9,574 research outputs found
Coleridge, Robert Boyd and Rosalind. July 18, 2014. Crystal Braye interviewing Boyd and Rosalind Coleridge, Trinity.
No full textBoyd and Rosalind Coleridge discuss growing up in Trinity and Trouty; farming, including growing potatoes, carrots, cabbage, turnip, savoury and green peas; outport life; dances; and building boats
Disorder in Extra-Large Pore Zeolite ITQ-33 Revealed by Single Crystal XRD
No full textThe single crystal of the extra-large pore zeolite, ITQ-33, was obtained and used to explore its crystal structure details. The ITQ-33 structure was found to be disordered with the columnar periodic building unit, explaining the morphology changes upon the different Si/Ge ratio, and the formation of the hierarchical structure from assembling of ITQ-33 nanofibers.Chemistry, MultidisciplinaryCrystallographyMaterials Science, MultidisciplinarySCI(E)EI0ARTICLE104168-41711
Hanging the harp on the willow tree: music and national identity in postcolonial Ireland
No full textAn inquiry into how music served as a nation building tool in the early decades of the Irish Free State.M.A.Includes bibliographical referencesby Crystal N. Galyea
Photonic crystal waveguides in chalcogenide glasses
No full textThe growing speed and bandwidth requirements of telecommunication systems
demand all-optical on-chip solutions. Microphotonic devices can deliver
low power nonlinear signal processing solutions. This thesis looks at the slow
light photonic crystals in chalcogenide glasses to enhance low power nonlinear
operation.
I demonstrate the development of new fabrication techniques for this delicate
class of materials. Both, reactive ion etching and chemically assisted ion
beam etching are investigated for high quality photonic crystal fabrication.
A new resist-removal technique was developed for the chemical, mechanical
and light sensitive thin films.
I have developed a membraning method based on vapor phase etching
in combination with the development of a save and economical etching tool
that can be used for a variety of vapour phase processes.
Dispersion engineered slow light photonic crystals in Ge₃₃As₁₂Se₅₅ are designed
and fabricated. The demonstration of low losses down to 21±8dB/cm
is a prerequisite for the successful demonstration of dispersion engineered
slow light waveguides up to a group index of around n[subscript(g)] ≈ 40.
The slow light waveguides are used to demonstrate highly efficient third
harmonic generation and the first advantages of a pure chalcogenide system
over the commonly used silicon. Ge₁₁.₅As₂₄24Se₆₄.₅ is used for the fabrication
of photonic crystal cavities. Quality factors of up to 13000 are demonstrated.
The low nonlinear losses have enabled the demonstration of second and third
harmonic generation in those cavities with powers up to twice as high as
possible in silicon.
A computationally efficient model for designing coupled resonator bandpass
filters is used to design bandpass filters. Single ring resonators are
fabricated using a novel method to define the circular shape of the rings to
improve the fabrication quality. The spectral responses of the ring resonators
are used to determine the coupling coefficient needed for the design and fabrication
of the bandpass filters. A flat top bandpass filter is fabricated and
characterized as demonstration of this method.
A passive all-optical regenerator is proposed, by integrating a slow-light
photonic crystal waveguide with a band-pass filter based on coupled ring
resonators. A route of designing the regenerator is proposed by first using
the dispersion engineering results for nonlinear pulse propagation and then
using the filter responses to calculate the nonlinear transfer function
Investigation of nucleation and crystal growth kinetics of nickel manganese oxalates
No full textThe nucleation and the crystal growth rates of mixed nickel manganese oxalates have been determined from the changes of the ionic concentration of the solution and the crystal size distribution during the precipitation process within a supersaturation range 0–0.1 M. Thermodynamic solubility calculations have been used to identify the different species contributing the precipitation reaction and for estimation of the thermodynamic constant. Experimental data show that the nucleation rate of mixed nickel manganese oxalate in this supersaturation range is consistent with a primary heterogeneous mechanism and was found to obey to an exponential law. The crystal growth rates indicate a surface-integration-controlled mechanism with a first-order law with respect to the supersaturation
Finite element method for 3D optical modeling of liquid crystal on silicon spatial light modulator
No full textAccurate optical modeling for design and optimization of liquid crystal on silicon spatial light modulators (LCoS SLMs) is important for phase-related applications. Traditional matrix method cannot accurately predict the optical performance when the LC distribution is complex, therefore the rigorous finite element method (FEM) is preferred. However, the optical modeling of LCoS is a multidimensional problem, which is difficult to simulate with FEM. Here, we present the development of an improved FEM by combining the scattering matrix method with the domain decomposition method to reduce the computational burden for optical simulation of LCoS. Furthermore, a 2D simulation example with phase grating displayed on LCoS is presented and compared with experiment.Grant ID: ColoOpt- EU H2020 ITN 721465ImPhys/Optic
Gel-mediated chemo-mechanical control of calcium carbonate crystal formation
No full textThe production of synthetic crystals with controlled shapes and properties is an enticing prospect, yet, the production of such materials is an ongoing challenge. Here, we present a strategy for chemo-mechanically directing the growth of crystals with non-equilibrium structures using a custom-designed double-diffusion cell. We combine chemical additives (e.g., Mg2+ ions) and mechanical confinement (e.g., hydrogel networks) to modulate the growth of calcium carbonate crystals. Specifically, the combination of Mg2+ ions with a strong agarose gel results in calcitic structures, at the gel-glass slide interface, with distinct fried egg-like morphologies and radial or Maltese-cross extinction patterns. In contrast, precipitation with only Mg2+ or agarose results in aragonite spherulites or squished calcite rhombohedra, respectively. Raman spectroscopy and energy dispersive spectroscopy of the “fried eggs” reveals that they are composed of Mg-calcite, which becomes less disordered over time, and the “egg whites” make this transition before the “yolks”. We propose that the “fried eggs” form due to a spherulitic growth process molded by the crystallization-induced delamination of the gel away from the glass slide at the gel-glass interface. In support of the importance of the gel-glass interface, the “fried eggs” do not form when the glass slide is treated with a hydrophobic silane, suppressing heterogeneous nucleation and weakening the interfacial adhesion between the gel and glass, making it easier for the gel to delaminate, thus reducing the confinement effect. As such, this work highlights the important chemo-mechanical role that gel environments can play in crystal formation.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Environmen
Crystal Kuykendall - 04/17/2006 - (Riall Lecture Series)
No full textBegun in 1988, the E. Pauline Riall Lecture Series brings to the University and community outstanding national lecturers in the field of education. The series was established by the late Miss Riall, long-time principal and teacher of the former Salisbury University's Campus School. A generous bequest was provided by Miss Riall's will to fund this special program.
Crystal Arlene Kuykendall, Author and Educational Consultant – Riall Speaker on 4/17/2006 (pm) and 4/18/2006 (am).https://www.youtube.com/watch?v=vFmq73VLgZ
Single photon source using chiral nematic liquid crystal
No full textWith the development of Linear Optics Quantum Computing, a demand for a good single photon source has increased. Here we describe how a cholesteric liquid crystal can be used as a photonic band-gap material to design a single-photon source.We have a dipole embedded in a liquid crystal for which we find the spontaneous emission rate. We calculate the band structureof the cholesteric liquid crystal using the eigenfuncton expansion method and ultimately compute the density of modes. We also determine the field of the dipole embedded inside the cholesteric liquid crystal using the Green's function method from which we determine the spontaneous emmission rate
The self-seeded growth of InAsSb nanowires on silicon by metal-organic vapor phase epitaxy
No full textWe present a study on the growth of InAs1-xSbx alloy nanowires directly on Si (111) substrates via a self seeded mechanism for the first time. Through varying group V flow rate ratios, InAs1-xSbx nanowires with x = from 0 to 0.43 are obtained. It is found that Sb content has a significant effect on the morphology and crystal quality of the formed InAs1-xSbx nanowires. Furthermore, the axial and radial growth rates of the nanowires change in opposite trends with increasing group V flow rate ratio. This indicates that the growth rate of InAs1-xSbx nanowires is ultimately determined by Sb compositions of the nanowires. In addition, the scanning electron microscopy and transmission electron microscopy measurements reveal that the dimensional uniformity and crystal quality of lnAsSb nanovvires with a small amount of Sb compositions are greatly improved compared to the reference lnAs nanovvires. The effect mechanism of Sb on the growth of InAs1-xSbx nanovvires is clarified, which will be a guide for making high quality IRAs' Sb, nanovvires and relevant helerosiruclure devices in the future. (C) 2014 Elsevier B.V. All rights reserved,http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000335905400005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701CrystallographyMaterials Science, MultidisciplinaryPhysics, AppliedSCI(E)[email protected]
- …
