Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 53 for “"Green function"”.
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Surface embedded green function method applied to Ag(111).
… calculations utilizing the Surface Embedded Green Function (SEGF) method have been performed on the Ag(111) surface. Analysis of the surface energetics reveal an energy minimum in the low temperature limit at an outerlayer contraction of 0.5% which agrees well with low energy electron …
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On the numerical evaluation of the Neumann-Kelvin Green function
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1989.
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Green function studies of the interlayer exchange coupling in magnetic multilayers
… method that employed the so called Analytical Green Function (AGF). The results of this approach offered a good checkpoint of RAA, and they were in good agreement with the experimental findings in Fe/Cr and Co/Cu systems. We then calculated the intrinsic biquadratic coupling and compared it to …
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Computation and application of the lattice Green function to dislocations in metals, intermetallics, and semiconductors
… to the dislocation core. Methods such as density functional theory (DFT) are needed to accurately determine the geometry in the dislocation core; however, the long-range strain field of a dislocation is incompatible with periodic boundary conditions, making it challenging to perform DFT …
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Solute transport in magnesium and their uncertainty quantification using density functional theory and green function approach
… hexagonal close-packed Mg. We utilize density functional theory calculations to determine the energies of interstitials and solute-vacancy configurations, which inform our diffusion model. The diffusion of light elemental solutes B, C, N, and O is investigated by determining their stable …
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Judd operator methods in superspace: application to the thermal single particle Green function for the Hubbard dimer
… of the thermal two-time single-particle Green functions may be expressed as matrix elements of the resolvent of the Liouville operator, in an abstract Hilbert space. This abstract Hilbert space (the "superspace") contains elements f, g, etc. which are products of an odd number of fermion …
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Physical Modeling of Graphene Nanoribbon Field Effect Transistor Using Non-Equilibrium Green Function Approach for Integrated Circuit Design
… Schrödinger equations within the non-equilibrium Green’s function (NEGF) formalism. The quantum transport model fully treats short channel-length electrostatic effects and the quantum tunneling effects, leading to the technology exploration of graphene nanoribbon field effect transistors (GNRFETs) …
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Nonequilibrium green function approach to elastic and inelastic spin-charge transport in topological insulator-based heterostructures and magnetic tunnel junctions
… components, maintaining their quality and functionality, and aiming at greater efficiency, economy, and storage characteristics for the corresponding physical devices. The aim of this thesis is to present a contribution to the analysis of the electronic charge and spin transport phenomena …
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Pulsed-Laser Ultrasound Generation in Fiber-Reinforced Composite Material
… This requires a computation of elastodynamic Green function which represents the displacement field from the idealized synthetic sources localized precisely in both space and time. A two-dimensional numerical analysis utilizing a finite difference method for computation of the Green function …
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Potential Theory of Generalized Hyperbolic Processes
… 2, we study the asymptotic behaviors of the Green function of Y t near zero and infinite, and jumping function of Yt near zero. We prove that Harnack inequality is valid for nonnegative harmonic functions of Yt. In chapter 3, we show that the rotationally invariant generalized hyperbolic …
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A three-dimensional technique for predicting first-and second-order hydrodynamic forces on a marine vehicle advancing in waves
… are obtained by solving the three-dimensional Green function integral equations over the mean wetted body surface. The forward speed free surface Green function representing a translating pulsating source potential for infinite water depth and finite water depth is derived using double Fourier …
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Internal tide generation by tall ocean ridges
… an experimental investigation of a pre-existing Green function formulation for internal tide generation by a tall symmetric ridge in a uniform density stratification. A modal decomposition technique was developed to characterize the structure of the experimental wave fields generated by 2D model …
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Applying AdS/CFT to many body systems
… field theory, and calculate the correlation function of a scalar operator in this theory using the AdS/CFT correspondence. We describe numerical techniques for calculating the retarded Green function of the operator. The results suggest that further improvement in the robustness of the codes …
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Internal tide generation by tall ocean ridges
… an experimental investigation of a pre-existing Green function formulation for internal tide generation by a tall symmetric ridge in a uniform density stratification. A modal decomposition technique was developed to characterize the structure of the experimental wave fields generated by 2D model …
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Mathematical Modelling of Novel Ultrasonic Transducers with Fractal-Like Geometries
… on the renormalization approach so that a Green function renormalization method can be utilised. The important operating characteristics for the device are derived, and comparison of metrics between the new device alongside the standard design (Euclidean) and a previously investigated …
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Computation of nonlinear hydrodynamic loads on floating wind turbines using fluid-impulse theory
… offshore floating wind turbines. The time-domain Green function is used to solve the linear and nonlinear free-surface problems and efficient methods are derived for its computation. The body instantaneous wetted surface is approximated by a panel mesh and the discretization of the free surface is …
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An application of the Liouville resolvent method to the study of fermion-boson couplings
… an unconventional technique used for finding a Green function for a Hamiltonian. Implementation of the method entails the calculation of commutators of a second-quantized Hamiltonian operator with particular generalized stepping operators that are elements of a Hilbert space and that represent …
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An SEGF study of the Rh(001) surface.
… has been performed using the surface embedded Green function method. Calculations have been performed by embedding a three-layer slab onto a bulk rhodium substrate. The calculated work function and surface core level shifts are in good agreement with other theoretical work. Additionally, bulk …
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Broadband Multilevel Fast Multipole Methods
… in combination with a decomposition of the Green function. For high frequency simulations, where the wavelength is smaller then the smallest features of the geometry, a propagating plane wave decomposition leads to a very efficient algorithm. Unfortunately, this decomposition fails when the …
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