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Exciton recycling via InP quantum dot funnels for luminescent solar concentrators

Nano Research 2021年第5期14卷 1488-1494页

作者： Houman Bahmani Jalali Sadra Sadeghi Isinsu Baylam Mertcan Han Cleva W.Ow-Yang Alphan Sennaroglu Sedat Nizamoglu Graduate School of Biomedical Sciences and Engineering KoçUniversityIstanbul34450Turkey Graduate School of Material Science and Engineering KoçUniversityIstanbul34450Turkey koçuniversity Surface Science and Technology Center(KUYTAM) KoçUniversityIstanbul34450Turkey Laser Research Laboratory KoçUniversityIstanbul34450Turkey Department of Electrical and Electronics Engineering KoçUniversityIstanbul34450Turkey Department of Material Science and Nano Engineering Sabanci UniversityIstanbul34956Turkey

Luminescent solar concentrators (LSC) absorb large-area solar radiation and guide down-converted emission to solar cells for electricity production. Quantum dots (QDs) have been widely engineered at device and quantum dot levels for LSCs. Here, we demonstrate cascaded energy transfer and exciton recycling at nanoassembly level for LSCs. The graded structure composed of different sized toxic-heavy-metal-free InP/ZnS core/shell QDs incorporated on copper doped InP QDs, facilitating exciton routing toward narrow band gap QDs at a high nonradiative energy transfer efficiency of 66%. At the final stage of non-radiative energy transfer, the photogenerated holes make ultrafast electronic transitions to copper-induced mid-gap states for radiative recombination in the near-infrared. The exciton recycling facilitates a photoluminescence quantum yield increase of 34% and 61% in comparison with semi-graded and ungraded energy profiles, respectively. Thanks to the suppressed reabsorption and enhanced photoluminescence quantum yield, the graded LSC achieved an optical quantum efficiency of 22.2%. Hence, engineering at nanoassembly level combined with nonradiative energy transfer and exciton funneling offer promise for efficient solar energy harvesting.

关键词： energy transfer indium phosphide quantum dot light harvesting luminescent solar concentrator luminescent solar concentrators(LSC)

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Iterative signal reconstruction of deliberately clipped SMT signals

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Science China(Information Sciences) 2014年第2期57卷 5-17页

作者： koLLR Zsolt GAZDA Juraj HORVTH Pter VARGA Lajos koCUR Duan Budapest university of Technology and Economics Technical university of koice

Staggered MultiTone(SMT)is a modulation technique showing significantly reduced Adjacent Channel Leakage Ratio(ACLR)resulting in a more compact Power Spectrum Density(PSD)for the transmitted signal,than the well-known and already widely adopted Orthogonal Frequency Division Multiple Access(OFDMA)***,the unique spectral properties of an SMT signal could be degraded by a non-linear element(e.g.a Power Amplifier(PA))in the *** baseband clipping can be applied to the transmitted signal,reducing the notable high Peak-to-Average Power Ratio(PAPR).The objective of this paper is to give a brief introduction to the SMT scheme,with a special emphasis on deliberate clipping efects and their *** paper introduces two receiver-oriented iterative methods aiming at the restoration of the baseband Bit Error Rate(BER)performance of a non-clipped *** methods are evaluated and compared based on numerical *** paper concludes with the selection of a possible candidate for use in systems applying deliberately clipped SMT signals.

关键词： clipping SMT iterative decoding nonlinear distortion PAPR

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Interactive transport of multi-view videos for 3DTV applications

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2006年第5期7卷 830-836页

作者： KURUTEPE Engin CIVANLAR M.Reha TEKALP A.Murat School of Engineering ko university Istanbul 34450 Turkey

The authors propose a novel method for transporting multi-view videos that aims to keep the bandwidth requirements on both end-users and servers as low as possible. The method is based on application layer multicast, where each end point re- ceives only a selected number of views required for rendering video from its current viewpoint at any given time. The set of selected videos changes in real time as the user’s viewpoint changes because of head or eye movements. Techniques for reducing the black-outs during fast viewpoint changes were investigated. The performance of the approach was studied through network experiments.

