TY - CHAP
A1 - Popp, Alexander
A1 - Blaum, Niels
A1 - Domptail, Stephanie
A1 - Herpel, Nicole
A1 - Gröngröft, Alexander
A1 - Hoffman, T. T.
A1 - Jürgens, Norbert
A1 - Milton, Sue
A1 - Nuppenau, Ernst-August
A1 - Rossmanith, Eva
A1 - Schmidt, Michael
A1 - Vogel, Melanie
A1 - Vohland, Katrin
A1 - Jeltsch, Florian
T1 - From satellite imagery to soil-plant interactions
BT - integrating disciplines and scales in process based simulation models
N2 - Decisions for the conservation of biodiversity and sustainable management of natural resources are typically related to large scales, i.e. the landscape level. However, understanding and predicting the effects of land use and climate change on scales relevant for decision-making requires to include both, large scale vegetation dynamics and small scale processes, such as soil-plant interactions. Integrating the results of multiple BIOTA subprojects enabled us to include necessary data of soil science, botany, socio-economics and remote sensing into a high resolution, process-based and spatially-explicit model. Using an example from a sustainably-used research farm and a communally used and degraded farming area in semiarid southern Namibia we show the power of simulation models as a tool to integrate processes across disciplines and scales.
Y1 - 2006
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7302
N1 - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006.
[Poster]
ER -
TY - CHAP
A1 - Rossmanith, Eva
A1 - Blaum, Niels
A1 - Keil, Manfred
A1 - Langerwisch, F.
A1 - Meyer, Jork
A1 - Popp, Alexander
A1 - Schmidt, Michael
A1 - Schultz, Christoph
A1 - Schwager, Monika
A1 - Vogel, Melanie
A1 - Wasiolka, Bernd
A1 - Jeltsch, Florian
T1 - Scaling up local population dynamics to regional scales
BT - an integrated approach
N2 - In semi-arid savannas, unsustainable land use can lead to degradation of entire landscapes, e.g. in the form of shrub encroachment. This leads to habitat loss and is assumed to reduce species diversity. In BIOTA phase 1, we investigated the effects of land use on population dynamics on farm scale. In phase 2 we scale up to consider the whole regional landscape consisting of a diverse mosaic of farms with different historic and present land use intensities. This mosaic creates a heterogeneous, dynamic pattern of structural diversity at a large spatial scale. Understanding how the region-wide dynamic land use pattern affects the abundance of animal and plant species requires the integration of processes on large as well as on small spatial scales. In our multidisciplinary approach, we integrate information from remote sensing, genetic and ecological field studies as well as small scale process models in a dynamic region-wide simulation tool.
Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006.
Y1 - 2006
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7320
N1 - [Poster]
ER -
TY - JOUR
A1 - Baier, Dieter
A1 - Soyez, Konrad
A1 - Streurs, Kerstin
A1 - Kaiser, Jürgen
A1 - Narodoslawski, Michael
A1 - Kamm, Birgit
A1 - Kromus, Stefan
A1 - Kamm, Michael
A1 - Zierke, Irene
A1 - Koller, Matthias
A1 - Hermann, Tim
A1 - Schmeer, Ernst
A1 - Thrän, Daniela
A1 - Kleinpeter, Erich
A1 - Starke, Ines
A1 - Holzberger, Anja
T1 - Umweltforschung für das Land Brandenburg
BT - Projekt Ökotechnologie / Regenerative Energien
JF - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam
N2 - BAIER, D.; SOYEZ, K.: Dekontamination von Altholz ; BAIER, D. et al.: Untersuchungen zur Kompostierbarkeit von paraffinbeschichteten Verpackungsmaterialien ; KAISER, J.; SOYEZ, K.: Zum Wasser- und Wärmehaushalt des Intensivrotteprozesses der mechanisch-biologischen Abfallbehandlung ; KAMM, B. et al.: Green Biorefinery - European Network for the Implementation of Biorefineries (NIB) ; KAMM, B. et al.: Grüne Bioraffinerie Brandenburg ; KOLLER, M.; HERMANN, T.: Entscheidungshilfen für die ökologische Optimierung der Entsorgung häuslicher Restabfälle ; SCHMEER, E.: Solarthermie 2000 ; SCHMEER, E.: Forschungs- und Demonstrationsanlage zur Photovoltaik ; SOYEZ, K. et al.: Verbundvorhaben "Mechanisch-biologische Restabfallbehandlung" ; STARKE, I. et al.: Carbohydrates as raw material from a Green BioRefinery
Y1 - 2000
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3831
SN - 1434-2375
SN - 1611-9339
VL - 8
SP - 230
EP - 301
ER -
TY - GEN
A1 - Ye, Fangyuan
A1 - Zhang, Shuo
A1 - Warby, Jonathan
A1 - Wu, Jiawei
A1 - Gutierrez-Partida, Emilio
A1 - Lang, Felix
A1 - Shah, Sahil
A1 - Saglamkaya, Elifnaz
A1 - Sun, Bowen
A1 - Zu, Fengshuo
A1 - Shoaee, Safa
A1 - Wang, Haifeng
A1 - Stiller, Burkhard
A1 - Neher, Dieter
A1 - Zhu, Wei-Hong
A1 - Stolterfoht, Martin
A1 - Wu, Yongzhen
T1 - Overcoming C₆₀-induced interfacial recombination in inverted perovskite solar cells by electron-transporting carborane
T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - Inverted perovskite solar cells still suffer from significant non-radiative recombination losses at the perovskite surface and across the perovskite/C₆₀ interface, limiting the future development of perovskite-based single- and multi-junction photovoltaics. Therefore, more effective inter- or transport layers are urgently required. To tackle these recombination losses, we introduce ortho-carborane as an interlayer material that has a spherical molecular structure and a three-dimensional aromaticity. Based on a variety of experimental techniques, we show that ortho-carborane decorated with phenylamino groups effectively passivates the perovskite surface and essentially eliminates the non-radiative recombination loss across the perovskite/C₆₀ interface with high thermal stability. We further demonstrate the potential of carborane as an electron transport material, facilitating electron extraction while blocking holes from the interface. The resulting inverted perovskite solar cells deliver a power conversion efficiency of over 23% with a low non-radiative voltage loss of 110 mV, and retain >97% of the initial efficiency after 400 h of maximum power point tracking. Overall, the designed carborane based interlayer simultaneously enables passivation, electron-transport and hole-blocking and paves the way toward more efficient and stable perovskite solar cells.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1317
Y1 - 2022
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-587705
SN - 1866-8372
IS - 1317
ER -
TY - GEN
A1 - Löhmannsröben, Hans-Gerd
A1 - Kantor, Zoltan
A1 - Kumke, Michael Uwe
A1 - Schmälzlin, Elmar
A1 - Reich, Oliver
T1 - OPQS – optische Prozess- und Qualitäts-Sensorik
N2 - Im vorliegenden Beitrag wird an Hand dreier Beispiele der Einsatz von optischer Sensorik zur Produktcharakterisierung dargestellt, nämlich Untersuchungen zum O2-Gehalt in Fruchtsäften, zur Isotopiesignatur von CO2 in Mineralwässern und zu Lichtstreueigenschaften eines Sonnenschutzmittels. Inhalt: Bestimmung von O2 mit Lumineszenzsonden Isotopenselektive Bestimmung von CO2 mit TDLAS Optische Charakterisierung stark streuender Materialien mit Photonendichtewellen
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 028
KW - Sensorik
KW - Prozesskontrolle
KW - Absorption
KW - Lumineszenz
KW - Lichtstreuung
KW - Isotopie
Y1 - 2005
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13205
ER -
TY - THES
A1 - Zeuschner, Steffen Peer
T1 - Magnetoacoustics observed with ultrafast x-ray diffraction
N2 - In the present thesis I investigate the lattice dynamics of thin film hetero structures of magnetically ordered materials upon femtosecond laser excitation as a probing and manipulation scheme for the spin system. The quantitative assessment of laser induced thermal dynamics as well as generated picosecond acoustic pulses and their respective impact on the magnetization dynamics of thin films is a challenging endeavor. All the more, the development and implementation of effective experimental tools and comprehensive models are paramount to propel future academic and technological progress.
In all experiments in the scope of this cumulative dissertation, I examine the crystal lattice of nanoscale thin films upon the excitation with femtosecond laser pulses. The relative change of the lattice constant due to thermal expansion or picosecond strain pulses is directly monitored by an ultrafast X-ray diffraction (UXRD) setup with a femtosecond laser-driven plasma X-ray source (PXS). Phonons and spins alike exert stress on the lattice, which responds according to the elastic properties of the material, rendering the lattice a versatile sensor for all sorts of ultrafast interactions. On the one hand, I investigate materials with strong magneto-elastic properties; The highly magnetostrictive rare-earth compound TbFe2, elemental Dysprosium or the technological relevant Invar material FePt. On the other hand I conduct a comprehensive study on the lattice dynamics of Bi1Y2Fe5O12 (Bi:YIG), which exhibits high-frequency coherent spin dynamics upon femtosecond laser excitation according to the literature. Higher order standing spinwaves (SSWs) are triggered by coherent and incoherent motion of atoms, in other words phonons, which I quantified with UXRD. We are able to unite the experimental observations of the lattice and magnetization dynamics qualitatively and quantitatively. This is done with a combination of multi-temperature, elastic, magneto-elastic, anisotropy and micro-magnetic modeling.
The collective data from UXRD, to probe the lattice, and time-resolved magneto-optical Kerr effect (tr-MOKE) measurements, to monitor the magnetization, were previously collected at different experimental setups. To improve the precision of the quantitative assessment of lattice and magnetization dynamics alike, our group implemented a combination of UXRD and tr-MOKE in a singular experimental setup, which is to my knowledge, the first of its kind. I helped with the conception and commissioning of this novel experimental station, which allows the simultaneous observation of lattice and magnetization dynamics on an ultrafast timescale under identical excitation conditions. Furthermore, I developed a new X-ray diffraction measurement routine which significantly reduces the measurement time of UXRD experiments by up to an order of magnitude. It is called reciprocal space slicing (RSS) and utilizes an area detector to monitor the angular motion of X-ray diffraction peaks, which is associated with lattice constant changes, without a time-consuming scan of the diffraction angles with the goniometer. RSS is particularly useful for ultrafast diffraction experiments, since measurement time at large scale facilities like synchrotrons and free electron lasers is a scarce and expensive resource. However, RSS is not limited to ultrafast experiments and can even be extended to other diffraction techniques with neutrons or electrons.
N2 - In der vorliegenden Arbeit untersuche ich die Gitterdynamik von magnetisch geordneten und dünnen Filmen, deren Spinsystem mit Femtosekunden-Laserpulsen angeregt und untersucht wird. Die Quantifizierung der laserinduzierten thermischen Dynamik, der erzeugten Pikosekunden-Schallpulse sowie deren jeweiliger Einfluss auf die Magnetisierungsdynamik ist ein schwieriges Unterfangen. Umso mehr ist die Entwicklung und Anwendung von effizienten experimentellen Konzepten und umfangreichen Modellen grundlegend für das Antreiben des zukünftigen wissenschaftlichen und technologischen Fortschritt.
In jedem Experiment dieser kummulativen Dissertation untersuche ich das Kristallgitter von Nanometer dünnen Filmen nach der Anregung mit Femtosekunden-Laserpulsen. Die relative Änderung der Gitterkonstante, hervorgerufen durch thermische Ausdehnung oder Pikosekunden-Schallpulse, wird dabei direkt mittels ultraschneller Röntgenbeugung (UXRD) gemessen. Der Aufbau nutzt zur Bereitstellung von ultrakurzen Röntgenpulsen eine lasergetriebene Plasma-Röntgenquelle (PXS). Phononen und Spins üben gleichermaßen einen Druck auf das Gitter aus, welches entsprechend der elastsischen Eigenschaften des Materials reagiert, was das Gitter zu einem vielseitigen Sensor für ultraschenlle Wechselwirkungen macht. Zum einen untersuche ich Materialien mit starken magnetoelastischen Eigentschaften: die stark magnetostriktive Seltenen-Erden-Verbindung TbFe2, elementares Dysprosium oder das technologisch relavante Invar-Material FePt. Zum anderen habe ich eine umfangreiche Studie der Gitterdynamik von Bi1Y2Fe5O12 (Bi:YIG) angestellt, in dem der Literatur zufolge hochfrequente kohärente Spindynamiken durch Femtosekunden-Laseranregung zu beobachten sind. Diese stehenden Spinwellen (SSWs) höherer Ordnung entstehen durch die kohärente und inkohärente Bewegung von Atomen, in anderen Worten Phononen, welche ich durch UXRD vermessen habe. Somit sind wir in der Lage, die experimentellen Beobachtungen der Gitter- und Spindynamik qualitativ und quantitativ zu vereinigen. Dies geschieht durch eine Kombination von Viel-Temperatur- und Anisotropiemodellierung sowie elastische, magnetoelastische, und mikromagnetsiche Modelle.
Die gemeinsamen Daten von UXRD und der zeitaufgelösten magnetooptischen Kerr-Effekt Messungen (tr-MOKE), um jeweils die Gitter- und Spindynamik zu messen, wurden in der Vergangenheit noch an unterschiedlichen experimentellen Aufbauten gemessen. Um die Quantifizierung präziser zu gestalten, haben wir in unserer Arbeitsgruppe UXRD und tr-MOKE in einem einzigen Aufbau kombiniert, welcher somit meines Wissens der erste seiner Art ist. Ich half bei dem Entwurf und der Inbetriebnahme des neuen Aufbaus, welcher die gleichzeitige Messung von Gitter- und Spindynamik auf einer ultraschnellen Zeitskala unter identischen Anregungsbedingungen ermöglicht. Außerdem entwickelte ich eine neue Messroutine für Röntgenbeugung, welche die Messzeit von UXRD-Experimenten um bis zu einer Größenordnungen reduziert. Es nennt sich das Schneiden des reziproken Raumes (reciprocal space slicing, RSS) und nutzt den Vorteil von Flächendetektoren die Bewegung von Beugungsreflexen zu detektieren, was von einer Änderung der Gitterkonstante einhergeht, ohne zeitintensive Scans der Beugungswinkel mit dem Goniometer durchzuführen. RSS ist besonders nützlich für ultraschnelle Beugungsexperimente, weil die Messzeit an Großgeräten wie Synchrotrons oder Freie Elektronen Laser eine seltene und teure Ressource ist. Darüber hinaus ist RSS nicht zwangsläufig auf die Anwendung in ultraschnellen Experimenten beschränkt und kann sogar auf andere Beugungsexperimente, wie die mit Neutronen und Elektronen, ausgeweitet werden.
KW - ultrafast
KW - X-ray diffraction
KW - thin films
KW - magnetoelasticity
KW - ultraschnell
KW - Röntgenbeugung
KW - dünne Filme
KW - Magnetoelastizität
Y1 - 2022
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-561098
ER -
TY - GEN
A1 - Dimigen, Olaf
A1 - Valsecchi, Matteo
A1 - Sommer, Werner
A1 - Kliegl, Reinhold
T1 - Human Microsaccade-Related Visual Brain Responses
N2 - Microsaccades are very small, involuntary flicks in eye position that occur on average once or twice per second during attempted visual fixation. Microsaccades give rise to EMG eye muscle spikes that can distort the spectrum of the scalp EEG and mimic increases in gamma band power. Here we demonstrate that microsaccades are also accompanied by genuine and sizeable cortical activity, manifested in the EEG. In three experiments, high-resolution eye movements were corecorded with the EEG: during sustained fixation of checkerboard and face stimuli and in a standard visual oddball task that required the counting of target stimuli. Results show that microsaccades as small as 0.15° generate a field potential over occipital cortex and midcentral scalp sites 100 –140 ms after movement onset, which resembles the visual lambda response evoked by larger voluntary saccades. This challenges the standard assumption of human brain imaging studies that saccade-related brain activity is precluded by fixation, even when fully complied with. Instead, additional cortical potentials from microsaccades were present in 86% of the oddball task trials and of similar amplitude as the visual response to stimulus onset. Furthermore, microsaccade probability varied systematically according to the proportion of target stimuli in the oddball task, causing modulations of late stimulus-locked event-related potential (ERP) components. Microsaccades present an unrecognized source of visual brain signal that is of interest for vision research and may have influenced the data of many ERP and neuroimaging studies.
T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 240
Y1 - 2009
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-56923
ER -
TY - GEN
A1 - Kliegl, Reinhold
A1 - Masson, Michael E. J.
A1 - Richter, Eike M.
T1 - A linear mixed model analysis of masked repetition priming
N2 - We examined individual differences in masked repetition priming by re-analyzing item-level response-time (RT) data from three experiments. Using a linear mixed model (LMM) with subjects and items specified as crossed random factors, the originally reported priming and word-frequency effects were recovered. In the same LMM, we estimated parameters describing the distributions of these effects across subjects. Subjects’ frequency and priming effects correlated positively with each other and negatively with mean RT. These correlation estimates, however, emerged only with a reciprocal transformation of RT (i.e., -1/RT), justified on the basis of distributional analyses. Different correlations, some with opposite sign, were obtained (1) for untransformed or logarithmic RTs or (2) when correlations were computed using within-subject analyses. We discuss the relevance of the new results for accounts of masked priming, implications of applying RT transformations, and the use of LMMs as a tool for the joint analysis of experimental effects and associated individual differences.
T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 247
Y1 - 2009
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57073
ER -
TY - GEN
A1 - Kliegl, Reinhold
A1 - Bates, Douglas
T1 - International Collaboration in Psychology is on the Rise
N2 - There has been a substantial increase in the percentage for publications with co-authors located in departments from different countries in 12 major journals of psychology. The results are evidence for a remarkable internationalization of psychological research, starting in the mid 1970s and increasing in rate at the beginning of the 1990s. This growth occurs against a constant number of articles with authors from the same country; it is not due to a concomitant increase in the number of co-authors per article. Thus, international collaboration in psychology is obviously on the rise.
T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 244
Y1 - 2011
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57045
ER -
TY - GEN
A1 - Fiedler, Klaus
A1 - Kliegl, Reinhold
A1 - Lindenberger, Ulman
A1 - Mausfeld, Rainer
A1 - Mummendey, Amélie
A1 - Prinz, Wolfgang
T1 - Psychologie im 21. Jahrhundert: Führende deutsche Psychologen über Lage und Zukunft ihres Fachs und die Rolle der psychologischen Grundlagenforschung
T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 245
Y1 - 2005
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57051
ER -