TY - CONF A1 - Streeck, C. A1 - Dietrich, Paul A1 - Fischer, Tobias A1 - Rurack, Knut A1 - Unger, Wolfgang A1 - Beckhoff, B. T1 - Characterization of bio-molecular nano-layers by means of reference-free X-ray Spectrometry N2 - Characterization of bio-molecular nano-layers by means of reference-free X-ray Spectrometry An increasing field of application, e.g. in biotechnology is the dedicated adjustment of surface properties by functionalization with organic molecules. For a detailed understanding and further development of such nano-layers, a quantitative determination of the surface density of molecular species is required. By means of reference-free X-Ray Fluorescence (XRF) spectrometry such surfaces can be analyzed quantitatively by detecting specific marker elements. Using calibrated instrumentation and a quantification approach based on atomic fundamental parameters a SI-traceable quantitative analysis without any calibration sample or reference material is possible. A chemical analysis of molecular bonds can be accomplished by X-Ray Absorption Spectroscopy in the Near-Edge region (NEXAFS). Especially in the soft X-ray range an access to relevant light elements like Carbon C, Nitrogen N and Oxygen is possible. Here, aminated surfaces with varying densities of amino groups prepared from binary mixtures of silanes were investigated. In a complementary analysis by X-Ray Photoelectron Spectroscopy (XPS) and Fluorescence measurements based on laser-excitation in the optical light spectrum the functional-group density of silane monolayers were determined. The nitrogen atom in the head-group of the silane-molecule could be used as specific marker for the reference-free quantitative XRF analysis and were used for traceable calibration of XPS and Fluorescence Spectroscopy. T2 - EMRS Spring Meeting 2017, ALTECH 2017, Symposium S, Analytical techniques for precise characterization of nano materials CY - Strasbourg, France DA - 22.05.2017 KW - XPS KW - XRF KW - Amino silane film KW - Traceability PY - 2017 AN - OPUS4-43374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Beckhoff, B. A1 - Unger, Wolfgang T1 - Quantitative XRF analysis of industrial thin film samples by calibration using thin film RMs N2 - X-ray fluorescence (XRF) analysis is a well suited methodology for thin film analysis. With XRF the mass deposition of elements can be non-destructively determined. By knowledge of the density of the thin film as well the thickness can be given. In the field of industrial thin film manufacturing various material systems and layer structures are used. the analysis relies on well-known calibration samples or even reference materials to determine absolute analytical results from the measurement values recorded. Within this concept of chemical traceability the calibration sample has to be as similar as possible to the industrial thin film sample with respect to the spatial distribution of elemental composition in order to minimize matrix effects or analysis related uncertainties. The procurement of such certified similar calibration samples or reference materials including their required traceability is a challenge due to limited number of available calibration samples or reference materials, in particular at the nanoscale. There are only few providers of calibration standards for layer or coating thicknesses which are suitable for XRF analysis. The limited number of available certified reference materials (CRMs) for XRF thin film analysis and in parallel the growing market of novel thin film materials induces a growing gap of required calibration samples for XRF analysis. The exploitation of process-near samples benefits from a leverage effect: on one hand reference materials are needed for calibration and alignment procedures for X-ray fluorescence devices. They are customized for the special need of the end-user, e.g. a company producing thin film solar cells. On the other hand the market for EDXRF devices develops positively by providing novel thin film calibration samples for industry and end user-related production processes or application. Two aspects are hereby being addressed; the improvement of product quality which in certain sectors like aerospace and automotive industry directly translates to product safety as well as the expansion of the sales potential of EDXRF measuring devices. T2 - Annual Meeting ISO TC 201 SC10 CY - Brescia, Italy DA - 17.09.2017 KW - XRF KW - Calibration KW - Traceability PY - 2017 AN - OPUS4-43375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Grötzsch, D. A1 - Witte, K. A1 - Dietrich, Paul A1 - Malzer, W. A1 - Nutsch, A. A1 - Stiel, H. A1 - Unger, Wolfgang A1 - Kanngießer, B. A1 - Beckhoff, B. T1 - A liquid cell for the analysis of biomolecules (e.g. proteins, chlorophyll) using soft X-ray excitation N2 - For versatile applications, including vacuum instrumentation, a liquid cell was developed. Using ultra-thin windows, this cell enables X-ray Absorption spectrometry in the soft X-ray range which is in particular interesting for the analysis of organic molecules in liquids or at the solid-liquid interface. NEXAFS of a protein at N K-edge and of chlorophyll a at Mg K-edge is demonstrated. T2 - 8th Jouint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 7.12.2016 KW - XAS KW - NEXAFS KW - Liquid cell KW - Chlorophyll PY - 2016 AN - OPUS4-38711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Nutsch, A. A1 - Beckhoff, B. A1 - Rurack, Knut