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Molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

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Journal of Iron and Steel Research International 2024年第2期31卷 488-500页

作者： tao-long xu Si-han Guo Gong-zhen He Hao-yu Han Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina Sichuan East Gas Transmission Sales Center of Sinopec Natural Gas Branch Wuhan430074HubeiChina

Hydrogen embrittlement of pipelines depends on the hydrogen-induced cracking behavior of the pipeline steel *** on molecular dynamics analysis,the ferrite–cementite(α-Fe/Fe3C)lamellar atomic structure with the Bagaryatskii orientation relationship was established,and stepwise relaxation of the conjugate gradient energy minimization and constant-temperature and constant-pressure relaxation were performed under NPT(the isothermal–isobaric)*** mechanical property curves of theα-Fe/Fe3C models were obtained under different cementite terminal plane structures,and the evolution of the atomic structure was analyzed in *** addition,the influence of different hydrogen concentrations,different temperatures,different strain rates,changes in voids,and different micro-degrees of freedom on the deformation and failure mechanism of the model was investigated,aiming to provide a reliable way to explore the micro-mechanism of macro-cracking behavior of pipeline steel.

关键词： Ferrite-cementite lamellar structure Pipeline steel Failure mechanism Crack propagation Molecular dynamics

Preparation and characterization of Rb-doped TiO_(2) powders for photocatalytic applications

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Rare Metals 2024年第2期43卷 555-561页

作者： Lu Jia Li-Mei Yang Wei Wang Song-tao Huang Zheng xu National Engineering Laboratory of Biohydrometallurgy General Research Institute for Nonferrous MetalsBeijing100088China

TiO_(2)nanoparticles doped with different concentrations of Rb were prepared by sol–gel *** crystal structures of samples were characterized by X-ray diffraction(XRD)and transmission electron microscopy(TEM).It was confirmed by the Rietveld refinement method that the as-prepared samples crystallize in anatase phase and Rb doping induces expansion and distortion of the crystal *** with the pure TiO_(2),the Rb-doped nanoparticles have smaller crystal size and better *** rate of methylene blue was used to evaluate the photocatalytic activity of Rb–TiO_(2).It indicated that doping Rb into TiO_(2)can effectively improve the photocatalytic activity of TiO_(2)and the mechanisms were discussed in *** using the sample doped with 0.20%Rb,methylene blue degraded with the fastest rate(97%within 60 min).

关键词： Rb doping TiO_(2) Photocatalysis Sol-gel

High-frequency magnetic properties of biphase Ce_(2)Fe_(17)N_(3)/α-Fe microflakes with easy-plane anisotropy

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Journal of Rare Earths 2024年第1期42卷 110-115,I0004页

作者： Ke Wang Hang Zhang Yuandong Huang Zhibiao xu Fashen Li tao Wang Key Laboratory for Magnetism and Magnetic Materials of MOE Lanzhou UniversityLanzhou730000China Key Laboratory of Special Function Materials and Structure Design Ministry of EducationLanzhou UniversityLanzhou730000China

Soft magnetic composites(SMCs)are effective as magnetic powder cores in an *** to high saturation magnetization,large magnetocrystalline anisotropy and high operating frequency of M(metal)-RE(rear earth)soft magnetic composites,it is possible to miniaturize inductor cores by reducing total loss,especially eddy current loss and excess loss at high *** this article,the characteristics of Ce_(2)Fe_(17)N_(3)/α-Fe(CFN/F)loss per volume and effective permeability reaching a high frequency of 3 MHz are *** biphase CFN/F composite exhibits a high permeability of 16 at 70 MHz,which is two times greater than that of pure Ce_(2)Fe_(17)N_(3)(CFN)*** total loss is as low as 545 mW/cm^(3)at 3 MHz and 6 *** direct current(DC)-bias properties have a percent of permeability exceeding 65% at H=7960 A/*** phenomenon indicates that our material has a higher working frequency and lower core loss than other materials;the biphase CFN/F structure is a promising and efficient approach for developing the miniaturized radio frequency(RF)inductor core.

关键词： High frequency Soft magnetic composites Easy-plane anisotropy Permeability spectra Core loss Rare earths

Adaptive detection of range-spread targets in homogeneous and partially homogeneous clutter plus subspace interference

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Journal of Systems Engineering and Electronics 2024年第1期35卷 43-54页

作者： JIAN tao HE Jia WANG Bencai LIU Yu xu Congan XIE Zikeng Research Institute of Information Fusion Naval Aviation UniversityYantai 264001China Air Force Early Warning Academy Wuhan 430019China

Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance *** target signal and interference are supposed to lie in two linearly independent subspaces with deterministic but unknown *** on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homogeneous clutter plus subspace interference,*** of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power *** results show that,the proposed detectors have better performance than their existing counterparts,especially for mismatches in the signal steering vectors.

