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Full-Text Articles in Physical Sciences and Mathematics
Spectroscopic Studies Of Melamine At High Pressure, Martin Donald Galley
Spectroscopic Studies Of Melamine At High Pressure, Martin Donald Galley
UNLV Theses, Dissertations, Professional Papers, and Capstones
We have performed mid- and far- Infra Red (IR) absorption, Raman spectroscopy, and angular dispersive x-ray diffraction (XRD) studies on melamine under high pressure and room temperature. We have verified the presence of two prior reported phase transitions, the first between 1-2 GPa, and the second between 7-9 GPa. We have also found evidence of a third unreported phase transition between 14-16 GPa, during which, there was a sudden disappearance of all low energy peaks (-1 ) in both the Raman and IR spectra. The far-IR peak movement experiences a discontinuity as the rate of peak movement suddenly changes. …
Raman Spectroscopic Study Of Solid Solution Spinel Oxides, Brian D. Hosterman
Raman Spectroscopic Study Of Solid Solution Spinel Oxides, Brian D. Hosterman
UNLV Theses, Dissertations, Professional Papers, and Capstones
Solid solution spinel oxides of composition MgxNi1−xCr2O4, NiFexCr2−xO4, and FexCr3−xO4 were synthesized and characterized using x-ray diffraction and Raman spectroscopy. Frequencies of the Raman-active modes are tracked as the metal cations within the spinel lattice are exchanged. This gives information about the dependence of the lattice vibrations on the tetrahedral and octahedral cations. The highest-frequency Raman-active mode, A1g, is unaffected by substitution of the divalent tetrahedral cation, whereas the lower frequency vibrations are more strongly affected by substitution of the tetrahedral cation. The change in wavenumber of many phonons is nonlinear upon cation exchange. All detected modes of MgxNi1−xCr2O4 and …
Application Of Raman Spectroscopy In Pharmaceuticals, Anna Zarow
Application Of Raman Spectroscopy In Pharmaceuticals, Anna Zarow
Dissertations
Experimental research on the use of Raman spectroscopy as an in- and on-line sensing tool and a complementary characterization technique for pharmaceutical applications is presented in this thesis. In the first chapter following a broad overview, the use of Raman spectroscopy, together with x-ray powder diffraction, scanning electron microscopy (SEM) and differential scanning calorimetry, for multilevel characterization of cryomilled powders, and the melt-grown amorphous phase of griseofulvin, a model active pharmaceutical ingredient (API), is presented and discussed in detail. A key feature was the observation of a broad inelastic background superimposed on the Raman spectra of cryomilled powders, which is …
Advanced Statistical Methods For Biochemical And Forensic Applications Of Raman Spectroscopy, Vitali Sikirzhytski
Advanced Statistical Methods For Biochemical And Forensic Applications Of Raman Spectroscopy, Vitali Sikirzhytski
Legacy Theses & Dissertations (2009 - 2024)
This work is dedicated to the development and application of advanced statistical methods for biochemical and forensic applications of Raman spectroscopy. We developed a new concept of multidimensional Raman signatures for forensic identification of body fluid traces, which was successfully applied to the study of dried blood, semen, saliva, sweat and vaginal fluid stains. Several alternative advanced chemometric techniques were also successfully tested for the problems of pure body fluids discrimination and mixture analysis. Studies of body fluid mixtures with low blood and semen concentrations indicated that the detection limit of a minor contributor was as low as a few …