TY - JOUR A1 - Westwood, S. A1 - Josephs, R. A1 - Choteau, T. A1 - Daireaux, A. A1 - Wielgosz, R. A1 - Davies, S. A1 - Moad, M. A1 - Chan, B. A1 - Munoz, A. A1 - Conneely, P. A1 - Ricci, M. A1 - Do Rego, E.C.P. A1 - Garrido, B.C. A1 - Violante, F.G.M. A1 - Windust, A. A1 - Dai, X. A1 - Huang, T. A1 - Zhang, W. A1 - Su, F. A1 - Quan, C. A1 - Wang, H. A1 - Lo, M. A1 - Wong, W. A1 - Gantois, F. A1 - Lalerle, B. A1 - Dorgerloh, Ute A1 - Koch, Matthias A1 - Klyk-Seitz, Urszula-Anna A1 - Pfeifer, Dietmar A1 - Philipp, Rosemarie A1 - Piechotta, Christian A1 - Recknagel, Sebastian A1 - Rothe, Robert A1 - Yamazaki, T. A1 - Zakaria, O. B. A1 - Castro, E. A1 - Balderas, M. A1 - González, N. A1 - Salazar, C. A1 - Regalado, L. A1 - Valle, E. A1 - Rodríguez, L. A1 - Laguna, L.Á.. A1 - Ramírez, P. A1 - Avila, M. A1 - Ibarra, J. A1 - Valle, L. A1 - Arce, M. A1 - Mitani, Y. A1 - Konopelko, L. A1 - Krylov, A. A1 - Lopushanskaya, E. A1 - Lin, T.T. A1 - Liu, Q. A1 - Kooi, L.T. A1 - Fernandes-Whaley, M. A1 - Prevoo-Franzsen, D. A1 - Nhlapo, N. A1 - Visser, R. A1 - Kim, B. A1 - Lee, H. A1 - Kankaew, P. A1 - Pookrod, P. A1 - Sudsiri, N. A1 - Shearman, K. A1 - Gören, A.C. A1 - Bilsel, G. A1 - Yilmaz, H. A1 - Bilsel, M. A1 - Cergel, M. A1 - Coskun, F.G. A1 - Uysal, E. A1 - Gündüz, S. A1 - Ün, I. A1 - Warren, J. A1 - Bearden, D.W. A1 - Bedner, M. A1 - Duewer, D.L. A1 - Lang, B.E. A1 - Lippa, K.A. A1 - Schantz, M.M. A1 - Sieber, J.R. T1 - Final report on key comparison CCQM-K55.c (L-(+)-Valine): Characterization of organic substances for chemical purity N2 - KEY COMPARISON Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.c, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2012. Twenty National Measurement Institutes or Designated Institutes and the BIPM participated. Participants were required to assign the mass fraction of valine present as the main component in the comparison sample for CCQM-K55.c. The comparison samples were prepared from analytical grade L-valine purchased from a commercial supplier and used as provided without further treatment or purification. Valine was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of low structural complexity [molecular weight range 100–300] and high polarity (pKOW > –2). The KCRV for the valine content of the material was 992.0 mg/g with a combined standard uncertainty of 0.3 mg/g. The key comparison reference value (KCRV) was assigned by combination of KCRVs assigned from participant results for each orthogonal impurity class. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 1 mg/g to 6 mg/g when using mass balance based approaches alone, 2 mg/g to 7 mg/g using quantitative 1H NMR (qNMR) based approaches and from 1 mg/g to 2.5 mg/g when a result obtained by a mass balance method was combined with a separate qNMR result. The material provided several analytical challenges. In addition to the need to identify and quantify various related amino acid impurities including leucine, isoleucine, alanine and a-amino butyrate, care was required to select appropriate conditions for performing Karl Fischer titration assay for water content to avoid bias due to in situ formation of water by self-condensation under the assay conditions. It also proved to be a challenging compound for purity assignment by qNMR techniques. There was overall excellent agreement between participants in the identification and the quantification of the total and individual related structure impurities, water content, residual solvent and total non-volatile content of the sample. Appropriate technical justifications were developed to rationalise observed discrepancies in the limited cases where methodology differences led to inconsistent results. The comparison demonstrated that to perform a qNMR purity assignment the selection of appropriate parameters and an understanding of their potential influence on the assigned value is critical for reliable implementation of the method, particularly when one or more of the peaks to be quantified consist of complex multiplet signals. PY - 2014 DO - https://doi.org/10.1088/0026-1394/51/1A/08010 SN - 0026-1394 SN - 1681-7575 VL - 51 SP - 08010, 1 EP - 44 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-31072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - DeRose, P.C. A1 - Wang, L. A1 - Gaigalas, A.K. A1 - Kramer, G.W. A1 - Resch-Genger, Ute A1 - Panne, Ulrich ED - Resch-Genger, Ute ED - O.S. Wolfbeis, T1 - Need for and metrological approaches towards standardization of fluorescence measurements from the view of national metrology institutes N2 - The need for standardization in fluorescence measurements to improve quality assurance and to meet regulatory demands is addressed from the viewpoint of National Metrology Institutes (NMIs). Classes of fluorescence standards are defined, including instrument calibration standards for the determination and correction of instrument bias, application-specific standards based on commonly used fluorescent labels, and instrument validation standards for periodic checks of instrument performance. The need for each class of standard is addressed and on-going efforts by NMIs and others are described. Several certified reference materials (CRMs) that have recently been developed by NMIs are highlighted. These include spectral correction standards, developed independently by both NIST and BAM (Germany), and fluorescence intensity standards for flow cytometry, developed by NIST. In addition, future activities at both institutes are addressed such as the development of day-to-day intensity standards. KW - Fluorescence spectroscopy KW - Quality assurance KW - Calibration KW - Standard KW - Comparability KW - Quantification KW - Traceability KW - Radiometry KW - Emission standard KW - Fluorescent glass KW - Spectral correction KW - Spectral fluorescence standard PY - 2008 SN - 978-3-540-75206-6 DO - https://doi.org/10.1007/4243_2008_049 SN - 1617-1306 N1 - Serientitel: Springer Series on Fluorescence – Series title: Springer Series on Fluorescence VL - 5 IS - Part A SP - 33 EP - 62 PB - Springer AN - OPUS4-18996 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, M. A1 - Zhang, T. A1 - Wang, J. A1 - Cheng, Z. A1 - Yang, J. A1 - Qiao, X. A1 - Wen, J. A1 - Resch-Genger, Ute A1 - Ou, J. T1 - Fluorescence temperature sensing of NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ nanoparticles at low and high temperatures N2 - NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ upconversion nanoparticles (UCNPs) were prepared using a solvothermal method, and the effects of key factors such as the content of sensitiser Nd 3+ and Yb3+ on their luminescence properties were investigated. The nanoparticles are homogeneous in size and well dispersed. Under 808 nm excitation, it can produce strong upconversion fluorescence. At the same time, the nanoparticles have good temperature-sensing properties at the thermally coupled energy levels of 700 nm and 646 nm for Tm3+. Using its fluorescence intensity ratio (FIR), accurate temperature measurements can be performed, and it has been found that it exhibits different temperature sensing properties in low and high-temperature regions. The maximum relative sensitivity was found to be 0.88% K-1 and 1.89% K-1 for the lowtemperature region of 285 K-345 K and the high-temperature region of 345 K-495 K. The nanoparticles were applied to the internal temperature measurement of lithium batteries and the actual high-temperature environment, respectively, and were found to have good temperature measurementt performance. KW - Fluorescence KW - Sensor KW - Temperature KW - Ratiometric KW - Lanthanide KW - Quantum yield KW - Integrating sphere spectroscopy KW - Absolute fluorescence KW - Quality assurance KW - Nano KW - Particle KW - Application KW - Upconversion nanoparticle PY - 2022 DO - https://doi.org/10.1088/1361-6528/ac84e4 SN - 1361-6528 VL - 33 IS - 34 SP - 1 EP - 15 PB - IOP Publishing CY - Bristol AN - OPUS4-55454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rezvani, A. A1 - Wang, Z. A1 - Wegner, Karl David A1 - Soltanmoradi, H. A1 - Kichigin, A. A1 - Zhou, X. A1 - Gantenberg, T. A1 - Schram, J. A1 - Zubiri, B. A. A1 - Spiecker, E. A1 - Walter, J. A1 - Resch-Genger, Ute A1 - Segets, D. T1 - Separation of Indium Phosphide/Zinc Sulfide Core−Shell Quantum Dots from Shelling Byproducts through Multistep Agglomeration N2 - Semiconductor quantum dots (QDs) possess unique electronic and optical properties, making them promising candidates for applications in lightemitting diodes, solar cells, bioimaging, and photocatalysis. Precise control over their size, shape, and chemical and electronic structure is crucial to ensure the desired functional properties and optimize device performance. However, challenges in QD synthesis and post-synthesis modification persist, especially in large-scale production. This study addresses the classification of QDs synthesized in a tubular flow reactor consisting of a mixture of the desired InP/ZnS core−shell QDs and QDs made from the shell material, i.e., here ZnS QDs formed as a byproduct during the formation step of the ZnS shell. The homogeneous nucleation of ZnS nanoparticles from the shelling material introduces a heterogeneity in size and composition and affects the optical properties of the resulting QDs. To address this issue, we developed a size-selective agglomeration (SSA) technique by incrementally introducing ethanol as a poor solvent and classified the synthesized QDs into 13 distinct fractions. These 13 fractions are sorted into three distinct groups: (i) larger InP/ZnS QDs, (ii) a combination of smaller InP/ZnS QDs and larger ZnS QDs, and (iii) predominant ZnS QDs with some very tiny InP/ZnS QDs. The comprehensive characterization of the fractions was conducted using UV−visible absorption spectroscopy, photoluminescence spectroscopy, high-resolution scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, total reflection X-ray fluorescence, and analytical ultracentrifugation. We could demonstrate that our method effectively separated unwanted ZnS QDs from the target InP/ZnS QDs. In addition, the fractions enriched in smaller InP/ZnS QDs exhibited a higher photoluminescence quantum yield compared to the fractions with larger QDs. This demonstrates the efficacy of SSA in finetuning the composition of QD mixtures produced on a larger scale to improve their functional properties. This approach provides fundamental understanding toward the development of a scalable two-dimensional classification process for such ultrasmall nanoparticles by particle size and composition. KW - Quality assurance KW - Reference material KW - Nano KW - Particle KW - Quantum dot KW - Synthesis KW - Flow reactor KW - InP KW - Shell KW - ZnS KW - Surface chemistry KW - Method KW - Fluorescence KW - Quantum yield KW - TEM PY - 2025 DO - https://doi.org/10.1021/acsnano.4c18530 SN - 1936-086X VL - 19 IS - 20 SP - 19080 EP - 19094 PB - ACS Publications AN - OPUS4-63215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, X. T1 - Gold nanoparticle-catalyzed uranine reduction N2 - Gold nanoparticles (AuNPs) can catalyze the decolorization of organic dyes in the presence of sodium borohydride (NaBH4), which can be utilized for sensitive optical signaling. Here, we monitor the catalytic reduction of a fluorescent substrate, exemplarily chosen uranine, by AuNPs serving as nanocatalysts by absorption and fluorescence spectroscopy. Dye reduction is accompanied by dramatic changes in the absorption and fluorescence properties of uranine. As proposed reaction mechanism, we assume electron transfer between uranine and NaBH4 through the AuNPs nanocatalysts which is currently investigated also by time-resolved fluorescence and detailed spectroscopic studies of the influence of pH, NaBH4, and AuNPs on these effects. As ultimate goal, a model reporter platform with colorimetric andfluorometric signaling is anticipated for the detection of different analytes by coating AuNPs with affinity ligands such as antibodies and aptamers and and special separation methods. T2 - Anakon 2015 CY - Graz, Austria DA - 23.03.2015 KW - Fluorescence lifetime KW - Uranine KW - Nanoparticle KW - Surfactant PY - 2015 AN - OPUS4-38957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moll, J. A1 - Wang, Cui A1 - Päpcke, A. A1 - Förster, C. A1 - Resch-Genger, Ute A1 - Lochbrunner, S. A1 - Heinze, K. T1 - Green Light Activation of Push-Pull Ruthenium(II) Complexes N2 - Synthesis, characterization, electrochemistry, and photophysics of novel homo- and heteroleptic ruthenium(II) complexes [Ru(cpmp)2] 2+ (22+) and [Ru(cpmp)(ddpd)]2+ (32+) bearing the tridentate ligands 6,2’’-carboxypyridyl-2,2’-methylamine-pyridylpyridine (cpmp) and N,N’-dimethyl-N,N’-dipyridin-2-ylpyridine-2,6-diamine (ddpd) are reported. The complexes possess one (32+) or two (22+) electron-deficient dipyridyl ketone fragments as electron accepting sites enabling intraligand charge transfer (ILCT), ligand-toligand charge transfer (LL’CT) and low-energy metal-to-ligand charge transfer (MLCT) absorptions. The latter peak around 544 nm (green light). 