TY - GEN
AU - Kirchgässner, Wilhelm
AU - Wallscheid, Oliver
AU - Böcker, Joachim
ID - 29655
T2 - arXiv preprint arXiv:2103.16323
TI - Thermal Neural Networks: Lumped-Parameter Thermal Modeling With State-Space Machine Learning
ER -
TY - JOUR
AB - In order to reduce the fuel consumption and consequently the greenhouse emissions, the automotive industry is implementing lightweight constructions in the body in white production. As a result, the use of aluminum alloys is continuously increasing. Due to poor weldability of aluminum in combination with other materials, mechanical joining technologies like clinching are increasingly used. In order to predict relevant characteristics of clinched joints and to ensure the reliability of the process, it is simulated numerically during product development processes. In this regard the predictive accuracy of the simulated process highly depends on the implemented friction model. In particular, the frictional behavior between the sheet metals affects the geometrical formation of the clinched joint significantly. This paper presents a testing method, which enables to determine the frictional coefficients between sheet metal materials for the simulation of clinching processes. For this purpose, the correlation of interface pressure and the relative velocity between aluminum sheets in clinching processes is investigated using numerical simulation. Furthermore, the developed testing method focuses on the specimen geometry as well as the reproduction of the occurring friction conditions between two sheet metal materials in clinching processes. Based on a methodical approach the test setup is explained and the functionality of the method is proven by experimental tests using sheet metal material EN AW6014.
AU - Rossel, Moritz Sebastian
AU - Böhnke, Max
AU - Bielak, Christian Roman
AU - Bobbert, Mathias
AU - Meschut, Gerson
ID - 34227
JF - Key Engineering Materials
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
SN - 1662-9795
TI - Development of a Method for the Identification of Friction Coefficients in Sheet Metal Materials for the Numerical Simulation of Clinching Processes
VL - 883
ER -
TY - JOUR
AU - Sherman, David A.
AU - Lehmann, Tim
AU - Baumeister, Jochen
AU - Grooms, Dustin R.
AU - Norte, Grant E.
ID - 32437
IS - 2
JF - Experimental Brain Research
KW - General Neuroscience
SN - 0014-4819
TI - Somatosensory perturbations influence cortical activity associated with single-limb balance performance
VL - 240
ER -
TY - GEN
AU - Ludwig, Janis
AU - Kykal, Carsten
AU - Schmid, Hans-Joachim
ID - 27551
KW - aerosol spreading
KW - SARS-CoV-2
KW - indoor air filtration
T2 - Book of abstracts for the 2021 European Aerosol Conference
TI - Assessing spreading and removal of virus laden aerosols in different settings using an aerosol method (Presentation)
ER -
TY - GEN
AU - Ludwig, Janis
AU - Schmid, Hans-Joachim
ID - 27553
TI - Synthese und asymmetrische Funktionalisierung von submikronen Janus-Polymer-Partikeln in der Gasphase (Poster)
ER -
TY - CHAP
AU - Matzner, Tobias
ED - Sprenger, Florian
ID - 42904
T2 - Autonome Autos – Die Zukunft des Verkehrs und die Dispositive der Mobilität
TI - Die Fussgänger*innen autonomer Kraftfahrzeuge. Eine informatische Dispositivanalyse
ER -
TY - CONF
AU - Lange, Sven
AU - Hedayat, Christian
AU - Kuhn, Harald
AU - Hilleringmann, Ulrich
ID - 39401
T2 - 2021 Smart Systems Integration (SSI)
TI - Adaptation and Optimization of Planar Coils for a More Accurate and Far-Reaching Magnetic Field-Based Localization in the Near Field
ER -
TY - CONF
AU - Petrov, Dmitry
AU - Kroschewski, Konstantin
AU - Mwammenywa, Ibrahim
AU - Kagarura, G. Mark
AU - Hilleringmann, Ulrich
ID - 39927
T2 - 2021 IEEE Sensors
TI - Low-Cost NB-IoT Microgrid Power Quality Monitoring System
ER -
TY - CONF
AU - Petrov, Dmitry
AU - Kroschewski, Konstantin
AU - Hilleringmann, Ulrich
ID - 39397
T2 - 2021 Smart Systems Integration (SSI)
TI - Microcontroller Firmware Design for Industrial Wireless Sensors
ER -
TY - CONF
AU - Reker, Julia
AU - Meyers, Thorsten
AU - Vidor, Fabio F.
AU - Joubert, Trudi-Heleen
AU - Hilleringmann, Ulrich
ID - 39384
T2 - 2021 IEEE AFRICON
TI - Influence of electrode metallization on thin-film transistor performance
ER -
TY - CONF
AU - Sander, Tom
AU - Lange, Sven
AU - Hilleringmann, Ulrich
AU - Geneis, Volker
AU - Hedayat, Christian
AU - Kuhn, Harald
AU - Gockel, Franz-Barthold
ID - 39392
T2 - 2021 22nd IEEE International Conference on Industrial Technology (ICIT)
TI - Detection of Defects on Irregular Structured Surfaces by Image Processing Methods for Feature Extraction
ER -
TY - CONF
AU - Lange, Sven
AU - Schroder, Dominik
AU - Hedayat, Christian
AU - Kuhn, Harald
AU - Hilleringmann, Ulrich
ID - 39390
T2 - 2021 22nd IEEE International Conference on Industrial Technology (ICIT)
TI - Development of Methods for Coil-Based Localization by Magnetic Fields of Miniaturized Sensor Platforms in Bioprocesses
ER -
TY - CHAP
AU - Hilleringmann, Ulrich
ID - 39394
SN - 9780128189009
T2 - Nanostructured Zinc Oxide
TI - ZnO nanoparticle films as active layer for thin film transistors
ER -
TY - CONF
AU - Reker, Julia
AU - Meyers, Thorsten
AU - Vidor, Fabio F.
AU - Joubert, Trudi-Heleen
AU - Hilleringmann, Ulrich
ID - 39396
T2 - 2021 Smart Systems Integration (SSI)
TI - Complementary Inverter Circuits on Flexible Substrates
ER -
TY - CONF
AU - Reker, Julia
AU - Meyers, Thorsten
AU - Vidor, Fabio F.
AU - Joubert, Trudi-Heleen
AU - Hilleringmann, Ulrich
ID - 39388
T2 - 2021 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS)
TI - Integration Process for Self-aligned Sub-µm Thin-Film Transistors for Flexible Electronics
ER -
TY - GEN
ID - 41288
TI - Entwicklung einer konstruktionsbasierten französischen Grammatik: ein Arbeitsbericht zum Adjektiv- und Nominalbandd
ER -
TY - BOOK
AU - Siepmann, Dirk
AU - Bürgel, Christoph
ID - 41221
TI - Grammatik des gesprochenen und geschriebenen Französisch: Das Nomen,
VL - 2
ER -
TY - GEN
ID - 41269
TI - Lexiko-grammatische Konstruktionen als Kern der Spracharbeit im Spanischunterricht, in: Hispanorama
ER -
TY - GEN
ID - 41267
TI - Hörverstehenskompetenz: Spanischstudierende auf dem Prüfstand der Abituraufgaben
ER -
TY - JOUR
AU - Burgfeld-Meise, Bianca
AU - Dehmel, Lukas
ID - 43148
JF - Zeitschrift MedienPädagogik 42
TI - Subjektwissen als Bildungsperspektive junger Erwachsener. Self-Tracking-Apps als digitale Optimierungstechnologien im Spannungsgefüge von Kontrolle und Selbstermächtigung
ER -
TY - JOUR
AU - Damm, Jannis
AU - Albiez, Matthias
AU - Göddecke, Johannes
AU - Meschut, Gerson
AU - Ummenhofer, Thomas
ID - 43159
IS - 9
JF - adhäsion KLEBEN & DICHTEN
KW - Polymers and Plastics
KW - General Chemical Engineering
KW - General Chemistry
SN - 1619-1919
TI - Dämpfungseigenschaften geklebter Verbindungen - Potenzialanalyse und Klebstoffcharakterisierung
VL - 65
ER -
TY - JOUR
AB - Der Beitrag referiert Ergebnisse studentischer Forschungsprojekte, die sich mit den Folgen der Corona-Pandemie für die berufliche Bildung, für Berufswahl, Berufsvorbereitung und Ausbildung befasst haben. Die Ergebnisse zeigen nicht nur, wie unterschiedlich Berufe und Branchen von der Krise betroffen waren und damit umgegangen sind, sondern geben auch Hinweise auf nötige Weiterentwicklungen zur Verbesserung der Resilienz von Branchen, Berufen, Betrieben und ihrer Ausbildung.
AU - Heisler, Dietmar
ID - 43179
JF - Berufsbildung. Zeitschrift für Theorie-Praxis-Dialog
KW - Pandemie
KW - Distanzlernen
KW - Berufswahl
KW - Ausbildung
SN - 00059536
TI - Berufsausbildung in der Corona-Pandemie. Befunde studentischer Forschungsprojekte
VL - 192
ER -
TY - CHAP
AU - Heisler, Dietmar
AU - Reißland, Jens
AU - Müller, Claudia
AU - Rühr, Laura
AU - Gröger, Simon
ED - Melzig, Christian
ED - Kuhlmeier, Werner
ED - Kretschmer, Susanne
ID - 43182
SN - 978-3-8474-2951-7
T2 - Berufsbildung für nachhaltige Entwicklung. Die Modellversuche 2015-2019 auf dem Weg vom Projekt zur Struktur
TI - Das Analyseraster zu Merkmalen eines nachhaltigen Lernortes für betriebliche Ausbilderinnen und Ausbilder.
ER -
TY - JOUR
AB - Im Fokus steht das Problem der Durchlässigkeit von akademischer und beruflicher Bildung im Kontext aktueller Reformen. Die Erhöhung sozialer Mobilität als Reformziel gerät darin zugunsten der Attraktivitätssteigerung von Bildungsgängen aus dem Blick. Die geringe Durchlässigkeit von Bildungsgängen wird primär als Marketingproblem thematisiert.
AU - Heisler, Dietmar
ID - 43178
JF - Berufsbildung. Zeitschrift für Theorie-Praxis-Dialog
KW - allgemeine Bildung
KW - berufliche BIldung
KW - Durchlässigkeit im Bildungssystem
SN - 00059536
TI - Berufsausbildung zwischen Attraktivitätsverlust und sozialer Ungleichheit Reformen für mehr Durchlässigkeit zwischen beruflicher und akademischer Bildung
VL - 191
ER -
TY - JOUR
AB - We show the existence of ground states in the massless spin boson model without any infrared regularization. Our proof is non-perturbative and relies on a compactness argument. It works for arbitrary values of the coupling constant under the hypothesis that the second derivative of the ground state energy as a function of a constant external magnetic field is bounded.
AU - Hasler, David
AU - Hinrichs, Benjamin
AU - Siebert, Oliver
ID - 43465
IS - 1
JF - Communications in Mathematical Physics
SN - 0010-3616
TI - On Existence of Ground States in the Spin Boson Model
VL - 388
ER -
TY - GEN
AU - Schroeter-Wittke, Harald
ID - 41089
SN - 0540–6226
T2 - Jahrbuch für Evangelische Kirchengeschichte des Rheinlandes
TI - Andrea Strübind / Klaas-Dieter Voß (Hgg.), Märtyrerbücher und ihre Bedeutung für konfessionelle Identität und Spiritualität in der Frühen Neuzeit. Interkonfessionelle und interdisziplinäre Beiträge zur Erforschung einer Buchgattung (SMHR 109), Tübingen 2019
VL - 70
ER -
TY - GEN
AU - Schroeter-Wittke, Harald
ID - 41087
SN - 0540–6226
T2 - Jahrbuch für Evangelische Kirchengeschichte des Rheinlandes
TI - Stefan Alkier (Hg.), Sola Scriptura 1517-2017. Rekonstruktionen – Kritiken – Transformationen – Performanzen (CHTh 7), Tübingen 2019
VL - 70
ER -
TY - CONF
AU - Ahmed, Qazi Arbab
ID - 29138
T2 - 2021 IFIP/IEEE 29th International Conference on Very Large Scale Integration (VLSI-SoC)
TI - Hardware Trojans in Reconfigurable Computing
ER -
TY - JOUR
AU - Schulze, Johanna
ID - 43389
JF - GGG-Magazin: DIE SCHULE für alle
TI - Einzelschulentwicklung gerecht und digital – Einblicke in die empirische Lage und Konsequenzen für die Praxis.
VL - 4
ER -
TY - BOOK
AU - Schulze, Johanna
ID - 43388
TI - Medienkonzepte zur chancengerechten Schulentwicklung. Fallstudien an Schulen mit besonders herausfordernden Schüler*innenkompositionen.
ER -
TY - JOUR
AU - Luo, Kai Hong
AU - Santandrea, Matteo
AU - Stefszky, Michael
AU - Sperling, Jan
AU - Massaro, Marcello
AU - Ferreri, Alessandro
AU - Sharapova, Polina
AU - Herrmann, Harald
AU - Silberhorn, Christine
ID - 26889
JF - Physical Review A
SN - 2469-9926
TI - Quantum optical coherence: From linear to nonlinear interferometers
ER -
TY - JOUR
AU - Lüders, Carolin
AU - Pukrop, Matthias
AU - Rozas, Elena
AU - Schneider, Christian
AU - Höfling, Sven
AU - Sperling, Jan
AU - Schumacher, Stefan
AU - Aßmann, Marc
ID - 26283
JF - PRX Quantum
SN - 2691-3399
TI - Quantifying Quantum Coherence in Polariton Condensates
ER -
TY - JOUR
AU - Bagrets, Dmitry
AU - Kim, Kun Woo
AU - Barkhofen, Sonja
AU - De, Syamsundar
AU - Sperling, Jan
AU - Silberhorn, Christine
AU - Altland, Alexander
AU - Micklitz, Tobias
ID - 26284
JF - Physical Review Research
SN - 2643-1564
TI - Probing the topological Anderson transition with quantum walks
ER -
TY - JOUR
AU - Xue, Yan
AU - Chestnov, Igor
AU - Sedov, Evgeny
AU - Kiktenko, Evgeniy
AU - Fedorov, Aleksey K.
AU - Schumacher, Stefan
AU - Ma, Xuekai
AU - Kavokin, Alexey
ID - 21362
IS - 1
JF - Physical Review Research
SN - 2643-1564
TI - Split-ring polariton condensates as macroscopic two-level quantum systems
VL - 3
ER -
TY - JOUR
AU - Jurgen von Bardeleben, Hans
AU - Cantin, Jean-Louis
AU - Gerstmann, Uwe
AU - Schmidt, Wolf Gero
AU - Biktagirov, Timur
ID - 29747
IS - 19
JF - Nano Letters
KW - Mechanical Engineering
KW - Condensed Matter Physics
KW - General Materials Science
KW - General Chemistry
KW - Bioengineering
SN - 1530-6984
TI - Spin Polarization, Electron–Phonon Coupling, and Zero-Phonon Line of the NV Center in 3C-SiC
VL - 21
ER -
TY - JOUR
AU - Slawig, Diana
AU - Gruschwitz, Markus
AU - Gerstmann, Uwe
AU - Rauls, Eva
AU - Tegenkamp, Christoph
ID - 29748
IS - 36
JF - The Journal of Physical Chemistry C
KW - Surfaces
KW - Coatings and Films
KW - Physical and Theoretical Chemistry
KW - General Energy
KW - Electronic
KW - Optical and Magnetic Materials
SN - 1932-7447
TI - Adsorption and Reaction of PbPc on Hydrogenated Epitaxial Graphene
VL - 125
ER -
TY - JOUR
AU - Jain, Mitisha
AU - Gerstmann, Uwe
AU - Schmidt, Wolf Gero
AU - Aldahhak, Hazem
ID - 40250
IS - 6
JF - Journal of Computational Chemistry
KW - Computational Mathematics
KW - General Chemistry
SN - 0192-8651
TI - Adatom mediated adsorption of N‐heterocyclic carbenes on Cu(111) and Au(111)
VL - 43
ER -
TY - JOUR
AB - High harmonic generation (HHG) from solids shows great application prospects in compact short-wavelength light sources and as a tool for imaging the dynamics in crystals with subnanometer spatial and attosecond temporal resolution. However, the underlying collision dynamics behind solid HHG is still intensively debated and no direct mapping relationship between the collision dynamics with band structure has been built. Here, we show that the electron and its associated hole can be elastically scattered by neighboring atoms when their wavelength approaches the atomic size. We reveal that the elastic scattering of electron/hole from neighboring atoms can dramatically influence the electron recombination with its left-behind hole, which turns out to be the fundamental reason for the anisotropic interband HHG observed recently in bulk crystals. Our findings link the electron/hole backward scattering with Van Hove singularities and forward scattering with critical lines in the band structure and thus build a clear mapping between the band structure and the harmonic spectrum. Our work provides a unifying picture for several seemingly unrelated experimental observations and theoretical predictions, including the anisotropic harmonic emission in MgO, the atomic-like recollision mechanism of solid HHG, and the delocalization of HHG in ZnO. This strongly improved understanding will pave the way for controlling the solid-state HHG and visualizing the structure-dependent electron dynamics in solids.
AU - Zuo, Ruixin
AU - Trautmann, Alexander
AU - Wang, Guifang
AU - Hannes, Wolf-Rüdiger
AU - Yang, Shidong
AU - Song, Xiaohong
AU - Meier, Torsten
AU - Ciappina, Marcelo
AU - Duc, Huynh Thanh
AU - Yang, Weifeng
ID - 37331
JF - Ultrafast Science
SN - 2765-8791
TI - Neighboring Atom Collisions in Solid-State High Harmonic Generation
VL - 2021
ER -
TY - JOUR
AB - AbstractMethylammonium lead iodide perovskite (MAPbI3) is renowned for an impressive power conversion efficiency rise and cost-effective fabrication for photovoltaics. In this work, we demonstrate that polycrystalline MAPbI3s undergo drastic changes in optical properties at moderate field strengths with an ultrafast response time, via transient Wannier Stark localization. The distinct band structure of this material - the large lattice periodicity, the narrow electronic energy bandwidths, and the coincidence of these two along the same high-symmetry direction – enables relatively weak fields to bring this material into the Wannier Stark regime. Its polycrystalline nature is not detrimental to the optical switching performance of the material, since the least dispersive direction of the band structure dominates the contribution to the optical response, which favors low-cost fabrication. Together with the outstanding photophysical properties of MAPbI3, this finding highlights the great potential of this material in ultrafast light modulation and novel photonic applications.
AU - Berghoff, Daniel
AU - Bühler, Johannes
AU - Bonn, Mischa
AU - Leitenstorfer, Alfred
AU - Meier, Torsten
AU - Kim, Heejae
ID - 37338
IS - 1
JF - Nature Communications
KW - General Physics and Astronomy
KW - General Biochemistry
KW - Genetics and Molecular Biology
KW - General Chemistry
KW - Multidisciplinary
SN - 2041-1723
TI - Low-field onset of Wannier-Stark localization in a polycrystalline hybrid organic inorganic perovskite
VL - 12
ER -
TY - JOUR
AU - Thong, Le Huu
AU - Ngo, Cong
AU - Duc, Huynh Thanh
AU - Song, Xiaohong
AU - Meier, Torsten
ID - 23477
JF - Physical Review B
SN - 2469-9950
TI - Microscopic analysis of high harmonic generation in semiconductors with degenerate bands
VL - 103
ER -
TY - JOUR
AB - Lithium niobate (LiNbO3), a material frequently used in optical applications, hosts different kinds of polarons that significantly affect many of its physical properties. In this study, a variety of electron polarons, namely free, bound, and bipolarons, are analyzed using first-principles calculations. We perform a full structural optimization based on density-functional theory for selected intrinsic defects with special attention to the role of symmetry-breaking distortions that lower the total energy. The cations hosting the various polarons relax to a different degree, with a larger relaxation corresponding to a larger gap between the defect level and the conduction-band edge. The projected density of states reveals that the polaron states are formerly empty Nb 4d states lowered into the band gap. Optical absorption spectra are derived within the independent-particle approximation, corrected by the GW approximation that yields a wider band gap and by including excitonic effects within the Bethe-Salpeter equation. Comparing the calculated spectra with the density of states, we find that the defect peak observed in the optical absorption stems from transitions between the defect level and a continuum of empty Nb 4d states. Signatures of polarons are further analyzed in the reflectivity and other experimentally measurable optical coefficients.
AU - Schmidt, Falko
AU - Kozub, Agnieszka L.
AU - Gerstmann, Uwe
AU - Schmidt, Wolf Gero
AU - Schindlmayr, Arno
ID - 21946
JF - Crystals
TI - Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response
VL - 11
ER -
TY - CONF
AB - Population/mixing-time-dependent two-dimensional coherent spectra are presented for exciton-polaritons in a microcavity. Theory based on dynamically-controlled truncation reveals coherent and incoherent contributions to the decay dynamics.
AU - Meier, Torsten
AU - Paul, Jagannath
AU - Rose, Hendrik
AU - Wahlstrand, Jared K
AU - Bristow, Alan D
ID - 43746
SN - 978-1-55752-308-2
T2 - Frontiers in Optics
TI - Coherent and incoherent contribution of population dynamics of semiconductor exciton-polaritons
ER -
TY - CONF
AU - Reichelt, Matthias
AU - Rose, Hendrik
AU - Kosarev, Alexander N.
AU - Poltavtsev, Sergey V.
AU - Bayer, Manfred
AU - Akimov, Ilya A.
AU - Schneider, Christian
AU - Kamp, Martin
AU - Höfling, Sven
AU - Meier, Torsten
ED - Betz, Markus
ED - Elezzabi, Abdulhakem Y.
ID - 23474
T2 - Ultrafast Phenomena and Nanophotonics XXV
TI - Controlling the emission time of photon echoes by optical freezing of exciton dephasing and rephasing in quantum-dot ensembles
VL - 11684
ER -
TY - JOUR
AU - Murzakhanov, F. F.
AU - Yavkin, B. V.
AU - Mamin, G. V.
AU - Orlinskii, S. B.
AU - von Bardeleben, H. J.
AU - Biktagirov, Timur
AU - Gerstmann, Uwe
AU - Soltamov, V. A.
ID - 29749
JF - Physical Review B
SN - 2469-9950
TI - Hyperfine and nuclear quadrupole splitting of the NV− ground state in 4H-SiC
VL - 103
ER -
TY - JOUR
AU - Aldahhak, Hazem
AU - Hogan, Conor
AU - Lindner, Susi
AU - Appelfeller, Stephan
AU - Eisele, Holger
AU - Schmidt, Wolf Gero
AU - Dähne, Mario
AU - Gerstmann, Uwe
AU - Franz, Martin
ID - 22010
JF - Physical Review B
SN - 2469-9950
TI - Electronic structure of the Si(111)3×3R30∘−B surface from theory and photoemission spectroscopy
VL - 103
ER -
TY - JOUR
AU - Rose, Hendrik
AU - Popolitova, D. V.
AU - Tikhonova, O. V.
AU - Meier, Torsten
AU - Sharapova, Polina
ID - 23478
JF - Physical Review A
SN - 2469-9926
TI - Dark-state and loss-induced phenomena in the quantum-optical regime of Λ-type three-level systems
VL - 103
ER -
TY - JOUR
AU - Belobo, Didier Belobo
AU - Meier, Torsten
ID - 23473
JF - New Journal of Physics
SN - 1367-2630
TI - Approximate nonlinear wave solutions of the coupled two-component Gross–Pitaevskii equations with spin–orbit interaction
VL - 23
ER -
TY - JOUR
AU - Nguyen, T. T. Nhung
AU - Sollfrank, T.
AU - Tegenkamp, C.
AU - Rauls, E.
AU - Gerstmann, Uwe
ID - 22881
JF - Physical Review B
SN - 2469-9950
TI - Impact of screening and relaxation on weakly coupled two-dimensional heterostructures
VL - 103
ER -
TY - JOUR
AB - Modern forming processes often allow today the efficient production of complex parts. In order to increase the sustainability of forming processes it would be favorable if the forming of workpieces becomes possible using production waste. At the Chair of Forming and Machining Technology of the Paderborn University (LUF) research is presently conducted with the overall goal to produce workpieces directly from secondary aluminum (e.g., powder and chips). Therefore, friction-based forming processes like friction spinning (or cognate processes) are used due to their high efficiency. As a pre-step, the production of semi-finished parts was the subject of accorded research work at the LUF. Therefore, a friction-based hot extrusion process was used for the full recycling or rework of aluminum chips into profiles. Investigations of the recycled semi-finished products show that they are comparable to conventionally produced semi-finished products in terms of dimensional stability and shape accuracy. An analysis of the mechanical properties of hardness and tensile strength shows that a final product with good and homogeneously distributed properties can be produced. Furthermore, significant correlations to the friction spinning process could be found that are useful for the above-mentioned direct part production from secondary aluminum.
AU - Borgert, Thomas
AU - Homberg, Werner
ID - 21635
JF - Metals
SN - 2075-4701
TI - Friction-Induced Recycling Process for User-Specific Semi-Finished Product Production
ER -
TY - CONF
AU - Moritzer, Elmar
AU - Flachmann, Felix
ID - 23746
SN - 978-1-7138-3075-7
T2 - SPE ANTEC 2021: The Annual Technical Conference for Plastic Professionals
TI - Influence of Chemical Blowing Agents on the Filling Behavior of Wood-Plastic-Composite Melts
ER -
TY - JOUR
AU - Bolenz, Lukas
AU - Ehlert, Thomas
AU - Dechert, Christopher
AU - Bertling, René
AU - Kenig, Eugeny
ID - 23789
JF - Chemical Engineering Research and Design
SN - 0263-8762
TI - Modelling of a continuous distillation process with finite reflux ratio using the hydrodynamic analogy approach
ER -
TY - CONF
AB - Driven by the CO2-emission law by the European government and the increasing costs for raw materials as well as energy, the automotive industry is increasingly using multi-material constructions. This leads to a continuous increase in the use of mechanical joining techniques and especially the self-piercing riveting is of particular importance. The reason for this is the wide range of joining possibilities as well as the high load-bearing capacities of the joints. To be able to react to changing boundary conditions, like material thickness or strength variation of the sheets, research work is crucial with regard to the increase of versatility. In this paper, a numerical study of the influences on the selfpiercing riveting process is presented. For this purpose, the influence of different process parameters such as rivet length and die depth on various quality-relevant characteristics were investigated. With the help of the design of experiment, significant influences were determined and interactions between the individual parameters are shown.
AU - Kappe, Fabian
AU - Bielak, Christian Roman
AU - Sartisson, Vadim
AU - Bobbert, Mathias
AU - Meschut, Gerson
ID - 34222
T2 - ESAFORM 2021
TI - Influence of rivet length on joint formation on self-piercing riveting process considering further process parameters
ER -
TY - CONF
AB - In many areas of product manufacturing constructions consist of individual components and metal sheets that are joined together to form complex structures. A simple and industrial common method for joining dissimilar and coated materials is clinching. During the joining process and due to the service load cracks can occur in the area of the joint, propagate due to cyclic loading and consequently lead to structural failure. For the prevention of these damage cases, first of all knowledge about the fracture mechanical material parameters regarding the original material state of the sheet metals used within the clinching process are essential.Within the scope of this paper experimental and numerical preliminary investigations regarding the fracture mechanical behavior of sheet metals used within the clinching process are presented. Due to the low thickness of 1.5 mm of the material sheets, the development of a new specimen is necessary to determine the crack growth rate curve including the fracture mechanical parameters like the threshold against crack growth ΔKI,th and the fracture toughness KIC of the base material HCT590X. For the experimental determination of the crack growth rate curve the numerical calculation of the geometry factor function as well as the calibration function of this special specimen are essential. After the experimental validation of the numerically determined calibration function, crack growth rate curves are determined for the stress ratios R = 0.1 and R = 0.3 to examine the mean stress sensitivity. In addition, the different rolling directions of 0° and 90° in relation to the initial crack are taken into account in order to investigate the influence of the anisotropy due to rolling.
AU - Weiß, Deborah
AU - Schramm, Britta
AU - Kullmer, Gunter
ID - 30675
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
SN - 1662-9795
T2 - Key Engineering Materials
TI - Numerical and Experimental Fracture Mechanical Investigations of Clinchable Sheet Metals Made of HCT590X
VL - 883
ER -
TY - JOUR
AB - AbstractIn addition to the classical strength calculation, it is important to design components with regard to fracture mechanics because defects and cracks in a component can drastically influence its strength or fatigue behavior. Cracks can propagate due to operational loads and consequently lead to component failure. The fracture mechanical analysis provides information on stable or unstable crack growth as well as about the direction and the growth rate of a crack. For this purpose, sufficient information has to be available about the crack location, the crack length, the component geometry, the component loading and the fracture mechanical material parameters. The fracture mechanical properties are determined experimentally with standardized specimens as defined by the guidelines of the American Society for Testing and Materials. In practice, however, especially in the context with damage cases or formed material fracture mechanical parameters directly for a component are of interest. However, standard specimens often cannot be extracted at all due to the complexity of the component geometry. Therefore, the development of special specimens is required whereby certain arrangements have to be made in advance. These arrangements are presented in the present paper in order to contribute to a holistic investigation chain for the experimental determination of fracture mechanical material parameters with special specimens.
AU - Weiß, Deborah
AU - Schramm, Britta
AU - Kullmer, Gunter
ID - 30674
JF - Production Engineering
KW - Industrial and Manufacturing Engineering
KW - Mechanical Engineering
SN - 0944-6524
TI - Holistic investigation chain for the experimental determination of fracture mechanical material parameters with special specimens
ER -
TY - JOUR
AB - Powder X-ray diffraction (XRD) patterns of ordered mesoporous CMK-8 and CMK-9 carbon materials are simulated by geometric modeling. The materials are amorphous at the atomic length scale but exhibit highly symmetric gyroidal structures at the nanometer scale, corresponding to regular, continuous nanopore systems with cubic symmetry. Their structures lead to characteristic low-angle XRD signatures. We introduce a model based on geometrical considerations to simulate CMK-8 and CMK-9 structures with variable volume fraction of carbon (vs. pore volume, i.e., variable 'pore wall thickness'). In addition, we also simulate carbon materials with variable amounts of guest species (e.g., sulfur) residing in their pores. The corresponding XRD patterns are calculated. The carbon volume fraction turns out to have a significant impact on the relative diffraction peak intensities, especially in case of CMK-9 carbon that features a bimodal porosity. Likewise, the presence of guest species in the pores may also strongly affect the relative peak intensities. Our study suggests that careful evaluation of experimental low-angle XRD patterns of (real) CMK-8 or CMK-9 materials offers an opportunity to obtain detailed information about the nanostructural properties in addition to the mere identification of the pore systems geometry.
AU - Schwind, Bertram
AU - Smått, Jan-Henrik
AU - Tiemann, Michael
AU - Weinberger, Christian
ID - 25894
JF - Microporous and Mesoporous Materials
SN - 1387-1811
TI - Modeling of gyroidal mesoporous CMK-8 and CMK-9 carbon nanostructures and their X-Ray diffraction patterns
ER -
TY - JOUR
AB - A comparison of infrared spectroscopic analytical approaches was made in order to assess their applicability for internal structure characterization of SiO2 thin films. Markers for porosity and/or disorder based on the analysis of the asymmetric stretching absorption band of SiO2 between 900−1350 cm−1 were discussed. The shape of this band, which shows a well-defined LO–TO splitting, depends not only on the inherent characteristics of the film under analysis but also on the particular geometry of the IR experiment and the specific surface selection rules of the substrate. Three types of SiO2 thin films with clearly defined porosity ranging from dense films to mesoporous films were investigated by transmission (at different incidence angles), direct specular reflection (at different angles), and diffuse reflection. Two different types of substrate, metallic and semiconducting, were used. The combined effect of substrate and specific technique in the final shape of the band, was discussed, and the efficacy for their applicability to the determination of porosity in thin SiO2 films was critically evaluated.
AU - de los Arcos, Teresa
AU - Müller, Hendrik
AU - Wang, Fuzeng
AU - Damerla, Varun Raj
AU - Hoppe, Christian
AU - Weinberger, Christian
AU - Tiemann, Michael
AU - Grundmeier, Guido
ID - 25897
JF - Vibrational Spectroscopy
SN - 0924-2031
TI - Review of infrared spectroscopy techniques for the determination of internal structure in thin SiO2 films
ER -
TY - THES
AU - Olenberg, Alexander
ID - 42812
SN - 9783843947855
TI - Untersuchung und Optimierung von strukturierten Packungen mittels CFD-Simulationen
ER -
TY - JOUR
AB - Tailor-made ordered mesoporous materials bear great potential in numerous fields of application where large interfaces are required. However, the inherent surfacechemical properties of conventional materials, such as silica, carbon or organosilica, poses some limitations with respect to their application. Surface manipulation by functionalization with chemically more reactive groups is one way to improve materials for their desired purpose. Another approach is the design of high surface-area composite materials. The surface manipulation, either by functionalization or by introducing guest species, can be performed selectively. This means that when several distinct, i.e. , hierarchical, types of surfaces or pore systems exist in a material, each of them may be chosen for manipulation. Several strategies can be identified to achieve this goal. Molecules or molecule assemblies can be utilized to temporarily protect pores or surfaces (soft protection), while manipulation occurs at the accessible sites. This approach is a recurring motive in this review and can also be applied to rigid template matrices (hard protection). Furthermore, the size of functionalization agents (size protection) and their reactivity/diffusion (kinetic protection) into the pores can also be utilized to achieve selectivity. In addition, challenges in the synthesis and characterization of selectively manipulated ordered mesoporous materials are discussed.
AU - Tiemann, Michael
AU - Weinberger, Christian
ID - 25893
JF - Advanced Materials Interfaces
SN - 2196-7350
TI - Selective Modification of Hierarchical Pores and Surfaces in Nanoporous Materials
ER -
TY - JOUR
AU - Fuchs, Christian
ID - 41431
IS - 1
JF - tripleC: Communication, Capitalism & Critique
TI - Engels@200: Friedrich Engels in the Age of Digital Capitalism
VL - 19
ER -
TY - JOUR
AU - Fuchs, Christian
AU - Dyer-Witheford, Nick
ID - 41599
JF - 国际社会科学杂志 (Journal of International Social Sciences) 2021 (9)
TI - 卡尔·马克思与互联网研究
ER -
TY - JOUR
AB - In this report, a flame spray pyrolysis setup has been examined with various in situ extraction methods of particle samples along the flame axis. First, two precursor formulations leading to the formation of iron oxide nanoparticles were used in a standardized SpraySyn burner system, and the final particle outcome was characterized by a broad range of established powder characterization techniques (TEM/HRTEM, SAXS, XRD, BET). The characterization of the powder products evidenced that mostly homogeneous gas-to-particle conversion takes place when applying an acidic precursor solution, whereas the absence of the acid leads to a dominant droplet-to-particle pathway. Our study indicates that a droplet-to-particle-pathway could be present even when processing the acidic formulation. However, even if a secondary pathway might take place in this case as well, it is not dominant and nearly negligible. Subsequently, the in situ particle structure evolution was investigated for the dominant gas-to-particle pathway, and particles were extracted along the flame axis for online SMPS and offline TEM/HRTEM analysis. Due to the highly reactive conditions within the flame (high temperatures, turbulent flow field, high particle number concentrations), the extraction of representative samples from spray flames is challenging. In order to handle the reactive conditions, two extraction techniques were tailored in this report. To extract an aerosol sample within the flame for SMPS measurement, a Hole in a Tube probe was adjusted. Thus, the mobility particle diameter as well as the corresponding distribution widths were obtained at different heights above the burner along the flame axis. For TEM/HRTEM image analysis, particle samples were collected thermophoretically by means of a tailored shutter system. Since all sampling grids were protected until reaching the flame axis and due to the low sampling time, momentary captures of local particle structures could be extracted precisely. The particle morphologies have clearly shown an evolution from spherical and paired particles in the flame center to fractal and compact agglomerates at later synthesis stages.
AU - Tischendorf, R.
AU - Simmler, M.
AU - Weinberger, Christian
AU - Bieber, M.
AU - Reddemann, M.
AU - Fröde, F.
AU - Lindner, J.
AU - Pitsch, H.
AU - Kneer, R.
AU - Tiemann, Michael
AU - Nirschl, H.
AU - Schmid, H.-J.
ID - 25896
JF - Journal of Aerosol Science
SN - 0021-8502
TI - Examination of the evolution of iron oxide nanoparticles in flame spray pyrolysis by tailored in situ particle sampling techniques
ER -
TY - JOUR
AB - Photodynamic therapy (PDT) using TiO2 nanoparticles has become an important alternative treatment for different types of cancer due to their high photocatalytic activity and high absorption of UV-A light. To potentiate this treatment, we have coated commercial glass plates with TiO2 nanoparticles prepared by the sol–gel method (TiO2-m), which exhibit a remarkable selectivity for the irreversible trapping of cancer cells. The physicochemical properties of the deposited TiO2-m nanoparticle coatings have been characterized by a number of complementary surface-analytical techniques and their interaction with leukemia and healthy blood cells were investigated. Scanning electron and atomic force microscopy verify the formation of a compact layer of TiO2-m nanoparticles. The particles are predominantly in the anatase phase and have hydroxyl-terminated surfaces as revealed by Raman, X-ray photoelectron, and infrared spectroscopy, as well as X-ray diffraction. We find that lymphoblastic leukemia cells adhere to the TiO2-m coating and undergo amoeboid-like migration, whereas lymphocytic cells show distinctly weaker interactions with the coating. This evidences the potential of this nanomaterial coating to selectively trap cancer cells and renders it a promising candidate for the development of future prototypes of PDT devices for the treatment of leukemia and other types of cancers with non-adherent cells.
AU - Garcia Diosa, Jaime Andres
AU - Gonzalez Orive, Alejandro
AU - Weinberger, Christian
AU - Schwiderek, Sabrina
AU - Knust, Steffen
AU - Tiemann, Michael
AU - Grundmeier, Guido
AU - Keller, Adrian
AU - Camargo Amado, Ruben Jesus
ID - 22635
JF - Journal of Biomedical Materials Research Part B: Applied Biomaterials
SN - 1552-4973
TI - TiO2 nanoparticle coatings on glass surfaces for the selective trapping of leukemia cells from peripheral blood
VL - 109
ER -
TY - JOUR
AB - The tetratopic linker 1,1,2,2-tetrakis(4-phosphonophenyl)ethylene (H8TPPE) was used to synthesize the three new porous metal–organic frameworks of composition [M2(H2O)2(H2TPPE)]·xH2O (M = Al3+, Ga3+, Fe3+), denoted as M-CAU-53 under hydrothermal reaction conditions, using the corresponding metal nitrates as starting materials. The crystal structures of the compounds were determined ab initio from powder X-ray diffraction data, revealing small structural differences. Proton conductivity measurements were carried out, indicating different conductivity mechanisms. The differences in proton conductivity could be linked to the individual structures. In addition, a thorough characterization via thermogravimetry, elemental analysis, IR-spectroscopy as well as N2- and H2O-sorption is given.
AU - Steinke, Felix
AU - Javed, Ali
AU - Wöhlbrandt, Stephan
AU - Tiemann, Michael
AU - Stock, Norbert
ID - 25892
JF - Dalton Transactions
SN - 1477-9226
TI - New isoreticular phosphonate MOFs based on a tetratopic linker
ER -
TY - CHAP
AU - Eickelmann, Birgit
ID - 29061
T2 - Chancen denken. Impulse für eine offene und mutige Gesellschaft im 21. Jahrhundert
TI - Etwas anarchischer, freier, ungewohnter (Ein Gespräch mit Birgit Eickelmann)
ER -
TY - CHAP
AU - Eickelmann, Birgit
AU - Maaz, Kai
ED - Maaz, Kai
ED - Becker-Mrotzek, Michael
ID - 29062
T2 - Schule weiter denken
TI - Ungleichheiten im Bildungssystem – eine unangenehme Konstante. Sinnvolle Maßnahmen und die Grenzen des Möglichen
ER -
TY - GEN
AU - Bonanati, Sabrina
AU - Buhl, Heike M.
AU - Eickelmann, Birgit
ID - 29066
TI - Wie Lernen in digitalen Lernumgebungen motivieren kann – Stichwort: Gamification
ER -
TY - JOUR
AB - Abstract
Objective
External focus (EF) of attention leads to improved balance performance. Consideration of the neuromodulatory effects of EF may inform its clinical utility in addressing neuroplastic impairments after musculoskeletal injuries. We aimed to determine whether electrocortical activity and balance performance changed with attentional foci that prioritized differing sensory feedback and whether changes in electrocortical activity and balance were associated.
Methods
Individuals who were healthy (n = 15) performed a single-limb balance task under 3 conditions: internal focus (IF), somatosensory focus [EF with a baton (EF-baton)], and visual focus [EF with a laser (EF-laser)]. Electrocortical activity and postural sway were recorded concurrently using electroencephalography and a triaxial force plate. Electroencephalographic signals were decomposed, localized, and clustered to generate power spectral density in θ and α-2 frequency bands. Postural sway signals were analyzed with center-of-pressure sway metrics (eg, area, distance, velocity) and knee angle. The relationship between percent change in clustered brain activity and task performance metrics was assessed.
Results
Both EF conditions resulted in increased cortical activity and improved balance performance compared to IF. EF-laser had the largest effect, demonstrating increased frontal θ power (d = 0.64), decreased central θ power (d = −0.30), and decreased bilateral motor, bilateral parietal, and occipital α-2 power (d = −1.38 to −4.27) as well as a shorter path distance (d = −0.94) and a deeper (d = 0.70) and less variable (d = −1.15) knee angle than IF. Weak to moderate associations exist between increases in cortical activity and improved balance performance (ρ = 0.405–0.584).
Conclusions
EF resulted in increased cortical activity associated with cognitive, motor, somatosensory, and visual processing. EF-laser, which prioritized visual feedback, had the largest and broadest effects. Changes in cortical activity resulting from EF were independently associated with improved balance performance.
Impact
This study demonstrates that goal-oriented attention results in functional increases in brain activity compared to internally directed self-focus. These results suggest EF may target neurophysiologic impairments and improve balance in clinical populations.
AU - Sherman, David A
AU - Lehmann, Tim
AU - Baumeister, Jochen
AU - Gokeler, Alli
AU - Donovan, Luke
AU - Norte, Grant E
ID - 34024
JF - Physical Therapy
KW - Physical Therapy
KW - Sports Therapy and Rehabilitation
SN - 0031-9023
TI - External Focus of Attention Influences Cortical Activity Associated with Single Limb Balance Performance
ER -
TY - JOUR
AB - Whereas initial findings have already identified cortical patterns accompanying proprioceptive deficiencies in patients after anterior cruciate ligament reconstruction (ACLR), little is known about compensatory sensorimotor mechanisms for re-establishing postural control. Therefore, the aim of the present study was to explore leg dependent patterns of cortical contributions to postural control in patients 6 weeks following ACLR. A total of 12 patients after ACLR (25.1 ± 3.2 years, 178.1 ± 9.7 cm, 77.5 ± 14.4 kg) and another 12 gender, age, and activity matched healthy controls participated in this study. All subjects performed 10 × 30 s. single leg stances on each leg, equipped with 64-channel mobile electroencephalography (EEG). Postural stability was quantified by area of sway and sway velocity. Estimations of the weighted phase lag index were conducted as a cortical measure of functional connectivity. The findings showed significant group × leg interactions for increased functional connectivity in the anterior cruciate ligament (ACL) injured leg, predominantly including fronto−parietal [F(1, 22) = 8.41, p ≤ 0.008, η2 = 0.28], fronto−occipital [F(1, 22) = 4.43, p ≤ 0.047, η2 = 0.17], parieto−motor [F(1, 22) = 10.30, p ≤ 0.004, η2 = 0.32], occipito−motor [F(1, 22) = 5.21, p ≤ 0.032, η2 = 0.19], and occipito−parietal [F(1, 22) = 4.60, p ≤ 0.043, η2 = 0.17] intra−hemispherical connections in the contralateral hemisphere and occipito−motor [F(1, 22) = 7.33, p ≤ 0.013, η2 = 0.25] on the ipsilateral hemisphere to the injured leg. Higher functional connectivity in patients after ACLR, attained by increased emphasis of functional connections incorporating the somatosensory and visual areas, may serve as a compensatory mechanism to control postural stability of the injured leg in the early phase of rehabilitation. These preliminary results may help to develop new neurophysiological assessments for detecting functional deficiencies after ACLR in the future.
AU - Lehmann, Tim
AU - Büchel, Daniel
AU - Mouton, Caroline
AU - Gokeler, Alli
AU - Seil, Romain
AU - Baumeister, Jochen
ID - 32434
JF - Frontiers in Human Neuroscience
KW - Behavioral Neuroscience
KW - Biological Psychiatry
KW - Psychiatry and Mental health
KW - Neurology
KW - Neuropsychology and Physiological Psychology
SN - 1662-5161
TI - Functional Cortical Connectivity Related to Postural Control in Patients Six Weeks After Anterior Cruciate Ligament Reconstruction
VL - 15
ER -
TY - JOUR
AB - Abstract Mobile Electroencephalography (EEG) provides insights into cortical contributions to postural control. Although changes in theta (4–8 Hz) and alpha frequency power (8–12 Hz) were shown to reflect attentional and sensorimotor processing during balance tasks, information about the effect of stance leg on cortical processing related to postural control is lacking. Therefore, the aim was to examine patterns of cortical activity during single-leg stance with varying surface stability. EEG and force plate data from 21 healthy males (22.43 ± 2.23 years) was recorded during unipedal stance (left/right) on a stable and unstable surface. Using source-space analysis, power spectral density was analyzed in the theta, alpha-1 (8–10 Hz) and alpha-2 (10–12 Hz) frequency bands. Repeated measures ANOVA with the factors leg and surface stability revealed significant interaction effects in the left (p = 0.045, ηp2 = 0.13) and right motor clusters (F = 16.156; p = 0.001, ηp2 = 0.41). Furthermore, significant main effects for surface stability were observed for the fronto-central cluster (theta), left and right motor (alpha-1), as well as for the right parieto-occipital cluster (alpha-1/alpha-2). Leg dependent changes in alpha-2 power may indicate lateralized patterns of cortical processing in motor areas during single-leg stance. Future studies may therefore consider lateralized patterns of cortical activity for the interpretation of postural deficiencies in unilateral lower limb injuries.
AU - Büchel, Daniel
AU - Lehmann, Tim
AU - Ullrich, Sarah
AU - Cockcroft, John
AU - Louw, Quinette
AU - Baumeister, Jochen
ID - 32435
IS - 4
JF - Experimental Brain Research
KW - General Neuroscience
SN - 0014-4819
TI - Stance leg and surface stability modulate cortical activity during human single leg stance
VL - 239
ER -
TY - JOUR
AU - Büchel, Daniel
AU - Lehmann, Tim
AU - Sandbakk, Øyvind
AU - Baumeister, Jochen
ID - 35626
IS - 1
JF - Scientific Reports
KW - Multidisciplinary
SN - 2045-2322
TI - EEG‑derived brain graphs are reliable measures for exploring exercise‑induced changes in brain networks
VL - 11
ER -
TY - GEN
AU - Neukötter, Moritz
AU - Jesinghausen, Steffen
AU - Schmid, Hans-Joachim
ID - 24475
TI - Theoretische Beschreibung des Tropfenbildungsprozesses bei der Filament Extension Atomization: Entwicklung eines Vorhersagemodells für die Tropfengröße (Poster)
ER -
TY - GEN
AU - Neukötter, Moritz
AU - Jesinghausen, Steffen
AU - Schmid, Hans-Joachim
ID - 30221
TI - Filament Extension Atomization – A novel Process for Powder Production? (Presentation)
ER -
TY - JOUR
AU - Möhring, Julia
AU - Krumhöfner, Anika
AU - Gräfin von Plettenberg, Elisabeth Gudila Sophia Ida Maria
ID - 43016
JF - -
TI - Bewegungsförderung in Ganztagsschulen
ER -
TY - GEN
AU - Leineweber, Jonas
ID - 33210
TI - Veranstaltungsbericht: Immaterielles Kulturerbe in Nordrhein-Westfalen – Steigerlied und Trinkhallenkultur im Ruhrgebiet erhalten Auszeichnung anlässlich der Neuaufnahmen in das nordrhein-westfälische Landesinventar
ER -
TY - GEN
AU - Leineweber, Jonas
ID - 33209
TI - Tagungsbericht: Immaterielles Kulturerbe und regionale Identität. Gesellschaftliche Repräsentation und Partizipation im Schützenwesen
ER -
TY - JOUR
AB - Zinc oxide nanoparticles (ZnO NP) used for the channel region in inverted coplanar setup in Thin Film Transistors (TFT) were the focus of this study. The regions between the source electrode and the ZnO NP and the drain electrode were under investigation as they produce a Schottky barrier in metal-semiconductor interfaces. A more general Thermionic emission theory must be evaluated: one that considers both metal/semiconductor interfaces (MSM structures). Aluminum, gold, and nickel were used as metallization layers for source and drain electrodes. An organic-inorganic nanocomposite was used as a gate dielectric. The TFTs transfer and output characteristics curves were extracted, and a numerical computational program was used for fitting the data; hence information about Schottky Barrier Height (SBH) and ideality factors for each TFT could be estimated. The nickel metallization appears with the lowest SBH among the metals investigated. For this metal and for higher drain-to-source voltages, the SBH tended to converge to some value around 0.3 eV. The developed fitting method showed good fitting accuracy even when the metallization produced different SBH in each metal-semiconductor interface, as was the case for gold metallization. The Schottky effect is also present and was studied when the drain-to-source voltages and/or the gate voltage were increased.
AU - Kaufmann, Ivan Rodrigo
AU - Zerey, Onur
AU - Meyers, Thorsten
AU - Reker, Julia
AU - Vidor, Fábio
AU - Hilleringmann, Ulrich
ID - 39383
IS - 5
JF - Nanomaterials
KW - General Materials Science
KW - General Chemical Engineering
SN - 2079-4991
TI - A Study about Schottky Barrier Height and Ideality Factor in Thin Film Transistors with Metal/Zinc Oxide Nanoparticles Structures Aiming Flexible Electronics Application
VL - 11
ER -
TY - CONF
AU - Reker, Julia
AU - Meyers, Thorsten
AU - Vidor, Fabio F.
AU - Joubert, Trudi-Heleen
AU - Hilleringmann, Ulrich
ID - 39395
T2 - 2021 Smart Systems Integration (SSI)
TI - Complementary Inverter Circuits on Flexible Substrates
ER -
TY - CONF
AU - Hilleringmann, Ulrich
AU - Petrov, Dmitry
AU - Mwammenywa, Ibrahim
AU - Kagarura, Geoffrey M.
ID - 39381
T2 - 2021 IEEE AFRICON
TI - Local Power Control using Wireless Sensor System for Microgrids in Africa
ER -
TY - CONF
AU - Andrews, George
AU - Hilleringmann, Ulrich
AU - Joubert, Trudi-Heleen
ID - 39385
T2 - 2021 IEEE AFRICON
TI - The Viability of a Non-Flow Capacitive Biosensing Microsystem for Whole Cell Counting
ER -
TY - CONF
AU - Andrews, George
AU - Hilleringmann, Ulrich
AU - Joubert, Trudi-Heleen
ID - 39386
T2 - 2021 IEEE AFRICON
TI - The Viability of a Non-Flow Capacitive Biosensing Microsystem for Whole Cell Counting
ER -
TY - CHAP
AU - Gerhardts, Lara
AU - Dehmel, Lukas
AU - Meister, Dorothee M.
ED - Wolf, Karsten D
ED - Rummler, Klaus
ED - Bettinger, Patrick
ED - Aßmann, Sandra
ID - 43143
T2 - Jahrbuch Medienpädagogik 16. Medienpädagogik in Zeiten einer tiefgreifenden Mediatisierung
TI - Die berufliche Tabletaneignung von Lehrkräften als Beispiel der Mediatisierung pädagogischer Handlungskontexte. Theoretische Perspektiven und empirische Befunde
ER -
TY - CHAP
AU - Dehmel, Lukas
ED - Bernhard-Skala,, Christian
ED - Bolten-Bühler, Ricarda
ED - Koller, Julia
ED - Rohs, Matthias
ED - Wahl, Johannes
ID - 43142
T2 - Erwachsenenpädagogische Digitalisierungsforschung. Impulse - Befunde - Perspektiven. Bielefeld
TI - Zur Entgrenzung der Arbeit des medienpädagogischen Weiterbildungspersonals im Kontext tiefgreifender Mediatisierung
ER -
TY - JOUR
AU - Hälterlein, Jens
ID - 43278
IS - 1
JF - Big Data & Society
TI - Epistemologies of predictive policing: Mathematical social science, social physics and machine learning
VL - 8
ER -
TY - JOUR
AB - Let E be an ordinary elliptic curve over a finite field and g be a positive integer. Under some technical assumptions, we give an algorithm to span the isomorphism classes of principally polarized abelian varieties in the isogeny class of E⁹ . The varieties are first described as hermitian lattices over (not necessarily maximal) quadratic orders and then geometrically in terms of their algebraic theta null point. We also show how to algebraically compute Siegel modular forms of even weight given as polynomials in the theta constants by a careful choice of an affine lift of the theta null point. We then use these results to give an algebraic computation of Serre’s obstruction for principally polarized abelian threefolds isogenous to E³ and of the Igusa modular form in dimension 4. We illustrate our algorithms with examples of curves with many rational points over finite fields.
AU - Kirschmer, Markus
AU - Narbonne, Fabien
AU - Ritzenthaler, Christophe
AU - Robert, Damien
ID - 34912
IS - 333
JF - Mathematics of Computation
KW - Applied Mathematics
KW - Computational Mathematics
KW - Algebra and Number Theory
SN - 0025-5718
TI - Spanning the isogeny class of a power of an elliptic curve
VL - 91
ER -
TY - GEN
AU - Schroeter-Wittke, Harald
ID - 41088
SN - 0540–6226
T2 - Jahrbuch für Evangelische Kirchengeschichte des Rheinlandes
TI - Anette Baumann / Alexander Jendorff / Frank Theisen (Hgg.), Religion – Migration – Integration. Studien zu Wechselwirkungen religiös motivierter Mobilität im vormodernen Europa, Tübingen 2019
VL - 70
ER -
TY - GEN
AU - Schroeter-Wittke, Harald
ID - 41090
SN - 0540–6226
T2 - Jahrbuch für Evangelische Kirchengeschichte des Rheinlandes
TI - Hendrik Meyer-Magister, Wehrdienst und Verweigerung als komplementäres Handeln. Individualisierungsprozesse im bundesdeutschen Protestantismus der 1950er Jahre (RBRD 7), Tübingen 2019
VL - 70
ER -
TY - GEN
AU - Schroeter-Wittke, Harald
ID - 41091
SN - 0540–6226
T2 - Jahrbuch für Evangelische Kirchengeschichte des Rheinlandes
TI - Jutta Stander-Dulisch, Glaubenskrisen, Neue Religionen und der Papst. Religion in „Stern“ und Spiegel“ von 1960 bis 2014, Bielefeld 2019
VL - 70
ER -
TY - JOUR
AB - The relativistic wave equations determine the dynamics of quantum fields in the context of quantum field theory. One of the conventional tools for dealing with the relativistic bound state problem is the Klein-Fock-Gordon equation. In this work, using a developed scheme, we present how to surmount the centrifugal part and solve the modified Klein-Fock-Gordon equation for the linear combination of Hulthén and Yukawa potentials. In particular, we show that the relativistic energy eigenvalues and corresponding radial wave functions are obtained from supersymmetric quantum mechanics by applying the shape invariance concept. Here, both scalar potential conditions, which are whether equal and nonequal to vector potential, are considered in the calculation. The energy levels and corresponding normalized eigenfunctions are represented as a recursion relation regarding the Jacobi polynomials for arbitrary
states. Beyond that, a closed form of the normalization constant of the wave functions is found. Furthermore, we state that the energy eigenvalues are quite sensitive with potential parameters for the quantum states. The nonrelativistic and relativistic results obtained within SUSY QM overlap entirely with the results obtained by ordinary quantum mechanics, and it displays that the mathematical implementation of SUSY quantum mechanics is quite perfect.
AU - Ahmadov, A. I.
AU - Aslanova, S. M.
AU - Orujova, M. Sh.
AU - Badalov, S. V.
ED - Vagnozzi, Sunny
ID - 44042
JF - Advances in High Energy Physics
KW - Nuclear and High Energy Physics
SN - 1687-7365
TI - Analytical Bound State Solutions of the Klein-Fock-Gordon Equation for the Sum of Hulthén and Yukawa Potential within SUSY Quantum Mechanics
VL - 2021
ER -
TY - CONF
AU - Meydani, Elnaz
AU - Düsing, Christoph
AU - Trier, Matthias
ID - 44073
T2 - Innovation Through Information Systems: Volume II: A Collection of Latest Research on Technology Issues
TI - Towards a Trust-Aware Item Recommendation System on a Graph Autoencoder with Attention Mechanism
ER -
TY - JOUR
AU - Neufeld, Sergej
AU - Bocchini, Adriana
AU - Schmidt, Wolf Gero
ID - 22310
JF - Physical Review Materials
SN - 2475-9953
TI - Potassium titanyl phosphate Z- and Y-cut surfaces from density-functional theory
ER -
TY - JOUR
AU - Plaickner, Julian
AU - Speiser, Eugen
AU - Braun, Christian
AU - Schmidt, Wolf Gero
AU - Esser, Norbert
AU - Sanna, Simone
ID - 22008
JF - Physical Review B
SN - 2469-9950
TI - Surface localized phonon modes at the Si(553)-Au nanowire system
ER -
TY - JOUR
AU - Meier, Lukas
AU - Schmidt, Wolf Gero
ID - 40244
IS - 1
JF - physica status solidi (b)
KW - Condensed Matter Physics
KW - Electronic
KW - Optical and Magnetic Materials
SN - 0370-1972
TI - GaInP/AlInP(001) Interfaces from Density Functional Theory
VL - 259
ER -
TY - JOUR
AU - Ruiz Alvarado, Isaac Azahel
AU - Karmo, Marsel
AU - Runge, Erich
AU - Schmidt, Wolf Gero
ID - 22009
JF - ACS Omega
SN - 2470-1343
TI - InP and AlInP(001)(2 × 4) Surface Oxidation from Density Functional Theory
ER -
TY - JOUR
AB - We perform a theoretical analysis of the structural and electronic properties of sodium potassium niobate K1-xNaxNbO3 in the orthorhombic room-temperature phase, based on density-functional theory in combination with the supercell approach. Our results for x=0 and x=0.5 are in very good agreement with experimental measurements and establish that the lattice parameters decrease linearly with increasing Na contents, disproving earlier theoretical studies based on the virtual-crystal approximation that claimed a highly nonlinear behavior with a significant structural distortion and volume reduction in K0.5Na0.5NbO3 compared to both end members of the solid solution. Furthermore, we find that the electronic band gap varies very little between x=0 and x=0.5, reflecting the small changes in the lattice parameters.
AU - Bidaraguppe Ramesh, Nithin
AU - Schmidt, Falko
AU - Schindlmayr, Arno
ID - 22960
IS - 8
JF - The European Physical Journal B
SN - 1434-6028
TI - Lattice parameters and electronic band gap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory
VL - 94
ER -
TY - JOUR
AU - Friedrich, Christoph
AU - Blügel, Stefan
AU - Schindlmayr, Arno
ID - 22761
IS - 3
JF - Physical Review B
SN - 2469-9950
TI - Erratum: Efficient implementation of the GW approximation within the all-electron FLAPW method [Phys. Rev. B 81, 125102 (2010)]
VL - 104
ER -
TY - JOUR
AB - Uniaxial anisotropy in nonlinear birefringent crystals limits the efficiency of nonlinear optical interactions and breaks the spatial symmetry of light generated in the parametric down-conversion (PDC) process. Therefore, this effect is usually undesirable and must be compensated for. However, high gain may be used to overcome the destructive role of anisotropy in order to generate bright two-mode correlated twin-beams. In this work, we provide a rigorous theoretical description of the spatial properties of bright squeezed light in the presence of strong anisotropy. We investigate a single crystal and a system of two crystals with an air gap (corresponding to a nonlinear SU(1,1) interferometer) and demonstrate the generation of bright correlated twin-beams in such configurations at high gain due to anisotropy. We explore the mode structure of the generated light and show how anisotropy, together with crystal spacing, can be used for radiation shaping.
AU - Riabinin, M.
AU - Sharapova, Polina
AU - Meier, Torsten
ID - 37334
IS - 14
JF - Optics Express
KW - Atomic and Molecular Physics
KW - and Optics
SN - 1094-4087
TI - Bright correlated twin-beam generation and radiation shaping in high-gain parametric down-conversion with anisotropy
VL - 29
ER -
TY - JOUR
AU - Geraldi, Andrea
AU - De, Syamsundar
AU - Laneve, Alessandro
AU - Barkhofen, Sonja
AU - Sperling, Jan
AU - Mataloni, Paolo
AU - Silberhorn, Christine
ID - 26287
JF - Physical Review Research
SN - 2643-1564
TI - Transient subdiffusion via disordered quantum walks
ER -
TY - JOUR
AU - Tiedau, J.
AU - Engelkemeier, M.
AU - Brecht, Benjamin
AU - Sperling, Jan
AU - Silberhorn, Christine
ID - 21021
JF - Physical Review Letters
SN - 0031-9007
TI - Statistical Benchmarking of Scalable Photonic Quantum Systems
VL - 126
ER -
TY - JOUR
AU - Prasannan, Nidhin
AU - De, Syamsundar
AU - Barkhofen, Sonja
AU - Brecht, Benjamin
AU - Silberhorn, Christine
AU - Sperling, Jan
ID - 26286
JF - Physical Review A
SN - 2469-9926
TI - Experimental entanglement characterization of two-rebit states
VL - 103
ER -
TY - JOUR
AU - Köhnke, S.
AU - Agudelo, E.
AU - Schünemann, M.
AU - Schlettwein, O.
AU - Vogel, W.
AU - Sperling, Jan
AU - Hage, B.
ID - 26285
JF - Physical Review Letters
SN - 0031-9007
TI - Quantum Correlations beyond Entanglement and Discord
ER -