The Reliability-Based Design Optimization(RBDO)of complex engineering structures considering uncertainties has problems of being high-dimensional,highly nonlinear,and timeconsuming,which requires a significant amount ...The Reliability-Based Design Optimization(RBDO)of complex engineering structures considering uncertainties has problems of being high-dimensional,highly nonlinear,and timeconsuming,which requires a significant amount of sampling simulation computation.In this paper,a basis-adaptive Polynomial Chaos(PC)-Kriging surrogate model is proposed,in order to relieve the computational burden and enhance the predictive accuracy of a metamodel.The active learning basis-adaptive PC-Kriging model is combined with a quantile-based RBDO framework.Finally,five engineering cases have been implemented,including a benchmark RBDO problem,three high-dimensional explicit problems,and a high-dimensional implicit problem.Compared with Support Vector Regression(SVR),Kriging,and polynomial chaos expansion models,results show that the proposed basis-adaptive PC-Kriging model is more accurate and efficient for RBDO problems of complex engineering structures.展开更多
With the rapid development of science and technology,the application of intelligent technology in the field of civil engineering is more extensive,especially in the safety evaluation and management of engineering stru...With the rapid development of science and technology,the application of intelligent technology in the field of civil engineering is more extensive,especially in the safety evaluation and management of engineering structures.This paper discusses the role of intelligent technologies(such as artificial intelligence,Internet of Things,BIM,big data analysis,etc.)in the monitoring,evaluation,and maintenance of engineering structure safety.By studying the principle,application scenarios,and advantages of intelligent technology in structural safety evaluation,this paper summarizes how intelligent technology can improve engineering management efficiency and reduce safety risks,and puts forward the trend and challenge of future development.展开更多
Kinked rebar is a special type of steel material,which is installed in beam column nodes and frame beams.It effectively enhances the blast resilience,seismic collapse resistance,and progressive collapse resistance of ...Kinked rebar is a special type of steel material,which is installed in beam column nodes and frame beams.It effectively enhances the blast resilience,seismic collapse resistance,and progressive collapse resistance of reinforced concrete(RC)structures without imposing substantial cost burdens,thereby emerging as a focal point of recent research endeavors.On the basis of explaining the working principle of kinked rebars,this paper reviews the research status of kinked rebars at home and abroad from three core domains:the tensile mechanical properties of kinked rebars,beam column nodes with kinked rebars,and concrete frame structures with kinked rebars.The analysis underscores that the straightening process of kinked rebars does not compromise their ultimate strength but significantly bolsters structural ductility and enhances energy dissipation capabilities.In beam-column joints,the incorporation of kinked rebars facilitates the seamless transfer of plastic hinges,adhering to the design principle of“strong columns and weak beams.”In addition,kinked rebars can greatly improve the resistance of the beam;The seismic resistance,internal explosion resistance,and progressive collapse resistance of reinforced concrete frame structures with kinked rebar have significantly improved.Beyond its primary application,the principle of kinked rebar was extended to other applications of kinked materials such as corrugated steel plates and origami structures,and the stress characteristics of related components and structures were studied.Intriguingly,this paper also proposes the application of kinked rebars in bridge engineering,aiming to address the challenges of localized damage concentration and excessive residual displacement in RC bridge piers.The introduction of kinked rebars in piers is envisioned to mitigate these issues,with the paper outlining its advantages and feasibility,thereby offering valuable insights for future research on kinked reinforcement and seismic design strategies for bridges.展开更多
In civil engineering, the nonlinear dynamic instability of structures occurs at a bifurcation point or a limit point. The instability at a bifurcation point can be analyzed with the theory of nonlinear dynamics, and t...In civil engineering, the nonlinear dynamic instability of structures occurs at a bifurcation point or a limit point. The instability at a bifurcation point can be analyzed with the theory of nonlinear dynamics, and that at a limit point can be discussed with the theory of elastoplasticity. In this paper, the nonlinear dynamic instability of structures was treated with mathematical and mechanical theories. The research methods for the problems of structural nonlinear dynamic stability were discussed first, and then the criterion of stability or instability of structures, the method to obtain the bifurcation point and the limit point, and the formulae of the directions of the branch solutions at a bifurcation point were elucidated. These methods can be applied to the problems of nonlinear dynamic instability of structures such as reticulated shells, space grid structures, and so on. Key words nonlinear dynamic instability - engineering structures - non-stationary nonlinear system - bifurcation point - instability at a bifurcation point - limit point MSC 2000 74K25 Project supported by the Science Foundation of Shanghai Municipal Commission of Education (Grant No. 02AK04), the Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No. 02ZA14034)展开更多
