[en] Exposure to oxygen of Fe/MFI catalysts, prepared by sublimation, results in an adsorbed oxygen species capable of reacting with nitrogen oxide or carbon monoxide at room temperature. The IR bands in the perturbed T-O-T vibration region indicate oxidation of Fe²⁺ at room temperature. The FTIR data also show that more nitro groups and nitrate ions are formed from NO+O₂, if Fe/MFI is exposed to oxygen first, than if nitrogen oxide is dosed first. Formation of these NO_y groups is faster on pre-reduced than on pre-oxidized catalysts, which suggests that diatomic oxygen is adsorbed on sites which, in the pre-oxidized catalysts, are occupied by oxide ions. Over pre-reduced catalysts, carbon monoxide oxidation with 18O₂ yields significant amounts of C18O16O and a small amount of C18O₂, even at room temperature.It is uncertain whether the adsorbed diatomic oxygen is present as a superoxide ion, as previously detected by ESR on Fe/MFI, Co/MFI and V/MFI at 77K, or as a peroxo groups bridging over two iron ions, as identified in DFT analysis. Formation of nitrate ions is visualized by interaction of nitrogen oxide with a superoxide ion, possibly via a peroxynitrite ion

[en] The current density J(ρ, z) in a disc-shaped superconducting bulk magnet and the magnetic levitation force F^SBM_z exerted on the superconducting bulk magnet by a cylindrical permanent magnet are calculated from first principles. The effect of the superconducting parameters of the superconducting bulk is taken into account by assuming the voltage-current law E = E_c(J/J_c)ⁿ and the material law B = μ₀H. The magnetic levitation force F^SBM_z is dominated by the remnant current density J'₂(ρ, z), which is induced by switching off the applied magnetizing field. High critical current density and flux creep exponent may increase the magnetic levitation force F^SBM_z. Large volume and high aspect ratio of the superconducting bulk can further enhance the magnetic levitation force F^SBM_z

[en] Efficiency is an important performance indicator of the centrifugal pump, this paper establish three-dimensional model of one high head centrifugal pump in domestic with CFD software, though changing the operating conditions, statistics the calculation efficiency and energy loss under different operating conditions, compare the impact to efficiency and head calculation with steady and unsteady calculation methods, and research the affect when runner in different locations in the centrifugal pump, given and analysis the reasons of the flow field and pressure distribution of runner in different steps.