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A Design of Single-Switch Two-Stage Dc-Dc converters With PWM And PFM for Off-Grid Solar Power System

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chinese Journal of Electrical Engineering 2017年第3期3卷 44-51页

作者： Junkai Zhao herbert h.c.iu Tyrone Fernando School of Electrical Electronic and Computer EngineeringThe University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia

In this paper,a single-switch two-stage Dc-Dc conversion circuit is proposed for an off-grid solar power application.A photovoltaic(PV)panel powers the load and a storage unit(battery)via the proposed circuit.The battery is designed to balance the supply and the demand of power under different irradiation situations.Based on conventional cascaded Dc-Dc converters,the proposed design is developed with the single switch technique reducing size,cost and power loss.The control scheme in this design is pulse width modulation(PWM)with pulse frequency modulation(PFM).The PWM module is similar to conventional design except its ramp signal with a variable frequency is provided by a resettable integrator.As a result,the PWM and PFM modules regulate the two stages of the proposed circuit separately with the same switching control signal.In this paper,the modes of operation of the circuit are discussed as well as the control schemes.The design process is described along with the circuit analysis and comparisons with conventional design are made as well.A prototype has been built to verify the proposed circuit with simulation and experimental results.

关键词： Single-switch technique photovoltaic power system off-grid solar system Dc-Dc conversion resettable integrator pulse frequency modulation(PWM) pulse width modulation(PFM)

Mutator for transferring a memristor emulator into meminductive and memcapacitive circuits

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chinese Physics B 2014年第7期23卷 366-376页

作者：于东升梁燕 herbert h.c.iu 胡义华 School of Information and Electrical Engineering China University of Mining and Technology School of Electrical Electronic and Computer EngineeringThe University of Western Australia School of Electronic and Electrical Engineering University of Strathclyde

In this paper, a concise but effective interface circuit for transforming a memristor into meminductive and memcapac- itive systems is designed. This newly proposed interface circuit, constructed by only two current conveyors, is equipped with three available ports, which can provide six connecting combinations in terms of one resistor, one capacitor, and one memristor. For the sake of confirming the design effectiveness, theoretical and simulation discussions are hence introduced and all the experimental waveforms provide conclusive evidence to validate the correctness of these new mutators. The most attractive features of this new interface circuit are the floating terminals and convenient practical implementation.

关键词： memristor meminductive memcapacitive self-excited oscillator

Fractional-order L_βc_a filter circuit network

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chinese Physics B 2015年第8期24卷 149-158页

作者：洪铮钱晶陈帝伊 herbert h.c.iu college of Electric Power Engineering Kunming University of Science and Technology Department of Electrical Engineering Northwest A & F University School of Electrical Electronic and Computer Engineering The University of Western Australia

In this paper we introduce the new fundamentals of the conventional Lc filter circuit network in the fractional domain.First, we derive the general formulae of the impedances for the conventional and fractional-order filter circuit network.Based on this, the impedance characteristics and phase characteristics with respect to the system variables of the filter circuit network are studied in detail, which shows the greater flexibility of the fractional-order filter circuit network in design.Moreover, from the point of view of the filtering property, we systematically study the effects of the filter units and fractional orders on the amplitude–frequency characteristics and phase–frequency characteristics. In addition, numerical tables of the cut-off frequency are presented. Finally, two typical examples are presented to promote the industrial applications of the fractional-order filter circuit network. Numerical simulations are presented to verify the theoretical results introduced in this paper.

关键词： fractional-order circuit,circuit networks,amplitude–frequency characteristics,phase–frequency characteristics

Implementation of an analogue model of a memristor based on a light-dependent resistor

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chinese Physics B 2012年第10期21卷 500-507页

作者：王晓媛 Andrew L.Fitch herbert h.c.iu Victor Sreeram 齐维贵 School of Electrical Engineering Harbin Institute of Technology School of Electrical Electronicand Computer EngineeringThe University of Western Australia 35 Stirling HighwayCrawleyWA 6009Australia

In this paper,an analogue model of a memristor using a light-dependent resistor(LDR) is presented.This model can be simplified into two parts:a control circuit and a variable resistor.It can be used to easily verify theoretical presumptions about the switching properties of memristors.This LDR-based memristor model can also be used in both simulations and experiments for future research into memristor applications.The paper includes mathematical models,simulations,and experimental results.

