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Independent dislocation space model for synchronous improvement of strength and plasticity in fcc metals
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作者 Rui Liu Keqiang Li +3 位作者 Zhenjun Zhang Zhan Qu Peng Zhang Zhefeng Zhang 《Journal of Materials Science & Technology》 2025年第21期239-244,共6页
Strength and plasticity of metallic structural materials are the fundamental indicators of the service reliability[1].However,as is well known,a general trade-offrelationship exists between strength and plasticity of ... Strength and plasticity of metallic structural materials are the fundamental indicators of the service reliability[1].However,as is well known,a general trade-offrelationship exists between strength and plasticity of metallic materials,making it difficult to improve both of them synchronously[2].At present,only few of the successful cases[3-8],achieved via nano-particles[7],heterogeneous microstructures[8],etc.are mostly limited to some specific materials or processes. 展开更多
关键词 metallic materialsmaking nanoparticles STRENGTH heterogeneous microstructures trade off strength plasticity PLASTICITY metallic structural materials
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Failure Mechanisms and Structural Optimization of Shredder Hammer for Metal Scraps 被引量:1
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作者 ZHOU Xianyan HU Zhili +2 位作者 TAO Yijun QIN Xunpeng HUA Lin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第4期792-801,共10页
Recycling retired cars can relieve the environmental pollution and resource waste efficiently.However,a few publications can be found on the failure mechanisms and optimization method of recycling equipment,shredders.... Recycling retired cars can relieve the environmental pollution and resource waste efficiently.However,a few publications can be found on the failure mechanisms and optimization method of recycling equipment,shredders.Thus,the failure mechanisms and structural optimization of shredder hammers for retired cars are studied aiming improving shredding efficiency and reducing cost.Failure types of shredder hammer are studied theoretically,and it is found that wear failure and fatigue failure are the two main failure types of shredder hammer.The shredding process of metal scraps is analyzed by finite element method,and it can be divided into four stages based on the stress states:initial stage,collision stage,grinding stage and separation stage.It is proved that the shredding efficiency can be improved by increasing cutouts on the hammer head.Finally,it is determined that the hammer with two cutouts is the optimal structure for metal scraps,which can improve the shredding efficiency by 20% and lengthen the hammer life by 15%.This study provides scientific basis for the industry application and theoretical foundation for further research. 展开更多
关键词 Metal scraps recycling impacts grinding structural optimization
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In situ electronic structural study of VO_2 thin film across the metal–insulator transition
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作者 伊明江.买买提 阿布都艾则孜.阿布来提 +3 位作者 吴蕊 王嘉鸥 钱海杰 奎热西.依布拉欣 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第12期410-415,共6页
The in situ valence band photoemission spectrum (PES) and X-ray absorption spectrum (XAS) at V LⅡ-LⅢ edges of the VO2 thin film, which is prepared by pulsed laser deposition, are measured across the metal–insul... The in situ valence band photoemission spectrum (PES) and X-ray absorption spectrum (XAS) at V LⅡ-LⅢ edges of the VO2 thin film, which is prepared by pulsed laser deposition, are measured across the metal–insulator transition (MIT) temperature (TMIT=67 ℃). The spectra show evidence for changes in the electronic structure depending on temperature. Across the TMIT, pure V 3d characteristic d‖ and O 2p-V 3d hybridization characteristic πpd, σpd bands vary in binding energy position and density of state distributions. The XAS reveals a temperature-dependent reversible energy shift at the V LⅢ-edge. The PES and XAS results imply a synergetic energy position shift of occupied valence bands and unoccupied conduction band states across the phase transition. A joint inspection of the PES and XAS results shows that the MIT is not a one-step process, instead it is a process in which a semiconductor phase appears as an intermediate state. The final metallic phase from insulating state is reached through insulator–semiconductor, semiconductor–metal processes, and vice versa. The conventional MIT at around the TMIT=67 ℃ is actually a semiconductor–insulator transformation point. 展开更多
关键词 vanadium dioxide metal–insulator transition electronic structure photoemission spectroscopy
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First Principles Study of Structural Stability and Magnetic Property of Non-equilibrium Co–Mo Alloys
