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Microstructure and mechanical property of Mg-10Gd-2Y-1.5Zn-0.5Zr alloy processed by eight-pass equal-channel angular pressing

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Rare Metals 2023年第4期42卷 1371-1377页

作者： Huan liu Jia Ju Xiao-Wei Yang Yu-Hua Li Jing-Hua jiang ai-bin Ma College of Mechanics and Materials Hohai UniversityNanjing211100China Suqian Research Institute of Hohai University Suqian223800China College of Materials Engineering Nanjing Institute of TechnologyNanjing211167China

In this work,a high-strength Mg-10Gd-2Y-1.5Zn-0.5Zr(wt%)alloy was prepared via eight passes of equal-channel angular pressing(ECAP).The microstructures and mechanical properties of as-cast and ECAP alloys were systematically investigated by X-ray diffraction(XRD),optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and electronic universal testing *** obtained results indicate that the microstructure of as-cast alloy consists ofα-Mg dendrite,network Mg3(Gd,Y,Zn)phase and lamellar 14H long-period stacking ordered(LPSO)phase which is precipitated near the boundary of Mg3(Gd,Y,Zn)*** eight-pass ECAP,the network Mg3(Gd,Y,Zn)phase is deformed and ***,the refined Mg_3(Gd,Y,Zn)particles are not distributed uniformly in the matrix,but still aggregated at the interdendritic ***,the content of 14H lamellas increases obviously,and they become bent and kinked during severe *** is activated in the region between Mg3(Gd,Y,Zn)particles and 14H *** test at room temperature indicates that the ECAP alloy exhibits excellent mechanical property with compressive strength of 518 MPa and fracture strain of 21.6%.The comprehensive high strength and toughness could be ascribed to the refined Mg_3(Gd,Y,Zn)particles,DRX grains and kinked 14H LPSO phase.

关键词： Mg-Gd-Y-Zn-Zr Long-period stacking ordered phase Equal-channel angular pressing Compression strength Fracture strain

Axial Assembled Correspondence Network for Few-Shot Semantic Segmentation

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IEEE/CAA Journal of Automatica Sinica 2023年第3期10卷 711-721页

作者： Yu liu bin jiang Jiaming Xu School of Automation Science and Engineering South China University of TechnologyGuangzhou 510640 R&D Center of Precision Electronic Manufacturing Technology Guangzhou Institute of Modern Industrial Technologyand also with the High Performance Motor and Intelligent Control Engineering Technology Research Center of Guangdong ProvinceGuangzhou 511458China School of Automation Science and Engineering South China University of TechnologyGuangzhou 510640China IEEE

Few-shot semantic segmentation aims at training a model that can segment novel classes in a query image with only a few densely annotated support *** remains a challenge because of large intra-class variations between the support and query *** approaches utilize 4D convolutions to mine semantic correspondence between the support and query ***,they still suffer from heavy computation,sparse correspondence,and large *** propose axial assembled correspondence network(AACNet)to alleviate these *** key point of AACNet is the proposed axial assembled 4D kernel,which constructs the basic block for semantic correspondence encoder(SCE).Furthermore,we propose the deblurring equations to provide more robust correspondence for the aforementioned SCE and design a novel fusion module to mix correspondences in a learnable *** on PASCAL-5~i reveal that our AACNet achieves a mean intersection-over-union score of 65.9%for 1-shot segmentation and 70.6%for 5-shot segmentation,surpassing the state-of-the-art method by 5.8%and 5.0%respectively.

