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Full-Text Articles in Physical Sciences and Mathematics

Extreme Ultraviolet Polarimetry With Laser-Generated High-Order Harmonics: Characterization Of Uranium, Nicole Brimhall Jul 2009

Extreme Ultraviolet Polarimetry With Laser-Generated High-Order Harmonics: Characterization Of Uranium, Nicole Brimhall

Theses and Dissertations

We developed an extreme ultraviolet (EUV) polarimeter, which employs laser-generated high-order harmonics as the light source. This relatively high-flux, directional EUV source has available wavelengths between 10 nm and 47 nm with easily rotatable linear polarization. The polarimeter has allowed us to characterize the optical constants of materials that may be useful for EUV optics. The instrument has a versatile positioning system and a spectral resolution of about 180, and we have demonstrated that reflectance as low as 0.1% can be measured repeatably at EUV wavelengths. We investigate the high harmonic source used for polarimetry measurements by documenting the spatial …


Recovery Of Fathead Minnows (Pimephales Promelas) Following Episodic Copper Exposure: A Biochemical, Physiological, Individual, And Population Perspective, Holly Zahner May 2009

Recovery Of Fathead Minnows (Pimephales Promelas) Following Episodic Copper Exposure: A Biochemical, Physiological, Individual, And Population Perspective, Holly Zahner

All Dissertations

The US EPA utilizes the Biotic Ligand Model (BLM) when developing site-specific water-quality criteria for copper. The BLM was calibrated using toxicity data from fixed duration continuous exposures (48 or 96h LC50). However, exposures of copper in natural aquatic systems typically vary in concentration, duration, and may occur multiple times over the life-span of an organism. Additionally, organisms will experience periods in copper free water, potentially allowing them to detoxify and recover homeostasis. Yet, the BLM framework does not consider brief exposures (<24h), multiple exposures, latent responses, or organism recovery, potentially resulting in an inaccurate assessment of exposure toxicity. A recently proposed physiologically-based addition to the BLM will extend the applicability of the framework to brief, multiple pulse copper exposures. Thus, the overall goal of this research was to characterize the recovery of larval Pimephales promelas following episodic copper exposure at a biochemical, physiological, individual, and population level.
The response of whole-body sodium, whole-body Na+/K+-ATPase, and whole-body carbonic anhydrase in larval P. promleas was quantified …


Beta-Diketone And -Ketoenamine-Based Organic Building Blocks For Porous Metal Organic-Materials, Yoseph Solomon Marcos Jan 2009

Beta-Diketone And -Ketoenamine-Based Organic Building Blocks For Porous Metal Organic-Materials, Yoseph Solomon Marcos

LSU Doctoral Dissertations

This dissertation focuses on synthesis of multifunctional â-diketone and â-ketoenamine ligands and their reaction with metal ions, mainly Cu2+. Several new bi-, tri-, and tetrafunctional organosilicon â-diketone building blocks with â-diketone groups at approx. 109° (tetrahedral) were successfully synthesized. New thiophene based bifunctional ligands where the â-diketones are at about 145° are also reported here. We also prepared a range of new aryl-â-ketoenamines from their analogous â-diketones in very high yield using a simple microwave-assisted procedure. Reactions of organosilicon tris(â-diketone)s LH3 with Cu2+ were explored quite intensively. These ligands form metal-organic-polyhedra (MOPs) that are soluble in organic solvents, and insoluble …