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Defect-engineered gradient reconstruction for the upcycling of spent LiFePO_(4)to generate high-value LiFe_(1−x)Mn_(x)PO_(4)/C cathodes
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作者 Shuaijing Ji Yanqiong Tan +6 位作者 Junwei Wang Fengqian Wang Danpeng Cheng Zhenxing Wang Zhongwen Ouyang Shun Tang Yuancheng Cao 《Journal of Energy Chemistry》 2026年第1期306-316,I0008,共12页
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
关键词 Spent LiFePO_(4)recycling Defect-guided gradient reconstruction gradient manganese doping Closed-loop recycling Economic viability
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Illusion Optics via Phase-Gradient Metasurfaces
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作者 Zhaoyao Pan Jinpeng Yang Yadong Xu 《Chinese Physics Letters》 2026年第1期31-36,共6页
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
关键词 transformation optics anomalous diffraction law illusion opticsfeaturing flexible light manipulationwith illusion optics anomalous diffraction phase gradient modulation phase gradient metasurfaces
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Suffusion of sand-clay mixtures under stepwise increase in hydraulic gradient
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作者 Jooho Lee Yerim Yang +1 位作者 Hangseok Choi Jongmuk Won 《Journal of Rock Mechanics and Geotechnical Engineering》 2026年第2期1587-1600,共14页
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
关键词 Critical hydraulic gradient Suffusion Breakthrough curve Sand-clay mixture Ionic concentration Clay mineralogy
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Mechanisms driving anammox bacteria enrichment in constructed wetlands for self-purification of high-nitrogen polluted wastewater:Environmental gradients and microbial interactions
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作者 Lin Liu Jie Li +2 位作者 Yu Xin Quan-Bao Zhao Yu-Ming Zheng 《Journal of Environmental Sciences》 2026年第1期44-53,共10页
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
关键词 Self-purifying capacity Anammox bacteria Environmental gradient Constructed wetland Co-occurrence network Nature-based solution
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Bioextrusion of hydrogels with controlled mineral gradients for regenerative engineering of osteochondral interfaces
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作者 Xiao Zhao Weiwei Wang +2 位作者 Xiaojun Yu Dilhan M.Kalyon Cevat Erisken 《Bio-Design and Manufacturing》 2026年第1期122-136,I0019,I0020,共17页
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
关键词 Osteochondral(OC)interface Mineral gradient Bioextrusion Hydrogel scaffold Regenerative engineering
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Physics-informed machine learning for identifying gradient-distributed plastic parameters of the S38C axle by nano-indentation
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作者 Siyu Li Lvfeng Jiang +4 位作者 Yanan Hu Jian Li Xu Zhang Qianhua Kan Guozheng Kang 《Acta Mechanica Sinica》 2026年第1期105-121,共17页
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
关键词 S38C axle Nanoindentation Physics-informed machine learning gradient structure Plastic parameters
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Digital light processing 3D printing of ceramics for W-band gradient refractive index metalens
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作者 Wuzhao Li Siqian Wu +2 位作者 Jin Chen Rong Wang Qi Ge 《International Journal of Extreme Manufacturing》 2026年第1期601-616,共16页
Gradient refractive index(GRIN)metalenses are increasingly valued in high-frequency communication due to their exceptional radiation performance.Ceramics with high dielectric constants and low dielectric losses are id... Gradient refractive index(GRIN)metalenses are increasingly valued in high-frequency communication due to their exceptional radiation performance.Ceramics with high dielectric constants and low dielectric losses are ideal candidates for GRIN metalenses.Digital light processing(DLP)3D printing provides a feasible and efficient approach for manufacturing ceramic GRIN metalenses.However,the scattering of ultraviolet(UV)light by ceramic particles in the slurry reduces the printing accuracy of DLP technology,making it difficult to achieve the intricate structural features required for GRIN metalenses in high-frequency communication.In this work,we propose an approach to improve printing accuracy by optimizing the ceramic slurry composition and implementing a dimensional compensation design strategy.Utilizing geometric optics and the S-parameter inversion method,we design a GRIN metalens consisting of two distinct types of subwavelength unit cells(Y-shaped and circular hole geometries)with a minimum feature size of 160μm.Through a refined slurry formulation and precise design parameter compensation,high-fidelity ceramic GRIN metalenses are successfully fabricated.The fabricated metalens exhibits a maximum gain enhancement of 18.4 dBi and a deflection angle of±30°over a bandwidth of 37.84% in the W-band(75-110 GHz).The highly directional far-field beam radiation and efficient beam steering capabilities highlight the potential of ceramic GRIN metalenses for applications in satellite communications,radar systems,and other high-frequency technologies. 展开更多
关键词 3D printing CERAMICS digital light processing gradient refractive index metalens
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Fluid migration in calcite nanopores under salinity gradients:Insights from molecular dynamics
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作者 Yi Chen Yan Zhang +1 位作者 Run-Sheng Han Lei Wang 《Acta Geochimica》 2026年第1期185-203,共19页
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
关键词 Fluid transport dynamics Salinity gradient regulation Calcite nanopores Molecular dynamics simulation
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Biomimetic Gradient Lubrication Hydrogel Contrived by Self-Reinforced MOFs Nanoparticle Network
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作者 Desheng Liu Yixian Wang +8 位作者 Changcheng Bai Danli Hu Xingxing Yang Yaozhong Lu Tao Wu Fei Zhai Pan Jiang Xiaolong Wang Weimin Liu 《Nano-Micro Letters》 2026年第5期217-234,共18页
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
关键词 Biomimetic gradient architecture DIW 3D printing Lubricating hydrogel MOFs nanoparticle network Slippery meniscus
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Scalable and Healable Gradient Textiles for Multi‑Scenario Radiative Cooling via Bicomponent Blow Spinning
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作者 Baiyu Ji Yufeng Wang +6 位作者 Ying Liu Yongxu Zhao Fankun Xu Jian Huang Yue‑EMiao Chao Zhang Tianxi Liu 《Nano-Micro Letters》 2026年第3期338-353,共16页
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
关键词 gradient cooling textile Bicomponent blow spinning Janus spectral selectivity Radiative heat exchange Multi-scenario radiative cooling
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Achieving serrated grain boundaries within gradient microstructures of nickel-based superalloys for dual-property turbine disks in aeroengines
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作者 Bingchao XIE Yongquan NING +4 位作者 Youwei LUO Zhaotian WANG Bowen SHI Mei ZHAN Mingwang FU 《Chinese Journal of Aeronautics》 2026年第2期641-660,共20页
Gradient microstructures strengthened by serrated Grain Boundaries(GBs)were achieved through a combination of Gradient Strain Deformation(GSD)and Serration Heat Treatment(SHT),with particular focus on microstructural ... Gradient microstructures strengthened by serrated Grain Boundaries(GBs)were achieved through a combination of Gradient Strain Deformation(GSD)and Serration Heat Treatment(SHT),with particular focus on microstructural evolution,underlying mechanisms,and the critical influencing factors.Dynamic recrystallization governed the microstructural evolution in the fine-grained and transition regions during GSD,where multiple nucleation mechanisms were active.Plastic deformation facilitated the dissolution ofγ'phase in fine-grained regions,ultimately resulting in its morphological transformation.During the subsequent SHT,serrated GBs formed within the gradient microstructures produced by prior GSD without disrupting the grain size gradient,thereby enhancing creep resistance.Two distinct mechanisms associated withγ'gbparticles governed the formation of the serrations at GBs.Owing to the stronger dragging effect of grain boundary junctions in fine-grained regions,the amplitude and wavelength of serrations in these regions were smaller than those in coarse-grained regions.Moreover,the formation of serrations exhibited a strong dependence on the inherent properties of the GBs.The random high-angle grain boundaries(HAGBs)with misorientation angles in the range of 30-59°tended to become serrated more easily during SHT due to their high mobility and the accelerated precipitation ofγ'gbparticles at them.Low-ΣHAGBs and low-angle GBs were not prone to form serrations.In particular,serration formation was completely inhibited atΣ3 twin boundaries due to their extremely low mobility and the absence ofγ'gbparticles. 展开更多
关键词 gradient microstructures Grain boundary migration Grain boundary properties Serrated grain boundaries Serration formation mechanisms SUPERALLOYS
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Gradient Descent-Based Prediction of Heat-Transmission Rate of Engine Oil-Based Hybrid Nanofluid over Trapezoidal and Rectangular Fins for Sustainable Energy Systems
