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SVD-TLS extending Prony algorithm for extracting UWB radar target feature

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Journal of Systems Engineering and Electronics 2008年第2期19卷 286-291页

作者： Liu Donghong Hu wenlong chen Zhijie The Radar Institute Equipment Academy of Air Force Beijing 100085 P. R. China

A new method, SVD-TLS extending Prony algorithm, is introduced for extracting UWB radar target features. The method is a modified classical Prony method based on singular value decomposition and total least squares that can improve robust for spectrum estimation. Simulation results show that poles and residuum of target echo can be extracted effectively using this method, and at the same time, random noises can be restrained to some degree. It is applicable for target feature extraction such as UWB radar or other high resolution range radars.

关键词： UWB radar Prony algorithm radar target feature singular value decomposition.

SuperFlow:A Reliable and Scalable Architecture for Large-Scale Enterprise Networks

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Chinese Journal of Electronics 2016年第6期25卷 1134-1140页

作者： HU Guangwu JIANG Yong chen wenlong chen Tan WU Jianping School of Computer Science Shenzhen Institute of Information Technology Graduate School at Shenzhen Tsinghua University Information Engineering College Capital Normal University College of Computer Science Beijing University of Technology Department of Computer Science and Technology Tsinghua University

With the increasing number of users, enterprise networks have become more and more important, but it also faced new challenges in various *** OpenF low, the promising de facto Software defined networking(SDN) scheme which can provide finegrained and flow-level control for enterprise networks, yet it still has a few undesirable designs in credibility and scalability. Inspired by OpenF low-included many excellent studies, we have proposed a reliable and scalable architecture—Super Flow for large-scale enterprise networks in this paper. It inherits the merits of OpenF low, and overcomes OpenF lows limitations by introducing some novel *** prototype experiment has proved that Super Flow possesses these features with desirable performance.

关键词： Enterprise network SuperFlow OpenFlow Source address validation improvement(SAVI) Software defined networking(SDN)

Even FIB Decomposition Model Based on Storage and Traffic Balancing

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Chinese Journal of Electronics 2017年第4期26卷 681-687页

作者： chen wenlong WANG Shuxian TANG Xiaolan LAN Lijing College of Information Engineering Capital Normal University

The sharp expansion of the FIB table rapidly aggravates the hardware cost of Line cards(LCs) in the high-performance distributed routers. The storage optimization of FIB becomes a research hotspot. The traffic load of each LC is still very different in the current nonfull backup storage, which has a deep impact on the overall forwarding performance of the routers. An even FIB decomposition model was proposed, namely FEST, aiming for a two-dimension balance in both storage and traffic. Based on the splitting and distribution filters, FEST starts with splitting the root prefixes and utilizes the optimal adaptation algorithm to evenly distribute the routing entries and the traffic to LCs without the modification of the hardware designs of the current LCs. Eventually FEST uses the location routing to determine the location and the forwarding of every packet. The experiment results show that different LCs get very even numbers of routing entries and relatively even traffic in FEST.

关键词： FIB Decomposition Storage Traffic

LPR-Trie: A Fast IPv6 Routing Lookup Algorithm with Virtual Nodes

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China Communications 2022年第10期19卷 1-11页

作者： wenlong chen Diya Liu Jiacheng Wang Xiaolan Tang The College of Information Engineering Capital Normal UniversityBeijing 100048China

The number of IPv6 routes in todays backbone routers has grown rapidly,which has put tremendous pressure on route lookup and *** on the analysis of IPv6 address prefix length and distribution characteristics,this paper proposes an IPv6 route lookup architecture called *** core idea of the algorithm is to utilize more spaces and accelerate routing ***,we put forward the concept of virtual nodes,and leverage the link between virtual nodes and ordinary nodes to accelerate routing *** provide the longest prefix routing entry(LPR)calculation algorithm to achieve the longest prefix *** experimental results show that the virtual node mechanism increases the search speed up to 244%,and the virtual nodes have better stability by setting an appropriate keep-alive time according to the characteristics of actual *** paper shows that our design improves the routing lookup speed and have better memory utilization.