22+ shows 3MLCT phosphorescence in the red to near-infrared spectral region at room temperature in deaerated acetonitrile solution with an emission quantum yield of 1.3 % and a 3MLCT lifetime of 477 ns, while 3 2+ is much less luminescent. This different behaviour is ascribed to the energy gap law and the shape of the parasitic excited 3MC state potential energy surface. This study highlights the importance of the excited state energies and geometries for the actual excited state dynamics. Aromatic and aliphatic amines reductively quench the excited state of 22+ paving the way to photocatalytic applications using low-energy green light as exemplified with the green-light sensitized thiol-ene click reaction. KW - Green light excitation KW - Ruthenium(II) complexes KW - Phosphorescence KW - MLCT KW - Photoinduced electron transfer PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506759 DO - https://doi.org/10.1002/chem.202000871 SP - 1 EP - 13 PB - Wiley-VCH Verlag AN - OPUS4-50675 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Y. A1 - Ulbricht, Alexander A1 - Schmidt, F. A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Schwitalla, A.D. T1 - Micro-CT analysis and mechanical properties of low dimensional CFR-PEEK specimens additively manufactured by material extrusion N2 - Material extrusion of thermoplastic polymers enables the realization of complex specific designs with high performance composites. The present study aims at evaluating the mechanical properties of carbon fiberreinforced semi-crystalline thermoplastic polymer polyether ether ketone (CFR-PEEK) manufactured by material extrusion and correlating them with results obtained by micro-CT. Samples in the shape of small bars were provided by Kumovis (Munich, Germany). The determination of surface roughness and density was followed by three-point bending tests. To reveal the pore distribution as well as the fusion quality of CFR PEEK when applied with external forces, micro-CT scans were performed with an X-ray microscope before and after the mechanical test to localize the sites where the fracture is generated. The density of CFR-PEEK bars indicated that they had superior mechanical properties compared with our previous study on unfilled 3D printed PEEK (bending modulus: (5.4 ± 0.5) GPa vs. (1.05 ± 0.05) GPa to (1.48 ± 0.10) GPa; bending strength: (167 ± 11) MPa vs. (51 ± 15) to (193 ± 7) MPa). Micro-CT analyses revealed the local 3D-distribution of voids. Voids of 30 μm diameter are nearly spherical and make up the main part of the total porosity. The larger the voids, the more they deviate from a spherical shape. Significant lack-of-fusion voids are located between the deposited filaments. By growing and merging, they act as seeds for the forming fracture line in the region of the flexural specimens where the maximum local tensile stresses occurred under bending load. Our work provides a detailed analysis of printed PEEK with fiber additive and relates this with mechanical properties. KW - CFR-PEEK KW - Material extrusion (MEX) KW - FFF KW - Surface topography KW - Bending property KW - Micro-CT PY - 2023 DO - https://doi.org/10.1016/j.jmbbm.2023.106085 SN - 1751-6161 VL - 146 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-58112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, Alan A1 - Moschetti, Michael A1 - Miskovic, David A1 - Wei, Tao A1 - Ionescu, Mihail A1 - Wang, Zhiyang A1 - Palmer, Tim A1 - Bhattacharyya, Dhriti A1 - He, Peidong A1 - Li, Xiaopeng A1 - Gludovatz, Bernd A1 - Ferry, Michael T1 - Improved irradiation resistance of a low activation refractory medium entropy alloy, VCrFeW0.2, for fusion applications demonstrated by micro-tensile testing N2 - An, as cast, VCrFeW0.2 refractory medium entropy alloy (RMEA) was designed for fusion reactor divertor applications, focusing on reduced cost, low activation and compositional stability (low transmutation rates). The as-cast alloy was irradiated to a fluence of 5.6 × 10^17 ions/cm^2 at room temperature with 5 MeV helium ions whose energy have been uniformly attenuated to 0.4 MeV and 5 MeV via energy degradation device prior to sample irradiation. Pre and post irradiation, its mechanical properties were evaluated micro-tensile testing. Prior to irradiation, the VCrFeW0.2 alloy demonstrated good strength and ductility, with a yield strength of 1464 MPa and strain to UTS (\sigma_UTS) of 4.6 %, maintaining comparable strength to pure tungsten (1403 MPa) but with greater strain to UTS (1.3 %). Post irradiation, the VCrFeW0.2 alloy exhibited remarkable damage resistance; its strength increased by only ∼160 MPa, and it retained strain to UTS with a \sigma_UTS of 2.9 %. It performed better than pure tungsten tested under identical irradiation conditions where there was ∼1800 MPa increase in yield strength and a complete loss of plasticity. The micro-tensile results were supported by nanoindentation tests and Vickers hardness testing was also undertaken to show the yield strength values are representative of macro scale, bulk behavior. TEM and comparison with existing literature on RMEA/RHEA are presented here to understand the reason for difference in performance between VCrFeW0.2 alloy and pure tungsten. KW - Refractory medium entropy alloys KW - Fusion reactor materials KW - Irradiation resistance KW - Micro-tensile testing KW - Helium ion damage PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645322 DO - https://doi.org/10.1016/j.ijrmhm.2025.107481 SN - 0263-4368 VL - 134 SP - 1 EP - 16 PB - Elsevier Ltd. CY - Netherlands AN - OPUS4-64532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Cui A1 - Otto, S. A1 - Dorn, M. A1 - Kreidt, E. A1 - Lebon, J. A1 - Sršan, L. A1 - Di Martino-Fumo, P. A1 - Gerhards, M. A1 - Seitz, M. A1 - Resch-Genger, Ute A1 - Heinze, K. T1 - Deuterierter molekularer Rubin mit Rekord-Lumineszenzquantenausbeute N2 - Der kürzlich publizierte Chrom(III)-Komplex 13+([Cr(ddpd)2]3+) zeigt in wässriger Lösung unter Umgebungsbedingungen eine bemerkenswert starke Emission im nahen Infrarot-Bereich mit einer Emissionswellenlänge von 775 nm. Geschicktes Ligandendesign verhindert strahlungslose Desaktivierungsprozesse wie Photosubstitution, Rück-Intersystem-Crossing und trigonale Verzerrungen und führt damit zu einer Phosphoreszenzlebensdauer im Bereich von Mikrosekunden. In Abwesenheit von Energieakzeptoren wie molekularem Sauerstoff verbleibt nur Energietransfer zu hochenergetischen Oszillatoren der Liganden und Lösungsmittelmoleküle wie beispielsweise OH- und CH-Streckschwingungen als Desaktivierungspfad. Selektive Deuterierung der ddpd-Liganden und der Lösungsmittel l-sst die Effizienz dieser Oszillatoren bei der Desaktivierung angeregter Zustände erkennbar werden. Gezieltes Ausschalten dieser Relaxationspfade führt zu einer Quantenausbeute von 30% und einer Lebensdauer von 2.3 Millisekunden bei Raumtemperatur in Lösung – Rekordwerte für einen Komplex, der auf dem Element Chrom basiert. Diese fundamentalen Erkenntnisse ebnen den Weg für gezieltes Ligandendesign zur Synthese lumineszierender Komplexe mit gut verfügbaren Übergangsmetallen. KW - Cr(III)-Komplex KW - Rekord Luminescence Quantum Ausbeute KW - Abklingzeit PY - 2018 DO - https://doi.org/10.1002/ange.201711350 SN - 1521-3757 VL - 130 IS - 4 SP - 1125 EP - 1130 PB - Wiley-VCH Verlag & Co. KGaA CY - Weinheim AN - OPUS4-45086 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Cui A1 - Reichenauer, F. A1 - Kitzmann, W.R. A1 - Kerzig, Ch. A1 - Heintze, K. A1 - Resch-Genger, Ute T1 - Efficient Triplet-Triplet Annihilation Upconversion Sensitized by a Chromium(III) Complex via an Underexplored Energy Transfer Mechanism N2 - Sensitized triplet-triplet annihilation upconversion (sTTA-UC) mainly relies on precious metal complexes thanks to their high intersystem crossing (ISC) efficiencies, excited state energies, and lifetimes, while complexes of abundant first-row transition metals were only rarely utilized and with often moderate UC quantum yields. [Cr(bpmp)2]3+ (bpmp = 2,6-bis(2-pyridylmethyl)pyridine) containing earth-abundant chromium possesses an absorption band suitable for green light excitation, a doublet excited state energy matching the triplet energy of 9,10-diphenyl anthracene (DPA), a close to millisecond excited state lifetime, and high photostability. Combined ISC and doublet-triplet energy transfer from excited [Cr(bpmp)2]3+ to DPA gives 3DPA with close-to-unity quantum yield. TTA of 3DPA furnishes greento-blue UC with a quantum yield of 12.0 % (close to the theoretical maximum). Sterically less-hindered anthracenes undergo a [4+4] cycloaddition with [Cr(bpmp)2]3+ and green light. KW - Fluorescence KW - Optical probe KW - Sensor KW - ph KW - Quantum yield KW - Quality assurance KW - Cr(III) KW - Lifetime KW - Ligand KW - Theory KW - TTA-UC KW - Energy transfer KW - Upconversion KW - Mechanism KW - Anthracene KW - Photochemistry KW - DFT KW - Cycloaddition KW - Transient absorbtion spectroscopy PY - 2022 DO - https://doi.org/10.1002/anie.202202238 VL - 61 IS - 24 SP - 1 EP - 8 PB - Wiley online library AN - OPUS4-54604 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Otto, S. A1 - Moll, J. A1 - Förster, C. A1 - Geißler, Daniel A1 - Wang, Cui A1 - Resch-Genger, Ute A1 - Heinze, K. T1 - Three-in-One Crystal: The Coordination Diversity of Zinc Polypyridine Complexes N2 - The syntheses, structures, and photophysical properties of two new zinc(II) complexes bearing the tridentate N,N′-dimethyl-N,N′-dipyridin-2-ylpyridine-2,6-diamine (ddpd) ligand are presented. Structural investigations through single-crystal X-ray diffractometry, NMR spectroscopy, and density functional theory calculations revealed a diverse coordination behavior that depends on the counterion. Spectroscopic (UV/Vis and emission spectroscopy) and theoretical techniques (DFT and time-dependent DFT calculations) were employed to explore the photophysical properties of the complexes. KW - Zinc(II) complexes KW - X-ray diffractometry (XRD) KW - NMR spectroscopy KW - Density functional theory (DFT) KW - UV/Vis and emission spectroscopy PY - 2017 DO - https://doi.org/10.1002/ejic.201700948 SN - 1434-1948 SN - 1099-0682 VL - 43 SP - 5033 EP - 5040 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-43274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kalmbach, J. A1 - Wang, Cui A1 - You, Yi A1 - Förster, C. A1 - Schubert, H. A1 - Heinze, K. A1 - Resch-Genger, Ute A1 - Seitz, M. T1 - Near-IR to near-IR upconversion luminescence in molecular chromium ytterbium salts N2 - Upconversion photoluminescence in hetero-oligonuclear metal complex architectures featuring organic ligands is an interesting but still rarely observed phenomenon, despite its great potential from a basic research and application perspective. In this context, a new photonic material consisting of molecular chromium(III) and ytterbium(III) complex Ions was developed that exhibits excitation-power density-dependent cooperative sensitization of the chromium-centered 2E/2T1 phosphorescence at approximately 775 nm after excitation of the ytterbium band 2F7/2!2F5/2 at approximately 980 nm in the solid state at ambient temperature. The upconversion process is insensitive to atmospheric oxygen and can be observed in the presence of water molecules in the crystal lattice. KW - Upconversion KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - NIR KW - Cr(III) KW - Yb(III) complex KW - Crystal KW - Triplet-triplet annihilation KW - Sensitization KW - Light harvesting PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512619 DO - https://doi.org/10.1002/anie.202007200 SN - 1433-7851 SN - 1521-3773 VL - 59 IS - 42 SP - 18804 EP - 18808 PB - Wiley CY - Weinheim AN - OPUS4-51261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xue, Boyang A1 - Wang, Zhangjun A1 - Zhu, Tao A1 - Gu, Yezhen A1 - Sun, Weihong A1 - Chen, Chao A1 - Li, Zhigang A1 - Riedel, Jens A1 - You, Yi T1 - High repetition-rate laser-induced breakdown spectroscopy combined with two-dimensional correlation method for analysis of sea-salt aerosols N2 - Laser-induced breakdown spectroscopy (LIBS) offers a tantalizing glimpse into real-time, on-the-spot aerosol analysis. Yet, the reliance on traditional lasers, with their limitations in energy and frequency, hampers optimal sample handling, dissociation, and excitation. To address those challenges, we propose a novel tactic: utilize a high repetition-rate (rep.