In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrabilit...In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.展开更多
This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expan...This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expansion with environmental protection,a comprehensive evaluation index system is constructed,encompassing two key dimensions:regional economy and ecological environment.Using panel data from 2013 to 2022,the coupling coordination degree model is employed to quantify the interactions and synergy between these dimensions.Additionally,spatial econometric methods are applied to calculate both global and local Moran’s Index,revealing spatial clustering patterns,regional disparities,and heterogeneity.The relative development model further identifies critical factors influencing regional coordination,with a focus on the lagging development of basic infrastructure and public services.The findings demonstrate a positive temporal trend toward improved regional coordination and reduced development gaps,with a spatial pattern characterized by higher coupling degrees in eastern and central regions compared to western areas.Based on these results,this study proposes actionable strategies to enhance coordinated development,emphasizing ecological conservation,the establishment of green production and consumption systems,ecological restoration,and strengthened municipal collaboration.This revised abstract emphasizes the study’s purpose,methods,and key findings more clearly while maintaining a professional and concise tone.Finally,based on the above analysis results,the corresponding coordinated development suggestions of regional economy and ecological environment are given from the aspects of ecological environment protection measures,green production and consumption system construction,ecological environment restoration and municipal coordination.展开更多
The gear transmission system directly affects the operational performance of high-speed trains(HST).However,current research on gear transmission systems of HST often overlooks the effects of gear eccentricity and run...The gear transmission system directly affects the operational performance of high-speed trains(HST).However,current research on gear transmission systems of HST often overlooks the effects of gear eccentricity and running resistance,and the dynamic models of gear transmission system are not sufficiently comprehensive.This paper aims to establish an electromechanical coupling dynamic model of HST traction transmission system and study its electromechanical coupling vibration characteristics,in which the internal excitation factors such as gear eccentricity,time-varying meshing stiffness,backlash,meshing error,and external excitation factors such as electromagnetic torque and running resistance are stressed.The research results indicate that gear eccentricity and running resistance have a significant impact on the stability of the system,and gear eccentricity leads to intensified system vibration and decreased anti-interference ability.In addition,the characteristic frequency of gear eccentricity can be extracted from mechanical signals and current signals as a preliminary basis for eccentricity detection,and electrical signals can also be used to monitor changes in train running resistance in real time.The results of this study provide some useful insights into designing dynamic performance parameters for HST transmission systems and monitoring train operational states.展开更多
Ground source heat pump systems demonstrate significant potential for northern rural heating applications;however,the effectiveness of these systems is often limited by challenging geological conditions.For instance,i...Ground source heat pump systems demonstrate significant potential for northern rural heating applications;however,the effectiveness of these systems is often limited by challenging geological conditions.For instance,in certain regions,the installation of buried pipes for heat exchangers may be complicated,and these pipes may not always serve as efficient low-temperature heat sources for the heat pumps of the system.To address this issue,the current study explored the use of solar-energy-collecting equipment to supplement buried pipes.In this design,both solar energy and geothermal energy provide low-temperature heat to the heat pump.First,a simulation model of a solar‒ground source heat pump coupling system was established using TRNSYS.The accuracy of this model was validated through experiments and simulations on various system configurations,including varying numbers of buried pipes,different areas of solar collectors,and varying volumes of water tanks.The simulations examined the coupling characteristics of these components and their influence on system performance.The results revealed that the operating parameters of the system remained consistent across the following configurations:three buried pipes,burial depth of 20 m,collector area of 6 m^(2),and water tank volume of 0.5 m^(3);four buried pipes,burial depth of 20 m,collector area of 3 m^(2),and water tank volume of 0.5 m^(3);and five buried pipes with a burial depth of 20 m.Furthermore,the heat collection capacity of the solar collectors spanning an area of 3 m^(2)was found to be equivalent to that of one buried pipe.Moreover,the findings revealed that the solar‒ground source heat pump coupling system demonstrated a lower annual cumulative energy consumption compared to the ground source heat pump system,presenting a reduction of 5.31%compared to the energy consumption of the latter.展开更多
Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an u...Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an urgent need for innovative research frameworks.Integrated geography synthesizes physical geography,human geography,and geographic information science,providing key frameworks for understanding complex human-environment systems.This editorial proposes an emerging research framework for integrated geography—“Composite driving-System evolution-Coupling mechanism-Synergistic regulation(CSCS)”—based on key issues such as climate change,biodiversity loss,resource scarcity,and social-ecological interactions,which have been highlighted in both recent critical literature on human-environment systems and UN assessment reports.The framework starts with diverse composite driving forces,extends to the evolution of human-environment system structures,processes,and functions that these drivers induce,explores couplings within human-environment systems,and calls for regulation aimed at sustainable development in synergies.Major research frontiers include understanding the cascading“evolution-coupling”effects of shocks;measuring system resilience,thresholds,and safe and just operating space boundaries;clarifying linkage mechanisms across scales;and achieving synergistic outcomes for multi-objective sustainability.This framework will help promote the interdisciplinary integration and development of integrated geography,and provide geographical solutions for the global sustainable development agenda.展开更多
