The Antarctic Ice Sheet harbors more than 90%of the Earth ice mass,with significant losses experienced through dynamic thinning,particularly in West Antarctica.The crucial aspect of investigating ice mass balance in h...The Antarctic Ice Sheet harbors more than 90%of the Earth ice mass,with significant losses experienced through dynamic thinning,particularly in West Antarctica.The crucial aspect of investigating ice mass balance in historical periods preceding 1990 hinges on the utilization of ice velocities derived from optical satellite images.We employed declassified satellite images and Landsat images with normalized cross correlation based image matching,adopting an adaptive combination of skills and methods to overcome challenges encountered during the mapping of historical ice velocity in West Antarctica.A basin-wide synthesis velocity map encompassing the coastal regions of most large-scale glaciers and ice shelves in West Antarctica has already been successfully generated.Our results for historical ice velocities cover over 70%of the grounding line in most of the West Antarctic basins.Through adjustments,we uncovered overestimations in ice velocity measurements over an extended period,transforming our ice velocity map into a spatially deterministic,temporally average version.Among all velocity measurements,Thwaites Glacier exhibited a notable spatial variation in the fastest ice flowline and velocity distribution.Overestimation distributions on Thwaites Glacier displayed a clear consistency with the positions of subsequent front calving events,offering insights into the instabilities of ice shelves.展开更多
目的观察黄芪桂枝五物汤加减联合针刺治疗重症骨创伤患者重症监护病房(intensive care unit,ICU)获得性衰弱的效果。方法将66例重症骨创伤ICU获得性衰弱患者,按照随机数字表法分为对照组33例和观察组33例。对照组给予功能锻炼,观察组在...目的观察黄芪桂枝五物汤加减联合针刺治疗重症骨创伤患者重症监护病房(intensive care unit,ICU)获得性衰弱的效果。方法将66例重症骨创伤ICU获得性衰弱患者,按照随机数字表法分为对照组33例和观察组33例。对照组给予功能锻炼,观察组在此基础上联合黄芪桂枝五物汤加减联合针刺,连续治疗2周。比较两组的临床疗效、机械通气时间、ICU住院天数、日常生活活动能力Barthel指数(BI)评分、APACHEⅡ评分、肌力状态(MRC)评分。结果观察组的有效率90.91%(30/33),高于对照组的有效率69.70%(23/33)(P<0.05);观察组机械通气天数、住ICU时间明显短于对照组(P<0.05);治疗14d,观察组患者的BI等级优于对照组(P<0.05);治疗3d、治疗5d、治疗7d的观察组的APACHEⅡ评分明显低于对照组,肌力状态MRC评分明显高于对照组(P<0.05)。结论黄芪桂枝五物汤加减联合针刺治疗能明显缩短重症骨创伤ICU获得性衰弱患者的机械通气时间、ICU住院天数,提高日常活动能力,改善肢体肌力,更利于促进疾病康复。展开更多
针对动车组车载变压器油纸绝缘剩余寿命预测中单性能退化指标难以全面反映油纸绝缘退化过程的问题,考虑车载变压器油纸绝缘退化的个体差异性及两性能指标间的相关关系,提出了基于Copula函数的两性能指标相关退化的油纸绝缘剩余寿命预测...针对动车组车载变压器油纸绝缘剩余寿命预测中单性能退化指标难以全面反映油纸绝缘退化过程的问题,考虑车载变压器油纸绝缘退化的个体差异性及两性能指标间的相关关系,提出了基于Copula函数的两性能指标相关退化的油纸绝缘剩余寿命预测方法:采用具有随机效应的维纳过程建立油纸绝缘的两性能指标相关退化模型,基于赤池信息准则(Akaike Information Criterion, AIC)选择拟合效果更优的Copula函数来描述两性能指标间的相关关系,采用最大似然估计法估计初始时刻的模型参数,基于序列贝叶斯更新方法在线更新退化模型中的漂移系数,以实现油纸绝缘剩余寿命的在线预测。最后以加速热老化试验下油纸绝缘的聚合度和抗拉强度的退化数据进行实例验证。结果表明,两性能指标相关退化模型比单性能指标退化模型的剩余寿命预测值与实际值之间的平均绝对误差更小,预测的准确性更高,且随着模型参数不断更新,剩余寿命的预测值与实际值间的绝对误差在不断减小,预测结果的准确性在不断提升。展开更多
基金supported by the National Key Research and Development Program of China (Grant no.2021YFB3900105)the support from the Fundamental Research Funds for the Central Universitiesthe support by the National Key Research and Development Program of China (Grant no.2017YFA0603100).
