Physical Sciences and Mathematics Commons^™

A Study Of How Precursor Key Concepts For Organic Chemistry Success Are Understood By General Chemistry Students, Patrick Gerard Meyer

Dissertations

This study examines college student understanding of key concepts that will support future organic chemistry success as determined by university instructors. During four one-hour individual interviews the sixteen subjects attempted to solve general chemistry problems. A think-aloud protocol was used along with a whiteboard where the students could draw and illustrate their ideas. The protocols for the interviews were adapted from the Covalent Structure and Bonding two-tiered multiple choice diagnostic instrument (Peterson, Treagust, & Garnett, 1989) and augmented by the Geometry and Polarity of Moleculessingle-tiered multiple choice instrument (Furió & Calatayud, 1996). The interviews were videotaped, transcribed, and coded …

Online Support For Multivariate Integration, Shujun Li

Dissertations

In this dissertation, we present an online problem solving environment for multivariate numerical integration. To build an environment for users with various backgrounds, we address issues of Web interface support for end-users, remote application programming interfaces for distributed system programmers, visualization of multivariate integrand functions for problem analysis, and highly efficient integration methods. Compared to previous implementations, our new load balancing schemes increase the scalability of parallel integration and hence are suitable for large scale computations. A parallel integration service, called PI service, was implemented based on Web services technologies to support both remote integration and remote visualization. The multivariate …

Photoexcitation And Photoionization Of The Argon Atom And The Hydrogen Bromide Molecule, Ximao Feng

Dissertations

Interaction between synchrotron radiation with inner-shell electrons is a fundamental method to study the structure and dynamics of atoms and molecules. This thesis, under the guidance of Dr. Nora Berrah, concentrates on the study of the interaction between soft x-ray photons with Ar atoms and HBr moleculeswith time-of-flight (TOF) electron spectrometers and two-dimensional photoelectron spectroscopy (2DPES). Both of the experiments were performed on theAtomic, Molecular and Optical Physics undulator beamline at the Advanced Light Source at Lawrence Berkeley National Laboratory.

The argon study focused on photoelectron recapture when the 2p electrons are ionized just above the thresholds of the two …

Influence Of Uncorrelated Defects On The Vortex Phase Diagram In Yba2Cu3O7-6 Superconducting System, Lucian M. Undreiu

Dissertations

The goal of our work is to gain more insight into the vortex dynamics in YBa₂Cu₃0_7-8 single crystals with point defects induced by 9MeV proton irradiation. The position of the critical points from the first order melting transition line can be shifted in a controlled manner with the induced disorder. In order to accomplish a comparative study, different crystals and irradiation doses were used. The results were correlated using both electrical transport and ac specific heat measurements. Special attention was given to investigating the nature of the vortex state below the lower critical point o …

Single-Electron Capture Processes In Slow Collisions Of He^2+ Ions With Molecular Targets, Osama Abu-Haija

Dissertations

Translational energy-gain spectroscopy (TES) has been used to investigate state-selective dissociative and non-dissociative single-electron capture processes in low-energy collisions of He²⁺ ions with O₂ , H₂ O, CO₂ , N₂ , and NH3 at impact energies between 100 eV and 1600 eV. The measured energy spectra for theHe²⁺ -O₂ and H₂ O collision systems show that the dominant exit channel is due to dissociative transfer ionization (DTI), single-electron captureaccompanied by ionization of the molecular target-ion, at the lowest collision energies. As the impact energy is increased non-dissociative single-electron capture (SEC) into the …

Synthesis And Spectroscopic Characterization Of Manganese Doped Zinc Sulfide Quantum Dot Nanocrystals, Pedro A. Gonzalez Beerman

Dissertations

Zinc sulphide quantum dots were synthesized in aqueous media using sodium polyphosphate as the stabilizer. The nanoparticles were 2.5 ± 0.5 nm and 5.0 ± 0.5 nm diameter depending on the synthetic procedure employed and the amount of Mn doped varied from 0.003 to 0.32% (w/w). The nanoparticles were characterized by UV-Vis absorption, luminescence, EPR, near edge x-ray absorption fine structure (NEXAFS), and x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD), and transmission electron microscopy (TEM). These quantum dots show a strong emission at 590 nm due to the ⁴T₁ -⁶A₁ transition characteristic of Mn …

Acylpyrazolones: Synthesis, Self-Assembly And Lanthanide Metal Ion Separation, Jun Yang

Dissertations

The central hypothesis that nanoscale self-assemblies can provide excellent metal ion recognition has been substantiated by employing acylpyrazolones and trivalent lanthanide metal ions as model systems. Several novel acylpyrazolones and their amphiphilic analogs have been designed, synthesized, and characterized. Their lanthanide metal ion recognition efficacies have been demonstrated through baseline separations of a mixture of light, middle, and heavy lanthanide metal ions by employing them in the aqueous mobile phase of high performance liquid chromatography (HPLC) with octadecylsilanized silica (ODS) as the stationary phase. The complex separation mechanism is influenced by the structures of acylpyrazolone and amphiphilic moieties, and spontaneous …

Rank-Based Methods For Repeated Measures Data Under Exchangeable Errors, John Kloke

Dissertations

Rank-based estimation methods provide alternatives to least squares. Estimators derived via least squares are generally not robust to aberrant observations.Rank-based methods for linear models generalize traditional Wilcoxon procedures in the simple location models and are robust.

In the usual linear model it is assumed that the errors are independent. In the case of repeated measures data several observations are taken on each experimental unit. In the case of longitudinal data the measures are taken on the same subject over time. As such an independence assumption does not seem valid. A common solution to this is to make an assumption on …

Structure Preserving Algorithms For Computing The Symplectic Singular Value Decom Position, Archara Chaiyakarn

Dissertations

In this thesis we develop two types of structure preserving Jacobi algorithms for com puting the symplectic singular value decomposition of real symplectic matrices and complex symplectic matrices. Unlike general purpose algorithms, these algorithms produce symplectic structure in all factors of the singular value decomposition.

Our first algorithm uses the relation between the singular value decomposition and the polar decomposition to reduce the problem of finding the symplectic singular value decomposition to th a t of calculating the structured spectral decomposition of a doubly structured m atrix. A Jacobi-like m ethod is developed to compute this doubly structured spectral decomposition. …

Stratification And Domination In Graphs And Digraphs, Ralucca M. Gera

Dissertations

In this thesis we combine the idea of stratification with the one of domination in graphs and digraphs, respectively.

A graph is 2-stratified if its vertex set is partitioned into two classes, where the vertices in one class are colored red and those in the other class are colored blue. Let F be a 2-stratified graph rooted at some blue vertex v . An F -coloring of a graph G is a red-blue coloring of the vertices of G in which every blue vertexu belongs to a copy of F rooted at u . The F -domination number γ …

Global Optimality Conditions In Mathematical Programming And Optimal Control, Pariwat Pacheenburawaa

Dissertations

We derive new first-order necessary and sufficient optimality conditions characterizing global minimizers in mathematical programming and optimal controlproblems. These conditions are based on level sets of an objective functional and they do not assume special structure of a problem (convexity, linearity, etc.). For a mathematical programming problem of minimization of a smooth functional on some compact convex set with equality nonlinear constraints, we derive first-order optimality conditions in the form of a generalized Lagrange multiplier rule. This rule should hold for any point from the level set of the objective functional corresponding to a global minimizer. We demonstrate that these …