WANG Jiarui runs a small building material store in Yiwu, east China＇s Zhejiang Province. When he started his business 10 years ago, getting financing was a major headache. ＂I had to begin my enterprise by borrowing...WANG Jiarui runs a small building material store in Yiwu, east China＇s Zhejiang Province. When he started his business 10 years ago, getting financing was a major headache. ＂I had to begin my enterprise by borrowing money from all my friends and relatives,＂ said the entrepreneur. In the years since then, the situation has improved Rradually.展开更多
Foreign-funded overseas industrial parks(OIPs)are crucial for attracting foreign investment and promoting globalization in developing countries.However,large-scale land acquisition for these parks generates conflicts ...Foreign-funded overseas industrial parks(OIPs)are crucial for attracting foreign investment and promoting globalization in developing countries.However,large-scale land acquisition for these parks generates conflicts between developers and local stakeholders,increasing development costs.A qualitative multicase study was conducted in this study to analyze the land transaction trajectories of China's OIPs.Four OIPs were selected to reveal the underlying mechanisms from the perspectives of institutional arrangements,governance mechanisms,and enterprise heterogeneity.The findings indicate that in host countries with insufficient institutional development,local governments are more inclined to directly engage in OIP land acquisition.High-level intergovernmental mechanisms facilitate land acquisition processes,although their efficacy depends largely on administrative power allocation across parks in host countries.The results also indicate that enterprise characteristics significantly influence land acquisition,where microscale private enterprises lacking political connections often employ low-cost,bottom-up strategies by leveraging international experience.In summary,policy-makers in developing countries should prioritize enhancing OIP governance to mitigate transaction costs,promote diversified land supply,and optimize land allocation.By depicting China's OIP land acquisition processes,this study deepens the academic understanding of OIP governance in developing countries and related international land transactions,offering practical OIP management insights for governments in both host and parent countries.展开更多
Thick and highly conductive poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate films with ideal porous structure are fulfilling as electrodes for supercapacitors.However,the homogeneous micro-structure without the...Thick and highly conductive poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate films with ideal porous structure are fulfilling as electrodes for supercapacitors.However,the homogeneous micro-structure without the aid of templates or composite presents a significant obstacle,due to the intrinsic softness of the dominant PSS component.In this study,we have successfully developed a porous configuration by employing a solvothermal approach with ethylene glycol(EG)as the solvent.The synergistic action of elevated pressure and temperature was crucial in prompting EG to tailor the microstructure of the PEDOT:PSS films by removing non-conductive PSS chains and improving PEDOT crystallinity,and the formation of a porous network.The resulting porous PEDOT:PSS films exhibited a high conductivity of 1644 S cm^(-1)and achieved a volumetric capacitance record of 270 F cm^(-3),markedly exceeding previous records.The flexible all-solid-state supercapacitor assembled by the films had an outstanding volumetric capacitance of 97.8 F cm^(-3)and an energy density of 8.7 mWh cm^(-3),which is best one for pure PEDOT:PSS-based supercapacitors.Grazing-incidence wide-angle X-ray scattering,X-ray photoelectron spectroscopy,and other characterizations were carried out to characterize the structure evolution.This work offers an effective novel method for conducting polymer morphology control and promotes PEDOT:PSS applications in energy storage field.展开更多
Atmospheric particle adsorption on insulator surfaces,coupled with humid environments,significantly affects contamination flashover,necessitating a clear understanding of the electric field distribution on insulator s...Atmospheric particle adsorption on insulator surfaces,coupled with humid environments,significantly affects contamination flashover,necessitating a clear understanding of the electric field distribution on insulator surfaces with adsorbed particles.This is crucial for accurately assessing insulator safety and informing critical decision-making.Although previous research has demonstrated that particle arrangement significantly influences the electric field distribution around transmission lines,an in-depth analysis of its effects on insulator surfaces remains lacking.To address this gap,this study establishes a composite insulator model to examine how three types of spherical contamination layers affect the electric field distribution on insulator surfaces under varying environmental conditions.The results reveal that in dry environments,the electric field strength at the apex of single-particle contamination layers increases with the particle size and relative permittivity.For the double-particle contamination layers,the electric field intensity on the insulator surface decreases as the particle spacing increases,and larger particles are more likely to attract smaller charged particles.For triple-particle contamination layers arranged in a triangular pattern,the maximum surface field strength is nearly double that of the chain-arranged particles.Furthermore,within the chain-arranged triple-particle contamination layers,a large-small-large size arrangement has a more pronounced impact on the surface electric field than a small-large-small size arrangement.In humid environments,the surface electric field strength of insulators decreases with increasing contamination levels.These findings are of significant theoretical and practical importance for ensuring the safe operation of power systems.展开更多
