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
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
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
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
The axle box bearings of high-speed trains often operate in extremely harsh environments,bearing loads from different directions.Long-term operation and frequent changes in working conditions can easily lead to axle b...The axle box bearings of high-speed trains often operate in extremely harsh environments,bearing loads from different directions.Long-term operation and frequent changes in working conditions can easily lead to axle box bearing failures.Therefore,it is extremely important to study the mechanism of axle box bearings.Firstly,the medium of thermal deformation establishes a coupling relationship between the system dynamics model and the thermal grid model,and then obtains the thermal force coupling model of the high-speed train axle box bearing.The coupling model is validated from the perspectives of system dynamics response and temperature response,proving its effectiveness in system dynamics response and temperature characteristic response.Comparing the coupling model with the dynamics model,it is found that thermal deformation complicates the dynamic re-sponse.Finally,using the Lundberg-Palmgren(L-P)bearing fatigue calculation method and damage accumu-lation theory,the bearing fatigue life is calculated,and it is found that thermal deformation deteriorates the bearing operating environment,reducing the bearing fatigue life.Finally,by comparing the bearing fatigue life under different working conditions,it is concluded that the faster the vehicle speed,the greater the load,and the smaller the initial radial clearance of the bearing,the fatigue life of the bearing is reduced.The shorter the lifespan.展开更多
To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrat...To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.展开更多
There is a strong coupling relationship between the friction characteristics of the ball-groove interface and the ball motion behavior.However,available studies tend to consider ball motion and frictional behavior sep...There is a strong coupling relationship between the friction characteristics of the ball-groove interface and the ball motion behavior.However,available studies tend to consider ball motion and frictional behavior separately.In this paper,a unified tribology-kinematic model is established considering the coupling effect between friction and the ball velocity vector.The friction in ball-groove contact and ball speed are simultaneously measured by a newly developed disc-ball-disc device for studying friction and movement in ball screws.A comprehensive analysis of rubbing interface behavior and ball motion is conducted.The results show that the coupling effect between friction in ball-groove contact and ball motion is quite obvious.The sliding velocity of the ball is much higher with coupling effect than that when ignoring coupling influence,especially at high-speed conditions.The friction in ball-groove contact decreases at first and then shows a dramatic increase with the gradual rise of rotation speed,which is caused by the coupling variation of sliding speed.The studies show that the disc-ball-disc approach is an innovative and valuable method to investigate friction and ball motion in ball screws.展开更多
Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant paramete...Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.展开更多
[Objective]This study aims to investigate the multi-body hydrodynamic interaction mechanisms during offshore lifting operations of aquaculture net cages in wind-fishery integration systems.By integrating numerical sim...[Objective]This study aims to investigate the multi-body hydrodynamic interaction mechanisms during offshore lifting operations of aquaculture net cages in wind-fishery integration systems.By integrating numerical simulations and dynamic analysis methods,this study systematically investigates the coupled dynamic response characteristics during the cage-carrier vessel separation process to reveal its dynamic evolution patterns and key influence mechanisms.[Method]Based on potential flow theory,a fully coupled dynamic analysis model of crane vessel-net cage-semi-submersible barge was established for a marine ranch project in Guangdong.The complete lifting process was dynamically simulated using SESAM software.Five typical operating sea states were configured to investigate the influence of wave parameters on the system's motion response under combined wave-current-wind actions.