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
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
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
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
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
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
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
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
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
High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic ...High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data.展开更多
Objective:This study aimed to examine the causal model of eating behaviors among pregnant women working in industrial factories.Methods:This cross-sectional study was conducted on 210 participants,attending 4 healthca...Objective:This study aimed to examine the causal model of eating behaviors among pregnant women working in industrial factories.Methods:This cross-sectional study was conducted on 210 participants,attending 4 healthcare centers,at a tertiary care hospital in Chonburi province,Thailand.Data were collected using 7 questionnaires:demographic form,eating behavior questionnaire,perceived benefits of the healthy eating questionnaire,perceived barriers to the healthy eating questionnaire,perceived self-efficacy questionnaire,social support questionnaire,and accessibility to healthy foods questionnaire.Descriptive statistics and path analysis were used for data analysis.Results:The participants had relatively high mean scores for eating behaviors.The final model fitted well with the dataχ^(2)=12.86,df=10,P=0.23;χ^(2)/df=1.29;comparative fit index(CFI)=0.98;goodness-of-fit index(GFI)=0.98;adjusted goodness-of-fit index(AGFI)=0.95;root mean square error of approximation(RMSEA)=0.04.Four factors-perceived benefits(β=0.13,P<0.05),perceived self-efficacy in healthy eating(β=0.22,P<0.001),pregnancy planning(β=0.28,P<0.001),and accessibility to healthy foods in the factory(β=0.12,P<0.05)-positively affected eating behavior,while only perceived barriers to healthy eating had a negative effect on eating behavior(β=−0.24,P<0.001).All the above factors explained 27.2%of the variance in eating behaviors.Conclusions:Nurses or healthcare providers can apply these findings to create an eating behavior modification program,focusing on pregnancy planning,behavior-specific variables,and interpersonal and situational influence,to promote the nutritional status of pregnant women working in industrial factories.展开更多
Material removal in the cutting process is regarded as a friction system with multiple input and output variables.The complexity of the cutting friction system is caused by the extreme conditions existing on the tool...Material removal in the cutting process is regarded as a friction system with multiple input and output variables.The complexity of the cutting friction system is caused by the extreme conditions existing on the tool–chip and tool–workpiece interfaces.The critical issue is significant to use knowledge of cutting friction behaviors to guide researchers and industrial manufacturing engineers in designing rational cutting processes to reduce tool wear and improve surface quality.This review focuses on the state of the art of research on friction behaviors in cutting procedures as well as future perspectives.First,the cutting friction phenomena under extreme conditions,such as high temperature,large strain/strain rates,sticking–sliding contact states,and diverse cutting conditions are analyzed.Second,the theoretical models of cutting friction behaviors and the application of simulation technology are discussed.Third,the factors that affect friction behaviors are analyzed,including material matching,cutting parameters,lubrication/cooling conditions,micro/nano surface textures,and tool coatings.Then,the consequences of the cutting friction phenomena,including tool wear patterns,tool life,chip formation,and the machined surface are analyzed.Finally,the research limitations and future work for cutting friction behaviors are discussed.This review contributes to the understanding of cutting friction behaviors and the development of high-quality cutting technology.展开更多
Biomedical degradable materials would be subjected to different degrees and forms of static stress after being implanted in the human body.In this work,the biocorrosion behaviors of AZ31B magnesium alloy under differe...Biomedical degradable materials would be subjected to different degrees and forms of static stress after being implanted in the human body.In this work,the biocorrosion behaviors of AZ31B magnesium alloy under different stress forms with different magnitudes(20~150MPa)were studied.It was found that the corrosion behaviors at stressed conditions were severer than those at unstressed conditions and corrosion rates were obviously accelerated.The biocorrosion behaviors are more sensitive to the effects of tensile loads than to compressive loads.A biocorrosion numerical model on the degradation process of Mg alloy under static loads was established.The corrosion current density(i_(corr))of Mg alloy and the applied static stress(σ)matches a linear relationship of ln i_(corr)~σwell during the early stage(within 24 hrs)while deviated gradually in the latter period of corrosion.This work could provide a guidance and theoretical reference for further researches on the biocorrosion behaviors and practical clinical applications of the biomedical materials subjected to physiological loads.展开更多
