Liquid metal flow under the influence of heterogeneous magnetic field: numerical study. - In: Proceedings, (2006), S. 194-199
Numerical study of magnetohydrodynamic turbulence in channel flow. - In: Proceedings, (2006), S. 139-144
Simulation and phenomenology of turbulent magnetohydrodynamic channel flow. - In: Turbulence, heat and mass transfer 5, (2006), S. 179-182
A comparative study on the electronic structure of the 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide RT-ionic liquid by electron spectroscopy and first principles calculations. - In: Zeitschrift für physikalische Chemie, ISSN 2196-7156, Bd. 220 (2006), 10, S. 1407-1416
The near-surface electronic structure of the room-temperature ionic liquid 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide has been investigated with ultraviolet and X-ray photoelectron spectroscopy as well as metastable induced electron spectroscopy. The results have been compared with density functional theory calculations. The good agreement between the experimental and theoretical data provides detailed insight into the origin of the observed spectral features. In particular, we found that a simple composition of the spectra of the isolated ions does not suffice to fit to the experimental results, but interionic interactions have to be considered.
http://dx.doi.org/10.1524/zpch.2006.220.10.1407
Exponential distribution of long heart beat intervals during atrial fibrillation and their relevance for white noise behaviour in power spectrum. - In: Journal of biological physics, ISSN 1573-0689, Bd. 32 (2006), 5, S. 383-392
http://dx.doi.org/10.1007/s10867-006-9022-z
Transition to turbulence in magnetohydrodynamic channel flow of liquid metals. - In: NIC Symposium 2006, (2006), S. 341-348
Strong dispersion of the surface optical phonon of silicon carbide in the near vicinity of the surface Brillouin zone center. - In: Surface science, ISSN 1879-2758, Bd. 600 (2006), 14, S. 2886-2893
The surface optical or FuchsKliewer phonons of the (0 0 1) surface of 3C-SiC and the Si-terminated (0 0 0 1) surfaces of 4H- and 6H-SiC have been investigated with high resolution electron energy loss spectroscopy (HREELS). For each of the SiC polytypes the frequency of the surface optical phonon changes with surface reconstruction, indicating subtle differences in the static polarization at differently reconstructed surfaces. Due to their anisotropy, hexagonal surfaces exhibit a second, much weaker FuchsKliewer mode. For all surfaces under examination, a linear dispersion of the FuchsKliewer mode frequency has been found for wave vectors close to the Gamma-point. This dispersion can be explained by dynamical dipole coupling between atomic oscillators at the surface of the highly polar silicon carbide.
http://dx.doi.org/10.1016/j.susc.2006.05.031
Surface phonons of clean, hydrogen- and deuterium-terminated Si(0 0 1) surfaces. - In: Surface science, ISSN 1879-2758, Bd. 600 (2006), 17, S. 3446-3455
We present a comprehensive vibrational study of the clean and hydrogen- or deuterium-terminated silicon (0 0 1) surface. The modes related to the clean as well as to the H:Si, D:Si, and 2H:Si, 2D:Si surfaces are studied by means of high resolution electron energy loss spectroscopy (HREELS). We pay special attention to the modification of the phonon modes by the surface treatments and compare the data with reported experimental and theoretical results. The analysis of the relative phonon intensities of the clean, mono- and dihydride surfaces yields the assignment of the modes related to the dimer bonds. The isotopic shifts of vibrons related to the SiH and SiD bonds and to the surface phonon are discussed and applied to the characterisation of the surface excitations.
http://dx.doi.org/10.1016/j.susc.2006.06.030
Kinetic growth of nanoclusters with perpendicular magnetic anisotropy. - In: epl, ISSN 1286-4854, Bd. 75 (2006), 1, S. 167-173
The growth of binary-alloy clusters on a weakly interacting substrate through codeposition of two atomic species is studied by kinetic Monte Carlo simulation. Our model describes salient features of CoPt3 nanoclusters, as obtained recently by the molecular-beam epitaxy technique. The clusters display perpendicular magnetic anisotropy (PMA) in a temperature window of growth favorable for applications. This temperature window is found to arise from the interplay of Pt surface segregation and aspect ratio for cluster shapes. Conclusions are drawn on how to optimize growth parameters with respect to PMA.
http://dx.doi.org/10.1209/epl/i2006-10085-9
Ion diffusion and mechanical losses in mixed alkali glasses. - In: Journal of non-crystalline solids, ISSN 0022-3093, Bd. 352 (2006), 42/49, S. 5178-5187
Based on general theoretical considerations we show that the fraction cV of vacant sites for the mobile ions in glasses should be small in order to understand the peculiar behavior of the internal friction in the mixed alkali effect. Moreover, for small cV, the steep fall of the conductivity in the dilute foreign alkali region can be explained by a trapping of vacancies induced by the minority ions. To demonstrate our general analysis we study a simple hopping model and show that it allows one to recover both the typical behavior of the internal friction (shifts of single and mixed alkali peak positions with the mixing ratio and associated changes in activation energies, changes of peak heights) and the typical behavior of tracer diffusion coefficients (drastic fall of mobility of one type of ion by replacement with a second type of mobile ion and associated changes in activation energies). Reasonable values of model parameters can be estimated from measured data and predictions are made for experiments.
http://dx.doi.org/10.1016/j.jnoncrysol.2005.12.061