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Measuring ice lens initiation in soils by particle image velocimetry 认领 引用 被引量：1
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作者 Jinfeng Li Jidong Teng +3 位作者 Haosong He Wenzhang Xu Jenisha Singh Sheng Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第1期761-771,共11页
Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dime... Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dimensional freezing tests is designed using the particle image velocimetry(PIV)method to monitor the frost heave and ice lens formation.The results show that the conventional parameters,such as displacement and velocity,cannot be used to track the ice lens formation,while the strain can be employed to detect the ice lens formation and investigate the freezing change patterns.This study proposes strain as a new criterion for assessing ice lens initiation,applicable across various soil types and freezing conditions(constant freezing and ramped freezing).The strain change in the region where the ice lens forms is the largest during the freezing process.Additionally,strain curves at the top of the soil samples can reveal different freezing patterns and distinguish the first and second frost heave stages.This newly developed technology enables continuous,non-destructive monitoring of ice lens initiation across diverse conditions and soil types,enhancing data visualization and three-dimensional modeling of freezing parameters while improving traditional methods by directly measuring velocity and strain in frost heave investigations.The study is expected to enhance the research of ice lens criterion and provide a new perspective for monitoring the freezing process. 展开更多
关键词 Frost heave Ice lens initiation Particle image velocimetry(PIV) Strain
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Convection Initiation over Mountain Slopes in North China:Roles of Upslope Winds and Orographic Waves 认领 引用
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作者 Hongpei YANG Yu DU +1 位作者 Zijian CHEN Xiaoyu GAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2026年第5期889-906,共18页
Using high-resolution observations,mesoscale simulations,and idealized experiments,this study investigates the mechanisms governing an episode of orographic convection initiation(CI)during the North China Heavy Rainfa... Using high-resolution observations,mesoscale simulations,and idealized experiments,this study investigates the mechanisms governing an episode of orographic convection initiation(CI)during the North China Heavy Rainfall Experiment.On 4 August 2024,repeated CI occurred over the eastern slopes of the Taihang Mountains in the late afternoon,subsequently enhancing an upstream downhill convective storm.Wind profiler radar data and dense automatic weather stations reveal that CI was supported by strengthening southeasterly upslope winds.These winds primarily resulted from the migration of the mountain-plain solenoid and the mountainward-propagating outflow from a convective cold pool over the plain,with sensitivity experiments showing the latter contributed roughly 22%of the wind strength.The upslope flows gradually transported unstable air from the plain to the slope,fostering CI.Mesoscale simulations further highlight the key role of orographic waves near the mountain ridge,which generated strong downslope winds.The near-surface convergence between downslope and upslope flows,combined with wave-induced divergence aloft,produced deep ascent over the slope.Removing mountain ridges weakened wave strength and reduced downslope wind speeds by~8 m s-1.Without orographic heating in the idealized simulation(i.e.,no mountain-plain solenoid),only strong wave descent occurred below 2km,inhibiting CI.These findings underscore the critical interplay among plain convection,orographic waves,and the mountain-plain solenoid,offering new insight into the processes controlling orographic CI in North China. 展开更多
关键词 convection initiation mountain-plain solenoid orographic waves cold pools topographic convection
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Theoretical investigation on the initiation and propagation behavior of dominant cracks in valley slopes 认领 引用
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作者 Xianlun Leng Chuan Wang +4 位作者 Chengtang Wang Zhanrong Zhang Haibin Wang Lan Cui Kun Fang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2026年第1期95-112,共18页
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(θs)was approximately 8°.Cracks at the slope toe might propagate in either tensile or shear mode.(2)θs at the slope crest increased withβ,b,and l,and decreased withα.The maximum change inθs induced by the considered parameters was approximately 30°.(3)The tensile crack initiation angle(θt)at the slop toe decreased withβ,α,and l,while the influence of b was comparatively minor.The maximum change inθt 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
关键词 Valley rock slope Crack initiation angle Crack propagation mode Stress field formula Fracture mechanics
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Investigation on the rolling contact fatigue cracks initiation of subway fixed frogs based on transient dynamics 认领 引用
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作者 Zhaoguang Zheng Zhiguo Dong +3 位作者 Jiayi Hu Jingmang Xu Kai Wang Ping Wang 《Railway Engineering Science》 EI 2026年第2期275-293,共19页
