Дисертації з теми "Anisotropic liquids"
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Loussert, Charles. "Mise en forme topologique : lumière et cristaux liquides." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0325/document.
Повний текст джерелаThe enclosed work deals with the study of the topological shaping of light and matter and will bedivided into two categories of research. The first focuses on the topological shaping of light from liquid-crystal based spin-orbit interfaces. In particular, we show in this manuscript, that different systems based on the use of natural topological defects behave as highly efficient natural optical spin-orbit encoders, for distinct topological charges, at the micron scale and with spatial control.The operating wave length and operation mode of such interfaces can be tuned in real-time using low voltage electric fields. This breakthrough opens the path to the ultra-broadband control of the light’sorbital state. The second category concerns the topological shaping of a cholesteric liquid crystal film in context of mass data storage. We show the potential to generate metastable topological mi-crostructures in a controlled and reconfigurable way, both in time and space and with a low energy cost. We also demonstrated a new, unique type of rewritable memory, controlled by the«spin»ofthe laser-generated incident photon
Simmonds, Paul Stuart John. "Theoretical studies of anisotropic fluids." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314781.
Повний текст джерелаNicholson, Timothy Michael. "Anisotropic structure in liquid crystalline polymers." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293821.
Повний текст джерелаLeite, Rubim Rafael. "Graphene oxide sheets confined within anisotropic fluid matrices." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0209/document.
Повний текст джерелаSince the discovery of graphene oxide (GO), the most accessible of the precursors of graphene, this material has been widely studied for applications in science and technology. The motivation of this work is to study with a fundamental perspective the coupling between amphiphilic bilayers, which can be seen as an anisotropic matrix formed of two-dimensional objects, and another two-dimensional object, namely the graphene oxide sheet when they are dispersed in a common solvent. The competition between the intrinsic elasticities of the bilayers and GO sheets, as well as between direct bilayer-bilayer, bilayer-GO and GO-GO interactions allows us to envisage a rich polymorphism, depending on the composition of the system. Following the development of a dedicated procedure for controlling in an extended range of GO content the binary GO-water system, the confined domain of aqueous GO dispersions was first investigated, and the ternary phase diagram then constructed. The obtained systems have been characterised, using techniques such as optical microscopy, light and x-ray scattering. Elastic and thermodynamic properties have been described by applying, and adapting to the scope of this study, models for two-component lamellar stacks
Desde sua descoberta, o grafeno oxidado (GO), o mais acessível dos precursores do grafeno,tem sido amplamente utilizado para aplicações na ciéncia e tecnologia. A motivação destetrabalho é de estudar, de um ponto de vista fundamental, o acoplamento entre bicamadas anfifílicas auto-organizadas (que podem ser vistas como uma matriz anisotrópica formada por objetos bidimensionais) e um objeto ele mesmo bidimensional, neste caso a folha de óxido de grafeno, quando estão dispersados em um solvente comum.A competição entre as elasticidades intrínsecas das bicamas e das folhas de GO, assimcomo as interaçãoes diretas bicamada-bicamada, bicamada-GO e GO-GO, permitem esperar um rico polimorfismo em função da composição do sistema. Seguindo o desenvolvimento de um procedimento destinado ao controle, em um intervalo extendido da quantidade de GO, o sistema binário GO-água, o domínio confinado de dispersões aquosas de GO foi explorado e, em seguida, o diagrama de fases ternário contruído.Os sistemas obtidos foram caracterizados por t_ecnicas como microscopia ótica, espalhamento dinâmico de luz e espalhamento de raios-x à baixos ângulos. As propriedadeselásticas e termodinâmicas foram descritas pela aplicação de modelos inicialmente concebidos para fases lamelares à dois constituintes e adaptados ao escopo deste estudo
Mondiot, Frédéric. "Comportement de particules colloïdales dans des solvants nématiques : influence de la forme et de la taille." Phd thesis, Bordeaux 1, 2011. http://tel.archives-ouvertes.fr/tel-00657747.
Повний текст джерелаPetit, Mohamed. "Etudes des propriétés électro-optiques, diélectriques et structurales d'un cristal liquide ferroélectrique stabilisé par un réseau polymère." Littoral, 2007. http://www.theses.fr/2007DUNK0186.
