目的探讨心电图T波峰末间期(Tp-Te)、Tp-Te/QT比值对恶性室性心律失常(MVA)的诊断价值。方法连续入选2017年1月1日至2018年1月1日于保定市第一中心医院西院心电图、脑电图二室行24 h 12导联动态心电图检查的患者412例为研究对象。根据...目的探讨心电图T波峰末间期(Tp-Te)、Tp-Te/QT比值对恶性室性心律失常(MVA)的诊断价值。方法连续入选2017年1月1日至2018年1月1日于保定市第一中心医院西院心电图、脑电图二室行24 h 12导联动态心电图检查的患者412例为研究对象。根据是否发生恶性室性心律失常分为两组:恶性室性心律失常组72例;无恶性室性心律失常组340例。分别测定两组患者Tp-Te间期、QT间期,计算出Tp-Te间期、QTc间期及Tp-Te/QT比值,并对两组患者Tp-Te间期、QTc间期及Tp-Te/QT比值进行统计学分析。结果恶性室性心律失常组的Tp-Te间期、Tp-Te/QT比值均较非恶性室性心律失常组明显增加(P<0.001)。结论Tp-Te间期、Tp-Te/QT比值增加对于恶性室性心律失常的发生均有预测价值。展开更多
Due to traffic and wave actions, cast steel joints are subjected to variable-amplitude fatigue loading, which may cause fatigue problems. The ratio of the minimum strain to the maximum strain(strain ratio)can be emplo...Due to traffic and wave actions, cast steel joints are subjected to variable-amplitude fatigue loading, which may cause fatigue problems. The ratio of the minimum strain to the maximum strain(strain ratio)can be employed to analyze the influence of variable-amplitude fatigue both in the elastic and plastic ranges. To evaluate the effect of the strain ratio on G20Mn5 QT cast steel, the fatigue tests of smooth specimens were carried out at the strain ratio of 0.1. The cyclic deformation and the relationships between the strain amplitude, the stress amplitude, the Smith, Watson and Topper(SWT)parameter and fatigue life were studied and compared with those at the strain ratio of-1. Compared with other methods, Basquin formula and Solonberg formula provide reliable and appropriate ranges of S-N curve and fatigue limit at different strain ratios respectively. The SWT parameter can be used to predict the fatigue life at other strain ratios accurately.展开更多
文摘目的探讨心电图T波峰末间期(Tp-Te)、Tp-Te/QT比值对恶性室性心律失常(MVA)的诊断价值。方法连续入选2017年1月1日至2018年1月1日于保定市第一中心医院西院心电图、脑电图二室行24 h 12导联动态心电图检查的患者412例为研究对象。根据是否发生恶性室性心律失常分为两组:恶性室性心律失常组72例;无恶性室性心律失常组340例。分别测定两组患者Tp-Te间期、QT间期,计算出Tp-Te间期、QTc间期及Tp-Te/QT比值,并对两组患者Tp-Te间期、QTc间期及Tp-Te/QT比值进行统计学分析。结果恶性室性心律失常组的Tp-Te间期、Tp-Te/QT比值均较非恶性室性心律失常组明显增加(P<0.001)。结论Tp-Te间期、Tp-Te/QT比值增加对于恶性室性心律失常的发生均有预测价值。
基金Supported by the National Natural Science Foundation of China(No.51178307 and No.51525803)
文摘Due to traffic and wave actions, cast steel joints are subjected to variable-amplitude fatigue loading, which may cause fatigue problems. The ratio of the minimum strain to the maximum strain(strain ratio)can be employed to analyze the influence of variable-amplitude fatigue both in the elastic and plastic ranges. To evaluate the effect of the strain ratio on G20Mn5 QT cast steel, the fatigue tests of smooth specimens were carried out at the strain ratio of 0.1. The cyclic deformation and the relationships between the strain amplitude, the stress amplitude, the Smith, Watson and Topper(SWT)parameter and fatigue life were studied and compared with those at the strain ratio of-1. Compared with other methods, Basquin formula and Solonberg formula provide reliable and appropriate ranges of S-N curve and fatigue limit at different strain ratios respectively. The SWT parameter can be used to predict the fatigue life at other strain ratios accurately.