The issue of fatigue damage to rails has become increasingly prominent with the rise in subway traffic and speed.The hazardous space of the turnout frog significantly intensifies the dynamic interaction between the ve... The issue of fatigue damage to rails has become increasingly prominent with the rise in subway traffic and speed.The hazardous space of the turnout frog significantly intensifies the dynamic interaction between the vehicle and the frog rail,leading to more pronounced fatigue damage in the turnout rail.This paper focuses on the No.9 turnout fixed frog commonly used in subway lines.A three-dimensional explicit transient rolling contact finite element model of the fixed frog is established.The dynamic response of wheel-rail rolling contact is analyzed under various speeds and vertical stiffness conditions.Rolling contact fatigue crack locations,angles,and initiation life were investigated.The research indicates that the 30 mm top width cross-section of the nose rail is most susceptible to fatigue cracks,which initiate on the rail surface.The angle between the crack initiation surface and the lateral direction is between 70°and 95°.Higher speeds result in shorter fatigue life,while the vertical stiffness of the fastener has less of an effect.The simulation results align with findings from field surveys.The established model and research conclusions can provide theoretical support for optimizing fixed frog structures and predicting fatigue life. 展开更多
关键词 Fixed frog Rolling contact fatigue Crack initiation Explicit finite element method Vehicle speed Fastener stiffness
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Smoking Prevalence and Initiation Reasons Among College Students—China,2025 认领 引用
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作者 Mingxin Qi Xinying Zeng +2 位作者 Shiwei Liu Ying Liu Lin Xiao 《China CDC weekly》 SCIE CSCD 2026年第22期673-678,共6页
Introduction:College students represent a key population at risk for smoking initiation and continued use.During the transition from high school to college,increased autonomy and legal access to tobacco may elevate sm... Introduction:College students represent a key population at risk for smoking initiation and continued use.During the transition from high school to college,increased autonomy and legal access to tobacco may elevate smoking prevalence,yet tobacco control policies specifically targeting this group remain limited.Methods:This study analyzed smoking prevalence[with 95%confidence intervals(CIs)]and reasons for smoking initiation among college students using data from the 2025 national survey.Survey-weighted prevalence estimates were calculated using complex sampling procedures,and Rao-Scottχ2 tests were applied to assess differences across subgroups.Results:In 2025,the prevalence of current and daily smoking among Chinese college students was 7.3%(95%CI:6.7%,7.9%)and 4.8%(95%CI:4.4%,5.2%),respectively,with males substantially exceeding females[current smoking:males 12.9%(95%CI:12.0%,13.8%),females 1.4%(95%CI:1.3%,1.5%);daily smoking:males 8.7%(95%CI:8.1%,9.4%),females 0.7%(95%CI:0.6%,0.8%)].Higher Vocational Colleges had higher rates[current smoking:10.0%(95%CI:8.9%,11.1%),daily smoking:6.7%(95%CI:6.0%,7.4%)]than Provincial Colleges[5.0%(95%CI:4.5%,5.5%)and 3.2%(95%CI:2.8%,3.6%)]and Colleges Directly Under the Central Ministries and Commissions or Co-sponsored by Province and Ministry[3.2%(95%CI:2.9%,3.6%)and 1.9%(95%CI:1.7%,2.2%)].Stress relief(73.1%),curiosity(11.3%),and socializing(10.8%)were the leading reasons for smoking initiation.Conclusion:Concerted efforts are needed to reduce tobacco use among college students,including strengthening campus-level tobacco control policies,addressing smoking initiation during the transition to college,considering stronger age-related sales restrictions,and delivering tailored interventions targeting stress,peer influence,and curiosity-driven behaviors. 展开更多
关键词 smoking prevalence smoking initiation curiosity college students China higher vocational colleges gender differences stress relief
Impact toughness,crack initiation and propagation mechanism of Ti6422 alloy with multi-level lamellar microstructure 认领 引用
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作者 Jie Shen Zhihao Zhang Jianxin Xie 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2026年第2期595-609,共15页
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 αp lamellae,as well as nanoscale αs 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 αp lamella content,reduced the αs phase content,expanded theαcolonies and αp lamellae size,and improved the impact toughness from 22.7 to 53.8 J/cm2.Additionally,under the same solution treatment,raising the aging temperature from 500 to 700℃ resulted in a decrease in the αs phase content and a growth in the thickness of the αp lamella and αs phase.The impact toughness increased significantly with these changes.Samples with high αp lamellae content or large αs phase size exhibited high crack initiation and propagation energies.Impact deformation caused severe kinking of the αp 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 αp lamellae continuously deflect the crack propagation direction,inhibiting crack propagation. 展开更多
关键词 novel titanium alloy multi-level lamellar microstructure impact toughness crack initiation and propagation
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Rationale and design of the Early Initiation of Intensification Lipid-Lowering Treatment in Acute Coronary Syndrome(ELITEACS):a real-world study 认领 引用
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作者 Ya-Ni YU Ying WANG +3 位作者 Xiao-Dan TUO Zong-Xing LI Dan-Dan LI Yun-Dai CHEN 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2026年第4期246-256,共11页