Повний текст джерелаWe report in this work the effect of an anisotropic polymer network formed from an achiral photo-reactive monomer in a short pitch chiral SmC* phase, on the coupling of liquid crystal molecules to applied electric field. The formation of the polymer network is based on a photo-induced self-structuring process and alignment of photo-reactive mesogenic monomers, initially dispersed in a SmC* liquid crystal matrix. This allows to a gel composite material. The self-structured network plays in turn a crucial role on the behaviour of the liquid crystal under external electric field. Experimental data, obtained from electro-optic and dielectric measurements, showed that the anisotropic polymer network stabilizes not only the helical structure of the ferroelectric SmC* phase, but also the orthogonal order of the paraelectric SmA phase. We have demonstrated this effect to be related to network morphology. AFM experiments have shown a fibrillar and anisotropic structure of the network. The experimental results were discussed in the framework of a simple phenomenological model, extended from the Landau model, including the bulk free energy arising from the liquid crystal/polymer anisotropic interaction, and the elastic free energy resulting from the anchoring of liquid crystal molecules at the polymer boundaries. The coupling parameter characterizing the liquid crystal/polymer interaction was evaluated as a function of polymer network density. This interaction can be qualified as “strong”, and results on the increase of the effective elasticity of the gels
Geronimo, Luiz Alceu. "Medidas da anisotropia dielétrica de cristais líquidos nemáticos." Florianópolis, SC, 1985. https://repositorio.ufsc.br/handle/123456789/106255.
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Cruceanu, Florentin I. "AC-calorimetry and dielectric spectroscopy on anisotropic liquid crystal and aerosil dispersions." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-040908-143149/.
Повний текст джерелаKeywords: phase transitions; quenched random disorder; liquid crystals; dielectric spectroscopy; calorimetry. Includes bibliographical references (leaves 78-83).
Forrest, Richard. "Preparation of anisotropic microparticles and their behaviour at liquid interfaces." Thesis, University of Hull, 2012. http://hydra.hull.ac.uk/resources/hull:8606.
Повний текст джерелаTimperley, Christine Ann. "Reflectance anisotropy spectroscopy of thermotropic liquid crystals." Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428215.
Повний текст джерелаFoster, Kathryn Ellen. "Thin aligned organic polymer films for liquid crystal devices." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4895/.
Повний текст джерелаNourry, Johnny Jacques. "Etude de microcomposites de type polymère cristal liquide chiral." Nice, 1998. http://www.theses.fr/1998NICE5149.
Повний текст джерелаD'hulst, René. "Modèles unidimensionnels pour cristaux liquides en colonnes." Sherbrooke : Université de Sherbrooke, 1997.
Знайти повний текст джерелаCos, Córcoles Joaquín. "Design and modelling of photonic crystals with anisotropic components." Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/8479.
Повний текст джерелаFabry-Pèrot. Estos dispositivos permiten sintonizar 2 resonancias en sus frecuencias y amplitudes de transmisión. En cuanto a los cristales fotónicos 2D, se ha analizado filtros y guías de onda sintonizables, proponiendo en ambos casos aplicaciones como interruptores ópticos. Por último, se ha desarrollado una aproximación para el análisis de cristales fotónicos 3D. Mediante dicha aproximación se ha explicado la presencia de máximos en reflexión en altas frecuencias así como se han analizado 3 muestras experimentales.
The present Communications Age requires more and more efficient devices in terms of speed, consumption and size for the treatment of information. Nanoscale photonic crystal devices and anisotropic materials is expected to provide a possibility to create electro-optical devices with required characteristics such us tunability. In this work we have analyzed and designed several tunable one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) devices based on silicon photonic crystals and liquid crystal. In the case of 1D photonic crystals, two optical equalizers based on Fabry-Perot interferometers have been proposed. These devices allow tuning 2 resonances in frequencies and transmission amplitudes. As for 2D photonic crystals, tunable filters and waveguides have been analyzed, offering both applications as optical switches. Finally, we have developed an approach for the analysis of 3D photonic crystals. The presence of reflection peaks in high frequencies has been explained by this approach and 3 experimental samples were analyzed.
Silva, Márcio Higino da. "Efeito da adição de sais eletrolíticos monovalentes na estrutura, forma e ordem orientacional dos agregados micelares da mistura binária amônio pentadecafluorooctanoato e água." Florianópolis, SC, 2008. http://repositorio.ufsc.br/xmlui/handle/123456789/91347.