-rate) laser with low pulse energy in combination with the two-dimensional correlation (2D-corr.) technique for sea-salt aerosols analyses. By examining the emission patterns from both the laser pulse train and individual pulses, we recognize distinctive analyte-specific rep.-rate responses, which allowed spectral reconstruction of analytes, avoiding background interferences. This discovery enabled the rep.-rate modulation for a 2D-corr. spectroscopy workflow. Consequently, we successfully differentiated between particle-related and air-species-related spectral components, obviating expensive spectrometers or intensified image detectors. For instance, the Na I at 589 nm stemming from aerosols exhibited an entirely different correlation contribution compared to O I at 777 nm, resulting in reconstructed clean aerosol-spectra without spectral peaks originated from air species. This 2D-corr. aerosol LIBS approach shows promising analytical potential streamlining aerosol particle analysis. KW - LIBS KW - Aerosol PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613392 DO - https://doi.org/10.1016/j.sab.2024.107048 SN - 0584-8547 VL - 221 SP - 1 EP - 8 PB - Elsevier AN - OPUS4-61339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stinville, J.C. A1 - Charpagne, M.A. A1 - Maaß, Robert A1 - Proudhon, H. A1 - Ludwig, W. A1 - Callahan, P.G. A1 - Wang, F. A1 - Beyerlein, I.J. A1 - Echlin, M.P. A1 - Pollock, T.M. T1 - Insights into Plastic Localization by Crystallographic Slip from Emerging Experimental and Numerical Approaches N2 - Advanced experimental and numerical approaches are being developed to capture the localization of plasticity at the nanometer scale as a function of the multiscale and heterogeneous microstructure present in metallic materials. These innovative approaches promise new avenues to understand microstructural effects on mechanical properties, accelerate alloy design, and enable more accurate mechanical property prediction. This article provides an overview of emerging approaches with a focus on the localization of plasticity by crystallographic slip. New insights into the mechanisms and mechanics of strain localization are addressed. The consequences of the localization of plasticity by deformation slip for mechanical properties of metallic materials are also detailed. KW - Slip localization KW - Metallic materials KW - Experimental and numerical techniques KW - Mechanical properties KW - Plasticity PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578398 DO - https://doi.org/10.1146/annurev-matsci-080921-102621 SN - 1531-7331 VL - 53 SP - 275 EP - 317 AN - OPUS4-57839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Ning A1 - Hammerschmidt, Thomas A1 - Hickel, Tilmann A1 - Rogal, Jutta A1 - Drautz, Ralf T1 - Influence of spin fluctuations on structural phase transitions of iron N2 - The effect of spin fluctuations on the α(bcc)-γ(fcc)-δ(bcc) structural phase transitions in iron is investigated with a tight-binding (TB) model. The orthogonal d-valent TB model is combined with thermodynamic integration, spin-space averaging, and Hamiltonian Monte Carlo to compute the temperature-dependent free-energy difference between bcc and fcc iron. We demonstrate that the TB model captures experimentally observed phonon spectra of bcc iron at elevated temperatures. Our calculations show that spin fluctuations are crucial for both the α−γ and γ−δ phase transitions but they enter through different mechanisms. Spin fluctuations impact the α−γ phase transition mainly via the magnetic/electronic free-energy difference between bcc and fcc iron. The γ−δ phase transition, in contrast, is influenced by spin fluctuations only indirectly via the spin-lattice coupling. Combining the two mechanisms, we obtain both the α−γ and γ−δ phase transitions with our TB model. The calculated transition temperatures are in very good agreement with experimental values. KW - Structural phase transition KW - Magnetism KW - Spin-lattice coupling PY - 2023 DO - https://doi.org/10.1103/PhysRevB.107.104108 SN - 2469-9950 VL - 107 IS - 10 SP - 1 EP - 9 PB - American Physical Society (APS) AN - OPUS4-58790 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Janssen, Jan A1 - George, Janine A1 - Geiger, Julian A1 - Bercx, Marnik A1 - Wang, Xing A1 - Ertural, Christina A1 - Schaarschmidt, Joerg A1 - Ganose, Alex M. A1 - Pizzi, Giovanni A1 - Hickel, Tilmann A1 - Neugebauer, Joerg T1 - A Python workflow definition for computational materials design N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements the PWD in AiiDA, jobflow, and pyiron. KW - Automation KW - Workflows KW - Materials Design KW - Multi-scale simulation KW - Digitalization PY - 2025 DO - https://doi.org/10.5281/zenodo.15516179 PB - Zenodo CY - Geneva AN - OPUS4-63233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chen, Yu A1 - Bo, Zhen-Xing A1 - Zhou, Hong Bo A1 - Sun, Bao-An A1 - Sun, Yong Hao A1 - Maaß, Robert A1 - Wang, Wei Hua T1 - Nanoindentation reveals universal scaling of pop-in plasticity in metallic glasses N2 - Plastic flow of metallic glasses proceeds intermittently in the inhomogeneous deformation regime. Mediated via shear bands, quasi-static straining gives rise to plastic instabilities that are measured as abrupt displacement bursts or pop-ins. The latter is a well-known feature in nanoindentation, where its first occurrence probes the critical and site-specific stress of nano-scale incipient shear deformation. Here we show that the statistical distribution of the stress and magnitude of the first shear instability, as well as its successive higher-order events, universally follow Weibull statistics across ten different metallic glasses. This indicates a fundamentally identical plastic process across glass-forming alloys and progressing deformation that is governed by a weakest-link phenomenon. This finding stands in strong contrast to crystalline alloys, where both defect nucleation and defect-structure evolution control shear instabilities and depend on the deformation history. KW - Metallic glasses KW - Nanoindentation KW - Intermittent flow KW - Pop-ins KW - Weibull distribution PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624772 DO - https://doi.org/10.1016/j.scriptamat.2025.116549 VL - 259 SP - 1 EP - 5 PB - Elsevier Inc. AN - OPUS4-62477 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Zengquan A1 - Riechers, Birte A1 - Derlet, Peter M. A1 - Maaß, Robert T1 - Atomic cluster dynamics causes intermittent aging of metallic glasses N2 - In the past two decades, numerous relaxation or physical aging experiments of metallic glasses have revealed signatures of intermittent atomic-scale processes. Revealed via intensity cross-correlations from coherent scattering using X-ray photon correlation spectroscopy (XPCS), the observed abrupt changes in the time-domain of atomic motion does not fit the picture of gradual slowing down of relaxation times and their origin continues to remain unclear. Using a binary Lennard-Jones model glass subjected to microsecond-long isotherms, we show here that temporally and spatially heterogeneous atomic-cluster activity at different length-scales drive the emergence of highly non-monotonous intensity cross-correlations. The simulated XPCS experiments reveal a variety of time-dependent intensity-cross correlations that, depending on both the structural evolution and the 𝑞-space sampling, give detailed insights into the possible structural origins of intermittent aging measured with XPCS. KW - Metallic glasses KW - Aging KW - Molecular dynamics KW - XPCS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595415 DO - https://doi.org/10.1016/j.actamat.2024.119730 SN - 1359-6454 VL - 267 SP - 1 EP - 9 PB - Elsevier B.V. CY - Amsterdam, Niederlande AN - OPUS4-59541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, C. A1 - Tian, X. A1 - Wang, L. A1 - Liu, Y. A1 - Wirth, Cynthia A1 - Günster, Jens A1 - Li, D. A1 - Jin, Z. T1 - Effect of particle size gradation on the performance of glass-ceramic 3D printing process N2 - Particle size gradation is regarded as an effective method for overcoming the contradicting requirements in three-dimensional printing (3DP). In present work, particle size gradation was optimized to obtain both acceptable flowability of the powder material and high-strength 3D-printed glass-ceramic products. The effect of gradation on the printing process, sintering process and performance of the 3D-printed glass-ceramic products was investigated comprehensively. The glass-ceramic powders with three size ranges were mixed in certain proportions and applied to print parts. The result showed parts printed with powder mixed by 60 wt% 45–100 µm and 40 wt% 0–25 µm particles had satisfactory density of 1.60 g/cm³ and bending strength of 13.8 MPa. The flowability decreased with an increasing proportion of fine particles. Part density was determined by the powder bulk density in the powder bed as well as the shrinkage during sintering while strength of part was found to be dependent on the sintering degree. KW - Flowability KW - Glass-ceramic KW - Particle size gradation KW - Three-dimensional printing KW - Mechanical properties PY - 2017 DO - https://doi.org/10.1016/j.ceramint.2016.09.197 SN - 0272-8842 VL - 43 IS - 1 SP - 578 EP - 584 PB - Elsevier AN - OPUS4-39783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Lei A1 - Darvishi Kamachali, Reza T1 - Incorporating elasticity into CALPHAD-informed density-based grain boundary phase diagrams reveals segregation transition in Al-Cu and Al-Cu-Mg alloys N2 - The phase-like behavior of grain boundaries (GBs), recently evidenced in several materials, is opening up new possibilities in the design of alloy microstructures. In this context, GB phase diagrams are contributing to a predictive description of GB segregation and (interfacial) phase changes. The influence of chemo-mechanical solute-GB interactions on the GB phase diagram remains elusive so far. This is particularly important for multi-component alloys where the elastic interactions among solute atoms, of various sizes and bonding energies, can prevail, governing a complex co-segregation phenomenon. Recently, we developed a