Nowadays, the main communication object of Internet is human-human. But it is foreseeable that in the near future any object will have a unique identification and can be addressed and con- nected. The Internet will ex...Nowadays, the main communication object of Internet is human-human. But it is foreseeable that in the near future any object will have a unique identification and can be addressed and con- nected. The Internet will expand to the Internet of Things. IPv6 is the cornerstone of the Internet of Things. In this paper, we investigate a fast active worm, referred to as topological worm, which can propagate twice to more than three times faster tl^an a traditional scan-based worm. Topological worm spreads over AS-level network topology, making traditional epidemic models invalid for modeling the propagation of it. For this reason, we study topological worm propagation relying on simulations. First, we propose a new complex weighted network mod- el, which represents the real IPv6 AS-level network topology. And then, a new worm propagation model based on the weighted network model is constructed, which descries the topological worm propagation over AS-level network topology. The simulation results verify the topological worm model and demonstrate the effect of parameters on the propagation.展开更多
Trivial elastic waveguides induced by line defects and nontrivial elastic waveguides protected by topological edge states have been extensively examined in planar waveguide systems.Despite these investigations,little ...Trivial elastic waveguides induced by line defects and nontrivial elastic waveguides protected by topological edge states have been extensively examined in planar waveguide systems.Despite these investigations,little is known about topologically protected bulk states and their resulting robust transmission properties,especially in nonplanar elastic waveguides with folded,curved,and twisted surfaces.Elastic Dirac waveguides with robust boundary-induced bulk states are presented.These states arise from the truncated boundaries of bulks with linear Dirac conical dispersions,differing from topologically protected edge states ensured by the bulk-edge correspondence.Experimental proof is provided,in which boundary-induced bulk states show robustly high-throughput transmissions along the waveguides,even with folded,curved,and twisted surfaces.These results not only open up new avenues for examining novel topological phenomena about bulk but also offer new platforms for developing topological devices with nonplanar surfaces.展开更多
In electrochemical energy storage systems,the sodium-ion battery is typically integrated in the form of a“cell-module-cluster”,but its cross-scale thermal runaway triggering risk and the propagation mechanism remain...In electrochemical energy storage systems,the sodium-ion battery is typically integrated in the form of a“cell-module-cluster”,but its cross-scale thermal runaway triggering risk and the propagation mechanism remain unclear.This study reveals the cross-scale thermal runaway triggering and propagation behavior of sodium-ion batteries of“cell-module-cluster”under overcharge conditions,and investigates the effects of key factors,including module spacing,triggering cell location,and heat dissipation condition,on the thermal runaway propagation behavior.Results demonstrate that the thermal runaway propagation in a module containing the overcharged cell follows a sequential triggering mode,while thermal runaway in the downstream module exhibits a simultaneous triggering mode with greater severity.Furthermore,increasing the module spacing or enhancing the heat dissipation capacity can effectively reduce the heat accumulation and prevent the trigger of thermal runaway.On the above basis,the multi-dimensional evaluation strategy is proposed to quantitatively assess the hazard of sodium-ion battery cluster thermal runaway.The findings serve as a foundation for the safe design of sodium-ion batteries in energy storage systems.展开更多
As a pivotal environmental factor,light,comprising intensity,photoperiod,and spectrum,governs the entire life cycle of strawberries by mediating alterations in the plant’s morphological,physiological,and biochemical ...As a pivotal environmental factor,light,comprising intensity,photoperiod,and spectrum,governs the entire life cycle of strawberries by mediating alterations in the plant’s morphological,physiological,and biochemical traits.Although extensive research has been conducted on light-mediated growth regulation in horticultural crops,most reviews focus primarily on leafy and fruiting vegetables,with limited attention given to berry crops such as strawberries.Additionally,most existing reviews concentrate on one or several growth stages,failing to systematically characterize light’s effects throughout the entire growth cycle and postharvest stage.This review briefly summarizes the regulatory roles of light across key stages of strawberry growth,including seedling propagation,vegetative growth,reproductive growth,and postharvest stages.It seeks to address the knowledge gap by systematically organizing research findings across these developmental phases.The integrated analysis provides a theoretical foundation for designing stage-specific lighting strategies to improve strawberry yield and quality.展开更多
High-performance magnesium alloys are in great demand to meet the lightweight design requirements of aircraft.Grain size has long been recognized as a key factor influencing the mechanical properties of alloys.This st...High-performance magnesium alloys are in great demand to meet the lightweight design requirements of aircraft.Grain size has long been recognized as a key factor influencing the mechanical properties of alloys.This study investigates the effect of grain size,controlled by Zr addition,on the fatigue behavior of a recently developed low-cost Mg-2.6Nd-0.35Zn alloy,through systematic characterization and analysis of stress-life(S-N)curves,fatigue crack propagation,fracture surface morphology,stress intensity factor,and crack propagation threshold.The results show that after heat treatment(solution at 525±5℃ for 8 h and water quenching at 60-80℃,followed by aging at 250±5℃for 14 h and then air cooling),coarse-grained specimens(average grain size approximately 596μm)containing 0.12wt.%Zr exhibit greater resistance to fatigue crack propagation than fine-grained specimens(average grain size approximately 94μm)containing 0.46wt.%Zr.Coarse grains promote intergranular fracture,while fine grains favor transgranular fracture.In addition,coarse grains reduce the sensitivity of the crack tip to stress concentration.Furthermore,fine-grained samples demonstrate a longer total fatigue life,owing to their superior resistance to crack initiation,which significantly prolongs the crack initiation stage.These findings highlight the importance of optimizing grain size to achieve the best possible fatigue resistance in Mg-Nd-Zn-Zr alloys for practical engineering applications.展开更多
This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlyin...This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.展开更多
Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear stre...Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear strength.To further investigate this phenomenon,this study investigates the shear behaviour of rocks with different shear surface integrities under the influenceof different stress paths through laboratory tests and numerical simulations.The results indicate that the shear strength depends on the stress path and a decrease in the shear surface integrity reduces the degree of dependence.The cohesion and friction angle of the Mohr‒Coulomb criterion decrease with weakening of the shear surface integrity.For different stress paths,the direct shear strength is always greater than that of other shear stress paths.The pattern of changes in the acoustic emission count and cumulative count indirectly reflectsthe above findings.Numerical simulations further indicate that the different principal stress states and normal suppression effects during the shearing process lead to changes in the factors of crack propagation,resulting in different mechanical behaviours under various stress paths.For rocks with different integrity levels,the main reason for the different path dependences of shear strength is that the size of the area affected by shear is different.Shear failure will concentrate on the shear plane when the normal inhibition effect is greater.This study explores the mechanism of rock shear behaviour,providing a theoretical basis for establishing more accurate constitutive models and strength criteria.展开更多
We present a novel approach for calculating the energy budget components during the progressive failure process in cohesive-frictional geomaterials.The energy supplied through external loading can be either stored as ...We present a novel approach for calculating the energy budget components during the progressive failure process in cohesive-frictional geomaterials.The energy supplied through external loading can be either stored as elastic strain energy and plastic energy storage or dissipated through damage growth and irreversible plastic deformation mechanisms.Analytical functions describing energy budget components are derived based on a thermodynamic formulation in geomaterials fracture.The thermodynamically consistent derivation leads to a non-local ductile damage model,which is solved numerically in a non-linear finite element framework.The proposed model captures geomaterial fractures in three benchmark examples,including tensile and biaxial-compressive shear scenarios and slope stability analysis.The aspects of shear fracture propagation and energy budget mechanisms are elaborately investigated,considering different material properties and stochastic distributions.The numerical results are validated against existing experimental data and other analytical methods.The model provides a physics-based understanding of energy budget in geomaterials fracture,leading to advances in ground improvement and other geotechnical supporting systems.展开更多
Arc faults within the transformers can generate sudden pressure surges,constituting significant hazards that may precipitate oil tank explosions and severely compromise power system stability.Conventional power−freque...Arc faults within the transformers can generate sudden pressure surges,constituting significant hazards that may precipitate oil tank explosions and severely compromise power system stability.Conventional power−frequency arc discharge experiments encounter limitations in isolating pressure wave characteristics due to persistent gas generation and arc reignition.To circumvent these challenges,an oil-immersed impulse voltage discharge platform was conceived and engineered to investigate pressure wave propagation dynamics.A pressure numerical simulation model and theoretical model of oil−solid interface reflection and refraction were subsequently established to elucidate the pressure propagation mechanism.The experimental and simulation results show that the pressure wave generated by pulsed arc discharge in oil propagates radially in the form of spherical waves.Due to the viscous loss and wave front expansion of transformer oil,the peak pressure decays exponentially with distance,with a decay coefficientβ=1.15.When pressure waves encounter metal obstacles inside transformer oil,there are two propagation paths:direct transmission through and multiple reflections through,and a mode transformation of pressure waves occurs at the oil−solid interface,mainly propagating through obstacles in the form of transverse waves.This work quantitatively delineates the energy pressure wave coupling,propagation dynamics,and attenuation mechanisms,providing critical insights for assessing and mitigating arc fault-induced transformer explosion risks.展开更多
Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagati...Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagation behavior.To address the unclear mechanisms governing fracture penetration across coal-gangue interfaces,this study employs the Continuum-Discontinuum Element Method(CDEM)to simulate and analyze the vertical propagation of hydraulic fractures initiating within coal seams,based on geomechanical parameters derived from the deep Benxi Formation coal seams in the southeastern Ordos Basin.The investigation systematically examines the influence of geological and operational parameters on cross-interfacial fracture growth.Results demonstrate that vertical stress difference,elastic modulus contrast between coal and gangue layers,interfacial stress differential,and interfacial cohesion at coal-gangue interfaces are critical factors governing hydraulic fracture penetration through these interfaces.High vertical stress differences(>3 MPa)inhibit interfacial dilation,promoting predominant crosslayer fracture propagation.Reduced interfacial stress contrasts and enhanced interfacial cohesion facilitate fracture penetration across interfaces.Furthermore,smaller elastic modulus contrasts between coal and gangue correlate with increased interfacial aperture.Finally,lower injection rates effectively suppress vertical fracture propagation in deep coal reservoirs.This study elucidates the characteristics and mechanisms governing cross-layer fracture propagation in coal–rock composites with interbedded partings,and delineates the dynamic evolution laws and dominant controlling factors involved.Thefindings provide critical theoretical insights for the optimization of fracture design and the efficient development of deep coalbed methane reservoirs.展开更多
To enhance the mechanical reliability of dental prostheses under long-term service conditions,this study aimed to evaluate the fracture behavior and energy dissipation characteristics of three commonly used prosthetic...To enhance the mechanical reliability of dental prostheses under long-term service conditions,this study aimed to evaluate the fracture behavior and energy dissipation characteristics of three commonly used prosthetic materials,namely,zirconia ceramics(ZrO_(2)),cobalt-chromium alloy(Co-Cr),and titanium-zirconium alloy(Ti-13Zr),under various crack configurations.A three-dimensional finite element model of a single-crown prosthesis incorporating predefined cracks was established,and both axial and oblique multidirectional loads were applied.Using LS-DYNA software,the deformation patterns,principal stress distribution,and energy release characteristics during crack propagation were systematically analyzed.The experimental results indicate that Ti-13Zr alloy exhibited the highest crack resistance,making it particularly suitable for patients with insufficient bone volume or limited implant space.Co-Cr alloy demonstrated favorable structural stability and mechanical performance under high-load conditions.In contrast,due to its inherent brittleness,ZrO_(2)was more prone to rapid fracture propagation in long-span or high-stress scenarios,although it remains a preferred option for anterior esthetic zones and patients with metal sensitivities.Furthermore,the simulation outcomes were theoretically validated using Griffith's energy-based fracture criterion,reinforcing the accuracy of failure predictions based on principal stress analysis.This study elucidates the differences in clinical applicability among prosthetic materials and reveals their distinct fracture mechanisms,thereby providing a theoretical foundation for optimizing material selection and structural design.The findings contribute to improving the long-term safety and functional stability of implant-supported dental restorations.展开更多
