In this article,by employing the Hirota bilinear approach and the long wave limit method,we not only derive soliton solutions,lump solutions,and hybrid solutions for the(2+1)-dimensional Yu-Toda-Sasa-Fukuyama(YTSF)equ...In this article,by employing the Hirota bilinear approach and the long wave limit method,we not only derive soliton solutions,lump solutions,and hybrid solutions for the(2+1)-dimensional Yu-Toda-Sasa-Fukuyama(YTSF)equation,but also analyze the dynamical behaviors of nonlinear local wave propagation in shallow water.Firstly,based on the Hirota bilinear approach,one to four-order soliton solutions of the YTSF equation are obtained,and the effects of different parameters on the amplitude,propagation trajectory,and displacement of solitons are investigated.Secondly,using the long wave limit approach,one to three-order lump solutions and various physical quantities of the YTSF equation are derived.It is found that the real and imaginary parts of the parameter pi dominate the propagation trajectory and the shape of lump waves,respectively.Furthermore,we construct the hybrid solution for the YTSF equation,leading to the conclusion that the interaction between lumps and solitons constitutes an elastic collision.To intuitively understand the dynamic behaviors of these solutions,we conduct numerical simulations to present vivid three-dimensional visualizations.展开更多
Background:Adolescent suicide remains a pressing public health concern in South Korea and worldwide,ranking as one of the leading causes of death among youth.Identifying modifiable risk and protective factors is criti...Background:Adolescent suicide remains a pressing public health concern in South Korea and worldwide,ranking as one of the leading causes of death among youth.Identifying modifiable risk and protective factors is critical for prevention strategies.Physical activity has been suggested as one such factor due to its potential mental health benefits.This study aimed to examine whether associations between physical activity and suicidality differ by activity type and by stage of suicidal behavior,distinguishing suicidal ideation,planning,and attempts among Korean adolescents.Methods:This cross-sectional secondary analysis used data from the 20th Korea Youth Risk Behavior Web-based Survey(KYRBS)conducted in 2024,a nationally representative survey of Korean adolescents.The study included 54,653 middle and high school students with complete data on physical activity,suicidal ideation,planning,and attempts.Three types of physical activity(vigorous activity,muscle-strengthening activity,and≥60 min of daily physical activity)were examined.Associations with suicidal behaviors were analyzed using multivariable logistic regression models,adjusting for psychological,behavioral,and sociodemographic covariates.Results:In this nationally representative sample of Korean adolescents,engaging in at least 60 min of daily physical activity was significantly associated with lower odds of suicide planning,but not ideation or attempts.In contrast,muscle-strengthening activity was linked to increased odds of both suicide planning and attempts,whereas vigorous activity showed no significant associations.Psychological factors,including generalized anxiety,sadness,stress,and loneliness,showed strong associations with suicidal behaviors and were included as covariates in the adjusted models.Female students,low academic performance,and unstable residential status were also associated with higher odds of suicidal behaviors.Conclusion:The associations between physical activity and suicidality differed by activity type and suicidal outcome;muscle-strengthening activity was positively associated with suicide planning and attempts in adjusted models.展开更多
Objective: To analyze the impact of motivational nursing under the solution-focused approach on health behaviors in surgical care for bladder cancer patients. Methods: A sample of 72 bladder cancer patients who underw...Objective: To analyze the impact of motivational nursing under the solution-focused approach on health behaviors in surgical care for bladder cancer patients. Methods: A sample of 72 bladder cancer patients who underwent surgical treatment from September 2024 to September 2025 was randomly divided into groups using a random number table. Group A received motivational nursing under the solution-focused approach, while Group B received conventional nursing. Health behavior scores and complication indicators were compared between the two groups. Results: Group A had higher scores on the Health-Promoting Lifestyle Profile II (HPLP-Ⅱ) than Group B, with p < 0.05. The postoperative complication rate in Group A was lower than that in Group B, with p < 0.05. Conclusion: For bladder cancer patients undergoing surgery, receiving motivational nursing under the solution-focused approach can improve health behaviors, alleviate negative emotions, and is highly feasible and effective.展开更多
The volume change behavior of natural gas hydrate-bearing sediment is essential as it influences settlement,strength,and stiffness,which directly affect the stability of hydrate reservoirs during hydrate extraction or...The volume change behavior of natural gas hydrate-bearing sediment is essential as it influences settlement,strength,and stiffness,which directly affect the stability of hydrate reservoirs during hydrate extraction or in response to environmental changes.The volume change is influenced not only by stress but also by the formation and dissociation of hydrates.This study adopted a customized apparatus for one-dimensional compression tests,allowing independent control of gas pressure and effective stress.Tests were conducted on samples with different hydrate saturations along various temperature-gas pressure-effective stress paths,yielding some conclusions related to compressibility and creep.An unusual phenomenon was observed under low-stress conditions:hydrate formation led to shrinkage rather than expansion.Three potential mechanisms behind this occurrence were discussed.As hydrate saturation increases,the yield stress rises while the compression and swelling indexes remain minimally affected.After hydrate dissociation,the compression curve of hydrate-bearing sediment drops to that of hydrate-free sediment.Once hydrate is formed,the compression curve of hydrate-free sediment gradually approaches that of hydrate-bearing sediment during the subsequent loading.Under low-stress conditions,the creep of both hydrate-free and hydrate-bearing sediments is very weak.However,when stress increases,significantly beyond the yield stress,the creep of both sediments increases significantly,with hydrate-bearing sediment exhibiting much greater creep than hydrate-free sediment.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
Objectives:24-h movement behaviors(24-HMB),encompassing physical activity,sedentary behavior,and sleep duration,are increasingly regarded as interrelated and important factors for mental health.However,evidence on the...Objectives:24-h movement behaviors(24-HMB),encompassing physical activity,sedentary behavior,and sleep duration,are increasingly regarded as interrelated and important factors for mental health.However,evidence on the comprehensive association of these behaviors with mental health in adults with diabetes in developing countries remains scarce.This study examined the association between 24-HMB guidelines and psychological health among adults with diabetes in developing countries.Methods:Data were retrieved from the World Health Organization’s study on Global Aging and Adult Health Survey dataset.Adults(N=1905)diagnosed with diabetes from five low-and middle-income countries were included.The exposure of interest was adherence to 24-HMB guidelines,depression,cognition,and quality of life(QoL).Multiple logistic and multiple linear regression analyses were used to examine the association between meeting 24-HMB guidelines and depression,cognition,and QoL,respectively.Results:This cross-sectional study revealed that 28.61%complied with all three 24-HMB guidelines.Diabetic patients who met more numbers of 24-HMB guidelines had lower depression risk(OR=0.74,95%CI:0.61 to 0.91,p=0.004),greater cognition(β=0.42,95%CI:0.25 to 0.60,p<0.001),and QoL(β=1.30,95%CI:1.04 to 1.55,p<0.001)with the non-compliant population.For specific combinations,meeting all three guidelines were significantly associated with lower odds of depression,improved cognitive function,and enhanced QoL(all p<0.001).Conclusion:These findings support that meeting 24-HMB guidelines in a single or combined movement behaviors was significantly related to reduced risk of depression,enhanced cognitive function,and improved QoL among individuals with diabetes.展开更多
