The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic fu...The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic functions in the unit ball by radial derivative.Then we extend the Sharma's results.展开更多
The avalanche multiplication principle of electron multiplication CCD (EMCCD) was discussed on the basis of single type of carrier, and the multiplication model was built by using a classic piecewise ionization rate m...The avalanche multiplication principle of electron multiplication CCD (EMCCD) was discussed on the basis of single type of carrier, and the multiplication model was built by using a classic piecewise ionization rate model and avalanche multiplication integral formula. Wolff's ionization rate model was selected according to the structure and the multiplication gate amplitude of the actual devices. Compared the theoretical result with the multiplication curve of the actual device, it was found that only enough fringing field strength and multiplication area length could lead to adequate signal charge multiplication. The relationship between the multiplication gate amplitude and the total gain of the cascaded boosting EMCCD can be conveniently determined by using this model.展开更多
Objective:Multiple myeloma(MM)is a hematologically malignant clonal plasma cell disease.This study aims to explore the association between immunophenotypes and prognosis in patients with MM,to determine whether the ex...Objective:Multiple myeloma(MM)is a hematologically malignant clonal plasma cell disease.This study aims to explore the association between immunophenotypes and prognosis in patients with MM,to determine whether the expression of CD45 and CD200 is related to the prognosis of newly diagnosed MM(NDMM)patients,and to evaluate the significance of the combined expression of CD45 and CD200 in NDMM.Methods:A total of 123 NDMM patients admitted to Shengjing Hospital of China Medical University from July 2015 to August 2019 were enrolled.Five key immunophenotypic markers(including CD38,CD138,CD45,CD56,and CD200)were screened through flow cytometry and identified using random forest analysis and univariate Cox regression analysis.Patients were divided into 3 groups:Group A,CD45 and CD200 double-positive;Group B,CD45 or CD200 single-positive;Group C,CD45 and CD200 double-negative.Kaplan-Meier curves were used to analyze overall survival(OS)and progression-free survival(PFS)across groups.Multivariate Cox regression was performed to evaluate prognostic factors,and a nomogram was constructed based on these results.Results:The OS and PFS of single-positive groups for CD38,CD138,CD45,CD56,and CD200 were all shorter than those of their respective single-negative groups(all P<0.05).Significant differences were observed in OS(P<0.001)and PFS(P=0.001)among Groups A,B,and C.Group A had shorter OS and PFS(all P=0.001)compared to the Group B+C(cases from Group B and Group C were combined).CD45 and CD200 double-positive was an independent prognostic factor for NDMM[hazard ratio(HR)=2.178,95%confidence interval(CI)1.048 to 4.529;P=0.037].The nomogram and calibration curves constructed from multivariate Cox regression analysis demonstrated good concordance(concordance index=0.706;95%CI 0.661 to 0.751).Conclusion:NDMM patients with double-positive expression of CD45 and CD200 have significantly shorter OS and PFS.Compared with the use of either marker alone,the combined assessment of CD45 and CD200 may provide better prognostic stratification for MM patients.展开更多
The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs b...The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs based on M-EMLs separated by polyethyleneimine ethoxylated(PEIE)layer with different stacking sequences of blue(B),green(G),and red(R)QDs layer were used to intuitively explore the injection,transportation and recombination processes of the charge carriers in QLEDs by using the time-resolved electroluminescence(TrEL)spectra.From the TrEL spectra mea-surements,green and red emissions were obtained first in the QLEDs with the EMLs sequences of G/PEIE/B/PEIE/R and B/PEIE/R/PEIE/G along the direction of light emission,respectively.While the QLEDs adopt EMLs sequences of B/PEIE/G/PEIE/R,the blue,green and red emissions were obtained nearly at the same time.The above phenomenon can be attributed to different charge carrier transmission and radiation recombination process in the EMLs due to different valence band offsets and conduction band offsets between R-,G-and B-QDs by using different sequences of EMLs.White emission with coordi-nates of(0.31,0.31)and correlated color temperature(CCT)of 5916 K was obtained in the QLEDs with the EMLs se-quences of B/PEIE/G/PEIE/R,which can be attributed to the relative uniform emission of B-,G-and R-QDs due to the effec-tive injection and radiation recombination of charge carriers in each of the EMLs.The above results have great significance for further understanding and improving the performance of QLEDs with M-EMLs.展开更多
