Sökning: "jump diffusion"

Visar resultat 1 - 5 av 38 avhandlingar innehållade orden jump diffusion.

1. 1. Insights into Materials Properties from Ab Initio Theory : Diffusion, Adsorption, Catalysis & Structure

   Författare :Andreas Blomqvist; Rajeev Ahuja; Christopher Wolverton; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Molecular dynamics; Diffusion; Catalysis; Adsorption; Random structure search; Hydrogen-storage materials; Phase-change materials; Defects and diffusion; Defekter och diffusion; Surfaces and interfaces; Ytor och mellanytor; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : In this thesis, density functional theory (DFT) calculations and DFT based ab initio molecular dynamics simulations have been employed in order to gain insights into materials properties like diffusion, adsorption, catalysis, and structure. In transition metals, absorbed hydrogen atoms self-trap due to localization of metal d-electrons. LÄS MER

3. 2. Theory of Hydrogen Quantum Diffusion

   Författare :Thomas Mattsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; path-integrals; isotope effect; transition state theory; quantum; diffusion; hydrogen; first-principles calculations; nickel;

   Sammanfattning : Atomic hydrogen adsorbed on a metal surface is one of the simplest possible examples of chemisorption, yet it is very challenging. The adsorption and the very elementary process of surface diffusion, a single atomic jump, have been investigated theoretically using several methods. LÄS MER

4. 3. Stochastic Simulation of Multiscale Reaction-Diffusion Models via First Exit Times

   Författare :Lina Meinecke; Per Lötstedt; Stefan Engblom; Ramon Grima; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computational systems biology; diffusion; first exit times; unstructured meshes; reaction-diffusion master equation; macromolecular crowding; excluded volume effects; finite element method; backward analysis; stochastic simulation; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Sammanfattning : Mathematical models are important tools in systems biology, since the regulatory networks in biological cells are too complicated to understand by biological experiments alone. Analytical solutions can be derived only for the simplest models and numerical simulations are necessary in most cases to evaluate the models and their properties and to compare them with measured data. LÄS MER

5. 4. Diffusion in Poly(vinyl alcohol) and Polyethylene as Determined by Computational Simulations and Modeling

   Författare :Gunnar Karlsson; KTH; []
   Nyckelord :Molecular dynamics; simulation; modeling; polymer; poly vinyl alcohol ; polyethylene; water; oxygen; limonene; solute; diffusion; transport properties;

   Sammanfattning : Poly(vinyl alcohol) and polyethylene polymer systems werebuilt in order to study their transport properties (diffusion).First a verification of the AMBER force field was conducted fora poly(vinyl alcohol) system built from a chain with 145repeating units. NPT-molecular dynamics simulations attemperatures between 400 and 527 K were performed. LÄS MER

7. 5. Valuation and Optimal Strategies in Markets Experiencing Shocks

   Författare :Hannah Dyrssen; Erik Ekström; Damien Lamberton; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; American options; optimal stopping; game options; jump diffusion; jump to default; free-boundary problems; early exercise premium; integral equation; parabolic pde; convexity; sequential testing; fixed-point approach; Mathematics with specialization in Applied Mathematics; Matematik med inriktning mot tillämpad matematik;

   Sammanfattning : This thesis treats a range of stochastic methods with various applications, most notably in finance. It is comprised of five articles, and a summary of the key concepts and results these are built on.The first two papers consider a jump-to-default model, which is a model where some quantity, e.g. LÄS MER