In this study, we propose an algorithm selection method based on coupling strength for the partitioned analysis ofstructure-piezoelectric-circuit coupling, which includes two types of coupling or inverse and direct pi...In this study, we propose an algorithm selection method based on coupling strength for the partitioned analysis ofstructure-piezoelectric-circuit coupling, which includes two types of coupling or inverse and direct piezoelectriccoupling and direct piezoelectric and circuit coupling. In the proposed method, implicit and explicit formulationsare used for strong and weak coupling, respectively. Three feasible partitioned algorithms are generated, namely(1) a strongly coupled algorithm that uses a fully implicit formulation for both types of coupling, (2) a weaklycoupled algorithm that uses a fully explicit formulation for both types of coupling, and (3) a partially stronglycoupled and partially weakly coupled algorithm that uses an implicit formulation and an explicit formulation forthe two types of coupling, respectively.Numerical examples using a piezoelectric energy harvester,which is a typicalstructure-piezoelectric-circuit coupling problem, demonstrate that the proposed method selects the most costeffectivealgorithm.展开更多
To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study invest...To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.展开更多
Gypsum caprocks'sealing ability is affected by temperature-pressure coupling.Due to the limitations of experimental conditions,there is still a lack of triaxial stress-strain experiments that simultaneously consid...Gypsum caprocks'sealing ability is affected by temperature-pressure coupling.Due to the limitations of experimental conditions,there is still a lack of triaxial stress-strain experiments that simultaneously consider changes in temperature and pressure conditions,which limits the accuracy of the comprehensive evaluation of the brittle plastic evolution and sealing ability of gypsum rocks using temperature pressure coupling.Triaxial stress-strain tests were utilized to investigate the differences in the evolution of the confinement capacity of gypsum rocks under coupled temperaturepressure action and isothermal-variable pressure action on the basis of sample feasibility analysis.According to research,the gypsum rock's peak and residual strengths decrease under simultaneous increases in temperature and pressure over isothermal pressurization experimental conditions,and it becomes more ductile.This reduces the amount of time it takes for the rock to transition from brittle to plastic.When temperature is taken into account,both the brittle–plastic transformation's depth limit and the lithological transformation of gypsum rocks become shallower,and the evolution of gypsum rocks under variable temperature and pressure conditions is more complicated than that under isothermal pressurization.The sealing ability under the temperature-pressure coupling is more in line with the actual geological context when the application results of the Well#ZS5 are compared.This provides a theoretical basis for precisely determining the process of hydrocarbon accumulation and explains why the early hydrocarbon were not well preserved.展开更多
In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible plat...In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was performed.Relevant hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow theory.The results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling effect.According to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was considered.Furthermore,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were analyzed.Motion analysis revealed good agreement among the surge,sway,and yaw motions of the two floating bodies.However,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also observed.Therefore,excessive constraints should be added between the two floating bodies during construction to ensure construction safety.The numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 m.During construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.展开更多
To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing...To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be obtained.Firstly,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step schemes.Discussion on the wave elevation of uni-and bi-directional waves is also carried out.Then a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,respectively.Finally,the differences in structural response characteristics of trimaran in different wave fields are studied.The results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.展开更多
The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are investigated.The effects of the control and interface parameters on the system's stability are a...The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are investigated.The effects of the control and interface parameters on the system's stability are analyzed.The frequency range of self-excited vibrations is investigated from the energy point of view.The phenomenon of self-excited vibrations is elaborated with the phase trajectory.The corresponding control strategies are briefly analyzed with respect to the vibration mechanism.The results show that when the levitation objects collide with the mechanical interface,the system's vibration frequency becomes larger with the decrease in the collision gap;when the vibration frequency exceeds the critical frequency,the electromagnetic system continues to provide energy to the system,and the collision interface continuously dissipates energy so that the system enters the self-excited vibration state.展开更多
