Rudy Klein

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We study the process of diffusion-limited colloid aggregation (DLCA) using both static and dynamic light scattering. Static light scattering is used to measure the fractal dimension of the clusters as well as their structure factor, which is found to be in good agreement with that obtained from calculation using computer-generated clusters. Dynamic light(More)
Exposing pressurized crystals to GeV heavy ions reveals unexpected structural changes. Irradiated at ambient conditions, natural zirconia (ZrO2) transforms from the monoclinic structure to its tetragonal (high-temperature) phase. For this process the required fluence must exceed 5×10 12 ions/cm 2 for Pb and U, and become even significantly higher for(More)
In this paper we report on the charging behavior of latex particles in aqueous suspensions. We use static light scattering and acid-base titrations as complementary techniques to observe both effective and bare particle charges. Acid-base titrations'at various ionic strengths provide the pH dependent charging curves. The surface chemical parameters(More)
The structure of fractal colloid aggregates formed in both the diffusion-and the reaction-limited regimes is studied by static light scattering experiments. The crossover region of the structure factor of the clusters is measured, and the effects of the finite extent of the fractal structure on the scattering are investigated. The polydispersity of the(More)
Boron nitride (BN) shows similarities to carbon, having a hexagonal (graphite-like) structure (hBN) and a cubic diamond type (cBN). Under ambient temperature conditions, hBN transforms irreversibly into wurtzitic BN (wBN) at pressures above 10.8 GPa [1]. We investigated the influence of ion irradiation on this displacive phase transition using in situ Raman(More)
Aims. The earliest stages of intermediate-and high-mass star formation remain poorly understood. To gain deeper insights, we study a previously discovered protostellar source that is deeply embedded and drives an energetic molecular outflow. Methods. The source, UYSO 1, located close to IRAS 07029–1215 at a distance of about 1 kpc, was observed in the(More)
Dust formation in brown dwarf atmospheres is studied by utilising a model for driven turbulence in the mesoscopic scale regime. We apply a pseudo-spectral method where waves are created and superimposed within a limited wavenumber interval. The turbulent kinetic energy distribution follows the Kolmogoroff spectrum which is assumed to be the most likely(More)
We present the first complete infrared spectrum of a molecular cloud core covering the wavelength region from 2.4 up to 200 µm together with a map at 1.3 mm wavelength and near-infrared (NIR) images. The core is located in the northern part of M 17 and shows strong evidence for ongoing star formation. These data are the first step towards a complete(More)
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