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O principal objetivo das pesquisas realizadas e apresentadas neste trabalho esta concentrada nos efeitos da adicao de sais eletroliticos monovalentes fortes, como o cloreto de amonio (NH4Cl) e o cloreto de potassio (KCl), na formação de novas estruturas com propriedades liquido-cristalinas ou mudanças drasticas nas estruturas micelares pré-existentes, nas fases micelares isotropica, nematica e lamelar presentes no sistema binario contendo o surfactante amonio entadeca°uorooctanoato e agua (APFO / H2O). Inves-tigamos tambem, a in°u^encia que os sais NH4Cl e KCl produziram na forma e no tamanho dos agregados micelares, bem como sua dependencia com a temperatura. Diversas tecnicas experimentais, como microscopia optica, refratometria de ABBE, tramitancia de luz, difraçao por raios X e etc, foram usadas e dos resultados destas medidas, suas temperaturas de transicoes de fases foram determinadas e uma nova estrutura, formada espontaneamente na solucao e denominada "vesiculas", foi identicada, isto e, estas vesiculas aparecem simplesmente pelo efeito do sal adicionado. Estudos teoricos usando campo medio (Maier-Saupe) em combinaçao, com resultados experimentais foram realizados e o comportamento do paramentro de ordem orientacional micelar com a temperatura, foram obtidas para varias amostras. The main aim of the research performed and presented in this work is concentrated in the e®ects of the addition of strongs monovalents electrolytic salts, as the ammonium chloride (NH4Cl) and the potassium chloride (KCl), in the formation of new structures with liquid-crystallines properties or drastic changes in pre-existing micellar structures in the isotropic, nematic and lamellar phases present in the binary system containing the surfactant pentadeca°uorooctanoate and water (APFO / H2O). We also investigated the in°uence that the salts (NH4Cl and KCl) had on the size and shape of the micellar aggregates as well as their dependency on temperature. Several experimental techniques such as polarizing optical microscopy, direct bulk solution observation, Abbe refractometry, laser light transmission and small angle X ray di®raction were used and from results of these measurements, phase transitions temperatures were determined and, a new structure, formed spontaneously in the solution and named "vesicles", was identi¯ed, i.e., these vesicles appear in the solution simply by the e®ect of the added salt. Theoretical studies using mean ¯eld approximation (Maier-Saupe) in combination with experimentals data were performed and the behavior of the micellar orientational order parameter on temperature, for several samples, obtained.
Shafran, Matthew S. "Responsive liquid crystal polymer rods." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5598.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains viii, 71 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 63-67).
Syvitski, Raymond Thomas. "Probing anisotropic intermolecular forces in nematic liquid crystals using NMR and computer simulations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/NQ48727.pdf.
Повний текст джерелаNewton, Bethany Jade. "Using external fields to control the behaviour of anisotropic particles at liquid interfaces." Thesis, University of Hull, 2016. http://hydra.hull.ac.uk/resources/hull:15426.
Повний текст джерелаDaffé, Niéli. "Anisotropies and Magnetic Couplings of Texturable Ferrofluids." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066640/document.
Повний текст джерелаFerrofluids are colloidal suspensions of magnetic nanoparticles dispersed in a carrier liquid. The intimate interaction between the magnetic nanoparticles and the liquid provides a unique system, from both fundamental and industrial application point of views, whose flow and properties can be precisely controlled using an external magnetic field. Magnetic nanoparticles of spinel ferrites MFe2O4 (M = Fe2+, Co2+, Mn2+…) are of particular scientific interest and have been extensively studied for their electrical and magnetic properties. Spinel ferrites find potential applications, notably in storage devices, for computers, or hyperthermia, for cancer treatment, where high magnetic anisotropy energies are required at the nanoscale. However, deeper knowledges of the fine mechanisms playing a significant role on the magnetic anisotropies existing in the nanospinels are necessary to help the creation of rationalized materials with controlled magnetic anisotropies for the requirement of the system. In this thesis, we have used X-ray Magnetic Circular Dichroism (XMCD) as an original approach for probing the magnetic anisotropies and magnetic couplings of nanospinels obtained in ferrofluids. The nanoparticles are iron bearing spinels for which cobalt ions have been introduced in the spinel structure of the nanoparticles as a true makers of magnetic anisotropy. First, magnetic nanospinels have been synthesized by tuning their size and composition and using different synthesis processes. XMCD investigations revealed that the coercive field of the nanospinels is governed by the concentration of Co2+ ions sitting in octahedral sites of the spinel structure, and this can be directly linked to some synthesis parameters. Then, we have investigated core@shell nanoparticles, which can be synthesized with an appropriate choice of magnetic anisotropies for the core and the shell in order to tailor optimal magnetic properties. In the case of MnFe2O4@CoFe2O4, our findings reveal that the very thin CoFe2O4 shell imposes a strong magnetic anisotropy to the otherwise very soft MnFe2O4 core. The other class of ferrofluids that has been investigated during this thesis are binary ferrofluids that are constituted of two different types of magnetic nanoparticles. For such systems, the carrier liquid must be preserved to understand the magnetic interactions in the ferrofluid as they are. Another motivation of this thesis was thus to extend XMCD to the in situ investigation of the nanospinels dispersed in ferrofluids. We have been started a liquid cell development in the DEIMOS beamline at SOLEIL. The setup is still in progress and is aimed at being compatible with soft X-Rays short penetration depth and ultra-high vacuum environment. Hard X-ray photon-in/photon-out spectroscopy coupled to XMCD (1s2p RIXS-MCD) can be a very valuable alternative to soft X-ray XMCD at K-edge of 3d elements when liquid cell sample environment is required. The instrumental development of a liquid cell used with 1s2p RIXS-MCD spectroscopy allowed us to investigate the nanoparticles directly in the ferrofluids revealing interparticles magnetic couplings in binary ferrofluids
Lin, Tsui-Hsun. "Birefringence, Anisotropic Shrinkage and Luminance in Injection Molded Light-Guide Plate: Modeling and Experiment." Akron, OH : University of Akron, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1232005891.
Повний текст джерела"May, 2009." Title from electronic dissertation title page (viewed 11/27/2009) Advisor, Avraam I. Isayev; Committee members, James L. White, Thein Kyu, Kevin Kreider, Shi-Qing Wang; Department Chair, Sadhan C. Jana; Dean of the College, Stephen Cheng; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
Solomon, Brian R. (Brian Richmond). "Butterflies and batteries : advances in liquid repellent surfaces by anisotropic wetting and lubricant impregnation." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104129.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 119-130).
Recent advances in creating liquid-repellent surfaces have focused on decreasing the interaction between a liquid and a solid surface by modifying the surface's chemistry and cleverly designing its geometry on nano- and millimetric length scales. This thesis explores two advances to control a liquid's interaction with a surface: 1) deflectable structures that influence anisotropic wetting properties and 2) lubricant impregnated surfaces comprised of a porous surface and liquid lubricant. Through experimental characterization the mechanism by which deflectable scales on a butterfly wing cause anisotropic drop repellency is investigated. The design of lubricant impregnated surfaces is reviewed and expanded by demonstrating their potential for drag reduction and incorporation into electrochemical systems. The first part of this thesis characterizes how the unique structure of a butterfly's wings contributes to its anisotropic wetting properties. In particular, a water drop placed on the surface of a butterfly's wing will easily roll away from the butterfly's body, but will roll off at much higher angles toward the body. This phenomenon is observed and quantified using environmental electron microscopy and confocal microscopy. A theory that takes into account the deflection of the butterfly's scales explains the observed anisotropy and correlates with the observed roll-off on a wide range of butterfly species. Such deflectable surface structures offer a new way to tune the wetting properties of a surface. The second part of this thesis reviews and expands on lubricant impregnated surfaces. It explains how to achieve a stable lubricant impregnated surface and discusses its basic features including the wetting ridge and lubricant cloak. Motivated by the slippery nature of these surfaces, the potential of lubricant impregnated surfaces to reduce drag is detailed. A scaling model that incorporates the viscosity of the lubricant and elucidates the dependence of drag reduction on the ratio of the viscosity of the working fluid to that of the lubricant is presented. The model is validated by experiments conducted in a cone and plate rheometer where a drag reduction of 16% is measured. Finally, lubricant impregnated surfaces are applied to electrochemical systems. Measurements quantify how lubricant impregnated surfaces improve the flowability of a non- Newtonian lithium polysulfide flow electrode in which electronic conductivity is imparted by carbon particles. A framework for the design of such surfaces for a wide range of flow electrode solvents is used to incorporate lubricant impregnated surfaces into a Gravity Induced Flow Cell (GIFCell) prototype to enable the flow of highly conductive suspension.
by Brian R. Solomon.
Ph. D.
Oliveira, Luma Melo de. "The influence of the Ionic Liquid [C14MIM][Cl] on the structural and thermodynamic features of zwitterionic and anionic model membrane." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-11052017-111842/.
Повний текст джерелаOs líquidos iônicos (LI) tem atraído grande atenção, tanto da academia quanto da indústria, devido às suas numerosas aplicações. LI são sais, normalmente compostos por um íon orgânico, e um contra-íon que pode ser orgânico ou inorgânico, mas que tem como característica ser encontrado no estado líquido à temperaturas próximas a ambiente. Nosso interesse em estudar LIs vem de sua baixa toxicidade, atribuída a sua baixa volatilidade. Entretanto, alguns estudos recentes mostraram que a toxicidade dos LI é maior do que se acreditava, em particular com sistemas de relevância biológica.O objetivo principal desta dissertação é estudar a influência do líquido iônico 1-tetradecil-3-metilimidazólio cloreto ([C14MIM][Cl]) com sistemas de membrana. Para isso, utilizamos diferentes lipídios, como o POPC, esfingomielina, colesterol, POPG, DPPC,DPPG e o DMPC. Para cada um destes sistemas, a influência da concentração de LI foi elucidada por meio de um estudo sistemático através de diferentes técnicas experimentais, tais como: espalhamento de raio-X a baixos ângulos (SAXS), espalhamento dinâmico de luz (DLS), anisotropia de fluorescência, microscopia óptica e potencial-z. Uma vez que o componente iônico de [C14MIM][Cl] tem uma carga positiva no grupo imidazólio, a carga superficial de todas as vesículas estudadas aqui aumentou. Entretanto, para asvesículas compostas pelos lipídeos zwitteriónicos, não tenha sido observada qualquer alteração significativa no tamanho e na temperatura de transição de fase gel-fluido. O [C14MIM][Cl] altera a organização interna entre as moléculas de lipídio com carga negativa. Consequentemente, à medida que a quantidade de LI aumenta, a temperatura de transição de fase diminui e o tamanho médio das vesículas aumenta. Para o sistema DPPC:DPPG (1:1) a temperatura de transição de fase caiu de 42.50 ± 0.13 oC para 25.27 ± 0.33 oC e para as vesículas de DPPG de 46.12±0.22 oC para 36.6±0.38 oC. Quanto ao diâmetro hidrodinâmico médio, no caso do DPPG este valor aumentou de 84±0.1 nm para 176±0.1 nm, enquanto que para a mistura DPPC:DPPG (1:1) ele passou de 95±0.1nm para 196±0.1nm. Indicando assim que o LI incorpora na bicamada lipídica negativamente carregada. O perfil de densidade eletrônica, obtido por SAXS, confirma a penetração do [C14MIM][Cl] na bicamada lipídica. Diferentemente, para a membrana lipídica zwitteriónica o LI tende a se situar perto da região da cabeça polar sem afetar significativamente a região do interior da bicamada lipídica. Por outro lado, a presença de15 mol% de [C14MIM][Cl] aumenta a espessura da região polar das bicamadas das vesículas de DPPC de ~ 11.1±0.6 Å para ~ 18.0±0.7 Å. Os resultados qualitativos da microscopia óptica mostraram que a incorporação da LI desestabiliza a assimetria da membrana entre as camadas interna e externa, além de sugerir o aparecimento de poros (evidenciado pela perda do contraste ótico das vesículas) e estruturas chamadas de buds. Esperamos que este trabalho melhore a compreensão dos efeitos do LI na presença de organismos biológicos.
Daveze, Pascal. "Contribution à l'étude des propriétés magnéto-optiques des liquides magnétiques : applications opto-électroniques." Saint-Etienne, 1996. http://www.theses.fr/1996STET4008.
Повний текст джерелаNagy, Zsuzsanna tamara. "Synthesis of self-organized dendrimers and dendronized nanohybrids and their physical properties." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAE020/document.
Повний текст джерелаThe need to expand further the range of mesomorphic organization, develop original materials where different functionalities can be added (i.e. multifunctional), and to design “multitask materials” with tunable properties are particularly interesting and crucial challenges for potential uses in future technologies. On the one hand, we focused on the design and synthesis of multifunctional materials (liquid crystalline, dendritic, photoresponisve) which are suitable for making thin films where photoinduced optical anisotropy and surface relief gratings can be generated. The mesomorphic behaviour of these dendrimers was investigated and also their optical properties. On the other hand, we grafted structurally related protodendritic mesogenic ligands to monodisperse gold nanoparticles to elaborate liquid crystalline hybrids in order to self-organize NPs in periodic arrays. A set of dendronized gold nanohybrids was synthesized to carry out this study
Isoppo, Eduardo de Almeida. "Estudo do efeito da adição do sal cloreto de césio (CsCI) na formação de novas estruturas no sistema binário, amônio pentadecafluorooctanoato/água deuterada (APFO/D2O) em amostra com baixa concentração de APFO." Florianópolis, SC, 2008. http://repositorio.ufsc.br/xmlui/handle/123456789/91577.
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Estudamos, basicamente, os efeitos da adição de um sal eletrolítico monovalente forte, como o cloreto de césio (CsCl), na formação de novas estruturas na fase isotrópica micelar da mistura binária amônio pentadecafluorooctanoato e água deuterada (APFO/D2O) em baixas concentrações de APFO. Investigamos, também, a influência que o sal CsCl produz na forma e tamanho dos agregados micelares bem como sua dependência com a temperatura. Diversas técnicas experimentais ópticas foram usadas e dos resultados destas medidas, temperaturas de transições de fases foram determinadas com grande precisão e uma estrutura, formada por vesículas, foi identificada. Estas vesículas são induzidas espontaneamente na solução simplesmente pelo efeito do sal adicionado, isto é, sem a necessidade de qualquer método específico para obte-las.
Atherton, Timothy James. "Frustration phenomena due to elastic anisotropy in thin liquid crystal films." Thesis, University of Exeter, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436421.
Повний текст джерелаWilson, Mark James. "The effect of molecular anisotropy on the properties of liquid crystals." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285765.
Повний текст джерелаKonopka, Amy Elizabeth. "The Effect of Anisotropy on In-Plane liquid Distribution in Nonwoven Fabrics." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010925-125929.
Повний текст джерелаAbstractKonopka, Amy Elizabeth. The Effect of Anisotropy on In-Plane liquid Distribution in Nonwoven Fabrics. (Under the direction of Behnam Pourdeyhimi)Anisotropy has been shown to be an influencing factor of many nonwoven structural properties such as the bending rigidity and the tensile strength. The effect on liquid distribution (a very important property in many nonwoven applications), however, has not been determined. In this study the effect on anisotropy on a material's in-plane liquid distribution is examined. By using the new NCRC GATS device, which enables the in-plane liquid distribution and the recording of the spread to occur simultaneously, it was determined that the liquid distribution was indeed influenced by the structural anisotropy. Also determined was the effect of the testing method on the wicking rate of the material. A comparison between conventional test methods and a newly developed test method, which utilizes the NCRC GATS and a hollowed plate, were made. It was determined from the results that the new method is the only method that measures the intrinsic wicking of the material.
Aquino, da Silva de Souza Renata. "Síntese, caracterização magnética e magneto-ótica de colóides magnéticos à base de ferrita de manganês e de maguemita dopada com átomos de metais terras raras visando aplicações biomédicas : nanoradioterapia." Paris 6, 2003. http://www.theses.fr/2003PA066403.
Повний текст джерелаHakobyan, Davit. "Spin-orbit optomechanics of space-variant birefringent media." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0081/document.
Повний текст джерелаThis work focuses on angular optomechanics driven by the spin-orbit interaction of light, using inhomogeneous and anisotropic media as model systems and different kinds of such material systems are considered in practice. In particular, we use nematic liquid crystal defects and report on the direct experimental observation of spin-orbit optical radiation torque that leads to distortion of molecular orientation pattern of the defects. Then, by using solid-state spin-orbit couplers of arbitrary order made of artificially nanostructured glasses, we unveil an optical torque reversal phenomenon that is the angular counterpart of so-called optical negative forces. This counterintuitive optomechanical effect is experimentally retrieved, in an indirect manner, via rotational Doppler frequency shift experiments. Finally, we report on our attempts to build up an experimental framework allowing the direct observation of optical torque reversal. Several options are considered, which include both metallic and dielectric approaches and involve sample miniaturization that has been explored at the millimeter and micrometer scale
Okrasa, Lidia. "Relaxations moléculaires de composites polymères anisotropes à base de dérivés cellulosiques cristaux liquides." Lyon 1, 1999. http://www.theses.fr/1999LYO10021.
Повний текст джерелаPottié, Laurence. "Réseaux anisotropes par réticulation de monomères diepoxy cristaux liquides orientés sous champ magnétique." Paris 6, 2005. http://www.theses.fr/2005PA066634.
Повний текст джерелаFLAMENT, CYRILLE. "Etude de phases ordonnees bidimensionnelles dans des films de langmuir : structure d'un cristal anisotrope parametre d'ordre et module d'elasticite d'un cristal-liquide." Paris 7, 1994. http://www.theses.fr/1994PA077031.
Повний текст джерелаLi, Liang-shi. "Anisotropy in CdSe quantum rods." Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/827094-DOIqqD/native/.
Повний текст джерелаPublished through the Information Bridge: DOE Scientific and Technical Information. "LBNL--55023" Li, Liang-shi. USDOE Director. Office of Science. Office of Basic Energy Sciences (US) 09/01/2003. Report is also available in paper and microfiche from NTIS.
Thiebaut, Olivier. "Bicouches orientées de cristaux liquides colonnaires pour applications photovoltaïques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-00591978.
Повний текст джерелаAlvarez, Salgado Francisco. "Applications des milieux anisotropes à la détermination de structures de biomolécules par RMN liquide." Versailles-St Quentin en Yvelines, 2005. http://www.theses.fr/2005VERS0035.
Повний текст джерелаThe structural study of biological macromolecules (DNA, proteins, complexes. . ) by high resolution NMR is based in the use of various structural data: distances between atoms of hydrogens lower than 5 Å (nuclear Overhauser effect), dihedral angles (obtained by the measure of scalar coupling constants) and chemical shift indexes or hydrogen bounds for the characterization of secondary structures. The set of these structural constraints represents a local information and so when one predicts the global fold of a structure, they can be responsible for accumulation of uncertainties on the macromolecule structure. A solution for landing of this undetermination consists in resorting to in long distances as a supplement to usual ones. These data are defined with regard to a molecular frame and are obtained by measuring residual dipolar couplings (RDC) resulting from the weak orientation of the macromolecule (parameter of order 10-3 to 10-5). At first, we studied two structures of LewisX oligosaccharides by mean of the RDC. The purpose of this study was to show the capacity of the RDC to define a structure. In the second part of this study, we precised the location of a helix in the double tudor domain 53BP1 by using RDC restraints. The last part of this work, was based on the structural study of various DNA fragments by using three sets of constraints of RDC (PEG, Bicelles SDS and PF1) detect a structural deformation
Heiderich, Anne. "Diffusion multiple en milieu non linéaire ou anisotrope." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10200.
Повний текст джерелаDone, Dinshong. "Studies on the rheology and morphology of thermotropic liquid crystalline polymers." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/77792.
Повний текст джерелаPh. D.
Géminard, Jean-Christophe. "Croissance libre de la phase colonnaire hexagonale d'un cristal liquide discotique." Lyon 1, 1993. http://www.theses.fr/1993LYO10128.
Повний текст джерелаBéguin, Laetitia. "Développements méthodologiques en RMN pour la simplification de la mesure des couplages spin-spin : applications en solvant isotrope et anisotrope." Paris 11, 2010. http://www.theses.fr/2010PA112294.
Повний текст джерелаThe goal of this thesis was the development of new NMR methodology to visualize simply and quickly the enantiomeric differentiation in chiral liquid crystals and the simply measure of spin-spin coupling. Ln a first time, we have made a non-exhaustive presentation of liquid crystals and the use of Iiquid crystals in NMR. Next, we have developed and optimized a proton experiment that permits the simply and precise measure of one proton proton coupling: the SERFph sequence. We associate this sequence with rotation around magic angle to release selective pulse using. We have next generalized this sequence to measure the entire coupling between one proton and all molecular protons. For this, we have used spatial encoding technical from NMR imaging. Combining a selective pulse with a pulse field gradient, we have been able to excite different proton in different slice of the sample and then we have made simultaneously different SERFph experiments. Finally, we have optimized heteronuclear one bond coupling measure. For that, we have taken for starting point the J-1H-HSQC-BIRD sequence, developed in our laboratory. We added chemical shift evolution during F1 dimension to spread out the information in this dimension. This dispersion should permit the extraction of heteronuclear couplings of complex proton spectra
Dessombz, Arnaud. "Elaboration et caractérisation de phases cristal liquides de suspensions de rutile (TiO2). Propriétés physiques anisotropes." Phd thesis, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00354476.
Повний текст джерелаLe travail présenté montrera comment il est possible d'élaborer par Chimie Douce des nanoparticules anisotropes afin d'obtenir en milieu aqueux une mésophase, de nature nématique, et de la caractériser. De plus, des suspensions de bâtonnets, même relativement diluées, s'orientent sous cisaillement, ce qui permet de produire par spin-coating des films anisotropes. Ces films sont des échantillons de choix pour effectuer des mesures, sous irradiation ultraviolette, de photocatalyse d'espèces organiques dissoutes ou encore de photoconduction. Ces mesures peuvent être comparées avec les résultats obtenus à l'aide d'un monocristal de TiO2 présentant les mêmes facettes cristallographique [110] que les nanoparticules.
Un film orienté de bâtonnets de rutile présente naturellement des propriétés anisotropes. En outre, nous avons mis en évidence une forte dépendance des propriétés catalytiques et de la conductivité électronique avec la polarisation de l'irradiation ultra-violette. Nous montrerons dans quelle mesure la théorie des bandes permet d'expliquer ces effets.
Charlet, Emilie. "Mouillage et orientation d’un film mince de cristal liquide colonnaire : de la détermination des propriétés optiques aux applications photovoltaïques." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13653/document.
Повний текст джерелаThis thesis deals with columnar liquid crystal studied in the geometry of open supported thin films. Columnar liquid crystals are usually made of disk-shaped molecules derived from aromatic dyes. They are efficient charge transporters with the added capacity to self-assemble in large oriented domains. Consequently, such materials may be used in photovoltaic devices. In order to benefit from their good uniaxial charge mobility, their organization has to be controlled in uniform oriented thin films in the range of thicknesses of typically 100 nm. Homeotropic alignment (columns normal to the interface) is required for solar cells whereas uniaxial planar anchoring (columns parallel to the interface) is needed for applications such as polarizers or organic field effect transistor. Different methods to monitor the alignment in open thin films have been developed in this work, which make possible to achieve either homeotropic anchoring by a specific thermal treatment, or uniaxial planar orientation using a Teflon layer. Based on these orientation skills, a uniform ultra-thin film, free of dewetting and homeotropically oriented, is achieved (down to 50 nm thick) opening the way towards efficient solar cells, and a complete study of the optical properties has been performed (with the determination of the anisotropic complex indices) for different columnar liquid crystals. The dynamics of dewetting and the equilibrium state of a thin supported film have also been investigated. Experimental results show the formation of anisotropic droplets and reveal a nanometric film during dewetting
Wen, Chien-Hui. "High Birefringence and Low Viscosity Liquid Crystals." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3206.
Повний текст джерелаPh.D.
Other
Optics and Photonics
Optics
Riaud, Antoine Jean-Pierre René. "Etude des potentialités offertes par la synthèse de champs d'ondes acoustiques de surface pour l'actionnement de liquides et la manipulation sans contact." Thesis, Ecole centrale de Lille, 2016. http://www.theses.fr/2016ECLI0010/document.
Повний текст джерелаWhen surface acoustic waves radiate in nearby fluids, they trigger two nonlinear effects: acoustic radiation pressure and acoustic streaming. These two effects find numerous applications for digital microfluidics, contactless manipulation and biological cell sorting. Nonetheless, these systems face two limitations. On the one hand, each application requires a specific acoustic wave: there is no multifunction device so far. On the other hand, search for functionalities offered by simple surface acoustic waves (plane and focused waves) has failed to provide a selective tweezers able to manipulate individual particles or cells independently of their neighbors. In the first part of this thesis, we develop two methods to synthesize complex surface acoustic wave fields. The first one employs an array of 32 interdigitated transducers controlled by the inverse filter to generate arbitrary fields on demand. The second method solves an inverse problem to design a holographic transducer to generate a predefined field. In the second part of the thesis, we use the inverse filter to (i) implement a multifunction lab on a chip and (ii) investigate the potentialities of a special type of surface acoustic waves called swirling surface waves. These waves enable a selective and contactless manipulation of microscopic objects. We conclude the thesis by integrating a holographic acoustical vortex transducer on a microscope in order to selectively manipulate biological cells without contact
Agra-Kooijman, Deña Mae G. "Liquid Crystal Alignment and Relaxation Dynamics at Surface Modified Thin Polymer Films." Kent State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=kent1228148263.
Повний текст джерелаMacdonald, Brian Fraser. "Reflection anisotropy spectroscopy and scanning probe microscopy studies with applications to liquid crystal alignment layers." Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/11081.
Повний текст джерелаWu, Liang. "Modelling liquid crystalline ordering in anisotropic and inhomogeneous fluids : from simple models of rod- and disc-like particles to polypeptides." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14620.
Повний текст джерелаLafontaine, Eric. "Résonance magnétique nucléaire haute résolution en milieu cristal liquide cholestérique." Paris 11, 1989. http://www.theses.fr/1989PA112405.
Повний текст джерелаHe, Kunyun. "Vers la production de 'patchy particles' à base de cristaux liquides." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLET002.
Повний текст джерелаOne main goal of modern material science is to produce complex three-dimensional architectures from the self-assembly of pre-designed colloidal building blocks. Developing methods to produce colloidal particles capable to interact in complex ways is crucial in this perspective. This thesis describes a new strategy in which liquid crystals are used for producing anisotropic colloidal particles. These new particles are double emulsions where a nematic liquid crystal is confined to a spherical shell, the geometry of which imposes the presence of topological defects. The number and position of the defects set the valence of the particles as well as the directionality of the eventual bonds between them. Our study aims at fabricating such liquid crystal shells in a controlled way, both in terms of size and defect structure. We describe the standard microfluidic methods used to produce liquid crystal shells and test their operational limits. We show that the standard microfluidic techniques do not allow for scaling the system down to the colloidal scale. We then present a new microfluidic set-up which improves our capability of producing shells in a large range of sizes at high frequencies. Combining experiments and numerical simulations, we study the possibility of inducing transitions between different valence states through a continuous variation of the shell geometry. Finally, we study a lyotropic chromonic liquid crystal, which exhibits a large elastic anisotropy in the nematic phase. We study how this exotic nematic liquid crystal responds to confinement and curvature and investigate the new emerging symmetries
Saliba, Sarmenio. "Thermotropic and lyotropic liquid crystals for the formation of zinc oxide nanohybrids." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1598/.
Повний текст джерелаThe work presented in this manuscript describes the incorporation of inorganic materials inside organic hosts. Our ambition was to successfully hybridize ZnO nanostructures with liquid crystals. This was achieved using different strategies, the choice of which depended on the desired properties of the final material. The objective was not only the synthesis and stabilization of the nanoparticles within, but also their organization in the LC medium. One approach was the functionalization of preformed ZnO spherical nanoparticles by thermotropic LC ligands. This was made possible using a ligand exchange mechanism. Due to a dynamic equilibrium at the surface of ZnO NPs, the mesogenic molecules could exhibit order at the molecular level, giving rise to novel LC/NP hybrids with enhanced LC properties. The organization of NPs could also be induced by the use of lyotropic liquid crystals. In this case, the NPs were not simply doped into a LC material, but synthesized directly inside the lyotropic phases. The synthesis of ZnO was therefore confined to domains of defined size and shape which can directly control the organization of the nanostructures growing within. Apart from organization of NPs, our constant objective was the fabrication of anisotropic nanoobjects via LC-assisted synthesis. Thermotropic liquid crystals consisting of novel low molecular weight branched mesogens have proved to be remarkable templates for anisotropic growth of ZnO nanocrystals. This anisotropic growth was also found to be influenced by the size of the LC molecules as observed with the fabrication of ZnO inside LC polymers. This work has shown the possibility of integrating inorganic material in LCs providing that the two constituents are able to sufficiently interact with one another