To investigate the distinct properties of the helicopter rotors during circling flight,the aerodynamic and dynamic models for the main rotor are established considering the trim conditions and the flight parameters of...To investigate the distinct properties of the helicopter rotors during circling flight,the aerodynamic and dynamic models for the main rotor are established considering the trim conditions and the flight parameters of helicopters.The free wake method is introduced to compute the unsteady aerodynamic loads of the rotor characterized by distortions of rotor wakes,and the modal superposition method is used to predict the overall structural loads of the rotor.The effectiveness of the aerodynamic and the structural methods is verified by comparison with the experimental results,whereby the influences of circling direction,radius,and velocity are evaluated in both aerodynamic and dynamic aspects.The results demonstrate that the circling condition makes a great difference to the performance of rotor vortex,as well as the unsteady aerodynamic loads.With the decrease of the circling radius or the increment of the circling velocity,the thrust of the main rotor increases apparently to balance the inertial force.Meanwhile,the harmonics of aerodynamic loads in rotor disc change severely and an evident aerodynamic load shock appears at high-order components,which further causes a shift-of-peak-phase bending moment in the flap dimension.Moreover,the advancing side of blade experiences second blade/vortex interaction,whose intensity has a distinct enhancement as the circling radius decreases with the motion of vortexes.展开更多
By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we...By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we make aspecial study about centering- point curve and circling- point curve and couplercurves based on Ball’s points.展开更多
MPTP (1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine) is a byproduct formed during the synthesis of a meperidine analog. Davis (1979) and Langston (1983) reported a group of drug addicts who developed classical Parki...MPTP (1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine) is a byproduct formed during the synthesis of a meperidine analog. Davis (1979) and Langston (1983) reported a group of drug addicts who developed classical Parkinsonism after self-administration of a mixture containing MPTP, their pathological and biochemical展开更多
Prediction of water inflow into a tunnel is a crucial prerequisite for the waterproof and drainage design of mountain tunnels in water-rich areas.Based on the proposed Baiyun Mountain Tunnel project in Guangzhou,a num...Prediction of water inflow into a tunnel is a crucial prerequisite for the waterproof and drainage design of mountain tunnels in water-rich areas.Based on the proposed Baiyun Mountain Tunnel project in Guangzhou,a numerical percolation model of random fractured rock of a tunnel underpassing a water reservoir is established to study the seepage characteristics of surrounding rock,the law of water inflow,and the change of lining water pressure,considering the local artificial boundary conditions for seepage in large rock mass,.In addition,the influences of rock permeability,fracture aperture,grouting circle thickness,and penetration are analyzed.The results show that:(1)Only fractures with aperture wider than 0.1 mm can play a significant role in water conduction in rocks with the permeability lower than 10^(-11)m^(2);(2)The greater the permeability difference between the fractures and rocks,the more remarkable the effects of fractures on the surrounding rock seepage field and cavern water inflow;(3)The sensitivity of grouting waterproof function to grouting circle thickness,grouting ring penetration,and rock permeability is significantly higher than that of tunnel buried depth and fracture aperture;(4)The lining water head is much more sensitive to the grouting circle thickness and penetration than to the tunnel buried depth;(5)With the grouting range enlarging,the impact of grouting circle permeability on the precipitation pressure role of the grouting ring increases;(6)For the interesting tunnel designed to be built at the depth of 70 m,the grouting circle with the thickness of 0.5 m and permeability of 10-^(14)m^(2)is recommended.展开更多
During the final proofing stage of the paper,the wrong version of Fig.2 was accidently used when replacing it with a high-resolution version.The star and circle marks were missing in the published version.