density-based model for GB thermodynamics that intrinsically accounts for GB elasticity in pure elements. In this work, we incorporate the homogeneous and heterogeneous elastic energies associated with the solutes into the density-based framework. We derive the multi-component homogeneous elastic energy by generalizing the continuum misfitting sphere model and extend it for GBs. The density-based free energy functional directly uses bulk CALPHAD thermodynamic data. The model is applied to binary and ternary Al alloys. We reveal that the elastic energy can profoundly affect the GB solubility and segregation behavior, leading to Cu segregation in otherwise Cu-depleted Al GBs. Consequently, GB segregation transition, i.e., a jump in the GB segregation as a function of alloy composition, is revealed in Al-Cu and Al-Cu-Mg alloy systems with implications for subsequent GB precipitation in these alloys. CALPHAD-informed elasticity-incorporated GB phase diagrams enable addressing a broader range of GB phenomena in engineering multi-component alloys. KW - Grain boundary thermodynamics KW - Density-based model KW - Al alloys KW - Grain boundary phase diagram KW - CALPHAD KW - Elastic energy PY - 2021 DO - https://doi.org/10.1016/j.commatsci.2021.110717 VL - 199 SP - 110717 PB - Elsevier B.V. AN - OPUS4-53058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ji, Y. A1 - Mezhov, Alexander A1 - Wang, S. A1 - Stephan, D. T1 - Influence of polycarboxylate superplasticizers with different molecular structures on rheological properties of glass bead suspension at different resting times N2 - Using an inert glass bead suspension, the study explores the interaction between various PCE superplasticizers, ions and investigates how it affects rheological performance during resting. To understand the underlying mechanisms, surface charge properties, adsorption, aggregates amount, and size of PCE during resting were measured. Results showed that yield stress increased with time, mainly when a high PCE dosage was used, and the modulus from strain sweep experiments agreed with the yield stress variations. The increase in zeta potential value and decrease in aggregate amount explain the decrease in yield stress in the non-PCE sample but are inconsistent with the increase in yield stress in presence of PCE. The PCE clusters’ size increases during resting, and increasing PCE adsorption does not disperse the glass bead particles. In addition, compared to the amount of carboxylate group, the molecular weight of PCE is more dominant in increasing the yield stress during resting. The increase in yield stress could be explained by the increase in the bridging and depletion forces due to the increasing size of the PCE cluster. Another possible reason is that non-adsorbed PCE clusters may form a polymer network that restricts the movement of the particles. KW - Glass bead KW - Rheological performance KW - PCE superplasticizers KW - Ion KW - Resting time PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617609 DO - https://doi.org/10.1016/j.colsurfa.2024.133583 SN - 0927-7757 VL - 688 IS - 133583 SP - 1 EP - 12 PB - Elsevier B.V. CY - Schweiz AN - OPUS4-61760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Lei A1 - Darvishi Kamachali, Reza T1 - CALPHAD integrated grain boundary co-segregation design: Towards safe high-entropy alloys N2 - Along with the desire for developing novel multi-principal element alloys, also known as high-entropy alloys, the concern about their safe application is also increasingly growing. This relates to the alloys’ phase stability, in particular, the control required over unexpected phase decompositions resulting from solute segregation at grain boundaries. Yet, the mechanisms of co-segregation and grain boundary phase decomposition in multi-component alloys are rather challenging to explore. In fact, quantitative investigation of grain boundary behaviors is mostly conducted for binary and a few ternary alloys. In this work, we apply the recently introduced CALPHAD-integrated density-based formalism [RSC Advances 10 (2020) 26728-26741] for considering co-segregation phenomena in alloys with an arbitrary number of components —the term ‘co-segregation’ here refers to co-evolution and any mutual interplay among the solute atoms during their interaction with a grain boundary. Quaternary Fe-Co-Mn-Cr alloy system is studied. We present two major advances beyond previous results: First, a co-segregation-induced multi-component grain boundary spinodal decomposition is quantitatively simulated for the first time. We found that in addition to its low cohesive energy and asymmetrical mixing enthalpy due to magnetic ordering, Mn plays a leading role in triggering interfacial phase decomposition by having a relatively large, concentration-dependent atomic mobility. Second, as an alternative to grain boundary phase diagrams proposed for binary and ternary alloys, we introduce the concept of co-segregation maps for grain boundary segregation screening and design in multi-component alloys. Applying the co-segregation maps, the nonlinear Mn and Cr co-segregation are discussed. Depicted on the alloying composition and phase space, the co-segregation maps enable the required insights to guide a safer, more controlled design of high-entropy alloys. KW - High-Entropy Materials KW - Density-based Phase-Field Modelling KW - CALPHAD KW - Alloys' Safety PY - 2023 DO - https://doi.org/10.1016/j.jallcom.2022.167717 SN - 0925-8388 VL - 933 SP - 1 EP - 12 PB - Elsevier CY - Lausanne AN - OPUS4-56274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Darvishi Kamachali, Reza A1 - Wang, L. T1 - Elastic energy of multi-component solid solutions and strain origins of phase stability in high-entropy alloys N2 - The elastic energy of mixing for multi-component solid solutions is derived by generalizing Eshelby's sphere-in-hole model. By surveying the dependence of the elastic energy on the chemical composition and lattice misfit, we derive a lattice strain coefficient λ*. Studying several high-entropy alloys and superalloys, we propose that most solid solution multi-component alloys are stable when λ*<0.16, generalizing the Hume-Rothery atomic-size rule for binary alloys. We also reveal that the polydispersity index δ, frequently used for describing strain in multi-component alloys, directly represents the elastic energy e with e=qδ², q being an elastic constant. Furthermore, the effects of (i) the number and (ii) the atomic-size distribution of constituting elements on the phase stability of high-entropy alloys were quantified. The present derivations and discussions open for richer considerations of elastic effects in high-entropy alloys, offering immediate support for quantitative assessments of their thermodynamic properties and studying related strengthening mechanisms. KW - Ordering KW - High-entropy alloys KW - Alloy design KW - Strain energy KW - Phase stability PY - 2022 DO - https://doi.org/10.1016/j.scriptamat.2021.114226 SN - 1359-6462 VL - 206 SP - 1 EP - 6 PB - Elsevier CY - Amsterdam AN - OPUS4-53427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Lei A1 - Darvishi Kamachali, Reza T1 - Density-based Thermodynamics of Microstructure Defects N2 - Systematic microstructure design requires reliable thermodynamic descriptions and phase diagrams of each and all microstructure elements. While such descriptions are well established for most bulk phases, thermodynamic assessment of crystal defects is greatly challenged by their individualistic aspects. In this talk, we present a density-based thermodynamic concept to describe defects based on available bulk thermodynamic data. Here dealing with grain boundaries (GBs), we apply this concept to compute GB (phase) diagram. Applications to segregation engineering of GBs in bulk and nanocrystalline alloys will be presented. We further develop this model to include the effect of elastic interactions due to atom size mismatch and obtain the corresponding GB (phase) diagram for the ternary Al-Cu-Li system. T2 - TMS 2021 CY - Online meeting DA - 15.03.2021 KW - Microstrucrue Design KW - Density-based Thermodynamics PY - 2021 AN - OPUS4-52337 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Janssen, Jan A1 - George, Janine A1 - Geiger, Julian A1 - Bercx, Marnik A1 - Wang, Xing A1 - Ertural, Christina A1 - Schaarschmidt, Joerg A1 - Ganose, Alex M. A1 - Pizzi, Giovanni A1 - Hickel, Tilmann A1 - Neugebauer, Joerg T1 - A Python workflow definition for computational materials design N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements the PWD in AiiDA, jobflow, and pyiron. KW - Automation KW - Workflow KW - Materials Design KW - Multi-scale simulation KW - Digitalization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632328 DO - https://doi.org/10.48550/arXiv.2505.20366 SP - 1 EP - 12 AN - OPUS4-63232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, X. A1 - Zhang, J. A1 - Wang, H. A1 - Rogal, J: A1 - Li, H.-Y. A1 - Wei, S.-H. A1 - Hickel, Tilmann T1 - Defect-characterized phase transition kinetics N2 - Phase transitions are a common phenomenon in condensed matter and act as a critical degree of freedom that can be employed to tailor the mechanical or electronic properties of materials. Understanding the fundamental mechanisms of the thermodynamics and kinetics of phase transitions is, thus, at the core of modern materials design. Conventionally, studies of phase transitions have, to a large extent, focused on pristine bulk phases. However, realistic materials exist in a complex form; their microstructures consist of different point and extended defects. The presence of defects impacts the thermodynamics and kinetics of phase transitions, but has been commonly ignored or treated separately. In recent years, with the significant advances in theoretical and experimental techniques, there has been an increasing research interest in modeling and characterizing how defects impact or even dictate phase transitions. The present review systematically discusses the recent progress in understanding the kinetics of defect-characterized phase transitions, derives the key mechanisms underlying these phase transitions, and envisions the remaining challenges and fruitful research directions. We hope that these discussions and insights will help to inspire future research and development in the field. KW - Kinetics KW - Atomistic models KW - Phase transitions KW - Defects PY - 2022 DO - https://doi.org/10.1063/5.0117234 SN - 1931-9401 VL - 9 IS - 4 SP - 1 EP - 42 PB - AIP CY - New York, NY AN - OPUS4-56507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Janssen, Jan A1 - George, Janine A1 - Geiger, Julian A1 - Bercx, Marnik A1 - Wang, Xing A1 - Ertural, Christina A1 - Schaarschmidt, Jörg A1 - Ganose, Alexander Miguel A1 - Pizzi, Giovanni A1 - Hickel, Tilmann A1 - Neugebauer, Jörg T1 - A Python workflow definition for computational materials design N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements the PWD in AiiDA, jobflow, and pyiron. KW - Worklows KW - FAIR Workflows KW - Automation KW - Materials Acceleration Platforms PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643325 DO - https://doi.org/10.1039/D5DD00231A SN - 2635-098X SP - 1 EP - 14 PB - Royal Society of Chemistry (RSC) AN - OPUS4-64332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pei, R. A1 - Petrazoller, J. A1 - Atila, Achraf A1 - Arnoldi, S. A1 - Xiao, L. A1 - Liu, X. A1 - Wang, H. A1 - Korte-Kerzel, S. A1 - Berbenni, S. A1 - Richeton, T. A1 - Guénolé, J. A1 - Xie, Z. A1 - Al-Samman, T. T1 - Solute co-segregation mechanisms at low-angle grain boundaries in magnesium: A combined atomic-scale experimental and modeling study N2 - Solute segregation at low-angle grain boundaries (LAGBs) critically affects the microstructure and mechanicalproperties of magnesium (Mg) alloys. In modern alloys containing multiple substitutional