The scratching mechanism of polycrystallineγ-TiAl alloy was investigated at the atomic scale using the molecular dynamics method,with a focus on the influence of different grain sizes.The analysis encompassed tribolo...The scratching mechanism of polycrystallineγ-TiAl alloy was investigated at the atomic scale using the molecular dynamics method,with a focus on the influence of different grain sizes.The analysis encompassed tribological characteristics,scratch morphology,subsurface defect distribution,temperature variations,and stress states during the scratching process.The findings indicate that the scratch force,number of recovered atoms,and pile-up height exhibit abrupt changes when the critical size is 9.41 nm due to the influence of the inverse Hall-Petch effect.Variations in the number of grain boundaries and randomness of grain orientation result in different accumulation patterns on the scratch surface.Notably,single crystal materials and those with 3.73 nm in grain size display more regular surface morphology.Furthermore,smaller grain size leads to an increase in average coefficient of friction,removed atoms number,and wear rate.While it also causes higher temperatures with a larger range of distributions.Due to the barrier effect of grain boundaries,smaller grains exhibit reduced microscopic defects.Additionally,average von Mises stress and hydrostatic compressive stress at the indenter tip decrease as grain size decreases owing to grain boundary obstruction.展开更多
Liposomes serve as critical carriers for drugs and vaccines,with their biological effects influenced by their size.The microfluidic method,renowned for its precise control,reproducibility,and scalability,has been wide...Liposomes serve as critical carriers for drugs and vaccines,with their biological effects influenced by their size.The microfluidic method,renowned for its precise control,reproducibility,and scalability,has been widely employed for liposome preparation.Although some studies have explored factors affecting liposomal size in microfluidic processes,most focus on small-sized liposomes,predominantly through experimental data analysis.However,the production of larger liposomes,which are equally significant,remains underexplored.In this work,we thoroughly investigate multiple variables influencing liposome size during microfluidic preparation and develop a machine learning(ML)model capable of accurately predicting liposomal size.Experimental validation was conducted using a staggered herringbone micromixer(SHM)chip.Our findings reveal that most investigated variables significantly influence liposomal size,often interrelating in complex ways.We evaluated the predictive performance of several widely-used ML algorithms,including ensemble methods,through cross-validation(CV)for both lipo-some size and polydispersity index(PDI).A standalone dataset was experimentally validated to assess the accuracy of the ML predictions,with results indicating that ensemble algorithms provided the most reliable predictions.Specifically,gradient boosting was selected for size prediction,while random forest was employed for PDI prediction.We successfully produced uniform large(600 nm)and small(100 nm)liposomes using the optimised experimental conditions derived from the ML models.In conclusion,this study presents a robust methodology that enables precise control over liposome size distribution,of-fering valuable insights for medicinal research applications.展开更多
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
A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which ca...A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which can accurately describe the strain and stress states in IF.Based on strain analysis,the model can predict the material thickness distribution and neck height after IF.By considering contact area,strain characteristics,material thickness changes,and friction,the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF.In addition,an IF experiment involving different tool diameters,flanging diameters,and opening hole diameters is conducted.On the basis of the experimental strain paths,the strain characteristics of different deformation zones are studied,and the stable strain ratio is quantitatively described through two dimensionless parameters:relative tool diameter and relative hole diameter.Then,the changing of material thickness and forming force in IF,and the variation of minimum material thickness,neck height,maximum axial forming force,and maximum horizontal forming force with flanging parameters are studied,and the reliability of the analytical model is verified in this process.Finally,the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained.展开更多
Large size titanium alloy parts are widely used in aerospace.However,they are difficult to manufacture using mechanical cutting technology because of severe tool wear.Electrochemical jet machining is a promising techn...Large size titanium alloy parts are widely used in aerospace.However,they are difficult to manufacture using mechanical cutting technology because of severe tool wear.Electrochemical jet machining is a promising technology to achieve high efficiency,because it has high machining flexibility and no machining tool wear.However,reports on the macro electrochemical jet machining of large size titanium alloy parts are very scarce,because it is difficult to achieve effective constraint of the flow field in macro electrochemical jet machining.In addition,titanium alloy is very sensitive to fluctuation of the flow field,and a turbulent flow field would lead to serious stray corrosion.This paper reports a series of investigations of the electrochemical jet machining of titanium alloy parts.Based on the flow analysis and experiments,the machining flow field was effectively constrained.TB6 titanium alloy part with a perimeter of one meter was machined.The machined surface was smooth with no obvious machining defects.The machining process was particularly stable with no obvious spark discharge.The research provides a reference for the application of electrochemical jet machining technology to achieve large allowance material removal in the machining of large titanium alloy parts.展开更多
