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Microstructures and micromechanical behaviors of high -entropy alloys investigated by synchrotron X-ray and neutron diffraction techniques: A review 被引量:1
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作者 Yubo Huang Ning Xu +3 位作者 Huaile Lu Yang Ren Shilei Li Yandong Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第6期1333-1349,共17页
High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Exten... High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed. 展开更多
关键词 high-entropy alloys MICROSTRUCTURES micromechanical behaviors synchrotron X-ray diffraction neutron diffraction
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Snap-through behaviors and nonlinear vibrations of a bistable composite laminated cantilever shell:an experimental and numerical study 被引量:2
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作者 Lele REN Wei ZHANG +1 位作者 Ting DONG Yufei ZHANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期779-794,共16页
The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.... The snap-through behaviors and nonlinear vibrations are investigated for a bistable composite laminated cantilever shell subjected to transversal foundation excitation based on experimental and theoretical approaches.An improved experimental specimen is designed in order to satisfy the cantilever support boundary condition,which is composed of an asymmetric region and a symmetric region.The symmetric region of the experimental specimen is entirely clamped,which is rigidly connected to an electromagnetic shaker,while the asymmetric region remains free of constraint.Different motion paths are realized for the bistable cantilever shell by changing the input signal levels of the electromagnetic shaker,and the displacement responses of the shell are collected by the laser displacement sensors.The numerical simulation is conducted based on the established theoretical model of the bistable composite laminated cantilever shell,and an off-axis three-dimensional dynamic snap-through domain is obtained.The numerical solutions are in good agreement with the experimental results.The nonlinear stiffness characteristics,dynamic snap-through domain,and chaos and bifurcation behaviors of the shell are quantitatively analyzed.Due to the asymmetry of the boundary condition and the shell,the upper stable-state of the shell exhibits an obvious soft spring stiffness characteristic,and the lower stable-state shows a linear stiffness characteristic of the shell. 展开更多
关键词 bistable composite laminated cantilever shell snap-through behavior nonlinear vibration nonlinear stiffness characteristic chaos and bifurcation
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Impact of parenting styles on preschoolers’behaviors 被引量:1
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作者 Elif Sarac 《World Journal of Clinical Cases》 SCIE 2024年第23期5294-5298,共5页
In this editorial,I comment on the article“Association of preschool children behavior and emotional problems with the parenting behavior of both parents”which was published in the latest issue of“World Journal of C... In this editorial,I comment on the article“Association of preschool children behavior and emotional problems with the parenting behavior of both parents”which was published in the latest issue of“World Journal of Clinical Cases”that demonstrates the prevalence of behavioral disorders in preschool children.Therefore I am focused on parenting which is the most effective factor shown to affect the development and continuity of these behaviors.The management of child behavior problems is crucial.Children in early ages,especially preschoolers who are in the first 5 years of life,are influenced by dramatic changes in various aspects of development,such as social,emotional,and physical.Also,children experience many changes linked to different developmental tasks,such as discovering themselves,getting new friendships,and adapting to a new environment.In this period,parents have a critical role in supporting child development.If parents do not manage and overcome their child’s misbehavior,it could be transformed into psychosocial problems in adulthood.Parenting is the most powerful predictor in the social development of preschool children.Several studies have shown that to reduce the child’s emotional and behavioral problems,a warm relationship between parents and children is needed.In addition,recent studies have demonstrated significant relationships between family regulation factors and parenting,as well as with child behaviors. 展开更多
关键词 behavioral problems CHILDREN Emotional problems Parenting style PRESCHOOL
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Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution 被引量:1
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作者 Jia Liu Shuanglu Duan +1 位作者 Xiaokang Yue Ningsong Qu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期750-763,共14页
