TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Physikalische Zauberei : die Kette im Ring JF - In: Physik in unserer Zeit 45 (2014) 1, 44-45 N2 - Ein einfacher physikalischer Zaubertrick besteht darin, eine Kette über den Handrücken zu legen und danach von unten einen Ring über die Kette zu schieben. Der Ring kann entweder von der zweiten Hand oder der die Kette haltenden Hand gehalten werden. Er wird sodann losgelassen und soll (mit einem Knoten) in der Kette hängen bleiben. Y1 - 2014 U6 - https://doi.org/10.1002/piuz.201490004 SP - 44 EP - 45 ER - TY - JOUR A1 - Rotermund, H. H. A1 - Haas, G. A1 - Franz, Robert U. A1 - Tromp, R. M. A1 - Ertl, G. T1 - Imaging Pattern Formation in Surface Reactions from Ultrahigh Vacuum up to Atmospheric Pressures JF - In: Science 270 (1995) 5236, pp. 608-610 N2 - Two optical methods that allow pattern formation to be investigated at an arbitrary pressure are here applied to image concentration patterns of adsorbed species associated with heterogeneous catalytic reactions. In contrast to most surface physical techniques, these methods are not restricted to high vacuum conditions and thus bridge the “pressure gap.” With carbon monoxide oxidation on a (110) surface of platinum as an example, the coupling mechanisms responsible for spatiotemporal self-organization in surface reactions were followed from reaction-diffusion control to the thermokinetic region, associated with phenomena not previously observed in pattern formation. Y1 - 1995 U6 - https://doi.org/10.1126/science.270.5236.608 SP - 608 EP - 610 ER - TY - JOUR A1 - Rotermund, H. H. A1 - Haas, G. A1 - Franz, Robert U. A1 - Tromp, R. M. A1 - Ertl, G. T1 - Imaging pattern formation: bridging the pressure gap JF - In: Applied Physics A 61 (1995) 6, pp 569-574 N2 - Two surface-sensitive optical imaging methods, Ellipso-Microscopy for surface Imaging (EMSI) and Reflection Anisotropy Microscopy (RAM) are introduced. They allow imaging of pattern formation on surfaces, e.g., due to submonolayer coverages of adsorbates, at any arbitrary pressure. In spatio-temporal pattern formation during heterogeneously catalysed reactions this bridges the ‘pressure gap’ between well-defined UHV experiments and ‘real catalysis’. For the CO oxidation on Pt(110), the parameter space for pattern formation was extended up to 100 mbar, i.e., by 5 orders of magnitude compared to earlier investigations by Photo-Emission Electron Microscopy (PEEM) which had to be conducted below 10−3 mbar. With increasing pressure, the synchronisation mechanisms responsible for the observed pattern showed a gradual shift from reaction-diffusion to thermal-kinetic coupling unveiling previously unseen features of pattern formation in catalysis. Y1 - 1995 U6 - https://doi.org/10.1007/BF01542865 SP - 569 EP - 574 ER - TY - JOUR A1 - Ahlert, D. A1 - Franz, Robert U. A1 - Hohlwein, D. A1 - Prandl, W. A1 - Schiebel, P. A1 - Siemensmeyer, K. T1 - Die partielle Konversion von inkohärenter in kohärente Streuung an Protonen : das Ausfrieren der Quanten-Spin-Fluktuationen beim freien NH3-Rotator in Ni(NH3)6(PF6)2 JF - In: Zeitschrift für Kristallographie / Supplement issue No. 9 (1995) , p. 82 Y1 - 1995 SP - 82 ER - TY - JOUR A1 - Haas, G. A1 - Franz, Robert U. A1 - Rotermund, H. H. A1 - Tromp, R. M. A1 - Ertl, G. T1 - Imaging surface reactions with light JF - In: Surface Science Vol. 352–354 (1996), pp 1003–1006 N2 - Two new optical imaging methods with submonolayer surface sensitivity are applied together to investigate pattern formation of adsorbate concentrations on surfaces during heterogeneously catalysed reactions. Ellipso-microscopy for surface imaging (EMSI) is based on an ellipsometric effect, reflection anisotropy microscopy (RAM) on the polarising properties of surface anisotropies. For the CO oxidation reaction on a Pt(110) surface features like front propagation, target patterns and spiral waves are observed, similar as in prior investigations by photoemission electron microscopy (PEEM). By applying EMSI and RAM simultaneously and imaging the same spot of the surface, supplementary information is gained on the properties of the reaction diffusion fronts. When observing a reaction front by EMSI and RAM at temperatures between 330 and 420 K the image of the front in RAM trails behind its image in EMSI. EMSI seems to display changes in the coverage of adsorbates while RAM relates to variations in surface structure. Y1 - 1996 U6 - https://doi.org/10.1016/0039-6028(95)01316-4 SP - 1003 EP - 1006 ER - TY - CHAP A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Moisture detection at building walls using evaporative cooling T2 - In: InfraMation proceedings. - Vol. 14 (2013) Y1 - 2013 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Einfache Charakterisierung der zeitlichen und räumlichen Auflösung von Wärmebildkameras T2 - In: Temperatur 2013 : Fachtagung ; PTB Institut Berlin, 5./6. Juni 2013 ; [Verfahren und Geräte in der Temperatur- und Feuchtemesstechnik ; Tagungsband] / [Hrsg.: Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin]. Fachl. Mitträger: VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik (GMA), Fachgebiet 2.50: Temperatur und Feuchte. - Braunschweig [u.a.] : Physikalisch-Techn. Bundesanst., 2013. - ISBN 3-9810021-8-0 Y1 - 2013 SP - 137 EP - 142 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - The magic of the invisible: using IR imaging in physics education T2 - In: InfraMation proceedings / Infrared Training Center. - Vol. 14 (2013) Y1 - 2013 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Characterization of IR cameras in student labs JF - In: European journal of physics 34 (2013) 6, N2 - The content of a student lab course is described which deals with characterization of the most important parameters governing the performance of infrared cameras. In detail, the parameters describing the temperature resolution, spatial resolution and time resolution of commercial IR cameras are analysed using simple lab experiments. Understanding the respective performance of the system is the prerequisite for applying infrared thermal imaging to quantitative measurements in physics and technology. Y1 - 2013 U6 - https://doi.org/doi:10.1088/0143-0807/34/6/S73 SP - S73 EP - S90 ER - TY - JOUR A1 - Mangold, Klaus A1 - Shaw, Joseph A. A1 - Vollmer, Michael T1 - The physics of near-infrared photography JF - In: European journal of physics 34 (2013) 6, S51-S71 N2 - The physics behind the sometimes strange effects and 'unnatural' appearance of near-infrared (NIR) photographs is discussed in terms of reflection, absorption and transmission of NIR radiation with the respective objects. Besides discussing how NIR cameras work, several visible and NIR photograph pairs are presented, which include vegetation, natural water, clouds, the sky, and humans. In addition, some physics-oriented experimental NIR images are presented which clearly demonstrate some of the basic physics behind some of these awesome sights. Y1 - 2013 U6 - https://doi.org/doi:10.1088/0143-0807/34/6/S51 SP - S51 EP - S71 ER -