The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing gr...The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing grain size and phase distribution.Results show that the addition of GPLs leads to significant grain refinement of WC and the more uniform distribution of WC grain size.When the content of GPLs is 0.10wt%,the average WC grain size in the cemented carbide is 0.39μm,which is 32%lower than that in WC-Co.However,the shape of WC grains is almost unaffected,while the mean free path of Co decreases.The grain refinement of WC is attributed to the homogeneous distribution of GPLs between WC/WC and WC/Co grain boundaries,which hinders the solution and precipitation process of WC in liquid phase Co,as well as the migration and growth of WC grains.Additionally,GPLs can serve as heat transfer plates in materials to improve cooling efficiency,thus inhibiting the growth of WC grain.展开更多
The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compressio...The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.展开更多
A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with ...A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.展开更多
The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size,distribution and morphology of graphene.However,the effect of the graphene size/distribution on the mechan...The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size,distribution and morphology of graphene.However,the effect of the graphene size/distribution on the mechanical properties and related strengthening mechanisms has not been fully elucidated.Herein,under the same volume fraction and distribution conditions of graphene,molecular dynamics simulations were used to investigate the effect of graphene sheet size on the hardness and deformation behavior of Cu/graphene composites under complex stress field.Two models of pure single crystalline Cu and graphene fully covered Cu matrix composite were constructed for comparison.The results show that the strengthening effect changes with varying the graphene sheet size.Besides the graphene dislocation blocking effect and the load-bearing effect,the deformation mechanisms change from stacking fault tetrahedron,dislocation bypassing and dislocation cutting to dislocation nucleation in turn with decreasing the graphene sheet size.The hardness of Cu/graphene composite,with the graphene sheet not completely covering the metal matrix,can even be higher than that of the fully covered composite.The extra strengthening mechanisms of dislocation bypassing mechanism and the stacking fault tetrahedra pinning dislocation mechanism contribute to the increase in hardness.展开更多
Constructed Wetlands (CWs) are currently one of the most promising techniques for wastewater treatment, having demonstrated their effectiveness. However, the choice of substrate particle size is critical to the smooth...Constructed Wetlands (CWs) are currently one of the most promising techniques for wastewater treatment, having demonstrated their effectiveness. However, the choice of substrate particle size is critical to the smooth operation of the process, as hydrodynamic constraints require a coarse particle size, whereas wastewater treatment recommends a fine particle size. This study investigates the suitability of laterite and shale as substrates of different sizes (1 - 3, 3 - 5 and 5 - 8 mm) in CWs for domestic wastewater treatment. The study was carried out in an experimental pilot plant consisting of 12 parallelepiped beds (C × C = 0.4 × 0.4 m2;H = 0.6 m) filled from bottom to top with 0.1 m of gravel and 0.4 m of shale or laterite of different grain sizes with two replications. During the six months of operation, plant biomass and stem diameter of Pennisetum purpureum used as vegetation in the CWs were determined. Raw and treated water were also sampled and analyzed for pollutants, including chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total Kjedahl nitrogen (TKN), total phosphorus (TP), and total suspended solids (TSS), using International Organization for Standardization (ISO) analytical methods. P. purpureum developed much better in the CW beds lined with shale;plant biomass ranged from 13.8 to 14.7 kg/m2 and from 11.2 to 12.5 kg/m2 in the beds lined with shale and laterite, respectively, as did stump diameter, which ranged from 15.5 to 16.1 cm and from 11.10 to 12.7 cm, respectively. However, the highest values for biomass and stump diameter for each material were obtained in the beds lined with 1 - 3 mm geomaterials. Pollutant removal efficiencies were highest in the CWs lined with laterite and shale of 1 - 3 mm grain size (76.9% - 83% COD, 78% - 84.7% BOD5, 55.5% - 72.2% TKN, 58.4% - 72.4% TP, 78.1% - 80.2% TSS), with the highest values recorded in the shale-lined beds. However, the 3 - 5 mm grain size of both materials provided quality filtrates (140 - 174 mg/L COD, 78.5 - 94.8 mg/L BOD5, 4.6 - 5.7 mg/L TP) in line with local wastewater discharge levels. This size of geomaterials appears to be suitable for optimization purposes, although further work with these materials, such as increasing the depth of the wetland, is required to improve the level of NTK and TSS discharge.展开更多
Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are ess...Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.展开更多
To the Editor:Thymic carcinoma is a highly aggressive subtype of thymomas,accounting for 1%of thymic malignancies.It predominantly(80%)manifests in the anterosuperior mediastinum[1].Nevertheless,the occurrence of extr...To the Editor:Thymic carcinoma is a highly aggressive subtype of thymomas,accounting for 1%of thymic malignancies.It predominantly(80%)manifests in the anterosuperior mediastinum[1].Nevertheless,the occurrence of extrathoracic metastases,particularly liver metastases,is uncommon.The clinical manifestation of thymic carcinoma accompanied by liver metastases is characterized by ambiguous and nonspecific symptoms.Consequently,it is challenging to ascertain.展开更多
This study investigates the size characteristics and related temporal variations of tropical cyclones(TCs)over the Western North Pacific(WNP)and those affecting East China(EC)using Joint Typhoon Warning Center(JTWC)da...This study investigates the size characteristics and related temporal variations of tropical cyclones(TCs)over the Western North Pacific(WNP)and those affecting East China(EC)using Joint Typhoon Warning Center(JTWC)data during 2001-20.The average size of EC TCs is found to be similar to that over the WNP.Furthermore,the annual maximum lifetime maximum size(LMS)of EC TCs shows a statistically significant increasing trend,implying a more severe impact on the EC region.Composite analyses of intensity and size variation over the entire lifetime of TCs,before and after re-curvature,and before and after rapid intensification(RI),show that there are significant differences between them in some key areas:(1)The intensity begins to rapidly decrease after the TC has reached its highest intensity,but the size remains quasi-constant;(2)When a TC recurves south of 15°N or north of 30°N,the variation trend for both intensity and size are broadly similar before and after curvature,but their variation trends are opposite when the recurvature occurs between 15°-30°N;(3)After RI,the intensity reaches its peak value within 24 h,whereas the size reaches its LMS after30-48 h.A significant correlation is also found between the rate of change in intensity and that of size during the development stage,with a correlation coefficient of 0.67 and 0.73 for TCs in the WNP and EC,respectively.However,no significant correlation exists during the weakening stage.展开更多