The park-level integrated energy system(PIES)is essential for achieving carbon neutrality by managing multi-energy supply and demand while enhancing renewable energy integration.However,current carbon trading mechanis...The park-level integrated energy system(PIES)is essential for achieving carbon neutrality by managing multi-energy supply and demand while enhancing renewable energy integration.However,current carbon trading mechanisms lack sufficient incentives for emission reductions,and traditional optimization algorithms often face challenges with convergence and local optima in complex PIES scheduling.To address these issues,this paper introduces a low-carbon dispatch strategy that combines a reward-penalty tiered carbon trading model with P2G-CCS integration,hydrogen utilization,and the Secretary Bird Optimization Algorithm(SBOA).Key innovations include:(1)A dynamic reward-penalty carbon trading mechanism with coefficients(μ=0.2,λ=0.15),which reduces carbon trading costs by 47.2%(from$694.06 to$366.32)compared to traditional tiered models,incentivizing voluntary emission reductions.(2)The integration of P2G-CCS coupling,which lowers natural gas consumption by 41.9%(from$4117.20 to$2389.23)and enhances CO_(2) recycling efficiency,addressing the limitations of standalone P2G or CCS technologies.(3)TheSBOA algorithm,which outperforms traditionalmethods(e.g.,PSO,GWO)in convergence speed and global search capability,avoiding local optima and achieving 24.39%faster convergence on CEC2005 benchmark functions.(4)A four-energy PIES framework incorporating electricity,heat,gas,and hydrogen,where hydrogen fuel cells and CHP systems improve demand response flexibility,reducing gas-related emissions by 42.1%and generating$13.14 in demand response revenue.Case studies across five scenarios demonstrate the strategy’s effectiveness:total operational costs decrease by 14.7%(from$7354.64 to$6272.59),carbon emissions drop by 49.9%(from 5294.94 to 2653.39kg),andrenewable energyutilizationincreases by24.39%(from4.82%to8.17%).These results affirmthemodel’s ability to reconcile economic and environmental goals,providing a scalable approach for low-carbon transitions in industrial parks.展开更多
This study theoretically investigates chaos in a cavity optomechanical system with Coulomb coupling.The system consists of a Fabry-Pérot cavity with a movable mirror,where Coulomb interactions arise from charging...This study theoretically investigates chaos in a cavity optomechanical system with Coulomb coupling.The system consists of a Fabry-Pérot cavity with a movable mirror,where Coulomb interactions arise from charging the two movable mirrors.We examine the chaotic dynamics under the influence of both single and bichromatic laser fields.The single laser field represents a system driven exclusively by the pump field,whereas the bichromatic field represents simultaneous driving by both the pump and probe fields.In addition to conventional chaos-inducing methods through parameter variations,we demonstrate that increasing the Coulomb coupling strength enhances the system’s nonlinearity and induces chaotic behavior.Furthermore,we propose several strategies for generating and controlling chaos,while also identifying the parameter ranges necessary for the resonance of the two mechanical oscillators.Interestingly,when adjusting the driving power in a system driven solely by the pump field,we unexpectedly observe the emergence of high-order sidebands.These findings contribute to the development of chaotic behavior in future cavity optomechanical systems and provide a theoretical basis for applications in physical random number generation and secure communication.展开更多
The circuit quantum electrodynamics(QED)system has brought us into an ultrastrong and deep coupling regime in the light-matter interaction community,in which the quantum effect has attracted significant interest.In th...The circuit quantum electrodynamics(QED)system has brought us into an ultrastrong and deep coupling regime in the light-matter interaction community,in which the quantum effect has attracted significant interest.In this study,we theoretically investigated the photon blockade phenomenon in a double-transmon system operating in an ultrastrong coupling regime.We considered the effect of the counter-rotating wave terms in the interaction Hamiltonian and derived the master equation in the eigenpresentation.We found that photon blockade occurred in only one of the eigenmodes,and the counter-rotating wave terms enhanced the blockade by reducing the minimum value of the second-order correlation function.This study will be beneficial for the design of single-photon devices in circuit QED systems,especially in the ultrastrong coupling regime.展开更多
The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivativ...The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivative operator.Additionally,time delays in the potential field force and coupling force transmission are both considered.Firstly,based on the delay decoupling formula,combined with statistical mean method and the fractional-order Shapiro–Loginov formula,the“statistic synchronization”among particles is obtained,revealing the statistical equivalence between the mean field behavior of the system and the behavior of individual particles.Due to the existence of the coupling delay,the impact of the coupling force on synchronization exhibits non-monotonic,which is different from the previous monotonic effects.Then,two kinds of theoretical expression of output amplitude gains G and G are derived by time-delay decoupling formula and small delay approximation theorem,respectively.Compared to G,G is an exact theoretical solution,which means that G is not only more accurate in the region of small delay,but also applies to the region of large delay.Finally,the study of the output amplitude gain G and its resonance behavior are explored.Due to the presence of the potential field delay,a new resonance phenomenon termed“periodic resonance”is discovered,which arises from the periodic matching between the potential field delay and the driving frequency.This resonance phenomenon is analyzed qualitatively and quantitatively,uncovering undiscovered characteristics in previous studies.展开更多
