The QRS-T angle,as an index of noninvasive cardioelectric vector,is closely related to the change of heart structure and function.There are different methedologies to measure the QRS-T angle,which can be roughly divid...The QRS-T angle,as an index of noninvasive cardioelectric vector,is closely related to the change of heart structure and function.There are different methedologies to measure the QRS-T angle,which can be roughly dividedinto two types:plane angle and space angle.Studies show that the influence factors include two aspects of physiology and pathology of the angle,in pathological ways,the disease such as myocardial hypertrophy,myocardial ischemia,hypertension,ventricular arrhythmia has larger clinical significance.In recent years,the research on the risk stratification of the QRS-T angle on sudden death has made great progress,but there are still some disputes about whether the space angle can be replaced by the plane angle and the range of normal value and so on.展开更多
The investigation focusing on the mechanical behaviors at the microstructural level in composite materials can provide valuable insight into the failure mechanisms at larger scales.A micromechanics damage model which ...The investigation focusing on the mechanical behaviors at the microstructural level in composite materials can provide valuable insight into the failure mechanisms at larger scales.A micromechanics damage model which comprises the coupling of the matrix constitutive model and the cohesive zone(CZM)model at fiber-matrix interfaces is presented to evaluate the transverse tensile damage behaviors of unidirectional(UD)fiber-reinforced polymer(FRP)composites.For the polymeric matrix that exhibits highly non-linear mechanical responses,special focus is paid on the formulation of the constitutive model,which characterizes a mixture of elasticity,plasticity as well as damage.The proposed constitutive model includes the numerical implementation of a fracture plane based ellipse-parabola criterion that is an extension of the classic Mohr-Coulomb criterion,corresponding post-yield flow rule and post-failure degradation rule in the fully implicit integration scheme.The numerical results are in good agreement with experimental measurements.It is found that directly using the matrix properties measured at the ply level to characterize the mechanical responses at the constituent level may bring large discrepancies in homogenized stress-strain responses and dominant failure mechanisms.The distribution of fracture plane angles in matrix is predicted,where it is shown to provide novel insight into the microscopic damage initiation and accumulation under transverse tension.展开更多
Patients with chronic obstructive pulmonary disease(COPD)have an increased risk for cardiovascular events,and electrocardiography has an important role in detecting cardiac side effects of COPD-related hypoxia.
文摘The QRS-T angle,as an index of noninvasive cardioelectric vector,is closely related to the change of heart structure and function.There are different methedologies to measure the QRS-T angle,which can be roughly dividedinto two types:plane angle and space angle.Studies show that the influence factors include two aspects of physiology and pathology of the angle,in pathological ways,the disease such as myocardial hypertrophy,myocardial ischemia,hypertension,ventricular arrhythmia has larger clinical significance.In recent years,the research on the risk stratification of the QRS-T angle on sudden death has made great progress,but there are still some disputes about whether the space angle can be replaced by the plane angle and the range of normal value and so on.
基金support by National Science Foundation for Young Scientists of China under Grant[No.11802116].
文摘The investigation focusing on the mechanical behaviors at the microstructural level in composite materials can provide valuable insight into the failure mechanisms at larger scales.A micromechanics damage model which comprises the coupling of the matrix constitutive model and the cohesive zone(CZM)model at fiber-matrix interfaces is presented to evaluate the transverse tensile damage behaviors of unidirectional(UD)fiber-reinforced polymer(FRP)composites.For the polymeric matrix that exhibits highly non-linear mechanical responses,special focus is paid on the formulation of the constitutive model,which characterizes a mixture of elasticity,plasticity as well as damage.The proposed constitutive model includes the numerical implementation of a fracture plane based ellipse-parabola criterion that is an extension of the classic Mohr-Coulomb criterion,corresponding post-yield flow rule and post-failure degradation rule in the fully implicit integration scheme.The numerical results are in good agreement with experimental measurements.It is found that directly using the matrix properties measured at the ply level to characterize the mechanical responses at the constituent level may bring large discrepancies in homogenized stress-strain responses and dominant failure mechanisms.The distribution of fracture plane angles in matrix is predicted,where it is shown to provide novel insight into the microscopic damage initiation and accumulation under transverse tension.
文摘Patients with chronic obstructive pulmonary disease(COPD)have an increased risk for cardiovascular events,and electrocardiography has an important role in detecting cardiac side effects of COPD-related hypoxia.