Plant height and grain size are the most important factors determining rice yield.Here,in the rice mutant small plant and organ size1(spos1)with reduced plant height and small grain,T-DNA insertion revealed that the m...Plant height and grain size are the most important factors determining rice yield.Here,in the rice mutant small plant and organ size1(spos1)with reduced plant height and small grain,T-DNA insertion revealed that the mutant phenotype was caused by increased expression of of OsSAUR23 and OsRR9,which participate in auxin and cytokinin signal transduction,respectively.Knock out of OsSAUR23 increased rice grain size but did not change plant height.Double knock out of OsRR9 and its replicated gene OsRR10 also brought similar effects on rice as that of OsSAUR23 knock-out.Genetic analysis suggested that OsSAUR23 was a major recessive gene and OsRR9 was a minor dominant gene,which co-regulated the phenotype of spos1.Compared with wild type,auxin synthesis and signaling,cytokinin homeostasis and signaling,as well as GA,ABA and BR metabolism and signaling were regulated in seedlings of spos1.The increased concentrations of IAA and cytokinins in the mutant suggest hormonal co-regulation of rice organ size.展开更多
Understanding the factors that control typhoon rainfall distribution is critical for improving rainfall forecasting,especially for landfall typhoons. This study investigated the impact of typhoon size on rainfall char...Understanding the factors that control typhoon rainfall distribution is critical for improving rainfall forecasting,especially for landfall typhoons. This study investigated the impact of typhoon size on rainfall characteristics at landfall in eastern coast of China. Typhoons Ampil(2018) and Rumbia(2018), which had similar intensities, were investigated to explore the connection between storm size and rainfall. The larger cyclonic wind field in Typhoon Rumbia led to greater vorticity and broader convergence compared to Typhoon Ampil, along with an ascending region outside the eyewall, which promoted more vigorous rainbands. Rumbia′s larger size exhibited greater outer-core radial vorticity advection relative to Ampil. This maintained its extensive outer-core wind field and intensified outer rainband development. Consequently,Rumbia generated more extensive and prolonged rainfall post-landfall compared to Ampil. A composite analysis of typhoons making landfall in eastern China(2001-2021) further examines the statistical correlation between typhoon size and rainfall distribution. Results indicate that larger typhoons are more likely to generate heavier and more spatially extensive rainfall in regions beyond their eyewalls. These findings highlight that typhoon size significantly regulates rainfall evolution during landfall, underscoring the necessity of incorporating this parameter into operational rainfall forecasting models for landfalling typhoons.展开更多
Magnesium–zinc–calcium alloy has emerged as a key focus in the field of medical degradable materials due to its excellent biodegradability and osteoconductive properties.Grain size is crucial for the physicochemical...Magnesium–zinc–calcium alloy has emerged as a key focus in the field of medical degradable materials due to its excellent biodegradability and osteoconductive properties.Grain size is crucial for the physicochemical and biological properties of Mg–Zn–Ca alloy,but it has not been clearly elucidated yet.In this research,Mg-1Zn-0.2Ca-1.0MgO with different grain sizes were prepared to investigate the effect of grain size on the physicochemical properties,corrosion resistance,and osteogenesis.The results indicate that grain refinement improves the mechanical properties and enhances the corrosion resistance of the alloy.The bone surface area to bone volume ratio,bone surface area to tissue volume ratio,and bone volume fraction of the 0.6–0.8μm group show significantly better performance compared to the 2–3μm group and 5–6μm group,indicating that grain refinement can promote the osseointegration between alloy and natural bone.This may be achieved by enhancing the metabolic intensity of alanine,aspartate,glutamate,serine,and glycine around the implant.This work illustrates the effect of grain size on the osseointegration of bone implants and provides a reference for optimizing the properties of bone implant alloys.展开更多
The FW2.2-like(FWL)gene family has been extensively studied across multiple species,demonstrating conserved functions among specific members in organ development,particularly in fruit size regulation.For species with ...The FW2.2-like(FWL)gene family has been extensively studied across multiple species,demonstrating conserved functions among specific members in organ development,particularly in fruit size regulation.For species with limited research foundations,such as Chinese jujube,analyzing this gene family is an effective approach to identify candidate genes for fruit size.This study identified twenty ZjFWL genes and comprehensively analyzed their chromosomal distribution,phylogenetic relationships,gene structure,evolutionary dynamics,expression patterns,and cis-acting elements in their promoters.Natural variation analysis of the ZjFWL10 sequence identified a significant correlation between a seven-base pair deletion in the conserved domain and jujube fruit size.To validate the functional implications of the seven-base pair deletion genotype,heterologous overexpression experiments were conducted in tomatoes,generating three overexpression lines.Comparative analysis with the wild-type demonstrated a significant reduction in fruit size and a notable increase in plant height in the overexpressed lines.This gene may play a critical role in regulating nutrient partitioning in jujube,ultimately affecting fruit size.These findings advance our understanding of fruit size regulation mechanisms and offer valuable insights for genetic improvement strategies targeting jujube fruit size.展开更多
Silicon carbide offers distinct advantages in the field of power electronic devices.However,manufacturing processes remain a significant barrier to its widespread adoption.Polycrystalline SiC is less expensive and eas...Silicon carbide offers distinct advantages in the field of power electronic devices.However,manufacturing processes remain a significant barrier to its widespread adoption.Polycrystalline SiC is less expensive and easier to produce than single crystal.But stabilizing and controlling its performance are critical challenges that must be addressed urgently.Due to its material properties and excellent performance in applications,3C-SiC is gaining increasing attention in research.This article presents the electrical and material properties of a series of polycrystalline 3C-SiC samples and investigates their interrelationship.The samples were examined using TEM,which confirmed their polycrystalline structure.Combined with XRD and Raman spectroscopy,the grain orientations within the samples were analyzed,and the presence of stress was verified.EBSD was employed to statistically examine the grain structure and size across samples.For samples with similar doping levels,grain size is the most influential factor in determining electrical characteristics.Further EBSD measurements reveal the relationship between resistivity and grain size as log(ρ)=-1.93+8.67/d.These findings provide a foundation for the quantitative control and application of polycrystalline 3C-SiC.This work offers theoretical evidence for optimizing the performance tuning of 3C-SiC ceramics and enhancing their effectiveness in electronic applications.展开更多
Droughts have caused tree growth decline and high tree mortality across temperate forests,however,how to manage planted forests to alleviate drought stress is still challenging.We used tree-ring and forest inventory d...Droughts have caused tree growth decline and high tree mortality across temperate forests,however,how to manage planted forests to alleviate drought stress is still challenging.We used tree-ring and forest inventory data from different density stands to investigate how competition,tree diameter at breast height(DBH),tree age,and their interactions influence drought sensitivity and resistance for three widely-distributed and planted conifer species(Larix principis-rupprechtii,Picea meyeri,and Pinus sylvestris var.mongolica).Our results showed that the drought sensitivity of the three species was influenced by competition,tree size,and their interactions.Large L.principis-rupprechtii trees were particularly sensitive to drought during the growing season in medium to high-density stands,while the growth of large P.sylvestris var.mongolica was most affected by precipitation at low to medium density stands.Drought resistance of L.principis-rupprechtii trees decreased as tree size increased.Large L.principis-rupprechtii trees had lower drought resistance than small trees in all stands.Drought resistance of large P.meyeri trees exhibited high resistance to drought only in high-density stands.However,drought resistance of P.sylvestris var.mongolica trees was affected by tree size,competition,and their interactions.These results indicated that targeted silvicultural interventions,such as thinning,can be implemented to enhance drought resistance specifically for large L.principis-rupprechtii trees and small P.sylvestris var.mongolica trees in medium and high competition stands,and small P.meyeri trees in high competition stands.Our results highlight that properly conducted thinning can in some cases enhance growth resistance to droughts,depending on stand density,tree size,and tree species.展开更多
Developing the railway transport sector is a challenging scientific,economic and social research topic starting with ensuring human security.The main topic that should be developed in that sense is the ballast stabili...Developing the railway transport sector is a challenging scientific,economic and social research topic starting with ensuring human security.The main topic that should be developed in that sense is the ballast stability and dynamical behaviour under external loading and environmental changes.This paper investigates the effect of particle size distribution and normal pressure on the mechanical response of a ballast bed.Grading curves of ballast layers with different sizes are illustrated to discuss their strength behaviour under various strains to deduce the significant effect on the direct shear performance of the ballast layer.Direct shear tests with different Particle Size Distribution(PSD)were reproduced using the Discrete Element Method(DEM).It is noticed that when the number of small-sized ballast increases,the shear strength and the friction angle increase to varying degrees under different normal pressures,with an average increase of 27%and 8%,respectively.When the number of large-sized ballast decreases,the shear strength and the friction angle decrease to varying degrees under different normal pressures,with an average decrease of 6%and 3%,respectively.展开更多
基金National Natural Science Foundation of China(52065036,52365018)Natural Science Foundation of Gansu(23JRRA760)+1 种基金Hongliu Outstanding Youth Foundation of Lanzhou University of TechnologyChina Postdoctoral Science Foundation(2023M733583)。
文摘The scratching mechanism of polycrystallineγ-TiAl alloy was investigated at the atomic scale using the molecular dynamics method,with a focus on the influence of different grain sizes.The analysis encompassed tribological characteristics,scratch morphology,subsurface defect distribution,temperature variations,and stress states during the scratching process.The findings indicate that the scratch force,number of recovered atoms,and pile-up height exhibit abrupt changes when the critical size is 9.41 nm due to the influence of the inverse Hall-Petch effect.Variations in the number of grain boundaries and randomness of grain orientation result in different accumulation patterns on the scratch surface.Notably,single crystal materials and those with 3.73 nm in grain size display more regular surface morphology.Furthermore,smaller grain size leads to an increase in average coefficient of friction,removed atoms number,and wear rate.While it also causes higher temperatures with a larger range of distributions.Due to the barrier effect of grain boundaries,smaller grains exhibit reduced microscopic defects.Additionally,average von Mises stress and hydrostatic compressive stress at the indenter tip decrease as grain size decreases owing to grain boundary obstruction.
基金supported by the National Key Research and Development Plan of the Ministry of Science and Technology,China(Grant No.:2022YFE0125300)the National Natural Science Foundation of China(Grant No:81690262)+2 种基金the National Science and Technology Major Project,China(Grant No.:2017ZX09201004-021)the Open Project of National facility for Translational Medicine(Shanghai),China(Grant No.:TMSK-2021-104)Shanghai Jiao Tong University STAR Grant,China(Grant Nos.:YG2022ZD024 and YG2022QN111).
文摘Liposomes serve as critical carriers for drugs and vaccines,with their biological effects influenced by their size.The microfluidic method,renowned for its precise control,reproducibility,and scalability,has been widely employed for liposome preparation.Although some studies have explored factors affecting liposomal size in microfluidic processes,most focus on small-sized liposomes,predominantly through experimental data analysis.However,the production of larger liposomes,which are equally significant,remains underexplored.In this work,we thoroughly investigate multiple variables influencing liposome size during microfluidic preparation and develop a machine learning(ML)model capable of accurately predicting liposomal size.Experimental validation was conducted using a staggered herringbone micromixer(SHM)chip.Our findings reveal that most investigated variables significantly influence liposomal size,often interrelating in complex ways.We evaluated the predictive performance of several widely-used ML algorithms,including ensemble methods,through cross-validation(CV)for both lipo-some size and polydispersity index(PDI).A standalone dataset was experimentally validated to assess the accuracy of the ML predictions,with results indicating that ensemble algorithms provided the most reliable predictions.Specifically,gradient boosting was selected for size prediction,while random forest was employed for PDI prediction.We successfully produced uniform large(600 nm)and small(100 nm)liposomes using the optimised experimental conditions derived from the ML models.In conclusion,this study presents a robust methodology that enables precise control over liposome size distribution,of-fering valuable insights for medicinal research applications.
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 in part by financial support from the National Key R&D Program of China(No.2023YFB3407003)the National Natural Science Foundation of China(No.52375378).
文摘A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which can accurately describe the strain and stress states in IF.Based on strain analysis,the model can predict the material thickness distribution and neck height after IF.By considering contact area,strain characteristics,material thickness changes,and friction,the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF.In addition,an IF experiment involving different tool diameters,flanging diameters,and opening hole diameters is conducted.On the basis of the experimental strain paths,the strain characteristics of different deformation zones are studied,and the stable strain ratio is quantitatively described through two dimensionless parameters:relative tool diameter and relative hole diameter.Then,the changing of material thickness and forming force in IF,and the variation of minimum material thickness,neck height,maximum axial forming force,and maximum horizontal forming force with flanging parameters are studied,and the reliability of the analytical model is verified in this process.Finally,the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained.
基金the National Natural Science Foundation of China(No.52205468)China Postdoctoral Science Foundation(No.2022M710061 and No.2023T160277)Natural Science Foundation of Jiangsu Province(No.BK20210755)。
文摘Large size titanium alloy parts are widely used in aerospace.However,they are difficult to manufacture using mechanical cutting technology because of severe tool wear.Electrochemical jet machining is a promising technology to achieve high efficiency,because it has high machining flexibility and no machining tool wear.However,reports on the macro electrochemical jet machining of large size titanium alloy parts are very scarce,because it is difficult to achieve effective constraint of the flow field in macro electrochemical jet machining.In addition,titanium alloy is very sensitive to fluctuation of the flow field,and a turbulent flow field would lead to serious stray corrosion.This paper reports a series of investigations of the electrochemical jet machining of titanium alloy parts.Based on the flow analysis and experiments,the machining flow field was effectively constrained.TB6 titanium alloy part with a perimeter of one meter was machined.The machined surface was smooth with no obvious machining defects.The machining process was particularly stable with no obvious spark discharge.The research provides a reference for the application of electrochemical jet machining technology to achieve large allowance material removal in the machining of large titanium alloy parts.
基金National Natural Science Foundation of China(51572224)Guangdong Young Creative Talents(2023KQNCX039)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2023A1515110551)Innovative Team in Higher Educational Institutions of Guangdong Province(2020KCXTD039)2023 Lingnan Normal College Students Innovation and Entrepreneurship Training Program(1742)。
文摘The influence of graphene platelets(GPLs)on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated.The role of GPLs in refining WC grains was explored by characterizing grain size and phase distribution.Results show that the addition of GPLs leads to significant grain refinement of WC and the more uniform distribution of WC grain size.When the content of GPLs is 0.10wt%,the average WC grain size in the cemented carbide is 0.39μm,which is 32%lower than that in WC-Co.However,the shape of WC grains is almost unaffected,while the mean free path of Co decreases.The grain refinement of WC is attributed to the homogeneous distribution of GPLs between WC/WC and WC/Co grain boundaries,which hinders the solution and precipitation process of WC in liquid phase Co,as well as the migration and growth of WC grains.Additionally,GPLs can serve as heat transfer plates in materials to improve cooling efficiency,thus inhibiting the growth of WC grain.
基金financially supported by the National Natural Science Foundation of China(Nos.52174092,51904290,and 52374147)the Natural Science Foundation of Jiangsu Province,China(No.BK20220157)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.2022YCPY0202)the National Key Research and Development Program of China(No.2023YFC3804204)the Major Program of Xinjiang Uygur Autonomous Region S cience and Technology(No.2023A01002)。
文摘The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.
文摘A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.
基金Foundation of Northwest Institute for Nonferrous Metal Research(ZZXJ2203)Capital Projects of Financial Department of Shaanxi Province(YK22C-12)+3 种基金Innovation Capability Support Plan in Shaanxi Province(2023KJXX-083)Key Research and Development Projects of Shaanxi Province(2024GXYBXM-351,2024GX-YBXM-356)National Natural Science Foundation of China(62204207,12204383)Xi'an Postdoctoral Innovation Base Funding Program。
文摘The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size,distribution and morphology of graphene.However,the effect of the graphene size/distribution on the mechanical properties and related strengthening mechanisms has not been fully elucidated.Herein,under the same volume fraction and distribution conditions of graphene,molecular dynamics simulations were used to investigate the effect of graphene sheet size on the hardness and deformation behavior of Cu/graphene composites under complex stress field.Two models of pure single crystalline Cu and graphene fully covered Cu matrix composite were constructed for comparison.The results show that the strengthening effect changes with varying the graphene sheet size.Besides the graphene dislocation blocking effect and the load-bearing effect,the deformation mechanisms change from stacking fault tetrahedron,dislocation bypassing and dislocation cutting to dislocation nucleation in turn with decreasing the graphene sheet size.The hardness of Cu/graphene composite,with the graphene sheet not completely covering the metal matrix,can even be higher than that of the fully covered composite.The extra strengthening mechanisms of dislocation bypassing mechanism and the stacking fault tetrahedra pinning dislocation mechanism contribute to the increase in hardness.
文摘Constructed Wetlands (CWs) are currently one of the most promising techniques for wastewater treatment, having demonstrated their effectiveness. However, the choice of substrate particle size is critical to the smooth operation of the process, as hydrodynamic constraints require a coarse particle size, whereas wastewater treatment recommends a fine particle size. This study investigates the suitability of laterite and shale as substrates of different sizes (1 - 3, 3 - 5 and 5 - 8 mm) in CWs for domestic wastewater treatment. The study was carried out in an experimental pilot plant consisting of 12 parallelepiped beds (C × C = 0.4 × 0.4 m2;H = 0.6 m) filled from bottom to top with 0.1 m of gravel and 0.4 m of shale or laterite of different grain sizes with two replications. During the six months of operation, plant biomass and stem diameter of Pennisetum purpureum used as vegetation in the CWs were determined. Raw and treated water were also sampled and analyzed for pollutants, including chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total Kjedahl nitrogen (TKN), total phosphorus (TP), and total suspended solids (TSS), using International Organization for Standardization (ISO) analytical methods. P. purpureum developed much better in the CW beds lined with shale;plant biomass ranged from 13.8 to 14.7 kg/m2 and from 11.2 to 12.5 kg/m2 in the beds lined with shale and laterite, respectively, as did stump diameter, which ranged from 15.5 to 16.1 cm and from 11.10 to 12.7 cm, respectively. However, the highest values for biomass and stump diameter for each material were obtained in the beds lined with 1 - 3 mm geomaterials. Pollutant removal efficiencies were highest in the CWs lined with laterite and shale of 1 - 3 mm grain size (76.9% - 83% COD, 78% - 84.7% BOD5, 55.5% - 72.2% TKN, 58.4% - 72.4% TP, 78.1% - 80.2% TSS), with the highest values recorded in the shale-lined beds. However, the 3 - 5 mm grain size of both materials provided quality filtrates (140 - 174 mg/L COD, 78.5 - 94.8 mg/L BOD5, 4.6 - 5.7 mg/L TP) in line with local wastewater discharge levels. This size of geomaterials appears to be suitable for optimization purposes, although further work with these materials, such as increasing the depth of the wetland, is required to improve the level of NTK and TSS discharge.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406000 and 2022YFA1403800)the National Natural Science Foundation of China(Grant Nos.12474002,22171283,22203031,12434005,12204515,and 12074175)support of the Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)。
文摘Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.
基金supported by a grant from the National Natural Science Foundation of China(No.82202974)。
文摘To the Editor:Thymic carcinoma is a highly aggressive subtype of thymomas,accounting for 1%of thymic malignancies.It predominantly(80%)manifests in the anterosuperior mediastinum[1].Nevertheless,the occurrence of extrathoracic metastases,particularly liver metastases,is uncommon.The clinical manifestation of thymic carcinoma accompanied by liver metastases is characterized by ambiguous and nonspecific symptoms.Consequently,it is challenging to ascertain.
基金supported by National Natural Science Foundation of China under(Grant No.U2142206)the Shanghai Natural Science Foundation(21ZR1477300)+1 种基金Shanghai Science and Technology Commission Project(23DZ1204701)National Natural Science Foundation of China(Grant No.42075056)。
文摘This study investigates the size characteristics and related temporal variations of tropical cyclones(TCs)over the Western North Pacific(WNP)and those affecting East China(EC)using Joint Typhoon Warning Center(JTWC)data during 2001-20.The average size of EC TCs is found to be similar to that over the WNP.Furthermore,the annual maximum lifetime maximum size(LMS)of EC TCs shows a statistically significant increasing trend,implying a more severe impact on the EC region.Composite analyses of intensity and size variation over the entire lifetime of TCs,before and after re-curvature,and before and after rapid intensification(RI),show that there are significant differences between them in some key areas:(1)The intensity begins to rapidly decrease after the TC has reached its highest intensity,but the size remains quasi-constant;(2)When a TC recurves south of 15°N or north of 30°N,the variation trend for both intensity and size are broadly similar before and after curvature,but their variation trends are opposite when the recurvature occurs between 15°-30°N;(3)After RI,the intensity reaches its peak value within 24 h,whereas the size reaches its LMS after30-48 h.A significant correlation is also found between the rate of change in intensity and that of size during the development stage,with a correlation coefficient of 0.67 and 0.73 for TCs in the WNP and EC,respectively.However,no significant correlation exists during the weakening stage.
基金supported by the CAAS Science and Technology Innovation Program(2060302-2).
文摘Plant height and grain size are the most important factors determining rice yield.Here,in the rice mutant small plant and organ size1(spos1)with reduced plant height and small grain,T-DNA insertion revealed that the mutant phenotype was caused by increased expression of of OsSAUR23 and OsRR9,which participate in auxin and cytokinin signal transduction,respectively.Knock out of OsSAUR23 increased rice grain size but did not change plant height.Double knock out of OsRR9 and its replicated gene OsRR10 also brought similar effects on rice as that of OsSAUR23 knock-out.Genetic analysis suggested that OsSAUR23 was a major recessive gene and OsRR9 was a minor dominant gene,which co-regulated the phenotype of spos1.Compared with wild type,auxin synthesis and signaling,cytokinin homeostasis and signaling,as well as GA,ABA and BR metabolism and signaling were regulated in seedlings of spos1.The increased concentrations of IAA and cytokinins in the mutant suggest hormonal co-regulation of rice organ size.
基金National Natural Science Foundation of China(42375012)China Meteorological Administration Foundation(CXFZ2025J023)。
文摘Understanding the factors that control typhoon rainfall distribution is critical for improving rainfall forecasting,especially for landfall typhoons. This study investigated the impact of typhoon size on rainfall characteristics at landfall in eastern coast of China. Typhoons Ampil(2018) and Rumbia(2018), which had similar intensities, were investigated to explore the connection between storm size and rainfall. The larger cyclonic wind field in Typhoon Rumbia led to greater vorticity and broader convergence compared to Typhoon Ampil, along with an ascending region outside the eyewall, which promoted more vigorous rainbands. Rumbia′s larger size exhibited greater outer-core radial vorticity advection relative to Ampil. This maintained its extensive outer-core wind field and intensified outer rainband development. Consequently,Rumbia generated more extensive and prolonged rainfall post-landfall compared to Ampil. A composite analysis of typhoons making landfall in eastern China(2001-2021) further examines the statistical correlation between typhoon size and rainfall distribution. Results indicate that larger typhoons are more likely to generate heavier and more spatially extensive rainfall in regions beyond their eyewalls. These findings highlight that typhoon size significantly regulates rainfall evolution during landfall, underscoring the necessity of incorporating this parameter into operational rainfall forecasting models for landfalling typhoons.
基金financially supported by the Foundation of Tianjin city of China(Nos.21JCYBJC00490 and 21JCQNJC01040)Science and Technology Project of Tianjin Municipal Health Commission(Nos.TJWJ2023MS023 and TJWJ2022MS027)+3 种基金the project of Tianjin Municipal Health Commission(No.2023168)the crosswise tasks of Tianjin Hospital of Integrated Chinese and Western Medicine(No.HXKY2020-0825)Cooperation Project for Basic Research of Beijing-Tianjin-Hebei(No.22JCZXJC00130)Science and technology project of Tianjin Municipal Health Commission(Nos.ZC20112 and KJ20131)。
文摘Magnesium–zinc–calcium alloy has emerged as a key focus in the field of medical degradable materials due to its excellent biodegradability and osteoconductive properties.Grain size is crucial for the physicochemical and biological properties of Mg–Zn–Ca alloy,but it has not been clearly elucidated yet.In this research,Mg-1Zn-0.2Ca-1.0MgO with different grain sizes were prepared to investigate the effect of grain size on the physicochemical properties,corrosion resistance,and osteogenesis.The results indicate that grain refinement improves the mechanical properties and enhances the corrosion resistance of the alloy.The bone surface area to bone volume ratio,bone surface area to tissue volume ratio,and bone volume fraction of the 0.6–0.8μm group show significantly better performance compared to the 2–3μm group and 5–6μm group,indicating that grain refinement can promote the osseointegration between alloy and natural bone.This may be achieved by enhancing the metabolic intensity of alanine,aspartate,glutamate,serine,and glycine around the implant.This work illustrates the effect of grain size on the osseointegration of bone implants and provides a reference for optimizing the properties of bone implant alloys.
基金supported by the National Natural Science Foundation of China(31800559)the National Key Research and Development Program of China(2022YFD2200404)+2 种基金the National XA Science and Technology Innovation Project,China(2022XACX1100)the Science and Technology Major Project of Guangxi,China(‘Guike’AB16380060)the central government guides local science and technology development project“Germplasm Innovation of Xinjiang Characteristic Fruit Tree”,and partly supported by the open funds of the National Key Laboratory for Germplasm Innovation&Utilization of Horticultural Crops,China.
