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Tension-Compression Asymmetry in Ultrafine-grained Commercially Pure Ti Processed by ECAP

Journal of Wuhan University of technology(Materials Science) 2023年第3期38卷 689-694页

作者：刘晓燕 LI Shuaikang YANG Xirong LUO Lei School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055China

A homogenous microstructure of ultrafine-grained (UFG) commercially pure (CP) Ti characterized by equiaxed grains/subgrains with an average grain size of about 150 nm and strong prismatic fiber texture were obtained after 4 passes of equal channel angular pressing (ECAP).Tension–compression asymmetry in yield and work hardening behavior of UFG CP Ti were investigated by uniaxial tension and compression *** experimental results reveal that UFG CP Ti exhibits a relatively obvious tensioncompression asymmetry in yielding and work hardening *** basal and prismaticslip are suppressed either for tension or compression,which is the easiest to *** tension twin system{1012}<1011> easily activated in compression deformation due to the prismatic fiber texture based on the Schmidt factor,consequently resulting in a lower yield strength under compression than *** can improve the tension-compression asymmetry of CP Ti due to grain *** interaction among the dislocations,grain boundaries and deformation twins are the main work hardening mechanisms for compression deformation,while the interaction between the dislocations and grain boundaries for tension *** twins lead to the higher work hardening under compression than tension.

关键词： ultrafine-grained commercially pure Ti equal channel angular pressing tensioncompression asymmetry texture twinning

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Influencer identification of dynamical networks based on an information entropy dimension reduction method

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Chinese Physics B 2024年第4期33卷 375-384页

作者：段东立纪思源袁紫薇 School of Information and Control Engineering Xi'an University of Architecture and TechnologyXi'an 710311China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China

Identifying critical nodes or sets in large-scale networks is a fundamental scientific problem and one of the key research directions in the fields of data mining and network science when implementing network attacks, defense, repair and *** methods usually begin from the centrality, node location or the impact on the largest connected component after node destruction, mainly based on the network ***, these algorithms do not consider network state *** applied a model that combines a random connectivity matrix and minimal low-dimensional structures to represent network *** using mean field theory and information entropy to calculate node activity,we calculated the overlap between the random parts and fixed low-dimensional parts to quantify the influence of node impact on network state changes and ranked them by *** applied this algorithm and the proposed importance algorithm to the overall analysis and stratified analysis of the *** neural *** observed a change in the critical entropy of the network state and by utilizing the proposed method we can calculate the nodes that indirectly affect muscle cells through neural layers.

关键词： dynamical networks network influencer low-dimensional dynamics network disintegration

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Prediction of collapse process and tipping points for mutualistic and competitive networks with k-core method

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Chinese Physics B 2024年第5期33卷 173-180页

作者：段东立毕菲菲李思凡吴成星吕长春蔡志强 School of Information and Control Engineering Xi'an University of Architecture and TechnologyXi'an 710311China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China

Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called ***,once the external disturbances exceed the tipping points of the system resilience,the consequences would be catastrophic,and eventually lead the ecosystem to complete *** capture the collapse process of ecosystems represented by plant-pollinator networks with the k-core nested structural method,and find that a sufficiently weak interaction strength or a sufficiently large competition weight can cause the structure of the ecosystem to collapse from its smallest k-core towards its largest *** we give the tipping points of structure and dynamic collapse of the entire system from the one-dimensional dynamic function of the *** work provides an intuitive and precise description of the dynamic process of ecosystem collapse under multiple interactions,and provides theoretical insights into further avoiding the occurrence of ecosystem collapse.

关键词： complex networks tipping points dimension reduction k-core

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Re-delocalization of localized d-electrons in VO_(2)(R)-VS_(4)hetero-structure enables high performance of rechargeable Mg-ion batteries

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Journal of Magnesium and Alloys 2024年第5期12卷 1830-1840页

作者： Lijiao Zhou Chao Shen Xueyang Hou Zhao Fang Ting Jin Keyu Xie School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’an 710072China School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons ***,the reversible Mg^(2+)diffusion in cathode materials is restricted by the strong interactions between the high-polarized bivalent Mg^(2+)ions and anionic ***,we design and propose a hetero-structural VO_(2)(R)-VS_(4)cathode,in which the re-delocalized d-electrons can effectively shield the polarity of Mg^(2+)***,the electrons should spontaneously transfer from VS_(4)to VO_(2)(R)through the interfaces of hetero-structure due to the lower work function value of VS_(4).Furthermore,the internal electrons transfer lead to the electronic injection into VO_(2)(R)from VS_(4)and the partially broken V-V dimers,indicating the presence of lone pair electrons and charge *** from the shield effect of re-delocalized electrons,and the weakened attraction between cations and O/S anions enables more S^(2-)-S_(2)^(2-)redox groups to participate the electrochemical reactions and compensate the double charge of Mg^(2+)***,VO_(2)(R)-VS_(4)hetero-structure exhibits a high specific capacity of 554 mA h g^(-1)at 50 mA g^(-1).It is believed that the charge re-delocalization of cathode extremely boost the Mg^(2+)ions migration for the high-capacity of MIBs.

关键词： Mg-ion batteries Cathode Charge delocalization Electronic structure Heterostructure

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Dual-phase enhancement strategy for Li_(4)Ti_(5)O_(12)-TiO_(2) and other anodes in Li/Mg ion batteries

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Nano Research 2025年第2期18卷 298-316页

作者： Meijia Song Lefei Li Xiuzhen Wang School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212000China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212000China

The *** for portable and environmentally sustainableenergyfor use in the electronic/electrical equipment,automobile,and so on has resulted in an ever-increasing development in the rechargeable metal-ion-battery *** anode is a crucial component of the battery system,influencing both the cost and overall performance of the *** optimize the electrochemical properties of anode materials,constructing the dual-phase structure has been identified as an effective *** mutual buffering between phases helps alleviate dramatic volume changes,while the abundant interfaces increase active sites and enhance the ion *** this review,the research and development of main anode materials with dual-phase configurations in Li/Mg ion batteries are summarized and *** fabrication methods,regulation strategy,electrochemical performance,as well as enhancement mechanisms of dual-phase Li_(4)Ti_(5)O_(12)-TiO_(2) composites,TiO_(2)-based composites,alloy-type materials,and other types of dual-phase anodes are reviewed and compared in ***,some perspectives about the future progress of dual-phase anode materials for metal-ion batteries are proposed.

关键词： anode materials Li_(4)Ti_(5)O_(12)-TiO_(2)anodes dual-phase configuration progress and development

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Homogeneous distributed natural pyrite-derived composite induced by modified graphite as high-performance lithium-ion batteries anode

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International Journal of Minerals,Metallurgy and Materials 2023年第7期30卷 1353-1362页

作者： Juan Yu Yinbo Wei Bicheng Meng Jiaxin Peng Kai Yang Tianxing Chen Naixing Yang Xiuyun Chuan School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China School of Earth and Space Sciences Peking UniversityBeijing 100871China Shaanxi Key Laboratory of Nano-Materials and Technology School of Mechanical and Electrical EngineeringXi’an University of Architecture and TechnologyXi’an 710055China School of Resources Engineering Xi’an University of Architecture TechnologyXi’an 710055China

Natural minerals-based energy materials have attracted enormous attention because of the advantages of good materials consistency,high production,environmental friendliness,and low *** uniform distribution of grains can effectively inhibit the aggregation of active materials,improving lithium storage *** this work,natural graphite is modified by polyvinylpyrrolidone to obtain modified graphite with reduced size and better *** pyrite composite polyvinylpyrrolidone-modified graphite(pyrite/PG)material with uniform particle distribution is obtained by the ball milling *** subsequent calcination process converts pyrite/PG into Fe_(1-x)Scompounded with polyvinylpyrrolidone-modified graphite(Fe_(1-x)S/PG).The homogeneous grain distributions of active material can facilitate the faster transfer of electrons and promote the efficient utilization of active *** as-prepared Fe_(1-x)S/PG electrode exhibits a remarkably reversible specific capacity of 613.0 mAh·g^(-1)at 0.2 A·g^(-1)after 80 cycles and an excellent rate capability of 523.0 mAh·g^(-1)at 5 A·g^(-1).Even at a higher current density of 10 A·g^(-1),it can deliver a specific capacity of 348.0 mAh·g^(-1).Moreover,the dominant pseudocapacitance in redox reactions accounts for the impressive rate and cycling *** work provides a low-cost and facile method to fabricate natural mineral-based anode materials and apprise readers about the impact of uniform particle distribution on lithium storage performance.

关键词： natural pyrite modified graphite anode lithium-ion batteries homogeneous grain distributions

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A benchmark-based method for evaluating hyperparameter optimization techniques of neural networks for surface water quality prediction

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Frontiers of Environmental Science & engineering 2024年第5期18卷 13-27页

作者： Xuan Wang Yan Dong Jing Yang Zhipeng Liu Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an710055China State Key Laboratory of Green Building in West China Xi’an University of Architecture and TechnologyXi’an710055China

Neural networks(NNs)have been used extensively in surface water prediction tasks due to computing algorithm improvements and data *** essential step in developing an NN is the hyperparameter *** practice,it is common to manually determine hyperparameters in the studies of NNs in water resources *** may result in considerable randomness and require significant computation time;therefore,hyperparameter optimization(HPO)is *** study adopted five representatives of the HPO techniques in the surface water quality prediction tasks,including the grid sampling(GS),random search(RS),genetic algorithm(GA),Bayesian optimization(BO)based on the Gaussian process(GP),and the tree Parzen estimator(TPE).For the evaluation of these techniques,this study proposed a method:first,the optimal hyperparameter value sets achieved by GS were regarded as the benchmark;then,the other HPO techniques were evaluated and compared with the benchmark in convergence,optimization orientation,and consistency of the optimized *** results indicated that the TPE-based BO algorithm was recommended because it yielded stable convergence,reasonable optimization orientation,and the highest consistency rates with the benchmark *** optimization consistency rates via TPE for the hyperparameters hidden layers,hidden dimension,learning rate,and batch size were 86.7%,73.3%,73.3%,and 80.0%,*** the evaluation of HPO techniques directly based on the prediction performance of the optimized NN in a single HPO test,the proposed benchmark-based HPO evaluation approach is feasible and robust.

