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数学 & 物理 & 化学 & 力学 : 学术学位
Polarization-division interferometry (PDI) has been demonstrated as a new useful technique in vibrational spectroscopy. The following studies have been accomplished with the PDI. (a) Polarization-division beamsplitters have been constructed with KBr, KRS-5 and mylar substrates and their performance
In this two-part thesis, we study various non-supersymmetric aspects of field theory and string theory.; In part I, we focus on N = 1 supersymmetric gauge theories. Nonperturbative effects in these theories can spontaneously break supersymmetry, a phenomenon known as dynamical supersymmetry break
For some time now, first-principles calculation methods have proven to be an effective tool for investigating the physics of condensed matter systems. The additional use of density functional theory (DFT) and the local density approximation (LDA) has permitted even complex materials to be studied on
Mixture designs and solute-solute interactions in reversed-phase high-performance liquid chromatography.
An overview of the development of reversed-phase high-performance liquid chromatography is presented, including a general discussion of the retention behavior of solutes as a function of several mobile phase properties. Emphasis is placed on pH, ionic strength, surface-active ion, and organic modifi
Semiconductor materials are of great technological and fundamental interest. These materials are at the heart of almost all modern electronic devices and serve as the fundamental testing ground for the electronic structure of solids. While crystalline semiconducting materials are have been extensive
In this dissertation, I will describe a series of experiments and studies that involved ultracold atoms. These atoms have sub-millikelvin temperatures, allowing for unprecedented control and for the possibility of very precise fundamental measurements. In particular, I will concentrate on investigat
Excited H atoms ionized by contemporaneous pulses of collinear static
Fs and linearly polarized microwave F ω cos(ω t + &phis;) electric fields exhibit strong-field resonances as Fs is sl
The electronic structures of the nucleobases, 5-fluorouracil compounds, DNA, metallic DNA, and samples of boron nitride are investigated. Soft X-ray absorption (XAS) and emission (XES) spectroscopy using synchrotron radiation are used to probe the unoccupied and occupied partial densities of electro
Characterisation of copper binding ligands from marine cyanobacterial cultures using voltammetry and mass spectrometry.
Strong copper binding ligands have been produced by Synechococcus DC2 grown exponentially under copper stressed conditions. Using pseudo-polarography, all cultures were found to produce a strong copper binding ligand with a log K' of 24.7, assuming that copper is in the +1 oxidation state. Weaker l
The structures and reactivities of Group 12 metal complexes coordinated by tripodal nitrogen/sulfur ligands possessing internal hydrogen bond donors.
Coordination compounds of nitrogen/sulfur chelate ligands are of interest to the area of bioinorganic chemistry as a means for understanding fundamental chemistry pertaining to metalloenzymes. Of particular interest is the synthesis of model compounds having relevant structural and reactivity charac
The role of topological excitations in frustrated Heisenberg antiferromagnets between two and three spatial dimensions is studied as well as the controversial issue of the order of the phase transition of Heisenberg and XY frustrated antiferromagnets in 3d. The antiferromagnetic Heisenberg model on
The role of non-Condon effects in condensed-phase systems has assumed new importance in the analysis of quantum behavior of unstructured systems including electron transfer in proteins, molecular clamps, and conformational gates in polymeric systems. This work details a novel condensed-phase electro
The work presented here describes the chemistry and applications of new small molecules and polymers in terms of new features with view to procedures, synthesis, and applicability. Chapter one is a general introduction on the field of:Organic Light Emitting Devices (OLEDs) and Organic Photovoltaic C
Photochemical transformations in a water-soluble supramolecular assembly: Spatial and temporal effects on product selectivity.
This dissertation will focus on NMR studies and photochemical experiments performed in a supramolecular host-guest assembly in aqueous media. Cavity of the synthetic resorcinarene based host molecule used in this study acts as a hydrophobic pocket for guests like dibenzyl ketones, N-alkyl-2-pyridone
The fractal operators discussed in this dissertation are introduced in the form originally proposed in an earlier book of the candidate, which proves to be very convenient for physicists, due to its heuristic and intuitive nature. This dissertation proves that these fractal operators are the most co
Torquoselectivity in the Nazarov cyclization of facially biased dienones and their application toward total synthesis of taxinine.
The Nazarov cyclization has emerged as a powerful method for formation of five-membered carbocyclic rings from simple dienone precursors. Its mechanism was shown to proceed by initial conrotatory ring closure of the activated dienone-Lewis acid complex affording an intermediate oxyallyl zwitterions
Single molecule switches and molecular self-assembly: Low temperature STM investigations and manipulations.
This dissertation is devoted to single molecule investigations and manipulations of two porphyrin-based molecules, chlorophyll-a and Co-porphyrin. The molecules are adsorbed on metallic substrates and studied at low temperatures using a scanning tunneling microscope. The electronic, structural and m
The analog linear interpolation approach for Monte Carlo simulation of prompt gamma-ray neutron activation analysis.
The Monte Carlo code (CEARPGA 1) was developed to generate the elemental library spectra required for implementing the Monte Carlo Library Least-Squares algorithm for prompt gamma-ray neutron activation analysis (PGNAA). The existing big weight problem in which a few histories yield very large weigh
A special case of the complex Ginzburg-Landau (CGL) equation possessing a Lyapunov functional is identified. The global attractor of this Lyapunov CGL (LCGL) is studied in one spatial dimension with periodic boundary conditions. The LCGL may be viewed as a dissipative perturbation of the nonlinear S
The aim of this PhD thesis is the study of some diophantine problems. Some of them are related with Pythagorean triples and the others with arithmetical functions.; In particular, chapter 1 begins with two historical notes about Diophantus' Arithmetic and the Plimpton tablet 322, to be followed, in