Recycling spent lithium-ion(Li+)batteries is critical for achieving environmental conservation and the strategic recovery of essential resources.Compared with conventional methods for recovering cathode materials,whic...Recycling spent lithium-ion(Li+)batteries is critical for achieving environmental conservation and the strategic recovery of essential resources.Compared with conventional methods for recovering cathode materials,which are energy-intensive and prone to secondary pollution,the direct regeneration approach has emerged as a rapid and highly efficient method,gaining widespread attention in recent years.However,this approach faces major challenges,including degraded electrochemical performances and limited economic value.This study,therefore,proposes a high-value direct regeneration strategy to convert degraded spent LiFePO_(4)(S-LFP)into a gradient manganese(Mn)-doped regenerated LiFe_(0.7)Mn_(0.3)PO_(4)/C(R-LFMP)composite.This method leverages the inherent microcracks and Li vacancies present in S-LFP,likely acting as diffusion channels for the Mn^(2+)/Li^(+)ions.Through a two-step mechanochemical ball-milling and carbothermal reduction process,this approach achieves simultaneous Li replenishment and surface-localised Mn gradient doping with enhanced structural control.Notably,the R-LFMP exhibits an exceptional electrochemical performance.At 0.1 C,it delivers a discharge capacity of 161.4 mA h g^(−1)and an energy density of 563.5 Wh kg^(−1)(representing a 60.5%improvement over S-LFP).Additionally,it maintains 83%capacity retention after 900 cycles at 0.5C,a considerable enhancement compared to commercial LFMP(62%).Furthermore,the regenerated cathode material generates a net profit of$7.102 kg^(−1),surpassing the profitability of conventional recycling methods by 90%.Overall,this study introduces a transformative and sustainable LFP regeneration technology,achieving breakthroughs in electrochemical restoration and high-value recycling,while paving the way for the closed-loop utilisation of LFP-based energy storage systems.展开更多
Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with pha...Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with phase gradient modulation can be used to achieve illusion optics,featuring the advantages of simple geometric structure and feasible implementation compared with the well-known transformation optics method.The underlying mechanism is the anomalous diffraction law caused by the phase gradient,which provides a theoretical basis for freely manipulating the propagation path of light.By considering a specific example,we will demonstrate that the phase gradient can transform spatial coordinates in real space into illusion space,thereby converting a plane in real space into a curved surface structure in illusion space to achieve the illusion effect.This approach provides a viable alternative to transformation optics for designing illusion devices.展开更多
β-Ga_(2)O_(3)is a promising candidate for solarblind ultraviolet photodetection owing to its suitable bandgap of approximately 4.9 eV,excellent photoresponse characteristics,and high stability.However,the lack of a s...β-Ga_(2)O_(3)is a promising candidate for solarblind ultraviolet photodetection owing to its suitable bandgap of approximately 4.9 eV,excellent photoresponse characteristics,and high stability.However,the lack of a sufficient driving force within the material leads to extensive bulk charge recombination,limiting its photocurrent and thus posing significant challenges in designing high-performance Ga_(2)O_(3)-based photodetection.In this study,we propose a gradient doping strategy to achieve a Sn-doping concentration gradient along theβ-Ga_(2)O_(3)film thickness.By combining sol-gel synthesis with rapid thermal annealing,a spatially graded band structure with a full-space built-in electric field is constructed,which increases the width of band bending over a large region and is crucial for significantly enhancing carrier separation and transport in the bulk.The resulting gradient Sn-dopedβ-Ga_(2)O_(3)enables exceptional photoelectric performance without an external bias under 254 nm irradiation,including a superior responsivity of 66.88 mA W^(-1),a high detectivity of 8.12×10^(11)Jones,and a fast rise/decay time of 79/65 ms,outstanding most existing similar reported photoelectrochemical(PEC)type optoelectronic devices.Additionally,the device exhibits excellent long-term stability and enables high-resolution underwater ultraviolet imaging.This study demonstrates that the gradient doping strategy provides a feasible approach for enhancing the PEC performance ofβ-Ga_(2)O_(3)photoelectrodes.展开更多
Suffusion refers to the loss of fineparticles within the soil matrix without any associated volume change,induced by hydrodynamic forces.This study investigated the suffusion of sand-clay mixtures through one-dimensio...Suffusion refers to the loss of fineparticles within the soil matrix without any associated volume change,induced by hydrodynamic forces.This study investigated the suffusion of sand-clay mixtures through one-dimensional soil column experiments under a stepwise increase in hydraulic gradient(i),aiming to evaluate the critical hydraulic gradient(icrit)as a function of the size ratio between sand and clay,clay type,and ionic concentration.It was found that icrit was less than 0.1 for all sand-clay mixtures examined in this study.In addition,the lower peak concentrations of filtrated clay observed in sand-illite mixtures,compared to those of sand-kaolinite mixtures at the same level of i,suggest that illite particles are more susceptible to suffusion.Overall,the observed breakthrough curves,mass fraction of filtrated clay,volume of outflow,and total injection time presented in this study highlight the importance of considering clay type,sand-to-clay size ratio,and ionic concentration when assessing the suffusion behavior of clay-containing soils under a stepwise increase in hydraulic gradient.展开更多
Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key fac...Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key factors in anammox bacteria enrichment.This study investigated the mechanisms driving anammox bacteria enrichment in lab-scale simulated CWs treating high-nitrogen wastewater,focusing on bacterial community re-sponses across wetland layers with various strategies,including continuous up-flow influent,nitrogen loading increase,effluent recirculation,intermittent influent,and anammox bacteria inoculation.Results showed that total relative and absolute abundances of anammox bacteria ranged from 0.77%to 12.50%and from 0.13 to 6.46×10^(7) copies/g,respectively.Dissolved oxygen and pH had significant positive correlations with the absolute abundance of anammox bacteria,while organic matter and nitrate negatively impacted their relative abundance.Permutational multivariate analysis of variance indicated that spatial heterogeneity explained more variation in anammox bacteria abundance(43.44%)compared to operational strategies(8.58%).In terms of microbial interactions,60 dominant species exhibited potential correlations with anammox bacteria,comprising 170 interactions(105 positive and 65 negative),which suggested that anammox bacteria generally foster cooperative relationships with dominant bacteria.Notably,significant interspecies interactions were observed between Candidatus Kuenenia(dominant anammox bacteria in CWs)and species within the genera Chitinivibrio-nia and Anaerolineaceae,suggesting that microbial interactions primarily manifest as indirect facilitative effects rather than direct mutualistic relationships.Given that the Normalized Stochasticity Ratio in CWs were<50%,this study inferred that environmental gradients have greater influence on anammox bacteria than microbial interactions.展开更多
