The band structures of a new two-dimensional triangle-shaped array geometry of 4340 steel cylinders of square cross section in an epoxy resin were studied by the plane-wave expansion and supercell calculation method. ...The band structures of a new two-dimensional triangle-shaped array geometry of 4340 steel cylinders of square cross section in an epoxy resin were studied by the plane-wave expansion and supercell calculation method. The band gaps of this type of phononic crystals with different defects were calculated such as defect-free, 60° crystal linear defect states, 120° crystal linear defect states, and 180° crystal linear defect states. It was found that the band gap will emerge in different linear defects of the phononic crystals and the bandwidth of linear defect states is larger than that of the free-defect crystal by about 2.14 times within the filling fraction F = 0.1-0.85. In addition, the influence of the filling fraction on the relative width of the minimum band gap is discussed.展开更多
PolyaIilline and its derivatives is one kind of important conductive polymer.In this paper, the active mechanism of substitution and doping on conductivity of polyanilines was studied by means of EHMO-CO method. The r...PolyaIilline and its derivatives is one kind of important conductive polymer.In this paper, the active mechanism of substitution and doping on conductivity of polyanilines was studied by means of EHMO-CO method. The result showed that doping and substitution had different active mechhosm on conductivity of polyedlines, doping lowered markedly the exciting energy of carrier, while substitution altered chieIly the band width.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10764005 and 11164034)the New Century Training Program Foundation for Talents from the Ministry of Education of China (Grant No. NCET-08-0926)
文摘The band structures of a new two-dimensional triangle-shaped array geometry of 4340 steel cylinders of square cross section in an epoxy resin were studied by the plane-wave expansion and supercell calculation method. The band gaps of this type of phononic crystals with different defects were calculated such as defect-free, 60° crystal linear defect states, 120° crystal linear defect states, and 180° crystal linear defect states. It was found that the band gap will emerge in different linear defects of the phononic crystals and the bandwidth of linear defect states is larger than that of the free-defect crystal by about 2.14 times within the filling fraction F = 0.1-0.85. In addition, the influence of the filling fraction on the relative width of the minimum band gap is discussed.
文摘PolyaIilline and its derivatives is one kind of important conductive polymer.In this paper, the active mechanism of substitution and doping on conductivity of polyanilines was studied by means of EHMO-CO method. The result showed that doping and substitution had different active mechhosm on conductivity of polyedlines, doping lowered markedly the exciting energy of carrier, while substitution altered chieIly the band width.