关键词： IPv6 route lookup longest prefix match virtual node Trie

High-temperature oxidation behavior and analysis of impedance spectroscopy of 7YSZ thermal barrier coating prepared by plasma spray-physical vapor deposition

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Chinese Journal of Aeronautics 2018年第8期31卷 1764-1773页

作者： wenlong chen Min LIU Jifu ZHANG Ziqian DENG Jie MAO School of Materials and Energy Guangdong University of Technology Guangzhou 510006 China National Engineering Laboratory for Modern Materials Surface Engineering Technology & the Key Lab of Guangdong for Modern Surface Engineering Technology Guangdong Institute of New Materials Guangzhou 510650 China

Quasi-columnar structure 7YSZ（yttria stabilized zirconia） thermal barrier coatings（TBCs） are prepared by plasma spray-physical vapor deposition（PS-PVD） onto pretreated and un-pretreated bond coating, respectively. An isothermal oxidation experiment of 7YSZ TBCs is carried out in the atmosphere of 950 °C in order to simulate the high-temperature oxidation process of engine blades. The isothermal oxidation process of 7YSZ thermal barrier coatings is investigated systematically by impedance spectroscopy. The electrochemical physical model and equivalent circuit of columnar 7YSZ coatings are established. Results show that the isothermal oxidation kinetic curve of columnar 7YSZ thermal barrier coatings appears to follow the parabolic law. A pretreatment of bond coating can reduce the growth rate of the thermally grown oxide（TGO） layer, restraining the initiation and propagation of microcracks between YSZ and TGO layers. The oxidation rate constants of 7YSZ coatings with pretreated and un-pretreated bond coating are 0.101×10^（-12） cm^2·s^（-1） and 0.115 × 10^（-13） cm^2 ·s^（-1）, respectively. Impedance analysis shows that the content of oxygen vacancies decreases and the density increases after the TGO layer is oxidized for 150 h. In addition, shrinkage microcracks formed by sintering during the oxidation process is the main reason for an increase of the capacitance and a decrease of the resistance in the grain boundary of YSZ.

关键词： Bond coating Impedance spectroscopyIsothermal oxidation PS-PVD TBCs

Evaluation and attribution of trends in compound dry-hot events for major river basins in China

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Science China Earth Sciences 2024年第1期67卷 79-91页

作者： Shaotang XIONG Tongtiegang ZHAO chengchao GUO Yu TIAN Fang YANG wenlong chen Xiaohong chen Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources&Sun Yatsen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China China Institute of Water Resource and Hydropower Research Beijing 100038China Pearl River Hydraulic Research Institute Guangzhou 510611China

Concurrent compound dry and hot events(CDHEs)amplified more damange on the ecosystems and human society than individual *** climate change,compound dry and hot events become more frequent on a global *** paper proposes a mathematical method to quantitatively attribute changes of CDHEs to changes of precipitation,change in temperature and change in the dependence between precipitation and *** attribution is achieved by formulating the total differential equation of the return period of CDHEs among Meta-gaussian model.A case study of China is devised based on monthly precipitation and temperature data during the period from 1921 to 2020 for 80 major river *** is found that temperature is the main driving factor of increases in CDHEs for 49 major river basins in China,except for the upper and middle reaches of the Yangtze *** West China,precipitation changes drove the increase in CDHEs in 18 river basins(23%),particularly in parts of North Xinjiang,Qinghai and *** the other hand,dependence between precipitation and temperature dominated changes of CDHEs in 13 river basins(16%)of China with other factors,including parts of South China,East China and Northwestern ***,changes in both the mean and spread of precipitation and temperature can also contribute to changes in CDHEs.

关键词： Climate extreme Compound dry and hot extreme Precipitation Temperature Return period

Numerical Simulation of Dam-Break Flooding of Cascade Reservoirs

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Transactions of Tianjin University 2017年第6期23卷 570-581页

作者： Zhengyin Zhou Xiaoling Wang wenlong chen Shaohui Deng Minghui Liu Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Previous studies at home and abroad have mainly focused on single dam-break, and little attention has been paid so far to the dam-break of cascade reservoirs. Multi-source flooding, which can lead to three-dimensional turbulent phenomena and superposition effects, is the main difference between the dam-break of cascade and single reservoirs. Detailed descriptions of the coupled numerical simulation of multi-source flooding have little been reported, and the initial wet riverbed is rarely considered in current models. Therefore, in this paper, a method based on the three-dimensional (Formula presented.) turbulence model coupled with the volume-of-fluid method is proposed to simulate the dam-break flooding of cascade reservoirs. The upstream river, reservoir, and downstream river are connected by the internal boundary method, and the initial conditions, including river flow and reservoir water, are determined according to the results of the numerical simulation. Coupled numerical simulation of different dam-break flooding is then achieved. The present work solves the challenges presented by the enhancement and superposition of natural river flow, upstream flooding, and downstream flooding. This paper provides a theoretical basis for future studies on the dam-break flood routing of cascade reservoirs. © 2017 Tianjin University and Springer-Verlag GmbH Germany