The osteochondral(OC)interface exhibits a mineral gradient,varying in thickness by several hundred micrometers across different species.Disruptions in this interface damage OC tissues,leading to osteoarthritis.The nat...The osteochondral(OC)interface exhibits a mineral gradient,varying in thickness by several hundred micrometers across different species.Disruptions in this interface damage OC tissues,leading to osteoarthritis.The natural architecture and composition of native OC interfaces can be replicated using biomaterial scaffolds via regenerative engineering approaches.A novel one-step bioextrusion process was employed to fabricate a unitary synthetic graft(USG),which mimics the native OC interface’s mineral concentration gradient.This novel USG is composed of an agarose-based cartilage layer and a bone layer,consisting of agarose enriched with 20%(200 g/L)hydroxyapatite.The USG features a gradient interface with mineral concentrations transitioning from 0%to 20%(mass fraction),mimicking the transition between the cartilage and bone.Thermogravimetric analysis revealed that the gradient transition lengths of the graft and native OC tissue harvested from bovine knees were similar((647±21)vs.(633±124)μm).The linear viscoelastic properties of the grafts,which were evaluated using strain sweep and frequency sweep tests with oscillatory shear,indicated a dominant storage modulus over loss modulus similar to that of native OC tissues.The compressive and stress relaxation behaviors of the USGs demonstrated that the graft maintained structural integrity under mechanical stress.Viability assays performed after bioextrusion showed that chondrocytes and human fetal osteoblast cells successfully integrated and survived within their designated regions of the graft.The novel USGs exhibit properties similar to native OC tissue and are promising candidates for regenerating OC defects and restoring knee joint functionality.展开更多
The S38C railway axle undergoes induction hardening,resulting in a gradient-distributed microstructure and mechanical properties.The accurate identification of gradient-distributed plastic parameters for the S38C axle...The S38C railway axle undergoes induction hardening,resulting in a gradient-distributed microstructure and mechanical properties.The accurate identification of gradient-distributed plastic parameters for the S38C axle remains a challenging task.To tackle this challenge,the present study proposes a novel approach for identifying the gradient-distributed plastic parameters for the S38C axle by integrating nano-indentation techniques with the machine learning method.Firstly,nano-indentation tests are conducted along the radial direction of the S38C axle to obtain the gradient-distributed load-displacement curves,nano-hardness,and elastic modulus.Subsequently,the dimensionless analysis is performed to obtain the representative stress,strain,and yield stress from load-displacement curves.These parameters are then incorporated into the machine learning method as physical information to identify the gradient-distributed plastic parameters of the S38C axle.The results indicate that the proposed method based on the physics-informed neural network and multi-fidelity neural network successfully identifies the gradient-distributed plastic parameters of the S38C axles and demonstrates superior prediction accuracy and generalization compared with the purely data-driven machine learning method.展开更多
The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of i...The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of its influence on fluid migration are of crucial importance.While previous studies have revealed that salinity changes can modulate fluid migration,the underlying mechanisms remain poorly understood.We employ molecular dynamics simulations to elucidate how salinity variations in ore-forming fluids modulate the adsorption onto calcite nanopore walls,thereby revealing the microscopic mechanisms governing ore fluid transport through calcite nano-fractures.The results show that the adsorption energy Eint of the solution on the calcite surface increased from -14,948.84±182.48 kcal/mol to -12,144.08±118.2 kcal/mol as salinity increased,which is conducive to the long-range transport of the fluid in the calcite nanopore.展开更多
The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fab...The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fabricate biomimetic gradient lubrication hydrogel through the synergistic integration of three-dimensional(3D)printed metal-organic frameworks(MOFs)nanoparticle network hydrogel skeletons with bioinspired lubrication design.Specifically,robust hydrogel skeletons were engineered through single or multi-material 3D printing,followed by the in situ growth of MOFs nanoparticles within this hydrogel network to create a reinforced,load-bearing architecture.Subsequently,biomimetic lubrication capability was enabled by mechanically coupling another lubricating hydrogel within 3D-printed MOFs nanoparticle network hydrogel skeleton.The superficial layer is highly lubricious to ensure low coefficient of friction(~0.1141)and wear resistance(40,000 cycles),while the deeper layer is stiffer to afford the obligatory mechanical support(fracture strength~2.50 MPa).Furthermore,the gradient architecture stiffness of the hydrogel can be modulated by manipulating the spatial distribution of MOFs within the 3D-printed hydrogel skeleton.As a proof-of-concept,biomimetic gradient hydrogel meniscus structures with C-and O-shaped configurations were constructed by leveraging multi-material 3D printing,demonstrating exceptional lubrication performance.This innovative biomimetic design opens new avenues for creating implantable biomedical gradient lubricating materials with reinforced mechanical and lubrication performance.展开更多
Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emissi...Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emission of these textiles significantly hinders their efficient radiative heat exchange with self-heated objects,thereby posing a significant challenge to their versatile cooling applicability.Herein,we present a bicomponent blow spinning strategy for the production of scalable,ultra-flexible,and healable textiles featuring a tailored dual gradient in both chemical composition and fiber diameter.The gradient in the fiber diameter of this textile introduces a hierarchically porous structure across the sunlight incident area,thereby achieving a competitive solar reflectivity of 98.7%on its outer surface.Additionally,the gradient in the chemical composition of this textile contributes to the formation of Janus infrared-absorbing surfaces:The outer surface demonstrates a high mid-infrared emission,whereas the inner surface shows a broad infrared absorptivity,facilitating radiative heat exchange with underlying self-heated objects.Consequently,this textile demonstrates multi-scenario radiative cooling capabilities,enabling versatile outdoor cooling for unheated objects by 7.8℃ and self-heated objects by 13.6℃,compared to commercial sunshade fabrics.展开更多