The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in ele...The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to date.Herein,we successfully realize the structural transformation of Pd Cu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing treatment.Specifically,the BCC Pd Cu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%,Faradaic efficiency of 88.60%,yield rate of 316.0 mmol h^(-1)g^(-1)_(Pd+Cu)and long-term stability for consecutive electrolysis within 20 h at-0.55 V vs.reversible hydrogen electrode,outperforming than those of FCC Pd Cu MAs.Under the membrane electrode assembly system,BCC Pd Cu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h^(-1)g^(-1)_(Pd+Cu).Density functional theory calculation reveals that the d-d orbital coupling in BCC Pd Cu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR performance.Our work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.展开更多
Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic h...Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.展开更多
Understanding the photoexcitation induced spin dynamics in ferromagnetic metals is important for the design of photo-controlled ultrafast spintronic device.In this work,by the ab initio nonadiabatic molecular dynamics...Understanding the photoexcitation induced spin dynamics in ferromagnetic metals is important for the design of photo-controlled ultrafast spintronic device.In this work,by the ab initio nonadiabatic molecular dynamics simulation,we have studied the spin dynamics induced by spin–orbit coupling(SOC)in Co and Fe using both spin-diabatic and spin-adiabatic representations.In Co system,it is found that the Fermi surface(E_(F))is predominantly contributed by the spin-minority states.The SOC induced spin flip will occur for the photo-excited spin-majority electrons as they relax to the E_(F),and the spin-minority electrons tend to relax to the EFwith the same spin through the electron–phonon coupling(EPC).The reduction of spin-majority electrons and the increase of spin-minority electrons lead to demagnetization of Co within100 fs.By contrast,in Fe system,the E_(F) is dominated by the spin-majority states.In this case,the SOC induced spin flip occurs for the photo-excited spin-minority electrons,which leads to a magnetization enhancement.If we move the E_(F) of Fe to higher energy by 0.6eV,the E_(F) will be contributed by the spin-minority states and the demagnetization will be observed again.This work provides a new perspective for understanding the SOC induced spin dynamics mechanism in magnetic metal systems.展开更多
Polymer-based composite electrolytes composed of three-dimensional Li_(6.4)La_(3)Zr_(2)Al_(0.2)O_(12)(3D-LLZAO)have attracted increasing attention due to their continuous ion conduction and satisfactory mechanical pro...Polymer-based composite electrolytes composed of three-dimensional Li_(6.4)La_(3)Zr_(2)Al_(0.2)O_(12)(3D-LLZAO)have attracted increasing attention due to their continuous ion conduction and satisfactory mechanical properties.However,the organic/inorganic interface is incompatible,resulting in slow lithium-ion transport at the interface.Therefore,the compatibility of organic/inorganic interface is an urgent problem to be solved.Inspired by the concept of“gecko eaves”,polymer-based composite solid electrolytes with dense interface structures were designed.The bridging of organic/inorganic interfaces was established by introducing silane coupling agent(3-chloropropyl)trimethoxysilane(CTMS)into the PEO-3D-LLZAO(PL)electrolyte.The in-situ coupling reaction improves the interface affinity,strengthens the organic/inorganic interaction,reduces the interface resistance,and thus achieves an efficient interface ion transport network.The prepared PEO-3D-LLZAO-CTMS(PLC)electrolyte exhibits enhanced ionic conductivity of 6.04×10^(-4)S cm^(-1)and high ion migration number(0.61)at 60℃and broadens the electrochemical window(5.1 V).At the same time,the PLC electrolyte has good thermal stability and high mechanical properties.Moreover,the Li Fe PO_(4)|PLC|Li battery has excellent rate performance and cycling stability with a capacity decay rate of 2.2%after 100 cycles at 60℃and 0.1 C.These advantages of PLC membranes indicate that this design approach is indeed practical,and the in-situ coupling method provides a new approach to address interface compatibility issues.展开更多
We investigate the nature of the strong coupling constant and related physics.Through the analysis of accumulated experimental data around the world,we employ the ability of machine learning to unravel its physical la...We investigate the nature of the strong coupling constant and related physics.Through the analysis of accumulated experimental data around the world,we employ the ability of machine learning to unravel its physical laws.The result of our efforts is a formula that captures the expansive panorama of the distribution of the strong coupling constant across the entire energy range.展开更多
A coupled numerical calculation method combining smooth particle hydrodynamics(SPH)and the finite element method(FEM)was implemented to investigate the seismic response of horizontal storage tanks.Anumericalmodel of a...A coupled numerical calculation method combining smooth particle hydrodynamics(SPH)and the finite element method(FEM)was implemented to investigate the seismic response of horizontal storage tanks.Anumericalmodel of a horizontal storage tank featuring a free liquid surface under seismic action was constructed using the SPH–FEM coupling method.The stored liquid was discretized using SPH particles,while the tank and supports were discretized using the FEM.The interaction between the stored liquid and the tank was simulated by using the meshless particle contact method.Then,the numerical simulation results were compared and analyzed against seismic simulation shaking table test data to validate the