Objective:To investigate the effectiveness of Quality Control Circle(QCC)activities in reducing the loss rate during storage of Traditional Chinese Medicine(TCM)decoction pieces in our hospital pharmacy department.Met...Objective:To investigate the effectiveness of Quality Control Circle(QCC)activities in reducing the loss rate during storage of Traditional Chinese Medicine(TCM)decoction pieces in our hospital pharmacy department.Methods:A QCC team was established to systematically analyze the causes of TCM decoction piece losses.Using quality improvement tools including Pareto charts,the 80/20 rule,and fishbone diagrams,we identified key areas for improvement and developed targeted intervention strategies.The study period spanned from January to December 2023,with pre-intervention data collected from January to December 2022.Loss rates were calculated and compared before and after QCC implementation.Results:According to the“80/20 rule”analysis,the primary improvement targets were identified as inadequate maintenance of decoction pieces and dispensing losses.Following QCC implementation,the loss rate of TCM decoction pieces decreased significantly from 1.27%(pre-intervention)to 0.65%(post-intervention),achieving an improvement rate of 47.40%.The total monetary loss decreased from 9,592.62 RMB to 4,546.97 RMB.Conclusion:QCC activities can effectively reduce the loss rate of TCM decoction pieces in hospital pharmacy departments,improve the quality of herbal medicines,ensure patient medication safety,and enhance pharmaceutical service quality.This systematic approach provides a valuable framework for continuous quality improvement in TCM pharmacy management.展开更多
The presence of circles in the network maximum flow problem increases the complexity of the preflow algorithm.This study proposes a novel two-stage preflow algorithm to address this issue.First,this study proves that ...The presence of circles in the network maximum flow problem increases the complexity of the preflow algorithm.This study proposes a novel two-stage preflow algorithm to address this issue.First,this study proves that at least one zero-flow arc must be present when the flow of the network reaches its maximum value.This result indicates that the maximum flow of the network will remain constant if a zero-flow arc within a circle is removed;therefore,the maximum flow of each network without circles can be calculated.The first stage involves identifying the zero-flow arc in the circle when the network flow reaches its maximum.The second stage aims to remove the zero-flow arc identified and modified in the first stage,thereby producing a new network without circles.The maximum flow of the original looped network can be obtained by solving the maximum flow of the newly generated acyclic network.Finally,an example is provided to demonstrate the validity and feasibility of this algorithm.This algorithm not only improves computational efficiency but also provides new perspectives and tools for solving similar network optimization problems.展开更多
The suburbs surrounding metropolitan areas are the priority area for urban-rural integration development where functional optimization is essential to reconcile growing urban demands with sustainable rural development...The suburbs surrounding metropolitan areas are the priority area for urban-rural integration development where functional optimization is essential to reconcile growing urban demands with sustainable rural development.Rural functions are changing substantially and vary significantly across areas in the practice of high-quality urban-rural integration development era.How to make use of the advantages of different rural functions and achieve optimized combination of functions are actual problems that urgently need to be solved.The paper analyzed the process of urban-rural integration through the identification of urban-rural integration interfaces and evaluated the multifunctional transformation of rural areas in the Chengdu-Chongqing Economic Circle(CCEC)with a fixed weight evaluation model.The differences in rural functions analyzed with the Theil index reveals the characteristics and sources of differences in the“production-living-ecology-culture”functional areas in the CCEC.The research results show that:(1)The spatial distribution characteristics of rural functions in the CCEC are obvious,and agricultural production clusters dominate the Chengdu Plain and eastern Chongqing,contrasting with ecological conservation zones along the Yangtze River system,while cultural heritage hubs concentrate in economically vibrant tourism corridors.(2)The overall regional differences in rural functions are mainly due to intra-regional differences;in terms of the contribution rate,the contribution rate of intra-regional differences in agricultural production,ecological conservation,and cultural heritage functions is much larger than that of inter-regional differences,whereas the inter-regional differences in human living functions are larger than those of intra-regional differences.(3)Based on the research results,the study area is divided into 14 functional types,which can provide scientific basis for improving the spatial layout and high-quality development of rural functions in the CCEC.These insights advance theoretical understanding of mountainous-urban transitional areas while informing practical strategies for high-quality integrated development.展开更多
This paper focuses on Chengdu and Chongqing’s positioning as important economic center in western China and their evolving into an economic center of national influence.On the one hand,it uses the synthetic differenc...This paper focuses on Chengdu and Chongqing’s positioning as important economic center in western China and their evolving into an economic center of national influence.On the one hand,it uses the synthetic difference-in-differences(SDID)method to analyze the impact of policies since 2011 designed to build Chengdu and Chongqing into an important economic center in western China.On the other hand,it employs the entropy-weighted TOPSIS method to comprehensively evaluate the influences of ten core Chinese cities as economic centers within four major urban agglomerations,as well as conduct an analytical assessment of the Chengdu-Chongqing economic circle from key perspectives such as its capacity to lead,capacity to agglomerate,and capacity to radiate.From a longitudinal historical perspective,both Chengdu and Chongqing have benefited significantly from policies designed to build an important economic center in western China,and which laid a foundation for building an economic center of national influence.From a horizontal regional comparison,among the ten core cities evaluated as economic centers within the four major urban agglomerations,Chengdu and Chongqing ranked in the middle,possessing a moderate but not yet outstanding influence.Consequently,to evolve into an economic center of national influence,the Chengdu-Chongqing economic circle should leverage its relative advantages in connectivity,market size,value chain division of labor,policy attractiveness,and industry development.It can enhance its influence by strengthening the complementarity of its economic resources,overcoming the administrative inertia,accelerating the establishment of a regional innovation system,broadening the scope of its economic radiation,and promoting its comprehensive and all-dimensional opening-up.