Готові списки джерел за темами / Surface lattice modes

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Добірка наукової літератури з теми "Surface lattice modes"

Автор: Grafiati

Опубліковано: 23 вересня 2022

Оновлено: 28 січня 2023

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Статті в журналах з теми "Surface lattice modes"

Horváth, I. "Surface modes and parity violation in Schwinger model on the lattice." Nuclear Physics B - Proceedings Supplements 47, no. 1-3 (March 1996): 683–86. http://dx.doi.org/10.1016/0920-5632(96)00150-8.

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Lin, Zo-Han, Jyun-Hong Pan, and Hung-Yuan Li. "Mechanical Strength of Triply Periodic Minimal Surface Lattices Subjected to Three-Point Bending." Polymers 14, no. 14 (July 16, 2022): 2885. http://dx.doi.org/10.3390/polym14142885.

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Sandwich panel structures (SPSs) with lattice cores can considerably lower material consumption while simultaneously maintaining adequate mechanical properties. Compared with extruded lattice types, triply periodic minimal surface (TPMS) lattices have light weight but better controllable mechanical properties. In this study, the different types of TPMS lattices inside an SPS were analysed comprehensively. Each SPS comprised two face sheets and a core filled with 20×5×1 TPMS lattices. The types of TPMS lattices considered included the Schwarz primitive (SP), Scherk’s surface type 2 (S2), Schoen I-graph-wrapped package (I-WP), and Schoen face-centred cubic rhombic dodecahedron (F-RD). The finite element method was applied to determine the mechanical performance of different TPMS lattices at different relative densities inside the SPS under a three-point bending test, and the results were compared with the values calculated from analytical equations. The results showed a difference of less than 21% between the analytical and numerical results for the deformation. SP had the smallest deformation among the TPMS lattices, and F-RD can withstand the highest allowable load. Different failure modes were proposed to predict potential failure mechanisms. The results indicated that the mechanical performances of the TPMS lattices were mainly influenced by the lattice geometry and relative density.

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Song, Daohong, Cibo Lou, Liqin Tang, Zhuoyi Ye, Jingjun Xu, and Zhigang Chen. "Experiments on Linear and Nonlinear Localization of Optical Vortices in Optically Induced Photonic Lattices." International Journal of Optics 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/273857.

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We provide a brief overview on our recent experimental work on linear and nonlinear localization of singly charged vortices (SCVs) and doubly charged vortices (DCVs) in two-dimensional optically induced photonic lattices. In the nonlinear case, vortex propagation at the lattice surface as well as inside the uniform square-shaped photonic lattices is considered. It is shown that, apart from the fundamental (semi-infinite gap) discrete vortex solitons demonstrated earlier, the SCVs can self-trap into stable gap vortex solitons under the normal four-site excitation with a self-defocusing nonlinearity, while the DCVs can be stable only under an eight-site excitation inside the photonic lattices. Moreover, the SCVs can also turn into stable surface vortex solitons under the four-site excitation at the surface of a semi-infinite photonics lattice with a self-focusing nonlinearity. In the linear case, bandgap guidance of both SCVs and DCVs in photonic lattices with a tunable negative defect is investigated. It is found that the SCVs can be guided at the negative defect as linear vortex defect modes, while the DCVs tend to turn into quadrupole-like defect modes provided that the defect strength is not too strong.

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Yu, Yang, and Yilun Liu. "Lattice-Boltzmann Models Simulation of Wetting Modes on the Surface with Nanostructures." Journal of Computational and Theoretical Nanoscience 5, no. 7 (July 1, 2008): 1377–80. http://dx.doi.org/10.1166/jctn.2008.2576.

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Xie, S. J., J. S. Han, X. D. Ma, L. M. Mei, and D. L. Lin. "Lattice-Vibration Localization in Doped Polythiophene." International Journal of Modern Physics B 11, no. 04n05 (February 20, 1997): 669–81. http://dx.doi.org/10.1142/s021797929700037x.

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Vibration modes around bipolarons in polythiophene are investigated numerically by considering a chain of finite length with different boundary conditions within the framework of tight-binding model. When the periodic boundary condition is applied, we find seven localized modes, among which three are of even parity and four of odd parity. One of the even modes is due solely to the influence of sulfur heteroatom in the heterocycle and is believed to be responsible for the mode around 700 cm -1 observed in the Raman spectrum of polythiophene. The dependence of intensities of these localized modes on the chain length is also investigated. When the ends of the chain are left open, it is shown that new surface modes are created from the highest optical branch. These modes may be identified as the high-frequency modes observed in infrared active vibration and resonant Raman scattering absorption experiments.

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Golo, V. L. "Phonon modes at the reconstructed surface of a cubic lattice." Journal of Physics: Condensed Matter 2, no. 46 (November 19, 1990): 9025–40. http://dx.doi.org/10.1088/0953-8984/2/46/004.

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LEE, M. B., B. G. FREDERICK, and G. APAI. "DIPOLE ACTIVITY AND POLARISATION OF SURFACE PHONONS IN THIN IONIC FILMS." Surface Review and Letters 01, no. 04 (December 1994): 635–39. http://dx.doi.org/10.1142/s0218625x94000837.

