A new synchronization scheme for chaotic（hyperchaotic） maps with different dimensions is presented.Specifically,given a drive system map with dimension n and a response system with dimension m,the proposed approach ...A new synchronization scheme for chaotic（hyperchaotic） maps with different dimensions is presented.Specifically,given a drive system map with dimension n and a response system with dimension m,the proposed approach enables each drive system state to be synchronized with a linear response combination of the response system states.The method,based on the Lyapunov stability theory and the pole placement technique,presents some useful features：（i） it enables synchronization to be achieved for both cases of n 〈 m and n 〉 m;（ii） it is rigorous,being based on theorems;（iii） it can be readily applied to any chaotic（hyperchaotic） maps defined to date.Finally,the capability of the approach is illustrated by synchronization examples between the two-dimensional H′enon map（as the drive system） and the three-dimensional hyperchaotic Wang map（as the response system）,and the three-dimensional H′enon-like map（as the drive system） and the two-dimensional Lorenz discrete-time system（as the response system）.展开更多
This paper deals with the fixed-time adaptive time-varying matrix projective synchronization(ATVMPS)of different dimensional chaotic systems(DDCSs)with time delays and unknown parameters.Firstly,to estimate the unknow...This paper deals with the fixed-time adaptive time-varying matrix projective synchronization(ATVMPS)of different dimensional chaotic systems(DDCSs)with time delays and unknown parameters.Firstly,to estimate the unknown parameters,adaptive parameter updated laws are designed.Secondly,to realize the fixed-time ATVMPS of the time-delayed DDCSs,an adaptive delay-unrelated controller is designed,where time delays of chaotic systems are known or unknown.Thirdly,some simple fixed-time ATVMPS criteria are deduced,and the rigorous proof is provided by employing the inequality technique and Lyapunov theory.Furthermore,the settling time of fixed-time synchronization(Fix-TS)is obtained,which depends only on controller parameters and system parameters and is independent of the system’s initial states.Finally,simulation examples are presented to validate the theoretical analysis.展开更多
Objective: to explore the health status of long-term care and its influence on self-care ability. Methods: selected 40 elderly people receiving long-term care, from March 2019 to August 2021, investigated the general ...Objective: to explore the health status of long-term care and its influence on self-care ability. Methods: selected 40 elderly people receiving long-term care, from March 2019 to August 2021, investigated the general data, health status of various dimensions, and self-care ability, and correlation analysis. Results: the care score of the elderly was influenced by age, marital status and pension mode, P 0.05, physical function and psychological cognition were P 0.05, and the multi-term analysis included language ability, pension mode, cognitive status and health, P 0.05. Conclusion: the health status of long-term care of the elderly is poor, and their self-care ability is affected by various factors, including language ability, pension mode, cognitive status, and self-evaluation of health. Targeted measures should be taken as soon as possible to ensure the health status and self-care ability of the elderly.展开更多
The chief objective of the article is to learn the spatial characteristics of stress distribution around a shallow buried cylinder Karst cave in limestone strata.Firstly,taking into account the geometry of limestone f...The chief objective of the article is to learn the spatial characteristics of stress distribution around a shallow buried cylinder Karst cave in limestone strata.Firstly,taking into account the geometry of limestone formations,and the characteristics of Karst geomorphology in China,a spatial axialsymmetrical hollow model was established.Concurrently,combining available work and the concept of elasticity,the boundary conditions are determined.Subsequently,Love displacement method was introduced,the expressions of stress components were gained.The diagram characteristics of each stress component are summarized,which are affected by various influencing factors.Finally,in order to prove the rationality of the general solution,numerical simulation was carried out on the basis of practical engineering,and the maximum error is less than 5%.Thus,the analytical solution could represent the spatial characteristics of stress distribution around a shallow buried cylinder Karst cave in limestone strata.展开更多
The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the ...The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the turbulent coherent structure in the channel flow. Th is method contains three dimensional coupling difference scheme with high accur acy and high resolution, and the high order time splitting methods. Compared with the general spectral method, the method can be used to research turbule nt coherent structure under more general boundary conditions and in flow domains . In this paper, the generation and evolution of the turbulent coherent structur es ind uced by wall pulse in the channel flow are simulated, and the basic characterist ics and rules of the turbulent coherent structure are shown. Computational r esults indicate that a wall negative pulse is more convenient than the resonant three wave model.展开更多
