Physical Sciences and Mathematics Commons^™

Studies Of Microscopic Scale Strains In Nickel Alloys Resulting From Mechanical And Chemical Forces, Jing Chao

Electronic Thesis and Dissertation Repository

The nickel-based Alloy 600, also known as Inconel 600 has been found to be susceptible to stress corrosion cracking (SCC) in high temperature aqueous environments. Despite extensive research, the mechanisms by which this process occurs remain in question. It is known that SCC results from the simultaneous effects of a chemically corrosive environment and a tensile stress. Many studies have been conducted on the microscopic chemical changes associated with SCC. There have been fewer studies of the microscopic stress/strain process. The main objective of this thesis is to use the new x-ray based diffraction technique – polychromatic x-ray microdiffraction (PXM) …

Fundamental Studies And Bioanalytical Applications Of Nanostructured-Initiator Mass Spectrometry (Nims), Jin Li

Electronic Thesis and Dissertation Repository

Nanostructured-Initiator Mass Spectrometry (NIMS), which uses ‘initiator’ molecules trapped within a nanostructured material to assist the release and ionization of intact molecules adsorbed on that material's surface upon laser or ion irradiation, is a new soft desorption/ ionization technique with several positive attributes including extraordinarily high detection sensitivities, relatively simple sample preparation protocols, and can be initiated using photon or ion irradiation sources. As result NIMS has a great deal of potential for the ready detection of small molecules from complex biofluids including metabolites, and for tissue imaging.

In the thesis, a variety of nanostructured materials including porous silicon (pSi), …

Investigations Of Zeolite Growth By Atomic Force Microscopy (Afm), Donghan Chen

Electronic Thesis and Dissertation Repository

Zeolites are microporous materials that have been used extensively in various fields. A better understanding on their crystallization process is important for their investigations. Atomic force microscopy (AFM) is a powerful tool for studying the growing traces on the crystal surface, providing information regarding the relation between surface events and framework structure. This thesis mainly focuses on the surface investigation of several zeolites and microporous materials. ZSM-11 single crystals were synthesized under hydrothermal conditions, and their crystallization process was monitored by AFM, PXRD, SEM, and SSNMR. SAPO-34 prepared under both HTS and DGC conditions showed morphological differences that are related …

X-Ray Absorption Fine Structure And X-Ray Excited Optical Luminescence Studies Of One-Dimensional Nanomaterials, Lijia Liu

Electronic Thesis and Dissertation Repository

One dimensional nanomaterials have attracted extensive attention in recent years due to their superior electrical, optical, mechanical and chemical properties compared to their bulk counterparts. In this thesis, electronic structure and optical properties of three types of nanomaterials are investigated using synchrotron based X-ray absorption spectroscopy: X-ray absorption fine structure (XAFS) and X-ray excited optical luminescence (XEOL).

Si nanowire arrays are synthesized using electroless chemical etching, and coated with platinum and gold nanoparticles. The interaction between metal nanoparticles and the nanowire substrate is investigated using X-ray absorption near-edge structure (XANES). The luminescence properties of thermally oxidized Si nanostructures, such as …

High-Pressure Study Of Molecular Solids And 1d Nanostructures By Vibrational Spectroscopy And Synchrotron X-Ray Diffraction, Zhaohui Dong

Electronic Thesis and Dissertation Repository

Pressure plays a critical role in regulating the structures and properties of materials. Since Percy Bridgeman was recognized by the 1946 Nobel Prize for his contribution to high-pressure physics, high-pressure research as an interdisciplinary area has attracted extensive attentions. Nowadays, the high-pressure research involves broad frontier areas, such as chemistry, physics, biology, material and earth science. For instance, brand new classes of inorganic materials of unusual stoichiometries and crystal structures, with wide range of optical, mechanical, electronic and magnetic properties, have been produced at high pressure. Pressure-induced structural transformations between crystalline and amorphous materials, as well as among insulators, conductors …

Electrohydrodynamic Enhancement Of Heat Transfer And Mass Transport In Gaseous Media, Bulk Dielectric Liquids And Dielectric Thin Liquid Films, Seyed Reza Mahmoudi

Electronic Thesis and Dissertation Repository

Controlling transport phenomena in liquid and gaseous media through electrostatic forces has brought new important scientific and industrial applications. Although numerous EHD applications have been explored and extensively studied so far, the fast-growing technologies, mainly in the semiconductor industry, introduce new challenges and demands. These challenges require enhancement of heat transfer and mass transport in small scales (sometimes in molecular scales) to remove highly concentrated heat fluxes from reduced size devices. Electric field induced flows, or electrohydrodynamics (EHD), have shown promise in both macro and micro-scale devices.

Several existing problems in EHD heat transfer enhancements were investigated in this thesis. …

Solid-State Nuclear Magnetic Resonance Spectroscopy Of Unreceptive Quadrupolar Nuclei In Inorganic Materials, Andre Sutrisno

Electronic Thesis and Dissertation Repository

Preparation and characterization of inorganic materials is a crucial practice because understanding the relationship between structure and property is important for improving current performance and developing novel materials. Many metal centers in technologically and industrially important materials are unreceptive low-γ quadrupolar nuclei (i.e., possessing low natural abundance, low NMR frequencies and large quadrupole moments) and they usually give rise to very broad NMR resonances and low signal-to-noise ratios, making it difficult to acquire their solid-state NMR spectra. This thesis focuses on the characterization of inorganic materials using solid-state NMR (SSNMR) spectroscopy at very high magnetic field of …

Enhancing Raman And Fluorescence Spectroscopies With Nanosphere Lithography Platforms, Shabila Fayyaz

Electronic Thesis and Dissertation Repository

Localized surface plasmon resonance (LSPR) is of particular interest to enhance the limit of detection for spectroscopic techniques such as Raman and fluorescence via a surface enhancement from metallic nanostructures. In this study, using nanosphere lithography (NSL) technique, a series of gold nanostructures over glass surfaces are prepared. These nanostructures are used to record the surface enhanced Raman scattering (SERS) spectrum of benzenethiol and azobenzene thiol and the vibrational modes are compared to literature. Once protected with an ultrathin layer of SiO₂, the gold nanostructures are investigated using scanning confocal fluorescence microscopy to detect the fluorescence from a …

Scanning Probe Microscopy Studies Of The Properties Of Conducting Polymers, Kevin D. O'Neil

Electronic Thesis and Dissertation Repository

Electronically conducting polymers (ECPs) have been growing in interest as important materials for a variety of different applications such as charge storage devices and photovoltaics. However, in all of these applications, the performance of conducting polymers are strongly dependent upon their local properties such as morphology, local conductivity and carrier mobility, local chemical composition, etc. All polymer materials feature a distribution of these parameters and therefore, they are considered heterogeneous. In this work, we use atomic force microscopy (AFM) and its related techniques such as current-sensing AFM (CS-AFM), Kelvin probe force microscopy (KFM) and phase imaging (PI-AFM) to directly investigate …