This article discusses the detailed examination of the engineering design and implementation process for direct Train-to-Train(T2T)communication within a wireless train backbone network in the context of a virtual cou...This article discusses the detailed examination of the engineering design and implementation process for direct Train-to-Train(T2T)communication within a wireless train backbone network in the context of a virtual coupling scenario.The article proposed several critical aspects,including the optimization of transmission data requirements,which is essential to ensure that communication between trains is efficient and reliable.The design of the T2T wireless communication subsystem is discussed in detail,outlining the technical specifications,protocols,and technologies employed to facilitate wireless communication between multiple trains.Additionally,the article presents a thorough analysis of the data collected during real-world train experiments,highlighting the performance metrics and challenges encountered during testing.This empirical data not only validates the effectiveness of the proposed design but also serves as a crucial reference for future advancements in T2T wireless communication systems.By combining both theoretical principles and practical outcomes,the article offers insights that will aid engineers and researchers in developing robust and efficient wireless communication systems for next-generation train operations.展开更多
Ecosystem service flows(ESFs)can reveal the interrelationships and impacts between natural systems and human activities.We can improve the stability and sustainability of ecosystems,more effectively utilize natural re...Ecosystem service flows(ESFs)can reveal the interrelationships and impacts between natural systems and human activities.We can improve the stability and sustainability of ecosystems,more effectively utilize natural resources,protect the environment,and enhance the harmonious coexistence of humans and nature by comprehending ESFs.However,few studies have examined ESFs across scales and evaluated their sustainability;most have concentrated on regional scales.In order to quantify and analyze ESFs within the Jing River Basin(JRB)and between the JRB and the adjacent and distant regions from a water-food-energy perspective,this paper employs a meta-coupling framework.Additionally,it evaluates the sustainability of these flows using a techno-ecological synergy framework.The results show that the ESFs within the JRB was significant in 2020.Water production services were concentrated in the southern part of the JRB,while the distribution of food supply and carbon supply services was relatively even.Huan County emerged as the largest exporting county,providing 1.46×10^(8)kg of food to other counties and exporting 2.97×10^(6)kg of energy.The ESFs in the JRB primarily moved towards the neighboring and distant systems.Water production services flowed into the Guanzhong Plain Urban Agglomeration(GPUA),amounting to 5.8×10^(6)kg.Carbon supply services flowed out at 2.4×10^(5)kg,and food exports were the highest,reaching 5.0×10^(7)kg.The ecosystem service flows from the JRB to both the neighboring and distant systems enhanced food security and ecological resilience.The basin itself demonstrated good sustainability in food supply services,with an index value reaching 48.19.In crossscale calculations of food production sustainability with the adjacent GPUA,the index value increased from 48.19 to 52.99,indicating a significant improvement.These findings demonstrate that applying the meta-coupling framework provides an effective approach to quantify ESFs and assess their sustainability across scales.展开更多
A hydrophobic composite coating was obtained on the carbon steel surface through electrochemical deposition of a copper coating in a sulfate solution and chemical vapor deposition of a carbon fiber film.It alleviated ...A hydrophobic composite coating was obtained on the carbon steel surface through electrochemical deposition of a copper coating in a sulfate solution and chemical vapor deposition of a carbon fiber film.It alleviated the serious corrosion problem of carbon steel on the evaporator of hot film coupled seawater desalination system in harsh marine environment.The morphologies and compositions of the coatings were analyzed,revealing the influence of electrodeposition time on their performance.The micro-nano copper structure formed by electrodeposition significantly improved the deposition effect of carbon layer.Additionally,experiments with seawater solution contact angle tests indicated that electrodeposition transformed the surface properties from hydrophilic to hydrophobic,effectively inhibiting the diffusion of corrosive medium into the interior of the substrate.Through polarization curves,electrochemical impedance spectroscopy,and other analyses,it was demonstrated that the hydrophobic coating significantly improves the corrosion resistance of carbon steel substrates in seawater environments,surpassing the performance of traditional duplex steel.展开更多
Under the“dual carbon”goals,this paper constructs an optimization model of the comprehensive energy system in the park.A stepwise carbon excess rate mechanism and an electric vehicle coupling strategy are proposed:A...Under the“dual carbon”goals,this paper constructs an optimization model of the comprehensive energy system in the park.A stepwise carbon excess rate mechanism and an electric vehicle coupling strategy are proposed:A carbon quota trading system is established based on the baseline method,and the stepwise function is adopted to quantify the cost of excess carbon emissions;Introduce the price demand response and the two-way interaction mechanism of electric Vehicle vehicle-to-grid(V2G)to enhance the flexible regulation ability.Aiming at the uncertainty of wind and solar output,a typical scene set is generated by combining Latin hypercube sampling with the scene reduction method.The goal is to minimize the operating cost and maximize the consumption of renewable energy,and it is solved through the CPLEX solver in the MATLAB platform.Through simulation verification of the proposed models and methods in various scenarios,the simulation results show that under the coupling of the carbon excess rate trading mechanism,the demand response mechanism,and the vehicle-to-grid interaction of electric vehicles,the total daily operating cost of the system decreases by 25.3%,reduce the dual pressure of energy consumption costs and the economic environment,and achieve the coordinated optimization of economic and ecological benefits.展开更多
Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental ...Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental investigation is important in correlating the catalytic activity and the products.In this work,a spatial resolution online mass spectrometry(MS)system was developed and applied to a Mn-Na_(2)WO_(4)/SiO_(2) catalyzed OCM system.In addition to the residue gas analysis,the system obtained the distribution information of the reactants and products in the reactor.At various setting temperatures,all species online MS signals were collected at different positions,mapping the reaction activity covering parameters including temperature,time and space.The distribution behavior of the catalytic activity,selectivity,and apparent activation energy were kinetically analyzed.Selectivity and additional carbon balance analysis strongly supported the radical coupling model of OCM and indicated that after the catalytic bed layer,there is a significant length in the reactor(>2 mm)filled with radicals.Based on the result,a designed new method by tuning the temperature field in the reactor was found effectively to improve the catalytic activity,especially the C_(2) yield from 702 to 773℃.展开更多
In Earth system modeling,the land surface is coupled with the atmosphere through surface turbulent fluxes.These fluxes are computed using mean meteorological variables between the surface and a reference height in the...In Earth system modeling,the land surface is coupled with the atmosphere through surface turbulent fluxes.These fluxes are computed using mean meteorological variables between the surface and a reference height in the atmosphere.However,the dependence of flux computation on the reference height,which is usually set as the lowest level in the atmosphere in Earth system models,has not received much attention.Based on high-resolution large-eddy simulation(LES)data under unstable conditions,we find the setting of reference height is not trivial within the framework of current surface layer theory.With a reasonable prescription of aerodynamic roughness length(following the setting in LESs),reference heights near the top of the surface layer tend to provide the best estimate of surface fluxes,especially for the momentum flux.Furthermore,this conclusion for the sensible heat flux is insensitive to the ratio of roughness length for momentum versus heat.These results are robust,whether using the classical or revised surface layer theory.They provide a potential guide for setting the proper reference heights for Earth system modeling and can be further tested in the near future using observational data from land–atmosphere feedback observatories.展开更多
The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-domin...The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.展开更多
During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wh...During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wheels,and the wheelsets will seriously affect the stability of the grinding force.In this paper,the coupled mechanical model of the grinding wheel/rail is established based on the contact mechanics theory,which is embedded as a submodel into the dynamic model of the multi-rigid buggy.The interaction among the frame,the grinding wheels and the wheelsets is analysed by setting the convex irregularity on the rail.The grinding effect is evaluated in combination with the subway’s long wave corrugation grinding conditions.The results show that when the grinding buggy passes the convex irregularity,the vibration excited by the wheelset system has a significant impact on the dynamic behavior of the grinding wheels.The vibration of the grinding wheel is mainly transmitted between the grinding wheel and the frame,less affecting the wheelset.For the long wave corrugation of the subway,the grinding effect of the grinding wheel has a certain correlation with the phase angle of the wheelset through the corrugation.The research results provide an important reference for the setting of the grinding pattern.展开更多
A general scheme for generating a multi-component integrable equation hierarchy is proposed. A simple 3M- dimensional loop algebra ~X is produced. By taking advantage of ~X a new isospectral problem is established and...A general scheme for generating a multi-component integrable equation hierarchy is proposed. A simple 3M- dimensional loop algebra ~X is produced. By taking advantage of ~X a new isospectral problem is established and then by making use of the Tu scheme the multi-component Dirac equation hierarchy is obtained. Finally, an expanding loop algebra ~FM of the loop algebra ~X is presented. Based on the ~FM, the multi-component integrable coupling system of the multi-component Dirac equation hierarchy is investigated. The method in this paper can be applied to other nonlinear evolution equation hierarchies.展开更多
In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses...In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses and strong disturbances and construction conditions such as the application of high prestress.It is essential to study the support components performance under dynamic-static coupling conditions.Based on this,a multi-functional anchorage support dynamic-static coupling performance test system(MAC system)is developed,which can achieve 7 types of testing functions,including single component performance,anchored net performance,anchored rock performance and so on.The bolt and cable mechanical tests are conducted by MAC system under different prestress levels.The results showed that compared to the non-prestress condition,the impact resistance performance of prestressed bolts(cables)is significantly reduced.In the prestress range of 50–160 k N,the maximum reduction rate of impact energy resisted by different types of bolts is 53.9%–61.5%compared to non-prestress condition.In the prestress range of 150–300 k N,the impact energy resisted by high-strength cable is reduced by76.8%–84.6%compared to non-prestress condition.The MAC system achieves dynamic-static coupling performance test,which provide an effective means for the design of anchorage support system.展开更多
We propose a systematic method for generalizing the integrable couplings of soliton eqhations hierarchy with self-consistent sources associated with s/（4）. The JM equations hierarchy with self-consistent sources is ...We propose a systematic method for generalizing the integrable couplings of soliton eqhations hierarchy with self-consistent sources associated with s/（4）. The JM equations hierarchy with self-consistent sources is derived. Furthermore, an integrable couplings of the JM soliton hierarchy with self-consistent sources is presented by using of the loop algebra sl（4）.展开更多
基金sponsored by the National Natural Science Foundations of China under Grant Nos.12301315,12235007,11975131the Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ20A010009。
文摘In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.
基金support from Guangdong Science and Technology(20230505)Guangdong Provincial Philosophy and Social Science Planning Project(GD20SQ25)Guangdong Provincial Special Fund for Science and Technology Innovation Strategy in 2024(Cultivation of College Students’Science and Technology Innovation)(pdjh2024a391)during preparation of this manuscript.