Topometric auscultation is used to monitor the durability of structures, measure deformations linked to the structure of a structure or to the movement of the ground over a part of the globe, set up warning systems, e...Topometric auscultation is used to monitor the durability of structures, measure deformations linked to the structure of a structure or to the movement of the ground over a part of the globe, set up warning systems, etc. It first appeared as a visual method and rapidly evolved through the various techniques used. Some of these techniques using topography are used in several fields (civil engineering, geodesy, topography, mechanics, nuclear engineering, hydraulics, physics, etc.). These topometric techniques have undergone major changes as a result of technological advances, growing needs in the monitoring of movements or deformations, increased requirements and new challenges. The methodology adopted depends on the measuring instrument used, the parameters to be estimated and access to the area to be measured. There are two types of methods: destructive and non-destructive. In addition to the visual method, they can also be classified as mechanical, physico-chemical, dynamometric, electrophysical and geometric. The estimated parameter varies according to the methodology adopted. It can be defined by coordinates, distances, potential, electrical resistance, etc.展开更多
Constrained by severe bulk charge recombination,the actual photocurrent density of tantalum nitride(Ta_(3)N_(5))photoanode is much lower than the theoretical maximum value.Herein,we report the doping of phosphorus,a n...Constrained by severe bulk charge recombination,the actual photocurrent density of tantalum nitride(Ta_(3)N_(5))photoanode is much lower than the theoretical maximum value.Herein,we report the doping of phosphorus,a non-metallic element distinct from oxygen,into Ta_(3)N_(5),resulting in a photocurrent density 9 times higher than that of pristine Ta_(3)N_(5).Systematic characterization reveals that the phosphorus doping simultaneously enhances the bulk charge separation efficiency and surface charge injection efficiency of Ta_(3)N_(5),and induces favorable band energy restructuring.Specifically,a type-II homojunction formed between phosphorus-doped near-surface region and bulk Ta_(3)N_(5) effectively promotes the separation and transfer of photogenerated holes and electrons.Further modification with a Ni Fe-based cocatalyst enables the optimized photoanode to deliver a photocurrent density of 10 mA/cm^(2) at 1.23 V versus the reversible hydrogen electrode(RHE)and an applied bias photo-to-current efficiency of 1.78%at 0.95 V versus RHE.Our work provides a foundation for the development of a broader range of non-metal doped semiconductors.展开更多
The conversion of carbon dioxide(CO_(2))into hydrocarbons through electrochemical CO_(2)reduction reaction(eCO_(2)RR)shows a promising method to reduce CO_(2)levels and decrease reliance on fossil fuels in the years t...The conversion of carbon dioxide(CO_(2))into hydrocarbons through electrochemical CO_(2)reduction reaction(eCO_(2)RR)shows a promising method to reduce CO_(2)levels and decrease reliance on fossil fuels in the years to come.Copper-based electrocatalysts exhibit a pronounced inclination for C-C coupling,drawing considerable interest as a favored metal catalyst for generating C_(2+)products through CO_(2)RR.However,CO_(2)RR still has some obstacles including product selectivity,higher overpotential,low Faradic efficiency(FE),stability,and current density(CD).Therefore,advancement in this field enables us to comprehend the complex multi-proton electron transfer during C-C coupling and engineering strategies to improve FE and CD.Herein,this review presents some key features of Cu-based catalysts as an electrocatalyst for C_(2) product formation while addressing the industrial challenges that hinder commercialization of CO_(2)RR.In addition,recent strategies on Cu-based catalysts,synthesis strategies,advanced characterizations,and mechanistic investigations via theoretical simulations have been presented.Furthermore,recent approaches towards the composition,oxidation states,and active facets have been presented.Thus,the most favorable mechanism and possible pathways to synthesize C_(2+)products have been explained using theoretical calculations.展开更多
Silicon(Si)-based anodes have emerged as promising candidates for the next-generation lithium-ion batteries(LIBs)due to their high theoretical capacity(4200 mAh g^(-1)).However,their further application is hindered by...Silicon(Si)-based anodes have emerged as promising candidates for the next-generation lithium-ion batteries(LIBs)due to their high theoretical capacity(4200 mAh g^(-1)).However,their further application is hindered by critical challenges,including severe volume expansion(~300%),formation of unstable solid electrolyte interphase(SEI),and inherently low conductivity.While extensive research has sought to alleviate the substantial internal stress caused by volume expansion through the rational design of Si-based anode structures,the underlying mechanisms that govern these improvements remain insufficiently understood,leaving significant gaps in mechanical and interface electrical failure.To build a comprehensive understanding relationship between structural design and performance enhancement of Si-based anodes,this review first analyzes the characteristics of various Sibased anode structures and their associated internal stresses.Subsequently,it summarizes effective strategies to optimize the performance of Si-based anodes,including doping design,novel electrolyte design,and fu nctional binder design.Additionally,we assess emerging technologies with high commercial potential for structural design and interfacial modification,such as porous carbon carriers,chemical vapor deposition(CVD),spray granulation,and pre-lithiation.Finally,this work provides perspectives on the structural design of Si-based anodes.Overall,this review systematically summarizes modification strategies for Si-based anodes through structural regulation and interface engineering,thereby providing a foundation for advanced structural and interfacial design.展开更多
The NSFC Major Research Plan aims to conduct researches at the international research frontiers on modeling of strong earthquake ground motions and strong wind or typhoon fields,and investigating the damage and failur...The NSFC Major Research Plan aims to conduct researches at the international research frontiers on modeling of strong earthquake ground motions and strong wind or typhoon fields,and investigating the damage and failure evolution process of the major engineering structures under dynamic actions,focusing on the following two key scientific problems:(1)characteristics and laws of strong earthquake ground motions and strong wind or typhoon fields,and(2)process and mechanism of dynamic disaster evolution of the major engineering structures.For these goals,the research work is targeted at(1)modeling and predicting of strong earthquake ground motion and strong wind or typhoon fields,(2)identifying critical parameters influencing the dynamic disaster evolution of the major engineering structures,(3)analyzing the whole dynamic disaster evolution process of the major engineering structures,and(4)integration and verification of simulation systems for dynamic disaster evolution of the major engineering structures.展开更多
Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i...Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.展开更多
Metal halide perovskite nanostructures have emerged as low-dimensional semiconductors of great significance in many fields such as photovoltaics,photonics,and optoelectronics.Extensive efforts on the controlled synthe...Metal halide perovskite nanostructures have emerged as low-dimensional semiconductors of great significance in many fields such as photovoltaics,photonics,and optoelectronics.Extensive efforts on the controlled synthesis of perovskite nanostructures have been made towards potential device applications.The engineering of their band structures holds great promise in the rational tuning of the electronic and optical properties of perovskite nanostructures,which is one of the keys to achieving efficient and multifunctional optoelectronic devices.In this article,we summarize recent advances in band structure engineering of perovskite nanostructures.A survey of bandgap engineering of nanostructured perovskites is firstly presented from the aspects of dimensionality tailoring,compositional substitution,phase segregation and transition,as well as strain and pressure stimuli.The strategies of electronic doping are then reviewed,including defect-induced self-doping,inorganic or organic molecules-based chemical doping,and modification by metal ions or nanostructures.Based on the bandgap engineering and electronic doping,discussions on engineering energy band alignments in perovskite nanostructures are provided for building high-performance perovskite p-n junctions and heterostructures.At last,we provide our perspectives in engineering band structures of perovskite nanostructures towards future low-energy optoelectronics technologies.展开更多
Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its commercialization.These challenges in...Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its commercialization.These challenges include lithium dendrite growth in the anode side,volume change of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode side.Since the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it has also been widely discussed in addressing the abovementioned issues.In this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and summarized.Crucially,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in detail.Finally,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.展开更多
The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various field...The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.展开更多
Artificially constructed van der Waals heterostructures(vdWHs)provide an ideal platform for realizing emerging quantum phenomena in condensed matter physics.Two methods for building vdWHs have been developed:stacking ...Artificially constructed van der Waals heterostructures(vdWHs)provide an ideal platform for realizing emerging quantum phenomena in condensed matter physics.Two methods for building vdWHs have been developed:stacking two-dimensional(2D)materials into a bilayer structure with different lattice constants,or with different orientations.The interlayer coupling stemming from commensurate or incommensurate superlattice pattern plays an important role in vdWHs for modulating the band structures and generating new electronic states.In this article,we review a series of novel quantum states discovered in two model vdWH systems—graphene/hexagonal boron nitride(hBN)hetero-bilayer and twisted bilayer graphene(tBLG),and discuss how the electronic structures are modified by such stacking and twisting.We also provide perspectives for future studies on hetero-bilayer materials,from which an expansion of 2D material phase library is expected.展开更多
With the continuous development of urbanization construction, rail transit has received more and more attention. For the current subway station, the main structure of open-cut subway station plays an important role in...With the continuous development of urbanization construction, rail transit has received more and more attention. For the current subway station, the main structure of open-cut subway station plays an important role in it. Therefore, the leakage problem with high frequency should be analyzed in time and dealt with reasonably. In this paper, the construction technology of leakage treatment for the main structure of open-cut subway station is analyzed for reference.展开更多
Architectural structure engineering occupies a major position in architectural engineering and has a direct impact on the design quality of the whole building. As far as architectural structure design is concerned, sa...Architectural structure engineering occupies a major position in architectural engineering and has a direct impact on the design quality of the whole building. As far as architectural structure design is concerned, safety and durability have received more and more attention, which are also the two major focuses of current architectural structure engineering design. However, there are still some problems in carrying out these two tasks, which greatly affect the final construction quality. This paper studies the durability and safety of building structure engineering, hoping to effectively improve the overall design quality of building structure and meet the living needs.展开更多
The construction project in the actual construction process, in order to comprehensively ensure the construction quality, we should strengthen the importance of the main design of the building, and through the applica...The construction project in the actual construction process, in order to comprehensively ensure the construction quality, we should strengthen the importance of the main design of the building, and through the application of standardized construction technology, reasonable control of the construction progress and quality, to ensure the smooth progress of the follow-up work. Based on this, this paper mainly around the importance of the construction of the main structure of the building to launch an analysis, elaborated the technical application countermeasures.展开更多
It is not difficult to find out that cracks in concrete structural engineering are ubiquitous. Because the damage of the structure often begins with cracks, it brings harm and risk to social production and life. Espec...It is not difficult to find out that cracks in concrete structural engineering are ubiquitous. Because the damage of the structure often begins with cracks, it brings harm and risk to social production and life. Especially with the rapid development of my country's capital construction in recent decades, it is very necessary to understand and solve the ancient and novel problem of cracks in concrete structures. With the exploration and research of long-term engineering practice, with the continuous development of technology and productivity, people have realized that the generation of harmful cracks can be controlled through effective technical means. That is to say, through the organic combination of design and construction, the influence of cracks can be prevented from being harmful.展开更多
Supercapacitors(SCs)stand out among various energy storage devices owing to their high power density and long-term cyc-ling stability.As new two-dimensional material,MXenes have become a research hotspot in recent yea...Supercapacitors(SCs)stand out among various energy storage devices owing to their high power density and long-term cyc-ling stability.As new two-dimensional material,MXenes have become a research hotspot in recent years owing to their unique structure and rich surface functional groups.Compared with other materials,MXenes are more promising for SCs owing to their tunable precurs-ors,structural stability,and excellent electrical conductivity.However,the rate performance and electrochemical reaction activity of MXene materials are poor,and stacking severely limits their application.Therefore,various modification strategies are employed to im-prove the electrochemical performance of MXene materials.As the modification strategy of MXene electrode materials often involves in-creasing the number of ion transport channels to expose more active sites,the packing density is also affected to different degrees.There-fore,achieving a balance between high volumetric capacitance and rapid ion transport has become a key issue for the application of MXene-based SCs in wearable devices and microdevices.In this paper,the latest progress in the preparation methods and modification strategies of MXenes in recent years is reviewed with the aim of achieving both high volumetric capacitance and high ion transport for ex-panding the application of MXene-based SCs in microdevices and wearable devices.展开更多
The two-dimensional MoSe_(2)possesses a large interlayer spacing(0.65 nm)and a narrow bandgap(1.1 eV),showing potential in sodium-ion storage.However,it faces slow kinetics and volume stress during Na^(+)(de)intercala...The two-dimensional MoSe_(2)possesses a large interlayer spacing(0.65 nm)and a narrow bandgap(1.1 eV),showing potential in sodium-ion storage.However,it faces slow kinetics and volume stress during Na^(+)(de)intercalation process,thereby affecting the cycling stability and lifespan of sodium-ion batteries(SIBs).In this work,a novel approach involving anionic doping and structural design has been proposed,wherein a two-step in-situ selenization and surface thermal annealing doping process is applied to fabricate a novel configuration material of fluorine-doped MoSe_(2)@nitrogen-doped carbon nanosheets(F-MoSe_(2)@FNC).The obtained F-MoSe_(2)@FNC,benefiting from the dual advantages of structure and F-doping,synergistically promotes and accelerates the stable(de)intercalation of Na^(+).Henceforth,F-MoSe_(2)@FNC demonstrates notable characteristics in terms of reversible specific capacity,boasting a high initial coulombic efficiency of 76.97%,alongside remarkable rate capabilities and cyclic stability.The constructed F-MoSe_(2)@FNC anode-based half cell manifests exceptional longevity,enduring up to 2550 cycles at 10 A·g^(-1)with a specific capacity of 322.04 mAh·g^(-1).Its electrochemical performance surpasses that of MoSe_(2)@NC and Pure MoSe_(2),underscoring the significance of the proposed synergistic modulation.Through comprehensive kinetic analyses,encompassing in-situ electrochemical impedance spectroscopy(EIS),it is elucidated that the F-MoSe_(2)@FNC electrode showcases elevated pseudo-capacitance and rapid diffusion attributes during charge and discharge processes.Furthermore,the assembled full-cell(F-MoSe_(2)@FNC//Na_(3)V_(2)(PO_(4))_(3))attains a notable energy density of 166.94 Wh·kg^(-1).This design provides insights for the optimization of MoSe_(2)electrodes and their applications in SIBs.展开更多
基金supported by the National Key R&D Program of China(No.2021YFB1715000)the National Natural Science Foundation of China(No.52375073)。
文摘The Reliability-Based Design Optimization(RBDO)of complex engineering structures considering uncertainties has problems of being high-dimensional,highly nonlinear,and timeconsuming,which requires a significant amount of sampling simulation computation.In this paper,a basis-adaptive Polynomial Chaos(PC)-Kriging surrogate model is proposed,in order to relieve the computational burden and enhance the predictive accuracy of a metamodel.The active learning basis-adaptive PC-Kriging model is combined with a quantile-based RBDO framework.Finally,five engineering cases have been implemented,including a benchmark RBDO problem,three high-dimensional explicit problems,and a high-dimensional implicit problem.Compared with Support Vector Regression(SVR),Kriging,and polynomial chaos expansion models,results show that the proposed basis-adaptive PC-Kriging model is more accurate and efficient for RBDO problems of complex engineering structures.
