Zinc-based batteries(ZBBs)have garnered significant attention in the field of energy storage and conversion owing to their exceptional advantages,including high energy density,intrinsic environmental benignity,low mat...Zinc-based batteries(ZBBs)have garnered significant attention in the field of energy storage and conversion owing to their exceptional advantages,including high energy density,intrinsic environmental benignity,low material cost,as well as enhanced safety characteristics.Nevertheless,several critical challenges persist,predominantly the propensity for dendrite growth,inherent kinetic limitations,deleterious electrode side reactions,and perplexing shuttle effects,which collectively impede the practical implementation and commercial viability of ZBBs.In this context,fibers fabricated via electrospinning technology exhibit remarkable advantages in terms of enhanced specific surface area,improved electrical conductivity,and superior mechanical integrity,while also affording optimized pore structures.These unique features render electrospinning fibers particularly promising for addressing the key issues that limit ZBBs performance,including energy density,charge/discharge rate capabilities,and cycling stability.So,it is very necessary to summarize electrospinning technology application in ZBBs.This paper firstly analyzes the fundamental mechanisms and inherent challenges of ZBBs including zincion,zinc-air,and zinc-halide batteries.Subsequently,the application of electrospinning fiber structures in anodes,cathodes,separators,and electrolytes optimization for ZBBs is summarized.Finally,the prospect of electrospinning technology in ZBBs is envisioned,and existing challenges are presented for its further application.展开更多
Silicon carbide(SiC)ceramics are extensively utilized in aerospace,national defense,and petrochemical industries due to their superior physical and chemical properties.The processing of bulk SiC ceramics necessitates ...Silicon carbide(SiC)ceramics are extensively utilized in aerospace,national defense,and petrochemical industries due to their superior physical and chemical properties.The processing of bulk SiC ceramics necessitates precise and efficient grinding techniques to produce components with satisfactory functionality.However,the inherent high hardness and brittleness of SiC ceramics present significant challenges during grinding,leading to severe brittle fracture and tool wear that compromise both surface integrity and production efficiency.Although ductile-regime grinding of SiC ceramics can be achieved by enhancing machine tool accuracy and stiffness while optimizing wheel performance alongside appropriate selection of process parameters,a comprehensive summary of the mechanisms underlying damage evolution during grinding is lacking,and a mature grinding process for SiC ceramics has yet to be developed.To bridge this gap,the sintering technologies,mechanical properties,and microstructures of SiC ceramics were briefly covered.The grinding-induced damage mechanism and low-damage grinding technologies of SiC ceramics were summarized.The fundamental science underlying the ductile deformation and removal mechanisms of brittle solids was emphasized.Additionally,attention was directed towards the critical role of hybrid energy field grinding in minimizing brittle damages and promoting removal efficiency.This review not only elucidates the intrinsic interactions between the work material and abrasives,but also offers valuable insights for optimizing the grinding processes of brittle solids.展开更多
Obtaining high-quality 10000-meter-deep seafloor sediment samples is the prerequisite and foundation for conducting deep-sea geological and environmental scientific research.The bottom structure of the deep seafloor i...Obtaining high-quality 10000-meter-deep seafloor sediment samples is the prerequisite and foundation for conducting deep-sea geological and environmental scientific research.The bottom structure of the deep seafloor is complex,and the physical and mechanical properties and disturbance resistance of sediments of different lithologies vary greatly,so the sediment sampler inevitably disturbs the sediments during the sampling process and affects the quality of the sediment samples.A new type of deep-sea sediment pressure retaining sampler is introduced,the force state and elastic–plastic state of the sampler destroying sediments are analyzed,the radial disturbance model of sediment coring based on the spherical cavity expansion theory is established,and the radius of sediments undergoing plastic deformation around the spherical holes is used as an index for evaluating the radial disturbance of sediments.The distribution of stress and strain fields in the sediments during the expansion of the spherical cavity and the influencing factors of the radius of the radially disturbed region(plastic region)are analyzed using an arithmetic example,and the influence law is analyzed.A sediment disturbance experimental platform was built indoors to simulate the sediment coring process.The radial stress field and pore water pressure of the sediment during the coring process were monitored by sensors arranged inside the sediment,and the results of indoor tests verified the correctness of the perturbation theory model.The sampler was carried aboard the deep-sea manned submersible FENDOUZHE and conducted on-site tests at depths of 9298.4 and 9142.8 m in the Kuril-Kamchatka Trench.Pressure-preserved sediment samples were retrieved,with preservation rates of 94.21%and 92.02%,respectively,which are much higher than the current technical indicator of 80%of pressure-holding ratio for deep-sea sediments.The retrieved sediments have obvious stratification characteristics and little disturbance.展开更多
Aboveground biomass(AGB)and belowground biomass(BGB)are key components of carbon storage,yet their responses to future climate changes remain poorly understood,particularly in China.Understanding these dynamics is ess...Aboveground biomass(AGB)and belowground biomass(BGB)are key components of carbon storage,yet their responses to future climate changes remain poorly understood,particularly in China.Understanding these dynamics is essential for global carbon cycle modeling and ecosystem management.This study integrates field observations,machine learning,and multi-source remote sensing data to reconstruct the distributions of AGB and BGB in China from 2000 to 2020.Then CMIP6 was used to predict the distribution of China under three SSP scenarios(SSP1-1.9,SSP2-4.5,SSP5-8.5)from 2020 to 2100 to fill the existing knowledge gap.The predictive accuracy for AGB(R^(2)=0.85)was significantly higher than for BGB(R^(2)=0.48),likely due to the greater complexity of modeling belowground dynamics.NDVI(Normalized Difference Vegetation Index)and soil organic carbon density(SOC)were identified as the primary drivers of AGB and BGB changes.During 2000-2020,AGB in China remained stable at approximately 10.69 Pg C,while BGB was around 5.06 Pg C.Forest ecosystems contributed 88.52% of AGB and 43.83% of BGB.AGB showed a relatively slow annual increase,while BGB demonstrated a significant annual growth rate of approximately 37 Tg C yr^(−1).Under the low-emission scenario,both AGB and BGB show fluctuations and steady growth,particularly in South China and the northwestern part of Northeast China.Under the moderate-emission scenario,AGB and BGB show significant declines and increases,respectively.In the high-emission scenario,both AGB and BGB decline significantly,particularly in the southwestern and central regions.These results provide valuable insights into ecosystem carbon dynamics under climate change,emphasizing the relatively low responsiveness of AGB and BGB to climatic variability,and offering guidance for sustainable land use and management strategies.展开更多
The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique natu...The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique nature of this soil type.In this study,a series of unconfined compression tests were carried out on unsaturated CWG soil in an underground engineering site,and the effects of varying the environmental variables on the main undrained mechanical properties were analyzed.Based on the experimental results,a novel constitutive model was then established using the damage mechanics theory and the undetermined coefficient method.The results demonstrate that the curves of remolded CWG specimens with different moisture contents and dry densities exhibited diverse characteristics,including brittleness,significant softening,and ductility.As a typical indicator,the unconfined compression strength of soil specimens initially increased with an increase in moisture content and then decreased.Meanwhile,an optimal moisture content of approximately 10.5%could be observed,while a critical moisture content value of 13.0%was identified,beyond which the strength of the specimen decreases sharply.Moreover,the deformation and fracture of CWG specimens were predominantly caused by shear failure,and the ultimate failure modes were primarily influenced by moisture content rather than dry density.Furthermore,by comparing several similar models and the experimental data,the proposed model could accurately replicate the undrained mechanical characteristics of unsaturated CWG soil,and quantitatively describe the key mechanical indexes.These findings offer a valuable reference point for understanding the underlying mechanisms,anticipating potential risks,and implementing effective control measures in similar underground engineering projects.展开更多
In this paper, introducing new remote sensing and geographic information technology to solve the problem of data collection and analysis, this makes the study of ecological risk assessment very quick and accurate. Tak...In this paper, introducing new remote sensing and geographic information technology to solve the problem of data collection and analysis, this makes the study of ecological risk assessment very quick and accurate. Taking the Shan Xin mining area of the tin mine in Lengshuijiang of Hunan Province as the research object, using the remote sensing image data of three periods in 2005, 2010 and 2015, the remote sensing image is classified carefully and the landscape classification map of the mining area is obtained. The ecological risk index is introduced and the ecological risk values are sampled and interpolated on the ArcGIS platform. The ecological risk spatial distribution map based on the landscape pattern index was obtained. The ecological risk was divided into 5 levels by using the Jenks natural classification method, and each ecological risk grade area was counted. The research results show that: from year 2005 to year 2010, landscape ecological risk trend of the mining area is growing up;the trend rising area of landscape ecological risk is mainly in the southwest and northeast of the Shan Xin mining field;the area of higher and high ecological risk is increasing year by year;and the trend of dispersed development in space is obvious;the development trend of ecological risk in the mining area is rapidly increasing;in 2010 - 2015, the higher and high ecological risk area decrease slightly with the increasing of area of grassland and residential low vulnerability of landscape types;the ecological risk area showed a slow decreasing trend. The research results provide an objective reference for decision making of ecological environment governance.展开更多
The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monit...The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.展开更多
Based on engineering practices of Wuyang Coal Mine, we carried out X-ray diffract researches on No. 3 coal; and the rocks of its roof and floor by XRD meter, and simulated the interactive effect of the surrounding roc...Based on engineering practices of Wuyang Coal Mine, we carried out X-ray diffract researches on No. 3 coal; and the rocks of its roof and floor by XRD meter, and simulated the interactive effect of the surrounding rock deformation by FLAC2DS.0 numerical simulation software under the condition of different tunneling method of multimine roadway in parallel. The internal structures of the surrounding rocks of 76 belt roadway were monitored by borehole observation instruments： and then, we analyzed the reason of fhilure and deformation of surrounding rocks of several rise entry, and proposed the technical mea- sures for controlling interactive effect of several rise entry surrounding rock deformation at last. For the thickness seam rise roadway, two conclusions were drawn： one is that the co-deformation among roadway groups mainly reflect on that both shear failure and deformation in coal pillar among roadways have decreased the width of pillar core region and clamping action of coal pillar to roof strata, increased the actual span of roof strata, intensified the flexural failure of roof strata and prized the bed separation of roof deep rock strata. The other conclusion is that the factors controlling the interactive deformation among roadways is obvious when appropriate re-adjustment in construction sequence of the tunneling of multimine parallel roadways because the construction sequence among roadways also has great effects on deformation of the surrounding rock in roadway.展开更多
The sulfate-reducing bacteria(SRB)corrosion of H70 brass,H80 brass and T2 copper was systematically studied using microstructure characterizations and electrochemical measurements.The results showed that H70 brass,H80...The sulfate-reducing bacteria(SRB)corrosion of H70 brass,H80 brass and T2 copper was systematically studied using microstructure characterizations and electrochemical measurements.The results showed that H70 brass,H80 brass and T2 copper exhibited good corrosion resistance in the sterile environment,and the corrosion products were mainly metal oxides,such as Cu_(2)O,CuO and ZnO.The SRB metabolism sharply accelerated the corrosion process of three types of copper alloys,especially the T2 copper.In the inoculated environment,an additional mixture of Cu_(2)S,ZnS and CuSO_(4)existed in the corrosion products.Pitting corrosion was the main corrosion style for the H70 brass and H80 brass,while general corrosion and pitting corrosion simultaneously dominated the corrosion process of the T2 copper in this environment.The results provide a new insight to the microbiological corrosion of copper alloys.展开更多
Memristor chaotic research has become a hotspot in the academic world.However,there is little exploration combining memristor and stochastic resonance,and the correlation research between chaos and stochastic resonanc...Memristor chaotic research has become a hotspot in the academic world.However,there is little exploration combining memristor and stochastic resonance,and the correlation research between chaos and stochastic resonance is still in the preliminary stage.In this paper,we focus on the stochastic resonance induced by memristor chaos,which enhances the dynamics of chaotic systems through the introduction of memristor and induces memristor stochastic resonance under certain conditions.First,the memristor chaos model is constructed,and the memristor stochastic resonance model is constructed by adjusting the parameters of the memristor chaos model.Second,the combination of dynamic analysis and experimental verification is used to analyze the memristor stochastic resonance and to investigate the trend of the output signal of the system under different amplitudes of the input signal.Finally,the practicality and reliability of the constructed model are further verified through the design and testing of the analog circuit,which provides strong support for the practical application of the memristor chaos-induced stochastic resonance model.展开更多