关键词： Artificial intelligence computer vision deep convolutional neural network few-shot semantic segmentation

Controlling Corrosion Resistance of a Biodegradable Mg–Y–Zn Alloy with LPSO Phases via Multi-pass ECAP Process

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1180-1190页

作者： Li-Sha Wang Jing-Hua jiang Bassiouny Saleh Qiu-Yuan XieQiong Xu Huan liu ai-bin Ma College of Mechanics and Materials Hohai UniversityNanjing 210098China Suqian Institute Hohai UniversitySuqian 223800China Production Engineering Department Alexandria UniversityAlexandria 21544Egypt

Mg-RE(rear earth) alloys with long period stacking(LPSO) structures have great potential in biomedical applications. The present work focused on the microstructure and corrosion behaviors of Mg 98.5 Y1 Zn0.5 alloys with 18 R LPSO structure after equal channel angular pressing(ECAP). The results showed that the ECAP process changed the grain size and the distribution of LPSO particles thus controlled the total corrosion rates of Mg 98.5 Y1 Zn0.5 alloys. During the ECAP process from 0 p to 12 p, the grain size reduced from 160–180 μm(as-cast) to 6–8 μm(12 p). The LPSO structures became kinked(4 p), then started to be broken into smaller pieces(8 p), and at last comminuted to fine particles and redistributed uniformly inside the matrix(12 p). The improvement in the corrosion resistance for ECAP samples was obtained from 0 p to 8 p, with the corrosion rate reduced from 3.24 mm/year(0 p) to 2.35 mm/year(8 p) in simulated body fluid, and the 12 p ECAP alloy exhibited the highest corrosion rate of 4.54 mm/year.

关键词： Corrosion behavior Long period stacking ordered phase Magnesium alloys Equal channel angular pressing(ECAP)process Biomaterials

Angel: a new large-scale machine learning system

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National Science Review 2018年第2期5卷 216-236页

作者： Jie jiang Lele Yu Jiawei jiang Yuhong liu bin Cui Key Lab of High Confidence Software Technologies (MOE) School of EECSPeking University

Machine Learning(ML) techniques now are ubiquitous tools to extract structural information from data collections. With the increasing volume of data, large-scale ML applications require an efficient implementation to accelerate the performance. Existing systems parallelize algorithms through either data parallelism or model parallelism. But data parallelism cannot obtain good statistical efficiency due to the conflicting updates to parameters while the performance is damaged by global barriers in model parallel methods. In this paper, we propose a new system, named Angel, to facilitate the development of large-scale ML applications in production environment. By allowing concurrent updates to model across different groups and scheduling the updates in each group, Angel can achieve a good balance between hardware efficiency and statistical efficiency. Besides, Angel reduces the network latency by overlapping the parameter pulling and update computing and also utilizes the sparseness of data to avoid the pulling of unnecessary parameters. We also enhance the usability of Angel by providing a set of efficient tools to integrate with application pipelines and provisioning efficient fault tolerance mechanisms. We conduct extensive experiments to demonstrate the superiority of Angel.

关键词： machine learning distributed system algorithms big data analytics

Fault Estimation and Accommodation for a Class of Nonlinear System Based on Neural Network Observer

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第2期35卷 318-325页

作者： Wang Ruonan jiang bin liu Jianwei College of Automation Engineering Nanjing University of Aeronautics and Astronautics

The problem of fault estimation and accommodation of nonlinear systems with disturbances is studied using adaptive observer and neural network techniques.A robust adaptive learning algorithm based on switchingβsmodification is developed to realize the accurate and fast estimation of unknown actuator faults or component *** a fault tolerant controller is designed to restore system *** error convergence and system stability can be guaranteed by Lyapunov stability ***,simulation results of quadrotor helicopter attitude systems are presented to illustrate the efficiency of the proposed techniques.

关键词： actuator fault component fault neural network adaptive observer fault tolerant controller

Preface——Special Issue on New Directions in Nonlinear and Distributed Control

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Journal of Systems Science & Complexity 2018年第1期31卷 1-3页

作者： liu Tengfei XIN bin jiang Zhong-Ping State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang 110819 China School of Automation State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology Beijing 100081 China Tandon School of Engineering New York University Brooklyn NY 11201 USA

Nonlinearity is ubiquitous in engineering and natural *** development of nonlinear control can be traced back to decades *** date,the research has reached the stage that emphasizes developing methodologies that can ha... 详细信息

