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Microstructure of TiB Whisker Reinforced Ti matrix Composite

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journal of materials Science & Technology 1997年第1期13卷 41-44页

作者： Lu, YX Li, DX Ping, DH Bi, j ma, ZY Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The composite of Ti matrix with TiB whisker reinforcement has been successfully fabricated. The content of TiB whisker in Ti matrix can reach about 30 vol. pet. Metallographic examination, morphology and microstructure of TiB whisker, interface structure between TiB whisker and Ti matrix were investigated using optical microscope, SEM, TEM and HREM technology. The diameter distribution of TiB whisker is from 0.1 mu m to 3.5 mu m and the aspect ratio of TiB whisker is from 10 to 20. The cross-section of whisker is generally polygon. Because of good compatibility between TiB whisker and Ti matrix it is identified that there is no obvious interaction of Ti matrix with TiB reinforcement and TiB whisker reinforced Ti matrix composites have excellent elevated properties.

关键词： Fiber reinforced materials

Effect of arc sprayed coatings on tensile properties of a type 316 steel

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中国有色金属学会会刊：英文版 2004年第z1期14卷 95-99页

作者： LIU Gui-min ma Li-li K.j.Kurzydlowski Faculty of materials Science and Engineering Academy of Armored Force EngineeringBeijing 100072 China Faculty of Materials Science and Engineering Academy of Armored Force EngineeringBeijing 100072 China Faculty of Materials Science and Engineering Warsaw University of Technology Warsaw Poland

The effect of Al- and AlSiRE-coatings obtained by arc spray (AS) and high velocity arc spray (HVAS) technologies, on the tensile properties of type 316 steel specimens strained at elevated temperatures in air and vacuum has been systematically investigated. It is found that both temperature and environment play an important role in determining the mechanical properties of the coated 316 steel specimens strained at elevated temperatures. And the quantitative changes of surface roughness of coatings before and after straining correspond to the mechanical properties of the 316 steel substrate.

关键词： type 316 steel arc spray high velocity arc spray coating tensile property

The joint Control of Variable Speed and On-Ramp Metering for Urban Expressway

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journal of Systems Engineering and Electronics 2001年第3期12卷 25-30页

作者： ma, j. Liu, X. Rong, j. Li, Z. Transportation Research Center Beijing Polytechnic University Beijing 100022 China

The traffic performance of urban expressway is subject to non-recurring and recurring events, which may cause heavy congestion and vehicles long queuing on ramps. The low performance may bring more traffic delay to the whole network of urban road. This paper presents a new method, the joint control of variable speed control and on-ramp metering, which attempts to improve the level of traffic operations on urban expressway. By analyzing traffic flow on urban expressway, an optimum control strategy of variable speed and on-ramp metering is established in the paper.

关键词： Function evaluation Highway traffic control Intelligent control mathematical models Motor transportation Parameter estimation Ramp generators Speed control

A NOVEL THEORY OF EFFECTIVE MECHANICAL PROPERTIES OF CLOSED-CELL FOAM maTERIALS

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Acta Mechanica Solida Sinica 2013年第6期26卷 559-569页

作者： Yuli ma Xianyue Su R.Pyrz j.Ch.Rauhe The State Key Laboratory for Turbulence and Complex Systems (LTCS) and Department of Mechanics and Aerospace Engineering College of EngineeringPeking University Chinalco Research Institute of Science and Technology Department of Mechanical and manufacturing Engineering Aalborg University

In this paper a new theory of effective mechanical properties of foam materials is proposed. A cell volume distribution coefficient is introduced to modify the original Gibson-Ashby equations of effective mechanical properties of foam materials. The constants that influence the effective modulus are replaced by the coeff^cient. Based on the modified distribution coefficient, the yield stress is also recalculated. Using X-ray microtomography, the internal structures of dif- ferent samples of polypropylene-nanoclay foam are obtained. The cell volume distributions of these samples are derived from the experiment by image analysis and the fitting curves are plot- ted. The distribution coefficient is acquired using the parameters from the theoretical model of the distribution curves. The results of the improved theory are compared with the experimental values and show good fitting quality. It was found that the precision of the improved theory is high and the cell volume distribution has an impact on the effective mechanical properties that would lead to the optimization of the synthesis procedure.

关键词： closed-cell foam cell volume distribution distribution coefficient Young's modulus yield stress distribution function

Effects of Solution Temperature on Tensile Properties ofSiC_w/2024Al Composite

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journal of materials Science & Technology 1995年第4期11卷 291-294页

作者： ma, ZY LU, YX LUO, M BI, j ZHANG, YZ NE UNIV TECHNOL SHENYANG 110006PEOPLES R CHINA

The effects of solution (quench) temperature on the properties of SiCW/Al composite have been investigated using tensile tests. The experiments indicate that the solution temperature of the composite fabricated by P/M technique can be raised to 560 degrees C. The tensile strength of the composite is obviously dependent on solution (quench) temperature and the composite solutionized at 540 degrees C exhibits a maximum of tensile strength and elongation-to-failure. These results can be accounted for by the variation of the dislocation density in the composite.