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作者 Maddina Dinesh Kumar S.U.Mamatha +2 位作者 Khalid Masood Nehad Ali Shah Se-Jin Yook 《Computer Modeling in Engineering & Sciences》 2026年第1期627-660,共34页
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
关键词 Rectangular fin hybrid nanofluid trapezoidal fin angle of inclination gradient descent optimization Lobatto IIIa collocation method
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Examining the Nonlinear Effects of Urban Population Polycentricity on Carbon Emissions Efficiency Using a Gradient Boosting Decision Tree Model:Evidence from 295 Chinese Cities
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作者 WANG Cheng YANG Xingzhu 《Chinese Geographical Science》 2026年第2期222-238,共17页
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
关键词 urban polycentricity carbon emission efficiency gradient boosting decision tree(GBDT) nonlinear threshold effects Chinese cities
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双阶段特征优化:结合信号分解与HistGradientBoosting的故障分类
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作者 谷兵 李曦阳 +4 位作者 赵凯强 杨旭 王绍博 邢子龙 李晓欢 《机械设计与制造工程》 2026年第3期100-104,共5页
为提升电力设备轴承故障诊断精度,提出一种基于多域特征融合的智能诊断方法。首先采集调相机辅助设备轴承振动信号,采用改进的完备集合经验模态分解自适应噪声(ICEEMDAN)结合能量阈值进行分量重构,筛选有效成分;然后同步提取时域统计特... 为提升电力设备轴承故障诊断精度,提出一种基于多域特征融合的智能诊断方法。首先采集调相机辅助设备轴承振动信号,采用改进的完备集合经验模态分解自适应噪声(ICEEMDAN)结合能量阈值进行分量重构,筛选有效成分;然后同步提取时域统计特征、频域谱特征、小波包分解能量特征及非线性特征,构建高维特征集;最后采用基于直方图的梯度提升机(HistGradientBoosting)训练分类模型。在实测轴承数据集上的实验结果表明,该方法平均诊断准确率达96.7%,有效识别了健康状态及多种典型故障。研究验证了多域特征融合的有效性,为电力设备状态监测提供了可靠的技术方案。 展开更多
关键词 电力设备轴承 振动 改进的完备集合经验模态分解自适应噪声 故障诊断 调相机辅助设备 基于直方图的梯度提升机
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A Modified PRP-HS Hybrid Conjugate Gradient Algorithm for Solving Unconstrained Optimization Problems 被引量:1
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作者 LI Xiangli WANG Zhiling LI Binglan 《应用数学》 北大核心 2025年第2期553-564,共12页
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
关键词 Conjugate gradient method Unconstrained optimization Sufficient descent condition Global convergence
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Absorption-Reflection-Transmission Power Coefficient Guiding Gradient Distribution of Magnetic MXene in Layered Composites for Electromagnetic Wave Absorption 被引量:3
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作者 Yang Zhou Wen Zhang +7 位作者 Dong Pan Zhaoyang Li Bing Zhou Ming Huang Liwei Mi Chuntai Liu Yuezhan Feng Changyu Shen 《Nano-Micro Letters》 2025年第6期466-481,共16页
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
关键词 Magnetic MXene Layered and gradient structure Power coefficient Electromagnetic wave absorption
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CNN-ALSTM Soft-Sensing Model for Resistivity Gradient in CZ Monocrystalline Silicon Wafers 被引量:1
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作者 Zhiheng Zhang Zengguo Tian 《Instrumentation》 2025年第2期71-79,共9页
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
关键词 CZ monocrystalline silicon soft-sensing model CNN-ALSTM resistivity gradient
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Trends in alpha diversity,community composition,and network complexity of rare,intermediate,and abundant bacterial taxa along a latitudinal gradient and their impact on ecosystem multifunctionality 被引量:1
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作者 Rong Tang Shuaifeng Li +3 位作者 Xiaobo Huang Rui Zhang Cong Li Jianrong Su 《Forest Ecosystems》 2025年第4期642-654,共13页
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
关键词 BACTERIA Ecosystem multifunctionality Alpha diversity Community composition Network complexity Latitudinal gradient
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Advances in the Development of Gradient Scaffolds Made of Nano‑Micromaterials for Musculoskeletal Tissue Regeneration
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作者 Lei Fang Xiaoqi Lin +5 位作者 Ruian Xu Lu Liu Yu Zhang Feng Tian Jiao Jiao Li Jiajia Xue 《Nano-Micro Letters》 SCIE EI CAS 2025年第3期455-500,共46页
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
关键词 gradient scaffolds Musculoskeletal tissues Advanced manufacturing BIOMATERIALS Tissue regeneration
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The global lithospheric field modeling based on MSS-1 and other satellites' gradient data 被引量:1
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作者 YuXuan Lin Yan Feng +2 位作者 JiaXuan Zhang XinWu Li Ya Huang 《Earth and Planetary Physics》 2025年第3期677-685,共9页
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
关键词 lithospheric magnetic field Macao Science Satellite-1 gradient data LCS-1
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