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SSRN 2024年

作者： Li, Wen Li, Shaojie Nan, Yang Bai, Xuepiao Li, Weiping School of Materials Science and Engineering Beihang University Beijing100191 China Aviation Key Laboratory of Science and Technology on Advanced Surface Engineering AVIC Manufacturing Technology Institute Beijing100024 China

T-shaped joints of high-strength aluminum alloy welded by friction stir welding (FSW) are expected to replace the traditional riveting structures. However, the corrosion of T-joint still hinder the popularization of FSW in aerospace industry. Herein, T-joints of 2A12 and 2A97 aluminum alloys are prepared and studied via structural characterization and corrosion tests. The microstructures and constituents of different micro zones in T-joints before and after corrosion tests are characterized and analyzed particularly. The internal relationship between different micro zones in T-joints and their corrosion behaviors are clarified, which provides theoretical basis for improving welding process and surface protection after welding. © 2024, The Authors. All rights reserved.

关键词： Friction stir welding

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Effect of Heat and Cryogenic Treatments on the Microstructure and Properties of Yf3 Modified Niti-Si Laser Cladding Coatings

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SSRN 2022年

作者： Su, Wennan Zhang, Chi Cui, Xiufang Jin, Guo Liu, Changhao Liu, Erbao Li, Jian Zhao, Haonan Cao, Boyu Tian, Haoliang Institute of Surface/Interface Science and Technology Key Laboratory of Superlight Material and Surface Technology Ministry of Education College of Material Science and Chemical Engineering Harbin Engineering University Harbin150001 China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Beijing Institute of Aeronautical Materials Beijing100095 China

YF 3 modification NiTi-Si coatings were prepared on Ti6Al4V substrate by laser cladding. On this foundation, heat and cryogenic treatments were conducted respectively to explore the effect of after-treatment procedures. The consequence of post-treatment methods on the phase constituent, microstructure, mechanical property, and phase transition characteristics of post-treatment coatings was studied. The phase constituent of the three coatings is roughly the same, composed of NiTi and NiTi 2 . Simultaneously, eutectic structures were found in three coatings, which also proved that the post-treatment would not affect the appearance of the eutectic structure. The results show that heat treatment led to the coarsening of the grain size of the NiTi phase, and the composition of Si element in the NiTi 2 phase increased. On the contrary, the cryogenic treatment led to the refinement of grains and eutectic structure in the coatings. In addition, due to the rapid cooling rate provided by cryogenic treatment, the spinodal decomposition of the Si element occurred in the NiTi 2 phase, which was confirmed by TEM and EDS. The microhardness of the three coatings is as follows: cryogenic treatment>original coatings>heat treatment. The cryogenic treatment coating has the highest microhardness due to grain refinement and spinodal decomposition. Furthermore, the post-treatments also affected the phase transformation characteristics of the coatings. © 2022, The Authors. All rights reserved.

关键词： Coatings

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Selective excitation of a three-dimensionally oriented single plasmonic dipole

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Photonics Research 2019年第6期7卷 693-698页

作者： FAJUN XIAO GUANGLIN WANG XUETAO GAN WUYUN SHANG SHIYIN CAO WEIREN ZHU TING MEI MALIN PREMARATNE JIANLIN ZHAO MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology School of Science Northwestern Polytechnical University Xi'an 710129 China Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China Advanced Computing and Simulation Laboratory (AXL) Department of Electrical and Computer Systems Engineering Monash University Clayton VIC 3800 Australia

We experimentally demonstrate a scheme to deterministically excite a three-dimensionally oriented electric dipole in a single Au nanosphere by using a tightly focused radially polarized beam whose focal field possesses polarization states along three-dimensional(3D) orientations owing to the spatial overlap between longitudinal and radial electric field components. Experiment observations indicate that the orientation of an excited dipole moment gradually changes from out-of-plane to in-plane when the nanosphere is moved away from the beam center, which is reconfirmed by full-wave simulations. Moreover, rigorous calculation based on Mie theory reveals that a reduced effective ambient permittivity accompanies the rotation of the dipole moment, leading to a blue-shifted and narrowed resonance peak. We envision that our results could find applications in detecting the 3D orientation of isolated molecules and benefit the fine manipulation of light–matter interactions at the single-molecule level.

