UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechani...UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.展开更多
Physics-informed neural networks(PINNs)have emerged as a promising class of scientific machine learning techniques that integrate governing physical laws into neural network training.Their ability to enforce different...Physics-informed neural networks(PINNs)have emerged as a promising class of scientific machine learning techniques that integrate governing physical laws into neural network training.Their ability to enforce differential equations,constitutive relations,and boundary conditions within the loss function provides a physically grounded alternative to traditional data-driven models,particularly for solid and structural mechanics,where data are often limited or noisy.This review offers a comprehensive assessment of recent developments in PINNs,combining bibliometric analysis,theoretical foundations,application-oriented insights,and methodological innovations.A biblio-metric survey indicates a rapid increase in publications on PINNs since 2018,with prominent research clusters focused on numerical methods,structural analysis,and forecasting.Building upon this trend,the review consolidates advance-ments across five principal application domains,including forward structural analysis,inverse modeling and parameter identification,structural and topology optimization,assessment of structural integrity,and manufacturing processes.These applications are propelled by substantial methodological advancements,encompassing rigorous enforcement of boundary conditions,modified loss functions,adaptive training,domain decomposition strategies,multi-fidelity and transfer learning approaches,as well as hybrid finite element–PINN integration.These advances address recurring challenges in solid mechanics,such as high-order governing equations,material heterogeneity,complex geometries,localized phenomena,and limited experimental data.Despite remaining challenges in computational cost,scalability,and experimental validation,PINNs are increasingly evolving into specialized,physics-aware tools for practical solid and structural mechanics applications.展开更多
Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces ...Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces is a prerequisite for understanding the interaction and regulation between force and functions,which can be accomplished by traction force microscopy(TFM).In TFM,the forces are determined by tracking the displacement of fiducial markers through optical microscopy.The type of fiducial marker,microscopy modality,and image processing algorithms are key factors determining the final resolution of TFM.This review summarizes efforts in three aspects to enhance the performance of TFM and discusses the challenges of further development,particularly from an optical view.展开更多
Every developing country has plans.Five-year frameworks,industrial master plans and poverty reduction strategies accumulate in ministerial offices year after year.Shelves fill.Expectations rise.Outcomes lag.The proble...Every developing country has plans.Five-year frameworks,industrial master plans and poverty reduction strategies accumulate in ministerial offices year after year.Shelves fill.Expectations rise.Outcomes lag.The problem is rarely vision.It is execution.China’s annual Two Sessions offer a window for the outside world to understand China’s governance system.Formally,they are the concurrent meetings of the National People’s Congress(NPC)and the National Committee of the Chinese People’s Political Consultative Conference.Substantively,they function as the central coordination mechanism of a developmental state that treats governance as an exercise in disciplined delivery.展开更多
The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow ...The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow mechanics in the child’s nasal upper airway with adenoid hypertrophy,with an adenoid nasopharyngeal ratio(AN of 0.9),under cyclic inhalation and exhalation.An inlet respiratory cycle with three different flow rates(3.2 L/min calm breathing,8.6 L/min normal breathing,and 19.3 L/min intensive breathing)was simulated by using the computational fluid dynamics approach.To better capture the interaction between airflow and the flexible airway tissue,fluid-structure interaction analysis was performed at the normal breathing rate.Comparing the airflow dynamics during inhalation and exhalation,the pressure drops,nasal resistance,and wall shear stress show significant differences in the nasopharyngeal region for all different flow rates.This observation suggests that the inertial effect associated with the transient flow is important during exhalation and inhalation.Furthermore,the considerable temporal variation in flow rate distribution across a specific cross-section of the nasal airway highlights the critical role of transient data in virtual surgery planning and data for clinical decisions.展开更多
Incorporating ceramic particles into metal matrices is a proven strategy for boosting mechanical properties and wear resistance.The reinforcement potential of tungsten carbide(WC)particles in 316L stainless steel is r...Incorporating ceramic particles into metal matrices is a proven strategy for boosting mechanical properties and wear resistance.The reinforcement potential of tungsten carbide(WC)particles in 316L stainless steel is revealed,utilizing selective laser melting(SLM)to fabricate composites with 5 and 10 vol.%WC.The WC incorporation markedly alters the composite’s microstructure and mechanical attributes.Notably,5 vol.%WC-316L composite exhibits a refined submicron cellular structure,averaging 0.67μm in grain size.Elemental diffusion at WC-316L interface formed a 0.8μm gradient transition layer enriched with M_(2)C carbides(Fe,Cr,W),ensuring robust metallurgical bonding.Compared with unreinforced 316L,5%WC composite exhibits a 70%increase in tensile strength,reaching 1012.6 MPa,and a 25.3%rise in hardness,while maintaining acceptable ductility.10%WC composite achieves a 70.8%hardness enhancement,albeit with reduced elongation.Friction coefficient is reduced by up to 17.3%,and the wear mechanism shifts from adhesive to abrasive,significantly improving wear resistance.展开更多
