Дисертації з теми "Graphite lattice"
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Burchell, T. D. "Studies of fracture in nuclear graphite." Thesis, University of Bath, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374615.
Повний текст джерелаCousins, Christopher Stanley George. "Inner elasticity and the higher-order elasticity of some diamond and graphite allotropes." Thesis, University of Exeter, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342008.
Повний текст джерелаMorrison, Craig Neil. "Lattice-modelling of nuclear graphite for improved understanding of fracture processes." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/latticemodelling-of-nuclear-graphite-for-improved-understanding-of-fracture-processes(10b302d1-88fb-466b-9030-d34b4fc33293).html.
Повний текст джерелаDutreix, Clément. "Impurity and boundary modes in the honeycomb lattice." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112217/document.
Повний текст джерелаTwo fields of research define the framework in which the present thesis can be apprehended. The first one deals with impurity and boundary modes in the hexagonal lattice. The second one concerns a spin accumulation in an out-Of-Equilibrium superconductor.Two fields of research define the framework in which the present thesis can be apprehended. The first one deals with impurity and boundary modes in the hexagonal lattice. The second one concerns a spin accumulation in an out-Of-Equilibrium superconductor.Graphene is the main motivation of the first part. From a crystallographic perspective, the carbon atoms in graphene, a graphite layer, design a triangular Bravais lattice with a diatomic pattern. This gives rise to an extra degree of freedom in the electronic band structure that crucially reveals chiral massless Dirac electrons at low-Energy. First of all, it is possible to make these chiral fermions annihilate when a uniaxial strain stretches the graphene layer. For a critical value of the strain, all the fermions become massive and nonrelativistic, which defines a Lifshitz transition. We study the impurity scattering as a function of the strain magnitude. A localised impurity yields quantum interferences in the local density of states that are known as Friedel oscillations. Because they are affected by the chiral nature of the electrons, we show that the decaying laws of these oscillations are specific to the phase the system belongs to. Thus, the impurity scattering offers the possibility to fully characterise the transition.Second, the diatomic pattern of the graphene lattice can also be considered as an invitation to the world of topological insulators and superconductors. The existence of edge states in such systems relies on the topological characterization of the band structure. Here we especially introduce a model of topological superconductor based on the honeycomb lattice with induces spin-Singlet superconductivity. When a Zeeman field breaks the time-Reversal invariance, and in the presence of Rashba spin-Orbit interactions, we give a prescription to describe the topological phases of the system and predict the emergence of Majorana modes (edge states) in strained and doped nanoribbons.The second part discusses the study of a spin accumulation in an out-Of-Equilibrium s-Wave superconductor. At the equilibrium, the superconductor is made of particles coupled by a s-Wave pairing, as well as unpaired quasiparticles. Injecting spin-Polarised electrons into the superconductor induces charge and spin imbalances. When the injection stops, it may happen that charge and spin do not relax over the same time-Scale. The first experiment that points out such a spin-Charge decoupling has recently been realised. In order to confirm this chargeless spin-Relaxation time, a new experiment has been developed [96], based on measurements in the frequency domain. Here, we address a model that fits the experimental data and thus enables the extraction of this characteristic time that is of the order of a few nanoseconds
Clough, Duncan. "Lattice Boltzmann liquid simulations on graphics hardware." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9206.
Повний текст джерелаFluid simulation is widely used in the visual effects industry. The high level of detail required to produce realistic visual effects requires significant computation. Usually, expensive computer clusters are used in order to reduce the time required. However, general purpose Graphics Processing Unit (GPU) computing has potential as a relatively inexpensive way to reduce these simulation times. In recent years, GPUs have been used to achieve enormous speedups via their massively parallel architectures. Within the field of fluid simulation, the Lattice Boltzmann Method (LBM) stands out as a candidate for GPU execution because its grid-based structure is a natural fit for GPU parallelism. This thesis describes the design and implementation of a GPU-based free-surface LBM fluid simulation. Broadly, our approach is to ensure that the steps that perform most of the work in the LBM (the stream and collide steps) make efficient use of GPU resources. We achieve this by removing complexity from the core stream and collide steps and handling interactions with obstacles and tracking of the fluid interface in separate GPU kernels. To determine the efficiency of our design, we perform separate, detailed analyses of the performance of the kernels associated with the stream and collide steps of the LBM. We demonstrate that these kernels make efficient use of GPU resources and achieve speedups of 29.6_ and 223.7_, respectively. Our analysis of the overall performance of all kernels shows that significant time is spent performing obstacle adjustment and interface movement as a result of limitations associated with GPU memory accesses. Lastly, we compare our GPU LBM implementation with a single-core CPU LBM implementation. Our results show speedups of up to 81.6_ with no significant differences in output from the simulations on both platforms. We conclude that order of magnitude speedups are possible using GPUs to perform free-surface LBM fluid simulations, and that GPUs can, therefore, significantly reduce the cost of performing high-detail fluid simulations for visual effects.