To accurately acquire deep-sea live biological samples,a hydraulic suction macro-biological pressure-retaining sampler(HSMPS)was designed to achieve active capture of seafloor biological by a suction pump.The complex ...To accurately acquire deep-sea live biological samples,a hydraulic suction macro-biological pressure-retaining sampler(HSMPS)was designed to achieve active capture of seafloor biological by a suction pump.The complex flow fields of deep-sea biologicals at three different locations were simulated.The deep-sea biologicals cause the flow field pressure and velocity to rise at different locations of the sampler,and the magnitude of the rise varies at different locations.The internal flow properties of the sampler were analyzed for different pumping flow rates the sampler.When the flow rate of the sampler pump was greater than 14 m3/h,the velocity of the inlet of the inflow area was greater than the limiting velocity of the deep-sea biologicals.The pumping test of deep-sea biologicals pumping sampler was carried out in the laboratory,and the test results were basically consistent with the simulation analysis.In order to balance the deep-sea biologicals damage and escape rate,the pumping flow of the sampler should be controlled between 14 and 16 m3/h.The test results provide a theoretical basis for the design of deep-sea biologicals sampling equipment.展开更多
This study investigates the nonlinear resonance responses of suspended cables subjected to multi-frequency excitations and time-delayed feedback.Two specific combinations and simultaneous resonances are selected for d...This study investigates the nonlinear resonance responses of suspended cables subjected to multi-frequency excitations and time-delayed feedback.Two specific combinations and simultaneous resonances are selected for detailed examination.Initially,utilizing Hamilton’s variational principle,a nonlinear vibration control model of suspended cables under multi-frequency excitations and longitudinal time-delayed velocity feedback is developed,and the Galerkin method is employed to obtain the discrete model.Subsequently,focusing solely on single-mode discretization,analytical solutions for the two simultaneous resonances are derived using the method of multiple scales.The frequency response equations are derived,and the stability analysis is presented for two simultaneous resonance cases.The results demonstrate that suspended cables exhibit complex nonlinearity under multi-frequency excitations.Multiple solutions under multi-frequency excitation can be distinguished through the frequency–response and the detuning-phase curves.By adjusting the control gain and time delay,the resonance range,response amplitude,and phase of suspended cables can be modified.展开更多
Brassica clubroot caused by Plasmodiophora brassicae has been identified as a severe soil-borne disease that poses a significant threat to plants root systems.The disease results in the formation of tumorous enlargeme...Brassica clubroot caused by Plasmodiophora brassicae has been identified as a severe soil-borne disease that poses a significant threat to plants root systems.The disease results in the formation of tumorous enlargements in the roots,leading to wilting and eventual plant death.Consequently,crop yield is drastically reduced,causing substantial economic losses in agriculture.The current study aims to provide a comprehensive overview of recent research process on Brassica clubroot,focusing on the biological characteristics,physiological race identification,and pathogenic mechanism of P.brassicae.Furthermore,it covers the latest advancements in the comprehensive prevention and clubroot control.The insights gained from this study are expected to contribute to the future research on clubroot and the development of resistance breeding strategies.展开更多
By combining neuroevolution potential(NEP)with phonon Boltzmann transport theory,we systematically investigate the thermal transport properties of three two-dimensional(2D)narrow bandgap semiconductors:Ca_(3)N_(2),Ba_...By combining neuroevolution potential(NEP)with phonon Boltzmann transport theory,we systematically investigate the thermal transport properties of three two-dimensional(2D)narrow bandgap semiconductors:Ca_(3)N_(2),Ba_(3)P_(2),and Ba_(3)As_(2).The room-temperature lattice thermal conductivities(κ_(L))of Ca_(3)N_(2),Ba_(3)P_(2),and Ba_(3)As_(2)considering only three-phonon scattering are 6.60 W/m K,11.90 W/m K,and 8.88 W/m K,respectively.When taking into account the higherorder phonon(four-phonon)scattering processes,theκL of these three materials decrease to 6.12 W/m K,9.73 W/m K and6.77 W/m K,respectively.Among these systems,Ba_(3)As_(2)undergoes the most pronounced suppression with a reduction of 23.8%.This is mainly due to the greater scattering phase space which enhances the four-phonon scattering.Meanwhile,it is revealed that unlike the traditional evaluation using the P_(4)/P_(3)ratio as an indicator of the strength of four-phonon interactions,the thermal conductivity of Ba_(3)P_(2)exhibits weaker four-phonon suppression behavior compared to Ba_(3)As_(2),despite hosting a higher P_(4)/P_(3)ratio.That is to say,the strength of four-phonon scattering cannot be evaluated solely by the ratio of P_(4)/P_(3).These results presented in this work shed light on the thermal transport properties of such new 2D semiconductors with narrow bandgaps.展开更多
Organic matter(OM)is the primary gas occurrence carrier in shale reservoirs due to their abundant nanopores.To reveal the OM pore structure,adsorption capacity and evolution during thermal maturation,this study collec...Organic matter(OM)is the primary gas occurrence carrier in shale reservoirs due to their abundant nanopores.To reveal the OM pore structure,adsorption capacity and evolution during thermal maturation,this study collected data from samples spanning the entire evolution stage,from immature to over-mature.Scanning Electron Microscope(SEM)observation and low temperature gases adsorption experiments were used to qualitatively-semi-quantitatively and quantitatively analyze OM pore structure evolution,and CH_(4) isothermal adsorption experiments were used to reveal the adsorption capacity evolution.Then,the influence and mechanism of matu rity and hydrocarbon generation on pore development and adsorption capacity were quantitatively reviewed based on the experimental data.The results show that OM pores are poorly developed in the immature stage due to weak hydrocarbon generation,although micro-fractures are occasionally found at the edges of OM particles.In the low maturity stage,OM pores are partially developed due to liquid hydrocarbon generation,with liquid hydrocarbons also filling some OM pores.The contribution of total organic carbon content(TOC)to adsorption extent is not significant in these two stages.From high to high-over maturity stages,massive gaseous hydrocarbons are generated,significantly improving the surface porosity of OM.Clear positive linear correlations are observed between TOC and adsorption amount.However,the development of OM pores significantly declines when thermal maturity(R_(o))exceeds 3.5%due to excessive aromatization.The accuracy of research on the evolution of pore structure and adsorption capacity is limited by several factors:(ⅰ)errors caused by sample specification,calculation processes,parameter settings,and kerogen models in isothermal adsorption experiments and molecular simulations;(ⅱ)difficulty in achieving control variables due to the strong heterogeneity of natural maturation shale samples;and(ⅲ)the need to enhance compatibility between thermal simulation experiments and natural thermal evolution.Therefore,isothermal adsorption experiments on bulk shale and molecular simulations of intact shale model are necessary,taking into account the dynamic temperature and pressure of in-situ reservoirs.Moreover,shale samples with varying maturity,influenced by their distance from the paleo-thermal source,may provide significant verification for thermal simulation experiments.展开更多
Time-reversal symmetry(TRS)breaking induced dissipationless topological phonon edge modes provide an unprecedented way to manipulate phonon transport.However,the effect of TRS breaking on the transport properties of b...Time-reversal symmetry(TRS)breaking induced dissipationless topological phonon edge modes provide an unprecedented way to manipulate phonon transport.However,the effect of TRS breaking on the transport properties of bulk phonon modes is still unclear.In this work,we assess the effect of local TRS-breaking domains on the transport properties of bulk phonon modes in a two-dimensional(2D)hexagonal phononic lattice model.The results show that bulk phonon modes can be strongly scattered by local TRS breaking owing to the shift of the local phonon band gap,which results in significant suppression of phonon transmission.Moreover,we show that the aperiodic distribution of local TRS-breaking domains can induce phonon Anderson localization,and the localization length can be effectively tuned by the strength of TRS breaking.Our study suggests that TRS breaking can not only be used to construct dissipationless topological phonon edge states,but also be used to block the transmission of bulk phonon modes by carefully controlling the size and distribution of TRS-breaking domains.Such results provide a highly alternative way for manipulating energy flux at the nanoscale.展开更多
In this study,AZ31 Mg alloy sheets were processed by a severe plastic deformation(SPD)technique called forging-bending repeated deformation(FBRD).The effect on the microstructure and microhardness of AZ31 Mg alloy thr...In this study,AZ31 Mg alloy sheets were processed by a severe plastic deformation(SPD)technique called forging-bending repeated deformation(FBRD).The effect on the microstructure and microhardness of AZ31 Mg alloy through FBRD was investigated with increasing temperature treatment and a 90°cross route.The results reveal that the effective strain increases with the number of passes.The flow uniformity is effectively enhanced due to alterations in shear deformation direction.After four passes of deformation,the average grain size is refined by 79.3%compared to the initial specimen.The grain refinement mechanism predominantly originates from the synergistic effects of discontinuous dynamic recrystallization(DDRX),continuous dynamic recrystallization(CDRX),and twinning-induced recrystallization(TDRX).The formation of{1012}extension twins(ET)significantly contributes to coarse grain subdivision and plastic deformation coordinated.Furthermore,pyramidal<c+a>slip activation effectively enhances the plasticity of Mg alloys.By post four-pass processing,the alloy exhibits a microhardness of 81.9HV,primarily governed by fine grain strengthening and dislocation strengthening mechanisms.展开更多
Gob-side entry retaining(GER)is widely applied in China.Nevertheless,the stability mechanism of the GER with coal pilla r-backfill body(CPBB)under dynamic overburden load remains unexplored.A voussoir beam structure(V...Gob-side entry retaining(GER)is widely applied in China.Nevertheless,the stability mechanism of the GER with coal pilla r-backfill body(CPBB)under dynamic overburden load remains unexplored.A voussoir beam structure(VBS)model is established to analyze roof structure stability during panel advancement,introducing a VBS stability criterion.Reducing block B length l and immediate roof damage variable D,and increasing coal pillar widthχ_(c).lowers the GER structure instability risk.Reducing l and the GER width w leads to a CPBB system stability upswing.A UDEC model was established to systematically reveal how the l,backfill body width x_(b),and strength affect the stability and coupling performance of the CPPB system by monitoring the crack damage D_(C).Simulation results indicate that at l=14 m,χ_(b)=2.0 m,watercement ratio 1.5:1,the coal pillar and backfill body have similar D_(C)but maintain stability,resulting in CPPB system coupling degree K,better.A novel GER method supported by the CPBB was implemented on-site.Monitoring results indicated that the coal pillar peak stresses were 19.17 MPa(ahead),16.14 MPa(behind),and the backfill body peak stress was 12.27 MPa(maximum).The floor heave was380 mm,with a 103 mm backfill body rib.展开更多
In this paper,the multi cross-rolling and cryogenic treatment were adopted to process the AZ31 Mg alloy to study the influence of passes and cryogenic treatment on cross-rolled AZ31 Mg alloy.The tensile properties and...In this paper,the multi cross-rolling and cryogenic treatment were adopted to process the AZ31 Mg alloy to study the influence of passes and cryogenic treatment on cross-rolled AZ31 Mg alloy.The tensile properties and hardness were tested.The microstructure was characterized using electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and scanning electron microscopy(SEM)in order to elucidate the influencing mechanism.The results indicate that the treatment method can significantly improve the mechanical properties of AZ31 Mg alloy.The 3-pass sample processed by cryogenic treatment shows the highest strength(351 MPa)and has the highest hardness(76.1HV)and best hardness uniformity(standard deviation=0.9HV).The 2-pass sample has the highest ductility among all the samples but poor hardness evenness.The strengthening mechanism of 3-pass sample can be attributed to the fine grains,bimodal structure,high dislocation density,and precipitation strengthening.Due to repeated heat preservation of 4-pass and 5-pass,their comprehensive performances decrease.展开更多
The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concr...The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.展开更多
基金financially supported by the Key Research and Development Project of Hunan Province in China(No.2023GK2028)the Major Basic Research Projects in Hunan Province(No.2024JC0005)the National Natural Science Foundation of China Regional Joint Fund Key Program(No.U24A20302)
文摘Zinc-based batteries(ZBBs)have garnered significant attention in the field of energy storage and conversion owing to their exceptional advantages,including high energy density,intrinsic environmental benignity,low material cost,as well as enhanced safety characteristics.Nevertheless,several critical challenges persist,predominantly the propensity for dendrite growth,inherent kinetic limitations,deleterious electrode side reactions,and perplexing shuttle effects,which collectively impede the practical implementation and commercial viability of ZBBs.In this context,fibers fabricated via electrospinning technology exhibit remarkable advantages in terms of enhanced specific surface area,improved electrical conductivity,and superior mechanical integrity,while also affording optimized pore structures.These unique features render electrospinning fibers particularly promising for addressing the key issues that limit ZBBs performance,including energy density,charge/discharge rate capabilities,and cycling stability.So,it is very necessary to summarize electrospinning technology application in ZBBs.This paper firstly analyzes the fundamental mechanisms and inherent challenges of ZBBs including zincion,zinc-air,and zinc-halide batteries.Subsequently,the application of electrospinning fiber structures in anodes,cathodes,separators,and electrolytes optimization for ZBBs is summarized.Finally,the prospect of electrospinning technology in ZBBs is envisioned,and existing challenges are presented for its further application.
基金supported by the National Natural Science Foundation of China(Grant Nos.52375420,52322510)Natural Science Foundation of Heilongjiang Province of China(Grant No.YQ2023E014)+6 种基金National Key Research and Development Program of China(Grant No.2021YFB3400403)Shenzhen Science and Technology Program(Grant No.GNCWSSJH20240032)Self-Planned Task(Grant No.SKLRS202214B)of State Key Laboratory of Robotics and System(HIT),China Postdoctoral Science Foundation(Grant No.2022T150163)Young Elite Scientists Sponsorship Program by CAST(Grant No.YESS20220463)Open Fund of Key Laboratory of Microsystems and Microstructures Manufacturing(HIT)(Grant No.2022KM004)Open Foundation of Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material(Grant No.E22445)Fundamental Research Funds for the Central Universities(Grant Nos.HIT.OCEF.2022024,FRFCU5710051122)。
文摘Silicon carbide(SiC)ceramics are extensively utilized in aerospace,national defense,and petrochemical industries due to their superior physical and chemical properties.The processing of bulk SiC ceramics necessitates precise and efficient grinding techniques to produce components with satisfactory functionality.However,the inherent high hardness and brittleness of SiC ceramics present significant challenges during grinding,leading to severe brittle fracture and tool wear that compromise both surface integrity and production efficiency.Although ductile-regime grinding of SiC ceramics can be achieved by enhancing machine tool accuracy and stiffness while optimizing wheel performance alongside appropriate selection of process parameters,a comprehensive summary of the mechanisms underlying damage evolution during grinding is lacking,and a mature grinding process for SiC ceramics has yet to be developed.To bridge this gap,the sintering technologies,mechanical properties,and microstructures of SiC ceramics were briefly covered.The grinding-induced damage mechanism and low-damage grinding technologies of SiC ceramics were summarized.The fundamental science underlying the ductile deformation and removal mechanisms of brittle solids was emphasized.Additionally,attention was directed towards the critical role of hybrid energy field grinding in minimizing brittle damages and promoting removal efficiency.This review not only elucidates the intrinsic interactions between the work material and abrasives,but also offers valuable insights for optimizing the grinding processes of brittle solids.
基金supported by the National Key Research and Development Program of China(Nos.2023YFC2809304 and 2022YFC2805904).
文摘Obtaining high-quality 10000-meter-deep seafloor sediment samples is the prerequisite and foundation for conducting deep-sea geological and environmental scientific research.The bottom structure of the deep seafloor is complex,and the physical and mechanical properties and disturbance resistance of sediments of different lithologies vary greatly,so the sediment sampler inevitably disturbs the sediments during the sampling process and affects the quality of the sediment samples.A new type of deep-sea sediment pressure retaining sampler is introduced,the force state and elastic–plastic state of the sampler destroying sediments are analyzed,the radial disturbance model of sediment coring based on the spherical cavity expansion theory is established,and the radius of sediments undergoing plastic deformation around the spherical holes is used as an index for evaluating the radial disturbance of sediments.The distribution of stress and strain fields in the sediments during the expansion of the spherical cavity and the influencing factors of the radius of the radially disturbed region(plastic region)are analyzed using an arithmetic example,and the influence law is analyzed.A sediment disturbance experimental platform was built indoors to simulate the sediment coring process.The radial stress field and pore water pressure of the sediment during the coring process were monitored by sensors arranged inside the sediment,and the results of indoor tests verified the correctness of the perturbation theory model.The sampler was carried aboard the deep-sea manned submersible FENDOUZHE and conducted on-site tests at depths of 9298.4 and 9142.8 m in the Kuril-Kamchatka Trench.Pressure-preserved sediment samples were retrieved,with preservation rates of 94.21%and 92.02%,respectively,which are much higher than the current technical indicator of 80%of pressure-holding ratio for deep-sea sediments.The retrieved sediments have obvious stratification characteristics and little disturbance.
基金supported by the Tianchi Talent-Young Doctor Program of the Xinjiang Uygur Autonomous Region,the Innovation Training Program for Undergraduates at the Autonomous Region Level in 2024(Grant No.S202410755009)the Innovation Training Program for Undergraduates at the University Level in 2024(Grant No.XJU-SRT-24008)+3 种基金the National Innovation Training Program for College Students in 2024(Grant No.202410755009)the National Natural Science Foundation of China(Grant No.42401065)the Basic and Applied Basic Research Program of Guangdong Province,China(Grant No.2023A1515011273)the Research Projects of the Department of Education of Guangdong Province(Grant No.2023KTSCX315).
文摘Aboveground biomass(AGB)and belowground biomass(BGB)are key components of carbon storage,yet their responses to future climate changes remain poorly understood,particularly in China.Understanding these dynamics is essential for global carbon cycle modeling and ecosystem management.This study integrates field observations,machine learning,and multi-source remote sensing data to reconstruct the distributions of AGB and BGB in China from 2000 to 2020.Then CMIP6 was used to predict the distribution of China under three SSP scenarios(SSP1-1.9,SSP2-4.5,SSP5-8.5)from 2020 to 2100 to fill the existing knowledge gap.The predictive accuracy for AGB(R^(2)=0.85)was significantly higher than for BGB(R^(2)=0.48),likely due to the greater complexity of modeling belowground dynamics.NDVI(Normalized Difference Vegetation Index)and soil organic carbon density(SOC)were identified as the primary drivers of AGB and BGB changes.During 2000-2020,AGB in China remained stable at approximately 10.69 Pg C,while BGB was around 5.06 Pg C.Forest ecosystems contributed 88.52% of AGB and 43.83% of BGB.AGB showed a relatively slow annual increase,while BGB demonstrated a significant annual growth rate of approximately 37 Tg C yr^(−1).Under the low-emission scenario,both AGB and BGB show fluctuations and steady growth,particularly in South China and the northwestern part of Northeast China.Under the moderate-emission scenario,AGB and BGB show significant declines and increases,respectively.In the high-emission scenario,both AGB and BGB decline significantly,particularly in the southwestern and central regions.These results provide valuable insights into ecosystem carbon dynamics under climate change,emphasizing the relatively low responsiveness of AGB and BGB to climatic variability,and offering guidance for sustainable land use and management strategies.
基金Project(42202318)supported by the National Natural Science Foundation of ChinaProject(252300421199)supported by the Natural Science Foundation of Henan Province,ChinaProject(2024JJ6219)supported by the Hunan Provincial Natural Science Foundation of China。
文摘The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique nature of this soil type.In this study,a series of unconfined compression tests were carried out on unsaturated CWG soil in an underground engineering site,and the effects of varying the environmental variables on the main undrained mechanical properties were analyzed.Based on the experimental results,a novel constitutive model was then established using the damage mechanics theory and the undetermined coefficient method.The results demonstrate that the curves of remolded CWG specimens with different moisture contents and dry densities exhibited diverse characteristics,including brittleness,significant softening,and ductility.As a typical indicator,the unconfined compression strength of soil specimens initially increased with an increase in moisture content and then decreased.Meanwhile,an optimal moisture content of approximately 10.5%could be observed,while a critical moisture content value of 13.0%was identified,beyond which the strength of the specimen decreases sharply.Moreover,the deformation and fracture of CWG specimens were predominantly caused by shear failure,and the ultimate failure modes were primarily influenced by moisture content rather than dry density.Furthermore,by comparing several similar models and the experimental data,the proposed model could accurately replicate the undrained mechanical characteristics of unsaturated CWG soil,and quantitatively describe the key mechanical indexes.These findings offer a valuable reference point for understanding the underlying mechanisms,anticipating potential risks,and implementing effective control measures in similar underground engineering projects.
文摘In this paper, introducing new remote sensing and geographic information technology to solve the problem of data collection and analysis, this makes the study of ecological risk assessment very quick and accurate. Taking the Shan Xin mining area of the tin mine in Lengshuijiang of Hunan Province as the research object, using the remote sensing image data of three periods in 2005, 2010 and 2015, the remote sensing image is classified carefully and the landscape classification map of the mining area is obtained. The ecological risk index is introduced and the ecological risk values are sampled and interpolated on the ArcGIS platform. The ecological risk spatial distribution map based on the landscape pattern index was obtained. The ecological risk was divided into 5 levels by using the Jenks natural classification method, and each ecological risk grade area was counted. The research results show that: from year 2005 to year 2010, landscape ecological risk trend of the mining area is growing up;the trend rising area of landscape ecological risk is mainly in the southwest and northeast of the Shan Xin mining field;the area of higher and high ecological risk is increasing year by year;and the trend of dispersed development in space is obvious;the development trend of ecological risk in the mining area is rapidly increasing;in 2010 - 2015, the higher and high ecological risk area decrease slightly with the increasing of area of grassland and residential low vulnerability of landscape types;the ecological risk area showed a slow decreasing trend. The research results provide an objective reference for decision making of ecological environment governance.
基金湖南省教育厅基金优秀青年项目(No.22B0482)湖南科技大学博士启动基金(No.E51992 and E51993)资助。
文摘The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.
基金provided by the National Natural Science Foundation of China (No. 50674046)the Open Foundation of Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines of China (No. 200803)
文摘Based on engineering practices of Wuyang Coal Mine, we carried out X-ray diffract researches on No. 3 coal; and the rocks of its roof and floor by XRD meter, and simulated the interactive effect of the surrounding rock deformation by FLAC2DS.0 numerical simulation software under the condition of different tunneling method of multimine roadway in parallel. The internal structures of the surrounding rocks of 76 belt roadway were monitored by borehole observation instruments： and then, we analyzed the reason of fhilure and deformation of surrounding rocks of several rise entry, and proposed the technical mea- sures for controlling interactive effect of several rise entry surrounding rock deformation at last. For the thickness seam rise roadway, two conclusions were drawn： one is that the co-deformation among roadway groups mainly reflect on that both shear failure and deformation in coal pillar among roadways have decreased the width of pillar core region and clamping action of coal pillar to roof strata, increased the actual span of roof strata, intensified the flexural failure of roof strata and prized the bed separation of roof deep rock strata. The other conclusion is that the factors controlling the interactive deformation among roadways is obvious when appropriate re-adjustment in construction sequence of the tunneling of multimine parallel roadways because the construction sequence among roadways also has great effects on deformation of the surrounding rock in roadway.
基金the financial support of the National Natural Science Foundation of China(No.51971191)Scientific Research Project of Education Department of Hunan Province(Nos.22B0178,22C0075)+1 种基金Hunan Provincial Innovation Foundation for Postgraduate(No.CX20220558)the National Scholarship Foundation(No.202008430013)。
文摘The sulfate-reducing bacteria(SRB)corrosion of H70 brass,H80 brass and T2 copper was systematically studied using microstructure characterizations and electrochemical measurements.The results showed that H70 brass,H80 brass and T2 copper exhibited good corrosion resistance in the sterile environment,and the corrosion products were mainly metal oxides,such as Cu_(2)O,CuO and ZnO.The SRB metabolism sharply accelerated the corrosion process of three types of copper alloys,especially the T2 copper.In the inoculated environment,an additional mixture of Cu_(2)S,ZnS and CuSO_(4)existed in the corrosion products.Pitting corrosion was the main corrosion style for the H70 brass and H80 brass,while general corrosion and pitting corrosion simultaneously dominated the corrosion process of the T2 copper in this environment.The results provide a new insight to the microbiological corrosion of copper alloys.
文摘Memristor chaotic research has become a hotspot in the academic world.However,there is little exploration combining memristor and stochastic resonance,and the correlation research between chaos and stochastic resonance is still in the preliminary stage.In this paper,we focus on the stochastic resonance induced by memristor chaos,which enhances the dynamics of chaotic systems through the introduction of memristor and induces memristor stochastic resonance under certain conditions.First,the memristor chaos model is constructed,and the memristor stochastic resonance model is constructed by adjusting the parameters of the memristor chaos model.Second,the combination of dynamic analysis and experimental verification is used to analyze the memristor stochastic resonance and to investigate the trend of the output signal of the system under different amplitudes of the input signal.Finally,the practicality and reliability of the constructed model are further verified through the design and testing of the analog circuit,which provides strong support for the practical application of the memristor chaos-induced stochastic resonance model.
基金Supported by National Key Research and Development Program of China(Grant Nos.2023YFC2809304,2022YFC2805904)National Natural Science Foundation of China(Grant No.52275106)Special Project for the Construction of Innovative City in Xiangtan of China(Grant No.ZX-ZD20221005).
文摘To accurately acquire deep-sea live biological samples,a hydraulic suction macro-biological pressure-retaining sampler(HSMPS)was designed to achieve active capture of seafloor biological by a suction pump.The complex flow fields of deep-sea biologicals at three different locations were simulated.The deep-sea biologicals cause the flow field pressure and velocity to rise at different locations of the sampler,and the magnitude of the rise varies at different locations.The internal flow properties of the sampler were analyzed for different pumping flow rates the sampler.When the flow rate of the sampler pump was greater than 14 m3/h,the velocity of the inlet of the inflow area was greater than the limiting velocity of the deep-sea biologicals.The pumping test of deep-sea biologicals pumping sampler was carried out in the laboratory,and the test results were basically consistent with the simulation analysis.In order to balance the deep-sea biologicals damage and escape rate,the pumping flow of the sampler should be controlled between 14 and 16 m3/h.The test results provide a theoretical basis for the design of deep-sea biologicals sampling equipment.
基金supported in part by the National Natural Science Foundation of China(Grant No.12432001)Natural Science Foundation of Hunan Province(Grant Nos.2023JJ60527,2023JJ30152,and 2023JJ30259)the Natural Science Foundation of Changsha(KQ2202133).
文摘This study investigates the nonlinear resonance responses of suspended cables subjected to multi-frequency excitations and time-delayed feedback.Two specific combinations and simultaneous resonances are selected for detailed examination.Initially,utilizing Hamilton’s variational principle,a nonlinear vibration control model of suspended cables under multi-frequency excitations and longitudinal time-delayed velocity feedback is developed,and the Galerkin method is employed to obtain the discrete model.Subsequently,focusing solely on single-mode discretization,analytical solutions for the two simultaneous resonances are derived using the method of multiple scales.The frequency response equations are derived,and the stability analysis is presented for two simultaneous resonance cases.The results demonstrate that suspended cables exhibit complex nonlinearity under multi-frequency excitations.Multiple solutions under multi-frequency excitation can be distinguished through the frequency–response and the detuning-phase curves.By adjusting the control gain and time delay,the resonance range,response amplitude,and phase of suspended cables can be modified.
基金supported by the Science and Technology Talent Promotion Project(2023TJ-Z09)Innovation Program(2023RC1077,2023JJ40279)of Hunan Province,China.
文摘Brassica clubroot caused by Plasmodiophora brassicae has been identified as a severe soil-borne disease that poses a significant threat to plants root systems.The disease results in the formation of tumorous enlargements in the roots,leading to wilting and eventual plant death.Consequently,crop yield is drastically reduced,causing substantial economic losses in agriculture.The current study aims to provide a comprehensive overview of recent research process on Brassica clubroot,focusing on the biological characteristics,physiological race identification,and pathogenic mechanism of P.brassicae.Furthermore,it covers the latest advancements in the comprehensive prevention and clubroot control.The insights gained from this study are expected to contribute to the future research on clubroot and the development of resistance breeding strategies.
基金supported by the National Natural Science Foundation of China(Grant No.52372260)the Science Fund for Distinguished Young Scholars of Hunan Province(Grant Nos.2024JJ2048 and 2021JJ10036)+1 种基金the Science and Technology Innovation Program of Hunan Province(Grant No.2022RC1197)the Scientific Research Fund of Hunan Provincial Education Department(Grant No.22B0512)。
文摘By combining neuroevolution potential(NEP)with phonon Boltzmann transport theory,we systematically investigate the thermal transport properties of three two-dimensional(2D)narrow bandgap semiconductors:Ca_(3)N_(2),Ba_(3)P_(2),and Ba_(3)As_(2).The room-temperature lattice thermal conductivities(κ_(L))of Ca_(3)N_(2),Ba_(3)P_(2),and Ba_(3)As_(2)considering only three-phonon scattering are 6.60 W/m K,11.90 W/m K,and 8.88 W/m K,respectively.When taking into account the higherorder phonon(four-phonon)scattering processes,theκL of these three materials decrease to 6.12 W/m K,9.73 W/m K and6.77 W/m K,respectively.Among these systems,Ba_(3)As_(2)undergoes the most pronounced suppression with a reduction of 23.8%.This is mainly due to the greater scattering phase space which enhances the four-phonon scattering.Meanwhile,it is revealed that unlike the traditional evaluation using the P_(4)/P_(3)ratio as an indicator of the strength of four-phonon interactions,the thermal conductivity of Ba_(3)P_(2)exhibits weaker four-phonon suppression behavior compared to Ba_(3)As_(2),despite hosting a higher P_(4)/P_(3)ratio.That is to say,the strength of four-phonon scattering cannot be evaluated solely by the ratio of P_(4)/P_(3).These results presented in this work shed light on the thermal transport properties of such new 2D semiconductors with narrow bandgaps.
基金the supports of the Na-tional Natural Science Foundation of China(No.U19B2007,42072202)the China Postdoctoral Science Foundation(No.2025MD774057)。
文摘Organic matter(OM)is the primary gas occurrence carrier in shale reservoirs due to their abundant nanopores.To reveal the OM pore structure,adsorption capacity and evolution during thermal maturation,this study collected data from samples spanning the entire evolution stage,from immature to over-mature.Scanning Electron Microscope(SEM)observation and low temperature gases adsorption experiments were used to qualitatively-semi-quantitatively and quantitatively analyze OM pore structure evolution,and CH_(4) isothermal adsorption experiments were used to reveal the adsorption capacity evolution.Then,the influence and mechanism of matu rity and hydrocarbon generation on pore development and adsorption capacity were quantitatively reviewed based on the experimental data.The results show that OM pores are poorly developed in the immature stage due to weak hydrocarbon generation,although micro-fractures are occasionally found at the edges of OM particles.In the low maturity stage,OM pores are partially developed due to liquid hydrocarbon generation,with liquid hydrocarbons also filling some OM pores.The contribution of total organic carbon content(TOC)to adsorption extent is not significant in these two stages.From high to high-over maturity stages,massive gaseous hydrocarbons are generated,significantly improving the surface porosity of OM.Clear positive linear correlations are observed between TOC and adsorption amount.However,the development of OM pores significantly declines when thermal maturity(R_(o))exceeds 3.5%due to excessive aromatization.The accuracy of research on the evolution of pore structure and adsorption capacity is limited by several factors:(ⅰ)errors caused by sample specification,calculation processes,parameter settings,and kerogen models in isothermal adsorption experiments and molecular simulations;(ⅱ)difficulty in achieving control variables due to the strong heterogeneity of natural maturation shale samples;and(ⅲ)the need to enhance compatibility between thermal simulation experiments and natural thermal evolution.Therefore,isothermal adsorption experiments on bulk shale and molecular simulations of intact shale model are necessary,taking into account the dynamic temperature and pressure of in-situ reservoirs.Moreover,shale samples with varying maturity,influenced by their distance from the paleo-thermal source,may provide significant verification for thermal simulation experiments.
基金supported by the National Natural Science Foundation of China(Grant No.12404011)the Natural Science Foundation of Hunan Province(Grant No.2023JJ40273)the Scientific Research Foundation of Hunan Provincial Education Department(Grant No.23B0495).
文摘Time-reversal symmetry(TRS)breaking induced dissipationless topological phonon edge modes provide an unprecedented way to manipulate phonon transport.However,the effect of TRS breaking on the transport properties of bulk phonon modes is still unclear.In this work,we assess the effect of local TRS-breaking domains on the transport properties of bulk phonon modes in a two-dimensional(2D)hexagonal phononic lattice model.The results show that bulk phonon modes can be strongly scattered by local TRS breaking owing to the shift of the local phonon band gap,which results in significant suppression of phonon transmission.Moreover,we show that the aperiodic distribution of local TRS-breaking domains can induce phonon Anderson localization,and the localization length can be effectively tuned by the strength of TRS breaking.Our study suggests that TRS breaking can not only be used to construct dissipationless topological phonon edge states,but also be used to block the transmission of bulk phonon modes by carefully controlling the size and distribution of TRS-breaking domains.Such results provide a highly alternative way for manipulating energy flux at the nanoscale.
基金Project(52174362)supported by the National Natural Science Foundation of ChinaProject(2023JJ10020)supported by the Natural Science Foundation of Hunan Province,China+2 种基金Project(2024RC7002)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2024CY2-GJHX-71)supported by the Shaanxi Provincial Key R&D Program,ChinaProject supported by the Yancheng“Talent Plan of Yellow Sea Pearl”for Leading Talent Project,China。
文摘In this study,AZ31 Mg alloy sheets were processed by a severe plastic deformation(SPD)technique called forging-bending repeated deformation(FBRD).The effect on the microstructure and microhardness of AZ31 Mg alloy through FBRD was investigated with increasing temperature treatment and a 90°cross route.The results reveal that the effective strain increases with the number of passes.The flow uniformity is effectively enhanced due to alterations in shear deformation direction.After four passes of deformation,the average grain size is refined by 79.3%compared to the initial specimen.The grain refinement mechanism predominantly originates from the synergistic effects of discontinuous dynamic recrystallization(DDRX),continuous dynamic recrystallization(CDRX),and twinning-induced recrystallization(TDRX).The formation of{1012}extension twins(ET)significantly contributes to coarse grain subdivision and plastic deformation coordinated.Furthermore,pyramidal<c+a>slip activation effectively enhances the plasticity of Mg alloys.By post four-pass processing,the alloy exhibits a microhardness of 81.9HV,primarily governed by fine grain strengthening and dislocation strengthening mechanisms.
基金financial support provided by the National Natural Science Foundation of China(Nos.52574126and 52574144)the Xinjiang Uygur Autonomous Region Key R&D Project Task Special-Department and Department Linkage Project(No.2022B01051)+4 种基金the Major Project of Regional Joint Foundation of China(No.U21A20107)the Xinjiang Uygur Autonomous Region Tianchi Introduction Plan(No.2024XGYTCYC03)the Scientific Research Fund of Hunan Provincial Education Department(No.24A0359)the Urumqi City Hongshan Sci-Tech Innvoation Elite Talents Youth Top Talents Program(No.B241013004)the National Key Research and Development Program Young Scientists Project(No.2024YFC2910600)。
文摘Gob-side entry retaining(GER)is widely applied in China.Nevertheless,the stability mechanism of the GER with coal pilla r-backfill body(CPBB)under dynamic overburden load remains unexplored.A voussoir beam structure(VBS)model is established to analyze roof structure stability during panel advancement,introducing a VBS stability criterion.Reducing block B length l and immediate roof damage variable D,and increasing coal pillar widthχ_(c).lowers the GER structure instability risk.Reducing l and the GER width w leads to a CPBB system stability upswing.A UDEC model was established to systematically reveal how the l,backfill body width x_(b),and strength affect the stability and coupling performance of the CPPB system by monitoring the crack damage D_(C).Simulation results indicate that at l=14 m,χ_(b)=2.0 m,watercement ratio 1.5:1,the coal pillar and backfill body have similar D_(C)but maintain stability,resulting in CPPB system coupling degree K,better.A novel GER method supported by the CPBB was implemented on-site.Monitoring results indicated that the coal pillar peak stresses were 19.17 MPa(ahead),16.14 MPa(behind),and the backfill body peak stress was 12.27 MPa(maximum).The floor heave was380 mm,with a 103 mm backfill body rib.
基金Project(52174362)supported by the National Natural Science Foundation of ChinaProject(2023JJ10020)supported by the Natural Science Foundation of Hunan Province,China+3 种基金Project(2024RC7002)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2024CY2-GJHX-71)supported by the Shaanxi Provincial Key R&D ProgramProject supported by the Yancheng“Talent Plan of Yellow Sea Pearl”for Leading Talent Project,ChinaProject(2019GK1012)supported by the Hunan Innovative Province Construction Special Program,China。
文摘In this paper,the multi cross-rolling and cryogenic treatment were adopted to process the AZ31 Mg alloy to study the influence of passes and cryogenic treatment on cross-rolled AZ31 Mg alloy.The tensile properties and hardness were tested.The microstructure was characterized using electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and scanning electron microscopy(SEM)in order to elucidate the influencing mechanism.The results indicate that the treatment method can significantly improve the mechanical properties of AZ31 Mg alloy.The 3-pass sample processed by cryogenic treatment shows the highest strength(351 MPa)and has the highest hardness(76.1HV)and best hardness uniformity(standard deviation=0.9HV).The 2-pass sample has the highest ductility among all the samples but poor hardness evenness.The strengthening mechanism of 3-pass sample can be attributed to the fine grains,bimodal structure,high dislocation density,and precipitation strengthening.Due to repeated heat preservation of 4-pass and 5-pass,their comprehensive performances decrease.
基金financial support by the National Natural Science Foundation of China(52174101&52408310)Guangdong Basic and Applied Basic Research Foundation(2023A1515011634&2024A1515012528)Guangdong Provincial Department of Science and Technology(2021ZT09G087)for the research.
文摘The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.