Freezing and thawing processes play a crucial role in causing significant deformation and damage to layered soft rocks in cold region due to daily and seasonal temperature fluctuations.However,the frost heave mechanis...Freezing and thawing processes play a crucial role in causing significant deformation and damage to layered soft rocks in cold region due to daily and seasonal temperature fluctuations.However,the frost heave mechanism of the rocks and their mechanical behaviors at the meso-scale still require further investigations.For this,we focused on carbonaceous slate reported in a high-altitude cold region,in terms of mineral composition,content,and microstructure.The strength and failure of mineral grain(MG)interfaces are studied using three-point-bending tests,in order to explore the evolution of mode I fracture toughness and tensile strength with the Dugdale-Barenblatt model and the Weibull distribution model.The results indicate that the damage of slate involves the initiation and propagation of microfracture networks at clay MG interfaces(bedding planes),driven by frost heave pressure at macroscopic and microscopic scales.This process causes the detachment of some MGs,resulting in fracture surfaces with a distinctive pulled-off planar structure.The hydrophilicity of clay MGs,interfacial strengths,and microfracture structures contribute to the freeze-thaw damage.As the number of freeze-thaw cycles increases,the effective area per unit decreases,leading to an exponentially decreasing in mode I fracture toughness and tensile strength at MG interfaces.Approximately 67%strength degradation occurs after 14 freeze-thaw cycles.This provides theoretical basis and experimental methods for better understanding the damage and deterioration behaviors of layered soft rocks in cold region under natural freeze-thaw cycles.展开更多
The stability of rock slopes is frequently controlled by the initiation and propagation of inherent dominant cracks.This study systematically investigated these processes in valley slopes by combining fracture-mechani...The stability of rock slopes is frequently controlled by the initiation and propagation of inherent dominant cracks.This study systematically investigated these processes in valley slopes by combining fracture-mechanics analysis with transparent soil model tests.An analytical expression for the stress field at the dominant crack tip was derived from the slope stress distribution by superposing the corresponding stress intensity factors(SIFs).The theoretical predictions were then validated against observations from transparent soil model tests.The influences of slope angle(β),crack inclination angle(α),crack position parameter(b),and crack length parameter(h)on crack initiation and propagation were quantified.The results indicated that:(1)cracks at the slope crest tended to propagate in shear mode,and the shear crack initiation angle(θ_(s))was approximately 8°.Cracks at the slope toe might propagate in either tensile or shear mode.(2)θ_(s) at the slope crest increased withβ,b,and l,and decreased withα.The maximum change inθ_(s) induced by the considered parameters was approximately 30°.(3)The tensile crack initiation angle(θ_(t))at the slop toe decreased withβ,α,and l,while the influence of b was comparatively minor.The maximum change inθ_(t) caused by individual parameters ranged approximately from 25°to 60°.Predicted crack propagation modes and directions showed good agreement with experimental results.These findings provide theoretical guidance for stability assessments of valley slopes controlled by dominant crack propagation.展开更多
Shrublands and grasslands,which constitute approximately 70%of Australia’s vegetation,play a critical role in global wildfire-prone regions.To advance the understanding of grass fire spread,a three-dimensional,physic...Shrublands and grasslands,which constitute approximately 70%of Australia’s vegetation,play a critical role in global wildfire-prone regions.To advance the understanding of grass fire spread,a three-dimensional,physicsbased fire model provides valuable insights into fire dynamics.However,such models are computationally intensive and time-consuming.To address these challenges,we constructed an extensive numerical database comprising 64,000 high-fidelity wildfire simulation cases and implemented a Long Short-Term Memory neural network architecture.The model demonstrates strong predictive performance,achieving a coefficient of determination(R2)of 0.96 on training data,indicating excellent agreement with the physics-based simulation outputs.By utilizing coordinates from five reference points to predict fire front movement,this approach offers a novel method for analysing fire dynamics in homogeneous fuel beds with an average deviation of less than 2.5%.Combining the strengths of physics-based modelling and deep learning,our research enhances fire spread prediction accuracy of over 95%while significantly reducing computational demands.Future efforts will focus on refining the model,expanding the dataset,and incorporating additional variables to improve predictive capabilities and operational applicability.展开更多
The influence of different solution and aging conditions on the microstructure,impact toughness,and crack initiation and propagation mechanisms of the novel α+β titanium alloy Ti6422 was systematically investigated....The influence of different solution and aging conditions on the microstructure,impact toughness,and crack initiation and propagation mechanisms of the novel α+β titanium alloy Ti6422 was systematically investigated.By adjusting the furnace cooling time after solution treatment and the aging temperature,Ti6422 alloy samples were developed with a multi-level lamellar microstructure,in-cluding microscaleαcolonies and α_(p) lamellae,as well as nanoscale α_(s) phases.Extending the furnace cooling time after solution treatment at 920℃ for 1 h from 240 to 540 min,followed by aging at 600℃ for 6 h,increased the α_(p) lamella content,reduced the α_(s) phase content,expanded theαcolonies and α_(p) lamellae size,and improved the impact toughness from 22.7 to 53.8 J/cm^(2).Additionally,under the same solution treatment,raising the aging temperature from 500 to 700℃ resulted in a decrease in the α_(s) phase content and a growth in the thickness of the α_(p) lamella and α_(s) phase.The impact toughness increased significantly with these changes.Samples with high α_(p) lamellae content or large α_(s) phase size exhibited high crack initiation and propagation energies.Impact deformation caused severe kinking of the α_(p) lamellae in crack initiation and propagation areas,leading to a uniform and high-density kernel average misorientation(KAM)distribu-tion,enhancing plastic deformation coordination and uniformity.Moreover,the multidirectional arrangement of coarserαcolonies and α_(p) lamellae continuously deflect the crack propagation direction,inhibiting crack propagation.展开更多