Pyrolytic graphite (PG) with highly aligned graphene layers,present anisotropic electrical and thermal transport behavior,which is attractive in electronic,electrocatalyst and energy storage.Such pristine PG could mee...Pyrolytic graphite (PG) with highly aligned graphene layers,present anisotropic electrical and thermal transport behavior,which is attractive in electronic,electrocatalyst and energy storage.Such pristine PG could meeting the limit of electrical conductivity (~2.5×10^(4) S·cm^(−1)),although efforts have been made for achieving high-purity sp^(2) hybridized carbon.For manipulating the electrical conductivity of PG,a facile and efficient electrochemical strategy is demonstrated to enhance electrical transport ability via reversible intercalation/de-intercalation of AlCl_(4)^(-)into the graphitic interlayers.With the stage evolution at different voltages,variable electrical and thermal transport behaviors could be achieved via controlling AlCl_(4)^(-)concentrations in the PG because of substantial variation in the electronic density of states.Such evolution leads to decoupled electrical and thermal transport (opposite variation trend) in the in-plane and out-of-plane directions,and the in-plane electrical conductivity of the pristine PG (1.25×10^(4) S·cm^(−1)) could be massively promoted to 4.09×10^(4) S·cm(AlCl_(4)^(-)intercalated PG),much better than the pristine bulk graphitic papers used for the electrical transport and electromagnetic shielding.The fundamental mechanism of decoupled transport feature and electrochemical strategy here could be extended into other anisotropic conductive bulks for achieving unusual behaviors.展开更多
This paper reviews the major achievements in terms of mechanical behaviors of coal measures,mining stress distribution characteristics and ground control in China’s deep underground coal mining.The three main aspects...This paper reviews the major achievements in terms of mechanical behaviors of coal measures,mining stress distribution characteristics and ground control in China’s deep underground coal mining.The three main aspects of this review are coal measure mechanics,mining disturbance mechanics,and rock support mechanics.Previous studies related to these three topics are reviewed,including the geo-mechanical properties of coal measures,distribution and evolution characteristics of mining-induced stresses,evolution characteristics of mining-induced structures,and principles and technologies of ground control in both deep roadways and longwall faces.A discussion is made to explain the structural and mechanical properties of coal measures in China’s deep coal mining practices,the types and dis-tribution characteristics of in situ stresses in underground coal mines,and the distribution of mining-induced stress that forms under different geological and engineering conditions.The theory of pre-tensioned rock bolting has been proved to be suitable for ground control of deep underground coal roadways.The use of combined ground control technology(e.g.ground support,rock mass modification,and destressing)has been demonstrated to be an effective measure for rock control of deep roadways.The developed hydraulic shields for 1000 m deep ultra-long working face can effectively improve the stability of surrounding rocks and mining efficiency in the longwall face.The ground control challenges in deep underground coal mines in China are discussed,and further research is recommended in terms of theory and technology for ground control in deep roadways and longwall faces.展开更多
Tunnel-type anchorages(TTAs)installed in human gathering areas are characterized by a shallow burial depth,and in many instances,they utilize soft rock as the bearing stratum.However,the stability control measures and...Tunnel-type anchorages(TTAs)installed in human gathering areas are characterized by a shallow burial depth,and in many instances,they utilize soft rock as the bearing stratum.However,the stability control measures and the principle of shallow TTAs in soft rock have not been fully studied.Hence,a structure suitable for improving the stability of shallow TTAs in soft rock strata,named the anti-pull tie(APT),was added to the floor of the back face.Physical tests and numerical models were established to study the influence of the APT on the load transfer of TTAs,the mechanical response of the surrounding rock,the stress distribution of the interface,and the failure model.The mechanical characteristics of APTs were also studied.The results show that the ultimate bearing capacity of TTAs with an APT is increased by approximately 11.8%,as compared to the TTAs without an APT.Also,the bearing capacity of TTAs increases approximately linearly with increasing height,width,length,and quantity of APTs,and decreases approximately linearly with increasing distance from the back face and slope angle of the tie slope.The normal squeezing between the tie slope and the surrounding rock increases the shear resistance of the interface and expands the range of the surrounding rock participating in bearing sharing.Both tension and compression zones exist in the APT during loading.The tension zone extends from the tie toe to the tie bottom along the tie slope.The range of the tie body tension zone constantly expands to the deep part of the APT with an increasing load.The peak tensile stress value is located at the tie toe.The distribution of compressive stress in the tie body is the largest at the tie top,followed by the tie slope,and then the tie bottom.展开更多
The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting p...The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.展开更多
