Tellurene,a chiral chain semiconductor with a narrow bandgap and exceptional strain sensitivity,emerges as a pivotal material for tailoring electronic and optoelectronic properties via strain engineering.This study el...Tellurene,a chiral chain semiconductor with a narrow bandgap and exceptional strain sensitivity,emerges as a pivotal material for tailoring electronic and optoelectronic properties via strain engineering.This study elucidates the fundamental mechanisms of ultrafast laser shock imprinting(LSI)in two-dimensional tellurium(Te),establishing a direct relationship between strain field orientation,mold topology,and anisotropic structural evolution.This is the first demonstration of ultrafast LSI on chiral chain Te unveiling orientation-sensitive dislocation networks.By applying controlled strain fields parallel or transverse to Te’s helical chains,we uncover two distinct deformation regimes.Strain aligned parallel to the chain’s direction induces gliding and rotation governed by weak interchain interactions,preserving covalent intrachain bonds and vibrational modes.In contrast,transverse strain drives shear-mediated multimodal deformations—tensile stretching,compression,and bending—resulting in significant lattice distortions and electronic property modulation.We discovered the critical role of mold topology on deformation:sharp-edged gratings generate localized shear forces surpassing those from homogeneous strain fields via smooth CD molds,triggering dislocation tangle formation,lattice reorientation,and inhomogeneous plastic deformation.Asymmetrical strain configurations enable localized structural transformations while retaining single-crystal integrity in adjacent regions—a balance essential for functional device integration.These insights position LSI as a precision tool for nanoscale strain engineering,capable of sculpting 2D material morphologies without compromising crystallinity.By bridging ultrafast mechanics with chiral chain material science,this work advances the design of strain-tunable devices for next-generation electronics and optoelectronics,while establishing a universal framework for manipulating anisotropic 2D systems under extreme strain rates.This work discovered crystallographic orientation-dependent deformation mechanisms in 2D Te,linking parallel strain to chain gliding and transverse strain to shear-driven multimodal distortion.It demonstrates mold geometry as a critical lever for strain localization and dislocation dynamics,with sharp-edged gratings enabling unprecedented control over lattice reorientation.Crucially,the identification of strain field conditions that reconcile severe plastic deformation with single-crystal retention offers a pathway to functional nanostructure fabrication,redefining LSI’s potential in ultrafast strain engineering of chiral chain materials.展开更多
This paper investigates process parameter effects on microstructure and mechanical properties of the tubes processed via recently developed friction assisted tube straining(FATS)method.For this purpose,design of exper...This paper investigates process parameter effects on microstructure and mechanical properties of the tubes processed via recently developed friction assisted tube straining(FATS)method.For this purpose,design of experiment was used to arrange finite element analyses and experimental tests.Numerical and experimental tests were executed by changing rotary speed,feed rate and die angle.Taguchi design results show that increasing feed rate and decreasing rotary speed enhance Zener-Hollomon(Z)parameter and decrease average grain size,while die angle has no considerable effect.Increasing Z value reduces grain size and enhances flow stress of the processed samples,while the experiment with the highest Z value refines initial microstructure from 40 to 8μm and increases flow stress by 5 times.展开更多
The hot deformation characteristics of 1.4462 duplex stainless steel （DSS） were analyzed by considering strain partitioning between austenite and ferrite constituents. The individual behavior of ferrite and austenit...The hot deformation characteristics of 1.4462 duplex stainless steel （DSS） were analyzed by considering strain partitioning between austenite and ferrite constituents. The individual behavior of ferrite and austenite in microstructure was studied in an iso-stress condition. Hot compression tests were performed at temperatures of 800-1100~C and strain rates of 0.001-1 s-1. The flow stress was modeled by a hyperbolic sine constitutive equation, the corresponding constants and apparent activation energies were determined for the studied alloys. The constitutive equation and law of mixture were used to measure the contribution factor of each phase at any given strain. It is found that the contribution factor of ferrite exponentially declines as the Zener-HoUomon parameter （Z） increases. On the contrary, the austenite contribution polynomially increases with the increase of Z. At low Z values below 2.6. x 1015 （lnZ---35.5）, a negative contribution factor is determined for austenite that is attributed to dynamic recrystallization. At high Z values, the contribution factor of austenite is about two orders of magnitude greater than that of ferrite, and therefore, austenite can accommodate more strain. Microstructural characterization via electron back-scattered diffraction （EBSD） confirms the mechanical results and shows that austenite recrystallization is possible only at high temperature and low strain rate.展开更多
The dynamic strain aging(DSA) behavior was investigated in GH4169 alloy during tensile deforming with electric-pulse current(EPC) at 750 ℃.The results show that DSA is restrained in the alloy when deformed with 40 Hz...The dynamic strain aging(DSA) behavior was investigated in GH4169 alloy during tensile deforming with electric-pulse current(EPC) at 750 ℃.The results show that DSA is restrained in the alloy when deformed with 40 Hz-EPC.The size ofγ " phase inner grains increases obviously and δ phase is facilitated to precipitate on grain boundary in the alloy applied with EPC,due to the promotion effect of EPC on the diffusion and segregation of atoms.Transmission electron microscopy(TEM)results indicate that dislocations can cut through small γ" precipitate with the size of less than 10 nm,while dislocations can only bypass dislocations when γ " precipitate grow up over 20 nm.The growth of precipitates consumes large amounts of atoms as well as the velocity of dislocation increase,which makes dislocations difficult to be pinned.Therefore,when γ" precipitates grow up to a large size more than the critical size of dislocation pinning,DSA is significantly restrained in the alloy after necking deformed with EPC.展开更多
The mechanisms responsible for deformation behavior in Nb/NiTi composite during pre-straining were investigated systematically using in-situ synchrotron X-ray diffraction, transmission electron microscopy and tensile ...The mechanisms responsible for deformation behavior in Nb/NiTi composite during pre-straining were investigated systematically using in-situ synchrotron X-ray diffraction, transmission electron microscopy and tensile test. It is shown that upon loading, the composite experiences elastic elongation and slight plastic deformation of B19′,B2 and β-Nb phases, together with the forward stress-induced martensitic(SIM) transformation from B2 to B19′. Upon unloading, the deformation mechanisms of the composite mainly involve elastic recovery of B19′, B2 and β-Nb phases,compression deformation of β-Nb phase and incomplete B19′→B2 reverse SIM transformation. In the tensile loading-unloading procedure, besides the inherent elastic deformation and SIM transformation, the(001) compound twins in B19′ martensite can also be conducive to the elastic deformation occurring in B19′-phase of the composite.Therefore, this composite can exhibit a large recoverable strain after unloading owing to the elastic deformation, and the partially reversible and consecutive SIM transformation together with the(001) compound twins.展开更多