This study investigates the effects of ocean boundaries on modal shapes in very-low-frequency(VLF,1–10 Hz)sound propagation through the deep ocean.Utilizing a normal mode solution formulated in terms of parabolic cyl...This study investigates the effects of ocean boundaries on modal shapes in very-low-frequency(VLF,1–10 Hz)sound propagation through the deep ocean.Utilizing a normal mode solution formulated in terms of parabolic cylinder functions(PCF),we demonstrate that boundary interactions induce a phase change reduction below-πat frequencies of several hertz.This reduction,in turn,forces a key transition in the solution,shifting the order of the PCF from integer to non-integer values.Analysis of the characteristic shape of the PCF versus its order reveals that these boundary-influenced modes exhibit an energy shift toward deeper regions and a weakened axial convergence of the underwater sound field.展开更多
We used hydrodynamic simulations and shock wave propagation theories to analyze the behavior of shock waves within Ti/Pt periodically modulated graded structures and their integration layers.The effects of the total n...We used hydrodynamic simulations and shock wave propagation theories to analyze the behavior of shock waves within Ti/Pt periodically modulated graded structures and their integration layers.The effects of the total number of periodic layers,the total thickness of graded materials and loading velocity on the integration layer thickness and behavior of pressure-strain rate were systematically investigated.The results reveal that,by adjusting the total number of periodically modulated layers,the total thickness of graded materials and loading velocity the pressure amplitudes of the reflected compressive and rarefaction waves at different interfaces of Ti/Pt periodically modulated graded materials can be precisely controlled.Furthermore,empirical structural design criteria for Ti/Pt periodically modulated graded materials are established.The thickness ratio variation between adjacent Ti/Pt layers in the periodic structure must exceed 0.32.After the collaborative design of the integration layer,Ti/Pt periodically modulated graded materials can achieve a controllable loading function with pressures ranging from 1.4 to 144 GPa and strain rates from 3.8×10^(4) to 1.7×10^(7) s^(–1).The outcomes of this research provide a theoretical and simulation basis for the optimized design of periodically modulated graded materials to be utilized in ramp compression experiments.展开更多
Optical non-reciprocity is a fundamental phenomenon in photonics.It is crucial for developing devices that rely on directional signal control,such as optical isolators and circulators.However,most research in this fie...Optical non-reciprocity is a fundamental phenomenon in photonics.It is crucial for developing devices that rely on directional signal control,such as optical isolators and circulators.However,most research in this field has focused on systems in equilibrium or steady states.In this work,we demonstrate a room-temperature Rydberg atomic platform where the unidirectional propagation of light acts as a switch to mediate time-crystalline-like collective oscillations through atomic synchronization.展开更多
Deep shale gas reservoirs in the southern Sichuan Basin are typically characterized by significant horizontal stress anisotropy(expressed as stress difference),variable brittleness-ductility in rock mechanics,and stro...Deep shale gas reservoirs in the southern Sichuan Basin are typically characterized by significant horizontal stress anisotropy(expressed as stress difference),variable brittleness-ductility in rock mechanics,and strong heterogeneity.These complex geomechanical conditions lead to pronounced differences in hydraulic fracturing outcomes among wells and sections.To investigate hydraulic fracture propagation and fracturing fluid injection behavior under varying geomechanical settings,true triaxial physical simulation tests were performed on 400×400×400 mm artificial rock samples.The samples were designed with different media properties based on similarity criteria.A sensitivity analysis was conducted to assess the effects of brittleness-ductility characteristics,natural fractures,and in-situ stress conditions.The results reveal that:(i)brittle samples with lower stress difference are favorable for forming complex,perforable fracture networks;(ii)brittle samples with higher stress difference tend to develop simple,planar hydraulic fractures,with natural fractures only slightly activated during very short injection periods;(iii)ductile behavior enhances the activation of natural fractures but reduces fracture complexity compared with brittle samples,even under lower stress difference;and(iv)for typical deep shale formations,larger fluid injection volumes combined with high-density,multi-cluster fracturing techniques are recommended.展开更多
Hydraulic stimulation technology is widely employed to enhance the permeability of geothermal reservoirs.Nevertheless,accurately predicting hydraulic fracture propagation in complex geological conditions remains chall...Hydraulic stimulation technology is widely employed to enhance the permeability of geothermal reservoirs.Nevertheless,accurately predicting hydraulic fracture propagation in complex geological conditions remains challenging,thereby hindering the effective utilization of existing natural fractures.In this study,a phase field model was developed utilizing the finite element method to examine the influence of fluid presence,stress conditions,and natural fractures on the initiation and propagation of hydraulic fractures.The model employs Biot's poroelasticity theory to establish the coupling between the displacement field and the fluid field,while the phase field theory is applied to simulate fracture behavior.The results show that whenσ_(x0)/σ_(y0)<3 or qf<20 kg/(m^(3)·s),the presence of natural fractures can alter the original propagation direction of hydraulic fractures.Conversely,in the absence of these conditions,the propagation path of natural fractures is predominantly influenced by the initial stress field.Furthermore,based on the analysis of breakdown pressure and damage area,the optimal intersection angle between natural fractures and hydraulic fractures is determined to range from 45°to 60°.Finally,once a dominant channel forms,initiating and propagating hydraulic fractures in other directions becomes increasingly difficult,even in highly fractured areas.This method tackles the challenges of initiating and propagating hydraulic fractures in complex geological conditions,providing a theoretical basis for optimizing Enhanced Geothermal System(EGS)projects.展开更多
基金supported by the Ministry of Education Research Project for Returned Talents after Studying Abroadthe Ministry of Education Project of Science and Technology Basic Resource Data Platform(No.507001)+1 种基金International Scientific and Technological Cooperation Program(S2010GR0902)Chinese Universities Scientific Fund(2009RC0502)
文摘Nowadays, the main communication object of Internet is human-human. But it is foreseeable that in the near future any object will have a unique identification and can be addressed and con- nected. The Internet will expand to the Internet of Things. IPv6 is the cornerstone of the Internet of Things. In this paper, we investigate a fast active worm, referred to as topological worm, which can propagate twice to more than three times faster tl^an a traditional scan-based worm. Topological worm spreads over AS-level network topology, making traditional epidemic models invalid for modeling the propagation of it. For this reason, we study topological worm propagation relying on simulations. First, we propose a new complex weighted network mod- el, which represents the real IPv6 AS-level network topology. And then, a new worm propagation model based on the weighted network model is constructed, which descries the topological worm propagation over AS-level network topology. The simulation results verify the topological worm model and demonstrate the effect of parameters on the propagation.
