Cubic-shaped magnetic particles subjected to a dimensionless uniaxial anisotropy(Q=0.1)aligned with one of the crystallographic axes provide an ideal system for investigating magnetic equilibrium states.In this system...Cubic-shaped magnetic particles subjected to a dimensionless uniaxial anisotropy(Q=0.1)aligned with one of the crystallographic axes provide an ideal system for investigating magnetic equilibrium states.In this system,three fundamental magnetization configurations are identified:(i)the flower state,(ii)the twisted flower state,and(iii)the vortex state.This problem corresponds to standard problem No.3 proposed by the NIST Micromagnetics Modeling Group,widely adopted as a benchmark for validating computational micromagnetics methods.In this work,we approach the problem using a computational method based on direct dipolar interactions,in contrast to conventional techniques that typically compute the demagnetizing field via finite difference-based fast Fourier transform(FFT)methods,tensor grid approaches,or finite element formulations.Our results are compared with established literature data,focusing on the dimensionless parameterλ=L/l_(ex),where L is the cube edge length and l_(ex)is the exchange length of the material.To analyze equilibrium state transitions,we systematically varied the size L as a function of the simulation cell number N and intercellular spacing a,determining the criticalλvalue associated with configuration changes.Our simulations reveal that the transition between the twisted flower and vortex states occurs atλ≈8.45,consistent with values reported in the literature,validating our code(Grupo de Física da Matéeria Condensada-UFJF),and shows that this standard problem can be resolved using only interaction dipolar of a direct way without the need for sophisticated additional calculations.展开更多
UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechani...UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.展开更多
Extreme traffic loads significantly challenge the safety and cost-effectiveness of highway bridges,especially under site-specific traffic conditions.Conventional assessments often rely on overly conservative load mode...Extreme traffic loads significantly challenge the safety and cost-effectiveness of highway bridges,especially under site-specific traffic conditions.Conventional assessments often rely on overly conservative load models,leading to excessive structural design.In this study,a framework for the prediction of maximum bending moments in simply supported bridges is developed by integrating weigh-in-motion(WIM)data,traffic microsimulation,and generalized extreme value(GEV)regression modeling to establish relationships between the GEV parameters(μ,σ,ξ)and traffic factors—heavy vehicle proportion,bridge span length,vehicle speed,headway,and traffic volume.Using one-year WIM data from 7.4 million vehicles,the developed models for μ and σ exhibit high predictive accuracy(R^(2)>0.95)and are validated through leave-one-out cross-validation.The prediction of ξ is less accurate(R^(2)≈0.6),requiring further improvement.Applying these models to a 1000-year return level yields a reliable,data-driven extrapolation,supporting optimized bridge design and safety assessment under varying traffic conditions.展开更多
This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theo...This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theorem,fixed point index theory and the analytic technique,we give the bifurcation point of the parameter which divides the range of parameter for the existence of at least two,one and no positive solutions for the problem.And,by using a fixed point theorem of generalized concave operator and cone theory,we establish the maximum parameter interval for the existence of the unique positive solution for the problem and show that such a positive solution continuously depends on the parameter.In the end,some examples are given to illustrate our main results.展开更多
Numerous economically underdeveloped and ecologically fragile areas in southern China's mountainous regions face increasing challenges in achieving sustainable development. A comparative analysis of ecosystem serv...Numerous economically underdeveloped and ecologically fragile areas in southern China's mountainous regions face increasing challenges in achieving sustainable development. A comparative analysis of ecosystem service responses to land use scenarios, incorporating adaptive valuation coefficients, can reveal actionable pathways to reconcile sustainable development and ecological conservation in mountainous regions. In this study, the ecosystem service value(ESV) dynamics in the Hunan–Jiangxi Border Region(HJBR), which is a representative old revolutionary base with a relatively undeveloped economy, were investigated by integrating historical land use data analysis from 2000 to 2020 and adopting patch-generating land use simulation(PLUS) modelling. Three policy-responsive scenarios, namely, natural growth(NGS), farmland protection(FPS), and ecological protection(EPS), were systematically developed to project ESV variations for 2030 and 2040. Our analysis revealed that from 2000 to 2020, urban sprawl and water body expansion occurred at the expense of forestland, cultivated land, and grassland, yet yield-driven productivity improvements increased the ESV by 227.30%(equivalent to ¥250.0 billion). By 2040, the NGS achieves the greatest ESV increase(¥189.895 billion) while fully accommodating urban land demand;the FPS yields the smallest ESV increase(¥148.169 billion), with the EPS occupying an intermediate position(¥182.207 billion). Climate regulation and hydrological services dominate ecological functions, collectively exceeding 49% across all the scenarios and periods. By 2040, most service functions exhibit growth trends except for a 0.30% water supply decline under the FPS, whereas the EPS demonstrates balanced development through multidimensional service enhancements. These findings underscore the necessity of integrating ecological safeguards into land use planning frameworks to ensure sustainable regional development.展开更多
Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under diff...Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under different deposition rates and grain orientations.The evolution of grain morphology and grain orientation was also taken into consideration.Simulation results show that at lower deposition rates,the surface of the formed Ti film exhibits a distinct oriented texture structure.The surface roughness of the Ti film is positively correlated with the grain misorientation.Moreover,the surface roughness obtained from the simulation is in good agreement with the experiment results.展开更多
The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations,where various core-shell structures were obtained by precise control of the initial and boundary conditions of the...The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations,where various core-shell structures were obtained by precise control of the initial and boundary conditions of the TiNb binary alloy system during spinodal decomposition,and then the formation mechanism of core-shell structure was revealed.In addition,the influences of initial temperature gradient,average temperature,and initial concentration distribution of the system on the core-shell structure were investigated.Results show that the initial concentration gradient is the key factor for forming the core-shell structure.Besides,larger initial temperature gradient and higher average temperature can promote the formation of core-shell structure,which can be stabilized by adjusting the initial concentration distribution of the Nb-rich region in TiNb binary alloy.As a theoretical basis,this research provides a novel and simple strategy for the preparation of TiNb-based alloys and other materials with peculiar core-shell structures and desirable mechanical and physical properties.展开更多
Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing addit...Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.展开更多
Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verifica...Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verification of quantum contextuality has been predominantly investigated in the single-photon regime and analyzed under approximation condition of infinitesimally small perturbation strength.This study releases the approximation condition and takes into account the impact of perturbation strength on the rigor of the verification.And the investigation on the verification of contextuality is extended to the multi-photon scenarios for observing the influence of the correlation between photons on the verification.Without the limitation of infinitesimally small probability of disturbance,anomalous weak values are identified as necessary for contextuality to emerge,thereby refining the criterion proposed by Pusey[Phys.Rev.Lett.113200401(2014)].In the multi-photon scenarios,the emergence of contextuality also depends strongly on both the photon number and the photon-number distribution state.In particular,contextuality is found to be maximized when the single-photon component dominates and the second-order correlation is lower.These results highlight the critical role of photon statistics in experimental tests of contextuality via anomalous weak values.展开更多
BACKGROUND:Although the Confusion Assessment Methods for the Intensive Care Unit(CAMICU) is a recommended tool for diagnosing sepsis-associated encephalopathy(SAE),it has several limitations.Mismatch-negativity(MMN) a...BACKGROUND:Although the Confusion Assessment Methods for the Intensive Care Unit(CAMICU) is a recommended tool for diagnosing sepsis-associated encephalopathy(SAE),it has several limitations.Mismatch-negativity(MMN) and P3a are components of event-related potentials(ERPs) used with electroencephalography(EEG) and are associated with cerebral function changes in critically ill patients.This study aimed to provide a quantitative,non-invasive method to guide SAE diagnosis in nonsedated patients.METHODS:From January 2022 to March 2023,sepsis patients without sedation were enrolled and assessed via the CAM-ICU,Glasgow Coma Scale(GCS),and ERP under standard procedures.Both MMN and P3a data were collected.The diagnostic value of MMN and P3a was assessed with processed ERP data.RESULTS:Thirty-six patients were included in this study,comprising 19 patients with SAE and 17 patients without SAE(NSAE).MMN and P3a amplitudes decreased,and only FzMMN amplitude significantly decreased in SAE patients(2.03 [1.08,2.93] mV vs.3.21 [1.92,4.34] mV,P=0.040).After median dichotomization,low F3P3a and FzP3a amplitudes were associated with higher CAM-ICU positivity rates and APACHE II scores.Both amplitude in F3P3a(AUC=0.710,95%CI:0.527–0.893,P=0.034) and FzP3a(AUC=0.700,95%CI:0.519–0.881,P=0.041) exhibited moderate diagnostic efficacy for SAE,while FzMMN amplitude lacks effective diagnostic value.CONCLUSION:In this pilot study,ERP components F3P3a and FzP3a amplitudes demonstrated moderate diagnostic value for SAE.These exploratory findings require confirmation in larger and powered cohorts.展开更多
Polyethersulfone(PES)can be widely used in extreme environments due to its exceptional strength and stability.In this study,molecular dynamics(MD)simulations were used to construct tribological models of PES under var...Polyethersulfone(PES)can be widely used in extreme environments due to its exceptional strength and stability.In this study,molecular dynamics(MD)simulations were used to construct tribological models of PES under varying pressures.The variations of PES molecular chains and frictional interface properties were explored for understanding microscopic tribological mechanism.The simulation results show that high pressure and high vacuum conditions reduce the coefficient of friction and wear rate.The variations in radial distribution function(RDF),relative concentration of atoms,friction interface temperature,and atomic motion velocity were analyzed.It was found that high pressure and high vacuum promote PES molecular chains moving away from the surface of the iron atomic layer,decreasing interaction energy,RDF,temperature,and velocity at the friction interface.This work offers novel methodologies and theoretical insights for studying the friction and wear of polymer composites in complex environments.展开更多
The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segmen...The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segment forming the ATP catalytic pocket is highly conserved.Single-molecule experiments,however,have revealed subtle differences in efficiency between the F_(1) and V_(1) motors.Here,we perform both atomistic and coarse-grained molecular dynamics simulations to investigate the mechanochemical coupling and coordination in F_(1) and V_(1) ATPase.Our results show that the correlation between conformational changes in F_(1) is stronger than that in V_(1),indicating that the mechanochemical coupling in F_(1) is tighter than in V_(1).Moreover,the unidirectional rotation of F_(1) is more processive than that of V_(1),which accounts for the higher efficiency observed in F_(1) and explains the occasional backward steps detected in single-molecule experiments on V_(1).展开更多
Solar-driven H_(2) production coupled with selective organic transformation represents a promising strategy for co-generation of green hydrogen and high-value chemicals,yet its feasibility relies critically on effecti...Solar-driven H_(2) production coupled with selective organic transformation represents a promising strategy for co-generation of green hydrogen and high-value chemicals,yet its feasibility relies critically on effective bifunctional photocatalysts.Herein,we report the synthesis of ultrafine Cd_(x)Zn_(1-x)S nanocrystals derived from a zeolitic imidazolate framework(ZIF),featuring high surface area,shortened charge diffusion path,and enhanced H_(2) evolution activity.Anchoring amorphous Pt sub-nanoclusters onto these nanocrystals created a bifunctional catalyst(Pt-Cd_(x)Zn_(1-x)S)for efficient lactic acid photoreforming,enabling coproduction of H_(2) with switchable selectivity toward pyruvic acid(PA)or 2,3-dihydroxy-2,3-dimethylsuccinic acid(DTA).The optimized 0.5Pt-Cd_(0.3)Zn_(0.7)S catalyst achieved an exceptional H_(2) production rate of 270.6 mmol h^(-1) g^(-1),73.1%PA selectivity,and 62.8% apparent quantum efficiency at 400 nm.Mechanistic studies revealed that lactic acid undergoes C-H cleavage to form carbon-centered radicals.Pt sub-nanoclusters served as electron sinks to facilitate O-H dissociation and PA formation,whereas pristine Cd_(0.3)Zn_(0.6)7S promoted direct C-C coupling of radicals to predominantly yield DTA.This work offers critical insights for designing advanced bifunctional photocatalysts to integrate solar hydrogen and value-added chemical synthesis.展开更多
基金CAPES,CNPq,and FAPEMIG(Brazilian Agencies)for their financial support。
文摘Cubic-shaped magnetic particles subjected to a dimensionless uniaxial anisotropy(Q=0.1)aligned with one of the crystallographic axes provide an ideal system for investigating magnetic equilibrium states.In this system,three fundamental magnetization configurations are identified:(i)the flower state,(ii)the twisted flower state,and(iii)the vortex state.This problem corresponds to standard problem No.3 proposed by the NIST Micromagnetics Modeling Group,widely adopted as a benchmark for validating computational micromagnetics methods.In this work,we approach the problem using a computational method based on direct dipolar interactions,in contrast to conventional techniques that typically compute the demagnetizing field via finite difference-based fast Fourier transform(FFT)methods,tensor grid approaches,or finite element formulations.Our results are compared with established literature data,focusing on the dimensionless parameterλ=L/l_(ex),where L is the cube edge length and l_(ex)is the exchange length of the material.To analyze equilibrium state transitions,we systematically varied the size L as a function of the simulation cell number N and intercellular spacing a,determining the criticalλvalue associated with configuration changes.Our simulations reveal that the transition between the twisted flower and vortex states occurs atλ≈8.45,consistent with values reported in the literature,validating our code(Grupo de Física da Matéeria Condensada-UFJF),and shows that this standard problem can be resolved using only interaction dipolar of a direct way without the need for sophisticated additional calculations.