Liquefied natural gas storage and transportation as well as space propulsion systems have sparked inter-est in the martensitic transformation and behaviours of 316 L stainless steels(SS)under ultra-cryogenic deformati...Liquefied natural gas storage and transportation as well as space propulsion systems have sparked inter-est in the martensitic transformation and behaviours of 316 L stainless steels(SS)under ultra-cryogenic deformation.In this study,high-resolution transmission electron microscopy(HRTEM)and molecular dy-namics(MD)simulations were used to investigate the atomic arrangements and crystalline defects of deformation-induced γ-austenite→ε-martensite→α'-martensite and γ→α'martensitic transforma-tions in 316 L SS at 15 and 173 K.Theγ→εtransformation involves the glide of Shockley partial dislocations on(111)γplanes without a change in atomic spacing.The formation of anα'inclusion in a singleε-band is achieved by a continuous lattice distortion,accompanied by the formation of a tran-sition zone ofα'and the expansion of the average atomic spacings due to dislocation shuffling.Asα'grows further intoγ,the orientation relationship(OR)of theα'changes by lattice bending.This pro-cess follows the Bogers-Burgers-Olson-Cohen model despite it not occurring on intersecting shear bands.Stacking faults and twins can also serve as nucleation sites forα'at 173 K.We also found that direct transformation of γ→α'occurs by the glide of √6aγ[11(2)]/12 dislocations on every(111)γplane with misfit dislocations.Overall,this study provides,for the first time,insights into the atomic-scale mech-anisms of various two-step and one-step martensitic transformations induced by cryogenic deformation and corresponding local strain,enhancing our understanding of the role of martensitic transformation under ultra-cryogenic-temperature deformation in controlling the properties.展开更多
The miniaturization and high-power density of electronic devices presents new challenges in thermal management.The precise control of microstructure arrangement,particularly in boron nitride nanosheets(BNNS),is essent...The miniaturization and high-power density of electronic devices presents new challenges in thermal management.The precise control of microstructure arrangement,particularly in boron nitride nanosheets(BNNS),is essential for achieving efficient heat dissipation in highly thermally conductive composites within electrically insulating package.In this work,manganese ferrite was hydrothermally synthesized on BNNS,creating a layered structure in a magnetically responsive nanohybrid material named BNNS@M.This material was then integrated into a waterborne polyurethane(WPU)solution and shaped under a magnetic field to produce thermally conductive film.By altering the magnetic field direction,the mi-crostructure orientation of BNNS@M was controlled,resulting in anisotropic thermally conductive com-posite films with horizontal and vertical orientations.Specifically,under a vertical magnetic field,the film 30-Ve-BNNS@WPU,containing 30 wt.%BNNS@M,achieved a through-plane thermal conductivity of 8.5 W m^(−1)K^(−1)and an in-plane thermal conductivity of 1.8 W m^(−1)K^(−1),showcasing significant anisotropic thermal conductivity.Meanwhile,these films demonstrated excellent thermal stability,mechanical per-formance,and flame retardancy.Furthermore,employing Foygel’s theory elucidated the impact of filler arrangement on thermal conductivity mechanisms and the actual application of 5 G device chips and LED lamps emphasizing the potential of these thermally conductive films in thermal management appli-cations.This investigation contributes valuable design concepts and foundations for the development of anisotropic thermally conductive composites suitable for electron thermal management.展开更多
The lack of systematic and scientific top-level arrangement in the field of civil aircraft flight test leads to the problems of long duration and high cost.Based on the flight test activity,mathematical models of flig...The lack of systematic and scientific top-level arrangement in the field of civil aircraft flight test leads to the problems of long duration and high cost.Based on the flight test activity,mathematical models of flight test duration and cost are established to set up the framework of flight test process.The top-level arrangement for flight test is optimized by multi-objective algorithm to reduce the duration and cost of flight test.In order to verify the necessity and validity of the mathematical models and the optimization algorithm of top-level arrangement,real flight test data is used to make an example calculation.Results show that the multi-objective optimization results of the top-level flight arrangement are better than the initial arrangement data,which can shorten the duration,reduce the cost,and improve the efficiency of flight test.展开更多
In nature,cavitation bubbles typically appear in clusters,engaging in interactions that create a variety of dynamicmotion patterns.To better understand the behavior ofmultiple bubble collapses and the mechanisms of in...In nature,cavitation bubbles typically appear in clusters,engaging in interactions that create a variety of dynamicmotion patterns.To better understand the behavior ofmultiple bubble collapses and the mechanisms of interbubble interaction,this study employs molecular dynamics simulation combined with a coarse-grained force field.By focusing on collapsemorphology,local density,and pressure,it elucidates how the number and arrangement of bubbles influence the collapse process.The mechanisms behind inter-bubble interactions are also considered.The findings indicate that the collapse speed of unbounded bubbles located in lateral regions is greater than that of the bubbles in the center.Moreover,it is shown that asymmetrical bubble distributions lead to a shorter collapse time overall.展开更多
1T-MoS_(2)nanosheets,with metallic conductivity and high capacity,hold great potential for lithium-ion capacitors(LICs),but suffer from sluggish reaction kinetics due to dense stacking.Herein,1T-MoS_(2)nanosheets with...1T-MoS_(2)nanosheets,with metallic conductivity and high capacity,hold great potential for lithium-ion capacitors(LICs),but suffer from sluggish reaction kinetics due to dense stacking.Herein,1T-MoS_(2)nanosheets with enlarged interlayer spacing,vertically bonded to reduced graphene oxide(rGO)(1T-MoS_(2)/rGO),were designed using a hydrothermal-assisted dispersion and intercalation strategy.The active nitrogen species derived from N,N-dimethylformamide(DMF)not only bridge the rGO and MoS_(2)through strong Mo-N-C bonds to promote the formation of dispersed MoS_(2)nanosheets,but also intercalate into the MoS_(2)structure,further enlarging the interlayer spacing.This unique structure synergistically enhances meso-and microscale mass transfer outside and inside of the few-layered nanosheets,significantly improving electrochemical reaction kinetics and reducing the kinetic mismatch between the anode and cathode.Consequently,the resulting 1T-MoS_(2)/rGO achieves a capacity of 500 mAh g^(-1)after 500 cycles at 5 A g^(-1)and a high rate performance of 587 mAh g^(-1)at a high rate of 10 A g^(-1).Moreover,the assembled 3D vertical 1T-MoS_(2)/rGO//AC LIC delivers a high energy density of 100.3 Wh kg^(-1)at a power density of1.0 kW kg^(-1),and long cycle stability with capacity retention as high as 91.02%after 5000 cycles at 2 A g^(-1).This work provides a generalizable strategy for engineering two-dimensional material-based electrodes,offering new insights into high-performance energy storage systems.展开更多
