In late May,the city of Dunhuang,a key historical hub of Eastern and Western cultures in Northwest China's Gansu Province,basked in clear and refreshing weather under a brilliant blue sky.The rugged Mingsha Mounta...In late May,the city of Dunhuang,a key historical hub of Eastern and Western cultures in Northwest China's Gansu Province,basked in clear and refreshing weather under a brilliant blue sky.The rugged Mingsha Mountain,renowned for the musical sounds produced by wind-blown sands when the wind blows,stood in silent majesty.To the close north of the mountain's massive golden dunes stood the city's international convention centre,where some 400 vips from 60 countries host cultural exchanges and mutual learning.展开更多
Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and mai...Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.展开更多
This study conducts a thorough examination of honeycomb sandwich panels with a lattice core,adopting advanced computational techniques for their modeling.The research extends its analysis to investigate the natural fr...This study conducts a thorough examination of honeycomb sandwich panels with a lattice core,adopting advanced computational techniques for their modeling.The research extends its analysis to investigate the natural frequency behavior of sandwich panels,encompassing the comprehensive assessment of the entire panel structure.At its core,the research applies the Representative Volume Element(RVE)theory to establish the equivalent material properties,thereby enhancing the predictive capabilities of lattice structure simulations.Themethodology applies these properties in the core of infinite panels,which are modeled using double periodic boundary conditions to explore their natural frequencies.Expanding beyond mere material characterization,the study introduces a novel approach to defining the material within the panel cores.By incorporating alternate materials such as steel and AlSiC,and by strategically modifying their ratios,the research streamlines the process of material variation without resorting to repetitive 3D operations on the constituent cells.This optimizes not only the computational resources but also offers insights into the structural response under diverse material compositions.Furthermore,the investigation extends its scope to analyze the influence of curvature on the structural behavior of lattice structures.Panels are modeled with varying degrees of curvature,ranging from single to double curvatures,including cylindrical and spherical configurations,across a spectrum of radii.A rigorous analysis is performed to study the effect of curvature on the mechanical performance and stability of lattice structures,offering valuable insights for design optimization and structural engineering applications.By building upon the existing knowledge and introducing innovative methodologies,this study contributes to improving the understanding of lattice structures and their applicability in diverse engineering contexts.展开更多
The correlation between the microstructure,properties,and strain partitioning behavior in a medium-carbon carbide-free bainitic steel was investigated through a combination of experiments and representative volume ele...The correlation between the microstructure,properties,and strain partitioning behavior in a medium-carbon carbide-free bainitic steel was investigated through a combination of experiments and representative volume element simulations.The results reveal that as the austempering temperature increases from low to intermediate,the optimal balance of properties shifts from strength-toughness to plasticity-toughness.The formation of fine bainitic ferrite plates and bainite sheaves under low austempering temperature(270℃)enhances both strength and toughness.Conversely,the wide size and shape distribution of the retained austenite(RA)obtained through austempering at intermediate temperature(350℃)contribute to increased work-hardening capacity,resulting in enhanced plasticity.The volume fraction of the ductile film-like RA plays a crucial role in enhancing impact toughness under relatively higher austempering temperatures.In the simulations of tensile deformation,the concentration of equivalent plastic strain predominantly manifests in the bainitic ferrite neighboring the martensite,whereas the equivalent plastic strain evenly spreads between the thin film-like retained austenite and bainitic ferrite.It is predicted that the cracks will occur at the interface between martensite and bainitic ferrite where the strain is concentrated,and eventually propagate along the strain failure zone.展开更多
In this paper,a two-stage light detection and ranging(LiDAR) three-dimensional(3D) object detection framework is presented,namely point-voxel dual transformer(PV-DT3D),which is a transformer-based method.In the propos...In this paper,a two-stage light detection and ranging(LiDAR) three-dimensional(3D) object detection framework is presented,namely point-voxel dual transformer(PV-DT3D),which is a transformer-based method.In the proposed PV-DT3D,point-voxel fusion features are used for proposal refinement.Specifically,keypoints are sampled from entire point cloud scene and used to encode representative scene features via a proposal-aware voxel set abstraction module.Subsequently,following the generation of proposals by the region proposal networks(RPN),the internal encoded keypoints are fed into the dual transformer encoder-decoder architecture.In 3D object detection,the proposed PV-DT3D takes advantage of both point-wise transformer and channel-wise architecture to capture contextual information from the spatial and channel dimensions.Experiments conducted on the highly competitive KITTI 3D car detection leaderboard show that the PV-DT3D achieves superior detection accuracy among state-of-the-art point-voxel-based methods.展开更多