Fluid dynamic research on rectangular and trapezoidal fins is aimed at increasing heat transfer by means of large surfaces.The trapezoidal cavity form is compared with its thermal and flow performance,and it is reveal...Fluid dynamic research on rectangular and trapezoidal fins is aimed at increasing heat transfer by means of large surfaces.The trapezoidal cavity form is compared with its thermal and flow performance,and it is revealed that trapezoidal fins tend to be more efficient,particularly when material optimization is critical.Motivated by the increasing need for sustainable energy management,this work analyses the thermal performance of inclined trapezoidal and rectangular porous fins utilising a unique hybrid nanofluid.The effectiveness of nanoparticles in a working fluid is primarily determined by their thermophysical properties;hence,optimising these properties can significantly improve overall performance.This study considers the dispersion of Graphene Oxide(GO)and Molybdenum Disulfide in the base fluid,engine oil.Temperature profiles are analysed by altering the radiative,porosity,wet porous,and angle of inclination parameters.Surface and contour plots are constructed by using the Lobatto IIIa Collocation Method with BVP5C solver in MATLAB and Gradient Descent Optimisation to predict the combined heat transfer rate.According to the study,fluid temperature consistently decreases when the angle of inclination,wet porous parameter,porosity parameter,and radiative parameter increase,suggesting significantly improved heat dissipation.The trapezoidal fin consistently exhibits a superior heat transfer mechanism than a rectangular fin.It is found that the trapezoidal fin transmits heat at a rate that is 0.05%higher than that of the rectangular fin.Validation of the present study is done through the comparison of previous studies.This research provides useful design insights for sophisticated engineering uses,including electrical cooling devices,heat exchangers,radiators,and solar heaters.展开更多
Transforming urban spatial structures to promote green and low-carbon development is an effective strategy.Although prior studies have examined the impact of urban polycentricity on carbon emissions and economic devel...Transforming urban spatial structures to promote green and low-carbon development is an effective strategy.Although prior studies have examined the impact of urban polycentricity on carbon emissions and economic development,research on its role in the synergistic relationship between these factors regarding carbon emission efficiency is limited.Furthermore,existing literature often overlooks nonlinear effects and interactions with other urban variables.This paper analyzed data from 295 Chinese cities in 2020,calculating urban population polycentricity,population dispersion indices,and carbon emission efficiency.Utilizing local spatial autocorrelation tools,we reveal interactions among urban population polycentricity,dispersion,carbon emissions,and carbon emission efficiency.We then employ a gradient boosting decision tree model(GBDT)to explore nonlinear and synergistic effects of polycentric urbanization.Key findings include:1)polycentric urbanization in Chinese cities exhibits significant spatial differentiation characteristics.The Polycentricity index is relatively high in economically developed eastern coastal regions with an overall low level,carbon emissions are concentrated in industrialized north-central cities and some Yangtze River Delta hubs,and carbon emission efficiency is the highest in the Yangtze River Delta while relatively low in Northeast China;there are significant spatially heterogeneous interaction characteristics among population polycentricity,population dispersion,carbon emissions,and carbon emission efficiency.2)Urban population polycentricity contributes 9.42%to total carbon emissions and 6.24%to carbon emission efficiency.3)The polycentricity index has a nonlinear impact on carbon emissions and carbon emission efficiency:no significant effect when below 0.50 or above 0.55,increased carbon emissions in 0.50-0.53,and reduced carbon emissions with improved efficiency in 0.53-0.55.4)The polycentricity index has an interaction effect with other variables;specifically,when the polycentricity index is between 0.53 and 0.55,its interaction with urban gross domestic product(GDP),urban population,urban built-up area,green coverage rate in built-up areas,urban technological expenditure,and the proportion of the output value of the secondary industry will reduce carbon emissions and improve carbon emission efficiency.These findings enhance the understanding of urban spatial structures and carbon emissions,providing valuable insights for policymakers in developing green and low-carbon strategies.展开更多
In this paper,we propose a three-term conjugate gradient method for solving unconstrained optimization problems based on the Hestenes-Stiefel(HS)conjugate gradient method and Polak-Ribiere-Polyak(PRP)conjugate gradien...In this paper,we propose a three-term conjugate gradient method for solving unconstrained optimization problems based on the Hestenes-Stiefel(HS)conjugate gradient method and Polak-Ribiere-Polyak(PRP)conjugate gradient method.Under the condition of standard Wolfe line search,the proposed search direction is the descent direction.For general nonlinear functions,the method is globally convergent.Finally,numerical results show that the proposed method is efficient.展开更多
The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electrom...The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electromagnetic component regulation,layered arrangement structure,and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic loss.On the microscale,the incorporation of magnetic Ni nanoparticles into MXene nanosheets(Ni@MXene)endows suitable intrinsic permittivity and permeability.On the macroscale,the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves,inducing multiple reflection/scattering effects.On this basis,according to the analysis of absorption,reflection,and transmission(A-R-T)power coefficients of layered composites,the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer,electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom layer.Consequently,the layered gradient composite(LG5-10-15)achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RL_(min) of-68.67 dB at 9.85 GHz in 2.05 mm,which is 199.0%,12.6%,and 50.6%higher than non-layered,layered and layered descending gradient composites,respectively.Therefore,this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.展开更多