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作者 Shunning Li Baixin Liu Jianbo Liu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2014年第6期1057-1062,共6页
First principles calculations are carried out to investigate the structural stability of several non-equilibrium intermetallic phases in the cobalt(Co)–Mo system using spin polarized projected augmented-wave potent... First principles calculations are carried out to investigate the structural stability of several non-equilibrium intermetallic phases in the cobalt(Co)–Mo system using spin polarized projected augmented-wave potentials. It is revealed that the Co3Mo, CoMo, and CoMo3 alloys are energetically favored to be in D019, B11, and A15 structures, respectively,and that the magnetic moments of Co atoms would decrease rapidly with an increasing percentage of Mo content and would most probably disappear when the content of Mo is no less than 50 at%. Generally, the calculated results in the present work match well with the available experimental observations. 展开更多
关键词 First principles calculation Transition metals Cobalt Magnetic property Electronic structure
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Structural elucidation, theoretical investigation using DFT calculations,thermal and dielectric analyses of new zinc(Ⅱ) based inorganic–organic hybrid
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作者 Nejla Chihaoui Besma Hamdi Ridha Zouari 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第3期642-650,共9页
A novel interesting d^(10) metal hybrid, [1,2-C_6H_(10)(NH_3)_2]ZnCl_4; 1,2-diammoniumcyclohexane tetrachlorozincate(II) was grown, structurally characterized and their vibrational as well as thermal and diele... A novel interesting d^(10) metal hybrid, [1,2-C_6H_(10)(NH_3)_2]ZnCl_4; 1,2-diammoniumcyclohexane tetrachlorozincate(II) was grown, structurally characterized and their vibrational as well as thermal and dielectric proprieties were studied. A preliminary single crystal X-ray diffraction structural analysis has revealed that the latter crystallizes in the monoclinic system(space group C2/c). Its unit cell dimensions are a = 32.394(9) ?, b = 12.217(4) ?, c = 10.175(3) ?, β = 97.852(13)° with Z = 12 and the refinement converged to R = 0.034 and ωR = 0.065. Hirshfeld surface analyses, especially d_(norm)surface and fingerprint plots were used for decoding intermolecular interactions in the crystal network. The optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the present compound were theoretically examined by the DFT/B3 LYP method with the Lan L2 DZ basis set. The thermal and dielectric analyses suggested the presence of ferroelectric phase transition at 314 K. 展开更多
关键词 d^(10) metal hybrid Chlorozincate(Ⅱ) Crystal structure DFT/B3LYP/Lan L2DZ FT-IR Raman scattering Dielectric analyses
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YOLO-L:A High-Precision Model for Defect Detection in Lattice Structures
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作者 Baosu Guo Hang Li +5 位作者 Shichen Ding Longhua Xu Meina Qu Dijia Zhang Yintang Wen Chuanzhen Huang 《Additive Manufacturing Frontiers》 2025年第2期185-193,共9页
High-performance lattice structures produced through powder bed fusion-laser beam exhibit high specific strength and energy absorption capabilities.However,a significant deviation exists between the mechanical propert... High-performance lattice structures produced through powder bed fusion-laser beam exhibit high specific strength and energy absorption capabilities.However,a significant deviation exists between the mechanical properties,service life of lattice structures,and design expectations.This deviation arises from the intense interaction between the laser and powder,which leads to the formation of numerous defects within the lattice structure.To address these issues,this paper proposes a high-performance defect detection model for metal lattice structures based on YOLOv4,called YOLO-Lattice(YOLO-L).The main objectives of this paper are as follows:(1)utilize computed tomography to construct datasets of the diamond lattice and body-centered cubic lattice structures;(2)in the backbone network of YOLOv4,employ deformable convolution to enhance the feature extraction capability of the model for small-scale defects;(3)adopt a dual-attention mechanism to suppress invalid feature information and amplify the distinction between defect and background regions;and(4)implement a channel pruning strategy to eliminate channels carrying less feature information,thereby improving the inference speed of the model.The experimental results on the diamond lattice structure dataset demonstrate that the mean average precision of the YOLO-L model increased from 96.98% to 98.8%(with an intersection over union of 0.5),and the inference speed decreased from 51.3 ms to 32.5 ms when compared to YOLOv4.Thus,the YOLO-L model can be effectively used to detect defects in metal lattice structures. 展开更多