关键词： Metallic matrix composites

A Singular Linear Quadratic Time-Inconsistent Optimal Control Problem

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journal of Systems Science & Complexity 2023年第3期36卷 1024-1052页

作者： ma Bowen School of mathematics Sichuan UniversityChengdu 610064China

Yong j [Acta math. Appl. Sin. Engl. Ser. 28(2012), 1–30] [math. Control Relat. Fields1(2011), 83–118] studied a standard linear quadratic time-inconsistent optimal control problem via a cooperative and non-cooperative approach, respectively. The authors extend his results to a singular case. To handle the singularity, the authors prove the solvability of a generalized Riccati equation,and introduce a notion of MP-convergence of matrix. It is shown that the authors can obtain a family of parameter equilibrium controls in both cases. Another interesting outcome is that a new type of parameter forward-backward Volterra integral equations is derived.

关键词： Equilibrium control -person differential game singular LQ problem time-inconsistency

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面向航拍路面裂缝检测的AC-YOLO

计算机工程与应用 2025年第1期61卷 153-164页

作者：白锋马庆禄赵敏重庆交通大学土木工程学院重庆400074 重庆交通大学交通运输学院重庆400074 重庆大学自动化学院重庆400044

针对当前道路巡检智能化程度不足以及效率低等现状,为提高利用无人机道路巡检检测效率与检测精度,在YOLOv8s的基础上针对无人机航拍场景提出改进模型AC-YOLO,在主干网络引入动态大卷积核注意机制LSK-attention来扩展模型的感受野,提高... 详细信息

针对当前道路巡检智能化程度不足以及效率低等现状,为提高利用无人机道路巡检检测效率与检测精度,在YOLOv8s的基础上针对无人机航拍场景提出改进模型AC-YOLO,在主干网络引入动态大卷积核注意机制LSK-attention来扩展模型的感受野,提高对路面裂缝范围检测的准确性。在颈部结构设计多尺度特征融合策略,融入BiFPN网络,改善对细小裂缝的检测。替换损失函数为WIoUv3,优化梯度分配策略,使模型更加关注裂缝主体。在数据集UAV-PDD2023上进行实验验证,改进后AC-YOLO精准度达到0.895,较原模型提高0.128,maP50达到0.791,提高0.071,F1得分提高0.051,模型大小减小8.5%,FPS达到了129,提高4%。同时采用不同任务验证了模型泛化性能,实验结果证明AC-YOLO具有更强的检测性能,能有效应用于无人机视角下的路面裂缝检测。

关键词：道路巡检裂缝检测航拍裂缝增强感知特征融合

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Universal insertion of molecules in ionic compounds under pressure

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National Science Review 2024年第1期11卷 120-128页

作者： Feng Peng Yanming ma Chris j.Pickard Hanyu Liu maosheng Miao College of Physics and Electronic Information Luoyang Normal University Department of Chemistry and Biochemistry California State University Northridge State Key Laboratory of Superhard materials & Key Laboratory of material Simulation Methods and Software of Ministry of Education College of Physics Jilin University International Center of Future Science Jilin University Department of materials Science & Metallurgy University of Cambridge Advanced Institute for materials Research Tohoku University Department of Earth Science University of California Santa Barbara

Using first-principles calculations and crystal structure search methods, we found that many covalently bonded molecules such as H2, N2, CO2, NH3, H2O and CH4may react with NaC l, a prototype ionic solid,and form stable compounds under pressure while retaining their molecular structure. These molecules,despite whether they are homonuclear or heteronuclear, polar or non-polar, small or large, do not show strong chemical interactions with surrounding Na and Cl ions. In contrast, the most stable molecule among all examples, N2, is found to transform into cyclo-N5-anions while reacting with NaC l under high pressures. It provides a new route to synthesize pentazolates, which are promising green energy materials with high energy density. Our work demonstrates a unique and universal hybridization propensity of covalently bonded molecules and solid compounds under pressure. This surprising miscibility suggests possible mixing regions between the molecular and rock layers in the interiors of large planets.

关键词： molecule-solid hybrid materials high-pressure crystal structure prediction density functional theory planet interior

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用于水下图像增强的多层级联融合增强网络

电光与控制 2025年第1期32卷 68-73页

作者：王炫钧邵菲马彦卿西安建筑科技大学理学院西安710000

为了提高水下无人潜航器决策的准确性,构建了一种用于增强水下图像的多层级联融合增强网络。首先,设计注意力引导的色彩增强模块并结合多层级联增强架构,在提取图像多尺度特征的同时,加强特征重用;其次,设计全局调整模块,将Swin Transfo... 详细信息

为了提高水下无人潜航器决策的准确性,构建了一种用于增强水下图像的多层级联融合增强网络。首先,设计注意力引导的色彩增强模块并结合多层级联增强架构,在提取图像多尺度特征的同时,加强特征重用;其次,设计全局调整模块,将Swin Transformer与扩张卷积相结合,提升网络对于退化图像整体增强效果;最后,将各模块提取到的特征信息经由三重特征聚合模块进行融合增强,得到增强水下图像。为了可以更好地训练模型,构造了联合损失函数。与其他水下图像增强方法的对比实验结果表明,所提方法对于水下图像存在的色偏、模糊等问题均有着良好的增强效果,并对后续特征提取任务的完成有着较大的促进作用。

关键词：水下无人潜航器水下图像增强多层级联增强架构全局调整三重特征聚合

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