TY - GEN A1 - Kashkarov, Egor B. A1 - Obrosov, Aleksei A1 - Sutygina, Alina N. A1 - Uludintceva, Elena A1 - Mitrofanov, Andrei A1 - Weiß, Sabine T1 - Hydrogen permeation, and mechanical and tribological behavior, of CrNx coatings deposited at various bias voltages on IN718 by direct current reactive sputtering T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - In the current work, the microstructure, hydrogen permeability, and properties of chromium nitride (CrNx) thin films deposited on the Inconel 718 superalloy using direct current reactive sputtering are investigated. The influence of the substrate bias voltage on the crystal structure, mechanical, and tribological properties before and after hydrogen exposure was studied. It was found that increasing the substrate bias voltage leads to densification of the coating. X-ray diffraction (XRD) results reveal a change from mixed fcc-CrN + hcp-Cr2N to the approximately stoichiometric hcp-Cr2N phase with increasing substrate bias confirmed by wavelength-dispersive X-ray spectroscopy (WDS). The texture coefficients of (113), (110), and (111) planes vary significantly with increasing substrate bias voltage. The hydrogen permeability was measured by gas-phase hydrogenation. The CrN coating deposited at 60 V with mixed c-CrN and (113) textured hcp-Cr2N phases exhibits the lowest hydrogen absorption at 873 K. It is suggested that the crystal orientation is only one parameter influencing the permeation resistance of the CrNx coating together with the film structure, the presence of mixing phases, and the packing density of the structure. After hydrogenation, the hardness increased for all coatings, which could be related to the formation of a Cr2O3 oxide film on the surface, as well as the defect formation after hydrogen loading. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient by up to 40%. The lowest value of 0.25 +/- 0.02 was reached for the CrNx coating deposited at 60 V after hydrogenation. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1017 KW - CrNx coatings KW - Physical Vapour Deposition (PVD) KW - hydrogenation KW - Tribology KW - mechanical properties KW - X-ray diffraction Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459846 SN - 1866-8372 IS - 1017 ER - TY - JOUR A1 - Zühlke, Martin A1 - Meiling, Till Thomas A1 - Roder, Phillip A1 - Riebe, Daniel A1 - Beitz, Toralf A1 - Bald, Ilko A1 - Löhmannsröben, Hans-Gerd A1 - Janßen, Traute A1 - Erhard, Marcel A1 - Repp, Alexander T1 - Photodynamic inactivation of E. coli bacteria via carbon nanodots JF - ACS omega / American Chemical Society N2 - The increasing development of antibiotic resistance in bacteria has been a major problem for years, both in human and veterinary medicine. Prophylactic measures, such as the use of vaccines, are of great importance in reducing the use of antibiotics in livestock. These vaccines are mainly produced based on formaldehyde inactivation. However, the latter damages the recognition elements of the bacterial proteins and thus could reduce the immune response in the animal. An alternative inactivation method developed in this work is based on gentle photodynamic inactivation using carbon nanodots (CNDs) at excitation wavelengths λex > 290 nm. The photodynamic inactivation was characterized on the nonvirulent laboratory strain Escherichia coli K12 using synthesized CNDs. For a gentle inactivation, the CNDs must be absorbed into the cytoplasm of the E. coli cell. Thus, the inactivation through photoinduced formation of reactive oxygen species only takes place inside the bacterium, which means that the outer membrane is neither damaged nor altered. The loading of the CNDs into E. coli was examined using fluorescence microscopy. Complete loading of the bacterial cells could be achieved in less than 10 min. These studies revealed a reversible uptake process allowing the recovery and reuse of the CNDs after irradiation and before the administration of the vaccine. The success of photodynamic inactivation was verified by viability assays on agar. In a homemade flow photoreactor, the fastest successful irradiation of the bacteria could be carried out in 34 s. Therefore, the photodynamic inactivation based on CNDs is very effective. The membrane integrity of the bacteria after irradiation was verified by slide agglutination and atomic force microscopy. The method developed for the laboratory strain E. coli K12 could then be successfully applied to the important avian pathogens Bordetella avium and Ornithobacterium rhinotracheale to aid the development of novel vaccines. KW - Bacteria KW - Genetics KW - Fluorescence KW - Photodynamics KW - Irradiation Y1 - 2021 U6 - https://doi.org/10.1021/acsomega.1c01700 SN - 2470-1343 VL - 6 IS - 37 SP - 23742 EP - 23749 PB - ACS Publications CY - Washington, DC ER - TY - JOUR A1 - Robinson, Matthew Scott A1 - Niebuhr, Mario A1 - Lever, Fabiano A1 - Mayer, Dennis A1 - Metje, Jan A1 - Gühr, Markus T1 - Ultrafast photo-ion probing of the ring-opening process in trans-stilbene oxide JF - Chemistry - a European journal N2 - The ultrafast photo-induced ring opening of the oxirane derivative trans-stilbene oxide has been studied through the use of ultrafast UV/UV pump-probe spectroscopy by using photo-ion detection. Single- and multiphoton probe paths and final states were identified through comparisons between UV power studies and synchrotron-based vacuum ultraviolet (VUV) single-photon ionization studies. Three major time-dependent features of the parent ion (sub-450 fs decay, (1.5 +/- 0.2) ps, and >100 ps) were observed. These decays are discussed in conjunction with the primary ring-opening mechanism of stilbene oxide, which occurs through C-C dissociation in the oxirane ring. The appearance of fragments relating to the masses of dehydrogenated diphenylmethane (167 amu) and dehydrogenated methylbenzene (90 amu) were also investigated. The appearance of the 167 amu fragment could suggest an alternative ultrafast ring-opening pathway via the dissociation of one of the C-O bonds within the oxirane ring. KW - femtochemistry KW - mass spectrometry KW - photochemistry KW - small ring systems KW - stilbene oxide Y1 - 2021 U6 - https://doi.org/10.1002/chem.202101343 SN - 1521-3765 VL - 27 IS - 44 SP - 11418 EP - 11427 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Schladebach, Marcus A1 - Bârsan, Catinca T1 - Der Mondbergbau als völkerrechtliche Herausforderung JF - Zeitschrift für Bergrecht Y1 - 2023 SN - 0340-3939 VL - 164 IS - 2 SP - 97 EP - 107 PB - Carl Heymanns Verlag CY - Köln ER - TY - JOUR A1 - Hackethal, Christin A1 - Kopp, Johannes Florian A1 - Sarvan, Irmela A1 - Schwerdtle, Tanja A1 - Lindtner, Oliver T1 - Total arsenic and water-soluble arsenic species in foods of the first German total diet study (BfR MEAL Study) JF - Food chemistry N2 - Arsenic can occur in foods as inorganic and organic forms. Inorganic arsenic is more toxic than most watersoluble organic arsenic compounds such as arsenobetaine, which is presumed to be harmless for humans. Within the first German total diet study, total arsenic, inorganic arsenic, arsenobetaine, dimethylarsinic acid and monomethylarsonic acid were analyzed in various foods. Highest levels of total arsenic were found in fish, fish products and seafood (mean: 1.43 mg kg(-1); n = 39; min-max: 0.01-6.15 mg kg(-1)), with arsenobetaine confirmed as the predominant arsenic species (1.233 mg kg 1; n = 39; min-max: 0.01-6.23 mg kg (1)). In contrast, inorganic arsenic was determined as prevalent arsenic species in terrestrial foods (0.02 mg kg (1); n = 38; min-max: 0-0.11 mg kg (1)). However, the toxicity of arsenic species varies and measurements are necessary to gain information about the composition and changes of arsenic species in foods due to household processing of foods. KW - Occurrence data KW - Food KW - Total arsenic KW - Arsenic speciation KW - Inductively KW - coupled plasma mass spectrometry Y1 - 2021 U6 - https://doi.org/10.1016/j.foodchem.2020.128913 SN - 0308-8146 SN - 1873-7072 VL - 346 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Keckeis, Philipp A1 - Zeller, Enriko A1 - Jung, Carina A1 - Besirske, Patricia A1 - Kirner, Felizitas A1 - Ruiz-Agudo, Cristina A1 - Schlaad, Helmut A1 - Cölfen, Helmut T1 - Modular toolkit of multifunctional block copoly(2-oxazoline)s for the synthesis of nanoparticles JF - Chemistry - a European journal N2 - Post-polymerization modification provides an elegant way to introduce chemical functionalities onto macromolecules to produce tailor-made materials with superior properties. This concept was adapted to well-defined block copolymers of the poly(2-oxazoline) family and demonstrated the large potential of these macromolecules as universal toolkit for numerous applications. Triblock copolymers with separated water-soluble, alkyne- and alkene-containing segments were synthesized and orthogonally modified with various low-molecular weight functional molecules by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) and thiol-ene (TE) click reactions, respectively. Representative toolkit polymers were used for the synthesis of gold, iron oxide and silica nanoparticles. KW - block copolymers KW - click chemistry KW - nanoparticles KW - ring-opening KW - polymerization KW - surfactants Y1 - 2021 U6 - https://doi.org/10.1002/chem.202101327 SN - 0947-6539 SN - 1521-3765 VL - 27 IS - 32 SP - 8283 EP - 8287 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Niedl, Robert Raimund A1 - Beta, Carsten T1 - Hydrogel-driven paper-based microfluidics N2 - Paper-based microfluidics provide an inexpensive, easy to use technology for point-of-care diagnostics in developing countries. Here, we combine paper-based microfluidic devices with responsive hydrogels to add an entire new class of functions to these versatile low-cost fluidic systems. The hydrogels serve as fluid reservoirs. In response to an external stimulus, e.g. an increase in temperature, the hydrogels collapse and release fluid into the structured paper substrate. In this way, chemicals that are either stored on the paper substrate or inside the hydrogel pads can be dissolved, premixed, and brought to reaction to fulfill specific analytic tasks. We demonstrate that multi-step sequences of chemical reactions can be implemented in a paper-based system and operated without the need for external precision pumps. We exemplify this technology by integrating an antibody-based E. coli test on a small and easy to use paper device. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 193 Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-81083 SP - 2452 EP - 2459 ER - TY - JOUR A1 - Laquai, René A1 - Schaupp, Thomas A1 - Griesche, Axel A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Hannemann, Andreas A1 - Kannengiesser, Thomas A1 - Bruno, Giovanni T1 - Quantitative analysis of hydrogen-assisted microcracking in duplex stainless steel through X-ray refraction 3D imaging JF - Advanced engineering materials N2 - While the problem of the identification of mechanisms of hydrogen-assisted damage has and is being thoroughly studied, the quantitative analysis of such damage still lacks suitable tools. In fact, while, for instance, electron microscopy yields excellent characterization, the quantitative analysis of damage requires at the same time large field-of-views and high spatial resolution. Synchrotron X-ray refraction techniques do possess both features. Herein, it is shown how synchrotron X-ray refraction computed tomography (SXRCT) can quantify damage induced by hydrogen embrittlement in a lean duplex steel, yielding results that overperform even those achievable by synchrotron X-ray absorption computed tomography. As already reported in the literature, but this time using a nondestructive technique, it is shown that the hydrogen charge does not penetrate to the center of tensile specimens. By the comparison between virgin and hydrogen-charged specimens, it is deduced that cracks in the specimen bulk are due to the rolling process rather than hydrogen-assisted. It is shown that (micro)cracks propagate from the surface of tensile specimens to the interior with increasing applied strain, and it is deduced that a significant crack propagation can only be observed short before rupture. KW - 2101 duplex stainless steel KW - computed tomography KW - fractography KW - hydrogen KW - embrittlement KW - microcracking KW - synchrotron radiation KW - X-ray refraction Y1 - 2022 U6 - https://doi.org/10.1002/adem.202101287 SN - 1527-2648 VL - 24 IS - 6 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Balischewski, Christian A1 - Behrens, Karsten A1 - Zehbe, Kerstin A1 - Günter, Christina A1 - Mies, Stefan A1 - Sperlich, Eric A1 - Kelling, Alexandra A1 - Taubert, Andreas T1 - Ionic liquids with more than one metal BT - optical and rlectrochemical properties versus d-block metal vombinations JF - Chemistry - a European journal N2 - Thirteen N-butylpyridinium salts, including three monometallic [C4Py](2)[MCl4], nine bimetallic [C4Py](2)[(M1-xMxCl4)-M-a-Cl-b] and one trimetallic compound [C4Py](2)[(M1-y-zMyMz (c) Cl4)-M-a-M-b] (M=Co, Cu, Mn; x=0.25, 0.50 or 0.75 and y=z=0.33), were synthesized and their structure and thermal and electrochemical properties were studied. All compounds are ionic liquids (ILs) with melting points between 69 and 93 degrees C. X-ray diffraction proves that all ILs are isostructural. The conductivity at room temperature is between 10(-4) and 10(-8) S cm(-1). Some Cu-based ILs reach conductivities of 10(-2) S cm(-1), which is, however, probably due to IL dec. This correlates with the optical bandgap measurements indicating the formation of large bandgap semiconductors. At elevated temperatures approaching the melting points, the conductivities reach up to 1.47x10(-1) S cm(-1) at 70 degrees C. The electrochemical stability windows of the ILs are between 2.5 and 3.0 V. KW - bandgap KW - electrochemistry KW - ionic liquids KW - metal-containing ionic KW - liquids KW - tetrahalido metallates Y1 - 2020 U6 - https://doi.org/10.1002/chem.202003097 SN - 0947-6539 SN - 1521-3765 VL - 26 IS - 72 SP - 17504 EP - 17513 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Sprengel, Maximilian A1 - Mohr, Gunther A1 - Altenburg, Simon J. A1 - Evans, Alexander A1 - Serrano-Munoz, Itziar A1 - Kromm, Arne A1 - Pirling, Thilo A1 - Bruno, Giovanni A1 - Kannengießer, Thomas T1 - Triaxial residual stress in Laser Powder Bed Fused 316L BT - effects of interlayer time and scanning velocity JF - Advanced engineering materials N2 - The control of residual stress (RS) remains a challenge in the manufacturing of metallic parts using the laser powder bed fusion process (LPBF). This layer-by-layer manufacturing approach gives rise to complex triaxial RS distributions, which require extensive characterization effort for a broader acceptance of LPBF in industry. This study focuses on the distribution of bulk triaxial RS and surface RS in LPBF austenitic steel 316L. The RS are determined by X-ray and neutron diffraction to characterize the RS distribution. Variations in the LPBF parameters interlayer time (ILT) and scanning velocity and their influence on the temperature distribution and resulting RS is investigated using thermographic data from in situ process monitoring. The RS in the LPBF 316L is tensile at the surface and compressive in the bulk. The RS is directly related to the thermal history of the part as shown by the in situ thermography data. Shorter ILT leads to higher temperatures of the part during the manufacturing, which decrease the RS and RS formation mechanisms. Interestingly, the surface RS does not agree with this observation. This study highlights the benefit of using multiple RS determination methods and in situ thermography monitoring to characterize the RS in LPBF processed parts. KW - in situ thermography KW - interlayer time KW - laser powder bed fusions KW - triaxial residual stresses KW - X-ray and neutron diffractions Y1 - 2021 U6 - https://doi.org/10.1002/adem.202101330 SN - 1438-1656 SN - 1527-2648 VL - 24 IS - 6 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Sorgenfrei, Nomi A1 - Giangrisostomi, Erika A1 - Jay, Raphael Martin A1 - Kühn, Danilo A1 - Neppl, Stefan A1 - Ovsyannikov, Ruslan A1 - Sezen, Hikmet A1 - Svensson, Svante A1 - Föhlisch, Alexander T1 - Photodriven transient picosecond top-layer semiconductor to metal phase-transition in p-doped molybdenum disulfide JF - Advanced materials N2 - Visible light is shown to create a transient metallic S-Mo-S surface layer on bulk semiconducting p-doped indirect-bandgap 2H-MoS2. Optically created electron-hole pairs separate in the surface band bending region of the p-doped semiconducting crystal causing a transient accumulation of electrons in the surface region. This triggers a reversible 2H-semiconductor to 1T-metal phase-transition of the surface layer. Electron-phonon coupling of the indirect-bandgap p-doped 2H-MoS2 enables this efficient pathway even at a low density of excited electrons with a distinct optical excitation threshold and saturation behavior. This mechanism needs to be taken into consideration when describing the surface properties of illuminated p-doped 2H-MoS2. In particular, light-induced increased charge mobility and surface activation can cause and enhance the photocatalytic and photoassisted electrochemical hydrogen evolution reaction of water on 2H-MoS2. Generally, it opens up for a way to control not only the surface of p-doped 2H-MoS2 but also related dichalcogenides and layered systems. The findings are based on the sensitivity of time-resolved electron spectroscopy for chemical analysis with photon-energy-tuneable synchrotron radiation. KW - catalysis KW - dichalcogenides KW - hydrogen evolution reaction KW - phase transitions KW - photoelectron spectroscopy Y1 - 2021 U6 - https://doi.org/10.1002/adma.202006957 SN - 0935-9648 SN - 1521-4095 VL - 33 IS - 14 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Eckert, Sebastian A1 - Norell, Jesper A1 - Miedema, Piter S. A1 - Beye, Martin A1 - Fondell, Mattis A1 - Quevedo, Wilson A1 - Kennedy, Brian A1 - Hantschmann, Markus A1 - Pietzsch, Annette A1 - van Kuiken, Benjamin E. A1 - Ross, Matthew A1 - Minitti, Michael P. A1 - Moeller, Stefan P. A1 - Schlotter, William F. A1 - Khalil, Munira A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - Untersuchung unabhängiger N‐H‐ und N‐C‐Bindungsverformungen auf ultrakurzen Zeitskalen mit resonanter inelastischer Röntgenstreuung T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Die Femtosekundendynamik nach resonanten Photoanregungen mit optischen und Röntgenpulsen ermöglicht eine selektive Verformung von chemischen N‐H‐ und N‐C‐Bindungen in 2‐Thiopyridon in wässriger Lösung. Die Untersuchung der orbitalspezifischen elektronischen Struktur und ihrer Dynamik auf ultrakurzen Zeitskalen mit resonanter inelastischer Röntgenstreuung an der N1s‐Resonanz am Synchrotron und dem Freie‐Elektronen‐Laser LCLS in Kombination mit quantenchemischen Multikonfigurationsberechnungen erbringen den direkten Nachweis dieser kontrollierten photoinduzierten Molekülverformungen und ihrer ultrakurzen Zeitskala. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1121 KW - Photochemie KW - Protonierung KW - RIXS (resonante inelastische Röntgenstreuung) KW - Selektiver Bindungsbruch KW - Stickstoff Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436688 SN - 1866-8372 IS - 1121 ER - TY - GEN A1 - Eckert, Sebastian A1 - Norell, Jesper A1 - Miedema, Piter S. A1 - Beye, Martin A1 - Fondell, Mattis A1 - Quevedo, Wilson A1 - Kennedy, Brian A1 - Hantschmann, Markus A1 - Pietzsch, Annette A1 - van Kuiken, Benjamin E. A1 - Ross, Matthew A1 - Minitti, Michael P. A1 - Moeller, Stefan P. A1 - Schlotter, William F. A1 - Khalil, Munira A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - Ultrafast Independent N-H and N-C Bond Deformation Investigated with Resonant Inelastic X-Ray Scattering T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The femtosecond excited-state dynamics following resonant photoexcitation enable the selective deformation of N-H and N-C chemical bonds in 2-thiopyridone in aqueous solution with optical or X-ray pulses. In combination with multiconfigurational quantum-chemical calculations, the orbital-specific electronic structure and its ultrafast dynamics accessed with resonant inelastic X-ray scattering at the N 1s level using synchrotron radiation and the soft X-ray free-electron laser LCLS provide direct evidence for this controlled photoinduced molecular deformation and its ultrashort time-scale. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1115 KW - nitrogen KW - photochemistry KW - protonation KW - RIXS (resonant inelastic X-ray scattering) KW - selective bond cleavage Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436873 SN - 1866-8372 IS - 1115 ER - TY - JOUR A1 - Gilmanova, Alina A1 - Wang, Zhifeng A1 - Gosens, Jorrit A1 - Lilliestam, Johan T1 - Building an internationally competitive concentrating solar power industry in China BT - lessons from wind power and photovoltaics JF - Energy sources : B, economics, planning and policy N2 - This article draws lessons from experiences of developing the photovoltaic (PV) and onshore wind power sectors in China for the development of Chinese Concentrated Solar Power (CSP) into an internationally competitive industry. We analyze the sectoral development with a framework that expands on the concept of lead markets, identifying factors that determine whether domestic industrial development paths may or may not generate export success. We find that the Chinese CSP sector has good potential for becoming internationally competitive because of a strong Chinese knowledge base, a clear eye for product quality, standard-setting, and a focus on the high-efficiency and large-storage technological routes most likely to see growing demand in future international markets. Chinese solar towers are already cheaper than international competitors and so far, appear reliable. However, continued and stable deployment support for CSP, designed to reward dispatchable solar power generation, enabling continued domestic learning-by-doing and -interacting is likely required to realize this export potential. To date, Chinese CSP policy has done many things right and, if the domestic market is maintained through renewed support, has put the Chinese industry well on the path to international competitiveness. KW - lead markets KW - China KW - concentrated solar power KW - renewable energy industry KW - international competitiveness Y1 - 2021 U6 - https://doi.org/10.1080/15567249.2021.1931563 SN - 1556-7249 SN - 1556-7257 VL - 16 IS - 6 SP - 515 EP - 541 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Silva, Bibiana A1 - Oliveira Costa, Ana Carolina A1 - Tchewonpi, Sorel Sagu A1 - Bönick, Josephine A1 - Huschek, Gerd A1 - Gonzaga, Luciano Valdemiro A1 - Fett, Roseane A1 - Baldermann, Susanne A1 - Rawel, Harshadrai Manilal T1 - Comparative quantification and differentiation of bracatinga (Mimosa scabrella Bentham) honeydew honey proteins using targeted peptide markers identified by high-resolution mass spectrometry JF - Food research international N2 - Honey traceability is an important topic, especially for honeydew honeys, due to the increased incidence of adulteration. This study aimed to establish specific markers to quantify proteins in honey. A proteomics strategy to identify marker peptides from bracatinga honeydew honey was therefore developed. The proteomics approach was based on initial untargeted identification of honey proteins and peptides by LC-ESI-Triple-TOF-MS/MS, which identified the major royal jelly proteins (MRJP) presence. Afterwards, the peptides were selected by the in silico digestion. The marker peptides were quantified by the developed targeted LC-QqQ-MS/MS method, which provided good linearity and specificity, besides recoveries between 92 and 100% to quantify peptides from bracatinga honeydew honey. The uniqueness and high response in mass spectrometry were backed by further complementary protein analysis (SDS-PAGE). The selected marker peptides EALPHVPIFDR (MRJP 1), ILGANVK (MRJP 2), TFVTIER (MRJP 3), QNIDVVAR (MRJP 4), FINNDYNFNEVNFR (MRJP 5) and LLQPYPDWSWTK (MRJP 7), quantified by LC-QqQ-MS/MS, highlighted that the content of QNIDVVAR from MRJP 4 could be used to differentiate bracatinga honeydew honey from floral honeys (p < 0.05) as a potential marker for its authentication. Finally, principal components analysis highlighted the QNIDVVAR content as a good descriptor of the analyzed bracatinga honeydew honey samples. KW - Honeydew honey KW - Major royal jelly proteins KW - Marker peptides KW - High-resolution mass spectrometry KW - Principal component analysis Y1 - 2020 U6 - https://doi.org/10.1016/j.foodres.2020.109991 SN - 0963-9969 SN - 1873-7145 VL - 141 PB - Elsevier CY - New York, NY [u.a.] ER - TY - JOUR A1 - Weger Coenen, Lindsey A1 - Leitão, Joana A1 - Lawrence, Mark T1 - Expected impacts on greenhouse gas and air pollutant emissions due to a possible transition towards a hydrogen economy in German road transport JF - International journal of hydrogen energy : official journal of the International Association for Hydrogen Energy N2 - Transitioning German road transport partially to hydrogen energy is among the possibilities being discussed to help meet national climate targets. This study investigates impacts of a hypothetical, complete transition from conventionally-fueled to hydrogen-powered German transport through representative scenarios. Our results show that German emissions change between -179 and +95 MtCO(2)eq annually, depending on the scenario, with renewable-powered electrolysis leading to the greatest emissions reduction, while electrolysis using the fossilintense current electricity mix leads to the greatest increase. German energy emissions of regulated pollutants decrease significantly, indicating the potential for simultaneous air quality improvements. Vehicular hydrogen demand is 1000 PJ annually, requiring 446-525 TWh for electrolysis, hydrogen transport and storage, which could be supplied by future German renewable generation, supporting the potential for CO2-free hydrogen traffic and increased energy security. Thus hydrogen-powered transport could contribute significantly to climate and air quality goals, warranting further research and political discussion about this possibility. KW - Hydrogen economy KW - German road transport KW - Greenhouse gas mitigation KW - Air KW - pollution KW - Fuel cell electric vehicle KW - Emission scenarios Y1 - 2021 U6 - https://doi.org/10.1016/j.ijhydene.2020.11.014 SN - 0360-3199 SN - 1879-3487 VL - 46 IS - 7 SP - 5875 EP - 5890 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Geiger, Christina A1 - Reitenbach, Julija A1 - Henschel, Cristiane A1 - Kreuzer, Lucas A1 - Widmann, Tobias A1 - Wang, Peixi A1 - Mangiapia, Gaetano A1 - Moulin, Jean-François A1 - Papadakis, Christine M. A1 - Laschewsky, André A1 - Müller-Buschbaum, Peter T1 - Ternary nanoswitches realized with multiresponsive PMMA-b-PNIPMAM films in mixed water/acetone vapor atmospheres JF - Advanced engineering materials N2 - To systematically add functionality to nanoscale polymer switches, an understanding of their responsive behavior is crucial. Herein, solvent vapor stimuli are applied to thin films of a diblock copolymer consisting of a short poly(methyl methacrylate) (PMMA) block and a long poly(N-isopropylmethacrylamide) (PNIPMAM) block for realizing ternary nanoswitches. Three significantly distinct film states are successfully implemented by the combination of amphiphilicity and co-nonsolvency effect. The exposure of the thin films to nitrogen, pure water vapor, and mixed water/acetone (90 vol%/10 vol%) vapor switches the films from a dried to a hydrated (solvated and swollen) and a water/acetone-exchanged (solvated and contracted) equilibrium state. These three states have distinctly different film thicknesses and solvent contents, which act as switch positions "off," "on," and "standby." For understanding the switching process, time-of-flight neutron reflectometry (ToF-NR) and spectral reflectance (SR) studies of the swelling and dehydration process are complemented by information on the local solvation of functional groups probed with Fourier-transform infrared (FTIR) spectroscopy. An accelerated responsive behavior beyond a minimum hydration/solvation level is attributed to the fast build-up and depletion of the hydration shell of PNIPMAM, caused by its hydrophobic moieties promoting a cooperative hydration character. KW - co-nonsolvency KW - diblock copolymers KW - nanoswitches KW - neutron reflectometry KW - thin films Y1 - 2021 U6 - https://doi.org/10.1002/adem.202100191 SN - 1438-1656 SN - 1527-2648 VL - 23 IS - 11 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Glatzel, Julia A1 - Noack, Sebastian A1 - Schanzenbach, Dirk A1 - Schlaad, Helmut T1 - Anionic polymerization of dienes in ‘green’ solvents JF - Polymer international N2 - Isoprene and beta-myrcene were polymerized by anionic polymerization in bulk and in the 'green' ether solvents cyclopentyl methyl ether and 2-methyltetrahydrofuran and, for comparison, in cyclohexane and tetrahydrofuran. The polydienes produced in bulk and in cyclohexane contained high amounts of 1,4 units (>90%) whereas those produced in ether solvents were rich in 1,2 and 3,4 units (36%-86%). Comparison of the microstructures and glass transition temperatures of the polydienes obtained in the various solvents suggests that conventionally used solvents can be substituted by environmentally more friendly alternatives. KW - isoprene KW - β‐myrcene KW - anionic polymerization KW - green KW - solvents KW - microstructure KW - glass transition Y1 - 2020 U6 - https://doi.org/10.1002/pi.6152 SN - 0959-8103 SN - 1097-0126 VL - 70 IS - 2 SP - 181 EP - 184 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Mazarei, Elham A1 - Penschke, Christopher A1 - Saalfrank, Peter T1 - Band gap engineering in two-dimensional materials by functionalization BT - Methylation of graphene and graphene bilayers JF - ACS Omega N2 - Graphene is well-knownfor its unique combination of electricaland mechanical properties. However, its vanishing band gap limitsthe use of graphene in microelectronics. Covalent functionalizationof graphene has been a common approach to address this critical issueand introduce a band gap. In this Article, we systematically analyzethe functionalization of single-layer graphene (SLG) and bilayer graphene(BLG) with methyl (CH3) using periodic density functionaltheory (DFT) at the PBE+D3 level of theory. We also include a comparisonof methylated single-layer and bilayer graphene, as well as a discussionof different methylation options (radicalic, cationic, and anionic).For SLG, methyl coverages ranging from 1/8 to 1/1, (i.e.,the fully methylated analogue of graphane) are considered. We findthat up to a coverage theta of 1/2, graphene readily accepts CH3, with neighbor CH3 groups preferring trans positions. Above theta = 1/2, the tendency to accept further CH3 weakens and the lattice constant increases. The band gapbehaves less regularly, but overall it increases with increasing methylcoverage. Thus, methylated graphene shows potential for developingband gap-tuned microelectronics devices and may offer further functionalizationoptions. To guide in the interpretation of methylation experiments,vibrational signatures of various species are characterized by normal-modeanalysis (NMA), their vibrational density of states (VDOS), and infrared(IR) spectra, the latter two are obtained from ab initio moleculardynamics (AIMD) in combination with a velocity-velocity autocorrelationfunction (VVAF) approach. KW - Adsorption KW - Alkyls KW - Band structure KW - Electrical conductivity KW - Two dimensional materials Y1 - 2023 U6 - https://doi.org/10.1021/acsomega.3c02068 SN - 2470-1343 VL - 8 IS - 24 SP - 22026 EP - 22041 PB - American Chemical Society CY - Washington ER - TY - GEN A1 - Wolff, Christian Michael A1 - Caprioglio, Pietro A1 - Stolterfoht, Martin A1 - Neher, Dieter T1 - Nonradiative recombination in perovskite solar cells BT - the role of interfaces T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Perovskite solar cells combine high carrier mobilities with long carrier lifetimes and high radiative efficiencies. Despite this, full devices suffer from significant nonradiative recombination losses, limiting their VOC to values well below the Shockley–Queisser limit. Here, recent advances in understanding nonradiative recombination in perovskite solar cells from picoseconds to steady state are presented, with an emphasis on the interfaces between the perovskite absorber and the charge transport layers. Quantification of the quasi‐Fermi level splitting in perovskite films with and without attached transport layers allows to identify the origin of nonradiative recombination, and to explain the VOC of operational devices. These measurements prove that in state‐of‐the‐art solar cells, nonradiative recombination at the interfaces between the perovskite and the transport layers is more important than processes in the bulk or at grain boundaries. Optical pump‐probe techniques give complementary access to the interfacial recombination pathways and provide quantitative information on transfer rates and recombination velocities. Promising optimization strategies are also highlighted, in particular in view of the role of energy level alignment and the importance of surface passivation. Recent record perovskite solar cells with low nonradiative losses are presented where interfacial recombination is effectively overcome—paving the way to the thermodynamic efficiency limit. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 772 KW - interfacial recombination KW - open‐circuit voltage KW - perovskite solar cells KW - photoluminescence Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-437626 SN - 1866-8372 IS - 772 ER - TY - JOUR A1 - Arboleda-Zapata, Mauricio A1 - Guillemoteau, Julien A1 - Tronicke, Jens T1 - A comprehensive workflow to analyze ensembles of globally inverted 2D electrical resistivity models JF - Journal of applied geophysics N2 - Electrical resistivity tomography (ERT) aims at imaging the subsurface resistivity distribution and provides valuable information for different geological, engineering, and hydrological applications. To obtain a subsurface resistivity model from measured apparent resistivities, stochastic or deterministic inversion procedures may be employed. Typically, the inversion of ERT data results in non-unique solutions; i.e., an ensemble of different models explains the measured data equally well. In this study, we perform inference analysis of model ensembles generated using a well-established global inversion approach to assess uncertainties related to the nonuniqueness of the inverse problem. Our interpretation strategy starts by establishing model selection criteria based on different statistical descriptors calculated from the data residuals. Then, we perform cluster analysis considering the inverted resistivity models and the corresponding data residuals. Finally, we evaluate model uncertainties and residual distributions for each cluster. To illustrate the potential of our approach, we use a particle swarm optimization (PSO) algorithm to obtain an ensemble of 2D layer-based resistivity models from a synthetic data example and a field data set collected in Loon-Plage, France. Our strategy performs well for both synthetic and field data and allows us to extract different plausible model scenarios with their associated uncertainties and data residual distributions. Although we demonstrate our workflow using 2D ERT data and a PSObased inversion approach, the proposed strategy is general and can be adapted to analyze model ensembles generated from other kinds of geophysical data and using different global inversion approaches. KW - Near-surface geophysics KW - Electrical resistivity tomography KW - Non-uniqueness KW - Global inversion KW - Particle swarm optimization KW - Ensemble KW - analysis Y1 - 2021 U6 - https://doi.org/10.1016/j.jappgeo.2021.104512 SN - 0926-9851 SN - 1879-1859 VL - 196 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Klose, Tim A1 - Guillemoteau, Julien A1 - Vignoli, Giulio A1 - Tronicke, Jens T1 - Laterally constrained inversion (LCI) of multi-configuration EMI data with tunable sharpness JF - Journal of applied geophysics N2 - Frequency-domain electromagnetic (FDEM) data are commonly inverted to characterize subsurface geoelectrical properties using smoothness constraints in 1D inversion schemes assuming a layered medium. Smoothness constraints are suitable for imaging gradual transitions of subsurface geoelectrical properties caused, for example, by varying sand, clay, or fluid content. However, such inversion approaches are limited in characterizing sharp interfaces. Alternative regularizations based on the minimum gradient support (MGS) stabilizers can, instead, be used to promote results with different levels of smoothness/sharpness selected by simply acting on the so-called focusing parameter. The MGS regularization has been implemented for different kinds of geophysical data inversion strategies. However, concerning FDEM data, the MGS regularization has only been implemented for vertically constrained inversion (VCI) approaches but not for laterally constrained inversion (LCI) approaches. We present a novel LCI approach for FDEM data using the MGS regularization for the vertical and lateral direction. Using synthetic and field data examples, we demonstrate that our approach can efficiently and automatically provide a set of model solutions characterized by different levels of sharpness and variable lateral consistencies. In terms of data misfit, the obtained set of solutions contains equivalent models allowing us also to investigate the non-uniqueness of FDEM data inversion. KW - frequency-domain electromagnetics KW - laterally constrained inversion KW - minimum gradient support regularization KW - peat characterization Y1 - 2022 U6 - https://doi.org/10.1016/j.jappgeo.2021.104519 SN - 0926-9851 VL - 196 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Stolterfoht, Martin A1 - Grischek, Max A1 - Caprioglio, Pietro A1 - Wolff, Christian Michael A1 - Gutierrez-Partida, Emilio A1 - Peña-Camargo, Francisco A1 - Rothhardt, Daniel A1 - Zhang, Shanshan A1 - Raoufi, Meysam A1 - Wolansky, Jakob A1 - Abdi-Jalebi, Mojtaba A1 - Stranks, Samuel D. A1 - Albrecht, Steve A1 - Kirchartz, Thomas A1 - Neher, Dieter T1 - How to quantify the efficiency potential of neat perovskite films BT - Perovskite semiconductors with an implied efficiency exceeding 28% T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Perovskite photovoltaic (PV) cells have demonstrated power conversion efficiencies (PCE) that are close to those of monocrystalline silicon cells; however, in contrast to silicon PV, perovskites are not limited by Auger recombination under 1-sun illumination. Nevertheless, compared to GaAs and monocrystalline silicon PV, perovskite cells have significantly lower fill factors due to a combination of resistive and non-radiative recombination losses. This necessitates a deeper understanding of the underlying loss mechanisms and in particular the ideality factor of the cell. By measuring the intensity dependence of the external open-circuit voltage and the internal quasi-Fermi level splitting (QFLS), the transport resistance-free efficiency of the complete cell as well as the efficiency potential of any neat perovskite film with or without attached transport layers are quantified. Moreover, intensity-dependent QFLS measurements on different perovskite compositions allows for disentangling of the impact of the interfaces and the perovskite surface on the non-radiative fill factor and open-circuit voltage loss. It is found that potassium-passivated triple cation perovskite films stand out by their exceptionally high implied PCEs > 28%, which could be achieved with ideal transport layers. Finally, strategies are presented to reduce both the ideality factor and transport losses to push the efficiency to the thermodynamic limit. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1434 KW - non-radiative interface recombination KW - perovskite solar cells KW - photoluminescence Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-516622 SN - 1866-8372 IS - 17 ER - TY - JOUR A1 - Stolterfoht, Martin A1 - Grischek, Max A1 - Caprioglio, Pietro A1 - Wolff, Christian Michael A1 - Gutierrez-Partida, Emilio A1 - Peña-Camargo, Francisco A1 - Rothhardt, Daniel A1 - Zhang, Shanshan A1 - Raoufi, Meysam A1 - Wolansky, Jakob A1 - Abdi-Jalebi, Mojtaba A1 - Stranks, Samuel D. A1 - Albrecht, Steve A1 - Kirchartz, Thomas A1 - Neher, Dieter T1 - How to quantify the efficiency potential of neat perovskite films BT - Perovskite semiconductors with an implied efficiency exceeding 28% JF - Advanced Materials N2 - Perovskite photovoltaic (PV) cells have demonstrated power conversion efficiencies (PCE) that are close to those of monocrystalline silicon cells; however, in contrast to silicon PV, perovskites are not limited by Auger recombination under 1-sun illumination. Nevertheless, compared to GaAs and monocrystalline silicon PV, perovskite cells have significantly lower fill factors due to a combination of resistive and non-radiative recombination losses. This necessitates a deeper understanding of the underlying loss mechanisms and in particular the ideality factor of the cell. By measuring the intensity dependence of the external open-circuit voltage and the internal quasi-Fermi level splitting (QFLS), the transport resistance-free efficiency of the complete cell as well as the efficiency potential of any neat perovskite film with or without attached transport layers are quantified. Moreover, intensity-dependent QFLS measurements on different perovskite compositions allows for disentangling of the impact of the interfaces and the perovskite surface on the non-radiative fill factor and open-circuit voltage loss. It is found that potassium-passivated triple cation perovskite films stand out by their exceptionally high implied PCEs > 28%, which could be achieved with ideal transport layers. Finally, strategies are presented to reduce both the ideality factor and transport losses to push the efficiency to the thermodynamic limit. KW - non-radiative interface recombination KW - perovskite solar cells KW - photoluminescence Y1 - 2020 U6 - https://doi.org/10.1002/adma.202000080 SN - 0935-9648 SN - 1521-4095 VL - 32 IS - 17 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim ER -