关键词 Defect detecting Metal lattice structure YOLO Additive manufacturing
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A review of the experimental and numerical studies on the compression behavior of the additively produced metallic lattice structures at high and low strain rates
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作者 Muhammad Arslan Bin Riaz Mustafa Guden 《Defence Technology(防务技术)》 2025年第7期1-49,共49页
Recent advances in additive manufacturing have enabled the construction of metallic lattice structures with tailored mechanical and functional properties.One potential application of metallic lattice struc-tures is in... Recent advances in additive manufacturing have enabled the construction of metallic lattice structures with tailored mechanical and functional properties.One potential application of metallic lattice struc-tures is in the impact load mitigation where an external kinetic energy is absorbed by the deformation/crushing of lattice cells.This has motivated a growing number of experimental and numerical studies,recently,on the crushing behavior of additively produced lattice structures.The present study overviews the dynamic and quasi-static crushing behavior of additively produced Ti64,316L,and AlSiMg alloy lattice structures.The first part of the study summarizes the main features of two most commonly used additive processing techniques for lattice structures,namely selective-laser-melt(SLM)and electro-beam-melt(EBM),along with a description of commonly observed process induced defects.In the second part,the deformation and strain rate sensitivities of the selected alloy lattices are outlined together with the most widely used dynamic test methods,followed by a part on the observed micro-structures of the SLM and EBM-processed Ti64,316L and AlSiMg alloys.Finally,the experimental and numerical studies on the quasi-static and dynamic compression behavior of the additively processed Ti64,316L,and AlSiMg alloy lattices are reviewed.The results of the experimental and numerical studies of the dynamic properties of various types of lattices,including graded,non-uniform strut size,hollow,non-uniform cell size,and bio-inspired,were tabulated together with the used dynamic testing methods.The dynamic tests have been noted to be mostly conducted in compression Split Hopkinson Pressure Bar(SHPB)or Taylor-and direct-impact tests using the SHPB set-up,in all of which relatively small-size test specimens were tested.The test specimen size effect on the compression behavior of the lattices was further emphasized.It has also been shown that the lattices of Ti64 and AlSiMg alloys are relatively brittle as compared with the lattices of 316L alloy.Finally,the challenges associated with modelling lattice structures were explained and the micro tension tests and multi-scale modeling techniques combining microstructural characteristics with macroscopic lattice dynamics were recommended to improve the accuracy of the numerical simulations of the dynamic compression deformations of metallic lattice structures. 展开更多
关键词 Metallic lattice structures Additive manufacturing Strain rate sensitivity MICROSTRUCTURE Dynamic compression High strain rate loading MODELLING
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Kelvin lattice structures fabricated by laser powder bed fusion:Design,preparation,and mechanical performance
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作者 Yan-peng Wei Huai-qian Li +3 位作者 Ying-chun Ma Zhi-quan Miao Bo Yu Feng Lin 《China Foundry》 2025年第2期117-127,共11页
Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have ga... Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have garnered increasing research interest.However,most metallic lattice structures generally exhibit anisotropic characteristics,which limits their application ranges.Additionally,a limited number of studies have successfully developed precise mechanical models,which have undergone experimental validation,for the purpose of describing the mechanical response exhibited by additively manufactured metallic lattice structures.In this study,Kelvin lattice structures with varying porosities were systematically designed and fabricated using laser powder bed fusion(LPBF)technology.By integrating finite element simulations with experimental characterization,an enhanced mechanical model was developed through a modification of the Gibson-Ashby model,providing an accurate quantitative description of the relationship between porosity and mechanical properties.The results show that the revised mechanical model can accurately describe the relationship between the geometric parameters and properties of metallic lattice structures.Specifically,the designed Kelvin lattice structures exhibit a smooth stress-strain curve with an obvious yield platform,demonstrating isotropic mechanical properties in all the three spatial directions.This enhances their suitability for complex loading conditions.Meanwhile,the microstructure and manufacturing accuracy of the Kelvin lattice structures were observed and analyzed by micro computed tomography.The results show that the fabricated metallic lattice structures achieved precise dimensional control and optimal densification.This study presents the complete process involved in modeling the Kelvin structure,including its conceptualization,manufacturing,implementation,and ultimately,disposal. 展开更多