Lewis, Robert R. "Three dimensional texturing using lattices /." Full text open access at:, 1988. http://content.ohsu.edu/u?/etd,179.
Повний текст джерелаWu, Di, and 吳迪. "Theoretical studies of electronic tunneling properties in monolayer and bilayer graphene lattices." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40887960.
Повний текст джерелаWu, Di. "Theoretical studies of electronic tunneling properties in monolayer and bilayer graphene lattices." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40887960.
Повний текст джерелаRutter, Gregory Michael. "Atomic scale properties of epitaxial graphene grown on sic(0001)." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26570.
Повний текст джерелаFoulger, Iain. "Quantum walks and quantum search on graphene lattices." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27717/.
Повний текст джерелаHuder, Loïc. "Lien entre structure et propriétés électroniques des moirés de graphène étudié par microscopie à effet tunnel." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY083/document.
Повний текст джерелаRecent years have seen the emergence of two-dimensional crystalline layers, called 2D materials. Examples include the well-known graphene, insulating hexagonal boron nitride and superconducting niobium diselenide. The stacking of these 2D materials can be controlled to achieve desirable electronic properties under the form of van der Waals heterostructures. One of the simplest van der Waals heterostructures is the misaligned stacking of two graphene layers. Twisted graphene layers show a moiré pattern which can be viewed as a superperiodic potential that depends on the twist angle. The electronic properties of the twisted graphene layers are strongly linked to this moiré pattern.The subject of the present thesis is the experimental study of the link between the structural and the electronic properties of twisted graphene layers by means of low-temperature Scanning Tunneling Microscopy and Spectroscopy (STM/STS).While the effect of the twist angle has already been studied in great details, the modulation of the electronic properties by the deformation of the layers has been explored only recently. In the first part of this experimental work, a strain-driven modification of the electronic properties is probed in graphene layers with a twist angle of 1.26° grown on silicon carbide. The determined strain is found to be different in the two layers leading to a clear signature in the local electronic density of states of the moiré even at low strain magnitudes. Contrary to a strain applied in the two layers, this difference of strain between the layers (relative strain) modifies strongly the electronic band structure even at low strain magnitudes. While this relative strain is natively present, the second part of the work explores the effect of an applied strain in the layers. This is realized by approaching the STM tip to the graphene surface to trigger an interaction between the two. The resulting active modification of the density of states is shown to depend on the position on the moiré, leading to periodic instabilities at very low tip-sample distances.In the third part of the work, another type of modification of the electronic properties is studied when superconductivity was induced in the graphene layers. This is done by growing graphene on superconducting tantalum carbide in a single-step annealing. The results show the formation of a high-quality tantalum carbide layer on which graphene layers form moiré patterns. The low-temperature density of states of these moirés show evidence of a superconducting proximity effect induced by the tantalum carbide
Chu, Siu-Hang. "Making digital painting organic /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CSED%202007%20CHU.
Повний текст джерелаGurrieri, Maria Vittoria. "Twisted bilayer graphene: effective model, topological states and relevant symmetries." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23177/.
Повний текст джерелаHaughey, Kyle J. "Boundless Fluids Using the Lattice-Boltzmann Method." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/117.
Повний текст джерелаStanek, Lucas James. "Deformation of a Graphene Sheet Driven by Lattice Mismatch with a Supporting Substrate." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1493999094753307.
