Inorganic Chemistry Commons^™

Three Dimensional Positron Annihilation Momentum Measurement Technique (3dpamm) Applied To Measure Oxygen-Atom Defects In 6h Silicon Carbide, Christopher S. Williams

Theses and Dissertations

A three-dimensional Positron Annihilation Spectroscopy System (3DPASS) capable to simultaneously measure three-dimensional electron-positron (e--e+) momentum densities measuring photons derived from e--e+ annihilation events was designed and characterized. 3DPASS simultaneously collects a single data set of correlated energies and positions for two coincident annihilation photons using solid-state double-sided strip detectors (DSSD). Positions of photons were determined using an interpolation method which measures a figure-of-merit proportional to the areas of transient charges induced on both charge collection strips directly adjacent to the charge collection strips interacting with the annihilation photons. The subpixel resolution was measured for both double-sided strip detectors (DSSD) and …

Improved Modeling Of Midlatitude D-Region Ionospheric Absorption Of High Frequency Radio Signals During Solar X-Ray Flares, Evelyn A. Schumer

Theses and Dissertations

The purpose of this research was to improve modeling of midlatitude D-region ionospheric absorption of high frequency radio signals during solar X-ray flares through analysis of HF propagation data obtained during the HF Investigation of D-region Ionospheric Variation Experiment (HIDIVE) and obtained at the Canadian Space Agency NORSTAR riometer in Pinawa, Manitoba, Canada and X-ray flux data, as reported by GOES satellites. The findings of the data analysis were then used to validate and suggest improvements for two existing HF absorption models, the operational Space Weather Prediction Center (SWPC) D-region Absorption model and the physical AbbyNormal model. Analysis of the …

Experimental Validation Techniques For The Heleeos Off-Axis Laser Propagation Model, John D. Haiducek

Theses and Dissertations

The High Energy Laser End-to-End Operational Simulation (HELEEOS) off-axis scattering algorithm is designed to predict the irradiance that will be detected at a given off-axis location due to atmospheric scattering of a high-energy laser. The HELEEOS system models the propagation of the laser through the atmosphere, accounting for such effects as turbulence, thermal blooming, and atmospheric absorption. The HELEEOS off-axis scattering algorithm uses the scattering phase functions of the Mie scattering models to predict the amount of radiation that will be scattered toward a particular observation location from each point along the beam path, and the total irradiance that will …

In-Situ, Gate Bias Dependent Study Of Neutron Irradiation Effects On Algan/Gan Hfets, Janusz K. Mikina

Theses and Dissertations

AlGaN/GaN Heterostructure Field Effect Transistors (HFETs) have come under increased study in recent years due to their highly desirable material and electrical properties and survivability even during and after exposure to extreme temperature and radiation environments. In this study, unpassivated and SiN passivated Al_0.27Ga_0.73N/GaN HFETs were subjected to neutron radiation at 120 K. The primary focus of the research was the effects of neutron irradiation on drain current, gate leakage current, threshold voltage shift, gate-channel capacitance, and the effects of biasing the gate during irradiation. In-situ measurements were conducted on transistor current, gate-channel capacitance, and gate …

Optical Properties Of Si, Ge, Gaas, Gasb, Inas, And Inp At Elevated Temperatures, Thomas R. Harris

Theses and Dissertations

Investigation of the optical and electrical behavior of some semiconductors at very high temperatures has not been an area of much study, at least not experimentally. The importance of such research becomes obvious due to the effects of high temperatures on semiconductor devices such as infrared detectors and light emitters. Besides the destructive effects of thermal stress and melting, changes in the optical properties of the material can greatly affect device performance. In this research, the infrared absorption of Si, Ge, GaAs, GaSb, InAs, and InP was measured from 0.6 to 25 μm at temperatures ranging from 295 up to …

Changes To Electrical Conductivity In Irradiated Carbon-Nickel Nanocomposites, David F. Coy

Theses and Dissertations

Pre and post irradiation resistivity and XAFS measurements have been conducted to examine the effects of 0.5 MeV electron irradiations on nickel-carbon composites. Results showed a decrease in surface resistivity in all sample types of 14-30% following irradiation with a total electron exposure of 4 x 10^-16 cm^-2. Results also showed a corresponding decrease in NiO content for the irradiated samples as compared to measurements of non-irradiated samples. Surface resistivity measurement capabilities were established and measurement techniques refined to produce repeatable results of sufficient precision to discern changes in resistivity for an exposure of 2 x 10 …

The Material Properties Of Cssnbr3 And Csbr:Sn-1% And Their Potential As Scintillator Detector Material, Neal B. Kleinschmidt

Theses and Dissertations

The search for superior nuclear radiation detection materials is ongoing. Current scintillator materials using Thallium doped Sodium Iodide or Cesium Iodide are the benchmarks for ease of use and quick identification of isotope species. This research aims to explore Cesium Bromide doped with 1% molar tin (CsBr:Sn-1%) and Cesium Tin Bromide (CsSnBr₃) as candidate materials for a new scintillator. The techniques of Extended X-Ray Absorption Fine Structure (EXAFS), X-Ray Absorption Near Edge Structure (XANES) and Cathodoluminescence are used to determine the suit- ability of CsSnBr3 and CsBr:Sn-1% with Sn⁴⁺ as a potential scintillator materials and explore their …

Synthesis And Characterization Of Allylic Dinuclear Molybdenum Complexes With Bridging Oxygen And Sulfur Containing Ligands., Mazin Shatnawi, Samer Tanash, Saleem Al-Ahmad, Paul Challen, Gerald Henkel

Paul R. Challen

No abstract provided.