Multiple quadrotors target encirclement is widely used in the intelligent field,as it can effectively monitor and control target behavior.However,it faces the danger of collision,as well as difficulties in localizatio...Multiple quadrotors target encirclement is widely used in the intelligent field,as it can effectively monitor and control target behavior.However,it faces the danger of collision,as well as difficulties in localization and tracking.Therefore,we propose a complete target encirclement method.Firstly,based on Hooke's law,a collision avoidance controller is designed to maintain a safe flying distance among quadrotors.Then,based on the consensus theory,a formation tracking controller is designed to meet the requirements of formation transformation and encirclement tasks,and a stability proof based on Lyapunov was provided.Besides,the target detection is designed based on YOLOv5s,and the target location model is constructed based on the principle of pinhole projection and triangle similarity.Finally,we conducted experiments on the built platform,with 3 reconnaissance quadrotors detecting and localization 3 target vehicles and 7 hunter quadrotors tracking them.The results show that the minimum average error for localization targets with reconnaissance quadrotors can reach 0.1354 m,while the minimum average error for tracking with hunter quadrotors is only 0.2960 m.No quadrotors collision occurred in the whole formation transformation and tracking experiment.In addition,compared with the advanced methods,the proposed method has better performance.展开更多
Red mud is a solid waste discharged in the process of alumina production,and how to realize the efficient recovery of its iron is an urgent problem to be solved.In this study,the iron extraction test and mechanism stu...Red mud is a solid waste discharged in the process of alumina production,and how to realize the efficient recovery of its iron is an urgent problem to be solved.In this study,the iron extraction test and mechanism study of high iron red mud were carried out under the coupling conditions of multiple physical field(microwave field,gas-solid flow field and temperature field)with biomass as the reducing agent.The test results showed that under the optimal conditions,an iron concentrate with a yield of 78.4%,an iron grade of 59.23%,and a recovery rate of 86.65%was obtained.The analyses of XRD,XPS,TEM,and SEM-EDS showed that during the roasting process,the hematite in the high-iron red mud was completely converted to magnetite,and the biomass produced the reductant that provided the magnetization reaction;A large number of cracks and pores appeared in the surface of the hematite reduction product particles,which helped to induce iron minerals to undergo effective mineral phase transformation.The above study provides ideas for the phase transformation and efficient recovery of iron minerals in red mud.展开更多
As the performance of the box-type multiple launch rocket system(BMLRS)improves,its mechanical structures,particularly the plane clearance design between the slider on the rocket and the guide inside the launch canist...As the performance of the box-type multiple launch rocket system(BMLRS)improves,its mechanical structures,particularly the plane clearance design between the slider on the rocket and the guide inside the launch canister,have grown increasingly complex.However,deficiencies still exist in the current launch modeling theory for BMLRS.In this study,a multi-rigid-flexible-body launch dynamics model coupling the launch platform and rocket was established using the multibody system transfer matrix method and the Newton-Euler formulation.Furthermore,considering the bending of the launch canister,a detection algorithm for slider-guide plane clearance contact was proposed.To quantify the contact force and friction effect between the slider and guide,the contact force model and modified Coulomb model were introduced.Both the modal and launch tests were conducted.Additionally,the modal convergence was verified.By comparing the modal experiments and simulation results,the maximum relative error of the eigenfrequency is 3.29%.thereby verifying the accuracy of the developed BMLRS dynamics model.Furthermore,the launch test validated the proposed plane clearance contact model.Moreover,the study investigated the influence of various model parameters on the dynamic characteristics of BMLRS,including launch canister bending stiffness,slider and guide material,slider-guide clearance,slider length and layout.This analysis of influencing factors provides a foundation for future optimization in BMLRS design.展开更多
