@article{GuliakovaGorokhovatskyGalikhanovetal.2019,
  author    = {Guliakova, A. A. and Gorokhovatsky, Yu. A. and Galikhanov, M. F. and Fr{\"u}bing, Peter},
  title     = {Thermoactivational spectroscopy of the high impact polystyrene based composite films},
  series = {St. Petersburg Polytechnic University Journal : Physics and Mathematics},
  volume    = {12},
  journal   = {St. Petersburg Polytechnic University Journal : Physics and Mathematics},
  number    = {4},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2405-7223},
  doi       = {10.18721/JPM.12401},
  pages     = {9 -- 16},
  year      = {2019},
  abstract  = {The relaxation processes in the high impact polystyrene (HIPS) films filled with 2, 4, 6 vol.\% of titanium dioxide (TiO2) of the rutile modification have been studied using the thermally stimulated depolarization current (TSDC) technique. Three relaxation processes were observed in the composite HIPS films. The first one (a-relaxation peak) appeared at about 93 degrees C and represented the glass transition. The second peak p was a high-temperature part of the first one and overlapped it. The p peak was caused by the release and subsequent motion of excess charges deposited during the electret preparation or the polarization process. The third peak appeared at about 150 degrees C and occurred only in the spectra of the composite films. The overlapping peaks were separated by the thermal cleaning technique. The subsequent application of the numerical methods (the Tikhonov regularization technique) allowed to determine the activation energy of the second process and to compare the obtained value with the corresponding data on the dielectric relaxation.},
  language  = {ru}
}
@article{Daute1995,
  author    = {Daute, Daniela},
  title     = {{\"U}bermolekulare Strukturbildung durch Selbstorganisation neuer discoider Arylaminotriazine and assoziierter Alkoxybenzoate},
  year      = {1995},
  language  = {de}
}
@misc{Fischer2012,
  type      = {Master Thesis},
  author    = {Fischer, Jost},
  title     = {{\"U}ber Synchronisationsph{\"a}nomene nichtlinearer akustischer Oszillatoren},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-63618},
  school      = {Universit{\"a}t Potsdam},
  year      = {2012},
  abstract  = {In dieser Arbeit werden die Effekte der Synchronisation nichtlinearer, akustischer Oszillatoren am Beispiel zweier Orgelpfeifen untersucht. Aus vorhandenen, experimentellen Messdaten werden die typischen Merkmale der Synchronisation extrahiert und dargestellt. Es folgt eine detaillierte Analyse der {\"U}bergangsbereiche in das Synchronisationsplateau, der Ph{\"a}nomene w{\"a}hrend der Synchronisation, als auch das Austreten aus der Synchronisationsregion beider Orgelpfeifen, bei verschiedenen Kopplungsst{\"a}rken. Die experimentellen Befunde werfen Fragestellungen nach der Kopplungsfunktion auf. Dazu wird die Tonentstehung in einer Orgelpfeife untersucht. Mit Hilfe von numerischen Simulationen der Tonentstehung wird der Frage nachgegangen, welche fluiddynamischen und aero-akustischen Ursachen die Tonentstehung in der Orgelpfeife hat und inwiefern sich die Mechanismen auf das Modell eines selbsterregten akustischen Oszillators abbilden l{\"a}sst. Mit der Methode des Coarse Graining wird ein Modellansatz formuliert.},
  language  = {de}
}
@phdthesis{Hertzsch1996,
  author    = {Hertzsch, Jan-Martin},
  title     = {{\"U}ber nichtelastische Kollisionen und ihren Einfluß auf die Strukturbildung in planetaren Ringen},
  pages     = {87 S., Ill.},
  year      = {1996},
  language  = {de}
}
@phdthesis{Rettig2016,
  author    = {Rettig, Robert},
  title     = {{\"U}ber die Anisotropie der Kosmischen Strahlung},
  school      = {Universit{\"a}t Potsdam},
  pages     = {90, XV},
  year      = {2016},
  language  = {de}
}
@phdthesis{Schollmeyer2002,
  author    = {Schollmeyer, Hauke},
  title     = {Zweidimensionale molekulare Ordnung und Strukturbildung : Triakontan an planaren SiO2/Luft-Grenzfl{\"a}chen},
  pages     = {130 S.},
  year      = {2002},
  language  = {de}
}
@phdthesis{Liepertz2017,
  author    = {Liepertz, Sven Christian},
  title     = {Zusammenhang zwischen dem Professionswissen von Physiklehrkr{\"a}ften, dem sachstrukturellen Angebot des Unterrichts und der Sch{\"u}lerleistung},
  series = {Studien zum Physik- und Chemielernen ; 224},
  journal   = {Studien zum Physik- und Chemielernen ; 224},
  publisher = {Logos},
  address   = {Berlin},
  isbn      = {978-3-8325-4480-5},
  school      = {Universit{\"a}t Potsdam},
  pages     = {133},
  year      = {2017},
  language  = {de}
}
@article{Mikelskis1993,
  author    = {Mikelskis, Helmut},
  title     = {Zur {\"O}kologisierung des Lernprozesses : Versuch {\"u}ber einen vernachl{\"a}ssigten Aspekt von Umweltbildung},
  isbn      = {3-89088-073-8},
  year      = {1993},
  language  = {de}
}
@phdthesis{Pedzisz1993,
  author    = {Pedzisz, Bozena},
  title     = {Zur Rolle historischer Betrachtungen im Physikunterricht unter besonderer Ber{\"u}cksichtigung grundlegender Experimente},
  pages     = {3, 167,73 Bl. : Ill.},
  year      = {1993},
  language  = {de}
}
@article{Starauschek2006,
  author    = {Starauschek, Erich},
  title     = {Zur Rolle der Sprache beim Lernen von Physik},
  isbn      = {3-589-22148-8},
  year      = {2006},
  language  = {de}
}
@phdthesis{Krey2011,
  author    = {Krey, Olaf},