Megacities serve as global centers for economic,cultural,and high-tech industries.The structural features and population agglomerations are typical traits of urbanization,yet little is known about the morphological fe...Megacities serve as global centers for economic,cultural,and high-tech industries.The structural features and population agglomerations are typical traits of urbanization,yet little is known about the morphological features and expansion patterns of megacities worldwide.Here we examined the spatiotemporal variations of urban land in megalopolises from 2000 to 2020 using the Urban Expansion Intensity Differentiation Index.The fractal features and expansion patterns of megacities were analyzed using the Area-Radius Multi-dimensional Scaling Model.Urban land use efficiency was then evaluated based on the linear relationship between urban land area and population.We found that Southeast Asia and China were the hotspots of urban expansion in megacities from 2000 to 2020,with urban land areas expanding by 3148.32 km^(2)and 5996.26 km^(2),respectively.The morphological features and expansion patterns of megacities exhibited a growing trend towards intensification and compactness,with the average radial dimension increasing from 1.54 to 1.56.The annual decrease in fractal dimensions indicated the integration of inner urban areas.North America and Europe megacities showed a low urban land use efficiency,with a ratio of urban land area to population ranging from 0.89 to 4.11 in 2020.Conversely,South Asia and Africa megacities exhibited a high urban land use efficiency,with the ratios between 0.23 and 0.87.Our results provide information for promoting efficient urban land utilization and sustainable cities.It is proposed to control the scale of urban expansion and to promote balanced development between inner and outer urban areas for achieving resilient and sustainable urban development.展开更多
In this paper,the author first establishes the general finite difference formula for the governing equations of the turbulent average velocities in a steady two dimensional incompressible fluid boundary layer-inner la...In this paper,the author first establishes the general finite difference formula for the governing equations of the turbulent average velocities in a steady two dimensional incompressible fluid boundary layer-inner layer.Next, three key parameters of the difference scheme are determined respectively by several simple flow models with known analytical solutions.Finally a special five points difference system is given and its application value is showed by a numerical example for the vertical velocity distribution in an Ekman's layer.展开更多
The weight hierarchy of a linear[n;k;q]code C over GF(q) is the sequence(d_1,d_2,…,d_k)where d_r is the smallest support of any r-dimensional subcode of C. "Determining all possible weight hierarchies of general...The weight hierarchy of a linear[n;k;q]code C over GF(q) is the sequence(d_1,d_2,…,d_k)where d_r is the smallest support of any r-dimensional subcode of C. "Determining all possible weight hierarchies of general linear codes" is a basic theoretical issue and has important scientific significance in communication system.However,it is impossible for g-ary linear codes of dimension k when q and k are slightly larger,then a reasonable formulation of the problem is modified as: "Determine almost all weight hierarchies of general g-ary linear codes of dimension k".In this paper,based on the finite projective geometry method,the authors study g-ary linear codes of dimension 5 in class IV,and find new necessary conditions of their weight hierarchies,and classify their weight hierarchies into6 subclasses.The authors also develop and improve the method of the subspace set,thus determine almost all weight hierarchies of 5-dimensional linear codes in class IV.It opens the way to determine the weight hierarchies of the rest two of 5-dimensional codes(classes III and VI),and break through the difficulties.Furthermore,the new necessary conditions show that original necessary conditions of the weight hierarchies of k-dimensional codes were not enough(not most tight nor best),so,it is important to excogitate further new necessary conditions for attacking and solving the fc-dimensional problem.展开更多
A conservative difference scheme is presented for the initial-boundary-value problem of a generalized Zakharov equations. On the basis of a prior estimates in L-2 norm, the convergence of the difference solution is pr...A conservative difference scheme is presented for the initial-boundary-value problem of a generalized Zakharov equations. On the basis of a prior estimates in L-2 norm, the convergence of the difference solution is proved in order O(h(2) + r(2)). In the proof, a new skill is used to deal with the term of difference quotient (e(j,k)(n))t. This is necessary, since there is no estimate of E(x, y, t) in L-infinity norm.展开更多
Microporous organic polymers(MOPs) have attracted considerable research interest because of their well-defined porosity,high surface area, lightweight nature, and tunable surface chemistry. The morphology of MOPs are ...Microporous organic polymers(MOPs) have attracted considerable research interest because of their well-defined porosity,high surface area, lightweight nature, and tunable surface chemistry. The morphology of MOPs are demonstrated to play a significant role in various applications although limited examples manifesting the importance of the MOP morphology in numerous applications have been reported. This review summarizes the recent progress in the design of MOPs using different techniques, including hard and soft template and direct synthesis methods. In addition, their applications, which possibly attribute to their shape, are discussed. Furthermore, the advantages and disadvantages of different methods are discussed, as well as their development and future challenges.展开更多
文摘A new synchronization scheme for chaotic（hyperchaotic） maps with different dimensions is presented.Specifically,given a drive system map with dimension n and a response system with dimension m,the proposed approach enables each drive system state to be synchronized with a linear response combination of the response system states.The method,based on the Lyapunov stability theory and the pole placement technique,presents some useful features：（i） it enables synchronization to be achieved for both cases of n 〈 m and n 〉 m;（ii） it is rigorous,being based on theorems;（iii） it can be readily applied to any chaotic（hyperchaotic） maps defined to date.Finally,the capability of the approach is illustrated by synchronization examples between the two-dimensional H′enon map（as the drive system） and the three-dimensional hyperchaotic Wang map（as the response system）,and the three-dimensional H′enon-like map（as the drive system） and the two-dimensional Lorenz discrete-time system（as the response system）.
