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Finite-time adaptive consensus of a class of multi-agent systems

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Science China(Technological Sciences) 2016年第1期59卷 22-32页

作者： lIU Kexin wu lulu lü JinHu ZHU HengHui Academy of Mathematics and Systems Science Chinese Academy of Sciences

Multi-agent systems(MASs) are ubiquitous in natural and artificial systems. This paper aims to establish the finite-time adaptive consensus criterion for a class of MASs with nonlinear dynamics. Traditionally, the finite-time consensus criterion is often established based on the prior information on lipschitz constants and the eigenvalues of laplacian matrix. However, it is difficult to acquire the above prior information for most real-world engineering systems. To overcome the above difficulty, this paper develops the finite-time consensus criteria for a class of MASs with nonlinear dynamics via adaptive technique. In detail, we design the finite-time distributed node-based and edge-based adaptive consensus protocols for a class of MASs with fixed and switching topologies. Numerical simulations are also given to validate the proposed finite-time adaptive consensus criterion.

关键词： Multi-agent systems adaptive control finite-time consensus switching topology

Collective radiance of giant atoms in non-Markovian regime

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Science China(Physics,Mechanics & Astronomy) 2023年第2期66卷 79-86页

作者： Qing-Yang Qiu Ying wu xin-You lü School of Physics Huazhong University of Science and TechnologyWuhan 430074China

We investigate the non-Markovian dynamics of two giant artificial atoms interacting with a continuum of bosonic modes in a onedimensional(1D) *** on the diagrammatic method,we present the exact analytical solutions,which predict the rich phenomena of collective *** the certain collective states,the decay rates are found to be far beyond that predicted in the the Dicke model and standard Markovian framework,which indicates the occurrence of *** superadiance-to-subradiance transition could be realized by adjusting the exchange symmetry of giant ***,there exist multiple bound states in continuum(BICs),with photons/phonons bouncing back and forth in the cavity-like geometries formed by the coupling *** trapped photons/phonons in the BICs can also be re-released conveniently by changing the energy level splitting of giant *** mechanism relies on the joint effects of the coherent time-delayed feedback and the interference between the coupling points of giant *** work fundamentally broadens the fields of giant atom collective radiance by introducing *** also paves the way for a clean analytical description of the nonlinear open quantum system with more complex retardation.

关键词： collective symmetry conveniently

AN IN-SITU STUDY ON DISlOCATION BEHAVIOR OF CRACK-TIP IN Ti_3Al-Nb AllOY

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中国有色金属学会会刊：英文版 1997年第3期7卷 31-37页

作者： wu, Y Zhen, l Yang, DZ liang, W HARBIN INST TECHNOl SCH MAT SCI & ENGN HARBIN 150001 PEOPLES R CHINA TAIYUAN UNIV TECHNOl DETECTING CTR TAIYUAN 030024 PEOPLES R CHINA

ＡＮＩＮＳＩＴＵＳＴＵＤＹＯＮＤＩＳＬＯＣＡＴＩＯＮＢＥＨＡＶＩＯＲＯＦＣＲＡＣＫＴＩＰＩＮＴｉ３ＡｌＮｂＡＬＬＯＹ①ＷｕＹｉｎｇ，ＺｈｅｎＬｉａｎｇ，ＹａｎｇＤｅｚｈｕａｎｇＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓ... 详细信息

ＡＮＩＮＳＩＴＵＳＴＵＤＹＯＮＤＩＳＬＯＣＡＴＩＯＮＢＥＨＡＶＩＯＲＯＦＣＲＡＣＫＴＩＰＩＮＴｉ３ＡｌＮｂＡＬＬＯＹ①ＷｕＹｉｎｇ，ＺｈｅｎＬｉａｎｇ，ＹａｎｇＤｅｚｈｕａｎｇＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｒ...

关键词： Ti 3Al Nb alloy tensile deformation crack propagation dislocation

Orbit configuration spaces of small covers and quasi-toric manifolds

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Science China Mathematics 2021年第1期64卷 167-196页

作者： Junda Chen Zhi lü Jie wu School of Mathematical Sciences Fudan UniversityShanghai200433China Department of Mathematics National University of SingaporeSingapore119260Republic of Singapore

In this article,we investigate the orbit configuration spaces of some equivariant closed manifolds over simple convex polytopes in toric topology,such as small covers,quasi-toric manifolds and(real)moment-angle manifolds;especially for the cases of small covers and quasi-toric *** kinds of orbit configuration spaces have non-free group actions,and they are all noncompact,but still built via simple convex *** obtain an explicit formula of the Euler characteristic for orbit configuration spaces of small covers and quasi-toric manifolds in terms of the h-vector of a simple convex *** a by-product of our method,we also obtain a formula of the Euler characteristic for the classical configuration space,which generalizes the Félix-Thomas *** addition,we also study the homotopy type of such orbit configuration *** particular,we determine an equivariant strong deformation retraction of the orbit configuration space of 2 distinct orbit-points in a small cover or a quasi-toric manifold,which allows to further study the algebraic topology of such an orbit configuration space by using the Mayer-Vietoris spectral sequence.

关键词： orbit configuration space small cover quasi-toric manifold (real)moment-angle manifold Euler characteristic homotopy type

An insight into Mg alloying effects on Cu thin films:microstructural evolution and mechanical behavior

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Journal of Materials Science & Technology 2020年第22期54卷 101-112页

作者： G.Y.li l.F.Cao J.Y.Zhang x.G.li Y.Q.Wang K.wu G.liu J.Sun State Key laboratory for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'an710049China International Joint laboratory for light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Electron Microscopy Center of Chongqing University Chongqing UniversityChongqing400044China

How to design ultra-strong,light-weight Cu alloys is a long-term pursuit in materials community,which is technically superior and cost-effective for their promising energy-saving *** this work,we prepared Cu-Mg alloyed thin films to study light element Mg alloying effects on the microstructure,hardness and strain rate sensitivity(SRS) of nanocrystalline Cu thin *** the studied Mg concentrationrange spanning from 0 at.% to 16.8 at.%,both the grain size and the twin spacing decrease monotonously with increasing Mg composition while Cu-2.8 at.% Mg sample has the highest twin fraction of ~75%.A combined strengthening model was employed to quantify the Mg concentration-dependent hardness of nanotwinned(NT) Cu-Mg thin films,in which the grain/twin boundary facilitates strengthening while the solute Mg atoms induce *** the constant rate of loading tests and the nanoindentation creep tests uncover that compared with pure Cu samples,the NT Cu-Mg thin films manifest much lower SRS,particularly in the creep tests,owing to the activation of dynamic strain aging effects.

关键词： Cu-Mg thin films Microstructure evolution Creep tests Hardness Strain rate sensitivity

Chemical characteristics of rainwater in karst rural areas,Guizhou Province, Southwest China

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Acta Geochimica 2017年第3期36卷 572-576页

作者： Pin lü Guilin Han Qixin wu School of Water Resources and Environment China University of Geosciences (Beijing) Key laboratory of Karst Environment and Geohazard Ministry of Land and Resources Guizhou University

The chemical composition of rainwater has been studied in a karst rural area from September 2012 to August 2013 in Guizhou Province,Southwest *** results indicated that the VWM value of p H was 5.4,varied from 4.6 to ***^(2+)and NH_4^+were the major cations,and SO_4^(2-)was the dominant *** factors show that the acid was mainly neutralized by Ca^(2+),NH_4^+and Mg^(2+).Investigations of correlation coefficients and enrichment factors revealed that Ca^(2+)and Mg^(2+)were mainly crust origins,and NH_4^+was from agriculture and livestock ***_4^(2-)and NO_3^-were mainly from anthropogenic sources.

关键词： Chemical composition Rainwater Karst rural area Southwest China

Spectral and Timing Analysis of the Black Hole Transient MAxI J1631–479 During its 2019 Outburst Observed with Insight-HxMT

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Research in Astronomy and Astrophysics 2022年第11期22卷 21-33页

作者： Yu-Cong Fu l.M.Song G.Q.Ding S.N.Zhang J.l.Qu S.Zhang l.Zhang Q.C.Bu Y.Huang x.Ma Z.x.Yang Y.l.Tuo x.F.lu D.K.Zhou B.Y.wu T.M.li Y.C.xu xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqiXinjiang 830011China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Key laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Institut fur Astronomie und Astrophysik Kepler Center for Astro and Particle PhysicsEberhard Karls UniversitatSand 1D-72076 TübingenGermany

We report spectral and timing analysis of the black hole transient MAxI J1631–479 during the hard intermediate state of its 2019 outburst from the Insight-Hard x-ray Modulation Telescope(Insight-HxMT)*** find that the energy dependence of the type-C quasi-periodic oscillation(QPO)frequency evolves with time:during the initial rise of a small flare(~MJD 58526.0-58527.1),the QPO frequency increases with increasing energy from~1 to~100 ke V,and then the frequency remains constant after MJD *** discover a possible new phenomenon of Fe line’s QPO frequency jump that has never been observed for other black hole transients:during the small flare,the QPO frequency around the Fe line energy is higher than any other energy band,with the frequency difference Δf=0.25±0.08 Hz between 5.5–7.5 ke V and other energy *** spectral analysis shows that the evolution of QPOs is related to the equivalent width of the narrow Fe line,and its equivalent width increases during this small *** propose that the QPO frequency difference results from the differential precession of a vertically extended jet,and the higher QPO frequency of Fe line could be caused by the layered jet when the jet scale *** the same time,the evolution of QPOs is related to the accretion rate,while the energy dependence of QPOs supports the existence of deceleration in the vertically distributed jet.

关键词： accretion accretion disks stars:black holes x-rays:binaries

An h-adaptive Discontinuous Galerkin Method for laminar Compressible Navier-Stokes Equations on Curved Mesh

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第5期33卷 566-575页

作者： Sun Qiang l yu Hongqiang wu Yizhao College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 P.R. China

An h-adaptive method is developed for high-order discontinuous Galerkin methods(DGM)to solve the laminar compressible Navier-Stokes(N-S)equations on unstructured *** vorticity is regarded as the indicator of *** elements where the vorticity is larger than a pre-defined upper limit are refined,and those where the vorticity is smaller than a pre-defined lower limit are coarsened if they have been refined.A high-order geometric approximation of curved boundaries is adopted to ensure the *** results indicate that highly accurate numerical results can be obtained with the adaptive method at relatively low expense.

关键词： h-adaptivity high-order discontinuous Galerkin methods(DGM) N-S equations high-order boundary approximation

Effects of hydraulic retention time, temperature, and effluent recycling on efficiency of anaerobic filter in treating rural domestic wastewater

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Water Science and Engineering 2014年第2期7卷 168-182页

作者： John leju Celestino lADU xi-wu lü School of Energy and Environment Southeast University College of Natural Resources and Environmental Studies University of Juba

With rural population expansion and improvement of the socio-economic standard of living, treatment of rural domestic wastewater has rapidly become a major aspect of environmental concern. Selection of a suitable method for treatment of rural domestic wastewater depends on its efficiency, simplicity, and cost-effectiveness. This study investigated the effects of hydraulic retention time （HRT）, temperature, and effluent recycling on the treatment efficiency of an anaerobic filter （AF） reactor. The first round of experimental operations was run for three months with HRTs of one, two, and three days, temperatures of 18℃, 21℃, and 24℃, and no effluent recycling. The second round of experimental operations was conducted for another three months with HRTs of three and four days; temperatures of 30.67℃, 30.57℃, and 26.91 ℃ ; and three effluent recycling ratios of 1：1, 1：2, and 2：1. The first round of operations showed removal rates of 32% to 44% for COD, 30% to 35% for TN, 32% to 36% for NH4-N, 19% to 23% for NO3-N, and 12% to 22% for TE In the second round of operations, the removal rates varied from 75% to 81% for COD, 35% to 41% for TN, 31% to 39% for NH4-N, 30% to 34% for NO3-N, and 41% to 48% for TP. The average gas production rates were 6.72 l/d and 7.26 l/d for the first and second rounds of operations, respectively. The gas production rate increased in the second round of operations as a result of applied effluent recycling. The best removal efficiency was obtained for an optimum HRT of three days, a temperature of 30℃, and an effluent recycling ratio of 2：1. The results show that the removal efficiency of the AF reactor was affected by HRT, temperature, and effluent recycling.

关键词： anaerobic filter (AF) rural domestic wastewater hydraulic retention time (HRT) effluent recycling experimental operation