method.Subsequently,a series of numerical models,considering different liquid storage volumes and seismic effects,were constructed to obtain time history data of base shear and top center displacement,which revealed the seismic performance of horizontal storage tanks.Numerical simulation results and experimental data showed good agreement,with an error rate of less than 18.85%.And this conformity signifies the rationality of the SPH-FEM coupling method.The base shear and top center displacement values obtained by the coupled SPH-FEM method were only 53.3% to 69.1% of those calculated by the equivalent mass method employed in the current code.As the stored liquid volume increased,the seismic response of the horizontal storage tank exhibited a gradual upward trend,with the seismic response increasing from 73% to 388% for every 35% increase in stored liquid volume.The maximum von Mises stress of the tank and the supports remained below the steel yield strength during the earthquake.The coupled SPH-FEM method holds certain advantages in studying the seismic problems of tanks with complex structural forms,particularly due to the representation of the flow field distribution during earthquakes by involving reservoir fluid participation.展开更多
Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its co...Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its construction environment is more complex than that of a traditional reservoir.In particular,the stability of the rock strata in the underground reservoirs is affected by the seepage pressure and rock stress,which presents some challenges in achieving engineering safety and stability.Using the advantages of the numerical simulation method in dealing deal with nonlinear problems in engineering stability,in this study,the stability of the underground reservoir of the Shidangshan(SDS)pumped storage power station was numerically calculated and quantitatively analyzed based on fluid-structure coupling theory,providing an important reference for the safe operation and management of the underground reservoir.First,using the COMSOL software,a suitablemechanicalmodel was created in accordance with the geological structure and project characteristics of the underground reservoir.Next,the characteristics of the stress field,displacement field,and seepage field after excavation of the underground reservoir were simulated in light of the seepage effect of groundwater on the nearby rock of the underground reservoir.Finally,based on the construction specifications and Molar-Coulomb criterion,a thorough evaluation of the stability of the underground reservoir was performed through simulation of the filling and discharge conditions and anti-seepage strengthening measures.The findings demonstrate that the numerical simulation results have a certain level of reliability and are in accordance with the stress measured in the project area.The underground reservoir excavation resulted in a maximum displacement value of the rock mass around the caverns of 3.56 mm in a typical section,and the safety coefficient of the parts,as determined using the Molar-Coulomb criterion,was higher than 1,indicating that the project as a whole is in a stable state.展开更多
Coordinative development across various systems,particularly the economic,social,cultural,and human resources subsystems,is a key aspect of urban sustainability and has a direct impact on the quality of urbanization.T...Coordinative development across various systems,particularly the economic,social,cultural,and human resources subsystems,is a key aspect of urban sustainability and has a direct impact on the quality of urbanization.The Hangzhou Metropolitan Circle,comprising Hangzhou City,Huzhou City,Jiaxing City,and Shaoxing City,was the first metropolitan circle approved by the National Development and Reform Commission(NDRC)as a demonstration of economic transformation in China.To evaluate the coupling coordination degree of the four cities and analyze the coordinative development in three systems(including digital economy,regional innovation,and talent employment),we collected panel data during 2015–2022 from these four cities.The development level of the three systems was evaluated by the standard deviation method and comprehensive development index.The results are as follows:(1)the level of coupling coordinated development of the three systems in the Hangzhou Metropolitan Circle was relatively low;(2)the coupling coordination degree of the four cities in the Hangzhou Metropolitan Circle showed significant regional differences,among which Hangzhou City was in the leading position,and Huzhou,Jiaxing,and Shaoxing cities made steady but slow progress in the coupling development of the three systems;and(3)the development of digital economy and talent employment needs to be strengthened.This study contributes to the coordinative development of Hangzhou Metropolitan Circle by innovatively focusing on the coupling coordination relationship among digital economy,regional innovation,and talent employment,which also meets the industrial layout of Hangzhou Metropolitan Circle.In this way,the optimal allocation and sustainable development of digital economy,regional innovation,and talent employment in the Hangzhou Metropolitan Circle can be achieved.展开更多