In recent years,large language models(LLMs)have demonstrated immense potential in practical applications to enhance work efficiency and decision-making capabilities.However,specialized LLMs in the oil and gas engineer...In recent years,large language models(LLMs)have demonstrated immense potential in practical applications to enhance work efficiency and decision-making capabilities.However,specialized LLMs in the oil and gas engineering area are rarely developed.To aid in exploring and developing deep and ultra-deep unconventional reservoirs,there is a call for a personalized LLM on oil-and gas-related rock mechanics,which may handle complex professional data and make intelligent predictions and decisions.To that end,herein,we overview general and industry-specific LLMs.Then,a systematic workflow is proposed for building this domain-specific LLM for oil and gas engineering,including data collection and processing,model construction and training,model validation,and implementation in the specific domain.Moreover,three application scenarios are investigated:knowledge extraction from textural resources,field operation with multidisciplinary integration,and intelligent decision assistance.Finally,several challenges in developing this domain-specific LLM are highlighted.Our key findings are that geological surveys,laboratory experiments,field tests,and numerical simulations form the four original sources of rock mechanics data.Those data must flow through collection,storage,processing,and governance before being fed into LLM training.This domain-specific LLM can be trained by fine-tuning a general open-source LLM with professional data and constraints such as rock mechanics datasets and principles.The LLM can then follow the commonly used training and validation processes before being implemented in the oil and gas field.However,there are three primary challenges in building this domain-specific LLM:data standardization,data security and access,and striking a compromise between physics and data when building the model structure.Some of these challenges are administrative rather than technical,and overcoming those requires close collaboration between the different interested parties and various professional practitioners.展开更多
The crystallization of ionic crystals has traditionally been explained by Gibbs's classical nucleation theory.However,recent observations of intermediate phases during nucleation suggest that the process may be mo...The crystallization of ionic crystals has traditionally been explained by Gibbs's classical nucleation theory.However,recent observations of intermediate phases during nucleation suggest that the process may be more complex,necessitating new theoretical frameworks,though key empirical evidence remains elusive.In this study,we used microdroplets to investigate the crystallization of sodium halides(NaCl,NaBr,and NaI)under homogeneous nucleation conditions across a wide range of supersaturations.In the evaporating droplet,NaCl follows the classical nucleation pathway,whereas NaBr and NaI exhibit the formation of an intermediate phase prior to the nucleation of anhydrous and hydrous single crystals,respectively.Optical and computational analyses indicate that these intermediate phases are liquid crystal phases composed of contact ion pairs.These findings establish a new theoretical framework for crystal nucleation and growth and offer methods to control nucleation pathways,enabling us to achieve desired crystals regardless of specific conditions.展开更多
The predictive model and design of heavy-duty metal rubber shock absorber for the powertrains of heavy-load mining vehicles were investigated.The microstructural characteristics of the wire mesh were elucidated using ...The predictive model and design of heavy-duty metal rubber shock absorber for the powertrains of heavy-load mining vehicles were investigated.The microstructural characteristics of the wire mesh were elucidated using fractal graphs.A numerical model based on virtual fabrication technique was established to propose a design scheme for the wire mesh component.Four sets of wire mesh shock absorbers with various relative densities were prepared and a predictive model based on these relative densities was established through mechanical testing.To further enhance the predictive accuracy,a variable transposition fitting method was proposed to refine the model.Residual analysis was employed to quantitatively validate the results against those obtained from an experimental control group.The results show that the improved model exhibits higher predictive accuracy than the original model,with the determination coefficient(R^(2))of 0.9624.This study provides theoretical support for designing wire mesh shock absorbers with reduced testing requirements and enhanced design efficiency.展开更多
