To study the influence of original defects on the dynamic stability of the columns under periodic transient loadings,the approximate solution method and the Fourier method of the stable periodic solution are adopted w...To study the influence of original defects on the dynamic stability of the columns under periodic transient loadings,the approximate solution method and the Fourier method of the stable periodic solution are adopted while considering the influence of original defects on columns.The dynamic stability of the columns under periodic transient loadings is analyzed theoretically.Through the study of different deflections,the dynamic instability of the columns is obtained by Maple software.The results of theoretical analysis show that the larger the original defects,the greater the unstable area,the stable solution amplitude of columns and the risk of instability caused by parametric resonance will be.The damping of columns is a vital factor in reducing dynamic instability at the same original defects.On the basis of the Mathieu-Hill equation,the relationship between the original defects and deflection is deduced,and the dynamic instability region of the columns under different original defects is obtained.Therefore,reducing the original defects of columns can further enhance the dynamic stability of the compressed columns in practical engineering.展开更多
Objective Reviewing the experience in diagnosis and treatment of cases with aorta-pulmonary septal defect and aortic origin of right pulmonary artery complicated with interruption of aortic arch. Methods Clinical data...Objective Reviewing the experience in diagnosis and treatment of cases with aorta-pulmonary septal defect and aortic origin of right pulmonary artery complicated with interruption of aortic arch. Methods Clinical data from medical records for 5 patients (4 boys and 1 girl,age from 1 to 18 years on admission) who had been treated in Wuhan Asia Heart Hospital between 2005 and 2009展开更多
基金The National Natural Science Foundation of Chin(No.51078354)
文摘To study the influence of original defects on the dynamic stability of the columns under periodic transient loadings,the approximate solution method and the Fourier method of the stable periodic solution are adopted while considering the influence of original defects on columns.The dynamic stability of the columns under periodic transient loadings is analyzed theoretically.Through the study of different deflections,the dynamic instability of the columns is obtained by Maple software.The results of theoretical analysis show that the larger the original defects,the greater the unstable area,the stable solution amplitude of columns and the risk of instability caused by parametric resonance will be.The damping of columns is a vital factor in reducing dynamic instability at the same original defects.On the basis of the Mathieu-Hill equation,the relationship between the original defects and deflection is deduced,and the dynamic instability region of the columns under different original defects is obtained.Therefore,reducing the original defects of columns can further enhance the dynamic stability of the compressed columns in practical engineering.
文摘Objective Reviewing the experience in diagnosis and treatment of cases with aorta-pulmonary septal defect and aortic origin of right pulmonary artery complicated with interruption of aortic arch. Methods Clinical data from medical records for 5 patients (4 boys and 1 girl,age from 1 to 18 years on admission) who had been treated in Wuhan Asia Heart Hospital between 2005 and 2009
