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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Experimental investigations of the electronic interactions within multinuclear first row transition metal complexes

Tilford, Claire January 1999 (has links)
No description available.
42

Topics in many-particle quantum systems. / 多體量子系統問題 / Topics in many-particle quantum systems. / Duo ti liang zi xi tong wen ti

January 2005 (has links)
Lo Loc Ping = 多體量子系統問題 / 盧樂平. / Thesis submitted in: October 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 168-171). / Text in English; abstracts in English and Chinese. / Lo Loc Ping = Duo ti liang zi xi tong wen ti / Lu Leping. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgment --- p.iii / Chapter I --- Computational Quantum Mechanics and Its Applications 電算量子力學及其應用 --- p.1 / Chapter 1 --- An Overview of Quantum Mechanics and Some Important Tools of Theory --- p.2 / Chapter 1.1 --- The Schrodinger Equation --- p.2 / Chapter 1.2 --- The Variational Method --- p.4 / Chapter 1.2.1 --- Rayleigh-Ritz Approach --- p.4 / Chapter 1.2.2 --- Linear Variation --- p.5 / Chapter 2 --- Theoretical Methodology of Electronic Structures: Ab Initio Molecular Orbital Theory --- p.7 / Chapter 2.1 --- The Molecular Hamiltonian --- p.7 / Chapter 2.2 --- Hartree Description and Linear Combination of Atomic Orbitals Expan- sion --- p.8 / Chapter 2.3 --- Slater Determinant and the Pauli Exclusion Principle --- p.9 / Chapter 2.4 --- The Expansion of E in Terms of Integrals over MOs --- p.11 / Chapter 2.5 --- Derivation of the Hartree´ؤFock Equations --- p.15 / Chapter 2.6 --- The Self-Consistent Field Calculation --- p.18 / Chapter 2.7 --- Koopmans' Theorem --- p.19 / Chapter 2.8 --- Orbital and the Total SCF Electronic Energy --- p.20 / Chapter 2.9 --- AO Basic Sets --- p.21 / Chapter 2.9.1 --- Slater-Type Orbitals --- p.21 / Chapter 2.9.2 --- Gaussian Functions --- p.22 / Chapter 2.10 --- The Hartree-Fock Limit --- p.23 / Chapter 2.11 --- Electron Correlation --- p.23 / Chapter 2.11.1 --- Weakness in the Single Determinant Model --- p.23 / Chapter 2.11.2 --- Configuration Interaction --- p.24 / Chapter 2.11.3 --- The Coupled-Cluster Method --- p.25 / Chapter 2.11.4 --- Density Functional Theory --- p.26 / Chapter 2.12 --- Frontier Orbitals --- p.31 / Chapter 3 --- Theoretical Investigation of the Interaction between Metal and Tris(8- hydroxyquinoline) aluminum in Organic Light Emitting Diodes --- p.32 / Chapter 3.1 --- Organic Light Emitting Diodes and Tris(8-hydro-xyquinoline) aluminum --- p.32 / Chapter 3.2 --- Computational Methodology --- p.33 / Chapter 3.3 --- Alq3 --- p.34 / Chapter 3.3.1 --- Molecular Structure --- p.34 / Chapter 3.3.2 --- Electronic Structure --- p.36 / Chapter 3.3.3 --- Transition and Relaxation Energies --- p.44 / Chapter 3.3.4 --- Interactions with Metals --- p.45 / Chapter 3.4 --- "Li-Alq3, Na-Alq3 and K-Alq3 Complexes" --- p.46 / Chapter 3.4.1 --- Molecular Structure --- p.46 / Chapter 3.4.2 --- Ground-State Electronic Structure --- p.55 / Chapter 3.4.3 --- Transition and Relaxation Energies --- p.67 / Chapter 3.5 --- "Be-Alq3, Mg´ؤAlq3 and Ca´ؤAlq3 Complexes" --- p.68 / Chapter 3.5.1 --- Molecular Structure --- p.68 / Chapter 3.5.2 --- Ground-State Electronic Structure --- p.76 / Chapter 3.5.3 --- Transition and Relaxation Energies --- p.87 / Chapter 3.6 --- "B-Alq3, Al-Alq3 and Ga-Alq3 Complexes" --- p.87 / Chapter 3.6.1 --- Molecular Structure --- p.87 / Chapter 3.6.2 --- Ground-State Electronic Structure --- p.95 / Chapter 3.6.3 --- Transition and Relaxation Energies --- p.106 / Chapter II --- Analytical Studies of Polarons and the Electron-Phonon Interaction 極子與電子一聲子相互作用的 解析研究 --- p.107 / Chapter 4 --- Optimal Coupled-Cluster Approximation of the Ground-State Energy of the E× (α1 + α1) Jahn-Teller System --- p.108 / Chapter 4.1 --- The Jahn-Teller Effect --- p.108 / Chapter 4.2 --- Approximation in the Coupled-Cluster Method and the Jahn-Teller Hamiltonian --- p.110 / Chapter 4.3 --- Variational Coupled-Cluster Approximation --- p.112 / Chapter 4.3.1 --- The Zeroth Level --- p.113 / Chapter 4.3.2 --- The First Level --- p.113 / Chapter 4.3.3 --- The Second and the Third Levels --- p.114 / Chapter 4.4 --- An 'Optimal' Hamiltonian --- p.115 / Chapter 4.5 --- Treatment for the k> 1 Case --- p.117 / Chapter 4.6 --- Energies and Other Physical Phenomena --- p.118 / Chapter 5 --- Small-to-Large Ground-State Polaron Crossover in One-Dimension Extended E×e Jahn-Teller System Using Variational Coupled-Cluster Approximation --- p.134 / Chapter 5.1 --- Polaron Formation --- p.134 / Chapter 5.2 --- Model Hamiltonian and the MLF Transformation --- p.135 / Chapter 5.3 --- Variatonal Coupled-Cluster Approximation --- p.137 / Chapter 5.3.1 --- Zeorth Level --- p.139 / Chapter 5.3.2 --- First Level --- p.139 / Chapter 5.3.3 --- Second Level --- p.142 / Chapter 5.4 --- Energies and Static Correlation Functions --- p.142 / Chapter 5.5 --- Approximate Form of the MLF Transformation for K = 0 --- p.153 / Chapter 5.5.1 --- Zeroth Level --- p.154 / Chapter 5.5.2 --- First Level --- p.155 / Chapter 5.5.3 --- Second Level --- p.156 / Chapter 5.5.4 --- Energies and Static Correlation Functions --- p.157 / Chapter 5.6 --- Synopsis --- p.167 / Bibliography --- p.171
43

The interface effect on Magnetoresistance and Magnetization of La0.7Ce0.3MnO3 and La0.7Ca0.3MnO3 thin films

Hung, Chen-Yung 04 July 2004 (has links)
Hole-doped manganite La0.7Ca0.3MnO3 (LCMO) was extensively studied because of its colossal magnetoresistance (CMR) characteristic in a magnetic field. Recently, a new member of CMR family La0.7Ce0.3MnO3 (LCeMO), an electron-doped manganite, raises a new wave of attention for possible application in p-n junction. In this present study, LCMO and LCeMO single layer and bi-layer were grown on SrTiO3 (100) substrate by a pulse laser ablation technique. Due to the neutralization at the p-n junction a possible insulating layer with the anti-ferromagnetic (AFM) property is expected. There is no systematically study of this matter up to date, thus, it is worth to systematically investigate the physical properties of this junction. The result indicates the possible neutralization layer exhibits huge resistance comparison with two lateral layers, the bias current is constrained on the limited thickness of the top layer, which implies the neutralization layer forms a depletion layer that block the current to flow through to the bottom layer. Its electric and magnetic properties may similar to the parent compound LaMnO3 with insulating and anti-ferromagnetic characteristics. Separated by this possible layer, the magnetic coupling between lateral layers is weak. However, the possible AFM layer does pin the magnetic moment of the top layer along the direction perpendicular to the substrate that make a distinct magnetoresistance at low magnetic field.
44

The study of charge ordering in colossal magnetoresistance

Lee, Kung-Chieh 09 January 2006 (has links)
Hole-doped maganite with middle to narrow bandwidth La1-xCaxMnO3 was extensively studied because of its colossal magnetoresistance (CMR) characteristic under a magnetic field. These kind of materials show un- common magnetic and electric properties. The charge order phase only happens to the region x> 0.5, and along with decreasing temperature, its phase goes from para-insulator to charge-ordered then to antiferromagne- tism. In our studies, we apply correlation function of Green¡¦s function to LCMO and get susceptibility of charge and spin. Then we can get the cri- tical value of Coulomb repulsion inside the material by substituting the experimental values of phase transition temperature. This critical values is the key point of charge-ordered. Then we can also get the size of char- ge gap which decides the stability of charge-ordered phase. After know- ing the Coulomb repulsion and charge gap, we can picture the relation of inside and on-site Coulomb repulsion qualitatively while the transition happens. Here the on-site Coulomb repulsion means to the Hund¡¦s coupl- ing between d electrons. And by this we¡¦ll understand the physics inside CMR materials.
45

Spectroscopic Detection and Characterization of Jet-Cooled Transient Molecules

Gharaibeh, Mohammed 01 January 2012 (has links)
Transient molecules are of great importance due to their critical role as intermediates in the semiconductor industry, in upper atmosphere reactions, and in astrochemistry. In the present work, reactive intermediates were produced in the laboratory by applying an electric discharge through a suitable precursor gas mixture and studied by means of their laser-induced fluorescence and emission spectra. The band systems of and have been studied in detail. The energy levels of both isotopologues were fitted with a Renner-Teller model, and the isotope relations have been used to test the validity of the derived parameters. The A2Πu - X 2Πg electronic transition of jet-cooled has been detected and shown to originate from the Ω=3/2 spin-orbit component of v=0 of the ground state. For the first time, the 0-0 band has been identified and vibrational assignments have been made. Our ab initio studies show that the extensive observed perturbations are due to spin-orbit interaction between A2Πu(3/2) and B2Δu(3/2) states. The experimental data were fitted to an effective Hamiltonian and yielded the spin-orbit coupling term =240 cm-1. LIF and emission spectra of the transition of N2O+ have been recorded. Both spin-orbit components of the band were studied at high resolution and rotationally analyzed, providing precise molecular constants. Emission spectra provided extensive data on the ground state vibrational levels which were fitted to a Renner-Teller model including spin-orbit and Fermi resonance terms. The previously unknown electronic spectrum of the H2PO radical has been identified. Ab initio predictions were used to aid in the analysis of the data. The band system is assigned as the electronic transition. The excited state molecular structure was determined by rotational analysis of high resolution LIF spectra. The band systems of the HBCl and DBCl free radicals have been studied in detail. This electron promotion involves a linear-bent transition between the two Renner-Teller components of what would be a 2Π electronic state at linearity. Ab initio potential energy surface calculations were used to help in assigning the LIF spectra which involve transitions from the ground state zero-point level to high vibrational levels of the excited state.
46

The Diffusion Of Financial Innovation In Turkey: The Case Of Atm

Guner, Mine Sule 01 July 2005 (has links) (PDF)
This study investigates the indicators of the number of ATMs (automated teller machines) in the provinces of Turkey by examining two banks: T.C. Ziraat Bankasi and T. iS Bankasi. The study depends on annual panel data from 1990 to 2004 for seventy-three provinces of Turkey. The information about the number of ATMs of the two banks is gathered after a study in the archives of the banks. In this study it is concluded that the number of ATMs of T. iS Bankasi and T. C. Ziraat Bankasi in the previous year and the total number of branches of the banks in Turkey are the indicators of ATM adoption for both of the banks concerned. However, population has a negative sign for T. C. Ziraat Bankasi which is a state bank whereas it has a positive sign for T. iS Bankasi which is a quasi-private bank. The findings also indicate that the ATM number of T. iS Bankasi is more sensitive to the number of total bank branches.
47

Simulações entrópicas do modelo de Ashkin-Teller / Entropic simulation of the model of Shkin-Teller