关键词 Kelvin structure metallic lattice structures laser powder bed fusion mechanical model isotropic mechanical properties
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Synergetic Enhancement of Hardness and Toughness in New Superconductors Ti_(2)Co and Ti_(4)Co_(2)O
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作者 Lifen Shi Keyuan Ma +12 位作者 Jingyu Hou Pan Ying Ningning Wang Xiaojun Xiang Pengtao Yang Xiaohui Yu Huiyang Gou Jianping Sun Yoshiya Uwatoko Fabian O.von Rohr Xiangfeng Zhou Bosen Wang Jinguang Cheng 《Chinese Physics Letters》 2025年第6期170-177,共8页
Compared to traditional superhard materials with high electron density and short,strong covalent bonds,alloy materials mainly composed of metallic bonding structures typically have great toughness and lower hardness.B... Compared to traditional superhard materials with high electron density and short,strong covalent bonds,alloy materials mainly composed of metallic bonding structures typically have great toughness and lower hardness.Breaking through the limits of alloy materials is a preface and long-term topic,which is of great significance and value for improving the comprehensive mechanical properties of alloy materials.Here,we report on the discovery of a cubic alloy semiconducting material Ti_(2)Co with a large Vickers of hardness K_(v)^(exp)∼6.7GPa and low fracture toughness of K_(IC)^(exp)∼1.51MPa·m^(1/2).Unexpectedly,the K_(v)^(exp)∼6.7GPa is nearly triple of the K_(v)^(cal)∼2.66GPa predicted by density functional theory(DFT)calculations and theK_(IC)^(exp)∼1.51MPa·m^(1/2)is about one or two orders of magnitude smaller than that of ordinary titanium alloy materials(K_(IC)^(exp)∼30-120MPa·m^(1/2)).These specifications place Ti_(2)Co far from the phase space of the known alloy materials.Upon incorporation of oxygen into structural void positions,both values were simultaneously improved for Ti_(4)Co_(2)O to∼9.7GPa and∼2.19MPa·m^(1/2),respectively.Further DFT calculations on the electron localization function of Ti_(4)Co_(2)X(X=B,C,N,O)vs.the interstitial elements indicate that these simultaneous improvements originate from the coexistence of Ti-Co metallic bonds,the emergence of newly oriented Ti-X covalent bonds,and the increase of electron concentration.Moreover,the large difference between K_(v)^(exp)and K_(v)^(cal)of Ti_(2)Co suggests underlying mechanism concerning the absence of the O(16d)or Ti_(2)-O bonds in the O-(Ti_(2))_(6) octahedron.This discovery proposes a new pathway to simultaneously improve the comprehensive mechanical performances and illuminates the path of exploring superconducting materials with excellent mechanical performances. 展开更多
关键词 limits metallic bonding structures superhard materials HARDNESS SUPERCONDUCTORS alloy materials improving comprehensive mechanical properties cubic alloy semiconducting material
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Design for a Crane Metallic Structure Based on Imperialist Competitive Algorithm and Inverse Reliability Strategy 被引量:8
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作者 Xiao-Ning Fan Bo Zhi 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第4期900-912,共13页
Uncertainties in parameters such as materials, loading, and geometry are inevitable in designing metallic structures for cranes. When considering these uncertainty factors, reliability-based design optimization (RBDO... Uncertainties in parameters such as materials, loading, and geometry are inevitable in designing metallic structures for cranes. When considering these uncertainty factors, reliability-based design optimization (RBDO) offers a more reasonable design approach. However, existing RBDO methods for crane metallic structures are prone to low convergence speed and high computational cost. A unilevel RBDO method, combining a discrete imperialist competitive algorithm with an inverse reliabil- ity strategy based on the performance measure approach, is developed. Application of the imperialist competitive algorithm at the optimization level significantly improves the convergence speed of this RBDO method. At the reli- ability analysis level, the inverse reliability strategy is used to determine the feasibility of each probabilistic constraint at each design point by calculating its a-percentile per- formance, thereby avoiding convergence failure, calcula- tion error, and disproportionate computational effort encountered using conventional moment and simulation methods. Application of the RBDO method to an actual crane structure shows that the developed RBDO realizes a design with the best tradeoff between economy and safety together with about one-third of the convergence speed and the computational cost of the existing method. This paper provides a scientific and effective design approach for the design of metallic structures of cranes. 展开更多
关键词 Crane metallic structure Reliability-baseddesign optimization Imperialist competitive algorithmPerformance measure approach Inverse reliabilitystrategy
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Intelligent Optimization Methods for the Design of an Overhead Travelling Crane 被引量:6
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作者 QU Xiaogang XU Gening +1 位作者 FAN Xiaoning BI Xiaoheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第1期187-196,共10页
In design optimization of crane metal structures, present approaches are based on simple models and mixed variables, which are difficult to use in practice and usually lead to failure of optimized results for rounding... In design optimization of crane metal structures, present approaches are based on simple models and mixed variables, which are difficult to use in practice and usually lead to failure of optimized results for rounding variables. Crane metal structure optimal design(CMSOD) belongs to a constrained nonlinear optimization problem with discrete variables. A novel algorithm combining ant colony algorithm with a mutation-based local search(ACAM) is developed and used for a real CMSOD for the first time. In the algorithm model, the encoded mode of continuous array elements is introduced. This not only avoids the need to round optimization design variables during mixed variable optimization, but also facilitates the construction of heuristic information, and the storage and update of the ant colony pheromone. Together with the proposed ACAM, a genetic algorithm(GA) and particle swarm optimization(PSO) are used to optimize the metal structure of a crane. The optimization results show that the convergence speed of ACAM is approximately 20% of that of the GA and around 11% of that of the PSO. The objective function value given by ACAM is 22.23% less than the practical design value, a reduction of 16.42% over the GA and 3.27% over the PSO. The developed ACAM is an effective intelligent method for CMSOD and superior to other methods. 展开更多
关键词 crane metal structure design optimization continuous array element encoded model ant colony optimization particle swarm optimization genetic algorithm
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Recent Developments of Transition Metal Compounds-Carbon Hybrid Electrodes for High Energy/Power Supercapacitors 被引量:8
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作者 Kang Ren Zheng Liu +1 位作者 Tong Wei Zhuangjun Fan 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第8期231-262,共32页
Due to their rapid power delivery,fast charging,and long cycle life,supercapacitors have become an important energy storage technology recently.However,to meet the continuously increasing demands in the fields of port... Due to their rapid power delivery,fast charging,and long cycle life,supercapacitors have become an important energy storage technology recently.However,to meet the continuously increasing demands in the fields of portable electronics,transportation,and future robotic technologies,supercapacitors with higher energy densities without sacrificing high power densities and cycle stabilities are still challenged.Transition metal compounds(TMCs)possessing high theoretical capacitance are always used as electrode materials to improve the energy densities of supercapacitors.However,the power densities and cycle lives of such TMCs-based electrodes are still inferior due to their low intrinsic conductivity and large volume expansion during the charge/discharge process,which greatly impede their large-scale applications.Most recently,the ideal integrating of TMCs and conductive carbon skeletons is considered as an effective solution to solve the above challenges.Herein,we summarize the recent developments of TMCs/carbon hybrid electrodes which exhibit both high energy/power densities from the aspects of structural design strategies,including conductive carbon skeleton,interface engineering,and electronic structure.Furthermore,the remaining challenges and future perspectives are also highlighted so as to provide strategies for the high energy/power TMCs/carbon-based supercapacitors. 展开更多
