A new cup-type grinding wheel of the brazed monolayer diamond is developed with a defined grain pattern on the wheel surface. Grinding performance of the brazed wheel in the surface grinding of cemented carbide is stu...A new cup-type grinding wheel of the brazed monolayer diamond is developed with a defined grain pattern on the wheel surface. Grinding performance of the brazed wheel in the surface grinding of cemented carbide is studied. Experimental results show that when continuous dry grinding is employed, grits of the brazed diamond grinding wheel fail mainly in attritious wear and fracture modes and no pull-out ones are found in conventional electroplated and sintered diamond wheels. It indicates the strong retention of brazing alloy to diamond grits and the longer service life of the wheel. In addition, the ground surface has good roughness. The theoretical surface roughness agrees well with experimental results.展开更多
We derive the exchange currents of pseudoscalar, vector, and scalar mesons from Feynman diagrams, and use them to calculate the magnetic form factors of nucleon and △(1232). The magnetic moments and electromagnetic r...We derive the exchange currents of pseudoscalar, vector, and scalar mesons from Feynman diagrams, and use them to calculate the magnetic form factors of nucleon and △(1232). The magnetic moments and electromagnetic radii are obtained by using those form factors and the parameters determined from the masses of nucleon and △(1232).We find the magnetic moments and electromagnetic radii of nucleon and △(1232) can be produced very well in the extended Goldstone-Boson-exchange model in which all of pseudoscalar, vector, and scalar meson nonet are included.The magnetic moments of △(1232) are closer to experiment values and results from lattice calculation than the results obtained by the model without other mesons except for pion and sigma.展开更多
The sources of large and unique platinum-metal placers were the zonal alkali-ultrabasic massifs be- coming active in the Cretaceous time that gravitated to the periphery of the areal of the North-Asian Superplume （NA...The sources of large and unique platinum-metal placers were the zonal alkali-ultrabasic massifs be- coming active in the Cretaceous time that gravitated to the periphery of the areal of the North-Asian Superplume （NAS） influence. Origin of the conditions favorable for the formation of the placer platinum presence in the re- gion is governed by the plume ore-generating magmatism of several generations （ in Proterozoie and Phanerozo- ic）. Ultramafite-mafite magmatism was responsible for the origin of the stratified zonal massifs subjected in the Late Paleozoic and Mesozoic to the action of granitogene derivations of the NAS. The latter provided the devel- opment of the ore-forming magmagene-fluid-metasomatic processes and favorable conditions for the platinum group elements concentration.展开更多
文摘A new cup-type grinding wheel of the brazed monolayer diamond is developed with a defined grain pattern on the wheel surface. Grinding performance of the brazed wheel in the surface grinding of cemented carbide is studied. Experimental results show that when continuous dry grinding is employed, grits of the brazed diamond grinding wheel fail mainly in attritious wear and fracture modes and no pull-out ones are found in conventional electroplated and sintered diamond wheels. It indicates the strong retention of brazing alloy to diamond grits and the longer service life of the wheel. In addition, the ground surface has good roughness. The theoretical surface roughness agrees well with experimental results.
文摘We derive the exchange currents of pseudoscalar, vector, and scalar mesons from Feynman diagrams, and use them to calculate the magnetic form factors of nucleon and △(1232). The magnetic moments and electromagnetic radii are obtained by using those form factors and the parameters determined from the masses of nucleon and △(1232).We find the magnetic moments and electromagnetic radii of nucleon and △(1232) can be produced very well in the extended Goldstone-Boson-exchange model in which all of pseudoscalar, vector, and scalar meson nonet are included.The magnetic moments of △(1232) are closer to experiment values and results from lattice calculation than the results obtained by the model without other mesons except for pion and sigma.
文摘The sources of large and unique platinum-metal placers were the zonal alkali-ultrabasic massifs be- coming active in the Cretaceous time that gravitated to the periphery of the areal of the North-Asian Superplume （NAS） influence. Origin of the conditions favorable for the formation of the placer platinum presence in the re- gion is governed by the plume ore-generating magmatism of several generations （ in Proterozoie and Phanerozo- ic）. Ultramafite-mafite magmatism was responsible for the origin of the stratified zonal massifs subjected in the Late Paleozoic and Mesozoic to the action of granitogene derivations of the NAS. The latter provided the devel- opment of the ore-forming magmagene-fluid-metasomatic processes and favorable conditions for the platinum group elements concentration.