关键词： Selective excitation plasmonic dipole

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Effects of High Al Content On the Phase Constituents and Thermal Properties in Nicocraly Alloys

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SSRN 2024年

作者： Zhang, Jin Nie, Zhihua Tan, Chengpeng Mu, Rende Li, Shilei Ning, Xianjin Tan, Chengwen School of Materials Science and Engineering Beijing Institute of Technology Beijing100081 China Co. Ltd. Suzhou215211 China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material AECC Beijing Institute of Aeronautical Materials Beijing100095 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China

MCrAlY (M = Ni and/or Co) metallic coatings are essential for the protection of hot-end components against thermal and corrosion damage. Increasing the Al content is considered a feasible solution to improve the high temperature performance of MCrAlY coatings. In this paper, the effects of high Al contents (12 – 20 wt.%) on the phase constituents and cast microstructures in MCrAlY alloys were studied by high-energy X-ray diffraction and electron microscopy techniques combined with phase equilibria calculations. High Al content improved the stability of β, σ, and α phases. Meanwhile, an evolution of cast microstructure morphology from dendrite structure to equiaxed grain structure was observed. The thermal properties were analyzed, which were closely related to the phase constituents and solid-to-solid phase transitions at evaluated temperatures. This work is instructive for developing high Al content MCrAlY coatings for next generation thermal barrier applications. © 2024, The Authors. All rights reserved.

关键词： Morphology

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Numerical simulation of materials-oriented ultra-precision diamond cutting:review and outlook

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International Journal of Extreme Manufacturing 2023年第2期5卷 1-21页

作者： Liang Zhao Junjie Zhang Jianguo Zhang Houfu Dai Alexander Hartmaier Tao Sun Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China School of Mechanical and Engineering Guizhou UniversityGuizhou 550025People’s Republic of China Interdisciplinary Centre for Advanced Materials Simulation Ruhr-University BochumBochum 44801Germany

Ultra-precision diamond cutting is a promising machining technique for realizing ultra-smooth surface of different kinds of *** fundamental understanding of the impact of workpiece material properties on cutting mechanisms is crucial for promoting the capability of the machining technique,numerical simulation methods at different length and time scales act as important supplements to experimental *** this work,we present a compact review on recent advancements in the numerical simulations of material-oriented diamond cutting,in which representative machining phenomena are systematically summarized and discussed by multiscale simulations such as molecular dynamics simulation and finite element simulation:the anisotropy cutting behavior of polycrystalline material,the thermo-mechanical coupling tool-chip friction states,the synergetic cutting responses of individual phase in composite materials,and the impact of various external energetic fields on cutting *** particular,the novel physics-based numerical models,which involve the high precision constitutive law associated with heterogeneous deformation behavior,the thermo-mechanical coupling algorithm associated with tool-chip friction,the configurations of individual phases in line with real microstructural characteristics of composite materials,and the integration of external energetic fields into cutting models,are ***,insights into the future development of advanced numerical simulation techniques for diamond cutting of advanced structured materials are also *** aspects reported in this review present guidelines for the numerical simulations of ultra-precision mechanical machining responses for a variety of materials.

关键词： diamond cutting ultra-smooth surface material-oriented physics-based simulation model molecular dynamics finite element

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Effects of High Al Contents on the Phase Constituents and Thermal Properties in Nicocraly Alloys

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SSRN 2024年

关键词： Morphology

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THE BOOSTED PROXIMAL DIFFERENCE-OF-CONVEX ALGORITHM

Journal of Applied and Numerical Optimization

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Journal of Applied and Numerical Optimization 2023年第2期5卷 255-269页

作者： Hu, Ziyue Dong, Qiao-Li Qin, Xiaolong Tianjin Key Laboratory for Advanced Signal Processing and College of Science Civil Aviation University of China Tianjin300300 China Center for Advanced Information Technology Kyung Hee University Seoul02447 Korea Republic of

In this paper, we propose a boosted proximal difference-of-convex algorithm for solving a minimization problem composed of the sum of a smooth convex function and a continuously differentiable convex function minus a continuous and strongly convex function. By adding an additional line search step, the convergence of proximal difference-of-convex algorithm is accelerated. We prove that any limit point of iterative sequence is a critical point of generalized difference-of-convex programming, and the corresponding objective value decreases monotonically and converges. By assuming that the objective function satisfies the strong Kurdyka-Lojasiewicz inequality, we prove the convergence of whole sequence of the proposed algorithm and give the convergence rate. The strong convexity of the convex part of the minimization problem in [F.J. Aragón Artacho, P.T. Vuong, The boosted difference of convex functions algorithm for nonsmooth functions, SIAM J. Optim. 30 (2020), 980-1006] is substituted by the Lipschitz continuity of the gradient of one convex function. Numerical experiments are given to demonstrate the performance of the proposed algorithm compared with the proximal difference-ofconvex algorithm. © 2023 Journal of Applied and Numerical Optimization.