关键词： 3DTV, Multi-view video, Application-layer multicast, Join-latency

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Preparation and Compaction Behaviour of Poly(methyl methacrylate) Coated Iron Microparticles

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Journal of Materials Science & Technology 2010年第5期26卷 454-460页

作者： Daniela Kladeková Renáta Orináková Annamária Krajníková Miriam Kupková Margita Kabátová Kveta Markuová Institute of Chemistry Faculty of ScienceP.J.afárik University in Koice Institute of Materials Research of the Slovak Academy of Sciences in koice

The poly（methyl methacrylate）（PMMA） coatings onto surface of iron particles were electrochemically prepared and the effect on both surface structure and internal structure of the resulted material after compaction was carried *** electrochemical polymerization treatment was performed in a fluidized bed electrolyzer using sulphuric acid solution containing potassium persulphate and methyl methacrylate（MMA）.The surface topography and the microstructure of the samples were observed by scanning electron microscopy（SEM） and optical microscopy（OM）.It was found that the PMMA layer coated onto iron particles results in improvement of their compressibility compared with uncoated powders,and classical lubricants are not necessary for compacting particles coated.

关键词： Cathodic electropolymerization Poly(methyl methacrylate) coating Surface appearance Microstructure Compaction process

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Advantageous mechanochemical synthesis of copper(Ⅰ)selenide semiconductor,characterization,and properties

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Frontiers of Chemical Science and Engineering 2022年第3期16卷 433-442页

作者： Katarína Gáborová Marcela Achimovičová Michal Hegedüs Vladimír Girman Mária Kaňuchová Erika Dutková Institute of Geotechnics Slovak Academy of SciencesKošice04001Slovakia Institute of Metallurgy Faculty of MaterialsMetallurgy and RecyclingTechnical UniversityKošice04201Slovakia Synthon s.r.o.Blansko67801Czech Republic Faculty of Science Pavol JozefŠafárik UniversityKošice04154Slovakia Institute of Earth Resources Faculty of MiningEcologyProcess Control and GeotechnologiesTechnical UniversityKošice04200Slovakia

Copper(I)selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball *** kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se *** X-ray diffraction confirmed the orthorhombic crystal structure of Cu_(2)Se with the crystallite size∼25 *** surface chemical structure was studied by X-ray photoelectron spectroscopy,whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu^(+)and Se^(2−)oxidation *** electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure,as *** optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence *** direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size *** type of Cu_(2)Se synthesis can be easily adapted to production dimensions using an industrial vibratory *** advantages of mechanochemical synthesis represent the potential for inexpensive,environmentally-friendly,and waste-free manufacturing of Cu_(2)Se.

关键词： Cu_(2)Se berzelianite nanocrystalline semiconductor mechanochemical synthesis planetary ball mill

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Cross-Context News Corpus for Protest Event-Related Knowledge Base Construction

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Data Intelligence 2021年第2期3卷 308-335页

作者： Ali Hürriyetoglu Erdem Yörük Osman Mutlu Fırat Durusan ÇagrıYoltar Deniz Yüret Burak Gürel koçuniversity Rumelifeneri yoluSariyerIstanbul 34450Turkey

We describe a gold standard corpus of protest events that comprise various local and international English language sources from various *** corpus contains document-,sentence-,and token-level *** corpus facilitates creating machine learning models that automatically classify news articles and extract protest event-related information,constructing knowledge bases that enable comparative social and political science *** each news source,the annotation starts with random samples of news articles and continues with samples drawn using active *** batch of samples is annotated by two social and political scientists,adjudicated by an annotation supervisor,and improved by identifying annotation errors *** found that the corpus possesses the variety and quality that are necessary to develop and benchmark text classification and event extraction systems in a cross-context setting,contributing to the generalizability and robustness of automated text processing *** corpus and the reported results will establish a common foundation in automated protest event collection studies,which is currently lacking in the literature.

