TY - JOUR A1 - Rosenblum, Michael A1 - Kurths, Jürgen A1 - Pikovskij, Arkadij A1 - Schafer, C. A1 - Tass, Peter A1 - Abel, Hans-Henning T1 - Synchronization in Noisy Systems and Cardiorespiratory Interaction Y1 - 1998 ER - TY - BOOK ED - Mikelskis, Helmut ED - Wilke, Hans-Joachim T1 - Physik plus : Kl. 6, Lehrerbd., mit Kopiervorlagen, Sek. 1 Sachsen Y1 - 1998 SN - 3-06-022240-1 PB - Volk-und-Wissen-Verl. CY - Berlin ER - TY - BOOK ED - Mikelskis, Helmut ED - Wilke, Hans-Joachim T1 - Physik plus : Kl. 6, [Hauptbd.], Sek. 1 Sachsen Y1 - 1998 SN - 3-06-020641-4 PB - Volk-und-Wissen-Verl. CY - Berlin ER - TY - BOOK ED - Mikelskis, Helmut ED - Wilke, Hans-Joachim T1 - Physik plus : Kl. 6, Arbeitsh., Sek. 1 Sachsen Y1 - 1998 SN - 3-06-020643-0 PB - Volk-und-Wissen-Verl. CY - Berlin ER - TY - JOUR A1 - Mikelskis, Helmut A1 - Mikelskis-Seifert, Silke T1 - Physikunterricht aktiv und interaktiv : Workshop-Ansatz mit dem Simulationsprogramm "penOpt" Y1 - 1998 ER - TY - JOUR A1 - Abel, Markus A1 - Flach, S. A1 - Pikovskij, Arkadij T1 - Localisation in a coupled standard map lattice N2 - We study spatially localized excitations in a lattice of coupled standard maps. Time-periodic solutions (breathers) exist in a range of coupling that is shown to shrink as the period grows to infinity, thus excluding the possibility of time-quasiperiodic breathers. The evolution of initially localized chaotic and quasiperiodic states in a lattice is studied numerically. Chaos is demonstrated to spread Y1 - 1998 UR - http://www.stat.physik.uni-potsdam.de/~markus/papers/PhD119-4.ps.gz ER - TY - JOUR A1 - Kuznetsov, Sergey P. A1 - Feudel, Ulrike A1 - Pikovskij, Arkadij T1 - Renormalization group for scaling at the torus-doubling terminal point N2 - The quasiperiodically forced logistic map is analyzed at the terminal point of the torus-doubling bifurcation curve, where the dynamical regimes of torus, doubled torus, strange nonchaotic attractor, and chaos meet. Using the renormalization group approach we reveal scaling properties both for the critical attractor and for the parameter plane topography near the critical point. Y1 - 1998 ER - TY - JOUR A1 - Pikovskij, Arkadij A1 - Politi, Antonio T1 - Dynamic localization of Lyapunov vectors in space-time chaos N2 - We study the dynamics of Lyapunov vectors in various models of one-dimensional distributed systems with spacetime chaos. We demonstrate that the vector corresponding to the maximum exponent is always localized and the localization region wanders irregularly. This localization is explained by interpreting the logarithm of the Lyapunov vector as a roughening interface. We show that for many systems, the `interface' belongs to the Kardar-Parisi- Zhang universality class. Accordingly, we discuss the scaling behaviour of finite-size effects and self-averaging properties of the Lyapunov exponents. Y1 - 1998 ER - TY - JOUR A1 - Abel, Markus A1 - Spicci, M. T1 - Nonlinear localization periodic solutions in a coupled map lattice N2 - We prove the existence of nonlinear localized time-periodic solutions in a chain of symplectic mappings with nearest neighbour coupling. This is a class of systems whose behaviour can be seen as representation of a lattice of pendula. The effect of discrete time changes the mathematical as well as the numerical procedures. Applying the discrete version of Floquet theory eases and clarifies the procedure of proving the existence of the localized time-periodic solutions. As an extension of the concept of rotobreathers one can produce solutions which rotate at every site of the lattice. To consider these we use a general definition of localization. Y1 - 1998 UR - http://www.stat.physik.uni-potsdam.de/~markus/papers/PhD119-22.ps.gz ER - TY - JOUR A1 - Wilkens, Martin T1 - Quantum Phase of a Moving Dipole N2 - It is shown that a neutral particle with an electric dipole moment which moves in a magnetic field acquires a topological phase. This phase may be observed in atom or molecular interferometry. Y1 - 