By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimizatio...By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimization of multiple primary reactions for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Many catalysts developed through entropy engineering have been built in nearly equimolar ratios to pursue high entropy,hindering the identification of the active sites and potentially diluting the concentration of real active sites while weakening their electronic interactions with reaction intermediates.Herein,this work proposes an entropy-engineering strategy in metal nanoparticle-embedded nitrogen carbon electrocatalysts,implemented by entropy-engineered Prussian blue analogs(PBA)as precursors to enhance the catalytic activity of primary Cu-Fe active sites.Through the introduction of the micro-strains driven by entropy engineering,density functional theory(DFT)calculations and geometric phase analysis(GPA)using Lorentz electron microscopy further elucidate the optimization of the adsorption/desorption of intermediates.Furthermore,the multi-dimensional morphology and the size diminishment of the nanocrystals serve to expand the electrochemical area,maximizing the catalytic activity for both ORR and OER.Notably,the Zn-air battery assembled with CuFeCoNiZn-NC operated for over 1300 h with negligible decay.This work presents a paradigm for the design of low-cost electrocatalysts with entropy engineering for multi-step reactions.展开更多
Successful polyethylene glycol fusion(PEG-fusion)of severed axons following peripheral nerve injuries for PEG-fused axons has been reported to:(1)rapidly restore electrophysiological continuity;(2)prevent distal Walle...Successful polyethylene glycol fusion(PEG-fusion)of severed axons following peripheral nerve injuries for PEG-fused axons has been reported to:(1)rapidly restore electrophysiological continuity;(2)prevent distal Wallerian Degeneration and maintain their myelin sheaths;(3)promote primarily motor,voluntary behavioral recoveries as assessed by the Sciatic Functional Index;and,(4)rapidly produce correct and incorrect connections in many possible combinations that produce rapid and extensive recovery of functional peripheral nervous system/central nervous system connections and reflex(e.g.,toe twitch)or voluntary behaviors.The preceding companion paper describes sensory terminal field reo rganization following PEG-fusion repair of sciatic nerve transections or ablations;howeve r,sensory behavioral recovery has not been explicitly explored following PEG-fusion repair.In the current study,we confirmed the success of PEG-fusion surgeries according to criteria(1-3)above and more extensively investigated whether PEG-fusion enhanced mechanical nociceptive recovery following sciatic transection in male and female outbred Sprague-Dawley and inbred Lewis rats.Mechanical nociceptive responses were assessed by measuring withdrawal thresholds using von Frey filaments on the dorsal and midplantar regions of the hindpaws.Dorsal von Frey filament tests were a more reliable method than plantar von Frey filament tests to assess mechanical nociceptive sensitivity following sciatic nerve transections.Baseline withdrawal thresholds of the sciatic-mediated lateral dorsal region differed significantly across strain but not sex.Withdrawal thresholds did not change significantly from baseline in chronic Unoperated and Sham-operated rats.Following sciatic transection,all rats exhibited severe hyposensitivity to stimuli at the lateral dorsal region of the hindpaw ipsilateral to the injury.However,PEG-fused rats exhibited significantly earlier return to baseline withdrawal thresholds than Negative Control rats.Furthermore,PEG-fused rats with significantly improved Sciatic Functional Index scores at or after 4 weeks postoperatively exhibited yet-earlier von Frey filament recove ry compared with those without Sciatic Functional Index recovery,suggesting a correlation between successful PEG-fusion and both motor-dominant and sensory-dominant behavioral recoveries.This correlation was independent of the sex or strain of the rat.Furthermore,our data showed that the acceleration of von Frey filament sensory recovery to baseline was solely due to the PEG-fused sciatic nerve and not saphenous nerve collateral outgrowths.No chronic hypersensitivity developed in any rat up to 12 weeks.All these data suggest that PEG-fusion repair of transection peripheral nerve injuries co uld have important clinical benefits.展开更多
Recent advances in strain engineering have enabled unprecedented control over quantum states in strongly correlated magnetic systems.However,nanoscale strain modulation of charge density waves(CDWs)and magnetically ex...Recent advances in strain engineering have enabled unprecedented control over quantum states in strongly correlated magnetic systems.However,nanoscale strain modulation of charge density waves(CDWs)and magnetically excited states,which is crucial for atomically precise strain engineering and practical spintronic applications,remains unexplored.Here,we report the nanoscale strain effects on CDWs and low-energy electronic states in the van der Waals antiferromagnetic metal GdTe_(3),utilizing scanning tunneling microscopy/spectroscopy.Lowtemperature cleavage introduces local strains,resulting in the formation of nanoscale wrinkles on the GdTe_(3)surface.Atomic displacement analysis reveals two distinct types of wrinkles:Wrinkle-I,originating from unidirectional strain,and Wrinkle-II,dominated by shear strain.In Wrinkle-I,the tensile strain enhances the CDW gap,while the compressive strain induces a single low-energy magnetic state.Wrinkle-II switches the orientation of CDW,leading to the formation of an associated CDW domain wall.In addition,three low-energy magnetic states that exhibit magnetic field-dependent shifts and intensity variations emerge within the CDW gap around Wrinkle-II,indicative of a strain-tuned coupling between CDW order and localized 4f-electron magnetism.These findings establish nanoscale strain as a powerful tuning knob for manipulating intertwined electronic and magnetic excitations in correlated magnetic systems.展开更多
Predicting cross-immunity between viral strains is vital for public health surveillance and vaccine development.Traditional neural network methods,such as BiLSTM,could be ineffective due to the lack of lab data for mo...Predicting cross-immunity between viral strains is vital for public health surveillance and vaccine development.Traditional neural network methods,such as BiLSTM,could be ineffective due to the lack of lab data for model training and the overshadowing of crucial features within sequence concatenation.The current work proposes a less data-consuming model incorporating a pre-trained gene sequence model and a mutual information inference operator.Our methodology utilizes gene alignment and deduplication algorithms to preprocess gene sequences,enhancing the model’s capacity to discern and focus on distinctions among input gene pairs.The model,i.e.,DNA Pretrained Cross-Immunity Protection Inference model(DPCIPI),outperforms state-of-theart(SOTA)models in predicting hemagglutination inhibition titer from influenza viral gene sequences only.Improvement in binary cross-immunity prediction is 1.58%in F1,2.34%in precision,1.57%in recall,and 1.57%in Accuracy.For multilevel cross-immunity improvements,the improvement is 2.12%in F1,3.50%in precision,2.19%in recall,and 2.19%in Accuracy.Our study showcases the potential of pre-trained gene models to improve predictions of antigenic variation and cross-immunity.With expanding gene data and advancements in pre-trained models,this approach promises significant impacts on vaccine development and public health.展开更多