Ultrasonic-Assisted Grinding(UAG)is a novel manufacturing technology that shows promising promise for use in processing Ceramic Matrix Composites(CMCs).Nevertheless,analyzing the material removal process of CMCs with ...Ultrasonic-Assisted Grinding(UAG)is a novel manufacturing technology that shows promising promise for use in processing Ceramic Matrix Composites(CMCs).Nevertheless,analyzing the material removal process of CMCs with multidirectional structure during UAG is challenging,impeding the progress and improvement of the UAG process.This work examined the impact of ultrasonic vibration on the dynamic mechanical characteristics during processing.Additionally,we experimentally elucidated the material removal mechanism of CMCs during the scratching process under the influence of vertical vibration.The results indicate that the introduction of ultrasonic vibration causes a strain rate effect,resulting in a modification of the material removal mechanism,subsequently impacting the processing quality.Ultrasonic vibration increases the dynamic strength and brittleness of the fibers in CMCs,leading to more cracks at fracture,which changes from the original bending fracture to shear fracture.In addition,ultrasonic vibration can effectively inhibit the impact of scratching depth and anisotropy on the removal mechanism of CMCs,resulting in a more uniform surface of CMCs after processing.展开更多
Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabl...Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabling topological functionalities in the post-Moore era.Here we review recent progress on two-dimensional(2D)magnetism in LTMCs,emphasizing material taxonomy,intrinsic magnetic properties,and external-field controls.This review first presents a classification of LTMCs by crystal structure and chemistry—binary halides,chalcogenides,and ternary families(e.g.,MPX_(3),M_(m)X_(n)Te_(k),MnBi_(2)Te_(4))—followed by a summary of their coupling mechanisms,ordering temperatures,and dimensional effects.It then analyzes the modulation of exchange interactions,magnetic anisotropy,and topological states by electric-field gating,strain engineering,and ion intercalation,with representative experimental demonstrations.Notable advances include room-temperature ferromagnetic metals and semiconductors,observation of the quantum anomalous Hall effect(QAHE)in MnBi2Te4,and synergistic control of magnetic-topological states under multiple external stimuli.Persistent challenges involve the limited availability of intrinsic 2D magnetic semiconductors with high Curie temperatures(Tc),incomplete understanding of the microscopic couplings at interfaces and under quantum confinement,and device-level stability.We conclude by outlining opportunities that lie in the integration of multiscale characterization,first-principles theory,and cross-scale fabrication to precisely co-engineer magnetism,topology,and electronic structure,thereby advancing LTMCs toward spintronic and topological-quantum applications.展开更多
This study compared the acute effects of electrical energy transfer(TECAR) and transcutaneous electrical stimulation(TENS) on pain and flexibility after a hamstring injury. Young athletes received either a 20 min TECA...This study compared the acute effects of electrical energy transfer(TECAR) and transcutaneous electrical stimulation(TENS) on pain and flexibility after a hamstring injury. Young athletes received either a 20 min TECAR(n = 24) or TENS(n = 26) session within 5 days following a hamstring injury, while the control(CON, n = 25)group was instructed to rest. Visual analogue scale(VAS), functional Assessment Scale for Acute Hamstring Injuries(FASH), straight leg raise test(SLR), and sit-and-reach scores(STR) were obtained prior to, immediately,24, and 48 h after therapy. Group differences were detected after therapy in VAS and FASH scores(p < 0.05).Compared to pre-therapy measurements, VAS scores showed a greater decrease in the TECAR group(-38.75% to-63.33%) than in the TENS group(-16.67% to-25.00%) and both were greater than in the CON group(-2.81%to-9.81%)(p < 0.05). The TECAR group improved FASH scores(28.57%–48.21%) more than the TENS group(15.89%–27.79%) and both groups more than the CON group(0%–8.33%)(p < 0.05). The increase in SLR and STR was greater in the TECAR group(6.26%–13.96%) than in the TENS(1.72%–9.53%) and CON groups(0%–3.03%). These results suggest that in the acute phase of hamstring injury, the use of TECAR and, to a lesser extent, TENS may relieve pain symptoms and bring some improvements in flexibility more than instructing patients to rest.展开更多
Ionogel,a novel flexible electronic material,presents a plethora of applications.Despite its potential,the fabrication of multifunctional ionogel with high-performance suitable for diverse scenarios remains a signific...Ionogel,a novel flexible electronic material,presents a plethora of applications.Despite its potential,the fabrication of multifunctional ionogel with high-performance suitable for diverse scenarios remains a significant challenge.In this study,we prepare a multifunctional amphibious ionogel skin(AIGS)using a polymerizable ionic liquid(PIL)and a conductive ionic liquid(IL)in conjunction with titanium carbide(Ti_(3)C_(2)T_(x)-MXene).The resulting soft AIGS materials exhibit ductility,self-healing,and robust adhesion in mechanical properties due to non-covalent interactions,such as ion-dipole interactions and hydrogen bonding.They also demonstrate a wide sensing range(2%-400%),high sensing sensitivity(gauge factor(GF)up to 6.06),and stable sensing performance(good reliability and stability after strain)in electrical properties.The hydrophobic and dynamic viscoelastic network formed by extensive C-F bonds in the used polymer matrix,ensures the AIGS's suitability for amphibious environments.We find that AIGS has excellent triboelectric properties.Utilizing AIGS as a flexible electrode,a single-electrode triboelectric nanogenerator(SE-TENG)was constructed,achieving outstanding output performance(~300 V open-circuit voltage,172 nA short-circuit current,and 34 nC transferred charge).This device can power commercial portable electronic devices and identify different body movements.AIGS-based wearable strain sensors have also been shown to reliably detect human motion,including larger limb movements such as finger flexion and elbow flexion and extension,as well as subtle muscle movements such as frowning and swallowing.In addition,depending on the characteristics of the AIGS application in amphibious environments,the following functions can be realized simultaneously.AIGS in an aquatic environment combined with machine learning for intelligent recognition of breathing type,in an underwater environment combined with Morse code to convey simple information,and motion monitoring in an amphibious environment,demonstrates its potential feasibility in a variety of situations.展开更多
