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Customized heat treatment process enabled excellent mechanical properties in wire arc additively manufactured Mg-RE-Zn-Zr alloys

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International Journal of Extreme Manufacturing 2024年第4期6卷 276-289页

作者： Dong Ma Chunjie Xu Shang Sui Yuanshen Qi Can Guo Zhongming Zhang Jun Tian Fanhong Zeng Sergei Remennik Dan Shechtman School of Materials Science and Engineering Xi'an University of TechnologyXi'anShaanxi 710048People's Republic of China Xi'an Shechtman Nobel Prize New Materials Institute Xi'an 710048People's Republic of China Xi'an Key Laboratory of Advanced Magnesium Alloy Additive Manufacturing and Precision Forming Xi'anShaanxi 710048People's Republic of China department of Materials Science and Engineering and Guangdong provincial Key Laboratory of Materials and Technologies for Energy Conversion Guangdong Technion—Israel Institute of TechnologyShantou 515063People's Republic of China MGM Nobel Prize New Materials Co. LtdTongchuan 727100People's Republic of China department of Materials Science and Engineering Technion-Israel Institute of TechnologyHaifa 32000Israel Center for Nanoscience&Nanotechnology Hebrew University of JerusalemEdmond J.Safra CampusJerusalem 91904Israel

Customized heat treatment is essential for enhancing the mechanical properties of additively manufactured metallic materials,especially for alloys with complex phase constituents and heterogenous ***,the interrelated evolutions of different microstructure features make it difficult to establish optimal heat treatment ***,we proposed a method for customized heat treatment process exploration and establishment to overcome this challenge for such kind of alloys,and a wire arc additively manufactured(WAAM)Mg-Gd-Y-Zn-Zr alloy with layered heterostructure was used for feasibility *** this method,the optimal microstructures(fine grain,controllable amount of long period stacking ordered(LPSO)structure and nano-scaleβ'precipitates)and the corresponding customized heat treatment processes(520°C/30 min+200°C/48 h)were obtained to achieve a good combination of a high strength of 364 MPa and a considerable elongation of 6.2%,which surpassed those of other state-of-the-art WAAM-processed Mg ***,we evidenced that the favorable effect of the undeformed LPSO structures on the mechanical properties was emphasized only when the nano-scaleβ'precipitates were *** is believed that the findings promote the application of magnesium alloy workpieces and help to establish customized heat treatment processes for additively manufactured materials.

关键词： wire arc additive manufacturing heat treatment Mg-RE-Zn-Zr alloys LPSO structure mechanical properties

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A Survey of Crime Scene Investigation Image Retrieval Using Deep Learning

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Journal of Beijing Institute of Technology 2024年第4期33卷 271-286页

作者： Ying Liu Aodong Zhou Jize Xue Zhijie Xu Xi’an University of Posts and Telecommunications(XUPT) Xi’an 710121China University of Huddersfield Huddersfield HD13DHUK

Crime scene investigation(CSI)image is key evidence carrier during criminal investiga-tion,in which CSI image retrieval can assist the public police to obtain criminal ***,with the rapid development of deep learning,data-driven paradigm has become the mainstreammethod of CSI image feature extraction and representation,and in this process,datasets provideeffective support for CSI retrieval ***,there is a lack of systematic research onCSI image retrieval methods and ***,we present an overview of the existing worksabout one-class and multi-class CSI image retrieval based on deep *** to theresearch,based on their technical functionalities and implementation methods,CSI image retrievalis roughly classified into five categories:feature representation,metric learning,generative adversar-ial networks,autoencoder networks and attention ***,We analyzed the remain-ing challenges and discussed future work directions in this field.