Nonclassical light fields exhibit unique quantum characteristics that not only expand the scope of optical research but also provide a solid foundation for advancements in quantum technologies.In this study,we investi...Nonclassical light fields exhibit unique quantum characteristics that not only expand the scope of optical research but also provide a solid foundation for advancements in quantum technologies.In this study,we investigate a system consisting of one-^(133)Cs atom placed in a resonant cavity.Pumped by 459 nm laser light,the system generates cavity modes corresponding to the atomic 7S_(1/2)→6P_(3/2)(1470 nm)and 7S_(1/2)→6P_(1/2)(1359 nm)transitions,which are associated with the clock states of the cesium active optical clock.By analyzing the statistical and dynamical properties of the fields,we systematically explore the nonclassical behavior of the system under varying coupling strengths and cavity decay rates.We identify parameter regions where both individual fields and their cross-correlation exhibit nonclassicality,with the Cauchy-Schwarz(CS)violation coefficient R reaching a maximum of 13.9.This demonstrates the system’s ability to generate highly nonclassical photon pairs,enriching the repertoire of nonclassical light sources.展开更多
Understanding the mechanical behavior of diagenetic mineral granules and interfaces in granite provides essential experimental references for constructing micromechanical models of granite.The micromechanical behavior...Understanding the mechanical behavior of diagenetic mineral granules and interfaces in granite provides essential experimental references for constructing micromechanical models of granite.The micromechanical behavior of Yanshanian granite is investigated using scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)and nanoindentation tests.The results demonstrate transitional mechanical properties at mineral interfaces.The elastic modulus and hardness exhibit intermediate values between adjacent mineral phases.The higher plasticity indices at the interfaces suggest higher plastic deformation capacity of hard-phase minerals in these regions.Additionally,fracture toughness measurements of minerals and interfaces were obtained,with interfacial values ranging from 0.90 to 1.63 MPa·m^(0.5).The analysis of mechanical property relationships shows a significant positive linear correlation between rock-scale elastic modulus and fracture toughness.However,this correlation is substantially lower at the mineral scale,demonstrating a scale effect in the relationship of different mechanical properties.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
Articular cartilage maintains joint homeostasis by adapting to mechanical loading,but both insufficient and excessive loading can impair cartilage integrity.Whether mechanical activity should be restricted in early os...Articular cartilage maintains joint homeostasis by adapting to mechanical loading,but both insufficient and excessive loading can impair cartilage integrity.Whether mechanical activity should be restricted in early osteoarthritis(OA),particularly among exercise enthusiasts,remains controversial.Here,we established in vitro and in vivo models of prolonged moderate mechanical loading(7.5%strain,1 Hz)and analyzed human cartilage from weight-bearing and non-weight-bearing regions using RNA sequencing.Prolonged exposure(≥12 h)significantly increased chondrocyte apoptosis(2.3-fold),reduced expression of the chondrogenic transcription factor SOX9 and the matrix markers COL2A1,and elevated nerve growth factor(NGF)expression(1.8-fold),accompanied by enrichment of neural sensitization and inflammatory pathways.Immunofluorescence staining revealed NGF accumulation in mechanically stressed cartilage.Unlike high-intensity stress,which led to immediate apoptosis,moderate loading induced a delayed pro-apoptotic response after 12 h.These findings indicate that prolonged moderate mechanical loading may promote chondrocyte apoptosis through an NGFmediated inflammatory microenvironment and provide mechanistic evidence suggesting that patients with early OA may benefit from limiting high-impact or prolonged moderate-intensity exercise sessions to prevent cartilage damage and guide rehabilitation.展开更多
Multi⁃field coupling problems involving species transport,heat transfer,substance transformation,and mechanical deformation are prevalent in various scenarios,such as the curing of early⁃age concretes,the response of ...Multi⁃field coupling problems involving species transport,heat transfer,substance transformation,and mechanical deformation are prevalent in various scenarios,such as the curing of early⁃age concretes,the response of soft materials,the oxidation of metals,the lithiation and delithiation of lithium⁃ion batteries,and the self⁃healing of biological tissues.Thermo⁃chemo⁃mechanical coupling dynamics are common characteristics of these problems,making theoretical studies on such processes of significant importance.This study offers a thorough review of advanced theoretical models that address thermo⁃chemo⁃mechanical behavior of solid materials within the theoretical framework of non⁃equilibrium thermodynamics.First,we outline the thermo⁃chemo⁃mechanical coupling phenomena observed in various application scenarios.Then,the theoretical developments of classical continuum mechanics include the phase field method and peridynamics in the contexts of thermo⁃mechanical coupling,chemo⁃mechanical coupling,and thermo⁃chemo⁃mechanical coupling,respectively.Finally,challenges faced by thermo⁃chemo⁃mechanical coupling research are highlighted and prospects and directions for this field are also outlined.This paper helps to understand the history and trends in the development of thermo⁃chemo⁃mechanical coupling theory.展开更多