文摘The Antarctic Ice Sheet harbors more than 90%of the Earth ice mass,with significant losses experienced through dynamic thinning,particularly in West Antarctica.The crucial aspect of investigating ice mass balance in historical periods preceding 1990 hinges on the utilization of ice velocities derived from optical satellite images.We employed declassified satellite images and Landsat images with normalized cross correlation based image matching,adopting an adaptive combination of skills and methods to overcome challenges encountered during the mapping of historical ice velocity in West Antarctica.A basin-wide synthesis velocity map encompassing the coastal regions of most large-scale glaciers and ice shelves in West Antarctica has already been successfully generated.Our results for historical ice velocities cover over 70%of the grounding line in most of the West Antarctic basins.Through adjustments,we uncovered overestimations in ice velocity measurements over an extended period,transforming our ice velocity map into a spatially deterministic,temporally average version.Among all velocity measurements,Thwaites Glacier exhibited a notable spatial variation in the fastest ice flowline and velocity distribution.Overestimation distributions on Thwaites Glacier displayed a clear consistency with the positions of subsequent front calving events,offering insights into the instabilities of ice shelves.
文摘目的观察黄芪桂枝五物汤加减联合针刺治疗重症骨创伤患者重症监护病房(intensive care unit,ICU)获得性衰弱的效果。方法将66例重症骨创伤ICU获得性衰弱患者,按照随机数字表法分为对照组33例和观察组33例。对照组给予功能锻炼,观察组在此基础上联合黄芪桂枝五物汤加减联合针刺,连续治疗2周。比较两组的临床疗效、机械通气时间、ICU住院天数、日常生活活动能力Barthel指数(BI)评分、APACHEⅡ评分、肌力状态(MRC)评分。结果观察组的有效率90.91%(30/33),高于对照组的有效率69.70%(23/33)(P<0.05);观察组机械通气天数、住ICU时间明显短于对照组(P<0.05);治疗14d,观察组患者的BI等级优于对照组(P<0.05);治疗3d、治疗5d、治疗7d的观察组的APACHEⅡ评分明显低于对照组,肌力状态MRC评分明显高于对照组(P<0.05)。结论黄芪桂枝五物汤加减联合针刺治疗能明显缩短重症骨创伤ICU获得性衰弱患者的机械通气时间、ICU住院天数,提高日常活动能力,改善肢体肌力,更利于促进疾病康复。
文摘针对动车组车载变压器油纸绝缘剩余寿命预测中单性能退化指标难以全面反映油纸绝缘退化过程的问题,考虑车载变压器油纸绝缘退化的个体差异性及两性能指标间的相关关系,提出了基于Copula函数的两性能指标相关退化的油纸绝缘剩余寿命预测方法:采用具有随机效应的维纳过程建立油纸绝缘的两性能指标相关退化模型,基于赤池信息准则(Akaike Information Criterion, AIC)选择拟合效果更优的Copula函数来描述两性能指标间的相关关系,采用最大似然估计法估计初始时刻的模型参数,基于序列贝叶斯更新方法在线更新退化模型中的漂移系数,以实现油纸绝缘剩余寿命的在线预测。最后以加速热老化试验下油纸绝缘的聚合度和抗拉强度的退化数据进行实例验证。结果表明,两性能指标相关退化模型比单性能指标退化模型的剩余寿命预测值与实际值之间的平均绝对误差更小,预测的准确性更高,且随着模型参数不断更新,剩余寿命的预测值与实际值间的绝对误差在不断减小,预测结果的准确性在不断提升。