To investigate the aging mechanisms and elucidate the correlations between unstable microstructure and performance in biodegradable Zn alloys,the accelerated aging experiment was conducted on a high-performance wrough...To investigate the aging mechanisms and elucidate the correlations between unstable microstructure and performance in biodegradable Zn alloys,the accelerated aging experiment was conducted on a high-performance wrought Zn−0.1Mg alloy by annealing at 200℃ for varying durations.The findings reveal that the tensile strength of the alloy rapidly and significantly declines with prolonged annealing time,decreasing from 383 MPa for the as-received alloy to 102 MPa for the alloy subjected to 1440 min of annealing.The primary factors contributing to this considerable reduction in strength are static recrystallization,grain coarsening,and dislocation annihilation.Initially,the ductility of the alloy shows fluctuations,ultimately experiencing a marked decrease after extended annealing.This decline is linked to the grain growth and heightened texture intensity,while the unusual increase in ductility observed between 30 and 120 min of annealing is likely due to the formation of twins.In addition,due to rapid grain growth and an increase in precipitates and twins,the corrosion resistance of the alloy in Hank’s solution has worsened,with the corrosion rate rising from 0.037 to 0.069 mm/a following 300 min of annealing.展开更多
Objective This study aimed to describe 24-hour movement behaviors,including physical activity,sedentary behavior,and sleep period,among Chinese preschoolers using nationally representative data,and examine disparities...Objective This study aimed to describe 24-hour movement behaviors,including physical activity,sedentary behavior,and sleep period,among Chinese preschoolers using nationally representative data,and examine disparities by age,gender,and residence.Methods A cross-sectional analysis was conducted using data from the China National Nutrition and Health Systematic Survey for Children(2019–2021),including 10,935 children aged 3–5 years.Daily total time of physical activity(TPA),total time of sedentary behaviors(TSB),and total sleep period(TSP)was collected via validated structured questionnaires.Physical inactivity was defined as<180 minutes of TPA per day.Results Median TPA was 121.4(IQR:71.4−209.6)minutes/day,and TSB was 231.4(IQR:175.0−304.3)minutes/day,with 11.46±1.00 hours/day average TSP.Overall,68.8%were physically inactive,with higher prevalence in rural(73.3%)versus urban areas(64.8%,P<0.001).TPA and TSB increased with age,while TSP decreased(all P<0.001).No significant gender differences were observed.Conclusion Most Chinese preschoolers exhibit insufficient physical activity and excessive sedentary behaviors,with notable urban–rural disparities and an escalating trend of ageing.Continuous monitoring and targeted interventions,especially in rural areas,are urgently needed.展开更多
Healthy behavior has long been linked to mental health outcomes.However,the role of artificial intelligence(AI)literacy in shaping healthy behaviors and its potential impact on mental health remains underexplored.This...Healthy behavior has long been linked to mental health outcomes.However,the role of artificial intelligence(AI)literacy in shaping healthy behaviors and its potential impact on mental health remains underexplored.This paper presents a scoping review offering a novel perspective on the intersection of healthy behaviors,mental health,and AI literacy.By examining how individuals’understanding of AI influences their choices regarding nutrition and their susceptibility to mental health issues,the current study explores emerging trends in health behavior decision-making.This emphasizes the need for integrating AI literacy into mental health and health behaviors education,as well as the development of AI-driven tools to support healthier behavior choices.It highlights that individuals with low AI literacy may misinterpret or overly depend on AI guidance,resulting in maladaptive health choices,while those with high AI literacy may be more likely to engage reflectively and sustain positive behaviors.The paper outlines the importance of inclusive education,user-centered design,and community-based support systems to enhance AI literacy for digitally marginalized groups.AI literacy may be positioned as a key determinant of health equity,better allowing for interdisciplinary strategies that empower individuals to make informed,autonomous decisions that promote both physical and mental health.展开更多
A fine-grained metastable dual-phase Fe_(40)Mn_(20)Co_(20)Cr_(15)Si_(5)high entropy alloy(CS-HEA)with excellent strength and ductility was successfully prepared by friction stir processing(FSP).The microstructural and...A fine-grained metastable dual-phase Fe_(40)Mn_(20)Co_(20)Cr_(15)Si_(5)high entropy alloy(CS-HEA)with excellent strength and ductility was successfully prepared by friction stir processing(FSP).The microstructural and mechanical properties of the fine-grained CS-HEA were characterized.The results showed that as-cast shrinkage cavities and elemental segregation were eliminated.The average grain size was refined from 121.1 to 5.4μm.The face-centered cubic phase fraction increased from 23%to 82%.During tensile deformation,dislocation slip dominated at strains ranging from 5%to 17%,followed by transformation induced plasticity(TRIP)from 17%to 26%,and twin induced plasticity(TWIP)from 26%to 37%.The yield strength,ultimate tensile strength,and elongation of the fine-grained CS-HEA were 503 MPa,1120 MPa,and 37%,respectively.The strength-ductility synergy of fine-grained CS-HEA was attributed to the combined effects of TRIP,TWIP,dislocation strengthening,and fine-grained strengthening.展开更多
Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.C...Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.Current research on the associations between 24-hour movement behaviors(including physical activity,sedentary behavior,and sleep)and depression has largely been confined to examining the effects of single behaviors,overlooking the intrinsic compositional nature and interrelationships among these behaviors.Therefore,it is necessary to investigate the integrated effects of 24-hour movement behaviors on depression in older adults with multimorbidity from a holistic,compositional perspective.Methods:From November 2024 to April 2025,a total of 226 older adult patients with multimorbidity were recruited from a tertiary hospital in Changzhou City.Data were collected using a general information questionnaire,the International Physical Activity Questionnaire–Short Form(IPAQ-SF),the Pittsburgh Sleep Quality Index(PSQI),and the Patient Health Questionnaire-9(PHQ-9).Compositional data analysis and isotemporal substitution models were employed for statistical analysis.Results:The mean daily durations of Light-Intensity Physical Activity(LPA),Moderate-to-Vigorous Physical Activity(MVPA),Sedentary Behavior(SB),and Sleep(SLP)in older adults with multimorbidity were 402.48 min,12.04 min,511.52 min,and 458.68 min,respectively.The prevalence of depressive symptoms was 37.6%.Compositional data analysis revealed that SB was positively associated with depression(βSB=1.005,P=0.006),while SLP was negatively associated with depression(βSLP=−1.736,P<0.001).No statistically significant associations were found between MVPA or LPA and depression(P>0.05).In the 10-minute isotemporal substitution model,replacing SB with any other behavioral component was associated with a decrease in depression scores.Conversely,substituting SLP with either LPA or SB resulted in an increase in depression scores,while substituting SLP with MVPA led to a decrease in depression scores.The dose-response analysis revealed that,among the isotemporal substitution effects,replacing SB with SLP and replacing SLP with MVPA were the substitution pathways associated with the most rapid decline in depression scores,representing the greatest beneficial health effects.Conclusion:The prevalence of depression is notably high among older adults with multimorbidity.Reducing daily sedentary behavior(SB),maintaining adequate sleep(SLP),and increasing moderate-to-vigorous physical activity(MVPA)can improve depressive symptoms and enhance overall health in this population.展开更多