Single-crystal GaN epilayers were irradiated with heavy inert gas ions(2.3-MeV Ne^(8+),5.3-MeV Kr^(19+))to fluences ranging from 1.0×1.0^(11) to 1.0×1.0^(15)ions∕cm^(2).The strain-related damage accumulatio...Single-crystal GaN epilayers were irradiated with heavy inert gas ions(2.3-MeV Ne^(8+),5.3-MeV Kr^(19+))to fluences ranging from 1.0×1.0^(11) to 1.0×1.0^(15)ions∕cm^(2).The strain-related damage accumulation versus ion fluences was studied using highresolution X-ray diffraction(HRXRD)and ultraviolet–visible(UV–Vis)spectroscopy.The results showed that the damage accumulation was mainly dominated by nuclear energy loss.When the ion fluence was less than∼0.055 displacement per atom(dpa),the lattice expansions and lattice strains markedly increased linearly with increasing ion fluences,accompanied by a slow enhancement in the dislocation densities,distortion parameters,and Urbach energy for both ion irradiations.Above this fluence(∼0.055 dpa),the lattice strains presented a slight increase,whereas a remarkable increase was observed in the dislocation densities,distortion parameters,and Urbach energy with the ion fluences after both ion irradiations.∼0.055 dpa is the threshold ion fluence for defect evolution and lattice damage related to strain.The mechanisms underlying the damage accumulation are discussed in detail.展开更多
Background As probiotics,Bacillus strains may regulate some physiological functions in animals.This study aimed to evaluate whether dietary supplementation with a Bacillus-based probiotic could alleviate gut damage in...Background As probiotics,Bacillus strains may regulate some physiological functions in animals.This study aimed to evaluate whether dietary supplementation with a Bacillus-based probiotic could alleviate gut damage induced by rotavirus(RV)infection in piglets.Twenty-four piglets were randomly assigned into 2 groups fed with the basal diet(n=16)and the diet containing 10^(9) colony-forming unit Bacillus spores/kg(n=8).On d 8,8 piglets fed with the diet supplemented with Bacillus-based probiotic and 8 piglets fed with basal diet were orally infused with RV,while the residue piglets had oral gavage of sterile essential medium.The trial duration was 12 d.Results RV challenge induced diarrhea,significantly destroyed the morphology of jejunal mucosa(P<0.05),significantly increased RV-antibody and RV non-structural protein 4 of jejunal mucosa(P<0.05),significantly impaired antioxidant capacity(including malondialdehyde level,total antioxidant capacity and catalase activity),immunity(such as interleukin 2,interleukin 4 and secreted immunoglobulin A levels),mucins and the m RNA expression of tightjunction-related(such as Zonula occludens 1,occludin)and apoptotic-related(including B-cell lymphoma/leukaemia-2-associated X protein,B cell lymphoma/leukaemia-2,cysteinyl aspartate specific proteinases)genes of jejunal mucosa(P<0.05),and,to some extents,affected the bacteria community structure and abundance of ileal digesta in piglets.However,Bacillus-based probiotic administration could significantly attenuate the negative effects of RV infection on gut health of piglets(P<0.05).Conclusions These findings suggested that supplementing Bacillus-based probiotic in the diet could decrease diarrhea rate,and improve gut health in weaned piglets,which was associated with regulating intestinal antioxidant capacity,apoptosis,and microbiota.展开更多
Conductive cotton fabrics have emerged as promising platforms for advanced wearable applications,including strain sensing,electrical heating,and photothermal conversion.However,their widespread adoption is hindered by...Conductive cotton fabrics have emerged as promising platforms for advanced wearable applications,including strain sensing,electrical heating,and photothermal conversion.However,their widespread adoption is hindered by several critical limitations:dependence on petroleum-based materials,inherent hydrophilicity,and insufficient durability in practical environments.To overcome these challenges,an eco-friendly,mussel-inspired conductive coating system comprising tannic acid,cellulose nanofibers,and carbon nanotubes is developed.Through a facile dip-coating approach followed by in situ tannic acid polymerization-induced surface roughening and octadecylamine modification,a superhydrophobic conductive cotton fabric combining exceptional flexibility,breathability,and environmental stability is fabricated.The resulting superhydrophobic conductive cotton fabric demonstrates outstanding strain-sensing performance,featuring a rapid response time(127 ms)and reliable signal output over 4000 stretching cycles,capable of precisely detecting various human motions even underwater.Furthermore,the superhydrophobic conductive cotton fabric achieves impressive electrothermal(103.9℃at 15 V)and photothermal(104.2℃at 350 mW cm^(-2))conversion efficiencies with excellent temperature controllability.This multifunctional fabric presents a sustainable solution for next-generation wearable electronics and intelligent thermal management systems,addressing both environmental concerns and performance requirements for real-world applications.展开更多
Granular materials exhibit complex macroscopic mechanical behaviors closely related to their microscalemicrostructural features.Traditional macroscopic phenomenological elasto-plastic models,however,usually have compl...Granular materials exhibit complex macroscopic mechanical behaviors closely related to their microscalemicrostructural features.Traditional macroscopic phenomenological elasto-plastic models,however,usually have complex formulations and lack explicit relations to these microstructural features.To avoid these limitations,this study proposes a micromechanics-based softening hyperelastic model for granular materials,integrating softening hyperelasticity withmicrostructural insights to capture strain softening,critical state,and strain localization behaviors.The model has two key advantages:(1)a clear conceptualization,straightforward formulation,and ease of numerical implementation(via Abaqus UMAT subroutine in this study);(2)explicit incorporation of micro-scale features(e.g.,contact stiffness,particle size,porosity)to reveal their influences on macroscopic responses.An isotropic directional distribution density of contacts and three specific microstructures are considered,and their softening hyperelastic constitutive modulus tensors are explicitly derived.By introducing a softening factor and critical failure energy density,the model can describe geomaterial behaviors,simulating residual strength,X-shaped shear bands,and strain localization evolution.Numerical validations in comparison with themacro-scale hyperelastic model,Abaqus Drucker-Prager model,and the experiment confirm its accuracy.Parametric studies reveal critical dependencies:a normal to tangential contact stiffness ratio of 2-8(depending on stiffness magnitude),an internal length of 2-4 mm to ensure shear band formation,and a critical failure energy density(≤10 kJ/m^(3))to trigger strain softening and localization.Influences of the specific microstructures on strain localization and softening are investigated.The model also shows mesh independence due to the introduction of an internal length.The model’s applicability is further demonstrated by slope stability analysis,capturing slip surface evolution,and load-displacement characteristics.This study develops a robust microstructure-aware hyperelastic framework to describe the mechanical behaviors of granular materials,providing multiscale insights for geotechnical engineering applications.展开更多
We numerically investigate the effect of in-plane bending strain on valley-resolved conductance and valley polarization in a graphene nanoribbon with zigzag edges.The central region of the nanoribbon is bent into an a...We numerically investigate the effect of in-plane bending strain on valley-resolved conductance and valley polarization in a graphene nanoribbon with zigzag edges.The central region of the nanoribbon is bent into an arc with central angleφ.We find that the bending strain reduces the conductance but enhances the valley polarization.In the valley-resolved conductance spectra,there exist single-valley plateaus near the Dirac points and distinct Fano-type dips.Accordingly,a plateau of full valley polarization appears,which expands significantly at largeφ.At valleyresolved conductance dips,the valley polarization can be much larger than that in the unstrained case.The bending-induced enhancement of valley polarization can be explained by the features of pseudo-Landau levels in the bent region.Strain-induced valley polarization depends nonmonotonously on the nanoribbon width.These findings could be helpful in designing valleytronic devices with flexibility.展开更多
With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the...With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.展开更多
The photovoltaic performance of metal halide perovskite solar cells often respond divergently to environmental conditions during storage.In particular,light exposure can either enhance or degrade device efficiency,yet...The photovoltaic performance of metal halide perovskite solar cells often respond divergently to environmental conditions during storage.In particular,light exposure can either enhance or degrade device efficiency,yet the mechanisms underlying these antithetical behaviors are still under investigation.In this study,we explore the modulation of the open-circuit voltage(Voc)in triple-cation mixed-halide perovskite solar cells by systematically controlling storage environments.While light intensity exhibits minimal impact during storage,the spectral composition of illumination selectively enhances Voc comprising reversible and irreversible contributions.Structural characterization reveals that prolonged storage degrades the quality of perovskite crystals in the upper region of the perovskite layer,whereas light storage promotes the relaxation of microstrain at the buried interface with a p-type organic layer.This structural reorganization at the interface,accompanied by lattice expansion,accounts for suppressed nonradiative recombination and a corresponding increase in quasi-Fermi level splitting.Consequently,devices fabricated without chemical defect passivation achieve a power conversion efficiency of higher than 40%under indoor lighting conditions after preconditioned by continuous exposure to ambient light during storage.These findings highlight the critical role of controlled light exposure during storage not only in enhancing efficiency,but also in ensuring reproducibility of perovskite solar cell characterization.展开更多
Conglomerate rock's complex and heterogeneous microstructure significantly affects its mechanical properties,especially under dynamic loading.However,research on their dynamic behavior and fracture mechanisms is l...Conglomerate rock's complex and heterogeneous microstructure significantly affects its mechanical properties,especially under dynamic loading.However,research on their dynamic behavior and fracture mechanisms is limited.Through uniaxial compression tests and split Hopkinson pressure bar(SHPB)impact tests,the dynamic compressive mechanical properties and fracture mechanisms of conglomerate rock were studied.Nanoindentation and high-resolution X-ray computed tomography were employed to analyze the micro-mechanical behavior and internal structure of the conglomerate rock.Results indicate significant differences in mechanical properties between different gravel particles and cementing materials,with initial fractures primarily distributed at the gravel-cement interfaces.The dynamic mechanical properties of conglomerate rocks exhibit a clear strain rate dependency.Based on the stress−strain curves and failure characteristics,the dynamic compressive mechanical behavior can be categorized into two types using a critical strain rate.The dynamic compressive strength,peak strain,and toughness of conglomerate rock increased with the strain rate,with the strength at 54 s−1 being 2.6 times that at 6 s−1.The dynamic compressive fracture mechanism of conglomerate rock is related to the strain rate and microstructure;at low strain rates,gravel distribution is the key factor,whereas at high strain rates,gravel content becomes critical.展开更多
Central Sumatra,Indonesia,is historically known for its significant seismic activities,most notably the devastating 1883 earthquake.In this study,we measured the interseismic deformation using continuous GNSS observat...Central Sumatra,Indonesia,is historically known for its significant seismic activities,most notably the devastating 1883 earthquake.In this study,we measured the interseismic deformation using continuous GNSS observation data for three years from 2018 to 2021.5.The results show that the derived velocity fields indicate that the Central Sumatra deformation is primarily characterized by crustal strain shortening due to interaction between the India-Australian plate and the Sundaland plate.High strain values are observed along the Sumatran Fault Zone(SFZ),which is characterized by a history of significant seismic activity.Interseismic locking is divided into two segments.Segment A,located in the northern part of Siberut Island has an estimated moment magnitude of MW7.44 with a return period of200 years leading to a potential earthquake magnitude of MW8.98.Segment B in the southern part of Siberut Island has an estimated moment magnitude of MW7.26 with a return period of 200 years,resulting in a potential earthquake magnitude of MW8.79.The findings highlight critical seismic hazard implications,emphasizing the potential for a major earthquake in the Central Sumatra.展开更多
This study investigates the influence of loading frequency on the fatigue behavior of ballastless track concrete for high-speed railways,aiming to support the development of concrete capable of withstanding higher ope...This study investigates the influence of loading frequency on the fatigue behavior of ballastless track concrete for high-speed railways,aiming to support the development of concrete capable of withstanding higher operational speeds.Fatigue tests were conducted at loading frequencies ranging from 5 to 40 Hz,with a focus on fatigue life,damage evolution,energy dissipation,and residual fatigue strain in the concrete.The results indicate that between 5 and 15 Hz,the fatigue life and energy dissipation remain relatively stable,with minimal damage evolution and small residual strains.As the frequency increases to 15-20 Hz,the fatigue life and energy dissipation gradually decrease,while damage accumulation and residual strain increase.Beyond 20 Hz,both fatigue life and energy dissipation decrease rapidly,damage accumulation becomes more pronounced,and residual strain continues to rise.These phenomena are primarily attributed to the increased strain rate and load change rate at higher frequencies,which affect the microstructure evolution and lead to reduced fatigue performance.展开更多
基金financial support from NSF ExpandQISE program.The synthesis of tellurene was supported by NSF under grant no.CMMI-2046936supports from Purdue Research Foundation.
文摘Tellurene,a chiral chain semiconductor with a narrow bandgap and exceptional strain sensitivity,emerges as a pivotal material for tailoring electronic and optoelectronic properties via strain engineering.This study elucidates the fundamental mechanisms of ultrafast laser shock imprinting(LSI)in two-dimensional tellurium(Te),establishing a direct relationship between strain field orientation,mold topology,and anisotropic structural evolution.This is the first demonstration of ultrafast LSI on chiral chain Te unveiling orientation-sensitive dislocation networks.By applying controlled strain fields parallel or transverse to Te’s helical chains,we uncover two distinct deformation regimes.Strain aligned parallel to the chain’s direction induces gliding and rotation governed by weak interchain interactions,preserving covalent intrachain bonds and vibrational modes.In contrast,transverse strain drives shear-mediated multimodal deformations—tensile stretching,compression,and bending—resulting in significant lattice distortions and electronic property modulation.We discovered the critical role of mold topology on deformation:sharp-edged gratings generate localized shear forces surpassing those from homogeneous strain fields via smooth CD molds,triggering dislocation tangle formation,lattice reorientation,and inhomogeneous plastic deformation.Asymmetrical strain configurations enable localized structural transformations while retaining single-crystal integrity in adjacent regions—a balance essential for functional device integration.These insights position LSI as a precision tool for nanoscale strain engineering,capable of sculpting 2D material morphologies without compromising crystallinity.By bridging ultrafast mechanics with chiral chain material science,this work advances the design of strain-tunable devices for next-generation electronics and optoelectronics,while establishing a universal framework for manipulating anisotropic 2D systems under extreme strain rates.This work discovered crystallographic orientation-dependent deformation mechanisms in 2D Te,linking parallel strain to chain gliding and transverse strain to shear-driven multimodal distortion.It demonstrates mold geometry as a critical lever for strain localization and dislocation dynamics,with sharp-edged gratings enabling unprecedented control over lattice reorientation.Crucially,the identification of strain field conditions that reconcile severe plastic deformation with single-crystal retention offers a pathway to functional nanostructure fabrication,redefining LSI’s potential in ultrafast strain engineering of chiral chain materials.
文摘This paper investigates process parameter effects on microstructure and mechanical properties of the tubes processed via recently developed friction assisted tube straining(FATS)method.For this purpose,design of experiment was used to arrange finite element analyses and experimental tests.Numerical and experimental tests were executed by changing rotary speed,feed rate and die angle.Taguchi design results show that increasing feed rate and decreasing rotary speed enhance Zener-Hollomon(Z)parameter and decrease average grain size,while die angle has no considerable effect.Increasing Z value reduces grain size and enhances flow stress of the processed samples,while the experiment with the highest Z value refines initial microstructure from 40 to 8μm and increases flow stress by 5 times.
文摘The hot deformation characteristics of 1.4462 duplex stainless steel （DSS） were analyzed by considering strain partitioning between austenite and ferrite constituents. The individual behavior of ferrite and austenite in microstructure was studied in an iso-stress condition. Hot compression tests were performed at temperatures of 800-1100~C and strain rates of 0.001-1 s-1. The flow stress was modeled by a hyperbolic sine constitutive equation, the corresponding constants and apparent activation energies were determined for the studied alloys. The constitutive equation and law of mixture were used to measure the contribution factor of each phase at any given strain. It is found that the contribution factor of ferrite exponentially declines as the Zener-HoUomon parameter （Z） increases. On the contrary, the austenite contribution polynomially increases with the increase of Z. At low Z values below 2.6. x 1015 （lnZ---35.5）, a negative contribution factor is determined for austenite that is attributed to dynamic recrystallization. At high Z values, the contribution factor of austenite is about two orders of magnitude greater than that of ferrite, and therefore, austenite can accommodate more strain. Microstructural characterization via electron back-scattered diffraction （EBSD） confirms the mechanical results and shows that austenite recrystallization is possible only at high temperature and low strain rate.
基金financially supported by the Open Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,the Shanghai University and the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200)the Open fund of Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process(No.SHSYS202003)。
文摘The dynamic strain aging(DSA) behavior was investigated in GH4169 alloy during tensile deforming with electric-pulse current(EPC) at 750 ℃.The results show that DSA is restrained in the alloy when deformed with 40 Hz-EPC.The size ofγ " phase inner grains increases obviously and δ phase is facilitated to precipitate on grain boundary in the alloy applied with EPC,due to the promotion effect of EPC on the diffusion and segregation of atoms.Transmission electron microscopy(TEM)results indicate that dislocations can cut through small γ" precipitate with the size of less than 10 nm,while dislocations can only bypass dislocations when γ " precipitate grow up over 20 nm.The growth of precipitates consumes large amounts of atoms as well as the velocity of dislocation increase,which makes dislocations difficult to be pinned.Therefore,when γ" precipitates grow up to a large size more than the critical size of dislocation pinning,DSA is significantly restrained in the alloy after necking deformed with EPC.
基金the National Natural Science Foundation of China (Nos.51771082,51971009,52175410,51801076)the Six Talent Peaks Project in Jiangsu Province,China (No.2019-XCL-113)+2 种基金Zhenjiang Science & Technology Program,China (No.GY2020001)Project of Faculty of Agricultural Equipment of Jiangsu University,China (No.NZXB20200101)the US Department of Energy,Office of Science and Office of Basic Energy Science (No.DE-AC02-06CH11357) for providing the Advanced Photon Source。
文摘The mechanisms responsible for deformation behavior in Nb/NiTi composite during pre-straining were investigated systematically using in-situ synchrotron X-ray diffraction, transmission electron microscopy and tensile test. It is shown that upon loading, the composite experiences elastic elongation and slight plastic deformation of B19′,B2 and β-Nb phases, together with the forward stress-induced martensitic(SIM) transformation from B2 to B19′. Upon unloading, the deformation mechanisms of the composite mainly involve elastic recovery of B19′, B2 and β-Nb phases,compression deformation of β-Nb phase and incomplete B19′→B2 reverse SIM transformation. In the tensile loading-unloading procedure, besides the inherent elastic deformation and SIM transformation, the(001) compound twins in B19′ martensite can also be conducive to the elastic deformation occurring in B19′-phase of the composite.Therefore, this composite can exhibit a large recoverable strain after unloading owing to the elastic deformation, and the partially reversible and consecutive SIM transformation together with the(001) compound twins.
基金supported by the National Science Foundation for Distinguished Young Scholars of China(No.52325506)the Fundamental Research Funds for the Central Universities(No.DUT22LAB501)。
文摘Ultrasonic-Assisted Grinding(UAG)is a novel manufacturing technology that shows promising promise for use in processing Ceramic Matrix Composites(CMCs).Nevertheless,analyzing the material removal process of CMCs with multidirectional structure during UAG is challenging,impeding the progress and improvement of the UAG process.This work examined the impact of ultrasonic vibration on the dynamic mechanical characteristics during processing.Additionally,we experimentally elucidated the material removal mechanism of CMCs during the scratching process under the influence of vertical vibration.The results indicate that the introduction of ultrasonic vibration causes a strain rate effect,resulting in a modification of the material removal mechanism,subsequently impacting the processing quality.Ultrasonic vibration increases the dynamic strength and brittleness of the fibers in CMCs,leading to more cracks at fracture,which changes from the original bending fracture to shear fracture.In addition,ultrasonic vibration can effectively inhibit the impact of scratching depth and anisotropy on the removal mechanism of CMCs,resulting in a more uniform surface of CMCs after processing.
基金supported by the National KeyR&D Program of China(Grant No.2024YFB3817400)the National Natural Science Foundation of China(Grants No.12274276 and No.U24A6002)+1 种基金the Natural Science Foundation of Shanxi Province(China)(Grant No.202403021223008)Supported by Scientific and Technology Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2024Q017 and No.2025L043).
文摘Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabling topological functionalities in the post-Moore era.Here we review recent progress on two-dimensional(2D)magnetism in LTMCs,emphasizing material taxonomy,intrinsic magnetic properties,and external-field controls.This review first presents a classification of LTMCs by crystal structure and chemistry—binary halides,chalcogenides,and ternary families(e.g.,MPX_(3),M_(m)X_(n)Te_(k),MnBi_(2)Te_(4))—followed by a summary of their coupling mechanisms,ordering temperatures,and dimensional effects.It then analyzes the modulation of exchange interactions,magnetic anisotropy,and topological states by electric-field gating,strain engineering,and ion intercalation,with representative experimental demonstrations.Notable advances include room-temperature ferromagnetic metals and semiconductors,observation of the quantum anomalous Hall effect(QAHE)in MnBi2Te4,and synergistic control of magnetic-topological states under multiple external stimuli.Persistent challenges involve the limited availability of intrinsic 2D magnetic semiconductors with high Curie temperatures(Tc),incomplete understanding of the microscopic couplings at interfaces and under quantum confinement,and device-level stability.We conclude by outlining opportunities that lie in the integration of multiscale characterization,first-principles theory,and cross-scale fabrication to precisely co-engineer magnetism,topology,and electronic structure,thereby advancing LTMCs toward spintronic and topological-quantum applications.
文摘This study compared the acute effects of electrical energy transfer(TECAR) and transcutaneous electrical stimulation(TENS) on pain and flexibility after a hamstring injury. Young athletes received either a 20 min TECAR(n = 24) or TENS(n = 26) session within 5 days following a hamstring injury, while the control(CON, n = 25)group was instructed to rest. Visual analogue scale(VAS), functional Assessment Scale for Acute Hamstring Injuries(FASH), straight leg raise test(SLR), and sit-and-reach scores(STR) were obtained prior to, immediately,24, and 48 h after therapy. Group differences were detected after therapy in VAS and FASH scores(p < 0.05).Compared to pre-therapy measurements, VAS scores showed a greater decrease in the TECAR group(-38.75% to-63.33%) than in the TENS group(-16.67% to-25.00%) and both were greater than in the CON group(-2.81%to-9.81%)(p < 0.05). The TECAR group improved FASH scores(28.57%–48.21%) more than the TENS group(15.89%–27.79%) and both groups more than the CON group(0%–8.33%)(p < 0.05). The increase in SLR and STR was greater in the TECAR group(6.26%–13.96%) than in the TENS(1.72%–9.53%) and CON groups(0%–3.03%). These results suggest that in the acute phase of hamstring injury, the use of TECAR and, to a lesser extent, TENS may relieve pain symptoms and bring some improvements in flexibility more than instructing patients to rest.
基金Outstanding Talent in Tianjin(JC20230428)Young Scientific and Technological Talents(Level Three)in Tianjin(QN20230304)the National Key Research and Development Program of China(Grant Nos.AMMS-QNPY-2021-008,2021ZZKY02)。
文摘Ionogel,a novel flexible electronic material,presents a plethora of applications.Despite its potential,the fabrication of multifunctional ionogel with high-performance suitable for diverse scenarios remains a significant challenge.In this study,we prepare a multifunctional amphibious ionogel skin(AIGS)using a polymerizable ionic liquid(PIL)and a conductive ionic liquid(IL)in conjunction with titanium carbide(Ti_(3)C_(2)T_(x)-MXene).The resulting soft AIGS materials exhibit ductility,self-healing,and robust adhesion in mechanical properties due to non-covalent interactions,such as ion-dipole interactions and hydrogen bonding.They also demonstrate a wide sensing range(2%-400%),high sensing sensitivity(gauge factor(GF)up to 6.06),and stable sensing performance(good reliability and stability after strain)in electrical properties.The hydrophobic and dynamic viscoelastic network formed by extensive C-F bonds in the used polymer matrix,ensures the AIGS's suitability for amphibious environments.We find that AIGS has excellent triboelectric properties.Utilizing AIGS as a flexible electrode,a single-electrode triboelectric nanogenerator(SE-TENG)was constructed,achieving outstanding output performance(~300 V open-circuit voltage,172 nA short-circuit current,and 34 nC transferred charge).This device can power commercial portable electronic devices and identify different body movements.AIGS-based wearable strain sensors have also been shown to reliably detect human motion,including larger limb movements such as finger flexion and elbow flexion and extension,as well as subtle muscle movements such as frowning and swallowing.In addition,depending on the characteristics of the AIGS application in amphibious environments,the following functions can be realized simultaneously.AIGS in an aquatic environment combined with machine learning for intelligent recognition of breathing type,in an underwater environment combined with Morse code to convey simple information,and motion monitoring in an amphibious environment,demonstrates its potential feasibility in a variety of situations.
基金supported by the Program for National Natural Science Foundation of China(No.11675231)the Sichuan Science and Technology Program(Nos.2022YFG0263 and 2024NSFSC1097)the Scientific Research Starting Foundation for talents(Nos.21zx7109 and 22zx7175,24ycx1005).
文摘Single-crystal GaN epilayers were irradiated with heavy inert gas ions(2.3-MeV Ne^(8+),5.3-MeV Kr^(19+))to fluences ranging from 1.0×1.0^(11) to 1.0×1.0^(15)ions∕cm^(2).The strain-related damage accumulation versus ion fluences was studied using highresolution X-ray diffraction(HRXRD)and ultraviolet–visible(UV–Vis)spectroscopy.The results showed that the damage accumulation was mainly dominated by nuclear energy loss.When the ion fluence was less than∼0.055 displacement per atom(dpa),the lattice expansions and lattice strains markedly increased linearly with increasing ion fluences,accompanied by a slow enhancement in the dislocation densities,distortion parameters,and Urbach energy for both ion irradiations.Above this fluence(∼0.055 dpa),the lattice strains presented a slight increase,whereas a remarkable increase was observed in the dislocation densities,distortion parameters,and Urbach energy with the ion fluences after both ion irradiations.∼0.055 dpa is the threshold ion fluence for defect evolution and lattice damage related to strain.The mechanisms underlying the damage accumulation are discussed in detail.
基金financially supported by the fund from the Project of Evonik Operations GmbH(34.63.21010)Natural Science Foundation of Sichuan Province(2024NSFSC0304)。
文摘Background As probiotics,Bacillus strains may regulate some physiological functions in animals.This study aimed to evaluate whether dietary supplementation with a Bacillus-based probiotic could alleviate gut damage induced by rotavirus(RV)infection in piglets.Twenty-four piglets were randomly assigned into 2 groups fed with the basal diet(n=16)and the diet containing 10^(9) colony-forming unit Bacillus spores/kg(n=8).On d 8,8 piglets fed with the diet supplemented with Bacillus-based probiotic and 8 piglets fed with basal diet were orally infused with RV,while the residue piglets had oral gavage of sterile essential medium.The trial duration was 12 d.Results RV challenge induced diarrhea,significantly destroyed the morphology of jejunal mucosa(P<0.05),significantly increased RV-antibody and RV non-structural protein 4 of jejunal mucosa(P<0.05),significantly impaired antioxidant capacity(including malondialdehyde level,total antioxidant capacity and catalase activity),immunity(such as interleukin 2,interleukin 4 and secreted immunoglobulin A levels),mucins and the m RNA expression of tightjunction-related(such as Zonula occludens 1,occludin)and apoptotic-related(including B-cell lymphoma/leukaemia-2-associated X protein,B cell lymphoma/leukaemia-2,cysteinyl aspartate specific proteinases)genes of jejunal mucosa(P<0.05),and,to some extents,affected the bacteria community structure and abundance of ileal digesta in piglets.However,Bacillus-based probiotic administration could significantly attenuate the negative effects of RV infection on gut health of piglets(P<0.05).Conclusions These findings suggested that supplementing Bacillus-based probiotic in the diet could decrease diarrhea rate,and improve gut health in weaned piglets,which was associated with regulating intestinal antioxidant capacity,apoptosis,and microbiota.
基金Fundamental Research Funds for the Central Universities(SWU-XDJH202314).
文摘Conductive cotton fabrics have emerged as promising platforms for advanced wearable applications,including strain sensing,electrical heating,and photothermal conversion.However,their widespread adoption is hindered by several critical limitations:dependence on petroleum-based materials,inherent hydrophilicity,and insufficient durability in practical environments.To overcome these challenges,an eco-friendly,mussel-inspired conductive coating system comprising tannic acid,cellulose nanofibers,and carbon nanotubes is developed.Through a facile dip-coating approach followed by in situ tannic acid polymerization-induced surface roughening and octadecylamine modification,a superhydrophobic conductive cotton fabric combining exceptional flexibility,breathability,and environmental stability is fabricated.The resulting superhydrophobic conductive cotton fabric demonstrates outstanding strain-sensing performance,featuring a rapid response time(127 ms)and reliable signal output over 4000 stretching cycles,capable of precisely detecting various human motions even underwater.Furthermore,the superhydrophobic conductive cotton fabric achieves impressive electrothermal(103.9℃at 15 V)and photothermal(104.2℃at 350 mW cm^(-2))conversion efficiencies with excellent temperature controllability.This multifunctional fabric presents a sustainable solution for next-generation wearable electronics and intelligent thermal management systems,addressing both environmental concerns and performance requirements for real-world applications.
基金supported by the National Natural Science Foundation of China through grant numbers 12002245 and 12172263the Science and Technology Research Program of Chongqing Municipal Education Commission through grant number KJQN202300742+1 种基金the National Natural Science Foundation of ChongqingMunicipality through grant number CSTB2025NSCQ-GPX0841Chongqing Jiaotong University through grant number F1220038.
文摘Granular materials exhibit complex macroscopic mechanical behaviors closely related to their microscalemicrostructural features.Traditional macroscopic phenomenological elasto-plastic models,however,usually have complex formulations and lack explicit relations to these microstructural features.To avoid these limitations,this study proposes a micromechanics-based softening hyperelastic model for granular materials,integrating softening hyperelasticity withmicrostructural insights to capture strain softening,critical state,and strain localization behaviors.The model has two key advantages:(1)a clear conceptualization,straightforward formulation,and ease of numerical implementation(via Abaqus UMAT subroutine in this study);(2)explicit incorporation of micro-scale features(e.g.,contact stiffness,particle size,porosity)to reveal their influences on macroscopic responses.An isotropic directional distribution density of contacts and three specific microstructures are considered,and their softening hyperelastic constitutive modulus tensors are explicitly derived.By introducing a softening factor and critical failure energy density,the model can describe geomaterial behaviors,simulating residual strength,X-shaped shear bands,and strain localization evolution.Numerical validations in comparison with themacro-scale hyperelastic model,Abaqus Drucker-Prager model,and the experiment confirm its accuracy.Parametric studies reveal critical dependencies:a normal to tangential contact stiffness ratio of 2-8(depending on stiffness magnitude),an internal length of 2-4 mm to ensure shear band formation,and a critical failure energy density(≤10 kJ/m^(3))to trigger strain softening and localization.Influences of the specific microstructures on strain localization and softening are investigated.The model also shows mesh independence due to the introduction of an internal length.The model’s applicability is further demonstrated by slope stability analysis,capturing slip surface evolution,and load-displacement characteristics.This study develops a robust microstructure-aware hyperelastic framework to describe the mechanical behaviors of granular materials,providing multiscale insights for geotechnical engineering applications.
基金supported by the public welfare project(Normal Education Quality Improvement Plan)by the China Education Development Foundation(Grant No.TZJH202202)the National Natural Science Foundation of China(Grant No.12274370)。
文摘We numerically investigate the effect of in-plane bending strain on valley-resolved conductance and valley polarization in a graphene nanoribbon with zigzag edges.The central region of the nanoribbon is bent into an arc with central angleφ.We find that the bending strain reduces the conductance but enhances the valley polarization.In the valley-resolved conductance spectra,there exist single-valley plateaus near the Dirac points and distinct Fano-type dips.Accordingly,a plateau of full valley polarization appears,which expands significantly at largeφ.At valleyresolved conductance dips,the valley polarization can be much larger than that in the unstrained case.The bending-induced enhancement of valley polarization can be explained by the features of pseudo-Landau levels in the bent region.Strain-induced valley polarization depends nonmonotonously on the nanoribbon width.These findings could be helpful in designing valleytronic devices with flexibility.
基金financially supported by the National Natural Science Foundation of China(No.52073294)National Key R&D Program of China(No.2021YFB4000700)+1 种基金Project of Stable Support for Youth Team in Basic Research Field of the Chinese Academy of Sciences,China(No.YSBR-017)The authors are highly grateful to Mr.Fan-Ming Zhao for Cryogenic Mechanical Testing.
文摘With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.
基金supported by a National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2023-NR076521,RS-2025-00519481)the Research Grant of Kwangwoon University in 2023.
文摘The photovoltaic performance of metal halide perovskite solar cells often respond divergently to environmental conditions during storage.In particular,light exposure can either enhance or degrade device efficiency,yet the mechanisms underlying these antithetical behaviors are still under investigation.In this study,we explore the modulation of the open-circuit voltage(Voc)in triple-cation mixed-halide perovskite solar cells by systematically controlling storage environments.While light intensity exhibits minimal impact during storage,the spectral composition of illumination selectively enhances Voc comprising reversible and irreversible contributions.Structural characterization reveals that prolonged storage degrades the quality of perovskite crystals in the upper region of the perovskite layer,whereas light storage promotes the relaxation of microstrain at the buried interface with a p-type organic layer.This structural reorganization at the interface,accompanied by lattice expansion,accounts for suppressed nonradiative recombination and a corresponding increase in quasi-Fermi level splitting.Consequently,devices fabricated without chemical defect passivation achieve a power conversion efficiency of higher than 40%under indoor lighting conditions after preconditioned by continuous exposure to ambient light during storage.These findings highlight the critical role of controlled light exposure during storage not only in enhancing efficiency,but also in ensuring reproducibility of perovskite solar cell characterization.
基金Project(51978674)supported by the National Natural Science Foundation of China。
文摘Conglomerate rock's complex and heterogeneous microstructure significantly affects its mechanical properties,especially under dynamic loading.However,research on their dynamic behavior and fracture mechanisms is limited.Through uniaxial compression tests and split Hopkinson pressure bar(SHPB)impact tests,the dynamic compressive mechanical properties and fracture mechanisms of conglomerate rock were studied.Nanoindentation and high-resolution X-ray computed tomography were employed to analyze the micro-mechanical behavior and internal structure of the conglomerate rock.Results indicate significant differences in mechanical properties between different gravel particles and cementing materials,with initial fractures primarily distributed at the gravel-cement interfaces.The dynamic mechanical properties of conglomerate rocks exhibit a clear strain rate dependency.Based on the stress−strain curves and failure characteristics,the dynamic compressive mechanical behavior can be categorized into two types using a critical strain rate.The dynamic compressive strength,peak strain,and toughness of conglomerate rock increased with the strain rate,with the strength at 54 s−1 being 2.6 times that at 6 s−1.The dynamic compressive fracture mechanism of conglomerate rock is related to the strain rate and microstructure;at low strain rates,gravel distribution is the key factor,whereas at high strain rates,gravel content becomes critical.
文摘Central Sumatra,Indonesia,is historically known for its significant seismic activities,most notably the devastating 1883 earthquake.In this study,we measured the interseismic deformation using continuous GNSS observation data for three years from 2018 to 2021.5.The results show that the derived velocity fields indicate that the Central Sumatra deformation is primarily characterized by crustal strain shortening due to interaction between the India-Australian plate and the Sundaland plate.High strain values are observed along the Sumatran Fault Zone(SFZ),which is characterized by a history of significant seismic activity.Interseismic locking is divided into two segments.Segment A,located in the northern part of Siberut Island has an estimated moment magnitude of MW7.44 with a return period of200 years leading to a potential earthquake magnitude of MW8.98.Segment B in the southern part of Siberut Island has an estimated moment magnitude of MW7.26 with a return period of 200 years,resulting in a potential earthquake magnitude of MW8.79.The findings highlight critical seismic hazard implications,emphasizing the potential for a major earthquake in the Central Sumatra.
基金sponsored by the National Natural Science Foundation of China(Grant No.52438002)the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘This study investigates the influence of loading frequency on the fatigue behavior of ballastless track concrete for high-speed railways,aiming to support the development of concrete capable of withstanding higher operational speeds.Fatigue tests were conducted at loading frequencies ranging from 5 to 40 Hz,with a focus on fatigue life,damage evolution,energy dissipation,and residual fatigue strain in the concrete.The results indicate that between 5 and 15 Hz,the fatigue life and energy dissipation remain relatively stable,with minimal damage evolution and small residual strains.As the frequency increases to 15-20 Hz,the fatigue life and energy dissipation gradually decrease,while damage accumulation and residual strain increase.Beyond 20 Hz,both fatigue life and energy dissipation decrease rapidly,damage accumulation becomes more pronounced,and residual strain continues to rise.These phenomena are primarily attributed to the increased strain rate and load change rate at higher frequencies,which affect the microstructure evolution and lead to reduced fatigue performance.