Ferreira, Lucas de Souza 10 March 2016 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-09-30T21:08:58Z No. of bitstreams: 2 Dissertação - Lucas de Souza Ferreira - 2016.pdf: 964364 bytes, checksum: 53a985295d81269cf08a064398f305f0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-10-03T12:57:01Z (GMT) No. of bitstreams: 2 Dissertação - Lucas de Souza Ferreira - 2016.pdf: 964364 bytes, checksum: 53a985295d81269cf08a064398f305f0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-03T12:57:01Z (GMT). No. of bitstreams: 2 Dissertação - Lucas de Souza Ferreira - 2016.pdf: 964364 bytes, checksum: 53a985295d81269cf08a064398f305f0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-03-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In 1943, Ashkin and Teller (AT) proposed a model to describe the behavior of a system composed by four components that interact with each other. However the problem has not been solved analytically for all parameters due to the complexity of the model. Only thirty years later Fan (1972) proposed a change in order to analyze the system. He made an analogy with the Ising model and described the interactions between the components in terms of spins, leading to a simple matching with the Ising and Potts q = 4 models and, enabling therefore a clearer comprehension of the model and allowing the implementation of various techniques to investigate the behavior of the system with the temperature. In 2001 Wang and Landau developed a Monte Carlo algorithm that estimates directly the density of states and can be applied in the study of phase transitions and the thermodynamic properties. This algorithm is based on a random walk in the space of energies that leads to an estimate for the density of states. During the simulations an energy histogram monitors the evolution of the density of states: whenever the flatness criterion is satisfied, we obtain a finer level of the density of states. In this work we perform a study of the Ashkin-Teller model using the Wang-Landau algorithm, determining the behavior of the magnetization and the specific heat and estimating the critical exponents , and and the critical temperature through the finite-size theory for different values of the model parameters. / Em 1943, Ashkin e Teller (AT) propuseram um modelo para descrever o comportamento de um sistema composto por quatro componentes que interagem entre si. Todavia o problema não foi resolvido analiticamente para todos parâmetros do sistema devido à complexidade de modelo. Somente trinta anos após a publicação do trabalho Fan (1972) propôs uma mudança na forma de analisar o sistema. Ele fez uma analogia com o modelo de Ising e escreveu as interações entre as componentes em termos de spins, o que levou a uma fácil correspondência com os modelos de Ising e Potts q = 4 e, de certa forma, tornou mais clara a compressão do modelo e possibilitou a aplicação de várias técnicas para se obter o comportamento do sistema com a temperatura. Em 2001 Wang e Landau elaboraram um algoritmo de Monte Carlo que estima diretamente a densidade de estados e pode ser aplicado no estudo de transições de fase e propriedades termodinâmicas. Esse algoritmo é baseado em um passeio aleatório no espaço das energias em que constroi-se uma estimativa da densidade de estados juntamente com um histograma de energia: toda vez que o critério de nivelamente é satisfeito, obtêm-se um nível mais refinado da densidade de estados. Este trabalho tem como objetivo o estudo do modelo de Ashkin-Teller usando o algoritmo de Wang-Landau, para o qual, determinamos o comportamento da magnetização e calor específico bem como os expoentes críticos , e e a temperatura crítica, através da teoria de tamanho finito para diferentes conjuntos de parâmetros do modelo.
48

Analysis Of Discrete-Time Queues With Applications To ATM Based B-ISDNs

Gangadhar, Nandyala Dhani 03 1900 (has links) (PDF)
No description available.
49

An exploratory investigation into the feasibility of turning the student identification card into a debit card: The case for the University of the Western Cape

Osambo, Okoko January 2003 (has links)
Magister Commercii - MCom / This study investigates the financial, marketing as well as technological feasibility of turning the current University of Western Cape (UWC) Student ID Card into a more featured debit card called the "Hoop Kaarf'. This debit card will offer the functionality of access to secure UWC areas, the purchase and use of photocopying credits, the purchase of printing credits, taking out library books; and identification, as the old student card does. It will also have the added functionality of replacing cash when paying for vending machines, cafés, takeaways, shops, supermarkets and withdrawing money from ATMs, at UWC, within South Africa and outside the country.
50

Wärmeübertragung durch überlagerte Strömungen an gestapelte Güter am Beispiel des Flachgeschirr-Brandes in Durchlauföfen

Lorenz, Lars 04 October 2007 (has links)
Der Wärmeübergang an gestapelte Güter spielt eine wesentliche Rolle bei der ökonomischen Auslegung von Thermoprozessanlagen. Gleichungen für die Wärmeübertragung an solch komplexe Geometrien sind aber nicht, bzw. nur in stark vereinfachter Form vorhanden. In der vorliegenden Arbeit wurde die Wärmeübertragung für die komplexe Geometrie "Tellerstapel" sowohl experimentell als auch mit Hilfe von Computersimulation bestimmt. Die Ergebnisse beider Methoden zeigen gute bis sehr gute Übereinstimmung. Des Weiteren wurde der Wärmeübergang durch Strahlung mit in die Simulation einbezogen und sein Verhältnis gegenüber dem konvektiven Wärmeübergang ermittelt. Für die Wärmeübergangsberechnung bei anderen Geometrien gestapelter Güter wurden mehrere Wege aufgezeigt und auf die zeit- und kostensparende Nutzung moderner Simulationsmethoden hingewiesen.

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