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High Resolution Studies of the Origins of Polyatomic Ions in Inductively Coupled Plasma-Mass Spectrometry

Description: The inductively coupled plasma (ICP) is an atmospheric pressure ionization source. Traditionally, the plasma is sampled via a sampler cone. A supersonic jet develops behind the sampler, and this region is pumped down to a pressure of approximately one Torr. A skimmer cone is located inside this zone of silence to transmit ions into the mass spectrometer. The position of the sampler and skimmer cones relative to the initial radiation and normal analytical zones of the plasma is key to optimizing… more
Date: August 9, 2006
Creator: Ferguson, Jill Wisnewski
Partner: UNT Libraries Government Documents Department
open access

Designing of Metallic Photonic Structures and Applications

Description: In this thesis our main interest has been to investigate metallic photonic crystal and its applications. We explained how to solve a periodic photonic structure with transfer matrix method and when and how to use modal expansion method. Two different coating methods were introduced, modifying a photonic structure's intrinsic optical properties and rigorous calculation results are presented. Two applications of metallic photonic structures are introduced. For thermal emitter, we showed how to de… more
Date: August 9, 2006
Creator: Kim, Yong-Sung
Partner: UNT Libraries Government Documents Department
open access

Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors

Description: Fluidized beds (FB) reactors are widely used in the polymerization industry due to their superior heat- and mass-transfer characteristics. Nevertheless, problems associated with local overheating of polymer particles and excessive agglomeration leading to FB reactors defluidization still persist and limit the range of operating temperatures that can be safely achieved in plant-scale reactors. Many people have been worked on the modeling of FB polymerization reactors, and quite a few models are … more
Date: August 9, 2006
Creator: Fan, Rong
Partner: UNT Libraries Government Documents Department
open access

Biomimetic Nanocomposites of Calcium Phosphate and Self-Assembling Triblock and Pentablock Copolymers

Description: In an effort to mimic the growth of natural bone, self-assembling, micelle and gel-forming copolymers were used as a template for calcium phosphate precipitation. Because of the cationic characteristics imparted by PDEAEM end group additions to commercially available Pluronic{reg_sign} Fl27, a direct ionic attraction mechanism was utilized and a polymer-brushite nanocomposite spheres were produced. Brushite coated spherical micelles with diameters of {approx}40 nm, and agglomerates of these par… more
Date: August 9, 2006
Creator: Enlow, Drew Lenzen
Partner: UNT Libraries Government Documents Department
open access

Surface-Enhanced Raman Scattering (SERS) for Detection in Immunoassays: applications, fundamentals, and optimization

Description: Immunoassays have been utilized for the detection of biological analytes for several decades. Many formats and detection strategies have been explored, each having unique advantages and disadvantages. More recently, surface-enhanced Raman scattering (SERS) has been introduced as a readout method for immunoassays, and has shown great potential to meet many key analytical figures of merit. This technology is in its infancy and this dissertation explores the diversity of this method as well as the… more
Date: August 9, 2006
Creator: Driskell, Jeremy Daniel
Partner: UNT Libraries Government Documents Department
open access

Transient Eddy Current Response Due to a Subsurface Crack in a Conductive Plate

Description: Eddy current nondestructive evaluation (NDE) is usually carried out by exciting a time harmonic field using an inductive probe. However, a viable alternative is to use transient eddy current NDE in which a current pulse in a driver coil produces a transient .eld in a conductor that decays at a rate dependent on the conductivity and the permeability of the material and the coil configuration. By using transient eddy current, it is possible to estimate the properties of the conductive medium and … more
Date: August 9, 2006
Creator: Fu, Fangwei
Partner: UNT Libraries Government Documents Department
open access

The Node Monitoring Component of a Scalable Systems Software Environment

Description: This research describes Fountain, a suite of programs used to monitor the resources of a cluster. A cluster is a collection of individual computers that are connected via a high speed communication network. They are traditionally used by users who desire more resources, such as processing power and memory, than any single computer can provide. A common drawback to effectively utilizing such a large-scale system is the management infrastructure, which often does not often scale well as the syste… more
Date: August 9, 2006
Creator: Miller, Samuel James
Partner: UNT Libraries Government Documents Department
open access