关键词： adaptive detection subspace interference constant false alarm rate Gradient test partially homogeneous environment

A Two-Layer Encoding Learning Swarm Optimizer Based on Frequent Itemsets for Sparse Large-Scale Multi-Objective Optimization

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1342-1357页

作者： Sheng Qi Rui Wang tao Zhang xu Yang Ruiqing Sun Ling Wang College of Systems Engineering National University of Defense TechnologyChangsha 410073China Xiangjiang Laboratory Changsha 410205China College of Computer National University of Defense TechnologyChangsha 410073China Department of Automation Tsinghua UniversityBeijing 100084China IEEE

Traditional large-scale multi-objective optimization algorithms(LSMOEAs)encounter difficulties when dealing with sparse large-scale multi-objective optimization problems(SLM-OPs)where most decision variables are *** a result,many algorithms use a two-layer encoding approach to optimize binary variable Mask and real variable Dec ***,existing optimizers often focus on locating non-zero variable posi-tions to optimize the binary variables ***,approxi-mating the sparse distribution of real Pareto optimal solutions does not necessarily mean that the objective function is *** data mining,it is common to mine frequent itemsets appear-ing together in a dataset to reveal the correlation between *** by this,we propose a novel two-layer encoding learning swarm optimizer based on frequent itemsets(TELSO)to address these *** mined the frequent terms of multiple particles with better target values to find mask combinations that can obtain better objective values for fast ***-mental results on five real-world problems and eight benchmark sets demonstrate that TELSO outperforms existing state-of-the-art sparse large-scale multi-objective evolutionary algorithms(SLMOEAs)in terms of performance and convergence speed.

关键词： Evolutionary algorithms learning swarm optimiza-tion sparse large-scale optimization sparse large-scale multi-objec-tive problems two-layer encoding.

Molecular Generation and Optimization of Molecular Properties Using a Transformer Model

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Big Data Mining and Analytics 2024年第1期7卷 142-155页

作者： Zhongyin xu Xiujuan Lei Mei Ma yi Pan School of Computer Science Shaanxi Normal UniversityXi'an 710119China Faculty of Computer Science and Control Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Generating novel molecules to satisfy specific properties is a challenging task in modern drug discovery,which requires the optimization of a specific objective based on satisfying chemical ***,we aim to optimize the properties of a specific molecule to satisfy the specific properties of the generated *** Matched Molecular Pairs(MMPs),which contain the source and target molecules,are used herein,and logD and solubility are selected as the optimization *** main innovative work lies in the calculation related to a specific transformer from the perspective of a matrix *** intervals and state changes are then used to encode logD and solubility for subsequent *** the experiments,we screen the data based on the proportion of heavy atoms to all atoms in the groups and select 12365,1503,and 1570 MMPs as the training,validation,and test sets,*** models are compared with the baseline models with respect to their abilities to generate molecules with specific *** show that the transformer model can accurately optimize the source molecules to satisfy specific properties.

关键词： molecular optimization transformer Matched Molecular Pairs(MMPs) logD solubility

A Novel 3D Gait Model for Subject Identification Robust against Carrying and Dressing Variations

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Computers, Materials & Continua 2024年第7期80卷 235-261页

作者： Jian Luo Bo xu Tardi Tjahjadi Jian yi College of Information Science and Engineering Hunan Normal UniversityChangsha410000China School of Engineering University of WarwickCoventryCV47ALUK

Subject identification via the subject’s gait is challenging due to variations in the subject’s carrying and dressing conditions in real-life *** paper proposes a novel targeted 3-dimensional(3D)gait model(3DGait)represented by a set of interpretable 3DGait descriptors based on a 3D parametric body *** 3DGait descriptors are utilised as invariant gait features in the 3DGait recognition method to address object carrying and *** 3DGait recognitionmethod involves 2-dimensional(2D)to 3DGaitdata learningbasedon3Dvirtual samples,a semantic gait parameter estimation Long Short Time Memory(LSTM)network(3D-SGPE-LSTM),a feature fusion deep model based on a multi-set canonical correlation analysis,and SoftMax recognition ***,a sensory experiment based on 3D body shape and pose deformation with 3D virtual dressing is used to fit 3DGait onto the given 2D gait images.3Dinterpretable semantic parameters control the 3D morphing and dressing *** degree measurement determines the semantic descriptors of 2D gait images of subjects with various shapes,poses and ***,using the 2D gait images as input and the subjects’corresponding 3D semantic descriptors as output,an end-to-end 3D-SGPE-LSTM is constructed and ***,body shape,pose and external gait factors(3D-eFactors)are estimated using the 3D-SGPE-LSTM model to create a set of interpretable gait descriptors to represent the 3DGait Model,i.e.,3D intrinsic semantic shape descriptor(3DShape);3D skeleton-based gait pose descriptor(3D-Pose)and 3D dressing with other ***,the 3D-Shape and 3D-Pose descriptors are coupled to a unified pattern space by learning prior knowledge from the *** research on CASIA B,CMU MoBo,TUM GAID and GPJATK databases shows that 3DGait is robust against object carrying and dressing variations,especially under multi-cross variations.

