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Achieving the capacity of half-duplex degraded relay channels using polar coding

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Chinese Journal of Aeronautics 2014年第3期27卷 584-592页

作者： Duo Bin Wang Zhenyong gu Xuemai guo qing School of Electronics and Information Engineering Harbin Institute of Technology

In this paper, a novel transmission protocol based on polar coding is proposed for the half-duplex degraded relay channel. In the proposed protocol, referred to as the partial message relaying, the relay only needs to forward a part of the decoded source message that the destination needs according to the exquisite nested structure of polar codes. Theoretically, it is proved that the scheme can achieve the capacity of the half-duplex relay channel under the decode-and-forward （DF） cooperation strategy while enjoying low encoding/decoding complexity. Practically, in order to minimize the global transmission power, the optimization of the power allocation is performed between the source and the relay by using information theoretic tools. Furthermore, a joint iterative soft parallel interference cancellation receiver structure is developed to suit to the proposed scheme. Simulation results show that the proposed scheme outperforms the conventional scheme designed by low-density parity-check （LDPC） codes.

关键词： Channel capacity Decode-and-forward:Half-duplex Iterative decoding Polar coding Relay channel

Time synchronization and ranging under unknown positions and velocities

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Science China(Technological Sciences) 2017年第2期60卷 271-281页

作者： gu XiaoBo CHANG qing XU Yong WANG Dun School of Electronic & Information Engineering Beihang University Space Star Technology Co. Ltd

The process to achieve time synchronization and ranging for a network of mobile nodes is raising a concern among researchers, and hence a variety of joint time synchronization and ranging algorithms have been proposed in recent years. However, few of them handle the case of all-node motion under unknown positions and velocities. This study addresses the problem of determining ranging and time synchronization for a group of nodes moving within a local area. First, we examined several models of clock discrepancy and synchronous two-way ranging. Based upon these models, we present a solution for time synchronization with known positions and velocities. Next, we propose a functional model that jointly estimates the clock skew, clock offset, and time of flight in the absence of a priori knowledge for a pair of mobile nodes. Then, we extend this model to a network-wide time synchronization scheme by way of a global least square estimator. We also discuss the advantages and disadvantages of our model compared to the existing algorithms, and we provide some applicable scenarios as well. Finally, we show that the simulation results verify the validity of our analysis.

关键词： time synchronization two-way ranging relative motion clock model joint estimation

An adaptive fuzzy filter for coding artifacts removal in video and image

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 841-848页

作者： WU Jing YE Xiu-qing gu Wei-kang Department of Information and Communication Engineering Zhejiang University Hangzhou 310027 China

This paper proposes a new adaptive post-filtering algorithm to remove coding artifacts in block-based video coder. The proposed method concentrates on blocking and ringing artifacts removal. For de-blocking, the blocking strength is identified to determine the filtering range, and the maximum quantization parameter of the image is used to adapt the 1D fuzzy filter. For de-ringing, besides the edge detection, a complementary ringing detection method is proposed to locate the neglected ringing blocks, and the gradient threshold is adopted to adjust the parameter of 2D fuzzy filter. Experiments are performed on the MPEG-4 sequences. Compared with other methods, the proposed one achieves better detail preservation and artifacts removal performance with lower computational cost.

关键词： Adaptive fuzzy filter Blocking artifacts Ringing artifacts De-blocking De-ringing

Collision-induced Rotational Energy Transfer in an Atom-Diatom System

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Chinese Journal of Chemical Physics 2008年第5期21卷 457-462页

作者： Yan-qing Ni jian Li Feng-cai Ma Department of Physics Liaoning University Shenyang 110036 China Department of Science Shenyang Institute of Aeronautical Engineering Shengyang 110036 China

As a further theoretical study of the collision-induced quantum interference on rotational energy transfer in an atom-diatom system, based on the first-Born approximation of time-dependent perturbation theory, taking into account the anisotropic Lennard-Jones interaction potential and the long-range interaction potential, the differential interference angles in singlet-triplet mixed states of CO A^1Π（v=9）-e3∑-（v=1） system in collision with He, Ne, Ar, and other partners were calculated theoretically. The relationships of differential interference angle versus impact parameters, including collision parameter b and velocity, are obtained.

关键词： Rotational energy transfer Collision-induced quantum interference Interference angle

Influence of Extrusion Joint on Microstructural Evolution and Properties of Mg Alloy Sheet

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Acta Metallurgica Sinica(English Letters) 2016年第5期29卷 475-482页

作者： qing-Shan Yang Zu-jian Yu Hu-Cheng Pan qing-Wei Dai jian-Hui Li School of Metallurgy and Materials Engineering Chongqing University of Science and TechnologyChongqing 401331China Chongqing Academy of Science and Technology Chongqing 401123China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern UniversityShenyang 110819China

The mechanical behaviour of AZ31 magnesium alloy sheet with the extrusion joint （EJ） was evaluated. Extruded joint of AZ31 alloy sheets was obtained by the hot extrusion process. Tensile tests were carried out along the extrusion direction at room temperature, and both the non-uniform plastic deformation and the fracture behaviour were studied. It is found that the samples with EJ present significantly deteriorated mechanical properties compared with the EJ- free counterpart. Inhomogeneous rnicrostructure distribution around EJ zone brings in the uncoordinated deformation due to the high density of {1012} twins which were readily activated during plastic deformation.

