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Fundamental and methodological investigations for the improvement of elemental analysis by inductively coupled plasma mass soectrometry

Description: This dissertation describes a variety of studies meant to improve the analytical performance of inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA) ICP-MS. The emission behavior of individual droplets and LA generated particles in an ICP is studied using a high-speed, high frame rate digital camera. Phenomena are observed during the ablation of silicate glass that would cause elemental fractionation during analysis by ICP-MS. Preliminary work for ICP torch developments… more
Date: July 27, 2012
Creator: Ebert, Christopher Hysjulien
Partner: UNT Libraries Government Documents Department
open access

The low temperature properties of (Dy{sub 1-x}Er{sub x})Ni{sub 2} alloys

Description: The study of rare earth magnetic properties is undertaken to further the understanding of critical phenomena and the mechanism of magnetic ordering in solids. There is a great variety of magnetic ordering observed in the rare earth compounds, thus providing an insight to phenomena such as heat capacity, magnetostriction and crystal fields. Studies began on the magnetic properties of the rare earths and their compounds in the 1950`s.
Date: July 27, 1994
Creator: Gailloux, M.
Partner: UNT Libraries Government Documents Department
open access

Directional solidification of the alumina-zirconia ceramic eutectic system

Description: It is possible to produce alumina-zirconia ceramic samples through existing solidification techniques. The resulting microstructures typically consist of rods of zirconia in an alumina matrix, although a lamellar structure has been noted in some cases. In nearly all cases, colony growth was present which may possibly result from grain size, repeated nucleation events, and lamellar oscillations. In the same vein, it appears that the amount of impurities within the system might be the underlying … more
Date: July 27, 1994
Creator: Boldt, C.
Partner: UNT Libraries Government Documents Department
open access

Novel absorption detection techniques for capillary electrophoresis

Description: Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the {mu}M level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling o… more
Date: July 27, 1994
Creator: Xue, Y.
Partner: UNT Libraries Government Documents Department
open access

Development of novel separation techniques for biological samples in capillary electrophoresis

Description: This dissertation includes three different topics: general introduction of capillary electrophoresis (CE); gradient in CE and CE in biological separations; and capillary gel electrophoresis (CGE) for DNA separation. Factors such as temperature, viscosity, pH, and the surface of capillary walls affecting the separation performance are demonstrated. A pH gradient between 3.0 and 5.2 is useful to improve the resolution among eight different organic acids. A flow gradient due to the change in the c… more
Date: July 27, 1994
Creator: Chang, H. T.
Partner: UNT Libraries Government Documents Department
open access

Theoretical study of the noble metals on semiconductor surfaces and Ti-base shape memory alloys

Description: The electronic and structural properties of the ({radical}3 {times} {radical}3) R30{degrees} Ag/Si(111) and ({radical}3 {times} {radical}3) R30{degrees} Au/Si(111) surfaces are investigated using first principles total energy calculations. We have tested almost all experimentally proposed structural models for both surfaces and found the energetically most favorable model for each of them. The lowest energy model structure of the ({radical}3 {times} {radical}3) R30{degrees} Ag/Si(111) surface c… more
Date: July 27, 1994
Creator: Ding, Yungui
Partner: UNT Libraries Government Documents Department
open access

Selenophene transition metal complexes

Description: This research shows that selenophene transition metal complexes have a chemistry that is similar to their thiophene analogs. Selenophene coordination has been demonstrated and confirmed by molecular structure in both the {eta}{sup 5}- and the {eta}{sup 1}(Se)-coordination modes. The reaction chemistry of selenophene complexes closely resembles that of the analogous thiophene complexes. One major difference, however, is that selenophene is a better donor ligand than thiophene making the selenoph… more
Date: July 27, 1994
Creator: White, C. J.
Partner: UNT Libraries Government Documents Department
open access

Quantum dynamical phenomena of independent electrons in semiconductor superlattices subject to a uniform electric field

Description: This report discusses the following topics: Bloch oscillations and other dynamical phenomena of electrons in semiconductor superlattices; solvable dynamical model of an electron in a one-dimensional aperiodic lattice subject to a uniform electric field; and quantum dynamical phenomena of electrons in aperiodic semiconductor superlattices.
Date: July 27, 1994
Creator: Bouchard, A. M.
Partner: UNT Libraries Government Documents Department
open access

Studies of selenium and xenon in inductively coupled plasma mass spectrometry

Description: Since its development, inductively coupled plasma mass spectrometry (ICP-MS) has been a widely used analytical technique. ICP-MS offers low detection limits, easy determination of isotope ratios, and simple mass spectra from analyte elements. ICP-MS has been successfully employed for many applications including geological, environmental, biological, metallurgical, food, medical, and industrial. One specific application important to many areas of study involves elemental speciation by using ICP-… more
Date: July 27, 1994
Creator: Bricker, T.
Partner: UNT Libraries Government Documents Department
open access

Distribution-independent hierarchicald N-body methods

Description: The N-body problem is to simulate the motion of N particles under the influence of mutual force fields based on an inverse square law. The problem has applications in several domains including astrophysics, molecular dynamics, fluid dynamics, radiosity methods in computer graphics and numerical complex analysis. Research efforts have focused on reducing the O(N{sup 2}) time per iteration required by the naive algorithm of computing each pairwise interaction. Widely respected among these are the… more
Date: July 27, 1994
Creator: Aluru, S.
Partner: UNT Libraries Government Documents Department
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