  title     = {Zur Rolle der Mathematik in der Physik : Wissenschaftstheoretische Aspekte und Vorstellungen Physiklernender},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59412},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {Mathematik spielt im Physikunterricht eine nicht unerhebliche Rolle - wenn auch eine zwiesp{\"a}ltige. Oft wird sie sogar zum Hindernis beim Lernen von Physik und kann ihr emanzipatorisches Potenzial nicht entfalten. Die vorliegende Arbeit stellt zwei Bausteine f{\"u}r eine begr{\"u}ndete Konzeption zum Umgang mit Mathematik beim Lernen von Physik zur Verf{\"u}gung. Im Theorieteil der Arbeit werden zum Einen wissenschaftstheoretische Aspekte der Rolle der Mathematik in der Physik aufgearbeitet und der physikdidaktischen Forschungsgemeinschaft im Zusammenhang zug{\"a}nglich gemacht. Zum anderen werden Forschungsergebnisse zu Vorstellungen Lernender {\"u}ber Physik und Mathematik sowie im Bereich der Epistemologie zusammengestellt. Im empirischen Teil der Arbeit werden Vorstellungen zur Rolle der Mathematik in der Physik von Sch{\"u}lerinnen und Sch{\"u}lern der Klassenstufen 10 und 12 sowie Physik-Lehramtstudierenden im Grundstudium mit Hilfe eines Fragebogens erhoben und unter Verwendung inhaltsanalytischer bzw. statistischer Methoden ausgewertet. Die Ergebnisse zeigen unter Anderem, dass Mathematik im Physikunterricht entgegen g{\"a}ngiger Meinungen bei den Lernenden nicht negativ, aber zumindest bei j{\"u}ngeren Lernenden formal und algorithmisch konnotiert ist.},
  language  = {de}
}
@phdthesis{Meister1995,
  author    = {Meister, Claudia-Veronika},
  title     = {Zur physikalischen Theorie f{\"u}r Plasmen im Nichtgleichgewicht},
  pages     = {228 S.},
  year      = {1995},
  language  = {de}
}
@phdthesis{Carroll2004,
  author    = {Carroll, Thorsten Anthony},
  title     = {Zur Linienentstehung und Diagnostik in kleinskaligen Magnetfeldern der solaren Photosph{\"a}re},
  pages     = {111 S.},
  year      = {2004},
  language  = {de}
}
@article{FruhnerCzichocki1996,
  author    = {Fruhner, Horst and Czichocki, G.},
  title     = {Zur Bestimmung der kritischen Mizellkonzentration (CMC)},
  year      = {1996},
  language  = {de}
}
@phdthesis{Fortmann2003,
  author    = {Fortmann, Martin},
  title     = {Zum Einfluß tropodh{\"a}rischer Aerosole auf das Klima der Arktis},
  pages     = {144 S.},
  year      = {2003},
  language  = {de}
}
@phdthesis{Gellert2004,
  author    = {Gellert, Marcus},
  title     = {Zum Dynamoeffekt in extern getriebenen Str{\"o}mungen},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001705},
  school      = {Universit{\"a}t Potsdam},
  year      = {2004},
  abstract  = {Die Frage nach der Herkunft und der dynamischen Entwicklung langlebiger kosmischer Magnetfelder ist in vielen Details noch unbeantwortet. Es besteht zwar kein Zweifel daran, dass das Magnetfeld der Erde und anderer kosmischer Objekte durch den sogenannten Dynamoeffekt verursacht werden, der genaue Mechanismus als auch die notwendigen Voraussetzungen und Randbedingungen der zugrundeliegenden Str{\"o}mungen sind aber weitgehend unbekannt. Die f{\"u}r einen Dynamo interessanten Str{\"o}mungsmuster, die im Inneren von Himmelsk{\"o}rpern durch Konvektion und differentielle Rotation entstehen, sind Konvektionsrollen parallel zur Rotationsachse. Auf einer Str{\"o}mung mit eben solcher Geometrie, der sogenannten Roberts-Str{\"o}mung, basieren die in der vorliegenden Arbeit untersuchten Dynamomodelle. Mit Methoden der nichtlinearen Dynamik wird versucht, das Systemverhalten bei {\"A}nderung der Systemparamter genauer zu charakterisieren. Die numerischen Untersuchungen beginnen mit einer Analyse der Dynamoaktivit{\"a}t der Roberts-Str{\"o}mung in Abh{\"a}ngigkeit von den zwei freien Parametern in den Modellgleichungen, der magnetischen Prandtl-Zahl und der St{\"a}rke des Energieinputs. Gefunden werden verschiedene L{\"o}sungstypen die von einem station{\"a}ren Magnetfeld {\"u}ber periodische bis zu chaotischen Zust{\"a}nden reichen. Die yugrundeliegenden Symmetrien werden beschrieben und die Bifurkationen, die zum Wechsel der L{\"o}sungstypen f{\"u}hren, charakterisiert. Zus{\"a}tzlich gibt es Bereiche bei sehr kleinen Prandtl-Zahlen, in denen {\"u}berhaupt kein Dynamo existiert. Dieses Verhalten wird in der Literatur auch f{\"u}r viele andere numerisch ausgewertete Modelle beschrieben. Im {\"U}bergangsbereich zwischen dynamoaktivem und dynamoinaktivem Bereich wird das Auftreten einer sogenannten Blowout-Bifurkation gefunden. Desweiteren besch{\"a}ftigt sich die Arbeit mit der Frage, inwiefern Helizit{\"a}t, also eine schraubenf{\"o}rmige Bewegung, der Str{\"o}mung den Dynamoeffekt beeinflusst. Dazu werden {\"a}hnliche Str{\"o}mungstypen verglichen, die sich haupts{\"a}chlich in ihrem Helizit{\"a}tswert unterscheiden. Es wird gefunden, dass ein bestimmter Wert der Helizit{\"a}t nicht unterschritten werden darf, um einen stabilen Roberts-Dynamo zu erhalten.},
  language  = {de}
}
@article{Mikelskis1993,
  author    = {Mikelskis, Helmut},
  title     = {Zukunftsperspektiven physikdidaktischer Forschung im vereinigten Deutschland},
  isbn      = {3-88064-223-0},
  year      = {1993},
  language  = {de}
}
@article{Mikelskis2001,
  author    = {Mikelskis, Helmut},
  title     = {Zukunftsperspektiven der Bildung im Informationszeitalter und in der Wissensgesellschaft},
  year      = {2001},
  language  = {de}
}
@article{TrollBeimGraben1998,
  author    = {Troll, G{\"u}nter and Beim Graben, Peter},
  title     = {Zipfs law is not a consequence of the central limit theorem},
  year      = {1998},
  language  = {en}
}
@article{BlasiusToenjes2009,
  author    = {Blasius, Bernd and Toenjes, Ralf},
  title     = {Zipf's Law in the popularity distribution of chess openings},
  issn      = {0031-9007},
  doi       = {10.1103/Physrevlett.103.218701},
  year      = {2009},