关键词： Mg alloy Microstructure Twin Texture Extrusion joint

Product Specification Analysis for Modular Product Design Using Big Sales Data

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 19-33页

作者： jian Zhang Bingbing Li qingjin Peng Peihua gu Department of Mechanical Engineering Shantou UniversityShantou515063China Department of Mechanical Engineering University of ManitobaManitobaR3T 5V6Canada International Institute for Innovative Design and Intelligent Manufacturing of Tianjin University Shaoxing312000China School of Mechanical Engineering Tianjin UniversityTianjin300350China

Big data on product sales are an emerging resource for supporting modular product design to meet diversified customers’requirements of product specification *** better facilitate decision-making of modular product design,correlations among specifications and components originated from customers’conscious and subconscious preferences can be investigated by using big data on product *** study proposes a framework and the associated methods for supporting modular product design decisions based on correlation analysis of product specifications and components using big sales *** correlations of the product specifications are determined by analyzing the collected product sales *** building the relations between the product components and specifications,a matrix for measuring the correlation among product components is formed for component *** rules for supporting the decision making of modular product design are proposed based on the frequency analysis of the specification values per component cluster.A case study of electric vehicles illustrates the application of the proposed method.

关键词： Modular product design Customer preference Product specifications Correlation analysis Big sales data Electric vehicle

Vapor-assisted epitaxial growth of porphyrin-based MOF thin film for nonlinear optical limiting

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Science China Chemistry 2020年第8期63卷 1059-1065页

作者： Yi-Hong Xiao Zhi-Gang gu jian Zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China

Fabrication of metal-organic frameworks(MOFs)thin films has been an efficient way to expand their functionalities and ***,we use the vapor-assisted deposition(VAD)method to epitaxially grow a porphyrin-based MOF PCN-222 *** is,vapor source assists to deposit pre-treated precursor solution on quartz substrate to form a continuous PCN-222 ***,utilizing the post-treated encapsulation of functional carbon-based nanoparticles,the carbon nanodots(CND)and Pt doped CND(Pt/CND)are well loaded into the pores of PCN-222 film,the size(~3.1 nm)of which is highly close to the pore size of the corresponding MOF(~3.7 nm).The Z-scan results reveal that PCN-222 film exhibits high reverse saturable *** addition,encapsulation of carbon based nanodots into PCN-222 film could enhance the nonlinear optical limiting effect benefiting from the host-guest *** study serves to present both the available toolbox of thin film preparation and high potential for precise synthetic nanocomposite films in optical limiting devices.

关键词： metal-organic framework epitaxial growth porphyrin thin film nonlinear optical property

Fatigue life research and experimental verification of superalloy thin-walled structures subjected to thermal-acoustic loads

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Chinese Journal of Aeronautics 2020年第2期33卷 598-608页

作者： jian WANG Fengtong ZHAO Yundong SHA Song gu Department of Aircraft Maintenance Engineering Chengdu Aeronautic PolytechnicChengdu 610100China Liaoning Key Laboratory of Advanced Test Technology for Aeronautical Propulsion System Shenyang Aerospace UniversityShenyang 110136China

Rapid alternating stress is formed in structure subjected to harsh thermal-acoustic loads,which will affect fatigue performance and reduce fatigue life ***,fatigue experiment of superalloy thin-walled structure was carried out to obtain fatigue damage location and failure time of the experiment specimen,and S-iN curves of superalloy thin-walled structure at 723 K were ***,dynamic response simulation of superalloy thin-walled structure under the same load as experiment was implemented,and fatigue life was estimated based on the fatigue life prediction model which mainly included:improved rain-flow counting method,Morrow average stress model and Miner linear cumulative damage ***,comparisons between simulation solutions and experimental results achieved a consistency,which verified the validity of the Fatigue Life Prediction Model(FLPM).Moreover,taking a rectangle plate as the analysis object,the distributions of Fain-low circulation blocks and damage levels of the structure were discussed ***,current research indicates that in pre-buckling the structure is in softened area and fatigue life decreases with the increase of temperature;in post-buckling the structure is in hardened area and fatigue life increases with the increase of temperature within a certain range.

关键词： Experimental verification Fatigue life Improved rain-flow counting method Rain-flow cycle matrix Rain-flow damage matrix Thermal-acoustic load Thin-walled structures

A review on conventional and nonconventional machining of SiC particle-reinforced aluminium matrix composites

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Advances in Manufacturing 2020年第3期8卷 279-315页

作者： Ji-Peng Chen Lin gu guo-jian He School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037People’s Republic of China Department of Mechanical Engineering Polytechnic University of MilanPiazza Leonardo da Vinci 32Milan 20133Italy State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

Among the various types of metal matrix composites,SiC particle-reinforced aluminum matrix composites(SiCp/Al)are finding increasing applications in many industrial fields such as aerospace,automotive,and ***,SiCp/Al composites are considered as difficult-to-cut materials due to the hard ceramic reinforcement,which causes severe machinability degradation by increasing cutting tool wear,cutting force,*** improve the machinability of SiCp/Al composites,many techniques including conventional and nonconventional machining processes have been *** purpose of this study is to evaluate the machining performance of SiCp/Al composites using conventional machining,i.e.,turning,milling,drilling,and grinding,and using nonconventional machining,namely electrical discharge machining(EDM),powder mixed EDM,wire EDM,electrochemical machining,and newly developed high-efficiency machining technologies,e.g.,blasting erosion arc *** research not only presents an overview of the machining aspects of SiCp/Al composites using various processing technologies but also establishes optimization parameters as reference of industry applications.

关键词： SiCp/Al Machining Conventional Wear mechanism Nonconventional Performance