Fourteen conformers of 3-amino-1-propanol as the minima on the potential energy surface are examined at the MP2/6-311＋＋G＊＊ level. Their relative energies calculated at B3LYP, MP3 and MP4 levels of theory indicated...Fourteen conformers of 3-amino-1-propanol as the minima on the potential energy surface are examined at the MP2/6-311＋＋G＊＊ level. Their relative energies calculated at B3LYP, MP3 and MP4 levels of theory indicated that two most stable conformers display the intramolecular OH - N hydrogen bonds. The vertical ionization energies of these conformers calculated with ab initio electron propagator theory in the P3/aug-cc-pVTZ approximation are in agreement with experimental data from photoelectron spectroscopy. Natural bond orbital analyses were used to explain the differences of IEs of the highest occupied molecular ortibal of conformers. Combined with statistical mechanics principles, conformational distributions at various temperatures are obtained and the temperature dependence of photoelectron spectra is interpreted.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
This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways.An analytical expression of the mapping relationship between the pier settlement and the rail deformation...This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways.An analytical expression of the mapping relationship between the pier settlement and the rail deformation is derived theoretically for the double block ballastless track-bridge system.By adopting the superposition of the track random irregularity and the rail deformation caused by the pier settlement as the excitation inputs,the variations of vehicle dynamics indices with pier settlement are comparatively analyzed.Then,the safety threshold of the bridge pier settlement is obtained according to the limit of vehicle running safety and ride comfort indices of the high-speed trains.Results show that the dynamics indices of different trains have different sensitivities to the pier settlement,and the train CRH2C is the most sensitive one among all the types of Chinese high-speed trains.When passing through the bridges in common span with pier settlement at the speed of 250–350 km/h,the trains suffer the low-frequency excitations,and the vertical acceleration of car body is most sensitive to the pier settlement of all the dynamics indices.When the car body vertical acceleration just exceeds the allowable limit,the critical settlement value is 23.4 mm,which is much bigger than the pier differential settlement limit in the current code for Chinese high-speed railways.展开更多
The orbital magnetization of the electron gas on a two-dimensional kagome' lattice under a perpendicular magnetic field is theoretically investigated.The interplay between the lattice geometry and magnetic field i...The orbital magnetization of the electron gas on a two-dimensional kagome' lattice under a perpendicular magnetic field is theoretically investigated.The interplay between the lattice geometry and magnetic field induces nontrivial k-space Chern invariant in the magnetic Brillouin zone,which turns to result in profound effects on the magnetization properties.We show that the Berry-phase term in the magnetization gives a paramagnetic contribution,while the conventional term brought about by the magnetic response of the magnetic Bloch bands produces a diamagnetic contribution.As a result,the superposition of these two components gives rise to a delicate oscillatory structure in the magnetization curve when varying the electron filling factor.The relationship between this oscillatory behavior and the Hofstadter energy spectrum is revealed by selectively discussing the magnetization and its two components at the commensurate fluxes of f = 1/4,1/3,and 1/6,respectively.In particular,we reveal as a typical example the fractal structure in the magnetic oscillations by tuning the commensurate flux around f = 1/4.The finite-temperature effect on the magnetization is also discussed.展开更多
基金This work was supported by the Province Natural Science Foundation of Henan （No.082300410030）, the Foundation of Henan Educational Committee （No.2011A140015）, and the Doctoral Research Pund of Henan Normal University （No.525449）.
文摘Fourteen conformers of 3-amino-1-propanol as the minima on the potential energy surface are examined at the MP2/6-311＋＋G＊＊ level. Their relative energies calculated at B3LYP, MP3 and MP4 levels of theory indicated that two most stable conformers display the intramolecular OH - N hydrogen bonds. The vertical ionization energies of these conformers calculated with ab initio electron propagator theory in the P3/aug-cc-pVTZ approximation are in agreement with experimental data from photoelectron spectroscopy. Natural bond orbital analyses were used to explain the differences of IEs of the highest occupied molecular ortibal of conformers. Combined with statistical mechanics principles, conformational distributions at various temperatures are obtained and the temperature dependence of photoelectron spectra is interpreted.
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.
基金supported by the National Basic Research Program of China("973"Program)(Grant Nos.2013CB036206 and 2013CB036205)the National Natural Science Foundation of China(Grant No.50838006)+1 种基金the Research Project of State Key Laboratory of Traction Power(Grant No.2014TPL_T01)the 2015 Doctors’Innovation Fund of Southwest Jiaotong University
文摘This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways.An analytical expression of the mapping relationship between the pier settlement and the rail deformation is derived theoretically for the double block ballastless track-bridge system.By adopting the superposition of the track random irregularity and the rail deformation caused by the pier settlement as the excitation inputs,the variations of vehicle dynamics indices with pier settlement are comparatively analyzed.Then,the safety threshold of the bridge pier settlement is obtained according to the limit of vehicle running safety and ride comfort indices of the high-speed trains.Results show that the dynamics indices of different trains have different sensitivities to the pier settlement,and the train CRH2C is the most sensitive one among all the types of Chinese high-speed trains.When passing through the bridges in common span with pier settlement at the speed of 250–350 km/h,the trains suffer the low-frequency excitations,and the vertical acceleration of car body is most sensitive to the pier settlement of all the dynamics indices.When the car body vertical acceleration just exceeds the allowable limit,the critical settlement value is 23.4 mm,which is much bigger than the pier differential settlement limit in the current code for Chinese high-speed railways.
基金supported by the National Natural Science Foundation of China(Grant Nos.90921003,10904005,60776061 and 60776063)the National Basic Research Program of China(Grant Nos.2009CB929103 and 2009CB929300)
文摘The orbital magnetization of the electron gas on a two-dimensional kagome' lattice under a perpendicular magnetic field is theoretically investigated.The interplay between the lattice geometry and magnetic field induces nontrivial k-space Chern invariant in the magnetic Brillouin zone,which turns to result in profound effects on the magnetization properties.We show that the Berry-phase term in the magnetization gives a paramagnetic contribution,while the conventional term brought about by the magnetic response of the magnetic Bloch bands produces a diamagnetic contribution.As a result,the superposition of these two components gives rise to a delicate oscillatory structure in the magnetization curve when varying the electron filling factor.The relationship between this oscillatory behavior and the Hofstadter energy spectrum is revealed by selectively discussing the magnetization and its two components at the commensurate fluxes of f = 1/4,1/3,and 1/6,respectively.In particular,we reveal as a typical example the fractal structure in the magnetic oscillations by tuning the commensurate flux around f = 1/4.The finite-temperature effect on the magnetization is also discussed.
