@article{47982, abstract = {{Spontaneous Raman spectroscopy (SR) is a versatile method for analysis and visualization of ferroelectric crystal structures, including domain walls. Nevertheless, the necessary acquisition time makes SR impractical for in situ analysis and large scale imaging. In this work, we introduce broadband coherent anti-Stokes Raman spectroscopy (B-CARS) as a high-speed alternative to conventional Raman techniques and demonstrate its benefits for ferroelectric domain wall analysis. Using the example of poled lithium niobate, we compare the spectral output of both techniques in terms of domain wall signatures and imaging capabilities. We extract the Raman-like resonant part of the coherent anti-Stokes signal via a Kramers–Kronig-based phase retrieval algorithm and compare the raw and phase-retrieved signals to SR characteristics. Finally, we propose a mechanism for the observed domain wall signal strength that resembles a Čerenkov-like behavior, in close analogy to domain wall signatures obtained by second-harmonic generation imaging. We, thus, lay here the foundations for future investigations on other poled ferroelectric crystals using B-CARS.}}, author = {{Reitzig, Sven and Hempel, Franz and Ratzenberger, Julius and Hegarty, Peter A. and Amber, Zeeshan H. and Buschbeck, Robin and Rüsing, Michael and Eng, Lukas M.}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, keywords = {{Physics and Astronomy (miscellaneous)}}, number = {{16}}, publisher = {{AIP Publishing}}, title = {{{High-speed hyperspectral imaging of ferroelectric domain walls using broadband coherent anti-Stokes Raman scattering}}}, doi = {{10.1063/5.0086029}}, volume = {{120}}, year = {{2022}}, } @article{47989, abstract = {{Thin-film materials from μm thickness down to single-atomic-layered 2D materials play a central role in many novel electronic and optical applications. Coherent, nonlinear optical (NLO) μ-spectroscopy offers insight into the local thickness, stacking order, symmetry, or electronic and vibrational properties. Thin films and 2D materials are usually supported on multi-layered substrates leading to (multi-)reflections, interference, or phase jumps at interfaces during μ-spectroscopy, which all can make the interpretation of experiments particularly challenging. The disentanglement of the influence parameters can be achieved via rigorous theoretical analysis. In this work, we compare two self-developed modeling approaches, a semi-analytical and a fully vectorial model, to experiments carried out in thin-film geometry for two archetypal NLO processes, second-harmonic and third-harmonic generation. In particular, we demonstrate that thin-film interference and phase matching do heavily influence the signal strength. Furthermore, we work out key differences between three and four photon processes, such as the role of the Gouy-phase shift and the focal position. Last, we can show that a relatively simple semi-analytical model, despite its limitations, is able to accurately describe experiments at a significantly lower computational cost as compared to a full vectorial modeling. This study lays the groundwork for performing quantitative NLO μ-spectroscopy on thin films and 2D materials, as it identifies and quantifies the impact of the corresponding sample and setup parameters on the NLO signal, in order to distinguish them from genuine material properties.<}}, author = {{Amber, Zeeshan H. and Spychala, Kai J. and Eng, Lukas M. and Rüsing, Michael}}, issn = {{0021-8979}}, journal = {{Journal of Applied Physics}}, keywords = {{General Physics and Astronomy}}, number = {{21}}, publisher = {{AIP Publishing}}, title = {{{Nonlinear optical interactions in focused beams and nanosized structures}}}, doi = {{10.1063/5.0125926}}, volume = {{132}}, year = {{2022}}, } @article{47988, abstract = {{Second harmonic (SH) microscopy represents a powerful tool for the investigation of crystalline systems, such as ferroelectrics and their domain walls (DWs). Under the condition of normal dispersion, i.e., the refractive index at the SH wavelength is larger as compared to the refractive index at the fundamental wavelength, n(2ω)>n(ω), bulk crystals will generate no SH signal. Should the bulk, however, contain DWs, an appreciable SH signal will still be detectable at the location of DWs stemming from the Čerenkov mechanism. In this work, we demonstrate both how SH signals are generated in bulk media and how the Čerenkov mechanism can be inhibited by using anomalous dispersion, i.e., n(ω)A new decomposition mechanism for trimethylborane at high temperatures has been discovered.}}, author = {{Schleier, Domenik and Gerlach, Marius and Schaffner, Dorothee and Mukhopadhyay, Deb Pratim and Hemberger, Patrick and Fischer, Ingo}}, issn = {{1463-9076}}, journal = {{Physical Chemistry Chemical Physics}}, keywords = {{Physical and Theoretical Chemistry, General Physics and Astronomy}}, number = {{6}}, pages = {{4511--4518}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Threshold photoelectron spectroscopy of trimethylborane and its pyrolysis products}}}, doi = {{10.1039/d2cp04513c}}, volume = {{25}}, year = {{2022}}, } @article{35322, author = {{Bux, Kai-Uwe and Hilgert, Joachim and Weich, Tobias}}, issn = {{1664-039X}}, journal = {{Journal of Spectral Theory}}, keywords = {{Geometry and Topology, Mathematical Physics, Statistical and Nonlinear Physics}}, number = {{2}}, pages = {{659--681}}, publisher = {{European Mathematical Society - EMS - Publishing House GmbH}}, title = {{{Poisson transforms for trees of bounded degree}}}, doi = {{10.4171/jst/414}}, volume = {{12}}, year = {{2022}}, } @article{36332, abstract = {{AlSi casting alloys combine excellent castability with high strength. Hence, this group of alloys is often used in the automotive sector. The challenge for this application is the brittle character of these alloys which leads to cracks during joint formation when mechanical joining technologies are used. A rise in ductility can be achieved by a considerable increase in the solidification rate which results in grain refinement. High solidification rates can be realized in twin–roll casting (TRC) by water-cooled rolls. Therefore, a hypoeutectic EN AC–AlSi9 (for European Norm - aluminum cast product) is manufactured by the TRC process and analyzed. Subsequently, joining investigations are performed on castings in as-cast and heat-treated condition using the self-piercing riveting process considering the joint formation and the load-bearing capacity. Due to the fine microstructure, the crack initiation can be avoided during joining, while maintaining the joining parameters, especially by specimens in heat treatment conditions. Furthermore, due to the extremely fine microstructure, the load-bearing capacity of the joint can be significantly increased in terms of the maximum load-bearing force and the energy absorbed.}}, author = {{Neuser, Moritz and Kappe, Fabian and Ostermeier, Jakob and Krüger, Jan Tobias and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko and Grydin, Olexandr}}, issn = {{1438-1656}}, journal = {{Advanced Engineering Materials}}, keywords = {{Condensed Matter Physics, General Materials Science}}, number = {{10}}, publisher = {{Wiley}}, title = {{{Mechanical Properties and Joinability of AlSi9 Alloy Manufactured by Twin‐Roll Casting}}}, doi = {{10.1002/adem.202200874}}, volume = {{24}}, year = {{2022}}, } @article{53080, abstract = {{Quantitative speciation data for alternative fuels is highly desired to assess their emission potential and to develop and validate chemical kinetic models. In terms of substitute choices for fossil diesel are oxymethylene ethers (OMEs) strongly discussed. Due to the absence of carbon-carbon bonds, soot emis-sions from combustion of OMEs are low, but significant emissions of unregulated pollutants such as alde-hydes emerge. The combustion behavior of OME fuels with different chain lengths, OME0-4, was investigated in lam-inar premixed low-pressure flames using complementary molecular-beam mass spectrometry (MBMS) techniques. MBMS sampling provides an in-situ access directly into the reaction zone of the flame. Al-most all chemical species involved in the oxidation process can be detected and quantified simultane-ously. Neat OME0-3 flames were analyzed by electron ionization (EI) MBMS with high mass resolution ( R approximate to 3900) providing exact elementary composition. To obtain isomer-specific information, an OME1- doped hydrogen flame and a stochiometric OME4 flame were studied by double-imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy. Both, EI-MBMS detection and i2PEPICO spectroscopy, en-ables a complete overview of all intermediates. The results show a dominance of oxygenated intermediates for all measured conditions. Mole fraction profiles for the most important species are presented (i.e. formaldehyde, methanol, methyl formate and formic acid) and compared to modeling results. Hydrocarbons with more than four carbon atoms were not detected under the investigated conditions. Isomers such as ethanol/dimethyl ether (m/z = 46) and ethenol/acetaldehyde (m/z = 44) could be separated using threshold photoelectron spectra for clear iden-tification and photoionization efficiency curves for quantification. This investigation permits the discus-sion and analysis of systematic trends, including intermediate species, for the combustion of the studied series of oxymethylene ether fuels. (c) 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.}}, author = {{Gaiser, Nina and Zhang, Hao and Bierkandt, Thomas and Schmitt, Steffen and Zinsmeister, Julia and Kathrotia, Trupti and Hemberger, Patrick and Shaqiri, Shkelqim and Kasper, Tina and Aigner, Manfred and Oßwald, Patrick and Köhler, Markus}}, issn = {{0010-2180}}, journal = {{Combustion and Flame}}, keywords = {{General Physics and Astronomy, Energy Engineering and Power Technology, Fuel Technology, General Chemical Engineering, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Investigation of the combustion chemistry in laminar, low-pressure oxymethylene ether flames (OME0–4)}}}, doi = {{10.1016/j.combustflame.2022.112060}}, volume = {{243}}, year = {{2022}}, } @article{53081, abstract = {{Recent progress in molecular combustion chemistry allows for detailed investigation of the intermediate species pool even for complex chemical fuel compositions, as occur for technical fuels. This study pro-vides detailed investigation of a comprehensive set of complex alternative gasoline fuels obtained from laminar flow reactors equipped with molecular-beam sampling techniques for observation of the com-bustion intermediate species pool in homogeneous gas phase reactions. The combination of ionization techniques including double-imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy enables deeper mechanistic insights into the underlying reaction network relevant to technical fuels. The se-lected fuels focus on contemporary automotive engine application as drop-in fuels compliant to European EN 228 specification for gasoline. Therefore, potential alternative gasoline blends containing oxygenated hydrocarbons as octane improvers obtainable from bio-technological production routes, e.g., ethanol, iso- butanol, methyl tert -butyl ether (MTBE), and ethyl tert -butyl ether (ETBE), as well as a Fischer-Tropsch surrogate were investigated. The fuel set is completed by two synthetic naphtha fractions obtained from Fischer-Tropsch and methanol-to-gasoline processes alongside with a fossil reference gasoline. In total, speciation data for 11 technical fuels from two atmospheric flow reactor setups are presented. Detailed main and intermediate species profiles are provided for slightly rich ( 4) = 1.2) and lean ( 4) = 0.8) con-ditions for intermediate to high temperatures. Complementary, the isomer distribution on different mass channels, like m/z = 78 u fulvene/benzene, of four gasolines was investigated. Experimental findings are analyzed in terms of the detailed fuel composition and literature findings for molecular combustion chemistry. Influences of oxygenated fuel components as well as composition of the hydrocarbon frac-tions are examined with a particular focus on the soot precursor chemistry. This dataset is available for validation of chemical kinetic mechanisms for realistic gasolines containing oxygenated hydrocarbons.(c) 2021 The Combustion Institute. Published by Elsevier Inc. All rights reserved.}}, author = {{Zinsmeister, Julia and Gaiser, Nina and Melder, Jens and Bierkandt, Thomas and Hemberger, Patrick and Kasper, Tina and Aigner, Manfred and Köhler, Markus and Oßwald, Patrick}}, issn = {{0010-2180}}, journal = {{Combustion and Flame}}, keywords = {{General Physics and Astronomy, Energy Engineering and Power Technology, Fuel Technology, General Chemical Engineering, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{On the diversity of fossil and alternative gasoline combustion chemistry: A comparative flow reactor study}}}, doi = {{10.1016/j.combustflame.2021.111961}}, volume = {{243}}, year = {{2022}}, } @article{35111, abstract = {{Forschendes Lernen in der Lehrer:innenbildung ist seit der Ausweitung schulpraktischer Anteile bzw. der Einführung des sogenannten Praxissemesters eng verwoben mit der Lehrer:innenausbildung. Gleichzeitig wird bisher weitestgehend different beantwortet, was Forschendes Lernen ist und sein kann sowie warum es wie hochschuldidaktisch gerahmt wird und werden sollte. Der Beitrag widmet sich dieser Frage. Dabei zeigt sich einerseits, dass hochschuldidaktische Zugänge zur Realisierung Forschenden Lernens in der Lehrer:innenbildung erst vor dem Hintergrund theoretischer Annahmen zur Entwicklung von Lehrpersonen und deren Professionalität sowie zur Gestalt - gemeint ist hier der Beitrag zu dieser Entwicklung sowie der Anteil an Professionalität - Forschenden Lernens entwickelt werden können, eine solche Fundierung aber oftmals ausbleibt. Andererseits wird herausgearbeitet, inwiefern eine Differenz zwischen wissenschaftlicher Forschung und Forschung im Forschenden Lernen besteht. Daran anschließend wird eine habitustheoretische Fundierung Forschenden Lernens vorgestellt und es werden exemplarisch deren Implikationen für die Gestaltung Forschenden Lernens benannt. Abschließend wird anhand empirischer Rekonstruktionen beispielhaft eine praktische Umsetzung diskutiert.}}, author = {{Bloh, Thiemo and Caruso, Carina}}, issn = {{2199-8825}}, journal = {{die hochschullehre}}, keywords = {{Forschendes Lernen, Lehrer:innenausbildung, Praxissemester, Professionalisierung / Research-based learning, teacher education, internships, professionalization}}, number = {{21}}, pages = {{299–312}}, publisher = {{wbv }}, title = {{{Ein kritisch-multiperspektivischer Blick auf Forschendes Lernen in der Lehrkräftebildung}}}, doi = {{10.3278/HSL2221W}}, volume = {{8}}, year = {{2022}}, } @article{53084, abstract = {{AbstractThe thermal decomposition of Zr(acac)4 is studied in a SiC-microreactor on the micro-second time scale. By utilizing synchrotron radiation and photoelectron photoion coincidence spectroscopy, six important zirconium intermediates, as for instance Zr(C5H7O2)2(C5H6O2), and Zr(C5H6O2)2, are identified in the gas phase for the first time. The adiabatic ionization thresholds of intermediately formed zirconium species are estimated and the main products of their thermal decomposition, acetylacetone, acetylallene and acetone are characterized unambiguously and isomer-selectively. Based on all detected intermediates, we deduce the predominant pyrolysis pathways of the precursor in the temperature range from 400 to 900 K. Our findings are complemented by numerical simulations of the flow field in the microreactor, which show that the choice of dilution gas significantly influences the temperature profile and residence times in the microreactor, such that helium provides a more uniform flow field than argon and should preferentially be used. Graphical abstract Using a soft ionization method coupled to velocity map imaging (VMI), leads to valuable insights in the thermal decomposition of Zr(C5H7O2)4, used in the synthesis of functional nanomaterials and ceramic coatings. Thanks to the use of a microreactor, important gas}}, author = {{Grimm, Sebastian and Baik, Seung-Jin and Hemberger, Patrick and Kasper, Tina and Kempf, Andreas M. and Atakan, Burak}}, issn = {{0884-2914}}, journal = {{Journal of Materials Research}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, number = {{9}}, pages = {{1558--1575}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Insights into the decomposition of zirconium acetylacetonate using synchrotron radiation: Routes to the formation of volatile Zr-intermediates}}}, doi = {{10.1557/s43578-022-00566-6}}, volume = {{37}}, year = {{2022}}, } @article{47552, author = {{Herrmann, Felix and Grünewald, Marcus and Riese, Julia}}, issn = {{0360-3199}}, journal = {{International Journal of Hydrogen Energy}}, keywords = {{Energy Engineering and Power Technology, Condensed Matter Physics, Fuel Technology, Renewable Energy, Sustainability and the Environment}}, number = {{25}}, pages = {{9377--9389}}, publisher = {{Elsevier BV}}, title = {{{Model-based design of a segmented reactor for the flexible operation of the methanation of CO2}}}, doi = {{10.1016/j.ijhydene.2022.12.122}}, volume = {{48}}, year = {{2022}}, } @article{36874, author = {{Su, Jiangling and González Orive, Alejandro and Grundmeier, Guido}}, issn = {{0169-4332}}, journal = {{Applied Surface Science}}, keywords = {{Surfaces, Coatings and Films, Condensed Matter Physics, Surfaces and Interfaces, General Physics and Astronomy, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Nano-FTIR and chemical force analysis of electrografted aryldiazonium salts on ODT-microcontact printed Au-surfaces}}}, doi = {{10.1016/j.apsusc.2022.155355}}, volume = {{609}}, year = {{2022}}, } @article{36872, author = {{Bobzin, K. and Kalscheuer, C. and Grundmeier, Guido and de los Arcos, T. and Kollmann, S. and Carlet, M.}}, issn = {{0257-8972}}, journal = {{Surface and Coatings Technology}}, keywords = {{Materials Chemistry, Surfaces, Coatings and Films, Surfaces and Interfaces, Condensed Matter Physics, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Oxidation stability of chromium aluminum oxynitride hard coatings}}}, doi = {{10.1016/j.surfcoat.2022.128927}}, volume = {{449}}, year = {{2022}}, } @article{36817, author = {{Hoener, Martin and Kasper, Tina}}, issn = {{0010-2180}}, journal = {{Combustion and Flame}}, keywords = {{General Physics and Astronomy, Energy Engineering and Power Technology, Fuel Technology, General Chemical Engineering, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Nitrous acid in high-pressure oxidation of CH4 doped with nitric oxide: Challenges in the isomer-selective detection and quantification of an elusive intermediate}}}, doi = {{10.1016/j.combustflame.2022.112096}}, volume = {{243}}, year = {{2022}}, } @article{35977, author = {{Hoppe, Christian and Mitschker, Felix and Mai, Lukas and Liedke, Maciej Oskar and de los Arcos de Pedro, Maria Teresa and Awakowicz, Peter and Devi, Anjana and Attallah, Ahmed Gamal and Butterling, Maik and Wagner, Andreas and Grundmeier, Guido}}, issn = {{1612-8850}}, journal = {{Plasma Processes and Polymers}}, keywords = {{Polymers and Plastics, Condensed Matter Physics}}, number = {{4}}, publisher = {{Wiley}}, title = {{{Influence of surface activation on the microporosity of PE‐CVD and PE‐ALD SiO x thin films on PDMS}}}, doi = {{10.1002/ppap.202100174}}, volume = {{19}}, year = {{2022}}, } @article{35976, author = {{de los Arcos de Pedro, Maria Teresa and Weinberger, Christian and Zysk, Frederik and Raj Damerla, Varun and Kollmann, Sabrina and Vieth, Pascal and Tiemann, Michael and Kühne, Thomas D. and Grundmeier, Guido}}, issn = {{0169-4332}}, journal = {{Applied Surface Science}}, keywords = {{Surfaces, Coatings and Films, Condensed Matter Physics, Surfaces and Interfaces, General Physics and Astronomy, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Challenges in the interpretation of gas core levels for the determination of gas-solid interactions within dielectric porous films by ambient pressure XPS}}}, doi = {{10.1016/j.apsusc.2022.154525}}, volume = {{604}}, year = {{2022}}, } @article{32174, abstract = {{AbstractIncreasing system complexity can be controlled by using systems engineering processes. INCOSE defines processes with inputs and outputs (artifacts) for this purpose. Specific SE roles are used to organize the tasks of the processes within the company. In this work, the responsibilities for artifacts are evaluated by means of the RACI scheme and examined by a cluster analysis and discussed for a SE transformation project with a German automotive OEM. As a result of the study, the optimal composition for systems engineering teams is identified and the systems engineering roles are prioritized.}}, author = {{Gräßler, Iris and Thiele, Henrik and Grewe, Benedikt and Hieb, Michael}}, issn = {{2732-527X}}, journal = {{Proceedings of the Design Society}}, keywords = {{systems engineering (SE), project management, model-based systems engineering (MBSE)}}, location = {{Dubrovnik}}, pages = {{1875--1884}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{Responsibility Assignment in Systems Engineering}}}, doi = {{10.1017/pds.2022.190}}, volume = {{2}}, year = {{2022}}, } @article{35974, author = {{Xie, Xiaofan and de los Arcos de Pedro, Maria Teresa and Grundmeier, Guido}}, issn = {{1612-8850}}, journal = {{Plasma Processes and Polymers}}, keywords = {{Polymers and Plastics, Condensed Matter Physics}}, number = {{11}}, publisher = {{Wiley}}, title = {{{Comparative analysis of hexamethyldisiloxane and hexamethyldisilazane plasma polymer thin films before and after plasma oxidation}}}, doi = {{10.1002/ppap.202200052}}, volume = {{19}}, year = {{2022}}, } @article{30657, author = {{Henkes, Alexander and Wessels, Henning and Mahnken, Rolf}}, issn = {{0045-7825}}, journal = {{Computer Methods in Applied Mechanics and Engineering}}, keywords = {{Computer Science Applications, General Physics and Astronomy, Mechanical Engineering, Mechanics of Materials, Computational Mechanics}}, publisher = {{Elsevier BV}}, title = {{{Physics informed neural networks for continuum micromechanics}}}, doi = {{10.1016/j.cma.2022.114790}}, volume = {{393}}, year = {{2022}}, }