OBJECTIVE To investigate the effects of early in-hospital intensive lipid-lowering therapy(LLT)with proprotein convertase subtilisin/kexin type 9(PCSK9)inhibitors on lipid dynamics and clinical outcomes in Chinese acu... OBJECTIVE To investigate the effects of early in-hospital intensive lipid-lowering therapy(LLT)with proprotein convertase subtilisin/kexin type 9(PCSK9)inhibitors on lipid dynamics and clinical outcomes in Chinese acute coronary syndrome(ACS)patients,providing robust real-world evidence for its long-term benefits and optimal implementation timing to address the evidence gap in optimal lipid management for secondary prevention.METHODS&RESULTS This multicenter prospective real-world study(http://gffzz1caf53c915c04334hf5kfcfv0upvw6v69.ffgz.tsg.suse.edu.cn,NCT number:NCT06738758),which building upon the ELEGANT pilot registry(ChiCTR2200065861),will enroll 6000 consecutively hospitalized ACS patients with uncontrolled dyslipidemia across more than 30 Chinese centers.Participants are enrolled based on recommended stratified proportions[(1)diagnostic categories:ST-segment elevation myocardial infarction:non-ST-segment elevation myocardial infarction:intermediate-high-risk unstable angina=1:1:3;and(2)lipid-lowering strategies:PCSK9 inhibitor±statin:statin+ezetimibe/hybutimibe:statin=2:1:2).Treatment assignment reflects real-world clinical decisions guided by low-density lipoprotein cholesterol levels and patient preference.Twelve-month follow-up assessments were conducted at predefined intervals:baseline hospitalization,discharge,and 1,3,6,12 months post-discharge.Primary endpoints were the goal attainment(low-density lipoprotein cholesterol<1.4 mmol/L)rates across treatment arms.Key secondary endpoints were the major adverse cardiovascular events(including myocardial infarction,ischemic stroke,cardiovascular mortality,coronary revascularization)and all-cause death,and other secondary endpoints encompassed time-to-lipid-goal,longitudinal changes in lipids profiles and inflammatory biomarkers,and perivascular fat attenuation index evolution quantified by coronary computed tomographic angiography.Propensity score matching and inverse probability treatment weighting will address confounding bias.CONCLUSIONS This study will pioneer evidence clarifying the optimal therapeutic window and clinical benefits of in-hospital intensive LLT for Chinese ACS patients.By establishing the first Chinese population-derived evidence for the“early intensive and rapid target attainment”strategy,our findings may challenge stepwise LLT paradigms.These results may guide international guideline updates for highrisk ACS populations,particularly in East Asian cohorts with distinct lipid profiles. 展开更多
关键词 Real world evidence clinical outcomes Early initiation Acute coronary syndrome Intensification lipid management Lipid lowering treatment PCSK inhibitors
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Convection Initiation of Short-term Heavy Rainfall Events in Shanghai Under the Influence of the Western Pacific Subtropical High During the 2022 Extreme Heatwave 认领 引用
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作者 CHEN Shi-qi YUE Cai-jun GAO Yue 《Journal of Tropical Meteorology》 SCIE CAS CSCD 2026年第3期271-287,共17页
Downdrafts tend to suppress convection under the influence of the western Pacific subtropical high(WPSH);however,local short-term heavy rainfall(STHR)events still occur frequently in coastal cities,and predicting the ... Downdrafts tend to suppress convection under the influence of the western Pacific subtropical high(WPSH);however,local short-term heavy rainfall(STHR)events still occur frequently in coastal cities,and predicting the convective initiation(CI)of such processes remains challenging.Based on ERA5 reanalysis data and an automatic weather station(AWS)network,the meteorological conditions of STHR and non-rainfall(NR)events were compared and analyzed using hourly synthesis analysis methods.The findings are as follows.(1)Suppression by the WPSH results in stronger vertical upward motion during STHR events,with-0.04≤ω≤-0.03 Pa s-1,than during NR events,with -0.03≤ω≤-0.015 Pa s-1.(2)STHR events,with over 80% AWSs≥38℃,exhibit quicker temperature rises,higher peak temperatures,and more extensive areas of heat coverage compared to NR events,with only 16.5%AWSs≥38℃.(3)STHR events,with a convergence of the Q vector divergence of-0.4×10-11hPa-1s-3,compared to NR events,with a convergence of the Q vector divergence of-0.2×10-11hPa-1s-3,are also accompanied by more intense surface convergence and upward motion,conditions which reveal the significance of local dynamics in triggering such weather events.(4)The weaker suppressive effect of the WPSH,combined with a significant mesoscale thermodynamic force near the ground,creates a multiscale resonance effect,which is a key condition for triggering local convection.(5)The lower temperature–dew point temperature spread(T-Td)at 2 m and relative humidity below 850 hPa for STHR events indicate that moisture conditions are sufficient,but not necessary,for triggering local convection.This study provides new insights into CI mechanisms under the influence of the WPSH for STHR events,thus offering important clues for future improvements in forecasting capabilities. 展开更多
关键词 short-term heavy rainfall western Pacific subtropical high vertical upward motion convection initiation
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Mineral-chemical and thermobarometric constraints on magma evolution during relict subduction initiation in the Laxmi Basin,Northern Indian Ocean 认领 引用
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作者 Anju Pandey Dhananjai K.Pandey 《Acta Geochimica》 EI CAS CSCD 2026年第3期703-717,共15页