基金supported by the National Natural Science Foundation of China under Grant 61977004.This support is gratefully acknowledged.
文摘This paper deals with the fixed-time adaptive time-varying matrix projective synchronization(ATVMPS)of different dimensional chaotic systems(DDCSs)with time delays and unknown parameters.Firstly,to estimate the unknown parameters,adaptive parameter updated laws are designed.Secondly,to realize the fixed-time ATVMPS of the time-delayed DDCSs,an adaptive delay-unrelated controller is designed,where time delays of chaotic systems are known or unknown.Thirdly,some simple fixed-time ATVMPS criteria are deduced,and the rigorous proof is provided by employing the inequality technique and Lyapunov theory.Furthermore,the settling time of fixed-time synchronization(Fix-TS)is obtained,which depends only on controller parameters and system parameters and is independent of the system’s initial states.Finally,simulation examples are presented to validate the theoretical analysis.
文摘Objective: to explore the health status of long-term care and its influence on self-care ability. Methods: selected 40 elderly people receiving long-term care, from March 2019 to August 2021, investigated the general data, health status of various dimensions, and self-care ability, and correlation analysis. Results: the care score of the elderly was influenced by age, marital status and pension mode, P 0.05, physical function and psychological cognition were P 0.05, and the multi-term analysis included language ability, pension mode, cognitive status and health, P 0.05. Conclusion: the health status of long-term care of the elderly is poor, and their self-care ability is affected by various factors, including language ability, pension mode, cognitive status, and self-evaluation of health. Targeted measures should be taken as soon as possible to ensure the health status and self-care ability of the elderly.
基金supported by National Natural Science Foundation of China(42002293,52068019)Hainan Provincial Natural Science Foundation of China(520QN229,422RC599)+2 种基金Independent Innovation Fund Project of Tianjin University and Hainan University(KF2022⁃03)Scientific Research Startup Foundation of Hainan university(KYQD(2R)1969)Systematic Project of Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(Three Gorges University),Ministry of Education(2020KDZ04).
文摘The chief objective of the article is to learn the spatial characteristics of stress distribution around a shallow buried cylinder Karst cave in limestone strata.Firstly,taking into account the geometry of limestone formations,and the characteristics of Karst geomorphology in China,a spatial axialsymmetrical hollow model was established.Concurrently,combining available work and the concept of elasticity,the boundary conditions are determined.Subsequently,Love displacement method was introduced,the expressions of stress components were gained.The diagram characteristics of each stress component are summarized,which are affected by various influencing factors.Finally,in order to prove the rationality of the general solution,numerical simulation was carried out on the basis of practical engineering,and the maximum error is less than 5%.Thus,the analytical solution could represent the spatial characteristics of stress distribution around a shallow buried cylinder Karst cave in limestone strata.
文摘The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the turbulent coherent structure in the channel flow. Th is method contains three dimensional coupling difference scheme with high accur acy and high resolution, and the high order time splitting methods. Compared with the general spectral method, the method can be used to research turbule nt coherent structure under more general boundary conditions and in flow domains . In this paper, the generation and evolution of the turbulent coherent structur es ind uced by wall pulse in the channel flow are simulated, and the basic characterist ics and rules of the turbulent coherent structure are shown. Computational r esults indicate that a wall negative pulse is more convenient than the resonant three wave model.
基金The Strategic Priority Research Program of Chinese Academy of Sciences,No.XDA20040403,No.XDA23100201。
文摘Megacities serve as global centers for economic,cultural,and high-tech industries.The structural features and population agglomerations are typical traits of urbanization,yet little is known about the morphological features and expansion patterns of megacities worldwide.Here we examined the spatiotemporal variations of urban land in megalopolises from 2000 to 2020 using the Urban Expansion Intensity Differentiation Index.The fractal features and expansion patterns of megacities were analyzed using the Area-Radius Multi-dimensional Scaling Model.Urban land use efficiency was then evaluated based on the linear relationship between urban land area and population.We found that Southeast Asia and China were the hotspots of urban expansion in megacities from 2000 to 2020,with urban land areas expanding by 3148.32 km^(2)and 5996.26 km^(2),respectively.The morphological features and expansion patterns of megacities exhibited a growing trend towards intensification and compactness,with the average radial dimension increasing from 1.54 to 1.56.The annual decrease in fractal dimensions indicated the integration of inner urban areas.North America and Europe megacities showed a low urban land use efficiency,with a ratio of urban land area to population ranging from 0.89 to 4.11 in 2020.Conversely,South Asia and Africa megacities exhibited a high urban land use efficiency,with the ratios between 0.23 and 0.87.Our results provide information for promoting efficient urban land utilization and sustainable cities.It is proposed to control the scale of urban expansion and to promote balanced development between inner and outer urban areas for achieving resilient and sustainable urban development.
文摘In this paper,the author first establishes the general finite difference formula for the governing equations of the turbulent average velocities in a steady two dimensional incompressible fluid boundary layer-inner layer.Next, three key parameters of the difference scheme are determined respectively by several simple flow models with known analytical solutions.Finally a special five points difference system is given and its application value is showed by a numerical example for the vertical velocity distribution in an Ekman's layer.
基金supported by the National Natural Science Foundation of China under Grant No.11171366"the Fundamental Research Funds for the Central Universities"South-Central University for Nationalities under Grant No.CZY12014
文摘The weight hierarchy of a linear[n;k;q]code C over GF(q) is the sequence(d_1,d_2,…,d_k)where d_r is the smallest support of any r-dimensional subcode of C. "Determining all possible weight hierarchies of general linear codes" is a basic theoretical issue and has important scientific significance in communication system.However,it is impossible for g-ary linear codes of dimension k when q and k are slightly larger,then a reasonable formulation of the problem is modified as: "Determine almost all weight hierarchies of general g-ary linear codes of dimension k".In this paper,based on the finite projective geometry method,the authors study g-ary linear codes of dimension 5 in class IV,and find new necessary conditions of their weight hierarchies,and classify their weight hierarchies into6 subclasses.The authors also develop and improve the method of the subspace set,thus determine almost all weight hierarchies of 5-dimensional linear codes in class IV.It opens the way to determine the weight hierarchies of the rest two of 5-dimensional codes(classes III and VI),and break through the difficulties.Furthermore,the new necessary conditions show that original necessary conditions of the weight hierarchies of k-dimensional codes were not enough(not most tight nor best),so,it is important to excogitate further new necessary conditions for attacking and solving the fc-dimensional problem.
文摘A conservative difference scheme is presented for the initial-boundary-value problem of a generalized Zakharov equations. On the basis of a prior estimates in L-2 norm, the convergence of the difference solution is proved in order O(h(2) + r(2)). In the proof, a new skill is used to deal with the term of difference quotient (e(j,k)(n))t. This is necessary, since there is no estimate of E(x, y, t) in L-infinity norm.
基金supported by the National Natural Science Foundation of China(21474033)the International Science and Technology Cooperation Program of China(2016YFE0124400)the Program for Huazhong University of Science and Technology Interdisciplinary Innovation Team(2016JCTD104)
文摘Microporous organic polymers(MOPs) have attracted considerable research interest because of their well-defined porosity,high surface area, lightweight nature, and tunable surface chemistry. The morphology of MOPs are demonstrated to play a significant role in various applications although limited examples manifesting the importance of the MOP morphology in numerous applications have been reported. This review summarizes the recent progress in the design of MOPs using different techniques, including hard and soft template and direct synthesis methods. In addition, their applications, which possibly attribute to their shape, are discussed. Furthermore, the advantages and disadvantages of different methods are discussed, as well as their development and future challenges.
