No abstract

A carbene-catalyzed reaction to synthesize a chiral quinazolinone with a new activation mode of an “aniline-like” N–H moiety is disclosed. Addition of the nitrogen atom of diphenyl o-aminobenzaldehydes via NHC activation to imines leads to chiral quinazolinones with high yields and optical purities. The acidity of the N–H moiety was extremely increased through the formation of an acyl azolium intermediate, which was investigated by DFT calculations. Moreover, the chiral quinazolinones were found to have high fluorescence quantum efficiency.

Mechanical deformation of buried pipeline under vertical load is the result of pipe-soil interaction. In order to reveal the necessity of pipe-soil interaction while investigating mechanical properties of buried pipeline, the ANSYS commercial software is employed to construct pipe-soil interface and simulate pipe-soil coupling effect. With the newly developed model, mechanical properties of pipe under vertical static load are analyzed. Numerical solution is subsequently compared with analytical solution. The results reveal that (1) There is maximum Von Mises stress at internal surface of pipe side under overlying load, and minimum Von Mises stress appears in the pipe shoulder at angle of about 45°to x-axis; (2) The pipe-soil interaction has significant effect on analyzing the deformation and distribution of stress of buried pipeline; (3) Vertical displacement obtained from Marston model is larger than that obtained from newly constructed numerical model; (4) The deformation of pipe is obviously constrained by backfilled earth around the pipe. For a buried pipe, especially the elastic pipe, it is necessary to consider pipe-soil interaction while analyzing its mechanical properties.