评估超声引导下经皮经肝穿刺胆道镜取石术(PTCS)在治疗肝移植术后胆道并发症中的有效性和安全性。方法 本研究回顾性分析了2022年1月至2023年6月期间,在湘雅二医院接受PTCS治疗的肝移植术后胆道并发症患者43例。患者根据治疗方式不同分...评估超声引导下经皮经肝穿刺胆道镜取石术(PTCS)在治疗肝移植术后胆道并发症中的有效性和安全性。方法 本研究回顾性分析了2022年1月至2023年6月期间,在湘雅二医院接受PTCS治疗的肝移植术后胆道并发症患者43例。患者根据治疗方式不同分为两组:对比组21例,接受其他内镜胆道治疗:ERCP及经口胆道镜(POCS);实验组22例,接受PTCS治疗。两组在基线数据上进行匹配。评估指标包括治疗成功率、并发症发生率、患者生存率及生活质量和再次干预的需求。结果 实验组在胆石的清除率(79.77%vs.74.21%)和胆管狭窄的改善情况(74.03% vs. 59.79%)上均优于对比组,两组间差异具有统计学意义(P<0.05)。实验组的并发症发生率(出血4.55%,感染9.09%,胆管损伤4.55%)低于对比组(出血4.76%,感染9.52%,胆管损伤14.29%),且具有统计学意义(P<0.05)。实验组的整体生存率为100%,显著高于对比组的95.24%(P<0.05),且生活质量评分也更高(70.31 vs. 65.83,P<0.05)。实验组再次干预的需求显著低于对比组(9.09% vs. 23.81%,P<0.05)。结论 超声引导下的PTCS在治疗肝移植术后胆道并发症中显示出较高的治疗成功率和较低的并发症风险,同时能显著提高患者的生存率和生活质量,减少再次干预的需求。因此,PTCS可作为一种有效和安全的治疗选项。展开更多
该文基于信息系统物理化的设想提出电力信息物理系统(cyber-physical power system,CPPS)中的信息流建模和计算分析方法。采用连续时间函数来刻画信息流的特征,并定义信息网络运行参数为流量累积函数、信息流速和时延。首先,基于遍历法...该文基于信息系统物理化的设想提出电力信息物理系统(cyber-physical power system,CPPS)中的信息流建模和计算分析方法。采用连续时间函数来刻画信息流的特征,并定义信息网络运行参数为流量累积函数、信息流速和时延。首先,基于遍历法搜索出信息流路径,建立信息流速矩阵的范式;然后利用改进的网络演算(network calculus,NC)特性赋值流速矩阵的元素;进一步采用流量累积函数表征信源数据发送规律,从而显式求解时延上界。最后将提出的信息流建模方法应用于智能变电站自动化系统的时延计算,通过与OPNET的仿真结果相比较,验证所提出模型的有效性,而且该方法可以提供定量分析指标以优化变电站组网方案设计中的信息流分布。展开更多
以整体优化抬落道量最小为目标进行纵断面重构时,由于纵断面整体优化中各线元数学模型不同,拟合后的线元连接处会存在错位现象,不满足相邻线元首尾相接的平顺性条件。因此,本文提出了利用引入相切条件的方向加速(Powell with Tangent Co...以整体优化抬落道量最小为目标进行纵断面重构时,由于纵断面整体优化中各线元数学模型不同,拟合后的线元连接处会存在错位现象,不满足相邻线元首尾相接的平顺性条件。因此,本文提出了利用引入相切条件的方向加速(Powell with Tangent Condition,PTC)法来重构纵断面线形。首先利用方向加速(Powell)法进行各线元拟合优化,然后对竖曲线圆心坐标进行调整,通过调整后的圆心坐标重新计算纵断面竖曲线半径及直圆点和圆直点坐标,使竖曲线与左右两侧相邻直线坡段相切。对比利用PTC法与传统的曲率分段结合最小二乘法重构线形的抬落道量,结果表明,PTC法对线路重构的扰动更小,优化效果更好,在减小抬落道方面有显著优势。通过动力学仿真对比Powell法和PTC法优化线形后的车体动力学指标,结果表明,PTC法重构纵断面所得的线元连接处平顺性显著提高,各车体动力学性能指标明显减小,车辆运行的安全性和舒适性得到明显改善。展开更多
This paper investigates the prescribed-time control(PTC) problem for a class of strict-feedback systems subject to non-vanishing uncertainties. The coexistence of mismatched uncertainties and non-vanishing disturbance...This paper investigates the prescribed-time control(PTC) problem for a class of strict-feedback systems subject to non-vanishing uncertainties. The coexistence of mismatched uncertainties and non-vanishing disturbances makes PTC synthesis nontrivial. In this work, a control method that does not involve infinite time-varying gain is proposed, leading to a practical and global prescribed time tracking control solution for the strict-feedback systems, in spite of both the mismatched and nonvanishing uncertainties. Different from methods based on control switching to avoid the issue of infinite control gain that involves control discontinuity at the switching point, in our method a softening unit is exclusively included to ensure the continuity of the control action. Furthermore, in contrast to most existing prescribed-time control works where the control scheme is only valid on a finite time interval, in this work, the proposed control scheme is valid on the entire time interval. In addition, the prior information on the upper or lower bound of gi is not in need,enlarging the applicability of the proposed method. Both the theoretical analysis and numerical simulation confirm the effectiveness of the proposed control algorithm.展开更多
An easy workup and environmentally friendly method to convert ethylbenzene into the corresponding oxides, catalyzed by a combined catalytic system consisting of NHPI and CoSPc, was developed in a water involved liquid...An easy workup and environmentally friendly method to convert ethylbenzene into the corresponding oxides, catalyzed by a combined catalytic system consisting of NHPI and CoSPc, was developed in a water involved liquid-liquid heterogeneous system. Experimental results showed that the reaction performed well facilitated by PTCs at multigrams material level, under which the conversion rate of ethylbenzene and the selectivity of acetophenone reached 60.6% and 95.2% after 0.5 h of reaction in oxygen atmosphere. An oxidation process was orooosed at the end of this oaoer.展开更多
文摘评估超声引导下经皮经肝穿刺胆道镜取石术(PTCS)在治疗肝移植术后胆道并发症中的有效性和安全性。方法 本研究回顾性分析了2022年1月至2023年6月期间,在湘雅二医院接受PTCS治疗的肝移植术后胆道并发症患者43例。患者根据治疗方式不同分为两组:对比组21例,接受其他内镜胆道治疗:ERCP及经口胆道镜(POCS);实验组22例,接受PTCS治疗。两组在基线数据上进行匹配。评估指标包括治疗成功率、并发症发生率、患者生存率及生活质量和再次干预的需求。结果 实验组在胆石的清除率(79.77%vs.74.21%)和胆管狭窄的改善情况(74.03% vs. 59.79%)上均优于对比组,两组间差异具有统计学意义(P<0.05)。实验组的并发症发生率(出血4.55%,感染9.09%,胆管损伤4.55%)低于对比组(出血4.76%,感染9.52%,胆管损伤14.29%),且具有统计学意义(P<0.05)。实验组的整体生存率为100%,显著高于对比组的95.24%(P<0.05),且生活质量评分也更高(70.31 vs. 65.83,P<0.05)。实验组再次干预的需求显著低于对比组(9.09% vs. 23.81%,P<0.05)。结论 超声引导下的PTCS在治疗肝移植术后胆道并发症中显示出较高的治疗成功率和较低的并发症风险,同时能显著提高患者的生存率和生活质量,减少再次干预的需求。因此,PTCS可作为一种有效和安全的治疗选项。
文摘该文基于信息系统物理化的设想提出电力信息物理系统(cyber-physical power system,CPPS)中的信息流建模和计算分析方法。采用连续时间函数来刻画信息流的特征,并定义信息网络运行参数为流量累积函数、信息流速和时延。首先,基于遍历法搜索出信息流路径,建立信息流速矩阵的范式;然后利用改进的网络演算(network calculus,NC)特性赋值流速矩阵的元素;进一步采用流量累积函数表征信源数据发送规律,从而显式求解时延上界。最后将提出的信息流建模方法应用于智能变电站自动化系统的时延计算,通过与OPNET的仿真结果相比较,验证所提出模型的有效性,而且该方法可以提供定量分析指标以优化变电站组网方案设计中的信息流分布。
文摘以整体优化抬落道量最小为目标进行纵断面重构时,由于纵断面整体优化中各线元数学模型不同,拟合后的线元连接处会存在错位现象,不满足相邻线元首尾相接的平顺性条件。因此,本文提出了利用引入相切条件的方向加速(Powell with Tangent Condition,PTC)法来重构纵断面线形。首先利用方向加速(Powell)法进行各线元拟合优化,然后对竖曲线圆心坐标进行调整,通过调整后的圆心坐标重新计算纵断面竖曲线半径及直圆点和圆直点坐标,使竖曲线与左右两侧相邻直线坡段相切。对比利用PTC法与传统的曲率分段结合最小二乘法重构线形的抬落道量,结果表明,PTC法对线路重构的扰动更小,优化效果更好,在减小抬落道方面有显著优势。通过动力学仿真对比Powell法和PTC法优化线形后的车体动力学指标,结果表明,PTC法重构纵断面所得的线元连接处平顺性显著提高,各车体动力学性能指标明显减小,车辆运行的安全性和舒适性得到明显改善。
基金supported by the National Natural Science Foundation of China (61991400, 61991403, 62273064, 62250710167,61860206008, 61933012, 62203078)in part by the National Key Research and Development Program of China (2022YFB4701400/4701401)+1 种基金the Innovation Support Program for International Students Returning to China(cx2022016)the CAAI-Huawei MindSpore Open Fund。
文摘This paper investigates the prescribed-time control(PTC) problem for a class of strict-feedback systems subject to non-vanishing uncertainties. The coexistence of mismatched uncertainties and non-vanishing disturbances makes PTC synthesis nontrivial. In this work, a control method that does not involve infinite time-varying gain is proposed, leading to a practical and global prescribed time tracking control solution for the strict-feedback systems, in spite of both the mismatched and nonvanishing uncertainties. Different from methods based on control switching to avoid the issue of infinite control gain that involves control discontinuity at the switching point, in our method a softening unit is exclusively included to ensure the continuity of the control action. Furthermore, in contrast to most existing prescribed-time control works where the control scheme is only valid on a finite time interval, in this work, the proposed control scheme is valid on the entire time interval. In addition, the prior information on the upper or lower bound of gi is not in need,enlarging the applicability of the proposed method. Both the theoretical analysis and numerical simulation confirm the effectiveness of the proposed control algorithm.
基金Fundamental Research Funds for the Central Universities (No. 10CX04024A)the financial support from Natural Science Foundation of Shandong Province (No. 2009ZRA05107)
文摘An easy workup and environmentally friendly method to convert ethylbenzene into the corresponding oxides, catalyzed by a combined catalytic system consisting of NHPI and CoSPc, was developed in a water involved liquid-liquid heterogeneous system. Experimental results showed that the reaction performed well facilitated by PTCs at multigrams material level, under which the conversion rate of ethylbenzene and the selectivity of acetophenone reached 60.6% and 95.2% after 0.5 h of reaction in oxygen atmosphere. An oxidation process was orooosed at the end of this oaoer.