关键词 TMCs/carbon hybrid SUPERCAPACITORS High power density Carbon skeleton Interfacial engineering Transition metal electronic structure
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Formation, Structure and Properties of Bulk Metallic Glasses 被引量:4
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作者 Y. Li(Department of Materials Science, Faculty of Science, National University of Singapore, Lower Kent Ridge Road,Singapore 119260 E-mail:masliy@nus.edu.sg) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第2期97-110,共14页
Bulk metallic glasses with up to 72 mm critical section thickness have been obtained by conventional casting techniques and the properties of these materials, particularly the mechanical and magnetic properties have b... Bulk metallic glasses with up to 72 mm critical section thickness have been obtained by conventional casting techniques and the properties of these materials, particularly the mechanical and magnetic properties have been studied. These materials have been demonstrated to have novel properties which are fundamentally different from their crystalline counterparts. The recent status of research and development in formation, structure and properties of bulk metallic glasses is reviewed. The techniques to produce such bulk glasses are summarized and the glass forming ability and the critical cooling rate of these materials are discussed. Further consideration of the development and application of this new class of materiaIs will be proposed. 展开更多
关键词 NI ZR Structure and Properties of Bulk Metallic Glasses FORMATION OK Cu FIGURE
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Fatigue Life Evaluation Method for Foundry Crane Metal Structure Considering Load Dynamic Response and Crack Closure Effect 被引量:3
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作者 Qing Dong Bin He Gening Xu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第2期525-553,共29页
To compensate for the shortcomings of quasi-static law in anti-fatigue analysis of foundry crane metal structures,the fatigue life evaluation method of foundry crane metal structure considering load dynamic response a... To compensate for the shortcomings of quasi-static law in anti-fatigue analysis of foundry crane metal structures,the fatigue life evaluation method of foundry crane metal structure considering load dynamic response and crack closure effect is proposed.In line with the theory of mechanical vibration,a dynamic model of crane structure during the working cycle is constructed,and dynamic coefficients under diverse actions are analysed.Calculation models of the internal force dynamic change process of dangerous cross-sections and a simulation model of first principal stress-time history are established by using the steel structure design criteria,which is utilised to extract the change of first principal stress of danger points over time.Then,the double-parameter stress spectrum is obtained by the rain flow counting method.The fatigue life calculation formula is corrected by introducing a crack closure parameter that can be calculated by the stress ratio and the effective stress ratio.Under the finite element model imported into Msc.Patran,crack propagation analysis is performed by the growth method in the fatigue integration module Msc.Fatigue.Taking the metal structure of a 100/40t-28.5m foundry crane with track offset as an example,the accuracy of calculation results and the feasibility and applicability of the proposed method are verified by theoretical calculation and finite element simulation,which provide a theoretical basis for improvement of the fatigue resistance design of foundry cranes. 展开更多
关键词 Metal structure of foundry crane load dynamic effect crack closure effect crack propagation fatigue life.
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Effect of electric field on the activity and quenching structure of liquid Cu-Al alloys 被引量:3
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作者 FajunGuo LingzhenLi YanbingZong DaqiangCang WenPan JunZhang 《Journal of University of Science and Technology Beijing》 CSCD 2005年第2期155-159,共5页
The activity coefficient of Al in molten Cu decreases with the increasing of electric current applied to the liquid alloy of Cu-0.2wt%Al. To investigate the mechanism, the quenching experimental results of the liquid... The activity coefficient of Al in molten Cu decreases with the increasing of electric current applied to the liquid alloy of Cu-0.2wt%Al. To investigate the mechanism, the quenching experimental results of the liquid Al-Cu alloy show that there is a re- markable change in structure, in which the solute congregates along the current direction especially for DC current. The mechanism of the activity coefficient change of Al in molten Cu-0.2wt%Al alloy treated by electrical field was discussed. Further, the results also provide an evidence for the short-range-ordered liquid metal. 展开更多
