It is well known that coarse-grained super-elastic NiTi shape memory alloys(SMAs)exhibit localized rather than homogeneous martensite transformation(MT),which,however,can be strongly influenced by either internal size...It is well known that coarse-grained super-elastic NiTi shape memory alloys(SMAs)exhibit localized rather than homogeneous martensite transformation(MT),which,however,can be strongly influenced by either internal size(grain size,GS)or the external size(geometric size).The coupled effect of GS and geometric size on the functional properties has not been clearly understood yet.In this work,the super-elasticity,one-way,and stress-assisted two-way shape memory effects of the polycrystalline NiTi SMAs with different aspect ratios(length/width for the gauge section)and different GSs are investigated based on the phase field method.The coupled effect of the aspect ratio and GS on the functional properties is adequately revealed.The simulated results indicate that when the aspect ratio is lower than about 4:1,the stress biaxiality and stress heterogeneity in the gauge section of the sample become more and more obvious with decreasing the aspect ratio,which can significantly influence the microstructure evolution in the process involving external stress.Therefore,the corresponding functional property is strongly dependent on the aspect ratio.With decreasing the GS and the aspect ratio(to be lower than 4:1),both the aspect ratio and GS can affect the MT or martensite reorientation in each grain and the interaction among grains.Thus,due to the strong internal constraint(i.e.,the constraint of grain boundary)and the external constraint(i.e.,the constraint of geometric boundary),the capabilities of the functional properties of NiTi SMAs are gradually weakened and highly dependent on these two factors.展开更多
Background:The rate of distant metastasis in patients with pancreatic neuroendocrine tumors(PNETs)is20%-50%at the time of initial diagnosis.However,whether tumor size can predict distant metastasis for PNETs remains u...Background:The rate of distant metastasis in patients with pancreatic neuroendocrine tumors(PNETs)is20%-50%at the time of initial diagnosis.However,whether tumor size can predict distant metastasis for PNETs remains unknown up to date.Methods:We used Surveillance,Epidemiology,and End Results(SEER)population-based data to collect6089 patients with PNETs from 2010 to 2019.The optimal cut-off point of tumor size to predict distant metastasis was calculated by Youden’s index.Multivariate logistic regression analysis was used to figure out the association between tumor size and distant metastasis patterns.Results:The most common metastatic site was liver(27.2%),followed by bone(3.0%),lung(2.3%)and brain(0.4%).Based on an optimal cut-off value of tumor size(25.5 mm)for predicting distant metastasis determined by Youden’s index,patients were categorized into groups of tumor size<25.5 mm and≥25.5 mm.Multivariate logistic regression analyses showed that,compared with<25.5 mm,tumor size≥25.5 mm was an independent risk predictor of overall distant metastasis[odds ratio(OR)=4.491,95%confidence interval(CI):3.724-5.416,P<0.001]and liver metastasis(OR=4.686,95%CI:3.886-5.651,P<0.001).Conclusions:Tumor size≥25.5 mm was significantly associated with more overall distant and liver metastases.Timely identification of distant metastasis for tumor size≥25.5 mm may provide survival benefit for timely and precise treatment.展开更多
In ball milling,the process parameters are decisive in influencing the quality and performance of the final ball-milled product,and crucial but often neglected is the ratio of the grinding balls in terms of their size...In ball milling,the process parameters are decisive in influencing the quality and performance of the final ball-milled product,and crucial but often neglected is the ratio of the grinding balls in terms of their size.Here,for a given number of large grinding balls,the ratio of large to small ones is set to 1:2,1:3,1:4,and 1:5 by altering the number of small ones,and how this affects the morphology,structure,and electrochemical properties of ball-milled graphene nanosheets is investigated.The results show that changing the ball ratio causes distinct changes in the morphology,structure,and properties of the graphene nanosheets.Increasing the number of small(6 mm)grinding balls decreases the nanosheet grain size monotonically;meanwhile,the crystal plane spacing,defect density,and specific surface area increase and then decrease,but the graphitization degree decreases and then increases.Ball-milled samples are then used as anodes for lithium-ion batteries,and both the specific capacity and rate capability exhibit the same trend of increase and then decrease.The ball ratio of 1:3 gives the best electrochemical performance,i.e.,a reversible specific capacity of 262.09 mA·h/g at a current density of 100 mA/g,and even after 2000 cycles at 2000 mA/g,the reversible specific capacity is 87.4%of the optimal value.展开更多
The mineralogy and texture of granite have been found to have a pronounced effect on its mechanical behavior.However,the precise manner in which the texture of granite affects the shear behavior of fractures remains e...The mineralogy and texture of granite have been found to have a pronounced effect on its mechanical behavior.However,the precise manner in which the texture of granite affects the shear behavior of fractures remains enigmatic.In this study,fine-grained granite(FG)and coarse-grained granite(CG)were used to create tensile fractures with surface roughness(i.e.joint roughness coefficient(JRC))within the range of 5.48-8.34 and 12.68-16.5,respectively.The pre-fractured specimens were then subjected to direct shear tests under normal stresses of 1-30 MPa.The results reveal that shear strengths are smaller and stick-slip behaviors are more intense for FG fractures than for CG fractures,which is attributed to the different conditions of the shear surface constrained by the grain size.The smaller grain size in FG contributes to the smoother fracture surface and lower shear strength.The negative friction rate parameter a-b for both CG and FG fractures and the larger shear stiffness for FG than for CG fractures can account for the more intense stick-slip behaviors in FG fractures.The relative crack density for the post-shear CG fractures is greater than that of the FG fractures under the same normal stress,both of which decrease with the distance away from the shear surface following the power law.Moreover,the damage of CG fracture extends to a larger extent beneath the surface compared with the FG fracture.Our findings demonstrate that the grain size of the host rock exerts a significant influence on the fracture roughness,and thus should be incorporated into the assessment of fault slip behavior to better understand the role of mineralogy and texture in seismic activities.展开更多
Surface/underwater target classification is a key topic in marine information research.However,the complex underwater environment,coupled with the diversity of target types and their variable characteristics,presents ...Surface/underwater target classification is a key topic in marine information research.However,the complex underwater environment,coupled with the diversity of target types and their variable characteristics,presents significant challenges for classifier design.For shallow-water waveguides with a negative thermocline,a residual neural network(ResNet)model based on the sound field elevation structure is constructed.This model demonstrates robust classification performance even when facing low signal-to-noise ratios and environmental mismatches.Meanwhile,to address the reduced generalization ability caused by limited labeled acoustic data,an improved ResNet model based on unsupervised domain adaptation(“proposed UDA-ResNet”)is further constructed.This model incorporates data on simulated elevation structures of the sound field to augment the training process.Adversarial training is employed to extract domain-invariant features from simulated and trial data.These strategies help reduce the negative impact caused by domain differences.Experimental results demonstrate that the proposed method shows strong surface/underwater target classification ability under limited sample sizes,thus confirming its feasibility and effectiveness.展开更多