The existence of T_periodic solutions of the nonlinear system with multiple delays is studied. By using the topological degree method, sufficient conditions are obtained for the existence of T_periodic solutions. As a...The existence of T_periodic solutions of the nonlinear system with multiple delays is studied. By using the topological degree method, sufficient conditions are obtained for the existence of T_periodic solutions. As an application, the existence of positive periodic solution for a logarithmic population model is established under some conditions.展开更多
背景良好用药依从性可显著降低脑卒中患者复发风险,是脑卒中患者二级预防的关键。然而,现有研究多针对农村脑卒中患者的短期用药及依从行为,而对同类患者的长期用药依从行为的研究较为有限。目的本研究旨在分析中国农村地区脑卒中幸存...背景良好用药依从性可显著降低脑卒中患者复发风险,是脑卒中患者二级预防的关键。然而,现有研究多针对农村脑卒中患者的短期用药及依从行为,而对同类患者的长期用药依从行为的研究较为有限。目的本研究旨在分析中国农村地区脑卒中幸存者的长期用药行为、依从态度与行为,并识别与用药行为相关的因素。方法基于2017年在河北省南和县5个乡镇、60个村开展的农村地区脑卒中患者管理研究——中国农村地区脑卒中管理的系统整合技术辅助照护模式研究(SINEMA),本研究对象为曾参与过2017年SINEMA研究且同意参与2024年5—7月随访并完成调查的所有脑卒中幸存者。调查研究对象降压药、他汀类药、抗血小板药和降糖药的用药情况,并使用Maastricht Utrecht Adherence in Hypertension-16(MUAH-16)量表评估其用药依从态度(积极的医疗与药物态度维度)。采用Morisky Green Levine量表测量服用4类药物的患者的用药依从行为(得分为0分定义为依从性高)。使用描述性分析展示患者基本特征、用药依从性状况和多因素Logistic回归分析识别出的相关因素。结果本研究共纳入912名研究对象,平均年龄为(72.0±7.9)岁,其中女性占46.1%(420/912);在药物服用方面,有772例(84.6%)患者自报服用降压药,547例(59.9%)服用抗血小板药,427例(46.8%)服用他汀类药,以及203例(22.3%)服用降糖药。在正在服用4类药物的人群中,降糖药服用依从性为77.3%(157/203),降压药服用依从性为71.5%(552/772)、抗血小板药物服用依从性为71.2%(392/547),他汀类药服用依从性为71.2%(304/427)。调查结果显示49.2%(449/912)的患者具有积极的医疗与药物态度。多因素Logistic回归分析结果显示,在服用降压药的患者中,受教育程度较高(中学及以上:OR=1.87,95%CI=1.13~3.09)、具有积极的医疗与药物态度(OR=1.53,95%CI=1.08~2.17)的患者用药依从性高,可独立完成工作(OR=0.56,95%CI=0.32~0.99)、去村卫生所≥1次/月者(OR=0.68,95%CI=0.53~0.88)用药依从性较低(P<0.05)。在服用抗血小板药的患者中,受教育程度较高(中学及以上:OR=1.79,95%CI=1.09~2.96)的患者用药依从性较高,出血性脑卒中患者(OR=0.55,95%CI=0.31~0.98)用药依从性较低(P<0.05)。在服用他汀类药的患者中,去村卫生所≥1次/月者(OR=0.67,95%CI=0.46~0.98)用药依从性较低(P<0.05)。在服用降糖药的患者中,男性(OR=0.21,95%CI=0.06~0.73)、注册慢性疾病重大疾病保险(OR=0.34,95%CI=0.15~0.79)、去村卫生所≥1次/月者(OR=0.34,95%CI=0.13~0.89)用药依从性较低(P<0.05)。结论本研究结果显示,农村地区具有较长疾病史的脑卒中幸存者具有相对较高的用药依从性,但仍有近三成患者未能规律依从诊疗建议,不同药物类型依从行为的影响因素存在差异,应开展个性化的用药依从干预,增加患者的用药依从性及二级预防行为。展开更多
Group decision making problems are investigated with uncertain multiplicative linguistic preference relations.An unbalanced multiplicative linguistic label set is introduced,which can be used by the experts to express...Group decision making problems are investigated with uncertain multiplicative linguistic preference relations.An unbalanced multiplicative linguistic label set is introduced,which can be used by the experts to express their linguistic preference information over alternatives.The uncertain linguistic weighted geometric mean operator is utilized to aggregate all the individual uncertain multiplicative linguistic preference relations into a collective one,and then a simple approach is developed to determine the experts＇ weights by utilizing the consensus degrees among the individual uncertain multiplicative linguistic preference relations and the collective uncertain multiplicative linguistic preference relations.Furthermore,a practical interactive procedure for group decision making is proposed based on uncertain multiplicative linguistic preference relations,in which a possibility degree formula and a complementary matrix are used to rank the given alternatives.Finally,the proposed procedure is applied to solve the group decision making problem of a manufacturing company searching the best global supplier for one of its most critical parts used in assembling process.展开更多
Influence of multiple structural parameters on the performance of a gun launch system driven by highpressure reactive gases is important for structural design and performance adjustment.A coupled lumped parameter mode...Influence of multiple structural parameters on the performance of a gun launch system driven by highpressure reactive gases is important for structural design and performance adjustment.A coupled lumped parameter model was utilized to predict the propellant combustion,and a dynamic finite element method was applied to approximate the mechanical interactions between the projectile and the barrel.The combustion and the mechanical interactions were coupled through a user subroutine interface in ABAQUS.The correctness and the capability of the finite element approximations