Understanding Cd contamination in the soil-rice ecosystem and the underlying its threshold and interaction effects is crucial for controlling Cd pollution and ensuring food safety.Although the quantitative relationshi...Understanding Cd contamination in the soil-rice ecosystem and the underlying its threshold and interaction effects is crucial for controlling Cd pollution and ensuring food safety.Although the quantitative relationships between Cd and environmental variables have been extensively studied,the threshold and interaction effects of multi-source environmental variables remain largely unexplored.This study employs a combination of random forest analysis and a human health risk model to investigate the effects of variables on Cd levels in rice grains,with the goal of quantifying their contributions and elucidating their relationships.The results indicated that the 15 selected variables collectively explained 47.36%of the variation in Cd content,with the top three variables being soil pH,distance from industrial park,and soil Zn.The majority of variables exhibited threshold effects on Cd levels in rice grains.By visualizing the interaction between Soil pH,distance from industrial park,and soil Zn with Cd levels in rice,we demonstrate the threshold effects of them on Cd level in rice grains,thereby providing further insight into the variation observed.Furthermore,oral intake of rice has been identified as the primary route of human exposure,significantly contributing to overall exposure pathways.Understanding these interactions is crucial for gaining insights into the underlying processes driving Cd pollution and fostering sustainable development within the industry.Our findings underscore the crucial need to consider multiple environmental variables and their interactions when managing heavy metals(HMs)contamination and mitigating health risks.展开更多
This study synthesized a high-strength Zr42Ti15Nb20Ta20Al3(at.%)refractory high-entropy alloy(RHEA)via vacuum induction melting.The mechanical behavior of the Zr42Ti15Nb_(2 n)Ta_(2 n)Al3RHEA wa...This study synthesized a high-strength Zr42Ti15Nb20Ta20Al3(at.%)refractory high-entropy alloy(RHEA)via vacuum induction melting.The mechanical behavior of the Zr42Ti15Nb_(2 n)Ta_(2 n)Al3RHEA was systematically investigated through a universal testing machine and split Hopkinson pressure bar system at strain rates up to 5100 s−1,and the temperature change is from 193 K to 673 K.By integrating theoretical derivation and microstructural characterization,we examined the mechanical behavior and deformation mechanisms of the Zr42Ti15Nb_(2 n)Ta_(2 n)Al3RHEA under the synergistic effects of temperature and strain rate.The results demonstrate that the Zr42Ti15Nb_(2 n)Ta_(2 n)Al3RHEA exhibits a significant positive strain rate effect.The dominant deformation mechanism changes with increasing strain rate:cross-slip→localized shear→adiabatic shear.When the strain rate reaches 5100 s−1,the yield strength increases from 1151 MPa to 2112 MPa,and an adiabatic shear band forms.Simultaneously,the microstructure undergoes severe localized deformation,dominated by shear bands,and dynamic recrystallization(DRX)is activated to counteract the deformation.At 193 K,the yield strength is 2241 MPa.Kink bands have appeared,enhancing the ductility of RHEA:the yield strength and the temperature sensitivity coefficient decrease with increasing temperature.However,as the temperature increases,atomic mobility is enhanced,which promotes grain boundary sliding and migration,activating DRX,and effectively mitigating shear localization.This study deepens our understanding of the mechanical properties and deformation mechanisms of the Zr42Ti15Nb20Ta20Al3RHEA.It reveals the microstructure evolution process of the alloy under different strain rates,the synergistic effect of strain rate and temperature,and the influence of strain rate and temperature on the deformation mechanisms of the material.This research lays a theoretical foundation for applying the Zr42Ti15Nb20Ta20Al3RHEA in extreme environments.展开更多
Ensuring national food security amidst rapid population growth and increasing extreme weather events remains a critical global challenge.However,the extent to which agricultural modernization in China enhances grain y...Ensuring national food security amidst rapid population growth and increasing extreme weather events remains a critical global challenge.However,the extent to which agricultural modernization in China enhances grain yield and contributes to food security remains unclear.Therefore,using panel data from 327 Chinese cities(2013–2021),this study employs spatial econometric models to analyze the spatial spillover effects of agricultural modernization level(AML)on grain yield and to reveal regional heterogeneity across nine major agricultural zones.The results showed a cumulative grain yield increase of 23.7 million tons,with peak productivity concentrated along the Hu Line and declining eastward and westward.AML also exhibited a steady increase but a clear spatial gradient,decreasing from coastal to inland regions,with the highest level observed in Southern China(SC).A key finding was that a 1%increase in AML directly raised local grain yield by an average of 4.185%,accompanied by significant positive spillover effects on neighboring regions.Regional variations revealed distinct patterns:the direct effects of AML were more pronounced in southern and eastern zones,while spillover effects dominated in northern and western zones.The largest positive direct impact of AML on grain yield was observed in the SC(8.499%),while Middle-Lower Yangtze Plain ranked second but exhibited the strongest positive spatial spillover effect(4.534%).These findings highlight the critical role of agricultural modernization in promoting grain production and provide a solid basis for optimizing regional agricultural systems,ensuring food security,and advancing sustainable agriculture.展开更多
This research provides analytical solutions to assess the bending-torsional vibration behavior of a thin-walled box girder subjected to moving random loads.The governing equations of a thin-walled box girder have been...This research provides analytical solutions to assess the bending-torsional vibration behavior of a thin-walled box girder subjected to moving random loads.The governing equations of a thin-walled box girder have been formulated to incorporate the impact of shear effect.The technique of integral transformation and the method of statistical analysis are employed to determine the average and standard deviation of the displacements at mid-span.The research’s findings are compared with the results from the Newmark-βtechnique and the Monte Carlo method to validate the effectiveness of the proposed strategy.By analysing the parameters,it is confirmed that neglecting the shear effect can result in substantial underestimation of lateral displacement.Compared to the Euler-Bernoulli beam theory,which does not consider the shear effect,the proposed theory shows differences of up to 109%in the average value and 213%in the standard deviation.These analysis results provide a reference for the vibration analysis of thin-walled box girders.展开更多
Understanding the effects of the electric double layer(EDL)on electrode kinetics is of great importance for improving the performance of electrochemical devices.In this work,by using the HER at Au(111)in x M HClO4+...Understanding the effects of the electric double layer(EDL)on electrode kinetics is of great importance for improving the performance of electrochemical devices.In this work,by using the HER at Au(111)in x M HClO4+(1-x)M NaClO4or NaOH as a model reaction,the intrinsic kinetic parameters for HER has been unveiled based on the modified Poisson-Nernst-Planck equations and the Frumkin-Butler-Volmer theory.Our analysis reveals that i)the EDL effects induced changes in proton concentration cH+RPand electric potential φRPat the reaction plane are the main reason for the difference of HER current in the cases with x M HClO4and x M HClO4+(1-x)M NaClO4;ii)the EDL effects are the main origin for the difference in HER current between acidic and alkaline solutions at the Au(111).Our work demonstrates that microkinetic simulation with properly considering the EDL effects is important for unravelling intrinsic reaction kinetics of electrocatalytic reactions.展开更多
