TY - JOUR A1 - Kulow, Anicó A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Emmerling, Franziska A1 - Hampel, S. A1 - Fittschen, UEA A1 - Streli, C. A1 - Radtke, Martin T1 - Reconstruction for coded aperture full-field x-ray fluorescence imaging N2 - X-ray fluorescence imaging is a well-established tool in materials characterization. In this work, we present the adaption of coded aperture imaging to full-field X-ray fluorescence imaging at the synchrotron. Coded aperture imaging has its origins in astrophysics, and has several advantages: Coded apertures are relatively easy to fabricate, achromatic, allow a high photon throughput, and high angular acceptance. Coded aperture imaging is a two-step-process, consisting of the measurement process and a reconstruction step. Different programs have been written, for the raytracing/forward projection and the reconstruction. Experiments with coded aperture in combination with a Color X-ray Camera and an energy-dispersive area detector, have been conducted at the BAMline. Measured samples were successfully reconstructed, and gave a 9.1-fold increase in count rate compared to a polycapillary optic. KW - Synchrotron KW - BAMline KW - Coded Aperture PY - 2022 SN - 1097-0002 VL - 65 SP - 57 EP - 70 PB - Cambridge University Press CY - Cambridge AN - OPUS4-56350 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bothe, Martin A1 - Emmerling, Franziska A1 - Pretsch, Thorsten T1 - Poly(ester urethane) with varying polyester chain length: Polymorphism and shape-memory behavior N2 - The swelling, viscoelastic, and mechanical behavior of phase-segregated poly(ester urethane) (PEU) block copolymers, composed of 4,4'-methylenediphenyl diisocyanate, 1,4-butanediol as a chain extender, and crystallizable poly(1,4-butylene adipate) (PBA) with molecular weights between 1330 and 4120 g mol-1, are investigated. Wide-angle X-ray scattering (WAXS) is employed to study the overall PEU crystallinity, which increases from 8.6 to 13.6% at higher PBA contents. The existence of two crystalline, polymorphic PBA phases, a thermodynamically stable α phase and a metastable β phase, is confirmed by further WAXS measurements. Calorimetric and thermomechanical investigations give evidence for controllable PBA polymorphic behavior. The crystallization conditions, like the cooling rate, affect the emerging polymorphic mixture, whereas the storage conditions either promote or inhibit the polymorphic (β to α) transition. The introduced concepts represent a new approach for gaining control over programmable thermo­responsiveness, which may be transferable to other shape-memory polymers with polymorphic switching segments. KW - Shape-memory polymers KW - Stimuli-sensitive polymers KW - Poly(ester urethane) KW - Polymorphism PY - 2013 DO - https://doi.org/10.1002/macp.201300464 SN - 1022-1352 SN - 1521-3935 VL - 214 IS - 23 SP - 2683 EP - 2693 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-29892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radtke, Martin T1 - Materials research with synchrotron radiation N2 - Synchrotron radiation sources with their unique properties in terms of intensity, polarization and adjustability offer a wide range of possibilities in materials research. A basic introduction about the creation and special properties of synchrotron radiation will be given. Examples of current work at BAMline, the high-energy measuring facility of the Federal Institute for Materials Research and Testing at the synchrotron BESSY, are used to illustrate the possibilities and limitations of existing measuring methods. It will be shown how the formation of corrosion layers can be tracked, how the abrasion of implants leads to the introduction of heavy metals into the surrounding bone matrix and how the detection of smallest impurities in gold is possible by optimizing the measuring conditions. Finally, an outlook at the hardware and software developments to be expected in the coming years is given. T2 - INCT-FNA Symposium 2019 CY - Niteroi, Brazil DA - 27.05.2019 KW - Synchrotron KW - XRF KW - XANES KW - EXAFS KW - TXRF KW - Color X-ray Camera PY - 2019 AN - OPUS4-48897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cakir, Cafer Tufan A1 - Piotrowiak, T. A1 - Reinholz, Uwe A1 - Ludwig, A. A1 - Emmerling, Franziska A1 - Streli, C. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin T1 - Exploring the Depths of Corrosion: A Novel GE-XANES Technique for Investigating Compositionally Complex Alloys N2 - In this study, we propose the use of nondestructive, depth-resolved, element-specific characterization using grazing exit X-ray absorption near-edge structure spectroscopy (GE-XANES) to investigate the corrosion process in compositionally complex alloys (CCAs). By combining grazing exit X-ray fluorescence spectroscopy (GE-XRF) geometry and a pnCCD detector, we provide a scanning-free, nondestructive, depth-resolved analysis in a sub-micrometer depth range, which is especially relevant for layered materials, such as corroded CCAs. Our setup allows for spatial and energy-resolved measurements and directly extracts the desired fluorescence line, free from scattering events and other overlapping lines. We demonstrate the potential of our approach on a compositionally complex CrCoNi alloy and a layered reference sample with known composition and specific layer thickness. Our findings indicate that this new GE-XANES approach has exciting opportunities for studying surface catalysis and corrosion processes in real-world materials. KW - Degradation mechanisms KW - Grazin exit XANES KW - Depth resolved XANES KW - Compositional complex alloys KW - Corrosion PY - 2023 DO - https://doi.org/10.1021/acs.analchem.3c00404 VL - 95 SP - 4810 EP - 4818 PB - ACS Publications AN - OPUS4-57823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Berger, J. A1 - Zahedi-Azad, S. A1 - Voss, H. A1 - Ernst, O.C. A1 - Hammerschmidt, R. A1 - Boeck, T. A1 - Martin, J. A1 - Bonse, J. A1 - Krüger, J. A1 - Schmid, M. T1 - CuInSe2-based micro-concentrator solar cells fabricated from In islands grown by laser-assisted MO-CVD N2 - Micro-concentrator solar cells offer a promising route for reducing material usage in photovoltaics. For Cu(In,Ga)Se2, multiple micro-concentrator manufacturing methods have already been evaluated. All of them involve either high preparation complexity or post-processing to recycle unused precursor or absorber materials. In this work, a new method using laser-assisted metal-organic chemical vapor deposition (LA-MOCVD) was applied to directly grow arrays of indium micro-islands. These arrays are examined and further processed to CuInSe2 micro-solar cell arrays. The geometry and morphology of the islands were investigated and compared before and after absorber formation. The investigation shows that the absorber growth is limited to the vertical direction normal to the substrate surface and that the starting morphology is preserved. Furthermore, the absorber island arrays are processed into micro-modules and operational solar cells are achieved as a proof of principle. These not yet optimized arrays reach a conversion efficiency of 0.65% under 1 sun illumination. Under 17 suns of light concentration, the efficiency gain is between 60 and 250%. This work demonstrates the method's viability for the fabrication of micro-solar cell arrays, with clear potential for achieving higher conversion efficiencies through future optimization. KW - Micro-concentrator solar cells KW - Laser-assisted chemical vapor deposition KW - CISe KW - Bottom-up fabrication KW - Resource efficiency PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656711 DO - https://doi.org/10.1016/j.solmat.2026.114284 SN - 0927-0248 VL - 301 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-65671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tannenberg, Robert A1 - Tscheuschner, Georg A1 - Raab, Christopher A1 - Flemig, Sabine A1 - Döring, Sarah A1 - Ponader, Marco A1 - Thurmann, Melinda A1 - Paul, Martin A1 - Weller, Michael G. T1 - Simplified Sample Preparation and Lateral Flow Immunoassay for the Detection of Plant Viruses N2 - Lateral flow immunoassays (LFAs) are widely used for on-site testing; however, their use for the rapid detection of plant viruses in the field is often limited by inconvenient sample preparation. Here, we present a new sampling method and a simplified dipstick LFA format for the detection and monitoring of cowpea chlorotic mottle virus (CCMV) as a model plant pathogen. The assay employs a monoclonal mouse antibody for capture and a poly-clonal rabbit antibody conjugated to 80 nm gold nanoparticles for detection. Conventional sample and conjugate pads are omitted, allowing the test strips to be dipped directly into wells containing plant extract and antibody–gold conjugate. No plastic casing was required, which could lead to a reduction in waste. It was shown that CCMV concentrations as low as 3.5 µg/L or 350 pg per sample could be reliably detected in 15 min. Specificity tests confirmed that other plant viruses, cowpea mosaic virus (CPMV) and tobacco mosaic virus (TMV), did not produce false-positive results. In addition, we describe a new method for on-site sampling using a manual punch and a syringe equipped with a frit. This step combines grinding the sample, extraction, filtration, and reconstitution and mixing of the antibody-gold conjugate, enabling