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
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
裂缝型储层是一种含流体的裂缝-孔隙介质,其裂缝参数的定量表征对非常规油气藏的勘探与开发具有重要意义。然而,传统以振幅信息为主的储层预测方法存在局限性,难以全面揭示裂缝型储层的复杂特性。本文针对含饱和流体的正交裂缝型储层,...裂缝型储层是一种含流体的裂缝-孔隙介质,其裂缝参数的定量表征对非常规油气藏的勘探与开发具有重要意义。然而,传统以振幅信息为主的储层预测方法存在局限性,难以全面揭示裂缝型储层的复杂特性。本文针对含饱和流体的正交裂缝型储层,深入分析了含水平和垂直正交裂缝介质的速度频散与衰减特性,并采用各向异性反射率法模拟了单界面频散砂岩储层振幅随偏移距变化(amplitude variation with offset,AVO)的频变响应特征。在此基础上,构建了以水平和垂直正交裂缝模型响应为驱动的贝叶斯反演框架,实现了对裂缝型储层中孔隙度、裂缝密度及裂缝半径的多参数定量反演。研究结果表明,孔隙度、裂缝密度及裂缝半径对速度频散表现出高度敏感性,且在低频时PP波频变反射系数随频率和入射角发生显著变化,振幅随入射角的增大线性增加,揭示了裂缝参数对频变AVO响应有重要影响。反演结果表明,所提出的反演方法在不同裂缝参数条件下,后验概率分布都具有较高精度,尤其在小尺度裂缝型储层中,对裂缝半径预测表现出更好的适用性和可靠性。展开更多
The present study investigates wake-induced bypass transition of boundary layers on a flat plate subjected to favorable and adverse pressure gradients. The aim is to exploit unsteady effects in order to design an aft-...The present study investigates wake-induced bypass transition of boundary layers on a flat plate subjected to favorable and adverse pressure gradients. The aim is to exploit unsteady effects in order to design an aft-loaded turbine blade without increasing the profile loss, as has been achieved for low pressure turbine blades. First of all, this fundamental study is to reveal the effect of the Strouhal number, which changed by using different numbers of wake generating bars. Detailed boundary layer measurements were conducted using two hot-wire probes. A passage-contouring device was employed to generate a pressure gradient on the test model, which was typical to that generated by an aft-loaded turbine blade. A spoked-wheel-type wake generator was used to create periodic wakes in front of the flat plate. It was found that the wake passage induces a significant change in the flow structure downstream of the flow acceleration region.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 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.
文摘裂缝型储层是一种含流体的裂缝-孔隙介质,其裂缝参数的定量表征对非常规油气藏的勘探与开发具有重要意义。然而,传统以振幅信息为主的储层预测方法存在局限性,难以全面揭示裂缝型储层的复杂特性。本文针对含饱和流体的正交裂缝型储层,深入分析了含水平和垂直正交裂缝介质的速度频散与衰减特性,并采用各向异性反射率法模拟了单界面频散砂岩储层振幅随偏移距变化(amplitude variation with offset,AVO)的频变响应特征。在此基础上,构建了以水平和垂直正交裂缝模型响应为驱动的贝叶斯反演框架,实现了对裂缝型储层中孔隙度、裂缝密度及裂缝半径的多参数定量反演。研究结果表明,孔隙度、裂缝密度及裂缝半径对速度频散表现出高度敏感性,且在低频时PP波频变反射系数随频率和入射角发生显著变化,振幅随入射角的增大线性增加,揭示了裂缝参数对频变AVO响应有重要影响。反演结果表明,所提出的反演方法在不同裂缝参数条件下,后验概率分布都具有较高精度,尤其在小尺度裂缝型储层中,对裂缝半径预测表现出更好的适用性和可靠性。
文摘The present study investigates wake-induced bypass transition of boundary layers on a flat plate subjected to favorable and adverse pressure gradients. The aim is to exploit unsteady effects in order to design an aft-loaded turbine blade without increasing the profile loss, as has been achieved for low pressure turbine blades. First of all, this fundamental study is to reveal the effect of the Strouhal number, which changed by using different numbers of wake generating bars. Detailed boundary layer measurements were conducted using two hot-wire probes. A passage-contouring device was employed to generate a pressure gradient on the test model, which was typical to that generated by an aft-loaded turbine blade. A spoked-wheel-type wake generator was used to create periodic wakes in front of the flat plate. It was found that the wake passage induces a significant change in the flow structure downstream of the flow acceleration region.