Objectives This study aimed to explore the lagged and cumulative effects of risk factors on disability in older adults using distributed lag non-linear models(DLNMs).Methods We utilized data from the China Health and ...Objectives This study aimed to explore the lagged and cumulative effects of risk factors on disability in older adults using distributed lag non-linear models(DLNMs).Methods We utilized data from the China Health and Retirement Longitudinal Study(CHARLS).After feature selection via Elastic Net Regularization,we applied DLNMs to evaluate the lagged effects of risk factors.Disability was defined as the presence of any difficulties in basic activities of daily living(BADL).The cumulative relative risk(CRR)was calculated by summing the lag-specific risk estimates,representing the cumulative disability risk over the specified lag period.Effect modifications and sensitivity analyses were also performed.Results This study included a total of 2,318 participants.Early-phase lag factors,such as the difficulty in stooping(CRR=3.58;95%CI:2.31-5.55;P<0.001)and walking(CRR=2.77;95%CI:1.39-5.55;P<0.001),exerted the strongest effects immediately upon occurrence.Mid-phase lag factors,such as arthritis(CRR=1.51;95%CI:1.10-2.06;P=0.001),showed a resurgence in disability risk within 2-3 years.Late-phase lag factors,including depressive symptoms(CRR=2.38;95%CI:1.30-4.35;P<0.001)and elevated systolic blood pressure(CRR=1.64;95%CI:1.06-2.79;P=0.02),exhibited significant long-term cumulative risks.Conversely,grip strength(CRR=0.80;95%CI:0.54-0.95;P=0.02)and social participation(CRR=0.89;95%CI:0.73-0.99;P=0.04)were significant protective factors.Conclusions The findings underscore the importance of tailored interventions that account for various lag characteristics of different factors to effectively mitigate disability risk.Future studies should explore the underlying biological and sociological mechanisms of these lagged effects,identify intervention strategies that target risk factors with different lagged patterns,and evaluate their effectiveness.展开更多
Owing to their good biocompatibility,polysaccharide hydrogels have broad application prospects in the field of flexible strain sensors.However,there are still significant challenges in the preparation of polysaccharid...Owing to their good biocompatibility,polysaccharide hydrogels have broad application prospects in the field of flexible strain sensors.However,there are still significant challenges in the preparation of polysaccharide hydrogels with good mechanical properties.MCA-Li Cl hydrogels were prepared by introducing methacrylated hyaluronic acid(Me HA)into the polymer network in the presence of acrylic acid(AA),acryloyloxyethyltrimethyl ammonium chloride(CATAC),and metal ions.The polymer network not only has a chemically cross-linked network and a tough network structure,but also benefits from a variety of supramolecular interactions,such as hydrogen bonding and coordination covalent bonding,resulting in excellent mechanical properties,with an elongation at break of 1390%,a tensile strength of up to 1200 k Pa,a toughness of 9.4546 MJ/m^(3),and adhesive properties towards various substrates.At the same time,the hydrogel has a high conductivity(5.33 mS/cm)and high strain-sensing sensitivity(Gauge factor=2.55).The flexible strain sensor assembled from the prepared MCA-Li Cl hydrogel can be used to detect human movements,from micro-expressions(smiles,swallowing)to pulse signals and other physiological activities,as well as large-scale joint movements(wrists,elbows,knees,fingers,etc.),realizing the real-time monitoring of full-scale human movements.The prepared hydrogels have potential applications in wearable devices,electronic skin,and strain-sensor components.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
Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally ...Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally friendly solidstate strategy to improve refrigeration capacities and efficiencies.The second-order magnetic transition(SOMT)materials have broader△S_(M) peaks without thermal hysteresis,making them highly attractive in magnetic refrigeration,especially in the room temperature range.Here,we report a significant enhancement of△S_(M) at room temperature in single-crystal Mn_(5)Ge_(3).In this SOMT system,we realize a 60%improvement of-△S_(M)^(max) from 3.5 J/kg·K to 5.6 J/kg·K at T=300 K.This considerable enhancement of△S_(M) is achieved by intentionally introducing strain energy through high-pressure constrained deformation.Both experimental results and Monte Carlo simulations demonstrate that the enhancement of△S_(M) originates from the microscopic strain and lattice deformation induced by strain energy after deformation.This strain energy will reconstruct the energy landscape of this ferromagnetic system and enhance magnetization,resulting in a giant intensity of magnetocaloric responses.Our findings provide an approach to increase magnetic entropy change and may give fresh ideas for exploring advanced magnetocaloric materials.展开更多
A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relax...A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relaxation.Distributed optical fiber sensing was used to measure strains across the sample surface by helically wrapping the single-mode fiber around the cylindrical sample.Close agreement was observed between the circumferential strains obtained from the optical fibers and the extensometer.The reconstructed full-field strain contours show strain heterogeneity from the crack closure phase,and the strains in the later deformation phase are dominantly localized within the former high-strain zone.The Gini coefficient was used to quantify the degree of strain localization and shows an initial increase during the crack closure phase,a decrease during the linear elastic phase,and a subsequent increase during the post-yielding phase.This behavior corresponds to a process of initial localization from an imperfect boundary condition,homogenization,and eventual relocalization prior to the macroscopic failure of the sample.The transient strain rate decay during the stress relaxation phase was quantified using the p-value in the“Omori-like"power law function.A higher initial stress at the onset of relaxation results in a lower p-value,indicating a slower strain rate decay.As the sample approaches macroscopic failure,the lowest p-value shifts from the most damaged zone to adjacent areas,suggesting stress redistribution or crack propagation in deformed crystalline rocks under stress relaxation conditions.展开更多
This paper develops a semi-analytical solution for pile penetration in natural soft clays using the strain path method(SPM).The stress-strain behavior of soils is characterized by the S-CLAY1S model,which can capture ...This paper develops a semi-analytical solution for pile penetration in natural soft clays using the strain path method(SPM).The stress-strain behavior of soils is characterized by the S-CLAY1S model,which can capture the anisotropic evolution and destructuring nature of soft clays.By integrating the S-CLAY1S model into the theoretical framework of the SPM,a set of ordinary differential equations is formulated with respect to the vertical coordinate of soil particles.The distribution of excess pore water pressure(EPWP)following pile installation is approximated through one-dimensional(1D)radial integration around the pile shaft.The distribution of stresses and EPWP,along with the evolution of fabric anisotropy within the soil surrounding the pile,is presented to illustrate the response of pile penetration in natural soft clays.The proposed solution is validated against existing theoretical solutions using the SPM and cavity expansion method(CEM),along with experimental data.The findings demonstrate that the SPM reveals lower radial effective stresses and EPWP at the pile shaft than that of CEM.Pile penetration alters the soil's anisotropic properties,inducing rotational hardening and affecting post-installation stress distribution.Soil destructuration eliminates bonding among particles near the pile,resulting in a complete disruption of soil structure at the pile surface,which is particularly pronounced for higher initial soil structure ratios.Minimal variation was observed in the three principal stresses and shear stress on the cone side surface as the angle increased from 18°to 60°,except for a slight reduction in EPWP.展开更多
