Foam concrete is widely used in engineering due to its lightweight and high porosity.Its compressive strength,a key performance indicator,is influenced by multiple factors,showing nonlinear variation.As compressive st...Foam concrete is widely used in engineering due to its lightweight and high porosity.Its compressive strength,a key performance indicator,is influenced by multiple factors,showing nonlinear variation.As compressive strength tests for foam concrete take a long time,a fast and accurate prediction method is needed.In recent years,machine learning has become a powerful tool for predicting the compressive strength of cement-based materials.However,existing studies often use a limited number of input parameters,and the prediction accuracy of machine learning models under the influence of multiple parameters and nonlinearity remains unclear.This study selects foam concrete density,water-to-cement ratio(W/C),supplementary cementitious material replacement rate(SCM),fine aggregate to binder ratio(FA/Binder),superplasticizer content(SP),and age of the concrete(Age)as input parameters,with compressive strength as the output.Five different machine learning models were compared,and sensitivity analysis,based on Shapley Additive Explanations(SHAP),was used to assess the contribution of each input parameter.The results show that Gaussian Process Regression(GPR)outperforms the other models,with R2,RMSE,MAE,and MAPE values of 0.95,1.6,0.81,and 0.2,respectively.It is because GPR,optimized through Bayesian methods,better fits complex nonlinear relationships,especially considering a large number of input parameters.Sensitivity analysis indicates that the influence of input parameters on compressive strength decreases in the following order:foam concrete density,W/C,Age,FA/Binder,SP,and SCM.展开更多
An abnormally high peak friction angle of Ottawa sand was observed in(National Aeronautics and Space Administration) NASA–(Mechanics of Granular Materials) MGM tests in microgravity conditions on the space shuttle. P...An abnormally high peak friction angle of Ottawa sand was observed in(National Aeronautics and Space Administration) NASA–(Mechanics of Granular Materials) MGM tests in microgravity conditions on the space shuttle. Previous investigations have been unsuccessful in providing a constitutive insight into this behavior of granular materials under extremely low effective stress conditions. Here, a recently proposed unified constitutive model for transient rheological behavior of sand and other granular materials is adopted for the analytical assessment of high peak friction angles. For the first time, this long-eluded behavior of sand is attributed to a hidden rheological transition mechanism, that is not only rate-sensitive, but also pressure-sensitive. The NASA–MGM microgravity conditions show that shear-tests of sand can be performed under abnormally low confining stress conditions. The pressure-sensitive behavior of granular shearing that is previously ignored is studied based on the μ(I) rheology and its variations. Comparisons between the model and the NASA microgravity tests demonstrate a high degree of agreement. The research is highly valid for pressure-sensitive and rate-dependent problems that occur during earthquakes, landslides, and space exploration.展开更多
With the rapid development of artificial intelligence,magnetocaloric materials as well as other materials are being developed with increased efficiency and enhanced performance.However,most studies do not take phase t...With the rapid development of artificial intelligence,magnetocaloric materials as well as other materials are being developed with increased efficiency and enhanced performance.However,most studies do not take phase transitions into account,and as a result,the predictions are usually not accurate enough.In this context,we have established an explicable relationship between alloy compositions and phase transition by feature imputation.A facile machine learning is proposed to screen candidate NiMn-based Heusler alloys with desired magnetic entropy change and magnetic transition temperature with a high accuracy R^(2)≈0.98.As expected,the measured properties of prepared NiMn-based alloys,including phase transition type,magnetic entropy changes and transition temperature,are all in good agreement with the ML predictions.As well as being the first to demonstrate an explicable relationship between alloy compositions,phase transitions and magnetocaloric properties,our proposed ML model is highly predictive and interpretable,which can provide a strong theoretical foundation for identifying high-performance magnetocaloric materials in the future.展开更多
We have designed,assembled,and tested a 4-MA,60-ns fast linear transformer driver(LTD),which is the first operating generator featuring multiple LTD modules connected in parallel.The LTD-based accelerator comprises si...We have designed,assembled,and tested a 4-MA,60-ns fast linear transformer driver(LTD),which is the first operating generator featuring multiple LTD modules connected in parallel.The LTD-based accelerator comprises six modules in parallel,each of which has ten-stage cavities stacked in series.The six LTD modules are connected to a water tank of diameter 6 m via a 3-m-long impedance-matched deionized waterinsulated coaxial transmission line.In the water tank,the electrical pulses are transmitted down by six horizontal tri-plate transmission lines.A 2.1-m-diameter two-level vacuum insulator stack is utilized to separate the deionized water region from the vacuum region.In the vacuum,the currents are further transported downstream by a two-level magnetically insulated transmission-line and then converged through four post-hole convolutes.Plasma radiation loads or bremsstrahlung electron beam diodes serve as loads that are expected to generate intense soft X rays or warm X rays.The machine is 3.2 m in height and 22 m in outer diameter,including support systems such as a high-voltage charge supply,magnetic core reset system,trigger system,and support platform for inner stalk installation and maintenance.A total of 1440 individual±100-kV multi-gap spark switches and 2880 individual 100-kV capacitors are employed in the accelerator.A total of 12 fiberoptic laser-controlled trigger generators combining photoconductive and traditional gas spark switch technologies are used to realize the synchronous discharge of the more than 1000 gas switches.At an LTD charge voltage of±85 kV,the accelerator stores an initial energy of about 300 kJ and is expected to deliver a current of 3–5 MA into various loads.To date,the LTD facility has shot into a thick-walled aluminum liner load and a reflex triode load.With a thick-walled aluminum liner of inductance 1.81 nH,a current with peak up to 4.1 MA and rise time(10%–90%)of about 60 ns has been achieved.The current transport efficiency from the insulator stack to the liner load approaches 100%during peak times.The LTD accelerator has been used to drive reflex triode loads generating warm X rays with high energy fluence and large radiation area.It has been demonstrated that this LTD is a promising and high-efficiency prime pulsed power source suitable for use in constructing the next generation of large-scale accelerators with currents of tens of megaamperes.展开更多
Excellent magnetostrictive properties and processability are the two most important key factors for the practical application of magnetostrictive materials and research directions of continuous concern.In this study,w...Excellent magnetostrictive properties and processability are the two most important key factors for the practical application of magnetostrictive materials and research directions of continuous concern.In this study,we significantly improved the magnetostriction,ductility,and tensile strength of Fe_(83)Ga_(17)B_(x)(x=0,1,2,3,and 4)alloys by adjusting the small-radius boron(B)doping concentration.When x=3,the maximum magnetostriction value reached 193 ppm,approximately twice that of the undoped alloy(x=0),while the ultimate tensile strength and elongation increased by 147%and 238%,respectively,compared to Fe_(83)Ga_(17)alloys.Both first-principles calculations and experimental results indicate that B doping facilitates the alignment of FeGa crystal growth direction with the easy magnetization axis,thereby significantly improving the magnetostrictive properties of the alloy.Additionally,increasing B content progressively refines the grain size and promotes Fe_(2)B phase formation,thereby enhancing both strength and toughness.At x=3,the material exhibits the highest saturation magnetization and the lowest coercivity.Therefore,the results show that doping small-radius atoms in the interstitial sites can effectively enhance the magnetostrictive and mechanical properties of FeGa materials.This work offers a promising strategy for designing magnetostrictive materials with superior overall properties.展开更多
In-situ TiB_(2)/Al–Cu composite was processed by multidirectional forging(MDF)for six passes.The microstructure evolution of the forged workpiece was examined across various regions.The mechanical properties of the a...In-situ TiB_(2)/Al–Cu composite was processed by multidirectional forging(MDF)for six passes.The microstructure evolution of the forged workpiece was examined across various regions.The mechanical properties of the as-cast and MDFed composites were compared,and their strengthening mechanisms were analyzed.Results indicate that the grain refinement achieved through the MDF process is mainly due to the subdivision of the original grains through mechanical geometric fragmentation and the occurrence of dynamic recrystallization(DRX).DRX grains are formed through discontinuous DRX,continuous DRX,and recrystallization induced by particle-stimulated nucleation.A rise in accumulated equivalent strain(Σ?ε)results in finerα-Al grains and a more uniform distribution of TiB_(2)particles,which enhance the Vickers hardness of the composite.In addition,the tensile properties of the MDFed composite significantly improve compared with those of the as-cast composites,with ultimate tensile strength and yield strength increasing by 51.2%and 54%,respectively.This enhancement is primarily due to grain refinement strengthening and dislocation strengthening achieved by the MDF process.展开更多
Organic magnetic semiconductors have aroused much attention for spintronic applications. However, it remains challenging to achieve organic semiconductors with strong room-temperature ferromagnetism. Here, we report a...Organic magnetic semiconductors have aroused much attention for spintronic applications. However, it remains challenging to achieve organic semiconductors with strong room-temperature ferromagnetism. Here, we report a two-dimensional (2D) tetragonal organic-inorganic ferrimagnetic (FIM) semiconductor of Fe_(14)Se_(16)(peha)_(0.7) (peha = pentaethylenehexamine) with excellent thermal stability and a Curie temperature (T_(C)) higher than 519 K. Magnetic and Mössbauer measurements reveal a long-range magnetic ordering in single crystalline Fe_(14)Se_(16)(peha)0.7 nanosheets. The saturation magnetization and coercivity are 5.9 emu g^(−1) and 0.42 kOe at 5 K, which slightly reduces to 4.6 emu g^(−1) and ∼0 Oe at 300 K. A direct optical bandgap of 2.22 eV is obtained by tuning electronic structure of β-Fe3Se4 host layers through spacer layers consisting of Fe^(3+) and peha. Electrical and Seebeck coefficient data indicate that the n-type semiconductor follows the thermally-activated conduction mechanism (lnρ ∝ T^(−1)) in a range of 130–300 K with an activation energy (Ea) of 62.69 meV. Thermal conductivity is 2.5 W m^(−1) K^(−1) at 300 K, while the Wiedemann–Franz law is strongly violated according to electrical-thermal transport data due to weak incorporation of organic spacer layers and host layers. This study sets the stage for exploiting new room-temperature organic magnetic semiconductor systems for spintronic materials.展开更多
Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current method...Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.展开更多
The mutual coupling of structure and magnetism is crucial for Heusler alloys.In this paper,Ni_(50)Mn_(34)Sb_(16-x)Ga_(x)(0≤x≤16)alloys were prepared by arc melting.Based on the test results of structure and magnetis...The mutual coupling of structure and magnetism is crucial for Heusler alloys.In this paper,Ni_(50)Mn_(34)Sb_(16-x)Ga_(x)(0≤x≤16)alloys were prepared by arc melting.Based on the test results of structure and magnetism,the magnetic-structural phase diagram of Ni_(50)Mn_(34)Sb_(16-x)Ga_(x)(0≤x≤16)was drawn.The structure changes from cubic to monoclinic and finally to tetragonal as the x increases at room temperature.Its phase diagram shows a morphotropic phase boundary(MPB)starting from a tricritical triple point(around the Ni_(50)Mn_(34)Sb_(5)Ga_(11)alloy)of a cubic paramagnetic phase,ferromagnetic monoclinic,and antiferromagnetic tetragonal phases.And Ni_(50)Mn_(34)Sb_(5)Ga_(11)alloy has experienced five different phase states:paramagnetic austenite→ferromagnetic austenite→antiferromagnetic martensite→ferromagnetic martensite→spin glass as the temperature decreased.Further study of the alloys’magnetostrictive properties near the MPB showed that as x increases,a negative strain initially appears,followed by a W-type that crosses negative and positive strains,and then a positive strain.This is caused by the inconsistency in the speed and degree of magnetic domain walls response with monoclinic and tetragonal coexisting structures.This indicates that coupling between structure and magnetism is critical to the properties of materials.This work provides valuable insights into the magnetostrictive behavior and structural evolution of Heusler alloys,particularly in the context of MPB systems,and offers guidance for the design and optimization of material properties through controlled magnetic-structural interactions.Kindly check and confirm the edit made in the title.The edit made in the title has been confirmed to be accurate.展开更多
Genotyping by Target Sequencing(GBTS)technology,known for its flexibility,high efficiency,high throughput,and low cost,has been increasingly employed in molecular breeding.However,there is still limited study on the d...Genotyping by Target Sequencing(GBTS)technology,known for its flexibility,high efficiency,high throughput,and low cost,has been increasingly employed in molecular breeding.However,there is still limited study on the design and development of high-throughput genotyping tools in watermelon.In this study,we identified 112000 high quality SNPs by analyzing the resequencing data of 43 cultivated watermelon accessions.11921 and 6094 SNPs were selected for developing two sets of watermelon liquid-phase chips with different marker densities,named Watermelon 10K and 5K,respectively.Furthermore,the SNPs and Indels of most mapped gene/QTLs for many agronomic important traits in watermelon were also integrated into the two chips for foreground selection.These chips have been tested using GBTS technology in various applications in watermelon.The genotyping of 76 accessions by Watermelon 5K liquid-phase chip showed an average detection rate of 99.28%and 81.78%for cultivated and wild watermelon accessions,respectively.This provided enough markers information for GWAS and two significant QTLs,ssc1.1 and ssc1.2,associated with soluble sugar content were detected.Furthermore,BSA-seq analysis for non-lobed leaf and dwarf traits were validated by liquid-phase chips,and the candidate region was consistent with our previous studies.Additionally,we precisely introduced the Cldw1 and Clbl genes into an elite inbred line WT2 using Watermelon 5K for assisted selection,resulting in the development of three new germplasm with good plant architecture.As a high-throughput genotyping liquid-phase SNP array,the Watermelon 10K and 5K chips will greatly facilitate functional studies and molecular breeding in watermelon.展开更多
The color and pattern of watermelon rind are crucial external traits that directly affect consumer preferences.Watermelons with stripes having a stronger color than the background rind are ideal for studying stripe pa...The color and pattern of watermelon rind are crucial external traits that directly affect consumer preferences.Watermelons with stripes having a stronger color than the background rind are ideal for studying stripe patterns in plants,while there is still limited knowledge about the genetic mechanisms underlying stripe coloration due to the lack of germplasm resources.In this study,we focused on a watermelon germplasm with colorless stripes,and genetic analysis revealed that the trait is controlled by a single recessive gene.The gene Clsc(Citrullus lanatus stripe coloration),which is responsible for the colorless stripe,was localized into a 147.6 kb region on Chr9 by linkage analysis in a large F2 mapping population.Further analysis revealed that the Cla97C09G175170 gene encodes the APRR2 transcription factor,plays a crucial role in determining the watermelon colorless stripe phenotype and was deduced to be related to chlorophyll synthesis and chloroplast development.Physiological experiments indicated that Cla97C09G175170 may significantly influence chloroplast development and chlorophyll synthesis in watermelon.The results of this study provide a better understanding of the molecular mechanism of stripe coloration in watermelon and can be useful in the development of marker-assisted selection(MAS)for new watermelon cultivars.展开更多
A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and su...A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and surface morphology of the cladded layer were analyzed using energy dispersive X-ray spectroscopy （EDX）, scanning electron microscope （SEM）, and X-ray diffractometry （XRD）. The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. The microstructure of the coating was mainly composed of γ-Ni dendrites, a small amount of CrB, Ni3B, M23C6 and dispersed TiC particles. Much more and larger TiC particles formed in the overlapping zone, which led to a slightly higher microhardness of this zone. The maximum microhardness of the coating was about HV0.21200. The effects of the laser processing parameters on the microstructures and properties of coating were also investigated.展开更多
Tylorrhynchus heterochaetus is a widespread benthic polychaete worm found in coastal brackish waters of the west Pacific.It has high ecological and economic value as a biomarker of water quality and as a high-quality ...Tylorrhynchus heterochaetus is a widespread benthic polychaete worm found in coastal brackish waters of the west Pacific.It has high ecological and economic value as a biomarker of water quality and as a high-quality feed in aquaculture and fisheries and is considered a delicacy in some areas of Asia.However,it has experienced a marked reduction in recent years due to overexploitation as well as changes in the environment and climate.Here,to comprehensively understand its genetic background and thus provide insights for better conservation and utilization of this species,we assessed the genetic variability and demographic history of T.heterochaetus individuals sampled from eight locations along the coasts of southeast China and north Vietnam based on mitochondrial cytochrome c oxidase I(COI)sequences.We observed high haplotype diversity(Hd),with an average of 0.926,but relatively low nucleotide diversity(π),with a mean of 0.032 across all samples.A total of 94 polymorphic sites and 85 haplotypes were identified among 320 individuals.The pairwise genetic distances among haplotypes ranged from 0.001 to 0.067,with the high intraspecific divergence possibly reflecting geographic isolation and gene pool fragmentation.Significant genetic structures were revealed among the studied locations;specifically,the eight locations could be treated as six genetically different populations based on pairwiseΦST results(0.026–0.951,P<0.01).A significant pattern of isolation-by-distance was detected between the genetic and geographic distances(r=0.873,P=0.001).Three geographic lineages were defined based on phylogenetic tree and network analyses of COI haplotypes.AMOVA results indicated that genetic variations mainly occurred among the three lineages(89.96%).Tests of neutrality and mismatch distribution suggested that T.heterochaetus underwent recent population expansion.These results provide the first report on the genetic status of T.heterochaetus and will be valuable for the management of genetic resources and better understanding of the ecology and evolution in this species.展开更多
The cucumber(Cucumis sativus L.)is an important vegetable crop worldwide,and fruit trichomes or spines are an important trait for external fruit quality.The mechanisms underlying spine formation are not well understoo...The cucumber(Cucumis sativus L.)is an important vegetable crop worldwide,and fruit trichomes or spines are an important trait for external fruit quality.The mechanisms underlying spine formation are not well understood,but the plant-specific NAC family of transcription factors may play important roles in fruit spine initiation and development.In this study,we conducted a genome-wide survey and identified 91 NAC gene homologs in the cucumber genome.Clustering analysis classified these genes into six subfamilies;each contained a varying number of NAC family members with a similar intron–exon structure and conserved motifs.Quantitative real-time PCR analysis revealed tissue-specific expression patterns of these genes,including 10 and 12 that exhibited preferential expression in the stem and fruit,respectively.Thirteen of the 91 NAC genes showed higher expression in the wild-type plant than in its near-isogenic trichome mutant,suggesting their important roles in fruit spine development.Exogenous application of four plant hormones promoted spine formation and increased spine density on the cucumber fruits;several NAC genes showed differential expression over time in response to phytohormone treatments on cucumber fruit,implying their essential roles in fruit-trichome development.Among the NAC genes identified,12 were found to be targets of 13 known cucumber micro-RNAs.Collectively,these findings provide a useful resource for further analysis of the interactions between NAC genes and genes underlying trichome organogenesis and development during fruit spine development in cucumber.展开更多
Objective:To observe the impacts of electroacupuncture(EA)at auricular concha on gastrointestinal motility in the rats with type 2 diabetes(T2D).Methods:A total of 30 SD male rats were collected.8 rats of them were in...Objective:To observe the impacts of electroacupuncture(EA)at auricular concha on gastrointestinal motility in the rats with type 2 diabetes(T2D).Methods:A total of 30 SD male rats were collected.8 rats of them were in a control group and the rest22 rats were prepared as the model of T2D by intraperitoneal injection with streptozotocin(STZ)and high-fat forage.Blood glucose≥16.7 mmol/L for 3 times was considered as modeling success in rats,thus the rats were collected in a T2D group(n=16).These 16 T2D rats were divided into a model group(n=8)and an intradermal auricular electroacupuncture stimulation(iaES)group(n=8)according to random number table.In the iaES group,intervention with EA was applied at auricular concha unilaterally each time,once daily,on both sides alternatively,5-day treatment as 1 course,at the interval of 2 days between courses,totally for 4 weeks.No any intervention was given in the model group and the control group.At the end of 4 weeks of intervention,the gastric emptying and intestinal propulsion were determined,ELISA method was adopted to determine gastrin(GAS)and motilin(MTL),and random blood glucose value and food intake were recorded in the iaES group,the model group and the control group successively.Results:After modeling,as compared with the control group,the food intake and random blood glucose were increased significantly(both P<0.001)and body weight was reduced obviously(P<0.01)in the T2D group.After intervention for 4 weeks,compared with the model group,the food intake and gastric content weight were obviously reduced(both P<0.05),the serum GAS content,gastric emptying and intestinal transit rate,as well as random blood glucose reduction were all higher(all P<0.05)in the rats of the iaES group,but the difference was not significant in MTL between the iaES groups and the model group(P>0.05).Conclusion:Electroacupuncture at auricular concha improves gastrointestinal motility in T2D model rats.展开更多
基金supported by the Postgraduate Innovation Program of Chongqing University of Science and Technology(Grant No.YKJCX2420605)Research Foundation of Chongqing University of Science and Technology(Grant No.ckrc20241225)+1 种基金Opening Projects of State Key Laboratory of Solid Waste Reuse for Building Materials(Grant No.SWR-2021-005)Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202401510)。
文摘Foam concrete is widely used in engineering due to its lightweight and high porosity.Its compressive strength,a key performance indicator,is influenced by multiple factors,showing nonlinear variation.As compressive strength tests for foam concrete take a long time,a fast and accurate prediction method is needed.In recent years,machine learning has become a powerful tool for predicting the compressive strength of cement-based materials.However,existing studies often use a limited number of input parameters,and the prediction accuracy of machine learning models under the influence of multiple parameters and nonlinearity remains unclear.This study selects foam concrete density,water-to-cement ratio(W/C),supplementary cementitious material replacement rate(SCM),fine aggregate to binder ratio(FA/Binder),superplasticizer content(SP),and age of the concrete(Age)as input parameters,with compressive strength as the output.Five different machine learning models were compared,and sensitivity analysis,based on Shapley Additive Explanations(SHAP),was used to assess the contribution of each input parameter.The results show that Gaussian Process Regression(GPR)outperforms the other models,with R2,RMSE,MAE,and MAPE values of 0.95,1.6,0.81,and 0.2,respectively.It is because GPR,optimized through Bayesian methods,better fits complex nonlinear relationships,especially considering a large number of input parameters.Sensitivity analysis indicates that the influence of input parameters on compressive strength decreases in the following order:foam concrete density,W/C,Age,FA/Binder,SP,and SCM.
基金Project supported by the ESA-CMSA/CSU Space Science and Utilization Collaboration Program。
文摘An abnormally high peak friction angle of Ottawa sand was observed in(National Aeronautics and Space Administration) NASA–(Mechanics of Granular Materials) MGM tests in microgravity conditions on the space shuttle. Previous investigations have been unsuccessful in providing a constitutive insight into this behavior of granular materials under extremely low effective stress conditions. Here, a recently proposed unified constitutive model for transient rheological behavior of sand and other granular materials is adopted for the analytical assessment of high peak friction angles. For the first time, this long-eluded behavior of sand is attributed to a hidden rheological transition mechanism, that is not only rate-sensitive, but also pressure-sensitive. The NASA–MGM microgravity conditions show that shear-tests of sand can be performed under abnormally low confining stress conditions. The pressure-sensitive behavior of granular shearing that is previously ignored is studied based on the μ(I) rheology and its variations. Comparisons between the model and the NASA microgravity tests demonstrate a high degree of agreement. The research is highly valid for pressure-sensitive and rate-dependent problems that occur during earthquakes, landslides, and space exploration.
基金supported by the National Key R&D Program of China(No.2022YFE0109500)the National Natural Science Foundation of China(Nos.52071255,52301250,52171190 and 12304027)+2 种基金the Key R&D Project of Shaanxi Province(No.2022GXLH-01-07)the Fundamental Research Funds for the Central Universities(China)the World-Class Universities(Disciplines)and the Characteristic Development Guidance Funds for the Central Universities.
文摘With the rapid development of artificial intelligence,magnetocaloric materials as well as other materials are being developed with increased efficiency and enhanced performance.However,most studies do not take phase transitions into account,and as a result,the predictions are usually not accurate enough.In this context,we have established an explicable relationship between alloy compositions and phase transition by feature imputation.A facile machine learning is proposed to screen candidate NiMn-based Heusler alloys with desired magnetic entropy change and magnetic transition temperature with a high accuracy R^(2)≈0.98.As expected,the measured properties of prepared NiMn-based alloys,including phase transition type,magnetic entropy changes and transition temperature,are all in good agreement with the ML predictions.As well as being the first to demonstrate an explicable relationship between alloy compositions,phase transitions and magnetocaloric properties,our proposed ML model is highly predictive and interpretable,which can provide a strong theoretical foundation for identifying high-performance magnetocaloric materials in the future.
基金supported by the National Natural Science Foundation of China(Grant Nos.12027811 and 51790524).
文摘We have designed,assembled,and tested a 4-MA,60-ns fast linear transformer driver(LTD),which is the first operating generator featuring multiple LTD modules connected in parallel.The LTD-based accelerator comprises six modules in parallel,each of which has ten-stage cavities stacked in series.The six LTD modules are connected to a water tank of diameter 6 m via a 3-m-long impedance-matched deionized waterinsulated coaxial transmission line.In the water tank,the electrical pulses are transmitted down by six horizontal tri-plate transmission lines.A 2.1-m-diameter two-level vacuum insulator stack is utilized to separate the deionized water region from the vacuum region.In the vacuum,the currents are further transported downstream by a two-level magnetically insulated transmission-line and then converged through four post-hole convolutes.Plasma radiation loads or bremsstrahlung electron beam diodes serve as loads that are expected to generate intense soft X rays or warm X rays.The machine is 3.2 m in height and 22 m in outer diameter,including support systems such as a high-voltage charge supply,magnetic core reset system,trigger system,and support platform for inner stalk installation and maintenance.A total of 1440 individual±100-kV multi-gap spark switches and 2880 individual 100-kV capacitors are employed in the accelerator.A total of 12 fiberoptic laser-controlled trigger generators combining photoconductive and traditional gas spark switch technologies are used to realize the synchronous discharge of the more than 1000 gas switches.At an LTD charge voltage of±85 kV,the accelerator stores an initial energy of about 300 kJ and is expected to deliver a current of 3–5 MA into various loads.To date,the LTD facility has shot into a thick-walled aluminum liner load and a reflex triode load.With a thick-walled aluminum liner of inductance 1.81 nH,a current with peak up to 4.1 MA and rise time(10%–90%)of about 60 ns has been achieved.The current transport efficiency from the insulator stack to the liner load approaches 100%during peak times.The LTD accelerator has been used to drive reflex triode loads generating warm X rays with high energy fluence and large radiation area.It has been demonstrated that this LTD is a promising and high-efficiency prime pulsed power source suitable for use in constructing the next generation of large-scale accelerators with currents of tens of megaamperes.
基金financially supported by Shaanxi Provincial Key Laboratory Open Project(No.2022ZY2JCY1-01-05)the National Key Research and Development Program of China(No.2021YFB3501401)+3 种基金the National Natural Science Foundation of China(Nos.52171190 and 52301250)the Key Scientific and Technological Innovation Team of Shaanxi Province(No.2020TD001)the Innovation Capability Support Program of Shaanxi(Nos.2018PT-28 and 2017KTPT-04)the support from the High Performance Computing Center at Xi'an Jiaotong University
文摘Excellent magnetostrictive properties and processability are the two most important key factors for the practical application of magnetostrictive materials and research directions of continuous concern.In this study,we significantly improved the magnetostriction,ductility,and tensile strength of Fe_(83)Ga_(17)B_(x)(x=0,1,2,3,and 4)alloys by adjusting the small-radius boron(B)doping concentration.When x=3,the maximum magnetostriction value reached 193 ppm,approximately twice that of the undoped alloy(x=0),while the ultimate tensile strength and elongation increased by 147%and 238%,respectively,compared to Fe_(83)Ga_(17)alloys.Both first-principles calculations and experimental results indicate that B doping facilitates the alignment of FeGa crystal growth direction with the easy magnetization axis,thereby significantly improving the magnetostrictive properties of the alloy.Additionally,increasing B content progressively refines the grain size and promotes Fe_(2)B phase formation,thereby enhancing both strength and toughness.At x=3,the material exhibits the highest saturation magnetization and the lowest coercivity.Therefore,the results show that doping small-radius atoms in the interstitial sites can effectively enhance the magnetostrictive and mechanical properties of FeGa materials.This work offers a promising strategy for designing magnetostrictive materials with superior overall properties.
基金supported by the Key Program for International Cooperation of the Ministry of Science and Technology,China(No.ZCGX2022001L)。
文摘In-situ TiB_(2)/Al–Cu composite was processed by multidirectional forging(MDF)for six passes.The microstructure evolution of the forged workpiece was examined across various regions.The mechanical properties of the as-cast and MDFed composites were compared,and their strengthening mechanisms were analyzed.Results indicate that the grain refinement achieved through the MDF process is mainly due to the subdivision of the original grains through mechanical geometric fragmentation and the occurrence of dynamic recrystallization(DRX).DRX grains are formed through discontinuous DRX,continuous DRX,and recrystallization induced by particle-stimulated nucleation.A rise in accumulated equivalent strain(Σ?ε)results in finerα-Al grains and a more uniform distribution of TiB_(2)particles,which enhance the Vickers hardness of the composite.In addition,the tensile properties of the MDFed composite significantly improve compared with those of the as-cast composites,with ultimate tensile strength and yield strength increasing by 51.2%and 54%,respectively.This enhancement is primarily due to grain refinement strengthening and dislocation strengthening achieved by the MDF process.
基金supported by the National Natural Science Foundation of China(Nos.52371203,51971221 and 52031014).
文摘Organic magnetic semiconductors have aroused much attention for spintronic applications. However, it remains challenging to achieve organic semiconductors with strong room-temperature ferromagnetism. Here, we report a two-dimensional (2D) tetragonal organic-inorganic ferrimagnetic (FIM) semiconductor of Fe_(14)Se_(16)(peha)_(0.7) (peha = pentaethylenehexamine) with excellent thermal stability and a Curie temperature (T_(C)) higher than 519 K. Magnetic and Mössbauer measurements reveal a long-range magnetic ordering in single crystalline Fe_(14)Se_(16)(peha)0.7 nanosheets. The saturation magnetization and coercivity are 5.9 emu g^(−1) and 0.42 kOe at 5 K, which slightly reduces to 4.6 emu g^(−1) and ∼0 Oe at 300 K. A direct optical bandgap of 2.22 eV is obtained by tuning electronic structure of β-Fe3Se4 host layers through spacer layers consisting of Fe^(3+) and peha. Electrical and Seebeck coefficient data indicate that the n-type semiconductor follows the thermally-activated conduction mechanism (lnρ ∝ T^(−1)) in a range of 130–300 K with an activation energy (Ea) of 62.69 meV. Thermal conductivity is 2.5 W m^(−1) K^(−1) at 300 K, while the Wiedemann–Franz law is strongly violated according to electrical-thermal transport data due to weak incorporation of organic spacer layers and host layers. This study sets the stage for exploiting new room-temperature organic magnetic semiconductor systems for spintronic materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52271033 and 52071179)the Key program of National Natural Science Foundation of China(No.51931003)+2 种基金Natural Science Foundation of Jiangsu Province,China(No.BK20221493)Jiangsu Province Leading Edge Technology Basic Research Major Project(No.BK20222014)Foundation of“Qinglan Project”for Colleges and Universities in Jiangsu Province.
文摘Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.
基金supported by the National Key Research and Development Program of China(Nos.2022YFE0109500 and 2021YFB3501401)the National Natural Science Foundation of China(Nos.52171190 and 52301250).
文摘The mutual coupling of structure and magnetism is crucial for Heusler alloys.In this paper,Ni_(50)Mn_(34)Sb_(16-x)Ga_(x)(0≤x≤16)alloys were prepared by arc melting.Based on the test results of structure and magnetism,the magnetic-structural phase diagram of Ni_(50)Mn_(34)Sb_(16-x)Ga_(x)(0≤x≤16)was drawn.The structure changes from cubic to monoclinic and finally to tetragonal as the x increases at room temperature.Its phase diagram shows a morphotropic phase boundary(MPB)starting from a tricritical triple point(around the Ni_(50)Mn_(34)Sb_(5)Ga_(11)alloy)of a cubic paramagnetic phase,ferromagnetic monoclinic,and antiferromagnetic tetragonal phases.And Ni_(50)Mn_(34)Sb_(5)Ga_(11)alloy has experienced five different phase states:paramagnetic austenite→ferromagnetic austenite→antiferromagnetic martensite→ferromagnetic martensite→spin glass as the temperature decreased.Further study of the alloys’magnetostrictive properties near the MPB showed that as x increases,a negative strain initially appears,followed by a W-type that crosses negative and positive strains,and then a positive strain.This is caused by the inconsistency in the speed and degree of magnetic domain walls response with monoclinic and tetragonal coexisting structures.This indicates that coupling between structure and magnetism is critical to the properties of materials.This work provides valuable insights into the magnetostrictive behavior and structural evolution of Heusler alloys,particularly in the context of MPB systems,and offers guidance for the design and optimization of material properties through controlled magnetic-structural interactions.Kindly check and confirm the edit made in the title.The edit made in the title has been confirmed to be accurate.
基金supported by the National Natural Science Foundation of China(Grant Nos.32172602,32472739)the Major Science and Technology Project of Henan Province(Grant No.221100110400)+3 种基金the Funding of Joint Research on Agricultural Varietie Improvement of Henan Province(Grant No.2022010503)the Natural Science Foundation of Henan(Grant No.242300421030)the Key Scientifc and Technological Project of Henan Province(Grant Nos.242102111124,242102111115)the Key Research and Development Program of Xinjiang Uygur autonomous region(2023B02017-2).
文摘Genotyping by Target Sequencing(GBTS)technology,known for its flexibility,high efficiency,high throughput,and low cost,has been increasingly employed in molecular breeding.However,there is still limited study on the design and development of high-throughput genotyping tools in watermelon.In this study,we identified 112000 high quality SNPs by analyzing the resequencing data of 43 cultivated watermelon accessions.11921 and 6094 SNPs were selected for developing two sets of watermelon liquid-phase chips with different marker densities,named Watermelon 10K and 5K,respectively.Furthermore,the SNPs and Indels of most mapped gene/QTLs for many agronomic important traits in watermelon were also integrated into the two chips for foreground selection.These chips have been tested using GBTS technology in various applications in watermelon.The genotyping of 76 accessions by Watermelon 5K liquid-phase chip showed an average detection rate of 99.28%and 81.78%for cultivated and wild watermelon accessions,respectively.This provided enough markers information for GWAS and two significant QTLs,ssc1.1 and ssc1.2,associated with soluble sugar content were detected.Furthermore,BSA-seq analysis for non-lobed leaf and dwarf traits were validated by liquid-phase chips,and the candidate region was consistent with our previous studies.Additionally,we precisely introduced the Cldw1 and Clbl genes into an elite inbred line WT2 using Watermelon 5K for assisted selection,resulting in the development of three new germplasm with good plant architecture.As a high-throughput genotyping liquid-phase SNP array,the Watermelon 10K and 5K chips will greatly facilitate functional studies and molecular breeding in watermelon.
基金supported by grants from theKey Scientific and Technological Project of Henan Province,China(222102110124)the Joint Fund of Science and Technology Research and Development Plan,Henan Province,China(222103810009)+4 种基金the National Natural Science Foundation of China(32172574,3217180560)the Funding of Joint Research on Agricultural Varieties Improvement of Henan Province,China(2022010503)the Major Science and Technology Project of Henan Province,China(221100110400)the Natural Science Foundation of Henan,China(222300420050)the Science and Technology Innovation Talent Support Program of Henan Province,China(23HASTIT034).
文摘The color and pattern of watermelon rind are crucial external traits that directly affect consumer preferences.Watermelons with stripes having a stronger color than the background rind are ideal for studying stripe patterns in plants,while there is still limited knowledge about the genetic mechanisms underlying stripe coloration due to the lack of germplasm resources.In this study,we focused on a watermelon germplasm with colorless stripes,and genetic analysis revealed that the trait is controlled by a single recessive gene.The gene Clsc(Citrullus lanatus stripe coloration),which is responsible for the colorless stripe,was localized into a 147.6 kb region on Chr9 by linkage analysis in a large F2 mapping population.Further analysis revealed that the Cla97C09G175170 gene encodes the APRR2 transcription factor,plays a crucial role in determining the watermelon colorless stripe phenotype and was deduced to be related to chlorophyll synthesis and chloroplast development.Physiological experiments indicated that Cla97C09G175170 may significantly influence chloroplast development and chlorophyll synthesis in watermelon.The results of this study provide a better understanding of the molecular mechanism of stripe coloration in watermelon and can be useful in the development of marker-assisted selection(MAS)for new watermelon cultivars.
基金The authors are grateful for the financial support provided by the National Natural Science Foundation of China(Nos.51901101,11802131,52071180)the Projects in Science and Technique Plans of Ningbo City,China(No.2019B10083)+1 种基金the Natural Science Foundation of Jiangsu Province,China(Nos.BK20191292,BK20201308)the Fundamental Research Funds for the Central Universities of China(No.30919011256).
基金This research was supported by the Natural Science Foundation of Inner Mongolia （No. 200508010704）the Science Foundation of Inner Mongolia University of Technology （No. ZD200521） the Postdoctoral Science Foundation of China.
文摘A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and surface morphology of the cladded layer were analyzed using energy dispersive X-ray spectroscopy （EDX）, scanning electron microscope （SEM）, and X-ray diffractometry （XRD）. The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. The microstructure of the coating was mainly composed of γ-Ni dendrites, a small amount of CrB, Ni3B, M23C6 and dispersed TiC particles. Much more and larger TiC particles formed in the overlapping zone, which led to a slightly higher microhardness of this zone. The maximum microhardness of the coating was about HV0.21200. The effects of the laser processing parameters on the microstructures and properties of coating were also investigated.