文摘The FW2.2-like(FWL)gene family has been extensively studied across multiple species,demonstrating conserved functions among specific members in organ development,particularly in fruit size regulation.For species with limited research foundations,such as Chinese jujube,analyzing this gene family is an effective approach to identify candidate genes for fruit size.This study identified twenty ZjFWL genes and comprehensively analyzed their chromosomal distribution,phylogenetic relationships,gene structure,evolutionary dynamics,expression patterns,and cis-acting elements in their promoters.Natural variation analysis of the ZjFWL10 sequence identified a significant correlation between a seven-base pair deletion in the conserved domain and jujube fruit size.To validate the functional implications of the seven-base pair deletion genotype,heterologous overexpression experiments were conducted in tomatoes,generating three overexpression lines.Comparative analysis with the wild-type demonstrated a significant reduction in fruit size and a notable increase in plant height in the overexpressed lines.This gene may play a critical role in regulating nutrient partitioning in jujube,ultimately affecting fruit size.These findings advance our understanding of fruit size regulation mechanisms and offer valuable insights for genetic improvement strategies targeting jujube fruit size.
基金supported in part by the Major Science and Technology Innovation Project of Shandong Province under Grant 2022CXGC010103Taishan Scholars Program of Shandong Province under Grant tstp20231210。
文摘Silicon carbide offers distinct advantages in the field of power electronic devices.However,manufacturing processes remain a significant barrier to its widespread adoption.Polycrystalline SiC is less expensive and easier to produce than single crystal.But stabilizing and controlling its performance are critical challenges that must be addressed urgently.Due to its material properties and excellent performance in applications,3C-SiC is gaining increasing attention in research.This article presents the electrical and material properties of a series of polycrystalline 3C-SiC samples and investigates their interrelationship.The samples were examined using TEM,which confirmed their polycrystalline structure.Combined with XRD and Raman spectroscopy,the grain orientations within the samples were analyzed,and the presence of stress was verified.EBSD was employed to statistically examine the grain structure and size across samples.For samples with similar doping levels,grain size is the most influential factor in determining electrical characteristics.Further EBSD measurements reveal the relationship between resistivity and grain size as log(ρ)=-1.93+8.67/d.These findings provide a foundation for the quantitative control and application of polycrystalline 3C-SiC.This work offers theoretical evidence for optimizing the performance tuning of 3C-SiC ceramics and enhancing their effectiveness in electronic applications.
基金funded by State Key Research and Development Program of China(No.2023YFD2200401)S&T Program of Hebei(Nos.226Z6801G,22326807D)Talent Introduction Program in Hebei Agricultural University(No.YJ201918).
文摘Droughts have caused tree growth decline and high tree mortality across temperate forests,however,how to manage planted forests to alleviate drought stress is still challenging.We used tree-ring and forest inventory data from different density stands to investigate how competition,tree diameter at breast height(DBH),tree age,and their interactions influence drought sensitivity and resistance for three widely-distributed and planted conifer species(Larix principis-rupprechtii,Picea meyeri,and Pinus sylvestris var.mongolica).Our results showed that the drought sensitivity of the three species was influenced by competition,tree size,and their interactions.Large L.principis-rupprechtii trees were particularly sensitive to drought during the growing season in medium to high-density stands,while the growth of large P.sylvestris var.mongolica was most affected by precipitation at low to medium density stands.Drought resistance of L.principis-rupprechtii trees decreased as tree size increased.Large L.principis-rupprechtii trees had lower drought resistance than small trees in all stands.Drought resistance of large P.meyeri trees exhibited high resistance to drought only in high-density stands.However,drought resistance of P.sylvestris var.mongolica trees was affected by tree size,competition,and their interactions.These results indicated that targeted silvicultural interventions,such as thinning,can be implemented to enhance drought resistance specifically for large L.principis-rupprechtii trees and small P.sylvestris var.mongolica trees in medium and high competition stands,and small P.meyeri trees in high competition stands.Our results highlight that properly conducted thinning can in some cases enhance growth resistance to droughts,depending on stand density,tree size,and tree species.
基金"PSPC Régions n°2"("Projets Structurants des Pôles de Compétitivitéen région")funded by Conseil Régional Hauts-de-France and BPI.
文摘Developing the railway transport sector is a challenging scientific,economic and social research topic starting with ensuring human security.The main topic that should be developed in that sense is the ballast stability and dynamical behaviour under external loading and environmental changes.This paper investigates the effect of particle size distribution and normal pressure on the mechanical response of a ballast bed.Grading curves of ballast layers with different sizes are illustrated to discuss their strength behaviour under various strains to deduce the significant effect on the direct shear performance of the ballast layer.Direct shear tests with different Particle Size Distribution(PSD)were reproduced using the Discrete Element Method(DEM).It is noticed that when the number of small-sized ballast increases,the shear strength and the friction angle increase to varying degrees under different normal pressures,with an average increase of 27%and 8%,respectively.When the number of large-sized ballast decreases,the shear strength and the friction angle decrease to varying degrees under different normal pressures,with an average decrease of 6%and 3%,respectively.