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Surface phonon spectra in ultrathin α- Al 2 O 3 films prepared on metallic substrates show excitation of modes in the frequency range of the surface dipole forbidden ω_-branches according to the dielectric theory of EELS. We compare calculations of the z-polarisation of the FuchsKliewer modes based on lattice dynamics with dielectric theory and semi-microscopic results for a simple NaCl lattice type thin film in the limit of k→0 appropriate to the dipolar-scattering regime. The form of the primary-beam-energy-dependence of the ω_-branch in thin α- Al 2 O 3 films is similar to the lattice dynamics prediction but is of much greater intensity. While the strong k-dependence may be attributed in part to significant z-polarisation of the ω_-branch, mixing with microscopic surface modes seems likely.

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Shi, Yunjie, Wei Liu, Shidi Liu, Tianyu Yang, Yuming Dong, Degui Sun, and Guangyuan Li. "Strong Coupling between Plasmonic Surface Lattice Resonance and Photonic Microcavity Modes." Photonics 9, no. 2 (February 1, 2022): 84. http://dx.doi.org/10.3390/photonics9020084.

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We report the strong coupling between plasmonic surface lattice resonances (SLRs) and photonic Fabry-Pérot (F-P) resonances in a microcavity embedded with two-dimensional periodic array of metal-insulator-metal nanopillars. For such a plasmonic-photonic system, we show that the SLR can be strongly coupled to the F-P resonances of both the odd- and even orders, and that the splitting energy reaches as high as 153 meV in the visible regime. Taking advantage of the strong coupling, the resulted high-energy upper polariton has similar characteristics as the plasmonic SLR, but the quality factor is almost twice of that of the SLR. We expect that this work will provide a new scheme for strong coupling between plasmonic and photonic modes, and will point to a new direction to improve the quality factor of SLRs.

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Juodėnas, Mindaugas, Domantas Peckus, Tomas Tamulevičius, Yusuke Yamauchi, Sigitas Tamulevičius, and Joel Henzie. "Effect of Ag Nanocube Optomechanical Modes on Plasmonic Surface Lattice Resonances." ACS Photonics 7, no. 11 (October 20, 2020): 3130–40. http://dx.doi.org/10.1021/acsphotonics.0c01187.

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Tobing, Landobasa Y. M., Alana M. Soehartono, Aaron D. Mueller, Ken-Tye Yong, Weijun Fan, and Dao Hua Zhang. "Hybridized surface lattice modes in intercalated 3-disk plasmonic crystals for high figure-of-merit plasmonic sensing." Nanoscale 13, no. 7 (2021): 4092–102. http://dx.doi.org/10.1039/d0nr07020c.

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Більше джерел

Дисертації з теми "Surface lattice modes"

Hamdad, Sarah. "Synthèse et étude de réseaux de nanoparticules métalliques pour l'exaltation de l'électroluminescence des OLEDs via l'effet plasmonique." Thesis, Paris 13, 2021. http://www.theses.fr/2021PA131056.

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Dans ce travail de thèse, nous nous sommes intéressés à l’étude de l’amélioration des propriétés optiques et électriques des OLED en utilisant des réseaux de nanoparticules d’Ag. En particulier, nous nous sommes focalisés sur l’étude des résonances de réseau de surface (SLR) afin de comprendre l’origine des mécanismes d’interactions dans ces réseaux. Nous avons aussi étudié l’influence de ces modes sur les caractéristiques d’émission d’une couche organique d’abord en pompage optique et ensuite en pompage électrique. Pour cela, nous avons mis en place au sein du laboratoire LPL plusieurs bancs optiques et développé des calculs afin d’interpréter les résultats obtenus. Ces résultats confirment le rôle crucial des anomalies de Rayleigh dans l’interaction entre les NPs et les émetteurs organiques. En particulier, ils révèlent leur importance pour l’apparition d’une directivité de l’émission. Dans le cas des μOLED, les études réalisées montrent que la présence de réseaux de courtes périodes améliore le processus électrique d’injection des trous dans le dispositif. De plus, on montre également qu’il est possible d’exalter le rendement de la μOLED par l’insertion d’un réseau de longue périodicité. Toutefois, on souligne que l’existence de modes SLR et les effets de directivité de l’émission dans ces dispositifs nécessitent des études plus approfondies. Les résultats obtenus dans le cadre de cette thèse constituent un pas important vers une profonde compréhension des interactions entre les NPs métalliques et les émetteurs organiques et pourraient ouvrir la voie vers l’étude d’OLED superradiantes qui constituerait une étape intermédiaire pour aller vers la diode laser organique
In this thesis work, we were interested in studying the improvement of the optical and electrical properties of OLEDs using square arrays of Ag nanoparticles. In particular, we focused on the study of surface lattice resonance (SLR) modes in order to understand the interaction mechanisms between the NPs in a grating. We have also studied the influence of these modes on the emission characteristics of an organic layer first under optical pumping and then under electrical pumping. For this, we have set up within the LPL laboratory several optical experiments and developed several numerical calculations in order to interpret the obtained results. These latter confirm the crucial role of Rayleigh anomalies in the appearance of directional emission. In the case of OLEDs, the studies carried out show that the presence of short period metallic structures can help to improve the electrical injection process of holes into the organic device. Besides, we show that the insertion of a longue period grating can improve the efficiency of the OLED. However, the existence of collective SLR modes is not guaranteed in this type of configuration and the emission directivity effects require further studies. The results obtained within the framework of this thesis work constitute an important step towards a deep understanding of the interactions between the grating of metallic NPs and the organic emitters and could open the way towards the study and the realization of superriadiant OLEDs, which would constitute an intermediate step to go to the organic laser diode

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Rannou, Guillaume. "Lattice-Boltzmann method and immiscible two-phase flow." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26560.