关键词 electrical field ACTIVITY liquid metal quenching structure liquid metal structure
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Design of the Metal Precursors Molecular Structures in Impregnating Solutions for Preparation of Efficient Ni Mo/Al_2O_3 Hydrodesulfurization Catalysts 被引量:12
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作者 Li Huifeng Li Mingfeng +2 位作者 Chu Yang Liu Feng Nie Hong 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2015年第4期37-45,共9页
The molecular structures of metal precursors in the impregnating solution were designed so as to prepare efficient Ni Mo/Al_2O_3 hydrodesulfurization(HDS) catalysts. At first, five typical impregnating solutions were ... The molecular structures of metal precursors in the impregnating solution were designed so as to prepare efficient Ni Mo/Al_2O_3 hydrodesulfurization(HDS) catalysts. At first, five typical impregnating solutions were designed; the existing metal precursors, such as [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species in the solutions were confirmed by laser Raman spectroscopy(LRS). The UV-Vis spectra results indicated that the solutions containing both phosphoric acid and citric acid could change the existing form of nickel species. Five corresponding Ni Mo/Al_2O_3 catalysts were prepared by the incipient wetness impregnation method. The LRS analysis results of dried catalysts showed that the above metal precursors could be partly retained on alumina support after impregnation and drying, although the interface reaction between different metal precursors and alumina support unavoidably took place. Then the catalysts were sulfided and characterized by N2 physisorption, TEM and XPS analyses. The results showed that different metal precursors in impregnating solution could mainly result in the difference in both the morphology of(Ni)Mo S2 slabs and the promoting effect of Ni species. The catalyst prepared mainly with [P2Mo5O23]^(6-)-like species used as precursors exhibited worse dispersion of(Ni)Mo S2 slabs and lower ratio of Ni–Mo–S active phases than the one with [Mo4(citrate)2O11]^(4-)-like species. Promisingly, the catalyst prepared with co-existing [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species showed better hydrodesulfurization activity for 4,6-DMDBT thanks to its more well-dispersed Ni–Mo–S active phases. 展开更多
关键词 molecular structures of metal precursors impregnating solution citric acid phosphorous hydrodesulfurization
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Safety evaluation system for hydraulic metal structures based on knowledge engineering 被引量:2
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作者 Yang Guangming Gu Chongshi 《Water Science and Engineering》 EI CAS 2008年第3期102-111,共10页
A comprehensive safety evaluation system taking the most influential factors into account has been developed to evaluate the reliability of hydraulic metal structures. Applying the techniques of AI and DB, the idea of... A comprehensive safety evaluation system taking the most influential factors into account has been developed to evaluate the reliability of hydraulic metal structures. Applying the techniques of AI and DB, the idea of a one-machine and three-base system is proposed. The framework of the three-base system has been designed and the structural framework constructed in turn. A practical example is given to illustrate the process of using this system and it can be used for comparison and analysis purposes. The key technology of the system is its ability to reorganize and improve the expert system's knowledge base by establishing the expert system. This system utilizes the computer technology inference process, making safety evaluation conclusions more reasonable and applicable to the actual situation. The system is not only advanced, but also feasible, reliable, artificially intelligent, and has the capacity to constantly grow. 展开更多
关键词 water conservancy and hydropower engineering safety evaluation one-machine and three-base system knowledge engineering hydraulic metal structure
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Synthesis and electrical characterization of tungsten oxide nanowires 被引量:3
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作者 黄睿 朱静 于荣 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第7期3024-3030,共7页