Taking the pilgrimage,tourism and cultural island of Meizhou Island as an example,the evaluation index system of the coupling and coordinated development of“Mazu culture,socio-economy,eco-environment”(MSE)compound s...Taking the pilgrimage,tourism and cultural island of Meizhou Island as an example,the evaluation index system of the coupling and coordinated development of“Mazu culture,socio-economy,eco-environment”(MSE)compound system was constructed.The index weights were determined by AHP-entropy method,and the coupling degree,coordinated degree,comprehensive evaluation index and grey correlation degree of MSE system of Mazu Island from 2012 to 2022 were measure.The results showed that:(1)the comprehensive evaluation indexes of the three subsystems was on the rise in general,but the evaluation index of the ecological subsystems increased relatively slowly.(2)The coupling degree was only in the running-in stage in 2012,and the other years were in the coordinated coupling stage.(3)The coupling coordination degree increased from 0.35 in 2012 to 0.82 in 2022,the coupling coordination level was changed from mild imbalance to good coordination.(4)Through the comparison of grey correlation degree,the 24 indexes in the evaluation index system had great influence on the coupling coordination degree of MSE system.The coupling coordination degree was closely related to the development of socio-economy and the spread of Mazu culture.With the rapid development of tourism brought about by the spread of Mazu culture,the pressure on the ecological environment will be increasing.Compared with the rapid growth of tourism and economy,it is equally important to strengthen environmental protection and pay attention to the quality of ecological environment development.展开更多
Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern Ch...Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.展开更多
Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the ...Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the antenna number.However,recent studies suggest that the DOF could be less than the antenna number when strong mutual coupling is considered.We utilize a mutual-coupling-compliant channel model to investigate the DOF of the holographic MIMO(HMIMO)channel and give a upper bound of the DOF with strong mutual coupling.Our numerical simulations demonstrate that a dense array can support more DOF per unit aperture as compared with a half-wavelength MIMO system.展开更多
China-EU Summit charts the course for the development of China-EU relations with its first onsite session since 2019.D ESPITE the din about de-risking and decoupling made by some Western media,the convening of the 24t...China-EU Summit charts the course for the development of China-EU relations with its first onsite session since 2019.D ESPITE the din about de-risking and decoupling made by some Western media,the convening of the 24th EU-China Summit in Beijing on December 7,the first in-person one since 2019,showed the significant importance the two sides attached to the bilateral relations,and their mutual intention to steer the important ties toward more fruitful cooperation.展开更多
This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and stron...This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and strong coupling models for a thin cantilevered piezoelectric bimorph actuator.It is found that there is a significant difference between the strong and weak coupling solutions given by coupling direct and inverse piezoelectric effects(i.e.,piezoelectric coupling effect).In addition,there is significant longitudinal bending caused by the constraint of the inverse piezoelectric effect in the width direction at the fixed end(i.e.,3-D effect).Hence,modeling of these effects or 3-D piezoelectric coupling modeling is an electromechanical basis for the piezoelectric devices,which contributes to the accurate prediction of their behavior.展开更多
The chimera states underlying many realistic dynamical processes have attracted ample attention in the area of dynamical systems.Here, we generalize the Kuramoto model with nonlocal coupling incorporating higher-order...The chimera states underlying many realistic dynamical processes have attracted ample attention in the area of dynamical systems.Here, we generalize the Kuramoto model with nonlocal coupling incorporating higher-order interactions encoded with simplicial complexes.Previous works have shown that higher-order interactions promote coherent states.However, we uncover the fact that the introduced higher-order couplings can significantly enhance the emergence of the incoherent state.Remarkably, we identify that the chimera states arise as a result of multi-attractors in dynamic states.Importantly, we review that the increasing higher-order interactions can significantly shape the emergent probability of chimera states.All the observed results can be well described in terms of the dimension reduction method.This study is a step forward in highlighting the importance of nonlocal higher-order couplings, which might provide control strategies for the occurrence of spatial-temporal patterns in networked systems.展开更多
基金the Japan Society for the Promotion of Science,KAKENHI Grant Nos.20H04199 and 23H00475.
文摘In this study, we propose an algorithm selection method based on coupling strength for the partitioned analysis ofstructure-piezoelectric-circuit coupling, which includes two types of coupling or inverse and direct piezoelectriccoupling and direct piezoelectric and circuit coupling. In the proposed method, implicit and explicit formulationsare used for strong and weak coupling, respectively. Three feasible partitioned algorithms are generated, namely(1) a strongly coupled algorithm that uses a fully implicit formulation for both types of coupling, (2) a weaklycoupled algorithm that uses a fully explicit formulation for both types of coupling, and (3) a partially stronglycoupled and partially weakly coupled algorithm that uses an implicit formulation and an explicit formulation forthe two types of coupling, respectively.Numerical examples using a piezoelectric energy harvester,which is a typicalstructure-piezoelectric-circuit coupling problem, demonstrate that the proposed method selects the most costeffectivealgorithm.