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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Cyrus K. Aidun; Committee Member: Marc K. Smith; Committee Member: S. Mostafa Ghiaasiaan. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Donath, Stefan [Verfasser]. "Wetting Models for a Parallel High-Performance Free Surface Lattice Boltzmann Method / Stefan Donath." München : Verlag Dr. Hut, 2011. http://d-nb.info/1016531389/34.

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Bentz, Daniel N. "The effects of surface roughness and stress on lattice gas models using kinetic Monte Carlo modeling." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/289920.

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This thesis reports kinetic Monte Carlo computer simulations using a lattice gas model conducted on a variety of systems. These studies may be divided into two main categories: rod eutectics and related surface roughening, and surface morphology changes due to local stresses. The first grouping is a study of irregular rod eutectic systems. Simulations of directional solidification of rod eutectic systems were conducted using a model similar to the spin one Ising model. Growth of the rods was initiated from columns of pure A atoms embedded in a matrix of B atoms. The growth characteristics of the eutectic depend on the location of the surface roughening transition for the two phases. The surface roughening transition was determined using fluctuation dissipation theory, where the kinetic behavior of the interface is related to a characteristic time of fluctuations about an equilibrium position. These times were determined by time correlations. Results show a sharp transition in the kinetic behavior of the interface as a function of Jackson's alpha factor. This is the first time this method has been used to locate the surface roughening transition. An applied temperature gradient supplied the restoring force for the interface. The roughening behavior of binary alloys was also examined and compared to pure component systems. The second set of simulations reported here examine the effects of local stress on surface morphology. The weakening of bonds due to the dislocation stress field was studied as the origin of the formation of etch-pits at dislocations. Atoms from a diamond cubic lattice were irreversibly removed with a probability which depends on an local surface configuration as well as on the local stress developed from its physical location with respect to a dislocation in the lattice. In accordance with experimental observations, both faceted and non-faceted dislocation etch-pits have been observed. Simulations of crystal surfaces near equilibrium have reproduced direct experimental results using atomic force microscopy (AFM). The probe tip interacts with the shape and the motion of step edges, and the motion of a step is retarded in the vicinity of the tip.

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Martynec, Thomas Michael [Verfasser], Sabine [Akademischer Betreuer] Klapp, Sabine [Gutachter] Klapp, and Martin [Gutachter] Oettel. "Phase transitions and surface growth in nonequilibrium lattice models / Thomas Michael Martynec ; Gutachter: Sabine Klapp, Martin Oettel ; Betreuer: Sabine Klapp." Berlin : Technische Universität Berlin, 2021. http://d-nb.info/123917733X/34.

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Huang, Ran. "Thermodynamics and Ideal Glass Transition on the Surface of a Monatomic System Modeled as Quasi "2-Dimensional" Recursive Lattices." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1342379960.

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Vrána, Radek. "STUDY OF ENERGY ABSORPTION IN MICRO – STRUT LATTICE STRUCTURE PRODUCED BY SELECTIVE LASER MELTING." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401608.

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Předložená dizertační práce je součástí většího výzkumného projektu, který si klade za cíl využití mikro prutové konstrukce vyrobené technologií SLM jako absorbér rázové energie s přesně navrženými vlastnostmi. Hlavním cílem práce je vývoj numerického modelu deformačního chování mikro-prutové konstrukce vyrobeného technologií Selective Laser Melting (SLM) z materiálu AlSi10Mg. Aby bylo možné dosáhnout hlavního cíle dizertační práce, bylo nutné analyzovat vliv procesních parametrů technologie SLM na tvorbu vnitřních materiálových vad a drsnost povrchu při výrobě mikro-prutové konstrukce. Tyto imperfekce degradují její mechanické vlastnosti a jejich odstranění zlepší možnosti a přesnost numerické predikce. Výsledky ukazují významný vliv dvou hlavních parametrů – skenovací rychlosti laseru a výkonu laseru. Na základě těchto poznatků byly dále definovány parametry vstupní energie Ein a lineární energie Elin, které zahrnují oba zmíněné parametry a byly definovány jejich limitní hodnoty pro minimalizaci vzniklých imperfekcí. Deformační chování vyrobené mikro-prutové konstrukce bylo analyzováno na navrženém pádové zařízení, které umožňuje testování s dopadovou energií až 120 J. Deformační chování je vyhodnocováno s využitím obrazové analýzy záznamu vysoko rychlostní kamery a silového průběhu z tenzometru. Výsledky analýzy byly využity pro validaci numerického modelu v programu ANSYS Explicit, do kterého byly implementovány poznatky o reálném tvaru vyrobeného mikro-prutového materiálu ve formě eliptického modelu geometrie a informace o reálných mechanických vlastnostech ve formě vyvinutého materiálového modelu. Výsledné porovnání výsledků experimentu s predikcí numerického modelu ukazují dobrou shodu v místě maximálního zatížení Fmax (odchylka 5 %) i průběhu celé deformace vzorku. Tyto poznatky budou v budoucnu využity při návrhu absorbéru energie s definovanými mechanickými vlastnostmi.