The mechanical properties of biological soft tissues play a critical role in the study of biomechanics and the development of protective measures against human injury.Various testing techniques at different scales hav...The mechanical properties of biological soft tissues play a critical role in the study of biomechanics and the development of protective measures against human injury.Various testing techniques at different scales have been employed to characterize the mechanical behavior of soft tissues,which is essential for developing accurate tissue simulants and numerical models.This review comprehensively explores the mechanical properties of soft tissues,examining experimental methods,mechanical models,numerical simulations,and the progress in materials that mimic the mechanical performance of soft tissues.Finally,it reviews the damage and protection of human tissues under kinetic impacts,anticipating the future construction of soft tissue surrogate targets.The aim is to provide a systematic theoretical foundation and the latest advancements in the field,addressing the design,preparation,and quantitative modeling of biomimetic materials,thereby promoting the in-depth development of soft tissue mechanics and its applications.展开更多
On May 9,2025 on the campus of the University of Science and Technology of China(USTC),Chinese Academy of Sciences(CAS),an exhibition was unveiled to celebrate the UN International Year of Quantum Science and Technolo...On May 9,2025 on the campus of the University of Science and Technology of China(USTC),Chinese Academy of Sciences(CAS),an exhibition was unveiled to celebrate the UN International Year of Quantum Science and Technology(IYQ)-a one-year-long worldwide event in memory of the founding of quantum mechanics(QM).展开更多
The development of wearable electronics necessitates flexible and robust energy storage components to enhance comfort and battery longevity.The key to flexible batteries is improving electrochemical stability during d...The development of wearable electronics necessitates flexible and robust energy storage components to enhance comfort and battery longevity.The key to flexible batteries is improving electrochemical stability during deformation,which demands mechanical analysis for optimized design and manufacturing.This paper summarizes the progress of flexible batteries from a mechanical perspective,highlighting highly deformable structures such as fiber,wave,origami,and rigid-supple integrated designs.We discuss mechanical performance characterization and existing evaluation criteria for battery flexibility,along with simulation modeling and testing methods.Furthermore,we analyze mechano-electrochemical coupling,reviewing theoretical models that simulate mechanical and electrochemical behavior under various loads and introduce coupling tests that assess electrochemical performance during deformation.Finally,we suggest future research directions to advance flexible energy storage devices.展开更多
This paper presents a novel element differential method for modeling cracks in piezoelectric materials,aiming to simulate fracture behaviors and predict the fracture parameter known as the J-integral accurately.The me...This paper presents a novel element differential method for modeling cracks in piezoelectric materials,aiming to simulate fracture behaviors and predict the fracture parameter known as the J-integral accurately.The method leverages an efficient collocation technique to satisfy traction and electric charge equilibrium on the crack surface,aligning internal nodes with piezoelectric governing equations without needing integration or variational principles.It combines the strengths of the strong form collocation and finite element methods.The J-integral is derived analytically using the equivalent domain integral method,employing Green's formula and Gauss's divergence theorem to transform line integrals into area integrals for solving two-dimensional piezoelectric material problems.The accuracy of the method is validated through comparison with three typical examples,and it offers fracture prevention strategies for engineering piezoelectric structures under different electrical loading patterns.展开更多
Conventional geostress evaluation methods often assume static rock properties and neglect the dynamic degradation of mechanical parameters caused by damage evolution during drilling and fracturing processes,which sign...Conventional geostress evaluation methods often assume static rock properties and neglect the dynamic degradation of mechanical parameters caused by damage evolution during drilling and fracturing processes,which significantly limits prediction accuracy.To address this gap,this study develops a multiphysics-coupled numerical framework integrating COMSOL Multiphysics and MATLAB,grounded in damage mechanics theory,to quantitatively investigate the control mechanism of progressive rock damage on geostress redistribution.By establishing a damage constitutive model coupled with thermo-hydro-mechanical interactions,we simulate the dynamic evolution of rock damage and its impact on stress field reorganization during wellbore operations.Key results demonstrate that(1)incorporating damage evolution leads to substantial deviations in both the magnitude and spatial distribution of geostress,with stress perturbations highly localized within damage zones;(2)changes in mechanical parameters-particularly elastic modulus and permeability-dominate stress adjustments,with heightened sensitivity in formations with low elastic moduli and high permeability;and(3)Poisson's ratio has a negligible influence,whereas permeability variation becomes critically important in low-stiffness formations.Field validation via leakage case analyses in the Wujiaping Formation confirms that the proposed method significantly enhances prediction accuracy compared with conventional approaches.This work elucidates the multiscale interdependency between damage and stress evolution by offering a physics-based framework to optimize drilling and stimulation design in heterogeneous reservoirs.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52303298 and 52233002)。
文摘UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.
基金funded by National Research Council of Thailand(contract No.N42A671047).
文摘Physics-informed neural networks(PINNs)have emerged as a promising class of scientific machine learning techniques that integrate governing physical laws into neural network training.Their ability to enforce differential equations,constitutive relations,and boundary conditions within the loss function provides a physically grounded alternative to traditional data-driven models,particularly for solid and structural mechanics,where data are often limited or noisy.This review offers a comprehensive assessment of recent developments in PINNs,combining bibliometric analysis,theoretical foundations,application-oriented insights,and methodological innovations.A biblio-metric survey indicates a rapid increase in publications on PINNs since 2018,with prominent research clusters focused on numerical methods,structural analysis,and forecasting.Building upon this trend,the review consolidates advance-ments across five principal application domains,including forward structural analysis,inverse modeling and parameter identification,structural and topology optimization,assessment of structural integrity,and manufacturing processes.These applications are propelled by substantial methodological advancements,encompassing rigorous enforcement of boundary conditions,modified loss functions,adaptive training,domain decomposition strategies,multi-fidelity and transfer learning approaches,as well as hybrid finite element–PINN integration.These advances address recurring challenges in solid mechanics,such as high-order governing equations,material heterogeneity,complex geometries,localized phenomena,and limited experimental data.Despite remaining challenges in computational cost,scalability,and experimental validation,PINNs are increasingly evolving into specialized,physics-aware tools for practical solid and structural mechanics applications.
基金supported by the Major Research Instrument Development Project of the National Natural Science Foundation of China(32527801)the National Natural Science Foundation of China(32301168)+1 种基金the Ningbo Natural Science Foundation of China(2023J351)the Yongjiang Innovative Talents Project of Ningbo City(2024A-172-G).
文摘Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces is a prerequisite for understanding the interaction and regulation between force and functions,which can be accomplished by traction force microscopy(TFM).In TFM,the forces are determined by tracking the displacement of fiducial markers through optical microscopy.The type of fiducial marker,microscopy modality,and image processing algorithms are key factors determining the final resolution of TFM.This review summarizes efforts in three aspects to enhance the performance of TFM and discusses the challenges of further development,particularly from an optical view.
文摘Every developing country has plans.Five-year frameworks,industrial master plans and poverty reduction strategies accumulate in ministerial offices year after year.Shelves fill.Expectations rise.Outcomes lag.The problem is rarely vision.It is execution.China’s annual Two Sessions offer a window for the outside world to understand China’s governance system.Formally,they are the concurrent meetings of the National People’s Congress(NPC)and the National Committee of the Chinese People’s Political Consultative Conference.Substantively,they function as the central coordination mechanism of a developmental state that treats governance as an exercise in disciplined delivery.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0707601).
文摘The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow mechanics in the child’s nasal upper airway with adenoid hypertrophy,with an adenoid nasopharyngeal ratio(AN of 0.9),under cyclic inhalation and exhalation.An inlet respiratory cycle with three different flow rates(3.2 L/min calm breathing,8.6 L/min normal breathing,and 19.3 L/min intensive breathing)was simulated by using the computational fluid dynamics approach.To better capture the interaction between airflow and the flexible airway tissue,fluid-structure interaction analysis was performed at the normal breathing rate.Comparing the airflow dynamics during inhalation and exhalation,the pressure drops,nasal resistance,and wall shear stress show significant differences in the nasopharyngeal region for all different flow rates.This observation suggests that the inertial effect associated with the transient flow is important during exhalation and inhalation.Furthermore,the considerable temporal variation in flow rate distribution across a specific cross-section of the nasal airway highlights the critical role of transient data in virtual surgery planning and data for clinical decisions.
基金supported by Opening funding of National Key Laboratory of Aerospace Liquid Propulsion(HTKJ2024KL011004)Aeronautical Science Fund of China(ASFC-20240042070001)+2 种基金Opening funding of State Key Laboratory of Metal Forming Technology and Heavy Equipment(B2408100.W05)National Key R&D Program of China(2022YFB4601804)National Natural Science Foundation of China(52250287,52275375).
文摘Incorporating ceramic particles into metal matrices is a proven strategy for boosting mechanical properties and wear resistance.The reinforcement potential of tungsten carbide(WC)particles in 316L stainless steel is revealed,utilizing selective laser melting(SLM)to fabricate composites with 5 and 10 vol.%WC.The WC incorporation markedly alters the composite’s microstructure and mechanical attributes.Notably,5 vol.%WC-316L composite exhibits a refined submicron cellular structure,averaging 0.67μm in grain size.Elemental diffusion at WC-316L interface formed a 0.8μm gradient transition layer enriched with M_(2)C carbides(Fe,Cr,W),ensuring robust metallurgical bonding.Compared with unreinforced 316L,5%WC composite exhibits a 70%increase in tensile strength,reaching 1012.6 MPa,and a 25.3%rise in hardness,while maintaining acceptable ductility.10%WC composite achieves a 70.8%hardness enhancement,albeit with reduced elongation.Friction coefficient is reduced by up to 17.3%,and the wear mechanism shifts from adhesive to abrasive,significantly improving wear resistance.