in capturing small structural changes were validated by comparing predicted resistance with experiments.Based on the coupled model,the influence of structural parameters of a medium-caliber gun on the system performance was investigated.In order to reduce the research costs,orthogonal tests were designed to investigate the comprehensive effects of the parameters.According to statistical analysis,the important order of the structural parameters on the launching process was obtained.The results indicate that the influence of the width of the rotating band stands out among the studied parameters in the gun.The work provides a method to investigate the influence of multiple parameters on system performance and gives guidance for controlling the system performance.展开更多
To improve the performance of multiple classifier system, a knowledge discovery based dynamic weighted voting （KD-DWV） is proposed based on knowledge discovery. In the method, all base classifiers may be allowed to ...To improve the performance of multiple classifier system, a knowledge discovery based dynamic weighted voting （KD-DWV） is proposed based on knowledge discovery. In the method, all base classifiers may be allowed to operate in different measurement/feature spaces to make the most of diverse classification information. The weights assigned to each output of a base classifier are estimated by the separability of training sample sets in relevant feature space. For this purpose, some decision tables （DTs） are established in terms of the diverse feature sets. And then the uncertainty measures of the separability are induced, in the form of mass functions in Dempster-Shafer theory （DST）, from each DTs based on generalized rough set model. From the mass functions, all the weights are calculated by a modified heuristic fusion function and assigned dynamically to each classifier varying with its output. The comparison experiment is performed on the hyperspectral remote sensing images. And the experimental results show that the performance of the classification can be improved by using the proposed method compared with the plurality voting （PV）.展开更多
In an ambiguous decision domain, the evaluation values of alternatives against attributes would be interval numbers because of the inherent, uncertain property of the problems. By using a number of linear programming ...In an ambiguous decision domain, the evaluation values of alternatives against attributes would be interval numbers because of the inherent, uncertain property of the problems. By using a number of linear programming models, Bryson and Mobolurin propose an approach to compute attribute weights and overall values of the alternatives in the form of interval numbers. The intervals of the overall values of alternatives are then transformed into points or crisp values for comparisons among the alternatives. However, the attribute weights are different because of the use of linear programming models in Bryson and Mobolurin＇s approach. Thus, the alternatives are not comparable because different attribute weights are employed to calculate the overall values of the alternatives. A new approach is proposed to overcome the drawbacks of Bryson and Mobolurin＇s approach. By transforming the decision matrix with intervals into the one with crisp values, a new linear programming model is proposed, to calculate the attribute weights for conducting alternative ranking.展开更多
The problem of channel estimation for multiple an- tenna orthogonal frequency division multiplexing （OFDM） systems subject to unknown carrier frequency offset （CFO） is addressed. Multiple signal classification （M...The problem of channel estimation for multiple an- tenna orthogonal frequency division multiplexing （OFDM） systems subject to unknown carrier frequency offset （CFO） is addressed. Multiple signal classification （MUSIC）-Iike algorithm, which generally has been used for direction estimation or frequency estimation, is used for channel estimation in multiple antenna OFDM systems. A reduced dimensional （RD）-MUSIC based algorithm for channel estimation is proposed in multiple antenna OFDM systems with unknown CFO. The Cramer-Rao bound （CRB） of channel estimation in multiple antenna OFDM systems with unknown CFO is derived. The proposed algorithm has a superior performance of channel estimation compared with the Capon method and the least squares method.展开更多
基金Supported by Natural Science Foundation of Guangdong Province in China(2018KTSCX161)。
文摘The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic functions in the unit ball by radial derivative.Then we extend the Sharma's results.