Accurately recognizing driver distraction is critical for preventing traffic accidents,yet current detection models face two persistent challenges.First,distractions are often fine-grained,involving subtle cues such a...Accurately recognizing driver distraction is critical for preventing traffic accidents,yet current detection models face two persistent challenges.First,distractions are often fine-grained,involving subtle cues such as brief eye closures or partial yawns,which are easily missed by conventional detectors.Second,in real-world scenarios,drivers frequently exhibit overlapping behaviors,such as simultaneously holding a cup,closing their eyes,and yawning,leading tomultiple detection boxes and degradedmodel performance.Existing approaches fail to robustly address these complexities,resulting in limited reliability in safety critical applications.To overcome these pain points,we propose YOLO-Drive,a novel framework that enhances YOLO-based driver monitoring with EfficientViM and Polarized Spectral–Spatial Attention(PSSA)modules.Efficient ViMprovides lightweight yet powerful global–local feature extraction,enabling accurate recognition of subtle driver states.PSSA further amplifies discriminative features across spatial and spectral domains,ensuring robust separation of concurrent distraction cues.By explicitly modeling fine-grained and overlapping behaviors,our approach delivers significant improvements in both precision and robustness.Extensive experiments on benchmark driver distraction datasets demonstrate that YOLO-Drive consistently out-performs stateof-the-art models,achieving higher detection accuracy while maintaining real-time efficiency.These results validate YOLO-Drive as a practical and reliable solution for advanced driver monitoring systems,addressing long-standing challenges of subtle cue recognition and multi-cue distraction detection.展开更多
Preliminary studies on emerging herbal ingredients have highlighted alternative pathways that inflammation and modulate perturbed immunity as valuable strategies for treating depression.Previous studies have shown tha...Preliminary studies on emerging herbal ingredients have highlighted alternative pathways that inflammation and modulate perturbed immunity as valuable strategies for treating depression.Previous studies have shown that 5-O-methylvisammioside,a bioactive compound derived from Saposhnikoviae Radix,possesses excellent anti-inflammatory and antioxidant biological functions,exhibits a neuroprotective effect.The purpose of this study was to explore the targets and signaling pathways of 5-O-methylvisammioside in the potential treatment of major depressive disorder using a combination of network pharmacology analysis and biological experiments.The network pharmacological analysis results indicated that the proto-oncogene tyrosine-protein kinase Src and the nuclear factor kappa B signaling pathway were highly correlated with the treatment of major depressive disorder with 5-O-methylvisammioside.Further experiments indicated that 5-O-methylvisammioside significantly improved lipopolysaccharide-induced depression-like behaviors in mice,ameliorated microglial polarization in the hippocampal CA1 and CA3 regions,and inhibited Src phosphorylation and nuclear factor kappa B pathway activation.The effects of 5-O-methylvisammioside were similar to those of the Src inhibitor PP2.When 5-O-methylvisammioside was administered with PP2,no effects were observed on lipopolysaccharide-induced depression-like behaviors in mice,nuclear factor kappa B pathway proteins,and microglial polarization.These findings indicate that 5-O-methylvisammioside may exert its antidepressant potential by inhibiting Src-mediated activation of the nuclear factor kappa B signaling pathway.Therefore,5-O-methylvisammioside might serve as a promising Chinese herbal medicine for the prevention and treatment of depression.展开更多
Long-term exposure to ambient fine particulate matter(PM2.5)may increase the risk of neurotoxicity in human populations.However,research studies on the underlying mechanisms of chronic PM2.5-induced depression-like be...Long-term exposure to ambient fine particulate matter(PM2.5)may increase the risk of neurotoxicity in human populations.However,research studies on the underlying mechanisms of chronic PM2.5-induced depression-like behaviors,and potential therapeutical strategies,remain scarce.In the present study,after long-term exposure to real-world PM2.5 for 15 weeks,male mice displayed depression-like behaviors,which were revealed using the open field and sucrose preference tests.Mechanistically,chronic PM2.5 exposure promoted astrocytic A1 polarization and disrupted reduction-oxidation balance in the mouse hippocampus.Furthermore,PM2.5-exposed mice displayed pathological damage to hippocampal neurons as well as the inhibition of nuclear factor erythroid 2-related factor 2 signaling.Astrocytic ablation of nuclear factor erythroid 2-related factor 2 exacerbated PM2.5-induced hippocampal neuronal injury in mice via the disruption of astrocyte-to-microglia communication;this finding was confirmed in mice with bilateral and unilateral hippocampal astrocytic Nfe2l2 knockdown.Importantly,the upregulation of nuclear factor erythroid 2-related factor 2 activation by procyanidin significantly ameliorated PM2.5-induced depression-like behaviors through the remodeling of astrocyte-to-microglia communication.Together,our findings shed light on the important role of hippocampal astrocytic nuclear factor erythroid 2-related factor 2 activation for maintaining astrocyte-to-microglia communication,and indicate potential research avenues for therapeutic strategies against PM2.5-induced depresson-like behaviors.展开更多
Four powder metallurgy(PM)Ni-based superalloys with different Hf and Ta contents were creep-tested at 650℃ and 970 MPa,700℃ and 770 MPa,and 750℃ and 580 MPa,respectively.The effect of Hf and Ta on creep deformation...Four powder metallurgy(PM)Ni-based superalloys with different Hf and Ta contents were creep-tested at 650℃ and 970 MPa,700℃ and 770 MPa,and 750℃ and 580 MPa,respectively.The effect of Hf and Ta on creep deformation behaviors of the superalloys was studied from multiple scales by SEM,electron backscatter diffraction(EBSD),and aberration-corrected scanning transmission electron microscope(AC-STEM).The results showed that Hf and Ta suppressed the intergranular fracture and initiation of cracks during the acceleration creep stage,which prolonged the creep rupture time.Hf and Ta inhibited the stacking faults extending and the dislocation climbing and promoted the Suzuki segregation of W during the steady-state creep stage,which reduced the minimum creep rate and delayed the start time of the acceleration creep stage.The Suzuki segregation of Co,Cr,Mo,Ti,Nb,W,and Ta along stacking faults was observed after Hf and Ta addition,leading to the localized phase transformation in the γ′phase,and the stacking fault phase was chemically disordered.This study provided ideas for the composition design of novel PM Ni-based superalloys and theoretical foundations for the combined addition of Hf and Ta.展开更多
Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological b...Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.展开更多
The influence of in-situ precipitation on corrosion behaviors of wire arc directed energy deposited (WADED) Al-Mg-(Sc-Zr) was studied. WADED Al-Mg showed a homogeneous microstructure with coarse equiaxed grains. WADED...The influence of in-situ precipitation on corrosion behaviors of wire arc directed energy deposited (WADED) Al-Mg-(Sc-Zr) was studied. WADED Al-Mg showed a homogeneous microstructure with coarse equiaxed grains. WADED Al-Mg-Sc-Zr exhibited fine equiaxed grains along the molten pool boundary (MPB) and inter-layer zone (ITZ) while coarse equiaxed grains were inside the molten pool. The in-situ precipitation resulted in the primary Al_(3)(Sc, Zr) aggregated along MPB and ITZ while minor-sized secondary Al_(3)(Sc, Zr) existed inside the molten pool. WADED Al-Mg-Sc-Zr showed improved electrochemical behavior than Al-Mg. WADED Al-Mg presented random pittings that occurred near dispersed β-Al_(3)Mg_(2). WADED Al-Mg-Sc-Zr exhibited pittings along MPB and ITZ, where Al_(3)(Sc, Zr) aggregated and induced galvanic corrosion. Corrosion anisotropy was obvious in Al-Mg-Sc-Zr since more MPBs and ITZs make the XOZ plane susceptive to localized corrosion.展开更多
This study aims to explore the characteristics of novice teachers’inappropriate behaviors in classroom teaching and their intervention strategies.With the continuous improvement of education quality,novice teachers f...This study aims to explore the characteristics of novice teachers’inappropriate behaviors in classroom teaching and their intervention strategies.With the continuous improvement of education quality,novice teachers face increasing challenges in teaching practice.Their inappropriate behaviors not only affect the classroom atmosphere but may also negatively impact students’learning outcomes.Therefore,researching the characteristics of novice teachers’inappropriate behaviors and their intervention strategies holds significant scientific and social value.This study employs a combination of quantitative and qualitative methods to analyze the behavioral patterns of novice teachers in classroom teaching and proposes corresponding intervention strategies.The results indicate that novice teachers’inappropriate behaviors mainly manifest as poor classroom management,monotonous teaching methods,and insufficient interaction with students.Based on these findings,the study proposes a series of effective intervention strategies,including enhancing teacher training,optimizing teaching design,and promoting positive interactions between teachers and students.The conclusions of the study not only provide practical guidance for educational practice but also point out directions for future research,emphasizing the crucial role of teacher professional development in improving teaching quality.展开更多
In order to understand the influence of ordering behaviors on the thermodynamic and mechanical properties of multi-principal element alloys(MPEAs),the temperature-dependent thermodynamic properties and mechanical prop...In order to understand the influence of ordering behaviors on the thermodynamic and mechanical properties of multi-principal element alloys(MPEAs),the temperature-dependent thermodynamic properties and mechanical properties of FCC_CoNiV MPEAs were comparatively predicted,where the alloys were modeled as the ordered configurations based on our previously predicted site occupying fractions(SOFs),as well as disordered configuration based on traditional special quasi-random structure(SQS).The ordering behavior not only improves the thermodynamic stability of the structure,but also increases the elastic properties and Vickers hardness.For example,at 973 K,the predicted bulk modulus(B),shear modulus(G),Young’s modulus(E),and Vickers hardness(HV)of FCC_CoNiV MPEA based on SOFs configuration are 187.82,79.03,207.93,and 7.58 GPa,respectively,while the corresponded data are 172.58,57.45,155.14,and 4.64 GPa for the SQS configuration,respectively.The Vickers hardness predicted based on SOFs agrees considerably well with the available experimental data,while it is underestimated obviously based on SQS.展开更多
Exploring dynamic mechanical responses and failure behaviors of hot dry rock(HDR)is significant for geothermal exploitation and stability assessment.In this study,via the split Hopkinson pressure bar(SHPB)system,a ser...Exploring dynamic mechanical responses and failure behaviors of hot dry rock(HDR)is significant for geothermal exploitation and stability assessment.In this study,via the split Hopkinson pressure bar(SHPB)system,a series of dynamic compression tests were conducted on granite treated by cyclic thermal shocks at different temperatures.We analyzed the effects of cyclic thermal shock on the thermal-related physical and dynamic mechanical behaviors of granite.Specifically,the P-wave velocity,dynamic strength,and elastic modulus of the tested granite decrease with increasing temperature and cycle number,while porosity and peak strain increase.The degradation law of dynamic mechanical properties could be described by a cubic polynomial.Cyclic thermal shock promotes shear cracks propagation,causing dynamic failure mode of granite to transition from splitting to tensile-shear composite failure,accompanied by surface spalling and debris splashing.Moreover,the thermal shock damage evolution and coupled failure mechanism of tested granite are discussed.The evolution of thermal shock damage with thermal shock cycle numbers shows an obvious S-shaped surface,featured by an exponential correlation with dynamic mechanical parameters.In addition,with increasing thermal shock temperature and cycles,granite mineral species barely change,but the length and width of thermal cracks increase significantly.The non-uniform expansion of minerals,thermal shock-induced cracking,and water-rock interaction are primary factors for deteriorating dynamic mechanical properties of granite under cyclic thermal shock.展开更多
基金Supported by the National Natural Science Foundation of China(12001424,12271324)the Natural Science Basic research program of Shaanxi Province(2021JZ-21)+1 种基金the China Postdoctoral Science Foundation(2020M673332)Xi’an University,Xi’an Science and Technology Plan Wutongshu Technology Transfer Action Innovation Team(25WTZD07)。
文摘In this article,by employing the Hirota bilinear approach and the long wave limit method,we not only derive soliton solutions,lump solutions,and hybrid solutions for the(2+1)-dimensional Yu-Toda-Sasa-Fukuyama(YTSF)equation,but also analyze the dynamical behaviors of nonlinear local wave propagation in shallow water.Firstly,based on the Hirota bilinear approach,one to four-order soliton solutions of the YTSF equation are obtained,and the effects of different parameters on the amplitude,propagation trajectory,and displacement of solitons are investigated.Secondly,using the long wave limit approach,one to three-order lump solutions and various physical quantities of the YTSF equation are derived.It is found that the real and imaginary parts of the parameter pi dominate the propagation trajectory and the shape of lump waves,respectively.Furthermore,we construct the hybrid solution for the YTSF equation,leading to the conclusion that the interaction between lumps and solitons constitutes an elastic collision.To intuitively understand the dynamic behaviors of these solutions,we conduct numerical simulations to present vivid three-dimensional visualizations.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2023-NR076968)the Chung-Ang University Graduate Research Scholarship in 2024.
文摘Background:Adolescent suicide remains a pressing public health concern in South Korea and worldwide,ranking as one of the leading causes of death among youth.Identifying modifiable risk and protective factors is critical for prevention strategies.Physical activity has been suggested as one such factor due to its potential mental health benefits.This study aimed to examine whether associations between physical activity and suicidality differ by activity type and by stage of suicidal behavior,distinguishing suicidal ideation,planning,and attempts among Korean adolescents.Methods:This cross-sectional secondary analysis used data from the 20th Korea Youth Risk Behavior Web-based Survey(KYRBS)conducted in 2024,a nationally representative survey of Korean adolescents.The study included 54,653 middle and high school students with complete data on physical activity,suicidal ideation,planning,and attempts.Three types of physical activity(vigorous activity,muscle-strengthening activity,and≥60 min of daily physical activity)were examined.Associations with suicidal behaviors were analyzed using multivariable logistic regression models,adjusting for psychological,behavioral,and sociodemographic covariates.Results:In this nationally representative sample of Korean adolescents,engaging in at least 60 min of daily physical activity was significantly associated with lower odds of suicide planning,but not ideation or attempts.In contrast,muscle-strengthening activity was linked to increased odds of both suicide planning and attempts,whereas vigorous activity showed no significant associations.Psychological factors,including generalized anxiety,sadness,stress,and loneliness,showed strong associations with suicidal behaviors and were included as covariates in the adjusted models.Female students,low academic performance,and unstable residential status were also associated with higher odds of suicidal behaviors.Conclusion:The associations between physical activity and suicidality differed by activity type and suicidal outcome;muscle-strengthening activity was positively associated with suicide planning and attempts in adjusted models.
文摘Objective: To analyze the impact of motivational nursing under the solution-focused approach on health behaviors in surgical care for bladder cancer patients. Methods: A sample of 72 bladder cancer patients who underwent surgical treatment from September 2024 to September 2025 was randomly divided into groups using a random number table. Group A received motivational nursing under the solution-focused approach, while Group B received conventional nursing. Health behavior scores and complication indicators were compared between the two groups. Results: Group A had higher scores on the Health-Promoting Lifestyle Profile II (HPLP-Ⅱ) than Group B, with p < 0.05. The postoperative complication rate in Group A was lower than that in Group B, with p < 0.05. Conclusion: For bladder cancer patients undergoing surgery, receiving motivational nursing under the solution-focused approach can improve health behaviors, alleviate negative emotions, and is highly feasible and effective.
基金supported by the National Natural Science Foundation of China(Grant No.42171135)the Science and Technology Program of CNOOC Research Institute(Grant No.2023OTKK03)the“CUG Scholar”Scientific Research Funds at China University of Geosciences(Project No.2022098).
文摘The volume change behavior of natural gas hydrate-bearing sediment is essential as it influences settlement,strength,and stiffness,which directly affect the stability of hydrate reservoirs during hydrate extraction or in response to environmental changes.The volume change is influenced not only by stress but also by the formation and dissociation of hydrates.This study adopted a customized apparatus for one-dimensional compression tests,allowing independent control of gas pressure and effective stress.Tests were conducted on samples with different hydrate saturations along various temperature-gas pressure-effective stress paths,yielding some conclusions related to compressibility and creep.An unusual phenomenon was observed under low-stress conditions:hydrate formation led to shrinkage rather than expansion.Three potential mechanisms behind this occurrence were discussed.As hydrate saturation increases,the yield stress rises while the compression and swelling indexes remain minimally affected.After hydrate dissociation,the compression curve of hydrate-bearing sediment drops to that of hydrate-free sediment.Once hydrate is formed,the compression curve of hydrate-free sediment gradually approaches that of hydrate-bearing sediment during the subsequent loading.Under low-stress conditions,the creep of both hydrate-free and hydrate-bearing sediments is very weak.However,when stress increases,significantly beyond the yield stress,the creep of both sediments increases significantly,with hydrate-bearing sediment exhibiting much greater creep than hydrate-free sediment.
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.
文摘Objectives:24-h movement behaviors(24-HMB),encompassing physical activity,sedentary behavior,and sleep duration,are increasingly regarded as interrelated and important factors for mental health.However,evidence on the comprehensive association of these behaviors with mental health in adults with diabetes in developing countries remains scarce.This study examined the association between 24-HMB guidelines and psychological health among adults with diabetes in developing countries.Methods:Data were retrieved from the World Health Organization’s study on Global Aging and Adult Health Survey dataset.Adults(N=1905)diagnosed with diabetes from five low-and middle-income countries were included.The exposure of interest was adherence to 24-HMB guidelines,depression,cognition,and quality of life(QoL).Multiple logistic and multiple linear regression analyses were used to examine the association between meeting 24-HMB guidelines and depression,cognition,and QoL,respectively.Results:This cross-sectional study revealed that 28.61%complied with all three 24-HMB guidelines.Diabetic patients who met more numbers of 24-HMB guidelines had lower depression risk(OR=0.74,95%CI:0.61 to 0.91,p=0.004),greater cognition(β=0.42,95%CI:0.25 to 0.60,p<0.001),and QoL(β=1.30,95%CI:1.04 to 1.55,p<0.001)with the non-compliant population.For specific combinations,meeting all three guidelines were significantly associated with lower odds of depression,improved cognitive function,and enhanced QoL(all p<0.001).Conclusion:These findings support that meeting 24-HMB guidelines in a single or combined movement behaviors was significantly related to reduced risk of depression,enhanced cognitive function,and improved QoL among individuals with diabetes.
基金supported by the National Natural Science Foundation of China(No.52271101)Suzhou Science and Technology Project,China(Nos.SYG202312,SJC2023005,SZS2023023)+1 种基金Nanjing Major Science and Technology Project,China(No.202309015)the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology,China(No.ASMA202305)。
文摘To investigate the aging mechanisms and elucidate the correlations between unstable microstructure and performance in biodegradable Zn alloys,the accelerated aging experiment was conducted on a high-performance wrought Zn−0.1Mg alloy by annealing at 200℃ for varying durations.The findings reveal that the tensile strength of the alloy rapidly and significantly declines with prolonged annealing time,decreasing from 383 MPa for the as-received alloy to 102 MPa for the alloy subjected to 1440 min of annealing.The primary factors contributing to this considerable reduction in strength are static recrystallization,grain coarsening,and dislocation annihilation.Initially,the ductility of the alloy shows fluctuations,ultimately experiencing a marked decrease after extended annealing.This decline is linked to the grain growth and heightened texture intensity,while the unusual increase in ductility observed between 30 and 120 min of annealing is likely due to the formation of twins.In addition,due to rapid grain growth and an increase in precipitates and twins,the corrosion resistance of the alloy in Hank’s solution has worsened,with the corrosion rate rising from 0.037 to 0.069 mm/a following 300 min of annealing.
基金supported by National Special Program for Science&Technology Basic Resources Investigation of China(Grant No.2017GFY101100).
文摘Objective This study aimed to describe 24-hour movement behaviors,including physical activity,sedentary behavior,and sleep period,among Chinese preschoolers using nationally representative data,and examine disparities by age,gender,and residence.Methods A cross-sectional analysis was conducted using data from the China National Nutrition and Health Systematic Survey for Children(2019–2021),including 10,935 children aged 3–5 years.Daily total time of physical activity(TPA),total time of sedentary behaviors(TSB),and total sleep period(TSP)was collected via validated structured questionnaires.Physical inactivity was defined as<180 minutes of TPA per day.Results Median TPA was 121.4(IQR:71.4−209.6)minutes/day,and TSB was 231.4(IQR:175.0−304.3)minutes/day,with 11.46±1.00 hours/day average TSP.Overall,68.8%were physically inactive,with higher prevalence in rural(73.3%)versus urban areas(64.8%,P<0.001).TPA and TSB increased with age,while TSP decreased(all P<0.001).No significant gender differences were observed.Conclusion Most Chinese preschoolers exhibit insufficient physical activity and excessive sedentary behaviors,with notable urban–rural disparities and an escalating trend of ageing.Continuous monitoring and targeted interventions,especially in rural areas,are urgently needed.
文摘Healthy behavior has long been linked to mental health outcomes.However,the role of artificial intelligence(AI)literacy in shaping healthy behaviors and its potential impact on mental health remains underexplored.This paper presents a scoping review offering a novel perspective on the intersection of healthy behaviors,mental health,and AI literacy.By examining how individuals’understanding of AI influences their choices regarding nutrition and their susceptibility to mental health issues,the current study explores emerging trends in health behavior decision-making.This emphasizes the need for integrating AI literacy into mental health and health behaviors education,as well as the development of AI-driven tools to support healthier behavior choices.It highlights that individuals with low AI literacy may misinterpret or overly depend on AI guidance,resulting in maladaptive health choices,while those with high AI literacy may be more likely to engage reflectively and sustain positive behaviors.The paper outlines the importance of inclusive education,user-centered design,and community-based support systems to enhance AI literacy for digitally marginalized groups.AI literacy may be positioned as a key determinant of health equity,better allowing for interdisciplinary strategies that empower individuals to make informed,autonomous decisions that promote both physical and mental health.
基金the funds of the National Natural Science Fund for Excellent Young Scholars of China(No.52222410)Shaanxi Province National Science Fund for Distinguished Young Scholars,China(No.2022JC-24)the National Natural Science Foundation of China(Nos.52227807,52034005)。
文摘A fine-grained metastable dual-phase Fe_(40)Mn_(20)Co_(20)Cr_(15)Si_(5)high entropy alloy(CS-HEA)with excellent strength and ductility was successfully prepared by friction stir processing(FSP).The microstructural and mechanical properties of the fine-grained CS-HEA were characterized.The results showed that as-cast shrinkage cavities and elemental segregation were eliminated.The average grain size was refined from 121.1 to 5.4μm.The face-centered cubic phase fraction increased from 23%to 82%.During tensile deformation,dislocation slip dominated at strains ranging from 5%to 17%,followed by transformation induced plasticity(TRIP)from 17%to 26%,and twin induced plasticity(TWIP)from 26%to 37%.The yield strength,ultimate tensile strength,and elongation of the fine-grained CS-HEA were 503 MPa,1120 MPa,and 37%,respectively.The strength-ductility synergy of fine-grained CS-HEA was attributed to the combined effects of TRIP,TWIP,dislocation strengthening,and fine-grained strengthening.
基金supported by the 2025 Jiangsu Province Graduate Student Practice Innovation Program(No.SJCX25_1696)the 2024 Changzhou University Educational Research Project(No.GJY2024009).
文摘Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.Current research on the associations between 24-hour movement behaviors(including physical activity,sedentary behavior,and sleep)and depression has largely been confined to examining the effects of single behaviors,overlooking the intrinsic compositional nature and interrelationships among these behaviors.Therefore,it is necessary to investigate the integrated effects of 24-hour movement behaviors on depression in older adults with multimorbidity from a holistic,compositional perspective.Methods:From November 2024 to April 2025,a total of 226 older adult patients with multimorbidity were recruited from a tertiary hospital in Changzhou City.Data were collected using a general information questionnaire,the International Physical Activity Questionnaire–Short Form(IPAQ-SF),the Pittsburgh Sleep Quality Index(PSQI),and the Patient Health Questionnaire-9(PHQ-9).Compositional data analysis and isotemporal substitution models were employed for statistical analysis.Results:The mean daily durations of Light-Intensity Physical Activity(LPA),Moderate-to-Vigorous Physical Activity(MVPA),Sedentary Behavior(SB),and Sleep(SLP)in older adults with multimorbidity were 402.48 min,12.04 min,511.52 min,and 458.68 min,respectively.The prevalence of depressive symptoms was 37.6%.Compositional data analysis revealed that SB was positively associated with depression(βSB=1.005,P=0.006),while SLP was negatively associated with depression(βSLP=−1.736,P<0.001).No statistically significant associations were found between MVPA or LPA and depression(P>0.05).In the 10-minute isotemporal substitution model,replacing SB with any other behavioral component was associated with a decrease in depression scores.Conversely,substituting SLP with either LPA or SB resulted in an increase in depression scores,while substituting SLP with MVPA led to a decrease in depression scores.The dose-response analysis revealed that,among the isotemporal substitution effects,replacing SB with SLP and replacing SLP with MVPA were the substitution pathways associated with the most rapid decline in depression scores,representing the greatest beneficial health effects.Conclusion:The prevalence of depression is notably high among older adults with multimorbidity.Reducing daily sedentary behavior(SB),maintaining adequate sleep(SLP),and increasing moderate-to-vigorous physical activity(MVPA)can improve depressive symptoms and enhance overall health in this population.
基金funded by the Guangzhou Development Zone Science and Technology Project(2023GH02)the University of Macao(MYRG2022-00271-FST)research grants by the Science and Technology Development Fund of Macao(0032/2022/A)and(0019/2025/RIB1).
文摘Accurately recognizing driver distraction is critical for preventing traffic accidents,yet current detection models face two persistent challenges.First,distractions are often fine-grained,involving subtle cues such as brief eye closures or partial yawns,which are easily missed by conventional detectors.Second,in real-world scenarios,drivers frequently exhibit overlapping behaviors,such as simultaneously holding a cup,closing their eyes,and yawning,leading tomultiple detection boxes and degradedmodel performance.Existing approaches fail to robustly address these complexities,resulting in limited reliability in safety critical applications.To overcome these pain points,we propose YOLO-Drive,a novel framework that enhances YOLO-based driver monitoring with EfficientViM and Polarized Spectral–Spatial Attention(PSSA)modules.Efficient ViMprovides lightweight yet powerful global–local feature extraction,enabling accurate recognition of subtle driver states.PSSA further amplifies discriminative features across spatial and spectral domains,ensuring robust separation of concurrent distraction cues.By explicitly modeling fine-grained and overlapping behaviors,our approach delivers significant improvements in both precision and robustness.Extensive experiments on benchmark driver distraction datasets demonstrate that YOLO-Drive consistently out-performs stateof-the-art models,achieving higher detection accuracy while maintaining real-time efficiency.These results validate YOLO-Drive as a practical and reliable solution for advanced driver monitoring systems,addressing long-standing challenges of subtle cue recognition and multi-cue distraction detection.
基金supported by a grant from Department of Science and Technology of Jilin Province,No.20230204039YY(to RC)the Construction Project for Antidepressant Screening Engineering Laboratory of Jilin Province,No.2023C010(to BL).
文摘Preliminary studies on emerging herbal ingredients have highlighted alternative pathways that inflammation and modulate perturbed immunity as valuable strategies for treating depression.Previous studies have shown that 5-O-methylvisammioside,a bioactive compound derived from Saposhnikoviae Radix,possesses excellent anti-inflammatory and antioxidant biological functions,exhibits a neuroprotective effect.The purpose of this study was to explore the targets and signaling pathways of 5-O-methylvisammioside in the potential treatment of major depressive disorder using a combination of network pharmacology analysis and biological experiments.The network pharmacological analysis results indicated that the proto-oncogene tyrosine-protein kinase Src and the nuclear factor kappa B signaling pathway were highly correlated with the treatment of major depressive disorder with 5-O-methylvisammioside.Further experiments indicated that 5-O-methylvisammioside significantly improved lipopolysaccharide-induced depression-like behaviors in mice,ameliorated microglial polarization in the hippocampal CA1 and CA3 regions,and inhibited Src phosphorylation and nuclear factor kappa B pathway activation.The effects of 5-O-methylvisammioside were similar to those of the Src inhibitor PP2.When 5-O-methylvisammioside was administered with PP2,no effects were observed on lipopolysaccharide-induced depression-like behaviors in mice,nuclear factor kappa B pathway proteins,and microglial polarization.These findings indicate that 5-O-methylvisammioside may exert its antidepressant potential by inhibiting Src-mediated activation of the nuclear factor kappa B signaling pathway.Therefore,5-O-methylvisammioside might serve as a promising Chinese herbal medicine for the prevention and treatment of depression.
基金National Basic Research Plan Project of China,No.2023YFC3708303the National Natural Science Foundation of China,No.82241084the High-level Talent in Public Health of Beijing,No.Discipline Leaders-03-29(all to XL).
文摘Long-term exposure to ambient fine particulate matter(PM2.5)may increase the risk of neurotoxicity in human populations.However,research studies on the underlying mechanisms of chronic PM2.5-induced depression-like behaviors,and potential therapeutical strategies,remain scarce.In the present study,after long-term exposure to real-world PM2.5 for 15 weeks,male mice displayed depression-like behaviors,which were revealed using the open field and sucrose preference tests.Mechanistically,chronic PM2.5 exposure promoted astrocytic A1 polarization and disrupted reduction-oxidation balance in the mouse hippocampus.Furthermore,PM2.5-exposed mice displayed pathological damage to hippocampal neurons as well as the inhibition of nuclear factor erythroid 2-related factor 2 signaling.Astrocytic ablation of nuclear factor erythroid 2-related factor 2 exacerbated PM2.5-induced hippocampal neuronal injury in mice via the disruption of astrocyte-to-microglia communication;this finding was confirmed in mice with bilateral and unilateral hippocampal astrocytic Nfe2l2 knockdown.Importantly,the upregulation of nuclear factor erythroid 2-related factor 2 activation by procyanidin significantly ameliorated PM2.5-induced depression-like behaviors through the remodeling of astrocyte-to-microglia communication.Together,our findings shed light on the important role of hippocampal astrocytic nuclear factor erythroid 2-related factor 2 activation for maintaining astrocyte-to-microglia communication,and indicate potential research avenues for therapeutic strategies against PM2.5-induced depresson-like behaviors.
基金financially supported by the National Science and Technology Major Project of China(No.2017-Ⅵ-0008-0078)。
文摘Four powder metallurgy(PM)Ni-based superalloys with different Hf and Ta contents were creep-tested at 650℃ and 970 MPa,700℃ and 770 MPa,and 750℃ and 580 MPa,respectively.The effect of Hf and Ta on creep deformation behaviors of the superalloys was studied from multiple scales by SEM,electron backscatter diffraction(EBSD),and aberration-corrected scanning transmission electron microscope(AC-STEM).The results showed that Hf and Ta suppressed the intergranular fracture and initiation of cracks during the acceleration creep stage,which prolonged the creep rupture time.Hf and Ta inhibited the stacking faults extending and the dislocation climbing and promoted the Suzuki segregation of W during the steady-state creep stage,which reduced the minimum creep rate and delayed the start time of the acceleration creep stage.The Suzuki segregation of Co,Cr,Mo,Ti,Nb,W,and Ta along stacking faults was observed after Hf and Ta addition,leading to the localized phase transformation in the γ′phase,and the stacking fault phase was chemically disordered.This study provided ideas for the composition design of novel PM Ni-based superalloys and theoretical foundations for the combined addition of Hf and Ta.
基金support from the National Natural Science Foundation of China(grant number 52075544)Innovation Funds of Jihua Laboratory(X220971UZ230)+1 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515110649)Funds from Research Platforms of Guangdong Higher Education Institutes(2022ZDJS038).
文摘Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.
基金supported by the National Natu-ral Science Foundation of China(grant Nos.52105315,U20B2031,52075022,52075024,and 52175283)the Natural Science Founda-tion of Beijing Municipality(grant Nos.L248031 and3222013)+1 种基金the State Key Lab of Advanced Welding and Joining,Harbin Institute of Technology(No.AWJ-24M05)the Fundamental Research Funds for the Central Universities(Nos.JKF-20240264 andYWF-22-L-607).
文摘The influence of in-situ precipitation on corrosion behaviors of wire arc directed energy deposited (WADED) Al-Mg-(Sc-Zr) was studied. WADED Al-Mg showed a homogeneous microstructure with coarse equiaxed grains. WADED Al-Mg-Sc-Zr exhibited fine equiaxed grains along the molten pool boundary (MPB) and inter-layer zone (ITZ) while coarse equiaxed grains were inside the molten pool. The in-situ precipitation resulted in the primary Al_(3)(Sc, Zr) aggregated along MPB and ITZ while minor-sized secondary Al_(3)(Sc, Zr) existed inside the molten pool. WADED Al-Mg-Sc-Zr showed improved electrochemical behavior than Al-Mg. WADED Al-Mg presented random pittings that occurred near dispersed β-Al_(3)Mg_(2). WADED Al-Mg-Sc-Zr exhibited pittings along MPB and ITZ, where Al_(3)(Sc, Zr) aggregated and induced galvanic corrosion. Corrosion anisotropy was obvious in Al-Mg-Sc-Zr since more MPBs and ITZs make the XOZ plane susceptive to localized corrosion.
文摘This study aims to explore the characteristics of novice teachers’inappropriate behaviors in classroom teaching and their intervention strategies.With the continuous improvement of education quality,novice teachers face increasing challenges in teaching practice.Their inappropriate behaviors not only affect the classroom atmosphere but may also negatively impact students’learning outcomes.Therefore,researching the characteristics of novice teachers’inappropriate behaviors and their intervention strategies holds significant scientific and social value.This study employs a combination of quantitative and qualitative methods to analyze the behavioral patterns of novice teachers in classroom teaching and proposes corresponding intervention strategies.The results indicate that novice teachers’inappropriate behaviors mainly manifest as poor classroom management,monotonous teaching methods,and insufficient interaction with students.Based on these findings,the study proposes a series of effective intervention strategies,including enhancing teacher training,optimizing teaching design,and promoting positive interactions between teachers and students.The conclusions of the study not only provide practical guidance for educational practice but also point out directions for future research,emphasizing the crucial role of teacher professional development in improving teaching quality.
基金financially supported by the State Administration for Market Regulation,China(No.2021MK050)the National Natural Science Foundation of China(Nos.50971043,51171046,21973012)+3 种基金the Key Research and Development Program of China(Nos.2022YFB3807200,CISRI-21T62450ZD)the Natural Science Foundation of Fujian Province,China(Nos.2021J01590,2020J01351,2018J01754,2020J01474)the Student Research and Training Program(SRTP) of Fuzhou University,China(No.29320)Fujian Provincial Department of Science & Technology,China(No.2021H6011)。
文摘In order to understand the influence of ordering behaviors on the thermodynamic and mechanical properties of multi-principal element alloys(MPEAs),the temperature-dependent thermodynamic properties and mechanical properties of FCC_CoNiV MPEAs were comparatively predicted,where the alloys were modeled as the ordered configurations based on our previously predicted site occupying fractions(SOFs),as well as disordered configuration based on traditional special quasi-random structure(SQS).The ordering behavior not only improves the thermodynamic stability of the structure,but also increases the elastic properties and Vickers hardness.For example,at 973 K,the predicted bulk modulus(B),shear modulus(G),Young’s modulus(E),and Vickers hardness(HV)of FCC_CoNiV MPEA based on SOFs configuration are 187.82,79.03,207.93,and 7.58 GPa,respectively,while the corresponded data are 172.58,57.45,155.14,and 4.64 GPa for the SQS configuration,respectively.The Vickers hardness predicted based on SOFs agrees considerably well with the available experimental data,while it is underestimated obviously based on SQS.
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.52225904 and 52039007)the Natural Science Foundation of Sichuan Province(Grant No.2023NSFSC0377)supported by the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘Exploring dynamic mechanical responses and failure behaviors of hot dry rock(HDR)is significant for geothermal exploitation and stability assessment.In this study,via the split Hopkinson pressure bar(SHPB)system,a series of dynamic compression tests were conducted on granite treated by cyclic thermal shocks at different temperatures.We analyzed the effects of cyclic thermal shock on the thermal-related physical and dynamic mechanical behaviors of granite.Specifically,the P-wave velocity,dynamic strength,and elastic modulus of the tested granite decrease with increasing temperature and cycle number,while porosity and peak strain increase.The degradation law of dynamic mechanical properties could be described by a cubic polynomial.Cyclic thermal shock promotes shear cracks propagation,causing dynamic failure mode of granite to transition from splitting to tensile-shear composite failure,accompanied by surface spalling and debris splashing.Moreover,the thermal shock damage evolution and coupled failure mechanism of tested granite are discussed.The evolution of thermal shock damage with thermal shock cycle numbers shows an obvious S-shaped surface,featured by an exponential correlation with dynamic mechanical parameters.In addition,with increasing thermal shock temperature and cycles,granite mineral species barely change,but the length and width of thermal cracks increase significantly.The non-uniform expansion of minerals,thermal shock-induced cracking,and water-rock interaction are primary factors for deteriorating dynamic mechanical properties of granite under cyclic thermal shock.