Повний текст джерелаSiegel, Jakob. "A CUDA optimized Lattice Boltzmann method implementation using control-structure splitting techniques." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 69 p, 2009. http://proquest.umi.com/pqdweb?did=1885754631&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Повний текст джерелаHass, Joanna R. "Structural characterization of epitaxial graphene on silicon carbide." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26654.
Повний текст джерелаCommittee Co-Chair: Conrad, Edward; Committee Co-Chair: First, Phillip; Committee Member: Carter, Brent; Committee Member: de Heer, Walter; Committee Member: Zangwill, Andrew. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Tuesday, Andrew J. "Modeling Atomic Defects in a Two-Dimensional Lennard-Jones Lattice Using Molecular Dynamics Simulations." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1334579948.
Повний текст джерелаMilicevic, Marijana. "Manipulation of Dirac Cones and Edge states in Polariton Honeycomb Lattices." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS515.
Повний текст джерелаExciton polaritons are mixed light-matter particles arising from strong coupling of quantum well excitons and cavity photons in semiconductor microcavities. They prove to be an extraordinary platform to emulate 1D and 2D Hamiltonians. This is due to the single site control when fabricating polariton lattices as well as to the possibility to directly visualize dispersion, spatial eigenfunctions and propagation of polaritons in photoluminescence experiments. By etching GaAs-based microcavity a honeycomb lattice for polaritons has been fabricated. The lowest two bands of this structure emulate for photons the π and π* bands of graphene. Remarkably, the system also permits exploring orbital degrees of freedom, inaccessible in actual graphene. In the first part of this thesis polariton emulator is used to address the physics of edge states in honeycomb lattice. New edge states, with flat and dispersive character have been discovered and visualised in orbital graphene. In the second part of the thesis we demonstrate experimentally a method to tailor the Dirac dispersion for photons. By implementing uni-axial strain in the honeycomb lattice Dirac photons that combine zero, finite and infinite effective masses are created. Presented results open new perspectives for the engineering of interfaces between various types of Dirac dispersions. Furthermore, the excitonic part of polaritons assures sensitivity to the magnetic field, creating the possibility to break the time reversal symmetry of the system and study photonic topological edge states in exotic Dirac cones. Finally, nonlinear Dirac physics can be probed in this system owing to polariton-polariton interactions
Kleeberg, Katja [Verfasser]. "Dyson-Schwinger Equations for strongly interacting fermions on the hexagonal graphene lattice / Katja Kleeberg." Gießen : Universitätsbibliothek, 2019. http://d-nb.info/1200352521/34.
Повний текст джерелаDelbosc, Nicolas. "Real-time simulation of indoor air flow using the lattice Boltzmann method on graphics processing unit." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/13546/.
Повний текст джерелаLapitski, Denis. "Development of the Quantum Lattice Boltzmann method for simulation of quantum electrodynamics with applications to graphene." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:e89cd11b-da2c-4c34-be9f-7b3d711e2e64.
Повний текст джерелаPedersen, Daniel. "Development of a Kinetic Monte Carlo Code." Thesis, Uppsala universitet, Materialteori, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-202711.
Повний текст джерелаRavaioli, Giacomo. "Simulazione di fluidi in Computer Graphics." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10296/.
Повний текст джерелаVinogradov, Nikolay. "Controlling Electronic and Geometrical Structure of Honeycomb-Lattice Materials Supported on Metal Substrates : Graphene and Hexagonal Boron Nitride." Doctoral thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-194089.
Повний текст джерелаSzulakowska, Ludmila. "Electron-electron Interactions and Optical Properties of Two-dimensional Nanocrystals." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40983.
Повний текст джерелаTonnoir, Charlène. "Spectroscopie tunnel de graphène épitaxié sur du rhénium supraconducteur." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENY043/document.