基金jointly supported by the National Key Research and Development Program of China (2019YFC1905800)the National Key Research & Development Program of China (2018YFC1903500)+4 种基金the commercial project by Beijing Zhong Dian Hua Yuan Environment Protection Technology Co., Ltd. (E01211200005)the Regional key projects of the science and technology service network program (STS program) of the Chinese Academy of Sciences (KFJ-STS-QYZD-153)the Ningbo Science and Technology Innovation Key Projects (2020Z099, 2022Z028)the Ningbo Municipal Commonweal Key Program (2019C10033)the support of Mineral Resources Analytical and Testing Center, Institute of Process Engineering, Chinese Academy of Science
文摘To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.
基金funded by the National Natural Science Foundation of China(Grant No.42172147)PetroChina Major Science and Technology Project(Grant No.ZD2019-183-002).
文摘Gypsum caprocks'sealing ability is affected by temperature-pressure coupling.Due to the limitations of experimental conditions,there is still a lack of triaxial stress-strain experiments that simultaneously consider changes in temperature and pressure conditions,which limits the accuracy of the comprehensive evaluation of the brittle plastic evolution and sealing ability of gypsum rocks using temperature pressure coupling.Triaxial stress-strain tests were utilized to investigate the differences in the evolution of the confinement capacity of gypsum rocks under coupled temperaturepressure action and isothermal-variable pressure action on the basis of sample feasibility analysis.According to research,the gypsum rock's peak and residual strengths decrease under simultaneous increases in temperature and pressure over isothermal pressurization experimental conditions,and it becomes more ductile.This reduces the amount of time it takes for the rock to transition from brittle to plastic.When temperature is taken into account,both the brittle–plastic transformation's depth limit and the lithological transformation of gypsum rocks become shallower,and the evolution of gypsum rocks under variable temperature and pressure conditions is more complicated than that under isothermal pressurization.The sealing ability under the temperature-pressure coupling is more in line with the actual geological context when the application results of the Well#ZS5 are compared.This provides a theoretical basis for precisely determining the process of hydrocarbon accumulation and explains why the early hydrocarbon were not well preserved.
基金the National Natural Science Foundation of China(No.U20A20328).
文摘In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was performed.Relevant hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow theory.The results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling effect.According to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was considered.Furthermore,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were analyzed.Motion analysis revealed good agreement among the surge,sway,and yaw motions of the two floating bodies.However,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also observed.Therefore,excessive constraints should be added between the two floating bodies during construction to ensure construction safety.The numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 m.During construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.
基金financially supported by the State Key Laboratory of Structural Analysis,Optimization and CAE Software for Industrial Equipment,Dalian University of Technology(Grant No.GZ23112)the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2021ME146).
文摘To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be obtained.Firstly,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step schemes.Discussion on the wave elevation of uni-and bi-directional waves is also carried out.Then a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,respectively.Finally,the differences in structural response characteristics of trimaran in different wave fields are studied.The results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.
基金Project supported by the National Natural Science Foundation of China(No.12372005)。
文摘The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are investigated.The effects of the control and interface parameters on the system's stability are analyzed.The frequency range of self-excited vibrations is investigated from the energy point of view.The phenomenon of self-excited vibrations is elaborated with the phase trajectory.The corresponding control strategies are briefly analyzed with respect to the vibration mechanism.The results show that when the levitation objects collide with the mechanical interface,the system's vibration frequency becomes larger with the decrease in the collision gap;when the vibration frequency exceeds the critical frequency,the electromagnetic system continues to provide energy to the system,and the collision interface continuously dissipates energy so that the system enters the self-excited vibration state.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52161135302,22105087)the Postdoctoral Research Foundation of China(Grant No.2022M721360)the Natural Science Foundation of Jiangsu Province(Grant No.BK20210446)。
文摘The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to date.Herein,we successfully realize the structural transformation of Pd Cu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing treatment.Specifically,the BCC Pd Cu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%,Faradaic efficiency of 88.60%,yield rate of 316.0 mmol h^(-1)g^(-1)_(Pd+Cu)and long-term stability for consecutive electrolysis within 20 h at-0.55 V vs.reversible hydrogen electrode,outperforming than those of FCC Pd Cu MAs.Under the membrane electrode assembly system,BCC Pd Cu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h^(-1)g^(-1)_(Pd+Cu).Density functional theory calculation reveals that the d-d orbital coupling in BCC Pd Cu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR performance.Our work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.
基金the National Natural Science Foundation of China(22265021)the Aeronautical Science Foundation of China(2020Z056056003).
文摘Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.