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Humphrey, Alastair Dalziell. "Exploration of how light interacts with arrays of plasmonic, metallic nanoparticles." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/19365.

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The content of this thesis is based upon the interaction of light with metallic nanoparticles arranged in different array geometries. An incident electric field (light) can force the conduction electrons of a metallic nanoparticle to oscillate. At particular frequencies, in the optical regime for gold and silver particles, absorption and scattering of the light by the particle is enhanced, corresponding to the particle plasmon resonance. The spectral position and width of the particle plasmon resonance of an isolated single particle may be tuned by adjusting its size and shape, thus changing the surface charge distribution. Periodic arrays of particles offer additional control over the frequency and width of the resonance attributed to the re-radiating (scattering) property of plasmonic particles. By fabricating arrays with a pitch comparable to the wavelength of an isolated single particle plasmon resonance, a coherent interaction between particles may be produced, known as surface lattice resonances (SLRs). The electromagnetic coupling between in-plane particle plasmon modes for different particle array geometries is explored through experiment and theory. Firstly, SLRs in square, hexagonal and honeycomb arrays are investigated by normal-incidence extinction measurements and compared to a simple-coupled dipole model. Secondly, to verify the nature of the coupling between the scattered electric field associated with particle resonances, the incident electric field polarization-dependence of the extinction of rectangular arrays and chains is studied. Thirdly, the optical response of square arrays with a symmetric two-particle basis is investigated, particularly the retardation of the scattered electric field between particles in a pair. Fourthly, square arrays with an asymmetric two-particle basis are fabricated to explore the symmetric (dipole moments of both particles are parallel) and anti-symmetric (dipole moment of both particles anti-parallel) SLRs, excited by normal-incidence light.

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Bellouvet, Maxime. "Condensation de Bose-Einstein et simulation d’une méthode de piégeage d’atomes froids dans des potentiels sublongueur d’onde en champ proche d’une surface nanostructurée." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0265/document.

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Depuis plusieurs décennies un intérêt est né pour combiner deux systèmes quantiques pour former unsystème hybride quantique (SHQ) aux qualités qu’il serait impossible d’atteindre avec un seul des deuxsous-constituants. Parmi les systèmes quantiques, les atomes froids se distinguent par leur fort découplagede l’environnement, permettant un contrôle précis de leurs propriétés intrinsèques. En outre, les simulateursquantiques réalisés en piégeant des atomes froids dans des réseaux optiques présentent des propriétéscontrôlables (échelle d’énergie, géométrie,...) qui permettent d’étudier de nouveaux régimes intéressants enphysique de la matière condensée. Dans cette quête de phases quantiques exotiques (e.g., antiferromagnétisme),la réduction de l’entropie thermique est un défi crucial. Le prix à payer pour atteindre de si faiblestempérature et entropie est un long temps de thermalisation qui limite la réalisation expérimentale. La réductionde la période du réseau est une solution prometteuse pour augmenter la dynamique du système.Les SHQs avec des atomes froids offrent de riches perspectives mais requiert d’interfacer des systèmes quantiquesdans des états différents (solide/gaz) à des distances très proches, ce qui reste un défi expérimental.Le projet AUFRONS, dans lequel s’inscrit cette thèse, vise à refroidir un gaz d’atomes froids jusqu’aurégime de dégénérescence quantique puis de transporter et piéger ce nuage en champ proche d’une nanostructure.L’idée est d’obtenir un gaz d’atomes froids piégé dans un réseau bidimensionnel aux dimensionssublongueur d’onde, à quelques dizaines de nm de la structure. Un des objectifs est d’étudier les interactionsau sein du réseau mais également le couplage des atomes avec les modes de surface.Le travail réalisé durant cette thèse se décompose en une partie expérimentale et une partie théorique.Dans la première nous présentons le refroidissement d’atomes de 87Rb jusqu’au régime de dégénérescencequantique. La seconde partie est consacrée aux simulations théoriques d’une nouvelle méthode que nousavons implémentée pour piéger et manipuler des atomes froids à moins de 100 nm d’une nanostructure.Cette méthode, qui tire profit de la résonance plasmonique et des forces du vide (effet Casimir-Polder),permet de créer des potentiels sublongueur d’onde aux paramètres contrôlables. Nous détaillons ainsi lescalculs des forces optiques et des forces du vide que nous appliquons au cas d’un atome de 87Rb en champproche d’une nanostructure 1D
An interest for hybrid quantum systems (HSQs) has been growing up for the last decades. This object combines two quantum systems in order to take advantage of both systems’ qualities, not available withonly one. Among these quantum systems, ultracold atoms distinguish themselves by their strong decoupling from environment which enables an excellent control of their intrinsic properties. Optical lattice quantum simulators with tunable properties (energy scale, geometry,...) allows one to investigate new regimes incondensed matter physics. In this quest for exotic quantum phases (e.g., antiferromagnetism), the reduction of thermal entropy is a crucial challenge. The price to pay for such low temperature and entropy is a longthermalization time that will ultimately limit the experimental realization. Miniaturization of lattice spacingis a promising solution to speed up the dynamics. Engineering cold atom hybrids offers promising perspectives but requires us to interface quantum systems in different states of matter at very short distances, which still remains an experimental challenge.This thesis is part of the AUFRONS project, which aims at cooling down an atomic gas until the quantum degeneracy regime then transport and trap this cloud in the near field of a nanostructure. The idea is to trapcold atoms in a two-dimensional subwavelength lattice, at a few tenth of nm away from the surface. One goal is to study atom-atom interactions within the lattice but also atom-surface modes coupling.The work realized during this thesis splits into an experimental part and a theoretical part. In the firstone, we present the cooling of 87Rb atoms until the quantum degeneracy regime. The second part is dedicated to theoretical simulations of a new trapping method we have implemented to trap and manipulate cold atoms below 100 nm from structures. This method takes advantage of plasmonic resonance and vacuum forces (Casimir-Polder effect). It allows one to create subwavelength potentials with controllable parameters.We detail the calculations of optical and vacuum forces to apply them to an atom of 87Rb in the vicinity of a 1D nanostructure

