The polystyrene sulfonic acid resin catalysts were fabricated, containing elements of Cl and Mg through oxidization and impregnation, and they were characterized by EDS, FT-IR spectra, Py-IR spectra, UV spectra, XPS and TGA to investigate their physiochemical properties. The catalytic performances of these catalysts were examined in the esterification reaction of succinic acid with n-butanol, and the catalytic results showed that modified resins exhibited the highest catalytic activity and achieved a high yield of dibutyl succinate (91.6%) in addition, the modified resin generated new Lewis acid sites and showed significantly higher thermal stability. The experimental results demonstrated that the Mg2+ coordinated with a sulfonic acid group to form stable active sites, which effectively decreased the deactivation caused by the thermal degradation of sulfonic acid. Moreover, the monomer structures of polystyrene sulfonic acid resin and modified polystyrene sulfonic acid resin have been modelled using B3LYP/6-311G(d,p) approximation.

ABSTRACT: Terminal area is an important part of airspace system. Its operation efficiency is related to the safety, order and efficiency of the entire air traffic. So the assessment of the terminal route network operation efficiency is needed. Considering the aspects of route segment capacity, flight flow, workload and operation stability, the paper analyzes the influent factors on the operation efficiency of terminal area route network, constructs the calculation parameters of operating efficiency, and establishes the calculation model of operating efficiency of the route segment. An assessment model for the operation efficiency of terminal area route network based on flight demand is built using comprehensive weighted method. Finally, the feasibility of the assessment model is verified by analyzing a case. The model can be used to assess not only the operation efficiency of a single route segment based on different flight demands in the terminal area, but also the real-time efficiency of the terminal area route network.

SSRs have proved to be the most powerful tool for variety identification in groundnut of similar origin, and have much potential in genetic and breeding studies. To facilitate SSR discovery in groundnut, we proposed a highly simplified SSR isolation protocol based on multiple enzyme digestion/ligation, mixed biotin-labeled probes and streptavidin coated magnetic beads hybridization capture strategy. Of the 272 colonies randomly picked for sequencing, 119 were found to have unique SSR inserts