Precise crustal characterisation of the Laxmi Basin(LB)in the northern Indian Ocean has intrigued researchers for several decades.The LB plays a vital role in the final dispersal of Gondwana and the early opening of t... Precise crustal characterisation of the Laxmi Basin(LB)in the northern Indian Ocean has intrigued researchers for several decades.The LB plays a vital role in the final dispersal of Gondwana and the early opening of the Arabian Sea.The International Ocean Discovery Program(IODP)Expedition 355 penetrated igneous basement in the LB for the first time and recovered forearc basalts(FAB)and boninitic forearc basalts(B-FAB)from Site U1457.Here,we investigate crystallisation and differentiation conditions of the source magma using mineral-chemical and thermobarometric constraints.Analyses of these basalts characterise the clinopyroxenes as high-Mg augites with low TiO2,high large-ion lithophile element(LILE)concentrations,negative Nb anomalies,and low total rare earth element(REE)contents.Most of the clinopyroxenes exhibit positive Eu anomalies in chondrite-normalised profiles,indicating their crystallisation prior to plagioclase.Plagioclases,on the other hand,range from labradorite to bytownite with flat to slightly light REE(LREE)-enriched patterns and positive Eu anomalies.Furthermore,clinopyroxene thermobarometry suggests crystallisation at~1.5-6 kbar pressure(i.e.,~9-22 km depth)within the estimated temperature range of 1053-1219℃.We infer that crystallisation may have peaked at approximately 3.25-4.25 kbar(~15-20 km),aligning with Moho depths(~12-14 km),followed by differentiation in sub-crustal and near-surface reservoirs(~10-11 km).Overall mineral-chemical signatures and pressure-temperature conditions confirm a nascent subduction origin of LB lavas. 展开更多
关键词 Laxmi Basin International Ocean Discovery Program(IODP) Expedition 355 Site U1457 Mineral chemistry Thermobarometry Subduction initiation
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Computational methods to predict RCF crack initiation hot spots in rails using critical plane SWT damage indicator parameter 认领 引用 被引量：1
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作者 Jonathan Leung Saeed Hossein‑Nia +1 位作者 Mårten Olsson Carlos Casanueva 《Railway Engineering Science》 EI 2026年第2期294-313,共20页
Predicting rolling contact fatigue crack hot spots or regions with increased local driving forces in rails is challenging due to the wide range of factors that influence crack initiation.Rail sections experience fluct... Predicting rolling contact fatigue crack hot spots or regions with increased local driving forces in rails is challenging due to the wide range of factors that influence crack initiation.Rail sections experience fluctuating creepage conditions,contact positions,and loads throughout their lifespan,influencing the development and location of fatigue cracks.A new computational method is proposed that predicts the orientation and regions prone to rolling contact fatigue cracks under realistic service loading.It combines multi-body simulations,finite element analysis,and critical plane approaches.A novel multi-variable sampling technique simplifies loading spectra into representative traction profiles,which are then analyzed using finite element analysis and the Smith-Watson-Topper damage indicator parameter(DIPSWT).The maximum DIPSWTvalue identifies the critical plane and potential crack orientation.A case study on the Swedish heavy haul train line(Malmbanan)considers measured traffic and loading conditions,analyzing the wheel load spectrum for a 384 m long section of a R=450 m curve.Results show that the DIPSWTis highest for the locomotive with a loaded payload configuration,with a maximum value of 3.84×10−8located at 38.59 mm from the lower gauge face corner.The DIPSWTcritical plane aligns with experi-mental measurements of RCF cracks orientations near the gauge corner.This computational method,when combined with other predictive tools,can efficiently identify conditions that lead to RCF cracks and determine their possible locations and orientations in railway tracks. 展开更多
关键词 Rolling contact fatigue Fatigue crack initiation Critical plane method Damage parameters Contact mechanics
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Spatiotemporal Variation and Environmental Conditions of Convective Initiations in Western Jiangnan,China 认领 引用
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作者 WU Zhen-zhen HAN Yu +4 位作者 SONG Nan OU Xiao-feng YE Cheng-zhi YANG Si-xiao XIANG Gang 《Journal of Tropical Meteorology》 SCIE CAS CSCD 2026年第3期288-301,共14页
Convective initiations(CIs)in western Jiangnan,China,were examined using radar data spanning April–September 2018–2021.Our approach combined objective identification and subjective validation to identify,track,and v... Convective initiations(CIs)in western Jiangnan,China,were examined using radar data spanning April–September 2018–2021.Our approach combined objective identification and subjective validation to identify,track,and validate the CIs,thereby producing a highly accurate CI dataset.Using this dataset,we investigated the spatiotemporal variations and environmental conditions associated with CIs and revealed distinct seasonal and diurnal patterns of CI events.Spatially,CIs occur more frequently south of the Nanling Mountains and less frequently in the north.Seasonally,they were most frequent from June to August,and least frequent in April and September,following a unimodal distribution.The CIs exhibited pronounced afternoon convection,particularly from June to August,when most occurred between 11:00 and 19:00 local time(UTC+8 h).Terrain significantly influenced the spatial variation in the CIs.North of the Nanling Mountains,CIs occurred near higher mountains,whereas south of the range,they were concentrated near smaller mountains and along the Guangdong coast.Using K-means clustering,CIs that could develop into Mesoscale Convective Systems were classified into four circulation types:Western Pacific subtropical high(WPSH)control(TypeⅠ),WPSH edge(TypeⅡ),southwest airflow(TypeⅢ),and low trough shear(TypeⅣ).The CIs of TypesⅠandⅡwere primarily attributed to afternoon thermal convection,which occurs under conditions of high moisture and thermal instability.Triggers for these CIs mostly occurred near high-elevation terrain.In contrast,TypesⅢandⅣwere driven primarily by the synergy of abundant moisture conditions and synoptic dynamic factors,such as low-level jets,upper-level troughs,and shear lines.These types exhibited higher frequency in the south,with high-frequency CI trigger zones particularly observed in regions with strong moisture-flux convergence and near complex terrain. 展开更多