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Müller, Wolf. "Oberflächenzustände in ferromagnetischen Materialien." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2004. http://dx.doi.org/10.18452/15230.

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Diese Arbeit beschäftigt sich mit theoretischen Untersuchung von Oberflächenzuständen in ferromagnetischen Halbleitern. Einleitend wird ein analytisches "tight-binding"-Modell zur Beschreibung der Oberflächenzustände. Es liefert Aussagen zur Existenz von Oberflächenzuständen, zu deren spektralen Gewicht und Position bezüglich der Energie. Das Kondogitter-Modell wird verwendet, um Korrelations- und Temperatureffekte sowie Oberflächenzustände zu beschreiben. Dies erfolgt zunächst für sc-(100)-Modellfilme im Rahmen des sf-Modells. Die temperaturabhängigen der Oberflächenzustände zeigen abhängig vom Ort in der Brillouinzone sowie den "hopping"-Parametern in der Oberfläche sowohl Stoner-artiges als auch "spin-mixing"-Verhalten. Mit wachsender Temperatur werden Lebensdauereffekte in den Spektren sichtbar. Das Kondogitter-Modell (KLM) wird auf die Mehrbandsituation zum df-Modell verallgemeinert, um eine Beschreibung der Prototypen für magnetische Halbleiter EuS und EuO zu erreichen. Durch die Kombination von LDA-Bandstrukturrechnungen mit Vielteilchenrechnungen zum Multiband-KLM ist es gelungen, die ausgeprägte Temperaturabhängigkeit des unbesetzten 5d-Leitungsbandes und das Verhalten der Oberflächenzustände in EuS- und EuO-Filmen realistisch zu beschreiben. Der exakte Grenzfall des Kondogitter-Modells, das magnetischen Polaron (T=0), ermöglicht Kombination von ab-initio-Bandstrukturrechnungen und der Vielteilchentheorie ohne das Auftreten von Doppelzählungen relevanter Wechselwirkungen. Sowohl in EuO als auch in EuS temperaturabhängige Oberflächenzustände beobachtet werden, die im Fall von EuS jedoch schwerer nachzuweisen sind, da sie im Energiebereich des Volumenbandes auftreten. Die für EuS und EuO berechneten Rotverschiebungen sowie die dickenabhängige Magnetisierung von EuS stimmen hervorragend mit experimentellen Befunden überein. Eine Vielzahl von Korrelationseffekten ist mit wachsender Temperatur in den Spektren der unbesetzten Europium-5d-Bänder zu beobachten.
This work is dedicated to the theoretical investigation of surface states in ferromagnetic semiconductors. After the introduction a exact solvable analytical model is presented. It figures out for given conditions if surface states exist, which spectral weight they have, and at which position in energy they can be found. Thereafter the Kondo-Lattice-Model (KLM) is used to describe correlation and temperature effects. The description focuses initially to the sc-(100) model films in the sf-model. The resulting temperature dependent surface states both Stoner behavior and "spin-mixing" behavior dependent on the chosen hopping parameters and the position in the two dimensional Brillouin zone. With increasing temperature (up to Tc) lifetime effects arise in the spectra. In conclusion the KLM is extended to the multi-band situation (df-Model) in order to provide a description of the prototypes of magnetic semiconductor EuS and EuO. We succeed in describing the distinct temperature dependence of the unoccupied 5d-conduction band and the behavior of the surface states in EuS and EuO films realistically by a combination of a LDA band-structure calculation and the manybody theory. The exact limiting case of the KLM (T=0) -the magnetic polaron- allows a combination of a ab-initio band-structure calculation and manybody theory without double counting of any relevant interaction. The presented theory provides numerous results. In EuO and EuS can be found temperature dependent surface states. In case of EuS it''s detection is much more complicated thus the surface state energies are located inside the energy range of the bulk band. The famous redshift in EuS and EuO and the thickness dependent film magnetization of EuS agree very well with the experimental results. A lot of correlation effects are present in the calculated unoccupied Europium 5d bands. With increasing temperature these effects become stronger.

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Книги з теми "Surface lattice modes"

Vladas, Sidoravicius, and Smirnov S. (Stanislav) 1970-, eds. Probability and statistical physics in St. Petersburg: St. Petersburg School in Probability and Statistical Physics : June 18-29, 2012 : St. Petersburg State University, St. Petersburg, Russia. Providence, Rhode Island: American Mathematical Society, 2015.