关键词： Neural networks Hyperparameter optimization Surface water quality prediction Bayes optimization Genetic algorithm

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Self-Tuning of MPC Controller for Mobile Robot Path Tracking Based on Machine Learning

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Journal of Shanghai Jiaotong university(Science) 2024年第6期29卷 1028-1036页

作者： LIU Yuesheng HE Ning HE Lile ZHANG Yiwen XI Kun ZHANG Mengrui School of Mechatronic Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

Model predictive control(MPC)is a model-based optimal control strategy widely used in robot *** this work,the MPC controller tuning problem for the path tracking of the wheeled mobile robot is studied and a novel self-tuning approach is ***,two novel path tracking performance indices,i.e.,steadystate time ratio and steady-state distance ratio are proposed to more accurately reflect the control ***,the mapping relationship between the proposed indices and the MPC parameters is established based on machine learning technique,and then a novel controller structure which can automatically tune the control parameters online is further ***,experimental verification with an actual wheeled mobile robot is conducted,which shows that the proposed method could outperform the existing method via achieving significant improvement in the rapidity,accuracy and adaptability of the robot path tracking.

关键词： model predictive control(MPC) path tracking mobile robot machine learning parameter tuning

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Coupling Effect of Cryogenic Freeze-Thaw Cycles and Chloride Ion Erosion Effect in Pre-Cracked Reinforced Concrete

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Structural Durability & Health Monitoring 2024年第3期18卷 255-276页

作者： Yang Li Sibo Jiang Ruixin Lan School of Civil Engineering and Architecture Hubei University of TechnologyWuhan430068China

Chloride (Cl−) ion erosion effects can seriously impact the safety and service life of marine liquefied natural gas(LNG) storage tanks and other polar offshore structures. This study investigates the impact of different low-temperaturecycles (20°C, –80°C, and −160°C) and concrete specimen crack widths (0, 0.3, and 0.6 mm) on the Cl−ion diffusion performance through rapid erosion tests conducted on pre-cracked concrete. The results show thatthe minimum temperature and crack width of freeze-thaw cycles enhance the erosive effect of chloride ions. TheCl− ion concentration and growth rate increased with the increasing crack width. Based on the experimental modeland in accordance with Fick’s second law of diffusion, the Cl− ion diffusion equation was modified by introducingcorrection factors in consideration of the freeze-thaw temperature, crack width, and their coupling *** experimental and fitting results obtained from this model can provide excellent reference for practical engineeringapplications.

关键词： Chloride ions freeze-thaw cycles cracks

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Effect of NaCl Concentration on the Cumulative Strain and Pore Distribution of Clay under Cyclic Loading

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Fluid Dynamics & Materials Processing 2024年第2期20卷 447-461页

作者： Xinshan Zhuang Shunlei Xia Ruijie Pan School of Civil Engineering and Architecture Hubei University of TechnologyWuhan430068China

Clay,as the most common soil used for foundationﬁll,is widely used in various infrastructure *** phy-sical and mechanical properties of clay are inﬂuenced by the pore solution *** study uses a GDS static/dynamic triaxial apparatus and nuclear magnetic resonance experiments to investigate the effects of cyclic loading on clay ***,the development of cumulative strain in clay is analyzed,and aﬁtting model for cumulative plastic strain is introduced by considering factors such as NaCl solution concentration,con-solidation stress ratio,and cycle *** particular,the effects of the NaCl solution concentration and con-solidation stress ratio on the pore distribution of the test samples before and after cyclic loading are examined,and the relationship between microscopic pore size and macroscopic cumulative strain is obtained *** results show that as the consolidation stress ratio grows,an increasing number of large pores in the soil samples are transformed into small *** the NaCl solution concentration becomes higher,the number of small pores gradually decreases,while the number of large pores remains *** loading causes the disappearance of the large pores in the samples,and the average pore size before cyclic loading is posi-tively correlated with the axial cumulative strain after cyclic *** cumulative strain produced by the soil under cyclic loading is inversely proportional to the NaCl solution concentration and consolidation stress ratio.

关键词： Geotechnical engineering clay cyclic loading nuclear magnetic resonance NaCl solution consolidation ratio accumulative strain

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