@article{26284, author = {{Bagrets, Dmitry and Kim, Kun Woo and Barkhofen, Sonja and De, Syamsundar and Sperling, Jan and Silberhorn, Christine and Altland, Alexander and Micklitz, Tobias}}, issn = {{2643-1564}}, journal = {{Physical Review Research}}, title = {{{Probing the topological Anderson transition with quantum walks}}}, doi = {{10.1103/physrevresearch.3.023183}}, year = {{2021}}, } @article{21362, author = {{Xue, Yan and Chestnov, Igor and Sedov, Evgeny and Kiktenko, Evgeniy and Fedorov, Aleksey K. and Schumacher, Stefan and Ma, Xuekai and Kavokin, Alexey}}, issn = {{2643-1564}}, journal = {{Physical Review Research}}, number = {{1}}, title = {{{Split-ring polariton condensates as macroscopic two-level quantum systems}}}, doi = {{10.1103/physrevresearch.3.013099}}, volume = {{3}}, year = {{2021}}, } @article{29747, author = {{Jurgen von Bardeleben, Hans and Cantin, Jean-Louis and Gerstmann, Uwe and Schmidt, Wolf Gero and Biktagirov, Timur}}, issn = {{1530-6984}}, journal = {{Nano Letters}}, keywords = {{Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}}, number = {{19}}, pages = {{8119--8125}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Spin Polarization, Electron–Phonon Coupling, and Zero-Phonon Line of the NV Center in 3C-SiC}}}, doi = {{10.1021/acs.nanolett.1c02564}}, volume = {{21}}, year = {{2021}}, } @article{29748, author = {{Slawig, Diana and Gruschwitz, Markus and Gerstmann, Uwe and Rauls, Eva and Tegenkamp, Christoph}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, keywords = {{Surfaces, Coatings and Films, Physical and Theoretical Chemistry, General Energy, Electronic, Optical and Magnetic Materials}}, number = {{36}}, pages = {{20087--20093}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Adsorption and Reaction of PbPc on Hydrogenated Epitaxial Graphene}}}, doi = {{10.1021/acs.jpcc.1c06320}}, volume = {{125}}, year = {{2021}}, } @article{40250, author = {{Jain, Mitisha and Gerstmann, Uwe and Schmidt, Wolf Gero and Aldahhak, Hazem}}, issn = {{0192-8651}}, journal = {{Journal of Computational Chemistry}}, keywords = {{Computational Mathematics, General Chemistry}}, number = {{6}}, pages = {{413--420}}, publisher = {{Wiley}}, title = {{{Adatom mediated adsorption of N‐heterocyclic carbenes on Cu(111) and Au(111)}}}, doi = {{10.1002/jcc.26801}}, volume = {{43}}, year = {{2021}}, } @article{37331, abstract = {{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.}}, author = {{Zuo, Ruixin and Trautmann, Alexander and Wang, Guifang and Hannes, Wolf-Rüdiger and Yang, Shidong and Song, Xiaohong and Meier, Torsten and Ciappina, Marcelo and Duc, Huynh Thanh and Yang, Weifeng}}, issn = {{2765-8791}}, journal = {{Ultrafast Science}}, publisher = {{American Association for the Advancement of Science (AAAS)}}, title = {{{Neighboring Atom Collisions in Solid-State High Harmonic Generation}}}, doi = {{10.34133/2021/9861923}}, volume = {{2021}}, year = {{2021}}, } @article{37338, abstract = {{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.}}, author = {{Berghoff, Daniel and Bühler, Johannes and Bonn, Mischa and Leitenstorfer, Alfred and Meier, Torsten and Kim, Heejae}}, issn = {{2041-1723}}, journal = {{Nature Communications}}, keywords = {{General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Low-field onset of Wannier-Stark localization in a polycrystalline hybrid organic inorganic perovskite}}}, doi = {{10.1038/s41467-021-26021-4}}, volume = {{12}}, year = {{2021}}, } @article{23477, author = {{Thong, Le Huu and Ngo, Cong and Duc, Huynh Thanh and Song, Xiaohong and Meier, Torsten}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{085201}}, title = {{{Microscopic analysis of high harmonic generation in semiconductors with degenerate bands}}}, doi = {{10.1103/physrevb.103.085201}}, volume = {{103}}, year = {{2021}}, } @article{21946, abstract = {{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.