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Synthesis and Structural Characterization of Bis(2,2'-bpy)bis(azide)cobalt(Ⅲ)nitrate dihydrate

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Chinese Journal of Structural Chemistry 2002年第3期21卷 260-263页

作者： CHEN hong-ji Department of Chemistry Jinan UniversityGuangzhou 510632China

The title complex [CoIII(2, 2?bpy)2(N3)2]種O3?H2O was obtained by an auto-oxidization reaction of cobalt nitrate with 2, 2-bpy and sodium azide in aqueous solution at room temperature, and violet single crystals were prepared in ethanol solution. The structure was determined by X-ray crystallography. The crystal is of triclinic, space group P ?with a = 8.285(4), b = 11.990(8), c = 12.596(7) ? a = 86.630(3), b = 86.280(5), g = 71.130(10)? C20H20CoN11O5, Mr = 553.40, Z = 2, V = 1180.6(12) ?, F(000) = 568, Dc = 1.557 g/cm3, m = 0.784 mm-1, R = 0.0403 and wR = 0.1008. The title complex consists of a [CoⅢ(2, 2?bpy)2(N3)2]+ cation, a NO3- anion and two lattice water molecules. The center CoⅢ ion coordinated by two chelating 2, 2?bpy ligands and two terminal azide groups with a CoN6 coordination environment exhibits a distorted octahedral geometry.

关键词： complex,2,2’-bipyridine sodium azide synthesis crystal structure

An extended stress-based method for orientation angle optimization of laminated composite structures

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Acta Mechanica Sinica 2011年第6期27卷 977-985页

作者： jin Zhang Wei-hong Zhang ji-hong Zhu Engineering Simulation and Aerospace Computing （ESAC） The Key Laboratory of Contemporary Design ＆ Integrated Manufacturing Technology Northwestern Polytechnical University 710072 Xi＇ an China

Orientation optimization plays an important role in the lay-up design of composite *** orientation optimization methods face the main problem of huge number of design ***,a patch concept is proposed to reduce the number of design ***,the traditional stress-based method can not deal with patch orientation optimization of composite *** this paper,we propose an extended stress-based method to deal with such *** considered problems are to minimize the mean compliance under multiple load cases or to maximize the eigenvalues of a composite *** numerical examples are solved to demonstrate the efficiency of the new *** is shown that the new method has the ability to deal with constraints on orientation angle,such as symmetric,antisymmetric and discrete orientation angle *** iteration is less time-consuming because no sensitivity analysis is needed and a quick convergence rate can be achieved.

关键词： Structural optimization Composites Laminates Orientation angle optimization

Q-learning for dynamic channel assignment in cognitive wireless local area network with fibre-connected distributed antennas

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The Journal of China Universities of Posts and Telecommunications 2012年第4期19卷 80-85页

作者： LI Yi ji hong Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

Cognitive wireless local area network with fibre-connected distributed antennas （CWLAN-FDA） is a promising and efficient architecture that combines radio over fiber, cognitive radio and distributed antenna technologies to provide high speed/high capacity wireless access at a reasonable cost. In this paper, a Q-learning approach is applied to implement dynamic channel assignment （DCA） in CWLAN-FDA. The cognitive access points （CAPs） select and assign the best channels among the industrial, scientific, and medical （ISM） band for data packet transmission, given that the objective is to minimize external interference and acquire better network-wide performance. The Q-learning method avoids solving complex optimization problem while being able to explore the states of a CWLAN-FDA system during normal operations. Simulation results reveal that the proposed strategy is effective in reducing outage probability and improving network throughput.

关键词： cognitive WLAN fibre-connected distributed antennas Q-learning dynamic channel assignment

Scalable peer-to-peer resource discovering scheme for wireless self-organized networks

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The Journal of China Universities of Posts and Telecommunications 2009年第2期16卷 47-52,57页

作者： LI Xi ji hong Key Laboratory of Universal Wireless Communications Minisa-y of Education Beijing University of Posts and Telecommunications Beijing 100876 China

Peer-to-peer technologies have attracted increasing research attention with fruitful protocols and applications proposed for wired networks. As to mobile environments, there are currently no mature deployments. A novel resource managing and discovering protocol, Cheer, is proposed to realize scalable and effective peer-to-peer lookup in wireless self-organized networks. Cheer resolves the topologies mismatch problem between peer-to-peer overlay networks and actual nodes distribution, allowing for frequent nodes membership changes. With specially designed resource storage table, Cheer also supports multikey and fuzzy lookup. Its hybrid architecture and improved routing scheme based on small-world theory may realize effective lookup routing. Theoretical analysis and simulation results both prove that Cheer makes using peer-to-peer applications in large-scale self-organized mobile networks feasible and promising.

关键词： peer-to-peer small-world resource discovering

Tuning the Learning Rate for Stochastic Variational Inference

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Journal of Computer Science & Technology 2016年第2期31卷 428-436页

作者： Xi-Ming Li ji-hong Ouyang College of Computer Science and Technology Jilin University Changchun 130000 China Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun 130000 China

Stochastic variational inference （SVI） can learn topic models with very big corpora. It optimizes the variational objective by using the stochastic natural gradient algorithm with a decreasing learning rate. This rate is crucial for SVI; however, it is often tuned by hand in real applications. To address this, we develop a novel algorithm, which tunes the learning rate of each iteration adaptively. The proposed algorithm uses the Kullback-Leibler （KL） divergence to measure the similarity between the variational distribution with noisy update and that with batch update, and then optimizes the learning rates by minimizing the KL divergence. We apply our algorithm to two representative topic models： latent Dirichlet allocation and hierarchical Dirichlet process. Experimental results indicate that our algorithm performs better and converges faster than commonly used learning rates.