文摘The avalanche multiplication principle of electron multiplication CCD (EMCCD) was discussed on the basis of single type of carrier, and the multiplication model was built by using a classic piecewise ionization rate model and avalanche multiplication integral formula. Wolff's ionization rate model was selected according to the structure and the multiplication gate amplitude of the actual devices. Compared the theoretical result with the multiplication curve of the actual device, it was found that only enough fringing field strength and multiplication area length could lead to adequate signal charge multiplication. The relationship between the multiplication gate amplitude and the total gain of the cascaded boosting EMCCD can be conveniently determined by using this model.
基金supported by the National Natural Science Foundation,China(81870166).
文摘Objective:Multiple myeloma(MM)is a hematologically malignant clonal plasma cell disease.This study aims to explore the association between immunophenotypes and prognosis in patients with MM,to determine whether the expression of CD45 and CD200 is related to the prognosis of newly diagnosed MM(NDMM)patients,and to evaluate the significance of the combined expression of CD45 and CD200 in NDMM.Methods:A total of 123 NDMM patients admitted to Shengjing Hospital of China Medical University from July 2015 to August 2019 were enrolled.Five key immunophenotypic markers(including CD38,CD138,CD45,CD56,and CD200)were screened through flow cytometry and identified using random forest analysis and univariate Cox regression analysis.Patients were divided into 3 groups:Group A,CD45 and CD200 double-positive;Group B,CD45 or CD200 single-positive;Group C,CD45 and CD200 double-negative.Kaplan-Meier curves were used to analyze overall survival(OS)and progression-free survival(PFS)across groups.Multivariate Cox regression was performed to evaluate prognostic factors,and a nomogram was constructed based on these results.Results:The OS and PFS of single-positive groups for CD38,CD138,CD45,CD56,and CD200 were all shorter than those of their respective single-negative groups(all P<0.05).Significant differences were observed in OS(P<0.001)and PFS(P=0.001)among Groups A,B,and C.Group A had shorter OS and PFS(all P=0.001)compared to the Group B+C(cases from Group B and Group C were combined).CD45 and CD200 double-positive was an independent prognostic factor for NDMM[hazard ratio(HR)=2.178,95%confidence interval(CI)1.048 to 4.529;P=0.037].The nomogram and calibration curves constructed from multivariate Cox regression analysis demonstrated good concordance(concordance index=0.706;95%CI 0.661 to 0.751).Conclusion:NDMM patients with double-positive expression of CD45 and CD200 have significantly shorter OS and PFS.Compared with the use of either marker alone,the combined assessment of CD45 and CD200 may provide better prognostic stratification for MM patients.
文摘The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs based on M-EMLs separated by polyethyleneimine ethoxylated(PEIE)layer with different stacking sequences of blue(B),green(G),and red(R)QDs layer were used to intuitively explore the injection,transportation and recombination processes of the charge carriers in QLEDs by using the time-resolved electroluminescence(TrEL)spectra.From the TrEL spectra mea-surements,green and red emissions were obtained first in the QLEDs with the EMLs sequences of G/PEIE/B/PEIE/R and B/PEIE/R/PEIE/G along the direction of light emission,respectively.While the QLEDs adopt EMLs sequences of B/PEIE/G/PEIE/R,the blue,green and red emissions were obtained nearly at the same time.The above phenomenon can be attributed to different charge carrier transmission and radiation recombination process in the EMLs due to different valence band offsets and conduction band offsets between R-,G-and B-QDs by using different sequences of EMLs.White emission with coordi-nates of(0.31,0.31)and correlated color temperature(CCT)of 5916 K was obtained in the QLEDs with the EMLs se-quences of B/PEIE/G/PEIE/R,which can be attributed to the relative uniform emission of B-,G-and R-QDs due to the effec-tive injection and radiation recombination of charge carriers in each of the EMLs.The above results have great significance for further understanding and improving the performance of QLEDs with M-EMLs.