A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Unger, Wolfgang T1 - Reference-free quantification of functional groups on surfaces for bioanalytical applications by total reflection X-ray fluorescence analysis N2 - For the development of biosensors or microarrays in biotechnology functionalized surfaces e.g. aminated glass surfaces can be used. Knowledge of the quantity of primary reactive groups on such surfaces is indispensable for a defined secondary modification with commonly biochemical entities, eventually resulting in more reliably tailored surfaces with better controlled properties. Here, we investigated aminated glass surfaces with varying densities of amino groups prepared from binary mixtures of silanes. Subsequent labeling of the amino groups with a fluorophore containing a high number of fluorine atoms allows complementary quantification of the organic groups by optical fluorescence spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and traceable Total-Reflection X-ray Fluorescence analysis (TXRF). Reference-free TXRF with soft X-ray excitation determines the mass deposition of elements such as carbon, nitrogen and fluorine, yielding the areal density of primary functional groups on the surface. The TXRF-measurements were performed at the PTB beamline for undulator radiation at the electron storage ring BESSY II which provides monochromatic soft X-rays with high spectral purity and photon flux. This approach allows the calibration of optical fluorescence spectroscopy and XPS to deliver traceable quantitative data. T2 - European Conference on X-Ray Spectrometry (EXRS-2014) CY - Bologna, Italien DA - 2014-06-15 PY - 2014 AN - OPUS4-34664 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Held, Felix A1 - Robens-Radermacher, Annika A1 - Unger, Jörg F. A1 - Reese, Stefanie T1 - Efficient model updating in structural analysis using proper generalized decomposition N2 - The proper generalized decomposition is combined with a Bayesian model updating to identify unknown material parameters for mechanical structures. A convergence analysis for the Bayesian updating procedure is finally presented. T2 - ECCOMAS YIC 2019 5th Young Investigators Conference CY - Krakau, Poland DA - 01.09.2019 KW - Efficient model updating KW - Structural analysis PY - 2019 AN - OPUS4-48902 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Seim, C. A1 - Streeck, C. A1 - Wansleben, M. A1 - Hornemann, A. A1 - Schwibbert, Karin A1 - Unger, Wolfgang A1 - Vorng, J. L. A1 - Kästner, B. A1 - Dietrich, P. A1 - Thissen, A. A1 - Beckhoff, B. T1 - EMPIR project Metrology vs. Bad Bugs aims to provide urgently needed metrology to quantitatively measure localization and penetration of antibiotics and biocides in bacteria and biofilms N2 - An overview of ongoing reference-free X-ray spectrometry, near-ambient pressure X-ray photoelectron spectroscopy and Fourier-Transform infrared micro-spectroscopy studies on the penetration of biocides/antibiotics into bacteria and biofilms is given. T2 - Ninth Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 13.12.2017 KW - Biofilms KW - Alginate KW - XRF KW - FTIR KW - NAP-XPS PY - 2017 AN - OPUS4-43465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Streeck, C. A1 - Nutsch, A. A1 - Weser, J. A1 - Fischer, Tobias A1 - Dietrich, Paul A1 - Rurack, Knut A1 - Unger, Wolfgang A1 - Beckhoff, B. T1 - Reference-free total reflection X-ray fluorescence analysis for quantification of functional groups on surfaces for bioanalytical applications T2 - 6th Joint BER II and BESSY II User Meeting of HZB CY - Berlin, Germany DA - 2014-12-04 PY - 2014 AN - OPUS4-32390 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oran, Umut A1 - Swaraj, Sufal A1 - Lippitz, Andreas A1 - Schulze, Rolf-Dieter A1 - Unger, Wolfgang T1 - Characteriazation of Plasma-deposited Ethylene, Ally-alcohol and Ethylene-Ally-alcohol copolymer Films by Time-of-Flight Static Secondary lon Mass Spectrometry (TOF-SIMS) T2 - 10th European Conference on Applications of Surface and Interface Analysis (ECASIA '03) CY - Berlin, Germany DA - 2003-09-05 PY - 2003 AN - OPUS4-5025 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzlechner, Gerald A1 - Hussels, M. A1 - Reihardt, P. A1 - Jungnickel, H. A1 - Kummrow, A. A1 - Neukammer, J. A1 - Unger, Wolfgang T1 - Metrology for monitoring infectious diseases: flow cytometer, XPS and TOF-SIMS characterization of DNA adhesion losses on micro fluidic PCR devices T2 - Angewandte Oberflächen Analytik Tagung, AOFA 18 CY - Kaiserslautern, Germany DA - 2014-09-29 PY - 2014 AN - OPUS4-31684 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Titscher, Thomas A1 - Unger, Jörg F. A1 - Oliver, Javier T1 - High-order cycle jump integration of a concrete fatigue damage model N2 - Fatigue models that accurately resolve the complex three-dimensional failure mechanisms of concrete are numerically expensive. Especially the calibration of fatigue parameters to existing Wöhler lines requires solving for thousands or millions of cycles and a naive cycle-by-cycle integration is not feasible. The proposed adaptive cycle jump methods provide a remedy to this challenge. They greatly reduce the numerical effort of fatigue simulations and provide the basis for a development of those models. T2 - 8th GACM Colloquium on Computational Mechanics CY - Kassel, Germany DA - 28.08.2019 KW - Time scale separation KW - Cycle jump KW - Fatigue damage PY - 2019 AN - OPUS4-52191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -