Browsing Masters Degrees (Physics) by Title
Now showing items 72-91 of 134
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Natural radioactivity in soils of Ijero, Nigeria: measurements and risk assessment
(Stellenbosch : Stellenbosch University, 2019-12)ENGLISH ABSTRACT: Several soil samples were obtained from Ijero, Nigeria, where the chemical and radio-toxicity of soil is under question due to ongoing and unregulated mining activities. The soil samples were crushed, ... -
A near infrared femtosecond laser source for observation of charge transfer processes in semiconductors
(Stellenbosch : Stellenbosch University, 2017-03)ENGLISH ABSTRACT : Near infrared femtosecond laser pulses were generated in the spectral range 900 - 2400 nm using the idler of a noncollinear optical parametric amplifier (NOPA). The amplitude and phase of four exemplary ... -
A new femtosecond electron diffractometer for structural dynamics experiments at cryogenic temperatures
(Stellenbosch : Stellenbosch University, 2014-12)ENGLISH ABSTRACT: In this thesis, a femtosecond electron diffraction (FED) set-up that is capable of investigating the photo-induced switching of Cu(DCNQI)2 from being an insulator to being a conductor is presented. ... -
A non-commutative walecka model as an effective theory for interacting nucleons of finite size
(Stellenbosch : Stellenbosch University, 2012-03)ENGLISH ABSTRACT: The nite size of nucleons should play an important role in the description of high density nuclear matter as found in astro-physical objects. Yet we see that the Walecka model, which is generally used ... -
Non-linear effects in quantum electrodynamics
(Stellenbosch : University of Stellenbosch, 2010-12)ENGLISH ABSTRACT: See abstract in full text -
Non-perturbative flow equations from continuous unitary transformations
(Stellenbosch : University of Stellenbosch, 2005-12)The goal of this thesis is the development and implementation of a non-perturbative solution method for Wegner’s flow equations. We show that a parameterization of the flowing Hamiltonian in terms of a scalar function ... -
Noninvasive measurement of dynamic correlations in spin systems
(Stellenbosch : Stellenbosch University, 2017-12)ENGLISH ABSTRACT : Dynamic correlations hψ| O1(t1)O2(t2)|ψi of quantum observables are useful quantities for the study of quantum dynamics. Attempts at measuring these correlations are however complicated, due to the ... -
Nuclear reactions with polarized spin-1/2 beams
(Stellenbosch : Stellenbosch University, 1990-03)ENGLISH ABSTRACT: The first part of the thesis deals with the subject of polarization in nuclear reactions. The case where the incoming beam is polarized, is emphasized, and the theory is developed for the simple and ... -
Numerical design of an optical solid-state amplifier
(Stellenbosch : Stellenbosch University, 2007-12)Please refer to full text for abstract -
Numerical modelling of the excitation of polyatomic molecules by femtosecond laser beams
(Stellenbosch : University of Stellenbosch, 2011-03)ENGLISH ABSTRACT: The selective excitation of an arbitrary vibrational level of a polyatomic molecule, without passage through an intermediary electronic excited state is demonstrated. This was achieved by simulating the ... -
On evolutionary algorithms for effective quantum computing
(Stellenbosch : Stellenbosch University, 2012-03)ENGLISH ABSTRACT: The goal of this thesis is to present evolutionary algorithms, and demonstrate their applicability in quantum computing. As an introduction to evolutionary algorithms, it is applied to the simple but ... -
One-dimensional fluid model with oscillating, exponentially decaying pair interactions
(Stellenbosch : Stellenbosch University, 2015-12)ENGLISH ABSTRACT: For a one-dimensional fluid model where the pair interaction potential between the molecules consists of a hard core and an exponential attraction, Kac has shown that the partition function can be ... -
Optical tweezers for advanced microscopy
(Stellenbosch : Stellenbosch University, 2018-03)ENGLISH SUMMARY: The integration of lasers into microscopy has enabled new areas of research and expanded existing ones. Not only can one now image samples to resolutions and contrast unheard of before lasers became ... -
Optimized discharge excitation techniques for short pulse gas lasers : TEA CO2 laser
(Stellenbosch : Stellenbosch University, 2013-12)ENGLISH ABSTRACT: Transversely excited atmospheric (TEA) CO2 lasers have found numerous established and potential applications in both industry and research. However, the development of laser systems which can meet the ... -
A path integral approach to the coupled-mode equations with specific reference to optical waveguides
(Stellenbosch : University of Stellenbosch, 2009-03)The propagation of electromagnetic radiation in homogeneous or periodically modulated media can be described by the coupled mode equations. The aim of this study was to derive analytical expressions modeling the solutions ... -
Photoinduced charge dynamics in indoline-dye sensitised solar cells
(2014-12)ENGLISH ABSTRACT: The demand for renewable energy sources has grown out of the humanity’s increasing need for electricity as well as depleting fossil fuel reserves. Organic-dye sensitised solar cells were developed as a ... -
Point spread function engineering for fluorescence microscopy
(Stellenbosch : Stellenbosch University, 2018-03)ENGLISH SUMMARY: A tool for biological imaging is developed within this work. It consists of engineering the point spread function (PSF) of a fluorescent molecule or a nanoparticle emitter by modulating the phase of the ... -
Polymer networks at surfaces
(Stellenbosch : Stellenbosch University, 2003-03)ENGLISH ABSTRACT: In this thesis the formation and properties of a polymer gel on and at a surface are investigated. The gel under investigation is defined as a three-dimensional network of macromolecules that form ... -
Polymer networks with mobile force-applying crosslinks
(Stellenbosch : University of Stellenbosch, 2011-03)ENGLISH ABSTRACT: We construct and study a simple model for an active gel of exible polymer filaments crosslinked by a molecular motor cluster that perform reversible work while translating along the filaments. The ... -
Portable X-ray fluorescence and nuclear microscopy techniques applied to the characterisation of southern African rock art paintings
(Stellenbosch : Stellenbosch University, 2014-04)ENGLISH ABSTRACT: Non-destructive portable X-ray Fluorescence (pXRF) and Particle Induced X-ray Emission (PIXE) were used to measure the elemental concentration of rock art fragment paintings. For pXRF the Amptek Silicon ...