基金supported by the National Natural Science Foundation of China(no.42277122)the Science Foun-dation of the China University of Petroleum,Beijing(No.2462024BJRC013).
文摘In recent years,large language models(LLMs)have demonstrated immense potential in practical applications to enhance work efficiency and decision-making capabilities.However,specialized LLMs in the oil and gas engineering area are rarely developed.To aid in exploring and developing deep and ultra-deep unconventional reservoirs,there is a call for a personalized LLM on oil-and gas-related rock mechanics,which may handle complex professional data and make intelligent predictions and decisions.To that end,herein,we overview general and industry-specific LLMs.Then,a systematic workflow is proposed for building this domain-specific LLM for oil and gas engineering,including data collection and processing,model construction and training,model validation,and implementation in the specific domain.Moreover,three application scenarios are investigated:knowledge extraction from textural resources,field operation with multidisciplinary integration,and intelligent decision assistance.Finally,several challenges in developing this domain-specific LLM are highlighted.Our key findings are that geological surveys,laboratory experiments,field tests,and numerical simulations form the four original sources of rock mechanics data.Those data must flow through collection,storage,processing,and governance before being fed into LLM training.This domain-specific LLM can be trained by fine-tuning a general open-source LLM with professional data and constraints such as rock mechanics datasets and principles.The LLM can then follow the commonly used training and validation processes before being implemented in the oil and gas field.However,there are three primary challenges in building this domain-specific LLM:data standardization,data security and access,and striking a compromise between physics and data when building the model structure.Some of these challenges are administrative rather than technical,and overcoming those requires close collaboration between the different interested parties and various professional practitioners.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2021R1C1C2006535)supported by the Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Korea government(MSIT)(No.RS-2024-00403164)supported by the National Research Foundation of Korea grant funded by the Korea government,Ministry of Science and ICT(Development of Nanofiber Yarn Based Compound Sensor as a Comprehensive Wearable Healthcare Solution)(Grant No.RS-2024-00357296).
文摘The crystallization of ionic crystals has traditionally been explained by Gibbs's classical nucleation theory.However,recent observations of intermediate phases during nucleation suggest that the process may be more complex,necessitating new theoretical frameworks,though key empirical evidence remains elusive.In this study,we used microdroplets to investigate the crystallization of sodium halides(NaCl,NaBr,and NaI)under homogeneous nucleation conditions across a wide range of supersaturations.In the evaporating droplet,NaCl follows the classical nucleation pathway,whereas NaBr and NaI exhibit the formation of an intermediate phase prior to the nucleation of anhydrous and hydrous single crystals,respectively.Optical and computational analyses indicate that these intermediate phases are liquid crystal phases composed of contact ion pairs.These findings establish a new theoretical framework for crystal nucleation and growth and offer methods to control nucleation pathways,enabling us to achieve desired crystals regardless of specific conditions.
基金National Natural Science Foundation of China(12262028)Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT22085)Inner Mongolia Autonomous Region Science and Technology Plan Project(2021GG0437)。
文摘The predictive model and design of heavy-duty metal rubber shock absorber for the powertrains of heavy-load mining vehicles were investigated.The microstructural characteristics of the wire mesh were elucidated using fractal graphs.A numerical model based on virtual fabrication technique was established to propose a design scheme for the wire mesh component.Four sets of wire mesh shock absorbers with various relative densities were prepared and a predictive model based on these relative densities was established through mechanical testing.To further enhance the predictive accuracy,a variable transposition fitting method was proposed to refine the model.Residual analysis was employed to quantitatively validate the results against those obtained from an experimental control group.The results show that the improved model exhibits higher predictive accuracy than the original model,with the determination coefficient(R^(2))of 0.9624.This study provides theoretical support for designing wire mesh shock absorbers with reduced testing requirements and enhanced design efficiency.
基金supported by CAS Project for National Time Service Center(Grant No.E239SC1101)Young Scientists in Basic Research(Grant No.YSBR-085).
文摘Nonclassical light fields exhibit unique quantum characteristics that not only expand the scope of optical research but also provide a solid foundation for advancements in quantum technologies.In this study,we investigate a system consisting of one-^(133)Cs atom placed in a resonant cavity.Pumped by 459 nm laser light,the system generates cavity modes corresponding to the atomic 7S_(1/2)→6P_(3/2)(1470 nm)and 7S_(1/2)→6P_(1/2)(1359 nm)transitions,which are associated with the clock states of the cesium active optical clock.By analyzing the statistical and dynamical properties of the fields,we systematically explore the nonclassical behavior of the system under varying coupling strengths and cavity decay rates.We identify parameter regions where both individual fields and their cross-correlation exhibit nonclassicality,with the Cauchy-Schwarz(CS)violation coefficient R reaching a maximum of 13.9.This demonstrates the system’s ability to generate highly nonclassical photon pairs,enriching the repertoire of nonclassical light sources.
