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Advanced Solid State Lasers, ASSL 2015

作者： Talla, Alain F. Martinenghi, R. Woafo, Paul Larger, Laurent Chembo, Yanne K. Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes Department of Physics Faculty of Science P. O. Box 812 Yaoundé Cameroon Optics Department 16 Route de Gray Besançon Cedex25030 France

ISBN: (纸本)9781943580026

We investigate experimentally a novel optoelectronic oscillator based on a selfsustained oscillator that converts continuous light into stable and spectrally pure microwave in the intermediate frequency range. This optoelectronic oscillator is realized by replacing all of the electronic path of the optoelectronic encounter in the literature by self-sustained oscillators type of Van der Pol oscillator. A novel result is the presence of the "breathers" oscillations and the mixedmodes oscillations in the dynamics characterized by the laser injection current from the point of view of nonlinear dynamics, that is the "breathers inside the pulses packages ". This experimental result is obtained with or without delay line in the loop and the presence of delay induces chaos. © OSA 2015.

关键词： Optoelectronic devices

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Erratum to: Chaotic masking of communication in an emitter–relay–receiver electronic setup

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Nonlinear Dynamics 2016年第1期86卷 723-723页

作者： B. Nana P. Woafo Department of Physics Higher Teacher Training College University of Bamenda Bamenda Cameroon Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes Faculty of Science University of Yaounde I Yaounde Cameroon

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Numerical analysis of Goldschmied geometry with boundary-layer suction

Numerical analysis of Goldschmied geometry with boundary-lay...

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International Symposium on Underwater Technology

作者： Sudipta Ray Soumen Sen Dipankar Chatterjee Robotics & Automation CSIR-Central Mechanical Engineering Research Institute Durgapur India Simulation & Modelling Laboratory CSIR-Central Mechanical Engineering Research Institute Durgapur India

An effort is made to implement the phenomenon called the Aerodynamic Pressure Thrust (APT) for the purpose of effective propulsion of underwater vehicle. The two-dimensional Goldschmied body with boundary-layer ingestion near the stern section is considered for this purpose. This particular shape, which up to this point is being considered mainly for aerodynamic propulsion, can be preferred for autonomous underwater vehicles over conventional streamlined bodies for their large volume-to-length ratio. The wind-tunnel experiments of 1960's by Fabio R. Goldschmied paved a way for development of energy efficient propulsion through proper interaction of aerodynamic design and engine power. Decades later, this eventually led to the development of several futuristic crafts which exploit the Pressure Thrust technique. Similar idea is attempted here to obtain improved pressure recovery behind the aft of a blunt underwater vehicle to generate additional thrust. In the present study, a simplified version of the Goldschmied geometry is considered with a single slot for suction between the fore-body and the stern. The computations are carried out utilizing commercial CFD solver Ansys Fluent. The axi-symmetric shape of the Goldschmied body is employed to generate a fully-structured mesh throughout the entire domain. The simulations are carried out for a range of Reynolds number and the suction pressure. The distribution of pressure at different radial locations is examined and plotted, similar to the original work by Goldschmied, to illustrate the alternate zones of drag and thrust produced along the radius. A sizeable portion of the thrust region in the plot is required to overcome the drag force and to achieve self-propulsion solely by means of boundary layer suction. The results of the computational study indicate a trend in that direction.

关键词： Geometry Vehicles

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Evaluation for Voltage Stability Indices in Power System Using Artificial Neural Network

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Procedia engineering 2015年 118卷 1127-1136页

作者： H.H. Goh Q.S. Chua S.W. Lee B.C. Kok K.C. Goh K.T.K. Teo Department of Electrical Engineering Faculty of Electrical and Electronic Engineering Universiti Tun Hussein Onn Malaysia 86400 Parit Raja Batu Pahat Johor Malaysia Modelling Simulation and Computing Laboratory Level 3 Block C School of Engineering and Information Technology Universiti Malaysia Sabah Jalan UMS 88400 Kota Kinabalu Sabah Malaysia

At present, the evaluation of voltage stability assessment experiences sizeable anxiety in the safe operation of power systems. This is due to the complications of a strain power system. With the snowballing of power demand by the consumers and also the restricted amount of power sources, therefore, the system has to perform at its maximum proficiency. Consequently, the noteworthy to discover the maximum ability boundary prior to voltage collapse should be undertaken. A preliminary warning can be perceived to evade the interruption of power system's capacity. This paper considered the implementation of real-time system monitoring methods that able to provide a timely warning in the power system before the voltage collapse occurred. Numerous types of line voltage stability indices (LVSI) are differentiated in this paper to resolve their effectuality to determine the weakest lines for the power system. The line voltage stability indices are assessed using the IEEE 9-Bus and IEEE 14-Bus Systems to validate their practicability. Besides that, this paper also introduced the implementation of real-time voltage stability monitoring by using Artificial Neural Network (ANN). Results demonstrated that the calculated indices and the estimated indices by using ANN are practically relevant in predicting the manifestation of voltage collapse in the system. Therefore, essential actions can be taken by the operators in order to dodge voltage collapse incident from arising.

关键词： Artificial Neural Network (ANN) Line Voltage Stability Indices (LVSI) Maximum Loadability Voltage Stability Analysis

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Effects of springs on a pendulum electromechanical energy harvester

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Theoretical & Applied Mechanics Letters 2014年第6期4卷 73-79页

作者： Arnaud Notu Kadjie Paul Woafo Laboratory of Modelling and Simulation in Engineering Biomimetics and PrototypesDepartment of Physics Faculty of Science University of Yaound I YaoundCameroon

This paper studies a model of energy harvester that consists of an electromechanical pendulum system subjected to nonlinear springs. The output power is analyzed in terms of the intrinsic parameters of the device leading to optimal parameters for energy harvesting. It is found that in an appropriate range of the springs constant, the power attains higher values as compared to the case without springs. The dynamical behavior of the device shows transition to chaos.

关键词： energy harvester electromechanical pendulum optimal parameters transition to chaos

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3D CFD-DEM study of gas-solids flow and heat transfer in a full-loop circulating fluidized bed

3D CFD-DEM study of gas-solids flow and heat transfer in a f...

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11th International Conference on Fluidized Bed Technology, CFB 2014

作者： Wahyudi, H. Chu, K.W. Yu, A.B. Laboratory for Simulation and Modelling of Particulate Systems School of Materials Science and Engineering The University of New South Wales Sydney Australia

In this work, an extended CFD-DEM approach is developed to study the gas-solids flow and heat transfer between bed and riser wall in three-dimensional full-loop circulating fluidized bed. The effects of some operational, such as superficial gas velocity and solids inventory, on the heat transfer coefficient between bed and riser wall are investigated. The governing heat transfer modes such as wall-fluid convection, wall-particle conduction, are then discussed to gain better understanding about heat transfer between bed and wall in circulating fluidized beds. This work demonstrates that the developed 3D CFD-DEM approach could be a useful tool to study the coupled fluid flow and heat transfer in such a complex system.

关键词： Fluidization

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Cooling rate dependence of polymorph selection during rapid solidification of liquid metal zinc

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Transactions of Nonferrous Metals Society of China 2015年第12期25卷 4072-4079页

作者：田泽安周丽丽莫云飞梁永超刘让苏贵州大学大数据与信息工程学院贵阳550025 赣南医学院信息工程学院赣州341000 Laboratory for Simulation and Modelling of Particulate Systems School of Materials Science and Engineering University of New South Wales 湖南大学物理与微电子科学学院长沙410082

The polymorph selection during rapid solidification of zinc melt was investigated by molecular dynamics simulation. Several methods including g（r）, energy, CNS, basic cluster and visualization were used to analyze the results. The results reveal that the cooling rate has no observable effect on the microstructure as TTc（Tc is the onset temperature of crystallization）; and at the first stage of crystallization, although microstructures are different, the morphologies of nucleus are similar, which are composed of HCP and FCC layers; the polymorph selection of cooling rate finally takes place at the second stage of crystallization： at a high cooling rate, the rapid increase of FCC atoms leads to a FCC crystal mixed with less HCP structures; while at a low cooling rate, HCP atoms grow at the expense of FCC atoms, resulting in an almost perfect HCP phase. The results reveal that the cooling rate is one of the important factors for polymorph selection.

关键词： polymorph selection crystal structure rapid solidification metal zinc molecular dynamics simulation

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Experimental studies of segregation in gas fluidization of ellipsoidal particles

Experimental studies of segregation in gas fluidization of e...

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11th International Conference on Fluidized Bed Technology, CFB 2014

作者： Gan, Jieqing Xu, Yingbo Zhou, Zongyan Yu, Aibing Laboratory for Simulation and Modelling of Particulate Systems School of Materials Science and Engineering The University of New South Wales Sydney NSW 2052 Australia

In this work, segregation of non-spherical particles in gas fluidization is studied by physical experiments. The shapes considered are spheroids with aspect ratio varying from 0.1 to 5.0. It is revealed that binary mixtures of ellipsoids have a higher minimum fluidization velocity than mono-shaped ellipsoids. Segregation occurs in binary-shaped mixtures within a narrow gas velocity range and large shape difference. Initial packing conditions have negligible influence on the final segregation degree.

关键词： Binary mixtures

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Mixed-mode oscillations in slow-fast delayed optoelectronic systems

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Physical Review E 2015年第1期91卷 012902-012902页

作者： Jimmi H. Talla Mbé Alain F. Talla Geraud R. Goune Chengui Aurélien Coillet Laurent Larger Paul Woafo Yanne K. Chembo Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes University of Yaoundé I Department of Physics P.O. Box 812 Yaoundé Cameroon African Center of Excellence for Information and Communication Technologies (CETIC) Polytechnic School of Yaoundé P.O. Box 8390 Yaoundé Cameroon Optics Department 15B Avenue des Montboucons 25030 Besançon Cedex France

In this article, we investigate the dynamical behavior of breathers in optoelectronic oscillators from the standpoint of mixed-mode oscillations. In the phase space, these breathers are composite oscillations that are damped to the attractive branches of an invariant manifold. Our study shows that the emergence of breather dynamics is linked to the apparition of inflection points in the phase space, and we develop an analytical framework based on the Liénard reduction form in order to provide an analytical insight into this phenomenology. Our theoretical results are in excellent agreement with experimental measurements.

关键词： OPTOELECTRONICS OSCILLATIONS PHASE space (Statistical physics) PHENOMENOLOGY INVARIANT manifolds OPTICAL communications

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26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 Antwerp, Belgium. 15-20 July 2017 Abstracts

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BMC NEUROSCIENCE 2017年第SUPPL 1期18卷 95-176页

作者： [Anonymous] Department of Neuroscience Yale University New Haven CT 06520 USA Department Physiology & Pharmacology SUNY Downstate Brooklyn NY 11203 USA NYU School of Engineering 6 MetroTech Center Brooklyn NY 11201 USA Departament de Matemàtica Aplicada Universitat Politècnica de Catalunya Barcelona 08028 Spain Institut de Neurobiologie de la Méditerrannée (INMED) INSERM UMR901 Aix-Marseille Univ Marseille France Center of Neural Science New York University New York NY USA Aix-Marseille Univ INSERM INS Inst Neurosci Syst Marseille France Laboratoire de Physique Théorique et Modélisation CNRS UMR 8089 Université de Cergy-Pontoise 95300 Cergy-Pontoise Cedex France Department of Mathematics and Computer Science ENSAT Abdelmalek Essaadi’s University Tangier Morocco Laboratory of Natural Computation Department of Information and Electrical Engineering and Applied Mathematics University of Salerno 84084 Fisciano SA Italy Department of Medicine University of Salerno 84083 Lancusi SA Italy Dipartimento di Fisica Università degli Studi Aldo Moro Bari and INFN Sezione Di Bari Italy Data Analysis Department Ghent University Ghent Belgium Coma Science Group University of Liège Liège Belgium Cruces Hospital and Ikerbasque Research Center Bilbao Spain BIOtech Department of Industrial Engineering University of Trento and IRCS-PAT FBK 38010 Trento Italy Department of Data Analysis Ghent University Ghent 9000 Belgium The Wellcome Trust Centre for Neuroimaging University College London London WC1N 3BG UK Department of Electronic Engineering NED University of Engineering and Technology Karachi Pakistan Blue Brain Project École Polytechnique Fédérale de Lausanne Lausanne Switzerland Departement of Mathematics Swansea University Swansea Wales UK Laboratory for Topology and Neuroscience at the Brain Mind Institute École polytechnique fédérale de Lausanne Lausanne Switzerland Institute of Mathematics University of Aberdeen Aberdeen Scotland UK Department of Integrativ

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