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Exfoliation corrosion of extruded Mg-Li-Ca alloy

Journal of Materials Science & Technology 2018年第9期34卷 1550-1557页

作者： zi-you ding Lan-Yue Cui Rong-Chang Zeng Yan-Bin Zhao Shao-Kang Guan Dao-Kui Xu Cun-Guo Lin College of Materials Science and Engineering Shandong University of Science and Technology Qingdao 266590 China School of Materials Science and Engineering Zhengzhou University Zhengzhou 450002 China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Science and Technology on Marine Corrosion and Protection Laboratory Qingdao 266071 China Qingdao Branch of Luoyang Ship Material Research Institute Qingdao 266101 China

Exfoliation on as-extruded Mg-1 Li-1 Ca magnesium alloy was investigated after an immersion in 3.5 wt%NaCl aqueous solution for 90, 120 and 150 days through optical microscope, digital camera, scanning electron microscope, electrochemical workstation, scanning Kalvin probe, X-ray diffraction and Fourier transform infrared spectroscope. The results demonstrated that exfoliation corrosion occurred on extruded Mg-1 Li-1 Ca alloy due to elongated microstructure parallel to surface, and delamination of lamellar structure resulted from galvanic effect and wedge effect. Skin layer with fine grains exhibited better corrosion resistance, whereas the interior with coarse grains and the intermetallic compound,Mg2 Ca particles existing in a fibrous structure, dispersed along grain boundaries and extrusion direction in a line. Furthermore, galvanic effect between Mg2 Ca particles and their neighboring a-Mg matrix facilitated dissolution of Mg2 Ca particles and a-Mg matrix; wedge effect was caused by formation of corrosion products. Exfoliation corrosion of extruded Mg-Li-Ca alloys might be a synergic effect of pitting corrosion,filiform corrosion, intergranular corrosion and stress corrosion. Finally, exfoliation corrosion mechanism was proposed.

关键词： Magnesium-lithium alloy Exfoliation corrosion Intermetallic compound Extrusion Microstructure

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Exfoliation Corrosion of As‑Extruded Mg–1Li–1Ca:the Influence of the Superficial Layer

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Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1339-1353页

作者： Ze‑Song Wei zi‑you ding Lei Cai Shao‑Xia Ma Dong‑Qing Zhao Lan‑Yue Cui Cheng‑Bao Liu Yuan‑Sheng Yang Yuan‑ding Huang Rong‑Chang Zeng Corrosion Laboratory for Light Metals College of Materials Science and EngineeringShandong University of Science and TechnologyQingdao 266590China Engineering Research Center for Magnesium‑Based New Materials Center for Advancing Materials Performance from the Nanoscale(CAMP‑Nano)State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials Advanced Materials InstituteQilu University of Technology(Shandong Academy of Sciences)Jinan 250014China Institute of Metals Research Chinese Academy of SciencesShenyang 110016China Institute of Metallic Biomaterials Helmholtz-Zentrum HereonMax‑Planck‑Str.121502 GeesthachtGermany

Exfoliation corrosion(EFC)has rarely been reported for wrought magnesium *** EFC of the as-extruded Mg–1Li–1Ca alloy was observed after the removal of outermost fine-grained *** microstructure and corrosion products were investigated using optical microscopy,scanning electron microscopy,electron backscattered diffraction,X-ray diffraction,and Fourier transform infrared *** corrosion behavior was analyzed using electrochemical polarization,electrochemical impedance spectroscopy,and scanning Kelvin probe *** results indicated that the surface of Mg–1Li–1Ca,with the superficial layer removed,was more susceptible to EFC.A linear correlation between grain boundary density and corrosion resistance was ***,the influence of factors such as grain size,intermetallic compounds,different alloy surfaces,and corrosion products on EFC were discussed,and the corresponding EFC mechanism was clarified.

关键词： Magnesium alloys Exfoliation corrosion Microstructure Intermetallic compound Metamorphic skin

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Effect of AlN coating on hydrogen permeability and surface structure of VT6 alloy by vacuum arc ion plating

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Chinese Physics B 2019年第10期28卷 546-549页

作者： zi-Yi ding National Research Tomsk Polytechnic University

We study the absorption of hydrogen of metal by the permeability method. With the help of the gas reaction controller(GRC), the absorptive capacity of hydrogen, which is a function of time, temperature and pressure, can be recorded. The effect of the performance of the hydrogen permeability of AlN coating on the titanium alloy surface structure is *** the research, the AlN is selected to be added to the titanium alloy sample VT6, and the properties of the titanium alloy are investigated, and the hydrogen absorption rate of the coating is calculated by performing the hydrogen saturation of the test sample. The results show that under 600℃ the AlN film reduces the hydrogen absorption rate of titanium alloy and improves the surface properties of VT6 alloy.

