A finite element model is constructed for a sliding friction bearing in a seismically isolated bridge under vertical excitation with contact/friction elements. The effects of vertical excitation on the seismic perform...A finite element model is constructed for a sliding friction bearing in a seismically isolated bridge under vertical excitation with contact/friction elements. The effects of vertical excitation on the seismic performance of a seismically isolated bridge with sliding friction bearings and different bearing friction coefficients and different stiffness levels （pier diameter） are discussed using example calculations, and the effects of excitation direction for vertical excitation on the analysis results are explored. The analysis results shows that vertical excitation has a relatively large impact on seismic performance for a seismically isolated bridge with sliding friction bearings, which should be considered when designing a seismically isolated bridge with sliding friction bearings where vertical excitation dominates.展开更多
The analytical layer-elements for a single poroelastic soil layer and the underlying half-space are established using an algebraic manipulation and Hankel trans- form. According to the boundary conditions and adjacent...The analytical layer-elements for a single poroelastic soil layer and the underlying half-space are established using an algebraic manipulation and Hankel trans- form. According to the boundary conditions and adjacent continuity conditions of general stresses and displacements, a global matrix equation in the transform domain for multi- layered saturated soil media is assembled and solved. Solutions in the frequency domain can be further obtained with an inverse Hankel transform. Numerical examples are used to examine accuracy of the present method and demonstrate effects of soil parameters and load conditions on dynamic responses of the multilayered poroelastic saturated soils.展开更多
Density functional theory B3LYP method with 6-31＋＋G＊＊ basis was used to optimize the geometries of the ground states for 1,2,3-triazine-（H2O）n（n=1,2,3） complexes. All calculations indicate that the 1,2,3- tria...Density functional theory B3LYP method with 6-31＋＋G＊＊ basis was used to optimize the geometries of the ground states for 1,2,3-triazine-（H2O）n（n=1,2,3） complexes. All calculations indicate that the 1,2,3- triazine-water complexes in the ground states have strong hydrogen-bonding interaction, and the complex having a N… .H-O hydrogen bond and a chain of water molecules which is terminated by a O. … .H-C hydrogen bond is the most stable. The H-O stretching modes of complexes are red-shifted relative to that of the monomer. In addition, the Natural bond orbit （NBO） analysis indicates that the intermolecular charge transfer between 1,2,3-triazine and water is 0.0222e, 0.0261e and 0.0273e for the most stable 1：1, 1：2 and 1：3 complexes, respectively. The first singlet （n, π＊） vertical excitation energy of the monomer 1,2,3-triazine and the hydrogen-bonding complexes of 1,2,3-triazine-（H2O）n were investigated by time-dependent density functional theory.展开更多
The electron and heavy hole energy levels of two vertically coupled In As hemispherical quantum dots/wetting layers embedded in a Ga As barrier are calculated numerically. As the radius increases, the electronic energ...The electron and heavy hole energy levels of two vertically coupled In As hemispherical quantum dots/wetting layers embedded in a Ga As barrier are calculated numerically. As the radius increases, the electronic energies increase for the small base radii and decrease for the larger ones. The energies decrease as the dot height increases. The intersubband and interband transitions of the system are also studied. For both, a spectral peak position shift to lower energies is seen due to the vertical coupling of dots. The interband transition energy decreases as the dot size increases, decreases for the dot shapes with larger heights, and reaches a minimum for coupled semisphere dots.展开更多
基金National Natural Science Foundation of China under Grant Nos.51368036 and 51108220
文摘A finite element model is constructed for a sliding friction bearing in a seismically isolated bridge under vertical excitation with contact/friction elements. The effects of vertical excitation on the seismic performance of a seismically isolated bridge with sliding friction bearings and different bearing friction coefficients and different stiffness levels （pier diameter） are discussed using example calculations, and the effects of excitation direction for vertical excitation on the analysis results are explored. The analysis results shows that vertical excitation has a relatively large impact on seismic performance for a seismically isolated bridge with sliding friction bearings, which should be considered when designing a seismically isolated bridge with sliding friction bearings where vertical excitation dominates.
文摘The analytical layer-elements for a single poroelastic soil layer and the underlying half-space are established using an algebraic manipulation and Hankel trans- form. According to the boundary conditions and adjacent continuity conditions of general stresses and displacements, a global matrix equation in the transform domain for multi- layered saturated soil media is assembled and solved. Solutions in the frequency domain can be further obtained with an inverse Hankel transform. Numerical examples are used to examine accuracy of the present method and demonstrate effects of soil parameters and load conditions on dynamic responses of the multilayered poroelastic saturated soils.
文摘Density functional theory B3LYP method with 6-31＋＋G＊＊ basis was used to optimize the geometries of the ground states for 1,2,3-triazine-（H2O）n（n=1,2,3） complexes. All calculations indicate that the 1,2,3- triazine-water complexes in the ground states have strong hydrogen-bonding interaction, and the complex having a N… .H-O hydrogen bond and a chain of water molecules which is terminated by a O. … .H-C hydrogen bond is the most stable. The H-O stretching modes of complexes are red-shifted relative to that of the monomer. In addition, the Natural bond orbit （NBO） analysis indicates that the intermolecular charge transfer between 1,2,3-triazine and water is 0.0222e, 0.0261e and 0.0273e for the most stable 1：1, 1：2 and 1：3 complexes, respectively. The first singlet （n, π＊） vertical excitation energy of the monomer 1,2,3-triazine and the hydrogen-bonding complexes of 1,2,3-triazine-（H2O）n were investigated by time-dependent density functional theory.
文摘The electron and heavy hole energy levels of two vertically coupled In As hemispherical quantum dots/wetting layers embedded in a Ga As barrier are calculated numerically. As the radius increases, the electronic energies increase for the small base radii and decrease for the larger ones. The energies decrease as the dot height increases. The intersubband and interband transitions of the system are also studied. For both, a spectral peak position shift to lower energies is seen due to the vertical coupling of dots. The interband transition energy decreases as the dot size increases, decreases for the dot shapes with larger heights, and reaches a minimum for coupled semisphere dots.
