Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 344 for “"liquid crystal"”.
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Cyclic polymer liquid crystal structures.
Recent advances in liquid crystal research have included the synthesis of polymeric materials which contain liquid crystalline moieties. The work presented here concerns the study of the structure-property relationships of a particular group of liquid crystalline polymers in which the polymer …
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Polarization-independent Liquid Crystal Devices
Liquid crystal (LC) devices can be operated as amplitude modulators and phase modulators. LC amplitude modulation is commonly used in liquid crystal display (LCD) while phase-only modulation is useful for laser beam steering, tunable grating, prism, lens, and other photonic devices. Most LC devices …
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Fast Response Liquid Crystal Devices
Liquid crystal (LC) has been widely used for displays, spatial light modulators, variable optical attenuators (VOAs) and other tunable photonic devices. The response time of these devices is mainly determined by the employed liquid crystal material. How to obtain fast response for the LC devices is …
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Tunable Liquid Crystal Photonic Devices
Liquid crystal (LC)-based adaptive optics are important for information processing, optical interconnections, photonics, integrated optics, and optical communications due to their tunable optical properties. In this dissertation, we describe novel liquid crystal photonic devices and their …
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Lattice modelling of liquid crystal mixtures
… of the phase behaviour of binary and ternary liquid crystals mixtures represented using the LebwohlLasher lattice model. The binary mixture is studied in the Canonical and Semi Grand Canonical Ensembles over a comprehensive set of temperatures, concentrations and the relative coupling …
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Wide Viewing Angle Liquid Crystal Displays
… of wide viewing angle and high transmittance liquid crystal displays. First, a design of wide viewing angle liquid crystal displays utilizing crossed linear polarizers is proposed. The designed multi-domain vertical-alignment liquid crystal display predicts superb contrast ratio over wide …
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Studies Of Liquid Crystal Response Time
… dissertation, the response time issue of the liquid crystal (LC) devices is investigated in meeting the challenges for display and photonic applications. The correlation between the LC director response time and the optical response time is derived theoretically and confirmed experimentally. A …
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Liquid crystal adaptive planar optical devices
… a series of experimental studies based on using liquid crystals (LC) with planar optical lightwave components. Adaptive optical devices have been fabricated by combining LCs with direct UV written buried channel waveguide and Bragg grating structures. It has been discovered that the hysteresis …
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Photo-responsive liquid crystal block copolymers/
Photo-responsive liquid crystal polymers (LCP) which contain azobenzene moieties have gained interest for their ability to change properties by merely irradiating them with the correct wavelength of light in the appropriate temperature range. Furthermore, they have been crosslinked for elasticity …
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Nanoparticle-chiral nematic liquid crystal composites
… of the fabrication of a one-dimensional photonic crystal without time-reversal and space-inversion symmetries was pursued. Theoretical studies predict that such a system would exhibit unusual optical properties, including indirect photonic band gaps and backward wave propagating eigenmodes. Such a …
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The rheology of liquid crystal polymer blends.
… and explanation of the interaction between liquid crystal and isotropic polymers. An investigation of the rheological behaviour has been carried out on blends containing small additions of a main chain thermotropic liquid crystal polymers using capillary rheometry. Samples of these blends …
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Liquid crystal films confined between patterned substrates.
In this thesis, systems of nematic liquid crystals confined between patterned substrates have been studied using molecular computer simulation. The aim of this work, done in parallel with experimentalists in Leeds, has been to investigate the use of chemical patterning as a novel method for …
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Direct liquid crystal templating of mesoporous silica
… silicas by direct templating from lyotropic liquid crystal phases of the<br/>surfactants Pluronic PI23, Pluronic F127, CTAB and Brij 78. The factors affecting the<br/>regularity, morphology, pore diameter and wall thickness of the templated mesoporous<br/>silicas were examined by exploring …
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Light–matter interaction in liquid crystal cells
… between light and matter in photorefractive liquid crystal<br/>cells. To model the liquid crystal alignment we develop a fast and accurate approximation of<br/>the normally stiff equations which minimise the Landau-deGennes free energy of a nematic<br/>liquid crystal. The resulting equations …
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Liquid Crystal Mediated Bioassay for Protein Detection
… a HSA assay by incorporating a thin layer of liquid crystals (LCs) as a readout system such that the presence of HSA in urine samples can be detected as optical signals. In combination with dilution protocols, the assay can be used to estimate the concentration range of HSA simply by counting …
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Reconfigurable tunable microwave devices using liquid crystal.
… In this thesis, the anisotropic properties of liquid crystals in their nematic phase are exploited as a low-voltage (< 35 V) mechanism for designing tunable wireless devices at a low microwave frequency (L to C-band). To demonstrate the possibility of using liquid crystal technology, three …
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A molecular dynamics study of liquid crystal mixtures.
… from molecular dynamics simulations of binary liquid crystal mixtures using a generalisation of a well established Gay-Berne intermolecular potential. The simulations are undertaken in both the microcanonical (NVE) and the isoenthalpic-isobaric (NPH) ensembles. Firstly a 50:50 mixed system is …
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Low Absorption Liquid Crystal Materials for Midwave Infrared
Liquid crystal is an amazing class of soft matters with applications spanning from visible, infrared, millimeter wave, to terahertz. In addition to direct-view displays and projection displays, liquid crystal is also widely used in adaptive optics, tunable-focus lens, and laser beam steering. …
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Mathematical models for bistable nematic liquid crystal displays
Bistable Liquid Crystal Displays (LCDs) offer the potential for considerable power savings, compared with conventional (monostable) LCDs. The existence of two (or more) stable field-free states that are optically-distinct means that contrast can be maintained in a display without an …
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