TY - JOUR A1 - Werner, Klaus T1 - X-ray emission from hot hydrogen-deficient white dwarfs Y1 - 1996 ER - TY - JOUR A1 - Hamann, Wolf-Rainer A1 - Heber, Ulrich A1 - Jeffrey, C. S. T1 - Wolf-Rayet stars of high and low mass Y1 - 1996 ER - TY - INPR A1 - Maaß, Peter A1 - Rieder, Andreas T1 - Wavelet-accelerated Tikhonov-Phillips regularization with applications N2 - Contents: 1 Introduction 1.1 Tikhanov-Phillips Regularization of Ill-Posed Problems 1.2 A Compact Course to Wavelets 2 A Multilevel Iteration for Tikhonov-Phillips Regularization 2.1 Multilevel Splitting 2.2 The Multilevel Iteration 2.3 Multilevel Approach to Cone Beam Reconstuction 3 The use of approximating operators 3.1 Computing approximating families {Ah} T3 - NLD Preprints - 30 Y1 - 1996 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14104 ER - TY - JOUR A1 - Sander, Rolf A1 - Herrmann, V. A1 - Menzel, Ralf T1 - Transient absorption spectra and bleaching of 4'-n-Pentyl-4-Cyanoterphenyl in Cyclohexane : determination of cross sections and recovery times Y1 - 1996 ER - TY - JOUR A1 - Okatova, Olga V. A1 - Andreeva, Katharina A. A1 - Schulz, Burkhard T1 - Thermal hydrolytic degradation of polyoxadiazole derivatives Y1 - 1996 ER - TY - JOUR A1 - Wüstneck, Rainer A1 - Krägel, Jürgen A1 - Miller, Reinhard A1 - Wilde, Peter J. A1 - Clark, David C. T1 - The adsorption of surface active complexes between casein lactoglobulin and ionic surfactants and their shear rheological behaviour Y1 - 1996 SN - 0927-7757 ER - TY - JOUR A1 - Seehafer, Norbert A1 - Galanti, B. A1 - Feudel, Fred A1 - Rüdiger, Sten T1 - Symmetry breaking bifurcations for the magnetohydrodynamic equations with helical forcing Y1 - 1996 ER - TY - INPR A1 - Feudel, Fred A1 - Seehafer, Norbert A1 - Galanti, Barak A1 - Rüdiger, Sten T1 - Symmetry breaking bifurcations for the magnetohydrodynamic equations with helical forcing N2 - We have studied the bifurcations in a three-dimensional incompressible magnetofluid with periodic boundary conditions and an external forcing of the Arnold-Beltrami-Childress (ABC) type. Bifurcation-analysis techniques have been applied to explore the qualitative behavior of solution branches. Due to the symmetry of the forcing, the equations are equivariant with respect to a group of transformations isomorphic to the octahedral group, and we have paid special attention to symmetry-breaking effects. As the Reynolds number is increased, the primary nonmagnetic steady state, the ABC flow, loses its stability to a periodic magnetic state, showing the appearance of a generic dynamo effect; the critical value of the Reynolds number for the instability of the ABC flow is decreased compared to the purely hydrodynamic case. The bifurcating magnetic branch in turn is subject to secondary, symmetry-breaking bifurcations. We have traced periodic and quasi- periodic branches until they end up in chaotic states. In particular detail we have analyzed the subgroup symmetries of the bifurcating periodic branches, which are closely related to the spatial structure of the magnetic field. T3 - NLD Preprints - 31 Y1 - 1996 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14317 ER - TY - INPR A1 - Braun, Robert A1 - Feudel, Fred T1 - Supertransient chaos in the two-dimensional complex Ginzburg-Landau equation N2 - We have shown that the two-dimensional complex Ginzburg-Landau equation exhibits supertransient chaos in a certain parameter range. Using numerical methods this behavior is found near the transition line separating frozen spiral solutions from turbulence. Supertransient chaos seems to be a common phenomenon in extended spatiotemporal systems. These supertransients are characterized by an average transient lifetime which depends exponentially on the size of the system and are due to an underlying nonattracting chaotic set. T3 - NLD Preprints - 29 Y1 - 1996 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14099 ER - TY - JOUR A1 - Liperovsky, Viktor A. A1 - Meister, Claudia-Veronika T1 - Sporadic E-layers as current generator Y1 - 1996 ER - TY - JOUR A1 - Hamann, Wolf-Rainer T1 - Spectral analysis and model atmospheres of WR type central stars Y1 - 1996 ER - TY - JOUR A1 - Hamann, Wolf-Rainer A1 - Koesterke, Lars T1 - Spectral analyses with the standard model : Part II: Wolf-Rayet Stars Y1 - 1996 ER - TY - JOUR A1 - Hamann, Wolf-Rainer A1 - Jeffrey, C. S. A1 - Leuenhagen, U. T1 - Spectral analyses of late type central stars of planetary nebulae Y1 - 1996 ER - TY - JOUR A1 - Donval, Ariela A1 - Berkovic, Garry A1 - Yilmaz, Sükrü A1 - Bauer-Gogonea, Simona A1 - Brinker, Walter A1 - Wirges, Werner A1 - Bauer, Siegfried A1 - Gerhard, Reimund T1 - Spatial and thermal analysis of nonlinearity created by asymmetric charge injection Y1 - 1996 ER - TY - JOUR A1 - Liperovsky, Viktor A. A1 - Kustov, A. V. A1 - Meister, Claudia-Veronika T1 - Some ideas concerning the problem of anomalous polar E-region heating due to Farley-Buneman turbulence Y1 - 1996 ER - TY - JOUR A1 - Ostermeyer, Martin A1 - Heuer, Axel A1 - Watermann, V. A1 - Menzel, Ralf T1 - Single rod Nd:laser with phase conjugating SBS-mirror and large transversal mode for average output powers above 20 Watts Y1 - 1996 ER - TY - JOUR A1 - Werner, Klaus T1 - Search for trace amounts of hydrogen in hot DO white dwarfs Y1 - 1996 ER - TY - JOUR A1 - Ostermeyer, Martin A1 - Heuer, Axel A1 - Watermann, V. A1 - Menzel, Ralf T1 - Resonators with phase conjugating SBS-mirror for solid state lasers with high output powers Y1 - 1996 ER - TY - JOUR A1 - Wüstneck, Rainer A1 - Wasow, G. T1 - Relation between the interaction parameter of a generalised Frumkin-Damaskin isotherm and some properties of solutions of surfactant mixtures Y1 - 1996 ER - TY - INPR A1 - Voss, Henning A1 - Kurths, Jürgen A1 - Schwarz, Udo T1 - Reconstruction of grand minima of solar activity from Delta 14 C data : linear and nonlinear signal analysis N2 - Using a special technique of data analysis, we have found out 34 grand minima of solar activity obtained from a 7,700 years long Δ14C record. The method used rests on a proper filtering of the Δ14C record and the extrapolation of verifiable results for the later history back in time. Additionally, we use a method of nonlinear dynamics, the recurrence rate, to back up the results. Our findings are not contradictory to the record of solar maxima resp. minima by Eddy [5], but constitute a considerable extension. Hence, it has become possible to look closer at the validity of models. This way, we have tested several models for solar activity, esp. the model of Barnes et al. [1]. There are hints for that the grand minima might solely be driven by the 209 year period found in the Δ14C record. T3 - NLD Preprints - 28 Y1 - 1996 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14083 ER -