关键词：控制问题非线性分布式工程应用程序电子物理自然系统生产线相互作用

On modeling approach for embedded real-time software simulation testing

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Journal of Systems Engineering and Electronics 2009年第2期20卷 420-426页

作者： Yin Yongfeng liu bin Zhong Deming jiang Tongmin Dept. of System Engineering of Engineering Technology Beihang Univ. Beijing 100191 P. R. China

Modeling technology has been introduced into software testing field. However, how to carry through the testing modeling effectively is still a difficulty. Based on combination of simulation modeling technology and embedded real-time software testing method, the process of simulation testing modeling is studied first. And then, the supporting environment of simulation testing modeling is put forward. Furthermore, an approach of embedded real-time software simulation testing modeling including modeling of cross-linked equipments of system under testing （SUT）, test case, testing scheduling, and testing system service is brought forward. Finally, the formalized description and execution system of testing models are given, with which we can realize real-time, closed loop, mad automated system testing for embedded real-time software.

关键词： embedded real-time software software testing testing modeling simulation

CALIBRATION OF A 6-DOF SPACE ROBOT USING GENETIC ALGORITHM

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Chinese Journal of Mechanical Engineering 2008年第6期21卷 6-13页

作者： liu Yu jiang Yanshu LIANG bin XU Wenfu College of Science and Technology Harbin Institute of Technology Harbin 150001 China Department of Automation Harbin University of Science and Technology Harbin 150008 China Colloge of Science and Technology Harbin Institute of Technology Harbin 150001 China

The kinematic error model of a 6-DOF space robot is deduced, and the cost function of kinematic parameter identification is built. With the aid of the genetic algorithm （GA） that has the powerful global adaptive probabilistic search ability, 24 parameters of the robot are identified through simulation, which makes the pose （position and orientation） accuracy of the robot a great improvement. In the process of the calibration, stochastic measurement noises are considered. Lastly, generalization of the identified kinematic parameters in the whole workspace of the robot is discussed. The simulation results show that calibrating the robot with GA is very stable and not sensitive to measurement noise. Moreover, even if the robot＇s kinematic parameters are relative, GA still has strong search ability to find the optimum solution.

关键词： Robot calibration Position and orientation accuracy Measurement noises Genetic algorithm

Microstructure Distribution and Tensile Anisotropy of Dissimilar Friction Stir Welded AM60 and AZ31 Magnesium Alloys

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Acta Metallurgica Sinica(English Letters) 2020年第11期33卷 1487-1504页

作者： Jun-Lei Zhang Han liu Yu-Lu Xie Guang-Sheng Huang Xiang Chen bin jiang ai-TaoTang Fu-Sheng Pan State Key Laboratory of Mechanical Transmission College of Materials Science and EngineeringChongqing UniversityChongqing 400044China National Engineering Research Center for Mg Alloys Chongqing UniversityChongqing 400044China

The microstructure distribution,tensile anisotropy and fracture behaviors in the dissimilar friction stir welded joint of AM60/AZ31 alloys were *** results showed that a significant grain refinement and an orientation fluctuation occurred in the *** grain size of AZ31 side in joint was obviously smaller than that of AM60 *** was a higher percentage of low angle grain boundaries(LAGBs)and a lower degree of recrystallization in AZ31 side compared with those in AM60 side,especially for the thermo-mechanically affected zone in AZ31 *** discrepancies of grain size distribution,recrystallization behavior and LAGBs in joint depended on the different initial state of two metals and the inhomogeneous temperature distribution in *** addition,the(0001)basal plane in weld was roughly parallel to the surface of the pin,showing the symmetrically distributed texture *** joint showed an obvious tensile anisotropy due to the special texture *** comprehensive tensile properties of joint along the three directions decreased in the order:welding direction,45°direction and transverse *** maximum ultimate tensile strength,yield strength and elongation of the joint were 242 MPa,116 MPa and 21.2%,*** fluctuations of grain size and texture in joint affected the fracture behavior of samples in the three directions.

关键词： Friction stir welding Dissimilar joint Texture Anisotropy Tensile properties