关键词： Gait recognition human identification three-dimensional gait canonical correlation analysis

Energy-Saving Distributed Flexible Job Shop Scheduling Optimization with Dual Resource Constraints Based on Integrated Q-Learning Multi-Objective Grey Wolf Optimizer

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1459-1483页

作者： Hongliang Zhang yi Chen Yuteng Zhang Gongjie xu School of Management Science and Engineering Anhui University of TechnologyMa’anshan243032China Laboratory of Multidisciplinary Management and Control of Complex Systems of Anhui Higher Education Institutes Anhui University of TechnologyMa’anshan243032China Department of Industrial Engineering School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an710072China

The distributed flexible job shop scheduling problem(DFJSP)has attracted great attention with the growth of the global manufacturing *** DFJSP research only considers machine constraints and ignores worker *** one critical factor of production,effective utilization of worker resources can increase ***,energy consumption is a growing concern due to the increasingly serious environmental ***,the distributed flexible job shop scheduling problem with dual resource constraints(DFJSP-DRC)for minimizing makespan and total energy consumption is studied in this *** solve the problem,we present a multi-objective mathematical model for DFJSP-DRC and propose a Q-learning-based multi-objective grey wolf optimizer(Q-MOGWO).In Q-MOGWO,high-quality initial solutions are generated by a hybrid initialization strategy,and an improved active decoding strategy is designed to obtain the scheduling *** further enhance the local search capability and expand the solution space,two wolf predation strategies and three critical factory neighborhood structures based on Q-learning are *** strategies and structures enable Q-MOGWO to explore the solution space more efficiently and thus find better Pareto *** effectiveness of Q-MOGWO in addressing DFJSP-DRC is verified through comparison with four algorithms using 45 *** results reveal that Q-MOGWO outperforms comparison algorithms in terms of solution quality.

关键词： Distributed flexible job shop scheduling problem dual resource constraints energy-saving scheduling multi-objective grey wolf optimizer Q-learning

Chiral transfer amidst one-dimensional linear polymers and twodimensional network covalent organic frameworks:Striking a fine balance between helicity and crystallinity

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Nano Research 2024年第6期17卷 5726-5734页

作者： Xinlin Zha Mengjuan Zuo Guilin xu Zhong Yan Haining You yi Xiong ying Liu yingying Li Liyan Yang Ke Liu Mufang Li tao Zhao Dong Wang College of Chemistry and Chemical Engineering Donghua UniversityShanghai 201620China Key Laboratory of Textile Fiber and Products Ministry of EducationWuhan Textile UniversityWuhan 430200China

The current landscape of chiral covalent organic frameworks(COFs)predominantly centered on constructing asymmetric molecular-scale chirality,often introducing an inherent contradiction to the COF symmetry and limiting ***,we overcome these challenges by achieving chiral transfer between one-dimensional(1D)imine linear polymers(LPs)and two-dimensional(2D)networkβ-ketoenamine COFs composed of achiral *** successfully synthesize several 1D imine LPs with mesoscopic helical chirality,comprising achiral C2-symmetric terephthalaldehyde and diamine linkers in a chiral supramolecular transcription *** the irreversible tautomerism mechanism within the linker replacement approach,terephthalaldehyde(TPA)units in these helical 1D LPs are substituted with C3-symmetric 1,3,5-triformylphloroglucinol(TP),yielding the corresponding 2D networkβ-ketoenamine *** and helicity of the resultantβ-ketoenamine COFs intimately hinge on reaction conditions,including the aldehyde stoichiometry of Tp and TPA,as well as the quantity and concentration of the catalyst *** optimized conditions,the nucleation and growth were precisely governed,achieving a harmonious equilibrium of crystallinity and helicity within the generated 2D networkβ-ketoenamine COFs,even with covalent bond rupture,recombination,and topological transition(from[C2+C2]to[C3+C2]).Impressively,the ground state chirality inherent to helical 1D LPs seamlessly transfers to helical 2D networkβ-ketoenamine *** study not only offers new perspectives on the development of chiral functional COFs,but also provides fresh insights into the precise control of COFs'microscopic morphology.

关键词： chiral covalent organic frameworks chiral transfer dimensional transformation helicity