关键词 radar convective initiation objective identification technique spatiotemporal variation environmental conditions
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Study on the initiation characteristics of oblique detonation waves induced by curved surfaces in acetylene-air mixtures 认领 引用
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作者 Yirong Xin Gaoxiang Xiang +1 位作者 Yichen Zhang Qiu Wang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第3期504-516,共13页
The reliable initiation of oblique detonation waves(ODWs)represents a critical factor determining the operational performance of oblique detonation engines(ODEs).While previous research has predominantly focused on id... The reliable initiation of oblique detonation waves(ODWs)represents a critical factor determining the operational performance of oblique detonation engines(ODEs).While previous research has predominantly focused on idealized semi-infinite wedge configurations,such studies have consistently revealed challenges including wave instability,detonation quenching,and compromised engine efficiency.This study presents a numerical investigation of initiation mechanisms and flow field characteristics in ODWs induced by curved surfaces.The analysis employs two-dimensional,multispecies,compressible Reynolds-averaged Navier-Stokes equations coupled with a detailed acetylene combustion model.Key results demonstrate that curved-surface-induced detonations achieve a substantially wider standing range than wedge-induced counterparts,primarily attributable to sustained compression effects generated by concave geometries.Notably,at small wedge angles,the curved surface configuration significantly reduces the detonation initiation distance.The initial formation phase reveals unstable behavior characterized by the large-angle overdriven detonation wave originating from the downstream steep wall section,which subsequently migrates upstream before stabilizing.Detailed examination of the wave structure identifies four distinct components:a curved shock wave(CSW),an overdriven detonation front,a transmitted shock wave,and a supersonic jet flow.Within this configuration,we observe an alternating reflection pattern of expansion waves and compression waves in the supersonic jet region,arising from Type IVr shock-shock interactions between the overdriven detonation wave and the CSW.Viscous effects analysis shows that the gradual curvature transition between the wall and flat plate effectively attenuates shock wave/boundary layer interactions.Furthermore,increased boundary layer thickness is found to significantly alter the ODW morphology while simultaneously inhibiting upstream propagation of the downstream overdriven detonation wave.These findings provide fundamental insights into the complex fluid dynamics governing ODEs,offering valuable implications for the development of more stable and efficient propulsion systems. 展开更多
关键词 Oblique detonation Curved surfaces Initiation characteristics Shock interaction Boundary layer
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Fracture initiation and propagation laws of supercritical CO2shock fracturing 认领 引用
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作者 YU Xing WANG Haizhu +7 位作者 SHI Mingliang WANG Bin DING Boxin ZHANG Guoxin FAN Xuhao ZHAO Chengming STANCHITS Sergey CHEREMISIN Alexey 《Petroleum Exploration and Development》 SCIE 2026年第1期272-284,共13页
To investigate the fracture initiation and propagation behavior of fractures in tight sandstone under the supercritical CO2(SCCO2)shock fracturing,laboratory fracturing experiments were conducted using a true-tr... To investigate the fracture initiation and propagation behavior of fractures in tight sandstone under the supercritical CO2(SCCO2)shock fracturing,laboratory fracturing experiments were conducted using a true-triaxial-like SCCO2shock fracturing system.Computed tomography(CT)scanning and three-dimensional fracture reconstruction were employed to elucidate the effects of shock pressure,pore pressure,and in-situ stress on fracture characteristics.In addition,nuclear magnetic resonance(NMR)transverse relaxation time spectra were used to assess the internal damage induced by SCCO2shock fracturing.The results indicate that,compared with conventional hydraulic fracturing and SCCO2quasi-static fracturing,SCCO2shock fracturing facilitates multidirectional fracture initiation and the formation of complex fracture networks.Increasing shock pressure more readily activates bedding-plane weaknesses,with main and subsidiary fractures interweaving into a dense fracture network.Under the same impulse intensity,elevated pore pressure reduces the effective normal stress and alters stress-wave scattering paths,thereby inducing more branch fractures and enhancing fracture complexity.An increase in differential in-situ stress promotes fracture propagation along the direction of the maximum principal stress,reduces branching,and simplifies fracture morphology.With increasing SCCO2shock pressure,pore volume and connectivity generally increase:small-to-medium pores primarily respond through increased number and enhanced connectivity;when the shock pressure rises to 40-45 MPa,crack coalescence generates larger pores and fissures,which play a dominant role in improving flow pathways and effective storage space,ultimately forming a multiscale pore-fracture network. 展开更多