  abstract  = {We perform a quantitative analysis of extensive chess databases and show that the frequencies of opening moves are distributed according to a power law with an exponent that increases linearly with the game depth, whereas the pooled distribution of all opening weights follows Zipf's law with universal exponent. We propose a simple stochastic process that is able to capture the observed playing statistics and show that the Zipf law arises from the self-similar nature of the game tree of chess. Thus, in the case of hierarchical fragmentation the scaling is truly universal and independent of a particular generating mechanism. Our findings are of relevance in general processes with composite decisions.},
  language  = {en}
}
@article{LangeReiterKniepertetal.2015,
  author    = {Lange, Ilja and Reiter, Sina and Kniepert, Juliane and Piersimoni, Fortunato and Paetzel, Michael and Hildebrandt, Jana and Brenner, Thomas J. K. and Hecht, Stefan and Neher, Dieter},
  title     = {Zinc oxide modified with benzylphosphonic acids as transparent electrodes in regular and inverted organic solar cell structures},
  series = {Applied physics letters},
  volume    = {106},
  journal   = {Applied physics letters},
  number    = {11},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0003-6951},
  doi       = {10.1063/1.4916182},
  pages     = {5},
  year      = {2015},
  abstract  = {An approach is presented to modify the work function of solution-processed sol-gel derived zinc oxide (ZnO) over an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using poly(3-hexylthiophene): phenyl-C71-butyric acid methyl ester as the active layer. These devices compete with or even surpass the performance of the reference on indium tin oxide/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Our findings highlight the potential of properly modified ZnO as electron or hole extracting electrodes in hybrid optoelectronic devices. (C) 2015 AIP Publishing LLC.},
  language  = {en}
}
@article{RosenhahnFinlayPettitetal.2009,
  author    = {Rosenhahn, Axel and Finlay, John A. and Pettit, Michala E. and Ward, Andy and Wirges, Werner and Gerhard, Reimund and Callow, Maureen E. and Grunze, Michael and Callow, James A.},
  title     = {Zeta potential of motile spores of the green alga Ulva linza and the influence of electrostatic interactions on spore settlement and adhesion strength},
  issn      = {1559-4106},
  doi       = {10.1116/1.3110182},
  year      = {2009},
  abstract  = {The zeta potential of the motile spores of the green alga (seaweed) Ulva linza was quantified by video microscopy in combination with optical tweezers and determined to be -19.3{\~n}1.1 mV. The electrostatic component involved in the settlement and adhesion of spores was studied using electret surfaces consisting of PTFE and bearing different net charges. As the surface chemistry remains the same for differently charged surfaces, the experimental results isolate the influence of surface charge and thus electrostatic interactions. Ulva spores were demonstrated to have a reduced tendency to settle on negatively charged surfaces and when they did settle the adhesion strength of settled spores was lower than with neutral or positively charged surfaces. These observations can be ascribed to electrostatic interactions.},
  language  = {en}
}
@article{MellingerFloresSuarezSinghetal.2007,
  author    = {Mellinger, Axel and Flores Su{\´a}rez, Rosaura and Singh, Rajeev and Wegener, Michael and Wirges, Werner and Gerhard, Reimund},
  title     = {Zerst{\"o}rungsfreie Tomographie von Raumladungs- und Polarisationsverteilungen mittles W{\"a}rmepulsen},
  issn      = {0171-8096},
  doi       = {10.1524/teme.2007.74.9.437},
  year      = {2007},
  abstract  = {Non-destructive, three-dimensional imaging of space-charge and polarization distributions in electret materials has been implemented by means of laser-induced thermal pulses. In pyroelectric films of poled poly(vinylidene fluoride), images of up to 45 x 45 pixels with a depth resolution of less than 0.5 mu m and a lateral resolution of 40 mu m were recorded, the latter being limited by fast thermal diffusion in the absorbing metallic front electrode. Initial applications include the analysis of polarization distributions in corona-poled piezoelectric sensor cables and the detection of patterned space-charge distributions in polytetrafluoroethylene films.},
  language  = {de}
}
@book{Beta2008,
  author    = {Beta, Carsten},
  title     = {Zelldynamik aus Sicht der Strukturbildung : physikalische Konzepte f{\"u}r ein biologisches Problem : Antrittsvorlesung 2008-06-05},
  publisher = {Univ.-Bibl.},
  address   = {Potsdam},
  year      = {2008},
  abstract  = {Was lebt ist in Bewegung. Diese einfache Assoziation gilt nicht nur f{\"u}r ausgewachsene Organismen, sondern auch f{\"u}r einzelne Zellen, die kleinsten lebenden Bausteine der Natur. Die Beweglichkeit von Zellen spielt eine zentrale Rolle bei einer Vielzahl biologischer Vorg{\"a}nge, wie zum Beispiel der Embryonalentwicklung, der Heilung von Wunden oder der krankhaften Ausbreitung von Krebszellen im K{\"o}rper. Am Beispiel der Beweglichkeit einer einfachen Am{\"o}be k{\"o}nnen grundlegende Mechanismen der Zelldynamik untersucht und auf der Grundlage physikalischer Konzepte erkl{\"a}rt werden.},
  language  = {de}
}
@phdthesis{Schwarz1994,
  author    = {Schwarz, Udo},
  title     = {Zeitreihenanalyse astrophysikalischer Aktivit{\"a}tsph{\"a}nomene},
  pages     = {IV, 149 S.},
  year      = {1994},
  language  = {de}
}
@phdthesis{Kopf2008,
  author    = {Kopf, Markus},
