We studied the electronic structure of the two new transition-metal carbodiimides CoNCN and NiNCN using first-principles method, which is based on density-functional theory （DFT）. The density of states （DOS）, the ...We studied the electronic structure of the two new transition-metal carbodiimides CoNCN and NiNCN using first-principles method, which is based on density-functional theory （DFT）. The density of states （DOS）, the total energy of the cell and the spin magnetic moment of CoNCN and NiNCN were calculated. The calculations reveal that the compound CoNCN and NiNCN have hall-metallic properties in ferromagnetic ground state, and the spin magnetic moment per molecule is about 7.000 μB and 6.000 μB for CoNCN and NiNCN, respectively.展开更多
The Kapchinsky Vladimirsky(K-V)beam through a hackle periodic-focusing magnetic field is studiedusing the particle-core model.The beam halo-chaos is found,and an idea of fraction power-law function controller ispropos...The Kapchinsky Vladimirsky(K-V)beam through a hackle periodic-focusing magnetic field is studiedusing the particle-core model.The beam halo-chaos is found,and an idea of fraction power-law function controller isproposed based on the mechanism of halo formation and the strategy of controlling halo-chaos.The method is appliedto the multi-particle simulation to control the halo.The numerical results show that the halo-chaos and its regenerationcan be eliminated effectively by using the fraction power-law function control method.At the same time,the radialparticle density is uniform at the beam's center as long as the control method and appropriate parameter are chosen.展开更多
The temperature and angle dependent resistivity of Ba(Fe 0.75 Ru 0.25) 2 As 2 single crystals were measured in magnetic fields up to 14 T.The temperature dependent resistivity with the magnetic field aligned parallel ...The temperature and angle dependent resistivity of Ba(Fe 0.75 Ru 0.25) 2 As 2 single crystals were measured in magnetic fields up to 14 T.The temperature dependent resistivity with the magnetic field aligned parallel to c-axis and ab-planes allow us to derive the slope of dH ab c2 /dT and dH c c2 /dT near T c yielding an anisotropy ratio Γ = dH ab c2 /dT/dH c c2 /dT ≈ 2.By scaling the curves of resistivity vs.angle measured at a fixed temperature but different magnetic fields within the framework of the anisotropic Ginzburg-Landau theory,we obtained the anisotropy in an alternative way.Again we found that the anisotropy(m c /m ab) 1/2 was close to 2.This value is similar to that in Ba0.6K0.4Fe2As2(K-doped Ba122) and Ba(Fe 0.92 Co 0.08) 2 As 2(Co-doped Ba122).This suggests that the 3D warping effect of the Fermi surface in Ru-doped samples may not be stronger than that in the K-doped or Co-doped Ba122 samples,therefore the possible nodes appearing in Ru-doped samples cannot be ascribed to the 3D warping effect of the Fermi surface.展开更多
文摘We studied the electronic structure of the two new transition-metal carbodiimides CoNCN and NiNCN using first-principles method, which is based on density-functional theory （DFT）. The density of states （DOS）, the total energy of the cell and the spin magnetic moment of CoNCN and NiNCN were calculated. The calculations reveal that the compound CoNCN and NiNCN have hall-metallic properties in ferromagnetic ground state, and the spin magnetic moment per molecule is about 7.000 μB and 6.000 μB for CoNCN and NiNCN, respectively.
基金National Natural Science Foundation of China under Crant No.10247005the Natural Science Foundation of the Anhui Higher Education Institutions of China under Grant No.KJ2007B187the Scientific Research Foundation of China University Of Mining and Technology for the Young under Grant No.OK060119
文摘The Kapchinsky Vladimirsky(K-V)beam through a hackle periodic-focusing magnetic field is studiedusing the particle-core model.The beam halo-chaos is found,and an idea of fraction power-law function controller isproposed based on the mechanism of halo formation and the strategy of controlling halo-chaos.The method is appliedto the multi-particle simulation to control the halo.The numerical results show that the halo-chaos and its regenerationcan be eliminated effectively by using the fraction power-law function control method.At the same time,the radialparticle density is uniform at the beam's center as long as the control method and appropriate parameter are chosen.
基金supported by the National Natural Science Foundation of China (Grant No. 11034011/A0402)the National Basic Research Program of China (Grant Nos. 2011CBA00102 and 2012CB821403)PAPD
文摘The temperature and angle dependent resistivity of Ba(Fe 0.75 Ru 0.25) 2 As 2 single crystals were measured in magnetic fields up to 14 T.The temperature dependent resistivity with the magnetic field aligned parallel to c-axis and ab-planes allow us to derive the slope of dH ab c2 /dT and dH c c2 /dT near T c yielding an anisotropy ratio Γ = dH ab c2 /dT/dH c c2 /dT ≈ 2.By scaling the curves of resistivity vs.angle measured at a fixed temperature but different magnetic fields within the framework of the anisotropic Ginzburg-Landau theory,we obtained the anisotropy in an alternative way.Again we found that the anisotropy(m c /m ab) 1/2 was close to 2.This value is similar to that in Ba0.6K0.4Fe2As2(K-doped Ba122) and Ba(Fe 0.92 Co 0.08) 2 As 2(Co-doped Ba122).This suggests that the 3D warping effect of the Fermi surface in Ru-doped samples may not be stronger than that in the K-doped or Co-doped Ba122 samples,therefore the possible nodes appearing in Ru-doped samples cannot be ascribed to the 3D warping effect of the Fermi surface.