文摘With the rapid development of science and technology,the application of intelligent technology in the field of civil engineering is more extensive,especially in the safety evaluation and management of engineering structures.This paper discusses the role of intelligent technologies(such as artificial intelligence,Internet of Things,BIM,big data analysis,etc.)in the monitoring,evaluation,and maintenance of engineering structure safety.By studying the principle,application scenarios,and advantages of intelligent technology in structural safety evaluation,this paper summarizes how intelligent technology can improve engineering management efficiency and reduce safety risks,and puts forward the trend and challenge of future development.
基金supported by the Zhejiang Provincial Natural Science Foundation of China under Grant No.LTGG23E080001Zhejiang Engineering Research Center of Intelligent Urban Infrastructure under Grant No.IUI2022-ZD-01.
文摘Kinked rebar is a special type of steel material,which is installed in beam column nodes and frame beams.It effectively enhances the blast resilience,seismic collapse resistance,and progressive collapse resistance of reinforced concrete(RC)structures without imposing substantial cost burdens,thereby emerging as a focal point of recent research endeavors.On the basis of explaining the working principle of kinked rebars,this paper reviews the research status of kinked rebars at home and abroad from three core domains:the tensile mechanical properties of kinked rebars,beam column nodes with kinked rebars,and concrete frame structures with kinked rebars.The analysis underscores that the straightening process of kinked rebars does not compromise their ultimate strength but significantly bolsters structural ductility and enhances energy dissipation capabilities.In beam-column joints,the incorporation of kinked rebars facilitates the seamless transfer of plastic hinges,adhering to the design principle of“strong columns and weak beams.”In addition,kinked rebars can greatly improve the resistance of the beam;The seismic resistance,internal explosion resistance,and progressive collapse resistance of reinforced concrete frame structures with kinked rebar have significantly improved.Beyond its primary application,the principle of kinked rebar was extended to other applications of kinked materials such as corrugated steel plates and origami structures,and the stress characteristics of related components and structures were studied.Intriguingly,this paper also proposes the application of kinked rebars in bridge engineering,aiming to address the challenges of localized damage concentration and excessive residual displacement in RC bridge piers.The introduction of kinked rebars in piers is envisioned to mitigate these issues,with the paper outlining its advantages and feasibility,thereby offering valuable insights for future research on kinked reinforcement and seismic design strategies for bridges.
文摘In civil engineering, the nonlinear dynamic instability of structures occurs at a bifurcation point or a limit point. The instability at a bifurcation point can be analyzed with the theory of nonlinear dynamics, and that at a limit point can be discussed with the theory of elastoplasticity. In this paper, the nonlinear dynamic instability of structures was treated with mathematical and mechanical theories. The research methods for the problems of structural nonlinear dynamic stability were discussed first, and then the criterion of stability or instability of structures, the method to obtain the bifurcation point and the limit point, and the formulae of the directions of the branch solutions at a bifurcation point were elucidated. These methods can be applied to the problems of nonlinear dynamic instability of structures such as reticulated shells, space grid structures, and so on. Key words nonlinear dynamic instability - engineering structures - non-stationary nonlinear system - bifurcation point - instability at a bifurcation point - limit point MSC 2000 74K25 Project supported by the Science Foundation of Shanghai Municipal Commission of Education (Grant No. 02AK04), the Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No. 02ZA14034)
文摘Topometric auscultation is used to monitor the durability of structures, measure deformations linked to the structure of a structure or to the movement of the ground over a part of the globe, set up warning systems, etc. It first appeared as a visual method and rapidly evolved through the various techniques used. Some of these techniques using topography are used in several fields (civil engineering, geodesy, topography, mechanics, nuclear engineering, hydraulics, physics, etc.). These topometric techniques have undergone major changes as a result of technological advances, growing needs in the monitoring of movements or deformations, increased requirements and new challenges. The methodology adopted depends on the measuring instrument used, the parameters to be estimated and access to the area to be measured. There are two types of methods: destructive and non-destructive. In addition to the visual method, they can also be classified as mechanical, physico-chemical, dynamometric, electrophysical and geometric. The estimated parameter varies according to the methodology adopted. It can be defined by coordinates, distances, potential, electrical resistance, etc.