关键词： titanium alloy ion plating aluminum nitride hydrogen

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Gait Analysis of Quadruped Robot Using the Equivalent Mechanism Concept Based on Metamorphosis

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Chinese Journal of Mechanical Engineering 2019年第1期32卷 31-41页

作者： Kun Xu Peijin zi Xilun ding Robotics Institute School of Mechanical Engineering & Automation Beihang University

The previous research regarding the gait planning of quadruped robot focuses on the sequence for lifting o and placing the feet, but neglects the influence of body height. However, body height a ects gait performance significantly, such as in terms of the stride length and stability margin. We herein study the performance of a quadruped robot using the equivalent mechanism concept based on metamorphosis. Assuming the constraints between standing feet and the ground with hinges, the ground, standing legs and robot body are considered as a parallel mechanism, and each swing leg is regarded as a typical serial manipulator. The equivalent mechanism varies while the robot moves on the ground. One gait cycle is divided into several periods, including step forward stages and switching stages. There exists a specific equivalent mechanism corresponding to each gait period. The robot's locomotion can be regarded as the motion of these series of equivalent mechanisms. The kinematics model and simplified model of the equivalent mechanism is established. A new definition of the multilegged robot stability margin, based on friction coe cient, is presented to evaluate the robot stability. The stable workspaces of the equivalent mechanism in the step forward stage of trotting gait under di erent friction coe cients are analyzed. The stride length of the robots is presented by analyzing the relationship between the stable workspaces of the equivalent mechanisms of two adjacent step forward stages in one gait cycle. The simulation results show that the stride length is larger with increasing friction coe cient. We herein propose a new method based on metamorphosis, and an equivalent mechanism to analyze the stability margin and stable workspace of the multilegged robot.

关键词： Quadruped robot Gait transference Metamorphosis Metamorphic mechanism Stability Stride length

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Learning from biological attachment devices:applications of bioinspired reversible adhesive methods in robotics

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Frontiers of Mechanical Engineering 2022年第3期17卷 1-33页

作者： Kun XU Peijin zi Xilun ding School of Mechanical Engineering and Automation Beihang UniversityBeijing100191China

Many organisms have attachment organs with excellent functions,such as adhesion,clinging,and grasping,as a result of biological evolution to adapt to complex living *** nanoscale to macroscale,each type of adhesive organ has its own underlying *** biological adhesive mechanisms have been studied and can be incorporated into robot *** paper presents a systematic review of reversible biological adhesive methods and the bioinspired attachment devices that can be used in *** study discussed how biological adhesive methods,such as dry adhesion,wet adhesion,mechanical adhesion,and sub-ambient pressure adhesion,progress in *** morphology of typical adhesive organs,as well as the corresponding attachment models,is *** current state of bioinspired attachment device design and fabrication is ***,the design principles of attachment devices are summarized in this *** following section provides a systematic overview of climbing robots with bioinspired attachment ***,the current challenges and opportunities in bioinspired attachment research in robotics are discussed.

关键词： adhesion bioinspired attachment biomimetic gripper climbing robot

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A generalization of Banach's lemma and its applications to perturbations of bounded linear operators

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 363-369页

作者： WANG zi ding Jiu WANG Yu-wen School of Mathematics Sciences Harbin Normal UniversityHarbin 150025China School of Mathematics and Natural Sciences The University of Southern MississippiHattiesburg MS 39406-5043USA Academic Committee Harbin Institute of PetroleumHarbin 150027China

Let X be a Banach space and let P:X→X be a bounded linear *** an algebraic inequality on the spectrum of P,we give a new sufficient condition that guarantees the existence of(I-P)^(-1) as a bounded linear operator on X,and a bound on its spectral radius is also *** generalizes the classic Banach *** apply the result to the perturbation analysis of general bounded linear operators on X with commutative perturbations.