Повний текст джерелаObtaining a transparent interface between graphene and a superconductor has proved to be very challenging and yet essential to induce superconducting correlations in graphene via the so-called proximity effect. This thesis presents a scanning tunneling spectroscopy (STS) study at very low temperature (50 mK) of a novel system achieving such a good electronic contact by the growth of epitaxial graphene on superconducting rhenium. The fabrication and selection of high-crystallographic quality rhenium thin films are briefly explained, followed by the CVD growth process of graphene on various metal substrates and in particular rhenium. STM topographic images reveal a moiré pattern due to the lattice mismatch between graphene and rhenium. We identify this system to a graphene monolayer in strong interaction with the underlying substrate, as corroborated by DFT calculations. STS analyses in the hundreds-meV energy range show a spatial modulation of the density of states (DOS) at the moiré scale, indicating different coupling strengths between ‘hills' and ‘valleys' regions. The bulk superconducting properties are probed by transport measurements, from which we extract the transition temperature Tc~2K and a superconducting coherence length ξ=18nm. The superconducting gap is extracted from the DOS at 50 mK (Δ=330µeV) and found homogeneous at the moiré scale. The superconducting mixed state is studied under magnetic field and an Abrikosov vortex-lattice is uncovered. Finally, a study on various surface morphologies exhibits an anomalous lateral superconducting proximity effect in contradiction with the existing models
Bach, Matthias [Verfasser], Volker [Akademischer Betreuer] Lindenstruth, Owe [Akademischer Betreuer] Phlipsen, and Tilo [Akademischer Betreuer] Wettig. "Energy- and cost-efficient Lattice-QCD computations using graphics processing units / Matthias Bach. Gutachter: Volker Lindenstruth ; Owe Phlipsen ; Tilo Wettig. Betreuer: Volker Lindenstruth." Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2015. http://d-nb.info/1067918248/34.
Повний текст джерелаSjölund, Johannes. "Real-time Thermal Flow Predictions for Data Centers : Using the Lattice Boltzmann Method on Graphics Processing Units for Predicting Thermal Flow in Data Centers." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70530.
Повний текст джерелаFielding, Andrew L. "Final state effects in neutron Compton scattering measurements." Thesis, University of Portsmouth, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310441.
Повний текст джерелаJudice, Sicilia Ferreira Ponce Pasini. "Modelagem e simulação de fluidos via técnicas de sketching, modelos de difusão-reação e método de lattice Boltzmann." Laboratório Nacional de Computação Científica, 2017. https://tede.lncc.br/handle/tede/241.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
This work presents a methodology involving two-dimensional fluids initialization through sketching techniques (free draw on tablets, for example) along with diffusion-reaction equations and fluid simulation using Lattice Boltzmann Method (LBM). In the initial stage, the framework converts the drawings made by the users into streamlines. From these lines it is generated a partial velocity field, which is widespread throughout the fluid domain through diffusion-reaction techniques. The velocity field obtained at the end of the process is used to initialize the fluid simulation via the LBM method. We tested two diffusion-reaction techniques, one based on differential equations (Gradient Vector Flow) and another in LBM models. We discussed aspects of vector fields topology and fluid dynamics involved in the sketching conversion into streamlines, as well as the preservation of singularities by the diffusion-reaction methods analyzed. The aim of our application is in the areas of visual effects and computer graphics. In this sense, we presented visual results involving the theoretical concepts which demonstrate the potential of the methodology presented for computational fluid animation .
Neste trabalho apresentamos uma metodologia envolvendo inicialização de fluidos bidimensionais usando técnicas de sketching (desenho livre em tablets, por exemplo) juntamente com equações do tipo difusão-reação e simulação do fluido usando método Lattice Boltzmann (LBM). Na etapa inicial, o framework converte os desenhos feitos pelo usuário em linhas de corrente. A partir destas linhas é gerado um campo de velocidades parcial, que é difundido por todo o domı́nio do fluido via técnicas de difusão-reação. O campo de velocidades obtido no final deste processo é usado para inicializar a simulação do fluido via método LBM. Foram testadas duas técnicas de difusão-reação, uma baseada em equações diferenciais (Gradient Vector Flow ) e outra em modelos do tipo LBM. São discutidos aspectos de topologia de campos vetoriais e dinâmica de fluidos envolvidos na conversão do sketching em linhas de corrente, bem como na preservação de singularidades pelos métodos de difusão-reação analisados. Nosso foco de aplicação está nas áreas de efeitos visuais e computação gráfica. Neste sentido, são apresentados resultados visuais envolvendo os conceitos teóricos os quais demonstram a potencialidade da metodologia apresentada para animação computacional de fluidos.
Obrecht, Christian. "High performance lattice Boltzmann solvers on massively parallel architectures with applications to building aeraulics." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00776986.
Повний текст джерелаHagan, Aaron M. "PARALLEL 3D IMAGE SEGMENTATION BY GPU-AMENABLE LEVEL SET SOLUTION." Kent State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=kent1242262556.
Повний текст джерелаMorvan, Alexis. "Honeycomb lattices of superconducting microwave resonators : Observation of topological Semenoff edge states." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS037/document.
Повний текст джерелаThis thesis describes the realization and study of honeycomb lattices of superconducting resonators. This work is a first step towards the simulation of condensed matter systems with superconducting circuits. Our lattices are micro-fabricated and typically contains a few hundred sites. In order to observe the eigen-modes that appear between 4 and 8 GHz, we have developed a mode imaging technique based on the local dissipation introduced by a laser spot that we can move across the lattice. We have been able to measure the band structure and to characterize the edge states of our lattices. In particular, we observe localized states that appear at the interface between two Semenoff insulators with opposite masses. These states, called Semenoff states, have a topological origin. Our observations are in good agreement with ab initio electromagnetic simulations
Carrega, Matteo. "Coulomb drag and Dirac plasmons in novel 2D electron systems." Doctoral thesis, Scuola Normale Superiore, 2014. http://hdl.handle.net/11384/85870.
Повний текст джерелаSchumacher, Stefan [Verfasser], Thomas [Akademischer Betreuer] Michely, Tim O. [Akademischer Betreuer] Wehling, and Heiko [Akademischer Betreuer] Wende. "Structure, Magnetism, and Binding of Novel Two-Dimensional Materials: Europium-Intercalated Graphene, Cluster Lattices, and Polar Oxide Bilayers / Stefan Schumacher. Gutachter: Thomas Michely ; Tim O. Wehling ; Heiko Wende." Köln : Universitäts- und Stadtbibliothek Köln, 2014. http://d-nb.info/1058946226/34.
Повний текст джерелаOliveira, Fabíola Martins Campos de 1988. "GPU implementation of a fluid dynamics interactive simulator based on the Lattice Boltzmann method = Implementação em GPU de um simulador interativo de fluidodinâmica com o método das Redes de Boltzmann." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265825.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Recentes avanços na tecnologia de processadores multinúcleos e vários-núcleos popularizaram a computação paralela, acelerando a execução de programas e possibilitando a simulação de domínios maiores. Dentre os problemas complexos que requerem alta velocidade de processamento, os problemas de fluidodinâmica computacional se destacam, já que suas simulações tendem a ter um alto custo computacional e exigem grandes domínios de simulação. O método baseado nas Redes de Boltzmann é um método de fluidodinâmica computacional apropriado para o uso de paralelismo que vem ganhando destaque na comunidade científica. Embora haja trabalhos que explorem o paralelismo em GPU nesse método, um simulador eficiente na execução e visualização interativa ainda não foi explorado adequadamente. Assim, a proposta deste trabalho é implementar em GPU um simulador interativo de fluidodinâmica com o método das Redes de Boltzmann. Inicialmente, o simulador foi desenvolvido em linguagem C e foi paralelizado em CPU usando MPI. Em seguida, foi paralelizado em GPU usando CUDA e convertido para linguagem orientada a objetos em C++. Depois, a visualização interativa foi acrescentada utilizando técnicas como interoperabilidade entre CUDA e OpenGL, texturização 3D, fluxo programável da GPU, além de funções de interação com o usuário. O simulador foi validado para casos 2D e 3D em fluxos monocomponentes monofásicos. Além disso, para demonstrar o ganho de desempenho em velocidade de processamento de problemas paralelizados em relação a execuções sequenciais, um conjunto de testes com tamanhos crescentes de domínio foi desenvolvido. O resultado dessa comparação indicou que o simulador implementado em GPU com visualização interativa teve desempenho 71.3 vezes maior em relação à versão sequencial em CPU sem visualização interativa. Dessa forma, a abordagem de paralelização em GPU com visualização interativa mostrou-se muito adequada à execução de simulações fluidodinâmicas, sendo uma ferramenta útil no estudo de escoamentos fluídicos, capaz de executar inúmeros cálculos e lidar com a grande quantidade de memória exigida por simulações fluídicas
Abstract: Recent advances on multicore and many-core processor technology have popularized the parallel computing, accelerating program execution and enabling the simulation of larger domains. Within the complex problems that require a high processing speed, the computational fluid dynamics problems stand out, since their simulations tend to have high computational cost and demand large simulation domains. The method based on the Lattice Boltzmann is an appropriate computational fluid dynamics algorithm to explore parallelism that has been noteworthy in scientific community. Although there are several works that approach GPU parallelism in this method, an efficient simulator implementation and interactive visualization have not been explored adequately. Thus, the purpose of this work is to implement in GPU an interactive fluid dynamics simulator based on the Lattice Boltzmann method. First, the simulator was developed in C language and was parallelized in CPU using MPI. Next, it was parallelized in GPU using CUDA and converted into C++ object-oriented language. Then, the interactive visualization was added using techniques such as CUDA-OpenGL interoperability, 3D texturing, GPU programmable pipeline, and interaction features. The simulator was validated for 2D and 3D cases in single component, single phase flows. Besides that, to show the performance gain in processing velocity of parallelized problems in relation to sequential executions, a test set with increasing domain sizes was developed. This comparison result indicated the GPU-implemented interactive simulator was 71.3 times faster in relation to sequential CPU version without interactive visualization. Thereby, the GPU parallelization approach with interactive visualization showed to be very adequate to fluid dynamics simulations, being a useful tool in fluid flow study, capable of simulating numerous calculations and dealing with the large amount of memory required in fluidic simulations
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestra em Engenharia Mecânica
Pogorelcnik, Romain. "Decomposition by complete minimum separators and applications." Thesis, Clermont-Ferrand 2, 2012. http://www.theses.fr/2012CLF22301/document.
Повний текст джерелаWe worked on clique minimal separator decomposition. In order to compute this decomposition on a graph G we need to compute the minimal separators of its triangulation H. In this context, the first efforts were on finding a clique minimal separators in a chordal graph. We defined a structure called atom tree inspired from the clique tree to compute and represent the final products of the decomposition, called atoms. The purpose of this thesis was to apply this technique on biological data. While we were manipulating this data using Galois lattices, we noticed that the clique minimal separator decomposition allows a divide and conquer approach on Galois lattices. One biological application of this thesis was the detection of fused genes which are important evolutionary events. Using algorithms we produced in the course of along our work we implemented a program called MosaicFinder that allows an efficient detection of this fusion event and their pooling. Another biological application was the extraction of genes of interest using expression level data. The atom tree structure allowed us to have a good visualization of the data and to be able to compute large datasets
Gastineau, Nicolas. "Partitionnement, recouvrement et colorabilité dans les graphes." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS014/document.
Повний текст джерелаOur research are about graph coloring with distance constraints (packing coloring) or neighborhood constraints (Grundy coloring). Let S={si| i in N*} be a non decreasing sequence of integers. An S-packing coloring is a proper coloring such that every set of color i is an si-packing (a set of vertices at pairwise distance greater than si). A graph G is (s1,... ,sk)-colorable if there exists a packing coloring of G with colors 1,... ,k. A Grundy coloring is a proper vertex coloring such that for every vertex of color i, u is adjacent to a vertex of color j, for each ji. These results allow us to determine S-packing coloring of these lattices for several sequences of integers. We examine a class of graph that has never been studied for S-packing coloring: the subcubic graphs. We determine that every subcubic graph is (1,2,2,2,2,2,2)-colorable and (1,1,2,2,3)-colorable. Few results are proven about some subclasses. Finally, we study the Grundy number of regular graphs. We determine a characterization of the cubic graphs with Grundy number 4. Moreover, we prove that every r-regular graph without induced square has Grundy number r+1, for r<5
Dao, Ngoc Bich. "Réduction de dimension de sac de mots visuels grâce à l’analyse formelle de concepts." Thesis, La Rochelle, 2017. http://www.theses.fr/2017LAROS010/document.
Повний текст джерелаIn several scientific fields such as statistics, computer vision and machine learning, redundant and/or irrelevant information reduction in the data description (dimension reduction) is an important step. This process contains two different categories : feature extraction and feature selection, of which feature selection in unsupervised learning is hitherto an open question. In this manuscript, we discussed about feature selection on image datasets using the Formal Concept Analysis (FCA), with focus on lattice structure and lattice theory. The images in a dataset were described as a set of visual words by the bag of visual words model. Two algorithms were proposed in this thesis to select relevant features and they can be used in both unsupervised learning and supervised learning. The first algorithm was the RedAttSansPerte, which based on lattice structure and lattice theory, to ensure its ability to remove redundant features using the precedence graph. The formal definition of precedence graph was given in this thesis. We also demonstrated their properties and the relationship between this graph and the AC-poset. Results from experiments indicated that the RedAttsSansPerte algorithm reduced the size of feature set while maintaining their performance against the evaluation by classification. Secondly, the RedAttsFloue algorithm, an extension of the RedAttsSansPerte algorithm, was also proposed. This extension used the fuzzy precedence graph. The formal definition and the properties of this graph were demonstrated in this manuscript. The RedAttsFloue algorithm removed redundant and irrelevant features while retaining relevant information according to the flexibility threshold of the fuzzy precedence graph. The quality of relevant information was evaluated by the classification. The RedAttsFloue algorithm is suggested to be more robust than the RedAttsSansPerte algorithm in terms of reduction
Mohanta, Zinia. "Engineering Graphene Oxide Surface Chemistry and Investigating Its Effect on The Physicochemical and Biological Properties." Thesis, 2021. https://etd.iisc.ac.in/handle/2005/4902.
Повний текст джерелаSio, Kuan-Un, та 蕭君源. "Multi-Functional Light Emitter Based on Band-Edge Modes Near Γ-Point in Graphite Lattice Photonic Crystal". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/60622431264128165064.
Повний текст джерела國立交通大學
光電工程學系
99
Photonic band-edge mode utilizes the flat photonic band near lattice symmetry point, enhances light-gain interaction and achieves lasing operation due to the slow light effect. Among those symmetry points, band-edge mode near Γ-point with almost zero in-plane wave vector component favor for directional surface emission. In this thesis, we successfully demonstrated a multi-functional light emitter based on band-edge modes near Γ-point of graphite lattice in two-dimensional photonic crystal slab. Compare to typical triangular or square lattice, graphite lattice with reduced air hole density leads to larger gain volume and better heat dissipation. At first, the photonic band diagram and related band-edge mode profiles of graphite lattice are simulated and characterized by 3D plane-wave-expansion method. And real devices with different lattice constant are fabricated by series of semiconductor fabrication process. By measuring the optical properties of band-edge modes near different Γ-point, including the monopole (Γ2), dipole (Γ4,5), and quadrupole (Γ6,7) modes. We observed single mode lasing action from monopole and quadrupole modes at room temperature respectively. The monopole mode with high side-mode suppression-ratio of 30 dB shows its ability for optical micro-laser application. And quadrupole mode exhibit high index sensitivity of 375 nm/RIU by the measuring lasing spectra with different index match liquid, show its potential in refractive index sensor for biochemical detection. Besides these two lasing modes, over five-fold photoluminescence enhancement with broad band-width of 100 nm from the dipole mode is also observed, which is promising in realize high brightness light-emitting-diodes.
Sanchez-Cortezon, Emilio [Verfasser]. "The role of lattice defects in the catalytic oxidation of methanol over graphite catalysts / vorgelegt von Emilio Sanchez-Cortezon." 2003. http://d-nb.info/967765366/34.
Повний текст джерелаClough, Duncan. "Lattice Boltzmann Liquid Simulations on Graphics Hardware." Thesis, 2013. http://pubs.cs.uct.ac.za/archive/00000951/.
Повний текст джерелаDammertz, Sabrina [Verfasser]. "Rank-1 lattices in computer graphics / Sabrina Dammertz." 2009. http://d-nb.info/997297174/34.
Повний текст джерелаLin, Bo-sing, and 林柏興. "Graphene Oxide Cathode of Field Emission Emitter with Square Lattice Island Array." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/58838607041257048340.
Повний текст джерела國立中山大學
電機工程學系研究所
104
Graphene has attracted the attention of most scholars for its unique properties, such as high electron mobility, high thermal conductivity, low resistivity and other physical characteristics which was discovered by A.K Geim since 2004. Graphene can be widely applied such as transistor, sensor, field emission device and other research. This thesis is divided into three parts: First of all, the graphene oxide is made by electrochemical exfoliation. Secondly, to make graphene oxide as square lattice island array is using screen printing method. Lastly, the field emission of graphene oxide patterns is measured in different diameter. Graphene oxide is made from highly oriented pyrolytic graphite by electrochemical exfoliation. Before the screen printing process, graphene oxide is analyzed with Raman spectroscopy, XRD, and XPS, which makes sure the quality and purity. In the research, use the AutoCAD software to design the mask in different diameter for the screen printing. In OM and SEM images, the screen printed graphene oxide with the island patterns constructing perpendicular edge shows the best aspect ratio, and then all of them has become square lattice array emitter. When the screen-printed graphene oxide in different diameter is measured, it’s found that the best performance is the diameter of 150μm. The emission behavior of the diameter in 150μm is 1.65 V⁄μm with the maximum emission current of 20.8μA and the field enhancement factor of 15060. It''s worth noting that the diameter in 100μm shows the worst emission behavior because of the screening effect. The luminance measurement of the best condition coating the phosphor shows the maximum amount of green light with the wavelength at 562 nm and the lumens of 5.04 when the emission current is up to 20.8μA.
Carlstrand, Harald, Björn Rosén, and Helena Andersson. "Elastic properties of Heusler alloys by ab initio theory and lattice dynamics of graphene." Thesis, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226508.
Повний текст джерелаKitt, Alexander. "Manipulating graphene's lattice to create pseudovector potentials, discover anomalous friction, and measure strain dependent thermal conductivity." Thesis, 2014. https://hdl.handle.net/2144/15101.
Повний текст джерелаWang, Sheng. "Artificial Graphene in Nano-patterned GaAs Quantum Wells and Graphene Growth by Molecular Beam Epitaxy." Thesis, 2016. https://doi.org/10.7916/D8DF6RGW.
Повний текст джерела"Quantum Monte Carlo study of frustrated systems." Thesis, 2010. http://library.cuhk.edu.hk/record=b6074995.
Повний текст джерелаIn the chapter 4, we addresses the issue of the ferromagnetism in graphene-based samples. To study magnetic correlations in graphene, we systematically carry out quantum Monte Carlo simulations of the Hubbard model on a honeycomb lattice. In the filling region below the Van Hove singularity, the system shows a short-range ferromagnetic correlation, which is slightly strengthened by the on-site Coulomb interaction and markedly by the next-nearest-neighbor hopping integral. The ferromagnetic properties depend on the electron filling strongly, which may be manipulated by the electric gate. Due to its resultant high controllability of ferromagnetism, graphene-based samples may facilitate the new development of many applications.
In the chapter 5, we examined theoretically the magnetism of impurity adatoms in graphene by quantum Monte Carlo simulation technique based on Hirsch-Fye algorithm. When tuning the Fermi energy of graphene by gate voltage with available experiments, the values of occupancy and local moment for impurity can be changed. Furthermore, with medium and large hybridizations between impurity and graphene atoms, the local moment can be switched on and off by Kondo effects. We also use maximum entropy method to study the spectral density from Green's function for impurity, and we find very unconventional behaviors which are absolutely different from the cases in the normal metal. These signatures of spectral density enlarge the possibility for controlling the impurity magnetism by gate voltage.
In this research thesis, we mainly study three strongly correlated systems: Hubbard model in bilayer triangular lattice which corresponds to the real material of NaxCoO2 · yH 2O, strong-interaction electrons in graphene system and Anderson impurity in graphene. Our numerical method is determinant quantum Monte Carlo method which will be introduced in the chapter 2.
Hu, Feiming = 阻錯系統的量子門特卡洛研究 / 胡飛鳴.
Adviser: Lin Hai-Qing.
Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2010.
Includes bibliographical references (leaves 107-126).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
Hu, Feiming = Zu cuo xi tong de liang zi Mente Kaluo yan jiu / Hu Feiming.