目的改善精密/超精密成形磨削中砂轮存在磨粒分布不均匀的问题。方法仿真分析针-环电极空间电场强度的分布特性,以及喷嘴轴线上场强随喷嘴直径、环状电极直径、电极间距的变化规律。金刚石磨粒均匀分散在静电喷雾溶液中,在高压电场和压...目的改善精密/超精密成形磨削中砂轮存在磨粒分布不均匀的问题。方法仿真分析针-环电极空间电场强度的分布特性,以及喷嘴轴线上场强随喷嘴直径、环状电极直径、电极间距的变化规律。金刚石磨粒均匀分散在静电喷雾溶液中,在高压电场和压力泵的作用下将喷出形成微表面。通过网格分析法和截距法定量分析金刚石颗粒微表面分布的均匀性。结果针-环电极产生的空间电场是对称分布的,电场线集中分布在喷嘴附近,其电场强度沿轴线向外急剧降低。由于尖端效应,喷嘴直径减小,其尖端处的电场强度明显增大;电极间距增大,喷嘴处的场强降低。网格计数法中,网格划分得越细,微表面颗粒分布偏差越大,即分布均匀性越差,但更能反映真实的颗粒整体分布情况,且各偏差曲线分布的趋势基本相同,仅在液体流量20 m L/h处出现了与理论的变化规律不符合的情况。截距法中,当液体流量增大时,颗粒间距离偏差值逐渐降低,且在液体流量20 m L/h处明显下降。结论在金刚石颗粒微表面分布的定量化分析中,网格计数法只能体现区域分布的均匀性,而对某块区域内颗粒的距离不敏感,无法区分颗粒聚集的情况,导致计算结果出现偏差。截距法则对颗粒的间距比较敏感,因此有效地结合网格计算法和截距法可以对金刚石磨粒的分布情况做出准确分析。展开更多
目的探讨家属参与的临终关怀小组干预模式对肺癌晚期患者生活质量的影响。方法 2013年至2016年在我院治疗的84例肺癌晚期患者,按家属及患者意愿,48例纳入观察组(家属参与的临终关怀),36例纳入对照组(常规护理),比较两组患者生活质量、...目的探讨家属参与的临终关怀小组干预模式对肺癌晚期患者生活质量的影响。方法 2013年至2016年在我院治疗的84例肺癌晚期患者,按家属及患者意愿,48例纳入观察组(家属参与的临终关怀),36例纳入对照组(常规护理),比较两组患者生活质量、心理状态、疼痛程度、护理满意度上差异。结果观察组与对照组在生活质量得分(64.2±6.5 vs 59.1±6.7)、疼痛程度(U=4.431,P=0.041)、汉密尔顿焦虑量表(33.1±4.3 vs 34.5±4.1)、汉密尔顿抑郁量表(46.3±5.2 vs 47.6±5.7)及护理满意度(48.1±1.2 vs33.8±0.9)差异均具有统计学意义。结论对肺癌晚期患者实行家属参与的临终关怀小组干预模式,有利于提高患者生存质量、缓解疼痛、改善心理问题及提高护理满意度。展开更多
Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the...Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the sense of safety by staff and equipments.Magnetic flux leakage detection method(MFL),as an effective method,is these days widely used in detection of broken strands of wire ropes.In order to improve the accuracy of detection of flaws in wire ropes by magnetic flux leakage(MFL),the effect of the distance between a sensor and the surface of a wire rope(i.e.,lift-off) on detection by magnetic flux leakage was in-vestigated.An analysis of the main principles for the choice of lift-off is described by us and a new method that improves the structure of the detector is proposed from the point of view of the design of a magnetic circuit,to restrain the impact of fluctuations of sensor lift-off.The effect of this kind of method is validated by simulation and computation.The results show that the detection sensitivity is markedly increased by this method.Furthermore,the signal-to-noise ratio(SNR) can be increased by over 28%.This method will lend itself to offer reliable scientific information to optimize the structure of excitation devices and improve the accuracy of MFL detection.展开更多
文摘目的改善精密/超精密成形磨削中砂轮存在磨粒分布不均匀的问题。方法仿真分析针-环电极空间电场强度的分布特性,以及喷嘴轴线上场强随喷嘴直径、环状电极直径、电极间距的变化规律。金刚石磨粒均匀分散在静电喷雾溶液中,在高压电场和压力泵的作用下将喷出形成微表面。通过网格分析法和截距法定量分析金刚石颗粒微表面分布的均匀性。结果针-环电极产生的空间电场是对称分布的,电场线集中分布在喷嘴附近,其电场强度沿轴线向外急剧降低。由于尖端效应,喷嘴直径减小,其尖端处的电场强度明显增大;电极间距增大,喷嘴处的场强降低。网格计数法中,网格划分得越细,微表面颗粒分布偏差越大,即分布均匀性越差,但更能反映真实的颗粒整体分布情况,且各偏差曲线分布的趋势基本相同,仅在液体流量20 m L/h处出现了与理论的变化规律不符合的情况。截距法中,当液体流量增大时,颗粒间距离偏差值逐渐降低,且在液体流量20 m L/h处明显下降。结论在金刚石颗粒微表面分布的定量化分析中,网格计数法只能体现区域分布的均匀性,而对某块区域内颗粒的距离不敏感,无法区分颗粒聚集的情况,导致计算结果出现偏差。截距法则对颗粒的间距比较敏感,因此有效地结合网格计算法和截距法可以对金刚石磨粒的分布情况做出准确分析。
文摘目的探讨家属参与的临终关怀小组干预模式对肺癌晚期患者生活质量的影响。方法 2013年至2016年在我院治疗的84例肺癌晚期患者,按家属及患者意愿,48例纳入观察组(家属参与的临终关怀),36例纳入对照组(常规护理),比较两组患者生活质量、心理状态、疼痛程度、护理满意度上差异。结果观察组与对照组在生活质量得分(64.2±6.5 vs 59.1±6.7)、疼痛程度(U=4.431,P=0.041)、汉密尔顿焦虑量表(33.1±4.3 vs 34.5±4.1)、汉密尔顿抑郁量表(46.3±5.2 vs 47.6±5.7)及护理满意度(48.1±1.2 vs33.8±0.9)差异均具有统计学意义。结论对肺癌晚期患者实行家属参与的临终关怀小组干预模式,有利于提高患者生存质量、缓解疼痛、改善心理问题及提高护理满意度。
文摘Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the sense of safety by staff and equipments.Magnetic flux leakage detection method(MFL),as an effective method,is these days widely used in detection of broken strands of wire ropes.In order to improve the accuracy of detection of flaws in wire ropes by magnetic flux leakage(MFL),the effect of the distance between a sensor and the surface of a wire rope(i.e.,lift-off) on detection by magnetic flux leakage was in-vestigated.An analysis of the main principles for the choice of lift-off is described by us and a new method that improves the structure of the detector is proposed from the point of view of the design of a magnetic circuit,to restrain the impact of fluctuations of sensor lift-off.The effect of this kind of method is validated by simulation and computation.The results show that the detection sensitivity is markedly increased by this method.Furthermore,the signal-to-noise ratio(SNR) can be increased by over 28%.This method will lend itself to offer reliable scientific information to optimize the structure of excitation devices and improve the accuracy of MFL detection.