关键词 supercritical CO2 shock fracturing waterless fracturing fracture initiation fracture propagation
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Initiation mechanism of diluted debris flows in hilly areas:A case study of the Laomaoshan region 认领 引用
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作者 WANG Yuzheng NIE Lei +2 位作者 XING Liting XU Junxiang ZHAO Degang 《Journal of Mountain Science》 SCIE CSCD 2026年第6期2490-2507,共18页
Dilute debris flows in hilly regions pose persistent threats to human life and property,as evidenced by catastrophic events in the Laomaoshan area of Dalian City,China,yet their underlying initiation mechanisms remain... Dilute debris flows in hilly regions pose persistent threats to human life and property,as evidenced by catastrophic events in the Laomaoshan area of Dalian City,China,yet their underlying initiation mechanisms remain insufficiently understood.This study systematically investigates the mechanisms through an integrated approach combining physical model experiments,PFC3D numerical simulations,and theoretical mechanical analysis.Results indicate that the initiation is a progressive,gradation-controlled process driven by mesoscopic structural degradation.We propose a novel four-stage hydro-mechanical framework to elucidate this process:(1)Rainfall Infiltration,characterized by rapid matric suction dissipation and the initial weakening of strong contact force chains;(2)Initial Slip,driven by porosity-induced dilation and enhanced localized hydraulic forces at the slope toe;(3)Fissure Development,where fluid-solid velocity disparities exert substantial hydrodynamic drag on the soil skeleton,inducing retrogressive sliding;(4)Overall Mobilization,culminating in the complete collapse of the internal force network and rapid channelized fluidization.Furthermore,mesostructured soil dictates vulnerability,with discontinuously graded soils exhibiting higher susceptibility to sudden,liquefaction-like failure upon saturation.By linking mesoscopic internal yielding with macroscopic hydrodynamic entrainment,this study establishes a physically grounded framework.This coupled weakening–erosion mechanism distinguishes dilute debris flows from traditional viscous debris flows,offering a robust theoretical basis for improved prediction and early warning in analogous geomorphic environments. 展开更多
关键词 Hilly area Diluted debris flow Initiation mechanism Physical model Numerical simulation
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Prediction of excavation damaged zone depth of chamber groups by damage initiation and spalling limit:Numerical simulation and machine learning algorithms 认领 引用
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作者 Ziheng Xiao Ming Tao +2 位作者 Qizheng Zhao Muhammad Burhan Memon Zhixian Hong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第4期2686-2701,共16页
As underground chamber group structures increase,predicting excavation damage zones(EDZ)depth is crucial for maintaining chamber stability.Traditional prediction methods exhibit limitations in terms of accuracy and ef... As underground chamber group structures increase,predicting excavation damage zones(EDZ)depth is crucial for maintaining chamber stability.Traditional prediction methods exhibit limitations in terms of accuracy and efficiency.To address this,a predictive method integrating numerical simulations using the damage initiation and spalling limit(DISL)approach with Bayesian-optimized XGBoost(BOXGBoost)was developed.Initially,a FLAC3D numerical model was established,and 500 data groups were generated by adjusting the model parameters.BO-XGBoost was applied to predict the depths of the highly damaged zone(HDZ),inner EDZ(EDZi),and outer EDZ(EDZo).Subsequently,the evaluation was conducted using the root mean square error(RMSE),mean absolute error(MAE),variance accounted for(VAF),and coefficientof determination(R2).The results were compared with those of the light gradient boosting machine(LightGBM),back propagation neural network(BPNN),random forest(RF),and support vector machine(SVM),and a feature importance analysis was conducted.Finally,the method was applied to predict the EDZo depth of chambers in the Fankou lead-zinc mine.The results showed that BO-XGBoost demonstrates high predictive accuracy,outperforming the other models,with RMSE,MAE,VAF,and R2values for the depths of HDZ,EDZi,and EDZo of 0.053,0.041,89.8%,0.905;0.045,0.036,94.8%,0.958;and 0.064,0.051,95.4%,0.962,respectively.The chamber size and spacing significantlyinfluencethe EDZi and EDZo depths,with the excavation sequence causing variations in HDZ depth.In engineering applications,the EDZo depth prediction error for the chambers is within 5%,offering valuable insights for predicting EDZ depth in chamber groups. 展开更多
关键词 Excavation damage zones Chamber groups Damage initiation and spalling limit(DISL) Numerical simulation XGBoost
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Crack initiation behavior of extruded Mg-Gd-Y-Zn-Zr alloy containing long-period stacking ordered lamellae under very high cycle fatigue at high temperature 认领 引用
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作者 Min Zhan Zhongmin Xiao +6 位作者 Xue Li Xiangyu Wang Yajun Dai Chang Liu Yao Chen Qingyuan Wang Chao He 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2026年第3期285-298,共14页