  title     = {Zeeman-Doppler Imaging of active late-type stars},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-37387},
  school      = {Universit{\"a}t Potsdam},
  year      = {2008},
  abstract  = {Stellare Magnetfelder spielen eine wichtige Rolle bei der Entstehung und Entwicklung von Sternen. Leider entziehen sie sich aber, aufgrund ihrer großen Entfernung zur Erde, einer direkten Beobachtung. Dies gilt zumindest f{\"u}r derzeitige und in naher Zukunft zur Verf{\"u}gung stehende Instrumente. Um aber beispielsweise zu verstehen, ob Magnetfelder durch einen Dynamoprozess generiert werden oder {\"U}berbleibsel der Sternentstehung sind, ist es zwingend erforderlich, die Oberfl{\"a}chenstruktur und die zeitliche Entwicklung von stellaren Feldern zu untersuchen. Gl{\"u}cklicherweise haben wir mit der Dopplerverschiebung sowie der Polarisation von Licht Mittel zur Verf{\"u}gung, um indirekt die Magnetfeldtopologie entfernter Sternen zu rekonstruieren, wenn auch nur die schnell rotierender. Die auf den beiden genannten Effekten basierende Rekonstruktionsmethode ist unter dem Namen Zeeman-Doppler Imaging (ZDI) bekannt. Sie stellt eine leistungsf{\"a}hige Methode dar, um aus rotationsverbreiterten Stokes Profilen schnell rotierender Sterne Oberfl{\"a}chenkartierungen der Temperatur und Magnetfeldverteilung zu erstellen. Durch das ZDI konnten in den vergangenen Jahren die Magnetfeldverteilungen zahlreicher Sterne rekonstruiert werden. Diese Methode stellt allerdings sehr hohe Anforderungen sowohl an die Instrumentierung als auch an die Rechenleistung und ist deshalb h{\"a}ufig mit zahlreichen Annahmen und N{\"a}herungen verbunden. Ziel dieser Arbeit war es, Methoden f{\"u}r ein ZDI zu entwickeln, das darauf ausgelegt ist, zeitaufgel{\"o}ste spektropolarimetrische Daten von aktiven sp{\"a}ten Sternen zu invertieren. Es sollte also insbesondere den komplexen und lokalen Magnetfeldstrukturen dieser Sterne Rechnung getragen werden. Um die Orientierung und St{\"a}rke solcher Felder zuverl{\"a}ssig rekonstruieren zu k{\"o}nnen, sollte die Inversion im Stande sein, alle vier Stokes-Komponenten einzubeziehen. Ferner war vorgesehen auf vollst{\"a}ndigen polarisierten Strahlungstransportmodellierungen aufzubauen. Dies erm{\"o}glicht eine simultane und selbstkonsistente Temperatur- und Magnetfeld-Inversion, die damit dem komplexen Zusammenspiel zwischen Temperatur und Magnetfeld gerecht wird. Schließlich sollte die Anwendung eines neu zu entwickelnden ZDI Programms auf Stokes I und V Beobachtungen von II Pegasi (kurz: II Peg) erste Magnefeldkarten dieses sehr aktiven Sterns liefern. Um den hohen Rechenaufwand, der mit der Inversionsmethode einhergeht, besser bew{\"a}ltigen zu k{\"o}nnen, wurde zun{\"a}chst eine schnelle Approximationsmethode f{\"u}r den polarisierten Strahlungstransport entwickelt. Sie basiert auf einer Hauptkomponentenanalyse (PCA) sowie auf k{\"u}nstlichen Neuronalen Netzen. Letztere approximieren den funktionalen Zusammenhang zwischen atmosph{\"a}rischen Parametern und den zugeh{\"o}rigen lokalen Stokes Profilen. Inverse Probleme sind potentiell schlecht gestellt und erfordern in der Regel eine Regularisierung. Der entwickelte Ansatz verwendet eine lokale Entropie, die auf die Besonderheiten bei der Rekonstruktion lokalisierter Magnetfeder eingeht. Ein weiterer neuartiger Ansatz befasst sich mit der Rauschreduktion polarimetrischer Beobachtungsdaten. Er macht sich die Hauptkomponentenanalyse zu Nutze, um mit Hilfe einer Vielzahl beobachteter Spektrallinien, einzelne Linien mit drastisch vergr{\"o}ßertem Signal-zu-Rausch-Verh{\"a}ltnis wieder zu geben. Diese Methode hat gegen{\"u}ber anderen Multi-Spektrallinien-Verfahren den Vorteil, nach wie vor eine Inversion auf der Basis einzelner Spektrallinien durchf{\"u}hren zu k{\"o}nnen. Schließlich wurde das Inversionsprogramm iMap entwickelt, das die zuvor genannten Methoden implementiert. Detaillierte Testrechnungen demonstrieren die Funktionsf{\"a}higkeit und Genauigkeit der schnellen Synthese-Methode und weisen einen Zeitgewinn von nahezu drei Gr{\"o}ßenordnungen gegen{\"u}ber der konventionellen Strahlungstransportberechnung auf. Desweiteren untersuchen wir den Einfluss der verschiedenen Stokes Komponenten (IV bzw. IVQU) auf die Zuverl{\"a}ssigkeit, ein bekanntes Magnetfeld zu rekonstruieren. Damit belegen wir die Zuverl{\"a}ssigkeit unseres Inversionsprogrammes und zeigen dar{\"u}ber hinaus auch Einschr{\"a}nkungen von Magnetfeldinversionen im allgemeinen auf. Eine erste Inversion von Stokes I und V Profilen von II Peg liefert zum ersten Mal f{\"u}r diesen Stern simultan Temperatur- und Magnetfeldverteilungen.},
  language  = {en}
}
@article{CioniBekkiGirardietal.2016,
  author    = {Cioni, Maria-Rosa L. and Bekki, Kenji and Girardi, Leo and de Grijs, Richard and Irwin, Mike J. and Ivanov, Valentin D. and Marconi, Marcella and Oliveira, Joana M. and Piatti, Andres E. and Ripepi, Vincenzo and van Loon, Jacco Th.},
  title     = {XVII. Proper motions of the Small Magellanic Cloud and the Milky Way globular cluster 47 Tucanae},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {586},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201527004},
  pages     = {67 -- 75},
  year      = {2016},