Structurally Integrated Photoluminescence-Based Lactate Sensor Using Organic Light Emitting Devices (OLEDs) as the Light Source

Description: Multianalyte bio(chemical) sensors are extensively researched for monitoring analytes in complex systems, such as blood serum. As a step towards developing such multianalyte sensors, we studied a novel, structurally integrated, organic light emitting device (OLED)-based sensing platform for detection of lactate. Lactate biosensors have attracted numerous research efforts, due to their wide applications in clinical diagnosis, athletic training and food industry. The OLED-based sensor is based on… more
Date: August 9, 2006
Creator: Qian, Chengliang
Partner: UNT Libraries Government Documents Department
open access

Soft-Lithographical Fabrication of Three-dimensional Photonic Crystals in the Optical Regime

Description: This dissertation describes several projects to realize low-cost and high-quality three-dimensional (3D) microfabrication using non-photolithographic techniques for layer-by-layer photonic crystals. Low-cost, efficient 3D microfabrication is a demanding technique not only for 3D photonic crystals but also for all other scientific areas, since it may create new functionalities beyond the limit of planar structures. However, a novel 3D microfabrication technique for photonic crystals implies the … more
Date: August 9, 2006
Creator: Lee, Jae-Hwang
Partner: UNT Libraries Government Documents Department
open access

Quantum Monte Carlo Calculations Applied to Magnetic Molecules

Description: We have calculated the equilibrium thermodynamic properties of Heisenberg spin systems using a quantum Monte Carlo (QMC) method. We have used some of these systems as models to describe recently synthesized magnetic molecules, and-upon comparing the results of these calculations with experimental data-have obtained accurate estimates for the basic parameters of these models. We have also performed calculations for other systems that are of more general interest, being relevant both for existing… more
Date: August 9, 2006
Creator: Engelhardt, Larry
Partner: UNT Libraries Government Documents Department
open access

Couples Magnetic and Structural Transitions in High-Purity Dy and Gd5SbxGe4-x

Description: Magnetic materials exhibiting magnetic phase transitions simultaneously with structural rearrangements of their crystal lattices hold a promise for numerous applications including magnetic refrigeration, magnetomechanical devices and sensors. We undertook a detailed study of a single crystal of dysprosium metal, which is a classical example of a system where magnetic and crystallographic sublattices can be either coupled or decoupled from one another. Magnetocaloric effect, magnetization, ac ma… more
Date: August 9, 2006
Creator: Chernyshov, Alexander S.
Partner: UNT Libraries Government Documents Department
open access

Resorption Rate Tunable Bioceramic: Si, Zn-Modified Tricalcium Phosphate

Description: This dissertation is organized in an alternate format. Several manuscripts which have already been published or are to be submitted for publication have been included as separate chapters. Chapter 1 is a general introduction which describes the dissertation organization and introduces the human bone and ceramic materials as bone substitute. Chapter 2 is the background and literature review on dissolution behavior of calcium phosphate, and discussion of motivation for this research. Chapter 3 is… more
Date: August 9, 2006
Creator: Wei, Xiang
Partner: UNT Libraries Government Documents Department
open access

Automated High Throughput Protein Crystallization Screening at Nanoliter Scale and Protein Structural Study on Lactate Dehydrogenase

Description: The purposes of our research were: (1) To develop an economical, easy to use, automated, high throughput system for large scale protein crystallization screening. (2) To develop a new protein crystallization method with high screening efficiency, low protein consumption and complete compatibility with high throughput screening system. (3) To determine the structure of lactate dehydrogenase complexed with NADH by x-ray protein crystallography to study its inherent structural properties. Firstly,… more
Date: August 9, 2006
Creator: Li, Fenglei
Partner: UNT Libraries Government Documents Department
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