关键词： analogue model light-dependent resistor memristor simulator

A Prepaid Smart Metering Scheme Based on WiMAX Prepaid Accounting Model

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Smart Grid and Renewable Energy 2010年第2期1卷 63-69页

作者： Reduan h. Khan Tanzim F. Aditi Victor Sreeram herbert h. c. iu Bangladesh University of Engineering & Technology (BUET) University of Western Australia (UWA)

Prepaid energy meters have been widely adopted by utilities in different countries across the world as an innovative solution to the problem of affordability and consumption management. however, the present smart card based systems have some inherent problems like added cost, low availability and lack of security. In the future Smart Grid paradigm, use of smart meters can completely overhaul these prepaid systems by introducing centralized accounting, monitoring and credit-control functions using state-of-the-art telecommunication technologies like WiMAX. In this paper we pro-pose a prepaid smart metering scheme for Smart Grid application based on centralized authentication and charging using the WiMAX prepaid accounting model. We then discuss its specific application to Demand Response and Roam-ing of Electrical Vehicles.

关键词： Smart Metering WiMAX Smart Grid Demand Response Electric Vehicles

A Simpler Memristor Emulator Based on Varactor Diode

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chinese Physics Letters 2018年第5期35卷 144-147页

作者：于东升孙婷婷郑辞晏 h.h.c.iu T.Fernando School of Electrical and Power Engineering China University of Mining and Technology School of Electrical Electronic and Computer Engineering The University of Western Australia

A new memristor（MR） emulator is designed by making use of only three current-feedback operational amplifiers,one varactor diode, one capacitor and five resistors. As compared with other reported MR emulators, only three active devices and ten components in total are required for realizing this MR emulator, and hence this emulator can be regarded as a simpler one for the moment. The results obtained by Multisim simulation and experimental prototypes are given to verify the practicality and feasibility of this MR emulator.

关键词： MR As

A study of different annealing schedules in SARNA-predict A permutation based SA algorithm for RNA folding

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International Journal of Intelligent computing and cybernetics 2015年第2期8卷 152-171页

作者： herbert h.Tsang Kay c.Wiese Applied Research Lab Trinity Western UniversityLangleyCanada School of computing Science Simon Fraser UniversitySurreyCanada

Purpose–The purpose of this paper is to present a study of the effect of different types of annealing schedules for a ribonucleic acid(RNA)secondary structure prediction algorithm based on simulated annealing(SA).Design/methodology/approach–An RNA folding algorithm was implemented that assembles the final structure from potential substructures(helixes).Structures are encoded as a permutation of helixes.An SA searches this space of permutations.Parameters and annealing schedules were studied and fine-tuned to optimize algorithm performance.Findings–In comparing with mfold,the SA algorithm shows comparable results(in terms of F-measure)even with a less sophisticated thermodynamic model.In terms of average specificity,the SA algorithm has provided surpassing results.Research limitations/implications–Most of the underlying thermodynamic models are too simplistic and incomplete to accurately model the free energy for larger structures.This is the largest limitation of free energy-based RNA folding algorithms in general.Practical implications–The algorithm offers a different approach that can be used in practice to fold RNA sequences quickly.Originality/value–The algorithm is one of only two SA-based RNA folding algorithms.The authors use a very different encoding,based on permutation of candidate helixes.The in depth study of annealing schedules and other parameters makes the algorithm a strong contender.Another benefit is that new thermodynamic models can be incorporated with relative ease(which is not the case for algorithms based on dynamic programming).