The migration and transformation of hexavalent chromium(Cr(VI))in the environment are regulated by pyrite(FeS2).However,variations in pyrite crystal facets influence the adsorption behavior and electron transfer betwe...The migration and transformation of hexavalent chromium(Cr(VI))in the environment are regulated by pyrite(FeS2).However,variations in pyrite crystal facets influence the adsorption behavior and electron transfer between pyrite and Cr(VI),thereby impacting the Cr(VI)reduction performance.Herein,two naturally common facets of pyritewere synthesized hydrothermally to investigate the facet-dependent mechanisms of Cr(VI)reduction.The experimental results revealed that the{111}facet exhibited approximately 1.30–1.50 times higher efficiency in Cr(VI)reduction compared to the{100}facet.Surface analyses and electrochemical results indicated that{111}facet displayed a higher iron-sulfur oxidation level,which was affected by its superior electrochemical properties during the reaction with Cr(VI).Density functional theory(DFT)calculations demonstrated that the narrower band gap and lower work function on{111}facet were more favorable for the electron transfer between Fe(II)and Cr(VI).Furthermore,different adsorption configurations were observed on{100}and{111}surfaces due to the unique arrangements of Fe and S atoms.Specifically,O atoms in Cr_(2)O_(7)^(2−)directly bound with the S sites on{100}but the Fe sites on{111}.According to the density of states(DOS),the Fe site had better reactivity than the S site in the reaction,which appeared to be related to the fracture of S-S bonds.Additionally,the adsorption configuration of Cr_(2)O_(7)^(2−)on{111}surface showed a stronger adsorption energy and a more stable coordination mode,favoring subsequent Cr(VI)reduction process.These findings provide an in-depth analysis of facet-dependent mechanisms underlying Cr(VI)reduction behavior,offering new insights into studying environmental interactions between heavy metals and natural minerals.展开更多
Finding an optimal isolator arrangement for asymmetric structures using traditional conceptual design methods that can significantly minimize torsional response while ensuring efficient horizontal seismic isolation is...Finding an optimal isolator arrangement for asymmetric structures using traditional conceptual design methods that can significantly minimize torsional response while ensuring efficient horizontal seismic isolation is cumbersome and inefficient.Thus,this work develops a multi-objective optimization method to enhance the torsional resistance of asymmetric base-isolated structures.The primary objective is to simultaneously minimize the interstory rotation of the superstructure,the rotation of the isolation layer,and the interstory displacement of the superstructure without exceeding the isolator displacement limits.A fast non-dominated sorting genetic algorithm(NSGA-Ⅱ)is employed to satisfy this optimization objective.Subsequently,the isolator arrangement,encompassing both positions and categories,is optimized according to this multi-objective optimization method.Additionally,an optimization design platform is developed to streamline the design operation.This platform integrates the input of optimization parameters,the output of optimization results,the finite element analysis,and the multi-objective optimization method proposed herein.Finally,the application of this multi-objective optimization method and its associated platform are demonstrated on two asymmetric base-isolated structures of varying heights and plan configurations.The results indicate that the optimal isolator arrangement derived from the optimization method can further improve the control over the lateral and torsional responses of asymmetric base-isolated structures compared to conventional conceptual design methods.Notably,the interstory rotation of the optimal base-isolated structure is significantly reduced,constituting only approximately 33.7%of that observed in the original base-isolated structure.The proposed platform facilitates the automatic generation of the optimal design scheme for the isolators of asymmetric base-isolated structures,offering valuable insights and guidance for the burgeoning field of intelligent civil engineering design.展开更多
The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinatio...The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinations of them were considered.The leaf-shaped design of the cooling pin fin enhances uniformity and synergy,effectively creating an optimized flow path that boosts cooling performance.Eight three-dimensional conjugate heat transfer models in staggered arrangement were developed using ANSYS-Fluent software.Aluminum6061material was used as the heat sinkmaterial and single-phase liquid water flowed through the rectangular channel where the Reynolds(R_(e))number varies from 40 to 100.Using the same boundary conditions as the software simulations,two leaf-shaped channels were printed to validate numerical models.Velocity field and temperature differences of the eight proposed leaf-shaped pin fins configurations were discussed by comparison with cylindrical pin fins.Based on the findings of this study,at a Reynolds number of 80,the Leaf B Staggered Array(LBSA)records a maximum temperature that is 0.72 K lower than that of the cylindrical pin fins arrangement.Additionally,the LBSA exhibits a reduction in the friction factor by approximately 33.3%relative to the circular pin fins array under the same R_(e).This implies that the design of LBSA has been optimized to provide better heat dissipation performance while maintaining lower energy consumption.Furthermore,the LBSA demonstrates the most favorable thermal-hydraulic performance index(TPI),which is 1.18 times higher than that of the circular pin fins arrangement at R_(e)=80.The temperature reduction and friction factor reduction of the lobed channel is more pronounced than that of the conventional cooling channel,highlighting its potential to increase heat transfer efficiency and reduce energy consumption in practical applications.展开更多
The flow field architecture of the proton exchange membrane fuel cell(PEMFC)cathode critically determines its performance.To enhance PEMFC operation through structural optimization,trapezoidal obstacles were implement...The flow field architecture of the proton exchange membrane fuel cell(PEMFC)cathode critically determines its performance.To enhance PEMFC operation through structural optimization,trapezoidal obstacles were implemented in the cathode flow channels.The height dependence of these obstacles was systematically investigated,revealing that a 0.7 mm obstacle height enhanced mass transfer from channels to the gas diffusion layer(GDL)compared to conventional triple-serpentine designs.This configuration achieved a 12.08%increase in limiting current density alongside improved water management.Subsequent studies on obstacle distribution density identified 75%density as optimal,delivering maximum net power density with 10.6%lower pressure drop than full-density arrangements.展开更多
The main purpose of this research is to optimize the hydrothermal performance of a dimpled tube by augmenting the surface area for heat transmission and thermal layer cracking.To achieve that,the impact of different d...The main purpose of this research is to optimize the hydrothermal performance of a dimpled tube by augmenting the surface area for heat transmission and thermal layer cracking.To achieve that,the impact of different dimple diameters and their distribution along the dimpled tube was investigated numerically using the ANSYS Fluent 2022 R1 software by considering two models,A and B.Both models consist of three regions;the first,second,and third have dimple diameters of 3,2,&1 mm,respectively.Model A included an in-line dimple arrangement,while model B involved a staggered dimple arrangement.The finite volume method(FVM)was used in the modeling techniques to address the turbulent flow problem,which ranged in this investigation from Re of 3000 to 8000.The cooling fluid used in this investigation is water,which concentrated primarily on single-phase flow conditions.The investigation results revealed that as the Re increased,all analyzed models showcased higher.A reduction in pressure drops,thermal resistance,Nu,and overall performance standards.Crucially,compared to the traditionalmodel,both suggested models demonstrated improved heat transmission capacities.Within all the models examined,the tube with dimples in(model B)as staggered showed the greatest enhancement in the Nu,which was almost double that of the conventional type.Model A and Model B have respective average total performance criteria of 1.23 and 1.34.展开更多
Crystal structure prediction(CSP)is a foundational computational technique for determining the atomic arrangements of crystalline materials,especially under high-pressure conditions.While CSP plays a critical role in ...Crystal structure prediction(CSP)is a foundational computational technique for determining the atomic arrangements of crystalline materials,especially under high-pressure conditions.While CSP plays a critical role in materials science,traditional approaches often encounter significant challenges related to computational efficiency and scalability,particularly when applied to complex systems.Recent advances in machine learning(ML)have shown tremendous promise in addressing these limitations,enabling the rapid and accurate prediction of crystal structures across a wide range of chemical compositions and external conditions.This review provides a concise overview of recent progress in ML-assisted CSP methodologies,with a particular focus on machine learning potentials and generative models.By critically analyzing these advances,we highlight the transformative impact of ML in accelerating materials discovery,enhancing computational efficiency,and broadening the applicability of CSP.Additionally,we discuss emerging opportunities and challenges in this rapidly evolving field.展开更多
Multiple principal element alloys(MPEAs),also known as high-entropy alloys,have attracted significant attention because of their exceptional mechanical and thermal properties.A critical factor influencing these proper...Multiple principal element alloys(MPEAs),also known as high-entropy alloys,have attracted significant attention because of their exceptional mechanical and thermal properties.A critical factor influencing these properties is suggested to be the presence of chemical short-range order(SRO),characterized by specific atomic arrangements occurring more frequently than in a random distribution.Despite extensive efforts to elucidate SRO,particularly in face-centered cubic(fcc)3d transition metal-based MPEAs,several key aspects remain under debate:the conditions under which SRO forms,the reliability of characterization methods for detecting SRO,and its quantitative impact on mechanical performance.This review summarizes the challenges and unresolved issues in this emerging field,drawing comparisons with well-established research on SRO in binary alloys over the past few decades.Through this cross-system comparison,we aim to provide new insights into SRO from a comprehensive perspective.展开更多
This paper grasps the research theme of artificial intelligence(AI)and human intelligence(HI)synergy to create value,and analyzes the development status of AI and HI in the current context of digital intelligence,as w...This paper grasps the research theme of artificial intelligence(AI)and human intelligence(HI)synergy to create value,and analyzes the development status of AI and HI in the current context of digital intelligence,as well as the significance of their synergy to empower value creation.At the same time,the theory of resource arrangement is introduced,and the connotation and composition of the theory are summarized,as well as the development in the field of research and application.This paper focuses on revealing the intrinsic relationship between resource orchestration theory and AI and HI collaborative work,aiming to fully explore the potential of resource orchestration theory in the collaborative innovation of AI and HI,and put forward practical suggestions based on this.展开更多
The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,pr...The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,promoting conventional intercropping strategies in modern agriculture can prove challenging.The innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a solution.This system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable agriculture.In this article,we provide an overview of SMSI and explain how it differs from traditional intercropping.We also discuss the core principles that foster higher yields and the prospects for its future development.展开更多
Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflector...Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further investigation.To date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster prevention.To investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without deflectors.This model was validated using laboratory flume test data from the literature.Then,the model was used to investigate the influence of the deflector angle and multi-barrier arrangements.The optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow mechanisms.The investigation considered the energy dissipation process,retention efficiency,and dead-zone formation.Compared with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris flow.Recommendations for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters.展开更多
文摘WANG Jiarui runs a small building material store in Yiwu, east China＇s Zhejiang Province. When he started his business 10 years ago, getting financing was a major headache. ＂I had to begin my enterprise by borrowing money from all my friends and relatives,＂ said the entrepreneur. In the years since then, the situation has improved Rradually.
基金Philosophy and Social Science Planning Projects in Yunnan Province,No.QN202428China Postdoctoral Science Foundation,No.2024M752918。
文摘Foreign-funded overseas industrial parks(OIPs)are crucial for attracting foreign investment and promoting globalization in developing countries.However,large-scale land acquisition for these parks generates conflicts between developers and local stakeholders,increasing development costs.A qualitative multicase study was conducted in this study to analyze the land transaction trajectories of China's OIPs.Four OIPs were selected to reveal the underlying mechanisms from the perspectives of institutional arrangements,governance mechanisms,and enterprise heterogeneity.The findings indicate that in host countries with insufficient institutional development,local governments are more inclined to directly engage in OIP land acquisition.High-level intergovernmental mechanisms facilitate land acquisition processes,although their efficacy depends largely on administrative power allocation across parks in host countries.The results also indicate that enterprise characteristics significantly influence land acquisition,where microscale private enterprises lacking political connections often employ low-cost,bottom-up strategies by leveraging international experience.In summary,policy-makers in developing countries should prioritize enhancing OIP governance to mitigate transaction costs,promote diversified land supply,and optimize land allocation.By depicting China's OIP land acquisition processes,this study deepens the academic understanding of OIP governance in developing countries and related international land transactions,offering practical OIP management insights for governments in both host and parent countries.
基金supported by the National Natural Science Foundation of China(No.51902134)Zhejiang Public Welfare Technology Application Research Program(No.LGJ22B040001)+1 种基金the Innovation Jiaxing Elite Leading Plan 2020,Jiaxing Public Welfare Technology Application Research Program(No.2023AY11051)the Fundamental Research Funds for the Jiaxing University(No.CD70519019,No.CDN70518005,No.CD70623018).
文摘Thick and highly conductive poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate films with ideal porous structure are fulfilling as electrodes for supercapacitors.However,the homogeneous micro-structure without the aid of templates or composite presents a significant obstacle,due to the intrinsic softness of the dominant PSS component.In this study,we have successfully developed a porous configuration by employing a solvothermal approach with ethylene glycol(EG)as the solvent.The synergistic action of elevated pressure and temperature was crucial in prompting EG to tailor the microstructure of the PEDOT:PSS films by removing non-conductive PSS chains and improving PEDOT crystallinity,and the formation of a porous network.The resulting porous PEDOT:PSS films exhibited a high conductivity of 1644 S cm^(-1)and achieved a volumetric capacitance record of 270 F cm^(-3),markedly exceeding previous records.The flexible all-solid-state supercapacitor assembled by the films had an outstanding volumetric capacitance of 97.8 F cm^(-3)and an energy density of 8.7 mWh cm^(-3),which is best one for pure PEDOT:PSS-based supercapacitors.Grazing-incidence wide-angle X-ray scattering,X-ray photoelectron spectroscopy,and other characterizations were carried out to characterize the structure evolution.This work offers an effective novel method for conducting polymer morphology control and promotes PEDOT:PSS applications in energy storage field.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12064034 and 11562017)the Leading Talents Program of Science and Technology Innovation in Ningxia Hui Autonomous Region,China(Grant No.2020GKLRLX08)the Natural Science Foundation of Ningxia Hui Autonomous Region,China(Grant No.2024AAC05040)。
文摘Atmospheric particle adsorption on insulator surfaces,coupled with humid environments,significantly affects contamination flashover,necessitating a clear understanding of the electric field distribution on insulator surfaces with adsorbed particles.This is crucial for accurately assessing insulator safety and informing critical decision-making.Although previous research has demonstrated that particle arrangement significantly influences the electric field distribution around transmission lines,an in-depth analysis of its effects on insulator surfaces remains lacking.To address this gap,this study establishes a composite insulator model to examine how three types of spherical contamination layers affect the electric field distribution on insulator surfaces under varying environmental conditions.The results reveal that in dry environments,the electric field strength at the apex of single-particle contamination layers increases with the particle size and relative permittivity.For the double-particle contamination layers,the electric field intensity on the insulator surface decreases as the particle spacing increases,and larger particles are more likely to attract smaller charged particles.For triple-particle contamination layers arranged in a triangular pattern,the maximum surface field strength is nearly double that of the chain-arranged particles.Furthermore,within the chain-arranged triple-particle contamination layers,a large-small-large size arrangement has a more pronounced impact on the surface electric field than a small-large-small size arrangement.In humid environments,the surface electric field strength of insulators decreases with increasing contamination levels.These findings are of significant theoretical and practical importance for ensuring the safe operation of power systems.
基金supported by the Henry Royce Institute for Advanced Materials,funded through Engineering and Physical Sciences Research Council(EPSRC)grants EP/R00661X/1,EP/S019367/1,EP/P025021/1,and EP/P025498/1.