基金supported by the National Natural Science Foundation of China(Grant No.12072108)the Natural Science Foundation of Hunan Province for Distinguished Young Scholars(Grant No.2022JJ10003)。
文摘Trivial elastic waveguides induced by line defects and nontrivial elastic waveguides protected by topological edge states have been extensively examined in planar waveguide systems.Despite these investigations,little is known about topologically protected bulk states and their resulting robust transmission properties,especially in nonplanar elastic waveguides with folded,curved,and twisted surfaces.Elastic Dirac waveguides with robust boundary-induced bulk states are presented.These states arise from the truncated boundaries of bulks with linear Dirac conical dispersions,differing from topologically protected edge states ensured by the bulk-edge correspondence.Experimental proof is provided,in which boundary-induced bulk states show robustly high-throughput transmissions along the waveguides,even with folded,curved,and twisted surfaces.These results not only open up new avenues for examining novel topological phenomena about bulk but also offer new platforms for developing topological devices with nonplanar surfaces.
基金supported by the Anhui Quality Infrastructure Standardization Project(Grant No.2024MKSO7)the Science and Technology Project of State Grid(SGAHDK00DJJS2310027)the Anhui Provincial Natural Science Foundation(Grant No.2208085UD03).
文摘In electrochemical energy storage systems,the sodium-ion battery is typically integrated in the form of a“cell-module-cluster”,but its cross-scale thermal runaway triggering risk and the propagation mechanism remain unclear.This study reveals the cross-scale thermal runaway triggering and propagation behavior of sodium-ion batteries of“cell-module-cluster”under overcharge conditions,and investigates the effects of key factors,including module spacing,triggering cell location,and heat dissipation condition,on the thermal runaway propagation behavior.Results demonstrate that the thermal runaway propagation in a module containing the overcharged cell follows a sequential triggering mode,while thermal runaway in the downstream module exhibits a simultaneous triggering mode with greater severity.Furthermore,increasing the module spacing or enhancing the heat dissipation capacity can effectively reduce the heat accumulation and prevent the trigger of thermal runaway.On the above basis,the multi-dimensional evaluation strategy is proposed to quantitatively assess the hazard of sodium-ion battery cluster thermal runaway.The findings serve as a foundation for the safe design of sodium-ion batteries in energy storage systems.
基金supported by National Key Research and Development Program of China(2023YFF1001700)the Unveiling and Leading Projects(2022kj05)+1 种基金Yafu Technology Innovation Team of Jiangsu Vocational College of Agriculture and Forestry(2024kj02)the Innovation&Entrepreneurship Training Program for College Students of Qingdao Agricultural University(QNDC20250149).
文摘As a pivotal environmental factor,light,comprising intensity,photoperiod,and spectrum,governs the entire life cycle of strawberries by mediating alterations in the plant’s morphological,physiological,and biochemical traits.Although extensive research has been conducted on light-mediated growth regulation in horticultural crops,most reviews focus primarily on leafy and fruiting vegetables,with limited attention given to berry crops such as strawberries.Additionally,most existing reviews concentrate on one or several growth stages,failing to systematically characterize light’s effects throughout the entire growth cycle and postharvest stage.This review briefly summarizes the regulatory roles of light across key stages of strawberry growth,including seedling propagation,vegetative growth,reproductive growth,and postharvest stages.It seeks to address the knowledge gap by systematically organizing research findings across these developmental phases.The integrated analysis provides a theoretical foundation for designing stage-specific lighting strategies to improve strawberry yield and quality.
文摘High-performance magnesium alloys are in great demand to meet the lightweight design requirements of aircraft.Grain size has long been recognized as a key factor influencing the mechanical properties of alloys.This study investigates the effect of grain size,controlled by Zr addition,on the fatigue behavior of a recently developed low-cost Mg-2.6Nd-0.35Zn alloy,through systematic characterization and analysis of stress-life(S-N)curves,fatigue crack propagation,fracture surface morphology,stress intensity factor,and crack propagation threshold.The results show that after heat treatment(solution at 525±5℃ for 8 h and water quenching at 60-80℃,followed by aging at 250±5℃for 14 h and then air cooling),coarse-grained specimens(average grain size approximately 596μm)containing 0.12wt.%Zr exhibit greater resistance to fatigue crack propagation than fine-grained specimens(average grain size approximately 94μm)containing 0.46wt.%Zr.Coarse grains promote intergranular fracture,while fine grains favor transgranular fracture.In addition,coarse grains reduce the sensitivity of the crack tip to stress concentration.Furthermore,fine-grained samples demonstrate a longer total fatigue life,owing to their superior resistance to crack initiation,which significantly prolongs the crack initiation stage.These findings highlight the importance of optimizing grain size to achieve the best possible fatigue resistance in Mg-Nd-Zn-Zr alloys for practical engineering applications.
基金supported by the National Natural Science Foundation of China(Grant No.42261134532,42405059,and U2342212)。
文摘This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.
基金support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX24_2822)the Graduate Innovation Program of China University of Mining and Technology(Grant No.2024WLKXJ205)the National Natural Science Foundation of China(Grant No.52474157).