基金support of Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0450101)the National Natural Science Foundation of China(Grant Nos.12125408 and 11974322)+1 种基金the Informatization Plan of Chinese Academy of Sciences(Grant No.CAS-WX2021SF-0105)the support of the National Natural Science Foundation of China(Grant No.12174363)。
文摘Understanding the photoexcitation induced spin dynamics in ferromagnetic metals is important for the design of photo-controlled ultrafast spintronic device.In this work,by the ab initio nonadiabatic molecular dynamics simulation,we have studied the spin dynamics induced by spin–orbit coupling(SOC)in Co and Fe using both spin-diabatic and spin-adiabatic representations.In Co system,it is found that the Fermi surface(E_(F))is predominantly contributed by the spin-minority states.The SOC induced spin flip will occur for the photo-excited spin-majority electrons as they relax to the E_(F),and the spin-minority electrons tend to relax to the EFwith the same spin through the electron–phonon coupling(EPC).The reduction of spin-majority electrons and the increase of spin-minority electrons lead to demagnetization of Co within100 fs.By contrast,in Fe system,the E_(F) is dominated by the spin-majority states.In this case,the SOC induced spin flip occurs for the photo-excited spin-minority electrons,which leads to a magnetization enhancement.If we move the E_(F) of Fe to higher energy by 0.6eV,the E_(F) will be contributed by the spin-minority states and the demagnetization will be observed again.This work provides a new perspective for understanding the SOC induced spin dynamics mechanism in magnetic metal systems.
基金supported by the Key Program(U20A20235)funded by the National Natural Science Foundation of Chinathe National Natural Science Foundation of China(52171127,51974242)+3 种基金the Natural Science Basic Research Program of Shaanxi(2023-JC-QN-0595)the Regional Innovation Capability Guidance Program of Shaanxi(2022QFY10-06)the Key R&D Program of Xianyang Science and Technology Bureau(2021ZDYF-GY-0029)the Program of Xi’an Science and Technology Bureau(23GXFW0066)。
文摘Polymer-based composite electrolytes composed of three-dimensional Li_(6.4)La_(3)Zr_(2)Al_(0.2)O_(12)(3D-LLZAO)have attracted increasing attention due to their continuous ion conduction and satisfactory mechanical properties.However,the organic/inorganic interface is incompatible,resulting in slow lithium-ion transport at the interface.Therefore,the compatibility of organic/inorganic interface is an urgent problem to be solved.Inspired by the concept of“gecko eaves”,polymer-based composite solid electrolytes with dense interface structures were designed.The bridging of organic/inorganic interfaces was established by introducing silane coupling agent(3-chloropropyl)trimethoxysilane(CTMS)into the PEO-3D-LLZAO(PL)electrolyte.The in-situ coupling reaction improves the interface affinity,strengthens the organic/inorganic interaction,reduces the interface resistance,and thus achieves an efficient interface ion transport network.The prepared PEO-3D-LLZAO-CTMS(PLC)electrolyte exhibits enhanced ionic conductivity of 6.04×10^(-4)S cm^(-1)and high ion migration number(0.61)at 60℃and broadens the electrochemical window(5.1 V).At the same time,the PLC electrolyte has good thermal stability and high mechanical properties.Moreover,the Li Fe PO_(4)|PLC|Li battery has excellent rate performance and cycling stability with a capacity decay rate of 2.2%after 100 cycles at 60℃and 0.1 C.These advantages of PLC membranes indicate that this design approach is indeed practical,and the in-situ coupling method provides a new approach to address interface compatibility issues.
基金supported by the National Natural Science Foundation of China(Grant Nos.12065014,12047501,12247101,and 12335001)the Natural Science Foundation of Gansu Province(Grant No.22JR5RA266)+5 种基金the West Light Foundation of Chinese Academy of Sciences(Grant No.21JR7RA201)supported by the China National Funds for Distinguished Young Scientists(Grant No.11825503)the National Key Research and Development Program of China(Grant No.2020YFA0406400)the 111 Project(Grant No.B20063)the fundamental Research Funds for the Central Universitiesthe Project for Top-Notch Innovative Talents of Gansu province。
文摘We investigate the nature of the strong coupling constant and related physics.Through the analysis of accumulated experimental data around the world,we employ the ability of machine learning to unravel its physical laws.The result of our efforts is a formula that captures the expansive panorama of the distribution of the strong coupling constant across the entire energy range.
基金supported by Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration(Grant Nos.2021B06,2021C05)Heilongjiang Natural Science Foundation Joint Guidance Project(Grant No.LH2021E122).