文摘Liquefied natural gas storage and transportation as well as space propulsion systems have sparked inter-est in the martensitic transformation and behaviours of 316 L stainless steels(SS)under ultra-cryogenic deformation.In this study,high-resolution transmission electron microscopy(HRTEM)and molecular dy-namics(MD)simulations were used to investigate the atomic arrangements and crystalline defects of deformation-induced γ-austenite→ε-martensite→α'-martensite and γ→α'martensitic transforma-tions in 316 L SS at 15 and 173 K.Theγ→εtransformation involves the glide of Shockley partial dislocations on(111)γplanes without a change in atomic spacing.The formation of anα'inclusion in a singleε-band is achieved by a continuous lattice distortion,accompanied by the formation of a tran-sition zone ofα'and the expansion of the average atomic spacings due to dislocation shuffling.Asα'grows further intoγ,the orientation relationship(OR)of theα'changes by lattice bending.This pro-cess follows the Bogers-Burgers-Olson-Cohen model despite it not occurring on intersecting shear bands.Stacking faults and twins can also serve as nucleation sites forα'at 173 K.We also found that direct transformation of γ→α'occurs by the glide of √6aγ[11(2)]/12 dislocations on every(111)γplane with misfit dislocations.Overall,this study provides,for the first time,insights into the atomic-scale mech-anisms of various two-step and one-step martensitic transformations induced by cryogenic deformation and corresponding local strain,enhancing our understanding of the role of martensitic transformation under ultra-cryogenic-temperature deformation in controlling the properties.
基金supported by the National Natural Science Foundation of China(No.22268025)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011985)the Applied Basic Research Program of Yunnan Province(Nos.202201AT070115,202201BE070001–031).
文摘The miniaturization and high-power density of electronic devices presents new challenges in thermal management.The precise control of microstructure arrangement,particularly in boron nitride nanosheets(BNNS),is essential for achieving efficient heat dissipation in highly thermally conductive composites within electrically insulating package.In this work,manganese ferrite was hydrothermally synthesized on BNNS,creating a layered structure in a magnetically responsive nanohybrid material named BNNS@M.This material was then integrated into a waterborne polyurethane(WPU)solution and shaped under a magnetic field to produce thermally conductive film.By altering the magnetic field direction,the mi-crostructure orientation of BNNS@M was controlled,resulting in anisotropic thermally conductive com-posite films with horizontal and vertical orientations.Specifically,under a vertical magnetic field,the film 30-Ve-BNNS@WPU,containing 30 wt.%BNNS@M,achieved a through-plane thermal conductivity of 8.5 W m^(−1)K^(−1)and an in-plane thermal conductivity of 1.8 W m^(−1)K^(−1),showcasing significant anisotropic thermal conductivity.Meanwhile,these films demonstrated excellent thermal stability,mechanical per-formance,and flame retardancy.Furthermore,employing Foygel’s theory elucidated the impact of filler arrangement on thermal conductivity mechanisms and the actual application of 5 G device chips and LED lamps emphasizing the potential of these thermally conductive films in thermal management appli-cations.This investigation contributes valuable design concepts and foundations for the development of anisotropic thermally conductive composites suitable for electron thermal management.
基金supported by the National Natural Science Foundation of China(62073267,61903305)the Fundamental Research Funds for the Central Universities(HXGJXM202214).
文摘The lack of systematic and scientific top-level arrangement in the field of civil aircraft flight test leads to the problems of long duration and high cost.Based on the flight test activity,mathematical models of flight test duration and cost are established to set up the framework of flight test process.The top-level arrangement for flight test is optimized by multi-objective algorithm to reduce the duration and cost of flight test.In order to verify the necessity and validity of the mathematical models and the optimization algorithm of top-level arrangement,real flight test data is used to make an example calculation.Results show that the multi-objective optimization results of the top-level flight arrangement are better than the initial arrangement data,which can shorten the duration,reduce the cost,and improve the efficiency of flight test.
基金funded by the Natural Science Foundation of China[U20A20292]Shandong Province Science andTechnology SMES InnovationAbility Improvement Project[2023TSGC0005]China Postdoctoral Science Foundation[2024M752697].
文摘In nature,cavitation bubbles typically appear in clusters,engaging in interactions that create a variety of dynamicmotion patterns.To better understand the behavior ofmultiple bubble collapses and the mechanisms of interbubble interaction,this study employs molecular dynamics simulation combined with a coarse-grained force field.By focusing on collapsemorphology,local density,and pressure,it elucidates how the number and arrangement of bubbles influence the collapse process.The mechanisms behind inter-bubble interactions are also considered.The findings indicate that the collapse speed of unbounded bubbles located in lateral regions is greater than that of the bubbles in the center.Moreover,it is shown that asymmetrical bubble distributions lead to a shorter collapse time overall.
基金the financial support from the National Natural Science Foundation of China(No.52225208 and 51802131)the Training Program for academic and technical leaders in major disciplines of Jiangxi Province-Young Talents(No.20212BCJ23021)the Natural Science Foundation of Jiangxi Province,China(No.20232BAB204020).
文摘1T-MoS_(2)nanosheets,with metallic conductivity and high capacity,hold great potential for lithium-ion capacitors(LICs),but suffer from sluggish reaction kinetics due to dense stacking.Herein,1T-MoS_(2)nanosheets with enlarged interlayer spacing,vertically bonded to reduced graphene oxide(rGO)(1T-MoS_(2)/rGO),were designed using a hydrothermal-assisted dispersion and intercalation strategy.The active nitrogen species derived from N,N-dimethylformamide(DMF)not only bridge the rGO and MoS_(2)through strong Mo-N-C bonds to promote the formation of dispersed MoS_(2)nanosheets,but also intercalate into the MoS_(2)structure,further enlarging the interlayer spacing.This unique structure synergistically enhances meso-and microscale mass transfer outside and inside of the few-layered nanosheets,significantly improving electrochemical reaction kinetics and reducing the kinetic mismatch between the anode and cathode.Consequently,the resulting 1T-MoS_(2)/rGO achieves a capacity of 500 mAh g^(-1)after 500 cycles at 5 A g^(-1)and a high rate performance of 587 mAh g^(-1)at a high rate of 10 A g^(-1).Moreover,the assembled 3D vertical 1T-MoS_(2)/rGO//AC LIC delivers a high energy density of 100.3 Wh kg^(-1)at a power density of1.0 kW kg^(-1),and long cycle stability with capacity retention as high as 91.02%after 5000 cycles at 2 A g^(-1).This work provides a generalizable strategy for engineering two-dimensional material-based electrodes,offering new insights into high-performance energy storage systems.
基金supported by the National Natural Science Foundation of China(No.42277256)the Natural Science Foundation of Hunan Province(No.2022JJ30710)+1 种基金Hunan Province Environmental Protection Research Program(No.HBKT-2021014)Guangdong Province Dabaoshan Mining Co.Ltd Technology Program(Semi-industrial test of 200T/time low-grade copper ore bio-heap leaching).
文摘The migration and transformation of hexavalent chromium(Cr(VI))in the environment are regulated by pyrite(FeS2).However,variations in pyrite crystal facets influence the adsorption behavior and electron transfer between pyrite and Cr(VI),thereby impacting the Cr(VI)reduction performance.Herein,two naturally common facets of pyritewere synthesized hydrothermally to investigate the facet-dependent mechanisms of Cr(VI)reduction.The experimental results revealed that the{111}facet exhibited approximately 1.30–1.50 times higher efficiency in Cr(VI)reduction compared to the{100}facet.Surface analyses and electrochemical results indicated that{111}facet displayed a higher iron-sulfur oxidation level,which was affected by its superior electrochemical properties during the reaction with Cr(VI).Density functional theory(DFT)calculations demonstrated that the narrower band gap and lower work function on{111}facet were more favorable for the electron transfer between Fe(II)and Cr(VI).Furthermore,different adsorption configurations were observed on{100}and{111}surfaces due to the unique arrangements of Fe and S atoms.Specifically,O atoms in Cr_(2)O_(7)^(2−)directly bound with the S sites on{100}but the Fe sites on{111}.According to the density of states(DOS),the Fe site had better reactivity than the S site in the reaction,which appeared to be related to the fracture of S-S bonds.Additionally,the adsorption configuration of Cr_(2)O_(7)^(2−)on{111}surface showed a stronger adsorption energy and a more stable coordination mode,favoring subsequent Cr(VI)reduction process.These findings provide an in-depth analysis of facet-dependent mechanisms underlying Cr(VI)reduction behavior,offering new insights into studying environmental interactions between heavy metals and natural minerals.
基金National Natural Science Foundation of China under Grant No.52278490。
文摘Finding an optimal isolator arrangement for asymmetric structures using traditional conceptual design methods that can significantly minimize torsional response while ensuring efficient horizontal seismic isolation is cumbersome and inefficient.Thus,this work develops a multi-objective optimization method to enhance the torsional resistance of asymmetric base-isolated structures.The primary objective is to simultaneously minimize the interstory rotation of the superstructure,the rotation of the isolation layer,and the interstory displacement of the superstructure without exceeding the isolator displacement limits.A fast non-dominated sorting genetic algorithm(NSGA-Ⅱ)is employed to satisfy this optimization objective.Subsequently,the isolator arrangement,encompassing both positions and categories,is optimized according to this multi-objective optimization method.Additionally,an optimization design platform is developed to streamline the design operation.This platform integrates the input of optimization parameters,the output of optimization results,the finite element analysis,and the multi-objective optimization method proposed herein.Finally,the application of this multi-objective optimization method and its associated platform are demonstrated on two asymmetric base-isolated structures of varying heights and plan configurations.The results indicate that the optimal isolator arrangement derived from the optimization method can further improve the control over the lateral and torsional responses of asymmetric base-isolated structures compared to conventional conceptual design methods.Notably,the interstory rotation of the optimal base-isolated structure is significantly reduced,constituting only approximately 33.7%of that observed in the original base-isolated structure.The proposed platform facilitates the automatic generation of the optimal design scheme for the isolators of asymmetric base-isolated structures,offering valuable insights and guidance for the burgeoning field of intelligent civil engineering design.
基金supported by the Shandong Provincial Natural Science Foundation,China(Grant ZR2024ME136).
文摘The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinations of them were considered.The leaf-shaped design of the cooling pin fin enhances uniformity and synergy,effectively creating an optimized flow path that boosts cooling performance.Eight three-dimensional conjugate heat transfer models in staggered arrangement were developed using ANSYS-Fluent software.Aluminum6061material was used as the heat sinkmaterial and single-phase liquid water flowed through the rectangular channel where the Reynolds(R_(e))number varies from 40 to 100.Using the same boundary conditions as the software simulations,two leaf-shaped channels were printed to validate numerical models.Velocity field and temperature differences of the eight proposed leaf-shaped pin fins configurations were discussed by comparison with cylindrical pin fins.Based on the findings of this study,at a Reynolds number of 80,the Leaf B Staggered Array(LBSA)records a maximum temperature that is 0.72 K lower than that of the cylindrical pin fins arrangement.Additionally,the LBSA exhibits a reduction in the friction factor by approximately 33.3%relative to the circular pin fins array under the same R_(e).This implies that the design of LBSA has been optimized to provide better heat dissipation performance while maintaining lower energy consumption.Furthermore,the LBSA demonstrates the most favorable thermal-hydraulic performance index(TPI),which is 1.18 times higher than that of the circular pin fins arrangement at R_(e)=80.The temperature reduction and friction factor reduction of the lobed channel is more pronounced than that of the conventional cooling channel,highlighting its potential to increase heat transfer efficiency and reduce energy consumption in practical applications.