[Result]The results demonstrate that wave period dominates the system stability.Under short-period conditions,the system maintains stable motion with relatively small horizontal relative displacements,while long-period conditions excite low-frequency resonance,leading to significant slow-drift motions.Vertical response analysis reveals that long-period waves cause severe relative displacement fluctuations between the cage and semi-submersible vessel,with actual displacement amplitudes doubling the preset safety target of 2.045 m.Quantitative analysis further indicates that when significant wave height increases from 1.0 m to 1.5 m,the actual displacement amplitude increases by approximately 20%relative to the target displacement of 2.045 m,demonstrating that its influence is significantly weaker than the displacement variations induced by wave period changes.The complete dynamic simulation successfully captures the continuous dynamic response characteristics during the lifting process.[Conclusion]This research clarifies the influence mechanisms of wave parameters on the cage lifting process,identifying wave period as the crucial factor for operational safety.An operation window assessment method incorporating multi-body coupling effects is established,proposing a safety criterion with peak period not exceeding six seconds as the core requirement.The findings provide theoretical foundation for safe installation of marine ranch net cages and offer valuable references for similar offshore lifting operations.展开更多
Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical cra...Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical crack under combined mechanical and electric loading,considering both central and edge cracks.Using Fourier transforms and dislocation density functions,the Mode-Ⅲproblem is converted to Cauchy-type singular integral equations.The crack surface fields,intensity factors,and energy release rate are derived.The accuracy of the proposed model is verified through the finite element(FE)simulation via COMSOL Multiphysics.The results for low electron concentrations align with those of the intrinsic piezoelectric materials,validating the correctness of the present model as well.The combined effects of crack position,applied electric loading,and initial carrier concentration on the crack propagation are analyzed.The normalized electric displacement factor shows heightened sensitivity to crack size,electromechanical loading,and carrier concentration.The crack position significantly influences the crack surface fields and normalized intensity factors due to the boundary proximity effect.展开更多
Cuprous oxide(Cu_(2)O) is one of the most promising catalysts for electrochemical conversion of CO_(2) into value-added C_(2) products.The efficiency of CO_(2)-to-C_(2) conversion is highly dependent on the Cu_(2)O cr...Cuprous oxide(Cu_(2)O) is one of the most promising catalysts for electrochemical conversion of CO_(2) into value-added C_(2) products.The efficiency of CO_(2)-to-C_(2) conversion is highly dependent on the Cu_(2)O crystal plane orientation and the corresponding adsorbed ^(*)CO species.Herein,we constructed high-index crystal planes(311) in Cu_(2)O(CO-Cu_(2)O) via a facile self-selective CO-induced strategy under a CO atmosphere,which was verified by high-resolution transmission electron microscopy(HR-TEM) and atomic force microscopy(AFM) results.By exploiting the high surface energy of the high index crystal planes,^(*)CO species are stabilized in CO-Cu_(2)O during CO_(2)RR,resulting in exceptional catalytic performance for CO_(2)-to-C_(2)products.In situ infrared spectroscopy revealed that both atop-type(^(*)CO_(atop)) and hollow-type(^(*)CO_(hollow)) adsorption of ^(*)CO species occurred on the CO-Cu_(2)O.The asymmetric C-C coupling energy barrier between ^(*)CO_(atop) and ^(*)CO_(hollow) in(311) crystal plane decreases by 47.8 % compared to the symmetric coupling of ^(*)CO_(atop) in conventional(100) crystal planes.Consequently,the Faradaic efficiency of C_(2) products generated with CO-Cu_(2)O was increased by as high as 100 % compared to that with pristine Cu_(2)O.展开更多
Hydrogen,as a zero-carbon secondary energy carrier,provides a unified pathway for low-carbon energy transformation.In electro–hydrogen coupling systems(EHCSs),surplus renewable power is stored via water electrolysis ...Hydrogen,as a zero-carbon secondary energy carrier,provides a unified pathway for low-carbon energy transformation.In electro–hydrogen coupling systems(EHCSs),surplus renewable power is stored via water electrolysis and later reconverted to electricity using fuel cells or gas turbines,enhancing the system’s flexibility and reliability in support of deep decarbonization.This study constructs an electricity–hydrogen energy-recycling model based on a coupling relationship considering the bidirectional conversion between electricity and hydrogen.A multistage carbon-emission-reduction indicator constraint is also established.Additionally,the green-certificate and carbon trading markets are introduced to optimize equipment investment and operation costs while achieving carbon-emission reduction.A case study reveals that the proposed EHCS planning model effectively allocates carbon emissions across different system stages,while mitigating economic repercussions,thus ensuring closer alignment with China’s emission-reduction policies.Incorporating diverse market mechanisms significantly enhances the system’s economy and decision-making flexibility,particularly in addressing future challenges in the energy market.展开更多
Since the United Nations launched the Sustainable Development Goals(SDGs)in 2015,global implementation has steadily advanced,yet prominent challenges persist.Progress has been uneven across regions and countries,with ...Since the United Nations launched the Sustainable Development Goals(SDGs)in 2015,global implementation has steadily advanced,yet prominent challenges persist.Progress has been uneven across regions and countries,with Tajikistan representing a typical example of such disparities.Based on 81 SDG indicators for Tajikistan from 2001 to 2023,this study applied a three-level coupling network framework:at the microscale,it identified synergies and trade-offs between indicators;at the mesoscale,it examined the strength and direction of linkages within four SDG-related components(society,finance,governance,and environment);and at the global level,it focused on the overall SDG interlinkages.Spearman’s rank correlation,sliding window method,and topological properties were employed to analyze the coupling dynamics of SDGs.Results showed that over 70.00%of associations in the global SDG network were of medium-to-low intensity,alongside extremely strong ones(|r|value approached 1.00,where r is the correlation coefficient).SDG interactions were generally limited,with stable local synergy clusters in core livelihood sectors.Network modularity fluctuated,reflecting a cycle of differentiation,integration,and fragmentation,while coupling efficiency varied with the external environment.Each component exhibited distinct functional characteristics.The social component maintained high connectivity through the“poverty alleviation-education-healthcare”loop.The environmental component shifted toward coordinated eco-economic governance.The governance-related component broke interdepartmental barriers,while the financial component showed weak links between resource-based indicators and consumption/employment indicators.Tajikistan’s SDG coupling evolved through three phases:survival-oriented(2001–2012),policy integration(2013–2018),and shock adaptation(2019–2023).These phases were driven by policy changes,resource industries,governance optimization,and external factors.This study enriches the analytical framework for understanding the dynamic coupling of SDGs in mountainous resource-dependent countries and provides empirical evidence to support similar countries in formulating phase-specific SDG promotion strategies.展开更多
This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SE...This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SEM),which is used to simulate low-frequency ground motion(f<1 Hz)by incorporating an innovative efficient discontinuous Galerkin(DG)method for grid division to accurately model basin sedimentary layers at reduced costs.It also introduces a comprehensive hybrid source model for high-frequency random scattering and a nonlinear analysis module for basin sedimentary layers.Deterministic outcomes are combined with modified three-dimensional stochastic finite fault method(3D-EXSIM)simulations of high-frequency ground motion(f>1 Hz).A fourth-order Butterworth filter with zero phase shift is employed for time-domain filtering of low-and high-frequency time series at a crossover frequency of 1 Hz,merging the low and high-frequency ground motions into a broadband time series.Taking an Ms 6.8 Luding earthquake,as an example,this hybrid method was used for a rapid and efficient simulation analysis of broadband ground motion in the region.The accuracy and efficiency of this hybrid method were verified through comparisons with actually observed station data and empirical attenuation curves.Deterministic method simulation results revealed the effects of mountainous topography,basin effects,nonlinear effects within the basin’s sedimentary layers,and a coupling interaction between the basin and the mountains.The findings are consistent with similar studies,showing that near-fault sedimentary basins significantly focus and amplify strong ground motion,and the soil’s nonlinear behavior in the basin influences ground motion to varying extents at different distances from the fault.The mountainous topography impacts the basin’s response to ground motion,leading to barrier effects.This research provides a scientific foundation for seismic zoning,urban planning,and seismic design in nearfault mountain basin regions.展开更多
To address the challenges of high energy consumption and prominent costs in the traditional three-columns distillation process for cellulosic fuel ethanol,a distillation–molecular sieve coupling separation process is...To address the challenges of high energy consumption and prominent costs in the traditional three-columns distillation process for cellulosic fuel ethanol,a distillation–molecular sieve coupling separation process is proposed.This process integrates a three-column(crude distillation column,first distillation column,second distillation column)system with a 3A molecular sieve adsorption deep dehydration unit.A thermal coupling network is constructed via differential pressure design(steam from medium/high-pressure columns as mutual heat sources,reboiler liquid waste heat for feed preheating),and molecular sieve adsorption conditions are optimized.The study first performs a thermodynamic consistency test on the ethanol–water system,determines optimal non-random two-liquid(NRTL)model binary interaction parameters via experimental data regression for Aspen Plus simulation.Aiming at minimum total annual cost(TAC),Aspen Plus is used to optimize process parameters(theoretical tray number,feed location,reflux ratio,side-draw position,etc.).Economic analysis shows this process reduces CO_(2) emission costs by 27.56%,TAC by 15.58%(to 5.123×10^(6) USD·a^(−1)),and increases ethanol purity to>99.6%,providing an effective solution for green,efficient separation.展开更多
In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitud...In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitudinal strong focusing(GLSF).At present,GLSF is the most promising method for realizing high-power short-wavelength coherent radiation with mild requirements on modulation laser power.Its essence is to exploit the ultrasmall natural vertical emittance of an electron beam in a planar storage ring for efficient microbunching formation,like a partial transverse-longitudinal emittance exchange in the optical laser wavelength range.Based on an in-depth investigation of related beam physics,a solution for a GLSF SSMB storage ring that can deliver 1 kW average-power EUV light is presented.The work in this paper,such as the generalized Courant–Snyder formalism,analysis of theoretical minimum emittances,transverse-longitudinal coupling dynamics,and derivation of the bunching factor and modulation strengths for laser-induced microbunching schemes,is expected to be useful not only for the development of SSMB but also for future accelerator light sources in general that demand increasingly precise electron beam phase space manipulations.展开更多
Developing advanced electrocatalysts to convert CO_(2) into liquid fuels such as C_(2)H_(5)OH is critical for utilizing intermittent renewable energy.The formation of C_(2)H_(5)OH,however,is generally less favored com...Developing advanced electrocatalysts to convert CO_(2) into liquid fuels such as C_(2)H_(5)OH is critical for utilizing intermittent renewable energy.The formation of C_(2)H_(5)OH,however,is generally less favored compared with the other hydrocarbon products from Cu-based electrocatalysts.In this work,an alkanethiolmodified Cu_(2)O nanowire array(OTT-Cu_(2)O) was constructed with asymmetric Cu sites consisting of paired Cu-O and Cu-S motifs to overcome previous limitations of C_(2)H_(5)OH electrosynthesis via CO_(2)RR pathway.This catalyst achieves a high Faradaic efficiency of 45 % for CO_(2)-to-C_(2)H_(5)OH conversion at 300 m A/cm^(2),representing a more than two-fold enhancement over the Cu_(2)O electrode.Mechanistic investigations reveal that the Cu-S site exhibits distinct C-binding capability that stabilizes key intermediates(^(*)OCH_(2) and ^(*)CO),in contrast to the O-affinitive Cu-O site.The asymmetric S-Cu-O configuration promotes thermodynamically favorable asymmetric C-C coupling between ^(*)CO and ^(*)OCH_(2),forming the critical CO-OCH_(2) intermediate and facilitating C_(2)H_(5)OH production,as opposed to symmetric O-Cu-O sites that mainly generate HCOOH.This work offers an effective strategy for designing multi-active-site catalysts toward highly selective CO_(2) reduction to C_(2)H_(5)OH and provides fundamental insight into the reaction mechanism.展开更多
Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,how...Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,however,constrain their delicate constructions.Herein,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix.This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial polarization.Such“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time.Consequently,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric response.Harnessing defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.展开更多
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.”
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Supported by the National Natural Science Foundation of China(Grant Nos.12393780,12032017,12302067)College Education Scientific Research Project of Hebei Province(Grant No.JZX2024006)Hebei Provincial S&T Program(Grant No.21567622 H).
文摘The axle box bearings of high-speed trains often operate in extremely harsh environments,bearing loads from different directions.Long-term operation and frequent changes in working conditions can easily lead to axle box bearing failures.Therefore,it is extremely important to study the mechanism of axle box bearings.Firstly,the medium of thermal deformation establishes a coupling relationship between the system dynamics model and the thermal grid model,and then obtains the thermal force coupling model of the high-speed train axle box bearing.The coupling model is validated from the perspectives of system dynamics response and temperature response,proving its effectiveness in system dynamics response and temperature characteristic response.Comparing the coupling model with the dynamics model,it is found that thermal deformation complicates the dynamic re-sponse.Finally,using the Lundberg-Palmgren(L-P)bearing fatigue calculation method and damage accumu-lation theory,the bearing fatigue life is calculated,and it is found that thermal deformation deteriorates the bearing operating environment,reducing the bearing fatigue life.Finally,by comparing the bearing fatigue life under different working conditions,it is concluded that the faster the vehicle speed,the greater the load,and the smaller the initial radial clearance of the bearing,the fatigue life of the bearing is reduced.The shorter the lifespan.
基金supported by the National Key Research and Development Program of China(No.2022YFF1301301)the Natural Science Foundation of Xiamen Municipality(No.3502Z202472047)the Geological Survey Program of China Geological Survey(DD20190303).
文摘To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.
基金Supported by National Natural Science Foundation of China(Grant No.52275206).
文摘There is a strong coupling relationship between the friction characteristics of the ball-groove interface and the ball motion behavior.However,available studies tend to consider ball motion and frictional behavior separately.In this paper,a unified tribology-kinematic model is established considering the coupling effect between friction and the ball velocity vector.The friction in ball-groove contact and ball speed are simultaneously measured by a newly developed disc-ball-disc device for studying friction and movement in ball screws.A comprehensive analysis of rubbing interface behavior and ball motion is conducted.The results show that the coupling effect between friction in ball-groove contact and ball motion is quite obvious.The sliding velocity of the ball is much higher with coupling effect than that when ignoring coupling influence,especially at high-speed conditions.The friction in ball-groove contact decreases at first and then shows a dramatic increase with the gradual rise of rotation speed,which is caused by the coupling variation of sliding speed.The studies show that the disc-ball-disc approach is an innovative and valuable method to investigate friction and ball motion in ball screws.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFC2200100)the CAS's Strategic Pioneer Program on Space Science(Grant No.XDA1502110201)。
文摘Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.
文摘[Objective]This study aims to investigate the multi-body hydrodynamic interaction mechanisms during offshore lifting operations of aquaculture net cages in wind-fishery integration systems.By integrating numerical simulations and dynamic analysis methods,this study systematically investigates the coupled dynamic response characteristics during the cage-carrier vessel separation process to reveal its dynamic evolution patterns and key influence mechanisms.[Method]Based on potential flow theory,a fully coupled dynamic analysis model of crane vessel-net cage-semi-submersible barge was established for a marine ranch project in Guangdong.The complete lifting process was dynamically simulated using SESAM software.Five typical operating sea states were configured to investigate the influence of wave parameters on the system's motion response under combined wave-current-wind actions.[Result]The results demonstrate that wave period dominates the system stability.Under short-period conditions,the system maintains stable motion with relatively small horizontal relative displacements,while long-period conditions excite low-frequency resonance,leading to significant slow-drift motions.Vertical response analysis reveals that long-period waves cause severe relative displacement fluctuations between the cage and semi-submersible vessel,with actual displacement amplitudes doubling the preset safety target of 2.045 m.Quantitative analysis further indicates that when significant wave height increases from 1.0 m to 1.5 m,the actual displacement amplitude increases by approximately 20%relative to the target displacement of 2.045 m,demonstrating that its influence is significantly weaker than the displacement variations induced by wave period changes.The complete dynamic simulation successfully captures the continuous dynamic response characteristics during the lifting process.[Conclusion]This research clarifies the influence mechanisms of wave parameters on the cage lifting process,identifying wave period as the crucial factor for operational safety.An operation window assessment method incorporating multi-body coupling effects is established,proposing a safety criterion with peak period not exceeding six seconds as the core requirement.The findings provide theoretical foundation for safe installation of marine ranch net cages and offer valuable references for similar offshore lifting operations.
基金Project supported by the Guangdong Basic and Applied Basic Research Foundation of China(Nos.2022B1515020099 and 2024A1515240026)the National Natural Science Foundation of China(No.12372147)the Fundamental Research Funds for the Central Universities of China(No.HIT.OCEF.2024019)。
文摘Understanding the fracture behavior of vertical cracks in piezoelectric semiconductor(PS)structures is vital due to their impacts on device reliability.This study establishes a model for a PS strip with a vertical crack under combined mechanical and electric loading,considering both central and edge cracks.Using Fourier transforms and dislocation density functions,the Mode-Ⅲproblem is converted to Cauchy-type singular integral equations.The crack surface fields,intensity factors,and energy release rate are derived.The accuracy of the proposed model is verified through the finite element(FE)simulation via COMSOL Multiphysics.The results for low electron concentrations align with those of the intrinsic piezoelectric materials,validating the correctness of the present model as well.The combined effects of crack position,applied electric loading,and initial carrier concentration on the crack propagation are analyzed.The normalized electric displacement factor shows heightened sensitivity to crack size,electromechanical loading,and carrier concentration.The crack position significantly influences the crack surface fields and normalized intensity factors due to the boundary proximity effect.
基金the financial support from the National Natural Science Foundation of China (Nos.U23A20677,22022610 and 52400137)"Pioneer" and "Leading Goose" R&D Program of Zhejiang (Nos.2022C03146 and 2023C03017)+2 种基金China Postdoctoral Science Foundation (No.2024T170805)Zhejiang Provincial Natural Science Foundation of China (No.LDT23E06015B06)the support of the Research Computing Center in College of Chemical and Biological Engineering at Zhejiang University for assistance with the calculations。
文摘Cuprous oxide(Cu_(2)O) is one of the most promising catalysts for electrochemical conversion of CO_(2) into value-added C_(2) products.The efficiency of CO_(2)-to-C_(2) conversion is highly dependent on the Cu_(2)O crystal plane orientation and the corresponding adsorbed ^(*)CO species.Herein,we constructed high-index crystal planes(311) in Cu_(2)O(CO-Cu_(2)O) via a facile self-selective CO-induced strategy under a CO atmosphere,which was verified by high-resolution transmission electron microscopy(HR-TEM) and atomic force microscopy(AFM) results.By exploiting the high surface energy of the high index crystal planes,^(*)CO species are stabilized in CO-Cu_(2)O during CO_(2)RR,resulting in exceptional catalytic performance for CO_(2)-to-C_(2)products.In situ infrared spectroscopy revealed that both atop-type(^(*)CO_(atop)) and hollow-type(^(*)CO_(hollow)) adsorption of ^(*)CO species occurred on the CO-Cu_(2)O.The asymmetric C-C coupling energy barrier between ^(*)CO_(atop) and ^(*)CO_(hollow) in(311) crystal plane decreases by 47.8 % compared to the symmetric coupling of ^(*)CO_(atop) in conventional(100) crystal planes.Consequently,the Faradaic efficiency of C_(2) products generated with CO-Cu_(2)O was increased by as high as 100 % compared to that with pristine Cu_(2)O.
基金supported by State Grid Jiangsu Electric Power Co.,Ltd.Technology Project(Research on Planning and Operation Technology of Electric–Hydrogen Coupling System Driven by the Electric–Carbon–Green Certificate Market):J2024005.
文摘Hydrogen,as a zero-carbon secondary energy carrier,provides a unified pathway for low-carbon energy transformation.In electro–hydrogen coupling systems(EHCSs),surplus renewable power is stored via water electrolysis and later reconverted to electricity using fuel cells or gas turbines,enhancing the system’s flexibility and reliability in support of deep decarbonization.This study constructs an electricity–hydrogen energy-recycling model based on a coupling relationship considering the bidirectional conversion between electricity and hydrogen.A multistage carbon-emission-reduction indicator constraint is also established.Additionally,the green-certificate and carbon trading markets are introduced to optimize equipment investment and operation costs while achieving carbon-emission reduction.A case study reveals that the proposed EHCS planning model effectively allocates carbon emissions across different system stages,while mitigating economic repercussions,thus ensuring closer alignment with China’s emission-reduction policies.Incorporating diverse market mechanisms significantly enhances the system’s economy and decision-making flexibility,particularly in addressing future challenges in the energy market.
文摘Since the United Nations launched the Sustainable Development Goals(SDGs)in 2015,global implementation has steadily advanced,yet prominent challenges persist.Progress has been uneven across regions and countries,with Tajikistan representing a typical example of such disparities.Based on 81 SDG indicators for Tajikistan from 2001 to 2023,this study applied a three-level coupling network framework:at the microscale,it identified synergies and trade-offs between indicators;at the mesoscale,it examined the strength and direction of linkages within four SDG-related components(society,finance,governance,and environment);and at the global level,it focused on the overall SDG interlinkages.Spearman’s rank correlation,sliding window method,and topological properties were employed to analyze the coupling dynamics of SDGs.Results showed that over 70.00%of associations in the global SDG network were of medium-to-low intensity,alongside extremely strong ones(|r|value approached 1.00,where r is the correlation coefficient).SDG interactions were generally limited,with stable local synergy clusters in core livelihood sectors.Network modularity fluctuated,reflecting a cycle of differentiation,integration,and fragmentation,while coupling efficiency varied with the external environment.Each component exhibited distinct functional characteristics.The social component maintained high connectivity through the“poverty alleviation-education-healthcare”loop.The environmental component shifted toward coordinated eco-economic governance.The governance-related component broke interdepartmental barriers,while the financial component showed weak links between resource-based indicators and consumption/employment indicators.Tajikistan’s SDG coupling evolved through three phases:survival-oriented(2001–2012),policy integration(2013–2018),and shock adaptation(2019–2023).These phases were driven by policy changes,resource industries,governance optimization,and external factors.This study enriches the analytical framework for understanding the dynamic coupling of SDGs in mountainous resource-dependent countries and provides empirical evidence to support similar countries in formulating phase-specific SDG promotion strategies.
基金National Natural Science Foundation of China under Grant Nos.U2139208 and 52278516Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration under Grant No.2024D15Key Laboratory of Soft Soil Characteristic and Engineering Environment,Tianjin Chengjian University under Grant No.2022SCEEKL003。
文摘This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SEM),which is used to simulate low-frequency ground motion(f<1 Hz)by incorporating an innovative efficient discontinuous Galerkin(DG)method for grid division to accurately model basin sedimentary layers at reduced costs.It also introduces a comprehensive hybrid source model for high-frequency random scattering and a nonlinear analysis module for basin sedimentary layers.Deterministic outcomes are combined with modified three-dimensional stochastic finite fault method(3D-EXSIM)simulations of high-frequency ground motion(f>1 Hz).A fourth-order Butterworth filter with zero phase shift is employed for time-domain filtering of low-and high-frequency time series at a crossover frequency of 1 Hz,merging the low and high-frequency ground motions into a broadband time series.Taking an Ms 6.8 Luding earthquake,as an example,this hybrid method was used for a rapid and efficient simulation analysis of broadband ground motion in the region.The accuracy and efficiency of this hybrid method were verified through comparisons with actually observed station data and empirical attenuation curves.Deterministic method simulation results revealed the effects of mountainous topography,basin effects,nonlinear effects within the basin’s sedimentary layers,and a coupling interaction between the basin and the mountains.The findings are consistent with similar studies,showing that near-fault sedimentary basins significantly focus and amplify strong ground motion,and the soil’s nonlinear behavior in the basin influences ground motion to varying extents at different distances from the fault.The mountainous topography impacts the basin’s response to ground motion,leading to barrier effects.This research provides a scientific foundation for seismic zoning,urban planning,and seismic design in nearfault mountain basin regions.
基金support from the National Key Research and Development Program of China(2022YFC2106300)the National Natural Science Foundation of China(42177400).