关键词： Dams Floods Flow of water Numerical methods Numerical models Rivers Stream flow Turbulence models

Experimental and numerical studies on progressive debonding of grouted rock bolts

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International Journal of Mining Science and Technology 2022年第1期32卷 63-74页

作者： Hao Shi Lei Song Houquan Zhang wenlong chen Huasheng Lin Danqi Li Guozhu Wang Huayun Zhao State Key Laboratory for Geomechanics&Deep Underground Engineering School of Mechanics&Civil EngineeringChina University of Mining and TechnologyXuzhou 221116China School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001China School of Water Energy and EnvironmentCranfield UniversityCranfield MK430ALUK Glencore Coal Assets Australia Mount ThorleyNSW 2330Australia WA School of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityKalgoorlie WA6430Australia

Understanding the mechanism of progressive debonding of bolts is of great significance for underground *** this paper,both laboratory experiment and numerical simulation of the pull-out tests were *** experimental pull-out test specimens were prepared using cement mortar material,and a relationship between the pull-out strength of the bolt and the uniaxial compressive strength(UCS)of cement mortar material specimen was *** locations of crack developed in the pull-out process were identified using the acoustic emission(AE)*** pull-out test was reproduced using 2D Particle Flow Code(PFC^(2D))with calibrated *** experimental results show that the axial displacement of the cement mortar material at the peak load during the test was approximately 5 mm for cement-based grout of all *** contrast,the peak load of the bolt increased with the UCS of the confining *** peak load,cracks propagated to less than one half of the anchorage length,indicating a lag between crack propagation and axial bolt load *** simulation results show that the dilatation between the bolt and the rock induced cracks and extended the force field along the anchorage direction;and,it was identified as the major contributing factor for the pull-out failure of rock bolt.

关键词： Bolt pull-out test Bolt failure process AE positioning Meso-interaction PFC2D simulation

Influence of heat treatment on microstructure,mechanical and corrosion behavior of WE43 alloy fabricated by laser-beam powder bed fusion

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International Journal of Extreme Manufacturing 2024年第1期6卷 258-275页

作者： chenrong Ling Qiang Li Zhe Zhang Youwen Yang Wenhao Zhou wenlong chen Zhi Dong Chunrong Pan Cijun Shuai College of Mechanical and Electrical Engineering Jiangxi University of Science and TechnologyGanzhou 341000People’s Republic of China School of Mechanical and Electronic Engineering Suzhou UniversitySuzhou 234000People’s Republic of China Shaanxi Key Laboratory of Biomedical Metal Materials Northwest Institute for Non-ferrous Metal ResearchXi’an 710016People’s Republic of China Department of Orthopedics First Afffliated Hospital of Gannan Medical CollegeGanzhou 341000People’s Republic of China School of Mechanical and Automotive Engineering South China university of technologyGuangzhou 510641People’s Republic of China State Key Laboratory of High-Performance Complex Manufacturing Central South UniversityChangsha 410083People’s Republic of China Double Medical Technology Inc. Xiamen 361026People’s Republic of China

Magnesium(Mg)alloys are considered to be a new generation of revolutionary medical ***-beam powder bed fusion(PBF-LB)is suitable for fabricating metal implants withpersonalized and complicated ***,the as-built part usually exhibits undesirable microstructure and unsatisfactory *** this work,WE43 parts were firstly fabricated by PBF-LB and then subjected to heat *** a high densification rate of 99.91%was achieved using suitable processes,the as-built parts exhibited anisotropic and layeredmicrostructure with heterogeneously precipitated Nd-rich *** heat treatment,fine and nano-scaled Mg24Y5particles were ***,theα-Mg grainsunderwent recrystallization and turned coarsened slightly,which effectively weakened thetexture intensity and reduced the *** a consequence,the yield strength and ultimate tensile strength were significantly improved to(250.2±3.5)MPa and(312±3.7)MPa,respectively,while the elongation was still maintained at a high level of 15.2%.Furthermore,the homogenized microstructure reduced the tendency of localized corrosion and favoredthe development of uniform passivation ***,the degradation rate of WE43 parts was decreased by an order of ***,in-vitro cell experiments proved their favorable biocompatibility.

关键词： laser-beam powder bed fusion WE43 alloys heat treatment mechanical performance biodegradation behavior