elements, understanding solute-solute interactions at microstructural defects becomes essential for alloy design. This study investigates the co-segregation mechanisms of calcium (Ca), zinc (Zn), and aluminum (Al) at a LAGB in a dilute Mg-0.23Al-1.00Zn-0.38Ca (AZX010) alloy by combining atomic-scale experimental and modeling techniques.Three-dimensional atom probe tomography (3D-APT) revealed significant segregation of Ca, Zn, and Al at the LAGB, with Ca forming linear segregation patterns along dislocation arrays characteristic of the LAGB. Clustering analysis showed increased Ca–Ca pairs at the boundary, indicating synergistic solute interactions. Atomistic simulations and elastic dipole calculations demonstrated that larger Ca atoms prefer tensile regions around dislocations, while smaller Zn and Al atoms favor compressive areas. These simulations also found that Ca–Ca co-segregation near dislocation cores is energetically more favorable than other solute pairings, explaining the enhanced Ca clustering observed experimentally. Thermodynamic modeling incorporating calculated segregation energies and solute-solute interactions accurately predicted solute concentrations at the LAGB, aligning with experimental data. The findings emphasize the importance of solute interactionsat dislocation cores in Mg alloys, offering insights for improving mechanical performance through targeted alloying and grain boundary engineering. KW - Atomic probe tomography KW - Atomistic simulation KW - Grain boundary KW - Co-segregation KW - Magnesium alloy PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655248 DO - https://doi.org/10.1016/j.actamat.2026.121947 SN - 1359-6454 VL - 306 SP - 1 EP - 13 PB - Elsevier Inc. AN - OPUS4-65524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Kun A1 - Schukar, Marcus A1 - Hicke, Konstantin A1 - Lu, Xin T1 - Effect of humidity on fiber-optic temperature sensing N2 - This study investigates the influence of ambient humidity on the temperature sensitivity, measurement accuracy, and uncertainty of optical fibers with different coatings, using a Rayleigh-based distributed sensing technique. Polymer-coated fibers (acrylate and polyimide) and metal-coated fibers (copper and gold) were tested under controlled humidity (30%–90% RH) and temperature (20–60 °C) conditions. Rayleigh-based measurements revealed a slight but consistent decrease in temperature sensitivity with increasing humidity for all polymer-coated fibers, attributed to humidity-induced changes in coating stiffness and strain transfer. In contrast, metal-coated fibers exhibited humidity-independent behavior and superior stability. These findings highlight the non-negligible role of ambient humidity in fiber-optic temperature sensing, particularly in Rayleigh-based systems using hygroscopic coatings. The results provide practical guidance for fiber and coating selection in humid environments and offer broader insight into humidity–strain–temperature coupling mechanisms relevant to other fiber-optic sensing mechanisms. KW - Distributed sensing KW - Humidity effect KW - Temperature sensing KW - Optical fiber coatings KW - Temperature uncertainty PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650040 DO - https://doi.org/10.1016/j.measurement.2025.119905 SN - 0263-2241 VL - 261 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-65004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Titirici, M. A1 - Baird, S. G. A1 - Sparks, T. D. A1 - Yang, S. M. A1 - Brandt-Talbot, A. A1 - Hosseinaei, O. A1 - Harper, D. P. A1 - Parker, R. M. A1 - Vignolini, S. A1 - Berglund, L. A. A1 - Li, Y. A1 - Gao, H.-L. A1 - Mao, L.-B. A1 - Yu, S.-H. A1 - Díez, N. A1 - Ferrero, G. A. A1 - Sevilla, M. A1 - Szilágyi, P. Á. A1 - Stubbs, C. J. A1 - Worch, J. C. A1 - Huang, Y. A1 - Luscombe, C. K. A1 - Lee, K.-Y. A1 - Luo, H. A1 - Platts, M. J. A1 - Tiwari, D. A1 - Kovalevskiy, D. A1 - Fermin, D. J. A1 - Au, H. A1 - Alptekin, H. A1 - Crespo-Ribadeneyra, M. A1 - Ting, V. P. A1 - Fellinger, Tim-Patrick A1 - Barrio, J. A1 - Westhead, O. A1 - Roy, C. A1 - Stephens, I. E. L. A1 - Nicolae, S. A. A1 - Sarma, S. C. A1 - Oates, R. P. A1 - Wang, C.-G. A1 - Li, Z. A1 - Loh, X. J. A1 - Myers, R. J. A1 - Heeren, N. A1 - Grégoire, A. A1 - Périssé, C. A1 - Zhao, X. A1 - Vodovotz, Y. A1 - Earley, B. A1 - Finnveden, G. A1 - Björklund, A. A1 - Harper, G. D. J. A1 - Walton, A. A1 - Anderson, P. A. T1 - The sustainable materials roadmap N2 - Our ability to produce and transform engineered materials over the past 150 years is responsible for our high standards of living today, especially in the developed economies. Yet, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of economy, energy, and climate. We are at the point where something must drastically change, and it must change NOW. We must create more sustainable materials alternatives using natural raw materials and inspiration from Nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments based on reliable and relevant data to quantify sustainability. KW - Electrochemistry KW - Fe-N-C catalysts KW - Fuel cells KW - Catalysis PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550126 DO - https://doi.org/10.1088/2515-7639/ac4ee5 SN - 2515-7639 VL - 5 IS - 3 SP - 1 EP - 98 PB - IOP Publishing CY - Bristol AN - OPUS4-55012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogel, Christian A1 - Helfenstein, J. A1 - Massey, M. A1 - Sekine, R. A1 - Kretzschmar, R. A1 - Beiping, L. A1 - Peter, T. A1 - Chadwick, O. A1 - Tamburini, F. A1 - Rivard, C. A1 - Herzel, Hannes A1 - Adam, Christian A1 - Pradas del Real, A. A1 - Castillo-Michel, H. A1 - Zuin, L. A1 - Wang, D. A1 - Félix, R. A1 - Lassalle-Kaiser, B. A1 - Frossard, E. T1 - Microspectroscopy reveals dust-derived apatite grains in acidic, highly-weathered Hawaiian soils N2 - Dust deposition is an important source of phosphorus (P) to many ecosystems. However, there is little evidence of dust-derived P-containing minerals in soils. Here we studied P forms along a well-described climatic Gradient on Hawaii, which is also a dust deposition gradient. Soil mineralogy and soil P forms from six sites along the climatic gradient were analyzed with bulk (X-ray diffraction and P K-edge X-ray absorption near edge structure) and microscale (X-ray fluorescence, P K-edge X-ray absorption near edge structure, and Raman) analysis methods. In the wettest soils, apatite grains ranging from 5 to 30 μm in size were co-located at the micro-scale with quartz, a known continental dust indicator suggesting recent atmospheric deposition. In addition to co-location with quartz, further evidence of dust-derived P included backward trajectory modeling indicating that dust particles could be brought to Hawaii from the major global dust-loading areas in central Asia and northern Africa. Although it is not certain whether the individual observed apatite grains were derived from long-distance transport of dust, or from local dust sources such as volcanic ash or windblown fertilizer, these observations offer direct evidence that P-containing minerals have reached surface layers of highly-weathered grassland soils through atmospheric deposition. KW - Phosphorus KW - soil KW - microspectroscopy KW - Raman spectroscopy KW - XANES spectroscopy KW - x-ray diffraction PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511522 DO - https://doi.org/10.1016/j.geoderma.2020.114681 SN - 0166-0918 SN - 1872-6259 VL - 381 SP - 114681-1 EP - 114681-11 PB - Elsevier CY - Amsterdam AN - OPUS4-51152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Günster, Jens A1 - Wang, Gong A1 - Tian, Xiaoyong T1 - 3D Printing Technologies for Extreme Environment in Space N2 - 3D printing technology can realize the rapid fabrication of complicated structures with short production chain, which just meet the requirements for space manufacturing in the future. However, 3D printing technologies in space are still challenging due to the harsh conditions, such as microgravity, high vacuum, and large temperature difference. Meanwhile, in-situ resource utilization and recycling must be considered as a cost effective and resilient resource for 3D printing in space. On the contrary, extreme environmental conditions such as high vacuum and microgravity can also offer significant advantages for advanced materials with high purity and performance. In-situ fabrication of ultra-large components would overcome the weight and structural limitations imposed by rocket launch and change the future strategy for space exploration. The aim of this specially issue is therefore to provide a platform for discussing the potential technologies for 3D printing in space. KW - Additive Manufacturing KW - space PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652654 DO - https://doi.org/10.1016/j.amf.2025.200248 SN - 2950-4317 VL - 4 IS - 3 SP - 1 EP - 2 PB - Elsevier AN - OPUS4-65265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogel, Christian A1 - Sekine, R. A1 - Steckenmesser, D. A1 - Lombi, E. A1 - Herzel, Hannes A1 - Zuin, L. A1 - Wang, D. A1 - Felix, R. A1 - Adam, Christian T1 - Combining diffusive gradients in thin films (DGT) and spectroscopic techniques for the determination of phosphorus species in soils N2 - A wide range of methods are used to estimate the plant-availability of soil phosphorus (P). Published research has shown that the diffusive gradients in thin films (DGT) technique has a superior correlation to plant-available P in soils compared to standard chemical extraction tests. In order to identify the plantavailable soil P species, we combined DGT with infrared and P K- and L2,3-edge X-ray adsorption near edge structure (XANES) spectroscopy. This was achieved by spectroscopically investigating the dried binding layer of DGT devices after soil deployment. All three spectroscopic methods were able to distinguish between different kinds of phosphates (poly-, trimeta-, pyro- and orthophosphate) on the DGT binding layer. However, infrared spectroscopy was most sensitive to distinguish between different types of adsorbed inorganic and organic phosphates. Furthermore, intermediates of the time-resolved hydrolysis of trimetaphosphate in soil could be analyzed. KW - Phosphorus plant-availability KW - X-ray adsorption near-edge structure (XANES) spectroscopy KW - Infrared spectroscopy KW - Diffusive gradients in thin films (DGT) PY - 2019 DO - https://doi.org/10.1016/j.aca.2019.01.037 SN - 0003-2670 VL - 1057 SP - 80 EP - 87 PB - Elsevier AN - OPUS4-47471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Cui T1 - Ratiometric Nanosensors for Simultaneously “TOP” Measuring Temperature, Oxygen and pH at a Single Excitation Wavelength N2 - In summary, by combining the NIR-emissive [Cr(ddpd)2][BPh4]3 complex CrBPh4 with its extremely large energy gap between the longest wavelength absorption and emission maxima with a pH-responsive fluorescein derivative (FITC) and an inert reference dye like Nile Red (NR) and 5,10,15,20tetrakis(pentafluorophenyl) porphyrin (TFPP), we developed nanosensors for simultaneously sensing temperature, O2 partial pressure, and pH. These novel TOP nanosensors (temperature, oxygen, pH) cover the biologically and physiologically relevant concentration ranges of these parameters/analytes with single wavelength excitation in PBS buffer and in a cell culture medium containing bovine serum albumin (BSA). The response of both nanosensors to all parameters is fully reversible and only minimally affected by the presence of BSA, the most common serum albumin. Moreover, comparative studies with nanosensors containing only a single type of stimuli-responsive molecule and with the respective molecular systems revealed that the different sensor components do not interfere with each other. Future research will include the testing of these nanosensors in cellular uptake studies and, after surface modification with targeted bioligands, eventually in in vivo experiments as previously done by some of us with other polystyrene nanoparticle reporters and nanosensors.46,47 Moreover, this concept of multianalyte sensing will be expanded to nanosensors derived from differently sized premanufactured biocompatible polymer particles and different stimuli-responsive dyes like fluorescent indicators for biologically and bioanalytically relevant metal ions. T2 - ISPPCC 2019 CY - Hong Kong, China DA - 14.07.2019 KW - Medical diagnostics KW - Sensor KW - Nnanoparticle KW - Nanosensor KW - Fluorescence KW - Oxygen KW - Temperature KW - Ratiometric KW - PH KW - Lifetime KW - NIR KW - Cr(III) complex KW - FITC KW - Dye KW - Environment PY - 2019 AN - OPUS4-49698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Li, Z. A1 - Wang, D.