关键词： Event extraction Text classification Political science Social science News Contentious politics Protests Event coreference resolution

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Joins of 1-Planar Graphs

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Acta Mathematica Sinica,English Series 2014年第11期30卷 1867-1876页

作者： Július CZAP Dvid HUDK Tom MADARAS Department of Applied Mathematics and Business Informatics Faculty of Economics Technical University of KoiceNěmcovej 32040 01 KoiceSlovakia VSL Software a.s.Lomen 8040 01 KoiceSlovakia Institute of Mathematics Faculty of SciencePavol Jozef afrik University Jesenn 5040 01 KoiceSlovakia

A graph is called 1-planar if it admits a drawing in the plane such that each edge is crossed at most *** this paper,we study 1-planar graph *** prove that the join G ＋ H is 1-planar if and only if the pair [G,H] is subgraph-majorized by one of pairs [C3 ∪ C3,C3],[C4,C4],[C4,C3],[K2,1,1,P3] in the case when both elements of the graph join have at least three *** one element has at most two vertices,then we give several necessary/sufficient conditions for the bigger element.

关键词： 1-Planar graph join product

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Effect of Varying Carbon Content and Shot Peening upon Fatigue Performance of Prealloyed Sintered Steels

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Journal of Materials Science & Technology 2009年第5期25卷 607-610页

作者： R.Bidulsky M.Actis-Grande M.Kabtov J.Bidulsk Politecnico Torino Alessandria CampusV.T.Michel5Alessandria 15000Italy Institute of Materials Research SASWatsonova 47Koice04011Slovakia Technical university of koice Faculty of MetallurgyLetn9Koice 04200Slovakia

The aim of the work was to find out how the modification of surface treatment and microstructures affect the fatigue characteristics of the considered sintered materials. Two different systems were prepared： as-sintered and shot peened prealloyed sintered （Astaloy CrL based） steels with addition of 0.5% and 0.7% C. Sintering was carried out in laboratory tube furnace in an atmosphere of pure gases 75%N2＋25%H2. The sintering temperature was 1180℃ and sintering time was 60 min. Heating and cooling rates were 10℃/min. Fatigue tests were carried out in symmetric plane bending at stress ratio R=-1 with frequency of about 24 Hz. The presented experimental results showed that prealloyed water-atomised steels, with surface modification, exhibit positive effects on the fatigue failure resistance, and for that reason are suitable for high-performance applications.

关键词： Sintered steels Shot peening Fatigue strength S-N curves

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ON(a,b)-CONSECUTIVE PETERSEN GRAPHS

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Acta Mathematicae Applicatae Sinica 1998年第3期14卷 265-270页

作者： MArgIN BAcA IVAN HOLLANDER(Department of Mathematics, Technical university, kosice, Slovakia) Department of Mathematics Technical University Košice Slovakia

The generalized Petersen graphs p(n,k) n≥3, 1≤k 详细信息

The generalized Petersen graphs p(n,k) n≥3, 1≤k

关键词： Generalized Petersen graphs (a,b)-consecutive labeling (a,b)-consecutive graph

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An Effective Classifier Model for Imbalanced Network Attack Data

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Computers, Materials & Continua 2022年第12期73卷 4519-4539页

作者： Gürcan Ctin Department of Information System Engineering Mugla SıtkıKo鏼an UniversityMugla48000Turkey

Recently,machine learning algorithms have been used in the detection and classification of network *** performance of the algorithms has been evaluated by using benchmark network intrusion datasets such as DARPA98,KDD’99,NSL-KDD,UNSW-NB15,and Caida ***,these datasets have two major challenges:imbalanced data and highdimensional *** high accuracy for all attack types in the dataset allows for high accuracy in imbalanced *** the other hand,having a large number of features increases the runtime load on the algorithms.A novel model is proposed in this paper to overcome these two *** number of features in the model,which has been tested at CICIDS2017,is initially optimized by using genetic *** optimum feature set has been used to classify network attacks with six well-known classifiers according to high f1-score and g-mean value in ***,amulti-layer perceptron based ensemble learning approach has been applied to improve the models’overall *** experimental results showthat the suggested model is acceptable for feature selection as well as classifying network attacks in an imbalanced dataset,with a high f1-score(0.91)and g-mean(0.99)***,it has outperformed base classifier models and voting procedures.

关键词： Ensemble methods feature selection genetic algorithm multilayer perceptron network attacks imbalanced data

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