Reports

The present contribution is concerned with the highly lattice-mismatched growth of InPon GaAs-substrates by metalorganic molecular beam epitaxy (MOMBE) using TMIn andprecracked phosphine as the source materials. Here the objective was to deposit device-suitableInP-layers with low surface roughness, dislocation density and electrical conductivity.Growth-optimization of InP on GaAs was carried out by applying a multitudeof characterization methods, amongst others atomic force microscopy, x-ray diffraction,photoluminescence spectroscopy and Hall-effect-measurements. [...]

In palliative pain therapy of cancer patients with bone metastases the longer-lived $\beta^{-}$-emitter$^{89}$Sr (T$_{1/2}$ = 50.5 d) is often used. However, since corpuscular radiation cannot be measuredfrom outside the body, there is a lack of biodistribution data. [...]

In this report, we will first briefly describe the phenomena, underlying mechanisms andnecessary criteria of DDT, then summarize the experimental work on hydrogenexplosion performed at the SWL of RWTH Aachen. Then we will explain the CFDcodes SHOCKIN and AIXCO as well as the applications in the simulation of DDTprocesses.Studies performed at the SWL include three topics: 1) self-ignition phenomena;2) DDT mechanisms in axis-symmery geometry with periodic obstacles or a singleobstacle; and 3) detonation formation at the entrance to narrow gaps. [...]

This report describes the R&D work performed within the scope ofEC/HGF project activities concerning the numerical simulation of reacting flowin complex geometries. The aim is the refinement of numerical methods used incomputational fluid dynamics (CFD) by introducing highperformance computations(HPC) to analyse explosion processes in technical systems in more detail.Application examples concern conventional and nuclear energy systems,especially the safety aspects offuture hydrogen technology.The project work is mainly focused on the modelling of the accident-relatedbehaviour of hydrogen in safety enclosures regarding the distribution andcombustion of burnable gas mixtures, ranging from slow to fast or even rapidflames. [...]

This thesis addresses the development of surface-textured ZnO:Al films prepared bymagnetron sputtering and post deposition wet chemical etching. Technological goal is thedesign of optimised light trapping schemes for amorphous (a-Si:H) and microcrystalline ($\mu$c-Si:H) silicon based thin film solar cells. [...]

Over the last two decades there has been intense theoretical and experimental interestin the physics of low-dimensional electron systems which are predicted to exhibit uniqueelectronic and optical properties. The reduced phase space available for electronscattering in one-dimensional systems - so called quantum wires - is expected to leadto a greatly enhanced mobility. [...]

First measurements on Barkhausen - noise from magnetic tunnel junctions arepresented. A low frequency magnetic field was applied to the magnetic thin film layers andthen the temporary changes in the voltage signal of the junction were measured as spectralnoise density. [...]

Compared to normal conductors, superconductors exhibit extremely small microwavesurface resistances and, thus, provide a number of advantages for the use of thesematerials in microwave applications, e.g. mobile communication. [...]

Die vorliegende Arbeit beschäftigt sich mit der quantitativen Ermittlung derMikrostruktur aperiodischer Objekte auf atomarer Skala mittelsObjektwellenrekonstruktion. Bei der Objektwellenrekonstruktion handelt es sich um eineMethode, bei der die komplexwertige Wellenfunktion an der Unterseite des untersuchtenObjekts aus einem Satz hochauflösender transmissionselektronenmikroskopischerAbbildungen rekonstruiert wird. [...]

Die vorliegende Arbeit ist im Grenzbereich zwischen anatomischer und funktionalerGehirnbildgebung angesiedelt. Ihr Hauptgegenstand sind Diffusions-Messungen, mit denen es möglich ist, mikrostrukturelle Merkmale von Hirngewebezu untersuchen.Meine Interesse für die Gehirnforschung hatte sich bereits in der Oberstufen-Zeit (1992/3) entwickelt [...]