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1966-, Ellwood D. (David), and Brazilian School of Probability (14th : 2010 : Armação dos Búzios, Brazil), eds. Probability and statistical physics in two and more dimensions: Clay Mathematics Institute Summer School and XIV Brazilian School of Probability, Búzios, Brazil, July 11-August 7, 2010. Providence, R.I: American Mathematical Society, 2012.

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1936-, Ferrante John, Rodr £iguez, Agust £in M., and United States. National Aeronautics and Space Administration., eds. Modelling of surfaces. [Washington, DC]: National Aeronautics and Space Administration, 1994.

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1936-, Ferrante John, Rodrʹiguez Agustʹin M, and United States. National Aeronautics and Space Administration., eds. Modelling of surfaces. [Washington, DC]: National Aeronautics and Space Administration, 1994.

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1936-, Ferrante John, Kobistek Robert J, and United States. National Aeronautics and Space Administration., eds. Modelling of surfaces. [Washington, DC: National Aeronautics and Space Administration, 1994.

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van Houselt, Arie, and Harold J. W. Zandvliet. Self-organizing atom chains. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533046.013.9.

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This article examines the intriguing physical properties of nanowires, with particular emphasis on self-organizing atom chains. It begins with an overview of the one-dimensional free electron model and some interesting phenomena of one-dimensional electron systems. It derives an expression for the 1D density of states, which exhibits a singularity at the bottom of the band and extends the free-electron model, taking into consideration a weak periodic potential that is induced by the lattice. It also describes the electrostatic interactions between the electrons and goes on to discuss two interesting features of 1D systems: the quantization of conductance and Peierls instability. Finally, the article presents the experimental results of a nearly ideal one-dimensional system, namely self-organizing platinum atom chains on a Ge(001) surface, focusing on their formation, quantum confinement between the Pt chains and the occurrence of a Peierls transition within the chains.

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Частини книг з теми "Surface lattice modes"

Rosso, Stefano, Andrea Curtarello, Federico Basana, Luca Grigolato, Roberto Meneghello, Gianmaria Concheri, and Gianpaolo Savio. "Modeling Symmetric Minimal Surfaces by Mesh Subdivision." In Lecture Notes in Mechanical Engineering, 249–54. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70566-4_40.

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AbstractThanks to the great diffusion of additive manufacturing technologies, the interest in lattice structures is growing. Among them, minimal surfaces are characterized by zero mean curvature, allowing enhanced properties such as mechanical response and fluidynamic behavior. Recent works showed a method for geometric modeling triply periodic minimal surfaces (TPMS) based on subdivision surface. In this paper, the deviation between the subdivided TPMS and the implicit defined ones is investigated together with mechanical properties computed by numerical methods. As a result, a model of mechanical properties as a function of the TPMS thickness and relative density is proposed.

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Einstein, T. L., and R. Sathiyanarayanan. "Multisite Interactions in Lattice-Gas Models." In Nanophenomena at Surfaces, 19–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-16510-8_2.

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Landau, D. P. "Accelerated Algorithms 1: Lattice Models." In Computer Simulations of Surfaces and Interfaces, 191–206. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0173-1_10.

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Kanamori, Junjiro. "The Lattice Gas Model of Surface Ordering." In Springer Series in Solid-State Sciences, 154–66. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-82423-4_20.

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Goldammer, W., W. Ludwig, and W. Zierau. "Surface Modes and Surface Reconstruction in Diamond-Type Crystal Lattices." In Phonon Scattering in Condensed Matter V, 186–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82912-3_56.

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Xing, Xiu Qing, David Lee Butler, and Chun Yang. "A Lattice Boltzmann based Single-Phase Model: Surface Tension and Wetting." In Computational Fluid Dynamics 2006, 619–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-92779-2_97.

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Gerisch, A., A. T. Lawniczak, R. A. Budiman, H. Fukś, and H. E. Ruda. "Surface Roughening in Homoepitaxial Growth: A Lattice Gas Cellular Automaton Model." In Lecture Notes in Computer Science, 286–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-540-30479-1_30.

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Dupuis, A., A. J. Briant, C. M. Pooley, and J. M. Yeomans. "Droplet Spreading on Heterogeneous Surfaces Using a Three-Dimensional Lattice Boltzmann Model." In Lecture Notes in Computer Science, 1024–33. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-44860-8_106.

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Ashrafizaadeh, Mahmud, and Seyyed Meysam Khatoonabadi. "A Computational Model for Adjusting Surface Tension Coefficient in Pseudo-potential Lattice Boltzmann Method." In Springer Proceedings in Mathematics & Statistics, 161–70. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-99719-3_15.

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Evans, J. W., and M. Tammaro. "Chemical Diffusion, Wave Propagation, and Equistability in Lattice-Gas Models for Bistable Surface Reactions." In Springer Proceedings in Physics, 103–17. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-60095-1_14.

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Тези доповідей конференцій з теми "Surface lattice modes"

Guddala, S., R. Collison, M. Khatoniar, H. Bokhari, J. Trevino, and V. M. Menon. "Strong coupling of 2D excitons to surface lattice modes of plasmonic crystals." In CLEO: Science and Innovations. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/cleo_si.2018.sm2o.7.

