Showing papers by "National University of Defense Technology published in 1990"
TL;DR: A static-exchange formalism is proposed based on the assumption that the scattering electron undergoes the same interaction as the extra electron in the negative ion of the target atom, and a quasirelativistic approach is applied to the calculations of the negative-ion structures and the scattering processes.
Abstract: A static-exchange formalism is proposed based on the assumption that the scattering electron undergoes the same interaction as the extra electron in the negative ion of the target atom. In this method the wave function of the negative ion of the target atom is calculated, and the wave function of the frozen neutral core of the negative ion is used in the calculation of the interaction of scattering electron with the target atom. The screening effect of the incident electron on the target atom is approximated by that of the absorbed extra electron on the neutral core of the corresponding negative ion. The spin-polarization effect of the incident electron on the closed-shell target atoms is also considered by spin-polarized self-consistent field calculations for the negative-ion structures. A parameter-free spin-polarized correlation-polarization potential is included to represent the correlation and polarization effects in both the structure and scattering calculations. In order to account for the relativistic effects for heavy targets, a quasirelativistic approach is applied to the calculations of the negative-ion structures and the scattering processes. The results of low-energy electron scattering with Ca, Sr, Ba, and Ra atoms are given for energies between 0.01 and 5 eV.
18 citations
21 May 1990
TL;DR: The authors define a projection index which is suitable for practical use and derive a way to obtain the optimum projecting matrix, i.e. one that maximizes the projection index.
Abstract: The authors discuss a method called projection pursuit, which can compress dimensions of feature space. They define a projection index which is suitable for practical use and derive a way to obtain the optimum projecting matrix, i.e. one that maximizes the projection index. The results obtained can be used to project multifeature patterns can be projected to one-dimensional or two-dimensional space, and they will be more easily recognized. >
2 citations
TL;DR: In this paper, a two-direction spatial smoothing preprocessing method is presented, based on the Evans method, and it is proved that the decorrelation, the effective aperture and the maximum number of distinguishable coherent signals (when array size is given) of the new method are better than those of the Evans' method.
Abstract: Based on Evans’ spatial smoothing preprocessing scheme, a new approach called two-direction spatial smoothing preprocessing method is presented. It is proved that the decorrelation, the effective aperture and the maximum number of distinguishable coherent signals (when array size is given) of the new method are better than those of the Evans’ method. Simulation results give a comparison between the eigenvector spectrums produced by the two methods.