The level structure of the double-magic nucleus ^(34)Si(Z=14,N=20)was investigated by evaluating the available data.On the basis of experimental results from the beta-decay and fusion-evaporation reactions,we establis...The level structure of the double-magic nucleus ^(34)Si(Z=14,N=20)was investigated by evaluating the available data.On the basis of experimental results from the beta-decay and fusion-evaporation reactions,we established the level scheme by assigning spin-parities up to 6_(1)^(+)at 6233 keV.The high energy positions of the excited states are consistent with the magicity at ^(34)Si,such as the 2_(2)^(+)state of the spherical ground band at 4.519 MeV and the 3^(-),4^(-),and 5^(-)states of the one-particle one-hole cross-shell states at approximately 4.5 MeV.This nucleus,for a long time,has attracted much attention because of,on one side,a proton bubble structure in the ground state and,on the other side,a deformation in the second 0^(+)state,0_(2)^(+).By a comparison of the constructed level scheme with the shell model calculations,we describe the emerging structures in the ground and second 0+states and the negative-parity 3^(-)states within the framework of the shell model context.We propose a deformed rotational band with the cascading 6_(2)^(+)−4_(1)^(+)−2_(1)^(+)transitions built on the 0_(2)^(+)state.展开更多
The LBGK(lattice Bhatnagar-Gross-Krook)model of the lattice Boltzmann method including second-order boundary condition treatment for curve geometry was employed to investigate the flow around particle clusters.The dra...The LBGK(lattice Bhatnagar-Gross-Krook)model of the lattice Boltzmann method including second-order boundary condition treatment for curve geometry was employed to investigate the flow around particle clusters.The drag coefficient is a benchmark problem in the analysis of particle-fluid complex systems,especially,in a gas-solid fluidized bed.In the present work,the drag coefficient on a spherical particle in a cluster,was evaluated by using the momentum-exchange method directly.Two different configurations of cluster were measured based on the lattice Boltzmann method.Computational results indicated that the drag coefficient on an individual particle in a cluster depended heavily on the configuration of cluster.And the drag coefficient on the particle in the cluster was lower when that particle was shielded by other particles.Additionally,except for the configuration factor,both the inter-distance and Reynolds number had a strong effect on the drag coefficient on an individual particle as well.It was found that the drag coefficient on each particle varied drastically with clustering.Omitting the effect of clustering might result in incorrect drag forces in the simulation.展开更多
The two-fluid model is widely adopted in simulations of dense gas-particle flows in engineering facili- ties. Present two-phase turbulence models for two-fluid modeling are isotropic. However, turbulence in actual gas...The two-fluid model is widely adopted in simulations of dense gas-particle flows in engineering facili- ties. Present two-phase turbulence models for two-fluid modeling are isotropic. However, turbulence in actual gas-particle flows is not isotropic. Moreover, in these models the two-phase velocity correlation is closed using dimensional analysis, leading to discrepancies between the numerical results, theoretical analysis and experiments. To rectify this problem, some two-phase turbulence models were proposed by the authors and are applied to simulate dense gas-particle flows in downers, risers, and horizontal channels; Experimental results validate the simulation results. Among these models the USM-O and the two-scale USM models are shown to give a better account of both anisotropic particle turbulence and particle-particle collision using the transport equation model for the two-phase velocity correlation.展开更多
基金Supported by the Institute for Basic Science Korea(IBS-R031-D1)Guangdong Major Project of Basic and Applied Basic Research(2021B0301030006)computational resources from Sun Yat-sen University。
文摘The level structure of the double-magic nucleus ^(34)Si(Z=14,N=20)was investigated by evaluating the available data.On the basis of experimental results from the beta-decay and fusion-evaporation reactions,we established the level scheme by assigning spin-parities up to 6_(1)^(+)at 6233 keV.The high energy positions of the excited states are consistent with the magicity at ^(34)Si,such as the 2_(2)^(+)state of the spherical ground band at 4.519 MeV and the 3^(-),4^(-),and 5^(-)states of the one-particle one-hole cross-shell states at approximately 4.5 MeV.This nucleus,for a long time,has attracted much attention because of,on one side,a proton bubble structure in the ground state and,on the other side,a deformation in the second 0^(+)state,0_(2)^(+).By a comparison of the constructed level scheme with the shell model calculations,we describe the emerging structures in the ground and second 0+states and the negative-parity 3^(-)states within the framework of the shell model context.We propose a deformed rotational band with the cascading 6_(2)^(+)−4_(1)^(+)−2_(1)^(+)transitions built on the 0_(2)^(+)state.
文摘The LBGK(lattice Bhatnagar-Gross-Krook)model of the lattice Boltzmann method including second-order boundary condition treatment for curve geometry was employed to investigate the flow around particle clusters.The drag coefficient is a benchmark problem in the analysis of particle-fluid complex systems,especially,in a gas-solid fluidized bed.In the present work,the drag coefficient on a spherical particle in a cluster,was evaluated by using the momentum-exchange method directly.Two different configurations of cluster were measured based on the lattice Boltzmann method.Computational results indicated that the drag coefficient on an individual particle in a cluster depended heavily on the configuration of cluster.And the drag coefficient on the particle in the cluster was lower when that particle was shielded by other particles.Additionally,except for the configuration factor,both the inter-distance and Reynolds number had a strong effect on the drag coefficient on an individual particle as well.It was found that the drag coefficient on each particle varied drastically with clustering.Omitting the effect of clustering might result in incorrect drag forces in the simulation.
基金supported by the Special Funds for Major State Basic Research,PRC under the Grant G-1999-0222-08the Projects of National Natural Science Foundation of China under the Grants 50606026 and 50736006completed during a visit by one of the coauthors(LXZ) to VTT Technical Research Center of Finland,financially supported by this center
文摘The two-fluid model is widely adopted in simulations of dense gas-particle flows in engineering facili- ties. Present two-phase turbulence models for two-fluid modeling are isotropic. However, turbulence in actual gas-particle flows is not isotropic. Moreover, in these models the two-phase velocity correlation is closed using dimensional analysis, leading to discrepancies between the numerical results, theoretical analysis and experiments. To rectify this problem, some two-phase turbulence models were proposed by the authors and are applied to simulate dense gas-particle flows in downers, risers, and horizontal channels; Experimental results validate the simulation results. Among these models the USM-O and the two-scale USM models are shown to give a better account of both anisotropic particle turbulence and particle-particle collision using the transport equation model for the two-phase velocity correlation.