}}, author = {{Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}}, issn = {{2073-4352}}, journal = {{Crystals}}, pages = {{542}}, publisher = {{MDPI}}, title = {{{Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}}}, doi = {{10.3390/cryst11050542}}, volume = {{11}}, year = {{2021}}, } @inproceedings{43746, abstract = {{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.}}, author = {{Meier, Torsten and Paul, Jagannath and Rose, Hendrik and Wahlstrand, Jared K and Bristow, Alan D}}, booktitle = {{Frontiers in Optics}}, isbn = {{978-1-55752-308-2}}, location = {{Washington, DC United States}}, publisher = {{Frontiers in Optics}}, title = {{{Coherent and incoherent contribution of population dynamics of semiconductor exciton-polaritons}}}, doi = {{10.1364/FIO.2021.FW5C.6}}, year = {{2021}}, } @inproceedings{23474, author = {{Reichelt, Matthias and Rose, Hendrik and Kosarev, Alexander N. and Poltavtsev, Sergey V. and Bayer, Manfred and Akimov, Ilya A. and Schneider, Christian and Kamp, Martin and Höfling, Sven and Meier, Torsten}}, booktitle = {{Ultrafast Phenomena and Nanophotonics XXV}}, editor = {{Betz, Markus and Elezzabi, Abdulhakem Y.}}, title = {{{Controlling the emission time of photon echoes by optical freezing of exciton dephasing and rephasing in quantum-dot ensembles}}}, doi = {{10.1117/12.2576887}}, volume = {{11684}}, year = {{2021}}, } @article{29749, author = {{Murzakhanov, F. F. and Yavkin, B. V. and Mamin, G. V. and Orlinskii, S. B. and von Bardeleben, H. J. and Biktagirov, Timur and Gerstmann, Uwe and Soltamov, V. A.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{245203}}, publisher = {{American Physical Society (APS)}}, title = {{{Hyperfine and nuclear quadrupole splitting of the NV− ground state in 4H-SiC}}}, doi = {{10.1103/physrevb.103.245203}}, volume = {{103}}, year = {{2021}}, } @article{22010, author = {{Aldahhak, Hazem and Hogan, Conor and Lindner, Susi and Appelfeller, Stephan and Eisele, Holger and Schmidt, Wolf Gero and Dähne, Mario and Gerstmann, Uwe and Franz, Martin}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{035303}}, title = {{{Electronic structure of the Si(111)3×3R30∘−B surface from theory and photoemission spectroscopy}}}, doi = {{10.1103/physrevb.103.035303}}, volume = {{103}}, year = {{2021}}, } @article{23478, author = {{Rose, Hendrik and Popolitova, D. V. and Tikhonova, O. V. and Meier, Torsten and Sharapova, Polina}}, issn = {{2469-9926}}, journal = {{Physical Review A}}, title = {{{Dark-state and loss-induced phenomena in the quantum-optical regime of Λ-type three-level systems}}}, doi = {{10.1103/physreva.103.013702}}, volume = {{103}}, year = {{2021}}, } @article{23473, author = {{Belobo, Didier Belobo and Meier, Torsten}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Approximate nonlinear wave solutions of the coupled two-component Gross–Pitaevskii equations with spin–orbit interaction}}}, doi = {{10.1088/1367-2630/abf3ed}}, volume = {{23}}, year = {{2021}}, } @article{22881, author = {{Nguyen, T. T. Nhung and Sollfrank, T. and Tegenkamp, C. and Rauls, E. and Gerstmann, Uwe}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{L201408}}, title = {{{Impact of screening and relaxation on weakly coupled two-dimensional heterostructures}}}, doi = {{10.1103/physrevb.103.l201408}}, volume = {{103}}, year = {{2021}}, } @article{21635, abstract = {{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.