To investigate the evolution of grain orientation and slip modes in magnesium alloys with multiple texture components,an AZ31 gradient-structured magnesium alloy sheet was fabricated using hard plate rolling(HPR).The ...To investigate the evolution of grain orientation and slip modes in magnesium alloys with multiple texture components,an AZ31 gradient-structured magnesium alloy sheet was fabricated using hard plate rolling(HPR).The changes in texture and slip modes under different reductions were examined.The results demonstrate that the AZ31 magnesium alloy sheets display a self-epitaxial gradient structure,with the best mechanical properties observed at rolling temperature of 673 K and reduction of 50%.Significant changes in texture type and strength are observed along the normal direction(ND)of the sheet.The coarse-grain region exhibits a bimodal texture aligned with the rolling direction.These texture variations enhance the stress distribution at the fine grain-coarse grain interface,influencing the grain orientation and the activation of different slip modes,thus improving the mechanical properties of gradient-structured magnesium alloy sheets.This approach offers a new strategy for the fabrication of high-performance magnesium alloy sheets.展开更多
Acetolactate synthase(ALS)-targeting herbicides are among the most widely used weed-control chemicals globally.Mutations in the ALS gene can confer herbicide resistance in crops,thereby allowing selective elimination ...Acetolactate synthase(ALS)-targeting herbicides are among the most widely used weed-control chemicals globally.Mutations in the ALS gene can confer herbicide resistance in crops,thereby allowing selective elimination of weeds without harming crops.Herbicide-resistant ALS alleles were initially discovered in weeds and subsequently developed through artificial mutagenesis techniques.With the advancement of CRISPR/Cas technologies,various genome-editing tools are now available to introduce these resistant alleles,as well as novel variants,into diverse crop species.Moreover,emerging methodologies,such as directed evolution,enable the generation and screening of large populations of random ALS mutants.Consequently,ALS has become one of the most extensively targeted genes in plant gene evolution.This paper provides a comprehensive overview of both conventional and recently developed strategies for ALS evolution,with particular emphasis on CRISPR/Cas-based genome editing and directed evolution.Future perspectives on technological application are also discussed.By advancing our understanding of herbicide-resistant ALS allele development for crop improvement,these methodologies may also pave the way for their application to the evolution of other agronomically important genes.展开更多
To elucidate the deformation mechanisms ofγ-TiAl,the nanoindentation experiments and crystal plasticity finite element(CPFE)simulation were employed to investigate the effects of crystal orientations and GBs on the m...To elucidate the deformation mechanisms ofγ-TiAl,the nanoindentation experiments and crystal plasticity finite element(CPFE)simulation were employed to investigate the effects of crystal orientations and GBs on the mechanical properties ofγ-TiAl alloys.A crystal plasticity constitutive model was developed,and load-displacement curves,hardness,and Young's modulus were obtained for both single grains and GBs inγ-TiAl alloys.Based on the aforementioned model,this study investigated the distribution patterns of surface morphology around the indentation sites of individual grain and GBs.It also analyzed the cumulative shear strain distribution,slip system activation,and the interaction between GBs and dislocation slip for various crystal orientations.The results indicate that the mechanical response and pileup behavior exhibit significant anisotropy due to the interplay among the indenter geometry,material slip systems,and cumulative shear strain distribution.Moreover,the interaction between GBs and dislocation slip substantially alters dislocation distribution,thereby influencing material flow and playing a critical role in the mechanical response and plastic deformation of the material.展开更多
A composite electrocatalyst,CoMoNiO-S/NF-110(NF is nickel foam),was synthesized through electrodeposition,followed by pyrolysis and then the vulcanization process.CoMoNiO-S/NF-110 exhibited a structure where Ni3S2 and...A composite electrocatalyst,CoMoNiO-S/NF-110(NF is nickel foam),was synthesized through electrodeposition,followed by pyrolysis and then the vulcanization process.CoMoNiO-S/NF-110 exhibited a structure where Ni3S2 and Mo2S3 nanoparticles were integrated at the edges of Co3O4 nanosheets,creating a rich,heterogeneous interface that enhances the synergistic effects of each component.In an alkaline electrolyte,the synthesized CoMoNiO-S/NF-110 exhibited superior electrocatalytic performance for oxygen evolution reaction(OER),achieving current densities of 100 and 200 mA·cm^(-2) with low overpotentials of 199.4 and 224.4 mV,respectively,outperforming RuO2 and several high-performance Mo and Ni-based catalysts.This excellent performance is attributed to the rich interface formed between the components and active sites exposed by the defect structure.展开更多
Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under diff...Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under different deposition rates and grain orientations.The evolution of grain morphology and grain orientation was also taken into consideration.Simulation results show that at lower deposition rates,the surface of the formed Ti film exhibits a distinct oriented texture structure.The surface roughness of the Ti film is positively correlated with the grain misorientation.Moreover,the surface roughness obtained from the simulation is in good agreement with the experiment results.展开更多
The poor electrical conductivity of metal-organic frameworks(MOFs)limits their electrocatalytic performance in the oxygen evolution reaction(OER).In this study,a Py@Co-MOF composite material based on pyrene(Py)molecul...The poor electrical conductivity of metal-organic frameworks(MOFs)limits their electrocatalytic performance in the oxygen evolution reaction(OER).In this study,a Py@Co-MOF composite material based on pyrene(Py)molecules and{[Co2(BINDI)(DMA)_(2)]·DMA}_(n)(Co-MOF,H4BINDI=N,N'-bis(5-isophthalic acid)naphthalenediimide,DMA=N,N-dimethylacetamide)was synthesized via a one-pot method,leveragingπ-πinteractions between pyrene and Co-MOF to modulate electrical conductivity.Results demonstrate that the Py@Co-MOF catalyst exhibited significantly enhanced OER performance compared to pure Co-MOF or pyrene-based electrodes,achieving an overpotential of 246 mV at a current density of 10 mA·cm^(-2) along with excellent stability.Density functional theory(DFT)calculations reveal that the formation of O*in the second step is the rate-determining step(RDS)during the OER process on Co-MOF,with an energy barrier of 0.85 eV due to the weak adsorption affinity of the OH*intermediate for Co sites.CCDC:2419276.展开更多
The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor ...The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.展开更多
While methodology for determining the mode of evolution in coding sequences has been well established,evaluation of adaptation events in emerging types of phenotype data needs further development.Here,we propose an an...While methodology for determining the mode of evolution in coding sequences has been well established,evaluation of adaptation events in emerging types of phenotype data needs further development.Here,we propose an analysis framework(expression variance decomposition,EVaDe)for comparative single-cell expression data based on phenotypic evolution theory.After decomposing the gene expression variance into separate components,we use two strategies to identify genes exhibiting large between-taxon expression divergence and small within-cell-type expression noise in certain cell types,attributing this pattern to putative adaptive evolution.In a dataset of primate prefrontal cortex,we find that such humanspecific key genes enrich with neurodevelopment-related functions,while most other genes exhibit neutral evolution patterns.Specific neuron types are found to harbor more of these key genes than other cell types,thus likely to have experienced more extensive adaptation.Reassuringly,at the molecular sequence level,the key genes are significantly associated with the rapidly evolving conserved non-coding elements.An additional case analysis comparing the naked mole-rat(NMR)with the mouse suggests that innateimmunity-related genes and cell types have undergone putative expression adaptation in NMR.Overall,the EVaDe framework may effectively probe adaptive evolution mode in single-cell expression data.展开更多
The augmented evolution equation is established under the framework of the Variation Evolving Method(VEM)that seeks optimal solutions by solving the transformed Initial-Value Problems(IVPs).To improve the numerical pe...The augmented evolution equation is established under the framework of the Variation Evolving Method(VEM)that seeks optimal solutions by solving the transformed Initial-Value Problems(IVPs).To improve the numerical performance,its compact form is developed herein.Through replacing the states and costates variation evolution with that of the controls,the dimension-reduced Evolution Partial Differential Equation(EPDE)only solves the control variables along the variation time to get the optimal solution,and the initial conditions for the definite solution may be arbitrary.With this equation,the scale of the resulting IVPs,obtained via the semi-discrete method,is significantly reduced and they may be solved with common Ordinary Differential Equation(ODE)integration methods conveniently.Meanwhile,the state and the costate dynamics share consistent stability in the numerical computation and this avoids the intrinsic numerical difficulty as in the indirect methods.Numerical examples are solved and it is shown that the compact form evolution equation outperforms the primary form in the precision,and the efficiency may be higher for the dense discretization.Actually,it is uncovered that the compact form of the augmented evolution equation is a continuous realization of the Newton type iteration mechanism.展开更多
Optical tweezers technology has the characteristics of noncontact manipulation in three dimensions and steerable separation in solutions,and could be applied to obtain a separated sperm with high quality for intracyto...Optical tweezers technology has the characteristics of noncontact manipulation in three dimensions and steerable separation in solutions,and could be applied to obtain a separated sperm with high quality for intracytoplasmic sperm injection(ICSI).However,the effects of optical tweezers on sperm motility are still unclear.To elucidate the effects on sperm motility for optical tweezers,we systematically investigated the correlation between motility parameters and the parameters of optical tweezers(wavelength,power,trapping duration,and trapping orientation).Under three systems of optical tweezers with different laser wavelengths(1064,850,and 785 nm),the nine motility parameters of free swimming were mainly affected by trapping orientation(vertical/horizontal)and trapping duration.When 850 nm laser and 1064 nm laser are used,vertical trapping significantly reduces sperm free-swimming capability with prolonged exposure time,whereas horizontal trapping exhibits relatively minor interference on sperm motility.Notably,the 785 nm laser does not induce statistically significant changes in key parameters of sperm motility under any experimental conditions(trapping orientation and duration).For the rolling frequency of trapped sperm,horizontal trapping for three wavelengths has a negligible effect compared with vertical trapping,especially for the 785 nm laser.In conclusion,horizontal trapping can preserve sperm motility under low power(below 140mW at 1064 nm,below 100mW at 850nm,below 60mW at 785 nm)and short duration(below 4 min).This trapping duration is suffcient for the separation procedure of single live sperm in ICSI.This study provides critical parameter optimization guidelines for the safe application of optical tweezers technology in reproductive medicine.展开更多
Objectives:Non-suicidal self-injury(NSSI)represents a prominent and escalating concern within mental health,associated with considerable psychological and physical dangers.Peer victimization is identified as a signifi...Objectives:Non-suicidal self-injury(NSSI)represents a prominent and escalating concern within mental health,associated with considerable psychological and physical dangers.Peer victimization is identified as a significant predictor of NSSI behavior.Although prior research has explored the association between peer victimization and NSSI,the mechanisms underlying this relationship remain insufficiently understood.Utilizing social information processing theory frameworks,the present study seeks to examine the sequential mediating roles of a cognitive factor,future orientation,and a behavioral factor,social withdrawal,in middle school students.Methods:A cross-sectional survey was administered in China,involving 528 participants(261 females and 267 males;Meanage=13.71,standard deviation[SD]=0.93).Participants completed self-report measures assessing peer victimization via the Delaware Bullying Victimization Scale-Student Version,NSSI via the Adolescents Self-Harm Scale,future orientation via the Adolescent Future Orientation Questionnaire,and social withdrawal via the Social Withdrawal Questionnaire.Results:Findings indicated a significant positive correlation between peer victimization and NSSI(r=0.30,p<0.01).Additionally,future orientation and social withdrawal functioned as serial mediators,with an indirect effect of 0.01(95%CI:[0.01,0.02]),representing 2.70%of the total effect(𝛽=0.37,95%CI:[0.25,0.47]).Conclusions:The findings endorse a theoretical framework in which negative future outlook and social withdrawal are sequentially linked within the relationship between peer victimization and NSSI.Although the serial indirect effect observed is modest,it delineates a distinct associative pattern that characterizes adolescents subjected to victimization.These results carry practical significance for school-based intervention programs,indicating that targeting future perspectives and social connections may enhance strategies for preventing NSSI.展开更多
Magnesium alloys usually exhibit poor ductility because of their limited slip systems at room temperature.To overcome this intrinsic limitation,heterostructure design has emerged as an effective strategy for enhancing...Magnesium alloys usually exhibit poor ductility because of their limited slip systems at room temperature.To overcome this intrinsic limitation,heterostructure design has emerged as an effective strategy for enhancing their mechanical performance,yet the development of orientation-based heterogeneous magnesium alloys remains relatively unexplored.In this work,by varying the triaxial cyclic compression(TCC)applied to an extruded Mg-2.9Y(wt.%)alloy,we obtained two materials that possessed comparable bimodal grain-size characteristics but showed notable differences in orientation heterogeneity.The material processed by TCC along three orthogonal directions for five complete cycles exhibited a predominantly hard orientation,with hard refined grains embedded within coarse grains of the same hard orientation.By applying an additional compression to plane A,the other material mainly comprising the soft orientation was obtained,with hard-oriented refined grains embedded in soft-oriented coarse grains.These materials exhibited quite different tensile properties and work hardening abilities.By combining microstructural characterization and crystal plasticity modeling,deformation micromechanism of the materials under tensile loading was explored.In the former,poor deformation coordination between the different domains led to strain localization in the refined grain region.However,the latter experienced a significant orientation transition due to tensile twinning.This promoted non-basalslip and improved deformation compatibility,resulting in the more persistent hetero-deformation induced hardening.These findings provide fundamental insights into the micromechanical behavior of heterostructured alloys and offer a new strategy for designing high-performance hexagonal close-packed materials by introducing heterogeneous orientation distributions.展开更多
Zinc oxide(ZnO)films,as representative piezoelectric semiconductors,have garnered considerable interest in ultrasonic testing.Current research challenges include maintaining the consistency of continuous c-axis orient...Zinc oxide(ZnO)films,as representative piezoelectric semiconductors,have garnered considerable interest in ultrasonic testing.Current research challenges include maintaining the consistency of continuous c-axis orientation and determining the fundamental link between the electrical structure and piezoelectric response.Accordingly,we have proposed ZnO films incorporated with an orientation-inducing layer(OIL),utilizing orientation induction and rapid deposition technology to regulate the growth structure of the ZnO films.Furthermore,the influence of the competitive mechanism between the film growth and lateral diffusion on the film's growth structure has been investigated.Piezoelectric force microscopy(PFM)analysis demonstrated the regulation and enhancement of ZnO piezoelectric polarization by the OIL.The enhancement mechanism of OIL on film performance was revealed via experimental examination of the film structure,morphology,crystallization orientation,oxygen vacancies,carrier concentration,band structure,and density of states based on density functional theory(DFT).Benefiting from the superior electromechanical response of the ZnO OIL sensor,characterized by fast response recovery times of 2.4 ms/7.7 ms and a sensitivity of 1.09 V/N,the device has successfully demonstrated practical applications in both motion pressure detection and bolt axial force measurement.These findings provide new insights into the ultrasonic detection for aerospace applications of ZnO OIL piezoelectric devices and demonstrate significant potential for health monitoring in connection systems.展开更多
This study presents a comprehensive phylogenetic analysis on Batrachospermaceae based on key taxonomic identifiers(rbcL,psaA,psbA,and COI-5P)from some genera.To systematically explore the phylogenetic relationships an...This study presents a comprehensive phylogenetic analysis on Batrachospermaceae based on key taxonomic identifiers(rbcL,psaA,psbA,and COI-5P)from some genera.To systematically explore the phylogenetic relationships and taxonomy within Batrachospermaceae,we integrated molecular and morphological data,and explored the phylogeny,character evolution,and ancestral geographical origin and provided a theoretical support for the classification and geographic origination of Batrachospermaceae.Our findings reveal distinct relationships within the phylogenetic tree.Notably,10 genera(Sirodotia,Batrachospermum,Tuomeya,Volatus,Lympha,Nothocladus,Torularia,Sheathia,Nocturama,and Petrohua)are closely associated in the rbcL phylogenetic tree.Additionally,four genera(Kumanoa,Hoefkenia,Notohesperus,and Virescentia)exhibit high support ratios,indicating their close interrelations.Other genera,including Paludicola,Visia,Acarposporophycos,Macrosporophycos,Visioidea,Balliopsis,and Psilosiphon,exhibit clustering traits.Furthermore,the multigene sequences provide a robust support for Montagnia that forms a monophyletic group.Ancestral reconstruction of morphological characters identifies nine primitive character states,including whorl,fascicle length,cortical cells,secondary fascicles,the shape of carpogonical branch,spermatangia,carposporophyte,carpogonium and trichogyne,with Visia likely representing ancestral traits in Batrachospermaceae.Furthermore,geographical origin maps suggest a potential common ancestral of Batrachospermaceae origin in the American continent.Additional to conventional analyses,including evolutionary and ancestral reconstruction investigations into key morphological characters,we attempt to reconstruct the biogeography within the Batrachospermaceae,thus contributing to a nuanced understanding of its origin.展开更多
Turbine blades,due to their intricate geometry,are exposed to multiaxial stresses during operation.Consequently,it is imperative to examine the anisotropy of their stress-rupture behavior across various testing scenar...Turbine blades,due to their intricate geometry,are exposed to multiaxial stresses during operation.Consequently,it is imperative to examine the anisotropy of their stress-rupture behavior across various testing scenarios,particularly under high-temperature conditions.Stress-rupture behavior of a Ni-based single crystal superalloy was investigated under a load varying from 100 MPa to 137 MPa at 1,100℃ for both[001]-and[111]-orientated specimens.Results demonstrate that the rupture behavior of[111]-orientated specimens exhibits obviously higher sensitive to applied stress compared to[001]-orientated specimens.This difference is primarily attributed to the orientation dependentγ'coarsening behavior and distinct dislocation interactions atγ/γ'interfaces.In[001]-oriented specimens,plate-likeγ/γ'rafts rapidly form alongside well-developed interfacial dislocation networks,where theγ/γ'misfit stress dominates the microstructural evolution.In contrast,the[111]-orientated specimens exhibit retained,coarsenedγ'precipitates embedded within theγmatrix,accompanied by poorly developed interfacial dislocation networks.展开更多
Developing catalysts with excellent stability while significantly reducing the overpotential of the oxygen evolution reaction(OER) is crucial for advancing overall water splitting(OWS) systems.In this study,we synthes...Developing catalysts with excellent stability while significantly reducing the overpotential of the oxygen evolution reaction(OER) is crucial for advancing overall water splitting(OWS) systems.In this study,we synthesized the electrode material Ce-NiCo-LDHs@SnO_(2)/NF through a two-step hydrothermal reaction,where Ce-doped NiCo-LDHs are grown on nickel foam modified by a SnO_(2) layer.Ce doping adjusts the internal electronic distribution of Ni Co-LDHs,while the introduction of the SnO_(2) layer enhances electron transfer capability.Together,these factors contribute to the reduction of the OER energy barrier and experimental evidence confirms that the reaction proceeds via the lattice oxygen evolution mechanism(LOM).Consequently,Ce-NiCo-LDHs@SnO_(2)/NF exhibits high level electrochemical performance in OER,requiring only 234 m V overpotential to achieve a current density of 10 m A/cm^(2),with a Tafel slope of just 27.39 m V/dec.When paired with Pt/C/NF,an external potential of only 1.54 V is needed to drive OWS to attain a current density amounting to 10 m A/cm^(2).Furthermore,the catalyst demonstrates stability for 100 h during the OWS stability test.This study underscores the feasibility of enhancing the OER performance through Ce doping and the introduction of a conductive SnO_(2) layer.展开更多
Developing efficient and durable electrocatalysts for acidic oxygen evolution reaction(OER)is pivotal for advancing proton exchange membrane water electrolysis(PEMWEs),yet balancing activity and stability remains a fo...Developing efficient and durable electrocatalysts for acidic oxygen evolution reaction(OER)is pivotal for advancing proton exchange membrane water electrolysis(PEMWEs),yet balancing activity and stability remains a formidable challenge.Herein,we propose a dual-engineering strategy to stabilize Ru-based catalysts by synergizing the oxygen vacancy site-synergized mechanism-lattice oxygen mechanism(OVSM-LOM)with Ru-N bond stabilization.The engineered RuO_(2)@NCC catalyst exhibits exceptional OER performance in 0.5 M H2SO4,achieving an ultralow overpotential of 215 mV at 10 mA cm^(-2) and prolonged stability for over 327 h.The catalyst delivers 300 h of continuous operation at 1 A cm^(-2),with a negligible degradation rate of only 0.067 mV h-1,further demonstrating its potential for practical application.Oxygen vacancies unlock the OVSM-LOM pathway,bypassing the sluggish adsorbate evolution mechanism(AEM)and accelerating reaction kinetics,while the Ru-N bonds suppress Ru dissolution by anchoring low-valent Ru centers.Quasi-in situ X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),and isotopic labeling experiments confirm the lattice oxygen participation with *O formation as the rate-determining step.The Ru-N bonds reinforce the structural integrity by stabilizing low-valent Ru centers and inhibiting overoxidation.Theoretical calculations further verify that the synergistic interaction between OVs and Ru-O(N)active sites optimizes the Ru d-band center and stabilizes intermediates,while Ru-N coordination enhances structural integrity.This study establishes a novel paradigm for designing robust acidic OER catalysts through defect and coordination engineering,bridging the gap between activity and stability for sustainable energy technologies.展开更多
Gibbons are small,arboreal apes that play a critical role in tropical biodiversity and ecosystem ecology.However,nearly all species of gibbons are threatened by habitat loss,illegal trade,hunting,and other human activ...Gibbons are small,arboreal apes that play a critical role in tropical biodiversity and ecosystem ecology.However,nearly all species of gibbons are threatened by habitat loss,illegal trade,hunting,and other human activities.Long-term poor understanding of their genetics and evolution undermines effective conservation efforts.In this study,we analyse comparative population genomic data of four Nomascus species.Our results reveal strong genetic differentiation and gene flow among Nomascus species.Additionally,we identify genomic features that are potentially related to natural selection linked to vocalization,fructose metabolism,motor balance,and body size,consistent with the unique phenotype and adaptability of gibbons.Inbreeding,coupled with population declines due to climate change and historical human activities,leads to reduced genetic diversity and the accumulation of deleterious variations that likely affect cardiovascular disease and the reproductive potential of gibbons and further reduce their fitness,highlighting the urgent need for effective conservation strategies.展开更多
Current quantitative characterization methods for the mechanical response and damage evolution of coal seams at different burial depths under mining-induced stress remains insufficient.To address this,this study estab...Current quantitative characterization methods for the mechanical response and damage evolution of coal seams at different burial depths under mining-induced stress remains insufficient.To address this,this study establishes a quantitative characterization model for the evolution of mechanical properties in gas-bearing coal masses at varying burial depths.It innovatively introduces a dual damage quantification technique and develops a coupled damage evolution model that comprehensively considers energy evolution,effective mining-induced stress,permeability,and a damage sensitivity coefficient,followed by extensive analysis.Key findings include:coal damage exhibits heterogeneous evolutionary characteristics under mining-induced stress;based on the theory of irreversible deformation,the proposed damage characterization equation can effectively determine the critical damage threshold of coal;the three-parameter EXP function model is more suitable for characterizing the time-dependent damage process of coal under mining-induced stress;a new characterization method for the coal brittleness evaluation index is proposed,revealing an 800 m burial depth boundary for the coal brittleness index;at the microscopic level,achieving quantitative characterization of the correlation between peak stress and the average reduction in functional groups during mining-induced failure of coal at different burial depths.Finally,the mapping relationship between laboratory experimental parameters and field monitoring indicators for early warning of coal mine dynamic disasters is established.展开更多
This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to ...This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to 2000 K.Two spallation modes emerge:classical spallation for shock velocity below 1.5 km/s,with solid-state reversible Body-Centered Cubic(BCC)to Face-Centered Cubic(FCC)orHexagonal Close-Packed(HCP)phase transformations and discrete void nucleation-coalescence;micro-spallation for shock velocity above 3.0 km/s,featuring complete shock-induced melting and fragmentation,with a transitional regime(2.0-2.5 km/s)of partial melting.Spall strength decreases monotonically with temperature due to thermal softening.Elevated temperatures delay void nucleation but increase density,expanding spall regions and enhancing structural disorder with reduced BCC recovery.For microspallation,melting exacerbates damage,causing smaller voids and intensified atomic ejection,which increases with temperature.Free surface velocity profiles indicate damage:in classical spallation,first drop marks nucleation,and pullback signals spall layers.In micro-spallation,the first drop is irrelevant,but remains valid.Temperature delays pullback signals and weakens Hugoniot Elastic Limit.This study clarifies temperature-shock coupling in Ta spallation,aiding failure prediction in high-temperature shock environments.展开更多
基金supported by the Natural Science Foundation of Heilongjiang Province,China(No.JQ2022E004)。
文摘To investigate the evolution of grain orientation and slip modes in magnesium alloys with multiple texture components,an AZ31 gradient-structured magnesium alloy sheet was fabricated using hard plate rolling(HPR).The changes in texture and slip modes under different reductions were examined.The results demonstrate that the AZ31 magnesium alloy sheets display a self-epitaxial gradient structure,with the best mechanical properties observed at rolling temperature of 673 K and reduction of 50%.Significant changes in texture type and strength are observed along the normal direction(ND)of the sheet.The coarse-grain region exhibits a bimodal texture aligned with the rolling direction.These texture variations enhance the stress distribution at the fine grain-coarse grain interface,influencing the grain orientation and the activation of different slip modes,thus improving the mechanical properties of gradient-structured magnesium alloy sheets.This approach offers a new strategy for the fabrication of high-performance magnesium alloy sheets.
基金Guangdong Basic and Applied Basic Research Foundation(2023B1515120050,2023A1515110529 and 2024A1515012454)Shenzhen Science and Technology Program(JCYJ20230807145759008 and KJZD20240903100206009).
文摘Acetolactate synthase(ALS)-targeting herbicides are among the most widely used weed-control chemicals globally.Mutations in the ALS gene can confer herbicide resistance in crops,thereby allowing selective elimination of weeds without harming crops.Herbicide-resistant ALS alleles were initially discovered in weeds and subsequently developed through artificial mutagenesis techniques.With the advancement of CRISPR/Cas technologies,various genome-editing tools are now available to introduce these resistant alleles,as well as novel variants,into diverse crop species.Moreover,emerging methodologies,such as directed evolution,enable the generation and screening of large populations of random ALS mutants.Consequently,ALS has become one of the most extensively targeted genes in plant gene evolution.This paper provides a comprehensive overview of both conventional and recently developed strategies for ALS evolution,with particular emphasis on CRISPR/Cas-based genome editing and directed evolution.Future perspectives on technological application are also discussed.By advancing our understanding of herbicide-resistant ALS allele development for crop improvement,these methodologies may also pave the way for their application to the evolution of other agronomically important genes.
基金National Natural Science Foundation of China(52065036,52365018)Natural Science Foundation of Gansu(23JRRA760,24JRRA175,25JRRA060)+1 种基金Hongliu Outstanding Youth Foundation of Lanzhou University of TechnologyLeading Innovative Talents Project of Changzhou(CQ20210111)。
文摘To elucidate the deformation mechanisms ofγ-TiAl,the nanoindentation experiments and crystal plasticity finite element(CPFE)simulation were employed to investigate the effects of crystal orientations and GBs on the mechanical properties ofγ-TiAl alloys.A crystal plasticity constitutive model was developed,and load-displacement curves,hardness,and Young's modulus were obtained for both single grains and GBs inγ-TiAl alloys.Based on the aforementioned model,this study investigated the distribution patterns of surface morphology around the indentation sites of individual grain and GBs.It also analyzed the cumulative shear strain distribution,slip system activation,and the interaction between GBs and dislocation slip for various crystal orientations.The results indicate that the mechanical response and pileup behavior exhibit significant anisotropy due to the interplay among the indenter geometry,material slip systems,and cumulative shear strain distribution.Moreover,the interaction between GBs and dislocation slip substantially alters dislocation distribution,thereby influencing material flow and playing a critical role in the mechanical response and plastic deformation of the material.
文摘A composite electrocatalyst,CoMoNiO-S/NF-110(NF is nickel foam),was synthesized through electrodeposition,followed by pyrolysis and then the vulcanization process.CoMoNiO-S/NF-110 exhibited a structure where Ni3S2 and Mo2S3 nanoparticles were integrated at the edges of Co3O4 nanosheets,creating a rich,heterogeneous interface that enhances the synergistic effects of each component.In an alkaline electrolyte,the synthesized CoMoNiO-S/NF-110 exhibited superior electrocatalytic performance for oxygen evolution reaction(OER),achieving current densities of 100 and 200 mA·cm^(-2) with low overpotentials of 199.4 and 224.4 mV,respectively,outperforming RuO2 and several high-performance Mo and Ni-based catalysts.This excellent performance is attributed to the rich interface formed between the components and active sites exposed by the defect structure.
基金National MCF Energy R&D Program of China(2018YFE0306100)Natural Science Foundation of Hunan Province for Distinguished Young Scholars(2021JJ10062)+1 种基金National Natural Science Foundation of China(52101028)China Postdoctoral Science Foundation(2021M703628)。
文摘Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under different deposition rates and grain orientations.The evolution of grain morphology and grain orientation was also taken into consideration.Simulation results show that at lower deposition rates,the surface of the formed Ti film exhibits a distinct oriented texture structure.The surface roughness of the Ti film is positively correlated with the grain misorientation.Moreover,the surface roughness obtained from the simulation is in good agreement with the experiment results.
文摘The poor electrical conductivity of metal-organic frameworks(MOFs)limits their electrocatalytic performance in the oxygen evolution reaction(OER).In this study,a Py@Co-MOF composite material based on pyrene(Py)molecules and{[Co2(BINDI)(DMA)_(2)]·DMA}_(n)(Co-MOF,H4BINDI=N,N'-bis(5-isophthalic acid)naphthalenediimide,DMA=N,N-dimethylacetamide)was synthesized via a one-pot method,leveragingπ-πinteractions between pyrene and Co-MOF to modulate electrical conductivity.Results demonstrate that the Py@Co-MOF catalyst exhibited significantly enhanced OER performance compared to pure Co-MOF or pyrene-based electrodes,achieving an overpotential of 246 mV at a current density of 10 mA·cm^(-2) along with excellent stability.Density functional theory(DFT)calculations reveal that the formation of O*in the second step is the rate-determining step(RDS)during the OER process on Co-MOF,with an energy barrier of 0.85 eV due to the weak adsorption affinity of the OH*intermediate for Co sites.CCDC:2419276.
文摘The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.
文摘While methodology for determining the mode of evolution in coding sequences has been well established,evaluation of adaptation events in emerging types of phenotype data needs further development.Here,we propose an analysis framework(expression variance decomposition,EVaDe)for comparative single-cell expression data based on phenotypic evolution theory.After decomposing the gene expression variance into separate components,we use two strategies to identify genes exhibiting large between-taxon expression divergence and small within-cell-type expression noise in certain cell types,attributing this pattern to putative adaptive evolution.In a dataset of primate prefrontal cortex,we find that such humanspecific key genes enrich with neurodevelopment-related functions,while most other genes exhibit neutral evolution patterns.Specific neuron types are found to harbor more of these key genes than other cell types,thus likely to have experienced more extensive adaptation.Reassuringly,at the molecular sequence level,the key genes are significantly associated with the rapidly evolving conserved non-coding elements.An additional case analysis comparing the naked mole-rat(NMR)with the mouse suggests that innateimmunity-related genes and cell types have undergone putative expression adaptation in NMR.Overall,the EVaDe framework may effectively probe adaptive evolution mode in single-cell expression data.
基金supported by the National Nature Science Foundation of China under Grant No.11902332。
文摘The augmented evolution equation is established under the framework of the Variation Evolving Method(VEM)that seeks optimal solutions by solving the transformed Initial-Value Problems(IVPs).To improve the numerical performance,its compact form is developed herein.Through replacing the states and costates variation evolution with that of the controls,the dimension-reduced Evolution Partial Differential Equation(EPDE)only solves the control variables along the variation time to get the optimal solution,and the initial conditions for the definite solution may be arbitrary.With this equation,the scale of the resulting IVPs,obtained via the semi-discrete method,is significantly reduced and they may be solved with common Ordinary Differential Equation(ODE)integration methods conveniently.Meanwhile,the state and the costate dynamics share consistent stability in the numerical computation and this avoids the intrinsic numerical difficulty as in the indirect methods.Numerical examples are solved and it is shown that the compact form evolution equation outperforms the primary form in the precision,and the efficiency may be higher for the dense discretization.Actually,it is uncovered that the compact form of the augmented evolution equation is a continuous realization of the Newton type iteration mechanism.
基金supported by the Natural Science Foundation of Anhui Province in China(2508085MF166)Research Fund of Anhui Institute of Translational Medicine(2024zh-03)+2 种基金Key Scientific Research Foundation of Education Department of Anhui Province(2023AH040083)National Natural Science Foundation of China(12404353)Cultivation Project of Training Young and Middle-aged Teachers in Universities of Anhui Province(DTR2023013).
文摘Optical tweezers technology has the characteristics of noncontact manipulation in three dimensions and steerable separation in solutions,and could be applied to obtain a separated sperm with high quality for intracytoplasmic sperm injection(ICSI).However,the effects of optical tweezers on sperm motility are still unclear.To elucidate the effects on sperm motility for optical tweezers,we systematically investigated the correlation between motility parameters and the parameters of optical tweezers(wavelength,power,trapping duration,and trapping orientation).Under three systems of optical tweezers with different laser wavelengths(1064,850,and 785 nm),the nine motility parameters of free swimming were mainly affected by trapping orientation(vertical/horizontal)and trapping duration.When 850 nm laser and 1064 nm laser are used,vertical trapping significantly reduces sperm free-swimming capability with prolonged exposure time,whereas horizontal trapping exhibits relatively minor interference on sperm motility.Notably,the 785 nm laser does not induce statistically significant changes in key parameters of sperm motility under any experimental conditions(trapping orientation and duration).For the rolling frequency of trapped sperm,horizontal trapping for three wavelengths has a negligible effect compared with vertical trapping,especially for the 785 nm laser.In conclusion,horizontal trapping can preserve sperm motility under low power(below 140mW at 1064 nm,below 100mW at 850nm,below 60mW at 785 nm)and short duration(below 4 min).This trapping duration is suffcient for the separation procedure of single live sperm in ICSI.This study provides critical parameter optimization guidelines for the safe application of optical tweezers technology in reproductive medicine.
基金supported by 2024 The Basic Ability Improvement Project for Young and Middle-aged Teachers of Colleges and Universities in Guangxi(No.2024KY0165)2024 Guangxi Minzu University General Research Project(Humanities and Social Sciences Category,No.2024MDSKYB20)2022 Annual Teaching and Research Project of Shiyuan College of Nanning Normal University(No.2022JY13).
文摘Objectives:Non-suicidal self-injury(NSSI)represents a prominent and escalating concern within mental health,associated with considerable psychological and physical dangers.Peer victimization is identified as a significant predictor of NSSI behavior.Although prior research has explored the association between peer victimization and NSSI,the mechanisms underlying this relationship remain insufficiently understood.Utilizing social information processing theory frameworks,the present study seeks to examine the sequential mediating roles of a cognitive factor,future orientation,and a behavioral factor,social withdrawal,in middle school students.Methods:A cross-sectional survey was administered in China,involving 528 participants(261 females and 267 males;Meanage=13.71,standard deviation[SD]=0.93).Participants completed self-report measures assessing peer victimization via the Delaware Bullying Victimization Scale-Student Version,NSSI via the Adolescents Self-Harm Scale,future orientation via the Adolescent Future Orientation Questionnaire,and social withdrawal via the Social Withdrawal Questionnaire.Results:Findings indicated a significant positive correlation between peer victimization and NSSI(r=0.30,p<0.01).Additionally,future orientation and social withdrawal functioned as serial mediators,with an indirect effect of 0.01(95%CI:[0.01,0.02]),representing 2.70%of the total effect(𝛽=0.37,95%CI:[0.25,0.47]).Conclusions:The findings endorse a theoretical framework in which negative future outlook and social withdrawal are sequentially linked within the relationship between peer victimization and NSSI.Although the serial indirect effect observed is modest,it delineates a distinct associative pattern that characterizes adolescents subjected to victimization.These results carry practical significance for school-based intervention programs,indicating that targeting future perspectives and social connections may enhance strategies for preventing NSSI.
基金supported by the National Key Research and Development Program of China(2021YFA1200203)the National Natural Science Foundation of China(Nos.52371097,51922026,52301136)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.X2025003201,N25QNR005 and N25ZLE004)the Youth Science Foundation Project(Category A)of Liaoning Province(No.2025JH6/101100006).
文摘Magnesium alloys usually exhibit poor ductility because of their limited slip systems at room temperature.To overcome this intrinsic limitation,heterostructure design has emerged as an effective strategy for enhancing their mechanical performance,yet the development of orientation-based heterogeneous magnesium alloys remains relatively unexplored.In this work,by varying the triaxial cyclic compression(TCC)applied to an extruded Mg-2.9Y(wt.%)alloy,we obtained two materials that possessed comparable bimodal grain-size characteristics but showed notable differences in orientation heterogeneity.The material processed by TCC along three orthogonal directions for five complete cycles exhibited a predominantly hard orientation,with hard refined grains embedded within coarse grains of the same hard orientation.By applying an additional compression to plane A,the other material mainly comprising the soft orientation was obtained,with hard-oriented refined grains embedded in soft-oriented coarse grains.These materials exhibited quite different tensile properties and work hardening abilities.By combining microstructural characterization and crystal plasticity modeling,deformation micromechanism of the materials under tensile loading was explored.In the former,poor deformation coordination between the different domains led to strain localization in the refined grain region.However,the latter experienced a significant orientation transition due to tensile twinning.This promoted non-basalslip and improved deformation compatibility,resulting in the more persistent hetero-deformation induced hardening.These findings provide fundamental insights into the micromechanical behavior of heterostructured alloys and offer a new strategy for designing high-performance hexagonal close-packed materials by introducing heterogeneous orientation distributions.
基金supported by startup funding from Huazhong University of Science and Technology.
文摘Zinc oxide(ZnO)films,as representative piezoelectric semiconductors,have garnered considerable interest in ultrasonic testing.Current research challenges include maintaining the consistency of continuous c-axis orientation and determining the fundamental link between the electrical structure and piezoelectric response.Accordingly,we have proposed ZnO films incorporated with an orientation-inducing layer(OIL),utilizing orientation induction and rapid deposition technology to regulate the growth structure of the ZnO films.Furthermore,the influence of the competitive mechanism between the film growth and lateral diffusion on the film's growth structure has been investigated.Piezoelectric force microscopy(PFM)analysis demonstrated the regulation and enhancement of ZnO piezoelectric polarization by the OIL.The enhancement mechanism of OIL on film performance was revealed via experimental examination of the film structure,morphology,crystallization orientation,oxygen vacancies,carrier concentration,band structure,and density of states based on density functional theory(DFT).Benefiting from the superior electromechanical response of the ZnO OIL sensor,characterized by fast response recovery times of 2.4 ms/7.7 ms and a sensitivity of 1.09 V/N,the device has successfully demonstrated practical applications in both motion pressure detection and bolt axial force measurement.These findings provide new insights into the ultrasonic detection for aerospace applications of ZnO OIL piezoelectric devices and demonstrate significant potential for health monitoring in connection systems.
基金Supported by the National Natural Science Foundation of China(No.32170204)。
文摘This study presents a comprehensive phylogenetic analysis on Batrachospermaceae based on key taxonomic identifiers(rbcL,psaA,psbA,and COI-5P)from some genera.To systematically explore the phylogenetic relationships and taxonomy within Batrachospermaceae,we integrated molecular and morphological data,and explored the phylogeny,character evolution,and ancestral geographical origin and provided a theoretical support for the classification and geographic origination of Batrachospermaceae.Our findings reveal distinct relationships within the phylogenetic tree.Notably,10 genera(Sirodotia,Batrachospermum,Tuomeya,Volatus,Lympha,Nothocladus,Torularia,Sheathia,Nocturama,and Petrohua)are closely associated in the rbcL phylogenetic tree.Additionally,four genera(Kumanoa,Hoefkenia,Notohesperus,and Virescentia)exhibit high support ratios,indicating their close interrelations.Other genera,including Paludicola,Visia,Acarposporophycos,Macrosporophycos,Visioidea,Balliopsis,and Psilosiphon,exhibit clustering traits.Furthermore,the multigene sequences provide a robust support for Montagnia that forms a monophyletic group.Ancestral reconstruction of morphological characters identifies nine primitive character states,including whorl,fascicle length,cortical cells,secondary fascicles,the shape of carpogonical branch,spermatangia,carposporophyte,carpogonium and trichogyne,with Visia likely representing ancestral traits in Batrachospermaceae.Furthermore,geographical origin maps suggest a potential common ancestral of Batrachospermaceae origin in the American continent.Additional to conventional analyses,including evolutionary and ancestral reconstruction investigations into key morphological characters,we attempt to reconstruct the biogeography within the Batrachospermaceae,thus contributing to a nuanced understanding of its origin.
基金financially supported by the National Science and Technology Major Project of China(No.2019-VII-0019-0161 and No.2019-VII-0004-0144)the National Natural Science Foundation of China(No.92360302)the Shandong Provincial Natural Science Foundation of China(No.ZR2021QE103)。
文摘Turbine blades,due to their intricate geometry,are exposed to multiaxial stresses during operation.Consequently,it is imperative to examine the anisotropy of their stress-rupture behavior across various testing scenarios,particularly under high-temperature conditions.Stress-rupture behavior of a Ni-based single crystal superalloy was investigated under a load varying from 100 MPa to 137 MPa at 1,100℃ for both[001]-and[111]-orientated specimens.Results demonstrate that the rupture behavior of[111]-orientated specimens exhibits obviously higher sensitive to applied stress compared to[001]-orientated specimens.This difference is primarily attributed to the orientation dependentγ'coarsening behavior and distinct dislocation interactions atγ/γ'interfaces.In[001]-oriented specimens,plate-likeγ/γ'rafts rapidly form alongside well-developed interfacial dislocation networks,where theγ/γ'misfit stress dominates the microstructural evolution.In contrast,the[111]-orientated specimens exhibit retained,coarsenedγ'precipitates embedded within theγmatrix,accompanied by poorly developed interfacial dislocation networks.
基金supported by the National Natural Science Foundation of China (No.52274304)。
文摘Developing catalysts with excellent stability while significantly reducing the overpotential of the oxygen evolution reaction(OER) is crucial for advancing overall water splitting(OWS) systems.In this study,we synthesized the electrode material Ce-NiCo-LDHs@SnO_(2)/NF through a two-step hydrothermal reaction,where Ce-doped NiCo-LDHs are grown on nickel foam modified by a SnO_(2) layer.Ce doping adjusts the internal electronic distribution of Ni Co-LDHs,while the introduction of the SnO_(2) layer enhances electron transfer capability.Together,these factors contribute to the reduction of the OER energy barrier and experimental evidence confirms that the reaction proceeds via the lattice oxygen evolution mechanism(LOM).Consequently,Ce-NiCo-LDHs@SnO_(2)/NF exhibits high level electrochemical performance in OER,requiring only 234 m V overpotential to achieve a current density of 10 m A/cm^(2),with a Tafel slope of just 27.39 m V/dec.When paired with Pt/C/NF,an external potential of only 1.54 V is needed to drive OWS to attain a current density amounting to 10 m A/cm^(2).Furthermore,the catalyst demonstrates stability for 100 h during the OWS stability test.This study underscores the feasibility of enhancing the OER performance through Ce doping and the introduction of a conductive SnO_(2) layer.
基金support from the National Natural Science Foundation of China(Nos.12305373 and 52276220)the Guangzhou Basic Research Program(No.SL2024A04J00234).
文摘Developing efficient and durable electrocatalysts for acidic oxygen evolution reaction(OER)is pivotal for advancing proton exchange membrane water electrolysis(PEMWEs),yet balancing activity and stability remains a formidable challenge.Herein,we propose a dual-engineering strategy to stabilize Ru-based catalysts by synergizing the oxygen vacancy site-synergized mechanism-lattice oxygen mechanism(OVSM-LOM)with Ru-N bond stabilization.The engineered RuO_(2)@NCC catalyst exhibits exceptional OER performance in 0.5 M H2SO4,achieving an ultralow overpotential of 215 mV at 10 mA cm^(-2) and prolonged stability for over 327 h.The catalyst delivers 300 h of continuous operation at 1 A cm^(-2),with a negligible degradation rate of only 0.067 mV h-1,further demonstrating its potential for practical application.Oxygen vacancies unlock the OVSM-LOM pathway,bypassing the sluggish adsorbate evolution mechanism(AEM)and accelerating reaction kinetics,while the Ru-N bonds suppress Ru dissolution by anchoring low-valent Ru centers.Quasi-in situ X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),and isotopic labeling experiments confirm the lattice oxygen participation with *O formation as the rate-determining step.The Ru-N bonds reinforce the structural integrity by stabilizing low-valent Ru centers and inhibiting overoxidation.Theoretical calculations further verify that the synergistic interaction between OVs and Ru-O(N)active sites optimizes the Ru d-band center and stabilizes intermediates,while Ru-N coordination enhances structural integrity.This study establishes a novel paradigm for designing robust acidic OER catalysts through defect and coordination engineering,bridging the gap between activity and stability for sustainable energy technologies.
基金supported by Science and Technology Program from the Forestry Administration of Guangdong Province(2024KJQT0012)the Guangdong Provincial Key R&D Program(2022B1111040001)+2 种基金the National Forestry Administration rare and endangered species field rescue and breeding project(Gui lin hu yu O10)the National Natural Science Foundation of China(32200337)a fellowship from the China Postdoctoral Science Foundation(2022M712003).
文摘Gibbons are small,arboreal apes that play a critical role in tropical biodiversity and ecosystem ecology.However,nearly all species of gibbons are threatened by habitat loss,illegal trade,hunting,and other human activities.Long-term poor understanding of their genetics and evolution undermines effective conservation efforts.In this study,we analyse comparative population genomic data of four Nomascus species.Our results reveal strong genetic differentiation and gene flow among Nomascus species.Additionally,we identify genomic features that are potentially related to natural selection linked to vocalization,fructose metabolism,motor balance,and body size,consistent with the unique phenotype and adaptability of gibbons.Inbreeding,coupled with population declines due to climate change and historical human activities,leads to reduced genetic diversity and the accumulation of deleterious variations that likely affect cardiovascular disease and the reproductive potential of gibbons and further reduce their fitness,highlighting the urgent need for effective conservation strategies.
文摘Current quantitative characterization methods for the mechanical response and damage evolution of coal seams at different burial depths under mining-induced stress remains insufficient.To address this,this study establishes a quantitative characterization model for the evolution of mechanical properties in gas-bearing coal masses at varying burial depths.It innovatively introduces a dual damage quantification technique and develops a coupled damage evolution model that comprehensively considers energy evolution,effective mining-induced stress,permeability,and a damage sensitivity coefficient,followed by extensive analysis.Key findings include:coal damage exhibits heterogeneous evolutionary characteristics under mining-induced stress;based on the theory of irreversible deformation,the proposed damage characterization equation can effectively determine the critical damage threshold of coal;the three-parameter EXP function model is more suitable for characterizing the time-dependent damage process of coal under mining-induced stress;a new characterization method for the coal brittleness evaluation index is proposed,revealing an 800 m burial depth boundary for the coal brittleness index;at the microscopic level,achieving quantitative characterization of the correlation between peak stress and the average reduction in functional groups during mining-induced failure of coal at different burial depths.Finally,the mapping relationship between laboratory experimental parameters and field monitoring indicators for early warning of coal mine dynamic disasters is established.
基金funded by the Changsha Municipal Natural Science Foundation(Grant No.kq2402024)Chengdu Polytechnic Scientific Research Platform(23KYPT01).
文摘This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to 2000 K.Two spallation modes emerge:classical spallation for shock velocity below 1.5 km/s,with solid-state reversible Body-Centered Cubic(BCC)to Face-Centered Cubic(FCC)orHexagonal Close-Packed(HCP)phase transformations and discrete void nucleation-coalescence;micro-spallation for shock velocity above 3.0 km/s,featuring complete shock-induced melting and fragmentation,with a transitional regime(2.0-2.5 km/s)of partial melting.Spall strength decreases monotonically with temperature due to thermal softening.Elevated temperatures delay void nucleation but increase density,expanding spall regions and enhancing structural disorder with reduced BCC recovery.For microspallation,melting exacerbates damage,causing smaller voids and intensified atomic ejection,which increases with temperature.Free surface velocity profiles indicate damage:in classical spallation,first drop marks nucleation,and pullback signals spall layers.In micro-spallation,the first drop is irrelevant,but remains valid.Temperature delays pullback signals and weakens Hugoniot Elastic Limit.This study clarifies temperature-shock coupling in Ta spallation,aiding failure prediction in high-temperature shock environments.