Cobalt is undoubtedly the most promising alternative metal to rhodium for a highly active and stable hydroformylation process under mild conditions.In this study,two cobalt-based heterogeneous catalysts were synthesiz...Cobalt is undoubtedly the most promising alternative metal to rhodium for a highly active and stable hydroformylation process under mild conditions.In this study,two cobalt-based heterogeneous catalysts were synthesized via impregnating a cobalt precursor into polymers(POPs-NVP).Comprehensive characterization revealed that the cobalt species on the catalysts exist as CoO with two distinct sizes:nanoparticles and single sites.The CoO nanoparticles on POPs-NVP exhibited outstanding hydroformylation activity(81.7%yield of aldehyde and alcohol,13.5%yield of alkane),while CoO single sites displayed robust olefin hydrogenation performance(62.6%yield of alkane,27.3% yield of aldehyde and alcohol).These divergent catalytic behaviors were attributed to distinct electron density distributions around surface-exposed cobalt species,which were critically governed by CoO sizes on catalysts.By elucidating the size-dependent effects of CoO/POPs-NVP catalysts,this work provided insights into the complex active species states in heterogeneous cobalt-based catalysts,and established valuable experimental and theoretical foundations for designing highly efficient cobalt-based heterogeneous catalysts for hydroformylation.展开更多
Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenizatio...Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenization methods based on the classical elasticity theory struggle to accurately describe the non-classical mechanical behaviors of lattice materials,especially when dealing with complex unit-cell geometries featured by non-symmetric configurations or non-single central node connections.In response to this limitation,this study establishes a generalized homogenization model based on the micropolar theory framework,employing Hill's boundary conditions to precisely predict the equivalent moduli of complex lattice materials.By introducing the independent rotational degree of freedom(DOF)characteristic of the micropolar theory,the proposed model successfully overcomes the limitation of conventional methods in accurately describing the asymmetric deformation and scale effects.We initially calculate the constitutive relations of two-dimensional(2D)cross-shaped multi-node chiral lattices and subsequently extend the method to three-dimensional(3D)lattices,successfully predicting the mechanical properties of both traditional and eccentric body-centered cubic(BCC)lattices.The theoretical model is validated through the finite element numerical verification which shows excellent consistency with the theoretical predictions.A further parametric study investigates the influence of geometric parameters,revealing the underlying size-effect mechanism.This paper provides a reliable theoretical tool for the design and property optimization of complex lattice materials.展开更多
The alpine grassland vegetation on the Qinghai-Tibet Plateau is composed of plant patches in varied sizes.It remains uncertain whether vegetation recovery following grazing exclusion(GE)in degraded grasslands is drive...The alpine grassland vegetation on the Qinghai-Tibet Plateau is composed of plant patches in varied sizes.It remains uncertain whether vegetation recovery following grazing exclusion(GE)in degraded grasslands is driven by increases in patches number(NP),patch size(PS),or both.We based our predictions on two hypotheses:GE intensifies plant competition,and facilitation prevails near patches while competition prevails in interpatch spaces.We predicted that the NP would remain stable or decrease and PS would increase under GE treatment.To evaluate these predictions,we conducted a study in six lightly degraded alpine grasslands under free grazing(FG)conditions in Bangor County,Xizang Autonomous Region,China,with corresponding GE treatments using transects in 2017 and 2018.Results revealed that four sites in 2017 and five sites in 2018 had reduced NP and increased PS,with probabilities of 0.033(2017)and 0.004(2018),respectively,and a joint probability of 0.0001 under the null hypothesis that GE does not affect NP or PS.The NP reduction was solely due to the decrease in small patch sizes.An increase in PS was common across species,and a predominant tendency for NP reduction was observed among species across the sites.The overall changes in NP and PS were primarily driven by the three most abundant species(contributing more than 60%in both years),rather than by shifts in floristic composition.Our findings highlight that vegetation recovery in Bangor alpine steppes following GE relies solely on the expansion of existing patches rather than the recruitment of new ones in interpatch gaps.We recommend prioritizing growth-promoting measures,such as nutrient or water management,over seed addition when assisting with GE for restoring lightly degraded grasslands.展开更多
High-performance magnesium alloys are in great demand to meet the lightweight design requirements of aircraft.Grain size has long been recognized as a key factor influencing the mechanical properties of alloys.This st...High-performance magnesium alloys are in great demand to meet the lightweight design requirements of aircraft.Grain size has long been recognized as a key factor influencing the mechanical properties of alloys.This study investigates the effect of grain size,controlled by Zr addition,on the fatigue behavior of a recently developed low-cost Mg-2.6Nd-0.35Zn alloy,through systematic characterization and analysis of stress-life(S-N)curves,fatigue crack propagation,fracture surface morphology,stress intensity factor,and crack propagation threshold.The results show that after heat treatment(solution at 525±5℃ for 8 h and water quenching at 60-80℃,followed by aging at 250±5℃for 14 h and then air cooling),coarse-grained specimens(average grain size approximately 596μm)containing 0.12wt.%Zr exhibit greater resistance to fatigue crack propagation than fine-grained specimens(average grain size approximately 94μm)containing 0.46wt.%Zr.Coarse grains promote intergranular fracture,while fine grains favor transgranular fracture.In addition,coarse grains reduce the sensitivity of the crack tip to stress concentration.Furthermore,fine-grained samples demonstrate a longer total fatigue life,owing to their superior resistance to crack initiation,which significantly prolongs the crack initiation stage.These findings highlight the importance of optimizing grain size to achieve the best possible fatigue resistance in Mg-Nd-Zn-Zr alloys for practical engineering applications.展开更多
Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study invest...Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study investigates their coupled effects using inclinedflume experiments and Discrete Element Method(DEM)simulations,covering three gravel sizes(2-5 mm,5-7 mm,7-10 mm)and four ice-content levels(0%,20%,40%,60%).Run-out distance,velocity,energy components,flow regime(Savage number),and segregation indexαwere quantified.Increasing ice content significantly enhances mobility,but with diminishing marginal effectiveness.From 0%to 40%ice content,run-out distance increases by 41%-86%,whereas the additional increase from 40%to 60%contributes only 12%-23%.Particle-size ratio strongly governs segregation intensity.Fine-gravel groups reach segregation indices ofα=0.92-0.98,indicating nearly complete upward migration of ice,whereas medium-gravel and coarse-gravel groups exhibit much weaker segregation,stabilizing atα=0.68-0.74 and 0.60-0.69.Savage number analyses reveal marked flow-regime transitions.At 0%ice content,Savage numbers reach 1.0-1.5,indicating a collisional regime.Increasing ice content suppresses collisionality,with Savage numbers decreasing to 0.03-0.07 at 60%ice content,consistent with dense-regime flow.DEM energy analyses confirm this regime shift:for finegravel mixtures,collision energy decreases by 14%,while sliding-friction energy increases by 33%as ice content increases from 0%to 60%,reflecting enhanced overburden effects imposed by upward-segregated ice layers.Medium and coarse mixtures exhibit weaker or opposite energy-shift patterns,demonstrating strong size dependence.Mechanistically,large particle-size contrasts promote strong segregation and form dense basal rock layers that increase basal friction and reduce mobility.When particle sizes are similar or ice content is high,segregation remains limited,allowing ice to mix into the basal layer,thereby reducing basal friction and enhancing mobility.This research quantitatively demonstrates how composition controls particle spatial distribution,flow regime,and energy dissipation,offering new mechanistic insights into the propagation and deposition behaviors of rock-ice avalanches and improving hazard assessment in vulnerable high-mountain regions.展开更多
Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis t...Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis to examine the grain size characteristics of major riparian dunes in the typical cold and arid deserts of China.The results indicate that major riparian dunes of deserts in study area can be classified into three types based on their grain size characteristics.The Bartlett test of sphericity and the Kaiser-Meyer-Olkin(KMO)test were also performed,and their significance values were found to be 0.000 and 0.584,respectively.The results of the principal component analysis revealed that the cumulative contribution rate of the total variance reached 85.9%for the two principal components with characteristic roots greater than 1.0.The primary principal component included medium sand,whereas the secondary principal component included fine sand.We conducted a cluster analysis and classified the samples into three major types.Type I rivers include the Keriya River,Langqu River,Tora River and Heihe River,which are characterized by by fine particle size,and well-sorted.Type II includes Mu Bulag River,Kuye River,and the Xar Moron River,Compared with type I,it has a relatively coarser mean grain size and relatively poor sorting for this type.Type III includes the Maquan River,which is characterized mainly by fine sand and medium sand,accounting for more than 90%,and the sorting coefficient(0.52)suggests relatively well sorting in this pattern.Moreover,principal component analysis was applied to determine the particle sizes of samples from different watersheds.Moreover,these sediments exhibit both hydromorphic and aeolian features.At the drainage basin scale,the mode and intensity of aeolian-fluvial interactions depend on climatic conditions.In arid and semi-arid climate regions,wind is the dominant force,and the grain size exhibits significant aeolian features.Conversely,in the semi-humid region,flowing water is the dominant force,and riparian dunes in this region are formed by aeolian-fluvial interaction.The angle between the wind direction and flow direction in different reaches influences both the supply of sediment sources and the development of riparian dunes.This study will provide a new perspective for evaluating aeolian-fluvial interactions on riparian dunes in the deserts of China’s cold and arid regions.展开更多
Landslide dams often undergo seepage due to poor particle gradation and loose structure,yet most existing studies focus solely on overtopping-induced breaching mechanisms,neglecting the potential influence of pre-brea...Landslide dams often undergo seepage due to poor particle gradation and loose structure,yet most existing studies focus solely on overtopping-induced breaching mechanisms,neglecting the potential influence of pre-breaching seepage.Seepage may alter the dam's erodibility,structural stability,and material composition,thereby affecting the overtopping breaching process.Through flume experiments,this study investigates the breaching mechanisms of cohesionless landslide dams with different gradations within the same particle size range under coupled seepage-overtopping conditions.The results demonstrate that pre-breaching seepage significantly impacts breaching dynamics.Within a specific particle size range,compared to pure overtopping,seepage reduces downstream slope stability,increases material erodibility,shortens breaching duration,amplifies peak discharge,and advances the timing of peak flow.As the median particle size(D_(50))increases,the amplification effect of seepage on peak discharge initially increases then decreases,the advancement of peak flow timing diminishes,and the breach erosion rate declines.When D_(50)is sufficiently large,seepage has negligible effects on breach development.For smaller D_(50),seepage markedly accelerates breach widening and deepening.Furthermore,coupled seepage-overtopping extends the downstream deposition area and exacerbates channel erosion due to differences in sediment sorting.These findings highlight the critical role of seepage in landslide dam breaching,providing a scientific basis for hazard prevention and mitigation.展开更多
With the development of the semiconductor industry below the 7 nm scale,critical dimension small-angle X-ray scattering(CD-SAXS)has emerged as a powerful tool for quantitatively measuring nanoscale deviations.In this ...With the development of the semiconductor industry below the 7 nm scale,critical dimension small-angle X-ray scattering(CD-SAXS)has emerged as a powerful tool for quantitatively measuring nanoscale deviations.In this study,the effects of X-ray beam size and photon energy on the accuracy of critical dimension measurements were investigated.Critical dimensions measured using beams with different spot sizes showed different deviations from the expected values.Beam sizes that were either too large or too small did not improve confidence intervals.As the incident energy increased,the X-ray transmission rate increased,while the scattering cross section decreased,resulting in a gradual decrease in the signal-to-noise ratio of the diffraction peaks,which reduced the accuracy of the CD-SAXS measurements.An optimal accuracy was obtained at 12 keV with a smaller beam size.Using an effective trapezoid model,the results yielded an average pitch of 100.4±0.2 nm,width of 49.8±0.2 nm,height of 130.0±0.2 nm,and a sidewall angle below 1.1°±0.1°.These results provide crucial guidance for the future development of CD-SAXS laboratories and the construction of X-ray machines as well as robust support for research in related fields.展开更多
The specific surface area(S S)and pore size(D)exhibit an inherent trade-off in the microscale design of bone implants:larger pores typically correlate with reduced surface area and vice versa.This relationship has att...The specific surface area(S S)and pore size(D)exhibit an inherent trade-off in the microscale design of bone implants:larger pores typically correlate with reduced surface area and vice versa.This relationship has attracted notable attention because of its critical role in the regulation of cell adhesion and osteogenesis.However,it remains largely unclear how S S and D affect the generated bone tissue and dynamically change during long-term osteogenesis.Herein,by applying rigorous geometric mapping to minimal surfaces,we constructed precisely partitioned and layer-by-layer thickened tissue models to simulate osteogenesis across different temporal scales and thereby track the dynamic evolution of geometric characteristics,permeability,and mechanobiological tissue differentiation.The high-S S samples were found to facilitate the rapid formation of new bone tissue in the early stages.However,their smaller pores tended to cause occlusions,hindering further tissue development.In contrast,low-S S samples showed slower bone regeneration,but their larger pores provided adequate physical space for tissue regeneration and mass transport,ultimately promoting bone formation in the long term.Mechanobiological regulation suggests that fibrous tissue formation inhibits additional bone formation,establishing a dynamic equilibrium between osteogenesis and pore space to sustain nutrient/waste exchange throughout the regenerative process.Overall,smaller pores are preferable in implants for minimally loaded osteoplasty procedures focused on early-stage bone consolidation,whereas larger pores are preferable in dynamically loaded implants requiring prolonged mechanical stability.展开更多
Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces th...Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces the accuracy of conventional methods.This article proposes a user-friendly software for PSD analysis,GranuSAS,which employs an algorithm that integrates truncated singular value decomposition(TSVD)with the Chahine method.This approach employs TSVD for data preprocessing,generating a set of initial solutions with noise suppression.A high-quality initial solution is subsequently selected via the L-curve method.This selected candidate solution is then iteratively refined by the Chahine algorithm,enforcing constraints such as non-negativity and improving physical interpretability.Most importantly,GranuSAS employs a parallel architecture that simultaneously yields inversion results from multiple shape models and,by evaluating the accuracy of each model's reconstructed scattering curve,offers a suggestion for model selection in material systems.To systematically validate the accuracy and efficiency of the software,verification was performed using both simulated and experimental datasets.The results demonstrate that the proposed software delivers both satisfactory accuracy and reliable computational efficiency.It provides an easy-to-use and reliable tool for researchers in materials science,helping them fully exploit the potential of SAXS in nanoparticle characterization.展开更多
Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment...Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment,the firstproblem to be solved is how to introduce and retain the bacterial cells in the soil,which involves the migration and retention of bacterial cells during the biogrouting process.Soil particle size,a key factor in determining pore throat size,can have a significanteffect on the migration and retention of bacterial cells in the soil and therefore on biomineralization.To investigate the effect of particle size on the migration and retention of bacterial cells in sand and its biomineralization,two sets of tests were carried out in this study,including percolation tests and sand column treatment tests.Soil urease activity(definedas urease activity per unit mass of soil)and calcium carbonate content of the biomineralized sand were measured to comprehensively assess the migration and retention of bacterial cells in the sand.The results indicate that sands with a particle size smaller than 0.25 mmwould inhibit the migration of bacteria in the sand,resulting in a nonuniform distribution of precipitated calcium carbonate and a low strength enhancement of biomineralization.On the other hand,sands with a particle size larger than 1.18 mm are unfavorable for retaining bacterial cells in the sand,resulting in low calcium conversion efficiency.Meanwhile,particle size would also affect the formation of effective calcium carbonate through interparticle contact number and interparticle pore size,and thus biomineralization.展开更多
Cemented rockfill(CRF)combines structural support with sustainable reuse of coal-derived solid waste.This study integrates digital image correlation,acoustic emission monitoring,and finite-discrete element simulations...Cemented rockfill(CRF)combines structural support with sustainable reuse of coal-derived solid waste.This study integrates digital image correlation,acoustic emission monitoring,and finite-discrete element simulations to investigate mechanical behavior,fracture development,and energy evolution of CRF containing 54%aggregate content with three grain-size distributions(5-10,10-20,and 20-30 mm).Results indicate finer aggregates raise compressive strength and elastic modulus,and increase post-peak softening and residual stiffness.Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens,with cracks initiating at boundaries and propagating inward.The proportion of failed joints at comparable strains decreases markedly with finer gradation,reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations.Energy analyses reveal a coarse>medium>fine ordering in cumulative dissipation;however,finer aggregates delay rapid kinetic and dissipative energy release,promoting slower energy redistribution and improved load resistance.These findings quantify how aggregate gradation controls deformational mechanisms,crack topology,and energy partitioning,and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility,energy absorption,and structural reliability of CRF in underground engineering.展开更多
On January 19,2026,China's first structural interest rate cut of the year took effect.The People's Bank of China announced a 0.25 percentage point reduction in relending and rediscount rates,targeting key sect...On January 19,2026,China's first structural interest rate cut of the year took effect.The People's Bank of China announced a 0.25 percentage point reduction in relending and rediscount rates,targeting key sectors like small and micro enterprises(SMEs),technological innovation,and green transition.For the textile industry,where small and medium-sized enterprises account for over 90%of traditional manufacturing,the policy benefits will inject strong momentum into the high-quality development from multiple dimensions,including reduced financing costs,support for transformation funds,and expansion of foreign trade markets.展开更多
To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallur...To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallurgy. The microstructure of Ag?4%SnO2 contact materials was characterized, and the relative density, hardness and electrical conductivity were measured. The arc erosion of Ag?4%SnO2 contact materials was tested, the arc duration and mass loss before and after arc erosion were determined, the surface morphologies and compositions of Ag?4%SnO2 contact materials after arc erosion were characterized, and the arc erosion mechanism of AgSnO2 contact materials was discussed. The results show that fine SnO2 particle is beneficial for the improvement of the relative density and hardness, but decreases the electrical conductivity. With the decrease of SnO2 particle size, Ag?4%SnO2contact material presents shorter arc duration, less mass loss, larger erosion area and shallower arc erosion pits.展开更多
The significance of soil mineral properties and secondary environmental conditions such as pH, temperature, ionic strength and time in the partitioning of eight selected polychlorinated biphenyl(PCB) congeners between...The significance of soil mineral properties and secondary environmental conditions such as pH, temperature, ionic strength and time in the partitioning of eight selected polychlorinated biphenyl(PCB) congeners between aqueous solution and soil particles with different grain sizes was studied. The mineral properties of a model soil sample were determined, and Brunauer–Emmett–Teller(BET) adsorption–desorption isotherms were employed to observe the surface characteristics of the individual modeled soil particles.Batch adsorption experiments were conducted to determine the sorption of PCBs onto soil particles of different sizes. The results revealed that the sorption of PCB congeners onto the soil was dependent on the amount of soil organic matter, surface area, and pore size distribution of the various individual soil particles. Low pH favored the sorption of PCBs,with maximum sorption occurring between pH 6.5 and 7.5 with an equilibration period of 8 hr.Changes in the ionic strength were found to be less significant. Low temperature favored the sorption of PCBs onto the soil compared to high temperatures. Thermodynamic studies showed that the partition coefficient(K_d) decreased with increasing temperature, and negative and low values of ΔH° indicated an exothermic physisorption process. The data generated is critical and will help in further understanding remediation and cleanup strategies for polluted water.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.12202294 and 12022208)the Project funded by China Postdoctoral Science Foundation (Grant No.2022M712243)the Fundamental Research Funds for the Central Universities (Grant No.2023SCU12098).
文摘It is well known that coarse-grained super-elastic NiTi shape memory alloys(SMAs)exhibit localized rather than homogeneous martensite transformation(MT),which,however,can be strongly influenced by either internal size(grain size,GS)or the external size(geometric size).The coupled effect of GS and geometric size on the functional properties has not been clearly understood yet.In this work,the super-elasticity,one-way,and stress-assisted two-way shape memory effects of the polycrystalline NiTi SMAs with different aspect ratios(length/width for the gauge section)and different GSs are investigated based on the phase field method.The coupled effect of the aspect ratio and GS on the functional properties is adequately revealed.The simulated results indicate that when the aspect ratio is lower than about 4:1,the stress biaxiality and stress heterogeneity in the gauge section of the sample become more and more obvious with decreasing the aspect ratio,which can significantly influence the microstructure evolution in the process involving external stress.Therefore,the corresponding functional property is strongly dependent on the aspect ratio.With decreasing the GS and the aspect ratio(to be lower than 4:1),both the aspect ratio and GS can affect the MT or martensite reorientation in each grain and the interaction among grains.Thus,due to the strong internal constraint(i.e.,the constraint of grain boundary)and the external constraint(i.e.,the constraint of geometric boundary),the capabilities of the functional properties of NiTi SMAs are gradually weakened and highly dependent on these two factors.
基金supported by a grant from the National Natural Science Foundation of China(82173353)。
文摘Background:The rate of distant metastasis in patients with pancreatic neuroendocrine tumors(PNETs)is20%-50%at the time of initial diagnosis.However,whether tumor size can predict distant metastasis for PNETs remains unknown up to date.Methods:We used Surveillance,Epidemiology,and End Results(SEER)population-based data to collect6089 patients with PNETs from 2010 to 2019.The optimal cut-off point of tumor size to predict distant metastasis was calculated by Youden’s index.Multivariate logistic regression analysis was used to figure out the association between tumor size and distant metastasis patterns.Results:The most common metastatic site was liver(27.2%),followed by bone(3.0%),lung(2.3%)and brain(0.4%).Based on an optimal cut-off value of tumor size(25.5 mm)for predicting distant metastasis determined by Youden’s index,patients were categorized into groups of tumor size<25.5 mm and≥25.5 mm.Multivariate logistic regression analyses showed that,compared with<25.5 mm,tumor size≥25.5 mm was an independent risk predictor of overall distant metastasis[odds ratio(OR)=4.491,95%confidence interval(CI):3.724-5.416,P<0.001]and liver metastasis(OR=4.686,95%CI:3.886-5.651,P<0.001).Conclusions:Tumor size≥25.5 mm was significantly associated with more overall distant and liver metastases.Timely identification of distant metastasis for tumor size≥25.5 mm may provide survival benefit for timely and precise treatment.
基金supported financially by the National Natural Science Foundation of China(Grant No.12275047).
文摘In ball milling,the process parameters are decisive in influencing the quality and performance of the final ball-milled product,and crucial but often neglected is the ratio of the grinding balls in terms of their size.Here,for a given number of large grinding balls,the ratio of large to small ones is set to 1:2,1:3,1:4,and 1:5 by altering the number of small ones,and how this affects the morphology,structure,and electrochemical properties of ball-milled graphene nanosheets is investigated.The results show that changing the ball ratio causes distinct changes in the morphology,structure,and properties of the graphene nanosheets.Increasing the number of small(6 mm)grinding balls decreases the nanosheet grain size monotonically;meanwhile,the crystal plane spacing,defect density,and specific surface area increase and then decrease,but the graphitization degree decreases and then increases.Ball-milled samples are then used as anodes for lithium-ion batteries,and both the specific capacity and rate capability exhibit the same trend of increase and then decrease.The ball ratio of 1:3 gives the best electrochemical performance,i.e.,a reversible specific capacity of 262.09 mA·h/g at a current density of 100 mA/g,and even after 2000 cycles at 2000 mA/g,the reversible specific capacity is 87.4%of the optimal value.
基金the National Natural Science Foundation of China(Grant No.52309130)the Natural Science Foundation of Shandong Province(Grant No.ZR2022QD004).
文摘The mineralogy and texture of granite have been found to have a pronounced effect on its mechanical behavior.However,the precise manner in which the texture of granite affects the shear behavior of fractures remains enigmatic.In this study,fine-grained granite(FG)and coarse-grained granite(CG)were used to create tensile fractures with surface roughness(i.e.joint roughness coefficient(JRC))within the range of 5.48-8.34 and 12.68-16.5,respectively.The pre-fractured specimens were then subjected to direct shear tests under normal stresses of 1-30 MPa.The results reveal that shear strengths are smaller and stick-slip behaviors are more intense for FG fractures than for CG fractures,which is attributed to the different conditions of the shear surface constrained by the grain size.The smaller grain size in FG contributes to the smoother fracture surface and lower shear strength.The negative friction rate parameter a-b for both CG and FG fractures and the larger shear stiffness for FG than for CG fractures can account for the more intense stick-slip behaviors in FG fractures.The relative crack density for the post-shear CG fractures is greater than that of the FG fractures under the same normal stress,both of which decrease with the distance away from the shear surface following the power law.Moreover,the damage of CG fracture extends to a larger extent beneath the surface compared with the FG fracture.Our findings demonstrate that the grain size of the host rock exerts a significant influence on the fracture roughness,and thus should be incorporated into the assessment of fault slip behavior to better understand the role of mineralogy and texture in seismic activities.
基金supported by the National Natural Science Foundation of China(Grant Nos.62471024 and 62301183)the Open Research Fund of Hanjiang Laboratory(KF2024001).
文摘Surface/underwater target classification is a key topic in marine information research.However,the complex underwater environment,coupled with the diversity of target types and their variable characteristics,presents significant challenges for classifier design.For shallow-water waveguides with a negative thermocline,a residual neural network(ResNet)model based on the sound field elevation structure is constructed.This model demonstrates robust classification performance even when facing low signal-to-noise ratios and environmental mismatches.Meanwhile,to address the reduced generalization ability caused by limited labeled acoustic data,an improved ResNet model based on unsupervised domain adaptation(“proposed UDA-ResNet”)is further constructed.This model incorporates data on simulated elevation structures of the sound field to augment the training process.Adversarial training is employed to extract domain-invariant features from simulated and trial data.These strategies help reduce the negative impact caused by domain differences.Experimental results demonstrate that the proposed method shows strong surface/underwater target classification ability under limited sample sizes,thus confirming its feasibility and effectiveness.
基金supported by the National Key Research and Development Program of China(2023YFA1508003)the National Natural Science Foundation of China(22408363,22302192)+6 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA29050300)the Youth Innovation Promotion Association CAS(2021181)the Key Research and Development Program of Liaoning(2023JH2/101800051)the Dalian of Science and Technology Project(2023RY012)the Postdoctoral Fellowship Program of CPSF(GZC20241677,GZB20230724)the Postdoctoral Science Foundation(2024T170900)the Doctoral Research Start-up Fund of Liaoning(2024-BSBA-28)。
文摘Cobalt is undoubtedly the most promising alternative metal to rhodium for a highly active and stable hydroformylation process under mild conditions.In this study,two cobalt-based heterogeneous catalysts were synthesized via impregnating a cobalt precursor into polymers(POPs-NVP).Comprehensive characterization revealed that the cobalt species on the catalysts exist as CoO with two distinct sizes:nanoparticles and single sites.The CoO nanoparticles on POPs-NVP exhibited outstanding hydroformylation activity(81.7%yield of aldehyde and alcohol,13.5%yield of alkane),while CoO single sites displayed robust olefin hydrogenation performance(62.6%yield of alkane,27.3% yield of aldehyde and alcohol).These divergent catalytic behaviors were attributed to distinct electron density distributions around surface-exposed cobalt species,which were critically governed by CoO sizes on catalysts.By elucidating the size-dependent effects of CoO/POPs-NVP catalysts,this work provided insights into the complex active species states in heterogeneous cobalt-based catalysts,and established valuable experimental and theoretical foundations for designing highly efficient cobalt-based heterogeneous catalysts for hydroformylation.
基金Project supported by the National Natural Science Foundation of China(No.12472077)the supports from Shanghai Gaofeng Project for University Academic Program Development,Fundamental Research Funds for the Central Universities(No.22120240353).
文摘Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenization methods based on the classical elasticity theory struggle to accurately describe the non-classical mechanical behaviors of lattice materials,especially when dealing with complex unit-cell geometries featured by non-symmetric configurations or non-single central node connections.In response to this limitation,this study establishes a generalized homogenization model based on the micropolar theory framework,employing Hill's boundary conditions to precisely predict the equivalent moduli of complex lattice materials.By introducing the independent rotational degree of freedom(DOF)characteristic of the micropolar theory,the proposed model successfully overcomes the limitation of conventional methods in accurately describing the asymmetric deformation and scale effects.We initially calculate the constitutive relations of two-dimensional(2D)cross-shaped multi-node chiral lattices and subsequently extend the method to three-dimensional(3D)lattices,successfully predicting the mechanical properties of both traditional and eccentric body-centered cubic(BCC)lattices.The theoretical model is validated through the finite element numerical verification which shows excellent consistency with the theoretical predictions.A further parametric study investigates the influence of geometric parameters,revealing the underlying size-effect mechanism.This paper provides a reliable theoretical tool for the design and property optimization of complex lattice materials.
基金financially supported by the Science and Technology Bureau of Ali Prefecture,project named“Assessing the Carbon Sequestration and Carbon Sink Enhancement Potential of Natural Ecosystems in Ali Region(QYXTZX-AL2022-05)”。
文摘The alpine grassland vegetation on the Qinghai-Tibet Plateau is composed of plant patches in varied sizes.It remains uncertain whether vegetation recovery following grazing exclusion(GE)in degraded grasslands is driven by increases in patches number(NP),patch size(PS),or both.We based our predictions on two hypotheses:GE intensifies plant competition,and facilitation prevails near patches while competition prevails in interpatch spaces.We predicted that the NP would remain stable or decrease and PS would increase under GE treatment.To evaluate these predictions,we conducted a study in six lightly degraded alpine grasslands under free grazing(FG)conditions in Bangor County,Xizang Autonomous Region,China,with corresponding GE treatments using transects in 2017 and 2018.Results revealed that four sites in 2017 and five sites in 2018 had reduced NP and increased PS,with probabilities of 0.033(2017)and 0.004(2018),respectively,and a joint probability of 0.0001 under the null hypothesis that GE does not affect NP or PS.The NP reduction was solely due to the decrease in small patch sizes.An increase in PS was common across species,and a predominant tendency for NP reduction was observed among species across the sites.The overall changes in NP and PS were primarily driven by the three most abundant species(contributing more than 60%in both years),rather than by shifts in floristic composition.Our findings highlight that vegetation recovery in Bangor alpine steppes following GE relies solely on the expansion of existing patches rather than the recruitment of new ones in interpatch gaps.We recommend prioritizing growth-promoting measures,such as nutrient or water management,over seed addition when assisting with GE for restoring lightly degraded grasslands.
文摘High-performance magnesium alloys are in great demand to meet the lightweight design requirements of aircraft.Grain size has long been recognized as a key factor influencing the mechanical properties of alloys.This study investigates the effect of grain size,controlled by Zr addition,on the fatigue behavior of a recently developed low-cost Mg-2.6Nd-0.35Zn alloy,through systematic characterization and analysis of stress-life(S-N)curves,fatigue crack propagation,fracture surface morphology,stress intensity factor,and crack propagation threshold.The results show that after heat treatment(solution at 525±5℃ for 8 h and water quenching at 60-80℃,followed by aging at 250±5℃for 14 h and then air cooling),coarse-grained specimens(average grain size approximately 596μm)containing 0.12wt.%Zr exhibit greater resistance to fatigue crack propagation than fine-grained specimens(average grain size approximately 94μm)containing 0.46wt.%Zr.Coarse grains promote intergranular fracture,while fine grains favor transgranular fracture.In addition,coarse grains reduce the sensitivity of the crack tip to stress concentration.Furthermore,fine-grained samples demonstrate a longer total fatigue life,owing to their superior resistance to crack initiation,which significantly prolongs the crack initiation stage.These findings highlight the importance of optimizing grain size to achieve the best possible fatigue resistance in Mg-Nd-Zn-Zr alloys for practical engineering applications.
基金funded by the Natural Science Foundation of China(Grants No 42277127)。
文摘Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study investigates their coupled effects using inclinedflume experiments and Discrete Element Method(DEM)simulations,covering three gravel sizes(2-5 mm,5-7 mm,7-10 mm)and four ice-content levels(0%,20%,40%,60%).Run-out distance,velocity,energy components,flow regime(Savage number),and segregation indexαwere quantified.Increasing ice content significantly enhances mobility,but with diminishing marginal effectiveness.From 0%to 40%ice content,run-out distance increases by 41%-86%,whereas the additional increase from 40%to 60%contributes only 12%-23%.Particle-size ratio strongly governs segregation intensity.Fine-gravel groups reach segregation indices ofα=0.92-0.98,indicating nearly complete upward migration of ice,whereas medium-gravel and coarse-gravel groups exhibit much weaker segregation,stabilizing atα=0.68-0.74 and 0.60-0.69.Savage number analyses reveal marked flow-regime transitions.At 0%ice content,Savage numbers reach 1.0-1.5,indicating a collisional regime.Increasing ice content suppresses collisionality,with Savage numbers decreasing to 0.03-0.07 at 60%ice content,consistent with dense-regime flow.DEM energy analyses confirm this regime shift:for finegravel mixtures,collision energy decreases by 14%,while sliding-friction energy increases by 33%as ice content increases from 0%to 60%,reflecting enhanced overburden effects imposed by upward-segregated ice layers.Medium and coarse mixtures exhibit weaker or opposite energy-shift patterns,demonstrating strong size dependence.Mechanistically,large particle-size contrasts promote strong segregation and form dense basal rock layers that increase basal friction and reduce mobility.When particle sizes are similar or ice content is high,segregation remains limited,allowing ice to mix into the basal layer,thereby reducing basal friction and enhancing mobility.This research quantitatively demonstrates how composition controls particle spatial distribution,flow regime,and energy dissipation,offering new mechanistic insights into the propagation and deposition behaviors of rock-ice avalanches and improving hazard assessment in vulnerable high-mountain regions.
基金Under the auspices of the General Project of Science and Technology Department of Shaanxi Province(No.2023-JCYB-264)General Program of National Natural Science Foundation of China(No.41801004,42371008,42471012)。
文摘Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis to examine the grain size characteristics of major riparian dunes in the typical cold and arid deserts of China.The results indicate that major riparian dunes of deserts in study area can be classified into three types based on their grain size characteristics.The Bartlett test of sphericity and the Kaiser-Meyer-Olkin(KMO)test were also performed,and their significance values were found to be 0.000 and 0.584,respectively.The results of the principal component analysis revealed that the cumulative contribution rate of the total variance reached 85.9%for the two principal components with characteristic roots greater than 1.0.The primary principal component included medium sand,whereas the secondary principal component included fine sand.We conducted a cluster analysis and classified the samples into three major types.Type I rivers include the Keriya River,Langqu River,Tora River and Heihe River,which are characterized by by fine particle size,and well-sorted.Type II includes Mu Bulag River,Kuye River,and the Xar Moron River,Compared with type I,it has a relatively coarser mean grain size and relatively poor sorting for this type.Type III includes the Maquan River,which is characterized mainly by fine sand and medium sand,accounting for more than 90%,and the sorting coefficient(0.52)suggests relatively well sorting in this pattern.Moreover,principal component analysis was applied to determine the particle sizes of samples from different watersheds.Moreover,these sediments exhibit both hydromorphic and aeolian features.At the drainage basin scale,the mode and intensity of aeolian-fluvial interactions depend on climatic conditions.In arid and semi-arid climate regions,wind is the dominant force,and the grain size exhibits significant aeolian features.Conversely,in the semi-humid region,flowing water is the dominant force,and riparian dunes in this region are formed by aeolian-fluvial interaction.The angle between the wind direction and flow direction in different reaches influences both the supply of sediment sources and the development of riparian dunes.This study will provide a new perspective for evaluating aeolian-fluvial interactions on riparian dunes in the deserts of China’s cold and arid regions.
基金support of the National Natural Science Foundation of China(42107189,U20A20111)。
文摘Landslide dams often undergo seepage due to poor particle gradation and loose structure,yet most existing studies focus solely on overtopping-induced breaching mechanisms,neglecting the potential influence of pre-breaching seepage.Seepage may alter the dam's erodibility,structural stability,and material composition,thereby affecting the overtopping breaching process.Through flume experiments,this study investigates the breaching mechanisms of cohesionless landslide dams with different gradations within the same particle size range under coupled seepage-overtopping conditions.The results demonstrate that pre-breaching seepage significantly impacts breaching dynamics.Within a specific particle size range,compared to pure overtopping,seepage reduces downstream slope stability,increases material erodibility,shortens breaching duration,amplifies peak discharge,and advances the timing of peak flow.As the median particle size(D_(50))increases,the amplification effect of seepage on peak discharge initially increases then decreases,the advancement of peak flow timing diminishes,and the breach erosion rate declines.When D_(50)is sufficiently large,seepage has negligible effects on breach development.For smaller D_(50),seepage markedly accelerates breach widening and deepening.Furthermore,coupled seepage-overtopping extends the downstream deposition area and exacerbates channel erosion due to differences in sediment sorting.These findings highlight the critical role of seepage in landslide dam breaching,providing a scientific basis for hazard prevention and mitigation.
基金supported by the National Natural Science Foundation of China(No.12175295)the National Key R&D Program of China(2021YFA1601000)the Shanghai Municipal Science and Technology Major Project。
文摘With the development of the semiconductor industry below the 7 nm scale,critical dimension small-angle X-ray scattering(CD-SAXS)has emerged as a powerful tool for quantitatively measuring nanoscale deviations.In this study,the effects of X-ray beam size and photon energy on the accuracy of critical dimension measurements were investigated.Critical dimensions measured using beams with different spot sizes showed different deviations from the expected values.Beam sizes that were either too large or too small did not improve confidence intervals.As the incident energy increased,the X-ray transmission rate increased,while the scattering cross section decreased,resulting in a gradual decrease in the signal-to-noise ratio of the diffraction peaks,which reduced the accuracy of the CD-SAXS measurements.An optimal accuracy was obtained at 12 keV with a smaller beam size.Using an effective trapezoid model,the results yielded an average pitch of 100.4±0.2 nm,width of 49.8±0.2 nm,height of 130.0±0.2 nm,and a sidewall angle below 1.1°±0.1°.These results provide crucial guidance for the future development of CD-SAXS laboratories and the construction of X-ray machines as well as robust support for research in related fields.
基金financial support from the National Natural Science Foundation of China(No.52035012)the Guangdong Basic and Applied Basic Research Foundation(No.2025A1515012203)。
文摘The specific surface area(S S)and pore size(D)exhibit an inherent trade-off in the microscale design of bone implants:larger pores typically correlate with reduced surface area and vice versa.This relationship has attracted notable attention because of its critical role in the regulation of cell adhesion and osteogenesis.However,it remains largely unclear how S S and D affect the generated bone tissue and dynamically change during long-term osteogenesis.Herein,by applying rigorous geometric mapping to minimal surfaces,we constructed precisely partitioned and layer-by-layer thickened tissue models to simulate osteogenesis across different temporal scales and thereby track the dynamic evolution of geometric characteristics,permeability,and mechanobiological tissue differentiation.The high-S S samples were found to facilitate the rapid formation of new bone tissue in the early stages.However,their smaller pores tended to cause occlusions,hindering further tissue development.In contrast,low-S S samples showed slower bone regeneration,but their larger pores provided adequate physical space for tissue regeneration and mass transport,ultimately promoting bone formation in the long term.Mechanobiological regulation suggests that fibrous tissue formation inhibits additional bone formation,establishing a dynamic equilibrium between osteogenesis and pore space to sustain nutrient/waste exchange throughout the regenerative process.Overall,smaller pores are preferable in implants for minimally loaded osteoplasty procedures focused on early-stage bone consolidation,whereas larger pores are preferable in dynamically loaded implants requiring prolonged mechanical stability.
基金Project supported by the Project of the Anhui Provincial Natural Science Foundation(Grant No.2308085MA19)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA0410401)+2 种基金the National Natural Science Foundation of China(Grant No.52202120)the National Key Research and Development Program of China(Grant No.2023YFA1609800)USTC Research Funds of the Double First-Class Initiative(Grant No.YD2310002013)。
文摘Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces the accuracy of conventional methods.This article proposes a user-friendly software for PSD analysis,GranuSAS,which employs an algorithm that integrates truncated singular value decomposition(TSVD)with the Chahine method.This approach employs TSVD for data preprocessing,generating a set of initial solutions with noise suppression.A high-quality initial solution is subsequently selected via the L-curve method.This selected candidate solution is then iteratively refined by the Chahine algorithm,enforcing constraints such as non-negativity and improving physical interpretability.Most importantly,GranuSAS employs a parallel architecture that simultaneously yields inversion results from multiple shape models and,by evaluating the accuracy of each model's reconstructed scattering curve,offers a suggestion for model selection in material systems.To systematically validate the accuracy and efficiency of the software,verification was performed using both simulated and experimental datasets.The results demonstrate that the proposed software delivers both satisfactory accuracy and reliable computational efficiency.It provides an easy-to-use and reliable tool for researchers in materials science,helping them fully exploit the potential of SAXS in nanoparticle characterization.
基金support by the National Natural Science Foundation of China(NSFC)(Grant Nos.52178319,42477160,52338007).
文摘Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment,the firstproblem to be solved is how to introduce and retain the bacterial cells in the soil,which involves the migration and retention of bacterial cells during the biogrouting process.Soil particle size,a key factor in determining pore throat size,can have a significanteffect on the migration and retention of bacterial cells in the soil and therefore on biomineralization.To investigate the effect of particle size on the migration and retention of bacterial cells in sand and its biomineralization,two sets of tests were carried out in this study,including percolation tests and sand column treatment tests.Soil urease activity(definedas urease activity per unit mass of soil)and calcium carbonate content of the biomineralized sand were measured to comprehensively assess the migration and retention of bacterial cells in the sand.The results indicate that sands with a particle size smaller than 0.25 mmwould inhibit the migration of bacteria in the sand,resulting in a nonuniform distribution of precipitated calcium carbonate and a low strength enhancement of biomineralization.On the other hand,sands with a particle size larger than 1.18 mm are unfavorable for retaining bacterial cells in the sand,resulting in low calcium conversion efficiency.Meanwhile,particle size would also affect the formation of effective calcium carbonate through interparticle contact number and interparticle pore size,and thus biomineralization.
基金funding from the National Natural Science Foundation of China(Nos.52478389 and 52525401).
文摘Cemented rockfill(CRF)combines structural support with sustainable reuse of coal-derived solid waste.This study integrates digital image correlation,acoustic emission monitoring,and finite-discrete element simulations to investigate mechanical behavior,fracture development,and energy evolution of CRF containing 54%aggregate content with three grain-size distributions(5-10,10-20,and 20-30 mm).Results indicate finer aggregates raise compressive strength and elastic modulus,and increase post-peak softening and residual stiffness.Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens,with cracks initiating at boundaries and propagating inward.The proportion of failed joints at comparable strains decreases markedly with finer gradation,reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations.Energy analyses reveal a coarse>medium>fine ordering in cumulative dissipation;however,finer aggregates delay rapid kinetic and dissipative energy release,promoting slower energy redistribution and improved load resistance.These findings quantify how aggregate gradation controls deformational mechanisms,crack topology,and energy partitioning,and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility,energy absorption,and structural reliability of CRF in underground engineering.
文摘On January 19,2026,China's first structural interest rate cut of the year took effect.The People's Bank of China announced a 0.25 percentage point reduction in relending and rediscount rates,targeting key sectors like small and micro enterprises(SMEs),technological innovation,and green transition.For the textile industry,where small and medium-sized enterprises account for over 90%of traditional manufacturing,the policy benefits will inject strong momentum into the high-quality development from multiple dimensions,including reduced financing costs,support for transformation funds,and expansion of foreign trade markets.
基金Project(51274163)supported by the National Natural Science Foundation of ChinaProject(13JS076)supported by the Key Laboratory Research Program of Shaanxi Province,China+1 种基金Project(2012KCT-25)supported by the Pivot Innovation Team of Shaanxi Electrical Materials and Infiltration Technique,ChinaProject(2011HBSZS009)supported by the Special Foundation of Key Disciplines,China
文摘To clarify the effect of SnO2 particle size on the arc erosion behavior of AgSnO2 contact material, Ag?4%SnO2 (mass fraction) contact materials with different sizes of SnO2 particles were fabricated by powder metallurgy. The microstructure of Ag?4%SnO2 contact materials was characterized, and the relative density, hardness and electrical conductivity were measured. The arc erosion of Ag?4%SnO2 contact materials was tested, the arc duration and mass loss before and after arc erosion were determined, the surface morphologies and compositions of Ag?4%SnO2 contact materials after arc erosion were characterized, and the arc erosion mechanism of AgSnO2 contact materials was discussed. The results show that fine SnO2 particle is beneficial for the improvement of the relative density and hardness, but decreases the electrical conductivity. With the decrease of SnO2 particle size, Ag?4%SnO2contact material presents shorter arc duration, less mass loss, larger erosion area and shallower arc erosion pits.
文摘The significance of soil mineral properties and secondary environmental conditions such as pH, temperature, ionic strength and time in the partitioning of eight selected polychlorinated biphenyl(PCB) congeners between aqueous solution and soil particles with different grain sizes was studied. The mineral properties of a model soil sample were determined, and Brunauer–Emmett–Teller(BET) adsorption–desorption isotherms were employed to observe the surface characteristics of the individual modeled soil particles.Batch adsorption experiments were conducted to determine the sorption of PCBs onto soil particles of different sizes. The results revealed that the sorption of PCB congeners onto the soil was dependent on the amount of soil organic matter, surface area, and pore size distribution of the various individual soil particles. Low pH favored the sorption of PCBs,with maximum sorption occurring between pH 6.5 and 7.5 with an equilibration period of 8 hr.Changes in the ionic strength were found to be less significant. Low temperature favored the sorption of PCBs onto the soil compared to high temperatures. Thermodynamic studies showed that the partition coefficient(K_d) decreased with increasing temperature, and negative and low values of ΔH° indicated an exothermic physisorption process. The data generated is critical and will help in further understanding remediation and cleanup strategies for polluted water.
