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基于状态空间模型的激光再制造熔池温度控制系统

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表面工程与再制造 2024年第2期24卷 50-50页

作者： Yang G.-Z. Liu T.-M. Song B.-x. Jiang x.-Y. Wang Z.-S. Chen K.-Q. Liu W.-J. School of Mechanical Engineering Shenyang University of Technology Shenyang China

激光再制造是用于再制造的一项重要技术,在航空航天、冶金、能源等领域应用广泛。然而,形状控制问题一直是制约其规模化和工业化应用的瓶颈。在激光再制造过程中,熔池温度是决定再制造件形状和性能稳定性的关键。基于此,本文提出了一种... 详细信息

激光再制造是用于再制造的一项重要技术,在航空航天、冶金、能源等领域应用广泛。然而,形状控制问题一直是制约其规模化和工业化应用的瓶颈。在激光再制造过程中,熔池温度是决定再制造件形状和性能稳定性的关键。基于此,本文提出了一种基于状态空间模型的激光再制造熔池温度实时在线控制方法,解决了控制机理模型难以建立和多变量约束的问题。

关键词：状态空间模型激光再制造熔池温度航空航天形状控制控制系统变量约束性能稳定性

Deformation kinking and highly localized nanocrystallization in metastableβ-Ti alloys using cold forging

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Journal of Materials Science & Technology 2022年第25期120卷 53-64页

作者： Keer Li W.Chen G.x.Yu J.Y.Zhang S.W.xin J.x.Liu x.x.Wang J.Sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China Northwest Institute for Nonferrous Metal research Xi’an 710016China Baoji Titanium Industry Co. Ltd.Baoji 721014China

Deformation kinking as an uncommon plastic deformation mechanism has been reported in several materials while the relevant microstructure evolution and grain refinement behavior at a large strain remain unclear so *** this study,the issue was systematically investigated by utilizing cold forging to impose severe plastic deformation(SPD)on Ti-11 V metastableβ-Ti *** is found that the formation of kink bands experiences dislocation gliding,pre-kinking and the ripening of pre-kinks in *** kink bands are subsequently thickened through the coalescence of multiple kink bands in a manner of high *** dislocation slip is developed as a dominant deformation mechanism when deformation kinking is *** resulting grain refinement involves transverse breakdown and longitudinal splitting of dislocation walls and cells,which fragment kink bands into smallβ-*** refinement of theβ-blocks is still governed by dislocation activities,and finally nanograins with a diameter of~15 nm are produced at a large strain of ***,it is revealed that nanocrystallization is highly localized inside kink bands while the outer microstructure maintains original coarse *** localized refinement characterization is ascribed to the intrinsic soft nature of kink bands,shown as low hardness in nanoindentation *** intrinsic softening of kink bands is uncovered to originate from the inner degraded dislocation density evidenced by both experimental measurement and theoretical *** findings enrich fundamental understanding of deformation kinking,and shed some light on exploring the deformation accommodation mechanisms for metal materials at large strains.

关键词： Metastableβ-Ti alloys Deformation kinking Microstructural evolution Grain refinement Dislocations

Oscillation in the KMnO₄-NH₂CH₂COOH CSTr System

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Chinese Chemical Letters 1996年第10期7卷 928-930页

作者： Li H.x. Huang x.J. Department of Chemistty Shanghai Normal University Shanghai 200234

The chemical oscillating reactions in KMnO4-NH2CH2COOH-H3PO CSTr system in the presence and absence of Ag+ have been *** reaction conditions and phase diagrams have been determined. Some effects on the oscillation have then studied. The stabilization of colloidal particles of MnO2 by PO43-has been investigated. The roles of Ag+ in the above reactions have also been studied.

