Based on density-functional theory (DFT) and wave function analysis procedures, the optical and molecular absorption properties of two structurally different pentacyclooxonium salt molecules have been investigated, and the physical mechanism of the formation of a built-in electric field due to orbital polarization caused by structural distortions, which induces charge transfer and leads to a nonlinear optical spectrum, has been explored.The properties result from the orbital polarization-induced built-in electric field driving charge transfer due to structural distortion. Theoretical analysis of ultraviolet-visible absorption spectroscopy (UV-vis) spectra is first performed to investigate the optical properties. The electronic excitation characteristics of the built-in electric field-driven charge transfer in molecules are analyzed in detail by transition density matrix (TDM) and charge differential density (CDD). Combining transition electric dipole moment density (TEDM) and transition magnetic dipole moment density (TMDM) analysis, the physical mechanism of the structure-induced chirality in their electronic circular dichroism (ECD) spectra is revealed. The results can provide theoretical references for the preparation of novel chiral materials as well as the research and development of optoelectronic materials and their practical applications.

In order to study the influences of swing, H₂O and N₂ on the removal of CO₂ from offshore natural gas by adsorption and purification, dynamic penetration experiments of mixed multi?component gas in the dry and aqueous 13X zeolites under static and swing conditions were carried out. Mixtures of CH₄/ CO₂ and CH₄/ CO₂/ N₂ were obtained by matching CH₄, CO₂, and N₂ in proportion through a mass spectrometer. In addition, under static and swing conditions, the partial pressure of each gas in the mixtures at the exit of the dry and aqueous 13X zeolites at different time was measured during dynamic penetration experiments, and the penetration curve and penetration time were obtained. The adsorption and purification effect of CO₂ in the two mixtures in the dry and aqueous 13X zeolites under the two conditions was analyzed according to the penetration time, and then the influences of swing, H₂O and N₂ on the removal of CO₂ from offshore natural gas by adsorption and purification were clarified. The experimental results show that 13X zeolites have the strongest capacity in absorbing CO₂ and the weakest capacity in absorbing N₂ under static or swing conditions. N₂ is conducive to the removal of CO₂ from offshore natural gas by adsorption and purification, while the swing and H₂O fail to do so.

A series of S, P, Si?doped TiO₂ supports and the corresponding VO_x/TiO₂ catalysts were prepared by sol?gel method and impregnation method for the purpose of enhancing SCR performance.Among them,the S?doped VO_x/TiO₂ catalyst exhibited the best low and medium temperature SCR performance and the widest active temperature window.According to the results of various analyses,the doping greatly influenced the agglomeration of vanadium species.As a result, numerous active polymeric VO_x species were emerged on the surface of catalysts.Meanwhile,S and Si was doped into TiO₂ lattice via the replacement of Ti⁴⁺ by S⁴⁺ and Si⁴⁺ to generate Ti-O-S and Ti-O-Si bonds,along with producing more surface V⁴⁺+V³⁺ and more chemisorbed oxygen species.The synergistic effect of the two active species can promote the oxidation of NO to NO₂,which can participate in the fast?SCR reaction by accelerating the reoxidation of VO_x species in the Redox process,and then improve the SCR performance of VO_x/TiO₂ catalyst at low and medium temperature range.The redox ability and activity of P?doped VO_x/TiO₂ catalyst are relatively low,because more phosphate is produced in the catalyst.Although doping S,P and Si has a significant effect on the acidity of the catalyst,it is not the dominate factor to determine the SCR activity.