A growing number of studies have demonstrated that repeated exposure to sevoflurane during development results in persistent social abnormalities and cognitive impairment.Davunetide,an active fragment of the activity-...A growing number of studies have demonstrated that repeated exposure to sevoflurane during development results in persistent social abnormalities and cognitive impairment.Davunetide,an active fragment of the activity-dependent neuroprotective protein(ADNP),has been implicated in social and cognitive protection.However,the potential of davunetide to attenuate social deficits following sevoflurane exposure and the underlying developmental mechanisms remain poorly understood.In this study,ribosome and proteome profiles were analyzed to investigate the molecular basis of sevoflurane-induced social deficits in neonatal mice.The neuropathological basis was also explored using Golgi staining,morphological analysis,western blotting,electrophysiological analysis,and behavioral analysis.Results indicated that ADNP was significantly down-regulated following developmental exposure to sevoflurane.In adulthood,anterior cingulate cortex(ACC)neurons exposed to sevoflurane exhibited a decrease in dendrite number,total dendrite length,and spine density.Furthermore,the expression levels of Homer,PSD95,synaptophysin,and vglut2 were significantly reduced in the sevoflurane group.Patch-clamp recordings indicated reductions in both the frequency and amplitude of miniature excitatory postsynaptic currents(mEPSCs).Notably,davunetide significantly ameliorated the synaptic defects,social behavior deficits,and cognitive impairments induced by sevoflurane.Mechanistic analysis revealed that loss of ADNP led to dysregulation of Ca^(2+)activity via the Wnt/β-catenin signaling,resulting in decreased expression of synaptic proteins.Suppression of Wnt signaling was restored in the davunetide-treated group.Thus,ADNP was identified as a promising therapeutic target for the prevention and treatment of neurodevelopmental toxicity caused by general anesthetics.This study provides important insights into the mechanisms underlying social and cognitive disturbances caused by sevoflurane exposure in neonatal mice and elucidates the regulatory pathways involved.展开更多
We aimed to investigate if college students’ dietary and physical activity adhered to the Chinese Dietary Guidelines, the Composing Editorial Board of Physical Activity Guidelines, and WHO recommendation for NCDs pre...We aimed to investigate if college students’ dietary and physical activity adhered to the Chinese Dietary Guidelines, the Composing Editorial Board of Physical Activity Guidelines, and WHO recommendation for NCDs prevention. Methods: A 3-day (2 weekdays and 1 weekend day) 24-hour (24-HRs) dietary recall was conducted to record details of participants’ food consumption. One-way analysis of variance (ANOVA) was applied to examine the influence of the identified demographic variables (including BMI, gender, major, family monthly income, and place of household registration) on the 8 food groups’ consumption. We analyzed the effect of the various demographic variables on sodium intake by the student’s t-test. The questionnaire, International Physical Activity Questionnaire (IPAQ)-Short Form, was utilized to assess participants’ physical activity (PA) level. The Wilcoxon-Mann-Whitney was applied to analyze participants’ physical activity. Results: Our research indicated participants consumed much fewer fruits and vegetables and excessive meats on average for both males and females regarding NCDs prevention. Conclusion: Participants’ dietary intake did not comply with the Chinese Dietary Guide-lines recommendation for chronic diseases prevention. Nutrition knowledge and health education are needed for college students. .展开更多
Emergency decision-making problems usually involve many experts with different professional backgrounds and concerns,leading to non-cooperative behaviors during the consensus-reaching process.Many studies on noncooper...Emergency decision-making problems usually involve many experts with different professional backgrounds and concerns,leading to non-cooperative behaviors during the consensus-reaching process.Many studies on noncooperative behavior management assumed that the maximumdegree of cooperation of experts is to totally accept the revisions suggested by the moderator,which restricted individuals with altruistic behaviors to make more contributions in the agreement-reaching process.In addition,when grouping a large group into subgroups by clustering methods,existing studies were based on the similarity of evaluation values or trust relationships among experts separately but did not consider them simultaneously.In this study,we introduce a clustering method considering the similarity of evaluation values and the trust relations of experts and then develop a consensusmodel taking into account the altruistic behaviors of experts.First,we cluster experts into subgroups by a constrained Kmeans clustering algorithm according to the opinion similarity and trust relationship of experts.Then,we calculate the weights of experts and clusters based on the centrality degrees of experts.Next,to enhance the quality of consensus reaching,we identify three kinds of non-cooperative behaviors and propose corresponding feedback mechanisms relying on the altruistic behaviors of experts.A numerical example is given to show the effectiveness and practicality of the proposed method in emergency decision-making.The study finds that integrating altruistic behavior analysis in group decision-making can safeguard the interests of experts and ensure the integrity of decision-making information.展开更多
基金supported by the Scientific Research Project of Hunan Provincial Department of Education(22C0642).
文摘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.
基金financially supported by JSPS KAKENHI Grant Number JP19K15083.
文摘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.
基金the National Natural Science Foundation of China through Contract/Grant Numbers 12002245,12172263 and 11772237Chongqing Jiaotong University through Contract/Grant Number F1220038.
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.52171098 and 51921001)the State Key Laboratory for Advanced Metals and Materials(No.2022Z-02)+1 种基金the National High-level Personnel of Special Support Program(No.ZYZZ2021001)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-20-03C2 and FRF-BD-20-02B).
文摘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.
基金supported by the National Natural Science Foundation of China (No. 41471062, No. 41971085, No. 41971086)。
文摘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.
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China(No.92160301)the Industrial Technology Development Program,China(No.JCKY2021605 B026)。
文摘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.
基金Project supported by the National Natural Science Foundation of China(Nos.11832002 and 12072201)。
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.51839009 and 52027814)the Natural Science Foundation of Hubei Province(No.2023AFB589).
文摘High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data.
文摘Objective:This study aimed to examine the causal model of eating behaviors among pregnant women working in industrial factories.Methods:This cross-sectional study was conducted on 210 participants,attending 4 healthcare centers,at a tertiary care hospital in Chonburi province,Thailand.Data were collected using 7 questionnaires:demographic form,eating behavior questionnaire,perceived benefits of the healthy eating questionnaire,perceived barriers to the healthy eating questionnaire,perceived self-efficacy questionnaire,social support questionnaire,and accessibility to healthy foods questionnaire.Descriptive statistics and path analysis were used for data analysis.Results:The participants had relatively high mean scores for eating behaviors.The final model fitted well with the dataχ^(2)=12.86,df=10,P=0.23;χ^(2)/df=1.29;comparative fit index(CFI)=0.98;goodness-of-fit index(GFI)=0.98;adjusted goodness-of-fit index(AGFI)=0.95;root mean square error of approximation(RMSEA)=0.04.Four factors-perceived benefits(β=0.13,P<0.05),perceived self-efficacy in healthy eating(β=0.22,P<0.001),pregnancy planning(β=0.28,P<0.001),and accessibility to healthy foods in the factory(β=0.12,P<0.05)-positively affected eating behavior,while only perceived barriers to healthy eating had a negative effect on eating behavior(β=−0.24,P<0.001).All the above factors explained 27.2%of the variance in eating behaviors.Conclusions:Nurses or healthcare providers can apply these findings to create an eating behavior modification program,focusing on pregnancy planning,behavior-specific variables,and interpersonal and situational influence,to promote the nutritional status of pregnant women working in industrial factories.
基金financial support from the National Key Research and Development Program of China (2019YFB2005401)National Natural Science Foundation of China (Nos. 91860207 and 52175420)+5 种基金Shandong Provincial Key Research and Development Program (Major Scientific and Technological Innovation Project)(No. 2020CXGC010204)Shandong Provincial Natural Science Foundation of China (2021JMRH0301 and2021JMRH0304)Taishan Scholar FoundationInternational Partnership Scheme of the Bureau of the International Scientific Cooperation of the Chinese Academy of Sciences(No. 181722KYSB20180015)Research and Innovation Office of The Hong Kong Polytechnic University (BBX5and BBX7)funding support to the State Key Laboratories in Hong Kong
文摘Material removal in the cutting process is regarded as a friction system with multiple input and output variables.The complexity of the cutting friction system is caused by the extreme conditions existing on the tool–chip and tool–workpiece interfaces.The critical issue is significant to use knowledge of cutting friction behaviors to guide researchers and industrial manufacturing engineers in designing rational cutting processes to reduce tool wear and improve surface quality.This review focuses on the state of the art of research on friction behaviors in cutting procedures as well as future perspectives.First,the cutting friction phenomena under extreme conditions,such as high temperature,large strain/strain rates,sticking–sliding contact states,and diverse cutting conditions are analyzed.Second,the theoretical models of cutting friction behaviors and the application of simulation technology are discussed.Third,the factors that affect friction behaviors are analyzed,including material matching,cutting parameters,lubrication/cooling conditions,micro/nano surface textures,and tool coatings.Then,the consequences of the cutting friction phenomena,including tool wear patterns,tool life,chip formation,and the machined surface are analyzed.Finally,the research limitations and future work for cutting friction behaviors are discussed.This review contributes to the understanding of cutting friction behaviors and the development of high-quality cutting technology.
基金supported by the National Natural Science Foundation of China(Grant No.51771054,52171236)State Key Program of National Natural Science Foundation of China(Grant No.51631003)+5 种基金National Key Research and Development Program of China(Grant No.2016YFC1102402)Open Research Fund of Jiangsu Key Laboratory for Advanced Metallic Materials(Grant No.AMM2021A01)the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(Grant No.ASMA201901)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX20_0091)Natural Science Foundation of Jiangsu Province(BK20181020)the Introduction of Talent Research Fund in Nanjing Institute of Technology(YKJ201705)
文摘Biomedical degradable materials would be subjected to different degrees and forms of static stress after being implanted in the human body.In this work,the biocorrosion behaviors of AZ31B magnesium alloy under different stress forms with different magnitudes(20~150MPa)were studied.It was found that the corrosion behaviors at stressed conditions were severer than those at unstressed conditions and corrosion rates were obviously accelerated.The biocorrosion behaviors are more sensitive to the effects of tensile loads than to compressive loads.A biocorrosion numerical model on the degradation process of Mg alloy under static loads was established.The corrosion current density(i_(corr))of Mg alloy and the applied static stress(σ)matches a linear relationship of ln i_(corr)~σwell during the early stage(within 24 hrs)while deviated gradually in the latter period of corrosion.This work could provide a guidance and theoretical reference for further researches on the biocorrosion behaviors and practical clinical applications of the biomedical materials subjected to physiological loads.
基金financially supported by the National Key R&D Program of China (No. 2018YFB0104400)the National Natural Science Foundation of China (Nos. 52074036, 51725401, and 51874019)Beijing Municipal Science and Technology Commission (No. Z191100002719007)
文摘Pyrolytic graphite (PG) with highly aligned graphene layers,present anisotropic electrical and thermal transport behavior,which is attractive in electronic,electrocatalyst and energy storage.Such pristine PG could meeting the limit of electrical conductivity (~2.5×10^(4) S·cm^(−1)),although efforts have been made for achieving high-purity sp^(2) hybridized carbon.For manipulating the electrical conductivity of PG,a facile and efficient electrochemical strategy is demonstrated to enhance electrical transport ability via reversible intercalation/de-intercalation of AlCl_(4)^(-)into the graphitic interlayers.With the stage evolution at different voltages,variable electrical and thermal transport behaviors could be achieved via controlling AlCl_(4)^(-)concentrations in the PG because of substantial variation in the electronic density of states.Such evolution leads to decoupled electrical and thermal transport (opposite variation trend) in the in-plane and out-of-plane directions,and the in-plane electrical conductivity of the pristine PG (1.25×10^(4) S·cm^(−1)) could be massively promoted to 4.09×10^(4) S·cm(AlCl_(4)^(-)intercalated PG),much better than the pristine bulk graphitic papers used for the electrical transport and electromagnetic shielding.The fundamental mechanism of decoupled transport feature and electrochemical strategy here could be extended into other anisotropic conductive bulks for achieving unusual behaviors.
基金This work has been supported by the National Key Research and Development Program(Grant No.2017YFC0603000)which was jointly completed by the Coal Mining Research Branch of CCRI,China University of Mining and Technology(Xuzhou and Beijing),Henan Polytechnic UniversityXinji Energy Company Limited of China Coal Energy Group.This work was also supported by the National Natural Science Foundation of China(Grant No.51927807)。
文摘This paper reviews the major achievements in terms of mechanical behaviors of coal measures,mining stress distribution characteristics and ground control in China’s deep underground coal mining.The three main aspects of this review are coal measure mechanics,mining disturbance mechanics,and rock support mechanics.Previous studies related to these three topics are reviewed,including the geo-mechanical properties of coal measures,distribution and evolution characteristics of mining-induced stresses,evolution characteristics of mining-induced structures,and principles and technologies of ground control in both deep roadways and longwall faces.A discussion is made to explain the structural and mechanical properties of coal measures in China’s deep coal mining practices,the types and dis-tribution characteristics of in situ stresses in underground coal mines,and the distribution of mining-induced stress that forms under different geological and engineering conditions.The theory of pre-tensioned rock bolting has been proved to be suitable for ground control of deep underground coal roadways.The use of combined ground control technology(e.g.ground support,rock mass modification,and destressing)has been demonstrated to be an effective measure for rock control of deep roadways.The developed hydraulic shields for 1000 m deep ultra-long working face can effectively improve the stability of surrounding rocks and mining efficiency in the longwall face.The ground control challenges in deep underground coal mines in China are discussed,and further research is recommended in terms of theory and technology for ground control in deep roadways and longwall faces.
基金the financial support provided by the National Natural Science Foundation of China(Grant No.42302332)the Special Funding of Chongqing Postdoctoral Research Project(Grant No.2022CQBSHTB2061,2022CQBSHTB1010)+3 种基金the Chongqing Postdoctoral Science Foundation(Grant No.CSTB2022NSCQ-BHX0738,CSTB2023NSCQBHX0223)the China Postdoctoral Science Foundation(Grant No.2023M730432)the Natural Science Foundation of Chongqing(Grant No.CSTB2023NSCQMSX0913,cstc2021jcyj-msxm X0869)the Postdoctoral Science Foundation of Chongqing Jiaotong University(Grant No.F1220105,22JDKJC-A008)。
文摘Tunnel-type anchorages(TTAs)installed in human gathering areas are characterized by a shallow burial depth,and in many instances,they utilize soft rock as the bearing stratum.However,the stability control measures and the principle of shallow TTAs in soft rock have not been fully studied.Hence,a structure suitable for improving the stability of shallow TTAs in soft rock strata,named the anti-pull tie(APT),was added to the floor of the back face.Physical tests and numerical models were established to study the influence of the APT on the load transfer of TTAs,the mechanical response of the surrounding rock,the stress distribution of the interface,and the failure model.The mechanical characteristics of APTs were also studied.The results show that the ultimate bearing capacity of TTAs with an APT is increased by approximately 11.8%,as compared to the TTAs without an APT.Also,the bearing capacity of TTAs increases approximately linearly with increasing height,width,length,and quantity of APTs,and decreases approximately linearly with increasing distance from the back face and slope angle of the tie slope.The normal squeezing between the tie slope and the surrounding rock increases the shear resistance of the interface and expands the range of the surrounding rock participating in bearing sharing.Both tension and compression zones exist in the APT during loading.The tension zone extends from the tie toe to the tie bottom along the tie slope.The range of the tie body tension zone constantly expands to the deep part of the APT with an increasing load.The peak tensile stress value is located at the tie toe.The distribution of compressive stress in the tie body is the largest at the tie top,followed by the tie slope,and then the tie bottom.
基金supported by the National Natural Science Foundation of China(Nos.52174277 and 51874077)the Fundamental Funds for the Central Universities,China(No.N2225032)+1 种基金the China Postdoctoral Science Foundation(No.2022M720683)the Postdoctoral Fund of Northeastern University,China。
文摘The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.
基金supported by the National Natural Science Foundation of China(82171170,81971076,82371277 to H.Z.,82101345 to L.R.L.)。
文摘A growing number of studies have demonstrated that repeated exposure to sevoflurane during development results in persistent social abnormalities and cognitive impairment.Davunetide,an active fragment of the activity-dependent neuroprotective protein(ADNP),has been implicated in social and cognitive protection.However,the potential of davunetide to attenuate social deficits following sevoflurane exposure and the underlying developmental mechanisms remain poorly understood.In this study,ribosome and proteome profiles were analyzed to investigate the molecular basis of sevoflurane-induced social deficits in neonatal mice.The neuropathological basis was also explored using Golgi staining,morphological analysis,western blotting,electrophysiological analysis,and behavioral analysis.Results indicated that ADNP was significantly down-regulated following developmental exposure to sevoflurane.In adulthood,anterior cingulate cortex(ACC)neurons exposed to sevoflurane exhibited a decrease in dendrite number,total dendrite length,and spine density.Furthermore,the expression levels of Homer,PSD95,synaptophysin,and vglut2 were significantly reduced in the sevoflurane group.Patch-clamp recordings indicated reductions in both the frequency and amplitude of miniature excitatory postsynaptic currents(mEPSCs).Notably,davunetide significantly ameliorated the synaptic defects,social behavior deficits,and cognitive impairments induced by sevoflurane.Mechanistic analysis revealed that loss of ADNP led to dysregulation of Ca^(2+)activity via the Wnt/β-catenin signaling,resulting in decreased expression of synaptic proteins.Suppression of Wnt signaling was restored in the davunetide-treated group.Thus,ADNP was identified as a promising therapeutic target for the prevention and treatment of neurodevelopmental toxicity caused by general anesthetics.This study provides important insights into the mechanisms underlying social and cognitive disturbances caused by sevoflurane exposure in neonatal mice and elucidates the regulatory pathways involved.
文摘We aimed to investigate if college students’ dietary and physical activity adhered to the Chinese Dietary Guidelines, the Composing Editorial Board of Physical Activity Guidelines, and WHO recommendation for NCDs prevention. Methods: A 3-day (2 weekdays and 1 weekend day) 24-hour (24-HRs) dietary recall was conducted to record details of participants’ food consumption. One-way analysis of variance (ANOVA) was applied to examine the influence of the identified demographic variables (including BMI, gender, major, family monthly income, and place of household registration) on the 8 food groups’ consumption. We analyzed the effect of the various demographic variables on sodium intake by the student’s t-test. The questionnaire, International Physical Activity Questionnaire (IPAQ)-Short Form, was utilized to assess participants’ physical activity (PA) level. The Wilcoxon-Mann-Whitney was applied to analyze participants’ physical activity. Results: Our research indicated participants consumed much fewer fruits and vegetables and excessive meats on average for both males and females regarding NCDs prevention. Conclusion: Participants’ dietary intake did not comply with the Chinese Dietary Guide-lines recommendation for chronic diseases prevention. Nutrition knowledge and health education are needed for college students. .
基金supported by the National Natural Science Foundation of China (Nos.71771156,71971145,72171158).
文摘Emergency decision-making problems usually involve many experts with different professional backgrounds and concerns,leading to non-cooperative behaviors during the consensus-reaching process.Many studies on noncooperative behavior management assumed that the maximumdegree of cooperation of experts is to totally accept the revisions suggested by the moderator,which restricted individuals with altruistic behaviors to make more contributions in the agreement-reaching process.In addition,when grouping a large group into subgroups by clustering methods,existing studies were based on the similarity of evaluation values or trust relationships among experts separately but did not consider them simultaneously.In this study,we introduce a clustering method considering the similarity of evaluation values and the trust relations of experts and then develop a consensusmodel taking into account the altruistic behaviors of experts.First,we cluster experts into subgroups by a constrained Kmeans clustering algorithm according to the opinion similarity and trust relationship of experts.Then,we calculate the weights of experts and clusters based on the centrality degrees of experts.Next,to enhance the quality of consensus reaching,we identify three kinds of non-cooperative behaviors and propose corresponding feedback mechanisms relying on the altruistic behaviors of experts.A numerical example is given to show the effectiveness and practicality of the proposed method in emergency decision-making.The study finds that integrating altruistic behavior analysis in group decision-making can safeguard the interests of experts and ensure the integrity of decision-making information.