The coupling reactions of methanol and long-chain alkanes(n-dodecane,n-tetradecane and n-hexadecane)over CHA-type molecular sieves were studied in a fixed bed reactor.Over SAPO-34 and SSZ-13,it was found that the indu...The coupling reactions of methanol and long-chain alkanes(n-dodecane,n-tetradecane and n-hexadecane)over CHA-type molecular sieves were studied in a fixed bed reactor.Over SAPO-34 and SSZ-13,it was found that the induction period of methanol conversion was shortened by the introduction of long-chain alkanes.However,the addition of long-chain alkanes had little influence on the product distribution.Polymethylbenzenes and the derivatives were the main retained species on spent SSZ-13 catalyst,while adamantanes were the main retained species on SAPO-34.This indicates that coking species formation was mainly related to the further transformation of long-chain alkane/methanol coupling products at acid sites of the molecular sieve.These findings provide valuable information of long chain alkanes conversion and methanol reaction behavior of induction period over small pore CHA molecular sieves.展开更多
Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing addit...Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.展开更多
Transition metal-catalyzed C—C coupling reactions are a core strategy for the construction of carbon-carbon bonds in organic synthesis.Their development has not only promoted the synthesis of drugs,materials,and natu...Transition metal-catalyzed C—C coupling reactions are a core strategy for the construction of carbon-carbon bonds in organic synthesis.Their development has not only promoted the synthesis of drugs,materials,and natural products,but also promoted the development of new synthetic methods,and has also made breakthroughs in mechanism innovation and catalyst design.On this basis,a copper-catalyzed radical reaction between ketones is reported,enabling the synthesis of 2-carbonyl-1,4-diones.The method exhibits excellent applicability to multiple structural types of ketones,including aliphatic ketones with diverse substituents,aromatic ketones,and various simple ketones not limited to acetone,with wide applications,easy implementation,low catalyst toxicity,and low cost,cost-effective,and the product is easy to separate and purify.展开更多
Multilayer complex dynamical networks,characterized by the intricate topological connections and diverse hierarchical structures,present significant challenges in determining complete structural configurations due to ...Multilayer complex dynamical networks,characterized by the intricate topological connections and diverse hierarchical structures,present significant challenges in determining complete structural configurations due to the unique functional attributes and interaction patterns inherent to different layers.This paper addresses the critical question of whether structural information from a known layer can be used to reconstruct the unknown intralayer structure of a target layer within general weighted output-coupling multilayer networks.Building upon the generalized synchronization principle,we propose an innovative reconstruction method that incorporates two essential components in the design of structure observers,the cross-layer coupling modulator and the structural divergence term.A key advantage of the proposed reconstruction method lies in its flexibility to freely designate both the unknown target layer and the known reference layer from the general weighted output-coupling multilayer network.The reduced dependency on full-state observability enables more deployment in engineering applications with partial measurements.Numerical simulations are conducted to validate the effectiveness of the proposed structure reconstruction method.展开更多
This study aims to promote the optimization and upgrading of the economic structure in rural areas of China by focusing on the coupling coordination mechanism between digital economy–agriculture integration and rural...This study aims to promote the optimization and upgrading of the economic structure in rural areas of China by focusing on the coupling coordination mechanism between digital economy–agriculture integration and rural revitalization.By examining panel data from 30 Chinese provinces,autonomous regions,and municipalities between 2011 and 2022,the research constructs a weight-based evaluation system that integrates subjective and objective methods and a coupling coordination model to reveal its dynamic evolution patterns.Key findings indicate that digital economy–agriculture integration and rural revitalization achieve cross-coupling through critical activities.The impact of digital-agriculture integration on advancing rural revitalization lags by 2–3 years.Although the coupling development degree between the two systems continues to improve,it remains at the stage of primary coordination.Regional disparities are significant,showing a gradient pattern of“high degree of coupling development in the east and low degree of coupling development in the west.”展开更多
A series of new chiral amide ligands were prepared from natural amino acids and applied to the copper-catalyzed asymmetric oxidative homocoupling reaction of 3-hydroxy-2-naphthoates.By optimizing the reaction conditio...A series of new chiral amide ligands were prepared from natural amino acids and applied to the copper-catalyzed asymmetric oxidative homocoupling reaction of 3-hydroxy-2-naphthoates.By optimizing the reaction conditions,it was found that when using L3(5 mol%)as the ligand,CuCl(5 mol%)as the catalyst,dichloromethane as the solvent,2,2,6,6-tetramethylpiperidine 1-oxyl(TEMPO)/O2 as the oxidant,and under the reaction condition of 40℃,this method exhibited good substrate tolerance.Under these conditions,a series of chiral 1,1'-bi-2-naphthol(BINOL)derivatives were synthesized with yields of 45%~90%and enantioselectivities ranging from 50∶50 to 97∶3.展开更多
The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segmen...The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segment forming the ATP catalytic pocket is highly conserved.Single-molecule experiments,however,have revealed subtle differences in efficiency between the F_(1) and V_(1) motors.Here,we perform both atomistic and coarse-grained molecular dynamics simulations to investigate the mechanochemical coupling and coordination in F_(1) and V_(1) ATPase.Our results show that the correlation between conformational changes in F_(1) is stronger than that in V_(1),indicating that the mechanochemical coupling in F_(1) is tighter than in V_(1).Moreover,the unidirectional rotation of F_(1) is more processive than that of V_(1),which accounts for the higher efficiency observed in F_(1) and explains the occasional backward steps detected in single-molecule experiments on V_(1).展开更多
The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Rel...The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Relying solely on steady-state solutions cannot predict the detrimental effects caused by hysteresis.Consequently,this paper employs a quasi-steady-state fluid-thermalstructure multidisciplinary coupling solution method,integrating transient solid heat conduction with steady-state flow field and static structural deformation solutions.After conducting a numerical simulation of a three-dimensional,five-stage,low-pressure turbine air system,the following conclusions are drawn:when boundary conditions attain high-power states through processes that are numerically identical but in opposite directions,slight variations in solid deformation significantly impact the flow field;when boundary conditions attain high-power states through processes that are directionally consistent but have different numerical values,the influence of the boundary condition change rate on the flow field surpasses that of solid deformation.In terms of turbine design parameters,a large difference in stage-reaction between adjacent stages at the lower radius of the turbine can lead to significant changes in the disc cavity flow field during flight cycles.The difference in the stage-reaction of 0.23 at 10%blade height in adjacent stages may induce severe gas ingress in the stator disc cavity.Thus,it is crucial to minimize this difference and to appropriately extend the duration of the deceleration phase to ensure the turbine's safe operation.展开更多
Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling ...Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.展开更多
This study presents an implicit multiphysics coupling method integrating Computational Fluid Dynamics(CFD),the Multiphase Particle-in-Cell(MPPIC)model,and the Finite Element Method(FEM),implemented with OpenFOAM,Calcu...This study presents an implicit multiphysics coupling method integrating Computational Fluid Dynamics(CFD),the Multiphase Particle-in-Cell(MPPIC)model,and the Finite Element Method(FEM),implemented with OpenFOAM,CalculiX,and preCICE to simulate fluid-particle-structure interactions with large deformations.Mesh motion in the fluid field is handled using the radial basis function(RBF)method.The particle phase is modeled by MPPIC,where fluid-particle interaction is described through momentum exchange,and inter-particle collisions are characterized by collision stress.The structural field is solved by nonlinear FEM to capture large deformations induced by geometric nonlinearity.Coupling among fields is realized through a partitioned,parallel,and non-intrusive iterative strategy,ensuring stable transfer and convergence of interface forces and displacements.Notably,the influence of particles on the structure is not direct but mediated by the fluid,while structural motion directly affects particle dynamics.The results demonstrate that the proposed approach effectively captures multiphysics interaction processes and provides a valuable reference for numerical modeling of coupled fluid-particle-structure systems.展开更多
Global-and meso-scale dipolarizations are well-known features of Earth’s magnetosphere,but their coupling remains poorly understood.Here,using a new approach that combines two-dimentional(2D)ionospheric field-aligned...Global-and meso-scale dipolarizations are well-known features of Earth’s magnetosphere,but their coupling remains poorly understood.Here,using a new approach that combines two-dimentional(2D)ionospheric field-aligned current(FAC)maps with coordinated observations from a network of magnetospheric satellites,we directly show that individual global-scale dipolarizations can expand from the nightside to,or even into,the dayside.These expansions are enduring(20–30 minutes),slow(2–4 deg/min),and global in extent(up to 12 h in local time),consistent with previous statistical inferences but now explicitly observed.The expanding FACs form a two-sheet current system as described by the Boström II model.In contrast,meso-scale dipolarizations are bursty(a few minutes),fast(several tens deg/min),and localized(several hours in local time),as evidenced by auroral expansions and satellite data.They are associated with the line-current system as described by the Boström I model(i.e.,the substorm current wedge).Notably,meso-scale dipolarizations often emerge near the expanding edge of a global-scale dipolarization,suggesting a dynamic coupling between the two scales.These observations provide a complementary scenario to the simulation-based interpretation that global-scale dipolarizations result from the accumulation of meso-scale dipolarizations.Here,meso-scale dipolarizations appear far less frequently than in simulations and occur around the edge of global-scale dipolarizations.This result implies that meso-scale dipolarizations may be sporadically triggered during the azimuthal expansion of global-scale dipolarizations.展开更多
An efficient scheme is applied to generate a nonisospectral Botie-Pempinelli-Tu(BPT)integrable hierarchy under the case whereλ_(t)=n∑j=0 k_(j)(t)λ^(-j).Based on an expanding higherdimensional Lie algebra,we obtain ...An efficient scheme is applied to generate a nonisospectral Botie-Pempinelli-Tu(BPT)integrable hierarchy under the case whereλ_(t)=n∑j=0 k_(j)(t)λ^(-j).Based on an expanding higherdimensional Lie algebra,we obtain a nonisospectral BPT integrable coupling hieararchy.It follws that some new nonisospectral nonlinear systems are obtained by reducing these two nonisospectral BPT hierarchies.Actually,these nonisospectral integrable models that we obtained can enrich the existing integrable models and possibly describe new nonlinear phenomena.展开更多
The formation and development of natural fractures in tight sandstone reservoirs are governed by a combination of stratigraphic structure,lithological properties,and stress conditions.These fractures often exhibit irr...The formation and development of natural fractures in tight sandstone reservoirs are governed by a combination of stratigraphic structure,lithological properties,and stress conditions.These fractures often exhibit irregular geometries,signicant variations in height,and complex lling materials,leading to intricate conventional logging responses with pronounced multi-solution ambiguities that complicate accurate identication.To address this challenge,this study proposes a multi-model selective coupling identication method.This approach incorporated data cleaning,augmentation,and resampling techniques during the preprocessing phase.Subsequently,multi-dimensional feature extraction and cascade-based feature selection were performed,followed by optimizing model parameters using random search,Bayesian optimization,and grid search algorithms.High-performing models were selected via an evaluation framework.These models were then coupled through voting mechanisms to construct a robust identication model capable of deeply exploring the nonlinear relationship between fractures and logging data.The proposed method achieved an 85.19%fracture identication accuracy in blind tests involving 27 fracture segments across three wells,demonstrating strong identication capability.This methodology provides a valuable reference for fracture identication in hydrocarbon reservoirs within the Hongde area.展开更多
This study,taking Shaanxi Province as an example,systematically analyzed the coupling and coordination relationship between the digital economy and high-quality agricultural development from 2015 to 2024 by comprehens...This study,taking Shaanxi Province as an example,systematically analyzed the coupling and coordination relationship between the digital economy and high-quality agricultural development from 2015 to 2024 by comprehensively employing the coupling coordination model and the entropy method.The findings reveal that both the digital economy and high-quality agricultural development indices in Shaanxi Province exhibit a consistent upward trend.The level of coupling coordination has progressively transitioned from a low degree of coupling to a coordinated development stage,establishing a virtuous interactive pattern characterized by"digital enabling agriculture"and"agriculture driving innovation".The driving force behind this coupling primarily stems from the synergistic interplay of a triple mechanism involving"policy guidance,technological breakthroughs,and industrial support".However,structural imbalances persist across regions and agricultural segments,chiefly manifested as the digital divide between the Guanzhong Plain and the Northern(Shaanbei)and Southern(Shaannan)regions,alongside insufficient integration depth of digital technologies in the latter stages of the agricultural industry chain.To address these challenges,the study proposes recommendations including building a"tri-chain integrated"technological ecosystem,optimizing a differentiated policy support mechanism,and implementing regionally targeted strategies.These measures aim to foster deep integration of the digital economy with the entire agricultural value chain across diverse regions,offering pathways for western agricultural provinces to bridge the digital divide and achieve rural revitalization.展开更多
The strong electron-phonon coupling in organic photovoltaic materials significantly impedes exciton transport and promotes charge recombination,thereby exerting a detrimental effect on the overall performance of organ...The strong electron-phonon coupling in organic photovoltaic materials significantly impedes exciton transport and promotes charge recombination,thereby exerting a detrimental effect on the overall performance of organic solar cells(OSCs).Mitigating electron-phonon coupling is therefore essential for developing high-performance OSCs.In this work,we introduce two solid additives,1-bromo-3-chloronaphthalene(BCN-1)and 1-chloro-3-bromonaphthalene(BCN-2),into the bulk heterojunction active layer to address this fundamental challenge.We demonstrate that BCN-2 effectively suppresses high-frequency lattice vibrations,which minimizes electron-phonon scattering and thereby promotes efficient and long-range exciton diffusion.As a result,the BCN-2 processed devices exhibit prolonged exciton lifetime and superior charge carrier mobility compared to the control devices.These synergistic improvements in photophysical properties such as charge transport,contribute to a remarkable power conversion efficiency of 19.72%in the PM6:L8-BO-based OSCs.This work underscores the suppression of electron-phonon coupling as a critical and general strategy for advancing the performance of organic photovoltaic devices.展开更多
In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally r...In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally resonant effect,which contains two parts:the first part is induced by translation coupling,and the second part is induced by rotation coupling.The second part cannot be reflected by most existing theoretical models.The analytical solutions of the dynamic response are compared with the direct numerical simulation(DNS)results for two locally resonant plates with different resonator types,thereby validating the general applicability of the present model.The rotation coupling effect leads to the frequency-dependent effective rotational inertia density and anisotropic dispersion relation of the locally resonant plate,as well as the enhancement of the structural vibration suppression ability.展开更多
With the rapid advancement of electromagnetic launch technology,enhancing the structural stability and thermal resistance of armatures has become essential for improving the overall efficiency and reliability of railg...With the rapid advancement of electromagnetic launch technology,enhancing the structural stability and thermal resistance of armatures has become essential for improving the overall efficiency and reliability of railgun systems.Traditional aluminum alloy armatures often suffer from severe ablation,deformation,and uneven current distribution under high pulsed currents,which limit their performance and service life.To address these challenges,this study employs the Johnson–Cook constitutive model and the finite element method to develop armature models of aluminum matrix composites with varying heterogeneous graphene volume fractions.The temperature,stress,and strain of the armatures during operation were analyzed to investigate the effects of different graphene volume fractions on the deformation and damage behavior of aluminum matrix composite armatures under the multi-field coupling of electromagnetic,thermal,and structural interactions.The results indicate that,compared to the 6061 aluminum alloy matrix,the graphene-reinforced aluminum matrix composite armature significantly suppresses ablation damage at the tail and throat edges.The incorporation of graphene notably reduces the temperature rise during the armature emission process,increases the muzzle velocity under identical current excitation,and mitigates directional deformation of the armature.The 1 wt.% graphene-reinforced aluminum matrix composite armature demonstrates better agreement with experimental results at a strain rate of 2000 s^(-1),while simultaneously improving stress-strain response,reducing temperature rise,and improving velocity performance.展开更多
A comprehensive full-sieve-hole grading correction method was used to adjust aggregate gradings.The fatigue properties of recycled concrete aggregate(RCA)asphalt mixtures were investigated using an improved indirect t...A comprehensive full-sieve-hole grading correction method was used to adjust aggregate gradings.The fatigue properties of recycled concrete aggregate(RCA)asphalt mixtures were investigated using an improved indirect tensile fatigue test under temperature-humidity coupling based on 20-year meteorological data of Beijing,and the degeneration mechanism was further explored by scanning electron microscopy and energy-dispersive spectroscopy.The experimental results indicate that replacing 5-20 mm coarse limestone aggregate(LA)with RCA at a 50% substitution volume can mitigate the impact of RCA variations on the asphalt mixture proportioning design.All RCA asphalt mixtures have lower initial fatigue properties than the LA asphalt mixture.However,under temperature-humidity coupling,the long-term fatigue property of an RCA asphalt mixture with a low proportion of recycled brick exceeds that of the LA asphalt mixture,and the fatigue life decline rate of the RCA asphalt mixture during 10-year service decreases by approximately 25%.This is due to the penetration of the asphalt mortar into the RCA through the pores and cracks on the RCA surface.It forms an interfacial transition zone composed of asphalt mortar and cement mortar and further reduces the mixture damage caused by the water and freeze-thaw conditions.展开更多
Hydraulic asphalt concrete(HAC)has been increasingly employed as an appropriate impervious structure in hydraulic and hydropower engineering.However,asphalt mortar,usually seen as the matrix of HAC composite,is partic...Hydraulic asphalt concrete(HAC)has been increasingly employed as an appropriate impervious structure in hydraulic and hydropower engineering.However,asphalt mortar,usually seen as the matrix of HAC composite,is particularly prone to damage under combined stress and seepage interactions,and the mesoscale investigations on the damage-seepage coupling behavior of HAC under complex stress states remain limited.This research develops a numerical three-dimensional mesoscale model composed of asphalt mortar and polyhedral aggregate to investigate the stress-damage-seepage coupling behavior in HAC.In this model,asphalt mortar yields the viscoelastic continuum damage law and aggregate obeys the Mazars’elastic-brittle damage law;simultaneously,the effective permeability coefficient of asphalt mortar is assumed to follow an exponential function of damage.The predicted deviatoric stress-strain and hydraulic gradient-seepage curves both are in good agreement with the reported experimental results,which shows the proposed model is valid and reasonable.The simulated results indicate that the damaged asphalt mortar can induce localized areas of high permeability,which in turn affects the overall impervious performance of HAC.展开更多
基金Supported by National Natural Science Foundation of China(21991093)。
文摘The coupling reactions of methanol and long-chain alkanes(n-dodecane,n-tetradecane and n-hexadecane)over CHA-type molecular sieves were studied in a fixed bed reactor.Over SAPO-34 and SSZ-13,it was found that the induction period of methanol conversion was shortened by the introduction of long-chain alkanes.However,the addition of long-chain alkanes had little influence on the product distribution.Polymethylbenzenes and the derivatives were the main retained species on spent SSZ-13 catalyst,while adamantanes were the main retained species on SAPO-34.This indicates that coking species formation was mainly related to the further transformation of long-chain alkane/methanol coupling products at acid sites of the molecular sieve.These findings provide valuable information of long chain alkanes conversion and methanol reaction behavior of induction period over small pore CHA molecular sieves.
基金National Key Research and Development Program of China(2022YFB4600902)Shandong Provincial Science Foundation for Outstanding Young Scholars(ZR2024YQ020)。
文摘Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.
基金Project supported by the Basic Research Support Program for Outstanding Young Teachers in Provincial Undergraduate Colleges and Universities in Heilongjiang Province(No.YQJH2024096)the Heilongjiang Province Natural Joint Guidance Cultivation Project(No.PL2024H198)。
文摘Transition metal-catalyzed C—C coupling reactions are a core strategy for the construction of carbon-carbon bonds in organic synthesis.Their development has not only promoted the synthesis of drugs,materials,and natural products,but also promoted the development of new synthetic methods,and has also made breakthroughs in mechanism innovation and catalyst design.On this basis,a copper-catalyzed radical reaction between ketones is reported,enabling the synthesis of 2-carbonyl-1,4-diones.The method exhibits excellent applicability to multiple structural types of ketones,including aliphatic ketones with diverse substituents,aromatic ketones,and various simple ketones not limited to acetone,with wide applications,easy implementation,low catalyst toxicity,and low cost,cost-effective,and the product is easy to separate and purify.
基金Project supported by the National Natural Science Foun-dation of China(Grant No.62373197)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(Grant No.23KJB120010)+1 种基金the Industry-University-Research Cooperation Project of Jiangsu Province,China(Grant No.BY20251038)the Cultivation and In-cubation Project of the College of Automation,Nanjing Uni-versity of Posts and Telecommunications.
文摘Multilayer complex dynamical networks,characterized by the intricate topological connections and diverse hierarchical structures,present significant challenges in determining complete structural configurations due to the unique functional attributes and interaction patterns inherent to different layers.This paper addresses the critical question of whether structural information from a known layer can be used to reconstruct the unknown intralayer structure of a target layer within general weighted output-coupling multilayer networks.Building upon the generalized synchronization principle,we propose an innovative reconstruction method that incorporates two essential components in the design of structure observers,the cross-layer coupling modulator and the structural divergence term.A key advantage of the proposed reconstruction method lies in its flexibility to freely designate both the unknown target layer and the known reference layer from the general weighted output-coupling multilayer network.The reduced dependency on full-state observability enables more deployment in engineering applications with partial measurements.Numerical simulations are conducted to validate the effectiveness of the proposed structure reconstruction method.
基金Youth project under the National Social Science Foundation of China(15CJY054)key project in Philosophy and Social Sciences funded by the Chongqing Municipal Education Commission(22SKGH091)。
文摘This study aims to promote the optimization and upgrading of the economic structure in rural areas of China by focusing on the coupling coordination mechanism between digital economy–agriculture integration and rural revitalization.By examining panel data from 30 Chinese provinces,autonomous regions,and municipalities between 2011 and 2022,the research constructs a weight-based evaluation system that integrates subjective and objective methods and a coupling coordination model to reveal its dynamic evolution patterns.Key findings indicate that digital economy–agriculture integration and rural revitalization achieve cross-coupling through critical activities.The impact of digital-agriculture integration on advancing rural revitalization lags by 2–3 years.Although the coupling development degree between the two systems continues to improve,it remains at the stage of primary coordination.Regional disparities are significant,showing a gradient pattern of“high degree of coupling development in the east and low degree of coupling development in the west.”
文摘A series of new chiral amide ligands were prepared from natural amino acids and applied to the copper-catalyzed asymmetric oxidative homocoupling reaction of 3-hydroxy-2-naphthoates.By optimizing the reaction conditions,it was found that when using L3(5 mol%)as the ligand,CuCl(5 mol%)as the catalyst,dichloromethane as the solvent,2,2,6,6-tetramethylpiperidine 1-oxyl(TEMPO)/O2 as the oxidant,and under the reaction condition of 40℃,this method exhibited good substrate tolerance.Under these conditions,a series of chiral 1,1'-bi-2-naphthol(BINOL)derivatives were synthesized with yields of 45%~90%and enantioselectivities ranging from 50∶50 to 97∶3.
基金supported by the National Natural Science Foundation of China(Grant Nos.22193032 and 32401033)the Research Fund of Wenzhou Institute,Chinese Academy of Sciences(Grant Nos.WIUCASQD2020009,WIUCASQD2023005,XSZD2024004,2021HZSY0061,and WIUCASICTP2022)。
文摘The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segment forming the ATP catalytic pocket is highly conserved.Single-molecule experiments,however,have revealed subtle differences in efficiency between the F_(1) and V_(1) motors.Here,we perform both atomistic and coarse-grained molecular dynamics simulations to investigate the mechanochemical coupling and coordination in F_(1) and V_(1) ATPase.Our results show that the correlation between conformational changes in F_(1) is stronger than that in V_(1),indicating that the mechanochemical coupling in F_(1) is tighter than in V_(1).Moreover,the unidirectional rotation of F_(1) is more processive than that of V_(1),which accounts for the higher efficiency observed in F_(1) and explains the occasional backward steps detected in single-molecule experiments on V_(1).
基金supported by the National Science and Tech-nology Major Project,China(No.J2019-II-0012-0032)。
文摘The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Relying solely on steady-state solutions cannot predict the detrimental effects caused by hysteresis.Consequently,this paper employs a quasi-steady-state fluid-thermalstructure multidisciplinary coupling solution method,integrating transient solid heat conduction with steady-state flow field and static structural deformation solutions.After conducting a numerical simulation of a three-dimensional,five-stage,low-pressure turbine air system,the following conclusions are drawn:when boundary conditions attain high-power states through processes that are numerically identical but in opposite directions,slight variations in solid deformation significantly impact the flow field;when boundary conditions attain high-power states through processes that are directionally consistent but have different numerical values,the influence of the boundary condition change rate on the flow field surpasses that of solid deformation.In terms of turbine design parameters,a large difference in stage-reaction between adjacent stages at the lower radius of the turbine can lead to significant changes in the disc cavity flow field during flight cycles.The difference in the stage-reaction of 0.23 at 10%blade height in adjacent stages may induce severe gas ingress in the stator disc cavity.Thus,it is crucial to minimize this difference and to appropriately extend the duration of the deceleration phase to ensure the turbine's safe operation.
基金supported by the National Key Research and Development Program of China (MOST)(Grant No.2022YFA1402800)the Chinese Academy of Sciences (CAS) Presidents International Fellowship Initiative (PIFI)(Grant No.2025PG0006)+3 种基金the National Natural Science Foundation of China (NSFC)(Grant Nos.51831012,12274437,and 52161160334)the CAS Project for Young Scientists in Basic Research (Grant No.YSBR-084)the CAS Youth Interdisciplinary Teamthe China Postdoctoral Science Foundation (Grant No.2025M773402)。
文摘Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.
基金supported in part by the Mining Hydraulic Technology and Equipment Engineering Research Center,Liaoning Technical University,Fuxin,China(Grant No.MHTE23-R04)the Fundamental Research Funds for the Central Universities(ID N25BSS068).
文摘This study presents an implicit multiphysics coupling method integrating Computational Fluid Dynamics(CFD),the Multiphase Particle-in-Cell(MPPIC)model,and the Finite Element Method(FEM),implemented with OpenFOAM,CalculiX,and preCICE to simulate fluid-particle-structure interactions with large deformations.Mesh motion in the fluid field is handled using the radial basis function(RBF)method.The particle phase is modeled by MPPIC,where fluid-particle interaction is described through momentum exchange,and inter-particle collisions are characterized by collision stress.The structural field is solved by nonlinear FEM to capture large deformations induced by geometric nonlinearity.Coupling among fields is realized through a partitioned,parallel,and non-intrusive iterative strategy,ensuring stable transfer and convergence of interface forces and displacements.Notably,the influence of particles on the structure is not direct but mediated by the fluid,while structural motion directly affects particle dynamics.The results demonstrate that the proposed approach effectively captures multiphysics interaction processes and provides a valuable reference for numerical modeling of coupled fluid-particle-structure systems.
基金NASA(National Aeronautics and Space Administration)grant 81NSSC19K0306NASA prime contract NAS5-01072+6 种基金AFOSR(Air Force Office of Scientific Research)grant FA9559-16-1-0364NSF(National Science Foundation)grant AGS-2055192NASA grants 80NSSC20K1314,80NSSC20K1316,and 80NSSC21K1407NASA Contract NAS5-02099NASA grants:80NSSC18K1220 and 80NSSC18K0570NASA contracts 80GSFC17C0018,and NAS5-02099NASA award 80NSSC18K122。
文摘Global-and meso-scale dipolarizations are well-known features of Earth’s magnetosphere,but their coupling remains poorly understood.Here,using a new approach that combines two-dimentional(2D)ionospheric field-aligned current(FAC)maps with coordinated observations from a network of magnetospheric satellites,we directly show that individual global-scale dipolarizations can expand from the nightside to,or even into,the dayside.These expansions are enduring(20–30 minutes),slow(2–4 deg/min),and global in extent(up to 12 h in local time),consistent with previous statistical inferences but now explicitly observed.The expanding FACs form a two-sheet current system as described by the Boström II model.In contrast,meso-scale dipolarizations are bursty(a few minutes),fast(several tens deg/min),and localized(several hours in local time),as evidenced by auroral expansions and satellite data.They are associated with the line-current system as described by the Boström I model(i.e.,the substorm current wedge).Notably,meso-scale dipolarizations often emerge near the expanding edge of a global-scale dipolarization,suggesting a dynamic coupling between the two scales.These observations provide a complementary scenario to the simulation-based interpretation that global-scale dipolarizations result from the accumulation of meso-scale dipolarizations.Here,meso-scale dipolarizations appear far less frequently than in simulations and occur around the edge of global-scale dipolarizations.This result implies that meso-scale dipolarizations may be sporadically triggered during the azimuthal expansion of global-scale dipolarizations.
基金Supported by the National Natural Science Foundation of China(11971475)。
文摘An efficient scheme is applied to generate a nonisospectral Botie-Pempinelli-Tu(BPT)integrable hierarchy under the case whereλ_(t)=n∑j=0 k_(j)(t)λ^(-j).Based on an expanding higherdimensional Lie algebra,we obtain a nonisospectral BPT integrable coupling hieararchy.It follws that some new nonisospectral nonlinear systems are obtained by reducing these two nonisospectral BPT hierarchies.Actually,these nonisospectral integrable models that we obtained can enrich the existing integrable models and possibly describe new nonlinear phenomena.
基金supported by the"Tianchi Talents"Program of the Xinjiang Uygur Autonomous Region(Project No.51052300560)National Natural Science Foundation of China(Project No.42464006)the Open Fund Project of Key Laboratory of Oil and Gas Resources Research of the Gansu Province(Project No.SZDKFJJ2023007).
文摘The formation and development of natural fractures in tight sandstone reservoirs are governed by a combination of stratigraphic structure,lithological properties,and stress conditions.These fractures often exhibit irregular geometries,signicant variations in height,and complex lling materials,leading to intricate conventional logging responses with pronounced multi-solution ambiguities that complicate accurate identication.To address this challenge,this study proposes a multi-model selective coupling identication method.This approach incorporated data cleaning,augmentation,and resampling techniques during the preprocessing phase.Subsequently,multi-dimensional feature extraction and cascade-based feature selection were performed,followed by optimizing model parameters using random search,Bayesian optimization,and grid search algorithms.High-performing models were selected via an evaluation framework.These models were then coupled through voting mechanisms to construct a robust identication model capable of deeply exploring the nonlinear relationship between fractures and logging data.The proposed method achieved an 85.19%fracture identication accuracy in blind tests involving 27 fracture segments across three wells,demonstrating strong identication capability.This methodology provides a valuable reference for fracture identication in hydrocarbon reservoirs within the Hongde area.
文摘This study,taking Shaanxi Province as an example,systematically analyzed the coupling and coordination relationship between the digital economy and high-quality agricultural development from 2015 to 2024 by comprehensively employing the coupling coordination model and the entropy method.The findings reveal that both the digital economy and high-quality agricultural development indices in Shaanxi Province exhibit a consistent upward trend.The level of coupling coordination has progressively transitioned from a low degree of coupling to a coordinated development stage,establishing a virtuous interactive pattern characterized by"digital enabling agriculture"and"agriculture driving innovation".The driving force behind this coupling primarily stems from the synergistic interplay of a triple mechanism involving"policy guidance,technological breakthroughs,and industrial support".However,structural imbalances persist across regions and agricultural segments,chiefly manifested as the digital divide between the Guanzhong Plain and the Northern(Shaanbei)and Southern(Shaannan)regions,alongside insufficient integration depth of digital technologies in the latter stages of the agricultural industry chain.To address these challenges,the study proposes recommendations including building a"tri-chain integrated"technological ecosystem,optimizing a differentiated policy support mechanism,and implementing regionally targeted strategies.These measures aim to foster deep integration of the digital economy with the entire agricultural value chain across diverse regions,offering pathways for western agricultural provinces to bridge the digital divide and achieve rural revitalization.
基金supported by the NSFC(52522314,52473200,52450063,52120105006,51925306)the National Key R&D Program of China(2018FYA 0305800)+2 种基金the Key Research Program of Chinese Academy of Sciences(XDPB08-2)the Youth Innovation Promotion Asso-ciation of Chinese Academy of Sciences(2022165)the Fundamental Research Funds for the Central Universities(E3ET1803).
文摘The strong electron-phonon coupling in organic photovoltaic materials significantly impedes exciton transport and promotes charge recombination,thereby exerting a detrimental effect on the overall performance of organic solar cells(OSCs).Mitigating electron-phonon coupling is therefore essential for developing high-performance OSCs.In this work,we introduce two solid additives,1-bromo-3-chloronaphthalene(BCN-1)and 1-chloro-3-bromonaphthalene(BCN-2),into the bulk heterojunction active layer to address this fundamental challenge.We demonstrate that BCN-2 effectively suppresses high-frequency lattice vibrations,which minimizes electron-phonon scattering and thereby promotes efficient and long-range exciton diffusion.As a result,the BCN-2 processed devices exhibit prolonged exciton lifetime and superior charge carrier mobility compared to the control devices.These synergistic improvements in photophysical properties such as charge transport,contribute to a remarkable power conversion efficiency of 19.72%in the PM6:L8-BO-based OSCs.This work underscores the suppression of electron-phonon coupling as a critical and general strategy for advancing the performance of organic photovoltaic devices.
