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State estimation over a communication network:measurement or estimate communication?

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控制理论与应用（英文版） 2010年第1期8卷 20-26页

作者： Ling SHI Ye YUAN Michael Z. q. chen Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong China Control Group Department of Engineering University of Cambridge Cambridge CB2 IPZ UK Department of Automation Nanjing University of Science and Technology Nanjing Jiangsu 210094 China)

In this paper we consider the problem of state estimation over a communication network. Using estimation quality as a metric, two communication schemes are studied and compared. In scheme one, each sensor node communicates its measurement data to the remote estimator, while in scheme two, each sensor node communicates its local state estimate to the remote estimator. we show that with perfect communication link, if the sensor has unlimited computation capability, the two schemes produce the same estimate at the estimator, and if the sensor has limited computation capability, scheme one is always better than scheme two. On the other hand, when data packet drops occur over the communication link, we show that if the sensor has unlimited computation capability, scheme two always outperforms scheme one, and if the sensor has limited computation capability, we show that in general there exists a critical packet arrival rate, above which scheme one outperforms scheme two. Simulations are provided to demonstrate the two schemes under various circumstances.

关键词： Networked estimation Kalman filtering Packet-dropping network

Network Embedding Algorithm for Vulnerability Assessment of Power Transmission Lines Using Integrated Structure and Attribute Information

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 351-360页

作者： Xianglong Lian Tong qian Zepeng Li Xingyu chen wenhu Tang q.H.wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China

In power systems,failures of vulnerable lines can trigger large-scale cascading failures,and vulnerability assessment is dedicated to locating these lines and reducing the risks of such *** on a structure and attribute network embedding(SANE)algorithm,a novel quantitative vulnerability analysis method is proposed to identify vulnerable lines in this ***,a two-layered random walk network with topological and electrical properties of transmission lines is ***,based on the weighted degree of nodes in the two-layered network,the inter-layer and intra-layer walking transition probabilities are developed to obtain walk ***,a word2Vec algorithm is applied to obtain lowdimension vectors representing transmission lines,according to obtained walk sequences for calculating the vulnerability index of transmissions ***,the proposed method is compared with three widely used methods in two test *** show the network embedding based method is superior to those comparison methods and can provide guidance for identifying vulnerable lines.

关键词： Network embedding random walk transmission lines vulnerability assessment

Three principles for preparing Al wire with high strength and high electrical conductivity

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Journal of Materials Science & Technology 2019年第5期35卷 742-751页

作者： J.P.Hou R.Li q.wang H.Y.Yu Z.J.Zhang q.Y.chen H.Ma X.M.wu X.w.Li Z.F.Zhang Materials Fatigue and Fracture Division Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China National quality Supervision & Inspection Center of Electrical Equipment Safety Performance Zhejiang Huadian Equipment Testing Institute Hangzhou 310015 China Electric Power Research Institute of Liaoning Electric Power Co. Ltd. Liaoning Electric Power Co. Ltd. Shenyang 110006 China Department of Materials Physics and Chemistry School of Materials Science and Engineering Key Laboratory for Anisotropy and Texture of Materials Ministry of Education Northeastern University Shenyang 110819 China

The trade-off relation between the strength and the electrical conductivity has been a Iong-standing dilemma in metallic materials. In the study, three key principles, *** grains, sharp texture and nano-scale precipitates, were presented for preparing Al wire with high strength and high electrical conductivity based on the specially designed experiments for breaking the mutually exclusive relation between the strength and the electrical conductivity. The results show that the elongated grains could lead to a higher electrical conductivity in Al wire without sacrificing the strength;while, the sharp texture can efficiently strengthen the Al wire without influencing the electrical conductivity. Furthermore, nano-scale precipitates with proper size can simultaneously improve the strength and electrical conductivity of Al alloy wire. Under the guidance of the above three key principles, Al wires with high strength and high conductivity were prepared.

关键词： Al wire Texture Precipitates Strength Electrical conductivity

Investigation of the crack problem in non-local piezoelectric materials under combined electromechanical loadings

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Acta Mechanica Sinica 2009年第2期25卷 219-225页

作者： q. Li Y. chen School of Aerospace, Xi’an Jiao-Tong University,710049 Xi’an, China School of Aerospace Xi’an Jiao-Tong University Xi’an China

The present investigation of the crack problem in piezoelectric materials is performed based on the non-local theory. After some manipulations, the impermeable crack, the permeable crack （the crack gap is full of NaCI solution）, and the semi-permeable crack （the crack gap is full of air or silicon oil） are reduced to a uniform formulation by assuming the normal electric displacement on the crack surfaces to be an unknown variable. Thus, a triple integral equation with the unknown normal electric displacement is established. By using the Newton iterative method and solving the triple integral equation, it is found that the normal electric displacement on the crack surfaces is no longer a constant as determined by previous studies, rather, it depends upon the remote combined electromechanical loadings. Numerical results of the stresses and electric displacement fields show that there are no singularities at the crack tips so that the stresses remain finite. It is of great significance that the concrete electric boundary condition on the crack surfaces exerts significant influence on the near-tip fields and in this way plays an important role in evaluating the crack stability in the non-local piezoelectric materials. More specifically, the impermeable crack model always overestimates the finite stresses at the crack tips, whereas the permeable crack model always underestimates them.

关键词： Crack Non-local piezoelectric materialsImpermeable Permeable Semi-permeable

3D－qSAR　STUDY　ON　HUPERZINE　A　ANALOGS　wITH　MOLECULAR　MODELING　AND　COMPARATIVE　MOLECULAR　FIELD　ANALYSIS（COMFA）　METHODS

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Chinese Chemical Letters 1996年第3期7卷 253-256页

作者： Jiang, HL chen, KX chen, JZ Tang, Y wang, qM Li, q Shen, X Ji, RY CHINESE ACAD SCI SHANGHAI INST MAT MEDSHANGHAI 200031PEOPLES R CHINA

On the basis of conformational search for ten huperzine A analogs according to the structure ofAChE active site witll our approach BCSPL,we performed a 3D-qSAR analysis for these compounds usingmolecular modeling and CoMFA method. The calculation results can be used to explain the relationshipbetween the structUre properties and the activities.

关键词： qSAR STUDY ON HUPERZINE ANALYSIS ANALOGS

OPTICAL CHARACTERIZATION OF TiO_2 THIN FILM ON SILICON SUBSTRATE DEPOSITED BY DC REACTIVE MAGNETRON SPUTTERING

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 194-198页

作者： H.q.wang H.Shen D.C.Ba B.w.wang L.S.wen D.chen SchoolofMechanismandAutomobile ShenyangInstituteofAeronauticalEngineeringShenyang110034Ghina／／MechanismandAeronauticalCollegeNortheasternUniversityShenyang110004China TheSchoolofPhysicsandEngineering ZhongshanUniversityGuangzhou510275Ghina MechanismandAeronauticalCollege NortheasternUniversityShenyang110004China GuangzhouInstimdeofEnergyConversion Guangzhou510070China InstituteofMetalResearch TheChineseAcademyofSciencesShenyang110016China MaterialandScienceEngineeringAcademy SouthChinaUniversityofTechnologyGuangzhou510641China

TiO2 thin film has attracted considerable attention in recent years, due to its different refractive index and transparency with amorphous and different crysta ls in the visible and near-infrared wavelength region, high dielectric constant, wide band gap, high wear resistance and stability, etc, for which make it being used in many fields. This paper aims to investigate the optical characterizatio n of thin film TiO2 on silicon wafer. The TiO2 thin films were prepared by DC re active magnetron sputtering process from Ti target. The reflectivity of the film s was measured by UV-3101PC, and the index of refraction (n) and extinction coef ficient (k) were measured by n & k Analyzer 1200.

关键词： optical characterization TiO2 thin film DC reactive magnetron sputtering n & k

Nonconforming FEMs for the p-Laplace Problem

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Advances in Applied Mathematics and Mechanics 2018年第6期10卷 1365-1383页

作者： D.J.Liu A.q.Li Z.R.chen Department of Mathematics Shanghai UniversityShanghai 200444China

The p-Laplace problems in topology optimization eventually lead to a degenerate convex minimization problem E(v):=∫_(Ω)w(■v)dx-∫_(Ω)fvdx for v∈w_(0)^(1,p)(Ω)with unique minimizer u and stress s:=Dw(ru).This paper proposes the discrete Raviart-Thomas mixed finite element method(dRT-MFEM)and establishes its equivalence with the Crouzeix-Raviart nonconforming finite element method(CR-NCFEM).The sharper quasi-norm a priori and a posteriori error estimates of this two methods are *** experiments are provided to verify the analysis.

关键词： Adaptive finite element methods nonconforming p-Laplace problem dual energy

Thin Film of Mesoporous MCM-41 Grown on Indium-Tin-Oxide Glass Substrate

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Chinese Chemical Letters 1999年第4期10卷 335-338页

作者： Zhang, J Xiong, HM Ding, H Cai, q chen, JS Pang, wq Jilin Univ Key Lab Inorgan Synthesis & Preparat Chem Changchun 130023 Peoples R China Jilin Univ Dept Chem Changchun 130023 Peoples R China Chongqing Teachers Coll Dept Chem Yongchuan 402168 Peoples R China

From a basic solution containing celyltrimethylammonium cations as the template, thin film of mesoporous MCM-41 has been grown on the surface of a pre-treated indium-tin-oxide conducting glass substrate. The channel axis of the film is oriented parallel with the surface plane of the substrate, and the film is stable after careful removal of template in vacuum.

关键词： mesoporous MCM-41 film ITO glass substrate basic medium synthesis

RESEARCH ON HOT FORMING PROCESS OF A RETAINING RING OF HIGH-NITROGEN STEEL

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 767-770页

作者： H.q.chen J.S.Liu H.G.Guo DepartmentofMaterialScienceandEngineering TaiyuanHeavyMachineryInstituteTaiyuan030024China

Mn18Cr18N, the high-nitrogen steel, is the 2nd generation material for manufacturing the retaining ring of firepower generators. In this paper, the hot deformation behavior of the material was investigated by thermo-mechanical modeling tests. And the flow stress curves of the steel were obtained for various combinations of the temperature and strain rate. Based on the results of the tests, the complex forming process of a retaining ring including punching, expanding and extrusion with an enclosure was put forward and simulated by means of numerical simulation method. The results indicate that the process is a novel and force-saved practical technology for manufacturing heavy retaining rings.

关键词： Mn18Cr18N high-nitrogen steel a retaining ring the punching with an enclosure process expanding-extrusion complex forming