关键词： CH NH Oscillation in the KMnO4-NH2CH2COOH CSTr System CSTr

Observation and Simulation of n=1 reversed Shear Alfvén Eigenmode on the HL-2A Tokamak

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Chinese Physics Letters 2022年第10期39卷 26-33页

作者： P.W.Shi Y.r.Yang W.Chen Z.B.Shi Z.C.Yang L.M.Yu T.B.Wang x.x.He x.Q.Ji W.L.Zhong M.xu x.r.Duan Southwestern Institute of Physics Chengdu 610041China State Key Laboratory of Intense Pulsed radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

A branch of high-frequency Alfvenic modes is observed on the HL-2A *** electromagnetic mode can be driven unstably in the plasma with an off-axis neutral beam *** mode frequency keeps almost unchanged or presents a slow-sweeping behavior,depending on the detail current *** poloidal and toroidal mode numbers are𝑚m/n=1/*** mode has a quite short duration(≤20 ms)and usually appears 5-10 ms after the neutral beam being injected into the *** simulations based on M3D-K have also been carried *** result suggests that co-passing energetic particles are responsible for the mode *** simulated mode structures are localized nearby location of minimum safety factor(q_(min))and agree with the structures obtained through tomography of soft x-ray ***,the modes are localized in the continuum gap and their frequencies increase with variation of𝑞min in a wide *** but not least,the characteristic of unchanged frequency on experiment is also reproduced by the nonlinear simulation with a fixed safety *** those evidences indicate that the𝑛n=1 high-frequency mode may belong to a reversed shear Alfven eigenmode.

关键词： Alfven mode unchanged

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青藏高原冰尘微生物对有机质的潜在转化过程

中国科学：地球科学 2024年第6期54卷 2008-2019页

作者：郭泌汐刘勇勤钟旭史权何晨郑强蔡阮鸿青藏高原地球系统与资源环境重点实验室中国科学院青藏高原研究所北京100101 兰州大学泛第三极环境中心兰州730000 Department of Earth Oceanand Atmospheric SciencesUniversity of British ColumbiaVancouverBC V6T 1Z4Canada 中国石油大学重质油国家重点实验室北京102249 厦门大学近海海洋环境科学国家重点实验室厦门361102 厦门大学福建省海洋碳汇重点实验室厦门361005

微生物在冰川碳循环中发挥着重要作用,然而当前缺乏对冰尘微生物参与的溶解性有机质(DOM)转化过程的深入研究.本研究利用了分析化学和微生物生态学的主流手段——超高分辨率的傅里叶变换离子回旋共振质谱(FT-ICr MS)和微生物16S rrNA测... 详细信息

微生物在冰川碳循环中发挥着重要作用,然而当前缺乏对冰尘微生物参与的溶解性有机质(DOM)转化过程的深入研究.本研究利用了分析化学和微生物生态学的主流手段——超高分辨率的傅里叶变换离子回旋共振质谱(FT-ICr MS)和微生物16S rrNA测序技术,分别解析了培养实验中青藏高原龙匣宰陇巴冰川冰尘的DOM分子组成以及微生物群落,并耦联两者构建了复杂微生物参与的冰川DOM转化过程.研究结果表明:在60天的培养实验中,冰尘DOM的生物可利用性随着培养时间的增加而降低,微生物对DOM组分的转化过程可分为三个阶段.在前7天里,微生物选择性降解了具有较高H/Cwa和较低O/Cwa的DOM分子,且群落变化不大;在第15至30天期间,DOM组分保持稳定,但微生物多样性增加;到培养末期, DOM分子在微生物作用下转化为难降解的惰性DOM组分,这些惰性DOM具有更高的芳香指数和O/Cwa、更低的H/Cwa以及含有更多的杂原子.此外,培养实验揭示了冰尘中Cyanobacteria、Bacteroidota、Gammaproteobacteria、Firmicutes和Actinobacteriota等类群协同作用于DOM组分转化,使其变得惰性.本研究揭示了冰尘中微生物转化DOM组分的过程,为理解微生物在冰川有机碳循环中的作用提供了新见解.

