The fatigue of heavy-haul railway bridges is considered a key concern due to high stress levels and cyclic loading.The evaluation of fatigue reliability is required to include factor correlations.A major challenge is ...The fatigue of heavy-haul railway bridges is considered a key concern due to high stress levels and cyclic loading.The evaluation of fatigue reliability is required to include factor correlations.A major challenge is presented by the construction of the cumulative distribution function(CDF)and the description of correlations between random variables.In this study,the copula function is used to analyze the fatigue failure probability of the Shuohuang heavy-haul railway bridge.A C-vine copula(CVC)-based joint probability density function(JPDF)is derived with eight correlated parameters.To enhance efficiency in small failure probability calculations,the subset simulation and most probable point(MPP)Monte Carlo importance sampling are introduced based on the Rosenblatt transform and C-vine model.Comparisons with traditional Monte Carlo methods confirm that high accuracy and efficiency are achieved.The results show that when parameter correlations are ignored,failure probability is underestimated,increasing safety risks in bridge assessments.展开更多
Objective:Patients after radical gastrectomy often require medium-to long-term intravenous therapy.However,traditional central venous catheters(CVCs)have issues such as high infection risk and poor comfort.This study ...Objective:Patients after radical gastrectomy often require medium-to long-term intravenous therapy.However,traditional central venous catheters(CVCs)have issues such as high infection risk and poor comfort.This study aims to deeply explore the clinical application value of peripherally inserted central catheters(PICCs)after radical gastrectomy,providing a scientific basis for optimizing intravenous access selection.Methods:Fifty patients requiring catheterization after radical gastrectomy at the Friendship Hospital of Ili Kazak Autonomous Prefecture from December 2022 to May 2024 were selected.Catheterization site selection was based on patients’preferences,dividing them into two groups:the experimental group receiving PICCs and the control group receiving CVCs,with 25 patients in each group.Multi-dimensional comparative analysis was conducted,including catheterization operation time,catheter indwelling time,success rates of first and second catheterizations,and complication rates.Statistical methods such as t-tests and chi-square tests were used for in-depth analysis.Results:Compared to the control group,the experimental group had longer catheterization operations and catheter indwelling times,and a higher success rate of first catheterization(P<0.05).The incidence of catheterization complications in the experimental group was 12.00%,lower than the 40.00%in the control group(P<0.05).Conclusion:Although PICC catheterization after radical gastrectomy has relatively longer catheterization operation and indwelling times,it has a high success rate of first catheterization and a low complication rate,demonstrating high clinical application value and worth promoting in clinical practice.展开更多
对2300 mm CVC六辊冷轧机轧制3102合金空调箔边紧问题进行分析研究,主要因为轧辊边部散热大,热凸度不均,导致边紧肋松缺陷。通过调整输入宽度,增加板型辊测量环覆盖率,调整前后张力,增大C4和A16板形目标曲线系数,有效改善边紧肋松板形缺...对2300 mm CVC六辊冷轧机轧制3102合金空调箔边紧问题进行分析研究,主要因为轧辊边部散热大,热凸度不均,导致边紧肋松缺陷。通过调整输入宽度,增加板型辊测量环覆盖率,调整前后张力,增大C4和A16板形目标曲线系数,有效改善边紧肋松板形缺陷,并将裂变宽度由10 mm控制到5 mm以内,提高了空调箔坯料成品率。展开更多
基金Project supported by the National Natural Science Foundation of China(No.52278180)。
文摘The fatigue of heavy-haul railway bridges is considered a key concern due to high stress levels and cyclic loading.The evaluation of fatigue reliability is required to include factor correlations.A major challenge is presented by the construction of the cumulative distribution function(CDF)and the description of correlations between random variables.In this study,the copula function is used to analyze the fatigue failure probability of the Shuohuang heavy-haul railway bridge.A C-vine copula(CVC)-based joint probability density function(JPDF)is derived with eight correlated parameters.To enhance efficiency in small failure probability calculations,the subset simulation and most probable point(MPP)Monte Carlo importance sampling are introduced based on the Rosenblatt transform and C-vine model.Comparisons with traditional Monte Carlo methods confirm that high accuracy and efficiency are achieved.The results show that when parameter correlations are ignored,failure probability is underestimated,increasing safety risks in bridge assessments.
基金The Ili Kazakh Autonomous Prefecture Science and Technology Plan Project(Project No.:YJC2023A28)。
文摘Objective:Patients after radical gastrectomy often require medium-to long-term intravenous therapy.However,traditional central venous catheters(CVCs)have issues such as high infection risk and poor comfort.This study aims to deeply explore the clinical application value of peripherally inserted central catheters(PICCs)after radical gastrectomy,providing a scientific basis for optimizing intravenous access selection.Methods:Fifty patients requiring catheterization after radical gastrectomy at the Friendship Hospital of Ili Kazak Autonomous Prefecture from December 2022 to May 2024 were selected.Catheterization site selection was based on patients’preferences,dividing them into two groups:the experimental group receiving PICCs and the control group receiving CVCs,with 25 patients in each group.Multi-dimensional comparative analysis was conducted,including catheterization operation time,catheter indwelling time,success rates of first and second catheterizations,and complication rates.Statistical methods such as t-tests and chi-square tests were used for in-depth analysis.Results:Compared to the control group,the experimental group had longer catheterization operations and catheter indwelling times,and a higher success rate of first catheterization(P<0.05).The incidence of catheterization complications in the experimental group was 12.00%,lower than the 40.00%in the control group(P<0.05).Conclusion:Although PICC catheterization after radical gastrectomy has relatively longer catheterization operation and indwelling times,it has a high success rate of first catheterization and a low complication rate,demonstrating high clinical application value and worth promoting in clinical practice.
文摘对2300 mm CVC六辊冷轧机轧制3102合金空调箔边紧问题进行分析研究,主要因为轧辊边部散热大,热凸度不均,导致边紧肋松缺陷。通过调整输入宽度,增加板型辊测量环覆盖率,调整前后张力,增大C4和A16板形目标曲线系数,有效改善边紧肋松板形缺陷,并将裂变宽度由10 mm控制到5 mm以内,提高了空调箔坯料成品率。