1998 ER - TY - JOUR A1 - Langer, Norbert A1 - Heger, Alexander A1 - Garcia-Segura, Guillermo T1 - Massive stars : the pre-supernova evolution of internal and circumstellar structure Y1 - 1998 ER - TY - JOUR A1 - Lucht, Sylvia A1 - Stumpe, Joachim A1 - Rutloh, M. T1 - Triple fluorescence of substituted benzanilides in solution and in solid states Y1 - 1998 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Janietz, Dietmar A1 - Schmidt, C. A1 - Wendorff, Joachim Heinz T1 - Liquid crystalline 1,3,5-triazines incorporating rod-like azobenzene sub-units Y1 - 1998 ER - TY - JOUR A1 - Goldmann, Daniela A1 - Mahlstedt, S. A1 - Janietz, Dietmar A1 - Busch, P. A1 - Schmidt, C. A1 - Stracke, A. A1 - Wendorff, Joachim Heinz T1 - Mesomorphic donor-acceptor twin molecules with covalently linked sheet-like pentaalkyne and nitrofluorenone subunits Y1 - 1998 ER - TY - JOUR A1 - Otto, Andreas H. A1 - Steiger, Th. A1 - Schrader, Sigurd T1 - The gas phase acidity of trifluoromethanesulphonic acid : an ab initio MO and density functional theory study Y1 - 1998 ER - TY - JOUR A1 - Makievski, A. V. A1 - Fainerman, V. B. A1 - Bree, M. A1 - Wüstneck, Rainer A1 - Krägel, Jürgen A1 - Miller, Reinhard T1 - Asdorption of proteins at the liquid/air interface Y1 - 1998 ER - TY - JOUR A1 - Driebe, Thomas A1 - Blöcker, Thomas A1 - Herwig, Falk A1 - Schönberner, Detlef T1 - Diffusive overshooting in hot bottom burning AGB models Y1 - 1998 ER - TY - JOUR A1 - Brehmer, Ludwig T1 - Supramolecular architectures for micro-sensorics and molecular electronics Y1 - 1998 ER - TY - INPR A1 - Volosevich, Alexandra V. A1 - Meister, Claudia-Veronika T1 - Nonlinear interaction of Farley-Buneman waves N2 - The nonlinear interaction of waves excited by the modified two-stream instability (Farley-Buneman instability) is considered. It is found that, during the linear stage of wave growth, the enhanced pressure of the high-frequency part of the waves locally generates a ponderomotive force. This force acts on the plasma particles and redistributes them. Thus an additional electrostatic polarization field occurs, which influences the low-frequency part of the waves. Then, the low-frequency waves also cause a redistribution of the high-frequency waves. In the paper, a self-consistent system of equations is obtained, which describes the nonlinear interaction of the waves. It is shown that the considered mechanism of wave interaction causes a nonlinear stabilization of the high-frequency waves’ growth and a formation of local density structures of the charged particles. The density modifications of the charged particles during the non-linear stage of wave growth and the possible interval of aspect angles of the high-frequency waves are estimated. T3 - NLD Preprints - 52 Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14851 ER - TY - INPR A1 - Maaß, Peter A1 - Pereverzev, Sergei V. A1 - Ramlau, Ronny A1 - Solodky, Sergei G. T1 - An adaptive discretization for Tikhonov-Phillips regularization with a posteriori parameter selection N2 - The aim of this paper is to describe an efficient strategy for descritizing ill-posed linear operator equations of the first kind: we consider Tikhonov-Phillips-regularization χ^δ α = (a * a + α I)^-1 A * y ^δ with a finite dimensional approximation A n instead of A. We propose a sparse matrix structure which still leads to optimal convergences rates but requires substantially less scalar products for computing A n compared with standard methods. T3 - NLD Preprints - 48 Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14739 ER - TY - INPR A1 - Braun, Robert A1 - Feudel, Fred A1 - Guzdar, Parvez T1 - The route to chaos for a two-dimensional externally driven flow N2 - We have numerically studied the bifurcations and transition to chaos in a two-dimensional fluid for varying values of the Reynolds number. These investigations have been motivated by experiments in fluids, where an array of vortices was driven by an electromotive force. In these experiments, successive