013 to 5×1014 cm3. Also provided is a preparation method for a layer I vanadium-doped PIN-type nuclear battery. The present invention solves the problem that the doping density of layer I of the exiting SiC PIN-type nuclear battery is high.