The finite volume method （FVM） and the lattice Boltzmann method （LBM） are coupled with each other to construct a new cross-scaling method to deal with the porous flow problem. To check the effectiveness of our dev...The finite volume method （FVM） and the lattice Boltzmann method （LBM） are coupled with each other to construct a new cross-scaling method to deal with the porous flow problem. To check the effectiveness of our developed cross-scaling LBM-FVM, the above mentioned problem is also solved by the well known LBM-LBM. Based on the data checking of the published data and the results of LBM-FVM and LBM-LBM, good agreement is observed.展开更多
This case study examines how the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project, a whole-of-government and whole-of-community approach to planning for and adapting to...This case study examines how the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project, a whole-of-government and whole-of-community approach to planning for and adapting to sea level rise, addressed coastal resilience in a southeastern Virginia watershed that spans multiple jurisdictions. Meeting the challenge of sea level rise requires that actors across multiple sectors—citizens, community organizations, industry and government—understand the risks and work together to make critical decisions regarding adaptation strategies and actions. The case study area includes Little Creek Amphibious Base, which is bordered by the cities of Norfolk and Virginia Beach. Adaptation responses to sea level rise by the military base and the local governments will impact each other and the residents of the area, but no cooperative agreements are in place for a joint or collaborative response. This case study examines public and private infrastructure at risk, the infrastructure interdependencies, and mechanisms for providing collaborative solutions. Engagement of area residents and other stakeholders is also integral to the process of adaptation, which includes educating about sea level rise risk and provides a mechanism for social learning that enables stakeholders to participate in critical adaptation decisions. The case study demonstrates a method to improve resiliency in the case study area and inform a regional, multi-sectoral response to sea level rise adaptation strategies.展开更多
Flexoelectricity,an electromechanical coupling between strain gradient and electrical polarization in dielectrics or semiconductors,has attracted significant scientific interest.It is reported that large flexoelectric...Flexoelectricity,an electromechanical coupling between strain gradient and electrical polarization in dielectrics or semiconductors,has attracted significant scientific interest.It is reported that large flexoelectric behaviors can be obtained at the nanoscale because of the size effect.However,the flexoelectric responses of centrosymmetric semiconductors(CSs)are extremely weak under a conventional beam-bending approach,owing to weak flexoelectric coefficients and small strain gradients.The flexoelectric-like effect is an enhanced electromechanical effect coupling the flexoelectricity and piezoelectricity.In this paper,a composite structure consisting of piezoelectric dielectric layers and a CS layer is proposed.The electromechanical response of the CS is significantly enhanced via antisymmetric piezoelectric polarization.Consequently,the cross-scale mechanically tuned carrier distribution in the semiconductor is realized.Meanwhile,the significant size dependence of the electromechanical fields in the semiconductor is demonstrated.The flexoelectronics suppression is found when the semiconductor thickness reaches a critical size(0.8μm).In addition,the first-order carrier density of the composite structure under local loads is illustrated.Our results can suggest the structural design for flexoelectric semiconductor devices.展开更多
Current spatio-temporal action detection methods lack sufficient capabilities in extracting and comprehending spatio-temporal information. This paper introduces an end-to-end Adaptive Cross-Scale Fusion Encoder-Decode...Current spatio-temporal action detection methods lack sufficient capabilities in extracting and comprehending spatio-temporal information. This paper introduces an end-to-end Adaptive Cross-Scale Fusion Encoder-Decoder (ACSF-ED) network to predict the action and locate the object efficiently. In the Adaptive Cross-Scale Fusion Spatio-Temporal Encoder (ACSF ST-Encoder), the Asymptotic Cross-scale Feature-fusion Module (ACCFM) is designed to address the issue of information degradation caused by the propagation of high-level semantic information, thereby extracting high-quality multi-scale features to provide superior features for subsequent spatio-temporal information modeling. Within the Shared-Head Decoder structure, a shared classification and regression detection head is constructed. A multi-constraint loss function composed of one-to-one, one-to-many, and contrastive denoising losses is designed to address the problem of insufficient constraint force in predicting results with traditional methods. This loss function enhances the accuracy of model classification predictions and improves the proximity of regression position predictions to ground truth objects. The proposed method model is evaluated on the popular dataset UCF101-24 and JHMDB-21. Experimental results demonstrate that the proposed method achieves an accuracy of 81.52% on the Frame-mAP metric, surpassing current existing methods.展开更多
Safe and just operating spaces(SJOS)are influenced by complex cross-scale interactions and cascading effects spanning global,regional,and local landscape scales.However,existing SJOS research has often focused on sing...Safe and just operating spaces(SJOS)are influenced by complex cross-scale interactions and cascading effects spanning global,regional,and local landscape scales.However,existing SJOS research has often focused on single-scale assessments,overlooking the impacts of multiscale interactions and within-region heterogeneity on urban SJOS.To address this gap,we developed a cross-scale framework for assessing urban SJOS,explicitly incorporating top-down influences from upper-level constraints and bottom-up effects from lower-level heterogeneity.This approach was applied to China's five major metropolises to examine the states and cross-scale dynamics influencing urban SJOS between 1990 and 2020.Our findings reveal that the SJOS of China's metropolises were primarily influenced by factors at national and local landscape scales,with weaker influences from the global and continental scales.A persistent trade-off between social justice and environmental safety was identified across spatiotemporal scales.For instance,Chongqing in southwestern China lagged behind the eastern four metropolises in social performance but exhibited stronger environmental safety due to its extensive natural landscapes,which mitigated the anthropogenic impacts of urban centers.Regional issues,such as the overshoot of PM_(2.5)and ecological footprints(EF),were primarily driven by the bottom-up accumulation of localized pressures,while the overshoot of CO_(2)was attributed to national policy constraints and the universal exceedance of safe thresholds across scales.Addressing urban sustainability requires avoiding adverse cascading effects from other levels by emphasizing landscape heterogeneity within metropolises and fostering coordinated collaboration across scales,particularly at the regional landscape and national levels.展开更多
In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through top...In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.展开更多
This paper analyzed the pore structure, quantified the pore fractal dimension, calculated the grading index(GI) of mixed aggregate, and studied the relationship among GI, pore structure, and strength to describe the c...This paper analyzed the pore structure, quantified the pore fractal dimension, calculated the grading index(GI) of mixed aggregate, and studied the relationship among GI, pore structure, and strength to describe the cross-scale characteristics of backfill, which is made from stone powder and cemented tailing. A series of experiments were conducted on stone powder cement tailings backfill(SPCTB). The GI formulas for mixed aggregates, containing stone powder and tailings, were derived based on the Füller theory. The nuclear magnetic resonance(NMR) fractal dimensions of backfills were derived using fractal geometry principles. Compared to the mesopore and macropore fractal dimensions, the correlation between micropore fractal dimension and macro-properties in terms of NMR porosity, pore structure complexity, uniaxial compression strength(UCS), and GI is the most significant. Macropore fractal dimension is generally correlated with UCS and GI and the other properties such as the shape of mixed aggregates also have an impact on fractal dimension. However, mesopore fractal dimension has no obvious relationship with macro-properties. Finally, the relationship between GI and UCS was studied, which contributed to improving backfill’s strength and optimizing gradation.展开更多
A simultaneous prediction of macroscopic deformation and microstructure evolution is critical for un-derstanding the deformation mechanism of components.In this work,the hydro-bulging process of 2219 aluminum alloy sh...A simultaneous prediction of macroscopic deformation and microstructure evolution is critical for un-derstanding the deformation mechanism of components.In this work,the hydro-bulging process of 2219 aluminum alloy sheet was investigated using cross-scale numerical modeling,in which the macroscopic finite element method(FEM)and crystal plasticity finite element method(CPFEM)were combined.The calculated texture evolution exhibits good agreement with the experimental results,and the stress er-ror between the two scales is generally small.The effects of different strain states on texture evolution and slip mode are further discussed.As the strain ratioηincreases,the volume fractions of the initial Rotated Copper texture component andγ-Fiber texture component decrease significantly,which tend to be stabilized at P texture component.The initial Rotated Cube texture component is inclined to rotate towards the Cube texture component,while the volume fraction of this orientation is relatively stable.The lower strain ratio can considerably enhance the activity of more equivalent slip systems,promoting a more uniform strain distribution over grains.The difficulty of grain deformation changes as the lat-tice rotates.The grain with easy-to-deform orientation can gradually rotate to a stable orientation during plastic deformation,which has a lower Schmid factor.展开更多
In order to further study the reliability of macro evaluation indexes,molecular dynamics (MD) was applied to the evaluation of asphalt binder.Micro evaluation indexes (potential energy,surface free energy,solubility p...In order to further study the reliability of macro evaluation indexes,molecular dynamics (MD) was applied to the evaluation of asphalt binder.Micro evaluation indexes (potential energy,surface free energy,solubility parameter and diffusion coefficient) of asphalt binder in different service phases (virgin,modified,aged and rejuvenated) were simulated.Combined with the variation characteristics of asphalt binder macro evaluation indexes (permeability,ductility,viscosity and softening point) in different service phases,the cross-scale correlation of macro-micro evaluation indexes was explored.The results show that the macro and micro evaluation indexes of asphalt binder have different characteristics in different service phases.The essence of the variation in the properties of asphalt binders is the difference in micro composition.In addition,there is a certain correlation between macro and micro evaluation indexes,which can be described by the gray relation theory.The cross-scale correlation of macro-micro evaluation indexes can provide a certain theoretical basis for the development of asphalt binder.展开更多
Global and local modeling is essential for image super-resolution tasks.However,current efforts often lack explicit consideration of the cross-scale knowledge in large-scale earth observation scenarios,resulting in su...Global and local modeling is essential for image super-resolution tasks.However,current efforts often lack explicit consideration of the cross-scale knowledge in large-scale earth observation scenarios,resulting in suboptimal single-scale representations in global and local modeling.The key motivation of this work is inspired by two observations:1)There exists hierarchical features at the local and global regions in remote sensing images,and 2)they exhibit scale variation of similar ground objects(e.g.cross-scale similarity).In light of these,this paper presents an effective method to grasp the global and local image hierarchies by systematically exploring the cross-scale correlation.Specifically,we developed a Cross-scale Self-Attention(CSA)to model the global features,which introduces an auxiliary token space to calculate cross-scale self-attention matrices,thus exploring global dependency from diverse token scales.To extract the cross-scale localities,a Cross-scale Channel Attention(CCA)is devised,where multi-scale features are explored and progressively incorporated into an enriched feature.Moreover,by hierarchically deploying CSA and CCA into transformer groups,the proposed Cross-scale Hierarchical Transformer(CHT)can effectively explore cross-scale representations in remote sensing images,leading to a favorable reconstruction performance.Comprehensive experiments and analysis on four remote sensing datasets have demonstrated the superiority of CHT in both simulated and real-world remote sensing scenes.In particular,our CHT outperforms the state-of-the-art approach(TransENet)in terms of PSNR by 0.11 dB on average,but only accounts for 54.8%of its parameters.展开更多
This study mainly investigates the influence of pore water characteristics on the adsorption properties of coalbed methane through integrated low field nuclear magnetic resonance(LF-NMR),adsorption experiments,and mol...This study mainly investigates the influence of pore water characteristics on the adsorption properties of coalbed methane through integrated low field nuclear magnetic resonance(LF-NMR),adsorption experiments,and molecular dynamics(MD)simulations.Pore water states in three coal ranks were characterized during progressive hydration.Multi-scale analysis revealed how pore water evolution regulates methane adsorption processes.During the diffusion-dominated stage(M2-M3),adsorbed water penetrates into the micropores.In the highly wettable brown coal(L1),the adsorbed water content reaches 2.12 g while in the anthracite(A1),it is only 0.29 g.During the active water injection stage(M4-M6),non-adsorbed water dominates in anthracite(over 85%of the total water content of 4.01 g),while adsorbed water remains dominant in lignite(over 60%of the total water content of 3.52 g).Water content plays a key role in methane adsorption in coal.During the water addition phase,the influence of methane adsorption on medium-to-low-rank coal is relatively weak,while the methane adsorption capacity of high-rank coal A1 shows a significant decrease during both the water diffusion and water addition phases,corresponding to a reduction in Langmuir volume of 21.22 cm^(3)/g.Molecular dynamics(MD)results further show that the free energy between molecules on the surface of hydroxyl-modified coal increases,with hydroxyl groups driving electrostatic interactions between coal and water molecules.Increased steric hindrance inhibits hydrogen bond formation and reduces the rate of hydrogen bond growth.There is a significant correlation between pore water content and coal-water molecular interaction energy,which cross-scale validates the results of LF-NMR testing and MD simulations.展开更多
In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalabilit...In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalability through modular design.However,traditional manufacturing processes are limited by mold dependence,organic solvent toxicity,and insufficient molding capability for complex structures,resulting in difficulty achieving precise regulation of cross-scale pores.Additive manufacturing(AM)technology employs a digital layered molding strategy to achieve the cross-scale structural regulation of catalysts from macroscopic flow channels to mesopores and micropores.This paper summarizes recent advances in the structural design of monolithic catalysts enabled by AM technologies and highlights their emerging applications in catalytic processes.Structurally,AM-fabricated monoliths have been effectively employed in key chemical reactions such as fuel reforming,CO_(2)conversion,biofuel synthesis.Strategies such as geometrical topology optimization,multi-scale pore synergy,biomimetic structural design,and functional gradient integration have been utilized to enhance heat and mass transport,reduce pressure drops,and improve overall catalytic performance.By overcoming the limitations of traditional catalysts,AM technologies create a new paradigm for addressing the longstanding challenge of coupling mass transfer with reaction kinetics.This approach provides a feasible pathway for driving both theoretical innovation and practical implementation of high-efficiency catalytic systems.展开更多
The measurement field of view of the conventional transmission electron microscopy(TEM)nano-moiréand scanning transmission electron microscopy(STEM)nano-moirémethods is limited to the hundred-nanometer scale...The measurement field of view of the conventional transmission electron microscopy(TEM)nano-moiréand scanning transmission electron microscopy(STEM)nano-moirémethods is limited to the hundred-nanometer scale,unable to meet the deformation field measurement requirements of micrometer-scale materials such as transistors and micro-devices.This paper proposed a novel measurement method based on scanning secondary moire,which can realize cross-scale deformation field measurement from nanometers to micrometers and solve the problem of insufficient measurement accuracy when using only the TEM moire method.This method utilized the electron wave in the TEM passing through the atomic lattice of two layers of different materials to generate TEM moire.On this basis,the TEM was tuned to the STEM mode,and by adjusting parameters such as the amount of defocusing,magnification,scanning angle,etc.,the electron beam was focused on the position near the interface of the two layers of materials,and at the same time,the scanning line was made approximately parallel to the direction of one of the TEM moire fringes.The scanning secondary moire patterns were generated when the scanning spacing was close to the TEM moire spacing.Through this method,the deformation field,mechanical properties,and internal defects of crystals can be detected by a large field of view with high sensitivity and high efficiency.Compared to traditional methods,the advantages of scanning secondary moire method lie in significantly improving the measurement field of TEM moire and STEM moire methods,realizing the cross-scale visualization measurement from nanometers to micrometers,and possessing atomic-level displacement measurement sensitivity.It can also simplify and efficiently identify dislocations,offering a new method for large-area visualization observation of dislocation density in broad application prospects.展开更多
Multi-photon three-dimensional(3D)nanoprinting technology,renowned for its 3D processing capability and nano-scale resolution beyond the diffraction limit,has garnered significant attention in the micro/nano-additive ...Multi-photon three-dimensional(3D)nanoprinting technology,renowned for its 3D processing capability and nano-scale resolution beyond the diffraction limit,has garnered significant attention in the micro/nano-additive manufacturing field.This technology finds widespread applications in optics,biology,and mechanical engineering research.However,its broader adoption in industrial production and applications has been hindered by limitations such as relatively slow processing speed and restricted material formability and functionality.This paper presents the latest advancements in multi-photon 3D nanoprinting,with a focus on analyzing optical methods to enhance the processing speed of scanning and projection techniques.Additionally,it examines issues related to the formability and functionality of commonly used photosensitive materials,including organic polymers,inorganic compounds,and composite materials.In conclusion,this paper offers a comprehensive summary from the perspectives of productivity,cost,materials,and cross-scale processing,along with proposed routes and future directions.展开更多
In electrochemical energy storage systems,the sodium-ion battery is typically integrated in the form of a“cell-module-cluster”,but its cross-scale thermal runaway triggering risk and the propagation mechanism remain...In electrochemical energy storage systems,the sodium-ion battery is typically integrated in the form of a“cell-module-cluster”,but its cross-scale thermal runaway triggering risk and the propagation mechanism remain unclear.This study reveals the cross-scale thermal runaway triggering and propagation behavior of sodium-ion batteries of“cell-module-cluster”under overcharge conditions,and investigates the effects of key factors,including module spacing,triggering cell location,and heat dissipation condition,on the thermal runaway propagation behavior.Results demonstrate that the thermal runaway propagation in a module containing the overcharged cell follows a sequential triggering mode,while thermal runaway in the downstream module exhibits a simultaneous triggering mode with greater severity.Furthermore,increasing the module spacing or enhancing the heat dissipation capacity can effectively reduce the heat accumulation and prevent the trigger of thermal runaway.On the above basis,the multi-dimensional evaluation strategy is proposed to quantitatively assess the hazard of sodium-ion battery cluster thermal runaway.The findings serve as a foundation for the safe design of sodium-ion batteries in energy storage systems.展开更多
The clastic sedimentary realm comprises a number of genetically distinct depositional systems, which are dominated by distinct depositional processes. A variogram and a Levy-stable probability distribution-based geost...The clastic sedimentary realm comprises a number of genetically distinct depositional systems, which are dominated by distinct depositional processes. A variogram and a Levy-stable probability distribution-based geostatistical method have been applied to analyze petrophysical properties from well logs and cores from a variety of depositional environments in sedimentary basins from Australia to quantify the heterogeneity and upscaling range of different depositional systems. Two reservoir sequences with contrasting sedimentary facies, depositional processes and a diagenetic history are investigated for their petrographic, petrophysical and log characters and their scaling behaviour. The microscopic derived petrophysical parameters, including visual porosity, grain size, sorting and amount of matrix, core plug measured porosity and permeability and log-derived V-shale, porosity and permeability, have been found to be well correlated (|R|=0.72 to 0.91) across all the scales for the reservoir sequence deposited under a single predominant depositional process and a gradational change of the energy regime (Bilyara-1). In contrast, for the reservoir sequence (East Swan-2), which was deposited in heterogeneous processes and underwent diagenetic alteration, the cross-correlation of the petrophysical properties derived from the three different scales is extremely poor (|R|=0.01-0.54). Log-derived porosity and permeability for a thinly bedded reservoir sequence with an individual bed thinner than one metre can therefore be affected by the intrinsic averaging effects of the logging tools.展开更多
The urban morphological system,developed over multiple phases,exhibits complex cross-scale characteristics,with significant scale disc repancies among morphological elements at the same hierarchical level,which sugges...The urban morphological system,developed over multiple phases,exhibits complex cross-scale characteristics,with significant scale disc repancies among morphological elements at the same hierarchical level,which suggests that the cross-scale sliding model holds the potential to reveal additional characteristics of urban morphology.This paper introduces a multifractal method that integrates Spacematrix morphological classification for the analysis of detailed urban building data within defined boundaries.Using the Nanjing Old City in China as a case study,the results reveal a dense yet balanced urban form,showing annular differentiation characterized by fragmented fringe belts at the macro level and a uniform mixture of diverse land use types and building types at the micro level.The typical scale invariance and multifractality are not consistently observed across single-type analyses.The study identifies height uniformization and spaciousness differentiation in the scaling of urban morphology,attributing the multifractal mechanism to the interweaving and transformation of multiple types across scales.This enhanced multifractal approach improves spatial mapping capabilities,aiding in the elucidation of the formation mechanisms of urban morphology.展开更多
Comprehensive Summary The design of cross-scale morphological structures has emerged as a fundamental strategy to tune electromagnetic response behaviors.However,challenges remain in precisely regulating the morpholog...Comprehensive Summary The design of cross-scale morphological structures has emerged as a fundamental strategy to tune electromagnetic response behaviors.However,challenges remain in precisely regulating the morphological structures of absorbers.Herein,the VN@hierarchical porous carbon/cobalt@carbon nanotubes composites were synthesized through sol-gel self-propagation method.展开更多
In this study,to investigate the mechanism through which high-voltage electrical pulses(HVEPs)enhance coal permeability and improve coalbed methane(CBM)extraction efficiency,liquid nitrogen adsorption analysis,nuclear...In this study,to investigate the mechanism through which high-voltage electrical pulses(HVEPs)enhance coal permeability and improve coalbed methane(CBM)extraction efficiency,liquid nitrogen adsorption analysis,nuclear magnetic resonance,infrared spectroscopy,and scanning electron microscopy were performed on HVEPtreated coal samples.The mentioned techniques were used to analyze the crack structures,pore distribution patterns,and changes in the chemical functional groups in the coal samples.The permeability enhancement mechanism of HVEP in coal was explored from macroscopic,mesoscopic,and microscopic perspectives.The chemical modification of coal through the breakdown of its oxygen-containing functional groups reduced the gas adsorption capacity of the coal samples and enhanced their desorption abilities.Simultaneously,the number of pores within the bottleneck pore interval of the coal samples increased significantly.The closed pores transformed into semi-closed and open pores.The pore volume was 2.86 times the pore volume of the original coal,while the pore specific surface area growth rate was 48.67%.This pronounced pore expansion effect eliminated the bottleneck pore interval,which reduced CBM seepage efficiency and enabled cross-scale CBM transport.Extensive parallel fractures and fissures appeared throughout the coal body.The connectivity within the porefracture network was enhanced substantially.This improved connectivity provided efficient pathways for gas transport.展开更多
基金supported by the National Nature Science Foundation of China (10932010,51176172,11072220)the Research Grants Council of the Government of the HKSAR (PolyU5172/02E,PolyU5221/05E)
文摘The finite volume method （FVM） and the lattice Boltzmann method （LBM） are coupled with each other to construct a new cross-scaling method to deal with the porous flow problem. To check the effectiveness of our developed cross-scaling LBM-FVM, the above mentioned problem is also solved by the well known LBM-LBM. Based on the data checking of the published data and the results of LBM-FVM and LBM-LBM, good agreement is observed.
文摘This case study examines how the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project, a whole-of-government and whole-of-community approach to planning for and adapting to sea level rise, addressed coastal resilience in a southeastern Virginia watershed that spans multiple jurisdictions. Meeting the challenge of sea level rise requires that actors across multiple sectors—citizens, community organizations, industry and government—understand the risks and work together to make critical decisions regarding adaptation strategies and actions. The case study area includes Little Creek Amphibious Base, which is bordered by the cities of Norfolk and Virginia Beach. Adaptation responses to sea level rise by the military base and the local governments will impact each other and the residents of the area, but no cooperative agreements are in place for a joint or collaborative response. This case study examines public and private infrastructure at risk, the infrastructure interdependencies, and mechanisms for providing collaborative solutions. Engagement of area residents and other stakeholders is also integral to the process of adaptation, which includes educating about sea level rise risk and provides a mechanism for social learning that enables stakeholders to participate in critical adaptation decisions. The case study demonstrates a method to improve resiliency in the case study area and inform a regional, multi-sectoral response to sea level rise adaptation strategies.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB2011400)the National Natural Science Foundation of China(Grant No.52375081).
文摘Flexoelectricity,an electromechanical coupling between strain gradient and electrical polarization in dielectrics or semiconductors,has attracted significant scientific interest.It is reported that large flexoelectric behaviors can be obtained at the nanoscale because of the size effect.However,the flexoelectric responses of centrosymmetric semiconductors(CSs)are extremely weak under a conventional beam-bending approach,owing to weak flexoelectric coefficients and small strain gradients.The flexoelectric-like effect is an enhanced electromechanical effect coupling the flexoelectricity and piezoelectricity.In this paper,a composite structure consisting of piezoelectric dielectric layers and a CS layer is proposed.The electromechanical response of the CS is significantly enhanced via antisymmetric piezoelectric polarization.Consequently,the cross-scale mechanically tuned carrier distribution in the semiconductor is realized.Meanwhile,the significant size dependence of the electromechanical fields in the semiconductor is demonstrated.The flexoelectronics suppression is found when the semiconductor thickness reaches a critical size(0.8μm).In addition,the first-order carrier density of the composite structure under local loads is illustrated.Our results can suggest the structural design for flexoelectric semiconductor devices.
基金support for this work was supported by Key Lab of Intelligent and Green Flexographic Printing under Grant ZBKT202301.
文摘Current spatio-temporal action detection methods lack sufficient capabilities in extracting and comprehending spatio-temporal information. This paper introduces an end-to-end Adaptive Cross-Scale Fusion Encoder-Decoder (ACSF-ED) network to predict the action and locate the object efficiently. In the Adaptive Cross-Scale Fusion Spatio-Temporal Encoder (ACSF ST-Encoder), the Asymptotic Cross-scale Feature-fusion Module (ACCFM) is designed to address the issue of information degradation caused by the propagation of high-level semantic information, thereby extracting high-quality multi-scale features to provide superior features for subsequent spatio-temporal information modeling. Within the Shared-Head Decoder structure, a shared classification and regression detection head is constructed. A multi-constraint loss function composed of one-to-one, one-to-many, and contrastive denoising losses is designed to address the problem of insufficient constraint force in predicting results with traditional methods. This loss function enhances the accuracy of model classification predictions and improves the proximity of regression position predictions to ground truth objects. The proposed method model is evaluated on the popular dataset UCF101-24 and JHMDB-21. Experimental results demonstrate that the proposed method achieves an accuracy of 81.52% on the Frame-mAP metric, surpassing current existing methods.
基金supported by the National Natural Science Foundation of China(Grant No.42101296)the Natural Science Foundation of Chongqing(Grant No.CSTB2023NSCQ-MSX0041)Chongqing Municipal Training Program of Innovation and Entrepreneurship Project(Grants No.S202410635155 and X202410635116)。
文摘Safe and just operating spaces(SJOS)are influenced by complex cross-scale interactions and cascading effects spanning global,regional,and local landscape scales.However,existing SJOS research has often focused on single-scale assessments,overlooking the impacts of multiscale interactions and within-region heterogeneity on urban SJOS.To address this gap,we developed a cross-scale framework for assessing urban SJOS,explicitly incorporating top-down influences from upper-level constraints and bottom-up effects from lower-level heterogeneity.This approach was applied to China's five major metropolises to examine the states and cross-scale dynamics influencing urban SJOS between 1990 and 2020.Our findings reveal that the SJOS of China's metropolises were primarily influenced by factors at national and local landscape scales,with weaker influences from the global and continental scales.A persistent trade-off between social justice and environmental safety was identified across spatiotemporal scales.For instance,Chongqing in southwestern China lagged behind the eastern four metropolises in social performance but exhibited stronger environmental safety due to its extensive natural landscapes,which mitigated the anthropogenic impacts of urban centers.Regional issues,such as the overshoot of PM_(2.5)and ecological footprints(EF),were primarily driven by the bottom-up accumulation of localized pressures,while the overshoot of CO_(2)was attributed to national policy constraints and the universal exceedance of safe thresholds across scales.Addressing urban sustainability requires avoiding adverse cascading effects from other levels by emphasizing landscape heterogeneity within metropolises and fostering coordinated collaboration across scales,particularly at the regional landscape and national levels.
基金National Natural Science Foundation Council of China(Grant No.52305359)Hubei Provincial Natural Science Foundation of China(Grant No.2023AFB141)National Medical Products Administration Key Laboratory for Dental Materials(PKUSS20240401)。
文摘In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.
基金Project(41672298)supported by the National Natural Science Foundation of ChinaProject(2017YFC0602901)supported by the National Key Research and Development Program of China。
文摘This paper analyzed the pore structure, quantified the pore fractal dimension, calculated the grading index(GI) of mixed aggregate, and studied the relationship among GI, pore structure, and strength to describe the cross-scale characteristics of backfill, which is made from stone powder and cemented tailing. A series of experiments were conducted on stone powder cement tailings backfill(SPCTB). The GI formulas for mixed aggregates, containing stone powder and tailings, were derived based on the Füller theory. The nuclear magnetic resonance(NMR) fractal dimensions of backfills were derived using fractal geometry principles. Compared to the mesopore and macropore fractal dimensions, the correlation between micropore fractal dimension and macro-properties in terms of NMR porosity, pore structure complexity, uniaxial compression strength(UCS), and GI is the most significant. Macropore fractal dimension is generally correlated with UCS and GI and the other properties such as the shape of mixed aggregates also have an impact on fractal dimension. However, mesopore fractal dimension has no obvious relationship with macro-properties. Finally, the relationship between GI and UCS was studied, which contributed to improving backfill’s strength and optimizing gradation.
基金financially supported by the National Natural Science Foundation of China(No.52275322)the Heilongjiang Touyan Team(No.HITTY-20190015).
文摘A simultaneous prediction of macroscopic deformation and microstructure evolution is critical for un-derstanding the deformation mechanism of components.In this work,the hydro-bulging process of 2219 aluminum alloy sheet was investigated using cross-scale numerical modeling,in which the macroscopic finite element method(FEM)and crystal plasticity finite element method(CPFEM)were combined.The calculated texture evolution exhibits good agreement with the experimental results,and the stress er-ror between the two scales is generally small.The effects of different strain states on texture evolution and slip mode are further discussed.As the strain ratioηincreases,the volume fractions of the initial Rotated Copper texture component andγ-Fiber texture component decrease significantly,which tend to be stabilized at P texture component.The initial Rotated Cube texture component is inclined to rotate towards the Cube texture component,while the volume fraction of this orientation is relatively stable.The lower strain ratio can considerably enhance the activity of more equivalent slip systems,promoting a more uniform strain distribution over grains.The difficulty of grain deformation changes as the lat-tice rotates.The grain with easy-to-deform orientation can gradually rotate to a stable orientation during plastic deformation,which has a lower Schmid factor.
基金Funded by the Fundamental Research Funds for the Central Universities (No. 2572021AW10)。
文摘In order to further study the reliability of macro evaluation indexes,molecular dynamics (MD) was applied to the evaluation of asphalt binder.Micro evaluation indexes (potential energy,surface free energy,solubility parameter and diffusion coefficient) of asphalt binder in different service phases (virgin,modified,aged and rejuvenated) were simulated.Combined with the variation characteristics of asphalt binder macro evaluation indexes (permeability,ductility,viscosity and softening point) in different service phases,the cross-scale correlation of macro-micro evaluation indexes was explored.The results show that the macro and micro evaluation indexes of asphalt binder have different characteristics in different service phases.The essence of the variation in the properties of asphalt binders is the difference in micro composition.In addition,there is a certain correlation between macro and micro evaluation indexes,which can be described by the gray relation theory.The cross-scale correlation of macro-micro evaluation indexes can provide a certain theoretical basis for the development of asphalt binder.
基金supported in part by the National Natural Science Foundation of China[grant numbers 42230108,and 61971319].
文摘Global and local modeling is essential for image super-resolution tasks.However,current efforts often lack explicit consideration of the cross-scale knowledge in large-scale earth observation scenarios,resulting in suboptimal single-scale representations in global and local modeling.The key motivation of this work is inspired by two observations:1)There exists hierarchical features at the local and global regions in remote sensing images,and 2)they exhibit scale variation of similar ground objects(e.g.cross-scale similarity).In light of these,this paper presents an effective method to grasp the global and local image hierarchies by systematically exploring the cross-scale correlation.Specifically,we developed a Cross-scale Self-Attention(CSA)to model the global features,which introduces an auxiliary token space to calculate cross-scale self-attention matrices,thus exploring global dependency from diverse token scales.To extract the cross-scale localities,a Cross-scale Channel Attention(CCA)is devised,where multi-scale features are explored and progressively incorporated into an enriched feature.Moreover,by hierarchically deploying CSA and CCA into transformer groups,the proposed Cross-scale Hierarchical Transformer(CHT)can effectively explore cross-scale representations in remote sensing images,leading to a favorable reconstruction performance.Comprehensive experiments and analysis on four remote sensing datasets have demonstrated the superiority of CHT in both simulated and real-world remote sensing scenes.In particular,our CHT outperforms the state-of-the-art approach(TransENet)in terms of PSNR by 0.11 dB on average,but only accounts for 54.8%of its parameters.
基金supported by the National Science Fund for Distinguished Young Scholars(No.51925404)the National Natural Science Foundation of China(Nos.52104233,52104228 and 52404261)the Fundamental Research Funds for the Central Universities(No.2023ZDPY05).
文摘This study mainly investigates the influence of pore water characteristics on the adsorption properties of coalbed methane through integrated low field nuclear magnetic resonance(LF-NMR),adsorption experiments,and molecular dynamics(MD)simulations.Pore water states in three coal ranks were characterized during progressive hydration.Multi-scale analysis revealed how pore water evolution regulates methane adsorption processes.During the diffusion-dominated stage(M2-M3),adsorbed water penetrates into the micropores.In the highly wettable brown coal(L1),the adsorbed water content reaches 2.12 g while in the anthracite(A1),it is only 0.29 g.During the active water injection stage(M4-M6),non-adsorbed water dominates in anthracite(over 85%of the total water content of 4.01 g),while adsorbed water remains dominant in lignite(over 60%of the total water content of 3.52 g).Water content plays a key role in methane adsorption in coal.During the water addition phase,the influence of methane adsorption on medium-to-low-rank coal is relatively weak,while the methane adsorption capacity of high-rank coal A1 shows a significant decrease during both the water diffusion and water addition phases,corresponding to a reduction in Langmuir volume of 21.22 cm^(3)/g.Molecular dynamics(MD)results further show that the free energy between molecules on the surface of hydroxyl-modified coal increases,with hydroxyl groups driving electrostatic interactions between coal and water molecules.Increased steric hindrance inhibits hydrogen bond formation and reduces the rate of hydrogen bond growth.There is a significant correlation between pore water content and coal-water molecular interaction energy,which cross-scale validates the results of LF-NMR testing and MD simulations.
基金supported by the National Natural Science Foundation of China(Grant No.52405414)the China Postdoctoral Science Foundation(Grant No.2024M762580)+1 种基金Young Talent Fund of Xi'an Association for Science and Technology(Grant No.0959202513033)the Youth Innovation Team of Shaanxi Universities,and the Fundamental Research Funds for Central Universities.The authors gratefully acknowledge the support by the Instrumental Analysis Center of Xi’an Jiaotong University for sample characterization.
文摘In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalability through modular design.However,traditional manufacturing processes are limited by mold dependence,organic solvent toxicity,and insufficient molding capability for complex structures,resulting in difficulty achieving precise regulation of cross-scale pores.Additive manufacturing(AM)technology employs a digital layered molding strategy to achieve the cross-scale structural regulation of catalysts from macroscopic flow channels to mesopores and micropores.This paper summarizes recent advances in the structural design of monolithic catalysts enabled by AM technologies and highlights their emerging applications in catalytic processes.Structurally,AM-fabricated monoliths have been effectively employed in key chemical reactions such as fuel reforming,CO_(2)conversion,biofuel synthesis.Strategies such as geometrical topology optimization,multi-scale pore synergy,biomimetic structural design,and functional gradient integration have been utilized to enhance heat and mass transport,reduce pressure drops,and improve overall catalytic performance.By overcoming the limitations of traditional catalysts,AM technologies create a new paradigm for addressing the longstanding challenge of coupling mass transfer with reaction kinetics.This approach provides a feasible pathway for driving both theoretical innovation and practical implementation of high-efficiency catalytic systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.12372178 and 12327801).
文摘The measurement field of view of the conventional transmission electron microscopy(TEM)nano-moiréand scanning transmission electron microscopy(STEM)nano-moirémethods is limited to the hundred-nanometer scale,unable to meet the deformation field measurement requirements of micrometer-scale materials such as transistors and micro-devices.This paper proposed a novel measurement method based on scanning secondary moire,which can realize cross-scale deformation field measurement from nanometers to micrometers and solve the problem of insufficient measurement accuracy when using only the TEM moire method.This method utilized the electron wave in the TEM passing through the atomic lattice of two layers of different materials to generate TEM moire.On this basis,the TEM was tuned to the STEM mode,and by adjusting parameters such as the amount of defocusing,magnification,scanning angle,etc.,the electron beam was focused on the position near the interface of the two layers of materials,and at the same time,the scanning line was made approximately parallel to the direction of one of the TEM moire fringes.The scanning secondary moire patterns were generated when the scanning spacing was close to the TEM moire spacing.Through this method,the deformation field,mechanical properties,and internal defects of crystals can be detected by a large field of view with high sensitivity and high efficiency.Compared to traditional methods,the advantages of scanning secondary moire method lie in significantly improving the measurement field of TEM moire and STEM moire methods,realizing the cross-scale visualization measurement from nanometers to micrometers,and possessing atomic-level displacement measurement sensitivity.It can also simplify and efficiently identify dislocations,offering a new method for large-area visualization observation of dislocation density in broad application prospects.
基金financially supported by the National Key Research and Development Program of China(2021YFF0502700)the National Natural Science Foundation of China(52275429 and 62205117)+4 种基金the Innovation Project of Optics Valley Laboratory(OVL2021ZD002)the Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)the West Light Foundation of the Chinese Academy of Sciences(xbzg-zdsys-202206)the Knowledge Innovation Program of Wuhan-Shuguangthe Hubei Provincial Natu-ral Science Foundation of China(2022CFB792).
文摘Multi-photon three-dimensional(3D)nanoprinting technology,renowned for its 3D processing capability and nano-scale resolution beyond the diffraction limit,has garnered significant attention in the micro/nano-additive manufacturing field.This technology finds widespread applications in optics,biology,and mechanical engineering research.However,its broader adoption in industrial production and applications has been hindered by limitations such as relatively slow processing speed and restricted material formability and functionality.This paper presents the latest advancements in multi-photon 3D nanoprinting,with a focus on analyzing optical methods to enhance the processing speed of scanning and projection techniques.Additionally,it examines issues related to the formability and functionality of commonly used photosensitive materials,including organic polymers,inorganic compounds,and composite materials.In conclusion,this paper offers a comprehensive summary from the perspectives of productivity,cost,materials,and cross-scale processing,along with proposed routes and future directions.
基金supported by the Anhui Quality Infrastructure Standardization Project(Grant No.2024MKSO7)the Science and Technology Project of State Grid(SGAHDK00DJJS2310027)the Anhui Provincial Natural Science Foundation(Grant No.2208085UD03).
文摘In electrochemical energy storage systems,the sodium-ion battery is typically integrated in the form of a“cell-module-cluster”,but its cross-scale thermal runaway triggering risk and the propagation mechanism remain unclear.This study reveals the cross-scale thermal runaway triggering and propagation behavior of sodium-ion batteries of“cell-module-cluster”under overcharge conditions,and investigates the effects of key factors,including module spacing,triggering cell location,and heat dissipation condition,on the thermal runaway propagation behavior.Results demonstrate that the thermal runaway propagation in a module containing the overcharged cell follows a sequential triggering mode,while thermal runaway in the downstream module exhibits a simultaneous triggering mode with greater severity.Furthermore,increasing the module spacing or enhancing the heat dissipation capacity can effectively reduce the heat accumulation and prevent the trigger of thermal runaway.On the above basis,the multi-dimensional evaluation strategy is proposed to quantitatively assess the hazard of sodium-ion battery cluster thermal runaway.The findings serve as a foundation for the safe design of sodium-ion batteries in energy storage systems.
基金with the financial support of the key laboratory of petroleum accumulation mechanism of the Education Minstry University of Petroleum (Beijing)China
文摘The clastic sedimentary realm comprises a number of genetically distinct depositional systems, which are dominated by distinct depositional processes. A variogram and a Levy-stable probability distribution-based geostatistical method have been applied to analyze petrophysical properties from well logs and cores from a variety of depositional environments in sedimentary basins from Australia to quantify the heterogeneity and upscaling range of different depositional systems. Two reservoir sequences with contrasting sedimentary facies, depositional processes and a diagenetic history are investigated for their petrographic, petrophysical and log characters and their scaling behaviour. The microscopic derived petrophysical parameters, including visual porosity, grain size, sorting and amount of matrix, core plug measured porosity and permeability and log-derived V-shale, porosity and permeability, have been found to be well correlated (|R|=0.72 to 0.91) across all the scales for the reservoir sequence deposited under a single predominant depositional process and a gradational change of the energy regime (Bilyara-1). In contrast, for the reservoir sequence (East Swan-2), which was deposited in heterogeneous processes and underwent diagenetic alteration, the cross-correlation of the petrophysical properties derived from the three different scales is extremely poor (|R|=0.01-0.54). Log-derived porosity and permeability for a thinly bedded reservoir sequence with an individual bed thinner than one metre can therefore be affected by the intrinsic averaging effects of the logging tools.
基金supported by Jiangsu Provincial Department of Science and Technology(Grant No.BE2023799)the National Natural Science Foundation of China(Grant No.52308051)。
文摘The urban morphological system,developed over multiple phases,exhibits complex cross-scale characteristics,with significant scale disc repancies among morphological elements at the same hierarchical level,which suggests that the cross-scale sliding model holds the potential to reveal additional characteristics of urban morphology.This paper introduces a multifractal method that integrates Spacematrix morphological classification for the analysis of detailed urban building data within defined boundaries.Using the Nanjing Old City in China as a case study,the results reveal a dense yet balanced urban form,showing annular differentiation characterized by fragmented fringe belts at the macro level and a uniform mixture of diverse land use types and building types at the micro level.The typical scale invariance and multifractality are not consistently observed across single-type analyses.The study identifies height uniformization and spaciousness differentiation in the scaling of urban morphology,attributing the multifractal mechanism to the interweaving and transformation of multiple types across scales.This enhanced multifractal approach improves spatial mapping capabilities,aiding in the elucidation of the formation mechanisms of urban morphology.
基金supported by the National Natural Science Foundation of China(Nos.52173267,22066017,51861006)the key laboratory of high temperature electromagnetic materials and structure of MOE(KB202402).
文摘Comprehensive Summary The design of cross-scale morphological structures has emerged as a fundamental strategy to tune electromagnetic response behaviors.However,challenges remain in precisely regulating the morphological structures of absorbers.Herein,the VN@hierarchical porous carbon/cobalt@carbon nanotubes composites were synthesized through sol-gel self-propagation method.
基金supported by the National Key Research and Development Program of China(No.2024YFC3013804)the National Natural Science Foundation of China(No.52274173)the Open Fund of State Key Laboratory of Coal Mine Disaster Dynamics and Control(No.2011DA105287-FW202305)。
文摘In this study,to investigate the mechanism through which high-voltage electrical pulses(HVEPs)enhance coal permeability and improve coalbed methane(CBM)extraction efficiency,liquid nitrogen adsorption analysis,nuclear magnetic resonance,infrared spectroscopy,and scanning electron microscopy were performed on HVEPtreated coal samples.The mentioned techniques were used to analyze the crack structures,pore distribution patterns,and changes in the chemical functional groups in the coal samples.The permeability enhancement mechanism of HVEP in coal was explored from macroscopic,mesoscopic,and microscopic perspectives.The chemical modification of coal through the breakdown of its oxygen-containing functional groups reduced the gas adsorption capacity of the coal samples and enhanced their desorption abilities.Simultaneously,the number of pores within the bottleneck pore interval of the coal samples increased significantly.The closed pores transformed into semi-closed and open pores.The pore volume was 2.86 times the pore volume of the original coal,while the pore specific surface area growth rate was 48.67%.This pronounced pore expansion effect eliminated the bottleneck pore interval,which reduced CBM seepage efficiency and enabled cross-scale CBM transport.Extensive parallel fractures and fissures appeared throughout the coal body.The connectivity within the porefracture network was enhanced substantially.This improved connectivity provided efficient pathways for gas transport.