Biomimicry provides a design framework that emulates biological characteristics to exploit their functional advantages.This study presents a biomimetic-based aerodynamic assessment of wing-in-ground(WiG)configurations...Biomimicry provides a design framework that emulates biological characteristics to exploit their functional advantages.This study presents a biomimetic-based aerodynamic assessment of wing-in-ground(WiG)configurations inspired by flying animals,including birds and mammals,using computational fluid dynamics(CFD).Three biomimetic wing models were developed by translating biological characteristics—such as body size,wing geometry,and flight behavior—into engineering design parameters relevant to near-surface flight.Numerical simulations were performed to evaluate lift,drag,lift-to-drag ratio,and trim stability under various operating conditions.The results demonstrate that each biomimetic configuration exhibits distinct aerodynamic performance consistent with its biological inspiration.The brown pelican-inspired model achieved the highest lift force,reaching approximately 68 kN,reflecting its natural adaptation for efficient lift generation near the surface.In contrast,the sugar glider-inspired model produced the lowest lift,approximately 37 kN,corresponding to its lightweight gliding characteristics.Overall,the findings confirm that biomimicry provides a rational and effective framework for preliminary WiG craft design,enabling aerodynamic performance to be systematically tailored through biologically inspired geometrical adaptations.展开更多
Electrochemical CO2 reduction reaction(CO2RR) into valuable formate provides a strategy for carbon neutrality.Bismuth(Bi) catalysts,attributed to their appropriate energy barrier of OCHO*intermediate,have demons...Electrochemical CO2 reduction reaction(CO2RR) into valuable formate provides a strategy for carbon neutrality.Bismuth(Bi) catalysts,attributed to their appropriate energy barrier of OCHO*intermediate,have demonstrated substantial potential for the advancement of electrocatalytic CO2 reduction to formate.However,due to the weak bonding of protons(H*) of Bi,the available protonate of CO2 on Bi is insufficient,which limits the formation of OCHO*.Prediction by theoretical calculation,chlorine doping can effectively promote the dissociation of H2O and thus achieve effective proton supply.We prepare chlorine-doped Bi(Cl-Bi) via an electrochemical conversion strategy for electroreduction of CO2 .An obvious improvement of faradaic efficiency(FE) of formate(96.7% at-0.95 V vs.RHE) can be achieved on Cl-Bi,higher than that of Bi(89.4%).Meanwhile,Cl-Bi has the highest formate production rate of 275 μmol h-1cm-2at-0.95 V vs.RHE,which is 1.2 times higher than that of Bi(224 μmol h-1cm-2).In situ characterizations and kinetic analysis reveal that chlorine doping promotes the activation of H2O and supply sufficient protons to promote the protonation of CO2 to OCHO*,which is consistent with theoretical calculation.The study presents an effective strategy for rational design of highly efficient electrocatalysts to promote green chemical production.展开更多
Existing studies on the Regional Comprehensive Economic Partnership(RCEP)mainly focused on institutional features,macro-economic impacts,and trade-network structures,while its geographic attributes and their implicati...Existing studies on the Regional Comprehensive Economic Partnership(RCEP)mainly focused on institutional features,macro-economic impacts,and trade-network structures,while its geographic attributes and their implications remain underexplored.Taking the RCEP as a case,this paper examines how the FTA reshapes China’s trade geography and validates these effects with an enhanced GTAP model,providing an empirical basis for advancing trade-geography theory.Key findings include:(1)RCEP significantly reduces regional trade costs.After full implementation of the agreement,the average tariffs among member countries will decrease to 40.5%of the pre-implementation level,while import and export trade facilitation levels improve by 34.3%and 29.6%,respectively.However,these improvements exhibit marked regional disparities.(2)RCEP asymmetrically promotes China’s foreign trade growth,with stronger import stimulation than export expansion,alongside significant product-specific variations.(3)The agreement reshapes China’s trade geography,driving a 7.66%increase in intra-RCEP trade while reducing extra-RCEP trade by 0.80%.(4)The restructuring of China’s trade patterns under RCEP emerges from the complex interplay of trade creation,diversion,and crowding-out effects.Accordingly,China should further harmonize regional tariff schedules,enhance trade-facilitation mechanisms,strengthen industrial competitiveness and expand multilateral partnerships.展开更多
This study integrates unconfined compression tests with high-resolution computed tomography(CT)to analyze the pore heterogeneity,crack propagation,and failure modes of red sandstone specimens with diameters ranging fr...This study integrates unconfined compression tests with high-resolution computed tomography(CT)to analyze the pore heterogeneity,crack propagation,and failure modes of red sandstone specimens with diameters ranging from 10 mm to 100 mm.Key findings include:(1)With increasing specimen size,crack initiation stress(CI),damage stress(CD),and unconfined compressive strength(UCS)initially increase and then decrease;(2)In smaller specimens,stress concentration due to pore heterogeneity leads to splitting failure and lower strength;(3)In medium-sized specimens,friction dominates crack propagation,causing shear failure,while increased fragment rotation enhances energy dissipation,yielding highest strength;(4)In larger specimens,cracks tend to propagate along bedding planes,reducing energy dissipation and then weakening strength.These results provide insights into the reverse size effect on sandstone strength and have implications for engineering applications.展开更多
Aerodynamic performances of axial compressors are significantly affected by variation of Reynolds number in aero-engines.In the design and analysis of compressors,previous correction methods for cascades and stages ha...Aerodynamic performances of axial compressors are significantly affected by variation of Reynolds number in aero-engines.In the design and analysis of compressors,previous correction methods for cascades and stages have difficulties in predicting comprehensively Reynolds number effects on airfoils,matching and characteristics curves.This study proposes Re-correction models for loss,deviation angle and endwall blockage based on classical theories and cascade tests,and loss and deviation models show good agreement in test data of NACA65 and C4 cascades.Throughflow method considering Reynolds number effects is developed by integrating the correction models into a verified Streamline Curvature(SLC)tool.A three-stage axial compressor is investigated through SLC and CFD methods from design Reynolds number(Red=2106)to low Re=4104,and the numerical methods are validated with test data of characteristic curves and spanwise distributions at Red.With Re reduction,SLC method with correction models well predicts variation in overall performances compared with CFD calculations and Wassell's model.Streamwise and spanwise matching such as total pressure and loss distributions in SLC predictions are basically consistent with those in CFD results at near-stall points under design and low Reynolds numbers.SLC and CFD methods share similar detections of stall risks in the third stage(Stg3),and their analyses of diffusion processes deviate to some extent due to different predictions in separated endwall flow.The correction models can be adopted to consider Reynolds number effects in through-flow design and analysis of axial compressors.展开更多
