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Showing 1 to 20 of 178 for “"Nematic"”.
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Mathematical models for polymer-nematic interactions
… a mathematical model that consists of a nematic liquid crystal layer sandwiched between two parallel bounding plates, across which an external field may be applied. Particular attention is paid to the effect of an applied field on the layer as well as the interaction between the liquid …
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Disclinations in Homogeneously Deformed Nematic Elastomers
A nematic elastomer is a rubber-like solid formed by cross-linking of a polymeric fluid that includes nematic liquid crystalline molecules as side- or main-chain elements. This thesis explores issues concerned with disclinations---which are tubular neighborhoods in which the material is isotropic …
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Nanoparticle-chiral nematic liquid crystal composites
… magnetooptical nanoparticles with a chiral nematic liquid crystal. The fabrication of this material system was advanced through two distinct phases of research. The first phase seeks to produce magnetooptical yttrium iron garnet (YIG) nanoparticles with an average diameter on the order of …
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On the Continuum-Mechanics of Nematic Elastomers
A nematic elastomer is a rubber-like solid formed by the cross-linking of a polymeric fluid that includes nematic liquid crystalline molecules. We develop a continuum theory with the basic kinematic ingredients being the deformation of material particles and the orientation of the nematic …
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Statistical physics of isotropic-genesis nematic elastomers
"Isotropic-genesis nematic elastomers (IGNEs) are materials that exhibit fascinating properties such as a remarkable softness in elasticity and do not undergo long-range nematic ordering, even at low temperatures. These materials are formed via the following process. Consider a melt or solution of …
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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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Mathematical models for bistable nematic liquid crystal displays
… on theoretical models of a possible bistable nematic device, whose operating principle relies on controlling surface anchoring conditions. Switching between the two stable steady states is achieved by application of a transient electric field. A 1D model is considered first, and means are …
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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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Instabilities in newtonian films and nematic liquid crystal droplets
The instabilities of Newtonian films and nematic liquid crystal droplets within the framework of the long wave (lubrication) approximation are studied. For Newtonian films, it is found that, under destabilizing gravitational force, a contact line, modeled by a commonly used precursor film model, …
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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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ELECTRO-OPTICAL AND ELECTRO-MECHANICAL RESPONSE OF FERROELECTRIC NEMATIC FLUIDS
The recent discovery of the ferroelectric nematic (NF) phase opened a brand-new field of explorations in liquid crystal science thanks to new physical effects, resulting from the polar nature of this novel mesophase. Indeed, the electrical and optical properties of NF phase, in which molecules …
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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
… consider the director structures of inactive nematic liquid crystals confined in rectangular regions. We use a mixture of analytical and numerical calculations to examine the energies of non-trivial nematic equilibria which exchange stabilities with constant equilibria at critical anchoring …
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Electric field controlled optical scattering in nematic liquid crystal films.
Thesis. 1975. B.S. cn--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
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CRITICAL DYNAMICS OF LIQUID CRYSTAL ABOVE THE ISOTROPIC - NEMATIC PHASE TRANSITION
Dynamics of liquid crystals above the isotropic-nematic phase transition point is studied. The phase transition is of first-order, but nearly critical. Near the transition point the correlation length (zeta) of molecular orientational order could be comparable to the inverse of a light scattering …
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