An Examination Of Factors Influencing The Thermodynamics Of Correlation-Gas Chromatography As Applied To Large Molecules And Chiral Separations, Dmitry Lipkind, James S. Chickos

James Chickos

No abstract provided.

Conformations Of A Model Protein Revealed By An Aggregating Cuᴵᴵ Porphyrin: Sensing The Difference, G. De Luca, A. Romeo, L. M. Scolaro, Robert F. Pasternack

Chemistry & Biochemistry Faculty Works

Aggregated t-CuP binds to poly-L-glutamate through supramolecular interactions, revealing itself to be an extremely sensitive probe for the major conformations of the polymeric scaffold.

(2e)-1-(6-Chloro-2-Methyl-4-Phenylquinolin-3-Yl)-3-Phenylprop-2-En-1-One, Tan Kong Wai, Viji A. J., Vijayakumar V., Sarveswari S.

Tan Kong Wai

In the title compound, C(25)H(18)ClNO, the conformation about the C=C double bond is E. Significant twists are evident in the molecule, with the benzene ring forming a dihedral angle of 53.92 (11)degrees with the quinolinyl residue. Further, the chalcone residue is approximately perpendicular to the quinolinyl residue [C(q)-C(q)-C(c)-O(c) torsion angle = -104.5 (3)degrees, where q = quinolinyl and c = chalcone]. In the crystal, the presence of C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions leads to supramolecular layers lying parallel to ((1) over bar 02).

Grafika Inżynierska Ćw., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Projektowanie Procesów Biotechnologicznych Proj., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Projektowanie I Optymalizacja Procesów Proj., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Metody Numeryczne Lab., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Odnawialne Źródła Energii W., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Understanding The Promotion Effect: A Density Functional Theory Study Based On High Resolution Transmission Electron Microscopy Images For Mos2-Cobalt Promoted Interfaces, Manuel A. Ramos

Open Access Theses & Dissertations

Many studies had been done in order to understand promotion effect and structure/function in unsupported catalyst. Results indicated that d-electrons play an important role promoting catalytical active sites at the edges of MoS2 catalytically structures. Sulfur removal from crude oil, occurs on the edge of molybdenum di-sulfide (MoS2) nano structures, due to promotion of MoS2 nano structures with nickel or cobalt in sulfur-terminated or molybdenum-terminated edge planes. The promotion leads to formation of so-called CoMoS phase (MoS2/Co9S8) first discovered by meaning of Mössbauer spectroscopy, much more CoMoS phase usually called unsupported catalytical particles, have been topic of great interest in …

Oxidation Of Dibenzothiophene To Dibenzothiophene Using Metal Nanoparticles Supported On Silica, Karina Castillo

Open Access Theses & Dissertations

Silica and nanoparticles of Pt, Au, and Ag supported on silica were tested for the ability to oxidize dibenzothiophene (DBT) to sulfone. High performance liquid chromatography was used to study the removal of DBT from solution. In addition, X- ray diffraction, infrared spectroscopy and Raman Spectroscopy were used to characterize the product of the oxidation reaction. Further studies involved the use X-ray absorption spectroscopy to characterize the nanoparticle catalysts before and after the oxidation reaction.

To better understand the reaction, silica was synthesized at different pHs using three different acids. The acids used to synthesize the silica were HCl, HNO3, …

Samuel J. Danishetsky And The Synthesis Of Globo-H Antigen, Chelsey Jones

Natural Sciences Student Research Presentations

Samuel J. Danishefsky is a research scientist at the Sloan-Kettering Institute. He uses his knowledge in organic chemistry to make biological advances in cancer research. Danishefsky has been conducting research and experiments on synthesizing anti-cancer vaccines with the use of carbohydrate antigens. Danishefsky has also been conducting research and experiments on homogeneous erythropoietin which could provide insight into how glycoproteins function. Knowledge of glycoprotein would allow scientists to better understand erythropoietin which can treat anemia in chemotherapy patients. All is valuable information in advances in cancer research and cancer research is important because it is a major disease affecting the …

Development Of Metal-Based Luminescent Probes For Applications In Biomolecular Structure And Dynamics, Ayesha Sharmin

Graduate Student Theses, Dissertations, & Professional Papers

New transition-metal complexes containing luminescent properties have been designed and synthesized for application as structural probes for biomolecules. Potential DNA intercalators, 2- amino-anthracene substituted triosmium clusters, were synthesized by the reactions of 2-aminoanthracene with [Os3(CO)10(CH3CN)2]. The products [Os3(CO)10(μ-η2-(N-C(1))-NH2C14H8)(μ- H)], [Os3(CO)10(μ-η2-(N-C(3))-NHC14H9)(μ-H)], [Os3(CO)9(μ-η2-(N-C(3))-NHC14H8)(μ-H)2] and [Os3(CO)9(μ3-η2-(N-C(3))-NHC10H9)(μ-H)] obtained from this reaction have been structurally characterized by spectroscopic, photophysical and electrochemical techniques. Solid state structures are also reported for the complexes [Os3(CO)10(μ-η2-(N-C(3))-NHC14H9)(μ-H)] and [Os3(CO)9(μ-η2-(N-C(3))-NHC14H8)(μ-H)2]. To investigate bio-macromolecular dynamics on the sub-microsecond-to-microsecond timescale, a series of ruthenium based mono-nuclear metalligand charge-transfer complexes (MLCs) of formula [XRu(CO)(L–L)(L′)2][PF6] (X = H, TFA, Cl; L–L = 2,2′-bipyridyl, 1,10-phenanthroline, 5-amino-1,10-phenanthroline …