304H austenitic stainless steel wire was investigated,emphasizing microstructural deformation,martensite phase transformation,and residual magnetic properties during drawing.Utilizing several microstructural observati...304H austenitic stainless steel wire was investigated,emphasizing microstructural deformation,martensite phase transformation,and residual magnetic properties during drawing.Utilizing several microstructural observation techniques,the volume fraction of martensite,modes of grain deformation in distinct regions,and the phase relationship between austenite and martensite were comprehensively characterized.In addition,a finite element simulation with representative volume elements specific to different zones also offers insights into strain responses during the drawing process.Results from the first-pass drawing reveal that there exists a higher volume fraction of martensite in the central region of 304H austenitic stainless steel wire compared to edge areas.This discrepancy is attributed to a concentrated presence of shear slip system{111}<110>γcrystallographic orientation,primarily accumulating in the central region obeying the Kurdjumov-Sachs path.Subsequent to the second drawing pass,the cumulative shear deformation within distinct regions of the steel wire became more pronounced.This resulted in a progressive augmentation of the volume fraction of martensite in both the central and peripheral regions of the steel wire.Concurrently,this led to a discernible elevation in the overall residual magnetism of the steel wire.展开更多
Different stress states have a significant influence on the magnitude of the microscopic plastic strain and result in the development of the microstructure evolution.As a result,a comprehensive understanding of the di...Different stress states have a significant influence on the magnitude of the microscopic plastic strain and result in the development of the microstructure evolution.As a result,a comprehensive understanding of the different scale variation on microstructure evolution during bending deformation is essential.The advanced high strength dual-phase(DP1180)steel was investigated using multiscale microstructure-based 3D representative volume element(RVE)modelling technology with emphasis on understanding the relationship between the microstructure,localised stress-strain evolution as well as the deformation characteristics in the bending process.It is demonstrated that the localised development in bending can be more accurately described by microscopic deformation when taking into account microstructural properties.Microstructure-based 3D RVEs from each chosen bending condition generally have comparable localisation properties,whilst the magnitudes and intensities differ.In addition,the most severe localised bands are predicted to occur close to the ferrite and martensite phase boundaries where the martensite grains are close together or have a somewhat sharp edge.The numerically predicted results for the microstructure evolution,shear bands development and stress and strain distribution after 3-point bending exhibit a good agreement with the relevant experimental observations.展开更多
The addition of nanoparticles serves as an effective reinforcement strategy for polymeric coatings,utilizing their unique characteristics as well as extraordinary mechanical,thermal,and electrical properties.The excep...The addition of nanoparticles serves as an effective reinforcement strategy for polymeric coatings,utilizing their unique characteristics as well as extraordinary mechanical,thermal,and electrical properties.The exceptionally high surface-to-volume ratio of nanoparticles imparts remarkable reinforcing potentials,yet it simultaneously gives rise to a prevalent tendency for nanoparticles to agglomerate into clusters within nanocomposites.The agglomeration behavior of the nanoparticles is predominantly influenced by their distinct microstructures and varied weight concentrations.This study investigated the synergistic effects of nanoparticle geometric shape and weight concentration on the dispersion characteristics of nanoparticles and the physical-mechanical performances of nano-reinforced epoxy coatings.Three carbon-based nanoparticles,nanodiamonds(NDs),carbon nanotubes(CNTs),and graphenes(GNPs),were incorporated into epoxy coatings at three weight concentrations(0.5%,1.0%,and 2.0%).The experimental findings reveal that epoxy coatings reinforced with NDs demonstrated the most homogenous dispersion characteristics,lowest viscosity,and reduced porosity among all the nanoparticles,which could be attributed to the spherical geometry shape.Due to the superior physical properties,ND-reinforced nanocomposites displayed the highest abrasion resistance and tensile properties.Specifically,the 1.0wt%ND-reinforced nanocomposites exhibited 60%,52%,and 97%improvements in mass lost,tensile strength,and failure strain,respectively,compared to pure epoxy.Furthermore,the representative volume element(RVE)modeling was employed to validate the experimental results,while highlighting the critical role of nanoparticle agglomeration,orientation,and the presence of voids on the mechanical properties of the nanocomposites.Nano-reinforced epoxy coatings with enhanced mechanical properties are well-suited for application in protective coatings for pipelines,industrial equipment,and automotive parts,where high wear resistance is essential.展开更多
Rechargeable zinc-air batteries(ZABs) have recently drawn great attention in energy research due to their high theoretical capacity,low costs, and inherently safe nature [1–3]. However, the sluggish cathode reactions...Rechargeable zinc-air batteries(ZABs) have recently drawn great attention in energy research due to their high theoretical capacity,low costs, and inherently safe nature [1–3]. However, the sluggish cathode reactions necessitate the development of bifunctional oxygen electrocatalysts with lower ΔE indicator values. The ΔE indicator is commonly employed to quantitatively evaluate the electrocatalytic activity of a bifunctional oxygen electrocatalyst,representing the overall overpotential from oxygen reduction reaction(ORR) to oxygen evolution reaction(OER).展开更多
The first plenary meeting of ISO/TC 8/SC 27,Ports and terminals,was held on October 21 in Shanghai,which attracted representatives from 15 member states and 5 international organizations,as well as over 100 experts an...The first plenary meeting of ISO/TC 8/SC 27,Ports and terminals,was held on October 21 in Shanghai,which attracted representatives from 15 member states and 5 international organizations,as well as over 100 experts and scholars.展开更多