基金supported by the National Natural Science Foundation of China(Nos.22472071,21832005,22072168,22002175)the Natural Science Foundation of Gansu Province(No.21JR7RA440)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21061011)。
文摘Constrained by severe bulk charge recombination,the actual photocurrent density of tantalum nitride(Ta_(3)N_(5))photoanode is much lower than the theoretical maximum value.Herein,we report the doping of phosphorus,a non-metallic element distinct from oxygen,into Ta_(3)N_(5),resulting in a photocurrent density 9 times higher than that of pristine Ta_(3)N_(5).Systematic characterization reveals that the phosphorus doping simultaneously enhances the bulk charge separation efficiency and surface charge injection efficiency of Ta_(3)N_(5),and induces favorable band energy restructuring.Specifically,a type-II homojunction formed between phosphorus-doped near-surface region and bulk Ta_(3)N_(5) effectively promotes the separation and transfer of photogenerated holes and electrons.Further modification with a Ni Fe-based cocatalyst enables the optimized photoanode to deliver a photocurrent density of 10 mA/cm^(2) at 1.23 V versus the reversible hydrogen electrode(RHE)and an applied bias photo-to-current efficiency of 1.78%at 0.95 V versus RHE.Our work provides a foundation for the development of a broader range of non-metal doped semiconductors.
基金the financial support from International Society of Engineering Science and Technology(ISEST)UK。
文摘The conversion of carbon dioxide(CO_(2))into hydrocarbons through electrochemical CO_(2)reduction reaction(eCO_(2)RR)shows a promising method to reduce CO_(2)levels and decrease reliance on fossil fuels in the years to come.Copper-based electrocatalysts exhibit a pronounced inclination for C-C coupling,drawing considerable interest as a favored metal catalyst for generating C_(2+)products through CO_(2)RR.However,CO_(2)RR still has some obstacles including product selectivity,higher overpotential,low Faradic efficiency(FE),stability,and current density(CD).Therefore,advancement in this field enables us to comprehend the complex multi-proton electron transfer during C-C coupling and engineering strategies to improve FE and CD.Herein,this review presents some key features of Cu-based catalysts as an electrocatalyst for C_(2) product formation while addressing the industrial challenges that hinder commercialization of CO_(2)RR.In addition,recent strategies on Cu-based catalysts,synthesis strategies,advanced characterizations,and mechanistic investigations via theoretical simulations have been presented.Furthermore,recent approaches towards the composition,oxidation states,and active facets have been presented.Thus,the most favorable mechanism and possible pathways to synthesize C_(2+)products have been explained using theoretical calculations.
基金supported by the Science and Technology Plan of Fujian Provincial,China(2022G02020 and 2022H6002)the Collaborative Innovation Platform Project for Advanced Electrochemical Energy Storage Technology,Fuxiaquan National Independent Innovation Demonstration Zone,China(3502ZCQXT2022001)+1 种基金the Significant Science and Technology Project of Xiamen(the Future Industrial Area),China(3502Z20231058)the Scientific Research Startup Funding for Special Professor of Minjiang Scholars。
文摘Silicon(Si)-based anodes have emerged as promising candidates for the next-generation lithium-ion batteries(LIBs)due to their high theoretical capacity(4200 mAh g^(-1)).However,their further application is hindered by critical challenges,including severe volume expansion(~300%),formation of unstable solid electrolyte interphase(SEI),and inherently low conductivity.While extensive research has sought to alleviate the substantial internal stress caused by volume expansion through the rational design of Si-based anode structures,the underlying mechanisms that govern these improvements remain insufficiently understood,leaving significant gaps in mechanical and interface electrical failure.To build a comprehensive understanding relationship between structural design and performance enhancement of Si-based anodes,this review first analyzes the characteristics of various Sibased anode structures and their associated internal stresses.Subsequently,it summarizes effective strategies to optimize the performance of Si-based anodes,including doping design,novel electrolyte design,and fu nctional binder design.Additionally,we assess emerging technologies with high commercial potential for structural design and interfacial modification,such as porous carbon carriers,chemical vapor deposition(CVD),spray granulation,and pre-lithiation.Finally,this work provides perspectives on the structural design of Si-based anodes.Overall,this review systematically summarizes modification strategies for Si-based anodes through structural regulation and interface engineering,thereby providing a foundation for advanced structural and interfacial design.
基金supported by the National Natural Science Foundation of China Major Research Plan(Grant No.90715032)
文摘The NSFC Major Research Plan aims to conduct researches at the international research frontiers on modeling of strong earthquake ground motions and strong wind or typhoon fields,and investigating the damage and failure evolution process of the major engineering structures under dynamic actions,focusing on the following two key scientific problems:(1)characteristics and laws of strong earthquake ground motions and strong wind or typhoon fields,and(2)process and mechanism of dynamic disaster evolution of the major engineering structures.For these goals,the research work is targeted at(1)modeling and predicting of strong earthquake ground motion and strong wind or typhoon fields,(2)identifying critical parameters influencing the dynamic disaster evolution of the major engineering structures,(3)analyzing the whole dynamic disaster evolution process of the major engineering structures,and(4)integration and verification of simulation systems for dynamic disaster evolution of the major engineering structures.