Conductive hydrogel-based stretchable electronics have been extensively investigated,among which strain sensors are the most prominently studied.While the mechanical properties significantly affect the performance of ...Conductive hydrogel-based stretchable electronics have been extensively investigated,among which strain sensors are the most prominently studied.While the mechanical properties significantly affect the performance of these devices,the systematic correlation between specific mechanical parameters and sensing performance remains rarely explored.This work compares the influences of Young’s modulus and mechanical hysteresis on the sensing performance between highly entangled PAM-Li and double-network PAM-Li-Agar-3 strain sensors.Owing to the brittle agar network,which imparts a higher Young’s modulus and pronounced mechanical hysteresis to the double-network PAMLi-Agar-3 hydrogel,the corresponding sensor requires a greater driving force for deformation and yields signals with poor reproducibility.In comparison,the PAM-Li hydrogel,characterized by highly entangled polymer chains,exhibits a lower Young’s modulus and negligible mechanical hysteresis.Consequently,signals from the PAM-Li strain sensor demonstrate enhanced sensitivity and stability.Therefore,this work demonstrates that a low Young’s modulus and minimal mechanical hysteresis are critical factors for achieving superior sensing performance in strain sensors,as systematically validated through comparative analyses across diverse application scenarios.展开更多
High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts,which significantly affected their b...High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts,which significantly affected their ballistic limits.In this paper,a fiber-scale experimental method for characterizing ultrahigh strain-rate transverse compression behavior was proposed.To begin with,in order to measure the extremely low stress and strain in small specimens,the conventional Hopkinson bar was reduced to the hundred-micron scale,thereby achieving wave impedance matching with single fibers.In addition,tangential and normal laser Doppler velocimetry(LDV)methods were employed to realize non-contact,high-precision,and high-speed axial velocity measurements of micron-scale incident and transmission bars,respectively.Meanwhile,a microscopic observation system was used to facilitate the installation of miniature fiber samples.The experimental setup and procedures were introduced,and the system accuracy was verified through sample-free loading tests based on one-dimensional stress wave propagation theory.Dynamic compression experiments on Graphene-UHMWPE fibers were carried out,followed by post-compression microstructural characterization via scanning electron microscopy(SEM).Results demonstrated that successful mechanical characterization was achieved at strain rates exceeding 105,an order of magnitude higher than the previously reported maximum rates.Furthermore,during the loading process,the fibers underwent uniform compression deformation while exhibiting pronounced strain-rate effects.This method offers a novel approach for dynamic mechanical characterization of microscale single fibers,enabling the development of comprehensive strain-ratedependent material models to guide the design of advanced composites and high-performance fibers.展开更多
Flexible bending strain sensors emerge as promising candidates for wearable health monitoring and human-machine interaction, owing to their high stability and sensitivity. However, a critical trade-off between high se...Flexible bending strain sensors emerge as promising candidates for wearable health monitoring and human-machine interaction, owing to their high stability and sensitivity. However, a critical trade-off between high sensitivity and reliable largeangle sensing capability persists as a key bottleneck, severely hindering their practical implementation. In this study, a synergistic material-structural engineering strategy is proposed to enhance the bend-sensing performance. Specifically, two core components of this strategy involve an in-house synthesized carbon-based conductive particulate ink with favorable printability and a rationally designed sensing layer structure. By integrating the two components via electrohydrodynamic printing technology, we successfully fabricated highly robust flexible bending strain sensors. The resulting sensors exhibit exceptional electromechanical responsiveness to bending deformation, including a wide operating range(10°–150°), high sensitivity(GF = 50.74), rapid response, low hysteresis, and excellent long-term stability. Practically, they can accurately capture diverse physiological signals, ranging from subtle carotid artery pulses to large elbow flexion. Furthermore, a wearable gesture recognition system, incorporating a printed flexible bending strain sensor array, was developed to enable precise gesture recognition, thereby realizing virtual flight control of an unmanned aerial vehicle. These results indicate that the proposed printed sensor provides a promising approach to the sensitivity-angle trade-off, thereby facilitating the practical implementation of flexible electronics in human-machine interaction.展开更多
The development of multifunctional intelligent textiles has become an important innovation direction in the field of textile engineering, under the dual demands of intelligent health monitoring and environmental prote...The development of multifunctional intelligent textiles has become an important innovation direction in the field of textile engineering, under the dual demands of intelligent health monitoring and environmental protection. Although singlefunctional textiles with antibacterial, photochromic, and strain-sensing properties have been developed, they are unable to meet the demand for multifunctional textiles. In this respect, this study developed a poly(lactic acid) and poly(3-hydroxybutyrate)/thermoplastic polyurethane/carbon black nanoparticle composite nanofiber yarn(PPTCY) with a hollow-core-sheath structure using a simple conjugate electrospinning technology. PPTCY possessed excellent mechanical strength and could be effectively woven. More importantly, it not only enabled real-time visual monitoring of ultraviolet(UV) intensity in the environment but also possessed excellent antibacterial properties and strain-sensing performance. Its ΔE value was up to 58.24, and its antibacterial rates against Escherichia coli and Staphylococcus aureus were both 99.99%. This fabric had excellent strainsensing performance, high linearity, and durability under both pressure and stretching deformations. This research provides favorable technical support for the application of intelligent textiles in the field of UV protection and traffic safety.展开更多
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
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t...Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.展开更多
To investigate the damage evolution caused by stress-driven and sub-critical crack propagation within the Beishan granite under multi-creep triaxial compressive conditions,the distributed optical fiber sensing and X-r...To investigate the damage evolution caused by stress-driven and sub-critical crack propagation within the Beishan granite under multi-creep triaxial compressive conditions,the distributed optical fiber sensing and X-ray computed tomography were combined to obtain the strain distribution over the sample surface and internal fractures of the samples.The Gini and skewness(G-S)coefficients were used to quantify strain localization during tests,where the Gini coefficient reflects the degree of clustering of elements with high strain values,i.e.,strain localization/delocalization.The strain localization-induced asymmetry of data distribution is quantified by the skewness coefficient.A precursor to granite failure is defined by the rapid and simultaneous increase of the G-S coefficients,which are calculated from strain increment,giving an earlier warning of failure by about 8%peak stress than those from absolute strain values.Moreover,the process of damage accumulation due to stress-driven crack propagation in Beishan granite is different at various confining pressures as the stress exceeds the crack initiation stress.Concretely,strain localization is continuous until brittle failure at higher confining pressure,while both strain localization and delocalization occur at lower confining pressure.Despite the different stress conditions,a similar statistical characteristic of strain localization during the creep stage is observed.The Gini coefficient increases,and the skewness coefficient decreases slightly as the creep stress is below 95%peak stress.When the accelerated strain localization begins,the Gini and skewness coefficients increase rapidly and simultaneously.展开更多
The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on ...The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on the mechanical performance of anchor rods,with limited attention to the coupled evolution of strain and temperature fields during tensile deformation.This knowledge gap hinders a comprehensive understanding of the synergistic mechanical-thermal response mechanisms in anchor rods under loading conditions.To address this limitation,the present study systematically investigated the evolution of strain and temperature fields,along with their correlation,during the test of micro-negative Poisson's ratio(NPR)and ordinary Poisson's ratio(PR)anchor rods.Digital image correlation(DIC)and infrared thermography(IRT)techniques were employed for this exploration.The uniaxial tensile tests were conducted at two different rates,and the ordinary PR anchor rod(Q235 anchor rod)was established as a control group for comparative analysis.The findings reveal that the micro-NPR anchor rod exhibit strain localization at multiple locations during the tensile process,whereas Q235 anchors show local strain concentration in only one region.The standard deviation evolution curves for both the strain and temperature field exhibit two distinct phases in the two anchor rods.The evolution patterns between these two types of curves are basically consistent.The two standard deviation curves for the micro-NPR anchor rod display a wavy increase in the second phase,while for the Q235 anchor rod,they increase steadily until the specimen is damaged.The correlation analysis reveals that the standard deviations of strain and temperature differences for both types of anchor rods are significantly correlated.These findings demonstrate the synergistic evolution mechanism of deformation and thermal response,providing a potential foundation for utilizing thermal monitoring to assess the stability of rock support structures.展开更多
Basins in western China produce hydrocarbons from 8,000 m deep and have been penetrated to 10,000 m,but the mechanical and petrophysical properties of deep and ultra-deep rocks are unclear and the origins of porosity ...Basins in western China produce hydrocarbons from 8,000 m deep and have been penetrated to 10,000 m,but the mechanical and petrophysical properties of deep and ultra-deep rocks are unclear and the origins of porosity and permeability remain a mystery.Our research used core samples from a depth of 7,600 m and mechanical tests to document the likely structural and porosity evolution of sandstone due to burial to 10,000 m.During triaxial tests,we characterized microstructure evolution using micro-CT scanning images and acoustic emissions and monitored stress and strain characteristics in high-temperature and high-pressure fluid environments.Under ultra deep-burial conditions,our samples deformed by pore collapse and pore distortion and brittle and ductile fracture,independently or concurrently.Under increasing triaxial stress,temperature and fluid pressure,sandstones initially lose porosity and permeability by pore collapse and compaction then develop a network of interconnected pores and fractures.Consequently,porosity can reach 8% to 18%,possibly accounting for fluid storage and flow capacity at depths of 10,000 m.Samples from 7,600 m lack substantial quartz,calcite cement and rapid burial for our samples and rocks at 10,000 m and quartz,calcite accumulation systematics suggests that though subject to temperatures of as much as 200°C,porosity loss and gain in sandstones at 10,000 m may be primarily due to compaction.Our tests show that due to pore collapse and grain fracture,sandstones having high initial porosity and permeability have a greater increase of porosity and permeability due to loading.展开更多
Soil desiccation cracking is a prevalent natural phenomenon that poses significant geotechnical and geoenvironmental challenges.Cracks typically initiate at surface defects such as air bubbles,large aggregates,tiny pi...Soil desiccation cracking is a prevalent natural phenomenon that poses significant geotechnical and geoenvironmental challenges.Cracks typically initiate at surface defects such as air bubbles,large aggregates,tiny pits,or uneven surfaces,where localized stress concentrations are readily induced.This study conducted a series of laboratory desiccation tests on slurry samples to investigate the initiation and propagation of desiccation cracks in the presence of varying types and quantities of surface defects.Digital image correlation(DIC)technology was employed to monitor the strain and displacement fields on the soil surface during the desiccation process.The results reveal that strain and displacement data derived from DIC can precisely predict the initiation sites and propagation directions of desiccation cracks.In samples with internal defects,cracks predominantly propagate through the defect,whereas external defects tend to initiate cracks along their edges.In samples with multiple defects,Y-shaped crack patterns generally form initially,followed by T-shaped and straight cracks,driven by the evolving stress field.The dynamic interplay between crack formation and tensile stress redistribution governs the initiation and propagation of desiccation cracks.展开更多
基金supported by the National Natural Science Foundation of China(52071083,52231007,12327804,52471224)Zhuhai Fudan Innovation Institute,and the Science and Technology Commission of Shanghai Municipality(23ZR1405000).
文摘By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimization of multiple primary reactions for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Many catalysts developed through entropy engineering have been built in nearly equimolar ratios to pursue high entropy,hindering the identification of the active sites and potentially diluting the concentration of real active sites while weakening their electronic interactions with reaction intermediates.Herein,this work proposes an entropy-engineering strategy in metal nanoparticle-embedded nitrogen carbon electrocatalysts,implemented by entropy-engineered Prussian blue analogs(PBA)as precursors to enhance the catalytic activity of primary Cu-Fe active sites.Through the introduction of the micro-strains driven by entropy engineering,density functional theory(DFT)calculations and geometric phase analysis(GPA)using Lorentz electron microscopy further elucidate the optimization of the adsorption/desorption of intermediates.Furthermore,the multi-dimensional morphology and the size diminishment of the nanocrystals serve to expand the electrochemical area,maximizing the catalytic activity for both ORR and OER.Notably,the Zn-air battery assembled with CuFeCoNiZn-NC operated for over 1300 h with negligible decay.This work presents a paradigm for the design of low-cost electrocatalysts with entropy engineering for multi-step reactions.
基金supported by DOD AFIRMⅢW81XWH-20-2-0029 subcontract,UT POC19-1774-13Neuraptive Therapeutics Inc.26-7724-56+1 种基金NIH R01-NS128086 grantsLone Star Paralysis gift(to GDB)。
文摘Successful polyethylene glycol fusion(PEG-fusion)of severed axons following peripheral nerve injuries for PEG-fused axons has been reported to:(1)rapidly restore electrophysiological continuity;(2)prevent distal Wallerian Degeneration and maintain their myelin sheaths;(3)promote primarily motor,voluntary behavioral recoveries as assessed by the Sciatic Functional Index;and,(4)rapidly produce correct and incorrect connections in many possible combinations that produce rapid and extensive recovery of functional peripheral nervous system/central nervous system connections and reflex(e.g.,toe twitch)or voluntary behaviors.The preceding companion paper describes sensory terminal field reo rganization following PEG-fusion repair of sciatic nerve transections or ablations;howeve r,sensory behavioral recovery has not been explicitly explored following PEG-fusion repair.In the current study,we confirmed the success of PEG-fusion surgeries according to criteria(1-3)above and more extensively investigated whether PEG-fusion enhanced mechanical nociceptive recovery following sciatic transection in male and female outbred Sprague-Dawley and inbred Lewis rats.Mechanical nociceptive responses were assessed by measuring withdrawal thresholds using von Frey filaments on the dorsal and midplantar regions of the hindpaws.Dorsal von Frey filament tests were a more reliable method than plantar von Frey filament tests to assess mechanical nociceptive sensitivity following sciatic nerve transections.Baseline withdrawal thresholds of the sciatic-mediated lateral dorsal region differed significantly across strain but not sex.Withdrawal thresholds did not change significantly from baseline in chronic Unoperated and Sham-operated rats.Following sciatic transection,all rats exhibited severe hyposensitivity to stimuli at the lateral dorsal region of the hindpaw ipsilateral to the injury.However,PEG-fused rats exhibited significantly earlier return to baseline withdrawal thresholds than Negative Control rats.Furthermore,PEG-fused rats with significantly improved Sciatic Functional Index scores at or after 4 weeks postoperatively exhibited yet-earlier von Frey filament recove ry compared with those without Sciatic Functional Index recovery,suggesting a correlation between successful PEG-fusion and both motor-dominant and sensory-dominant behavioral recoveries.This correlation was independent of the sex or strain of the rat.Furthermore,our data showed that the acceleration of von Frey filament sensory recovery to baseline was solely due to the PEG-fused sciatic nerve and not saphenous nerve collateral outgrowths.No chronic hypersensitivity developed in any rat up to 12 weeks.All these data suggest that PEG-fusion repair of transection peripheral nerve injuries co uld have important clinical benefits.
基金supported by the National Natural Science Foundation of China(Grant No.62488201)the National Key Research and Development Project of China(Grant No.2022YFA1204100)+1 种基金the Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-003)the Innovation Program of Quantum Science and Technology(Grant No.2021ZD0302700).
文摘Recent advances in strain engineering have enabled unprecedented control over quantum states in strongly correlated magnetic systems.However,nanoscale strain modulation of charge density waves(CDWs)and magnetically excited states,which is crucial for atomically precise strain engineering and practical spintronic applications,remains unexplored.Here,we report the nanoscale strain effects on CDWs and low-energy electronic states in the van der Waals antiferromagnetic metal GdTe_(3),utilizing scanning tunneling microscopy/spectroscopy.Lowtemperature cleavage introduces local strains,resulting in the formation of nanoscale wrinkles on the GdTe_(3)surface.Atomic displacement analysis reveals two distinct types of wrinkles:Wrinkle-I,originating from unidirectional strain,and Wrinkle-II,dominated by shear strain.In Wrinkle-I,the tensile strain enhances the CDW gap,while the compressive strain induces a single low-energy magnetic state.Wrinkle-II switches the orientation of CDW,leading to the formation of an associated CDW domain wall.In addition,three low-energy magnetic states that exhibit magnetic field-dependent shifts and intensity variations emerge within the CDW gap around Wrinkle-II,indicative of a strain-tuned coupling between CDW order and localized 4f-electron magnetism.These findings establish nanoscale strain as a powerful tuning knob for manipulating intertwined electronic and magnetic excitations in correlated magnetic systems.
基金supported by the Bill & Melinda Gates Foundation and the Minderoo Foundation
文摘Predicting cross-immunity between viral strains is vital for public health surveillance and vaccine development.Traditional neural network methods,such as BiLSTM,could be ineffective due to the lack of lab data for model training and the overshadowing of crucial features within sequence concatenation.The current work proposes a less data-consuming model incorporating a pre-trained gene sequence model and a mutual information inference operator.Our methodology utilizes gene alignment and deduplication algorithms to preprocess gene sequences,enhancing the model’s capacity to discern and focus on distinctions among input gene pairs.The model,i.e.,DNA Pretrained Cross-Immunity Protection Inference model(DPCIPI),outperforms state-of-theart(SOTA)models in predicting hemagglutination inhibition titer from influenza viral gene sequences only.Improvement in binary cross-immunity prediction is 1.58%in F1,2.34%in precision,1.57%in recall,and 1.57%in Accuracy.For multilevel cross-immunity improvements,the improvement is 2.12%in F1,3.50%in precision,2.19%in recall,and 2.19%in Accuracy.Our study showcases the potential of pre-trained gene models to improve predictions of antigenic variation and cross-immunity.With expanding gene data and advancements in pre-trained models,this approach promises significant impacts on vaccine development and public health.
基金supported by ScientificResearch Fund of National Health Commission of the People’s Republic of China-Major Science and Technology Program for Medicine and Health in Zhejiang Province(WKJ-ZJ-2406).
文摘Objectives This study aimed to explore the lagged and cumulative effects of risk factors on disability in older adults using distributed lag non-linear models(DLNMs).Methods We utilized data from the China Health and Retirement Longitudinal Study(CHARLS).After feature selection via Elastic Net Regularization,we applied DLNMs to evaluate the lagged effects of risk factors.Disability was defined as the presence of any difficulties in basic activities of daily living(BADL).The cumulative relative risk(CRR)was calculated by summing the lag-specific risk estimates,representing the cumulative disability risk over the specified lag period.Effect modifications and sensitivity analyses were also performed.Results This study included a total of 2,318 participants.Early-phase lag factors,such as the difficulty in stooping(CRR=3.58;95%CI:2.31-5.55;P<0.001)and walking(CRR=2.77;95%CI:1.39-5.55;P<0.001),exerted the strongest effects immediately upon occurrence.Mid-phase lag factors,such as arthritis(CRR=1.51;95%CI:1.10-2.06;P=0.001),showed a resurgence in disability risk within 2-3 years.Late-phase lag factors,including depressive symptoms(CRR=2.38;95%CI:1.30-4.35;P<0.001)and elevated systolic blood pressure(CRR=1.64;95%CI:1.06-2.79;P=0.02),exhibited significant long-term cumulative risks.Conversely,grip strength(CRR=0.80;95%CI:0.54-0.95;P=0.02)and social participation(CRR=0.89;95%CI:0.73-0.99;P=0.04)were significant protective factors.Conclusions The findings underscore the importance of tailored interventions that account for various lag characteristics of different factors to effectively mitigate disability risk.Future studies should explore the underlying biological and sociological mechanisms of these lagged effects,identify intervention strategies that target risk factors with different lagged patterns,and evaluate their effectiveness.
基金financially supported by the National Natural Science Foundation of China(No.22271074)Natural Science Foundation of Hebei Province(Nos.B2023208042,B2022208032,B2021208066,E2024208084,and E2024208088)+2 种基金Science Research Project of Hebei Education Department(No.JZX2024013)Special Fund for Local Scientific and Technological Development under the Guidance of the Central Government(No.236Z3704G)Hebei Province High Level Talent Funding(No.A202001010)。
文摘Owing to their good biocompatibility,polysaccharide hydrogels have broad application prospects in the field of flexible strain sensors.However,there are still significant challenges in the preparation of polysaccharide hydrogels with good mechanical properties.MCA-Li Cl hydrogels were prepared by introducing methacrylated hyaluronic acid(Me HA)into the polymer network in the presence of acrylic acid(AA),acryloyloxyethyltrimethyl ammonium chloride(CATAC),and metal ions.The polymer network not only has a chemically cross-linked network and a tough network structure,but also benefits from a variety of supramolecular interactions,such as hydrogen bonding and coordination covalent bonding,resulting in excellent mechanical properties,with an elongation at break of 1390%,a tensile strength of up to 1200 k Pa,a toughness of 9.4546 MJ/m^(3),and adhesive properties towards various substrates.At the same time,the hydrogel has a high conductivity(5.33 mS/cm)and high strain-sensing sensitivity(Gauge factor=2.55).The flexible strain sensor assembled from the prepared MCA-Li Cl hydrogel can be used to detect human movements,from micro-expressions(smiles,swallowing)to pulse signals and other physiological activities,as well as large-scale joint movements(wrists,elbows,knees,fingers,etc.),realizing the real-time monitoring of full-scale human movements.The prepared hydrogels have potential applications in wearable devices,electronic skin,and strain-sensor components.
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Project supported by the National Key Research and Decelopment Program of China(Grant No.2021YFB3500302)the National Natural Science Foundation of China(Grant Nos.U22A20116 and 52371200)the Innovation Capability Improvement Project of Hebei Province,China(Grant No.22567605H)。
文摘Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally friendly solidstate strategy to improve refrigeration capacities and efficiencies.The second-order magnetic transition(SOMT)materials have broader△S_(M) peaks without thermal hysteresis,making them highly attractive in magnetic refrigeration,especially in the room temperature range.Here,we report a significant enhancement of△S_(M) at room temperature in single-crystal Mn_(5)Ge_(3).In this SOMT system,we realize a 60%improvement of-△S_(M)^(max) from 3.5 J/kg·K to 5.6 J/kg·K at T=300 K.This considerable enhancement of△S_(M) is achieved by intentionally introducing strain energy through high-pressure constrained deformation.Both experimental results and Monte Carlo simulations demonstrate that the enhancement of△S_(M) originates from the microscopic strain and lattice deformation induced by strain energy after deformation.This strain energy will reconstruct the energy landscape of this ferromagnetic system and enhance magnetization,resulting in a giant intensity of magnetocaloric responses.Our findings provide an approach to increase magnetic entropy change and may give fresh ideas for exploring advanced magnetocaloric materials.
基金support of her postdoctoral research at the GFZ Helmholtz Centre for Geosciences.P.Pan acknowledges the financial support of the National Natural Science Foundation of China(Grant No.52339001)H.Hofmann and Y.Ji acknowledge the financial support of the Helmholtz Association's Initiative and Networking Fund for the Helmholtz Young Investigator Group ARES(contract number VH-NG-1516).
文摘A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relaxation.Distributed optical fiber sensing was used to measure strains across the sample surface by helically wrapping the single-mode fiber around the cylindrical sample.Close agreement was observed between the circumferential strains obtained from the optical fibers and the extensometer.The reconstructed full-field strain contours show strain heterogeneity from the crack closure phase,and the strains in the later deformation phase are dominantly localized within the former high-strain zone.The Gini coefficient was used to quantify the degree of strain localization and shows an initial increase during the crack closure phase,a decrease during the linear elastic phase,and a subsequent increase during the post-yielding phase.This behavior corresponds to a process of initial localization from an imperfect boundary condition,homogenization,and eventual relocalization prior to the macroscopic failure of the sample.The transient strain rate decay during the stress relaxation phase was quantified using the p-value in the“Omori-like"power law function.A higher initial stress at the onset of relaxation results in a lower p-value,indicating a slower strain rate decay.As the sample approaches macroscopic failure,the lowest p-value shifts from the most damaged zone to adjacent areas,suggesting stress redistribution or crack propagation in deformed crystalline rocks under stress relaxation conditions.
基金support from the National Natural Science Foundation of China(Grant No.42407256)the State Key Laboratory of Hydraulics and Mountain River Engineering,China(Grant No.SKHL2113)the Sichuan Science and Technology Program(Grant No.2024YFHZ0341).
文摘This paper develops a semi-analytical solution for pile penetration in natural soft clays using the strain path method(SPM).The stress-strain behavior of soils is characterized by the S-CLAY1S model,which can capture the anisotropic evolution and destructuring nature of soft clays.By integrating the S-CLAY1S model into the theoretical framework of the SPM,a set of ordinary differential equations is formulated with respect to the vertical coordinate of soil particles.The distribution of excess pore water pressure(EPWP)following pile installation is approximated through one-dimensional(1D)radial integration around the pile shaft.The distribution of stresses and EPWP,along with the evolution of fabric anisotropy within the soil surrounding the pile,is presented to illustrate the response of pile penetration in natural soft clays.The proposed solution is validated against existing theoretical solutions using the SPM and cavity expansion method(CEM),along with experimental data.The findings demonstrate that the SPM reveals lower radial effective stresses and EPWP at the pile shaft than that of CEM.Pile penetration alters the soil's anisotropic properties,inducing rotational hardening and affecting post-installation stress distribution.Soil destructuration eliminates bonding among particles near the pile,resulting in a complete disruption of soil structure at the pile surface,which is particularly pronounced for higher initial soil structure ratios.Minimal variation was observed in the three principal stresses and shear stress on the cone side surface as the angle increased from 18°to 60°,except for a slight reduction in EPWP.
基金supported by the National Natural Science Foundation of China(52303145,52403083)the Natural Science Foundation of Sichuan Province(2025ZNSFSC1400)supported by the start-up funding at Chengdu University(T202207)。
文摘Conductive hydrogel-based stretchable electronics have been extensively investigated,among which strain sensors are the most prominently studied.While the mechanical properties significantly affect the performance of these devices,the systematic correlation between specific mechanical parameters and sensing performance remains rarely explored.This work compares the influences of Young’s modulus and mechanical hysteresis on the sensing performance between highly entangled PAM-Li and double-network PAM-Li-Agar-3 strain sensors.Owing to the brittle agar network,which imparts a higher Young’s modulus and pronounced mechanical hysteresis to the double-network PAMLi-Agar-3 hydrogel,the corresponding sensor requires a greater driving force for deformation and yields signals with poor reproducibility.In comparison,the PAM-Li hydrogel,characterized by highly entangled polymer chains,exhibits a lower Young’s modulus and negligible mechanical hysteresis.Consequently,signals from the PAM-Li strain sensor demonstrate enhanced sensitivity and stability.Therefore,this work demonstrates that a low Young’s modulus and minimal mechanical hysteresis are critical factors for achieving superior sensing performance in strain sensors,as systematically validated through comparative analyses across diverse application scenarios.
基金financial support provided by the National Natural Science Foundation of China(Grant No.12302472)the Science and Technology Support Program of Jiangsu Province(Grant No.BK20230874)+2 种基金the Aeronautical Science Fund(ASF)(Grant No.2023Z057052005)the Research Fund of State Key Laboratory of Mechanics and Control for Aerospace Structures(Nanjing University of Aeronautics and Astronautics)(Grant No.MCAS-I-0124G02)the funding received from Jiangsu Hanvo Safety Product Co.,Ltd。
文摘High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts,which significantly affected their ballistic limits.In this paper,a fiber-scale experimental method for characterizing ultrahigh strain-rate transverse compression behavior was proposed.To begin with,in order to measure the extremely low stress and strain in small specimens,the conventional Hopkinson bar was reduced to the hundred-micron scale,thereby achieving wave impedance matching with single fibers.In addition,tangential and normal laser Doppler velocimetry(LDV)methods were employed to realize non-contact,high-precision,and high-speed axial velocity measurements of micron-scale incident and transmission bars,respectively.Meanwhile,a microscopic observation system was used to facilitate the installation of miniature fiber samples.The experimental setup and procedures were introduced,and the system accuracy was verified through sample-free loading tests based on one-dimensional stress wave propagation theory.Dynamic compression experiments on Graphene-UHMWPE fibers were carried out,followed by post-compression microstructural characterization via scanning electron microscopy(SEM).Results demonstrated that successful mechanical characterization was achieved at strain rates exceeding 105,an order of magnitude higher than the previously reported maximum rates.Furthermore,during the loading process,the fibers underwent uniform compression deformation while exhibiting pronounced strain-rate effects.This method offers a novel approach for dynamic mechanical characterization of microscale single fibers,enabling the development of comprehensive strain-ratedependent material models to guide the design of advanced composites and high-performance fibers.
基金supported by the Guangdong University Featured Innovation Program Project (Grant No.2024KTSCX043)the Guangdong Basic and Applied Basic Research Foundation (Grant Nos.2025A1515010967,2022A1515110621)+1 种基金the Innovation and Strong School Engineering Fund of Guangdong Province (Grant No.2025KCXTD047)the Guangdong Engineering Technology Research Center (Grant No.2021J020)。
文摘Flexible bending strain sensors emerge as promising candidates for wearable health monitoring and human-machine interaction, owing to their high stability and sensitivity. However, a critical trade-off between high sensitivity and reliable largeangle sensing capability persists as a key bottleneck, severely hindering their practical implementation. In this study, a synergistic material-structural engineering strategy is proposed to enhance the bend-sensing performance. Specifically, two core components of this strategy involve an in-house synthesized carbon-based conductive particulate ink with favorable printability and a rationally designed sensing layer structure. By integrating the two components via electrohydrodynamic printing technology, we successfully fabricated highly robust flexible bending strain sensors. The resulting sensors exhibit exceptional electromechanical responsiveness to bending deformation, including a wide operating range(10°–150°), high sensitivity(GF = 50.74), rapid response, low hysteresis, and excellent long-term stability. Practically, they can accurately capture diverse physiological signals, ranging from subtle carotid artery pulses to large elbow flexion. Furthermore, a wearable gesture recognition system, incorporating a printed flexible bending strain sensor array, was developed to enable precise gesture recognition, thereby realizing virtual flight control of an unmanned aerial vehicle. These results indicate that the proposed printed sensor provides a promising approach to the sensitivity-angle trade-off, thereby facilitating the practical implementation of flexible electronics in human-machine interaction.
基金supported by the Science and Technology Guidance Project of China National Textile and Apparel Council (Grant No.2024033)the Jiangsu Provincial Key Research and Development Program (Grant No.BE2019045)。
文摘The development of multifunctional intelligent textiles has become an important innovation direction in the field of textile engineering, under the dual demands of intelligent health monitoring and environmental protection. Although singlefunctional textiles with antibacterial, photochromic, and strain-sensing properties have been developed, they are unable to meet the demand for multifunctional textiles. In this respect, this study developed a poly(lactic acid) and poly(3-hydroxybutyrate)/thermoplastic polyurethane/carbon black nanoparticle composite nanofiber yarn(PPTCY) with a hollow-core-sheath structure using a simple conjugate electrospinning technology. PPTCY possessed excellent mechanical strength and could be effectively woven. More importantly, it not only enabled real-time visual monitoring of ultraviolet(UV) intensity in the environment but also possessed excellent antibacterial properties and strain-sensing performance. Its ΔE value was up to 58.24, and its antibacterial rates against Escherichia coli and Staphylococcus aureus were both 99.99%. This fabric had excellent strainsensing performance, high linearity, and durability under both pressure and stretching deformations. This research provides favorable technical support for the application of intelligent textiles in the field of UV protection and traffic safety.
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.
基金Supported by the National Natural Science Foundation of China under Grant No.51975138the High-Tech Ship Scientific Research Project from the Ministry of Industry and Information Technology under Grant No.CJ05N20the National Defense Basic Research Project under Grant No.JCKY2023604C006.
文摘Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.
基金supported by the National Natural Science Foundation of China(Grant No.52339001).
文摘To investigate the damage evolution caused by stress-driven and sub-critical crack propagation within the Beishan granite under multi-creep triaxial compressive conditions,the distributed optical fiber sensing and X-ray computed tomography were combined to obtain the strain distribution over the sample surface and internal fractures of the samples.The Gini and skewness(G-S)coefficients were used to quantify strain localization during tests,where the Gini coefficient reflects the degree of clustering of elements with high strain values,i.e.,strain localization/delocalization.The strain localization-induced asymmetry of data distribution is quantified by the skewness coefficient.A precursor to granite failure is defined by the rapid and simultaneous increase of the G-S coefficients,which are calculated from strain increment,giving an earlier warning of failure by about 8%peak stress than those from absolute strain values.Moreover,the process of damage accumulation due to stress-driven crack propagation in Beishan granite is different at various confining pressures as the stress exceeds the crack initiation stress.Concretely,strain localization is continuous until brittle failure at higher confining pressure,while both strain localization and delocalization occur at lower confining pressure.Despite the different stress conditions,a similar statistical characteristic of strain localization during the creep stage is observed.The Gini coefficient increases,and the skewness coefficient decreases slightly as the creep stress is below 95%peak stress.When the accelerated strain localization begins,the Gini and skewness coefficients increase rapidly and simultaneously.
基金supported by State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining&Technology,Beijing(Grant No.SKLGDUEK2120)。
文摘The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on the mechanical performance of anchor rods,with limited attention to the coupled evolution of strain and temperature fields during tensile deformation.This knowledge gap hinders a comprehensive understanding of the synergistic mechanical-thermal response mechanisms in anchor rods under loading conditions.To address this limitation,the present study systematically investigated the evolution of strain and temperature fields,along with their correlation,during the test of micro-negative Poisson's ratio(NPR)and ordinary Poisson's ratio(PR)anchor rods.Digital image correlation(DIC)and infrared thermography(IRT)techniques were employed for this exploration.The uniaxial tensile tests were conducted at two different rates,and the ordinary PR anchor rod(Q235 anchor rod)was established as a control group for comparative analysis.The findings reveal that the micro-NPR anchor rod exhibit strain localization at multiple locations during the tensile process,whereas Q235 anchors show local strain concentration in only one region.The standard deviation evolution curves for both the strain and temperature field exhibit two distinct phases in the two anchor rods.The evolution patterns between these two types of curves are basically consistent.The two standard deviation curves for the micro-NPR anchor rod display a wavy increase in the second phase,while for the Q235 anchor rod,they increase steadily until the specimen is damaged.The correlation analysis reveals that the standard deviations of strain and temperature differences for both types of anchor rods are significantly correlated.These findings demonstrate the synergistic evolution mechanism of deformation and thermal response,providing a potential foundation for utilizing thermal monitoring to assess the stability of rock support structures.
基金supported by the Fundamental Forward-looking Major Project of PetroChina(Grant No.2023ZZ02)the National Natural Science Foundation of China(Grant No.U22B600002).
文摘Basins in western China produce hydrocarbons from 8,000 m deep and have been penetrated to 10,000 m,but the mechanical and petrophysical properties of deep and ultra-deep rocks are unclear and the origins of porosity and permeability remain a mystery.Our research used core samples from a depth of 7,600 m and mechanical tests to document the likely structural and porosity evolution of sandstone due to burial to 10,000 m.During triaxial tests,we characterized microstructure evolution using micro-CT scanning images and acoustic emissions and monitored stress and strain characteristics in high-temperature and high-pressure fluid environments.Under ultra deep-burial conditions,our samples deformed by pore collapse and pore distortion and brittle and ductile fracture,independently or concurrently.Under increasing triaxial stress,temperature and fluid pressure,sandstones initially lose porosity and permeability by pore collapse and compaction then develop a network of interconnected pores and fractures.Consequently,porosity can reach 8% to 18%,possibly accounting for fluid storage and flow capacity at depths of 10,000 m.Samples from 7,600 m lack substantial quartz,calcite cement and rapid burial for our samples and rocks at 10,000 m and quartz,calcite accumulation systematics suggests that though subject to temperatures of as much as 200°C,porosity loss and gain in sandstones at 10,000 m may be primarily due to compaction.Our tests show that due to pore collapse and grain fracture,sandstones having high initial porosity and permeability have a greater increase of porosity and permeability due to loading.
基金supported by the National Natural Science Foundation of China(Grant Nos.42525201,42230710,42407521).
文摘Soil desiccation cracking is a prevalent natural phenomenon that poses significant geotechnical and geoenvironmental challenges.Cracks typically initiate at surface defects such as air bubbles,large aggregates,tiny pits,or uneven surfaces,where localized stress concentrations are readily induced.This study conducted a series of laboratory desiccation tests on slurry samples to investigate the initiation and propagation of desiccation cracks in the presence of varying types and quantities of surface defects.Digital image correlation(DIC)technology was employed to monitor the strain and displacement fields on the soil surface during the desiccation process.The results reveal that strain and displacement data derived from DIC can precisely predict the initiation sites and propagation directions of desiccation cracks.In samples with internal defects,cracks predominantly propagate through the defect,whereas external defects tend to initiate cracks along their edges.In samples with multiple defects,Y-shaped crack patterns generally form initially,followed by T-shaped and straight cracks,driven by the evolving stress field.The dynamic interplay between crack formation and tensile stress redistribution governs the initiation and propagation of desiccation cracks.