文摘The flow field architecture of the proton exchange membrane fuel cell(PEMFC)cathode critically determines its performance.To enhance PEMFC operation through structural optimization,trapezoidal obstacles were implemented in the cathode flow channels.The height dependence of these obstacles was systematically investigated,revealing that a 0.7 mm obstacle height enhanced mass transfer from channels to the gas diffusion layer(GDL)compared to conventional triple-serpentine designs.This configuration achieved a 12.08%increase in limiting current density alongside improved water management.Subsequent studies on obstacle distribution density identified 75%density as optimal,delivering maximum net power density with 10.6%lower pressure drop than full-density arrangements.
文摘The main purpose of this research is to optimize the hydrothermal performance of a dimpled tube by augmenting the surface area for heat transmission and thermal layer cracking.To achieve that,the impact of different dimple diameters and their distribution along the dimpled tube was investigated numerically using the ANSYS Fluent 2022 R1 software by considering two models,A and B.Both models consist of three regions;the first,second,and third have dimple diameters of 3,2,&1 mm,respectively.Model A included an in-line dimple arrangement,while model B involved a staggered dimple arrangement.The finite volume method(FVM)was used in the modeling techniques to address the turbulent flow problem,which ranged in this investigation from Re of 3000 to 8000.The cooling fluid used in this investigation is water,which concentrated primarily on single-phase flow conditions.The investigation results revealed that as the Re increased,all analyzed models showcased higher.A reduction in pressure drops,thermal resistance,Nu,and overall performance standards.Crucially,compared to the traditionalmodel,both suggested models demonstrated improved heat transmission capacities.Within all the models examined,the tube with dimples in(model B)as staggered showed the greatest enhancement in the Nu,which was almost double that of the conventional type.Model A and Model B have respective average total performance criteria of 1.23 and 1.34.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1402304)the National Natural Science Foundation of China(Grant Nos.12034009,12374005,52288102,52090024,and T2225013)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Program for JLU Science and Technology Innovative Research Team.
文摘Crystal structure prediction(CSP)is a foundational computational technique for determining the atomic arrangements of crystalline materials,especially under high-pressure conditions.While CSP plays a critical role in materials science,traditional approaches often encounter significant challenges related to computational efficiency and scalability,particularly when applied to complex systems.Recent advances in machine learning(ML)have shown tremendous promise in addressing these limitations,enabling the rapid and accurate prediction of crystal structures across a wide range of chemical compositions and external conditions.This review provides a concise overview of recent progress in ML-assisted CSP methodologies,with a particular focus on machine learning potentials and generative models.By critically analyzing these advances,we highlight the transformative impact of ML in accelerating materials discovery,enhancing computational efficiency,and broadening the applicability of CSP.Additionally,we discuss emerging opportunities and challenges in this rapidly evolving field.
基金supported by the Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments,China(Grant No.22dz2260800)the Shanghai Science and Technology Committee,China(Grant No.22JC1410300).
文摘Multiple principal element alloys(MPEAs),also known as high-entropy alloys,have attracted significant attention because of their exceptional mechanical and thermal properties.A critical factor influencing these properties is suggested to be the presence of chemical short-range order(SRO),characterized by specific atomic arrangements occurring more frequently than in a random distribution.Despite extensive efforts to elucidate SRO,particularly in face-centered cubic(fcc)3d transition metal-based MPEAs,several key aspects remain under debate:the conditions under which SRO forms,the reliability of characterization methods for detecting SRO,and its quantitative impact on mechanical performance.This review summarizes the challenges and unresolved issues in this emerging field,drawing comparisons with well-established research on SRO in binary alloys over the past few decades.Through this cross-system comparison,we aim to provide new insights into SRO from a comprehensive perspective.
文摘This paper grasps the research theme of artificial intelligence(AI)and human intelligence(HI)synergy to create value,and analyzes the development status of AI and HI in the current context of digital intelligence,as well as the significance of their synergy to empower value creation.At the same time,the theory of resource arrangement is introduced,and the connotation and composition of the theory are summarized,as well as the development in the field of research and application.This paper focuses on revealing the intrinsic relationship between resource orchestration theory and AI and HI collaborative work,aiming to fully explore the potential of resource orchestration theory in the collaborative innovation of AI and HI,and put forward practical suggestions based on this.
基金supported by the National Natural Science Foundation of China(31971853)。
文摘The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,promoting conventional intercropping strategies in modern agriculture can prove challenging.The innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a solution.This system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable agriculture.In this article,we provide an overview of SMSI and explain how it differs from traditional intercropping.We also discuss the core principles that foster higher yields and the prospects for its future development.
基金supported by the National Natural Science Foundation of China(Grant Nos.42120104008 and 42207198).
文摘Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further investigation.To date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster prevention.To investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without deflectors.This model was validated using laboratory flume test data from the literature.Then,the model was used to investigate the influence of the deflector angle and multi-barrier arrangements.The optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow mechanisms.The investigation considered the energy dissipation process,retention efficiency,and dead-zone formation.Compared with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris flow.Recommendations for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters.