  abstract  = {Aims. In this study we use multi-epoch near-infrared observations from the VISTA survey of the Magellanic Cloud system (VMC) to measure the proper motions of different stellar populations in a tile of 1.5 deg2 in size in the direction of the Galactic globular cluster 47 Tuc. We obtain the proper motion of the cluster itself, of the Small Magellanic Cloud (SMC), and of the field Milky Way stars. Methods. Stars of the three main stellar components are selected according to their spatial distributions and their distributions in colour\&\#8722;magnitude diagrams. Their average coordinate displacement is computed from the difference between multiple Ks-band observations for stars as faint as Ks = 19 mag. Proper motions are derived from the slope of the best-fitting line among ten VMC epochs over a time baseline of ~1 yr. Background galaxies are used to calibrate the absolute astrometric reference frame. Results. The resulting absolute proper motion of 47 Tuc is (\&\#956;\&\#945;cos(\&\#948;), \&\#956;\&\#948;) = (+7.26 ± 0.03, \&\#8722;1.25 ± 0.03) mas yr-1. This measurement refers to about 35 000 sources distributed between 10\&\#8242; and 60\&\#8242; from the cluster centre. For the SMC we obtain (\&\#956;\&\#945;cos(\&\#948;), \&\#956;\&\#948;) = (+1.16 ± 0.07, \&\#8722;0.81 ± 0.07) mas yr-1 from about 5250 red clump and red giant branch stars. The absolute proper motion of the Milky Way population in the line of sight (l = 305.9, b = \&\#8722;44.9) of this VISTA tile is (\&\#956;\&\#945;cos(\&\#948;), \&\#956;\&\#948;) = (+10.22 ± 0.14, \&\#8722;1.27 ± 0.12) mas yr-1 and has been calculated from about 4000 sources. Systematic uncertainties associated with the astrometric reference system are 0.18 mas yr-1. Thanks to the proper motion we detect 47 Tuc stars beyond its tidal radius.},
  language  = {en}
}
@article{SanjurjoFerrrinTorrejonPostnovetal.2017,
  author    = {Sanjurjo-Ferrrin, G. and Torrejon, J. M. and Postnov, K. and Oskinova, Lida and Rodes-Roca, J. J. and Bernabeu, Guillermo},
  title     = {XMM-Newton spectroscopy of the accreting magnetar candidate 4U0114+65},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {606},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201630119},
  pages     = {4039 -- 4042},
  year      = {2017},
  abstract  = {Methods. We analysed the energy-resolved light curve and the time-resolved X-ray spectra provided by the EPIC cameras on board XMM-Newton. We also analysed the first high-resolution spectrum of this source provided by the Reflection Grating Spectrometer. Results. An X-ray pulse of 9350 +/- 160 s was measured. Comparison with previous measurements confirms the secular spin up of this source. We successfully fit the pulse-phase-resolved spectra with Comptonisation models. These models imply a very small (r similar to 3 km) and hot (kT similar to 2-3 keV) emitting region and therefore point to a hot spot over the neutron star (NS) surface as the most reliable explanation for the X-ray pulse. The long NS spin period, the spin-up rate, and persistent X-ray emission can be explained within the theory of quasi-spherical settling accretion, which may indicate that the magnetic field is in the magnetar range. Thus, 4U0114+65 could be a wind-accreting magnetar. We also observed two episodes of low luminosity. The first was only observed in the low-energy light curve and can be explained as an absorption by a large over-dense structure in the wind of the B1 supergiant donor. The second episode, which was deeper and affected all energies, may be due to temporal cessation of accretion onto one magnetic pole caused by non-spherical matter capture from the structured stellar wind. The light curve displays two types of dips that are clearly seen during the high-flux intervals. The short dips, with durations of tens of seconds, are produced through absorption by wind clumps. The long dips, in turn, seem to be associated with the rarefied interclump medium. From the analysis of the X-ray spectra, we found evidence of emission lines in the X-ray photoionised wind of the B1Ia donor. The Fe K alpha line was found to be highly variable and much weaker than in other X-ray binaries with supergiant donors. The degree of wind clumping, measured through the covering fraction, was found to be much lower than in supergiant donor stars with earlier spectral types. Conclusions. The XMM-Newton spectroscopy provided further support for the magnetar nature of the neutron star in 4U0114+65. The light curve presents dips that can be associated with clumps and the interclump medium in the stellar wind of the mass donor.},
  language  = {en}
}
@article{IgnaceOskinovaBrown2003,
  author    = {Ignace, Richard and Oskinova, Lida and Brown, John C.},
  title     = {XMM-Newton Observations of the Nitrogen-Rich Wolf-Rayet star WR1},
  year      = {2003},
  abstract  = {We present XMM-Newton results for the X-ray spectrum from the N-rich Wolf-Rayet (WR) star WR 1. The EPIC instrument was used to obtain a medium-resolution spectrum. The following features characterize this spectrum: (a) significant emission "bumps" appear that are coincident with the wavelengths of typical strong lines, such as Mg XI, Si XIII and S XV; (b) little emission is detected above 4 keV, in contrast to recent reports of a hard component in the stars WR 6 and WR 110 which are of similar subtype; and (c) evidence for sulfur K-edge absorption at about 2.6 keV, which could only arise from absorption of X-rays by the ambient stellar wind. The lack of hard emission in our dataset is suggestive that WR 1 may truly be a single star, thus representing the first detailed X-ray spectrum that isolates the WR wind alone (in contrast to colliding wind zones). Although the properties of the S-edge are not well-constrained by our data, it does appear to be real, and its detection indicates that at least some of the hot gas in WR 1 must reside interior to the radius of optical depth unity for the total absorptive opacity at the energy of the edge.},
  language  = {en}
}
@article{SidoliSgueraEspositoetal.2022,
  author    = {Sidoli, Lara and Sguera, Vito and Esposito, Paolo and Oskinova, Lida and Polletta, Maria del Carmen},
  title     = {XMM-Newton discovery of very high obscuration in the candidate Supergiant Fast X-ray Transient AX J1714.1-3912},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {512},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {2},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/stac691},
  pages     = {2929 -- 2935},
  year      = {2022},
  abstract  = {We have analysed an archival XMM-Newton EPIC observation that serendipitously covered the sky position of a variable X-ray source AX J1714.1-3912, previously suggested to be a Supergiant Fast X-ray Transient (SFXT). During the XMM-Newton observation the source is variable on a timescale of hundred seconds and shows two luminosity states, with a flaring activity followed by unflared emission, with a variability amplitude of a factor of about 50. We have discovered an intense iron emission line with a centroid energy of 6.4 keV in the power law-like spectrum, modified by a large absorption (N-H similar to 10(24) cm(-2)), never observed before from this source. This X-ray spectrum is unusual for an SFXT, but resembles the so-called 'highly obscured sources', high mass X-ray binaries (HMXBs) hosting an evolved B[e] supergiant companion (sgB[e]). This might suggest that AX J1714.1-3912 is a new member of this rare type of HMXBs, which includes IGR J16318-4848 and CI Camelopardalis. Increasing this small population of sources would be remarkable, as they represent an interesting short transition evolutionary stage in the evolution of massive binaries. Nevertheless, AX J1714.1-3912 appears to share X-ray properties of both kinds of HMXBs (SFXT versus sgB[e] HMXB). Therefore, further investigations of the companion star are needed to disentangle the two hypothesis.},
  language  = {en}
}
@inproceedings{OskinovaHamannFeldmeier2007,
  author    = {Oskinova, Lida and Hamann, Wolf-Rainer and Feldmeier, Achim},
  title     = {X-raying clumped stellar winds},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18133},
  year      = {2007},
  abstract  = {X-ray spectroscopy is a sensitive probe of stellar winds. X-rays originate from optically thin shock-heated plasma deep inside the wind and propagate outwards throughout absorbing cool material. Recent analyses of the line ratios from He-like ions in the X-ray spectra of O-stars highlighted problems with this general paradigm: the measured line ratios of highest ions are consistent with the location of the hottest X-ray emitting plasma very close to the base of the wind, perhaps indicating the presence of a corona, while measurements from lower ions conform with the wind-embedded shock model. Generally, to correctly model the emerging Xray spectra, a detailed knowledge of the cool wind opacities based on stellar atmosphere models is prerequisite. A nearly grey stellar wind opacity for the X-rays is deduced from the analyses of high-resolution X-ray spectra. This indicates that the stellar winds are strongly clumped. Furthermore, the nearly symmetric shape of X-ray emission line profiles can be explained if the wind clumps are radially compressed. In massive binaries the orbital variations of X-ray emission allow to probe the opacity of the stellar wind; results support the picture of strong wind clumping. In high-mass X-ray binaries, the stochastic X-ray variability and the extend of the stellar-wind part photoionized by X-rays provide further strong evidence that stellar winds consist of dense clumps.},
  language  = {en}
}
@phdthesis{Foster2022,
  author    = {Foster, Mary Grace},
  title     = {X-Ray studies of exoplanet systems},
  publisher = {xiii, 92},
  doi       = {10.25932/publishup-56215},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-562152},
  school      = {Universit{\"a}t Potsdam},
  pages     = {108},
  year      = {2022},
  abstract  = {X-rays are integral to furthering our knowledge of exoplanetary systems. In this work we discuss the use of X-ray observations to understand star-planet interac- tions, mass-loss rates of an exoplanet's atmosphere and the study of an exoplanet's atmospheric components using future X-ray spectroscopy. The low-mass star GJ 1151 was reported to display variable low-frequency radio emission, which is an indication of coronal star-planet interactions with an unseen exoplanet. In chapter 5 we report the first X-ray detection of GJ 1151's corona based on XMM-Newton data. Averaged over the observation, we detect the star with a low coronal temperature of 1.6 MK and an X-ray luminosity of LX = 5.5 × 1026 erg/s. This is compatible with the coronal assumptions for a sub-Alfv{\´e}nic star- planet interaction origin of the observed radio signals from this star. In chapter 6, we aim to characterise the high-energy environment of known ex- oplanets and estimate their mass-loss rates. This work is based on the soft X-ray instrument on board the Spectrum Roentgen Gamma (SRG) mission, eROSITA, along with archival data from ROSAT, XMM-Newton, and Chandra. We use these four X-ray source catalogues to derive X-ray luminosities of exoplanet host stars in the 0.2-2 keV energy band. A catalogue of the mass-loss rates of 287 exoplan- ets is presented, with 96 of these planets characterised for the first time using new eROSITA detections. Of these first time detections, 14 are of transiting exoplanets that undergo irradiation from their host stars that is of a level known to cause ob- servable evaporation signals in other systems, making them suitable for follow-up observations. In the next generation of space observatories, X-ray transmission spectroscopy of an exoplanet's atmosphere will be possible, allowing for a detailed look into the atmospheric composition of these planets. In chapter 7, we model sample spectra using a toy model of an exoplanetary atmosphere to predict what exoplanet transit observations with future X-ray missions such as Athena will look like. We then estimate the observable X-ray transmission spectrum for a typical Hot Jupiter-type exoplanet, giving us insights into the advances in X-ray observations of exoplanets in the decades to come.},