Dryland biodiversity–productivity relationships remain poorly resolved.Specifically,the environmental conditions governing the shift between complementarity and mass ratio mechanisms remain unclear,limiting the effec...Dryland biodiversity–productivity relationships remain poorly resolved.Specifically,the environmental conditions governing the shift between complementarity and mass ratio mechanisms remain unclear,limiting the effectiveness of restoration and management strategies.To address this gap,the aim of this study was to investigate the geographical patterns of diversity and biomass production in herbaceous communities along a 2100-km precipitation gradient in North China.We studied howα-andβ-diversity affect community-wide productivity using linear mixed-effects models and piecewise structural equation models,along with rolling-window change-point analyses.In arid regions,biomass productivity was primarily driven by interspecificniche complementarity,where higher functional diversity(FD(α))enhanced resource-use efficiency.However,in semi-arid regions,productivity was regulated by the mass ratio effect,specificallythrough the traits of dominant species,including community weighted mean height and specificleaf area,as these species exploited broader resource spectra with increasing water availability.A critical mechanistic shift occurred at a mean annual precipitation(MAP)threshold of~168 mm(95%CI:152–171 mm;p<0.001).Below this threshold,productivity was driven by diversity-mediated complementarity and stress tolerant strategies.Conversely,as MAP surpassed 168 mm,the system transitioned to mass ratio control,coincident with a shift toward competitive strategies.Overall,our study provides empirical evidence to guide dryland management:prioritising the maintenance of functional diversity in arid communities,while emphasising dominant-trait optimisation(plant height and specificleaf area)in semi-arid communities to maximise aboveground biomass.展开更多
Gas liquefiers allow efficient transport and storage of gases,key for the development of new energy vectors such as hydrogen fuel.In this sense,magnetic liquefiers based on the magnetocaloric effect are an energy-savi...Gas liquefiers allow efficient transport and storage of gases,key for the development of new energy vectors such as hydrogen fuel.In this sense,magnetic liquefiers based on the magnetocaloric effect are an energy-saving and sustainable alternative to current systems based on the Joule-Thomson expansion.Here,we report the magnetocaloric effect of light rare-earth-based Ce(La)In2 alloys near the hydrogen condensation point.They exhibit a first-order ferromagnetic to paramagnetic phase transition with reduced thermal hysteresis(0.05 K) and moderate criticality compared to their heavy rare-earth-based counterparts.Both isothermal entropy change,and adiabatic entropy change have been indirectly determined from heat capacity measurements.A previously developed method based on lowtemperature truncation of heat capacity data was applied for those calculations,accounting for ~8%underestimation of the maximum values as well as possible misinterpretations of the results in the paramagnetic range.The parent CeIn2 alloy shows an isothermal entropy change of 9.5 J/(kg·K) and an adiabatic temperature change of 2.8 K for a magnetic field change of 5 T.The substitution of Ce by La leads to a slight decrease of the transition temperature in the explored range together with a significant reduction of the magnetocaloric magnitudes:about-1.0 J/(kg·K) and about 0.2 K per atom fraction of La for the isothermal entropy and adiabatic temperature changes for 5 T,respectively.展开更多
Silicon dioxide(SiO)is regarded as a promising anode candidate for high-energy-density lithium-ion batteries(LIBs)owing to its superior theoretical specific capacity.However,SiO anodes encounter substantial challenges...Silicon dioxide(SiO)is regarded as a promising anode candidate for high-energy-density lithium-ion batteries(LIBs)owing to its superior theoretical specific capacity.However,SiO anodes encounter substantial challenges,including substantial volume expansion and persistent growth of a thick solid electrolyte interphase(SEI).In this work,a composite conductive network with dual pinning and piezoelectric effects is proposed,which is cleverly designed to improve the electrochemical reaction kinetics of the electrode.Within the proposed network architecture,single-walled carbon nanotubes(CNTs)serve as fast electronic conductors and structural protective layers,forming a three-dimensional(3D)coating network on the surface of SiO particles.Barium titanate(BTO)nanoparticles are anchored at the nodes of the CNT network through the formation of rigid anchor points,dispersing stress throughout the network.Concurrently,mechanical stress induced by electrochemical reactions prompts BTO to generate a local electric field,facilitating Li+transport.Consequently,the developed anode(SiO@PCB)demonstrates remarkable electrochemical performance in LIBs,exhibiting a capacity retention rate of 94%even after 500 cycles at 1 A g-1.Furthermore,a capacity retention of 71.6%is demonstrated by SiO@PCB anode after 1000 cycles at 5 C in sulfide-based all-solid-state LIBs using an NCM83 cathode.This composite conductive network structure provides an effective guidance plan for achieving interface stability and long-term lithium storage of Si-based anodes.展开更多
The anomalous Hall and Nernst effects provide critical probes for investigating the Berry-curvature-related electronic band characteristics in magnetic materials.In this study,we conducted a comprehensive investigatio...The anomalous Hall and Nernst effects provide critical probes for investigating the Berry-curvature-related electronic band characteristics in magnetic materials.In this study,we conducted a comprehensive investigation into the magnetic,electrical,and thermal transport properties of NdCrGe3single crystals with a Ge-based breathing kagome lattice.This compound undergoes a ferromagnetic transition at 128 K,and magnetic ordering of the Nd sublattice emerges below 100 K.Transport measurements indicate that NdCrGe3manifests large anomalous Hall conductivity withσxyA≈380Ω-1·cm-1at low temperatures and an anomalous Nernst coefficient with|SxyA-max|=0.74µV/K at 100 K.Scaling analysis reveals that NdCrGe3exhibits large intrinsic anomalous Hall conductivity of~260Ω-1·cm-1and falls within the intrinsic regime of the unified model.Furthermore,the anomalous Nernst coefficient breaks down the scaling relationship with magnetization observed in conventional ferromagnets,while the anomalous Nernst conductivity manifests a scaling behavior of T ln T.These results demonstrate that the anomalous transverse transport properties of NdCrGe3are predominantly governed by the intrinsic Berry mechanism.展开更多
Agglomeration supports the high-quality development of the manufacturing industry,and its associated resource and environmental effects play a crucial role in driving green economic development.Based on data from pref...Agglomeration supports the high-quality development of the manufacturing industry,and its associated resource and environmental effects play a crucial role in driving green economic development.Based on data from prefecture-level cities in China from 2005 to 2019,this study employs the inverse distance weighting method,the bivariate local indicator of spatial association model,the spatial Durbin model,and other techniques to explore the relationship between manufacturing agglomeration and PM2.5concentrations,and to assess the impact of its manufacturing agglomeration.Four correlation patterns are observed:high-high,low-low,high-low,and low-high.Among these,high-high and low-low patterns dominate in terms of number of cities.These correlation patterns demonstrate strong temporal stability,with a clear“Matthew effect”.The effect of manufacturing agglomeration on PM2.5levels is significantly negative and helps reduce concentrations regionally,indicating the need to further enhance agglomeration levels regionally.However,it can increase PM2.5levels in neighboring areas due to a siphon effect,and the impact of varies across regions.Compared with levels in 2005-2013,the significance of the relationship between manufacturing agglomeration and PM2.5weakened in the 2013-2019 period.Accordingly,this study proposes countermeasures and policy recommendations aimed at strengthening regional collaborative governance and inspiring differentiated agglomeration strategies to support sustainable economic development in China.展开更多
Understanding the dynamic behavior of fractured rock masses is crucial for ensuring safety and stability in mining,tunneling,and underground construction,particularly where structures are subjected to seismic events o...Understanding the dynamic behavior of fractured rock masses is crucial for ensuring safety and stability in mining,tunneling,and underground construction,particularly where structures are subjected to seismic events or blast-induced vibrations.While previous studies have examined either rate effects or fracture-related influencesseparately,the coupled impact of loading rate and fracture network characteristics remains poorly understood,especially given the stochastic nature of geological discontinuities.This study introduces a novel hybrid framework that combines the bonded particle model(BPM),the discrete fracture network(DFN)and physics-inspired machine learning(PIML)to investigate these complex interactions.The framework uniquely integrates stochastic fracture generation,dynamic numerical simulation,and machine learning to capture both deterministic and probabilistic aspects of rock mass behavior.Results reveal distinct competing mechanisms between rate-strengthening and fractureweakening effects.Dynamic strength exhibits a positive correlation with loading rate while weakening as fracture intensity increases,with a critical fracture intensity range(5-10 m/m2)where strength variability peaks.A significantfindingis the transition in failure modes from predominantly shear failure along pre-existing fractures to mixed tensile-shear failure as fracture intensity and loading rate increase.The developed PIML-based model achieves 97.43% accuracy in predicting dynamic uniaxial compressive strength,while uncertainty quantificationdemonstrates that loading rate and fracture intensity independently contribute 31.17% and 34.71% to strength variation,respectively.These findings provide quantitative guidance for engineering design,enabling more accurate assessment of rock mass stability under dynamic loading conditions and the optimal design of support system based on fracture characteristics.展开更多
In this study,the influences of the thermoelastic effect and fluid viscosity-temperature effect(VTE)on hydraulic fracture growth in deep reservoirs were investigated.A computational model that integrates the thermopor...In this study,the influences of the thermoelastic effect and fluid viscosity-temperature effect(VTE)on hydraulic fracture growth in deep reservoirs were investigated.A computational model that integrates the thermoporoelastic effect and VTE was developed on the basis of the displacement discontinuity method(DDM).The temperature distribution within fractures is determined using a first-order upwind scheme.Using this simulator,this study systematically evaluated the impacts of the poroelastic stress,thermoelastic stress,and VTE of the fracturing fluid on fracture propagation.Furthermore,the dominant controlling factors were identified in both the viscosity-and toughness-dominated regimes.The results show that(1)the thermoelastic stress exhibits behavior opposite to that of poroelastic stress,reducing the injection pressure and increasing the fracture width.(2)Under viscosity-dominated conditions,the influence of the VTE is more remarkable,whereas the thermoelastic effect on fracture propagation is relatively weak.Under toughness-dominated conditions,the influence of the thermoelastic effect on fracture propagation remains relatively weak,and the VTE can essentially be disregarded.(3)When proppant transport is considered,for small proppant particles,the transport distance increases from 88 m to 100 m when the VTE is considered because the VTE increases the fracture length.For large proppant particles,owing to the decrease in viscosity with increasing temperature,the proppant transport distance is significantly reduced from 86 m to 70 m.These results indicate that reasonably selecting the proppant size and paying more attention to the VTE of the fracturing fluid in deep reservoir fracturing are crucial.展开更多
Rechargeable Zn/Sn-air batteries have received considerable attention as promising energy storage devices.However,the electrochemical performance of these batteries is significantly constrained by the sluggish electro...Rechargeable Zn/Sn-air batteries have received considerable attention as promising energy storage devices.However,the electrochemical performance of these batteries is significantly constrained by the sluggish electrocatalytic reaction kinetics at the cathode.The integration of light energy into Zn/Sn-air batteries is a promising strategy for enhancing their performance.However,the photothermal and photoelectric effects generate heat in the battery under prolonged solar irradiation,leading to air cathode instability.This paper presents the first design and synthesis of Ni2-1,5-diamino-4,8-dihydroxyanthraquinone(Ni2DDA),an electronically conductiveπ-d conjugated metal-organic framework(MOF).Ni2DDA exhibits both photoelectric and photothermal effects,with an optical band gap of~1.14 eV.Under illumination,Ni2DDA achieves excellent oxygen evolution reaction performance(with an overpotential of 245 mV vs.reversible hydrogen electrode at 10 mA cm−2)and photothermal stability.These properties result from the synergy between the photoelectric and photothermal effects of Ni2DDA.Upon integration into Zn/Sn-air batteries,Ni2DDA ensures excellent cycling stability under light and exhibits remarkable performance in high-temperature environments up to 80℃.This study experimentally confirms the stable operation of photo-assisted Zn/Sn-air batteries under high-temperature conditions for the first time and provides novel insights into the application of electronically conductive MOFs in photoelectrocatalysis and photothermal catalysis.展开更多
This study offers a comprehensive analysis of the rejuvenation and memory effects observed during temperature cycling in five-component Weeks-Chandler-Andersen(WCA)systems,utilizing molecular dynamics simulations.We i...This study offers a comprehensive analysis of the rejuvenation and memory effects observed during temperature cycling in five-component Weeks-Chandler-Andersen(WCA)systems,utilizing molecular dynamics simulations.We investigate the molecular mechanisms driving these effects from a free volume perspective.Our findings reveal that dynamical processes and structural evolution at varying temperatures operate independently across multiple spatiotemporal scales,thereby highlighting a distinct decoupling of multiscale dynamics within glassy systems.Notably,while the total free volume remains constant over time,a pronounced peak in large free volume is observed during the second stage of temperature cycling.This peak is intricately linked to the aggregation of free volume,a key factor facilitating rejuvenation dynamics.Furthermore,our analysis shows that free volume aggregation primarily occurs in localized regions,which corresponds to the activation of secondary potential wells within the energy landscape.Critically,this process develops independently of large-scale structural changes,thus preserving the system’s memory effects.By emphasizing the crucial role of free volume in the emergence of marginally stable phases and rejuvenation phenomena,this study advances the theoretical understanding of non-equilibrium dynamics and provides valuable molecular insights into the complex physical behaviors inherent to glassy states.展开更多
Heavy metal pollution is becoming increasingly severe,and rare earth elements(REEs)play a crucial role in influencing the environmental impact of heavy metals.Mixed heavy metal pollution presents a significant challen...Heavy metal pollution is becoming increasingly severe,and rare earth elements(REEs)play a crucial role in influencing the environmental impact of heavy metals.Mixed heavy metal pollution presents a significant challenge due to its complex effects.While many studies have focused on single heavy metal pollution,relatively few have examined the pollution caused by rare earth-heavy metal composites.This study investigated the toxic effects of Ce-Zn compound pollution on maize roots and used the integrated biomarker response(IBR)to assess the toxicity of different concentrations of Ce-Zn compound pollution on maize roots.The results showed that Ce-Zn compound pollution had a threshold effect:promoting maize growth at low concentrations but inhibiting growth at a threshold concentration of Ce 50 mg/kg-Zn 50 mg/kg.Ce-Zn compound pollution-induced oxidative stress in maize.When the pollution concentration exceeded the threshold,the H2O2content in maize roots increased by 3.30 and 3.56 times,respectively,compared to the CK group,while the O2-content increased by 1.45 and1.48 times,respectively.Cell structure damage was observed,and the levels of antioxidant enzymes—peroxidase(POD),catalase(CAT),and superoxide dismutase(SOD)—in maize roots gradually increased.At low concentrations,the Ca2+absorption rate in maize roots increased by 82.99%compared to CK.By regulating the Ca2+concentration,the absorption of H+and other ions was affected,enhancing intracellular enzyme activity and improving the tolerance of maize roots to compound pollution.These findings enhance our understanding of the harmful effects of combined pollution from rare earth metals and heavy metals on plants.展开更多
基金supported by the GDAS’Project of Science and Technology Development(No.2022GDASZH-2022010104-2)Guangdong Major Project of Basic and Applied Basic Research(No.2023B0303000006).
摘要Understanding Cd contamination in the soil-rice ecosystem and the underlying its threshold and interaction effects is crucial for controlling Cd pollution and ensuring food safety.Although the quantitative relationships between Cd and environmental variables have been extensively studied,the threshold and interaction effects of multi-source environmental variables remain largely unexplored.This study employs a combination of random forest analysis and a human health risk model to investigate the effects of variables on Cd levels in rice grains,with the goal of quantifying their contributions and elucidating their relationships.The results indicated that the 15 selected variables collectively explained 47.36%of the variation in Cd content,with the top three variables being soil pH,distance from industrial park,and soil Zn.The majority of variables exhibited threshold effects on Cd levels in rice grains.By visualizing the interaction between Soil pH,distance from industrial park,and soil Zn with Cd levels in rice,we demonstrate the threshold effects of them on Cd level in rice grains,thereby providing further insight into the variation observed.Furthermore,oral intake of rice has been identified as the primary route of human exposure,significantly contributing to overall exposure pathways.Understanding these interactions is crucial for gaining insights into the underlying processes driving Cd pollution and fostering sustainable development within the industry.Our findings underscore the crucial need to consider multiple environmental variables and their interactions when managing heavy metals(HMs)contamination and mitigating health risks.
基金financially supported by the National Natural Science Foundation of China(No.12202207)the Natural Science Foundation of Jiangsu Province(No.BK20220968)+1 种基金the Liaoning Re-vitalization Talent Program(No.XLYC2202021)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX_0147).
摘要This study synthesized a high-strength Zr42Ti15Nb20Ta20Al3(at.%)refractory high-entropy alloy(RHEA)via vacuum induction melting.The mechanical behavior of the Zr42Ti15Nb_(2 n)Ta_(2 n)Al3RHEA was systematically investigated through a universal testing machine and split Hopkinson pressure bar system at strain rates up to 5100 s−1,and the temperature change is from 193 K to 673 K.By integrating theoretical derivation and microstructural characterization,we examined the mechanical behavior and deformation mechanisms of the Zr42Ti15Nb_(2 n)Ta_(2 n)Al3RHEA under the synergistic effects of temperature and strain rate.The results demonstrate that the Zr42Ti15Nb_(2 n)Ta_(2 n)Al3RHEA exhibits a significant positive strain rate effect.The dominant deformation mechanism changes with increasing strain rate:cross-slip→localized shear→adiabatic shear.When the strain rate reaches 5100 s−1,the yield strength increases from 1151 MPa to 2112 MPa,and an adiabatic shear band forms.Simultaneously,the microstructure undergoes severe localized deformation,dominated by shear bands,and dynamic recrystallization(DRX)is activated to counteract the deformation.At 193 K,the yield strength is 2241 MPa.Kink bands have appeared,enhancing the ductility of RHEA:the yield strength and the temperature sensitivity coefficient decrease with increasing temperature.However,as the temperature increases,atomic mobility is enhanced,which promotes grain boundary sliding and migration,activating DRX,and effectively mitigating shear localization.This study deepens our understanding of the mechanical properties and deformation mechanisms of the Zr42Ti15Nb20Ta20Al3RHEA.It reveals the microstructure evolution process of the alloy under different strain rates,the synergistic effect of strain rate and temperature,and the influence of strain rate and temperature on the deformation mechanisms of the material.This research lays a theoretical foundation for applying the Zr42Ti15Nb20Ta20Al3RHEA in extreme environments.
基金National Natural Science Foundation of China,No.42471455,No.42230113National Key Research and Development Program of China,No.2022YFC3800804-01。
摘要Ensuring national food security amidst rapid population growth and increasing extreme weather events remains a critical global challenge.However,the extent to which agricultural modernization in China enhances grain yield and contributes to food security remains unclear.Therefore,using panel data from 327 Chinese cities(2013–2021),this study employs spatial econometric models to analyze the spatial spillover effects of agricultural modernization level(AML)on grain yield and to reveal regional heterogeneity across nine major agricultural zones.The results showed a cumulative grain yield increase of 23.7 million tons,with peak productivity concentrated along the Hu Line and declining eastward and westward.AML also exhibited a steady increase but a clear spatial gradient,decreasing from coastal to inland regions,with the highest level observed in Southern China(SC).A key finding was that a 1%increase in AML directly raised local grain yield by an average of 4.185%,accompanied by significant positive spillover effects on neighboring regions.Regional variations revealed distinct patterns:the direct effects of AML were more pronounced in southern and eastern zones,while spillover effects dominated in northern and western zones.The largest positive direct impact of AML on grain yield was observed in the SC(8.499%),while Middle-Lower Yangtze Plain ranked second but exhibited the strongest positive spatial spillover effect(4.534%).These findings highlight the critical role of agricultural modernization in promoting grain production and provide a solid basis for optimizing regional agricultural systems,ensuring food security,and advancing sustainable agriculture.
基金supported by the Excellent Youth Project of Hunan Provincial Department of Education(Grant No.22B0266)。
摘要This research provides analytical solutions to assess the bending-torsional vibration behavior of a thin-walled box girder subjected to moving random loads.The governing equations of a thin-walled box girder have been formulated to incorporate the impact of shear effect.The technique of integral transformation and the method of statistical analysis are employed to determine the average and standard deviation of the displacements at mid-span.The research’s findings are compared with the results from the Newmark-βtechnique and the Monte Carlo method to validate the effectiveness of the proposed strategy.By analysing the parameters,it is confirmed that neglecting the shear effect can result in substantial underestimation of lateral displacement.Compared to the Euler-Bernoulli beam theory,which does not consider the shear effect,the proposed theory shows differences of up to 109%in the average value and 213%in the standard deviation.These analysis results provide a reference for the vibration analysis of thin-walled box girders.
基金supported by National Natural Science Foundation of China(Nos.22172151 and 22372154)。
摘要Understanding the effects of the electric double layer(EDL)on electrode kinetics is of great importance for improving the performance of electrochemical devices.In this work,by using the HER at Au(111)in x M HClO4+(1-x)M NaClO4or NaOH as a model reaction,the intrinsic kinetic parameters for HER has been unveiled based on the modified Poisson-Nernst-Planck equations and the Frumkin-Butler-Volmer theory.Our analysis reveals that i)the EDL effects induced changes in proton concentration cH+RPand electric potential φRPat the reaction plane are the main reason for the difference of HER current in the cases with x M HClO4and x M HClO4+(1-x)M NaClO4;ii)the EDL effects are the main origin for the difference in HER current between acidic and alkaline solutions at the Au(111).Our work demonstrates that microkinetic simulation with properly considering the EDL effects is important for unravelling intrinsic reaction kinetics of electrocatalytic reactions.
基金the financial support for the Article Processing Charge(APC)provided by the Unit of Research,Innovation,and Community Engagement,Faculty of Engineering,Universitas Indonesia(FTUI)Contract Year 2026。
摘要Biomimicry provides a design framework that emulates biological characteristics to exploit their functional advantages.This study presents a biomimetic-based aerodynamic assessment of wing-in-ground(WiG)configurations inspired by flying animals,including birds and mammals,using computational fluid dynamics(CFD).Three biomimetic wing models were developed by translating biological characteristics—such as body size,wing geometry,and flight behavior—into engineering design parameters relevant to near-surface flight.Numerical simulations were performed to evaluate lift,drag,lift-to-drag ratio,and trim stability under various operating conditions.The results demonstrate that each biomimetic configuration exhibits distinct aerodynamic performance consistent with its biological inspiration.The brown pelican-inspired model achieved the highest lift force,reaching approximately 68 kN,reflecting its natural adaptation for efficient lift generation near the surface.In contrast,the sugar glider-inspired model produced the lowest lift,approximately 37 kN,corresponding to its lightweight gliding characteristics.Overall,the findings confirm that biomimicry provides a rational and effective framework for preliminary WiG craft design,enabling aerodynamic performance to be systematically tailored through biologically inspired geometrical adaptations.
基金financially supported by the Natural Science Foundation of Shandong Province (No.ZR2022QE076)the National Natural Science Foundation of China (No.52202092)the Science and Technology Support Plan for Youth Innovation of Colleges and Universities of Shandong Province of China (No.2023KJ104)。
摘要Electrochemical CO2 reduction reaction(CO2RR) into valuable formate provides a strategy for carbon neutrality.Bismuth(Bi) catalysts,attributed to their appropriate energy barrier of OCHO*intermediate,have demonstrated substantial potential for the advancement of electrocatalytic CO2 reduction to formate.However,due to the weak bonding of protons(H*) of Bi,the available protonate of CO2 on Bi is insufficient,which limits the formation of OCHO*.Prediction by theoretical calculation,chlorine doping can effectively promote the dissociation of H2O and thus achieve effective proton supply.We prepare chlorine-doped Bi(Cl-Bi) via an electrochemical conversion strategy for electroreduction of CO2 .An obvious improvement of faradaic efficiency(FE) of formate(96.7% at-0.95 V vs.RHE) can be achieved on Cl-Bi,higher than that of Bi(89.4%).Meanwhile,Cl-Bi has the highest formate production rate of 275 μmol h-1cm-2at-0.95 V vs.RHE,which is 1.2 times higher than that of Bi(224 μmol h-1cm-2).In situ characterizations and kinetic analysis reveal that chlorine doping promotes the activation of H2O and supply sufficient protons to promote the protonation of CO2 to OCHO*,which is consistent with theoretical calculation.The study presents an effective strategy for rational design of highly efficient electrocatalysts to promote green chemical production.
基金National Natural Science Foundation of China,No.42471202,No.72441005。
摘要Existing studies on the Regional Comprehensive Economic Partnership(RCEP)mainly focused on institutional features,macro-economic impacts,and trade-network structures,while its geographic attributes and their implications remain underexplored.Taking the RCEP as a case,this paper examines how the FTA reshapes China’s trade geography and validates these effects with an enhanced GTAP model,providing an empirical basis for advancing trade-geography theory.Key findings include:(1)RCEP significantly reduces regional trade costs.After full implementation of the agreement,the average tariffs among member countries will decrease to 40.5%of the pre-implementation level,while import and export trade facilitation levels improve by 34.3%and 29.6%,respectively.However,these improvements exhibit marked regional disparities.(2)RCEP asymmetrically promotes China’s foreign trade growth,with stronger import stimulation than export expansion,alongside significant product-specific variations.(3)The agreement reshapes China’s trade geography,driving a 7.66%increase in intra-RCEP trade while reducing extra-RCEP trade by 0.80%.(4)The restructuring of China’s trade patterns under RCEP emerges from the complex interplay of trade creation,diversion,and crowding-out effects.Accordingly,China should further harmonize regional tariff schedules,enhance trade-facilitation mechanisms,strengthen industrial competitiveness and expand multilateral partnerships.
基金the financial support from the National Natural Science Foundation of China(Grant No.42041006)the Fundamental Research Funds for the Central Universities,CHD(Grant Nos.300102265718,300102264902).
摘要This study integrates unconfined compression tests with high-resolution computed tomography(CT)to analyze the pore heterogeneity,crack propagation,and failure modes of red sandstone specimens with diameters ranging from 10 mm to 100 mm.Key findings include:(1)With increasing specimen size,crack initiation stress(CI),damage stress(CD),and unconfined compressive strength(UCS)initially increase and then decrease;(2)In smaller specimens,stress concentration due to pore heterogeneity leads to splitting failure and lower strength;(3)In medium-sized specimens,friction dominates crack propagation,causing shear failure,while increased fragment rotation enhances energy dissipation,yielding highest strength;(4)In larger specimens,cracks tend to propagate along bedding planes,reducing energy dissipation and then weakening strength.These results provide insights into the reverse size effect on sandstone strength and have implications for engineering applications.
基金supported by the National Science and Tech-nology Major Project of China(Nos.2017-II-0007-0021 and J2019-II-0017-0038)。
摘要Aerodynamic performances of axial compressors are significantly affected by variation of Reynolds number in aero-engines.In the design and analysis of compressors,previous correction methods for cascades and stages have difficulties in predicting comprehensively Reynolds number effects on airfoils,matching and characteristics curves.This study proposes Re-correction models for loss,deviation angle and endwall blockage based on classical theories and cascade tests,and loss and deviation models show good agreement in test data of NACA65 and C4 cascades.Throughflow method considering Reynolds number effects is developed by integrating the correction models into a verified Streamline Curvature(SLC)tool.A three-stage axial compressor is investigated through SLC and CFD methods from design Reynolds number(Red=2106)to low Re=4104,and the numerical methods are validated with test data of characteristic curves and spanwise distributions at Red.With Re reduction,SLC method with correction models well predicts variation in overall performances compared with CFD calculations and Wassell's model.Streamwise and spanwise matching such as total pressure and loss distributions in SLC predictions are basically consistent with those in CFD results at near-stall points under design and low Reynolds numbers.SLC and CFD methods share similar detections of stall risks in the third stage(Stg3),and their analyses of diffusion processes deviate to some extent due to different predictions in separated endwall flow.The correction models can be adopted to consider Reynolds number effects in through-flow design and analysis of axial compressors.
摘要Dryland biodiversity–productivity relationships remain poorly resolved.Specifically,the environmental conditions governing the shift between complementarity and mass ratio mechanisms remain unclear,limiting the effectiveness of restoration and management strategies.To address this gap,the aim of this study was to investigate the geographical patterns of diversity and biomass production in herbaceous communities along a 2100-km precipitation gradient in North China.We studied howα-andβ-diversity affect community-wide productivity using linear mixed-effects models and piecewise structural equation models,along with rolling-window change-point analyses.In arid regions,biomass productivity was primarily driven by interspecificniche complementarity,where higher functional diversity(FD(α))enhanced resource-use efficiency.However,in semi-arid regions,productivity was regulated by the mass ratio effect,specificallythrough the traits of dominant species,including community weighted mean height and specificleaf area,as these species exploited broader resource spectra with increasing water availability.A critical mechanistic shift occurred at a mean annual precipitation(MAP)threshold of~168 mm(95%CI:152–171 mm;p<0.001).Below this threshold,productivity was driven by diversity-mediated complementarity and stress tolerant strategies.Conversely,as MAP surpassed 168 mm,the system transitioned to mass ratio control,coincident with a shift toward competitive strategies.Overall,our study provides empirical evidence to guide dryland management:prioritising the maintenance of functional diversity in arid communities,while emphasising dominant-trait optimisation(plant height and specificleaf area)in semi-arid communities to maximise aboveground biomass.
基金Project supported by the Clean Hydrogen Partnership and its members within the HyLICAL project(grant number 101101461)the Research Council of Norway within LIQUID-H project(grant number 336403)+3 种基金Agencia Estatal de Investigación(AEI/10.13039/501100011033)(grant numbers PID2019-105720RB-100,PID2020-115704RB-C33,PID2023-146047OB-I00)US Air Force Office of Scientific Research(grant FA8655-21-1-7044)co-financed by EU,Ministerio de Hacienda y Función Pública,FEDER and Junta de Andalucía(project PPIT2024-31833)ⅦPlan Propio de Investigación from University of Seville
摘要Gas liquefiers allow efficient transport and storage of gases,key for the development of new energy vectors such as hydrogen fuel.In this sense,magnetic liquefiers based on the magnetocaloric effect are an energy-saving and sustainable alternative to current systems based on the Joule-Thomson expansion.Here,we report the magnetocaloric effect of light rare-earth-based Ce(La)In2 alloys near the hydrogen condensation point.They exhibit a first-order ferromagnetic to paramagnetic phase transition with reduced thermal hysteresis(0.05 K) and moderate criticality compared to their heavy rare-earth-based counterparts.Both isothermal entropy change,and adiabatic entropy change have been indirectly determined from heat capacity measurements.A previously developed method based on lowtemperature truncation of heat capacity data was applied for those calculations,accounting for ~8%underestimation of the maximum values as well as possible misinterpretations of the results in the paramagnetic range.The parent CeIn2 alloy shows an isothermal entropy change of 9.5 J/(kg·K) and an adiabatic temperature change of 2.8 K for a magnetic field change of 5 T.The substitution of Ce by La leads to a slight decrease of the transition temperature in the explored range together with a significant reduction of the magnetocaloric magnitudes:about-1.0 J/(kg·K) and about 0.2 K per atom fraction of La for the isothermal entropy and adiabatic temperature changes for 5 T,respectively.
摘要Silicon dioxide(SiO)is regarded as a promising anode candidate for high-energy-density lithium-ion batteries(LIBs)owing to its superior theoretical specific capacity.However,SiO anodes encounter substantial challenges,including substantial volume expansion and persistent growth of a thick solid electrolyte interphase(SEI).In this work,a composite conductive network with dual pinning and piezoelectric effects is proposed,which is cleverly designed to improve the electrochemical reaction kinetics of the electrode.Within the proposed network architecture,single-walled carbon nanotubes(CNTs)serve as fast electronic conductors and structural protective layers,forming a three-dimensional(3D)coating network on the surface of SiO particles.Barium titanate(BTO)nanoparticles are anchored at the nodes of the CNT network through the formation of rigid anchor points,dispersing stress throughout the network.Concurrently,mechanical stress induced by electrochemical reactions prompts BTO to generate a local electric field,facilitating Li+transport.Consequently,the developed anode(SiO@PCB)demonstrates remarkable electrochemical performance in LIBs,exhibiting a capacity retention rate of 94%even after 500 cycles at 1 A g-1.Furthermore,a capacity retention of 71.6%is demonstrated by SiO@PCB anode after 1000 cycles at 5 C in sulfide-based all-solid-state LIBs using an NCM83 cathode.This composite conductive network structure provides an effective guidance plan for achieving interface stability and long-term lithium storage of Si-based anodes.
基金supported by the National Key R&D Program of China(Grant No.2024YFA1409200)the National Natural Science Foundation of China(Grant Nos.12595332 and 11974394)+2 种基金the Chinese Academy of Sciences(CAS)Project for Young Scientists in Basic Research(Grant No.YSBR-057)the Synergetic Extreme Condition User Facility(SECUF)the Scientific Instrument Developing Project of CAS(Grant No.ZDKYYQ20210003)。
摘要The anomalous Hall and Nernst effects provide critical probes for investigating the Berry-curvature-related electronic band characteristics in magnetic materials.In this study,we conducted a comprehensive investigation into the magnetic,electrical,and thermal transport properties of NdCrGe3single crystals with a Ge-based breathing kagome lattice.This compound undergoes a ferromagnetic transition at 128 K,and magnetic ordering of the Nd sublattice emerges below 100 K.Transport measurements indicate that NdCrGe3manifests large anomalous Hall conductivity withσxyA≈380Ω-1·cm-1at low temperatures and an anomalous Nernst coefficient with|SxyA-max|=0.74µV/K at 100 K.Scaling analysis reveals that NdCrGe3exhibits large intrinsic anomalous Hall conductivity of~260Ω-1·cm-1and falls within the intrinsic regime of the unified model.Furthermore,the anomalous Nernst coefficient breaks down the scaling relationship with magnetization observed in conventional ferromagnets,while the anomalous Nernst conductivity manifests a scaling behavior of T ln T.These results demonstrate that the anomalous transverse transport properties of NdCrGe3are predominantly governed by the intrinsic Berry mechanism.
基金supported by the National Natural Science Foundation of China“Research on the Multi-scale Regional Industrial Spatial Evolution Mechanism,Resource and Environmental Effects,and Green Transformation in the Yellow River Basin”[Grant No.42371194]Taishan Scholar Foundation of Shandong Province[Grant Nos.tsqn202408148 and tstp20240821].
摘要Agglomeration supports the high-quality development of the manufacturing industry,and its associated resource and environmental effects play a crucial role in driving green economic development.Based on data from prefecture-level cities in China from 2005 to 2019,this study employs the inverse distance weighting method,the bivariate local indicator of spatial association model,the spatial Durbin model,and other techniques to explore the relationship between manufacturing agglomeration and PM2.5concentrations,and to assess the impact of its manufacturing agglomeration.Four correlation patterns are observed:high-high,low-low,high-low,and low-high.Among these,high-high and low-low patterns dominate in terms of number of cities.These correlation patterns demonstrate strong temporal stability,with a clear“Matthew effect”.The effect of manufacturing agglomeration on PM2.5levels is significantly negative and helps reduce concentrations regionally,indicating the need to further enhance agglomeration levels regionally.However,it can increase PM2.5levels in neighboring areas due to a siphon effect,and the impact of varies across regions.Compared with levels in 2005-2013,the significance of the relationship between manufacturing agglomeration and PM2.5weakened in the 2013-2019 period.Accordingly,this study proposes countermeasures and policy recommendations aimed at strengthening regional collaborative governance and inspiring differentiated agglomeration strategies to support sustainable economic development in China.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52304091,52374095)the Shenzhen Science and Technology Program(Grant No.JCYJ20220531102012028).
摘要Understanding the dynamic behavior of fractured rock masses is crucial for ensuring safety and stability in mining,tunneling,and underground construction,particularly where structures are subjected to seismic events or blast-induced vibrations.While previous studies have examined either rate effects or fracture-related influencesseparately,the coupled impact of loading rate and fracture network characteristics remains poorly understood,especially given the stochastic nature of geological discontinuities.This study introduces a novel hybrid framework that combines the bonded particle model(BPM),the discrete fracture network(DFN)and physics-inspired machine learning(PIML)to investigate these complex interactions.The framework uniquely integrates stochastic fracture generation,dynamic numerical simulation,and machine learning to capture both deterministic and probabilistic aspects of rock mass behavior.Results reveal distinct competing mechanisms between rate-strengthening and fractureweakening effects.Dynamic strength exhibits a positive correlation with loading rate while weakening as fracture intensity increases,with a critical fracture intensity range(5-10 m/m2)where strength variability peaks.A significantfindingis the transition in failure modes from predominantly shear failure along pre-existing fractures to mixed tensile-shear failure as fracture intensity and loading rate increase.The developed PIML-based model achieves 97.43% accuracy in predicting dynamic uniaxial compressive strength,while uncertainty quantificationdemonstrates that loading rate and fracture intensity independently contribute 31.17% and 34.71% to strength variation,respectively.These findings provide quantitative guidance for engineering design,enabling more accurate assessment of rock mass stability under dynamic loading conditions and the optimal design of support system based on fracture characteristics.
基金financial support of the Basic Science Center Project of the National Natural Science Foundation of China(Grant No.52288101)“Flow Control of Ultra-deep and Extra-deep Oil and Gas Drilling and Production”.
摘要In this study,the influences of the thermoelastic effect and fluid viscosity-temperature effect(VTE)on hydraulic fracture growth in deep reservoirs were investigated.A computational model that integrates the thermoporoelastic effect and VTE was developed on the basis of the displacement discontinuity method(DDM).The temperature distribution within fractures is determined using a first-order upwind scheme.Using this simulator,this study systematically evaluated the impacts of the poroelastic stress,thermoelastic stress,and VTE of the fracturing fluid on fracture propagation.Furthermore,the dominant controlling factors were identified in both the viscosity-and toughness-dominated regimes.The results show that(1)the thermoelastic stress exhibits behavior opposite to that of poroelastic stress,reducing the injection pressure and increasing the fracture width.(2)Under viscosity-dominated conditions,the influence of the VTE is more remarkable,whereas the thermoelastic effect on fracture propagation is relatively weak.Under toughness-dominated conditions,the influence of the thermoelastic effect on fracture propagation remains relatively weak,and the VTE can essentially be disregarded.(3)When proppant transport is considered,for small proppant particles,the transport distance increases from 88 m to 100 m when the VTE is considered because the VTE increases the fracture length.For large proppant particles,owing to the decrease in viscosity with increasing temperature,the proppant transport distance is significantly reduced from 86 m to 70 m.These results indicate that reasonably selecting the proppant size and paying more attention to the VTE of the fracturing fluid in deep reservoir fracturing are crucial.
基金supported by the National Natural Science Foundation of China(No.62464010)Spring City Plan-Special Program for Young Talents(K202005007)+2 种基金Yunnan Talents Support Plan for Young Talents(XDYC-QNRC-2022-0482)Yunnan Local Colleges Applied Basic Research Projects(202101BA070001-138)Frontier Research Team of Kunming University 2023.
摘要Rechargeable Zn/Sn-air batteries have received considerable attention as promising energy storage devices.However,the electrochemical performance of these batteries is significantly constrained by the sluggish electrocatalytic reaction kinetics at the cathode.The integration of light energy into Zn/Sn-air batteries is a promising strategy for enhancing their performance.However,the photothermal and photoelectric effects generate heat in the battery under prolonged solar irradiation,leading to air cathode instability.This paper presents the first design and synthesis of Ni2-1,5-diamino-4,8-dihydroxyanthraquinone(Ni2DDA),an electronically conductiveπ-d conjugated metal-organic framework(MOF).Ni2DDA exhibits both photoelectric and photothermal effects,with an optical band gap of~1.14 eV.Under illumination,Ni2DDA achieves excellent oxygen evolution reaction performance(with an overpotential of 245 mV vs.reversible hydrogen electrode at 10 mA cm−2)and photothermal stability.These properties result from the synergy between the photoelectric and photothermal effects of Ni2DDA.Upon integration into Zn/Sn-air batteries,Ni2DDA ensures excellent cycling stability under light and exhibits remarkable performance in high-temperature environments up to 80℃.This study experimentally confirms the stable operation of photo-assisted Zn/Sn-air batteries under high-temperature conditions for the first time and provides novel insights into the application of electronically conductive MOFs in photoelectrocatalysis and photothermal catalysis.
基金supported by the National Natural Science Foundation of China(No.22341304)the National Key R&D Program of China(Nos.2020YFA0713601 and 2023YFA1008800)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0180303)。
摘要This study offers a comprehensive analysis of the rejuvenation and memory effects observed during temperature cycling in five-component Weeks-Chandler-Andersen(WCA)systems,utilizing molecular dynamics simulations.We investigate the molecular mechanisms driving these effects from a free volume perspective.Our findings reveal that dynamical processes and structural evolution at varying temperatures operate independently across multiple spatiotemporal scales,thereby highlighting a distinct decoupling of multiscale dynamics within glassy systems.Notably,while the total free volume remains constant over time,a pronounced peak in large free volume is observed during the second stage of temperature cycling.This peak is intricately linked to the aggregation of free volume,a key factor facilitating rejuvenation dynamics.Furthermore,our analysis shows that free volume aggregation primarily occurs in localized regions,which corresponds to the activation of secondary potential wells within the energy landscape.Critically,this process develops independently of large-scale structural changes,thus preserving the system’s memory effects.By emphasizing the crucial role of free volume in the emergence of marginally stable phases and rejuvenation phenomena,this study advances the theoretical understanding of non-equilibrium dynamics and provides valuable molecular insights into the complex physical behaviors inherent to glassy states.
基金supported by the Joint Funds of the National Natural Science Foundation of China(No.U21A20238)the Natural Science Foundation of Heilongjiang Province(No.LH2021D002)Heilongjiang Provincial Key Laboratory of Soil Protection and Remediation。
摘要Heavy metal pollution is becoming increasingly severe,and rare earth elements(REEs)play a crucial role in influencing the environmental impact of heavy metals.Mixed heavy metal pollution presents a significant challenge due to its complex effects.While many studies have focused on single heavy metal pollution,relatively few have examined the pollution caused by rare earth-heavy metal composites.This study investigated the toxic effects of Ce-Zn compound pollution on maize roots and used the integrated biomarker response(IBR)to assess the toxicity of different concentrations of Ce-Zn compound pollution on maize roots.The results showed that Ce-Zn compound pollution had a threshold effect:promoting maize growth at low concentrations but inhibiting growth at a threshold concentration of Ce 50 mg/kg-Zn 50 mg/kg.Ce-Zn compound pollution-induced oxidative stress in maize.When the pollution concentration exceeded the threshold,the H2O2content in maize roots increased by 3.30 and 3.56 times,respectively,compared to the CK group,while the O2-content increased by 1.45 and1.48 times,respectively.Cell structure damage was observed,and the levels of antioxidant enzymes—peroxidase(POD),catalase(CAT),and superoxide dismutase(SOD)—in maize roots gradually increased.At low concentrations,the Ca2+absorption rate in maize roots increased by 82.99%compared to CK.By regulating the Ca2+concentration,the absorption of H+and other ions was affected,enhancing intracellular enzyme activity and improving the tolerance of maize roots to compound pollution.These findings enhance our understanding of the harmful effects of combined pollution from rare earth metals and heavy metals on plants.