This study systematically investigates the very high cycle fatigue(VHCF) behavior of an extruded Mg-Gd-Y-Zn-Zr alloy at room temperature and 150℃,with particular emphasis on elucidating the mechanisms of crack initia... This study systematically investigates the very high cycle fatigue(VHCF) behavior of an extruded Mg-Gd-Y-Zn-Zr alloy at room temperature and 150℃,with particular emphasis on elucidating the mechanisms of crack initiation under high temperature conditions.The results show that the alloy exhibits superior fatigue performance at 150℃ compared to room temperature.At ambient conditions,cracks predominantly initiate along basal slip systems,whereas elevated temperatures activate prismatic slip and twinning,resulting in more diverse crack initiation mechanisms.Furthermore,elevated temperature facilitates a more uniform distribution of plastic deformation,thereby enhancing fatigue resistance.Notably,a dense ZnO layer forms on the alloy surface at 150℃.Compared to the brittle and crack-prone MgO layer,this ZnO layer offers more effective surface protection and significantly delays crack initiation.The enhanced fatigue resistance is thus primarily attributed to the combined effects of the protective ZnO layer and the uniform plastic deformation.These findings provide theoretical guidance for optimizing the high-temperature fatigue performance of rare-earth magnesium alloys. 展开更多
关键词 Mg-Gd-Y-Zn-Zr alloy Very high cycle fatigue High temperature Crack initiation mechanism ZnO protective layer
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Phase-field modeling of shock initiation in β-HMX:From hotspot growth to steady detonation 认领 引用
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作者 Chengbo Wu Sui Jia +2 位作者 Yiyuan Jiang Songlin Yao Xiaoyang Pei 《Matter and Radiation at Extremes》 SCIE EI CAS CSCD 2026年第4期101-121,共21页
Understanding how hotspots affect detonation in energetic materials has important scientific and engineering value.The unique material propertie s of energetic materials impose limitations on research methods,particul... Understanding how hotspots affect detonation in energetic materials has important scientific and engineering value.The unique material propertie s of energetic materials impose limitations on research methods,particularly concerning the dynamic characteristics of mesoscale microstructures.In the present work,a coupled crystal plasticity and phase-field model is proposed to address shock initiation in β-HMX explosives.This model e mploys the phase-field approach to describe hotspot growth processes,enabling entire proce ss simulation from individual hotspot evolution to steady detonation.It quantitatively links collective evolution of multiple hotspots with experimentally measured macroscopic initiation characteristics across stages from slow reaction,through rapid growth,to steady detonation.Phase-field simulations provide a clear physical picture of shock-to-detonation transition(SDT):the growth of individual hotspot leads to the generation of a compression wave that interacts with and catches up to the shock front;numerous compression waves converge at the shock front to form steady detonation waves.Given the strong dependence of explosive SDT on hotspot density and distribution,this method quantifies how individual hotspot growth affects initiation properties.Consequently,it enables evaluation of internal hotspot density and distribution by inversely analyzing macroscopic shock-initiated particle velocity profiles.Furthermore,crystal plasticity simulations allow assessment of how shear strain energy and single-crystal anisotropy influence detonation performance.This work provides a novel means for simulating SDT in energetic explosives,demonstrating substantial engineering application prospects. 展开更多
关键词 hotspot growth steady detonation understanding how hotspots affect detonation energetic materials HMX mesoscale microstructuresin phase field modeling shock initiation
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Numerical Simulation of Interface Crack Initiation and Propagation Along Interphase in Multiphase Composites Using Arbitrary Multiphase Hybrid Stress Element 认领 引用
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作者 Wenyan Zhang Ran Guo +1 位作者 Wei Xu Runjie Wang 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2026年第5期711-721,共11页
Arbitrary multiphase hybrid stress finite element(AMHSFE)is a high-order stress element based on hybrid stress finite element theory,featuring extremely simple mesh division.It demonstrates strong capabilities for mul... Arbitrary multiphase hybrid stress finite element(AMHSFE)is a high-order stress element based on hybrid stress finite element theory,featuring extremely simple mesh division.It demonstrates strong capabilities for multiphase materials,particularly particulate reinforced composites(PRCs)with high amounts of particulate matter[1].Since the behavior of interfaces in multiphase materials significantly impacts their mechanical properties,research on interface cracks in multiphase materials holds considerable significance.The AMHSFE is employed in this study to simulate interface cracks of varying morphologies in multiphase materials,as well as the whole process of the interface crack initiation and propagation in PRCs with varying particle quantities and distribution patterns.A comparison of the results with those from finite element method(FEM)software analyses demonstrates the analytical reliability,accuracy and validity of AMHSFE.Furthermore,the simulations demonstrate the capability of AMHSFE in analyzing interface crack initiation and propagation in realistic PRCs with tremendous amounts of particles. 展开更多