  language  = {en}
}
@article{ReicheBarberkaJanietzetal.1994,
  author    = {Reiche, J{\"u}rgen and Barberka, Thomas Andreas and Janietz, Dietmar and Hofmann, Dieter and Pietsch, Ullrich and Brehmer, Ludwig},
  title     = {X-ray structure investigation and computer modelling of Langmuir-Blodgett films formed from disc-shaped pentaalkines},
  year      = {1994},
  language  = {en}
}
@article{MiedemaMitznerGanschowetal.2017,
  author    = {Miedema, P. S. and Mitzner, Rolf and Ganschow, S. and F{\"o}hlisch, Alexander and Beye, Martin},
  title     = {X-ray spectroscopy on the active ion in laser crystals},
  series = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  volume    = {19},
  journal   = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9076},
  doi       = {10.1039/c7cp03026f},
  pages     = {21800 -- 21806},
  year      = {2017},
  abstract  = {The active ions in typical laser crystals were studied with Resonant Inelastic X-ray Scattering (RIXS) and Partial Fluorescence Yield X-ray Absorption (PFY-XAS) spectroscopies as solid state model systems for dilute active centers. We analyzed Ti3+ and Cr3+ in alpha-Al2O3:Ti3+ and LiCaAlF6:Cr3+, respectively. The comparison of experimental data with semi-empirical multiplet calculations provides insights into the electronic structure and shows how measured crystal field energies are related across different spectroscopies.},
  language  = {en}
}
@article{PietschBarberkaGeueetal.1997,
  author    = {Pietsch, Ullrich and Barberka, Thomas Andreas and Geue, Thomas and St{\"o}mmer, Ralph},
  title     = {X-ray scattering from thin organic films and multilayers},
  year      = {1997},
  language  = {en}
}
@phdthesis{Stoemmer1998,
  author    = {St{\"o}mmer, Ralph},
  title     = {X-ray scattering from silicon surfaces and thin oxides on silicon substrates},
  pages     = {108 S. : graph. Darst.},
  year      = {1998},
  language  = {en}
}
@article{StoemmerGoebelHubetal.1998,
  author    = {St{\"o}mmer, Ralph and G{\"o}bel, H. and Hub, W. and Pietsch, Ullrich},
  title     = {X-ray scattering from silicon surfaces},
  year      = {1998},
  language  = {en}
}
@phdthesis{Baumbach2000,
  author    = {Baumbach, Tilo},
  title     = {X-Ray scattering by periodic nanostructures},
  pages     = {182 S.},
  year      = {2000},
  language  = {en}
}
@article{PietschTsirelsonGorfan2003,
  author    = {Pietsch, Ullrich and Tsirelson, Vladimir G. and Gorfan, S. V.},
  title     = {X-ray scattering amplitude of an atom in a permanent external electric field},
  year      = {2003},
  language  = {en}
}
@article{PietschKubowiczThuenemannetal.2003,
  author    = {Pietsch, Ullrich and Kubowicz, Stephan and Th{\"u}nemann, Andreas F. and Geue, Thomas and Watson, M. D. and Tchebotareva, N. and M{\"u}llen, K.},
  title     = {X-ray reflectivity study of an amphiphilic hex-peri-hexabenzocoronene at a structured silicon wafer surface},
  year      = {2003},
  language  = {en}
}
@article{GeueHennebergPietsch2002,
  author    = {Geue, Thomas and Henneberg, Oliver and Pietsch, Ullrich},
  title     = {X-ray reflectivity from sinusoidal surface relief gratings},
  issn      = {0023-4753},
  year      = {2002},
  language  = {en}
}
@article{Pietsch2002,
  author    = {Pietsch, Ullrich},
  title     = {X-ray reflectivity from sinusoidal surface relief gratings},
  year      = {2002},
  language  = {en}
}
@article{PoloucekPietschGeueetal.2001,
  author    = {Poloucek, P. and Pietsch, Ullrich and Geue, Thomas and Symietz, Christian and Brezesinski, Gerald},
  title     = {X-ray reflectivity analysis of thin complex Langmuir-Blodgett films},
  year      = {2001},
  language  = {en}
}
@article{GiewekemeyerKruegerKalbfleischetal.2011,
  author    = {Giewekemeyer, K. and Krueger, S. P. and Kalbfleisch, S. and Bartels, Meike and Beta, Carsten and Salditt, T.},
  title     = {X-ray propagation microscopy of biological cells using waveguides as a quasipoint source},
  series = {Physical review : A, Atomic, molecular, and optical physics},
  volume    = {83},
  journal   = {Physical review : A, Atomic, molecular, and optical physics},
  number    = {2},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {1050-2947},
  doi       = {10.1103/PhysRevA.83.023804},
  pages     = {7},
  year      = {2011},
  abstract  = {We have used x-ray waveguides as highly confining optical elements for nanoscale imaging of unstained biological cells using the simple geometry of in-line holography. The well-known twin-image problem is effectively circumvented by a simple and fast iterative reconstruction. The algorithm which combines elements of the classical Gerchberg-Saxton scheme and the hybrid-input-output algorithm is optimized for phase-contrast samples, well-justified for imaging of cells at multi-keV photon energies. The experimental scheme allows for a quantitative phase reconstruction from a single holographic image without detailed knowledge of the complex illumination function incident on the sample, as demonstrated for freeze-dried cells of the eukaryotic amoeba Dictyostelium discoideum. The accessible resolution range is explored by simulations, indicating that resolutions on the order of 20 nm are within reach applying illumination times on the order of minutes at present synchrotron sources.},
  language  = {en}
}
@article{ToalaOskinovaGonzalezGalanetal.2016,
  author    = {Toala, Jes{\´u}s Alberto and Oskinova, Lida and Gonzalez-Galan, Ana and Guerrero, Mart{\´i}n A. and Ignace, R. and Pohl, Martin},
  title     = {X-RAY OBSERVATIONS OF BOW SHOCKS AROUND RUNAWAY O STARS. THE CASE OF zeta OPH AND BD+43 degrees 3654},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {821},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/0004-637X/821/2/79},
  pages     = {9},
  year      = {2016},
  abstract  = {Non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. We present X-ray observations toward the runaway stars zeta Oph by Chandra and Suzaku and of BD+43 degrees 3654 by XMM-Newton to search for the presence of non-thermal X-ray emission. We found no evidence of non-thermal emission spatially coincident with the bow shocks; nonetheless, diffuse emission was detected in the vicinity of zeta Oph. After a careful analysis of its spectral characteristics, we conclude that this emission has a thermal nature with a plasma temperature of T approximate to 2 x 10(6) K. The cometary shape of this emission seems to be in line with recent predictions of radiation-hydrodynamic models of runaway stars. The case of BD+43 degrees 3654 is puzzling, as non-thermal emission has been reported in a previous work for this source.},
  language  = {en}
}
@article{OskinovaFeldmeierHamann2003,
  author    = {Oskinova, Lida and Feldmeier, Achim and Hamann, Wolf-Rainer},
  title     = {X-ray line profiles from structured stellar winds},
  isbn      = {1-58381-133-8},
  year      = {2003},
  abstract  = {Absorbing material compressed in a number of thin shells is effectively less opaque for X-rays than smoothly distributed gas. The calculated X-ray emission line profiles are red-shifted if the emission arises from the starward side of the shells.},
  language  = {en}
}
@article{FeldmeierOskinovaHamann2003,
  author    = {Feldmeier, Achim and Oskinova, Lida and Hamann, Wolf-Rainer},
  title     = {X-ray line emission from a fragmented stellar wind},
  year      = {2003},
  abstract  = {We discuss X-ray line formation in dense O star winds. A random distribution of wind shocks is assumed to emit X-rays that are partially absorbed by cooler wind gas. The cool gas resides in highly compressed fragments oriented perpendicular to the radial flow direction. For fully opaque fragments, we find that the blueshifted part of X-ray line profiles remains flat-topped even after severe wind attenuation, whereas the red part shows a steep decline. These box- type, blueshifted profiles resemble recent Chandra observations of the O3 star zeta Pup. For partially transparent fragments, the emission lines become similar to those from a homogeneous wind.},
  language  = {en}
}
@article{PoppenhaegerKetzerMallonn2020,
  author    = {Poppenh{\"a}ger, Katja and Ketzer, Laura and Mallonn, Matthias},
  title     = {X-ray irradiation and evaporation of the four young planets around V1298 Tau},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {500},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {4},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/staa1462},
  pages     = {4560 -- 4572},
  year      = {2020},
  abstract  = {Planets around young stars are thought to undergo atmospheric evaporation due to the high magnetic activity of the host stars. Here we report on X-ray observations of V1298 Tau, a young star with four transiting exoplanets. We use X-ray observations of the host star with Chandra and ROSAT to measure the current high-energy irradiation level of the planets and employ a model for the stellar activity evolution together with exoplanetary mass-loss to estimate the possible evolution of the planets. We find that V1298 Tau is X-ray bright with log L-X [erg s(-1)] = 30.1 and has a mean coronal temperature of approximate to 9 MK. This places the star amongst the more X-ray luminous ones at this stellar age. We estimate the radiation-driven mass-loss of the exoplanets and find that it depends sensitively on the possible evolutionary spin-down tracks of the star as well as on the current planetary densities. Assuming the planets are of low density due to their youth, we find that the innermost two planets can lose significant parts of their gaseous envelopes and could be evaporated down to their rocky cores depending on the stellar spin evolution. However, if the planets are heavier and follow the mass-radius relation of older planets, then even in the highest XUV irradiation scenario none of the planets is expected to cross the radius gap into the rocky regime until the system reaches an age of 5 Gyr.},
  language  = {en}
}
@article{GeueSchultzGrenzeretal.2000,
  author    = {Geue, Thomas and Schultz, Michael and Grenzer, J{\"o}rg and Natansohn, Almeria and Rochon, Paul},
  title     = {X-ray investigations of the molecular mobility with polymer surface gratings},
  year      = {2000},
  language  = {en}
}
@article{PietschGeueHennebergetal.2003,
  author    = {Pietsch, Ullrich and Geue, Thomas and Henneberg, Oliver and Saphiannikova, Marina},
  title     = {X-ray investigations of formation efficiency of buried azobenzene polymer density gratings},
  doi       = {10.1063/1.1554753},
  year      = {2003},
  language  = {en}
}