基金the National Natural Science Foundation of China(Grant Nos.62303348 and 62173242)the Aeronautical Science Foundation of China(Grant No.2024M071048002)the National Science Fund for Distinguished Young Scholars(Grant No.62225308)to provide fund for conducting experiments.
文摘Multiple quadrotors target encirclement is widely used in the intelligent field,as it can effectively monitor and control target behavior.However,it faces the danger of collision,as well as difficulties in localization and tracking.Therefore,we propose a complete target encirclement method.Firstly,based on Hooke's law,a collision avoidance controller is designed to maintain a safe flying distance among quadrotors.Then,based on the consensus theory,a formation tracking controller is designed to meet the requirements of formation transformation and encirclement tasks,and a stability proof based on Lyapunov was provided.Besides,the target detection is designed based on YOLOv5s,and the target location model is constructed based on the principle of pinhole projection and triangle similarity.Finally,we conducted experiments on the built platform,with 3 reconnaissance quadrotors detecting and localization 3 target vehicles and 7 hunter quadrotors tracking them.The results show that the minimum average error for localization targets with reconnaissance quadrotors can reach 0.1354 m,while the minimum average error for tracking with hunter quadrotors is only 0.2960 m.No quadrotors collision occurred in the whole formation transformation and tracking experiment.In addition,compared with the advanced methods,the proposed method has better performance.
基金Project(MMCS2023OF02)supported by the Open Foundation of State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures,ChinaProject(AA23073018)supported by the Guangxi Science and Technology,ChinaProject(2024M751861)supported by the China Postdoctoral Science Foundation。
文摘Red mud is a solid waste discharged in the process of alumina production,and how to realize the efficient recovery of its iron is an urgent problem to be solved.In this study,the iron extraction test and mechanism study of high iron red mud were carried out under the coupling conditions of multiple physical field(microwave field,gas-solid flow field and temperature field)with biomass as the reducing agent.The test results showed that under the optimal conditions,an iron concentrate with a yield of 78.4%,an iron grade of 59.23%,and a recovery rate of 86.65%was obtained.The analyses of XRD,XPS,TEM,and SEM-EDS showed that during the roasting process,the hematite in the high-iron red mud was completely converted to magnetite,and the biomass produced the reductant that provided the magnetization reaction;A large number of cracks and pores appeared in the surface of the hematite reduction product particles,which helped to induce iron minerals to undergo effective mineral phase transformation.The above study provides ideas for the phase transformation and efficient recovery of iron minerals in red mud.
基金supported by National Natural Science Foundation of China(Grant No.92266201).
文摘As the performance of the box-type multiple launch rocket system(BMLRS)improves,its mechanical structures,particularly the plane clearance design between the slider on the rocket and the guide inside the launch canister,have grown increasingly complex.However,deficiencies still exist in the current launch modeling theory for BMLRS.In this study,a multi-rigid-flexible-body launch dynamics model coupling the launch platform and rocket was established using the multibody system transfer matrix method and the Newton-Euler formulation.Furthermore,considering the bending of the launch canister,a detection algorithm for slider-guide plane clearance contact was proposed.To quantify the contact force and friction effect between the slider and guide,the contact force model and modified Coulomb model were introduced.Both the modal and launch tests were conducted.Additionally,the modal convergence was verified.By comparing the modal experiments and simulation results,the maximum relative error of the eigenfrequency is 3.29%.thereby verifying the accuracy of the developed BMLRS dynamics model.Furthermore,the launch test validated the proposed plane clearance contact model.Moreover,the study investigated the influence of various model parameters on the dynamic characteristics of BMLRS,including launch canister bending stiffness,slider and guide material,slider-guide clearance,slider length and layout.This analysis of influencing factors provides a foundation for future optimization in BMLRS design.
