Physical Sciences and Mathematics Commons^™

Development And Application Of New Solid-State Models For Low-Energy Vibrations, Lattice Defects, Entropies Of Mixing, And Magnetic Properties, Jacob M. Schliesser

Theses and Dissertations

Low-temperature heat capacity data contain information on the physical properties of materials, and new models continue to be developed to aid in the analysis and interpretation of heat capacity data into physically meaningful properties. This work presents the development of two such models and their application to real material systems. Equations describing low-energy vibrational modes with a gap in the density of states (DOS) have been derived and tested on several material systems with known gaps in the DOS, and the origins of such gaps in the DOS are presented. Lattice vacancies have been shown to produce a two-level system …

Surface Modification, Fabrication, And Characterization Of Silicon, Polymer, And Nanotube Composite Materials, Lei Pei

Theses and Dissertations

In my research, I have performed many characterization and fabrication experiments that are based on tools of analytical chemistry, materials chemistry, and surface science. My research projects are as follows. (1) Fabrication of transparent polymer templates for nanostructured amorphous silicon photovoltaics was done using low-cost nanoimprint lithography of polydimethylsiloxane. This approach provides a test bed for absorption studies in nanostructured film geometries and should result in improved light capturing designs in thin-film solar cells. Nanopatterned polymer films were characterized by scanning electron microscopy and optical measurements. (2) A straightforward method for fabricating freely suspended, thin, carbon nanotube (CNT) membranes infiltrated …

Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia

Theses and Dissertations

Nanomaterials display interesting physical and chemical properties depending on their shape, size and composition. Self assembly is an intriguing route to producing nanomaterials with controllable compositions and morphologies. DNA has been used to guide the self assembly of materials, resulting in: (1) metal nanowires; (2) metal or semiconductor nanorods; (3) carbon nanotubes; and (4) semiconductor, metal or biological nanoparticles. My work expands the range of DNA templated nanomaterials and develops novel ways of using DNA to pattern nanostructures on surfaces. I have performed the first synthesis of silver nanorods on single stranded DNA, an attractive material for localizing DNA coupled …

Velocity And Temperature Characterization Of The First Vacuum Stage Expansion In An Inductively Coupled Plasma - Mass Spectrometer, William Neil Radicic

Theses and Dissertations

The inductively coupled plasma - mass spectrometer (ICP-MS) is the analytical instrument of choice for trace element detection and quantification. Despite the popularity of ICP-MS, significant degradation in sensitivity and precision occurs as the result of matrix and instrument-induced effects. The sources of these effects are not well understood, characterized, or correlated to particular plasma operating condition settings or matrix compositions and involve both neutral and charged species. The purpose of this study is to characterize the behavior of metastable Ar (I) atom and Ca (II) ion through the measurement of Doppler velocities and fluorescence line width "temperatures."

For the …