文摘A coupled numerical calculation method combining smooth particle hydrodynamics(SPH)and the finite element method(FEM)was implemented to investigate the seismic response of horizontal storage tanks.Anumericalmodel of a horizontal storage tank featuring a free liquid surface under seismic action was constructed using the SPH–FEM coupling method.The stored liquid was discretized using SPH particles,while the tank and supports were discretized using the FEM.The interaction between the stored liquid and the tank was simulated by using the meshless particle contact method.Then,the numerical simulation results were compared and analyzed against seismic simulation shaking table test data to validate the method.Subsequently,a series of numerical models,considering different liquid storage volumes and seismic effects,were constructed to obtain time history data of base shear and top center displacement,which revealed the seismic performance of horizontal storage tanks.Numerical simulation results and experimental data showed good agreement,with an error rate of less than 18.85%.And this conformity signifies the rationality of the SPH-FEM coupling method.The base shear and top center displacement values obtained by the coupled SPH-FEM method were only 53.3% to 69.1% of those calculated by the equivalent mass method employed in the current code.As the stored liquid volume increased,the seismic response of the horizontal storage tank exhibited a gradual upward trend,with the seismic response increasing from 73% to 388% for every 35% increase in stored liquid volume.The maximum von Mises stress of the tank and the supports remained below the steel yield strength during the earthquake.The coupled SPH-FEM method holds certain advantages in studying the seismic problems of tanks with complex structural forms,particularly due to the representation of the flow field distribution during earthquakes by involving reservoir fluid participation.
基金funded by the BeijingNatural Science Foundation of China(8222003)National Natural Science Foundation of China(41807180).
文摘Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its construction environment is more complex than that of a traditional reservoir.In particular,the stability of the rock strata in the underground reservoirs is affected by the seepage pressure and rock stress,which presents some challenges in achieving engineering safety and stability.Using the advantages of the numerical simulation method in dealing deal with nonlinear problems in engineering stability,in this study,the stability of the underground reservoir of the Shidangshan(SDS)pumped storage power station was numerically calculated and quantitatively analyzed based on fluid-structure coupling theory,providing an important reference for the safe operation and management of the underground reservoir.First,using the COMSOL software,a suitablemechanicalmodel was created in accordance with the geological structure and project characteristics of the underground reservoir.Next,the characteristics of the stress field,displacement field,and seepage field after excavation of the underground reservoir were simulated in light of the seepage effect of groundwater on the nearby rock of the underground reservoir.Finally,based on the construction specifications and Molar-Coulomb criterion,a thorough evaluation of the stability of the underground reservoir was performed through simulation of the filling and discharge conditions and anti-seepage strengthening measures.The findings demonstrate that the numerical simulation results have a certain level of reliability and are in accordance with the stress measured in the project area.The underground reservoir excavation resulted in a maximum displacement value of the rock mass around the caverns of 3.56 mm in a typical section,and the safety coefficient of the parts,as determined using the Molar-Coulomb criterion,was higher than 1,indicating that the project as a whole is in a stable state.
基金supported by the Ningbo Polytechnic Industry-Education Integration Research Project(NZ23CJ05Z)the Ningbo Municipal Philosophy and Social Science Project(G2023-2-Z11)the Soft Science Project of Zhejiang Science and Technology Department,China(2024C35096).
文摘Coordinative development across various systems,particularly the economic,social,cultural,and human resources subsystems,is a key aspect of urban sustainability and has a direct impact on the quality of urbanization.The Hangzhou Metropolitan Circle,comprising Hangzhou City,Huzhou City,Jiaxing City,and Shaoxing City,was the first metropolitan circle approved by the National Development and Reform Commission(NDRC)as a demonstration of economic transformation in China.To evaluate the coupling coordination degree of the four cities and analyze the coordinative development in three systems(including digital economy,regional innovation,and talent employment),we collected panel data during 2015–2022 from these four cities.The development level of the three systems was evaluated by the standard deviation method and comprehensive development index.The results are as follows:(1)the level of coupling coordinated development of the three systems in the Hangzhou Metropolitan Circle was relatively low;(2)the coupling coordination degree of the four cities in the Hangzhou Metropolitan Circle showed significant regional differences,among which Hangzhou City was in the leading position,and Huzhou,Jiaxing,and Shaoxing cities made steady but slow progress in the coupling development of the three systems;and(3)the development of digital economy and talent employment needs to be strengthened.This study contributes to the coordinative development of Hangzhou Metropolitan Circle by innovatively focusing on the coupling coordination relationship among digital economy,regional innovation,and talent employment,which also meets the industrial layout of Hangzhou Metropolitan Circle.In this way,the optimal allocation and sustainable development of digital economy,regional innovation,and talent employment in the Hangzhou Metropolitan Circle can be achieved.