文摘Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear strength.To further investigate this phenomenon,this study investigates the shear behaviour of rocks with different shear surface integrities under the influenceof different stress paths through laboratory tests and numerical simulations.The results indicate that the shear strength depends on the stress path and a decrease in the shear surface integrity reduces the degree of dependence.The cohesion and friction angle of the Mohr‒Coulomb criterion decrease with weakening of the shear surface integrity.For different stress paths,the direct shear strength is always greater than that of other shear stress paths.The pattern of changes in the acoustic emission count and cumulative count indirectly reflectsthe above findings.Numerical simulations further indicate that the different principal stress states and normal suppression effects during the shearing process lead to changes in the factors of crack propagation,resulting in different mechanical behaviours under various stress paths.For rocks with different integrity levels,the main reason for the different path dependences of shear strength is that the size of the area affected by shear is different.Shear failure will concentrate on the shear plane when the normal inhibition effect is greater.This study explores the mechanism of rock shear behaviour,providing a theoretical basis for establishing more accurate constitutive models and strength criteria.
基金supported by the National Natural Science Foundation of China(Grant No.52179128)the Sand Hazards and Opportunities for Resilience,Energy,and Sustainability(SHORES)Center,funded by Tamkeen under the NYUAD Research Institute Award CG013.
文摘We present a novel approach for calculating the energy budget components during the progressive failure process in cohesive-frictional geomaterials.The energy supplied through external loading can be either stored as elastic strain energy and plastic energy storage or dissipated through damage growth and irreversible plastic deformation mechanisms.Analytical functions describing energy budget components are derived based on a thermodynamic formulation in geomaterials fracture.The thermodynamically consistent derivation leads to a non-local ductile damage model,which is solved numerically in a non-linear finite element framework.The proposed model captures geomaterial fractures in three benchmark examples,including tensile and biaxial-compressive shear scenarios and slope stability analysis.The aspects of shear fracture propagation and energy budget mechanisms are elaborately investigated,considering different material properties and stochastic distributions.The numerical results are validated against existing experimental data and other analytical methods.The model provides a physics-based understanding of energy budget in geomaterials fracture,leading to advances in ground improvement and other geotechnical supporting systems.
基金funded by the Science and Technology Program of State Grid Corporation of China(5500-202356358A-2-1-ZX).
文摘Arc faults within the transformers can generate sudden pressure surges,constituting significant hazards that may precipitate oil tank explosions and severely compromise power system stability.Conventional power−frequency arc discharge experiments encounter limitations in isolating pressure wave characteristics due to persistent gas generation and arc reignition.To circumvent these challenges,an oil-immersed impulse voltage discharge platform was conceived and engineered to investigate pressure wave propagation dynamics.A pressure numerical simulation model and theoretical model of oil−solid interface reflection and refraction were subsequently established to elucidate the pressure propagation mechanism.The experimental and simulation results show that the pressure wave generated by pulsed arc discharge in oil propagates radially in the form of spherical waves.Due to the viscous loss and wave front expansion of transformer oil,the peak pressure decays exponentially with distance,with a decay coefficientβ=1.15.When pressure waves encounter metal obstacles inside transformer oil,there are two propagation paths:direct transmission through and multiple reflections through,and a mode transformation of pressure waves occurs at the oil−solid interface,mainly propagating through obstacles in the form of transverse waves.This work quantitatively delineates the energy pressure wave coupling,propagation dynamics,and attenuation mechanisms,providing critical insights for assessing and mitigating arc fault-induced transformer explosion risks.
文摘Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagation behavior.To address the unclear mechanisms governing fracture penetration across coal-gangue interfaces,this study employs the Continuum-Discontinuum Element Method(CDEM)to simulate and analyze the vertical propagation of hydraulic fractures initiating within coal seams,based on geomechanical parameters derived from the deep Benxi Formation coal seams in the southeastern Ordos Basin.The investigation systematically examines the influence of geological and operational parameters on cross-interfacial fracture growth.Results demonstrate that vertical stress difference,elastic modulus contrast between coal and gangue layers,interfacial stress differential,and interfacial cohesion at coal-gangue interfaces are critical factors governing hydraulic fracture penetration through these interfaces.High vertical stress differences(>3 MPa)inhibit interfacial dilation,promoting predominant crosslayer fracture propagation.Reduced interfacial stress contrasts and enhanced interfacial cohesion facilitate fracture penetration across interfaces.Furthermore,smaller elastic modulus contrasts between coal and gangue correlate with increased interfacial aperture.Finally,lower injection rates effectively suppress vertical fracture propagation in deep coal reservoirs.This study elucidates the characteristics and mechanisms governing cross-layer fracture propagation in coal–rock composites with interbedded partings,and delineates the dynamic evolution laws and dominant controlling factors involved.Thefindings provide critical theoretical insights for the optimization of fracture design and the efficient development of deep coalbed methane reservoirs.
基金Funded by the National Key R&D Program of China(No.2023YFC2412300)the Technology Development Project of Shan-dong Weigao Orthopedic Materials Co.,Ltd.(No.20221h0074)the Independent Innovation Research Fund of Wuhan University of Technology(No.104972024ZHZXhp0027)。
文摘To enhance the mechanical reliability of dental prostheses under long-term service conditions,this study aimed to evaluate the fracture behavior and energy dissipation characteristics of three commonly used prosthetic materials,namely,zirconia ceramics(ZrO_(2)),cobalt-chromium alloy(Co-Cr),and titanium-zirconium alloy(Ti-13Zr),under various crack configurations.A three-dimensional finite element model of a single-crown prosthesis incorporating predefined cracks was established,and both axial and oblique multidirectional loads were applied.Using LS-DYNA software,the deformation patterns,principal stress distribution,and energy release characteristics during crack propagation were systematically analyzed.The experimental results indicate that Ti-13Zr alloy exhibited the highest crack resistance,making it particularly suitable for patients with insufficient bone volume or limited implant space.Co-Cr alloy demonstrated favorable structural stability and mechanical performance under high-load conditions.In contrast,due to its inherent brittleness,ZrO_(2)was more prone to rapid fracture propagation in long-span or high-stress scenarios,although it remains a preferred option for anterior esthetic zones and patients with metal sensitivities.Furthermore,the simulation outcomes were theoretically validated using Griffith's energy-based fracture criterion,reinforcing the accuracy of failure predictions based on principal stress analysis.This study elucidates the differences in clinical applicability among prosthetic materials and reveals their distinct fracture mechanisms,thereby providing a theoretical foundation for optimizing material selection and structural design.The findings contribute to improving the long-term safety and functional stability of implant-supported dental restorations.
