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Showing 1 to 20 of 29 for “"Nematic liquid crystals"”.
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Nonlinear optical effects in nematic liquid crystals
… studies of nonlinear optical effects in nematic liquid crystals including degenerate four-wave mixing are presented. The optically induced Freedericksz transition which is essential for these effects is also described. Experimental investigations are performed using a homeotropically …
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Optically induced orientational transitions in nematic liquid crystals
… by intense light in homeotropically oriented nematic layers. A large number of experiments has been performed in such systems and various interesting dynamical regimes have been identified. However, systematical theories capable of describing the observed phenomena have been derived for some …
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Nematic liquid crystals for nano-structured organic photovoltaic
A range of novel liquid crystals and amorphous organic conjugated semiconductors were synthesised by the chemistry branch of the Organophotonics group at Hull University. These compounds are studied electrochemically and optically to investigate the suitability of these materials as good …
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Emission properties of radiative chiral nematic liquid crystals
… (DOS) of the normal modes in dye-doped chiral nematic liquid crystal (LC) cells in the presence of various loss mechanisms. Losses and gain are incorporated into the transmission characteristics through the introduction of a small imaginary part in the dielectric constant perpendicular and …
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Band edge lasing in chiral nematic liquid crystals
… there has been considerable interest in chiral nematic liquid crystal band edge lasers. The birefringent molecules of chiral nematic liquid crystals form a periodic helical structure, which results in a photonic bandgap for circularly polarised light with the same sense of rotation as the helix. …
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Microfluidic flow of colloidal particles in nematic liquid crystals
… on the behaviour of colloidal particles in nematic liquid crystal flow for a wide range of parameters in microfluidic channels and ducts. We study the change in structure of defects and molecular orientation around a static particle, particle migration in microfluidic channels, morphology of …
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Nonlinear optical studies of dye-doped nematic liquid crystals
Nematic liquid crystals possess large optical nonlinearities owing to their large refractive index anisotropy coupled with the collective molecular reorientation. Doping absorbing dyes into liquid crystals increases their optical responses significantly due to increased absorption in the visible …
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Investigation of flexoelectricity and ionic contamination in nematic liquid crystals
The work presented is a study of nematic liquid crystal physical properties. One of the phenomenon investigated is the bistability or in other words, the ability of the director of the material to rest in different orientations as function of the geometry of the sidewall. The main core of this …
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Mathematical modelling of active nematic liquid crystals in confined regions
… continuum theories and modelling techniques of liquid crystalline fluids to the area of anisotropy and self-organisation derived from active agents. The research involves a continuum description of anisotropic active fluids, using adapted forms of continuum hydrodynamic theories of liquid …
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The dynamics of strings, monopoles, and texture in nematic liquid crystals
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1991.
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Simulations of interfacial dynamics of complex fluids using diffuse interface method with adaptive meshing
… in this thesis include viscoelastic fluids and nematic liquid crystals. Viscoelasticity is represented by the Oldroyd-B model, derived for a dilute polymer solution as linear elastic dumbbells suspended in a Newtonian solvent. The Leslie-Ericksen model is used for nematic liquid crystals，which …
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Pattern Formation in Active Nematics
… studies of the nonequilibrium dynamics of active nematic liquid crystals. Active nematics are a new class of liquid crystals consisting of elongated rod-like units that convert energy into motion and spontaneously organize in large-scale structures with orientational order and self-sustained …
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The effect of shear flow on the isotropic-nematic transition in liquid crystals
… the effects of shear flow on the Isotropic-Nematic phase transition in liquid crystals. Shear flow has dramatic orienting effects on the rod-like constituents of nematic liquid crystals, with the general effects of (1) inducing order in the high-temperature isotropic phase, and (2) dictating …
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The role of topological defects and textures in the kinetics of phase ordering
… in nature. The two systems investigated are (i) nematic liquid crystals, which support topologically stable abelian (in the uniaxial nematic case) and non-abelian (in the biaxial nematic case) singular defects, and (ii) the O(3)-symmetric vector (i.e., Heisenberg-type) system in 2 spatial …
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Electrical and optical effects in hybrid liquid crystal cells
… electrical and optical effects in hybrid liquid crystals. Hybrid form of liquid crystals was achieved by using photoconducting alignment layers in liquid crystals cells and also by including ferroelectric, inorganic nanoparticles in the liquid crystal bulk. Such liquid crystal systems show …
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Design and synthesis of suitable phototriggers for a chiroptical liquid crystal switch
… applications as phototriggers for a chiroptical liquid crystal switch were investigated via several approaches. Chiral exciton coupling theory was first used to design and synthesize a series of axially chiral arylmethylene cyclohexanes in both racemic and optically active forms for use as …
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Order reconstruction and solution landscapes for liquid crystalline systems
Liquid crystals are the surprisingly less well known fourth phase of matter, sitting between the familiar solid and liquid phases. These materials combine fluidity with orientational and/or positional order, yielding surprising and desirable properties relevant for use in tailor-made applications. …
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Capillary Assembly Of Microparticles On Curved Fluid Interfaces
… of microcylinders on a thin film of uniform nematic liquid crystals. In all the studies described above, interface curvature, in particular, finite deviatoric curvature plays a central role in assembly and in guiding structure formation. The concepts studied here are fundamental and provide …
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Nuclear magnetic resonance and rheo-NMR investigations of wormlike micelles, rheology modifiers, and ion-conducting polymers
… wormlike micelle solutions, which behave as nematic liquid crystals at sufficiently high concentration. Amphiphilic solutions of this type are used in myriad applications, from fracturing fluids in oil fields to personal care products. We investigated the phase behavior and dynamics of shear …
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