The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an effici... The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ alloy.In ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the materials.In this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are discussed.The open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are analyzed.The results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ alloy.Moreover,the dissolved surface morphology of the two titanium-based alloys under different current densities are analyzed.Under low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb structure.Under high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy surface.Finally,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed. 展开更多
关键词 electrochemical machining dissolution behavior β-CEZ titanium alloy polarization curve current efficiency
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A thermo-mechanical damage constitutive model for deep rock considering brittleness-ductility transition characteristics
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作者 FENG Chen-chen WANG Zhi-liang +2 位作者 WANG Jian-guo LU Zhi-tang LI Song-yu 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2379-2392,共14页
This paper developed a statistical damage constitutive model for deep rock by considering the effects of external load and thermal treatment temperature based on the distortion energy.The model parameters were determi... This paper developed a statistical damage constitutive model for deep rock by considering the effects of external load and thermal treatment temperature based on the distortion energy.The model parameters were determined through the extremum features of stress−strain curve.Subsequently,the model predictions were compared with experimental results of marble samples.It is found that when the treatment temperature rises,the coupling damage evolution curve shows an S-shape and the slope of ascending branch gradually decreases during the coupling damage evolution process.At a constant temperature,confining pressure can suppress the expansion of micro-fractures.As the confining pressure increases the rock exhibits ductility characteristics,and the shape of coupling damage curve changes from an S-shape into a quasi-parabolic shape.This model can well characterize the influence of high temperature on the mechanical properties of deep rock and its brittleness-ductility transition characteristics under confining pressure.Also,it is suitable for sandstone and granite,especially in predicting the pre-peak stage and peak stress of stress−strain curve under the coupling action of confining pressure and high temperature.The relevant results can provide a reference for further research on the constitutive relationship of rock-like materials and their engineering applications. 展开更多
关键词 deep rock crack initiation threshold thermo-mechanical coupling statistical damage model distortion energy theory
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The Impact of Social Media on Dietary Behaviors and Body Image of College Students: A Qualitative Approach
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作者 Basem Azmy Saad Boutros Tabbetha D. Lopez Valencia Browning-Keen 《Food and Nutrition Sciences》 CAS 2024年第8期711-726,共16页
Background: The use of social media platforms for health and nutrition information has become popular among college students. Although social media made information readily accessible in different formats, nutritional... Background: The use of social media platforms for health and nutrition information has become popular among college students. Although social media made information readily accessible in different formats, nutritional misinformation promoted by influencers and non-experts caused negative impact on diet behavior and perception of body image. Previous research indicated that extensive use of social media was positively linked to disordered eating behaviors. Social media platforms like Facebook and Instagram that allow users to follow celebrities intensified exposure to influencers’ messages and images and resulted in negative moods and body dissatisfaction. Objective: This paper aims to explore the impact of social media on college students’ dietary behaviors and body image. Participants: 18 undergraduate students from a public university in the Southern United States were recruited through a mass email. Methods: A cross-sectional qualitative study of three focus groups was conducted. The focus groups were based on guiding open-ended questions. Atlas.ti was used to code and analyze the data using inductive and deductive codes. Results: Three main themes were identified. The conditions theme included elements that explain why and how social media influences the participants’ actions. The actions theme included eating behavior, physical activity, and dietary supplement intake. The consequences theme describes anticipated or actual outcomes of actions such as body image and ideal weight. Conclusions: Social media has had a negative influence on diet behaviors and a positive influence on physical activity. Evidence-based nutrition and weight management information is needed to thwart potential misinformation. 展开更多
关键词 Social Media Nutrition Information Dietary behavior Body Image College Students
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Xylooligosaccharides Alleviate Inflammatory Dermatoses and Related Depression-Like Behaviors in Atopic Dermatitis Mice Induced by 2,4-Dinitrofluorobenzene
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作者 FANG Mingyu TANG Liu +6 位作者 LI Zimo NIE Tingting CHEN Shaoze FANG Zhenfeng SHI Lu HU Song CAO Xiaoqin 《食品科学》 EI CAS CSCD 北大核心 2024年第17期113-126,共14页
Objective:To investigate the influence of xylooligosaccharides on skin inflammation,behavioral characteristics,neurotransmitters,and gut flora in a mouse model of atopic dermatitis(AD)induced by 2,4-dinitrofluorobenze... Objective:To investigate the influence of xylooligosaccharides on skin inflammation,behavioral characteristics,neurotransmitters,and gut flora in a mouse model of atopic dermatitis(AD)induced by 2,4-dinitrofluorobenzene(DNFB).Methods:The AD mouse model was created by administration of DNFB for 14 consecutive days.The scoring atopic dermatitis index,enzyme-linked immunosorbent assay(ELISA),histopathology,and immunohistochemical analyses were used to assess inflammation and depression-like behaviors.Furthermore,high-throughput 16S rRNA gene sequencing was used to determine the composition of fecal microbiota.Results:Xylooligosaccharides treatment reduced the number of scratches and skin thickness,mast cell infiltration and the levels of immunoglobulin(Ig)E and T-helper cytokines compared with the AD model group.Meanwhile,xylooligosaccharides treatment reduced the immobility time of mice in the forced swimming test and increased the total movement distance and movement distance in the center area in the open-field test.Furthermore,5-hydroxytryptamine and dopamine expression in the brain was increased following xylooligosaccharides treatment.Using network pharmacology,Gene Ontology analysis showed that the targets were mainly enriched in phosphatase binding and the regulation of leukocyte differentiation,which ameliorated AD mainly through the hypoxia inducible factor-1 and phosphatidylinositide 3-kinase-protein kinase B pathways.16S rRNA gene sequencing,diversity indices,and gut microbial taxonomic composition analysis showed DNFB-induced changes in intestinal microbiota diversity in AD mice.Comparative analysis indicated that xylooligosaccharides intake improved the gut microbiome by dramatically enhancing the concentration of Lactobacillus while decreasing the concentration of Bacteroides in mice.Conclusion:Xylooligosaccharides reduce inflammatory dermatosis and related depression-like behaviors via regulating intestinal homeostasis,having medicinal value as a nutritional and functional ingredient. 展开更多
关键词 atopic dermatitis intestinal flora XYLOOLIGOSACCHARIDES depression-like behaviors
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MD Simulation of Diffusion Behaviors in Collision Welding Processes of Al-Cu, Al-Al, Cu-Cu
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作者 Dingyi Jin Guo Wei 《Computers, Materials & Continua》 SCIE EI 2024年第6期3455-3468,共14页
To investigate the effects of material combinations and velocity conditions on atomic diffusion behavior near collision interfaces,this study simulates the atomic diffusion behavior near collision interfaces in Cu-Al,... To investigate the effects of material combinations and velocity conditions on atomic diffusion behavior near collision interfaces,this study simulates the atomic diffusion behavior near collision interfaces in Cu-Al,Al-Al and Cu-Cu combinations fabricated through collision welding using molecular dynamic(MD)simulation.The atomic diffusion behaviors are compared between similar metal combinations(Al-Al,Cu-Cu)and dissimilar metal combinations(Al-Cu).By combining the simulation results and classical diffusion theory,the diffusion coefficients for similar and dissimilar metal material combinations under different velocity conditions are obtained.The effects of material combinations and collision velocity on diffusion behaviors are also discussed.The diffusion behaviors of dissimilar material combinations strongly depend on the transverse velocity,whereas those of the similar material combinations are more dependent on the longitudinal velocity.These findings can provide guidance for optimizing welding parameters. 展开更多
关键词 Atomic diffusion behavior molecular dynamics collision welding
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Dietary L-proline supplementation ameliorates autism-like behaviors and modulates gut microbiota in the valproic acid-induced mouse model of autism spectrum disorder
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作者 Jingjing Fang Ruixuan Geng +2 位作者 Seong-Gook Kang Kunlun Huang Tao Tong 《Food Science and Human Wellness》 SCIE CAS CSCD 2024年第5期2889-2905,共17页
The effective intervention strategy for autism spectrum disorder(ASD)are currently limited.Herein,we attempted to evaluate the potential of L-proline(Pro),a multifunctional amino acid,in ameliorating autismlike behavi... The effective intervention strategy for autism spectrum disorder(ASD)are currently limited.Herein,we attempted to evaluate the potential of L-proline(Pro),a multifunctional amino acid,in ameliorating autismlike behaviors and clarify the molecular mechanisms involved by using the typical valproic acid(VPA)-induced mouse model of ASD.Pro significantly attenuates repetitive behaviors and social dysfunction in ASD mice.The correlation analysis revealed that the beneficial effects of Pro on autism-like behaviors are related to the modulation of gut microbiota structure and composition.The histological analysis revealed that Pro could reverse the decrease of Nissl-positive cells in the prefrontal cortex(PFC)induced by VPA exposure.RNA sequencing demonstrated that Pro can also alter the PFC transcriptomic profile distinguished by the regulation of genes involved in Parkinson disease,neuroactive ligand-receptor interaction,oxidative phosphorylation,and mitogen activated protein kinase signaling pathway.Overall,dietary Pro supplementation may be a promising intervention strategy for ASD. 展开更多
关键词 L-PROLINE Autism spectrum disorder Gut microbiota Prefrontal cortex behavior
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Liquefaction and post-liquefaction behaviors of sands affected by immersion-induced degradation of crushed mudstone
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作者 Tadao Enomoto 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1799-1812,共14页
A series of undrained triaxial tests was conducted to investigate the effect of crushed mudstone with the immersion-induced degradation on the liquefaction and post-liquefaction properties,and the undrained shearing b... A series of undrained triaxial tests was conducted to investigate the effect of crushed mudstone with the immersion-induced degradation on the liquefaction and post-liquefaction properties,and the undrained shearing behavior without precedent cyclic-loading histories of sands containing crushed mudstone.The tested materials with a main particle diameter of 2-0.85 mm were prepared by mixing sands and crushed mudstone to reach the prescribed mudstone content defined by dry mass ranging from 0% to 50%.The mixtures were subjected to immersion under a certain stress level and were subsequently tested.In addition,one-dimensional compression tests were also supplementally performed to visually observe the immersion-induced degradation of crushed mudstone.The test results mainly showed that: (1) the liquefaction resistance,the post-liquefaction undrained strength,and the undrained strength without a precedent cyclic-loading history decreased significantly with increasing mudstone content,M c ,up to 20%;(2) even a small amount of crushed mudstone affected these strengths;(3) the above-mentioned large reductions in the strengths were attributed to the immersion-induced degradation of crushed mudstone;(4) at M_(c) >20%,the liquefaction resistance increased while the significant increase in the undrained static strengths with and without precedent cyclic-loading histories was not observed;and (5) the increase in the liquefaction resistance at M_(c) >20% may have been attributed to both the gradual increase in the plasticity and the formation of the soil aggregates among deteriorated crushed mudstone,while the increase in the specimen density did not play an important role in such behavior. 展开更多
关键词 LIQUEFACTION Post-liquefaction behavior Triaxial test Sands containing crushed mudstone
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Finite Element Simulations on Failure Behaviors of Granular Materials with Microstructures Using a Micromechanics-Based Cosserat Elastoplastic Model
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作者 Chenxi Xiu Xihua Chu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2305-2338,共34页
This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials.By utilizing this model,the macroscopic constitutive parameters of granular materials with different microstru... This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials.By utilizing this model,the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural information.The microstructures under consideration can be classified into three categories:a medium-dense microstructure,a dense microstructure consisting of one-sized particles,and a dense microstructure consisting of two-sized particles.Subsequently,the Cosserat elastoplastic model,along with its finite element formulation,is derived using the extended Drucker-Prager yield criteria.To investigate failure behaviors,numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element(UEL)interface.It demonstrates the capacity of the proposed model to simulate the phenomena of strain-softening and strain localization.The study investigates the influence of microscopic parameters,including contact stiffness parameters and characteristic length,on the failure behaviors of granularmaterials withmicrostructures.Additionally,the study examines themesh independence of the presented model and establishes its relationship with the characteristic length.A comparison is made between finite element simulations and discrete element simulations for a medium-dense microstructure,revealing a good agreement in results during the elastic stage.Somemacroscopic parameters describing plasticity are shown to be partially related to microscopic factors such as confining pressure and size of the representative volume element. 展开更多
关键词 Granular materials MICROMECHANICS Cosserat elastoplastic model MICROSTRUCTURES failure behaviors
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Thermally-induced cracking behaviors of coal reservoirs subjected to cryogenic liquid nitrogen shock
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作者 Songcai Han Qi Gao +5 位作者 Xinchuang Yan Lile Li Lei Wang Xian Shi Chuanliang Yan Daobing Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期2894-2908,共15页
The benefits of using cryogenic liquid nitrogen shock to enhance coal permeability have been confirmed from experimental perspectives.In this paper,we develop a fully coupled thermo-elastic model in combination with t... The benefits of using cryogenic liquid nitrogen shock to enhance coal permeability have been confirmed from experimental perspectives.In this paper,we develop a fully coupled thermo-elastic model in combination with the strain-based isotropic damage theory to uncover the cooling-dominated cracking behaviors through three typical cases,i.e.coal reservoirs containing a wellbore,a primary fracture,and a natural fracture network,respectively.The progressive cracking processes,from thermal fracture initiation,propagation or cessation,deflection,bifurcation to multi-fracture interactions,can be well captured by the numerical model.It is observed that two hierarchical levels of thermal fractures are formed,in which the number of shorter thermal fractures consistently exceeds that of the longer ones.The effects of coal properties related to thermal stress levels and thermal diffusivity on the fracture morphology are quantified by the fracture fractal dimension and the statistical fracture number.The induced fracture morphology is most sensitive to changes in the elastic modulus and thermal expansion coefficient,both of which dominate the complexity of the fracture networks.Coal reservoir candidates with preferred thermal-mechanical properties are also recommended for improving the stimulation effect.Further findings are that there exists a critical injection temperature and a critical in-situ stress difference,above which no thermal fractures would be formed.Preexisting natural fractures with higher density and preferred orientations are also essential for the formation of complex fracture networks.The obtained results can provide some theoretical support for cryogenic fracturing design in coal reservoirs. 展开更多
关键词 Coal reservoirs Cryogenic shock Thermal cracking behaviors Fracture morphology
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Integrating linear and nonlinear models to assess the built environment’s impact on older adults’behaviors in China
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作者 Xiaoping Wang Zeyan Li +2 位作者 Fang Wu Meng Zhang Hongyong Liu 《Chinese Journal of Population,Resources and Environment》 2024年第2期146-156,共11页
China is experiencing rapid population aging.The one contributing factor affecting senior citizens’lives is the disconnect between the built environment in urban and rural areas and the behavioral preferences of olde... China is experiencing rapid population aging.The one contributing factor affecting senior citizens’lives is the disconnect between the built environment in urban and rural areas and the behavioral preferences of older adults.However,research on the relation between the built environment and the behavior of older individuals has been limited.Thus,this paper uses the most recent health tracking data on factors influencing aging in China released in 2020(China Senior Health Survey Tracking Survey).Applying traditional regression,least absolute shrinkage and selection operator regression,and two decision tree optimization models from machine learning,a comprehensive comparative study is carried out to investigate the correlation between the built environment and the physical activity,dietary habits,and social interactions of older age groups.The findings reveal that built environment variables most significantly impact physical activity,accounting for 52.525%,followed by social interaction behaviors at 50.202%and dietary intake at 47.991%.Furthermore,the authors identify population density and greenness rate as the built environment factors having considerable effects on the behavior of older adults.Thus,this study establishes a theoretical foundation for developing age-friendly community environments for older adults. 展开更多
关键词 Built environment behavioral activity AGING Machine learning
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Database Search Behaviors: Insight from a Survey of Information Retrieval Practices
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作者 Babita Trivedi Brijender Dahiya +2 位作者 Anjali Maan Rajesh Giri Vinod Prasad 《Intelligent Information Management》 2024年第5期195-218,共24页
This study examines the database search behaviors of individuals, focusing on gender differences and the impact of planning habits on information retrieval. Data were collected from a survey of 198 respondents, catego... This study examines the database search behaviors of individuals, focusing on gender differences and the impact of planning habits on information retrieval. Data were collected from a survey of 198 respondents, categorized by their discipline, schooling background, internet usage, and information retrieval preferences. Key findings indicate that females are more likely to plan their searches in advance and prefer structured methods of information retrieval, such as using library portals and leading university websites. Males, however, tend to use web search engines and self-archiving methods more frequently. This analysis provides valuable insights for educational institutions and libraries to optimize their resources and services based on user behavior patterns. 展开更多
关键词 Information Retrieval Database Search User behavior Patterns
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Mechanical behaviors of mylonitic granite and granitic protomylonite in a deep ductile shear zone
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作者 Lanbin Zhang Ru Zhang +5 位作者 Li Ren Zhilong Zhang Zetian Zhang Dong Wang Xinzhong Wang Huijun Lu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第7期2663-2677,共15页
For projects near the tectonic belt,mylonite of varying metamorphic degrees may be present.The matrix proportion of rock reflects its internal microscopic characteristics,thus it is beneficial for engineering geology ... For projects near the tectonic belt,mylonite of varying metamorphic degrees may be present.The matrix proportion of rock reflects its internal microscopic characteristics,thus it is beneficial for engineering geology to study the effect of the matrix proportion on the mechanical properties and rupture behaviors of rock.Samples of mylonitic granite and granitic protomylonite with varying matrix proportions were obtained from a ductile shear zone for a series of uniaxial compression and acoustic emission(AE)tests.The results showed that with the increase in matrix proportion,the average strength and elastic modulus of the samples increased,and the rock sample with the largest matrix proportion exhibited the maximum peak stress of 244.42 MPa,which was 45.86%greater than the average peak stress of the rock samples with the smallest matrix proportions.For the rock samples with larger matrix proportion,their mechanical parameters exhibited greater dispersion and the large-scale appearance of AE events occurred earlier,showing a relatively gradual failure process.These samples had larger accumulated AE parameter values and greater degree of failure.In contrast,for samples with smaller matrix proportions,the large-scale appearance of AE events occurred close to the peak stress,indicating that the occurrence of damage and fractures was centralized and instantaneous.These samples had lower accumulated AE parameter values and fewer cracks after failure.Additionally,for the rock samples with more matrix proportion,the average variance of the b-value was 1.1,which was lower than that of rock samples with the smallest matrix proportion(the average variance of the b-value was 3.7).Furthermore,it can be predicted that under certain stress,the failure depth around a tunnel is generally smaller when the strength of rock samples with larger matrix proportion is greater. 展开更多
关键词 MYLONITE Matrix proportion Mechanical properties Acoustic emission(AE) Rupture behaviors
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Evidence for the Reliability and Validity of the Arabic Version of the Student Risk Screening Scale for Internalizing and Externalizing Behaviors (SRSS-IE)
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作者 Sumayah A. Alrubayie Keetam D. F. Alkahtani 《Journal of Behavioral and Brain Science》 2024年第1期32-45,共14页
School-based universal screening for behavioral/emotional risk is a necessary first step to providing services in an educational setting for students with emotional and behavioral disorders (EBDs). Psychometric proper... School-based universal screening for behavioral/emotional risk is a necessary first step to providing services in an educational setting for students with emotional and behavioral disorders (EBDs). Psychometric properties are critical to making decisions about choosing a screening instrument. The purpose of the present study was to examine the psychometric properties of the student risk screening scale for internalizing and externalizing behaviors (SRSS-IE). Participants included 3145 students and their teachers. Item-level analyses of the current sample supported the retention of all items. The internal consistency of the SRSS items ranged from 0.83 to 0.85. Convergent validity between the SRSS-IE and a well-established screening tool, the strength and difficulties questionnaire (SDQ), was found for the total score (r = 0.70). Additionally, the results of this study demonstrate strong social validity, suggesting the SRSS-IE to be a useful and functional screening tool. We conclude that the SRSS-IE is a valid and reliable instrument for assessing the level of emotional and behavioral difficulties among elementary students. 展开更多