the analysis of punched leaf disks without laboratory equipment. When applied to CCMV-infected cowpea plants, the assay revealed systemic infection before visual symptoms became apparent. This work demonstrates that simplified LFAs combined with innovative sampling techniques can provide sensitive, specific, and rapid diagnostics for crop monitoring and support early intervention strategies in agriculture. N2 - Lateral-Flow-Immunoassays (LFAs) werden häufig für Vor-Ort-Tests eingesetzt; ihr Einsatz zum schnellen Nachweis von Pflanzenviren im Feld wird jedoch oft durch eine umständliche Probenvorbereitung eingeschränkt. Hier stellen wir eine neue Probenahmemethode und ein vereinfachtes Dipstick-LFA-Format zum Nachweis und zur Überwachung des Cowpea Chlorotic Mottle Virus (CCMV) als Modellpflanzenpathogen vor. Der Test verwendet einen monoklonalen Maus-Antikörper zur Bindung und einen polyklonalen Kaninchen-Antikörper, der an 80-nm-Goldnanopartikel konjugiert ist, zum Nachweis. Herkömmliche Proben- und Konjugatpads entfallen, sodass die Teststreifen direkt in Vertiefungen getaucht werden können, die Pflanzenextrakt und das Antikörper-Gold-Konjugat enthalten. Es ist keine Kunststoffhülle erforderlich, was zu einer Reduzierung des Abfallaufkommens führen könnte. Es zeigte sich, dass CCMV-Konzentrationen von nur 3,5 µg/L oder 350 pg pro Probe innerhalb von 15 Minuten zuverlässig nachgewiesen werden konnten. Spezifitätstests bestätigten, dass andere Pflanzenviren, das Cowpea Mosaic Virus (CPMV) und das Tobacco Mosaic Virus (TMV), keine falsch-positiven Ergebnisse lieferten. Darüber hinaus beschreiben wir eine neue Methode zur Probenahme vor Ort unter Verwendung eines manuellen Lochers und einer mit einer Fritte ausgestatteten Spritze. Dieser Schritt kombiniert das Zerkleinern der Probe, die Extraktion, die Filtration sowie die Rekonstitution und das Mischen des Antikörper-Gold-Konjugats und ermöglicht so die Analyse der ausgestanzten Blattscheiben ohne Laborausrüstung. Bei der Anwendung an mit CCMV infizierten Augenbohnenpflanzen zeigte der Assay eine systemische Infektion, bevor visuelle Symptome erkennbar wurden. Diese Arbeit zeigt, dass vereinfachte LFAs in Kombination mit innovativen Probenahmetechniken eine sensitive, spezifische und schnelle Diagnostik für die Pflanzenüberwachung bieten und Strategien zur frühzeitigen Intervention in der Landwirtschaft unterstützen können. KW - Point-of-care diagnostics KW - Dipstick immunoassay KW - Pre-symptomatic detection KW - Precision agriculture KW - Integrated pest management KW - Crop health monitoring PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657039 DO - https://doi.org/10.3390/bios16020100 SN - 2079-6374 VL - 16 IS - 2 SP - 1 EP - 16 PB - MDPI AG CY - Basle, Switzerland AN - OPUS4-65703 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Herder, Martin A1 - Erler, Robert A1 - Rolf, Simone A1 - Fischer, A. A1 - Würth, Christian A1 - Thünemann, Andreas A1 - Kraehnert, R. A1 - Emmerling, Franziska T1 - Mechanistic insights into seeded growth processes of gold nanoparticles N2 - A facile approach for the synthesis of monodisperse gold nanoparticles with radii in the range of 7 to 20 nm is presented. Starting from monodisperse seeds with radii of 7 nm, produced in the first step, the addition of a defined amount of additional precursor material permits distinct size regulation and the realization of predicted nanoparticle sizes. These information were derived from ex- and in situ investigations by comprehensive small angle X-ray scattering (SAXS), X-ray absorption near edge structure (XANES) and UV-Vis data to obtain information on the physicochemical mechanisms. The obtained mechanisms can be transferred to other seeded growth processes. Compared to similar approaches, the presented synthesis route circumvents the use of different reducing or stabilizing agents. The size of resulting nanoparticles can be varied over a large size range presented for the first time without a measurable change in the shape, polydispersity or surface chemistry. Thus, the resulting nanoparticles are ideal candidates for size dependence investigations. KW - Gold nanoparticles KW - SAXS KW - XANES KW - Growth mechanism PY - 2010 DO - https://doi.org/10.1039/c0nr00541j SN - 2040-3364 SN - 2040-3372 VL - 2 IS - 11 SP - 2463 EP - 2469 PB - RSC Publ. CY - Cambridge AN - OPUS4-22346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Emmerling, Franziska A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas T1 - Real-time monitoring of copolymer stabilized growing gold nanoparticles N2 - A great challenge in the production of nanoparticles with defined sizes and properties is to control their growth in