基金funded by the National Natural Science Foundation of China(Nos.52422403 and U22A20166)the Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(No.2024ZD1003903)+1 种基金the Department of Science and Technology of Guangdong Province(No.2019ZT08G315)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012654).
文摘Understanding the mechanical behavior of diagenetic mineral granules and interfaces in granite provides essential experimental references for constructing micromechanical models of granite.The micromechanical behavior of Yanshanian granite is investigated using scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)and nanoindentation tests.The results demonstrate transitional mechanical properties at mineral interfaces.The elastic modulus and hardness exhibit intermediate values between adjacent mineral phases.The higher plasticity indices at the interfaces suggest higher plastic deformation capacity of hard-phase minerals in these regions.Additionally,fracture toughness measurements of minerals and interfaces were obtained,with interfacial values ranging from 0.90 to 1.63 MPa·m^(0.5).The analysis of mechanical property relationships shows a significant positive linear correlation between rock-scale elastic modulus and fracture toughness.However,this correlation is substantially lower at the mineral scale,demonstrating a scale effect in the relationship of different mechanical properties.
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 Zhejiang Medical and Health Innovation Talent Support Project(Grant No.2021RC128 to S.S.)Zhejiang Medicine and Health Science and Technology Project(2025KY1540 to J.J.L.)+3 种基金Zhejiang Province Health Science and Technology Project(2024KY409 and 2021KY1086 to J.Y.L.)Huzhou Science and Technology Planning Project(2020GY10 to W.L.,2022GZ65 to J.Y.L.)Huzhou Basic and Clinical Translation of Orthopedics Key Laboratory(Grant No.HZGKSYS01Y to S.S.)South Taihu Lake Outstanding Young Health Talents Cultivation Program(Grant No.rsk2023001 to S.S.).
文摘Articular cartilage maintains joint homeostasis by adapting to mechanical loading,but both insufficient and excessive loading can impair cartilage integrity.Whether mechanical activity should be restricted in early osteoarthritis(OA),particularly among exercise enthusiasts,remains controversial.Here,we established in vitro and in vivo models of prolonged moderate mechanical loading(7.5%strain,1 Hz)and analyzed human cartilage from weight-bearing and non-weight-bearing regions using RNA sequencing.Prolonged exposure(≥12 h)significantly increased chondrocyte apoptosis(2.3-fold),reduced expression of the chondrogenic transcription factor SOX9 and the matrix markers COL2A1,and elevated nerve growth factor(NGF)expression(1.8-fold),accompanied by enrichment of neural sensitization and inflammatory pathways.Immunofluorescence staining revealed NGF accumulation in mechanically stressed cartilage.Unlike high-intensity stress,which led to immediate apoptosis,moderate loading induced a delayed pro-apoptotic response after 12 h.These findings indicate that prolonged moderate mechanical loading may promote chondrocyte apoptosis through an NGFmediated inflammatory microenvironment and provide mechanistic evidence suggesting that patients with early OA may benefit from limiting high-impact or prolonged moderate-intensity exercise sessions to prevent cartilage damage and guide rehabilitation.
基金Sponsored by Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515111166)Development and Reform Commission of Shenzhen(Grant No.XMHT20220103004)+1 种基金Shenzhen Natural Science Fund(Grant No.GXWD20231130100351002)National Natural Science Foundation of China(Grant No.11932005).
文摘Multi⁃field coupling problems involving species transport,heat transfer,substance transformation,and mechanical deformation are prevalent in various scenarios,such as the curing of early⁃age concretes,the response of soft materials,the oxidation of metals,the lithiation and delithiation of lithium⁃ion batteries,and the self⁃healing of biological tissues.Thermo⁃chemo⁃mechanical coupling dynamics are common characteristics of these problems,making theoretical studies on such processes of significant importance.This study offers a thorough review of advanced theoretical models that address thermo⁃chemo⁃mechanical behavior of solid materials within the theoretical framework of non⁃equilibrium thermodynamics.First,we outline the thermo⁃chemo⁃mechanical coupling phenomena observed in various application scenarios.Then,the theoretical developments of classical continuum mechanics include the phase field method and peridynamics in the contexts of thermo⁃mechanical coupling,chemo⁃mechanical coupling,and thermo⁃chemo⁃mechanical coupling,respectively.Finally,challenges faced by thermo⁃chemo⁃mechanical coupling research are highlighted and prospects and directions for this field are also outlined.This paper helps to understand the history and trends in the development of thermo⁃chemo⁃mechanical coupling theory.
基金supported by the National Natural Science Foundation of China(Grant No.U2241273)the Beijing Municipal Natural Science Foundation(Grant No.Z240017)+3 种基金the 111 project(Grant No.B13003)the Fundamental Research Funds for the Central Universitiesthe China Scholarship Councilthe Academic Excellence Foundation of BUAA for PhD Students.
文摘The mechanical properties of biological soft tissues play a critical role in the study of biomechanics and the development of protective measures against human injury.Various testing techniques at different scales have been employed to characterize the mechanical behavior of soft tissues,which is essential for developing accurate tissue simulants and numerical models.This review comprehensively explores the mechanical properties of soft tissues,examining experimental methods,mechanical models,numerical simulations,and the progress in materials that mimic the mechanical performance of soft tissues.Finally,it reviews the damage and protection of human tissues under kinetic impacts,anticipating the future construction of soft tissue surrogate targets.The aim is to provide a systematic theoretical foundation and the latest advancements in the field,addressing the design,preparation,and quantitative modeling of biomimetic materials,thereby promoting the in-depth development of soft tissue mechanics and its applications.
文摘On May 9,2025 on the campus of the University of Science and Technology of China(USTC),Chinese Academy of Sciences(CAS),an exhibition was unveiled to celebrate the UN International Year of Quantum Science and Technology(IYQ)-a one-year-long worldwide event in memory of the founding of quantum mechanics(QM).
基金funded by the National Natural Science Foundation of China(No.12102244)the Open Fund of Hubei Longzhong Laboratory(No.2022KF-12)supported by the Laboratory of Flexible Electronics Technology at Tsinghua University.
文摘The development of wearable electronics necessitates flexible and robust energy storage components to enhance comfort and battery longevity.The key to flexible batteries is improving electrochemical stability during deformation,which demands mechanical analysis for optimized design and manufacturing.This paper summarizes the progress of flexible batteries from a mechanical perspective,highlighting highly deformable structures such as fiber,wave,origami,and rigid-supple integrated designs.We discuss mechanical performance characterization and existing evaluation criteria for battery flexibility,along with simulation modeling and testing methods.Furthermore,we analyze mechano-electrochemical coupling,reviewing theoretical models that simulate mechanical and electrochemical behavior under various loads and introduce coupling tests that assess electrochemical performance during deformation.Finally,we suggest future research directions to advance flexible energy storage devices.
基金Financial support of this work by the Technology Development program of China(Grant No.2022204B003)National Natural Science Foundation of China(12272083 and 12172078)the Fundamental Research Funds for the Central Universities(DUT24YJ136)is gratefully acknowledged.
文摘This paper presents a novel element differential method for modeling cracks in piezoelectric materials,aiming to simulate fracture behaviors and predict the fracture parameter known as the J-integral accurately.The method leverages an efficient collocation technique to satisfy traction and electric charge equilibrium on the crack surface,aligning internal nodes with piezoelectric governing equations without needing integration or variational principles.It combines the strengths of the strong form collocation and finite element methods.The J-integral is derived analytically using the equivalent domain integral method,employing Green's formula and Gauss's divergence theorem to transform line integrals into area integrals for solving two-dimensional piezoelectric material problems.The accuracy of the method is validated through comparison with three typical examples,and it offers fracture prevention strategies for engineering piezoelectric structures under different electrical loading patterns.
基金supported by Science Project of PetroChina Southwest Oil&Gas field Company,China(Grant.No:2024D112-01-02).
文摘Conventional geostress evaluation methods often assume static rock properties and neglect the dynamic degradation of mechanical parameters caused by damage evolution during drilling and fracturing processes,which significantly limits prediction accuracy.To address this gap,this study develops a multiphysics-coupled numerical framework integrating COMSOL Multiphysics and MATLAB,grounded in damage mechanics theory,to quantitatively investigate the control mechanism of progressive rock damage on geostress redistribution.By establishing a damage constitutive model coupled with thermo-hydro-mechanical interactions,we simulate the dynamic evolution of rock damage and its impact on stress field reorganization during wellbore operations.Key results demonstrate that(1)incorporating damage evolution leads to substantial deviations in both the magnitude and spatial distribution of geostress,with stress perturbations highly localized within damage zones;(2)changes in mechanical parameters-particularly elastic modulus and permeability-dominate stress adjustments,with heightened sensitivity in formations with low elastic moduli and high permeability;and(3)Poisson's ratio has a negligible influence,whereas permeability variation becomes critically important in low-stiffness formations.Field validation via leakage case analyses in the Wujiaping Formation confirms that the proposed method significantly enhances prediction accuracy compared with conventional approaches.This work elucidates the multiscale interdependency between damage and stress evolution by offering a physics-based framework to optimize drilling and stimulation design in heterogeneous reservoirs.