关键词： Annealing schedule Simulated annealing RNA secondary structure prediction Ribonucleic acid RNA folding Permutation

Avian introgression in the genomic era

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Avian Research 2017年第4期8卷 181-191页

作者： Jente Ottenburghs Robert h.S.Kraus Pim van hooft Sipke E.van Wieren Ronald c.Ydenberg herbert h.T.Prins Resource Ecology Group Wageningen UniversityDroevendaalsesteeg 3a6708 PB WageningenThe Netherlands Department of Biology University of Konstanz78457 ConstanceGermany Department of Migration and Immuno-Ecology Max Planck Institute for OrnithologyAm Obstberg 178315 RadolfzellGermany centre of Wildlife Ecology Simon Fraser UniversityBurnabyBC V5A 1S6Canada

Introgression,the incorporation of genetic material from one(sub)species into the gene pool of another by means of hybridization and backcrossing,is a common phenomenon in birds and can provide important insights into the speciation process.In the last decade,the toolkit for studying introgression has expanded together with the development of molecular markers.In this review,we explore how genomic data,the most recent step in this methodological progress,impacts different aspects in the study of avian introgression.First,the detection of hybrids and backcrosses has improved dramatically.The most widely used software package is STRUcTURE.Phylogenetic discordance(i.***.different loci resulting in discordant gene trees) is another means for the detection of introgression,although it should be regarded as a starting point for further analyses,not as a definitive proof of introgression.Specifically,disentangling introgression from other biological processes,such as incomplete lineage sorting,remains a challenging endeavour,although new techniques,such as the D-statistic,are being developed.In addition,phylogenetics might require a shift from trees to networks.Second,the study of hybrid zones by means of geographical or genomic cline analysis has led to important insights into the complex interplay between hybridization and speciation.however,because each hybrid zone study is just a single snapshot of a complex and continuously changing interaction,hybrid zones should be studied across different temporal and/or spatial scales.A third powerful tool is the genome scan.The debate on which evolutionary processes underlie the genomic landscape is still ongoing,as is the question whether loci involved in reproductive isolation cluster together in ‘islands of speciation' or whether they are scattered throughout the genome.Exploring genomic landscapes across the avian tree of life will be an exciting field for further research.Finally,the findings from these different methods should be incorporated into specific speciation scena

关键词： Admixture cline theory D-statictic Genomic landscape hybridization Phylogenetic discordance

cyanobacterial flv4-2 Operon-Encoded Proteins Optimize Light harvesting and charge Separation in Photosystem Ⅱ

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Molecular Plant 2015年第5期8卷 747-761页

作者： Volha chukhutsina Luca Bersanini Eva-Mari Aro herbert van Amerongen Laboratory of Biophysics Wageningen University P.O. Box 8128 6700 ET Wageningen The Netherlands MicroSpectroscopy centre Wageningen University 6703HA Wageningen The Netherlands BioSolarcells P.O. Box 98 6700AB Wageningen The Netherlands Department of Biochemistry Molecular Plant Biology University of Turku FI-20014 Turku Finland These authors contributed equally to this article

Photosystem Ⅱ （PSII） complexes drive the water-splitting reaction necessary to transform sunlight into chemical energy. however, too much light can damage and disrupt PSlh In cyanobacteria, the flv4-2 operon encodes three proteins （FIv2, FIv4, and S110218）, which safeguard PSll activity under air-level cO2 and in high light conditions. however, the exact mechanism of action of these proteins has not been clarified yet. We demonstrate that the PSII electron transfer properties are influenced by the flv4-2 operon-encoded pro- teins. Accelerated secondary charge separation kinetics was observed upon expression/overexpression of the flv4-2 operon. This is likely induced by docking of the FIv2/FIv4 heterodimer in the vicinity of the QB pocket of PSlI, which, in turn, increases the QB redox potential and consequently stabilizes forward electron transfer. The alternative electron transfer route constituted by FIv2/FIv4 sequesters electrons from QB- guaranteeing the dissipation of excess excitation energy in PSII under stressful conditions. In addition, we demonstrate that in the absence of the flv4-2 operon-encoded proteins, about 20% of the phycobilisome antenna becomes detached from the reaction centers, thus decreasing light harvesting. Phycobilisome detachment is a consequence of a decreased relative content of PSII dimers, a feature observed in the absence of the SII0218 protein.

关键词： electron transfer flavodiiron proteins light harvesting photoprotection photosystem Ⅱ