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Recent advances on smart grid technology and renewable energy integration

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Science China(Technological Sciences) 2013年第12期56卷 3040-3048页

作者： mei ShengWei CHEN LaiJun State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University)

With the integration of renewable energy generations and other related changes,the smart grid,or the future electric power system,is confronted with new challenges and ***,it is a promising subject in electrical engineering and much work has been done on *** paper reviews the recent advances on the technologies of smart grid and renewable energy integration,from the aspects of modeling,simulation,protection and control,stability,operation,and planning.

关键词： smart grid renewable energy integration modeling simulation protection and control stability operation planning

Approximation for Counts of 2-runs in a Two State Markov Chain

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Acta Mathematica Sinica,English Series 2013年第10期29卷 1907-1916页

作者： Hui CHEN mei z.ang School of Mathematical Sciences Beijing Normal University

We consider a Markov chain X = {Xi, i = 1, 2,...} with the state space {0, 1}, and define W = ∑1=1^x XiXi＋1, which is the number of 2-runs in X before time n ＋ 1. In this paper, we prove that the negative binomial distribution is an appropriate approximation for LW when VarW is greater than EW. The error estimate obtained herein improves the corresponding result in previous literatures.

关键词： Negative binomial distribution head run Stein's method total variation distance cou-pling

Perfect Matching in k-partite k-graphs and 3-uniform HM-bipartite Hypergraphs

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Acta Mathematicae Applicatae Sinica 2020年第3期36卷 636-641页

作者： Chun-qiu Fang mei LU Department of Mathematical Sciences Tsinghua UniversityBeijing 100084China

Let H=(V,E)be an n-balanced k-partite k-graph with partition classes V1,...,*** for every legal(k-1)-tuple f contained in V\V1 and for every legal(k-1)-tuple g contained in V\Vk such that f∪g■E(H),we have d(f)+d(g)≥n+*** this paper,we prove that under this condition H must have a perfect *** result of this paper is about the perfect matching in 3-uniform hm-bipartite *** G be a 3-uniform hm-bipartite hypergraph with one of whose sides V1 has the size n,the another side V2 has size 2 *** for all the legal 2-tuple f with|f∩V1|=1 and for all the legal 2-tuple g with|g∩V1|=0,we have d(f)≥n-2 and d(g)>n/2,then G has a perfect matching.

关键词： Perfect matching k-partite k-graph hm-bipartite hypergraph

Holocene Climate Cycles in Northwest Margin of Asian Monsoon

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Chinese Geographical Science 2012年第4期22卷 450-461页

作者： LI Yu Wang Nai'ang LI zhuolun zHOU Xuehua z.ang Chengqi College of Earth and Environmental Sciences Center for Hydrologic Cycle and Water Resources in Arid RegionLanzhou UniversityLanzhou 730000China

In the mid-latitude regions of the Asian continent, zhuye Lake is located in the northwest margin of the Asian monsoon, where the modem climate is affected by the Asian monsoon and Westerlies. In this study, we investi- gated the absolutely dated Holocene records in zhuye Lake for detecting the Holocene climate cycles. Totally, 14 14C dates and 6 optically simulated luminescence （OSL） dates are obtained from the QTH01 and QTH02 sections. The proxies of grain-size, total organic carbon content （TOC）, C/N and 813C are used for wavelet analysis, and the results show obvious -256, -512 and -1024-year climate cycles, which are consistent with the Holocene millennial and cen- tennial scale climate cycles in the typical Asian summer monsoon domain. In different parts of the zhuye Lake, the Holocene sediments show variable climate cycles that are affected by the lake basin topography. In the zhuye Lake, the Holocene climate cycles are mainly correlated with the solar-related Asian summer monsoon variability and the North Atlantic ice-rafting events.

关键词： Holocene climate cycle Asian monsoon wavelet analysis zhuye Lake

Characterizations of semihoops based on derivations

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 291-310页

作者： Wang mei z.ang Xiao-hong School of Electrical and Control Engineering Shaanxi University of Science and TechnologyXi'an 710021China School of Arts and Sciences Shaanxi University of Science and TechnologyXi'an 710021China School of Mathematics and Statistics Weinan Normal UniversityWeinan 714099China

In this paper,we discuss the related properties of some particular derivations in semihoops and give some characterizations of ***,we prove that every Heyting algebra is isomorphic to the algebra of all multiplicative derivations and show that every Boolean algebra is isomorphic to the algebra of all implicative ***,we show that the sets of multiplicative and implicative derivations on bounded regular idempotent semihoops are in oneto-one correspondence.

