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Biologically inspired collective construction with visual landmarks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第5期13卷 315-327页

作者： Zheng-wei zhan Hong zhanG yi-bin LI School of Control Science and Engineering Shandong University Jinan 250061 China Department of Computing Science University of Alberta Edmonton Alberta T6G 2E8 Canada

We describe our research in using environmental visual landmarks as the basis for completing simple robot construction *** by honeybee visual navigation behavior,a visual template mechanism is proposed in which a natural landmark serves as a visual reference or template for distance determination as well as for navigation during collective *** validate our proposed mechanism,a wall construction problem is investigated and a minimalist solution is *** results show that,using the mechanism of a visual template,a collective robotic system can successfully build the desired structure in a decentralized fashion using only local sensing and no direct *** addition,a particular variable,which defines tolerance for alignment of the structure,is found to impact the system *** decreasing the value of the variable,system performance is improved at the expense of a longer construction *** visual template mechanism is appealing in that it can use a reference point or salient object in a natural environment that is new or unexplored and it could be adapted to facilitate more complicated building tasks.

关键词： Biologically inspired Swarm robotics Collective construction Visual landmark Template

Electrodeposited Sulfur and CoxS Electrocatalyst on Buckypaper as High-Performance Cathode for Li-S Batteries

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Nano-Micro Letters 2020年第10期12卷 263-275页

作者： yi zhan Andrea Buffa Linghui Yu Zhichuan JXu Daniel Mandler School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Institute of Chemistry The Hebrew University of Jerusalem9190401 JerusalemIsrael Campus for Research Excellence and Technological Enterprise(CREATE) Singapore-HUJ Alliance for Research and Enterprise(SHARE)Singapore 138602Singapore

Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy *** this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotube buckypaper(S/CoxS/BP)by a facile electrodeposition method and are used as a binder-free high-performance cathode for *** sulfur is deposited on buckypaper by electrooxidation of a polysulfide solution(-S6^2-).This approach substantially increased the current and time efficiency of sulfur electrochemical deposition on conductive material for LSBs.S/CoxS/BP cathode could deliver an initial discharge capacity as high as 1650 mAh g^-1 at 0.1 C,which is close to the theoretical capacity of *** current rate of 0.5 C,the S/CoxS/BP has a capacity of 1420 mAh g^-1 at the first cycle and 715 mAh g^-1 after 500 cycles with a fading rate of 0.099%per *** high capacity of S/CoxS/BP is attributed to both the homogeneous dispersion of nanosized sulfur within BP and the presence of CoxS *** sodium dodecyl sulfate(SDS)pretreatment of BP renders it polarity to bind polysulfides and thus facilitates the good dispersibility of nanosized sulfur within *** catalyst accelerates the kinetics of polysulfide conversion and reduces the presence of polysulfide in the cathode,which suppresses the polysulfide diffusion to anode,i.e.,the shuttle *** mitigation of the active material loss improves not only the capacity but also the cyclability of S/CoxS/BP.

关键词： Electrodeposition Lithium sulfur batteries Buckypaper Electrocatalysts

Synthesis of ultrathin semicircle-shaped copper nanowires in ethanol solution for low haze flexible transparent conductors

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Nano Research 2018年第7期11卷 3899-3910页

作者： Ye zhan~ Jiangna Guo Dan Xu yi Sun Feng Yan Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application Department of Polymer Science and EngineeringCollege of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China

Copper nanowires （CuNWs） are becoming an indispensable item for next- generation transparent optical devices due to their excellent conductivity and transparency. In this work, ultrathin semicircle-shaped copper nanowires （SCuNWs） with a diameter of - 15 nm and a length of - 30 μm （aspect ratio of -2,000） were synthesized in ethanol solution. The mechanism and factors that affect the morphology and dispersity of the SCuNWs were investigated. The prepared SCuNWs were coated on polyethylene terephthalate （PET） or polyd- imethylsiloxane （PDMS） substrate to fabricate flexible transparent conductors （FTCs）. The fabricated FTCs exhibited excellent optoelectrical performance and low haze. In addition, the fabricated FTCs showed high mechanical stability during stretching and bending, indicating their great potential in flexible optical devices.

关键词： copper nanowires semicircle-shaped ultrathin low haze flexible transparent conductors

An adaptive method for high-resolution topology design

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Acta Mechanica Sinica 2013年第6期29卷 840-850页

作者： yi-Qiang Wang Jing-Jie He Zhen Luo zhan Kang State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology School of Electrical Mechanical and Mechatronic SystemsUniversity of TechnologySydneyNSW2007Australia National Engineering Research Center of Shipbuilding

For the purpose of achieving high-resolution optimal solutions this paper proposes a nodal design variablebased adaptive method for topology optimization of continuum structures. The analysis mesh-independent density field, interpolated by the nodal design variables at a given set of density points, is adaptively refined/coarsened accord- ing to a criterion regarding the gray-scale measure of local regions. New density points are added into the gray regions and redundant ones are removed from the regions occupied by purely solid/void phases for decreasing the number of de- sign variables. A penalization factor adaptivity technique is employed-to prevent premature convergence of the optimiza- tion iterations. Such an adaptive scheme not only improves the structural boundary description quality, but also allows for sufficient further topological evolution of the structural layout in higher adaptivity levels and thus essentially enables high-resolution solutions. Moreover, compared with the case with uniformly and finely distributed density points, the proposed adaptive method can achieve a higher numerical efficiency of the optimization process.

关键词： Topology optimization Adaptive method High resolution Nodal design variable Penalization factor adap fivity

Basic belief assignment approximations using degree of non-redundancy for focal element

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Chinese Journal of Aeronautics 2019年第11期32卷 2503-2515页

作者： yi YANG Deqiang han Jean DEZERT SKLSVMS School of AerospaceXi'an Jiaotong UniversityXi'an 710049China Center for Information Engineering Science Research XVan Jiaotong UniversityXi'an 710049China ONERA The French Aerospace LabChemin de la HunierePalaiseau F-91761France

Dempster-Shafer evidence theory, also called the theory of belief function, is widely used for uncertainty modeling and reasoning. However, when the size and number of focal elements are large, the evidence combination will bring a high computational complexity. To address this issue,various methods have been proposed including the implementation of more efficient combination rules and the simplifications or approximations of Basic Belief Assignments(BBAs). In this paper,a novel principle for approximating a BBA into a simpler one is proposed, which is based on the degree of non-redundancy for focal elements. More non-redundant focal elements are kept in the approximation while more redundant focal elements in the original BBA are removed first. Three types of degree of non-redundancy are defined based on three different definitions of focal element distance, respectively. Two different implementations of this principle for BBA approximations are proposed including a batch and an iterative type. Examples, experiments, comparisons and related analyses are provided to validate proposed approximation approaches.

关键词： BBA approximation Belief functions Evidence theory Focal element Non-redundancy

Further results on local stability of LRC-RED algorithm in Internet

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 99-103页

作者： zhan Zhen-qiu ZHU Jie SUN yi-Jin Department of Electronic Engineering Shanghai Jiao Tong UniversityShanghai 200240China

This paper presents some further results on the local stability of a recently developed Intemet congestion control scheme, namely the loss ratio and rate control random early detection （LRC-RED） algorithm. Necessary and sufficient stability conditions in terms of key tuning parameters are derived, which can provide further guidelines for control gain selection. The numerical simulations are given to illustrate the correctness of the theoretical analysis.

关键词： congestion control LRC-RED stability time delay system

Large deflection of curved elastic beams made of Ludwick type material

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Applied Mathematics and Mechanics(English Edition) 2017年第7期38卷 909-920页

作者： Hua LIU yi han Jialing YANG School of Aeronautic Science and Engineering Beihang University Beijing 100191 China

The large deflection of an axially extensible curved beam with a rectangular cross-section is investigated. The elastic beam is assumed to satisfy the Euler-Bernoulli postulation and be made of the Ludwick type material. Through reasonably simplified integration, the strain and curvature of the axis of the beam are presented in implicit formulations. The governing equations involving both geometric and material nonlin- earities of the curved beam are derived and solved by the shooting method. When the initial curvature of the beam is zero, the curved beam is degenerated into a straight beam, and the predicted results obtained by the present model are consistent with those in the open literature. Numerical examples are further given for curved cantilever and simply supported beams, and the couplings between elongation and bending are found for the curved beams.

关键词： large deflection curved beam Ludwick type material nonlinearity

Application of response surface methodology in optimizaing thesulfation-roasting-leaching process of nickel laterite

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International Journal of Minerals,Metallurgy and Materials 2012年第3期19卷 199-204页

作者： Xue-yi Guo Dong Li zhan Wu Qing-hua Tian School of Metallurgical Science and Engineering Central South UniversityChangsha 410083China

Nickel was recovered from nickel laterite using a sulfation-roasting-leaching process and the effects of operation parameters in- cluding acid addition, roasting temperature, and roasting time on nickel extraction and iron dissolution were investigated using response sur- face methodology （RSM）. Two second-order polynomial models of high significance were presented to show the relationship between the responses and the variables. The analysis of variance （ANOVA） showed high coefficients of determination （R2） of 0.894 and 0.980 for the two models, respectively. Optimum areas of 〉-80% Ni extraction and 〈5% Fe dissolution were obtained by the overlaid contours. Verification experiments in the optimum areas were conducted and the results indicate a close agreement with the predicted values obtained from the models.

关键词： nickel laterite sulfation roasting leaching optimization response surface methodology

The critical role of energetic fluctuations in charge separation for efficient molecular doping of organic semiconductors

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Science China Chemistry 2024年第11期67卷 3675-3680页

作者： Yan Zeng Guangchao han Yuanping yi Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Molecular doping is essential to improve the electrical conductivity of organic semiconductors for high-performance organic electronic devices. However, the doping efficiency is influenced by several factors, such as the energy levels, energetic fluctuations, dielectric properties, and molecular packing structures of the doped films, and the underlying mechanisms for highefficiency doping are still unclear. Here, through multi-level theoretical simulations on a series of fullerene derivatives, we identify that the energetic fluctuations can play a decisive role in activating charge separation for molecular doping. In particular,the doping efficiency appears to be exponentially increased with the fluctuation of charge polarization energies. Therefore,although the charge mobility is somewhat decreased, the experimental electrical conductivity is improved with the increased energetic fluctuation. Moreover, it has been found that polarization energy fluctuation can be effectively enhanced by simply introducing side chains with greater flexibility into organic semiconductors. This article paves the way towards high-efficiency molecular doping of organic semiconductors.

关键词： doping efficiency polarization energies energetic fluctuations organic semiconductors