-Y. A1 - Schoenhals, Andreas T1 - Dielectric and flash DSC investigations on an epoxy based nanocomposite system with MgAl layered double hydroxide as nanofiller N2 - Nanocomposites based on MgAL layered double hydroxides (LDH) and an epoxy resin were prepared and investigated by a combination of complementary methods. As epoxy resin Bisphenol A diglycidyl ether (DGEBA) was used with Diethylenetriamine as curing agent. The LDH was modified with taurine, which acts as an additional crosslinking agent due to its amine groups. The epoxy resin was cured in a presence of the nanofiller, which was added to the system in various concentrations. X-ray scattering, by combination of SAXS and WAXS was used to characterize the morphology of the obtained nanocomposites. These investigations show that the filler is distributed in the matrix as small stacks of ca. 10 layers. The molecular dynamics of the system, as probe for structure, was investigated by broadband dielectric spectroscopy. In addition to the - and -relaxation (dynamic glass transition), characteristic for the unfilled materials, a further process was found which was assigned to localized fluctuations of segments physically adsorbed or chemically bonded to the nanoparticles. The dielectric -relaxation is shifted to higher temperatures for the nanocomposites in comparison to the pure material but depends weakly on the content of nanoparticles. Further, for the first time Flash DSC was employed to a thermosetting system to investigate the glass transition behavior of the nanocomposites. The heating rates were converted in to relaxation rates. For low concentrations of the nanofiller the thermal data overlap more or less with that of the pure epoxy. For higher concentrations the thermal data are shifted significantly to higher temperatures. This is discussed in terms the cooperativity approach to the glass transition. KW - Nanocomposites KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2019 DO - https://doi.org/10.1016/j.tca.2019.01.010 SN - 0040-6031 VL - 677 SP - 151 EP - 161 PB - Elsevier AN - OPUS4-48218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Bin T1 - Determination of Distribution Function used in MCS on Safety Analysis of Hydrogen Pressure Vessel N2 - The test data of static burst strength and load cycle strength of composite pressure vessels are often described by GAUSSian normal or WEIBULL distribution function to perform safety analyses. The goodness of assumed distribution function plays a significant role in the inferential statistics to predict the population properties by using limited test data. Often, GAUSSian and WEIBULL probability nets are empirical methods used to validate the distribution function; Anderson-Darling and KolmogorovSmirnov tests are the mostly favorable approaches for Goodness of Fit. However, the different approaches used to determine the parameters of distribution function lead mostly to different conclusions for safety assessments. In this study, six different methods are investigated to show the variations on the rates for accepting the composite pressure vessels according to GTR No. 13 life test procedure. The six methods are: a) NormLog based method, b) Least squares regression, c) Weighted least squares regression, d) A linear approach based on good linear unbiased estimators, e) Maximum likelihood estimation and f) The method of moments estimation. In addition, various approaches of ranking function are considered. In the study, Monte Carlo simulations are conducted to generate basic populations based on the distribution functions which are determined using different methods. Then the samples are extracted randomly from a population and evaluated to obtain acceptance rate. Here, the “populations” and “samples” are corresponding to the burst strength or load cycle strength of the pressure vessels made from composite material and a plastic liner (type 4) for the storage of hydrogen. To the end, the results are discussed, and the best reliable methods are proposed. T2 - ICHS2019 Conference CY - Adelaide, Australia DA - 24.09.2019 KW - Monte-Carlo Simulation KW - Distribution function KW - Weibull Distribution PY - 2019 AN - OPUS4-49652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Saul, Herbert A1 - Wang, Bin T1 - Safety criteria for the transport of hydrogen in permanently mounted composite pressure vessels N2 - The recent growing of the net of hydrogen fuelling stations increases the demands to transport compressed hydrogen on road by tube-trailers in composite pressure vessels. As transport regulation the ADR is applicable in Europe and adjoined regions and used for national transport in EU. This regulation provides requirements based on the burst pressure of each individual pressure vessel, regardless the capabilities of the transported hydrogen and relevant consequences resulting from worst case scenarios. In 2012, BAM (German Federal Institute for Materials Research and Testing) introduced consequence-dependent requirements and established them in national requirements concerning the “UN service life checks” etc.) to consider the transported volume and pressure of gases. However, this results in a stringent requirement in case of using large pressure vessels (tubes) on tube-trailers. In the studies presented here, the key safety factors for using hydrogen trailers are identified and reviewed through some safety measures from some countries like Japan, USA and China. Subsequently, the risk, chance, failure consequences of using trailers are evaluated, in addition, the difficulties for approving huge pressure vessels (large tubes) are addressed. There, a maximum acceptable pressure-volume product is defined. Finally, a performance-based criterion for the balance of chance and risk of hydrogen trailers is suggested to add into regulations and consequently into standards for hydrogen trailers. T2 - ICHS (International Conference on Hydrogen Safety) 2019 CY - Adelaide, Australia DA - 24.09.2019 KW - Battery vehicle KW - Pressure-volume product KW - Maximum acceptable consequence KW - Catastrophe KW - F-N-curve KW - Pressure wave PY - 2019 AN - OPUS4-50088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ren, J. A1 - Weigert, Florian A1 - Weber, F. A1 - Wang, Y. A1 - Choudhury, S. A1 - Xiao, J. A1 - Lauermann, I. A1 - Resch-Genger, Ute A1 - Bande, A. A1 - Petit, T. ED - Petit, Tristan T1 - Influence of surface chemistry on optical, chemical and electronic properties of blue luminescent carbon dots N2 - Carbon dots have attracted much attention due to their unique optical, chemical and electronic properties enabling a wide range of applications. The properties of carbon dots can be effectively adjusted through modifying their chemical composition. However, a major challenge remains in understanding the core and surface contributions to optical and electronic transitions. Here, three blue luminescent carbon dots with carboxyl, amino and hydroxyl groups were comprehensively characterized by UV-vis absorption and emission spectroscopy, synchrotron-based X-ray spectroscopy, and infrared spectroscopy. The influence of the surface functionality on their fluorescence was probed by pH-dependent photoluminescence measurements. Moreover, the hydrogen bonding interactions between water and the surface groups of carbon dots were characterized by infrared spectroscopy. Our results show that both core and surface electronic states of blue luminescent carbon dots contribute to electronic acceptor levels while the chemical nature of the surface groups determines the hydrogen bonding behavior of the carbon dots. This comprehensive spectroscopic study demonstrates that the surface chemistry has a profound influence on the electronic configuration and surface–water interaction of carbon dots, thus affecting their photoluminescence properties. KW - Quantum dots KW - Spectroscopy KW - UV Vis KW - Fluorescence KW - Surface chemistry PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472325 DO - https://doi.org/10.1039/c8nr08595a SN - 2040-3372 VL - 11 IS - 4 SP - 2056 EP - 2064 PB - RSC AN - OPUS4-47232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gharaati, S. A1 - Wang, Cui A1 - Förster, C. A1 - Weigert, Florian A1 - Resch-Genger, Ute A1 - Heinze, K. T1 - Triplet–Triplet Annihilation Upconversion in a MOF with AcceptorFilled Channels N2 - In summary, we report a highly modular solid TTA-UC system comprising of a crystalline, thermally stable PCN222(Pd) MOF with CA-coated MOF channels and with a DPA annihilator embedded in a solution-like environment in the MOF channels. This solid material displays blue upconverted delayed emission with a luminescence lifetime of 373 us, a threshold value of 329 mW*cm-2 and a triplet–triplet energy transfer efficiency of 82%. This optical application adds another facet to the versatile chemistry of PCN-222 MOFs. The design concept is also applicable to other TTA-UC pairs and enables tuning of the UCL color, for example, by replacing DPA with other dyes as exemplarily shown for 2,5,8,11-tetra-tert-butyl-perylene, that yields UCL at 450 nm. Current work aims to reduce the oxygen sensitivity and to increase the retention of the trapped annihilators in organic environments, for example, by tuning the chain length of the carboxylic acid and by coating the MOF surface. In addition, the TTA-UC efficiency will be further enhanced by reducing the reabsorption of the UC emission caused by Pd(TCPP) and by optimizing the sensitizer/annihilator interface. KW - Porphyrin KW - Method KW - MOF KW - Fluorescence KW - Dye KW - Sensor KW - Oxygen sensitive KW - Single molecule KW - DPA KW - Lifetime KW - Upconverstion KW - Quantum yield KW - Triplet-triplet annihilation KW - Sensitization KW - Energy transfer KW - NMR PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500580 DO - https://doi.org/10.1002/chem.201904945 VL - 26 IS - 5 SP - 1003 EP - 1007 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-50058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Biegler, M. A1 - Wang, J. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Automated tool-path generation for rapid manufacturing and numerical simulation of additive manufacturing LMD geometries N2 - In additive manufacturing (AM) Laser Metal Deposition (LMD), parts are built by welding layers of powder feedstock onto a substrate. Applications for steel powders include forging tools and structural components for various industries. For large parts, the choice of tool-paths influences the build-rate, the part performance and the distortions in a highly geometry-dependent manner. With weld-path lengths in the range of hundreds of meters, a reliable, automated tool path generation is essential for the usability of LMD processes. In this contribution, automated tool-path generation approaches are shown and their results are discussed for arbitrary geometries. The investigated path strategies are the classical approaches: “Zig-zag-” and “contour-parallel-strategies”. After generation, the tool-paths are automatically formatted into g-code for experimental build-up and ASCII for a numerical simulation model. Finally, the tool paths are discussed in regards to volume-fill, microstructure and porosity for the experimental samples. This work presents a part of the IGF project 18737N “Welding distortion simulation” (FOSTA P1140) T2 - 4th European Steel Technology and Application Days CY - Dusseldorf, Germany DA - 24.06.2019 KW - Additive manufacturing KW - Directed Energy Deposition KW - Path planning KW - DED KW - Mechanical properties KW - Porosity PY - 2019 SP - 1 AN - OPUS4-50045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Czuban, M. A1 - Kulka, M. W. A1 - Wang, L. A1 - Koliszak, A. A1 - Achazi, K. A1 - Schlaich, C. A1 - Donskyi, Ievgen A1 - Di Luca, M. A1 - Mejia Oneto, J. M. A1 - Royzen, M. A1 - Haag, R. A1 - Trampuz, A. T1 - Titanium coating with mussel inspired polymer and bio-orthogonal chemistry enhances antimicrobial activity against Staphylococcus aureus N2 - Implant-associated infections present severe and difficult-to-treat complications after surgery, related to implant biofilm colonization. Systemic administration of antibiotics cannot reach sufficient concentrations at the infected site and may be toxic. Here we describe how mussel-inspired dendritic material coated on a titanium surface can locally activate a prodrug of daptomycin (pro-dapto) to treat methicillin-resistant Staphylococcus aureus. The mechanism of the prodrug activation is based on bio-orthogonal click chemistry between a tetrazine (Tz) and trans-cyclooctene (TCO). The former is attached to the dendritic polymer, while the later converts daptomycin into a prodrug. Characterization of the material's properties revealed that it is hydrophobic, non-toxic, and stable for a prolonged period of time. We envision that the titanium coated dendritic material will be able to improve the treatment of implant-associated infections by concentrating systemically administered antibiotic prodrugs, thus converting them into active localized medicines. KW - Bio-orthogonal chemistry KW - Antimicrobial titanium coating KW - Prodrug antibiotic KW - Antibiotic delivery KW - Antibiotic release KW - XPS PY - 2020 DO - https://doi.org/10.1016/j.msec.2020.111109 VL - 116 SP - 111109 PB - Elsevier B.V. AN - OPUS4-51204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Darvishi Kamachali, Reza A1 - Wang, Lei A1 - Lin, L. L. A1 - Manzoni, Anna Maria A1 - Skrotzki, Birgit A1 - Thompson, G. B. T1 - CALPHAD-informed density-based grain boundary thermodynamics N2 - The Gibbs free energy of a grain boundary is a complex thermodynamic function of temperature, pressure, and composition. These complexities add to the intrinsic crystallographic and chemical constraints imposed by the adjacent bulk phase. Recently we have proposed a density-based model for assessing grain boundary thermodynamics that enables a CALPHAD-informed description of the grain boundary. As such, the Gibbs free energy of the grain boundary is directly linked with available CALPHAD thermodynamic data. In this talk, new aspects of interfacial segregation and phase transformation are revealed by benchmarking the current model for various experimental cases, including several steels, high-entropy alloys and aluminum alloys. The effects of elastic interactions on the grain boundary segregation and the application of the model to a nanocrystalline Pt-Au alloy, with numerous grain boundaries of various characters, will be discussed. T2 - DPG (Deutsche Physiker Gesellschaft) CY - Online meeting DA - 27.09.2021 KW - Density-based model KW - Defects thermodynamics KW - Defects phase diagram KW - CALPHAD KW - Crystal Defects PY - 2021 AN - OPUS4-53556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogl, Jochen A1 - Yim, Y.-H. A1 - Lee, K.-S. A1 - Goenaga-Infante, H A1 - Malinovskiy, D. A1 - Hill, S. A1 - Ren, T. A1 - Wang, J. A1 - Vocke, R. D. A1 - Murphy, K. E. A1 - Nonose, N. A1 - Rienitz, O. A1 - Noordmann, J. T1 - Certification of ERM-EB400, the first matrix reference material for lead isotope amount ratios, and ERM-AE142, a lead solution providing a lead isotopic composition at the edge of natural variation N2 - Lead isotope amount ratios are commonly used in diverse fields such as archaeometry, geochemistry and forensic science. Currently, five reference materials with certified lead isotope amount ratios are available, namely NIST SRM 981, 982 and 983, GBW-04442 and NMIJ 3681-a. Only NIST SRM 981 and NMIJ 3681-a have approximately natural isotopic compositions, and NIST SRM 981 is predominantly used for correcting mass discrimination/mass fractionation in the applied mass spectrometric procedures. Consequently, there is no other certified reference material available to be used for validation and/or quality control of the analytical procedures applied to lead isotope amount ratio measurements. To fill this gap, two new reference materials have been produced and certified for their lead isotope amount ratios. For both certified reference materials, complete uncertainty budgets have been calculated and SI traceability has been established. This provides the users with independent means for validating and verifying their analytical procedures and for conducting quality control measures. ERM-EB400 is a bronze material with a nominal lead mass fraction of 45 mg kg-1 and certified lead isotope amount ratios of n(206Pb)/n(204Pb) = 18.072(17) mol mol-1, n(207Pb)/n(204Pb) = 15.578(18) mol mol-1 and n(208Pb)/n(204Pb) = 38.075(46) mol mol-1 with the associated expanded uncertainties (k = 2) given in brackets. ERM-AE142 is a high-purity solution of lead in 2% nitric acid with a nominal mass fraction of 100 mg kg-1 and certified Pb isotope amount ratios of n(206Pb)/n(204Pb) = 21.114(17) mol mol-1, n(207Pb)/n(204Pb) = 15.944(17) mol mol-1 and n(208Pb)/n(204Pb) = 39.850(44) mol mol-1 with the associated expanded uncertainties (k = 2) given in brackets. Both materials are specifically designed to fall within the natural lead isotopic variation and to assist users with the validation and verification of their analytical procedures. Note that while one of these reference materials requires the chemical separation of Pb from its matrix (ERM-EB400), the other does not (ERM-AE142). As additional information, δ208/206PbNIST SRM981 values are provided for both materials. For ERM-AE142, a delta value of δ208/206PbNIST SRM981 = -28.21(30) ‰ was obtained, and for ERM-EB400, a delta value of δ208/206PbNIST SRM981 = -129.47(38) ‰ was obtained, with the associated expanded uncertainties (k = 2) given in brackets. KW - Lead isotope variations KW - Radiogenic isotopes KW - Isotope reference material KW - Metrology in chemistry KW - Measurement uncertainty PY - 2019 DO - https://doi.org/10.1111/ggr.12253 SN - 1751-908X SN - 1639-4488 VL - 43 IS - 1 SP - 23 EP - 37 PB - John Wiley & Sons AN - OPUS4-47383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Treiling, S. A1 - Wang, Cui A1 - Förster, C. A1 - Reichenauer, F. A1 - Kalmbach, J. A1 - Boden, P. A1 - Harris, J. P. A1 - Carrella, L. M. A1 - Rentschler, E. A1 - Resch-Genger, Ute A1 - Reber, C. A1 - Seitz, M. A1 - Gerhards, M. A1 - Heinze, K. T1 - Luminescence and Light-Driven Energy and Electron Transfer from an Exceptionally Long-Lived Excited State of a Non-Innocent Chromium(III) Complex N2 - Photoactive metal complexes employing Earth‐abundant metal ions are a key to sustainable photophysical and photochemical applications. We exploit the effects of an inversion center and ligand non‐innocence to tune the luminescence and photochemistry of the excited state of the [CrN6] chromophore [Cr(tpe)2]3+ with close to octahedral symmetry (tpe=1,1,1‐tris(pyrid‐2‐yl)ethane). [Cr(tpe)2]3+ exhibits the longest luminescence lifetime (τ=4500 μs) reported up to date for a molecular polypyridyl chromium(III) complex together with a very high luminescence quantum yield of Φ=8.2 % at room temperature in fluid solution. Furthermore, the tpe ligands in [Cr(tpe)2]3+ are redox non‐innocent, leading to reversible reductive chemistry. The excited state redox potential and lifetime of [Cr(tpe)2]3+ surpass those of the classical photosensitizer [Ru(bpy)3]2+ (bpy=2,2′‐bipyridine) enabling energy transfer (to oxygen) and photoredox processes (with azulene and tri(n‐butyl)amine). KW - Quantum yield KW - Cr(III) complex KW - Longst luminescence lifetime KW - Electron transfer PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494870 DO - https://doi.org/10.1002/anie.201909325 VL - 58 SP - 2 EP - 13 PB - Wiley-VCH AN - OPUS4-49487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frübing, P. A1 - Wang, F. A1 - Günter, C. A1 - Gerhard, R. A1 - Wegener, M. A1 - Jaunich, Matthias A1 - Stark, Wolfgang T1 - Relation between dielectric and mechanical losses in ferroelectric poly(vinylidene fluoride - hexafluoropropylene) films N2 - The temperature dependences of dielectric permittivity and elastic modulus of poly(vinylidene fluoride - hexafluoropropylene) (P(VDF-HFP)) are compared and explained by use of structural data obtained by differential scanning calorimetry and X-ray analysis. Special emphasis is put on the effect of uniaxial stretching which renders the polymer ferroelectric. It is shown that dielectric and mechanical relaxations at the glass transition (aa relaxation) are closely related and not significantly affected by stretching. It is further confirmed that stretching destroys the non-polar spherulitic crystalline structure and produces relatively small-sized polar crystallites. This manifests in the disappearence of the so-called ac relaxation which is associated to molecular motions within the spherulitic crystalline lamellae. However, there are discrepancies between dielectric and mechanical losses above the glass transition which point towards a still not described structural transition. T2 - 10th IEEE International conference on solid dielectrics (ICSD) CY - Potsdam, Germany DA - 2010-07-04 KW - Poly(vinylidene(fluoride - hexafluoropropylene) KW - P(VDF-HFP) KW - Ferroelectric polymer KW - Dielectric relaxation KW - Dynamic mechanical analysis KW - Uniaxial stretching PY - 2010 SN - 978-1-4244-7945-0 DO - https://doi.org/10.1109/ICSD.2010.5567936 SP - 1 EP - 4(?) AN - OPUS4-23421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abraham, O. A1 - Niederleithinger, Ernst A1 - Chapeleau, X. A1 - Klikowicz, P. A1 - Brühwiler, E. A1 - Bassil, A. A1 - Wang, Xin A1 - Chakraborty, J. A1 - Bayane, I. A1 - Leduc, D. A1 - Salamak, M. A1 - Katunin, A. A1 - Sørensen, J.D. T1 - Addressing the need to monitor concrete fatigue with nondestructive testing: Results of infrastar European project N2 - Fatigue is one of the most prevalent issues, which directly influences the service life expectancy of concrete structures. Fatigue has been investigated for years for steel structures. However, recent findings suggest that concrete structures may also be significantly subjected to fatigue phenomena that could lead to premature failure of certain structural elements. To date, fatigue of reinforced concrete has been given little focus. Knowledge on the influence factors and durability/capacity effects on this material should be improved. Current technological means to measure fatigue in civil structures like bridges and wind turbines (both onshore and offshore) are outdated, imprecise and inappropriate. Meanwhile, this topic has got much more attention as time-variant loading on concrete structures plays an increasing role, e.g. in bridges with increasing traffic and heavier trucks, and for wind turbines for renewable energy production, e.g. for offshore wind turbine support structures affected by wind and waves. The European Innovative Training Networks (ITN) Marie Skłodowska-Curie Actions project INFRASTAR (Innovation and Networking for Fatigue and Reliability Analysis of Structures - Training for Assessment of Risk) provides research training for 12 PhD students. The project aims to improve