17 research outputs found
Innovationen in der Hochschullehre: empirische Überprüfung eines Studienprogramms zur Verbesserung von vorlesungsbegleitenden Übungsgruppen in der Mathematik
Die Mathematikausbildung zukünftiger Haupt- und Realschullehrer/innen erscheint vor dem Hintergrund aktueller Befunde verbesserungswürdig. Ziel der vorliegenden Studie war es, lehr-lerntheoretisch und mathematikdidaktisch begründete Lehrinnovationen für den Übungsbetrieb im Fach Mathematik zu entwickeln und zu evaluieren. Die Lehrinnovationen setzen insbesondere an einer besseren fachspezifischen und didaktischen Ausbildung der Tutorinnen und Tutoren und einer stärker an Prinzipien der kognitiven Aktivierung orientierten Gestaltung der Übungsgruppen an. Es wurde eine quasi-experimentelle Studie zur Evaluation der Maßnahmen im Vergleich von zwei Kohorten durchgeführt. Die Ergebnisse zeigen, dass die Studierenden von den Lehrinnovationen profitierten; Unterstützungsqualität und Kompetenz der Tutorinnen und Tutoren wurden von der Experimentalgruppe als besser wahrgenommen. Außerdem wurden bessere Lösungen bei den semesterbegleitenden, zu Hause bearbeiteten Übungsaufgaben erreicht. Der Effekt schlug jedoch nicht auf die Leistung in der Abschlussklausur am Ende des Semesters durch. Als Folge der Lehrinnovationen empfanden sich die Studierenden zudem als weniger kompetent, was möglicherweise mit einer realistischeren Selbsteinschätzung zusammenhing.
04.11.2013 | Martin Hänze, Elisabeth Fischer (Kassel), Stephan Schreiber (Lüneburg), Rolf Biehler (Paderborn) & Reinhard Hochmuth (Lüneburg
Expression des Neuropeptid-Y-Gens im kardiovaskulaeren System
SIGLEAvailable from TIB Hannover: DW 6122 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Burst mode manipulation of magnonic vortex crystals
The manipulation of polarization states in 4×4 vortex crystals using sinusoidal magnetic field bursts is investigated by means of a broadband ferromagnetic-resonance setup. Magnetic field excitation with the proper amplitude and frequency allows tuning different polarization states, which are observed in the measured absorption spectra. The variation of the sinusoidal burst width consecutively identifies the time scale of the underlying process. A memorylike polarization state writing process is demonstrated on the submicrosecond time scale
Two body problem of core region coupled magnetic vortex stacks
The dynamics of all four combinations of possible polarity and circularity states in a stack of two vortices is investigated by time-resolved scanning transmission x-ray microscopy. The vortex stacks are excited by unidirectional magnetic fields leading to a collective oscillation. Four different modes are observed that depend on the relative polarizations and circularities of the stacks. They are excited to a driven oscillation. We observe a repulsive and attractive interaction of the vortex cores depending on their relative polarizations. The nonlinearity of this core interaction results in different trajectories that describe a two-body problem
Collective modes in three dimensional magnonic vortex crystals
Collective modes in three-dimensional crystals of stacked permalloy disks with magnetic vortices are investigated by ferromagnetic resonance spectroscopy and scanning transmission X-ray microscopy. The size of the arrangements is increased step by step to identify the different contributions to the interaction between the vortices. These contributions are the key requirement to understand complex dynamics of three dimensional vortex crystals. Both vertical and horizontal coupling determine the collective modes. In-plane dipoles strongly influence the interaction between the disks in the stacks and lead to polarity-dependent resonance frequencies. Weaker contributions discern arrangements with different polarities and circularities that result from the lateral coupling of the stacks and the interaction of the core regions inside a stack. All three contributions are identified in the experiments and are explained in a rigid particle model
Band structure engineering of two dimensional magnonic vortex crystals
Magnonic vortex crystals are studied via scanning transmission x-ray microscopy and ferromagnetic-resonance spectroscopy. We investigate a two-dimensional vortex crystal by imprinting waves with tunable wave vectors. The dispersion relation ω(k) is determined via ferromagnetic-resonance spectroscopy with a tunable frequency and wave vector for two vortex core polarization patterns that are adjusted by self-organized state formation prior to the measurement. We demonstrate that the band structure of the crystal is reprogrammed by tuning the vortex polarizations
Two-body problem of core-region coupled magnetic vortex stacks
The dynamics of all four combinations of possible polarity and circularity states in a stack of two vorticesis investigated by time-resolved scanning transmission x-ray microscopy. The vortex stacks are excited byunidirectional magnetic fields leading to a collective oscillation. Four different modes are observed that dependon the relative polarizations and circularities of the stacks. They are excited to a driven oscillation. We observe arepulsive and attractive interaction of the vortex cores depending on their relative polarizations. The nonlinearityof this core interaction results in different trajectories that describe a two-body problem
Collective modes in three-dimensional magnonic vortex crystals
Collective modes in three-dimensional crystals of stacked permalloy disks with magnetic vortices areinvestigated by ferromagnetic resonance spectroscopy and scanning transmission X-ray microscopy.The size of the arrangements is increased step by step to identify the different contributions to theinteraction between the vortices. These contributions are the key requirement to understand complexdynamics of three dimensional vortex crystals. Both vertical and horizontal coupling determine thecollective modes. In-plane dipoles strongly influence the interaction between the disks in the stacks andlead to polarity-dependent resonance frequencies. Weaker contributions discern arrangements withdifferent polarities and circularities that result from the lateral coupling of the stacks and the interactionof the core regions inside a stack. All three contributions are identified in the experiments and areexplained in a rigid particle model