Tungsten oxide nanowires of diameters ranging from 7 to 200 nm are prepared on a tungsten rod substrate by using the chemical vapour deposition (CVD) method with vapour-solid (VS) mechanism.Tin powders are used to... Tungsten oxide nanowires of diameters ranging from 7 to 200 nm are prepared on a tungsten rod substrate by using the chemical vapour deposition (CVD) method with vapour-solid (VS) mechanism.Tin powders are used to control oxygen concentration in the furnace,thereby assisting the growth of the tungsten oxide nanowires.The grown tungsten oxide nanowires are determined to be of crystalline W18O49. I-V curves are measured by an in situ transmission electron microscope (TEM) to investigate the electrical properties of the nanowires.All of the I-V curves observed are symmetric,which reveals that the tungsten oxide nanowires are semiconducting. Quantitative analyses of the experimental I-V curves by using a metal semiconductor-metal (MSM) model give some intrinsic parameters of the tungsten oxide nanowires,such as the carrier concentration,the carrier mobility and the conductivity. 展开更多
关键词 tungsten oxide nanowires chemical vapour deposition (CVD) electrical characterization metal semiconductor metal (MSM) structure
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A Universal Principle to Accurately Synthesize Atomically Dispersed Metal–N_4 Sites for CO_2 Electroreduction 被引量:3
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作者 Wanzhen Zheng Feng Chen +7 位作者 Qi Zeng Zhongjian Li Bin Yang Lecheng Lei Qinghua Zhang Feng He Xilin Wu Yang Hou 《Nano-Micro Letters》 SCIE EI CAS CSCD 2020年第9期14-25,共12页
Atomically dispersed metal-nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction(CO2 ER),but they still suffer from the imprecisely control of type and coordinati... Atomically dispersed metal-nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction(CO2 ER),but they still suffer from the imprecisely control of type and coordination number of N atoms bonded with central metal.Herein,we develop a family of single metal atom bonded by N atoms anchored on carbons(SAs-M-N-C,M=Fe,Co,Ni,Cu)for CO2 ER,which composed of accurate pyrrole-type M-N4 structures with isolated metal atom coordinated by four pyrrolic N atoms.Benefitting from atomically coordinated environment and specific selectivity of M-N4 centers,SAs-Ni-N-C exhibits superior CO2 ER performance with onset potential of-0.3 V,CO Faradaic efficiency(F.E.) of 98.5%at-0.7 V,along with low Tafel slope of 115 mV dec-1 and superior stability of 50 h,exceeding all the previously reported M-N-C electrocatalysts for CO2-to-CO conversion.Experimental results manifest that the different intrinsic activities of M-N4 structures in SAs-M-N-C result in the corresponding sequence of Ni> Fe> Cu> Co for CO2 ER performance.An integrated Zn-CO2 battery with Zn foil and SAs-Ni-N-C is constructed to simultaneously achieve CO2-to-CO conversion and electric energy output,which delivers a peak power density of 1.4 mW cm-2 and maximum CO F.E.of 93.3%. 展开更多
关键词 Atomic dispersion Pyrrole-type metal–N4 structure Catalytic site CO2 electroreduction Zn–CO2 battery
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Evaluation of Ce(Ⅲ) and Gd(Ⅲ) adsorption from aqueous solution using CTS-g-(AA-co-SS)/ISC hybrid hydrogel adsorbent 被引量:6
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作者 王锋 王文波 +1 位作者 朱永峰 王爱勤 《Journal of Rare Earths》 SCIE EI CAS CSCD 2017年第7期697-708,共12页
CTS-g-(AA-co-SS)/ISC hybrid hydrogel adsorbent with crosslinked network structure and superior adsorption performance for rare-earth metal ions was successfully synthesized in aqueous solution by a simple one-step f... CTS-g-(AA-co-SS)/ISC hybrid hydrogel adsorbent with crosslinked network structure and superior adsorption performance for rare-earth metal ions was successfully synthesized in aqueous solution by a simple one-step free-radical grafting polymerization reaction among acrylic acid(AA), sodium p-styrenesulfonate(SS) and chitosan(CTS) using illite/smectite clay(ISC) as the inorganic additive. The structure of the as-prepared CTS-g-(AA-co-SS)/ISC hydrogel adsorbent was characterized, and the reaction parameters such as AA/SS molar ratio and ISC content were optimized, and the effects of pH values, initial concentration and contact time on the adsorption performance for Ce(Ⅲ) and Gd(Ⅲ) were systematically evaluated. It was found that the maximum adsorption capacities of the hydrogel adsorbent toward Ce(Ⅲ) and Gd(Ⅲ) reached 174.05 and 223.79 mg/g, respectively, and the adsorption quickly achieved equilibrium within 15–20 min. The adsorbed Ce(Ⅲ) and Gd(Ⅲ) could be easily desorbed for recovery, and the used adsorbent was able to be regenerated for reuse. After five adsorption-desorption cycles, the regenerated adsorbent could still retain the adsorption capacities that were close to the initial value. The adsorption process was well described by pseudo-second-order kinetic mode and the Langmuir isotherm model, and the chemical complexation between ions and –COO~–was mainly responsible for the high adsorption capacity. As a whole, the hybrid hydrogel adsorbent was potential to be used for the adsorption and recovery of Ce(Ⅲ) and Gd(Ⅲ) from water. 展开更多
关键词 rare-earth metals hybrid hydrogel network structure adsorption reuse
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