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12102186,12032012)the Natural Science Foundation of Jiangsu Province,China(No.BK20200433)+2 种基金the Laboratory Foundation of China(No.61422202201)the Young Elite Scientists Sponsorship Program by CAST,China(No.2022QNRC001)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China。
文摘To investigate the distinct properties of the helicopter rotors during circling flight,the aerodynamic and dynamic models for the main rotor are established considering the trim conditions and the flight parameters of helicopters.The free wake method is introduced to compute the unsteady aerodynamic loads of the rotor characterized by distortions of rotor wakes,and the modal superposition method is used to predict the overall structural loads of the rotor.The effectiveness of the aerodynamic and the structural methods is verified by comparison with the experimental results,whereby the influences of circling direction,radius,and velocity are evaluated in both aerodynamic and dynamic aspects.The results demonstrate that the circling condition makes a great difference to the performance of rotor vortex,as well as the unsteady aerodynamic loads.With the decrease of the circling radius or the increment of the circling velocity,the thrust of the main rotor increases apparently to balance the inertial force.Meanwhile,the harmonics of aerodynamic loads in rotor disc change severely and an evident aerodynamic load shock appears at high-order components,which further causes a shift-of-peak-phase bending moment in the flap dimension.Moreover,the advancing side of blade experiences second blade/vortex interaction,whose intensity has a distinct enhancement as the circling radius decreases with the motion of vortexes.
文摘By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we make aspecial study about centering- point curve and circling- point curve and couplercurves based on Ball’s points.
文摘MPTP (1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine) is a byproduct formed during the synthesis of a meperidine analog. Davis (1979) and Langston (1983) reported a group of drug addicts who developed classical Parkinsonism after self-administration of a mixture containing MPTP, their pathological and biochemical
文摘Prediction of water inflow into a tunnel is a crucial prerequisite for the waterproof and drainage design of mountain tunnels in water-rich areas.Based on the proposed Baiyun Mountain Tunnel project in Guangzhou,a numerical percolation model of random fractured rock of a tunnel underpassing a water reservoir is established to study the seepage characteristics of surrounding rock,the law of water inflow,and the change of lining water pressure,considering the local artificial boundary conditions for seepage in large rock mass,.In addition,the influences of rock permeability,fracture aperture,grouting circle thickness,and penetration are analyzed.The results show that:(1)Only fractures with aperture wider than 0.1 mm can play a significant role in water conduction in rocks with the permeability lower than 10^(-11)m^(2);(2)The greater the permeability difference between the fractures and rocks,the more remarkable the effects of fractures on the surrounding rock seepage field and cavern water inflow;(3)The sensitivity of grouting waterproof function to grouting circle thickness,grouting ring penetration,and rock permeability is significantly higher than that of tunnel buried depth and fracture aperture;(4)The lining water head is much more sensitive to the grouting circle thickness and penetration than to the tunnel buried depth;(5)With the grouting range enlarging,the impact of grouting circle permeability on the precipitation pressure role of the grouting ring increases;(6)For the interesting tunnel designed to be built at the depth of 70 m,the grouting circle with the thickness of 0.5 m and permeability of 10-^(14)m^(2)is recommended.
文摘During the final proofing stage of the paper,the wrong version of Fig.2 was accidently used when replacing it with a high-resolution version.The star and circle marks were missing in the published version.
文摘Objective:To investigate the effectiveness of Quality Control Circle(QCC)activities in reducing the loss rate during storage of Traditional Chinese Medicine(TCM)decoction pieces in our hospital pharmacy department.Methods:A QCC team was established to systematically analyze the causes of TCM decoction piece losses.Using quality improvement tools including Pareto charts,the 80/20 rule,and fishbone diagrams,we identified key areas for improvement and developed targeted intervention strategies.The study period spanned from January to December 2023,with pre-intervention data collected from January to December 2022.Loss rates were calculated and compared before and after QCC implementation.Results:According to the“80/20 rule”analysis,the primary improvement targets were identified as inadequate maintenance of decoction pieces and dispensing losses.Following QCC implementation,the loss rate of TCM decoction pieces decreased significantly from 1.27%(pre-intervention)to 0.65%(post-intervention),achieving an improvement rate of 47.40%.The total monetary loss decreased from 9,592.62 RMB to 4,546.97 RMB.Conclusion:QCC activities can effectively reduce the loss rate of TCM decoction pieces in hospital pharmacy departments,improve the quality of herbal medicines,ensure patient medication safety,and enhance pharmaceutical service quality.This systematic approach provides a valuable framework for continuous quality improvement in TCM pharmacy management.
基金The National Natural Science Foundation of China(No.72001107,72271120)the Fundamental Research Funds for the Central Universities(No.NS2024047,NP2024106)the China Postdoctoral Science Foundation(No.2020T130297,2019M660119).
文摘The presence of circles in the network maximum flow problem increases the complexity of the preflow algorithm.This study proposes a novel two-stage preflow algorithm to address this issue.First,this study proves that at least one zero-flow arc must be present when the flow of the network reaches its maximum value.This result indicates that the maximum flow of the network will remain constant if a zero-flow arc within a circle is removed;therefore,the maximum flow of each network without circles can be calculated.The first stage involves identifying the zero-flow arc in the circle when the network flow reaches its maximum.The second stage aims to remove the zero-flow arc identified and modified in the first stage,thereby producing a new network without circles.The maximum flow of the original looped network can be obtained by solving the maximum flow of the newly generated acyclic network.Finally,an example is provided to demonstrate the validity and feasibility of this algorithm.This algorithm not only improves computational efficiency but also provides new perspectives and tools for solving similar network optimization problems.
基金funded by the National Natural Science Foundation of China(Grant Nos.T2261129477,42101202 and 42401261)Fundamental Research Funds for the Central Universities(2024CDJSKXYGG06)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400528).
文摘The suburbs surrounding metropolitan areas are the priority area for urban-rural integration development where functional optimization is essential to reconcile growing urban demands with sustainable rural development.Rural functions are changing substantially and vary significantly across areas in the practice of high-quality urban-rural integration development era.How to make use of the advantages of different rural functions and achieve optimized combination of functions are actual problems that urgently need to be solved.The paper analyzed the process of urban-rural integration through the identification of urban-rural integration interfaces and evaluated the multifunctional transformation of rural areas in the Chengdu-Chongqing Economic Circle(CCEC)with a fixed weight evaluation model.The differences in rural functions analyzed with the Theil index reveals the characteristics and sources of differences in the“production-living-ecology-culture”functional areas in the CCEC.The research results show that:(1)The spatial distribution characteristics of rural functions in the CCEC are obvious,and agricultural production clusters dominate the Chengdu Plain and eastern Chongqing,contrasting with ecological conservation zones along the Yangtze River system,while cultural heritage hubs concentrate in economically vibrant tourism corridors.(2)The overall regional differences in rural functions are mainly due to intra-regional differences;in terms of the contribution rate,the contribution rate of intra-regional differences in agricultural production,ecological conservation,and cultural heritage functions is much larger than that of inter-regional differences,whereas the inter-regional differences in human living functions are larger than those of intra-regional differences.(3)Based on the research results,the study area is divided into 14 functional types,which can provide scientific basis for improving the spatial layout and high-quality development of rural functions in the CCEC.These insights advance theoretical understanding of mountainous-urban transitional areas while informing practical strategies for high-quality integrated development.
文摘This paper focuses on Chengdu and Chongqing’s positioning as important economic center in western China and their evolving into an economic center of national influence.On the one hand,it uses the synthetic difference-in-differences(SDID)method to analyze the impact of policies since 2011 designed to build Chengdu and Chongqing into an important economic center in western China.On the other hand,it employs the entropy-weighted TOPSIS method to comprehensively evaluate the influences of ten core Chinese cities as economic centers within four major urban agglomerations,as well as conduct an analytical assessment of the Chengdu-Chongqing economic circle from key perspectives such as its capacity to lead,capacity to agglomerate,and capacity to radiate.From a longitudinal historical perspective,both Chengdu and Chongqing have benefited significantly from policies designed to build an important economic center in western China,and which laid a foundation for building an economic center of national influence.From a horizontal regional comparison,among the ten core cities evaluated as economic centers within the four major urban agglomerations,Chengdu and Chongqing ranked in the middle,possessing a moderate but not yet outstanding influence.Consequently,to evolve into an economic center of national influence,the Chengdu-Chongqing economic circle should leverage its relative advantages in connectivity,market size,value chain division of labor,policy attractiveness,and industry development.It can enhance its influence by strengthening the complementarity of its economic resources,overcoming the administrative inertia,accelerating the establishment of a regional innovation system,broadening the scope of its economic radiation,and promoting its comprehensive and all-dimensional opening-up.