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Swiecicki, Sylvia D., and J. E. Sipe. "Surface – lattice resonances in 2d arrays of spheres: multipolar couplings and normal modes." In Frontiers in Optics. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/fio.2016.jw4a.140.

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Vasko, K., F. Melli, L. Rosa, L. Vincetti, and F. Benabid. "Modal Content and Confinement Loss Evolution with Surface Roughness Profile in Hollow-Core Inhibited Coupling Tube Lattice Fibers." In CLEO: Applications and Technology. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/cleo_at.2022.jw3b.40.

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We investigate with a numerical model the confinement loss of the higher-order modes of hollow-core inhibited coupling tube lattice fibers as influenced by the power spectral distribution of transverse surface roughness in the glass tubes forming the fiber cladding.

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Melli, F., K. Vasko, L. Rosa, L. Vincetti, and F. Benabid. "Transverse Roughness Effect on Fundamental Mode Confinement Loss and Modal Content of Hollow-Core Inhibited Coupling Tube Lattice Fibers." In Specialty Optical Fibers. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/sof.2022.sotu1i.3.

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The effects of the transverse surface roughness on fiber loss and modal content in hollow-core inhibited coupling tube lattice fibers is numerically investigated. Relationship between roughness spectrum and loss of core modes is assessed.

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Panzer, Matthew, and Ken Goodson. "Thermal Interface Resistances in Nanostructures." In ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference collocated with the ASME 2007 InterPACK Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ht2007-32412.

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Nanostructured electronic and photonic devices include a high density of material interfaces, which can strongly impede heat conduction and influence performance and reliability. Thermal conduction through interfaces is a very mature field as long as the interface dimensions are large compared to the phonon wavelength. In nanostructures, however, the confinement of phonons in the directions parallel to the interface may strongly influence heat conduction. The present work investigates a model problem consisting of an abrupt junction between a harmonic 1D and 2D square lattice. The results show that energy couples to phonon modes localized near the free surface and that the energy transmission coefficient across the interface into these surface modes is less than unity even for materials with identical bulk impedances. The lattice dynamics calculations performed here provide an initial perspective on the impact of phonon confinement on the acoustic mismatch resistance and lay the groundwork for more detailed studies involving 3D molecular dynamics.

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Zhumatay, Nursultan, Bagdagul Dauyeshova, Desmond Adair, Ernesto Monaco, and Luis Rojas-Solorzano. "Lattice Boltzmann Modelling of Contact Angle and Hysteresis Under Homogeneous and Heterogeneous Dynamic Wetting Regime." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10921.

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Abstract The contact angle is a measurement of wettability of a solid surface resulting from molecular attraction or repulsion at the encounter point between a liquid-gas interface and a wall. To date, the determination of the contact angle is commonly performed experimentally with very limited numerical modelling, due to the complex nature of the intermolecular forces at the liquid-gas-solid contact point, even in static conditions. This investigation presents the numerical modelling of the contact angle in static and dynamic conditions on homogeneous and heterogeneous wetting regimes using the multiphase Shan-Chen Lattice Boltzmann Model (SC-LBM). The dynamics of the phenomenon is modelled firstly through a statically suspended droplet and secondly through a sessile droplet subject to the shear flow of air. The Wenzel and Cassie-Baxter states are well reproduced as the response to surface roughness homogeneity. Numerical results demonstrate the excellent suitability of the multiphase SC-LBM for this problem. Furthermore, contact-angle hysteresis is determined under the homogeneous wetting dynamic regime. Two different motion modes were observed during the investigation of the contact angle hysteresis.

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Dainezi, João Henrique Ribeiro, Gabriel Bellomi Schiavon, and Carlos De Marqui. "Effects of Bandgap Formation on the Aeroelastic Behavior of a Plate-Like Wing." In ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/smasis2018-8095.

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In this work the aeroelastic behavior of locally resonating periodic structures is investigated. The plate-like wing behavior will be obtained from the Love-Kirchhoff plate model with a finite number of mechanical resonators periodically distributed along its surface and using assumed-modes expansion. The unsteady aerodynamic loads are obtained from the doublet lattice model. By combining the structural and aerodynamic models, the aeroelastic behavior of the wing over a range of airflow speeds is discussed. Frequency response functions due to simultaneous base and flow excitations are calculated from the absence of flow speed to the linear flutter speed of the system without resonators. The effects of bandgap presence on the flutter boundary of the wing are also discussed.

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Ezzahri, Y., and A. Shakouri. "Transient Energy and Heat Transport in Metals." In ASME 2009 Heat Transfer Summer Conference collocated with the InterPACK09 and 3rd Energy Sustainability Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/ht2009-88280.

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A recently developed Shastry formalism for energy transport is used to analyze the temporal behavior of the energy and heat transport in metals. Comparison with Cattaneo’s equation is performed. Both models show the transition between ballistic and diffusive regimes. Furthermore, because the new model considers the discrete character of the lattice, it highlights some new phenomena such as oscillations in the energy transport at very short time scales. The energy relaxation of the conduction band electrons in metals is considered to be governed by the electron-phonon scattering, and the scattering time is taken to be averaged over the Fermi surface. Using the new formalism, one can quantify the transfer from ballistic modes to diffusive ones as energy propagates in the material and it is transformed into heat. While the diffusive contribution shows an almost exponentially decaying behavior with time, the non-diffusive part shows a damped oscillating behavior. The origin of this oscillation will be discussed as well as the effect of temperature on the dynamics of the energy modes transport.