基金This work was supported by the National Natural Sci- ence Foundation of China （No.11034006, No.21273208, and No.21473168）, the Anhui Provincial Natural Sci- ence Foundation （No.1408085QB26）, the hmdamental Research Funds for the Central Universities, the China Postdoctoral Science Foundation （No.2012M511409）, and the Supercomputing Center of Chinese Academy of Sciences, Shanghai and USTC Supercomputer Cen- ters.
文摘Doping with various impurities is an effective approach to improve the photoelectrochemical properties of TiO2. Here, we explore the effect of oxygen vacancy on geometric and elec- tronic properties of compensated （i.e. V-N and Cr-C） and non-compensated （i.e. V-C and Cr-N） codoped anatase TiO2 by performing extensive density functional theory calculations. Theoretical results show that oxygen vacancy prefers to the neighboring site of metal dopant （i.e. V or Cr atom）. After introduction of oxygen vacancy, the unoccupied impurity bands located within band gap of these codoped TiO2 will be filled with electrons, and the posi- tion of conduction band offset does not change obviously, which result in the reduction of photoinduced carrier recombination and the good performance for hydrogen production via water splitting. Moreover, we find that oxygen vacancy is easily introduced in V-N codoped TiO2 under O-poor condition. These theoretical insights are helpful for designing codoped TiO2 with high photoelectrochemical performance.
基金support from Australian Research Council (ARC, FT150100450, IH150100006 and CE170100039)support from the MCATM and the FLEET+1 种基金the support from Shenzhen Nanshan District Pilotage Team Program (LHTD20170006)support from Guangzhou Science and Technology Program (Grant No. 201804010322)
文摘Metal halide perovskite nanostructures have emerged as low-dimensional semiconductors of great significance in many fields such as photovoltaics,photonics,and optoelectronics.Extensive efforts on the controlled synthesis of perovskite nanostructures have been made towards potential device applications.The engineering of their band structures holds great promise in the rational tuning of the electronic and optical properties of perovskite nanostructures,which is one of the keys to achieving efficient and multifunctional optoelectronic devices.In this article,we summarize recent advances in band structure engineering of perovskite nanostructures.A survey of bandgap engineering of nanostructured perovskites is firstly presented from the aspects of dimensionality tailoring,compositional substitution,phase segregation and transition,as well as strain and pressure stimuli.The strategies of electronic doping are then reviewed,including defect-induced self-doping,inorganic or organic molecules-based chemical doping,and modification by metal ions or nanostructures.Based on the bandgap engineering and electronic doping,discussions on engineering energy band alignments in perovskite nanostructures are provided for building high-performance perovskite p-n junctions and heterostructures.At last,we provide our perspectives in engineering band structures of perovskite nanostructures towards future low-energy optoelectronics technologies.
基金financially supported by the National Natural Science Foundation of China(Nos.52075351 and 51604177)the National Key Research and Development Program of China(No.2019YFA0705701)+4 种基金the Major S&T Infrastructure Construction Project of Sichuan Province(No.2020-510000-73-01-441847)the International S&T Innovation Cooperation Program of Sichuan Province(No.2020YFH0039)Chengdu International S&T Cooperation Funded Project(Nos.2020-GH02-00006-HZ and 2022-GH02-00027-HZ)the"1000 Talents Plan"of Sichuan Provincethe Talent Introduction Program of Sichuan University(No.YJ201410)。
文摘Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its commercialization.These challenges include lithium dendrite growth in the anode side,volume change of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode side.Since the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it has also been widely discussed in addressing the abovementioned issues.In this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and summarized.Crucially,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in detail.Finally,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.
基金This work was supported by the National Natural Science Foundation of China(52372289,52102368,52072192 and 51977009)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905).
文摘The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.
基金support from the National Natural Science Foundation of China(Grant No.11725418)the National Key Research and Development Program of China(Grant No.2016YFA0301004)+3 种基金Science Challenge Project,China(Grant No.TZ2016004)Beijing Advanced Innovation Center for Future Chip(ICFC)Tsinghua University Initiative Scientific Research Programfunded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)–TRR 173–268565370(projects A02)。
文摘Artificially constructed van der Waals heterostructures(vdWHs)provide an ideal platform for realizing emerging quantum phenomena in condensed matter physics.Two methods for building vdWHs have been developed:stacking two-dimensional(2D)materials into a bilayer structure with different lattice constants,or with different orientations.The interlayer coupling stemming from commensurate or incommensurate superlattice pattern plays an important role in vdWHs for modulating the band structures and generating new electronic states.In this article,we review a series of novel quantum states discovered in two model vdWH systems—graphene/hexagonal boron nitride(hBN)hetero-bilayer and twisted bilayer graphene(tBLG),and discuss how the electronic structures are modified by such stacking and twisting.We also provide perspectives for future studies on hetero-bilayer materials,from which an expansion of 2D material phase library is expected.
文摘With the continuous development of urbanization construction, rail transit has received more and more attention. For the current subway station, the main structure of open-cut subway station plays an important role in it. Therefore, the leakage problem with high frequency should be analyzed in time and dealt with reasonably. In this paper, the construction technology of leakage treatment for the main structure of open-cut subway station is analyzed for reference.