基金support of National Natural Science Foundation of China(Grant No.U24A20184)Science and Technology Planning Project of Xizang Autonomous Region,China(Grant Nos.XZ202201ZY0021G,XZ202401ZY0085).
文摘Freezing and thawing processes play a crucial role in causing significant deformation and damage to layered soft rocks in cold region due to daily and seasonal temperature fluctuations.However,the frost heave mechanism of the rocks and their mechanical behaviors at the meso-scale still require further investigations.For this,we focused on carbonaceous slate reported in a high-altitude cold region,in terms of mineral composition,content,and microstructure.The strength and failure of mineral grain(MG)interfaces are studied using three-point-bending tests,in order to explore the evolution of mode I fracture toughness and tensile strength with the Dugdale-Barenblatt model and the Weibull distribution model.The results indicate that the damage of slate involves the initiation and propagation of microfracture networks at clay MG interfaces(bedding planes),driven by frost heave pressure at macroscopic and microscopic scales.This process causes the detachment of some MGs,resulting in fracture surfaces with a distinctive pulled-off planar structure.The hydrophilicity of clay MGs,interfacial strengths,and microfracture structures contribute to the freeze-thaw damage.As the number of freeze-thaw cycles increases,the effective area per unit decreases,leading to an exponentially decreasing in mode I fracture toughness and tensile strength at MG interfaces.Approximately 67%strength degradation occurs after 14 freeze-thaw cycles.This provides theoretical basis and experimental methods for better understanding the damage and deterioration behaviors of layered soft rocks in cold region under natural freeze-thaw cycles.
基金financially supported by the National Nature Science Foundation of China(Nos.52379110 and 42207222)the Key Technologies for Accurate Diagnosis and Intelligent Prevention and Control of Slope Hazards in Open Pit Mines,181 Major R&D projects of Metallurgical Corporation of China Ltd。
文摘The stability of rock slopes is frequently controlled by the initiation and propagation of inherent dominant cracks.This study systematically investigated these processes in valley slopes by combining fracture-mechanics analysis with transparent soil model tests.An analytical expression for the stress field at the dominant crack tip was derived from the slope stress distribution by superposing the corresponding stress intensity factors(SIFs).The theoretical predictions were then validated against observations from transparent soil model tests.The influences of slope angle(β),crack inclination angle(α),crack position parameter(b),and crack length parameter(h)on crack initiation and propagation were quantified.The results indicated that:(1)cracks at the slope crest tended to propagate in shear mode,and the shear crack initiation angle(θ_(s))was approximately 8°.Cracks at the slope toe might propagate in either tensile or shear mode.(2)θ_(s) at the slope crest increased withβ,b,and l,and decreased withα.The maximum change inθ_(s) induced by the considered parameters was approximately 30°.(3)The tensile crack initiation angle(θ_(t))at the slop toe decreased withβ,α,and l,while the influence of b was comparatively minor.The maximum change inθ_(t) caused by individual parameters ranged approximately from 25°to 60°.Predicted crack propagation modes and directions showed good agreement with experimental results.These findings provide theoretical guidance for stability assessments of valley slopes controlled by dominant crack propagation.
基金funded by the National Natural Science Foundation of China(NSFC No.52322610)Hong Kong Research Grants Council Theme-based Research Scheme(T22-505/19-N)Furthermore,this research was undertaken with the assistance of computational resources from the National Computational Infrastructure(NCI Australia),an NCRISenabled capability supported by the Australian Government.
文摘Shrublands and grasslands,which constitute approximately 70%of Australia’s vegetation,play a critical role in global wildfire-prone regions.To advance the understanding of grass fire spread,a three-dimensional,physicsbased fire model provides valuable insights into fire dynamics.However,such models are computationally intensive and time-consuming.To address these challenges,we constructed an extensive numerical database comprising 64,000 high-fidelity wildfire simulation cases and implemented a Long Short-Term Memory neural network architecture.The model demonstrates strong predictive performance,achieving a coefficient of determination(R2)of 0.96 on training data,indicating excellent agreement with the physics-based simulation outputs.By utilizing coordinates from five reference points to predict fire front movement,this approach offers a novel method for analysing fire dynamics in homogeneous fuel beds with an average deviation of less than 2.5%.Combining the strengths of physics-based modelling and deep learning,our research enhances fire spread prediction accuracy of over 95%while significantly reducing computational demands.Future efforts will focus on refining the model,expanding the dataset,and incorporating additional variables to improve predictive capabilities and operational applicability.
基金supported by the National Natural Science Foundation of China(No.52090041).
文摘The influence of different solution and aging conditions on the microstructure,impact toughness,and crack initiation and propagation mechanisms of the novel α+β titanium alloy Ti6422 was systematically investigated.By adjusting the furnace cooling time after solution treatment and the aging temperature,Ti6422 alloy samples were developed with a multi-level lamellar microstructure,in-cluding microscaleαcolonies and α_(p) lamellae,as well as nanoscale α_(s) phases.Extending the furnace cooling time after solution treatment at 920℃ for 1 h from 240 to 540 min,followed by aging at 600℃ for 6 h,increased the α_(p) lamella content,reduced the α_(s) phase content,expanded theαcolonies and α_(p) lamellae size,and improved the impact toughness from 22.7 to 53.8 J/cm^(2).Additionally,under the same solution treatment,raising the aging temperature from 500 to 700℃ resulted in a decrease in the α_(s) phase content and a growth in the thickness of the α_(p) lamella and α_(s) phase.The impact toughness increased significantly with these changes.Samples with high α_(p) lamellae content or large α_(s) phase size exhibited high crack initiation and propagation energies.Impact deformation caused severe kinking of the α_(p) lamellae in crack initiation and propagation areas,leading to a uniform and high-density kernel average misorientation(KAM)distribu-tion,enhancing plastic deformation coordination and uniformity.Moreover,the multidirectional arrangement of coarserαcolonies and α_(p) lamellae continuously deflect the crack propagation direction,inhibiting crack propagation.