关键词： crime scene investigation(CSI)image image retrieval deep learning

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Metarelation2vec:A Metapath-Free Scalable Representation Learning Model for Heterogeneous Networks

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Tsinghua Science and Technology 2024年第2期29卷 553-575页

作者： Lei Chen Yuan Li Yong Lei Xingye Deng School of Information and Electrical Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Computer Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China

Metapaths with specific complex semantics are critical to learning diverse semantic and structural information of heterogeneous networks(HNs)for most of the existing representation learning ***,any metapaths consisting of multiple,simple metarelations must be driven by domain *** sensitive,expensive,and limited metapaths severely reduce the flexibility and scalability of the existing models.A metapath-free,scalable representation learning model,called Metarelation2vec,is proposed for HNs with biased joint learning of all metarelations in a bid to address this ***,a metarelation-aware,biased walk strategy is first designed to obtain better training samples by using autogenerating cooperation probabilities for all metarelations rather than using expert-given ***,grouped nodes by the type,a common and shallow skip-gram model is used to separately learn structural proximity for each node ***,grouped links by the type,a novel and shallow model is used to separately learn the semantic proximity for each link ***,supervised by the cooperation probabilities of all meta-words,the biased training samples are thrown into the shallow models to jointly learn the structural and semantic information in the HNs,ensuring the accuracy and scalability of the *** experimental results on three tasks and four open datasets demonstrate the advantages of our proposed model.

关键词： metarelation random walk heterogeneous network metapath representation learning

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含相变材料的充填体内置采热管群热压性能研究

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Journal of Central South University 2024年第2期31卷 649-669页

作者：张小艳杜强强刘浪许慕妍柯亚萍王雪丽 Energy School Xi’an University of Science and TechnologyXi’an 710054China School of Architecture and Civil Engineering Xi’an University of Science and TechnologyXi’an 710054China Key Laboratory of Western Mines and Hazards Prevention Ministry of EducationXi’an 710054China Shenzhen iTeaQ Network Power Technology Co. Ltd.Shenzhen 518110China

通过将采热管群与充填采矿技术相结合可提取矿井中的地热能,有效缓解高地热带来的热害问题。本文以采热管群为研究对象,分析了充填体放热过程中传热流体的温度、速度和压力分布,讨论了雷诺数、管径、管间距和管排方式对采热管群性能的... 详细信息

通过将采热管群与充填采矿技术相结合可提取矿井中的地热能,有效缓解高地热带来的热害问题。本文以采热管群为研究对象,分析了充填体放热过程中传热流体的温度、速度和压力分布,讨论了雷诺数、管径、管间距和管排方式对采热管群性能的影响。结果表明:当雷诺数从100增加到5000时,换热量从2.24×10^(3)kJ增加到16.78×10^(3)kJ,综合评价因子从0.087增加到1.31。当管径从4 mm增加到6 mm时,换热量从15.07×10^(3)kJ增加到17.11×10^(3)kJ,综合评价因子从1.157增加到1.388。当管间距从130 mm增加到170 mm时,换热量从14.24×10^(3)kJ增加到16.25×10^(3)kJ,综合评价因子从1.013增加到1.263。此外,四路并联布置可以保证较高的换热量和较低的压降,从而获得较高的综合评价因子。该研究为充填体中采热管群的设计和优化提供了理论参考。

关键词：采热管群充填体换热压降综合性能

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Bifurcations and Spatiotemporal Patterns in the Diffusive Nutrient-Microorganism Model

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Acta Mathematicae Applicatae Sinica 2024年

作者： Ya-di WANG Hai-long YUAN Yan-ling LI School of Arts and Sciences Shaanxi University of Science and Technology School of Mathematics and Statistics Xi'an Jiaotong University School of Mathematics and Information Science Shaanxi Normal University

In this paper, the diffusive nutrient-microorganism model subject to Neumann boundary conditions is considered. The Hopf bifurcations and steady state bifurcations which bifurcate from the positive constant equilibrium of the system are investigated in details. In addition, the formulae to determine the direction of Hopf and steady state bifurcations are derived. Our results show the existence of spatially homogeneous/nonhomogeneous periodic orbits and steady state solutions, which indicates the spatiotemporal dynamics of the system. Some numerical simulations are also presented to support the analytical results.

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Polarization control of above-threshold ionization spectrum in elliptically polarized two-color laser fields

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Chinese Physics B 2024年第4期33卷 136-144页

作者：金发成杨慧慧宋晓红李飞杜玲玲薛红杰魏丽敏白悦刘浩翔王兵兵杨玮枫 Faculty of Science Xi'an Aeronautical InstituteXi'an 710077China School of Physics and Optoelectronic Engineering Hainan UniversityHaikou 570288China Center for Theoretical Physics Hainan UniversityHaikou 570288China Laboratory of Optical Physics Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing 100190China College of Science Shantou UniversityShantou 515063China University of Chinese Academy of Sciences Beijing 100049China

We study the above-threshold ionization(ATI)process of atoms exposed to fundamental and high-frequency lasers with arbitrary ellipticity by applying the frequency-domain *** is found that the angular-resolved ATI spectrum is sensitive to ellipticities of two lasers and emitted angles of the *** for the photon energy of the highfrequency laser more than atomic ionization potential,the width of plateau tends to a constant with increasing ellipticity of fundamental field,the dip structure disappears with increasing ellipticity of the high-frequency *** the help of the quantum channel analysis,it is shown that the angular distribution depends mainly on the ellipticity of high-frequency field in the case that its frequency is ***,one can see that the maximal and minimal energies in quantum numerical results are in good agreement with the classical *** investigation may provide theoretical support for experimental research on polarization control of ionization in elliptically polarized two-color laser fields.

关键词： above-threshold ionization two-color laser polarization control

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Design and parameter optimization of air-suction wheel type of seedmetering device with elastic pad for maize

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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 116-127页

作者： Yuhuan Sun Junhai Guo Linrong Shi College of Mechanical and Electrical Engineering Gansu Agricultural UniversityLanzhou 730070China College of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730070China

Due to the maize growing agronomy requires ground covered by mulch film in the arid zones of the China Northwest region,the seed-metering device must roll over,break the film,and then throw seeds into ***,the uneven ground can cause the seed-metering device to shake,reducing seed-metering *** improve the adaptability for different shapes of maize seeds,a air suction wheel type seed-metering device with elastic pad was developed for better seed extraction and bump ***,the advantages and influencing factors of the elastic pad were analyzed through four processes of metering ***,the velocity distributions of six diameters of the suction hole are compared to determine the range with ***,a one-factor experiment was conducted to analyze the pattern of the factors(the seed layer height,the critical vacuum,the rotational speed of the seed disk,and the suction hole diameter)influencing the metering seed ***,a five-level quadratic rotation orthogonal design was used to optimize the *** show that the optimal values are that the seed layer height is 40 mm,and the critical vacuum is 2.85 kPa,and the rotational speed of the seed disk is 20.1 r/*** validation experiment resulted in a 93.79%qualified index,with a 4.02%missing index and a 2.19%multiple index.

关键词： maize seeds seed-metering device with air suction elastic suction parameter optimization

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Effect of Rigid Pitch Motion on Flexible Vibration Characteristics of a Wind Turbine Blade

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Energy Engineering 2024年第10期121卷 2981-3000页

作者： Zhan Wang Liang Li Long Wang Weidong Zhu Yinghui Li Echuan Yang School of Mechanical Engineering Anhui University of Science and TechnologyHuainan232001China School of Mechanics and Optoelectronic Physics Anhui University of Science and TechnologyHuainan232001China department of Mechanical Engineering University of MarylandBaltimoreMD 21250USA School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu610031China School of Mechanical Engineering Chongqing University of TechnologyChongqing400054China

Adynamic pitch strategy is usually adopted to improve the aerodynamic performance of the blade of awind *** dynamic pitch motion will affect the linear vibration characteristics of the ***,these influences have not been studied in previous *** this paper,the influences of the rigid pitch motion on the linear vibration characteristics of a wind turbine blade are *** blade is described as a rotating cantilever beam with an inherent coupled rigid-flexible vibration,where the rigid pitch motion introduces a parametrically excited vibration to the *** differential equations governing the nonlinear coupled pitch-bend vibration are proposed using the generalized Hamiltonian *** vibration characteristics of the inherent coupled rigid-flexible system are analyzed based on the combination of the assumed modes method and the multi-scales *** of static pitch angle,rotating speed,and characteristics of harmonic pitch motion on flexible natural frequencies andmode shapes are *** shows that the pitch amplitude has a dramatic influence on the natural frequencies of the blade,while the effects of pitch frequency and pith phase on natural frequencies are little.