Agroup of young representatives and scholars from more than 10 foreign countries had great fun collecting water samples from the Grand Canal in Sanwan Park,Yangzhou City,east China’s Jiangsu Province,on June 3,2025.T...Agroup of young representatives and scholars from more than 10 foreign countries had great fun collecting water samples from the Grand Canal in Sanwan Park,Yangzhou City,east China’s Jiangsu Province,on June 3,2025.The samples were poured into a“pot of civilization,”which symbolized the integration of cultures.In addition to the canal,the young people also visited places such as Yangzhou University,China Grand Canal Museum,and the Slender West Lake,learning the culture of the Grand Canal and the canal city of Yangzhou.展开更多
China’s economy reached its 2024 growth target despite a complex domestic and global landscape,providing much needed certainty and confidence to the global economy.The annual Gross Domestic Product(GDP)reached RMB 13...China’s economy reached its 2024 growth target despite a complex domestic and global landscape,providing much needed certainty and confidence to the global economy.The annual Gross Domestic Product(GDP)reached RMB 13,490.84 billion,representing a 5.0%increase over the previous year in constant prices.By sector,the added value of the primary sector was RMB 914.14 billion,up by 3.5%year-on year;the secondary sector’s added value was RMB 4,920.87 billion,up by 5.3%;and the tertiary sector’s added value was RMB 7,655.83 billion,up by 5.0%.展开更多
High-pressure synthesis of lutetium hydrides from molecular hydrogen(H_(2))and lutetium(Lu)is systematically investigated using synchrotron X-ray diffraction,Raman spectroscopy,and visual observations.We demonstrate t...High-pressure synthesis of lutetium hydrides from molecular hydrogen(H_(2))and lutetium(Lu)is systematically investigated using synchrotron X-ray diffraction,Raman spectroscopy,and visual observations.We demonstrate that the reaction pathway between H_(2)and Lu invariably follows the sequence Lu→LuH_(2)→LuH_(3)and exhibits a notable time dependence.A comprehensive diagram representing the formation and synthesis of lutetium hydrides as a function of pressure and time is constructed.Our findings indicate that the synthesis can be accelerated by elevated temperature and decelerated by increased pressure.Notably,two critical pressure thresholds at ambient temperature are identified:the synthesis of LuH_(2)from Lu commences at a minimum pressure of~3 GPa,while~28 GPa is the minimum pressure at which LuH_(2)fails to transform into LuH_(3)within a time scale of months.This underscores the significant impact of temporal factors on synthesis,with the reaction completion time increasing sub-linearly with rising pressure.Furthermore,the cubic phase of LuH_(3)can be obtained exclusively through compressing the trigonal LuH_(3)phase at~11.5 GPa.We also demonstrate that the bandgap of LuH_(3)slowly closes under pressure and is noticeably lower than that of LuH_(2).展开更多
Cardiovascular disease(CVD)represents the foremost cause of mortality globally,imposing a substantial economic burden.In 2021,approximately 19.4 million deaths were attributed to cardiovascular conditions,constituting...Cardiovascular disease(CVD)represents the foremost cause of mortality globally,imposing a substantial economic burden.In 2021,approximately 19.4 million deaths were attributed to cardiovascular conditions,constituting 32%of global mortality[1].Over three-quarters of these fatalities occurred in low and middle-income nations.Notably,ischemic heart disease and stroke were responsible for 84%of CVD-related deaths.Among them,the number of cases of ischemic cardiomyopathy increased by 68%in 2021 compared to 1990(Figure 1A).展开更多
The investigation of whether sediment samples contain representative grain size distribution information is important for the accurate extraction of sediment characteristics and conduct of related sedimentary record s...The investigation of whether sediment samples contain representative grain size distribution information is important for the accurate extraction of sediment characteristics and conduct of related sedimentary record studies.This study comparatively analyzed the numerical and qualitative differences and the degree of correlation of 36 sets of the characteristic parameters of surface sediment parallel sample grain size distribution from three sampling profiles at Jinsha Bay Beach in Zhanjiang,western Guangdong.At each sampling point,five parallel subsamples were established at intervals of 0,10,20,50,and 100 cm along the coastline.The research findings indicate the following:1)relatively large differences in the mean values of the different parallel samples(0.19–0.34Φ),with smaller differences observed in other characteristic grain sizes(D_(10),D_(50),and D_(90));2)small differences in characteristic values among various parallel sample grain size parameters,with at least 33%of the combinations of qualitative results showing inconsistency;3)50%of the regression equations between the skewness of different parallel samples displaying no significant correlation;4)relative deviations of−47.91%to 27.63%and−49.20%to 2.08%existing between the particle size parameters of a single sample and parallel samples(with the average obtained)at intervals of 10 and 50 cm,respectively.As such,small spatial differences,even within 100 cm,can considerably affect grain size parameters.Given the uncertain reasons underlying the representativeness of the samples,which may only cover the area immediately surrounding the sampling station,researchers are advised to design parallel sample collection strategies based on the spatiotemporal distribution characteristics of the parameters of interest during sediment sample collection.This study provides a typical case of the comparative analysis of parallel sample grain size parameters,with a focus on small spatial beach sediment,which contributes to the enhanced understanding of the accuracy and reliability of sediment sample collection strategies and extraction of grain size information.展开更多
Hypertrophic cardiomyopathy(HCM)is a primary myocardial disease characterized by myocardial hypertrophy,excluding other cardiovascular or systemic/metabolic causes of ventricular wall thickening.Apical hypertrophic ca...Hypertrophic cardiomyopathy(HCM)is a primary myocardial disease characterized by myocardial hypertrophy,excluding other cardiovascular or systemic/metabolic causes of ventricular wall thickening.Apical hypertrophic cardiomyopathy(ApHCM)represents a special form of ventricular hypertrophy predominantly affecting the left ventricular apex below the papillary muscles,typically without significant left ventricular outflow tract obstruction.[1,2]ApHCM often coexists with mild coronary artery abnormalities,[3]and reports of acute myocardial infarction with coronary artery stenosis in ApHCM or HCM patients are uncommon.展开更多
An annual event in March in China is the Two Sessions,the meetings of the National People’s Congress(NPC)and the National Committee of the Chinese People’s Political Consultative Conference(CPPCC).The SPOTLIGHT colu...An annual event in March in China is the Two Sessions,the meetings of the National People’s Congress(NPC)and the National Committee of the Chinese People’s Political Consultative Conference(CPPCC).The SPOTLIGHT column of the issue displays the speech highlights of Luo Wen,SAMR Minister,and the insights into standards of representatives during the meetings.展开更多
Slope reliability analysis considering inherent spatial variability(ISV)of soil properties is timeconsuming when response surface method(RSM)is used,because of the"curse of dimensionality".This paper propose...Slope reliability analysis considering inherent spatial variability(ISV)of soil properties is timeconsuming when response surface method(RSM)is used,because of the"curse of dimensionality".This paper proposes an effective method for identification of representative slip surfaces(RSSs)of slopes with spatially varied soils within the framework of limit equilibrium method(LEM),which utilizes an adaptive K-means clustering approach.Then,an improved slope reliability analysis based on the RSSs and RSM considering soil spatial variability,in perspective of computation efficiency,is established.The detailed implementation procedure of the proposed method is well documented,and the ability of the method in identifying RSSs and estimating reliability is investigated via three slope examples.Results show that the proposed method can automatically identify the RSSs of slope with only one evaluation of the conventional deterministic slope stability model.The RSSs are invariant with the statistics of soil properties,which allows parametric studies that are often required in slope reliability analysis to be efficiently achieved with ease.It is also found that the proposed method provides comparable values of factor of safety(FS)and probability of failure(Pf)of slopes with those obtained from direct analysis and lite rature.展开更多
The experiments were conducted for three consecutive years across 14 locations using 9 non-waxy proso millet genotypes and 16 locations using 7 waxy proso millet genotypes in China. The objectives of this study were t...The experiments were conducted for three consecutive years across 14 locations using 9 non-waxy proso millet genotypes and 16 locations using 7 waxy proso millet genotypes in China. The objectives of this study were to analyze yield stability and adaptability of proso millets and to evaluate the discrimination and representativeness of locations by analysis of vari- ance （ANOVA） and genotype and genotype by environment interaction （GGE） biplot methods. Grain yields of proso millet genotypes were significantly influenced by environment （E）, genotype （G） and their interaction （GxE） （P〈0.1%）. GxE inter- action effect was six times higher than G effect in non-waxy group and seven times in waxy group. N04-339 in non-waxy and Neimi 6 （NM6） in waxy showed higher grain yields and stability compared with other genotypes. Also, Neimi 9 （NM9, a non-waxy cultivar） and 90322-2-33 （a waxy cultivar） showed higher adaptability in 7 and in 11 locations, respectively. For non-waxy, Dalat, Inner Mongolia （E2） and Wuzhai, Shanxi （E5） were the best sites among all the locations for maximizing the variance among candidate cultivars, and Yanchi, Ningxia （El0） had the best representativeness. Wuzhai, Shanxi （e9） and Yanchi, Ningxia （e14） were the best representative locations, and Baicheng, Jilin （e2） was better discriminating location than others for waxy genotypes. Based on our results, El0 and e14 have enhanced efficiency and accuracy for non-waxy genotypes and waxy genotypes selection, respectively in national regional test of proso millet varieties.展开更多
Cracks resulting from cyclic wetting and drying of expansive soils create discontinuities and anisotropy in the soil.The representative elementary volume(REV)defined by the continuous-media theory cannot be applied to...Cracks resulting from cyclic wetting and drying of expansive soils create discontinuities and anisotropy in the soil.The representative elementary volume(REV)defined by the continuous-media theory cannot be applied to cracked expansive soils that are considered discontinuous media.In this study,direct shear tests of three different scales(30 cm^(2),900 cm^(2),1963 cm^(2))and crack image analysis were carried out on undisturbed soil samples subjected to drying-wetting cycles in-situ.The REV size of expansive soil was investigated using the crack intensity factor(CIF)and soil cohesion.The results show that soil cohesion decreased with increasing sample area,and the development of secondary cracks further exacerbated the size effect of sample on cohesion of the soil.As shrinkage cracks developed,the REV size of the soil gradually increased and plateaued after 3−5 cycles.Under the same drying-wetting cycle conditions,the REV size determined using soil cohesion(REV-C)is 1.75 to 2.97 times the REV size determined using CIF(REV-CIF).Under the influence of shrinkage cracks,the average CIF is positively correlated with the REV size determined using different maximum permissible errors,with the coefficient of correlation greater than 0.9.A method for determining the REV-C based on crack image analysis is proposed,and the REV-C of expansive soil in the study area under different exposure times is given.展开更多
文摘In late May,the city of Dunhuang,a key historical hub of Eastern and Western cultures in Northwest China's Gansu Province,basked in clear and refreshing weather under a brilliant blue sky.The rugged Mingsha Mountain,renowned for the musical sounds produced by wind-blown sands when the wind blows,stood in silent majesty.To the close north of the mountain's massive golden dunes stood the city's international convention centre,where some 400 vips from 60 countries host cultural exchanges and mutual learning.
基金Project(2017G006-N)supported by the Project of Science and Technology Research and Development Program of China Railway Corporation。
文摘Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.
文摘This study conducts a thorough examination of honeycomb sandwich panels with a lattice core,adopting advanced computational techniques for their modeling.The research extends its analysis to investigate the natural frequency behavior of sandwich panels,encompassing the comprehensive assessment of the entire panel structure.At its core,the research applies the Representative Volume Element(RVE)theory to establish the equivalent material properties,thereby enhancing the predictive capabilities of lattice structure simulations.Themethodology applies these properties in the core of infinite panels,which are modeled using double periodic boundary conditions to explore their natural frequencies.Expanding beyond mere material characterization,the study introduces a novel approach to defining the material within the panel cores.By incorporating alternate materials such as steel and AlSiC,and by strategically modifying their ratios,the research streamlines the process of material variation without resorting to repetitive 3D operations on the constituent cells.This optimizes not only the computational resources but also offers insights into the structural response under diverse material compositions.Furthermore,the investigation extends its scope to analyze the influence of curvature on the structural behavior of lattice structures.Panels are modeled with varying degrees of curvature,ranging from single to double curvatures,including cylindrical and spherical configurations,across a spectrum of radii.A rigorous analysis is performed to study the effect of curvature on the mechanical performance and stability of lattice structures,offering valuable insights for design optimization and structural engineering applications.By building upon the existing knowledge and introducing innovative methodologies,this study contributes to improving the understanding of lattice structures and their applicability in diverse engineering contexts.
基金supported by the National Key R&D Program Young Scientists Project(2021YFB3703500)National Natural Science Foundation of China(52001110,52122410,52374406),S&T Program of Hebei(23311004D)+1 种基金Natural Science Foundation of Hebei Province(E2023203259)Science and Technology Project of Yantai(2022ZDCX002).
文摘The correlation between the microstructure,properties,and strain partitioning behavior in a medium-carbon carbide-free bainitic steel was investigated through a combination of experiments and representative volume element simulations.The results reveal that as the austempering temperature increases from low to intermediate,the optimal balance of properties shifts from strength-toughness to plasticity-toughness.The formation of fine bainitic ferrite plates and bainite sheaves under low austempering temperature(270℃)enhances both strength and toughness.Conversely,the wide size and shape distribution of the retained austenite(RA)obtained through austempering at intermediate temperature(350℃)contribute to increased work-hardening capacity,resulting in enhanced plasticity.The volume fraction of the ductile film-like RA plays a crucial role in enhancing impact toughness under relatively higher austempering temperatures.In the simulations of tensile deformation,the concentration of equivalent plastic strain predominantly manifests in the bainitic ferrite neighboring the martensite,whereas the equivalent plastic strain evenly spreads between the thin film-like retained austenite and bainitic ferrite.It is predicted that the cracks will occur at the interface between martensite and bainitic ferrite where the strain is concentrated,and eventually propagate along the strain failure zone.
基金supported by the Natural Science Foundation of China (No.62103298)the South African National Research Foundation (Nos.132797 and 137951)。
文摘In this paper,a two-stage light detection and ranging(LiDAR) three-dimensional(3D) object detection framework is presented,namely point-voxel dual transformer(PV-DT3D),which is a transformer-based method.In the proposed PV-DT3D,point-voxel fusion features are used for proposal refinement.Specifically,keypoints are sampled from entire point cloud scene and used to encode representative scene features via a proposal-aware voxel set abstraction module.Subsequently,following the generation of proposals by the region proposal networks(RPN),the internal encoded keypoints are fed into the dual transformer encoder-decoder architecture.In 3D object detection,the proposed PV-DT3D takes advantage of both point-wise transformer and channel-wise architecture to capture contextual information from the spatial and channel dimensions.Experiments conducted on the highly competitive KITTI 3D car detection leaderboard show that the PV-DT3D achieves superior detection accuracy among state-of-the-art point-voxel-based methods.
基金funded by National Natural Science Foundation of China(52201084 and 52231003)Major Program(JD)of Hubei Province(2023BAA019)+2 种基金China Scholarship Council(CSC)Postdoctoral Station of metallurgical Engineering of Wuhan University of Science and Technology(WUST)Postdoctoral workstation of Zhejiang Jincheng New Material Co.,Ltd.
文摘304H austenitic stainless steel wire was investigated,emphasizing microstructural deformation,martensite phase transformation,and residual magnetic properties during drawing.Utilizing several microstructural observation techniques,the volume fraction of martensite,modes of grain deformation in distinct regions,and the phase relationship between austenite and martensite were comprehensively characterized.In addition,a finite element simulation with representative volume elements specific to different zones also offers insights into strain responses during the drawing process.Results from the first-pass drawing reveal that there exists a higher volume fraction of martensite in the central region of 304H austenitic stainless steel wire compared to edge areas.This discrepancy is attributed to a concentrated presence of shear slip system{111}<110>γcrystallographic orientation,primarily accumulating in the central region obeying the Kurdjumov-Sachs path.Subsequent to the second drawing pass,the cumulative shear deformation within distinct regions of the steel wire became more pronounced.This resulted in a progressive augmentation of the volume fraction of martensite in both the central and peripheral regions of the steel wire.Concurrently,this led to a discernible elevation in the overall residual magnetism of the steel wire.
基金supported by HBIS Group under the Grant No.IRIS 200506003.
文摘Different stress states have a significant influence on the magnitude of the microscopic plastic strain and result in the development of the microstructure evolution.As a result,a comprehensive understanding of the different scale variation on microstructure evolution during bending deformation is essential.The advanced high strength dual-phase(DP1180)steel was investigated using multiscale microstructure-based 3D representative volume element(RVE)modelling technology with emphasis on understanding the relationship between the microstructure,localised stress-strain evolution as well as the deformation characteristics in the bending process.It is demonstrated that the localised development in bending can be more accurately described by microscopic deformation when taking into account microstructural properties.Microstructure-based 3D RVEs from each chosen bending condition generally have comparable localisation properties,whilst the magnitudes and intensities differ.In addition,the most severe localised bands are predicted to occur close to the ferrite and martensite phase boundaries where the martensite grains are close together or have a somewhat sharp edge.The numerically predicted results for the microstructure evolution,shear bands development and stress and strain distribution after 3-point bending exhibit a good agreement with the relevant experimental observations.
基金supported by the National Science Foundation(NSF)(No.CMMI-1750316)Pipeline and Hazardous Materials Safety Administration(PHMSA)of U.S.Department of Transportation(No.693JK31950008CAAP).
文摘The addition of nanoparticles serves as an effective reinforcement strategy for polymeric coatings,utilizing their unique characteristics as well as extraordinary mechanical,thermal,and electrical properties.The exceptionally high surface-to-volume ratio of nanoparticles imparts remarkable reinforcing potentials,yet it simultaneously gives rise to a prevalent tendency for nanoparticles to agglomerate into clusters within nanocomposites.The agglomeration behavior of the nanoparticles is predominantly influenced by their distinct microstructures and varied weight concentrations.This study investigated the synergistic effects of nanoparticle geometric shape and weight concentration on the dispersion characteristics of nanoparticles and the physical-mechanical performances of nano-reinforced epoxy coatings.Three carbon-based nanoparticles,nanodiamonds(NDs),carbon nanotubes(CNTs),and graphenes(GNPs),were incorporated into epoxy coatings at three weight concentrations(0.5%,1.0%,and 2.0%).The experimental findings reveal that epoxy coatings reinforced with NDs demonstrated the most homogenous dispersion characteristics,lowest viscosity,and reduced porosity among all the nanoparticles,which could be attributed to the spherical geometry shape.Due to the superior physical properties,ND-reinforced nanocomposites displayed the highest abrasion resistance and tensile properties.Specifically,the 1.0wt%ND-reinforced nanocomposites exhibited 60%,52%,and 97%improvements in mass lost,tensile strength,and failure strain,respectively,compared to pure epoxy.Furthermore,the representative volume element(RVE)modeling was employed to validate the experimental results,while highlighting the critical role of nanoparticle agglomeration,orientation,and the presence of voids on the mechanical properties of the nanocomposites.Nano-reinforced epoxy coatings with enhanced mechanical properties are well-suited for application in protective coatings for pipelines,industrial equipment,and automotive parts,where high wear resistance is essential.
基金National Research Foundation (NRF Investigatorship NRF-NRFI09-0002)Agency for Science,Technology and Research (MTC Programmatic Fund M23L9b0052)。
文摘Rechargeable zinc-air batteries(ZABs) have recently drawn great attention in energy research due to their high theoretical capacity,low costs, and inherently safe nature [1–3]. However, the sluggish cathode reactions necessitate the development of bifunctional oxygen electrocatalysts with lower ΔE indicator values. The ΔE indicator is commonly employed to quantitatively evaluate the electrocatalytic activity of a bifunctional oxygen electrocatalyst,representing the overall overpotential from oxygen reduction reaction(ORR) to oxygen evolution reaction(OER).
文摘The first plenary meeting of ISO/TC 8/SC 27,Ports and terminals,was held on October 21 in Shanghai,which attracted representatives from 15 member states and 5 international organizations,as well as over 100 experts and scholars.
文摘Agroup of young representatives and scholars from more than 10 foreign countries had great fun collecting water samples from the Grand Canal in Sanwan Park,Yangzhou City,east China’s Jiangsu Province,on June 3,2025.The samples were poured into a“pot of civilization,”which symbolized the integration of cultures.In addition to the canal,the young people also visited places such as Yangzhou University,China Grand Canal Museum,and the Slender West Lake,learning the culture of the Grand Canal and the canal city of Yangzhou.
文摘China’s economy reached its 2024 growth target despite a complex domestic and global landscape,providing much needed certainty and confidence to the global economy.The annual Gross Domestic Product(GDP)reached RMB 13,490.84 billion,representing a 5.0%increase over the previous year in constant prices.By sector,the added value of the primary sector was RMB 914.14 billion,up by 3.5%year-on year;the secondary sector’s added value was RMB 4,920.87 billion,up by 5.3%;and the tertiary sector’s added value was RMB 7,655.83 billion,up by 5.0%.
基金supported by research grants of the Youth Innovation Promotion Association of CAS(Grant No.2021446)the National Science Foundation of China(Grant Nos.12204484,51672279,12174398 and 11874361)+1 种基金the Anhui Key Research and Development Program(Grant No.2022h11020007)the HFIPS Director’s Fund of the Chinese Academy of Sciences(Grant Nos.BJPY2022B02,YZJJ202102,YZJJ-GGZX-2022-01,and 2021YZGH03).
文摘High-pressure synthesis of lutetium hydrides from molecular hydrogen(H_(2))and lutetium(Lu)is systematically investigated using synchrotron X-ray diffraction,Raman spectroscopy,and visual observations.We demonstrate that the reaction pathway between H_(2)and Lu invariably follows the sequence Lu→LuH_(2)→LuH_(3)and exhibits a notable time dependence.A comprehensive diagram representing the formation and synthesis of lutetium hydrides as a function of pressure and time is constructed.Our findings indicate that the synthesis can be accelerated by elevated temperature and decelerated by increased pressure.Notably,two critical pressure thresholds at ambient temperature are identified:the synthesis of LuH_(2)from Lu commences at a minimum pressure of~3 GPa,while~28 GPa is the minimum pressure at which LuH_(2)fails to transform into LuH_(3)within a time scale of months.This underscores the significant impact of temporal factors on synthesis,with the reaction completion time increasing sub-linearly with rising pressure.Furthermore,the cubic phase of LuH_(3)can be obtained exclusively through compressing the trigonal LuH_(3)phase at~11.5 GPa.We also demonstrate that the bandgap of LuH_(3)slowly closes under pressure and is noticeably lower than that of LuH_(2).
基金supported by the National Natural Science Foundation of China(No.82270364)Science and Technology Program of Guizhou Province(No.ZK[2023]321)+3 种基金Guizhou Provincial Youth Science and Technology Talents Growth Project(No.KY[2022]214)Excellent Young Talents Plan of Guizhou Medical University(No.[2023]112)Guizhou Medical University Key Laboratory of Cardiovascular Disease Basic and Clinical Research(No.2024001)Start-up Fund of Guizhou Medical University(No.J2021032).
文摘Cardiovascular disease(CVD)represents the foremost cause of mortality globally,imposing a substantial economic burden.In 2021,approximately 19.4 million deaths were attributed to cardiovascular conditions,constituting 32%of global mortality[1].Over three-quarters of these fatalities occurred in low and middle-income nations.Notably,ischemic heart disease and stroke were responsible for 84%of CVD-related deaths.Among them,the number of cases of ischemic cardiomyopathy increased by 68%in 2021 compared to 1990(Figure 1A).
基金supported by the Innovation Driven Development Foundation of Guangxi(No.AD22080035)the Open Project Funding of the Key Laboratory of Tropical Marine Ecosystem and Bioresource,Ministry of Natural Resources(No.2023-QN04)+1 种基金the Guangdong Provincial Ordinary University Youth Innovative Talent Project in 2024(No.2024KQNCX134)the Guangdong Provincial Special Fund Project for Talent Development Strategy in 2024(No.2024R3005).
文摘The investigation of whether sediment samples contain representative grain size distribution information is important for the accurate extraction of sediment characteristics and conduct of related sedimentary record studies.This study comparatively analyzed the numerical and qualitative differences and the degree of correlation of 36 sets of the characteristic parameters of surface sediment parallel sample grain size distribution from three sampling profiles at Jinsha Bay Beach in Zhanjiang,western Guangdong.At each sampling point,five parallel subsamples were established at intervals of 0,10,20,50,and 100 cm along the coastline.The research findings indicate the following:1)relatively large differences in the mean values of the different parallel samples(0.19–0.34Φ),with smaller differences observed in other characteristic grain sizes(D_(10),D_(50),and D_(90));2)small differences in characteristic values among various parallel sample grain size parameters,with at least 33%of the combinations of qualitative results showing inconsistency;3)50%of the regression equations between the skewness of different parallel samples displaying no significant correlation;4)relative deviations of−47.91%to 27.63%and−49.20%to 2.08%existing between the particle size parameters of a single sample and parallel samples(with the average obtained)at intervals of 10 and 50 cm,respectively.As such,small spatial differences,even within 100 cm,can considerably affect grain size parameters.Given the uncertain reasons underlying the representativeness of the samples,which may only cover the area immediately surrounding the sampling station,researchers are advised to design parallel sample collection strategies based on the spatiotemporal distribution characteristics of the parameters of interest during sediment sample collection.This study provides a typical case of the comparative analysis of parallel sample grain size parameters,with a focus on small spatial beach sediment,which contributes to the enhanced understanding of the accuracy and reliability of sediment sample collection strategies and extraction of grain size information.