基金supported by the IndustryAcademic Research Cooperation Program of Academician Workstation of Guangdong Province(2013B090400017)Natural Science Foundation of Guangdong Province(2016A030307036)Yangfan Innovative&Entrepreneurial Research Team Project for Guangdong Province(201312H10)
文摘Tylorrhynchus heterochaetus is a widespread benthic polychaete worm found in coastal brackish waters of the west Pacific.It has high ecological and economic value as a biomarker of water quality and as a high-quality feed in aquaculture and fisheries and is considered a delicacy in some areas of Asia.However,it has experienced a marked reduction in recent years due to overexploitation as well as changes in the environment and climate.Here,to comprehensively understand its genetic background and thus provide insights for better conservation and utilization of this species,we assessed the genetic variability and demographic history of T.heterochaetus individuals sampled from eight locations along the coasts of southeast China and north Vietnam based on mitochondrial cytochrome c oxidase I(COI)sequences.We observed high haplotype diversity(Hd),with an average of 0.926,but relatively low nucleotide diversity(π),with a mean of 0.032 across all samples.A total of 94 polymorphic sites and 85 haplotypes were identified among 320 individuals.The pairwise genetic distances among haplotypes ranged from 0.001 to 0.067,with the high intraspecific divergence possibly reflecting geographic isolation and gene pool fragmentation.Significant genetic structures were revealed among the studied locations;specifically,the eight locations could be treated as six genetically different populations based on pairwiseΦST results(0.026–0.951,P<0.01).A significant pattern of isolation-by-distance was detected between the genetic and geographic distances(r=0.873,P=0.001).Three geographic lineages were defined based on phylogenetic tree and network analyses of COI haplotypes.AMOVA results indicated that genetic variations mainly occurred among the three lineages(89.96%).Tests of neutrality and mismatch distribution suggested that T.heterochaetus underwent recent population expansion.These results provide the first report on the genetic status of T.heterochaetus and will be valuable for the management of genetic resources and better understanding of the ecology and evolution in this species.
基金This work was supported by the National Natural Science Foundation of China(31672159)the National Key Research and Development Program of China(2016YFD0101705)+1 种基金the Project of Beijing Agricultural Innovation Consortium(BAIC01-2017)to HZRthe Beijing Municipal Natural Science Foundation(6184043)to XWL.
文摘The cucumber(Cucumis sativus L.)is an important vegetable crop worldwide,and fruit trichomes or spines are an important trait for external fruit quality.The mechanisms underlying spine formation are not well understood,but the plant-specific NAC family of transcription factors may play important roles in fruit spine initiation and development.In this study,we conducted a genome-wide survey and identified 91 NAC gene homologs in the cucumber genome.Clustering analysis classified these genes into six subfamilies;each contained a varying number of NAC family members with a similar intron–exon structure and conserved motifs.Quantitative real-time PCR analysis revealed tissue-specific expression patterns of these genes,including 10 and 12 that exhibited preferential expression in the stem and fruit,respectively.Thirteen of the 91 NAC genes showed higher expression in the wild-type plant than in its near-isogenic trichome mutant,suggesting their important roles in fruit spine development.Exogenous application of four plant hormones promoted spine formation and increased spine density on the cucumber fruits;several NAC genes showed differential expression over time in response to phytohormone treatments on cucumber fruit,implying their essential roles in fruit-trichome development.Among the NAC genes identified,12 were found to be targets of 13 known cucumber micro-RNAs.Collectively,these findings provide a useful resource for further analysis of the interactions between NAC genes and genes underlying trichome organogenesis and development during fruit spine development in cucumber.
基金Supported by Tradition Chinese Medicine Science Technology Project of Jiangsu Province:YB201808Postgraduate Practice Innovation Program of Jiangsu Province:KYCX20_1544。
文摘Objective:To observe the impacts of electroacupuncture(EA)at auricular concha on gastrointestinal motility in the rats with type 2 diabetes(T2D).Methods:A total of 30 SD male rats were collected.8 rats of them were in a control group and the rest22 rats were prepared as the model of T2D by intraperitoneal injection with streptozotocin(STZ)and high-fat forage.Blood glucose≥16.7 mmol/L for 3 times was considered as modeling success in rats,thus the rats were collected in a T2D group(n=16).These 16 T2D rats were divided into a model group(n=8)and an intradermal auricular electroacupuncture stimulation(iaES)group(n=8)according to random number table.In the iaES group,intervention with EA was applied at auricular concha unilaterally each time,once daily,on both sides alternatively,5-day treatment as 1 course,at the interval of 2 days between courses,totally for 4 weeks.No any intervention was given in the model group and the control group.At the end of 4 weeks of intervention,the gastric emptying and intestinal propulsion were determined,ELISA method was adopted to determine gastrin(GAS)and motilin(MTL),and random blood glucose value and food intake were recorded in the iaES group,the model group and the control group successively.Results:After modeling,as compared with the control group,the food intake and random blood glucose were increased significantly(both P<0.001)and body weight was reduced obviously(P<0.01)in the T2D group.After intervention for 4 weeks,compared with the model group,the food intake and gastric content weight were obviously reduced(both P<0.05),the serum GAS content,gastric emptying and intestinal transit rate,as well as random blood glucose reduction were all higher(all P<0.05)in the rats of the iaES group,but the difference was not significant in MTL between the iaES groups and the model group(P>0.05).Conclusion:Electroacupuncture at auricular concha improves gastrointestinal motility in T2D model rats.