基金This paper is supported by the National Natural Science Foundation of China(Grant No.31400318)the Fujian Provincial Department of Science and Technology Guided Projects(Grant No.2020Y0089)the STS Project of Fujian Science and Technology Department(Grant Nos.2021T3014,2022T3023).
文摘Taking the pilgrimage,tourism and cultural island of Meizhou Island as an example,the evaluation index system of the coupling and coordinated development of“Mazu culture,socio-economy,eco-environment”(MSE)compound system was constructed.The index weights were determined by AHP-entropy method,and the coupling degree,coordinated degree,comprehensive evaluation index and grey correlation degree of MSE system of Mazu Island from 2012 to 2022 were measure.The results showed that:(1)the comprehensive evaluation indexes of the three subsystems was on the rise in general,but the evaluation index of the ecological subsystems increased relatively slowly.(2)The coupling degree was only in the running-in stage in 2012,and the other years were in the coordinated coupling stage.(3)The coupling coordination degree increased from 0.35 in 2012 to 0.82 in 2022,the coupling coordination level was changed from mild imbalance to good coordination.(4)Through the comparison of grey correlation degree,the 24 indexes in the evaluation index system had great influence on the coupling coordination degree of MSE system.The coupling coordination degree was closely related to the development of socio-economy and the spread of Mazu culture.With the rapid development of tourism brought about by the spread of Mazu culture,the pressure on the ecological environment will be increasing.Compared with the rapid growth of tourism and economy,it is equally important to strengthen environmental protection and pay attention to the quality of ecological environment development.
基金This research is supported by Hunan Provincial Natural Science Foundation of China(Grant No.2021JJ30304)the General Topics of Hunan Social Science Achievement Evaluation Committee of China(Grant No.XSP22YBC366)the Key Scientific Research Project of Hunan Provincial Department of Education of China(Grant No.21B0592).
文摘Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.
基金supported in part by National Key Research and Develop⁃ment Program of China under Grant No.2020YFB1807600.
文摘Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the antenna number.However,recent studies suggest that the DOF could be less than the antenna number when strong mutual coupling is considered.We utilize a mutual-coupling-compliant channel model to investigate the DOF of the holographic MIMO(HMIMO)channel and give a upper bound of the DOF with strong mutual coupling.Our numerical simulations demonstrate that a dense array can support more DOF per unit aperture as compared with a half-wavelength MIMO system.
文摘China-EU Summit charts the course for the development of China-EU relations with its first onsite session since 2019.D ESPITE the din about de-risking and decoupling made by some Western media,the convening of the 24th EU-China Summit in Beijing on December 7,the first in-person one since 2019,showed the significant importance the two sides attached to the bilateral relations,and their mutual intention to steer the important ties toward more fruitful cooperation.
基金supported by the Japan Society for the Promotion of Science under KAKENHI Grant Nos.19F19379 and 20H04199。
文摘This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and strong coupling models for a thin cantilevered piezoelectric bimorph actuator.It is found that there is a significant difference between the strong and weak coupling solutions given by coupling direct and inverse piezoelectric effects(i.e.,piezoelectric coupling effect).In addition,there is significant longitudinal bending caused by the constraint of the inverse piezoelectric effect in the width direction at the fixed end(i.e.,3-D effect).Hence,modeling of these effects or 3-D piezoelectric coupling modeling is an electromechanical basis for the piezoelectric devices,which contributes to the accurate prediction of their behavior.
基金Project supported by the National Natural Science Foundation of China (Grants Nos.12375031 and 11905068)the Natural Science Foundation of Fujian Province, China (Grant No.2023J01113)the Scientific Research Funds of Huaqiao University (Grant No.ZQN-810)。
文摘The chimera states underlying many realistic dynamical processes have attracted ample attention in the area of dynamical systems.Here, we generalize the Kuramoto model with nonlocal coupling incorporating higher-order interactions encoded with simplicial complexes.Previous works have shown that higher-order interactions promote coherent states.However, we uncover the fact that the introduced higher-order couplings can significantly enhance the emergence of the incoherent state.Remarkably, we identify that the chimera states arise as a result of multi-attractors in dynamic states.Importantly, we review that the increasing higher-order interactions can significantly shape the emergent probability of chimera states.All the observed results can be well described in terms of the dimension reduction method.This study is a step forward in highlighting the importance of nonlocal higher-order couplings, which might provide control strategies for the occurrence of spatial-temporal patterns in networked systems.
