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Sascha Bernholt Karolina Broman Sara Siebert Ilka Parchmann 《Israel journal of chemistry》2019,59(6-7):554-564
Chemistry requires and combines both observable and mental representations. Still we know that learners often struggle in combining these perspectives successfully, especially when experimental observations contradict the model‐based explanations, e. g. in interpreting the chemical equilibrium as dynamic processes while observing a static system without any visible changes. Digital media offer potentials that might not have been accessible to this degree until now. However, we do not know enough with regard to the degree and effects these media tools have in supporting learning processes but perhaps also in hindering them. This article presents four approaches on how to potentially make use of digital media in learning processes based on theoretical considerations and empirical investigations. The projects will explore applications of media as visualization, learning and investigation tools in chemistry education, embracing techniques from virtual realities to eye‐tracking. 相似文献
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Forschung im Ingenieurwesen - Die Vorteile von elektrischen Hochdrehzahlantrieben mit Mehrganggetriebe gegenüber aktuellen elektrischen Antrieben, konnten durch jüngste... 相似文献
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Sascha Kulas Christian Vogt Andreas Resch Jonas Hartwig Sven Ganske Jonas Matthias Dennis Schlippert Thijs Wendrich Wolfgang Ertmer Ernst Maria Rasel Marcin Damjanic Peter Weßels Anja Kohfeldt Erdenetsetseg Luvsandamdin Max Schiemangk Christoph Grzeschik Markus Krutzik Andreas Wicht Achim Peters Sven Herrmann Claus Lämmerzahl 《Microgravity science and technology》2017,29(1-2):37-48
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Lukas Haneke Felix Pfeiffer Peer Bärmann Jens Wrogemann Christoph Peschel Jonas Neumann Fabian Kux Sascha Nowak Martin Winter Tobias Placke 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(8):2206092
Pre-lithiation via electrolysis, herein defined as electrolytic pre-lithiation, using cost-efficient electrolytes based on lithium chloride (LiCl), is successfully demonstrated as a proof-of-concept for enabling lithium-ion battery full-cells with high silicon content negative electrodes. An electrolyte for pre-lithiation based on γ-butyrolactone and LiCl is optimized using boron-containing additives (lithium bis(oxalato)borate, lithium difluoro(oxalate)borate) and CO2 with respect to the formation of a protective solid electrolyte interphase (SEI) on silicon thin films as model electrodes. Reversible lithiation in Si||Li metal cells is demonstrated with Coulombic efficiencies (CEff) of 95–96% for optimized electrolytes comparable to 1 m LiPF6/EC:EMC 3:7. Formation of an effective SEI is shown by cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). electrolytic pre-lithiation experiments show that notable amounts of the gaseous product Cl2 dissolve in the electrolyte leading to a self-discharge Cl2/Cl− shuttle mechanism between the electrodes lowering pre-lithiation efficiency and causing current collector corrosion. However, no significant degradation of the Si active material and the SEI due to contact with elemental chlorine is found by SEM, impedance, and XPS. In NCM111||Si full-cells, the capacity retention in the 100th cycle can be significantly increased from 54% to 78% by electrolytic pre-lithiation, compared to reference cells without pre-lithiation of Si. 相似文献
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Oana Cojocaru-Mirédin Mohit Raghuwanshi Roland Wuerz Sascha Sadewasser 《Advanced functional materials》2021,31(41):2103119
Cu(In,Ga)Se2 thin-film solar cells have attracted significant research interest in recent decades due to their high efficiency in converting solar energy into electricity for enabling a sustainable future. Although the Cu(In,Ga)Se2 absorber can be grown as a single crystal, its polycrystalline form is dominating the market not only due to its lower costs, but also due to its unexpectedly higher cell efficiency. However, this absorber contains a high fraction of grain boundaries. These are structural defects where deep-trap states can be localized leading to an increase in recombination activity. This controversy is mirrored in the existing literature studies where two main contradictory believes exist: 1) to be crucial grain boundaries in Cu(In,Ga)Se2 absorber are anomalous, being benign in terms of cell performance, and 2) grain boundaries are regions characterized by an increased recombination activity leading to deteriorated cell performance. Therefore, the present review tackles this issue from a novel perspective unraveling correlations between chemical composition of grain boundaries and their corresponding electronic properties. It is shown that features such as Cu depletion/In enrichment, segregation of 1-2at.% of alkali dopants, and passivation by a wide-bandgap or type inversion at grain boundaries are crucial ingredients for low open-circuit voltage loss and, hence, for superior cell performance. 相似文献
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Protein Engineering of the Progesterone Hydroxylating P450‐Monooxygenase CYP17A1 Alters Its Regioselectivity 下载免费PDF全文
Lisa K. Morlock Sascha Grobe Dr. Kathleen Balke Dr. Stephan Mauersberger Dr. Dominique Böttcher Prof. Dr. Uwe T. Bornscheuer 《Chembiochem : a European journal of chemical biology》2018,19(18):1954-1958
The CYP171 enzyme is known to catalyse a key step in the steroidogenesis of mammals. The substrates progesterone and pregnenolone are first hydroxylated at the C17 position, and this is followed by cleavage of the C17?C20 bond to yield important precursors for glucosteroids and androgens. In this study, we focused on the reaction of the bovine CYP17A1 enzyme with progesterone as a substrate. On the basis of a created homology model, active‐site residues were identified and systematically mutated to alanine. In whole‐cell biotransformations, the importance of the N202, R239, G297 and E305 residues for substrate conversion was confirmed. Additionally, mutation of the L206, V366 and V483 residues enhanced the formation of the 16α‐hydroxyprogesterone side product up to 40 % of the total product formation. Furthermore, residue L105 was found not to be involved in this side activity, which contradicts a previous study with the human enzyme. 相似文献