}}, author = {{Borgert, Thomas and Homberg, Werner}}, issn = {{2075-4701}}, journal = {{Metals}}, title = {{{Friction-Induced Recycling Process for User-Specific Semi-Finished Product Production}}}, doi = {{10.3390/met11040663}}, year = {{2021}}, } @inproceedings{23746, author = {{Moritzer, Elmar and Flachmann, Felix}}, booktitle = {{SPE ANTEC 2021: The Annual Technical Conference for Plastic Professionals}}, isbn = {{978-1-7138-3075-7}}, location = {{Online}}, pages = {{536--540}}, title = {{{Influence of Chemical Blowing Agents on the Filling Behavior of Wood-Plastic-Composite Melts}}}, year = {{2021}}, } @article{23789, author = {{Bolenz, Lukas and Ehlert, Thomas and Dechert, Christopher and Bertling, René and Kenig, Eugeny}}, issn = {{0263-8762}}, journal = {{Chemical Engineering Research and Design}}, pages = {{99--108}}, title = {{{Modelling of a continuous distillation process with finite reflux ratio using the hydrodynamic analogy approach}}}, doi = {{10.1016/j.cherd.2021.05.025}}, year = {{2021}}, } @inproceedings{34222, abstract = {{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.}}, author = {{Kappe, Fabian and Bielak, Christian Roman and Sartisson, Vadim and Bobbert, Mathias and Meschut, Gerson}}, booktitle = {{ESAFORM 2021}}, publisher = {{University of Liege}}, title = {{{Influence of rivet length on joint formation on self-piercing riveting process considering further process parameters}}}, doi = {{10.25518/esaform21.4277}}, year = {{2021}}, } @inproceedings{30675, abstract = {{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.}}, author = {{Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}}, booktitle = {{Key Engineering Materials}}, issn = {{1662-9795}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, location = {{online}}, pages = {{127--132}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Numerical and Experimental Fracture Mechanical Investigations of Clinchable Sheet Metals Made of HCT590X}}}, doi = {{10.4028/www.scientific.net/kem.883.127}}, volume = {{883}}, year = {{2021}}, } @article{30674, abstract = {{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.}}, author = {{Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}}, issn = {{0944-6524}}, journal = {{Production Engineering}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Holistic investigation chain for the experimental determination of fracture mechanical material parameters with special specimens}}}, doi = {{10.1007/s11740-021-01096-6}}, year = {{2021}}, } @article{25894, abstract = {{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.}}, author = {{Schwind, Bertram and Smått, Jan-Henrik and Tiemann, Michael and Weinberger, Christian}}, issn = {{1387-1811}}, journal = {{Microporous and Mesoporous Materials}}, title = {{{Modeling of gyroidal mesoporous CMK-8 and CMK-9 carbon nanostructures and their X-Ray diffraction patterns}}}, doi = {{10.1016/j.micromeso.2020.110330}}, year = {{2021}}, } @article{25897, abstract = {{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.