文摘This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expansion with environmental protection,a comprehensive evaluation index system is constructed,encompassing two key dimensions:regional economy and ecological environment.Using panel data from 2013 to 2022,the coupling coordination degree model is employed to quantify the interactions and synergy between these dimensions.Additionally,spatial econometric methods are applied to calculate both global and local Moran’s Index,revealing spatial clustering patterns,regional disparities,and heterogeneity.The relative development model further identifies critical factors influencing regional coordination,with a focus on the lagging development of basic infrastructure and public services.The findings demonstrate a positive temporal trend toward improved regional coordination and reduced development gaps,with a spatial pattern characterized by higher coupling degrees in eastern and central regions compared to western areas.Based on these results,this study proposes actionable strategies to enhance coordinated development,emphasizing ecological conservation,the establishment of green production and consumption systems,ecological restoration,and strengthened municipal collaboration.This revised abstract emphasizes the study’s purpose,methods,and key findings more clearly while maintaining a professional and concise tone.Finally,based on the above analysis results,the corresponding coordinated development suggestions of regional economy and ecological environment are given from the aspects of ecological environment protection measures,green production and consumption system construction,ecological environment restoration and municipal coordination.
基金supported by Sichuan Science and Technology Program(Grant No.2020YFH0080)the National Natural Science Foundation of China(Grant No.51475386)the National Basic Research Project of China(973 Program,Grant No.2015CB654801).
文摘The gear transmission system directly affects the operational performance of high-speed trains(HST).However,current research on gear transmission systems of HST often overlooks the effects of gear eccentricity and running resistance,and the dynamic models of gear transmission system are not sufficiently comprehensive.This paper aims to establish an electromechanical coupling dynamic model of HST traction transmission system and study its electromechanical coupling vibration characteristics,in which the internal excitation factors such as gear eccentricity,time-varying meshing stiffness,backlash,meshing error,and external excitation factors such as electromagnetic torque and running resistance are stressed.The research results indicate that gear eccentricity and running resistance have a significant impact on the stability of the system,and gear eccentricity leads to intensified system vibration and decreased anti-interference ability.In addition,the characteristic frequency of gear eccentricity can be extracted from mechanical signals and current signals as a preliminary basis for eccentricity detection,and electrical signals can also be used to monitor changes in train running resistance in real time.The results of this study provide some useful insights into designing dynamic performance parameters for HST transmission systems and monitoring train operational states.
基金supported by 2024 Central Guidance Local Science and Technology Development Fund Project"Study on the mechanism and evaluation method of thermal pollution in water bodies,as well as research on thermal carrying capacity".(Grant 246Z4506G)Key Research and Development Project in Hebei Province:"Key Technologies and Equipment Research and Demonstration of Multiple Energy Complementary(Electricity,Heat,Cold System)for Solar Energy,Geothermal Energy,Phase Change Energy"(Grant 236Z4310G)the Hebei Academy of Sciences Key Research and Development Program"Research on Heat Transfer Mechanisms and Efficient Applications of Intermediate and Deep Geothermal Energy"(22702)。
文摘Ground source heat pump systems demonstrate significant potential for northern rural heating applications;however,the effectiveness of these systems is often limited by challenging geological conditions.For instance,in certain regions,the installation of buried pipes for heat exchangers may be complicated,and these pipes may not always serve as efficient low-temperature heat sources for the heat pumps of the system.To address this issue,the current study explored the use of solar-energy-collecting equipment to supplement buried pipes.In this design,both solar energy and geothermal energy provide low-temperature heat to the heat pump.First,a simulation model of a solar‒ground source heat pump coupling system was established using TRNSYS.The accuracy of this model was validated through experiments and simulations on various system configurations,including varying numbers of buried pipes,different areas of solar collectors,and varying volumes of water tanks.The simulations examined the coupling characteristics of these components and their influence on system performance.The results revealed that the operating parameters of the system remained consistent across the following configurations:three buried pipes,burial depth of 20 m,collector area of 6 m^(2),and water tank volume of 0.5 m^(3);four buried pipes,burial depth of 20 m,collector area of 3 m^(2),and water tank volume of 0.5 m^(3);and five buried pipes with a burial depth of 20 m.Furthermore,the heat collection capacity of the solar collectors spanning an area of 3 m^(2)was found to be equivalent to that of one buried pipe.Moreover,the findings revealed that the solar‒ground source heat pump coupling system demonstrated a lower annual cumulative energy consumption compared to the ground source heat pump system,presenting a reduction of 5.31%compared to the energy consumption of the latter.
基金supported by the National Natural Science Foundation of China(Grants No.W2412144,42271292)the 111 project,and the Fundamental Research Funds for the Central Universities of China.
文摘Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an urgent need for innovative research frameworks.Integrated geography synthesizes physical geography,human geography,and geographic information science,providing key frameworks for understanding complex human-environment systems.This editorial proposes an emerging research framework for integrated geography—“Composite driving-System evolution-Coupling mechanism-Synergistic regulation(CSCS)”—based on key issues such as climate change,biodiversity loss,resource scarcity,and social-ecological interactions,which have been highlighted in both recent critical literature on human-environment systems and UN assessment reports.The framework starts with diverse composite driving forces,extends to the evolution of human-environment system structures,processes,and functions that these drivers induce,explores couplings within human-environment systems,and calls for regulation aimed at sustainable development in synergies.Major research frontiers include understanding the cascading“evolution-coupling”effects of shocks;measuring system resilience,thresholds,and safe and just operating space boundaries;clarifying linkage mechanisms across scales;and achieving synergistic outcomes for multi-objective sustainability.This framework will help promote the interdisciplinary integration and development of integrated geography,and provide geographical solutions for the global sustainable development agenda.
基金funded by State Grid Beijing Electric Power Company Technology Project,grant number 520210230004.
文摘The park-level integrated energy system(PIES)is essential for achieving carbon neutrality by managing multi-energy supply and demand while enhancing renewable energy integration.However,current carbon trading mechanisms lack sufficient incentives for emission reductions,and traditional optimization algorithms often face challenges with convergence and local optima in complex PIES scheduling.To address these issues,this paper introduces a low-carbon dispatch strategy that combines a reward-penalty tiered carbon trading model with P2G-CCS integration,hydrogen utilization,and the Secretary Bird Optimization Algorithm(SBOA).Key innovations include:(1)A dynamic reward-penalty carbon trading mechanism with coefficients(μ=0.2,λ=0.15),which reduces carbon trading costs by 47.2%(from$694.06 to$366.32)compared to traditional tiered models,incentivizing voluntary emission reductions.(2)The integration of P2G-CCS coupling,which lowers natural gas consumption by 41.9%(from$4117.20 to$2389.23)and enhances CO_(2) recycling efficiency,addressing the limitations of standalone P2G or CCS technologies.(3)TheSBOA algorithm,which outperforms traditionalmethods(e.g.,PSO,GWO)in convergence speed and global search capability,avoiding local optima and achieving 24.39%faster convergence on CEC2005 benchmark functions.(4)A four-energy PIES framework incorporating electricity,heat,gas,and hydrogen,where hydrogen fuel cells and CHP systems improve demand response flexibility,reducing gas-related emissions by 42.1%and generating$13.14 in demand response revenue.Case studies across five scenarios demonstrate the strategy’s effectiveness:total operational costs decrease by 14.7%(from$7354.64 to$6272.59),carbon emissions drop by 49.9%(from 5294.94 to 2653.39kg),andrenewable energyutilizationincreases by24.39%(from4.82%to8.17%).These results affirmthemodel’s ability to reconcile economic and environmental goals,providing a scalable approach for low-carbon transitions in industrial parks.
基金supported by Young Talents from Longyuan,Gansu Province(Liwei Liu),the Fundamental Research Funds for the Central Universities,Northwest Minzu University(Grant No.31920230134)Teaching Achievement Cultivation Project of Gansu Province Department of Education(Grant No.2022GSJXCGPY-46)+1 种基金Special research topic on curriculum and teaching materials for primary,secondary and higher schools,Gansu Province Department of Education(Grant No.GSJC-Y2024204)Quality improvement project for undergraduate talent training,Northwest Minzu University(Grant Nos.2024YBJG-04 and 2024FCTD-03).
文摘This study theoretically investigates chaos in a cavity optomechanical system with Coulomb coupling.The system consists of a Fabry-Pérot cavity with a movable mirror,where Coulomb interactions arise from charging the two movable mirrors.We examine the chaotic dynamics under the influence of both single and bichromatic laser fields.The single laser field represents a system driven exclusively by the pump field,whereas the bichromatic field represents simultaneous driving by both the pump and probe fields.In addition to conventional chaos-inducing methods through parameter variations,we demonstrate that increasing the Coulomb coupling strength enhances the system’s nonlinearity and induces chaotic behavior.Furthermore,we propose several strategies for generating and controlling chaos,while also identifying the parameter ranges necessary for the resonance of the two mechanical oscillators.Interestingly,when adjusting the driving power in a system driven solely by the pump field,we unexpectedly observe the emergence of high-order sidebands.These findings contribute to the development of chaotic behavior in future cavity optomechanical systems and provide a theoretical basis for applications in physical random number generation and secure communication.
基金supported by the National Science Foundation of China(Grant No.12105026)Climbing Plan of Changchun University(Grant No.ZKP202010)Educational Commission of Jilin Province of China(Grant No.JJKH20230663KJ)。
文摘The circuit quantum electrodynamics(QED)system has brought us into an ultrastrong and deep coupling regime in the light-matter interaction community,in which the quantum effect has attracted significant interest.In this study,we theoretically investigated the photon blockade phenomenon in a double-transmon system operating in an ultrastrong coupling regime.We considered the effect of the counter-rotating wave terms in the interaction Hamiltonian and derived the master equation in the eigenpresentation.We found that photon blockade occurred in only one of the eigenmodes,and the counter-rotating wave terms enhanced the blockade by reducing the minimum value of the second-order correlation function.This study will be beneficial for the design of single-photon devices in circuit QED systems,especially in the ultrastrong coupling regime.
基金supported by the Natural Science Foundation of Sichuan Province,China(Youth Science Foundation)(Grant No.2022NSFSC1952).
文摘The collective dynamic of a fractional-order globally coupled system with time delays and fluctuating frequency is investigated.The power-law memory of the system is characterized using the Caputo fractional derivative operator.Additionally,time delays in the potential field force and coupling force transmission are both considered.Firstly,based on the delay decoupling formula,combined with statistical mean method and the fractional-order Shapiro–Loginov formula,the“statistic synchronization”among particles is obtained,revealing the statistical equivalence between the mean field behavior of the system and the behavior of individual particles.Due to the existence of the coupling delay,the impact of the coupling force on synchronization exhibits non-monotonic,which is different from the previous monotonic effects.Then,two kinds of theoretical expression of output amplitude gains G and G are derived by time-delay decoupling formula and small delay approximation theorem,respectively.Compared to G,G is an exact theoretical solution,which means that G is not only more accurate in the region of small delay,but also applies to the region of large delay.Finally,the study of the output amplitude gain G and its resonance behavior are explored.Due to the presence of the potential field delay,a new resonance phenomenon termed“periodic resonance”is discovered,which arises from the periodic matching between the potential field delay and the driving frequency.This resonance phenomenon is analyzed qualitatively and quantitatively,uncovering undiscovered characteristics in previous studies.
基金supported by the National Key R&D Program of China(2021YFF0501103).
文摘This article discusses the detailed examination of the engineering design and implementation process for direct Train-to-Train(T2T)communication within a wireless train backbone network in the context of a virtual coupling scenario.The article proposed several critical aspects,including the optimization of transmission data requirements,which is essential to ensure that communication between trains is efficient and reliable.The design of the T2T wireless communication subsystem is discussed in detail,outlining the technical specifications,protocols,and technologies employed to facilitate wireless communication between multiple trains.Additionally,the article presents a thorough analysis of the data collected during real-world train experiments,highlighting the performance metrics and challenges encountered during testing.This empirical data not only validates the effectiveness of the proposed design but also serves as a crucial reference for future advancements in T2T wireless communication systems.By combining both theoretical principles and practical outcomes,the article offers insights that will aid engineers and researchers in developing robust and efficient wireless communication systems for next-generation train operations.
基金supported by the National Natural Science Foundation of China[Grant NO.42361040]。
文摘Ecosystem service flows(ESFs)can reveal the interrelationships and impacts between natural systems and human activities.We can improve the stability and sustainability of ecosystems,more effectively utilize natural resources,protect the environment,and enhance the harmonious coexistence of humans and nature by comprehending ESFs.However,few studies have examined ESFs across scales and evaluated their sustainability;most have concentrated on regional scales.In order to quantify and analyze ESFs within the Jing River Basin(JRB)and between the JRB and the adjacent and distant regions from a water-food-energy perspective,this paper employs a meta-coupling framework.Additionally,it evaluates the sustainability of these flows using a techno-ecological synergy framework.The results show that the ESFs within the JRB was significant in 2020.Water production services were concentrated in the southern part of the JRB,while the distribution of food supply and carbon supply services was relatively even.Huan County emerged as the largest exporting county,providing 1.46×10^(8)kg of food to other counties and exporting 2.97×10^(6)kg of energy.The ESFs in the JRB primarily moved towards the neighboring and distant systems.Water production services flowed into the Guanzhong Plain Urban Agglomeration(GPUA),amounting to 5.8×10^(6)kg.Carbon supply services flowed out at 2.4×10^(5)kg,and food exports were the highest,reaching 5.0×10^(7)kg.The ecosystem service flows from the JRB to both the neighboring and distant systems enhanced food security and ecological resilience.The basin itself demonstrated good sustainability in food supply services,with an index value reaching 48.19.In crossscale calculations of food production sustainability with the adjacent GPUA,the index value increased from 48.19 to 52.99,indicating a significant improvement.These findings demonstrate that applying the meta-coupling framework provides an effective approach to quantify ESFs and assess their sustainability across scales.
基金supported by the National Natural Science Foundation of China(No.51974022).
文摘A hydrophobic composite coating was obtained on the carbon steel surface through electrochemical deposition of a copper coating in a sulfate solution and chemical vapor deposition of a carbon fiber film.It alleviated the serious corrosion problem of carbon steel on the evaporator of hot film coupled seawater desalination system in harsh marine environment.The morphologies and compositions of the coatings were analyzed,revealing the influence of electrodeposition time on their performance.The micro-nano copper structure formed by electrodeposition significantly improved the deposition effect of carbon layer.Additionally,experiments with seawater solution contact angle tests indicated that electrodeposition transformed the surface properties from hydrophilic to hydrophobic,effectively inhibiting the diffusion of corrosive medium into the interior of the substrate.Through polarization curves,electrochemical impedance spectroscopy,and other analyses,it was demonstrated that the hydrophobic coating significantly improves the corrosion resistance of carbon steel substrates in seawater environments,surpassing the performance of traditional duplex steel.
基金sponsored by National Natural Science Foundation of China(52077137).
文摘Under the“dual carbon”goals,this paper constructs an optimization model of the comprehensive energy system in the park.A stepwise carbon excess rate mechanism and an electric vehicle coupling strategy are proposed:A carbon quota trading system is established based on the baseline method,and the stepwise function is adopted to quantify the cost of excess carbon emissions;Introduce the price demand response and the two-way interaction mechanism of electric Vehicle vehicle-to-grid(V2G)to enhance the flexible regulation ability.Aiming at the uncertainty of wind and solar output,a typical scene set is generated by combining Latin hypercube sampling with the scene reduction method.The goal is to minimize the operating cost and maximize the consumption of renewable energy,and it is solved through the CPLEX solver in the MATLAB platform.Through simulation verification of the proposed models and methods in various scenarios,the simulation results show that under the coupling of the carbon excess rate trading mechanism,the demand response mechanism,and the vehicle-to-grid interaction of electric vehicles,the total daily operating cost of the system decreases by 25.3%,reduce the dual pressure of energy consumption costs and the economic environment,and achieve the coordinated optimization of economic and ecological benefits.
文摘Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental investigation is important in correlating the catalytic activity and the products.In this work,a spatial resolution online mass spectrometry(MS)system was developed and applied to a Mn-Na_(2)WO_(4)/SiO_(2) catalyzed OCM system.In addition to the residue gas analysis,the system obtained the distribution information of the reactants and products in the reactor.At various setting temperatures,all species online MS signals were collected at different positions,mapping the reaction activity covering parameters including temperature,time and space.The distribution behavior of the catalytic activity,selectivity,and apparent activation energy were kinetically analyzed.Selectivity and additional carbon balance analysis strongly supported the radical coupling model of OCM and indicated that after the catalytic bed layer,there is a significant length in the reactor(>2 mm)filled with radicals.Based on the result,a designed new method by tuning the temperature field in the reactor was found effectively to improve the catalytic activity,especially the C_(2) yield from 702 to 773℃.
基金supported by the Natural Science Foundation of China(Grant Nos.42088101 and 42375163)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030007)the specific research fund of The Innovation Platform for Academicians of Hainan Province(Grant No.YSPTZX202143)。
文摘In Earth system modeling,the land surface is coupled with the atmosphere through surface turbulent fluxes.These fluxes are computed using mean meteorological variables between the surface and a reference height in the atmosphere.However,the dependence of flux computation on the reference height,which is usually set as the lowest level in the atmosphere in Earth system models,has not received much attention.Based on high-resolution large-eddy simulation(LES)data under unstable conditions,we find the setting of reference height is not trivial within the framework of current surface layer theory.With a reasonable prescription of aerodynamic roughness length(following the setting in LESs),reference heights near the top of the surface layer tend to provide the best estimate of surface fluxes,especially for the momentum flux.Furthermore,this conclusion for the sensible heat flux is insensitive to the ratio of roughness length for momentum versus heat.These results are robust,whether using the classical or revised surface layer theory.They provide a potential guide for setting the proper reference heights for Earth system modeling and can be further tested in the near future using observational data from land–atmosphere feedback observatories.
基金supported by the Science and Technology Project of China Southern Power Grid Co.,Ltd under Grant 036000KC23090004(GDKJXM20231026).
文摘The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.
基金Supported by National Natural Science Foundation of China(Grant No.52475137)Sichuan Provincial Science and Technology Program(Grant No.2024YFHZ0280)Sichuan Provincial Nature and Science Foundation Innovation Research Group Project(Grant No.2023NSFSC1975).
文摘During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wheels,and the wheelsets will seriously affect the stability of the grinding force.In this paper,the coupled mechanical model of the grinding wheel/rail is established based on the contact mechanics theory,which is embedded as a submodel into the dynamic model of the multi-rigid buggy.The interaction among the frame,the grinding wheels and the wheelsets is analysed by setting the convex irregularity on the rail.The grinding effect is evaluated in combination with the subway’s long wave corrugation grinding conditions.The results show that when the grinding buggy passes the convex irregularity,the vibration excited by the wheelset system has a significant impact on the dynamic behavior of the grinding wheels.The vibration of the grinding wheel is mainly transmitted between the grinding wheel and the frame,less affecting the wheelset.For the long wave corrugation of the subway,the grinding effect of the grinding wheel has a certain correlation with the phase angle of the wheelset through the corrugation.The research results provide an important reference for the setting of the grinding pattern.
文摘A general scheme for generating a multi-component integrable equation hierarchy is proposed. A simple 3M- dimensional loop algebra ~X is produced. By taking advantage of ~X a new isospectral problem is established and then by making use of the Tu scheme the multi-component Dirac equation hierarchy is obtained. Finally, an expanding loop algebra ~FM of the loop algebra ~X is presented. Based on the ~FM, the multi-component integrable coupling system of the multi-component Dirac equation hierarchy is investigated. The method in this paper can be applied to other nonlinear evolution equation hierarchies.
基金supported by the National Natural Science Foundation of China(Nos.51927807,52074164,42277174,42077267 and 42177130)the Natural Science Foundation of Shandong Province,China(No.ZR2020JQ23)China University of Mining and Technology(Beijing)Top Innovative Talent Cultivation Fund for Doctoral Students(No.BBJ2023048)。
文摘In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses and strong disturbances and construction conditions such as the application of high prestress.It is essential to study the support components performance under dynamic-static coupling conditions.Based on this,a multi-functional anchorage support dynamic-static coupling performance test system(MAC system)is developed,which can achieve 7 types of testing functions,including single component performance,anchored net performance,anchored rock performance and so on.The bolt and cable mechanical tests are conducted by MAC system under different prestress levels.The results showed that compared to the non-prestress condition,the impact resistance performance of prestressed bolts(cables)is significantly reduced.In the prestress range of 50–160 k N,the maximum reduction rate of impact energy resisted by different types of bolts is 53.9%–61.5%compared to non-prestress condition.In the prestress range of 150–300 k N,the impact energy resisted by high-strength cable is reduced by76.8%–84.6%compared to non-prestress condition.The MAC system achieves dynamic-static coupling performance test,which provide an effective means for the design of anchorage support system.
基金Supported by the Research Work of Liaoning Provincial Development of Education under Grant No,2008670
文摘We propose a systematic method for generalizing the integrable couplings of soliton eqhations hierarchy with self-consistent sources associated with s/（4）. The JM equations hierarchy with self-consistent sources is derived. Furthermore, an integrable couplings of the JM soliton hierarchy with self-consistent sources is presented by using of the loop algebra sl（4）.