基金Project supported by the National Natural Science Foundation of China(No.12472062)。
文摘In this paper,a theoretical model is established for locally resonant plates with general resonators,and the corresponding governing equation is derived.The model provides a mathematical demonstration of the locally resonant effect,which contains two parts:the first part is induced by translation coupling,and the second part is induced by rotation coupling.The second part cannot be reflected by most existing theoretical models.The analytical solutions of the dynamic response are compared with the direct numerical simulation(DNS)results for two locally resonant plates with different resonator types,thereby validating the general applicability of the present model.The rotation coupling effect leads to the frequency-dependent effective rotational inertia density and anisotropic dispersion relation of the locally resonant plate,as well as the enhancement of the structural vibration suppression ability.
基金funded Basic Research Projects of Higher Education Institutions in Liaoning Province(JYTZD20230004)Future Industry Frontier Technology Project in Liaoning Province in 2025(2025JH2/101330141)Key Research and Development Program of Liaoning Province in 2025.
文摘With the rapid advancement of electromagnetic launch technology,enhancing the structural stability and thermal resistance of armatures has become essential for improving the overall efficiency and reliability of railgun systems.Traditional aluminum alloy armatures often suffer from severe ablation,deformation,and uneven current distribution under high pulsed currents,which limit their performance and service life.To address these challenges,this study employs the Johnson–Cook constitutive model and the finite element method to develop armature models of aluminum matrix composites with varying heterogeneous graphene volume fractions.The temperature,stress,and strain of the armatures during operation were analyzed to investigate the effects of different graphene volume fractions on the deformation and damage behavior of aluminum matrix composite armatures under the multi-field coupling of electromagnetic,thermal,and structural interactions.The results indicate that,compared to the 6061 aluminum alloy matrix,the graphene-reinforced aluminum matrix composite armature significantly suppresses ablation damage at the tail and throat edges.The incorporation of graphene notably reduces the temperature rise during the armature emission process,increases the muzzle velocity under identical current excitation,and mitigates directional deformation of the armature.The 1 wt.% graphene-reinforced aluminum matrix composite armature demonstrates better agreement with experimental results at a strain rate of 2000 s^(-1),while simultaneously improving stress-strain response,reducing temperature rise,and improving velocity performance.
基金Funded by"Green Construction and Maintenance of Road Engineering"the Belt and Road Joint Laboratory,International(Hong Kong,Macao and Taiwan)Science and Technology Cooperation Project(No.Z251100007125040)the National Key R&D Program of China(No.2022YFC3803403)+3 种基金the Project of Construction and Support for High-level Innovative Teams of Beijing Municipal Institutions(No.BPHR20220109)the Cultivation Project Funds for Beijing University of Civil Engineering and Architecture(No.X24013)the BUCEA Doctor Graduate Scientific Research Ability Improvement Project(No.DG2024016)the China Scholarship Council(No.202408110091)。
文摘A comprehensive full-sieve-hole grading correction method was used to adjust aggregate gradings.The fatigue properties of recycled concrete aggregate(RCA)asphalt mixtures were investigated using an improved indirect tensile fatigue test under temperature-humidity coupling based on 20-year meteorological data of Beijing,and the degeneration mechanism was further explored by scanning electron microscopy and energy-dispersive spectroscopy.The experimental results indicate that replacing 5-20 mm coarse limestone aggregate(LA)with RCA at a 50% substitution volume can mitigate the impact of RCA variations on the asphalt mixture proportioning design.All RCA asphalt mixtures have lower initial fatigue properties than the LA asphalt mixture.However,under temperature-humidity coupling,the long-term fatigue property of an RCA asphalt mixture with a low proportion of recycled brick exceeds that of the LA asphalt mixture,and the fatigue life decline rate of the RCA asphalt mixture during 10-year service decreases by approximately 25%.This is due to the penetration of the asphalt mortar into the RCA through the pores and cracks on the RCA surface.It forms an interfacial transition zone composed of asphalt mortar and cement mortar and further reduces the mixture damage caused by the water and freeze-thaw conditions.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3005603-01)the Natural Science Foundation Science of Anhui Province(Grant No.2308085US02).
文摘Hydraulic asphalt concrete(HAC)has been increasingly employed as an appropriate impervious structure in hydraulic and hydropower engineering.However,asphalt mortar,usually seen as the matrix of HAC composite,is particularly prone to damage under combined stress and seepage interactions,and the mesoscale investigations on the damage-seepage coupling behavior of HAC under complex stress states remain limited.This research develops a numerical three-dimensional mesoscale model composed of asphalt mortar and polyhedral aggregate to investigate the stress-damage-seepage coupling behavior in HAC.In this model,asphalt mortar yields the viscoelastic continuum damage law and aggregate obeys the Mazars’elastic-brittle damage law;simultaneously,the effective permeability coefficient of asphalt mortar is assumed to follow an exponential function of damage.The predicted deviatoric stress-strain and hydraulic gradient-seepage curves both are in good agreement with the reported experimental results,which shows the proposed model is valid and reasonable.The simulated results indicate that the damaged asphalt mortar can induce localized areas of high permeability,which in turn affects the overall impervious performance of HAC.