基金financially supported by the National Natural Science Foundation of China(Nos.52303298 and 52233002)。
文摘UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.
基金The National Natural Science Foundation of China(No.52278149)the Natural Science Foundation of Jiangsu Province(No.BZ2024015)+1 种基金the Opening Project of State Key Laboratory for Track Technology of High-Speed Railway(No.2023YJ375)the Opening Project of Zhejiang Engineering Centre of Road and Bridge Intelligent Operation and Maintenance Technology(No.202402G).
文摘Extreme traffic loads significantly challenge the safety and cost-effectiveness of highway bridges,especially under site-specific traffic conditions.Conventional assessments often rely on overly conservative load models,leading to excessive structural design.In this study,a framework for the prediction of maximum bending moments in simply supported bridges is developed by integrating weigh-in-motion(WIM)data,traffic microsimulation,and generalized extreme value(GEV)regression modeling to establish relationships between the GEV parameters(μ,σ,ξ)and traffic factors—heavy vehicle proportion,bridge span length,vehicle speed,headway,and traffic volume.Using one-year WIM data from 7.4 million vehicles,the developed models for μ and σ exhibit high predictive accuracy(R^(2)>0.95)and are validated through leave-one-out cross-validation.The prediction of ξ is less accurate(R^(2)≈0.6),requiring further improvement.Applying these models to a 1000-year return level yields a reliable,data-driven extrapolation,supporting optimized bridge design and safety assessment under varying traffic conditions.
基金Supported by the National Natural Science Foundation of China(11361047)Fundamental Research Program of Shanxi Province(20210302124529)。
文摘This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theorem,fixed point index theory and the analytic technique,we give the bifurcation point of the parameter which divides the range of parameter for the existence of at least two,one and no positive solutions for the problem.And,by using a fixed point theorem of generalized concave operator and cone theory,we establish the maximum parameter interval for the existence of the unique positive solution for the problem and show that such a positive solution continuously depends on the parameter.In the end,some examples are given to illustrate our main results.
基金supported by the National Natural Science Foundation of China(No.4230130142401322)+2 种基金the Scientific Research Foundation of Hunan Provincial Education Department,China(No.22A0159No.22B0191)the Fund Project of Key Laboratory of Rule of Law Research of Ministry of Natural Resources(CUGFZ-2204)。
文摘Numerous economically underdeveloped and ecologically fragile areas in southern China's mountainous regions face increasing challenges in achieving sustainable development. A comparative analysis of ecosystem service responses to land use scenarios, incorporating adaptive valuation coefficients, can reveal actionable pathways to reconcile sustainable development and ecological conservation in mountainous regions. In this study, the ecosystem service value(ESV) dynamics in the Hunan–Jiangxi Border Region(HJBR), which is a representative old revolutionary base with a relatively undeveloped economy, were investigated by integrating historical land use data analysis from 2000 to 2020 and adopting patch-generating land use simulation(PLUS) modelling. Three policy-responsive scenarios, namely, natural growth(NGS), farmland protection(FPS), and ecological protection(EPS), were systematically developed to project ESV variations for 2030 and 2040. Our analysis revealed that from 2000 to 2020, urban sprawl and water body expansion occurred at the expense of forestland, cultivated land, and grassland, yet yield-driven productivity improvements increased the ESV by 227.30%(equivalent to ¥250.0 billion). By 2040, the NGS achieves the greatest ESV increase(¥189.895 billion) while fully accommodating urban land demand;the FPS yields the smallest ESV increase(¥148.169 billion), with the EPS occupying an intermediate position(¥182.207 billion). Climate regulation and hydrological services dominate ecological functions, collectively exceeding 49% across all the scenarios and periods. By 2040, most service functions exhibit growth trends except for a 0.30% water supply decline under the FPS, whereas the EPS demonstrates balanced development through multidimensional service enhancements. These findings underscore the necessity of integrating ecological safeguards into land use planning frameworks to ensure sustainable regional development.
基金National MCF Energy R&D Program of China(2018YFE0306100)Natural Science Foundation of Hunan Province for Distinguished Young Scholars(2021JJ10062)+1 种基金National Natural Science Foundation of China(52101028)China Postdoctoral Science Foundation(2021M703628)。
文摘Combining the phase-field method and the moving boundary method,a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under different deposition rates and grain orientations.The evolution of grain morphology and grain orientation was also taken into consideration.Simulation results show that at lower deposition rates,the surface of the formed Ti film exhibits a distinct oriented texture structure.The surface roughness of the Ti film is positively correlated with the grain misorientation.Moreover,the surface roughness obtained from the simulation is in good agreement with the experiment results.
基金National Natural Science Foundation of China(12372152)Guangdong Basic and Applied Basic Research Foundation(2023A1515011819,2024A1515012469)Shandong Provincial Natural Science Foundation(ZR2023MA058)。
文摘The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations,where various core-shell structures were obtained by precise control of the initial and boundary conditions of the TiNb binary alloy system during spinodal decomposition,and then the formation mechanism of core-shell structure was revealed.In addition,the influences of initial temperature gradient,average temperature,and initial concentration distribution of the system on the core-shell structure were investigated.Results show that the initial concentration gradient is the key factor for forming the core-shell structure.Besides,larger initial temperature gradient and higher average temperature can promote the formation of core-shell structure,which can be stabilized by adjusting the initial concentration distribution of the Nb-rich region in TiNb binary alloy.As a theoretical basis,this research provides a novel and simple strategy for the preparation of TiNb-based alloys and other materials with peculiar core-shell structures and desirable mechanical and physical properties.
基金National Key Research and Development Program of China(2022YFB4600902)Shandong Provincial Science Foundation for Outstanding Young Scholars(ZR2024YQ020)。
文摘Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.
基金Project supported by the National Natural Science Foun-dation of China(Grant Nos.62371199 and 62071186)the Natural Science Foundation of Guangdong Province,China(Grant No.2024A1515012427)+1 种基金the Quantum Science Strate-gic Initiative Project of Guangdong Province,China(Grant No.GDZX2305001)the Key Laboratory Project of Guangdong Province,China(Grant No.2020B1212060066).
文摘Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verification of quantum contextuality has been predominantly investigated in the single-photon regime and analyzed under approximation condition of infinitesimally small perturbation strength.This study releases the approximation condition and takes into account the impact of perturbation strength on the rigor of the verification.And the investigation on the verification of contextuality is extended to the multi-photon scenarios for observing the influence of the correlation between photons on the verification.Without the limitation of infinitesimally small probability of disturbance,anomalous weak values are identified as necessary for contextuality to emerge,thereby refining the criterion proposed by Pusey[Phys.Rev.Lett.113200401(2014)].In the multi-photon scenarios,the emergence of contextuality also depends strongly on both the photon number and the photon-number distribution state.In particular,contextuality is found to be maximized when the single-photon component dominates and the second-order correlation is lower.These results highlight the critical role of photon statistics in experimental tests of contextuality via anomalous weak values.
基金supported by the CAMS Innovation Fund for Medical Sciences (CIFMS)(No.2021-1-I2M-020)National High Level Hospital Clinical Research Funding (No.2022-PUMCH-B-109)National Natural Science Foundation of China (82402543)。
文摘BACKGROUND:Although the Confusion Assessment Methods for the Intensive Care Unit(CAMICU) is a recommended tool for diagnosing sepsis-associated encephalopathy(SAE),it has several limitations.Mismatch-negativity(MMN) and P3a are components of event-related potentials(ERPs) used with electroencephalography(EEG) and are associated with cerebral function changes in critically ill patients.This study aimed to provide a quantitative,non-invasive method to guide SAE diagnosis in nonsedated patients.METHODS:From January 2022 to March 2023,sepsis patients without sedation were enrolled and assessed via the CAM-ICU,Glasgow Coma Scale(GCS),and ERP under standard procedures.Both MMN and P3a data were collected.The diagnostic value of MMN and P3a was assessed with processed ERP data.RESULTS:Thirty-six patients were included in this study,comprising 19 patients with SAE and 17 patients without SAE(NSAE).MMN and P3a amplitudes decreased,and only FzMMN amplitude significantly decreased in SAE patients(2.03 [1.08,2.93] mV vs.3.21 [1.92,4.34] mV,P=0.040).After median dichotomization,low F3P3a and FzP3a amplitudes were associated with higher CAM-ICU positivity rates and APACHE II scores.Both amplitude in F3P3a(AUC=0.710,95%CI:0.527–0.893,P=0.034) and FzP3a(AUC=0.700,95%CI:0.519–0.881,P=0.041) exhibited moderate diagnostic efficacy for SAE,while FzMMN amplitude lacks effective diagnostic value.CONCLUSION:In this pilot study,ERP components F3P3a and FzP3a amplitudes demonstrated moderate diagnostic value for SAE.These exploratory findings require confirmation in larger and powered cohorts.
基金supported by the National Natural Science Foundation of China(Grant No.52275460)the Key Research and Development Program Academician Cooperation Project of Tianjin(Grant No.24YFYSHZ00270)the Tianjin University of Technology Graduate Research(Grant No.YJ2303).
文摘Polyethersulfone(PES)can be widely used in extreme environments due to its exceptional strength and stability.In this study,molecular dynamics(MD)simulations were used to construct tribological models of PES under varying pressures.The variations of PES molecular chains and frictional interface properties were explored for understanding microscopic tribological mechanism.The simulation results show that high pressure and high vacuum conditions reduce the coefficient of friction and wear rate.The variations in radial distribution function(RDF),relative concentration of atoms,friction interface temperature,and atomic motion velocity were analyzed.It was found that high pressure and high vacuum promote PES molecular chains moving away from the surface of the iron atomic layer,decreasing interaction energy,RDF,temperature,and velocity at the friction interface.This work offers novel methodologies and theoretical insights for studying the friction and wear of polymer composites in complex environments.
基金supported by the National Natural Science Foundation of China(Grant Nos.22193032 and 32401033)the Research Fund of Wenzhou Institute,Chinese Academy of Sciences(Grant Nos.WIUCASQD2020009,WIUCASQD2023005,XSZD2024004,2021HZSY0061,and WIUCASICTP2022)。
文摘The F_(1)-ATPase and V_(1)-ATPase are rotary biomotors.Alignment of their amino acid sequences,which originate from bovine heart mitochondria(1BMF)and Enterococcus hirae(3VR6),respectively,demonstrates that the segment forming the ATP catalytic pocket is highly conserved.Single-molecule experiments,however,have revealed subtle differences in efficiency between the F_(1) and V_(1) motors.Here,we perform both atomistic and coarse-grained molecular dynamics simulations to investigate the mechanochemical coupling and coordination in F_(1) and V_(1) ATPase.Our results show that the correlation between conformational changes in F_(1) is stronger than that in V_(1),indicating that the mechanochemical coupling in F_(1) is tighter than in V_(1).Moreover,the unidirectional rotation of F_(1) is more processive than that of V_(1),which accounts for the higher efficiency observed in F_(1) and explains the occasional backward steps detected in single-molecule experiments on V_(1).
基金supported by the National Natural Science Foundation of China(Grant 52276212)the National Key Research and Development Program of China(Grant 2022YFB3803600)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant BK20231211)the China Fundamental Research Funds for the Central Universities.
文摘Solar-driven H_(2) production coupled with selective organic transformation represents a promising strategy for co-generation of green hydrogen and high-value chemicals,yet its feasibility relies critically on effective bifunctional photocatalysts.Herein,we report the synthesis of ultrafine Cd_(x)Zn_(1-x)S nanocrystals derived from a zeolitic imidazolate framework(ZIF),featuring high surface area,shortened charge diffusion path,and enhanced H_(2) evolution activity.Anchoring amorphous Pt sub-nanoclusters onto these nanocrystals created a bifunctional catalyst(Pt-Cd_(x)Zn_(1-x)S)for efficient lactic acid photoreforming,enabling coproduction of H_(2) with switchable selectivity toward pyruvic acid(PA)or 2,3-dihydroxy-2,3-dimethylsuccinic acid(DTA).The optimized 0.5Pt-Cd_(0.3)Zn_(0.7)S catalyst achieved an exceptional H_(2) production rate of 270.6 mmol h^(-1) g^(-1),73.1%PA selectivity,and 62.8% apparent quantum efficiency at 400 nm.Mechanistic studies revealed that lactic acid undergoes C-H cleavage to form carbon-centered radicals.Pt sub-nanoclusters served as electron sinks to facilitate O-H dissociation and PA formation,whereas pristine Cd_(0.3)Zn_(0.6)7S promoted direct C-C coupling of radicals to predominantly yield DTA.This work offers critical insights for designing advanced bifunctional photocatalysts to integrate solar hydrogen and value-added chemical synthesis.