文摘Hypertrophic cardiomyopathy(HCM)is a primary myocardial disease characterized by myocardial hypertrophy,excluding other cardiovascular or systemic/metabolic causes of ventricular wall thickening.Apical hypertrophic cardiomyopathy(ApHCM)represents a special form of ventricular hypertrophy predominantly affecting the left ventricular apex below the papillary muscles,typically without significant left ventricular outflow tract obstruction.[1,2]ApHCM often coexists with mild coronary artery abnormalities,[3]and reports of acute myocardial infarction with coronary artery stenosis in ApHCM or HCM patients are uncommon.
文摘An annual event in March in China is the Two Sessions,the meetings of the National People’s Congress(NPC)and the National Committee of the Chinese People’s Political Consultative Conference(CPPCC).The SPOTLIGHT column of the issue displays the speech highlights of Luo Wen,SAMR Minister,and the insights into standards of representatives during the meetings.
基金The work described in this paper was nancially supported by the Natural Science Foundation of China(Grant Nos.51709258,51979270 and 41902291),the CAS Pioneer Hundred Talents Pro-gram and the Research Foundation of Key Laboratory of Deep Geodrilling Technology,Ministry of Land and Resources,China(Grant No.F201801).
文摘Slope reliability analysis considering inherent spatial variability(ISV)of soil properties is timeconsuming when response surface method(RSM)is used,because of the"curse of dimensionality".This paper proposes an effective method for identification of representative slip surfaces(RSSs)of slopes with spatially varied soils within the framework of limit equilibrium method(LEM),which utilizes an adaptive K-means clustering approach.Then,an improved slope reliability analysis based on the RSSs and RSM considering soil spatial variability,in perspective of computation efficiency,is established.The detailed implementation procedure of the proposed method is well documented,and the ability of the method in identifying RSSs and estimating reliability is investigated via three slope examples.Results show that the proposed method can automatically identify the RSSs of slope with only one evaluation of the conventional deterministic slope stability model.The RSSs are invariant with the statistics of soil properties,which allows parametric studies that are often required in slope reliability analysis to be efficiently achieved with ease.It is also found that the proposed method provides comparable values of factor of safety(FS)and probability of failure(Pf)of slopes with those obtained from direct analysis and lite rature.
基金funded by the National Key Technologies R&D Program of China during the 12th Five-Year Plan period (2014BAD07B03)the National Natural Science Foundation of China (31371529)+2 种基金the Postdoctoral Science Foundation of Heilongjiang Province, China (LBH-Z14177)the project of Education Department in Heilongjiang Province, China (12541599)the China Agricultural Research System (CARS07-13.5-A9)
文摘The experiments were conducted for three consecutive years across 14 locations using 9 non-waxy proso millet genotypes and 16 locations using 7 waxy proso millet genotypes in China. The objectives of this study were to analyze yield stability and adaptability of proso millets and to evaluate the discrimination and representativeness of locations by analysis of vari- ance （ANOVA） and genotype and genotype by environment interaction （GGE） biplot methods. Grain yields of proso millet genotypes were significantly influenced by environment （E）, genotype （G） and their interaction （GxE） （P〈0.1%）. GxE inter- action effect was six times higher than G effect in non-waxy group and seven times in waxy group. N04-339 in non-waxy and Neimi 6 （NM6） in waxy showed higher grain yields and stability compared with other genotypes. Also, Neimi 9 （NM9, a non-waxy cultivar） and 90322-2-33 （a waxy cultivar） showed higher adaptability in 7 and in 11 locations, respectively. For non-waxy, Dalat, Inner Mongolia （E2） and Wuzhai, Shanxi （E5） were the best sites among all the locations for maximizing the variance among candidate cultivars, and Yanchi, Ningxia （El0） had the best representativeness. Wuzhai, Shanxi （e9） and Yanchi, Ningxia （e14） were the best representative locations, and Baicheng, Jilin （e2） was better discriminating location than others for waxy genotypes. Based on our results, El0 and e14 have enhanced efficiency and accuracy for non-waxy genotypes and waxy genotypes selection, respectively in national regional test of proso millet varieties.
基金Project(41472240)supported by the National Natural Science Foundation of ChinaProjects(2015B25514,2015B17214)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Cracks resulting from cyclic wetting and drying of expansive soils create discontinuities and anisotropy in the soil.The representative elementary volume(REV)defined by the continuous-media theory cannot be applied to cracked expansive soils that are considered discontinuous media.In this study,direct shear tests of three different scales(30 cm^(2),900 cm^(2),1963 cm^(2))and crack image analysis were carried out on undisturbed soil samples subjected to drying-wetting cycles in-situ.The REV size of expansive soil was investigated using the crack intensity factor(CIF)and soil cohesion.The results show that soil cohesion decreased with increasing sample area,and the development of secondary cracks further exacerbated the size effect of sample on cohesion of the soil.As shrinkage cracks developed,the REV size of the soil gradually increased and plateaued after 3−5 cycles.Under the same drying-wetting cycle conditions,the REV size determined using soil cohesion(REV-C)is 1.75 to 2.97 times the REV size determined using CIF(REV-CIF).Under the influence of shrinkage cracks,the average CIF is positively correlated with the REV size determined using different maximum permissible errors,with the coefficient of correlation greater than 0.9.A method for determining the REV-C based on crack image analysis is proposed,and the REV-C of expansive soil in the study area under different exposure times is given.
