A novel type of chiral molecular clefts was designed and synthesized by using chenodeoxycholic acid as spacer and aromatic compounds as arm.Their structures were confirmed by 1H NMR,IR,MS spectra and elemental analysi...A novel type of chiral molecular clefts was designed and synthesized by using chenodeoxycholic acid as spacer and aromatic compounds as arm.Their structures were confirmed by 1H NMR,IR,MS spectra and elemental analysis.Enantioselective recognition properties of these molecular clefts for amino acid methyl esters were investigated by UV-vis spectra titration. The results indicated that these molecular clefts not only recognize all amino acid methyl esters examined but also possess higher selectivity for L-amino acid methyl esters than for D-amino acid methyl esters.展开更多
A series of new molecular clefts are synthesized in good yields by using lithocholic acid as spacer to bridge different aromatic amines via triphosgene under microwave irradiation.Their structures are characterized by...A series of new molecular clefts are synthesized in good yields by using lithocholic acid as spacer to bridge different aromatic amines via triphosgene under microwave irradiation.Their structures are characterized by 1H NMR,IR,MS spectra and elemental analysis.Compared with the conventional method,this method is simple,safe,rapid,efficient and eco-friendly.展开更多
The influences of subsurface cracks,distributing along the axial direction,on the rolling contact fatigue(RCF)faliure in a bearing ring are investigated.A realistic three-dimensional model of the bearing ring containi...The influences of subsurface cracks,distributing along the axial direction,on the rolling contact fatigue(RCF)faliure in a bearing ring are investigated.A realistic three-dimensional model of the bearing ring containing three subsurface cracks is used to evaluate the fatigue crack propagation based on stress intensity factor(SIF)calculations.Moreover,the distributions of the subsurface cracks along the axial direction are varied to study their effects on RCF.The results provide valuable guidelines for enhanced understanding of RCF in bearings.展开更多
文摘A novel type of chiral molecular clefts was designed and synthesized by using chenodeoxycholic acid as spacer and aromatic compounds as arm.Their structures were confirmed by 1H NMR,IR,MS spectra and elemental analysis.Enantioselective recognition properties of these molecular clefts for amino acid methyl esters were investigated by UV-vis spectra titration. The results indicated that these molecular clefts not only recognize all amino acid methyl esters examined but also possess higher selectivity for L-amino acid methyl esters than for D-amino acid methyl esters.
文摘A series of new molecular clefts are synthesized in good yields by using lithocholic acid as spacer to bridge different aromatic amines via triphosgene under microwave irradiation.Their structures are characterized by 1H NMR,IR,MS spectra and elemental analysis.Compared with the conventional method,this method is simple,safe,rapid,efficient and eco-friendly.
基金supported by the National Basic Research Program of China(Grant No.2011CB706605)State Key Program of National Natural Science Foundation of China(Grant No.51135007)+1 种基金Innovative Research Groups of the National Natural Science Foundation of Hubei Province(Grant No.2011CDA12)the Fundamental Research Funds for the Central Universities(Grant Nos.2012-Ia-017,2013-IV-014)for the support given to this research
文摘The influences of subsurface cracks,distributing along the axial direction,on the rolling contact fatigue(RCF)faliure in a bearing ring are investigated.A realistic three-dimensional model of the bearing ring containing three subsurface cracks is used to evaluate the fatigue crack propagation based on stress intensity factor(SIF)calculations.Moreover,the distributions of the subsurface cracks along the axial direction are varied to study their effects on RCF.The results provide valuable guidelines for enhanced understanding of RCF in bearings.