关键词： (prelinear)semihoop derivation Heyting algebra Galois connection

Modeling and Analysis of Matthew Effect Under Switching Social Networks via Distributed Competition

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IEEE/CAA Journal of Automatica Sinica 2022年第7期9卷 1311-1314页

作者： mei Liu Suibing Li Long Jin School of Information Science and Engineering Lanzhou UniversityLanzhou 730000 State Key Laboratory of Tibetan Intelligent Information Processing and Application Xining 810016China IEEE

Dear editor,This letter models and analyzes the Matthew effect under switching social networks via distributed competition.A competitive strategy is leveraged to trace the evolution of individuals in social systems under the Matthew *** addition,a consensus filter is utilized to decentralize the model with undirected graphs used to describe the interactions among individuals in social ***,a term is added to the dynamic consensus filter to compensate for the influence of the switching of communication networks on the *** this letter,the convergence of the proposed Matthew effect model is theoretically proved,and simulative experiments are conducted to verify the availability of the *** particular,this letter points out the state and evolution of each individual in social systems with distributed competition,and the influence of the social environment on the development of individuals is also intuitively displayed.

关键词： effect. letter intuitive

Dependence on forming parameters of an integral panel during the electromagnetic incremental forming process

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Chinese Journal of Aeronautics 2018年第7期31卷 1625-1634页

作者： Jinqiang TAN mei zHAN Hongwei LI State Key Laboratory of Solidification Process School of Materials Science & Engineering Northwestern Polytechnical University

Nowadays, more and more attentions are paid to electromagnetic incremental forming（EMIF）, especially for a part with a large-scale size, e.g., an integral panel with stiffened ribs. In this work, the bending of a panel into a double-curvature profile via EMIF is carried out experimentally and evaluated by comparing the formed profile with the desired profile. During the process,discharges at four positions along different discharge paths are designed. The effects of forming parameters on the die-fittingness of the workpiece are discussed, for which two evaluation indices are used to judge forming results. The results show that a discharge voltage in an incremental mode is helpful to improve the fittingness and avoid the collision rebound against the die at the same *** at the diagonal positions with the ‘‘X＂ discharge path exhibits the minimal shape deviation and the best forming uniformity. On the contrary, discharging at the parallel positions with the ‘‘z＂ discharge path obtains the worst forming quality. Overlap of the coil at different positions should be given during EMIF; however, a lower overlap rate of the coil helps improve the forming quality. The results obtained in this work are useful for forming integral panels with stiffened ribs via the EMIF process.

关键词： Electromagnetic incrementalforming (EMIF) Forming uniformity Integral panel Parameters Shape deviation

Controller Parameter Tuning of Delta Robot Based on Servo Identification

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Chinese Journal of Mechanical Engineering 2015年第2期28卷 267-275页

作者： zHAO Qing Wang Panfeng mei Jiangping Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin University

High-speed pick-and-place parallel robot is a system where the inertia imposed on the motor shafts is real-time changing with the system *** quality of computer control with proper controller parameters is conducive to overcoming this problem and has a significant effect on reducing the robot＇s tracking *** taking Delta robot as an example,a method for parameter tuning of the fixed gain motion controller is *** identifying the parameters of the servo system in the frequency domain by the sinusoidal excitation,the PD＋feedforward control strategy is proposed to adapt to the varying inertia loads,allowing the controller parameters to be tuned by minimizing the mean square tracking error along a typical trajectory.A set of optimum parameters is obtained through computer simulations and the effectiveness of the proposed approach is validated by experiments on a real prototype *** the traveling plate undergoes a specific trajectory and the results show that the tracking error can be reduced by at least 50%in comparison with the conventional auto-tuning and z-N *** proposed approach is a whole workspace optimization and can be applied to the parameter tuning of fixed gain motion controllers.

关键词： parallel robot servo system identification parameter tuning mean square error

Synthesis and Structure of a Manganese(Ⅱ) Complex: [Mn_2·(dinitrobenzoic acid)_4·(1,10-phen)_2]_n

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Chinese Journal of Structural Chemistry 2007年第2期26卷 139-142页

作者： Wang Jian HUang mei-Hua LIU Ping CHENG Wen-Dan z.ang Li-mei Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China 不详

The title compound, [Mn2·（dinitrobenzoic acid）4·（1,10-phen）2]n, has a linear chain structure containing binuclear [Mn2·（dinitrobenzoic acid）4（1,10-phen）2] repeat units. It crystallizes in the triclinic system, space group Pi with a = 7.9261（8）, b = 12.1329（15）, c = 14.847（2）A, α = 103.845（5）, β = 101.424（5）, γ = 92.618（4）°, Mr= 657.37, V = 1352.3（2）A^3, z = 2, De= 1.614 g/cm^3, F（000） = 666,μ = 0.567 mm^-1, the final R = 0.0407 and wR = 0.1015 for 4081 observed reflections with I 〉 2σ（I）. The Mn atom is six-coordinated by two N and four O atoms, forming a slightly distorted octahedral geometry. All Mn-O and Mn-N bond distances range from 2.093（2） to 2.310（2）A. Two adjacent octahdral units are bridged together by two pairs of bi-monodentate carboxyl groups of different dinitrobenzoic acids to form an eight-membered ring with chair-typed configuration, thus generating a one-dimensional chain along the a axis.

关键词： crystal structure manganese complex eight-membered ring one-dimensional chain