}}, author = {{de los Arcos, Teresa and Müller, Hendrik and Wang, Fuzeng and Damerla, Varun Raj and Hoppe, Christian and Weinberger, Christian and Tiemann, Michael and Grundmeier, Guido}}, issn = {{0924-2031}}, journal = {{Vibrational Spectroscopy}}, title = {{{Review of infrared spectroscopy techniques for the determination of internal structure in thin SiO2 films}}}, doi = {{10.1016/j.vibspec.2021.103256}}, year = {{2021}}, } @phdthesis{42812, author = {{Olenberg, Alexander}}, isbn = {{9783843947855}}, title = {{{Untersuchung und Optimierung von strukturierten Packungen mittels CFD-Simulationen }}}, year = {{2021}}, } @article{25893, abstract = {{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.}}, author = {{Tiemann, Michael and Weinberger, Christian}}, issn = {{2196-7350}}, journal = {{Advanced Materials Interfaces}}, title = {{{Selective Modification of Hierarchical Pores and Surfaces in Nanoporous Materials}}}, doi = {{10.1002/admi.202001153}}, year = {{2021}}, } @article{41431, author = {{Fuchs, Christian}}, journal = {{tripleC: Communication, Capitalism & Critique}}, number = {{1}}, pages = {{1--194}}, title = {{{Engels@200: Friedrich Engels in the Age of Digital Capitalism}}}, doi = {{https://doi.org/10.31269/triplec.v19i1.1233}}, volume = {{19}}, year = {{2021}}, } @article{41599, author = {{Fuchs, Christian and Dyer-Witheford, Nick}}, journal = {{国际社会科学杂志 (Journal of International Social Sciences) 2021 (9)}}, pages = {{66--76}}, title = {{{卡尔·马克思与互联网研究}}}, year = {{2021}}, } @article{25896, abstract = {{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.}}, author = {{Tischendorf, R. and Simmler, M. and Weinberger, Christian and Bieber, M. and Reddemann, M. and Fröde, F. and Lindner, J. and Pitsch, H. and Kneer, R. and Tiemann, Michael and Nirschl, H. and Schmid, H.-J.}}, issn = {{0021-8502}}, journal = {{Journal of Aerosol Science}}, title = {{{Examination of the evolution of iron oxide nanoparticles in flame spray pyrolysis by tailored in situ particle sampling techniques}}}, doi = {{10.1016/j.jaerosci.2020.105722}}, year = {{2021}}, } @article{22635, abstract = {{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.}}, author = {{Garcia Diosa, Jaime Andres and Gonzalez Orive, Alejandro and Weinberger, Christian and Schwiderek, Sabrina and Knust, Steffen and Tiemann, Michael and Grundmeier, Guido and Keller, Adrian and Camargo Amado, Ruben Jesus}}, issn = {{1552-4973}}, journal = {{Journal of Biomedical Materials Research Part B: Applied Biomaterials}}, pages = {{2142–2153}}, title = {{{TiO2 nanoparticle coatings on glass surfaces for the selective trapping of leukemia cells from peripheral blood}}}, doi = {{10.1002/jbm.b.34862}}, volume = {{109}}, year = {{2021}}, } @article{25892, abstract = {{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.}}, author = {{Steinke, Felix and Javed, Ali and Wöhlbrandt, Stephan and Tiemann, Michael and Stock, Norbert}}, issn = {{1477-9226}}, journal = {{Dalton Transactions}}, pages = {{13572--13579}}, title = {{{New isoreticular phosphonate MOFs based on a tetratopic linker}}}, doi = {{10.1039/d1dt02610k}}, year = {{2021}}, } @inbook{29061, author = {{Eickelmann, Birgit}}, booktitle = {{Chancen denken. Impulse für eine offene und mutige Gesellschaft im 21. Jahrhundert}}, pages = {{24--35}}, title = {{{Etwas anarchischer, freier, ungewohnter (Ein Gespräch mit Birgit Eickelmann)}}}, year = {{2021}}, } @inbook{29062, author = {{Eickelmann, Birgit and Maaz, Kai}}, booktitle = {{Schule weiter denken}}, editor = {{Maaz, Kai and Becker-Mrotzek, Michael}}, pages = {{132--150}}, publisher = {{Duden-Verlag}}, title = {{{Ungleichheiten im Bildungssystem – eine unangenehme Konstante. Sinnvolle Maßnahmen und die Grenzen des Möglichen}}}, year = {{2021}}, } @misc{29066, author = {{Bonanati, Sabrina and Buhl, Heike M. and Eickelmann, Birgit}}, publisher = {{Hogrefe}}, title = {{{Wie Lernen in digitalen Lernumgebungen motivieren kann – Stichwort: Gamification}}}, year = {{2021}}, } @article{34024, abstract = {{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. }}, author = {{Sherman, David A and Lehmann, Tim and Baumeister, Jochen and Gokeler, Alli and Donovan, Luke and Norte, Grant E}}, issn = {{0031-9023}}, journal = {{Physical Therapy}}, keywords = {{Physical Therapy, Sports Therapy and Rehabilitation}}, publisher = {{Oxford University Press (OUP)}}, title = {{{External Focus of Attention Influences Cortical Activity Associated with Single Limb Balance Performance}}}, doi = {{10.1093/ptj/pzab223}}, year = {{2021}}, } @article{32434, abstract = {{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.}}, author = {{Lehmann, Tim and Büchel, Daniel and Mouton, Caroline and Gokeler, Alli and Seil, Romain and Baumeister, Jochen}}, issn = {{1662-5161}}, journal = {{Frontiers in Human Neuroscience}}, keywords = {{Behavioral Neuroscience, Biological Psychiatry, Psychiatry and Mental health, Neurology, Neuropsychology and Physiological Psychology}}, publisher = {{Frontiers Media SA}}, title = {{{Functional Cortical Connectivity Related to Postural Control in Patients Six Weeks After Anterior Cruciate Ligament Reconstruction}}}, doi = {{10.3389/fnhum.2021.655116}}, volume = {{15}}, year = {{2021}}, } @article{32435, abstract = {{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.}}, author = {{Büchel, Daniel and Lehmann, Tim and Ullrich, Sarah and Cockcroft, John and Louw, Quinette and Baumeister, Jochen}}, issn = {{0014-4819}}, journal = {{Experimental Brain Research}}, keywords = {{General Neuroscience}}, number = {{4}}, pages = {{1193--1202}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Stance leg and surface stability modulate cortical activity during human single leg stance}}}, doi = {{10.1007/s00221-021-06035-6}}, volume = {{239}}, year = {{2021}}, } @article{35626, author = {{Büchel, Daniel and Lehmann, Tim and Sandbakk, Øyvind and Baumeister, Jochen}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, keywords = {{Multidisciplinary}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{EEG‑derived brain graphs are reliable measures for exploring exercise‑induced changes in brain networks}}}, doi = {{10.1038/s41598-021-01494-x}}, volume = {{11}}, year = {{2021}}, } @inproceedings{24475, author = {{Neukötter, Moritz and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, location = {{Online}}, title = {{{Theoretische Beschreibung des Tropfenbildungsprozesses bei der Filament Extension Atomization: Entwicklung eines Vorhersagemodells für die Tropfengröße (Poster)}}}, year = {{2021}}, } @inproceedings{30221, author = {{Neukötter, Moritz and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, location = {{Online}}, title = {{{Filament Extension Atomization – A novel Process for Powder Production? (Presentation)}}}, year = {{2021}}, } @article{43016, author = {{Möhring, Julia and Krumhöfner, Anika and Gräfin von Plettenberg, Elisabeth Gudila Sophia Ida Maria}}, journal = {{-}}, publisher = {{Reinhard Mohn Stiftung, Kreissportbund Gütersloh e.V., Bezirksregierung Detmold}}, title = {{{Bewegungsförderung in Ganztagsschulen}}}, year = {{2021}}, } @techreport{33210, author = {{Leineweber, Jonas}}, title = {{{Veranstaltungsbericht: Immaterielles Kulturerbe in Nordrhein-Westfalen – Steigerlied und Trinkhallenkultur im Ruhrgebiet erhalten Auszeichnung anlässlich der Neuaufnahmen in das nordrhein-westfälische Landesinventar}}}, year = {{2021}}, } @techreport{33209, author = {{Leineweber, Jonas}}, title = {{{Tagungsbericht: Immaterielles Kulturerbe und regionale Identität. Gesellschaftliche Repräsentation und Partizipation im Schützenwesen}}}, year = {{2021}}, } @article{39383, abstract = {{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.}}, author = {{Kaufmann, Ivan Rodrigo and Zerey, Onur and Meyers, Thorsten and Reker, Julia and Vidor, Fábio and Hilleringmann, Ulrich}}, issn = {{2079-4991}}, journal = {{Nanomaterials}}, keywords = {{General Materials Science, General Chemical Engineering}}, number = {{5}}, publisher = {{MDPI AG}}, title = {{{A Study about Schottky Barrier Height and Ideality Factor in Thin Film Transistors with Metal/Zinc Oxide Nanoparticles Structures Aiming Flexible Electronics Application}}}, doi = {{10.3390/nano11051188}}, volume = {{11}}, year = {{2021}}, } @inproceedings{39395, author = {{Reker, Julia and Meyers, Thorsten and Vidor, Fabio F. and Joubert, Trudi-Heleen and Hilleringmann, Ulrich}}, booktitle = {{2021 Smart Systems Integration (SSI)}}, publisher = {{IEEE}}, title = {{{Complementary Inverter Circuits on Flexible Substrates}}}, doi = {{10.1109/ssi52265.2021.9466966}}, year = {{2021}}, } @inproceedings{39381, author = {{Hilleringmann, Ulrich and Petrov, Dmitry and Mwammenywa, Ibrahim and Kagarura, Geoffrey M.}}, booktitle = {{2021 IEEE AFRICON}}, publisher = {{IEEE}}, title = {{{Local Power Control using Wireless Sensor System for Microgrids in Africa}}}, doi = {{10.1109/africon51333.2021.9570970}}, year = {{2021}}, } @inproceedings{39385, author = {{Andrews, George and Hilleringmann, Ulrich and Joubert, Trudi-Heleen}}, booktitle = {{2021 IEEE AFRICON}}, publisher = {{IEEE}}, title = {{{The Viability of a Non-Flow Capacitive Biosensing Microsystem for Whole Cell Counting}}}, doi = {{10.1109/africon51333.2021.9570870}}, year = {{2021}}, } @inproceedings{39386, author = {{Andrews, George and Hilleringmann, Ulrich and Joubert, Trudi-Heleen}}, booktitle = {{2021 IEEE AFRICON}}, publisher = {{IEEE}}, title = {{{The Viability of a Non-Flow Capacitive Biosensing Microsystem for Whole Cell Counting}}}, doi = {{10.1109/africon51333.2021.9570870}}, year = {{2021}}, } @inbook{43143, author = {{Gerhardts, Lara and Dehmel, Lukas and Meister, Dorothee M.}}, booktitle = {{Jahrbuch Medienpädagogik 16. Medienpädagogik in Zeiten einer tiefgreifenden Mediatisierung}}, editor = {{Wolf, Karsten D and Rummler, Klaus and Bettinger, Patrick and Aßmann, Sandra}}, pages = {{129--159}}, title = {{{Die berufliche Tabletaneignung von Lehrkräften als Beispiel der Mediatisierung pädagogischer Handlungskontexte. Theoretische Perspektiven und empirische Befunde}}}, doi = {{https://doi.org/10.21240/mpaed/jb16/2021.01.15.X}}, year = {{2021}}, } @inbook{43142, author = {{Dehmel, Lukas}}, booktitle = {{Erwachsenenpädagogische Digitalisierungsforschung. Impulse - Befunde - Perspektiven. Bielefeld}}, editor = {{ Bernhard-Skala,, Christian and Bolten-Bühler, Ricarda and Koller, Julia and Rohs, Matthias and Wahl, Johannes }}, pages = {{205--219}}, publisher = {{wbv}}, title = {{{Zur Entgrenzung der Arbeit des medienpädagogischen Weiterbildungspersonals im Kontext tiefgreifender Mediatisierung}}}, year = {{2021}}, }