关键词： Pitch motion wind turbine blade inherent rigid-flexible coupling vibration characteristics

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Absorption properties and mechanism of lightweight and broadband electromagnetic wave-absorbing porous carbon by the swelling treatment

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1701-1712页

作者： Jianghao Wen Di Lan Yiqun Wang Lianggui Ren Ailing Feng Zirui Jia Guanglei Wu College of Materials and Chemistry&Chemical Engineering Chengdu University of TechnologyChengdu 610059China School of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002China Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China Institute of Physics&Optoelectronics Technology Baoji University of Arts and SciencesBaoji 721016China

Bioderived carbon materials have garnered considerable interest in the fields of microwave absorption and shielding due to their reproducibility and environmental *** this study,KOH was evenly distributed on biomass Tremella using the swelling induction method,leading to the preparation of a three-dimensional network-structured hierarchical porous carbon(HPC)through *** achieved microwave absorption intensity is robust at-47.34 dB with a thin thickness of 2.1 ***,the widest effective absorption bandwidth,reaching 7.0 GHz(11–18 GHz),is attained at a matching thickness of 2.2 *** exceptional broadband and reflection loss performance are attributed to the 3D porous networks,interface effects,carbon network defects,and dipole *** has outstanding absorption characteristics due to its excellent impedance matching and high attenuation *** uniform pore structures considerably optimize the impedance-matching performance of the material,while the abundance of interfaces and defects enhances the dielectric loss,thereby improving the attenuation ***,the impact of carbonization temperature and swelling rate on microwave absorption performance was systematically *** research presents a strategy for preparing absorbing materials using biomass-derived HPC,showcasing considerable potential in the field of electromagnetic wave absorption.

关键词： biomass hierarchical porous carbon dielectric loss electromagnetic wave absorption

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利用测井资料评价煤层气可采性

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Applied Geophysics 2024年第2期21卷 265-278,419页

作者：刘之的杨斌睿汤小燕王伟纪亮蒋志浩西安石油大学地球科学与工程学院西安710065 西安石油大学陕西省油气成藏地质重点实验室西安710065 西安科技大学地质与环境学院西安710054 中国石油煤层气有限公司西安分公司陕西西安714000

精准评价煤层气可采性,对于制定压裂排采方案至关重要。本文以鄂东气田韩城矿区煤储层为研究对象,充分利用测井、煤岩心化验分析及排采动态测试资料,对影响煤储层完井品质的煤体结构指数、煤岩脆性指数、地应力差异系数进行了计算,并构... 详细信息

精准评价煤层气可采性,对于制定压裂排采方案至关重要。本文以鄂东气田韩城矿区煤储层为研究对象,充分利用测井、煤岩心化验分析及排采动态测试资料,对影响煤储层完井品质的煤体结构指数、煤岩脆性指数、地应力差异系数进行了计算,并构建了煤储层完井品质指数预测模型;详细分析了煤层气排采出水量与各影响因素间的内在关系,建立了煤层气排采出水量预测模型;有机融合煤储层完井品质指数和出水量预测指数,建立了煤层气开采性评价指数预测模型和划分标准,进而基于该套技术方法进行了煤层气开采性评价。研究结果表明:本文所述技术既充分考虑了完井品质对煤层气开采的影响,又兼顾了排采出水量,所评价的煤层气可采性与煤层气开采实际生产情况较为吻合。

关键词：煤层气可采性测井资料评价

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