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Seminars

Tuesday, 10.12.2019 10:00

Bei Yi Zhu (National Lab for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing, China)

Abstract: We study the vortex ratchet effects in superconducting asymmetric curved bridges. By transport measurements, we find that the rectified dc voltages are significantly enhanced, and we obtain clearly asymmetric voltage waveforms versus time in one period. The rectification effect can be achieved in a very wide range of temperatures, currents and magnetic fields. Based on the simulations of time-dependent Ginzburg-Landau equations, we demonstrate that the giant ratchet effects are mainly caused by the collective behavior of vortices in this asymmetric structure, which is quite...

Thursday, 12.12.2019 15:00

Jan Fábry (Fyzikální ústav AV ČR, oddělení dielektrik)

Abstract: The discussed Wentzel Jamnitzer’s work belongs to works which have been published most frequently throughout the 15-th and 16-th centuries and which depicted Platonic (regular) bodies. It was believed at that time that these bodies comprised the essence of nature of the surrounding world, which was percepted by external senses, or exclusively accessible by intellect. Complexity of the surrounding world could be symbolized by a geometric combination of the Platonic bodies which gave rise to semiregular or even more complicated bodies.