文摘Architectural structure engineering occupies a major position in architectural engineering and has a direct impact on the design quality of the whole building. As far as architectural structure design is concerned, safety and durability have received more and more attention, which are also the two major focuses of current architectural structure engineering design. However, there are still some problems in carrying out these two tasks, which greatly affect the final construction quality. This paper studies the durability and safety of building structure engineering, hoping to effectively improve the overall design quality of building structure and meet the living needs.
文摘The construction project in the actual construction process, in order to comprehensively ensure the construction quality, we should strengthen the importance of the main design of the building, and through the application of standardized construction technology, reasonable control of the construction progress and quality, to ensure the smooth progress of the follow-up work. Based on this, this paper mainly around the importance of the construction of the main structure of the building to launch an analysis, elaborated the technical application countermeasures.
文摘It is not difficult to find out that cracks in concrete structural engineering are ubiquitous. Because the damage of the structure often begins with cracks, it brings harm and risk to social production and life. Especially with the rapid development of my country's capital construction in recent decades, it is very necessary to understand and solve the ancient and novel problem of cracks in concrete structures. With the exploration and research of long-term engineering practice, with the continuous development of technology and productivity, people have realized that the generation of harmful cracks can be controlled through effective technical means. That is to say, through the organic combination of design and construction, the influence of cracks can be prevented from being harmful.
基金supported by the National Natural Science Foundation of China(No.52272242)the Provisional Key Research and Development Program of Henan Province,China(No.231111240600)+1 种基金the Natural Science Foundation of Henan Province,China(No.242300421428)the Start-up Funding for Scientific Research of Zhengzhou University,China(No.32310221).
文摘Supercapacitors(SCs)stand out among various energy storage devices owing to their high power density and long-term cyc-ling stability.As new two-dimensional material,MXenes have become a research hotspot in recent years owing to their unique structure and rich surface functional groups.Compared with other materials,MXenes are more promising for SCs owing to their tunable precurs-ors,structural stability,and excellent electrical conductivity.However,the rate performance and electrochemical reaction activity of MXene materials are poor,and stacking severely limits their application.Therefore,various modification strategies are employed to im-prove the electrochemical performance of MXene materials.As the modification strategy of MXene electrode materials often involves in-creasing the number of ion transport channels to expose more active sites,the packing density is also affected to different degrees.There-fore,achieving a balance between high volumetric capacitance and rapid ion transport has become a key issue for the application of MXene-based SCs in wearable devices and microdevices.In this paper,the latest progress in the preparation methods and modification strategies of MXenes in recent years is reviewed with the aim of achieving both high volumetric capacitance and high ion transport for ex-panding the application of MXene-based SCs in microdevices and wearable devices.
基金supported by the National Natural Science Foundation of China(No.52301260)the National Science Foundation of Jiangsu Province(No.BK20230712)China Postdoctoral Science Foundation(No.2022M711686).
文摘The two-dimensional MoSe_(2)possesses a large interlayer spacing(0.65 nm)and a narrow bandgap(1.1 eV),showing potential in sodium-ion storage.However,it faces slow kinetics and volume stress during Na^(+)(de)intercalation process,thereby affecting the cycling stability and lifespan of sodium-ion batteries(SIBs).In this work,a novel approach involving anionic doping and structural design has been proposed,wherein a two-step in-situ selenization and surface thermal annealing doping process is applied to fabricate a novel configuration material of fluorine-doped MoSe_(2)@nitrogen-doped carbon nanosheets(F-MoSe_(2)@FNC).The obtained F-MoSe_(2)@FNC,benefiting from the dual advantages of structure and F-doping,synergistically promotes and accelerates the stable(de)intercalation of Na^(+).Henceforth,F-MoSe_(2)@FNC demonstrates notable characteristics in terms of reversible specific capacity,boasting a high initial coulombic efficiency of 76.97%,alongside remarkable rate capabilities and cyclic stability.The constructed F-MoSe_(2)@FNC anode-based half cell manifests exceptional longevity,enduring up to 2550 cycles at 10 A·g^(-1)with a specific capacity of 322.04 mAh·g^(-1).Its electrochemical performance surpasses that of MoSe_(2)@NC and Pure MoSe_(2),underscoring the significance of the proposed synergistic modulation.Through comprehensive kinetic analyses,encompassing in-situ electrochemical impedance spectroscopy(EIS),it is elucidated that the F-MoSe_(2)@FNC electrode showcases elevated pseudo-capacitance and rapid diffusion attributes during charge and discharge processes.Furthermore,the assembled full-cell(F-MoSe_(2)@FNC//Na_(3)V_(2)(PO_(4))_(3))attains a notable energy density of 166.94 Wh·kg^(-1).This design provides insights for the optimization of MoSe_(2)electrodes and their applications in SIBs.