关键词： stochastic variational inference online learning adaptive learning rate topic model

A Separation Theorem for Stochastic Singular Linear Quadratic Control Problem with Partial Information

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Acta Mathematicae Applicatae Sinica 2013年第2期29卷 303-314页

作者： hong-ji MA Ting HOU College of Science Shandong University of Science and Technology Department of Systems and Control Beijing University of Aeronautics and Astronautics

In this paper, we provide a separation theorem for the singular linear quadratic （LQ） control problem of ItS-type linear systems in the case of the state being partially observable. Above all, the Kalmam Bucy filtering of the dynamics is given by means of Girsanov transformation, by which the suboptimal feedback control of the LQ problem is determined. Furthermore, it is shown that the well-posedness of the LQ problem is equivalent to the solvability of a generalized differential Riccati equation （GDRE）.

关键词： singular optimal control Kalman-Bucy filtering separation theorem linear systems generalizeddifferential Riccati equation

A biarc-based shape optimization approach to reduce stress concentration effects

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Acta Mechanica Sinica 2014年第3期30卷 370-382页

作者： Liang Meng Wei-hong Zhang ji-hong Zhu Liang Xia Engineering Simulation and Aerospace Computing (ESAC) Northwestern Polytechnical University

In order to avoid stress concentration, the shape boundary must be properly designed via shape optimiza- tion. Traditional shape optimization approach eliminates the stress concentration effect by using free-form curve to present the design boundaries without taking the machin- ability into consideration. In most numerical control （NC） machines, linear as well as circular interpolations are used to generate the tool path. Non-circular curves, such as non- uniform rotational B-spline （NURBS）, need other more ad- vanced interpolation functions to formulate the tool path. Forming the circular tool path by approximating the opti- mal free curve boundary with arcs or biarcs is another op- tion. However, these two approaches are both at a cost of sharp expansion of program code and long machining time consequently. Motivated by the success of recent researches on biarcs, a reliable shape optimization approach is pro- posed in this work to directly optimize the shape boundaries with biarcs while the efficiency and precision of traditional method are preserved. Finally, the approach is validated by several illustrative examples.

关键词： Structural shape optimization Biarc Curvefitting NURBS Stress concentration

Synthesis and Crystal Structure of a Dinuclear Complex:Bis[aqua(phen)(4-aba)copper(Ⅱ)nitrate(4-abaH)dihydrate]

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Chinese Journal of Structural Chemistry 2007年第3期26卷 263-266页

作者： LI Yan-Guo CHEN hong-ji Department of Material Science and Engineering Jinan University Guangzhou 510632 China

The title complex has been obtained by the reaction of copper nitrate trihydrate with 4-abaH （4-abaH = 4-aminobenzonic acid） and phenanthroline in ethanol solution, and its structure was determined by X-ray crystallography with the following data： monoclinic, space group C2/c, M, = 1266.13, Cu2C52H54N10O20, a = 25.884（5）, b = 10.205（2）, c = 20.849（4） A, β= 106.34（3）°, Z= 4, V= 5284.7（18） A^3, F（000） = 2616, Dc = 1.591 g/cm^3, μ = 0.896 mm ^-1, the final R = 0.0441 and wR = 0.1148 for 4200 observed reflections （Ⅰ 〉 2σ（Ⅰ））. In the molecule of the title complex, the asymmetric unit contains one half molecule, The Cu（Ⅱ） atom is five-coordinated by a tenninal water molecule, a bidentate phcnanthroline and two monodentate 4-ammobenzoate ligands forming a square pyramidal coordination environment. The two bridging 4-aminobenzoate ligands result in a dinuclear copper（Ⅱ） cluster with a short Cu-Cu distance （3.048 A） and a π-π rstacking between the adjacent phenanthroline rings （2.96 A）.

关键词： dinuclear copper(Ⅱ) phenanthroline 4-aminobenzonic acid crystal structure

Synthesis and Crystal structure of Poly{[Co(4,4'-bpy)(H_2O)_4]SO_(4·)(4-abaH)_(2·)3H_2O}

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Chinese Journal of Structural Chemistry 2005年第2期24卷 236-240页

作者： CHEN hong-ji jinan University Guangzhou510632China

The title complex has been obtained by the reaction of cobalt sulfate heptahydrate with 4,4?-bpy and 4-abaH (4,4?-bpy = 4,4?-bipyridine, 4-abaH = 4-aminobenzonic acid) in ethanol solution, and its structure was determined by X-ray crystallography with the following data: tetragonal, space group P42/n, Mr = 5692.46, Co8C192H288N32O120S8, a = b = 16.402(5), c = 22.750(5) ?, Z = 1, V = 6120(2) ?3, F(000) = 2968, Dc = 1.544 g/cm3, μ = 0.707 mm-1, the final R = 0.0786 and wR = 0.1935 for 2673 observed reflections (I > 2σ(I)). The title complex consists of polymeric [Co(4,4?-bipy)(H2O)4]2+ cation chains, SO4 2- anions, lattice 4-abaH and water mole- cules. The center CoII ions are connected by bridging 4,4?-bpy ligands exhibiting one-dimensional chains, and coordinated by four water molecules into a distorted octahedral geometry. These chains are further extended by hydrogen bonds among SO4 2- anions, coordinated and lattice water molecules as well as lattice 4-abaH molecules into a three-dimensional network.② Corresponding author. male, 48, associate professor, research interest in coordination chemistry. E-mail: thjchen@***② Corresponding author. male, 48, associate professor, research interest in coordination chemistry. E-mail: thjchen@***

关键词： self-assembly 4,4'-bipyridine 4-aminobenzonic acid crystal structure