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Whitmer, Christopher E., Atul G. Kelkar, Phuc Vu, and Frank R. Chavez. "Modeling and Control of a Morphing Airfoil." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42666.

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This paper presents aeroelastic modelling and robust control design for a morphing airfoil concept. A finite dimensional linear time invariant aeroelastic model is developed for a multi-input multi-output morphing airfoil structure. The shape of the airfoil (NACA airfoil series 2415) is controlled by actuators distributed along the top airfoil surface that produce vertical deflections of the top surface at several locations. This results in an airfoil shape change (i.e., “morphing” of the wing), which causes changes in the aerodynamic loading on the wing. The objective is to control the deformation of the airfoil in realtime so as to achieve the desirable aerodynamic forces on the wing. The structural model is developed using the finite element approach. A finite element toolbox in Matlab, namely FEMLAB, is used to obtain eigenfrequencies and mode shapes. A finite dimensional dynamic model of the structure is obtained by the assumed modes method. A static aerodynamic model is developed with a vortex lattice method and coupled with the structural dynamic model to yield a linear aeroelastic model of the morphing wing. A robust LQG design is presented for tracking the commanded lift and roll moment. Some parametric studies are also presented for the choice of different materials. Simulation results are given to demonstrate the viability of the proposed modelling and control methodology for morphing wing concept.

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Hopkins, Patrick E., Bryan J. Kaehr, Darren Dunphy, and C. Jeffrey Brinker. "Estimating Density Reduction and Phonon Localization From Optical Thermal Conductivity Measurements of Porous Silica and Aerogel Thin Films." In ASME/JSME 2011 8th Thermal Engineering Joint Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajtec2011-44137.

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In this work, we measure the thermal conductivity of mesoporous silica and aerogel thin-films using a non-destructive optical technique: time domain thermoreflectance (TDTR). Due to the rough surfaces of the optically transparent silica-based films, we evaporate an Al film on a glass cover slide and fabricate the silica structures directly on the Al film, providing a “probe-through-the-glass” configuration for TDTR measurements. This allows the thermal conductivity of mesoporous silica and aerogel thin films to be measured with traditional TDTR analyses. As the thermoreflectance response is highly dependent on the thermal effusivity of the porous structures, we estimate the density of the films by varying the heat capacity in our analysis. This density determination assumes that the solid matrix in the silica structure has the thermal conductivity as bulk SiO2, which is valid if all the lattice vibrations are localized, consistent with the minimum thermal conductivity concept. We independently determine the density of the porous silica films with nitrogen sorption measurements of thin films using a surface acoustic wave (SAW) technique. The difference between the determined from the SAW technique and that estimated by the TDTR effusivity analysis lends insight into the relative contributions of localized and propagating modes to thermal transport.

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Звіти організацій з теми "Surface lattice modes"

Aursjø, Olav, Aksel Hiorth, Alexey Khrulenko, and Oddbjørn Mathias Nødland. Polymer flooding: Simulation Upscaling Workflow. University of Stavanger, November 2021. http://dx.doi.org/10.31265/usps.203.

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There are many issues to consider when implementing polymer flooding offshore. On the practical side one must handle large volumes of polymer in a cost-efficient manner, and it is crucial that the injected polymer solutions maintain their desired rheological properties during transit from surface facilities and into the reservoir. On the other hand, to predict polymer flow in the reservoir, one must conduct simulations to find out which of the mechanisms observed at the pore and core scales are important for field behavior. This report focuses on theoretical aspects relevant for upscaling of polymer flooding. To this end, several numerical tools have been developed. In principle, the range of length scales covered by these tools is extremely wide: from the nm (10-9 m) to the mm (10-3 m) range, all the way up to the m and km range. However, practical limitations require the use of other tools as well, as described in the following paragraphs. The simulator BADChIMP is a pore-scale computational fluid dynamics (CFD) solver based on the Lattice Boltzmann method. At the pore scale, fluid flow is described by classical laws of nature. To a large extent, pore scale simulations can therefore be viewed as numerical experiments, and they have great potential to foster understanding of the detailed physics of polymer flooding. While valid across length scales, pore scale models require a high numerical resolution, and, subsequently, large computational resources. To model laboratory experiments, the NIORC has, through project 1.1.1 DOUCS, developed IORCoreSim. This simulator includes a comprehensive model for polymer rheological behavior (Lohne A. , Stavland, Åsen, Aursjø, & Hiorth, 2021). The model is valid at all continuum scales; however, the simulator implementation is not able to handle very large field cases, only smaller sector scale systems. To capture polymer behavior at the full field scale, simulators designed for that specific purpose must be used. One practical problem is therefore: How can we utilize the state-of-the-art polymer model, only found in IORCoreSim, as a tool to decrease the uncertainty in full field forecasts? To address this question, we suggest several strategies for how to combine different numerical tools. In the Methodological Approach section, we briefly discuss the more general issue of linking different scales and simulators. In the Validation section, we present two case studies demonstrating the proposed strategies and workflows.

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