situ. We developed a dedicated combined small-angle X-ray scattering (SAXS) and X-ray absorption spectroscopy (XAS) setup to monitor nanoparticle formation in solution. The capabilities of simultaneously deriving particle sizes and oxidation states of atoms/ions are illustrated for the formation of spherical gold nanoparticles by the reduction of hydrogen tetrachloroaureate (HAuCl4). Particles with initial radii of 4.60 ± 0.10 nm and final radii of 5.67 ± 0.10 nm were produced in a levitated droplet with a volume of 4 µL. An ethylene oxide/propylene oxide triblock copolymer PEO-PPO-PEO (Pluronic F-127) functions as reducing agent and colloidal stabilizer. XANES shows in situ how the gold was reduced in the droplet from Au(III) to Au(0), and simultaneously SAXS recorded the size distribution of the formed nanoparticles. It is shown that the final particle number is reached quickly. Thereafter, only the particles’ sizes increase. Comparison of XANES and SAXS shows that the quantity of Au(0) is higher than the quantity of gold located in the nanoparticles while the particles are growing. Finally, all the Au(0) is found in the nanoparticles. We tentatively attribute this finding to the pseudo crown ether effect of the polymer surfactant that kinetically stabilizes gold atoms when formed from gold ions within their protecting cavity. A simple “burst” mechanism for the gold nanoparticle formation is the consequence. The possibility of an inhomogeneous particles structure with an enhanced density near the particle surface is discussed. PY - 2010 DO - https://doi.org/10.1021/la903829q SN - 0743-7463 SN - 1520-5827 VL - 26 IS - 8 SP - 5889 EP - 5894 PB - American Chemical Society CY - Washington, DC AN - OPUS4-21223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Kraehnert, R. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Thünemann, Andreas A1 - Emmerling, Franziska T1 - New insights of the nucleation and growth process of gold nanoparticles via in situ coupling of SAXS and XANES N2 - Although metallic nanoparticles play an important role in the area of nanotechnology, a coherent mechanistic explanation for the evolution of the particles during their chemical synthesis has not yet been provided in many cases. To gain a profound understanding of the growth mechanism of colloidal nanoparticles, new approaches using Small Angle X-Ray Scattering (SAXS) combined with X-ray absorption near-edge structure (XANES) are presented. This combination allows for insights into two prominent syntheses routes of gold nanoparticles (GNP): The 'slow' reaction using sodium citrate (30-90 min) as a reducing agent and the 'fast' reaction employing NaBH4 (within few seconds). In the first case data derived with the coupled XANES and SAXS suggests a four-step particle formation mechanism. For the second system a time resolution in the order of 100-200 ms was achieved by coupling a common laboratory SAXS instrument with a microstructured mixer, which allows data acquisition in a continuous-flow mode. The results indicate a coalescence driven growth process. Based on the capabilities to deduce the size, number and polydispersity of the particles, the results of both methods enable the development of mechanistic schemes explaining the different phases of particle formation and growth, thus providing a basis for improved control over the synthesis processes. KW - SAXS KW - XANES KW - Nanoparticle formation PY - 2010 DO - https://doi.org/10.1088/1742-6596/247/1/012051 SN - 1742-6588 SN - 1742-6596 VL - 247 IS - 1 SP - 012051-1 - 012051-10 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-22684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Martin A1 - Gregor, Christian A1 - Schulz, Michael A1 - Szczepaniak, Mariusz A1 - Mair, Georg W. T1 - Entwickelt und validiert - Probengeometrie zur Untersuchung von gewickelten Faserverbundproben N2 - Durch die beschriebene, auf eine Umfangsbelastung ausgelegte Probengeometrie werden Fertigung und Einsatz von Druckbehältern nachempfunden. Dafür wurden bereits bestehende Probenformen überarbeitet, um im Probenkörper eine unidirektionale Zugbelastung zu erzeugen. Da die endgültigen Eigenschaften von faserverstärktem Kunststoff erst in der Fertigung entstehen, sind gleiche Fertigungsbedingungen von Proben und Bauteilen wichtig. Die hier vorgestellte Probe verspricht dadurch eine gute Eignung für den Einsatz bei Untersuchungen zum Zeitstandsverhalten. KW - Faserverstärkte Kunststoffe (FVK) KW - Druckbehälter KW - Zeitstand KW - Zugprobe PY - 2012 SN - 1865-4819 VL - 5 SP - 44 EP - 49 PB - Springer Vieweg, Springer Fachmedien Wiesbaden GmbH CY - Wiesbaden AN - OPUS4-26893 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -