目的探讨连续性末梢血流灌注指数(continuous tip perfusion index,CTPI)对重症监护病房(ICU)患者压力性损伤(压伤)的预警作用,为压伤预防由主观评估改为客观测量提供依据。方法采用便利抽样法,选取2022年2月至7月入住烟台市莱阳中心医...目的探讨连续性末梢血流灌注指数(continuous tip perfusion index,CTPI)对重症监护病房(ICU)患者压力性损伤(压伤)的预警作用,为压伤预防由主观评估改为客观测量提供依据。方法采用便利抽样法,选取2022年2月至7月入住烟台市莱阳中心医院ICU中符合纳入排除标准的患者进行病例对照研究,以迈瑞监护仪N15监测患者骶尾部CTPI并记录同期Braden量表得分。采用自行设计的患者一般资料统计表收集患者的人口学特征及临床数据,包括患者床号、年龄、性别、糖尿病、心脏病、连续性肾脏代替治疗、血管活性药物使用、机械通气;采用灵敏度、特异度、受试者工作特征曲线(receiver operating characteristic curve,ROC)和曲线下面积(area under the curve,AUC)比较CTPI与Braden量表的压伤预警能力。结果患者第1~5天CTPI的AUC为0.855、0.809、0.896、0.855、0.872,最佳临界值均为0.09;Braden量表第1~5天的AUC为0.747、0.617、0.692、0.717、0.791,最佳临界值为13、13、13、12、13。结论CTPI的压伤预警能力高于现临床应用的Braden量表,其最佳临界值为0.09。展开更多
To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and...To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.展开更多
A robust H∞ directional controller for a sampled-data autonomous airship with polytopic parameter uncertainties was proposed. By input delay approach, the linearized airship model was transformed into a continuous-ti...A robust H∞ directional controller for a sampled-data autonomous airship with polytopic parameter uncertainties was proposed. By input delay approach, the linearized airship model was transformed into a continuous-time system with time-varying delay. Sufficient conditions were then established based on the constructed Lyapunov-Krasovskii functional, which guarantee that the system is mean-square exponentially stable with H∞ performance. The desired controller can be obtained by solving the obtained conditions. Simulation results show that guaranteed minimum H∞ performance γ=1.4037 and fast response of attitude for sampled-data autonomous airship are achieved in spite of the existence of parameter uncertainties.展开更多
The authors are concerned with a class of one-dimensional stochastic Anderson models with double-parameter fractional noises, whose differential operators are fractional. A unique solution for the model in some approp...The authors are concerned with a class of one-dimensional stochastic Anderson models with double-parameter fractional noises, whose differential operators are fractional. A unique solution for the model in some appropriate Hilbert space is constructed. Moreover, the Lyapunov exponent of the solution is estimated, and its HSlder continuity is studied. On the other hand, the absolute continuity of the solution is also discussed.展开更多
文摘目的探讨连续性末梢血流灌注指数(continuous tip perfusion index,CTPI)对重症监护病房(ICU)患者压力性损伤(压伤)的预警作用,为压伤预防由主观评估改为客观测量提供依据。方法采用便利抽样法,选取2022年2月至7月入住烟台市莱阳中心医院ICU中符合纳入排除标准的患者进行病例对照研究,以迈瑞监护仪N15监测患者骶尾部CTPI并记录同期Braden量表得分。采用自行设计的患者一般资料统计表收集患者的人口学特征及临床数据,包括患者床号、年龄、性别、糖尿病、心脏病、连续性肾脏代替治疗、血管活性药物使用、机械通气;采用灵敏度、特异度、受试者工作特征曲线(receiver operating characteristic curve,ROC)和曲线下面积(area under the curve,AUC)比较CTPI与Braden量表的压伤预警能力。结果患者第1~5天CTPI的AUC为0.855、0.809、0.896、0.855、0.872,最佳临界值均为0.09;Braden量表第1~5天的AUC为0.747、0.617、0.692、0.717、0.791,最佳临界值为13、13、13、12、13。结论CTPI的压伤预警能力高于现临床应用的Braden量表,其最佳临界值为0.09。
基金Project(50779032)supported by the National Natural Science Foundation of ChinaProject(20090451330)supported by the Postdoctoral Foundation of ChinaProject(BS2013SF007)supported by Shandong Scientific Research Award Foundation for Outstanding Young Scientists,China
文摘To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.
基金Projects(51205253,11272205)supported by the National Natural Science Foundation of ChinaProject(2012AA7052005)supported by the National High Technology Research and Development Program of China
文摘A robust H∞ directional controller for a sampled-data autonomous airship with polytopic parameter uncertainties was proposed. By input delay approach, the linearized airship model was transformed into a continuous-time system with time-varying delay. Sufficient conditions were then established based on the constructed Lyapunov-Krasovskii functional, which guarantee that the system is mean-square exponentially stable with H∞ performance. The desired controller can be obtained by solving the obtained conditions. Simulation results show that guaranteed minimum H∞ performance γ=1.4037 and fast response of attitude for sampled-data autonomous airship are achieved in spite of the existence of parameter uncertainties.
基金supported by the National Natural Science Foundation of China (No. 10871103)
文摘The authors are concerned with a class of one-dimensional stochastic Anderson models with double-parameter fractional noises, whose differential operators are fractional. A unique solution for the model in some appropriate Hilbert space is constructed. Moreover, the Lyapunov exponent of the solution is estimated, and its HSlder continuity is studied. On the other hand, the absolute continuity of the solution is also discussed.