基金Project supported by the National Natural Science Foundation of China(Grant No.12204128)。
文摘This study investigates the effects of ocean boundaries on modal shapes in very-low-frequency(VLF,1–10 Hz)sound propagation through the deep ocean.Utilizing a normal mode solution formulated in terms of parabolic cylinder functions(PCF),we demonstrate that boundary interactions induce a phase change reduction below-πat frequencies of several hertz.This reduction,in turn,forces a key transition in the solution,shifting the order of the PCF from integer to non-integer values.Analysis of the characteristic shape of the PCF versus its order reveals that these boundary-influenced modes exhibit an energy shift toward deeper regions and a weakened axial convergence of the underwater sound field.
基金Funded by the Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030001)the Foundation of National Key Laboratory of Shock Wave and Detonation Physics(No.JCKYS2022212004)。
文摘We used hydrodynamic simulations and shock wave propagation theories to analyze the behavior of shock waves within Ti/Pt periodically modulated graded structures and their integration layers.The effects of the total number of periodic layers,the total thickness of graded materials and loading velocity on the integration layer thickness and behavior of pressure-strain rate were systematically investigated.The results reveal that,by adjusting the total number of periodically modulated layers,the total thickness of graded materials and loading velocity the pressure amplitudes of the reflected compressive and rarefaction waves at different interfaces of Ti/Pt periodically modulated graded materials can be precisely controlled.Furthermore,empirical structural design criteria for Ti/Pt periodically modulated graded materials are established.The thickness ratio variation between adjacent Ti/Pt layers in the periodic structure must exceed 0.32.After the collaborative design of the integration layer,Ti/Pt periodically modulated graded materials can achieve a controllable loading function with pressures ranging from 1.4 to 144 GPa and strain rates from 3.8×10^(4) to 1.7×10^(7) s^(–1).The outcomes of this research provide a theoretical and simulation basis for the optimized design of periodically modulated graded materials to be utilized in ramp compression experiments.
基金supported by the National Natural Science Foundation of China (Grant No.12274131)the Innovation Program for Quantum Science and Technology (Grant No.2024ZD0300101)。
文摘Optical non-reciprocity is a fundamental phenomenon in photonics.It is crucial for developing devices that rely on directional signal control,such as optical isolators and circulators.However,most research in this field has focused on systems in equilibrium or steady states.In this work,we demonstrate a room-temperature Rydberg atomic platform where the unidirectional propagation of light acts as a switch to mediate time-crystalline-like collective oscillations through atomic synchronization.
基金the National Natural Science Foundation of China(Nos.52204005,52192622,U20A20265)the Sichuan Science Fund for Young Scholars(23NSFSC4652).
文摘Deep shale gas reservoirs in the southern Sichuan Basin are typically characterized by significant horizontal stress anisotropy(expressed as stress difference),variable brittleness-ductility in rock mechanics,and strong heterogeneity.These complex geomechanical conditions lead to pronounced differences in hydraulic fracturing outcomes among wells and sections.To investigate hydraulic fracture propagation and fracturing fluid injection behavior under varying geomechanical settings,true triaxial physical simulation tests were performed on 400×400×400 mm artificial rock samples.The samples were designed with different media properties based on similarity criteria.A sensitivity analysis was conducted to assess the effects of brittleness-ductility characteristics,natural fractures,and in-situ stress conditions.The results reveal that:(i)brittle samples with lower stress difference are favorable for forming complex,perforable fracture networks;(ii)brittle samples with higher stress difference tend to develop simple,planar hydraulic fractures,with natural fractures only slightly activated during very short injection periods;(iii)ductile behavior enhances the activation of natural fractures but reduces fracture complexity compared with brittle samples,even under lower stress difference;and(iv)for typical deep shale formations,larger fluid injection volumes combined with high-density,multi-cluster fracturing techniques are recommended.
基金supported by the National Key Research and Development Program(2021YFB150740401)National Natural Science Foundation of China(42202336)the CAS Pioneer Hundred Talents Program in China(Y826031C01)。
文摘Hydraulic stimulation technology is widely employed to enhance the permeability of geothermal reservoirs.Nevertheless,accurately predicting hydraulic fracture propagation in complex geological conditions remains challenging,thereby hindering the effective utilization of existing natural fractures.In this study,a phase field model was developed utilizing the finite element method to examine the influence of fluid presence,stress conditions,and natural fractures on the initiation and propagation of hydraulic fractures.The model employs Biot's poroelasticity theory to establish the coupling between the displacement field and the fluid field,while the phase field theory is applied to simulate fracture behavior.The results show that whenσ_(x0)/σ_(y0)<3 or qf<20 kg/(m^(3)·s),the presence of natural fractures can alter the original propagation direction of hydraulic fractures.Conversely,in the absence of these conditions,the propagation path of natural fractures is predominantly influenced by the initial stress field.Furthermore,based on the analysis of breakdown pressure and damage area,the optimal intersection angle between natural fractures and hydraulic fractures is determined to range from 45°to 60°.Finally,once a dominant channel forms,initiating and propagating hydraulic fractures in other directions becomes increasingly difficult,even in highly fractured areas.This method tackles the challenges of initiating and propagating hydraulic fractures in complex geological conditions,providing a theoretical basis for optimizing Enhanced Geothermal System(EGS)projects.