changes leading to a complex motion of the vortices, due to increased forcing, have been explored [Tabeling, Perrin, and Fauve, J. Fluid Mech. 213, 511 (1990)]. We model this experiment by means of two-dimensional Navier-Stokes equations with a special external forcing, driving a linear chain of eight counter-rotating vortices, imposing stress-free boundary conditions in the vertical direction and periodic boundary conditions in the horizontal direction. As the strength of the forcing or the Reynolds number is raised, the original stationary vortex array becomes unstable and a complex sequence of bifurcations is observed. Several steady states and periodic branches and a period doubling cascade appear on the route to chaos. For increasing values of the Reynolds number, shear flow develops, for which the spatial scale is large compared to the scale of the forcing. Furthermore, we have investigated the influence of the aspect ratio of the container as well as the effect of no-slip boundary conditions at the top and bottom, on the bifurcation scenario. T3 - NLD Preprints - 46 Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14717 ER - TY - INPR A1 - Lukaschewitsch, Michael T1 - Geoelectrical conductivity problems on unbounded domains N2 - This paper deals with the electrical conductivity problem in geophysics. It is formulated as an elliptic boundary value problem of second order for a large class of bounded and unbounded domains. A special boundary condition, the so called "Complete Electrode Model", is used. Poincaré inequalities are formulated and proved in the context of weighted Sobolev spaces, leading to existence and uniqueness statements for the boundary value problem. In addition, a parameter-to-solution operator arising from the inverse conductivity problem in medicine (EIT) and geophysics is investigated mathematically and is shown to be smooth and analytic. T3 - NLD Preprints - 45 Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14704 ER - TY - INPR A1 - Seehafer, Norbert A1 - Schumacher, Jörg T1 - Resistivity profile and instability of the plane sheet pinch N2 - The stability of the quiescent ground state of an incompressible, viscous and electrically conducting fluid sheet, bounded by stress-free parallel planes and driven by an external electric field tangential to the boundaries, is studied numerically. The electrical conductivity varies as cosh–2(x1/a), where x1 is the cross-sheet coordinate and a is the half width of a current layer centered about the midplane of the sheet. For a <~ 0.4L, where L is the distance between the boundary planes, the ground state is unstable to disturbances whose wavelengths parallel to the sheet lie between lower and upper bounds depending on the value of a and on the Hartmann number. Asymmetry of the configuration with respect to the midplane of the sheet, modelled by the addition of an externally imposed constant magnetic field to a symmetric equilibrium field, acts as a stabilizing factor. T3 - NLD Preprints - 44 Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14686 ER - TY - INPR A1 - Rüdiger, Sten A1 - Feudel, Fred A1 - Seehafer, Norbert T1 - Dynamo bifurcations in an array of driven convection-like rolls N2 - The bifurcations in a three-dimensional incompressible, electrically conducting fluid with an external forcing of the Roberts type have been studied numerically. The corresponding flow can serve as a model for the convection in the outer core of the Earth and is realized in an ongoing laboratory experiment aimed at demonstrating a dynamo effect. The symmetry group of the problem has been determined and special attention has been paid to symmetry breaking by the bifurcations. The nonmagnetic, steady Roberts flow loses stability to a steady magnetic state, which in turn is subject to secondary bifurcations. The secondary solution branches have been traced until they end up in chaotic states. T3 - NLD Preprints - 43 Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14678 ER -