文摘The existence of T_periodic solutions of the nonlinear system with multiple delays is studied. By using the topological degree method, sufficient conditions are obtained for the existence of T_periodic solutions. As an application, the existence of positive periodic solution for a logarithmic population model is established under some conditions.
文摘背景良好用药依从性可显著降低脑卒中患者复发风险,是脑卒中患者二级预防的关键。然而,现有研究多针对农村脑卒中患者的短期用药及依从行为,而对同类患者的长期用药依从行为的研究较为有限。目的本研究旨在分析中国农村地区脑卒中幸存者的长期用药行为、依从态度与行为,并识别与用药行为相关的因素。方法基于2017年在河北省南和县5个乡镇、60个村开展的农村地区脑卒中患者管理研究——中国农村地区脑卒中管理的系统整合技术辅助照护模式研究(SINEMA),本研究对象为曾参与过2017年SINEMA研究且同意参与2024年5—7月随访并完成调查的所有脑卒中幸存者。调查研究对象降压药、他汀类药、抗血小板药和降糖药的用药情况,并使用Maastricht Utrecht Adherence in Hypertension-16(MUAH-16)量表评估其用药依从态度(积极的医疗与药物态度维度)。采用Morisky Green Levine量表测量服用4类药物的患者的用药依从行为(得分为0分定义为依从性高)。使用描述性分析展示患者基本特征、用药依从性状况和多因素Logistic回归分析识别出的相关因素。结果本研究共纳入912名研究对象,平均年龄为(72.0±7.9)岁,其中女性占46.1%(420/912);在药物服用方面,有772例(84.6%)患者自报服用降压药,547例(59.9%)服用抗血小板药,427例(46.8%)服用他汀类药,以及203例(22.3%)服用降糖药。在正在服用4类药物的人群中,降糖药服用依从性为77.3%(157/203),降压药服用依从性为71.5%(552/772)、抗血小板药物服用依从性为71.2%(392/547),他汀类药服用依从性为71.2%(304/427)。调查结果显示49.2%(449/912)的患者具有积极的医疗与药物态度。多因素Logistic回归分析结果显示,在服用降压药的患者中,受教育程度较高(中学及以上:OR=1.87,95%CI=1.13~3.09)、具有积极的医疗与药物态度(OR=1.53,95%CI=1.08~2.17)的患者用药依从性高,可独立完成工作(OR=0.56,95%CI=0.32~0.99)、去村卫生所≥1次/月者(OR=0.68,95%CI=0.53~0.88)用药依从性较低(P<0.05)。在服用抗血小板药的患者中,受教育程度较高(中学及以上:OR=1.79,95%CI=1.09~2.96)的患者用药依从性较高,出血性脑卒中患者(OR=0.55,95%CI=0.31~0.98)用药依从性较低(P<0.05)。在服用他汀类药的患者中,去村卫生所≥1次/月者(OR=0.67,95%CI=0.46~0.98)用药依从性较低(P<0.05)。在服用降糖药的患者中,男性(OR=0.21,95%CI=0.06~0.73)、注册慢性疾病重大疾病保险(OR=0.34,95%CI=0.15~0.79)、去村卫生所≥1次/月者(OR=0.34,95%CI=0.13~0.89)用药依从性较低(P<0.05)。结论本研究结果显示,农村地区具有较长疾病史的脑卒中幸存者具有相对较高的用药依从性,但仍有近三成患者未能规律依从诊疗建议,不同药物类型依从行为的影响因素存在差异,应开展个性化的用药依从干预,增加患者的用药依从性及二级预防行为。
基金supported by the National Natural Science Foundation of China (70571087)the National Science Fund for Distinguished Young Scholars of China (70625005)
文摘Group decision making problems are investigated with uncertain multiplicative linguistic preference relations.An unbalanced multiplicative linguistic label set is introduced,which can be used by the experts to express their linguistic preference information over alternatives.The uncertain linguistic weighted geometric mean operator is utilized to aggregate all the individual uncertain multiplicative linguistic preference relations into a collective one,and then a simple approach is developed to determine the experts＇ weights by utilizing the consensus degrees among the individual uncertain multiplicative linguistic preference relations and the collective uncertain multiplicative linguistic preference relations.Furthermore,a practical interactive procedure for group decision making is proposed based on uncertain multiplicative linguistic preference relations,in which a possibility degree formula and a complementary matrix are used to rank the given alternatives.Finally,the proposed procedure is applied to solve the group decision making problem of a manufacturing company searching the best global supplier for one of its most critical parts used in assembling process.