关键词： Banach lemma spectral radius generalized inverse perturbation analysis

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Holographic Schwinger effect in a soft wall AdS/QCD model

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Chinese Physics C 2021年第1期45卷 127-132页

作者： Yue ding zi-qiang Zhang School of Mathematics and Physics China University of GeosciencesWuhan 430074China

We perform a potential analysis for the holographic Schwinger effect in a deformed AdS5 model with conformal invariance broken by a background *** evaluated the static potential by analyzing the classical action of a string attached to a rectangular Wilson loop on a probe D3 brane located at an intermediate position in the bulk AdS *** observed that the inclusion of the chemical potential tends to enhance the production rate,which is opposite to the effect of the confining *** addition,we calculated the critical electric field based on the Dirac-Born-Infeld(DBI)action.

关键词： AdS/CFT correspondence gauge-gravity duality holographic Schwinger effect

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Quantum simulation of molecular interaction and dynamics at surfaces

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Frontiers of physics 2011年第3期6卷 294-308页

作者： zi-jing ding Yang JIAO Sheng MENG Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China

The interaction between molecules and solid surfaces plays important roles in various applications, including catalysis, sensors, nanoelectronies, and solar cells. Surprisingly, a full understanding of molecule-surface interaction at the quantum mechanical level has not been achieved even for very simple molecules, such as water. In this mini-review, we report recent progresses and current status of studies on interaction between representative molecules and surfaces. Taking water/metal, DNA bases/carbon nanotube, and organic dye molecule/oxide as examples, we focus on the understanding on the microstructure, electronic property, and electron-ion dynamics involved in these systems obtained from first-principles quantum mechanical calculations. We find that a quantum mechanical description of molecule surface interaction is essential for understanding interface phenomenon at the microscopic level, such as wetting. New theoretical developments, including van der Waals density functional and quantum nuclei treatment, improve further our understanding of surface interactions.

关键词： adsorption quantum simulation density functional theory electronic structure electrondynamics

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Effect of Preparation Methods of Bi_(2)O_(3) Nanoparticles on their Photocatalytic Activity

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Chemical Research in Chinese Universities 2004年第6期20卷 717-721页

作者： ding Peng DU Yao-guo XU zi-li Department of Environment Science College of Environment and ResourcesJilin UniversityChangchun 130023P.R.China Department of Chemistry Changchun Normal CollegeChangchun 130032P.R.China

Bi 2O 3 nanoparticles were prepared by means of ammonia precipitation, polyol mediated methods and microemulsion chemical method. The structure and properties of the as-prepared nanoparticles, having been submitted to a heat-treatment test at 750 ℃, were characterized by means of XRD, BET, XPS and UV-Vis absorption techniques. The photocatalytic oxidation reactions of benzene, toluene and xylene were used as the model reaction to measure the photocatalytic activity of Bi 2O 3 nanoparticles, respectively. The results show that the crystallite size of Bi 2O 3 prepared with different methods and calcined at 750 ℃ were 50.6, 38.5 and 31.5 nm, respectively. The photocatalytic activity of Bi 2O 3 nanoparticles prepared with the microemulsion chemical method was higher than that of the particles prepared with the polyol mediated method; and that of the particles prepared with the micromulsion chemical method was the highest among the three. The degradation rates of the three pollutants xylene, toluene and benzene decreased in sequence.

关键词： Bi_(2)O_(3) Preparation method Characterization Photocatalytic activity

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Mechanisms of Rhenium on Wettability and Interactions Between Nickel-Base Superalloy Melt and Al2O3-Based Ceramic Material

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Acta Metallurgica Sinica(English Letters) 2020年第7期33卷 1021-1030页

作者： Yun zi Jie Meng Chaowei Zhang Yizhou Zhou Yutian ding Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Department of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China

A systematic study on the wettability and interactions between superalloy melts with various Re contents and Al2 O3-based ceramic moulds was presented in this *** was found that the increase of Re content inhibited the interfacial reactions to some *** regard to the 0,1.5 and 3 Re alloys,a double reaction layer containing Al2 O3 and HfO2 was formed at the interface,but the thickness of reaction layer decreased with the increase of Re ***,only Al2 O3 phase was detected at the interface when the content of Re was 6 wt%,and the interface reaction was the weakest and the thickness of reaction layer was the *** wetting angle of the alloy/ceramic system increased as the level of Re ***,the formation of viscous sand at the interface mainly depended on the change of wetting angle of the system.

关键词： superalloy alloy alloys

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