关键词 Arbitrary multiphase hybrid stress finite element(AMHSFE) Multiphase materials Particulate reinforced composites(PRCs) Interface crack initiation and propagation Numerical simulation
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Anatomy of the pre-pyloric vein and right gastroepiploic branches:Guiding the transection initiation site for sleeve gastrectomy 认领 引用
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作者 Sheng-Nan Zhou Hai-Tao Hu +7 位作者 Qing-Lin Li Zong-Ze Li Hua Yang Chao-Feng Li Xin Song Tao Tang LeiZhou Fan-Qiang Meng 《World Journal of Gastrointestinal Surgery》 SCIE 2026年第6期263-271,共9页
BACKGROUND Laparoscopic sleeve gastrectomy(SG)as an effective treatment for obesity and related metabolic diseases which still lacks consensus on gastric transection starting points.AIM To investigate reliable anatomi... BACKGROUND Laparoscopic sleeve gastrectomy(SG)as an effective treatment for obesity and related metabolic diseases which still lacks consensus on gastric transection starting points.AIM To investigate reliable anatomical landmarks to enhance surgical precision and improve outcomes.METHODS This observational study enrolled 100 patients with obesity who underwent laparoscopic SG between May and October 2024.Intraoperatively,the distance between the prepyloric vein and the first branch of the right gastroepiploic vessels crossing the midline of the pyloric canal(AB distance)was precisely measured to standardize transection initiation site for SG(TIS-SG),with the latter branch defined as the optimal TIS-SG.The study analyzed clinical parameters potentially affecting the AB distance,including sex,and body mass index(BMI).Furthermore,preoperative and postoperative changes in blood glucose and blood pressure were compared to assess the metabolic improvements associated with SG.RESULTS The average AB distance was 4.65±0.89 cm,with 4 patients exceeding the recommended maximum of 6 cm.No significant differences were found based on BMI,blood pressure,or fasting glucose levels(P>0.05).Male patients had a significantly larger AB distance compared to females(4.98±0.99 cm vs 4.53±0.84 cm,P=0.027).Additionally,fasting blood glucose levels on the third postoperative day showed a significant reduction compared to preoperative levels(P<0.001).CONCLUSION The AB distance is a stable and reliable anatomical marker for defining TIS-SG in SG,independent of metabolic factors and BMI.SG leads to short-term metabolic improvements,including better blood glucose and blood pressure control. 展开更多
关键词 Metabolic improvement Surgical precision Obesity Right gastroepiploic artery Pre-pyloric vein Transection initiation site Laparoscopic sleeve gastrectomy
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Empowering early breastfeeding:Determinants of timely initiation among the infants in a rural Indian medical centre 认领 引用
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作者 Dipika M Mashalkar Mahesh N Sonar +3 位作者 Dattatray V Kulkarni Vidyadevi D Kendre Basawraj S Warad Basavraj S Nagoba 《World Journal of Clinical Pediatrics》 2026年第3期245-253,共9页
BACKGROUND Initiating breastfeeding within the first hour after birth is a proven intervention for improving newborn survival and long-term health outcomes.Despite its recognized advantages,early initiation of breastf... BACKGROUND Initiating breastfeeding within the first hour after birth is a proven intervention for improving newborn survival and long-term health outcomes.Despite its recognized advantages,early initiation of breastfeeding(EIBF)remains limited in India,and data from rural Maharashtra are scarce.AIM To determine the prevalence of EIBF and explore maternal and delivery-related factors influencing its practice among late preterm and term infants in a rural tertiary care hospital.METHODS This observational study was conducted over a period of 18 months,from May 2022 to October 2023 and included 380 neonates born at≥34 weeks of gestation.Information on maternal sociodemographic profile,delivery characteristics,antenatal counselling,breastfeeding practices,and early maternal or neonatal health concerns was collected through a structured interview of the mothers and the accompanying attendants and hospital records at birth and within 6 hours of birth.Data were analysed using descriptive statistics.Appropriate association tests were applied.RESULTS EIBF was reported in 50.8%of newborns,higher than the National Family Health Survey-5 national estimate of 41.8%,but still below the desired levels.Mothers who received antenatal maternal counselling[P<0.05,adjusted odds ratio(aOR)=3.5],had prior breastfeeding experience(P<0.05,aOR=2.4),and had vaginal deliveries(P<0.05,aOR=2.4)were more likely to initiate breastfeeding within the first hour.Caesarean births(P<0.05,aOR=0.4),maternal illness(P<0.05,aOR=0.3),and lactation problems(P<0.05,aOR=0.2)were associated with delays.No significant relationships were observed between maternal age,residence,education,occupation,religion,parity,or birth spacing and the practice of giving prelacteal feeds.Among the modifiable influences,antenatal advice emerged as the strongest predictor of success.CONCLUSION Interventions focusing on antenatal counselling during pregnancy and providing enhanced lactation support for surgical deliveries,and addressing the lactational problems by appointing a dedicated nurse,may substantially improve EIBF.Strengthening these measures can improve neonatal outcomes and align with national and global child health targets. 展开更多
关键词 Early initiation of breastfeeding Lactation problems Antenatal counselling Colostrum Prelacteal feeding First hour
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