基金the financial support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYLX_0399)
文摘Influence of multiple structural parameters on the performance of a gun launch system driven by highpressure reactive gases is important for structural design and performance adjustment.A coupled lumped parameter model was utilized to predict the propellant combustion,and a dynamic finite element method was applied to approximate the mechanical interactions between the projectile and the barrel.The combustion and the mechanical interactions were coupled through a user subroutine interface in ABAQUS.The correctness and the capability of the finite element approximations in capturing small structural changes were validated by comparing predicted resistance with experiments.Based on the coupled model,the influence of structural parameters of a medium-caliber gun on the system performance was investigated.In order to reduce the research costs,orthogonal tests were designed to investigate the comprehensive effects of the parameters.According to statistical analysis,the important order of the structural parameters on the launching process was obtained.The results indicate that the influence of the width of the rotating band stands out among the studied parameters in the gun.The work provides a method to investigate the influence of multiple parameters on system performance and gives guidance for controlling the system performance.
基金This project was supported by the National Basic Research Programof China (2001CB309403)
文摘To improve the performance of multiple classifier system, a knowledge discovery based dynamic weighted voting （KD-DWV） is proposed based on knowledge discovery. In the method, all base classifiers may be allowed to operate in different measurement/feature spaces to make the most of diverse classification information. The weights assigned to each output of a base classifier are estimated by the separability of training sample sets in relevant feature space. For this purpose, some decision tables （DTs） are established in terms of the diverse feature sets. And then the uncertainty measures of the separability are induced, in the form of mass functions in Dempster-Shafer theory （DST）, from each DTs based on generalized rough set model. From the mass functions, all the weights are calculated by a modified heuristic fusion function and assigned dynamically to each classifier varying with its output. The comparison experiment is performed on the hyperspectral remote sensing images. And the experimental results show that the performance of the classification can be improved by using the proposed method compared with the plurality voting （PV）.
基金the National Natural Science Foundation of China (70571041).
文摘In an ambiguous decision domain, the evaluation values of alternatives against attributes would be interval numbers because of the inherent, uncertain property of the problems. By using a number of linear programming models, Bryson and Mobolurin propose an approach to compute attribute weights and overall values of the alternatives in the form of interval numbers. The intervals of the overall values of alternatives are then transformed into points or crisp values for comparisons among the alternatives. However, the attribute weights are different because of the use of linear programming models in Bryson and Mobolurin＇s approach. Thus, the alternatives are not comparable because different attribute weights are employed to calculate the overall values of the alternatives. A new approach is proposed to overcome the drawbacks of Bryson and Mobolurin＇s approach. By transforming the decision matrix with intervals into the one with crisp values, a new linear programming model is proposed, to calculate the attribute weights for conducting alternative ranking.
基金supported by the National Natural Science Foundation of China(6137116961301108+1 种基金61071164)the Fundamental Research Funds for the Central Universities(NS2013024)
文摘The problem of channel estimation for multiple an- tenna orthogonal frequency division multiplexing （OFDM） systems subject to unknown carrier frequency offset （CFO） is addressed. Multiple signal classification （MUSIC）-Iike algorithm, which generally has been used for direction estimation or frequency estimation, is used for channel estimation in multiple antenna OFDM systems. A reduced dimensional （RD）-MUSIC based algorithm for channel estimation is proposed in multiple antenna OFDM systems with unknown CFO. The Cramer-Rao bound （CRB） of channel estimation in multiple antenna OFDM systems with unknown CFO is derived. The proposed algorithm has a superior performance of channel estimation compared with the Capon method and the least squares method.