关键词：冰尘溶解性有机质微生物降解微生物群落时间变化

THE ADAPTIVE FINITE ELEMENT rEMESHING IN LArGE DEFOrMATION OF METAL FOrMING

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Acta Metallurgica Sinica(English Letters) 2004年第3期17卷 323-326页

作者： x.x.Guo J.S.Liu Advanced Manufacturing Technology and Engineering Department Shenzhen Polytechnic Shenzhen 518055ChinaSchool of Material Science and Engineering Taiyuan Heavy Machinery Institute Taiyuan 030024 China

The adaptive remeshing technique for quadrilateral elements consists of modules thetrigger of remeshing, the new mesh generation, adaptive refinement and interpolationof field variables. The new adaptive mesh genemtion is the key problem. First, acoarse mesh is created by using 'loop algorithm'. Subsequent local mesh adaptiverefinement is performed based on effective strain. Finally, a typical example of upset-ting is given to test efficient of techniques, from which it is verified that the remeshingalgorithm developed here exhibits good performance and has high accuracy.

关键词： adaptive remeshing quadrilateral elements metal forming

Giant Magneto-impedance Effect in Composite Wires with Different Core Layer

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Nano-Micro Letters 2013年第2期5卷 140-144页

作者： r.L.Wang x.Li x.H.Kong Y.x.Guo J.Z.ruan Z.J.Zhao Department of Physics Engineering Research Center for Nanophotonics & Advanced Instrument Ministry of Education East China Normal University Experimental Teaching Center of Physics Shanghai Ocean University

Composite structure materials were potential sensing elements for magnetic sensors due to Giant magnetoimpedance(GMI) effect. Two kinds of composite wires with different magnetic/non-magnetic structures were fabricated by using electroless deposition methods and the magnetoimpedance properties were investigated. The maximum GMI ratio of 114% was acquired at 60 MHz in the composite wires with a ferromagnetic core, whereas, 116% of maximum GMI ratio was found in the composite wires with a conductive core at low frequency of 600 k Hz. These results exhibit that the GMI ratio reaches the maximum when magnetoresistance ratio ?r/r and magnetoinductance ratio ?x/x make the comparative contributions to the total magnetoimpedance(MI). The obvious GMI effect obtained in the composite wires with conductive core frequency may provide a candidate for applications in magnetic sensors, especially at low frequencies.

关键词： Composite wires Electroless deposition Giant Magnetoimpedance effect resistivity

Machine Learning‑Based Detection of Graphene Defects with Atomic Precision

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Nano-Micro Letters 2020年第12期12卷 331-343页

作者： Bowen Zheng Grace x.Gu Department of Mechanical Engineering University of CaliforniaBerkeleyCA 94720USA

Defects in graphene can profoundly impact its extraordinary properties,ultimately influencing the performances of graphene-based *** to detect defects with atomic resolution in graphene can be technically demanding and involve complex sample *** alternative approach is to observe the thermal vibration properties of the graphene sheet,which reflects defect information but in an implicit *** learning,an emerging data-driven approach that offers solutions to learning hidden patterns from complex data,has been extensively applied in material design and discovery *** this paper,we propose a machine learning-based approach to detect graphene defects by discovering the hidden correlation between defect locations and thermal vibration *** prediction strategies are developed:an atom-based method which constructs data by atom indices,and a domain-based method which constructs data by domain *** show that while the atom-based method is capable of detecting a single-atom vacancy,the domain-based method can detect an unknown number of multiple vacancies up to atomic *** methods can achieve approximately a 90%prediction accuracy on the reserved data for testing,indicating a promising extrapolation into unseen future graphene *** proposed strategy offers promising solutions for the non-destructive evaluation of nanomaterials and accelerates new material discoveries.

关键词： Machine learning Graphene Defects Molecular dynamics Nanomaterials

Survey of the mechanisms of power take-off(PTO)devices of wave energy converters

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Acta Mechanica Sinica 2020年第3期36卷 644-658页

作者： Z.Liu r.Zhang H.xiao x.Wang School of Engineering RMIT UniversityBundooraVIC 3083Australia

Ocean wave energy conversion as one of the renewable clean energy sources is attracting the research interests of many *** review introduces different types of power take-off(PTO)technology of wave energy *** novelty of this paper is to present advantages and disadvantages of the linear direct and indirect drive PTO devices for ocean wave energy *** designs and optimizations of PTO systems of ocean wave energy converters have been studied from reviewing the recently published *** novel mechanical designs of the PTO systems have been compared and investigated in order to increase the energy harvesting efficiency.

关键词： ocean wave energy