关键词 The Student Risk Screening Scale for Internalizing and Externalizing behaviors (SRSS-IE) Strength and Difficulties Questionnaire (SDQ) Emotional and behavioral Difficulties Screening Tools Systematic Screening
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Mechanical behaviors of warm and ice-rich frozen soil stabilized with sulphoaluminate cement
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作者 WANG Honglei ZHANG Hu +2 位作者 ZHANG Jianming ZHANG Qi YIN Zhenhua 《Journal of Mountain Science》 SCIE CSCD 2024年第1期335-345,共11页
The warm and ice-rich frozen soil is characterized by high unfrozen water content, low shear strength and large compressibility, which is unreliable to meet the stability requirements of engineering infrastructures an... The warm and ice-rich frozen soil is characterized by high unfrozen water content, low shear strength and large compressibility, which is unreliable to meet the stability requirements of engineering infrastructures and foundations in permafrost regions. In this study, a novel approach for stabilizing the warm and ice-rich frozen soil with sulphoaluminate cement was proposed based on chemical stabilization. The mechanical behaviors of the stabilized soil, such as strength and stress-strain relationship, were investigated through a series of triaxial compression tests conducted at -1.0℃, and the mechanism of strength variations of the stabilized soil was also explained based on scanning electron microscope test. The investigations indicated that the strength of stabilized soil to resist failure has been improved, and the linear Mohr-Coulomb criteria can accurately reflect the shear strength of stabilized soil under various applied confining pressure. The increase in both curing age and cement mixing ratio were favorable to the growth of cohesion and internal friction angle. More importantly, the strength improvement mechanism of the stabilized soil is attributed to the formation of structural skeleton and the generation of cementitious hydration products within itself. Therefore, the investigations conducted in this study provide valuable references for chemical stabilization of warm and ice-rich frozen ground, thereby providing a basis for in-situ ground improvement for reinforcing warm and ice-rich permafrost foundations by soil-cement column installation. 展开更多
关键词 Permafrost regions Frozen soil Mechanical behavior Chemical stabilization Ground improvement Ground modification
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Intrinsic correlation between the generalized phase equilibrium condition and mechanical behaviors in hydrate-bearing sediments
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作者 Jiazuo Zhou Changfu Wei +2 位作者 Rongtao Yan Yuan Zhou Yi Dong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第7期2822-2832,共11页
The phase equilibrium and mechanical behaviors of natural gas hydrate-bearing sediment are essential for gas recovery from hydrate reservoirs.In heating closed systems,the temperature-pressure path of hydrate-bearing ... The phase equilibrium and mechanical behaviors of natural gas hydrate-bearing sediment are essential for gas recovery from hydrate reservoirs.In heating closed systems,the temperature-pressure path of hydrate-bearing sediment deviates from that of pure bulk hydrate,reflecting the porous media effect in phase equilibrium.A generalized phase equilibrium equation was established for hydrate-bearing sediments,which indicates that both capillary and osmotic pressures cause the phase equilibrium curve to shift leftward on the temperature-pressure plane.In contrast to bulk hydrate,hydrate-bearing sediment always contains a certain amount of unhydrated water,which keeps phase equilibrium with the hydrate within the hydrate stability field.With changes in temperature and pressure,a portion of pore hydrate and unhydrated water may transform into each other,affecting the shear strength of hydrate-bearing sediment.A shear strength model is proposed to consider not only hydrate saturation but also the change in temperature and pressure of hydrate-bearing sediment.The model is validated by experimental data with various hydrate saturation,temperature and pressure conditions.The deformation induced by partial dissociation was studied through depressurization tests under constant effective stress.The reduction in gas pressure within the hydrate stability field indeed caused sediment deformation.The dissociation-induced deformation can be reasonably estimated as the difference in volume between hydrate-bearing and hydrate-free sediments from the compression curves. 展开更多
关键词 Hydrate-bearing sediment Generalized phase equilibrium Unhydrated water Partial dissociation Mechanical behavior
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Examining the Hypothesis of Common Factors Shared by Different Addictive Behaviors and Gender Effects on Propensity to Addiction Type
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作者 Masayo Uji Junko Watanabe Toshinori Kitamura 《Open Journal of Medical Psychology》 2024年第3期58-70,共13页
Background: From the two facts reported by previous research: 1) frequent co-occurrence of more than one addictive behavior, 2) childhood adversities identified as origins of different types of addictive behaviors, it... Background: From the two facts reported by previous research: 1) frequent co-occurrence of more than one addictive behavior, 2) childhood adversities identified as origins of different types of addictive behaviors, it is assumed that all types of addictive behaviors, regardless of substance, behavioral, or relationship, share common factors which have not yet been proven by epidemiological research. The Shorter PROMIS Questionnaire (SPQ) was previously developed to assess 16 types of addictive behaviors. Its factor structure, however, has not been fully investigated. Confirming the factor structure will enable us to hypothesize the common factor(s) shared by all, or if not all, most types of addictive behaviors. Aims: This study aimed at 1) examining the factor structure of the SPQ, 2) confirming the reliability of the questionnaire, and 3) examining the impacts of gender and age on each addictive behavior. Methods: Data obtained from 232 Japanese adults who completed all items of the SPQ were used for the analyses. After confirming the one-factor structure model for each of the 16 subscales, the validity of the one-factor structure of the SPQ was evaluated using Confirmatory Factor Analysis (CFA), by adapting 16 subscale scores as observed variables. If its validity was not confirmed, another model which showed better compatibility to the data was explored. The reliability of the SPQ as well as that of all 16 subscales was evaluated. Also, the impacts of gender and age on each subscale score were examined. Results: The one-factor structure for each of the 16 subscales was confirmed. The compatibility of the SPQ one-factor model was not acceptable. The best fit model was a bi-factor model in which one main factor was shared by all 16 subscales, and three factors were shared by some specific addictive behaviors. Male respondents were more likely than female respondents to show high scores in Alcohol, Tobacco, Gambling, Sex, and Recreational Drugs, and low scores only in Shopping. Respondents’ age did not impact any of the 16 subscale scores. Conclusion: It was demonstrated that there are common factors shared by all different types, as well as selected types of addictive behaviors, by conducting CFAs of the SPQ. Reliability was proven for the SPQ and for all 16 subscales. Male respondents were more likely to show physically hedonic addictive behaviors. 展开更多
关键词 Addictive behaviors Shorter PROMIS Questionnaire Confirmatory Factor Analysis
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The aggregation behaviors of organic radicals in polar fluorinated arenes
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作者 Shan Liu Yin Yang Tianfei Liu 《Aggregate》 EI CAS 2024年第4期245-255,共11页
Polarfluorinated arenes can promote organic free radical reactions,which have attracted scientists’interest in recent years.However,it is still unknown how these solvents interact weakly with organic radical molecules... Polarfluorinated arenes can promote organic free radical reactions,which have attracted scientists’interest in recent years.However,it is still unknown how these solvents interact weakly with organic radical molecules to influence their reactiv-ity.In this study,we investigated how organic free radicals aggregate infive polarfluorocarbon solvents,and demonstrated that different substituents can influence their aggregation behaviors.In these solvents,small organic radicals with simple substituents maintain a homogeneous solution;however,radicals with substituents that form intermolecular hydrogen bonds or with long-chain aliphatic hydrocarbons tend to aggregate in them,whereas substituents of long-chain aliphatic hydrocar-bons tend to promote aggregation better.The critical aggregation concentrations of these aggregates are measured by concentration-dependent UV–visible spec-troscopy.Their topological morphologies are all spherical based on TEM.The compactness and rotational motivation speed of radical molecules within these aggregates are determined by EPR spectroscopy.The particle sizes of these aggre-gates are determined by analyzing their cyclic voltammograms.Most excitingly,electrochemical experiments reveal that the aggregation behaviors of free radical molecules with intermolecular hydrogen bonds can significantly increase their cat-alytic rate for electro-oxidizing benzyl alcohol in such a solvent.The results of this study indicate that in polarfluorinated arenes organic radical molecules’aggregation behaviors are related to their structures.This may provide guidelines for regulating organic radical reactivity in these solvents in the future. 展开更多
关键词 aggregation behavior organic radical molecules polarfluorinated arenes
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