This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Me...This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Memory soft-sensing model based on Convolutional Neural Network(CNN)and attention mechanism(CNN-ALSTM)that enhances traditional LSTM by integrating CNN and attention mechanism to overcome time lag variations during silicon pulling.The CNN module extracts spatial features from multi-source sensor data,while the attention-enhanced LSTM(ALSTM)dynamically adjusts historical parameter weights,enabling accurate resistivity gradient prediction.Experiments with real production data show that CNN-ALSTM outperforms SVR,FNN,RNN,XGBoost,and GRU,improving prediction accuracy by 11.76%,16.67%,21.05%,30.23%,and 9.09%,respectively.This soft-sensing approach enhances real-time monitoring and optimization of monocrystalline silicon growth.展开更多
Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions ...Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.展开更多
The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.T...The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes.Building on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the scaffolds.The latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are presented.Furthermore,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.展开更多
We combine gradient data from the Macao Science Satellite-1(MSS-1),CHAllenging Minisatellite Payload(CHAMP),Swarm-A,and Swarm-C satellites to develop a 110-degree lithospheric magnetic field model.We then comprehensiv...We combine gradient data from the Macao Science Satellite-1(MSS-1),CHAllenging Minisatellite Payload(CHAMP),Swarm-A,and Swarm-C satellites to develop a 110-degree lithospheric magnetic field model.We then comprehensively evaluate the performance of the model by power spectral comparisons,correlation analyses,sensitivity matrix assessments,and comparisons with existing lithospheric field models.Results showed that using near east–west gradient data from MSS-1 significantly enhances the model correlation in the spherical harmonic degree(N) range of 45–60 while also mitigating the decline in correlation at higher degrees(N > 60).Furthermore,the unique orbital characteristics of MSS-1 enable its gradient data to provide substantial contributions to modeling in the mid-to low-latitude regions.With continued data acquisition from MSS-1 and further optimization of data processing methods,the performance of the model is expected to improve.展开更多
Rolling contact fatigue performance is among the most important issues for applications of bearing steels.In this work,a recently developed surface modification technique,surface mechanical rolling treatment,was appli...Rolling contact fatigue performance is among the most important issues for applications of bearing steels.In this work,a recently developed surface modification technique,surface mechanical rolling treatment,was applied on a rare-earth addition bearing steel.And rolling contact fatigue behavior of treated samples was compared with that of as-received counterparts at different contacting stresses.The results demonstrated that a 700μm-thick gradient nanostructured surface layer is produced on samples by surface mechanical rolling treatment.The grain size decreases while the microhardness increases gradually with decreasing depth,reaching~23 nm and~10.2 GPa,respectively,at the top surface.Consequently,the rolling contact fatigue property is significantly enhanced.The characteristic life of treated samples is~3.2 times that of untreated counterparts according to Weibull curves at 5.6 GPa.Analyses of fatigue mechanisms demonstrated that the gradient nanostructured surface layer might not only retard material degradation and microcrack formation,but also prolong the steady-state elastic response stage under rolling contact fatigue.展开更多
Deep learning(DL)has become a crucial technique for predicting the El Niño-Southern Oscillation(ENSO)and evaluating its predictability.While various DL-based models have been developed for ENSO predictions,many f...Deep learning(DL)has become a crucial technique for predicting the El Niño-Southern Oscillation(ENSO)and evaluating its predictability.While various DL-based models have been developed for ENSO predictions,many fail to capture the coherent multivariate evolution within the coupled ocean-atmosphere system of the tropical Pacific.To address this three-dimensional(3D)limitation and represent ENSO-related ocean-atmosphere interactions more accurately,a novel this 3D multivariate prediction model was proposed based on a Transformer architecture,which incorporates a spatiotemporal self-attention mechanism.This model,named 3D-Geoformer,offers several advantages,enabling accurate ENSO predictions up to one and a half years in advance.Furthermore,an integrated gradient method was introduced into the model to identify the sources of predictability for sea surface temperature(SST)variability in the eastern equatorial Pacific.Results reveal that the 3D-Geoformer effectively captures ENSO-related precursors during the evolution of ENSO events,particularly the thermocline feedback processes and ocean temperature anomaly pathways on and off the equator.By extending DL-based ENSO predictions from one-dimensional Niño time series to 3D multivariate fields,the 3D-Geoformer represents a significant advancement in ENSO prediction.This study provides details in the model formulation,analysis procedures,sensitivity experiments,and illustrative examples,offering practical guidance for the application of the model in ENSO research.展开更多
基金supported by the National Key Research and Development Program of China(2023YFB3809300).
文摘Recycling spent lithium-ion(Li+)batteries is critical for achieving environmental conservation and the strategic recovery of essential resources.Compared with conventional methods for recovering cathode materials,which are energy-intensive and prone to secondary pollution,the direct regeneration approach has emerged as a rapid and highly efficient method,gaining widespread attention in recent years.However,this approach faces major challenges,including degraded electrochemical performances and limited economic value.This study,therefore,proposes a high-value direct regeneration strategy to convert degraded spent LiFePO_(4)(S-LFP)into a gradient manganese(Mn)-doped regenerated LiFe_(0.7)Mn_(0.3)PO_(4)/C(R-LFMP)composite.This method leverages the inherent microcracks and Li vacancies present in S-LFP,likely acting as diffusion channels for the Mn^(2+)/Li^(+)ions.Through a two-step mechanochemical ball-milling and carbothermal reduction process,this approach achieves simultaneous Li replenishment and surface-localised Mn gradient doping with enhanced structural control.Notably,the R-LFMP exhibits an exceptional electrochemical performance.At 0.1 C,it delivers a discharge capacity of 161.4 mA h g^(−1)and an energy density of 563.5 Wh kg^(−1)(representing a 60.5%improvement over S-LFP).Additionally,it maintains 83%capacity retention after 900 cycles at 0.5C,a considerable enhancement compared to commercial LFMP(62%).Furthermore,the regenerated cathode material generates a net profit of$7.102 kg^(−1),surpassing the profitability of conventional recycling methods by 90%.Overall,this study introduces a transformative and sustainable LFP regeneration technology,achieving breakthroughs in electrochemical restoration and high-value recycling,while paving the way for the closed-loop utilisation of LFP-based energy storage systems.
基金supported by the National Natural Science Foundation of China (Grant Nos.12274313 and 62375234)the Gusu Leading Talent Plan for Scientific and Technological Innovation and Entrepreneurship (Grant No.ZXL2024400)。
文摘Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with phase gradient modulation can be used to achieve illusion optics,featuring the advantages of simple geometric structure and feasible implementation compared with the well-known transformation optics method.The underlying mechanism is the anomalous diffraction law caused by the phase gradient,which provides a theoretical basis for freely manipulating the propagation path of light.By considering a specific example,we will demonstrate that the phase gradient can transform spatial coordinates in real space into illusion space,thereby converting a plane in real space into a curved surface structure in illusion space to achieve the illusion effect.This approach provides a viable alternative to transformation optics for designing illusion devices.
基金supported by the National Natural Science Foundation of China(12304102,62574029)Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0479)+1 种基金Science and Technology Research Project of Chongqing Education Committee(KJQN202400558)Doctoral Scientific Research Fund of Chongqing Normal University(23XLB029)。
文摘β-Ga_(2)O_(3)is a promising candidate for solarblind ultraviolet photodetection owing to its suitable bandgap of approximately 4.9 eV,excellent photoresponse characteristics,and high stability.However,the lack of a sufficient driving force within the material leads to extensive bulk charge recombination,limiting its photocurrent and thus posing significant challenges in designing high-performance Ga_(2)O_(3)-based photodetection.In this study,we propose a gradient doping strategy to achieve a Sn-doping concentration gradient along theβ-Ga_(2)O_(3)film thickness.By combining sol-gel synthesis with rapid thermal annealing,a spatially graded band structure with a full-space built-in electric field is constructed,which increases the width of band bending over a large region and is crucial for significantly enhancing carrier separation and transport in the bulk.The resulting gradient Sn-dopedβ-Ga_(2)O_(3)enables exceptional photoelectric performance without an external bias under 254 nm irradiation,including a superior responsivity of 66.88 mA W^(-1),a high detectivity of 8.12×10^(11)Jones,and a fast rise/decay time of 79/65 ms,outstanding most existing similar reported photoelectrochemical(PEC)type optoelectronic devices.Additionally,the device exhibits excellent long-term stability and enables high-resolution underwater ultraviolet imaging.This study demonstrates that the gradient doping strategy provides a feasible approach for enhancing the PEC performance ofβ-Ga_(2)O_(3)photoelectrodes.
基金supported by the National Research Foundation of Korea(NRF)grants(Grant Nos.RS-2020-NR049594 and RS-2022-NR071877)the Korea Agency for Infrastructure Technology Advancement under the Ministry of Land,Infrastructure and Transport(Grant No.RS-2024-00410248).
文摘Suffusion refers to the loss of fineparticles within the soil matrix without any associated volume change,induced by hydrodynamic forces.This study investigated the suffusion of sand-clay mixtures through one-dimensional soil column experiments under a stepwise increase in hydraulic gradient(i),aiming to evaluate the critical hydraulic gradient(icrit)as a function of the size ratio between sand and clay,clay type,and ionic concentration.It was found that icrit was less than 0.1 for all sand-clay mixtures examined in this study.In addition,the lower peak concentrations of filtrated clay observed in sand-illite mixtures,compared to those of sand-kaolinite mixtures at the same level of i,suggest that illite particles are more susceptible to suffusion.Overall,the observed breakthrough curves,mass fraction of filtrated clay,volume of outflow,and total injection time presented in this study highlight the importance of considering clay type,sand-to-clay size ratio,and ionic concentration when assessing the suffusion behavior of clay-containing soils under a stepwise increase in hydraulic gradient.
基金supported by Natural Science Foundation of Xiamen,China(No.3502Z20227232)the STS Project of Fujian-CAS(No.2023T3018)Bureau of International Cooperation,Chinese Academy of Sciences(No.322GJHZ2022035MI).
文摘Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key factors in anammox bacteria enrichment.This study investigated the mechanisms driving anammox bacteria enrichment in lab-scale simulated CWs treating high-nitrogen wastewater,focusing on bacterial community re-sponses across wetland layers with various strategies,including continuous up-flow influent,nitrogen loading increase,effluent recirculation,intermittent influent,and anammox bacteria inoculation.Results showed that total relative and absolute abundances of anammox bacteria ranged from 0.77%to 12.50%and from 0.13 to 6.46×10^(7) copies/g,respectively.Dissolved oxygen and pH had significant positive correlations with the absolute abundance of anammox bacteria,while organic matter and nitrate negatively impacted their relative abundance.Permutational multivariate analysis of variance indicated that spatial heterogeneity explained more variation in anammox bacteria abundance(43.44%)compared to operational strategies(8.58%).In terms of microbial interactions,60 dominant species exhibited potential correlations with anammox bacteria,comprising 170 interactions(105 positive and 65 negative),which suggested that anammox bacteria generally foster cooperative relationships with dominant bacteria.Notably,significant interspecies interactions were observed between Candidatus Kuenenia(dominant anammox bacteria in CWs)and species within the genera Chitinivibrio-nia and Anaerolineaceae,suggesting that microbial interactions primarily manifest as indirect facilitative effects rather than direct mutualistic relationships.Given that the Normalized Stochasticity Ratio in CWs were<50%,this study inferred that environmental gradients have greater influence on anammox bacteria than microbial interactions.
基金supported by the School of Engineering and Digital Sciences of Nazarbayev University,Astana,Kazakhstan(to CE)。
文摘The osteochondral(OC)interface exhibits a mineral gradient,varying in thickness by several hundred micrometers across different species.Disruptions in this interface damage OC tissues,leading to osteoarthritis.The natural architecture and composition of native OC interfaces can be replicated using biomaterial scaffolds via regenerative engineering approaches.A novel one-step bioextrusion process was employed to fabricate a unitary synthetic graft(USG),which mimics the native OC interface’s mineral concentration gradient.This novel USG is composed of an agarose-based cartilage layer and a bone layer,consisting of agarose enriched with 20%(200 g/L)hydroxyapatite.The USG features a gradient interface with mineral concentrations transitioning from 0%to 20%(mass fraction),mimicking the transition between the cartilage and bone.Thermogravimetric analysis revealed that the gradient transition lengths of the graft and native OC tissue harvested from bovine knees were similar((647±21)vs.(633±124)μm).The linear viscoelastic properties of the grafts,which were evaluated using strain sweep and frequency sweep tests with oscillatory shear,indicated a dominant storage modulus over loss modulus similar to that of native OC tissues.The compressive and stress relaxation behaviors of the USGs demonstrated that the graft maintained structural integrity under mechanical stress.Viability assays performed after bioextrusion showed that chondrocytes and human fetal osteoblast cells successfully integrated and survived within their designated regions of the graft.The novel USGs exhibit properties similar to native OC tissue and are promising candidates for regenerating OC defects and restoring knee joint functionality.
基金supported by the National Key Research and Development Plan(Grant No.2022YFB3401901)the National Natural Science Foundation of China(Grant Nos.12192210,12192214,12072295,and 12222209)+1 种基金Independent Project of State Key Laboratory of Rail Transit Vehicle System(Grant No.2023TPL-T03)Fundamental Research Funds for the Central Universities(Grant No.2682023CG004).
文摘The S38C railway axle undergoes induction hardening,resulting in a gradient-distributed microstructure and mechanical properties.The accurate identification of gradient-distributed plastic parameters for the S38C axle remains a challenging task.To tackle this challenge,the present study proposes a novel approach for identifying the gradient-distributed plastic parameters for the S38C axle by integrating nano-indentation techniques with the machine learning method.Firstly,nano-indentation tests are conducted along the radial direction of the S38C axle to obtain the gradient-distributed load-displacement curves,nano-hardness,and elastic modulus.Subsequently,the dimensionless analysis is performed to obtain the representative stress,strain,and yield stress from load-displacement curves.These parameters are then incorporated into the machine learning method as physical information to identify the gradient-distributed plastic parameters of the S38C axle.The results indicate that the proposed method based on the physics-informed neural network and multi-fidelity neural network successfully identifies the gradient-distributed plastic parameters of the S38C axles and demonstrates superior prediction accuracy and generalization compared with the purely data-driven machine learning method.
基金financed jointly by the National Major Science and Technology Special Project on Deep Earth Exploration(2024ZD1001701-5)the National Natural Science Foundation of China(42472127,42172086)+2 种基金the Yunnan Major Project of Basic Research(202401BN070001-002)Yunnan Mineral Resources Prediction and Evaluation Engineering Research Center(2011)Innovation Team Program of Kunming University of Science and Technology,Yunnan Province。
文摘The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of its influence on fluid migration are of crucial importance.While previous studies have revealed that salinity changes can modulate fluid migration,the underlying mechanisms remain poorly understood.We employ molecular dynamics simulations to elucidate how salinity variations in ore-forming fluids modulate the adsorption onto calcite nanopore walls,thereby revealing the microscopic mechanisms governing ore fluid transport through calcite nano-fractures.The results show that the adsorption energy Eint of the solution on the calcite surface increased from -14,948.84±182.48 kcal/mol to -12,144.08±118.2 kcal/mol as salinity increased,which is conducive to the long-range transport of the fluid in the calcite nanopore.
基金support from the National Key Research and Development Program of China(2022YFB4600101)the National Natural Science Foundation of China(52505231 and 52175201)+5 种基金the Key R&D Program of Shandong Province(2024CXPT035)the Research Program of Science and Technology Department of Gansu Province(24JRRA059,24JRRA044 and 24ZDGA014)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(AMGM2024F12)the Innovation and Entrepreneurship Team Prject of YEDA(2021TD007)the Special Supporting Project for Provincial Leading Talents of Yantai,the Major Program(ZYFZFX-2)the Fundamental Research Special Zone Project of the Lanzhou Institute of Chemical Physics,CAS,the Special Research Assistant Project of the Chinese Academy of Sciences,and the Taishan Scholars Program.
文摘The development of gradient lubrication materials is critical for numerous biomedical applications,particularly in magnifying mechanical properties and service longevity.Herein,we present an innovative approach to fabricate biomimetic gradient lubrication hydrogel through the synergistic integration of three-dimensional(3D)printed metal-organic frameworks(MOFs)nanoparticle network hydrogel skeletons with bioinspired lubrication design.Specifically,robust hydrogel skeletons were engineered through single or multi-material 3D printing,followed by the in situ growth of MOFs nanoparticles within this hydrogel network to create a reinforced,load-bearing architecture.Subsequently,biomimetic lubrication capability was enabled by mechanically coupling another lubricating hydrogel within 3D-printed MOFs nanoparticle network hydrogel skeleton.The superficial layer is highly lubricious to ensure low coefficient of friction(~0.1141)and wear resistance(40,000 cycles),while the deeper layer is stiffer to afford the obligatory mechanical support(fracture strength~2.50 MPa).Furthermore,the gradient architecture stiffness of the hydrogel can be modulated by manipulating the spatial distribution of MOFs within the 3D-printed hydrogel skeleton.As a proof-of-concept,biomimetic gradient hydrogel meniscus structures with C-and O-shaped configurations were constructed by leveraging multi-material 3D printing,demonstrating exceptional lubrication performance.This innovative biomimetic design opens new avenues for creating implantable biomedical gradient lubricating materials with reinforced mechanical and lubrication performance.
基金financial support from the National Natural Science Foundation of China(Grant No.52273067,52233006)the Fundamental Research Funds for the Central Universities(Grant No.2232023A-03)+3 种基金the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(Grant No.23SG29)the Natural Science Foundation of Shanghai(Grant No.24ZR1402400)the Shanghai Scientific and Technological Innovation Project(Grant No.24520713000)Innovation Program of Shanghai Municipal Education Commission(Grant No.2021-01-07-00-03-E00108).
文摘Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emission of these textiles significantly hinders their efficient radiative heat exchange with self-heated objects,thereby posing a significant challenge to their versatile cooling applicability.Herein,we present a bicomponent blow spinning strategy for the production of scalable,ultra-flexible,and healable textiles featuring a tailored dual gradient in both chemical composition and fiber diameter.The gradient in the fiber diameter of this textile introduces a hierarchically porous structure across the sunlight incident area,thereby achieving a competitive solar reflectivity of 98.7%on its outer surface.Additionally,the gradient in the chemical composition of this textile contributes to the formation of Janus infrared-absorbing surfaces:The outer surface demonstrates a high mid-infrared emission,whereas the inner surface shows a broad infrared absorptivity,facilitating radiative heat exchange with underlying self-heated objects.Consequently,this textile demonstrates multi-scenario radiative cooling capabilities,enabling versatile outdoor cooling for unheated objects by 7.8℃ and self-heated objects by 13.6℃,compared to commercial sunshade fabrics.
基金supported by the“Regional Innovation System&Education(RISE)”through the Seoul RISE Center,funded by the Ministry of Education(MOE)and the Seoul Metropolitan Government(2025-RISE-01-027-04).
文摘Fluid dynamic research on rectangular and trapezoidal fins is aimed at increasing heat transfer by means of large surfaces.The trapezoidal cavity form is compared with its thermal and flow performance,and it is revealed that trapezoidal fins tend to be more efficient,particularly when material optimization is critical.Motivated by the increasing need for sustainable energy management,this work analyses the thermal performance of inclined trapezoidal and rectangular porous fins utilising a unique hybrid nanofluid.The effectiveness of nanoparticles in a working fluid is primarily determined by their thermophysical properties;hence,optimising these properties can significantly improve overall performance.This study considers the dispersion of Graphene Oxide(GO)and Molybdenum Disulfide in the base fluid,engine oil.Temperature profiles are analysed by altering the radiative,porosity,wet porous,and angle of inclination parameters.Surface and contour plots are constructed by using the Lobatto IIIa Collocation Method with BVP5C solver in MATLAB and Gradient Descent Optimisation to predict the combined heat transfer rate.According to the study,fluid temperature consistently decreases when the angle of inclination,wet porous parameter,porosity parameter,and radiative parameter increase,suggesting significantly improved heat dissipation.The trapezoidal fin consistently exhibits a superior heat transfer mechanism than a rectangular fin.It is found that the trapezoidal fin transmits heat at a rate that is 0.05%higher than that of the rectangular fin.Validation of the present study is done through the comparison of previous studies.This research provides useful design insights for sophisticated engineering uses,including electrical cooling devices,heat exchangers,radiators,and solar heaters.
基金Under the auspices of National Natural Science Foundation of China(No.42571300)。
文摘Transforming urban spatial structures to promote green and low-carbon development is an effective strategy.Although prior studies have examined the impact of urban polycentricity on carbon emissions and economic development,research on its role in the synergistic relationship between these factors regarding carbon emission efficiency is limited.Furthermore,existing literature often overlooks nonlinear effects and interactions with other urban variables.This paper analyzed data from 295 Chinese cities in 2020,calculating urban population polycentricity,population dispersion indices,and carbon emission efficiency.Utilizing local spatial autocorrelation tools,we reveal interactions among urban population polycentricity,dispersion,carbon emissions,and carbon emission efficiency.We then employ a gradient boosting decision tree model(GBDT)to explore nonlinear and synergistic effects of polycentric urbanization.Key findings include:1)polycentric urbanization in Chinese cities exhibits significant spatial differentiation characteristics.The Polycentricity index is relatively high in economically developed eastern coastal regions with an overall low level,carbon emissions are concentrated in industrialized north-central cities and some Yangtze River Delta hubs,and carbon emission efficiency is the highest in the Yangtze River Delta while relatively low in Northeast China;there are significant spatially heterogeneous interaction characteristics among population polycentricity,population dispersion,carbon emissions,and carbon emission efficiency.2)Urban population polycentricity contributes 9.42%to total carbon emissions and 6.24%to carbon emission efficiency.3)The polycentricity index has a nonlinear impact on carbon emissions and carbon emission efficiency:no significant effect when below 0.50 or above 0.55,increased carbon emissions in 0.50-0.53,and reduced carbon emissions with improved efficiency in 0.53-0.55.4)The polycentricity index has an interaction effect with other variables;specifically,when the polycentricity index is between 0.53 and 0.55,its interaction with urban gross domestic product(GDP),urban population,urban built-up area,green coverage rate in built-up areas,urban technological expenditure,and the proportion of the output value of the secondary industry will reduce carbon emissions and improve carbon emission efficiency.These findings enhance the understanding of urban spatial structures and carbon emissions,providing valuable insights for policymakers in developing green and low-carbon strategies.
基金Supported by the Science and Technology Project of Guangxi(Guike AD23023002)。
文摘In this paper,we propose a three-term conjugate gradient method for solving unconstrained optimization problems based on the Hestenes-Stiefel(HS)conjugate gradient method and Polak-Ribiere-Polyak(PRP)conjugate gradient method.Under the condition of standard Wolfe line search,the proposed search direction is the descent direction.For general nonlinear functions,the method is globally convergent.Finally,numerical results show that the proposed method is efficient.
基金support for this work by Key Research and Development Project of Henan Province(Grant.No.241111232300)the National Natural Science Foundation of China(Grant.No.52273085 and 52303113)the Open Fund of Yaoshan Laboratory(Grant.No.2024003).
文摘The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electromagnetic component regulation,layered arrangement structure,and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic loss.On the microscale,the incorporation of magnetic Ni nanoparticles into MXene nanosheets(Ni@MXene)endows suitable intrinsic permittivity and permeability.On the macroscale,the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves,inducing multiple reflection/scattering effects.On this basis,according to the analysis of absorption,reflection,and transmission(A-R-T)power coefficients of layered composites,the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer,electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom layer.Consequently,the layered gradient composite(LG5-10-15)achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RL_(min) of-68.67 dB at 9.85 GHz in 2.05 mm,which is 199.0%,12.6%,and 50.6%higher than non-layered,layered and layered descending gradient composites,respectively.Therefore,this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.
文摘This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Memory soft-sensing model based on Convolutional Neural Network(CNN)and attention mechanism(CNN-ALSTM)that enhances traditional LSTM by integrating CNN and attention mechanism to overcome time lag variations during silicon pulling.The CNN module extracts spatial features from multi-source sensor data,while the attention-enhanced LSTM(ALSTM)dynamically adjusts historical parameter weights,enabling accurate resistivity gradient prediction.Experiments with real production data show that CNN-ALSTM outperforms SVR,FNN,RNN,XGBoost,and GRU,improving prediction accuracy by 11.76%,16.67%,21.05%,30.23%,and 9.09%,respectively.This soft-sensing approach enhances real-time monitoring and optimization of monocrystalline silicon growth.
基金supported by the Fundamental Research Funds of Chinese Academy of Forestry(Nos.CAFYBB2022SY037,CAFYBB2021ZA002 and CAFYBB2022QC002)the Basic Research Foundation of Yunnan Province(Grant No.202201AT070264).
文摘Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.
基金supported by the National Natural Science Foundation of China(Grant No.52473121,52403370 and 52221006)Fundamental Research Funds for the Central Universities(buctrc202020,buctrc202312).
文摘The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes.Building on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the scaffolds.The latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are presented.Furthermore,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.
基金the support of the National Natural Science Foundation of China (Nos. 42250103, 41974073, and 41404053)the Macao Foundation and the preresearch project of Civil Aerospace Technologies (Nos. D020308 and D020303)funded by China’s National Space Administration, the Specialized Research Fund for State Key Laboratories。
文摘We combine gradient data from the Macao Science Satellite-1(MSS-1),CHAllenging Minisatellite Payload(CHAMP),Swarm-A,and Swarm-C satellites to develop a 110-degree lithospheric magnetic field model.We then comprehensively evaluate the performance of the model by power spectral comparisons,correlation analyses,sensitivity matrix assessments,and comparisons with existing lithospheric field models.Results showed that using near east–west gradient data from MSS-1 significantly enhances the model correlation in the spherical harmonic degree(N) range of 45–60 while also mitigating the decline in correlation at higher degrees(N > 60).Furthermore,the unique orbital characteristics of MSS-1 enable its gradient data to provide substantial contributions to modeling in the mid-to low-latitude regions.With continued data acquisition from MSS-1 and further optimization of data processing methods,the performance of the model is expected to improve.
基金The financial supports by the Chinese Academy of Sciences(Nos.XDC04030300 and XDB0510303)CAS-HK Joint Laboratory of Nanomaterials and MechanicsShenyang National Laboratory for Materials Science are acknowledged.
文摘Rolling contact fatigue performance is among the most important issues for applications of bearing steels.In this work,a recently developed surface modification technique,surface mechanical rolling treatment,was applied on a rare-earth addition bearing steel.And rolling contact fatigue behavior of treated samples was compared with that of as-received counterparts at different contacting stresses.The results demonstrated that a 700μm-thick gradient nanostructured surface layer is produced on samples by surface mechanical rolling treatment.The grain size decreases while the microhardness increases gradually with decreasing depth,reaching~23 nm and~10.2 GPa,respectively,at the top surface.Consequently,the rolling contact fatigue property is significantly enhanced.The characteristic life of treated samples is~3.2 times that of untreated counterparts according to Weibull curves at 5.6 GPa.Analyses of fatigue mechanisms demonstrated that the gradient nanostructured surface layer might not only retard material degradation and microcrack formation,but also prolong the steady-state elastic response stage under rolling contact fatigue.
基金Supported by the Laoshan Laboratory(No.LSKJ202202402)the National Natural Science Foundation of China(No.42030410)+2 种基金the Startup Foundation for Introducing Talent of Nanjing University of Information Science&Technology,and Jiangsu Innovation Research Group(No.JSSCTD 202346)supported by the China National Postdoctoral Program for Innovative Talents(No.BX20240169)the China Postdoctoral Science Foundation(No.2141062400101)。
文摘Deep learning(DL)has become a crucial technique for predicting the El Niño-Southern Oscillation(ENSO)and evaluating its predictability.While various DL-based models have been developed for ENSO predictions,many fail to capture the coherent multivariate evolution within the coupled ocean-atmosphere system of the tropical Pacific.To address this three-dimensional(3D)limitation and represent ENSO-related ocean-atmosphere interactions more accurately,a novel this 3D multivariate prediction model was proposed based on a Transformer architecture,which incorporates a spatiotemporal self-attention mechanism.This model,named 3D-Geoformer,offers several advantages,enabling accurate ENSO predictions up to one and a half years in advance.Furthermore,an integrated gradient method was introduced into the model to identify the sources of predictability for sea surface temperature(SST)variability in the eastern equatorial Pacific.Results reveal that the 3D-Geoformer effectively captures ENSO-related precursors during the evolution of ENSO events,particularly the thermocline feedback processes and ocean temperature anomaly pathways on and off the equator.By extending DL-based ENSO predictions from one-dimensional Niño time series to 3D multivariate fields,the 3D-Geoformer represents a significant advancement in ENSO prediction.This study provides details in the model formulation,analysis procedures,sensitivity experiments,and illustrative examples,offering practical guidance for the application of the model in ENSO research.
