TY - GEN A1 - Dolezalova, Barbora A1 - Kubatova, Brankica A1 - Kubat, Jiri A1 - Hamann, Wolf-Rainer T1 - The Quasi-WR Star HD 45166 Revisited T2 - Radiative signatures from the cosmos N2 - We studied the wind of the quasi Wolf-Rayet (qWR) star HD 45166. As a first step we modeled the observed UV spectra of this star by means of the state-of-the-art Potsdam Wolf-Rayet (PoWR) atmosphere code. We inferred the wind parameters and compared them with previous findings. Y1 - 2019 SN - 978-1-58381-925-8 SN - 1050-3390 VL - 519 SP - 197 EP - 200 PB - Astronomical soc pacific CY - San Fransisco ER - TY - GEN A1 - Grün, Eberhard A1 - de Pater, Imke A1 - Showalter, Mark A1 - Spahn, Frank A1 - Srama, Ralf T1 - Physics of dusty rings: History and perspective BT - Foreword T2 - Planetary and space science Y1 - 2006 U6 - https://doi.org/10.1016/j.pss.2006.05.005 SN - 0032-0633 VL - 54 IS - 9-10 SP - 837 EP - 843 PB - Elsevier CY - Oxford ER - TY - GEN A1 - Goychuk, Igor T1 - Comment on "Anomalous Escape Governed by Thermal 1/f Noise" Reply (R. K. Singh) T2 - Physical review letters Y1 - 2019 U6 - https://doi.org/10.1103/PhysRevLett.123.238902 SN - 0031-9007 SN - 1079-7114 VL - 123 IS - 23 PB - American Physical Society CY - College Park ER - TY - GEN A1 - Cestnik, Rok A1 - Abel, Markus T1 - Erratum: Inferring the dynamics of oscillatory systems using recurrent neural networks (Chaos : an interdisciplinary journal of nonlinear science. - 29 (2019) 063128) T2 - Chaos : an interdisciplinary journal of nonlinear science Y1 - 2019 U6 - https://doi.org/10.1063/1.5122803 SN - 1054-1500 SN - 1089-7682 VL - 29 IS - 8 PB - American Institute of Physics CY - Melville ER - TY - GEN A1 - Javanainen, Matti A1 - Martinez-Seara, Hector A1 - Metzler, Ralf A1 - Vattulainen, Ilpo Tapio T1 - Diffusion of Proteins and Lipids in Protein-Rich Membranesa T2 - Biophysical journal Y1 - 2018 U6 - https://doi.org/10.1016/j.bpj.2017.11.3009 SN - 0006-3495 SN - 1542-0086 VL - 114 IS - 3 SP - 551A EP - 551A PB - Cell Press CY - Cambridge ER - TY - GEN A1 - Gudowska-Nowak, Ewa A1 - Lindenberg, Katja A1 - Metzler, Ralf T1 - Preface: Marian Smoluchowski’s 1916 paper—a century of inspiration T2 - Journal of physics : A, Mathematical and theoretical Y1 - 2017 U6 - https://doi.org/10.1088/1751-8121/aa8529 SN - 1751-8113 SN - 1751-8121 VL - 50 IS - 38 PB - IOP Publ. Ltd. CY - Bristol ER - TY - GEN A1 - Parsons, R. D. A1 - Schüssler, F. A1 - Garrigoux, T. A1 - Balzer, A. A1 - Füssling, Matthias A1 - Hoischen, Clemens A1 - Holler, M. A1 - Mitchell, A. A1 - Pühlhofer, G. A1 - Rowell, G. A1 - Wagner, S. A1 - Bissaldi, E. A1 - Tam, P. H. T. T1 - The HESS II GRB Observation Scheme T2 - AIP conference proceedings / American Institute of Physics N2 - Gamma-ray bursts (GRBs) are some of the Universe’s most enigmatic and exotic events. However, at energies above 10 GeV their behaviour remains largely unknown. Although space based telescopes such as the Fermi-LAT have been able to detect GRBs in this energy range, their photon statistics are limited by the small detector size. Such limitations are not present in ground based gamma-ray telescopes such as the H.E.S.S. experiment, which has now entered its second phase with the addition of a large 600 m2 telescope to the centre of the array. Such a large telescope allows H.E.S.S. to access the sub 100-GeV energy range while still maintaining a large effective collection area, helping to potentially probe the short timescale emission of these events. We present a description of the H.E.S.S. GRB observation programme, summarising the performance of the rapid GRB repointing system and the conditions under which GRB observations are initiated. Additionally we will report on the GRB follow-ups made during the 2014-15 observation campaigns. Y1 - 2017 SN - 978-0-7354-1456-3 U6 - https://doi.org/10.1063/1.4968980 SN - 0094-243X SN - 1551-7616 VL - 1792 IS - 1 PB - American Institute of Physics CY - Melville ER - TY - GEN A1 - Angüner, Ekrem Oǧuzhan A1 - Aharonian, Felix A. A1 - Bordas, Pol A1 - Casanova, Sabrina A1 - Hoischen, Clemens A1 - Oya, I. A1 - Ziegler, A. T1 - HESS J1826-130 BT - a very hard gamma-Ray spectrum source in the Galactic Plane T2 - AIP conference proceedings / American Institute of Physics N2 - HESS J1826-130 is an unidentified hard spectrum source discovered by H.E.S.S. along the Galactic plane, the spectral index being Gamma = 1.6 with an exponential cut-off at about 12 TeV. While the source does not have a clear counterpart at longer wavelengths, the very hard spectrum emission at TeV energies implies that electrons or protons accelerated up to several hundreds of TeV are responsible for the emission. In the hadronic case, the VHE emission can be produced by runaway cosmic-rays colliding with the dense molecular clouds spatially coincident with the H.E.S.S. source. Y1 - 2017 SN - 978-0-7354-1456-3 U6 - https://doi.org/10.1063/1.4968928 SN - 0094-243X SN - 1551-7616 VL - 1792 IS - 1 PB - American Institute of Physics CY - Melville ER - TY - GEN A1 - Thoelert, Steffen A1 - Hörmann, Ulrich A1 - Antreich, Felix A1 - Meurer, Michael T1 - Ionospheric effects on high gain antenna GNSS measurements BT - TEC estimation and correction T2 - Proceedings of the 30th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2017) N2 - The ionospheric delay of global navigation satellite systems (GNSS) signals typically is compensated by adding a single correction value to the pseudorange measurement of a GNSS receiver. Yet, this neglects the dispersive nature of the ionosphere. In this context we analyze the ionospheric signal distortion beyond a constant delay. These effects become increasingly significant with the signal bandwidth and hence more important for new broadband navigation signals. Using measurements of the Galileo E5 signal, captured with a high gain antenna, we verify that the expected influence can indeed be observed and compensated. A new method to estimate the total electron content (TEC) from a single frequency high gain antenna measurement of a broadband GNSS signal is proposed and described in detail. The received signal is de facto unaffected by multi-path and interference because of the narrow aperture angle of the used antenna which should reduce the error source of the result in general. We would like to point out that such measurements are independent of code correlation, like in standard receiver applications. It is therefore also usable without knowledge of the signal coding. Results of the TEC estimation process are shown and discussed comparing to common TEC products like TEC maps and dual frequency receiver estimates. Y1 - 2017 U6 - https://doi.org/10.33012/2017.15343 SN - 2331-5911 SN - 2331-5954 SP - 3368 EP - 3374 PB - Instituite of Navigation CY - Washington ER - TY - GEN A1 - Metzler, Ralf T1 - Gaussianity Fair BT - the Riddle of Anomalous yet Non-Gaussian Diffusion T2 - Biophysical journal Y1 - 2017 U6 - https://doi.org/10.1016/j.bpj.2016.12.019 SN - 0006-3495 SN - 1542-0086 VL - 112 IS - 3 SP - 413 EP - 415 PB - Cell Press CY - Cambridge ER - TY - GEN A1 - Metzler, Ralf T1 - Anomalous Diffusion in Membranes and the Cytoplasm of Biological Cells T2 - Biophysical journal Y1 - 2017 U6 - https://doi.org/10.1016/j.bpj.2016.11.2577 SN - 0006-3495 SN - 1542-0086 VL - 112 IS - 3 SP - 476A EP - 476A PB - Cell Press CY - Cambridge ER - TY - GEN A1 - Lewandowsky, Stephan A1 - Cowtan, Kevin A1 - Risbey, James S. A1 - Mann, Michael E. A1 - Steinman, Byron A. A1 - Oreskes, Naomi A1 - Rahmstorf, Stefan T1 - Erratum: The 'pause' in global warming in historical context: II. Comparing models to observations (Environmental research letters. - Vol 13, (2018) 123007) T2 - Environmental research letters N2 - We review the evidence for a putative early 21st-century divergence between global mean surface temperature (GMST) and Coupled Model Intercomparison Project Phase 5 (CMIP5) projections. We provide a systematic comparison between temperatures and projections using historical versions of GMST products and historical versions of model projections that existed at the times when claims about a divergence were made. The comparisons are conducted with a variety of statistical techniques that correct for problems in previous work, including using continuous trends and a Monte Carlo approach to simulate internal variability. The results show that there is no robust statistical evidence for a divergence between models and observations. The impression of a divergence early in the 21st century was caused by various biases in model interpretation and in the observations, and was unsupported by robust statistics. Y1 - 2019 U6 - https://doi.org/10.1088/1748-9326/aafbb7 SN - 1748-9326 VL - 14 IS - 4 PB - IOP Publ. Ltd. CY - Bristol ER - TY - GEN A1 - Mawass, Mohamad-Assaad A1 - Arora, Ashima A1 - Sandig, Oliver A1 - Luo, Chen A1 - Unal, Ahmet A. A1 - Radu, Florin A1 - Valencia, Sergio A1 - Kronast, Florian T1 - Spatially resolved investigation of all optical magnetization switching in TbFe alloys T2 - 2018 IEEE International Magnetics Conference (INTERMAG) N2 - High storage density magnetic devices rely on the precise, reliable and ultrafast switching times of the magnetic states. Optical control of magnetization using femtosecond laser without applying any external magnetic field offers the advantage of switching magnetic states at ultrashort time scales, which has attracted a significant attention. Recently, it has been reported and demonstrated the,so-called, all-optical helicity-dependent switching (AO-HDS) in which a circularly polarized femtosecond laser pulse switches the magnetization of a ferromagnetic thin film as function of laser helicity [1]. Afterward, in more recent studies, it has been reported that AO-HDS is a general phenomenon existing in magnetic materials ranging from rare earth - transition metals ferrimagnetic (e.g. alloys, multilayers and hetero-structures system) to even ferromagnetic thin films. Among numerous studies in the literature which are discussing the microscopic origin of AO-HDS in ferromagnets or ferrimagnetic alloys, the most renowned concepts are momentum transfer via Inverse Faraday Effect (IFE) [1-3]and the concept of preferential thermal demagnetization for one magnetization direction by heating close to Tc (Curie temperature) in the presence of magnetic circular dichroism (MCD) [4-6]. In this study, we investigate all-optical magnetic switching using a stationary femtosecond laser spot (3-5 μm) in TbFe alloys via photoemission electron microscopy (PEEM) and x-ray magnetic circular dichroism (XMCD) with a spatial resolution of approximately 30 nm. We spatially characterize the effect of laser heating and local temperature profile created across the laser spot on AO-HDS in TbFe thin films. We find that AO-HDS occurs only in a `ring' shaped region surrounding the thermally demagnetized region formed by the laser spot and the formation of switched domains relies further on thermally induced domain wall motion. Our temperature dependent measurements highlight the importance of attainin... Y1 - 2018 SN - 978-1-5386-6425-4 U6 - https://doi.org/10.1109/INTMAG.2018.8508211 PB - IEEE CY - New York ER - TY - GEN A1 - Rychkov, Andrey A1 - Stojharov, Valery A1 - Kuznetsov, Alexey A1 - Rychkov, Dmitry T1 - The influence of recrystallization regimes on electret charge stability in low-density polyethylene films T2 - 2018 IEEE 2nd International Conference on Dielectrics (ICD) N2 - The electret state stability in nonpolar semicrystalline polymers is largely determined by the traps located at crystalline/ amorphous phase interfaces. Thus, the thermal history of such polymers should considerably influence their electret properties. In the present work, we investigate how recrystallization influences charge stability in low-density polyethylene corona electrets. It has been found that electret charge stability in quenched samples is higher than in slowly-crystallized ones. Phenomenologicaly, this can be explained by the increased number of deeper traps in samples with smaller crystallite size. KW - electrets KW - low-density polyethylene KW - crystallinity KW - quenching KW - recrystallization Y1 - 2018 SN - 978-1-5386-6389-9 SN - 978-1-5386-6388-2 SN - 978-1-5386-6390-5 U6 - https://doi.org/10.1109/ICD.2018.8514638 PB - IEEE CY - New York ER - TY - GEN A1 - Rastogi, Abhishake T1 - Tikhonov regularization with oversmoothing penalty for linear statistical inverse learning problems T2 - AIP Conference Proceedings : third international Conference of mathematical sciences (ICMS 2019) N2 - In this paper, we consider the linear ill-posed inverse problem with noisy data in the statistical learning setting. The Tikhonov regularization scheme in Hilbert scales is considered in the reproducing kernel Hilbert space framework to reconstruct the estimator from the random noisy data. We discuss the rates of convergence for the regularized solution under the prior assumptions and link condition. For regression functions with smoothness given in terms of source conditions the error bound can explicitly be established. KW - Statistical inverse problem KW - Tikhonov regularization KW - Hilbert Scales KW - Reproducing kernel Hilbert space KW - Minimax convergence rates Y1 - 2019 SN - 978-0-7354-1930-8 U6 - https://doi.org/10.1063/1.5136221 SN - 0094-243X VL - 2183 PB - American Institute of Physics CY - Melville ER - TY - GEN A1 - Stich, Michael A1 - Beta, Carsten T1 - Time-Delay Feedback Control of an Oscillatory Medium T2 - Biological Systems: Nonlinear Dynamics Approach N2 - The supercritical Hopf bifurcation is one of the simplest ways in which a stationary state of a nonlinear system can undergo a transition to stable self-sustained oscillations. At the bifurcation point, a small-amplitude limit cycle is born, which already at onset displays a finite frequency. If we consider a reaction-diffusion system that undergoes a supercritical Hopf bifurcation, its dynamics is described by the complex Ginzburg-Landau equation (CGLE). Here, we study such a system in the parameter regime where the CGLE shows spatio-temporal chaos. We review a type of time-delay feedback methods which is suitable to suppress chaos and replace it by other spatio-temporal solutions such as uniform oscillations, plane waves, standing waves, and the stationary state. Y1 - 2019 SN - 978-3-030-16585-7 SN - 978-3-030-16584-0 U6 - https://doi.org/10.1007/978-3-030-16585-7_1 SN - 2199-3041 SN - 2199-305X VL - 20 SP - 1 EP - 17 PB - Springer CY - Cham ER - TY - GEN A1 - Waldrip, Steven H. A1 - Niven, Robert K. A1 - Abel, Markus A1 - Schlegel, Michael T1 - Consistent maximum entropy representations of pipe flow networks T2 - AIP conference proceedings N2 - The maximum entropy method is used to predict flows on water distribution networks. This analysis extends the water distribution network formulation of Waldrip et al. (2016) Journal of Hydraulic Engineering (ASCE), by the use of a continuous relative entropy defined on a reduced parameter set. This reduction in the parameters that the entropy is defined over ensures consistency between different representations of the same network. The performance of the proposed reduced parameter method is demonstrated with a one-loop network case study. Y1 - 2017 SN - 978-0-7354-1527-0 U6 - https://doi.org/10.1063/1.4985365 SN - 0094-243X VL - 1853 IS - 1 PB - American Institute of Physics CY - Melville ER - TY - GEN A1 - Waldrip, Steven H. A1 - Niven, Robert K. A1 - Abel, Markus A1 - Schlegel, Michael T1 - Maximum entropy analysis of transport networks T2 - AIP conference proceedings N2 - The maximum entropy method is used to derive an alternative gravity model for a transport network. The proposed method builds on previous methods which assign the discrete value of a maximum entropy distribution to equal the traffic flow rate. The proposed method however, uses a distribution to represent each flow rate. The proposed method is shown to be able to handle uncertainty in a more elegant way and give similar results to traditional methods. It is able to incorporate more of the observed data through the entropy function, prior distribution and integration limits potentially allowing better inferences to be made. Y1 - 2017 SN - 978-0-7354-1527-0 U6 - https://doi.org/10.1063/1.4985364 SN - 0094-243X VL - 1853 IS - 1 PB - American Institute of Physics CY - Melville ER - TY - GEN A1 - Müller, Bernd Randolf A1 - Kupsch, Andreas A1 - Laquai, Rene A1 - Nellesen, Jens A1 - Tillmann, Wolfgang A1 - Kasperovich, Galina A1 - Bruno, Giovanni T1 - Microstructure Characterisation of Advanced Materials via 2D and 3D X-Ray Refraction Techniques T2 - Materials Science Forum N2 - 3D imaging techniques have an enormous potential to understand the microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this conference paper we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. We demonstrate showcases of ceramics and composite materials, where microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. We present in situ analysis of the damage evolution in an Al/Al2O3 metal matrix composite during tensile load and the identification of void formation (different kinds of defects, particularly unsintered powder hidden in pores, and small inhomogeneity’s like cracks) in Ti64 parts produced by selective laser melting using synchrotron X-ray refraction radiography and tomography. KW - X-ray refraction KW - radiography KW - tomography KW - synchrotron X-ray refraction radiography KW - CT KW - microscopy KW - creep KW - porosity KW - damage evolution KW - additive manufacturing KW - metal matrix composite Y1 - 2018 SN - 978-3-0357-1208-7 U6 - https://doi.org/10.4028/www.scientific.net/MSF.941.2401 SN - 0255-5476 VL - 941 SP - 2401 EP - 2406 PB - Trans Tech Publications Ltd CY - Zurich ER - TY - GEN A1 - Motter, Adilson E. A1 - Matias, Manuel A. A1 - Kurths, Jürgen A1 - Ott, Edward T1 - Dynamics on complex networks and applications T2 - Physica. D, Nonlinear phenomena KW - complex systems KW - nonlinear dynamics KW - statistical physics Y1 - 2006 U6 - https://doi.org/10.1016/j.physd.2006.09.012 SN - 0167-2789 VL - 224 IS - 1-2 SP - VII EP - VIII PB - Elsevier CY - Amsterdam ER -