关键词： Iterative methods

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Biodiversity conservation and ecological restoration of vulnerable ecosystems in the Anthropocene

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Journal of Plant Ecology 2024年第5期17卷 1-4页

作者： Zhonghua Ning Tian Xie Xinxin Wang Zhenchang Zhu Cong Chen Baoshan Cui Key Laboratory of Ecological Protection in the Yellow River Basin of National Forestry and Grassland Administration School of Ecology and Nature ConservationBeijing Forestry UniversityBeijing 100083China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing 100875China Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering National Observations and Research Station for Wetland Ecosystems of the Yangtze EstuarySchool of Life ScienceFudan UniversityShanghai 200433China School of Ecology Environment and ResourcesGuangdong University of TechnologyGuangzhou 510006China Research and Development Center for Watershed Environmental Eco-engineering Advanced Institute of Natural SciencesBeijing Normal UniversityZhuhai 519087China

This editorial summarizes the contributions to the Special Issue Biodiversity conservation and ecological restoration of vulnerable ecosystems in the Anthropocene',established under the Journal of Plant Ecology.

关键词： Biodiversity ecosystems restoration

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Numerical Fracture Analysis of a Reactor Pressure Vessel based on Abaqus-FRANC3D Co-simulation Method

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Procedia Structural Integrity 2022年 37卷 225-232页

作者： M. Annor-Nyarko Hong Xia Key Laboratory of Nuclear Safety and Advanced Nuclear Energy Technology Ministry of Industry and Information Technology Harbin Engineering University Harbin 150001 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin 150001 China Nuclear Installations Directorate Nuclear Regulatory Authority Ghana

The reactor pressure vessel (RPV) is subjected to many cyclic loadings critical of which is the integrity risk posed by pressurized thermal shock (PTS) loadings induced by one of the most frequent anticipated operational occurrences - inadvertent operation of the safety injection system (SIS). In this paper, the fracture mechanics analysis for an ageing pressurized water reactor subjected to PTS induced by inadvertent actuation of the SIS is performed using a proposed simplified Abaqus-FRANC3D co-simulation method. A three-dimensional (3-D) finite element half-symmetric model of a typical pressured water reactor RPV is used to perform thermal-mechanical stress coupling analysis. 3-D fracture mechanic submodel with an assumed surface crack is created for the computation of the transient integrity parameter-stress intensity factor (SIF), using M-integral approach coupled in the proposed co-simulation method. Subsequently ASME method is used to evaluate the vessel’s material fracture toughness. Finally, the SIFs obtained with the simplified co-simulation method is compared with the conventional virtual crack-closure technique (VCCT), and the result show good agreement. This work serves as a useful reference for fast crack propagation and life prediction analysis of ageing PWR RPVs.

关键词： Pressurized thermal shock Fracture mechanics Reactor pressure vessel Safety injection system Stress intensity factor FRANC3D

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Design and simulation of a Micromechanical Silicon Resonant Accelerometer with Low Temperature Sensitivity

Design and Simulation of a Micromechanical Silicon Resonant ...

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International Conference on Instrumentation, Measurement, Computer, Communication and Control (IMCCC)

作者： Yang Gao Hongsheng Li Libin Huang Songli Wang School of Instrument Science and Engineering Southeast University Nanjing China Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology Southeast University Ministry of Education Nanjing China Aviation Key Laboratory of Science and Technology on Inertia FACRI Xi'an China

ISBN: (数字)9781538682463

ISBN: (纸本)9781538682470

Because of the mismatch of material properties between silicon and glass, especially the mismatching thermal expansion coefficients, the Micromechanical Silicon Resonant Accelerometer based on the Deep Dry Silicon On Glass (DDSOG) technique is seriously affected by the temperature during the fabrication, packaging and use processes. Based on the working principle and temperature characteristics of Micromechanical Silicon Resonant Accelerometer, the effect of the mismatching thermal expansion coefficients of silicon and glass is analyzed, and a Single-Anchor-Supported accelerometer structure with low temperature sensitivity is designed. simulation results show that the structure can effectively reduce the effect of mismatching thermal expansion coefficients of silicon and glass.

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