文摘To address the challenges of high energy consumption and prominent costs in the traditional three-columns distillation process for cellulosic fuel ethanol,a distillation–molecular sieve coupling separation process is proposed.This process integrates a three-column(crude distillation column,first distillation column,second distillation column)system with a 3A molecular sieve adsorption deep dehydration unit.A thermal coupling network is constructed via differential pressure design(steam from medium/high-pressure columns as mutual heat sources,reboiler liquid waste heat for feed preheating),and molecular sieve adsorption conditions are optimized.The study first performs a thermodynamic consistency test on the ethanol–water system,determines optimal non-random two-liquid(NRTL)model binary interaction parameters via experimental data regression for Aspen Plus simulation.Aiming at minimum total annual cost(TAC),Aspen Plus is used to optimize process parameters(theoretical tray number,feed location,reflux ratio,side-draw position,etc.).Economic analysis shows this process reduces CO_(2) emission costs by 27.56%,TAC by 15.58%(to 5.123×10^(6) USD·a^(−1)),and increases ethanol purity to>99.6%,providing an effective solution for green,efficient separation.
基金supported by the National Key Research and Development Program of China(No.2022YFA1603401)National Natural Science Foundation of China(Nos.12035010 and 12342501)+1 种基金Beijing Outstanding Young Scientist Program(No.JWZQ20240101006)the Tsinghua University Dushi Program.
文摘In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitudinal strong focusing(GLSF).At present,GLSF is the most promising method for realizing high-power short-wavelength coherent radiation with mild requirements on modulation laser power.Its essence is to exploit the ultrasmall natural vertical emittance of an electron beam in a planar storage ring for efficient microbunching formation,like a partial transverse-longitudinal emittance exchange in the optical laser wavelength range.Based on an in-depth investigation of related beam physics,a solution for a GLSF SSMB storage ring that can deliver 1 kW average-power EUV light is presented.The work in this paper,such as the generalized Courant–Snyder formalism,analysis of theoretical minimum emittances,transverse-longitudinal coupling dynamics,and derivation of the bunching factor and modulation strengths for laser-induced microbunching schemes,is expected to be useful not only for the development of SSMB but also for future accelerator light sources in general that demand increasingly precise electron beam phase space manipulations.
基金financial supports of the National Natural Science Foundation of China (NSFC,Nos.52394202,52476056,and 52301232)the Natural Science Foundation of Chongqing Province (No.2024NSCQ-MSX1109)。
文摘Developing advanced electrocatalysts to convert CO_(2) into liquid fuels such as C_(2)H_(5)OH is critical for utilizing intermittent renewable energy.The formation of C_(2)H_(5)OH,however,is generally less favored compared with the other hydrocarbon products from Cu-based electrocatalysts.In this work,an alkanethiolmodified Cu_(2)O nanowire array(OTT-Cu_(2)O) was constructed with asymmetric Cu sites consisting of paired Cu-O and Cu-S motifs to overcome previous limitations of C_(2)H_(5)OH electrosynthesis via CO_(2)RR pathway.This catalyst achieves a high Faradaic efficiency of 45 % for CO_(2)-to-C_(2)H_(5)OH conversion at 300 m A/cm^(2),representing a more than two-fold enhancement over the Cu_(2)O electrode.Mechanistic investigations reveal that the Cu-S site exhibits distinct C-binding capability that stabilizes key intermediates(^(*)OCH_(2) and ^(*)CO),in contrast to the O-affinitive Cu-O site.The asymmetric S-Cu-O configuration promotes thermodynamically favorable asymmetric C-C coupling between ^(*)CO and ^(*)OCH_(2),forming the critical CO-OCH_(2) intermediate and facilitating C_(2)H_(5)OH production,as opposed to symmetric O-Cu-O sites that mainly generate HCOOH.This work offers an effective strategy for designing multi-active-site catalysts toward highly selective CO_(2) reduction to C_(2)H_(5)OH and provides fundamental insight into the reaction mechanism.
基金financially supported by the National Natural Science Foundation of China(Grants nos.62201411,62371378,22205168,52302150 and 62304171)the China Postdoctoral Science Foundation(2022M722500)+1 种基金the Fundamental Research Funds for the Central Universities(Grants nos.ZYTS2308 and 20103237929)Startup Foundation of Xidian University(10251220001).
文摘Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,however,constrain their delicate constructions.Herein,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix.This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial polarization.Such“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time.Consequently,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric response.Harnessing defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.