knowledge for optimizing the design of new structures as well as for more realistic verification of structural safety and more accurate prediction of the remaining fatigue lifetime of existing concrete structures. First, the INFRASTAR research framework is detailed. Then it will be exemplified through the presentation of the major results of the four PhD students involved in the work package dealing with auscultation and monitoring. This includes the development and improvement of Fiber Optics (FO) and Coda Wave Interferometry (CWI) for crack sizing and imagery, new sensor technologies and integration, information management, monitoring strategy for fatigue damage investigation and lifetime prediction. T2 - SMT and NDT-CE 2018 CY - New Brunswick, NJ, USA DA - 27.08.2018 KW - Concrete KW - Fatigue KW - Crack KW - Monitoring KW - Non-destructive testing PY - 2019 UR - https://asnt.org/smt18papers SN - 978-1-57117-456-7 VL - 11/19 SP - 2 EP - 13 PB - The American Society for Nondestructive Testing, Inc. CY - Columbus, OH, USA AN - OPUS4-47237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duffner, Eric A1 - Wang, Bin A1 - Kriegsmann, Andreas T1 - WP8 RCS standardisation work, Probabilistic safety assessment & statistic N2 - Achievements within WP8 in the TAHYA Project during the first 18 month, including ongoing work and next steps. Including safety definition, introduction to probabilistic Approach, failure rate, consequence and risk Definition, introduction monte-carlo-Simulation. T2 - TAHYA Midterm review meeting CY - Brüssel, Belgium DA - 26.09.2019 KW - TAHYA project PY - 2019 AN - OPUS4-49191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Saul, Herbert A1 - Wang, Bin T1 - Safety criteria for the transport of hydrogen in permanently mounted composite pressure vessels N2 - The recent growing of the net of hydrogen fuelling stations increases the demands to transport compressed hydrogen on road by batterie vehicles or tube-trailers, both in composite pressure vessels. As transport regulation the ADR is applicable in Europe and adjoined regions and used for national transport in EU. This regulation provides requirements based on the burst pressure of each individual pressure vessel, regardless the capabilities of the transported hydrogen and relevant consequences resulting from worst case scenarios. In 2012, BAM (German Federal Institute for Materials Research and Testing) introduced consequence-dependent requirements and established them in national requirements concerning the “UN service life checks” etc. to consider the transported volume and pressure of gases. However, this results in a stringent requirement in case of using large pressure vessels (so called “tubes”) on vehicles. In the studies presented here, the safety measures for hydrogen road transport are identified and reviewed through some safety measures from some countries like Japan, USA and China. Subsequently, the failure consequences of using trailers, the related risks and chances are evaluated. Finally, a chance-related risk criterion is suggested to add into regulations and consequently to be defined as safety goal in standards for hydrogen transport vehicles and consequently for mounted pressure vessels. T2 - ICHS International Conference on Hydrogen Safety) 2019 CY - Adelaide, Australia DA - 24.09.2019 KW - pressure-volume product KW - probabilistic approach KW - hydrogen transport KW - risk limit KW - F-N-diagram KW - maximum acceptable consequence KW - chance-risk analysis KW - specific risk value PY - 2019 SP - 104-01 EP - 104-15 PB - International Association for Hydrogen Safety (HySafe) CY - Adelaide AN - OPUS4-50124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Bin A1 - Mair, Georg W. A1 - Gesell, Stephan T1 - Determination of Distribution Function used in MCS on Safety Analysis of Hydrogen Pressure Vessel N2 - The test data of static burst strength and load cycle strength of composite pressure vessels are often described by GAUSSian normal or WEIBULL distribution function to perform safety analyses. The goodness of assumed distribution function plays a significant role in the inferential statistics to predict the population properties by using limited test data. Often, GAUSSian and WEIBULL probability nets are empirical methods used to validate the distribution function; Anderson-Darling and Kolmogorov-Smirnov tests are the mostly favorable approaches for Goodness of Fit. However, the different approaches used to determine the parameters of distribution function lead mostly to different conclusions for safety assessments. In this study, six different methods are investigated to show the variations on the rates for accepting the composite pressure vessels according to GTR No. 13 life test procedure. The six methods are: a) Norm-Log based method, b) Least squares regression, c) Weighted least squares regression, d) A linear approach based on good linear unbiased estimators, e) Maximum likelihood estimation and f) The method of moments estimation. In addition, various approaches of ranking function are considered. In the study, Monte Carlo simulations are conducted to generate basic populations based on the distribution functions which are determined using different methods. Then the samples are extracted randomly from a population and evaluated to obtain acceptance rate. Here, the “populations” and “samples” are corresponding to the burst strength or load cycle strength of the pressure vessels made from composite material and a plastic liner (type 4) for the storage of hydrogen. To the end, the results are discussed, and the best reliable methods are proposed. T2 - ICHS International Conference on Hydrogen Safety) 2019 CY - Adelaide, Australia DA - 24.09.2019 KW - Monte-Carlo Simulation KW - Distribution function KW - Weibull Distribution PY - 2019 SP - 103-1 EP - 103-16 AN - OPUS4-50383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Cui A1 - Otto, S. A1 - Dorn, M. A1 - Heinze, K. A1 - Resch-Genger, Ute T1 - Luminescent TOP nanosensors for simultaneously measuring temperature, oxygen, and pH at a single excitation wavelength N2 - Two nanosensors for simultaneous optical measurements of the bioanalytically and biologically relevant analytes temperature (“T”), oxygen (“O”), and pH (“P”) have been designed. These “TOP” nanosensors are based on 100 nmsized silica-coated polystyrene nanoparticles (PS-NPs) doped with a near-infrared emissive oxygen- and temperature-sensitive chromium(III) complex ([Cr(ddpd)2][BPh4]3, CrBPh4) and an inert reference dye (Nile Red, NR or 5,10,15,20tetrakis(pentafluorophenyl) porphyrin, TFPP) and are covalently labeled with pHsensitive fluorescein isothiocyanate (FITC). These emitters can be excited at the same wavelength and reveal spectrally distinguishable emission bands, allowing for ratiometric intensity-based and time-resolved studies in the visible and near-infrared wavelength region. Studies in PBS buffer solutions and in a model body liquid demonstrate the applicability of these nanosensors for the sensitive luminescence readout of TOP simultaneously at the same spatialposition. KW - Medical diagnostics KW - Sensor KW - Nanoparticle KW - Fluorescence KW - Nanosensor KW - Oxygen KW - Temperature KW - pH KW - Ratiometric KW - Lifetime KW - NIR KW - Cr(III) complex KW - Dye KW - FITC KW - Environment PY - 2019 DO - https://doi.org/10.1021/acs.analchem.8b05060 SN - 0003-2700 VL - 91 IS - 3 SP - 2337 EP - 2344 PB - ACS AN - OPUS4-47455 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Cui A1 - Resch-Genger, Ute T1 - Luminescent TOP nanosensors for simultaneously measuring temperature, oxygen, and pH at a single excitation wavelength N2 - Two nanosensors for simultaneous optical measurements of temperature (“T”), oxygen (“O”), and pH (“P”) have been designed. These “TOP” nanosensors are based on 100 nm-sized silica-coated polystyrene nanoparticles (PS-NPs) doped with the near infrared emissive oxygen- and temperature-sensitive chromium(III) complex ([Cr(ddpd)2][BPh4]3 CrBPh4)[1][2] and an inert reference fluorescence dye (Nile Red NR or 5,10,15,20tetrakis-(pentafluorophenyl) porphyrin TFPP) and are covalently labeled with the pHsensitive fluorophore fluorescein isothiocyanate (FITC). These emitters can be excited at the same wavelength and reveal distinguishable emission spectra suitable for ratiometric intensity-based and time-resolved studies in the visible and near infrared spectral region. The core-shell nanostructure of these sensors reveals high colloidal stability in various aqueous media. Studies in PBS buffer solutions and in a model body liquid demonstrate the applicability of the TOP nanosensors for optically detecting the three bioanalytically and biologically relevant analytes temperature, oxygen and pH simultaneously at the same position. T2 - ANAKON 2019 CY - Münster, Germany DA - 25.03.2019 KW - Sensor KW - Nanoparticle KW - Nanosensor KW - Fluorescence KW - Oxygen KW - Temperature KW - pH KW - Ratiometric KW - Lifetime KW - NIR KW - Cr(III) complex KW - FITC KW - Dye KW - Environment KW - Medical diagnostics PY - 2019 AN - OPUS4-47698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Cui T1 - Ratiometric luminescent TOP nanosensors for simultaneously measuring temperature, oxygen, and pH at a single excitation wavelength N2 - Two nanosensors for simultaneous optical measurements of temperature (“T”), oxygen (“O”), and pH (“P”) have been designed. These “TOP” nanosensors are based on 100 nm-sized silica-coated polystyrene nanoparticles (PS-NPs) doped with the near infrared emissive oxygen- and temperature-sensitive chromium(III) complex ([Cr(ddpd)2][BPh4]3 CrBPh4)[1][2] and an inert reference fluorescence dye (Nile Red NR or 5,10,15,20-tetrakis-(pentafluorophenyl) porphyrin TFPP) and are covalently labeled with the pH-sensitive fluorophore fluorescein isothiocyanate (FITC). These emitters can be excited at the same wavelength and reveal distinguishable emission spectra suitable for ratiometric intensity-based and time-resolved studies in the visible and near infrared spectral region. The core-shell nanostructure of these sensors reveals high colloidal stability in various aqueous media. Studies in PBS buffer solutions and in a model body liquid demonstrate the applicability of the TOP nanosensors for optically detecting the three bioanalytically and biologically relevant analytes temperature, oxygen and pH simultaneously at the same position. T2 - 2nd European Biosensor Symposium CY - Florenz, Italy DA - 18.02.2019 KW - Sensor KW - Nanoparticle KW - Nanosensor KW - Fluorescence KW - Oxygen KW - Temperature KW - pH KW - Ratiometric KW - Lifetime KW - NIR KW - Cr(III) complex KW - FITC KW - Dye KW - Environment KW - Medical diagnostics PY - 2019 AN - OPUS4-47700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Spode, Manfred A1 - Wang, Bin T1 - Monte Carlo simulation and evaluation of burst strength of pressure vessels N2 - The simulation of strength experiments by the Monte-Carlo method enables the numerical generation of data representing a complete populations of composite pressure vessels. In the case of composite pressure vessels used for hydrogen storage, properties like burst strength or fatigue cycle strength are of interest. This paper provides comprehensive information on how populations are generated and how samples can be taken and evaluated; it also explains how to determine the acceptance rate of random samples from simulated populations for passing the approval test "minimum burst pressure". A word of caution is also expressed regarding the evaluation of acceptance rates from a small sample. KW - Monte-Carlo simulation KW - Polar method KW - Composite cylinder KW - Burst strength KW - Acceptance rate PY - 2019 SN - 0025-5300 VL - 61 IS - 12 SP - 1152 EP - 1156 PB - Carl Hanser Verlag CY - München AN - OPUS4-49870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -