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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Self-referencing and Sensitivity Optimization in Photonic Crystal Slabs for Biosensing Applications

Schilling, Ryan 17 July 2013 (has links)
Photonic crystal slabs (PCS) are explored in the context of optofluidic refractive index (RI) sensing for portable, label-free, biosensing applications. The accuracy of RI sensors is limited by noise signals that cause a change in RI that cannot be differentiated from the signal of interest. For this reason self-referencing schemes that provide rejection of common mode signals, and an inherent temperature stabilization approach, are explored. A novel referencing method that allows for frequency shifts to be read out in the transmission power spectrum is proposed and characterized. In terms of improving sensing metrics the relevant characteristics of various PCS architectures are explored numerically. In addition, a novel suspended \emph{air-substrate} device that offers greatly improved sensitivity is proposed and characterized. An experimental measurement near the theoretical detection limit for a PCS is demonstrated. In understanding measurement errors the crossed-polarization effect and its practical limitations are explored numerically.
192

Synthesis and Liquid Crystal Phase Transitions of Zirconium Phosphate Disks

Shuai, Min 03 October 2013 (has links)
Solvent-mediated self-assembly of nanoparticles is an effective and efficient way for the bottom-up organization of functional structures. The primary object of this work is to build up a model system for the study of suspensions of disk-shaped nanoparticles, and use it for the study of self-assembly and discotic liquid crystal phase transitions of discotic particles. The work was introduced by the control over the size and polydispersity of zirconium phosphate (ZrP) disks through synthesis. Systematic experiments revealed that regular-shaped α-zirconium phosphate crystalline disks with a size-to-thickness ratio from 1 to 50 and size polydispersity as low as 0.2 can be obtained through hydrothermal treatment in 3 M to 15 M phosphoric acid solutions. Transmission and scanning electron micrographs revealed that the growth of the disks is mediated by oriented attachment, which happened continuously throughout the hydrothermal treatment between various sized disks. Ostwald ripening is effective in improving the regularity of the shape of the disks, especially under prolonged hydrothermal treatment. Under the microwave assisted hydrothermal conditions, the rate of attachment on the flat surfaces of the disks is accelerated, which leads to the formation of the column-shaped crystals. With the ability to adjust the size, aspect ratio, and polydispersity of ZrP disks, the study on self-assembly behavior and the discotic liquid crystal phases was enabled. Firstly, liquid crystal phases of aqueous suspensions of ZrP disks were investigated. Iridescent smectic phase and the critical points of phase transitions were found. Moreover, monolayer ZrP nanosheets with extremely high aspect ratio, which were achieved by exfoliating the ZrP crystals, were also used in this study. The high aspect ratio of nanosheets produces a laminar phase at low nanosheet concentration. Chiral liquid crystal phases were demonstrated when increased the concentration of the nanosheets. The competition between the chirality and layering leads to twisted and layered structures. For the final part, solvent-mediated self-assembly of disks and nanosheets via undulation of liquid crystal phases showed an interesting approach for bottom-up design of functional nano-structures.
193

Systematic approach to protein crystallization :emphasis on Vaccinia virus complement control protein (VCP).

Adusei-Danso, Felix January 2006 (has links)
<p>This work examined the systematic approach to protein crystallization, exploring some of the techniques that have been developed to enhance the success rate of crystallization. The work was centered on two proteins / namely Vaccinia virus complement control protein (VCP) and glutamate dehydrogenase (GDH) from Bacteriodes fragilis. The crystal structures of the full lengthe native VCP and VCP bound to heparin had already been determined. In the same way, the structure of GDH from Bacteriodes fragilis is not known, even though structures of other GDHs from different organisms have been determined.</p>
194

Reconfigurable Photonic Crystal Cavities

Smith, Cameron January 2009 (has links)
Doctor of Philosophy (PhD) / Photonic crystals are optical structures that contain a periodic modulation of their refractive index, allowing them to control light in recent years of an unprecedented capacity. Photonic crystals may take on a variety of configurations, in particular the photonic crystal cavity, which may “hold” light in small volumes comparable to the light’s wavelength. This capability to spatially confine light opens up countless possibilities to explore for research in telecommunications, quantum electrodynamics experiments and high-resolution sensor applications. However, the vast functionality potentially made available by photonic crystal cavities is limited due to the difficulty in redefining photonic crystal components once they are formed in their (typically) solid material. The work presented in this thesis investigates several approaches to overcome this issue by reconfiguring photonic crystal cavities.
195

The transmission characteristics of some optical crystals in the extreme ultraviolet /

McClinton, Arthur Thomas, January 1966 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute, 1966. / Vita. Abstract. Includes bibliographical references (leaves 38-39). Also available via the Internet.
196

Nucleation and growth of crystals of pharmaceuticals on functionalized surfaces

Biyikli, Kasim. January 2006 (has links)
Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: crystal growth; monolayer; polymorph. Includes bibliographical references (leaves 106-120).
197

The effect of surface modification on the crystal growth of iron oxides /

Barton, Thomas F., January 1990 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 154-158). Also available via the Internet.
198

Design and fabrication of photonic crystal fibers for nonlinear microscopy /

Zheng, Juanjuan. January 2008 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 82-93). Also available in electronic version.
199

New type transflective liquid crystal displays /

Mak, Hin Yu. January 2008 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references. Also available in electronic version.
200

Theory of resonance and mode coupling in photonic crystal devices

White, Thomas P. January 2005 (has links)
Thesis (Ph. D.)--University of Sydney, 2006. / Title from title screen (viewed 30 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Physics, Faculty of Science. "Centre for Ultrahigh-bandwidth Devices for Optical Systems" -- T.p. Degree awarded 2006; thesis submitted 2005. Includes bibliographical references. Also available in print form.

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