TY - JOUR A1 - Rhode, Michael A1 - Richter, Tim A1 - Schröpfer, Dirk A1 - Manzoni, Anna Maria A1 - Schneider, M. A1 - Laplanche, G. T1 - Welding of high-entropy alloys and compositionally complex alloys - an overview N2 - High-entropy alloys (HEAs) and compositionally complex alloys (CCAs) represent new classes of materials containing five or more alloying elements (concentration of each element ranging from 5 to 35 at. %). In the present study, HEAs are defined as single-phase solid solutions; CCAs contain at least two phases. The alloy concept of HEAs/CCAs is fundamentally different from most conventional alloys and promises interesting properties for industrial applications (e.g., to overcome the strength-ductility trade-off). To date, little attention has been paid to the weldability of HEAs/CCAs encompassing effects on the welding metallurgy. It remains open whether welding of HEAs/CCAs may lead to the formation of brittle intermetallics and promote elemental segregation at crystalline defects. The effect on the weld joint properties (strength, corrosion resistance) must be investigated. The weld metal and heat-affected zone in conventional alloys are characterized by non-equilibrium microstructural evolutions that most probably occur in HEAs/CCAs. The corresponding weldability has not yet been studied in detail in the literature, and the existing information is not documented in a comprehensive way. Therefore, this study summarizes the most important results on the welding of HEAs/CCAs and their weld joint properties, classified by HEA/CCA type (focused on CoCrFeMnNi and AlxCoCrCuyFeNi system) and welding process. KW - High-entropy alloy KW - Compositionally complex alloy KW - Welding KW - Properties KW - Review PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527068 DO - https://doi.org/10.1007/s40194-021-01110-6 SP - 1 EP - 15 PB - Springer Nature AN - OPUS4-52706 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - D'Agostino, G. A1 - Bergamaschi, L. A1 - Giordani, L. A1 - Oddone, M. A1 - Kipphardt, Heinrich A1 - Richter, Silke T1 - Use of instrumental neutron activation analysis to investigate the distribution of trace elements among subsamples of solid materials N2 - The results of analytical measurements performed with solid-sampling techniques are affected by the distribution of the analytes within the matrix. The effect becomes significant in case of determination of trace elements in small subsamples. In this framework we propose a measurement model based on Instrumental Neutron Activation Analysis to determine the relative variability of the amount of an analyte among subsamples of a material. The measurement uncertainty is evaluated and includes the counting statistics, the full-energy gamma peak efficiency and the spatial gradient of the neutron flux at the irradiation position. The data we obtained in a neutron activation experiment and showing the relative variability of As, Au, Ir, Sb and W among subsamples of a highly pure Rh foil are also presented. KW - Instrumental neutron activation analysis KW - Homogeneity KW - Rhodium KW - Uncertainty PY - 2014 SN - 0026-1394 SN - 1681-7575 VL - 51 SP - 1 EP - 6 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-30302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, Tim A1 - Delgado Arroyo, Diego A1 - Börner, Andreas A1 - Schröpfer, Dirk A1 - Rhode, Michael A1 - Lindner, T. A1 - Löbel, M. A1 - Preuß, B. A1 - Lampke, T. T1 - Ultrasonic assisted milling of a CoCrFeNi medium entropy alloy N2 - Medium and High Entropy Alloys (MEA/HEA) are recently developed material classes, providing manifold applications, e.g., due to extraordinary structural properties. In that connection, the machinability as important issue for the processing of these materials was not in the scientific focus. This study focusses on experimental analysis of milling process conditions including ultrasonic assisted milling (USAM) and their effects on the resulting surface integrity of equiatomic CoCrFeNi-MEA specimens. For that reason, milling parameters (cutting speed, feed per cutting edge) were systematically varied for both conventional milling and USAM. The surface integrity was analyzed in terms of topography, defects, and residual stresses. Especially USAM leads to a decrease of occurring cutting forces and, hence, to an improvement of the surface integrity. Beneficial effects were observed in terms of lower tensile residual stresses at high cutting speed and feed per cutting edge. KW - Medium entropy alloy KW - Ultrasonic Assisted Machining KW - Surface Integrity PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554458 DO - https://doi.org/10.1016/j.procir.2022.05.203 VL - 108 SP - 879 EP - 884 PB - Elsevier B.V. AN - OPUS4-55445 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alasonati, E. A1 - Fettig, I. A1 - Richter, Janine A1 - Philipp, Rosemarie A1 - Milačič, R. A1 - Sčančar, J. A1 - Zuliani, T. A1 - Tunç, M. A1 - Bilsel, M. A1 - Gören, A. A1 - Fisicaro, P. T1 - Towards tributyltin quantification in natural water at the Environmental Quality Standard level required by the Water Framework Directive N2 - The European Union (EU) has included tributyltin (TBT) and its compounds in the list of priority water pollutants. Quality standards demanded by the EU Water Framework Directive (WFD) require determination of TBT at so low concentration level that chemical analysis is still difficult and further research is needed to improve the sensitivity, the accuracy and the precision of existing methodologies. Within the frame of a joint research project “Traceable measurements for monitoring critical pollutants under the European Water Framework Directive” in the European Metrology Research Programme (EMRP), four metrological and designated institutes have developed a primary method to quantify TBT in natural water using liquid–liquid extraction (LLE) and species-specific isotope dilution mass spectrometry (SSIDMS). The procedure has been validated at the Environmental Quality Standard (EQS) level (0.2 ng L−1 as cation) and at the WFD-required limit of quantification (LOQ) (0.06 ng L−1 as cation). The LOQ of the methodology was 0.06 ng L−1 and the average measurement uncertainty at the LOQ was 36%, which agreed with WFD requirements. The analytical difficulties of the method, namely the presence of TBT in blanks and the sources of measurement uncertainties, as well as the interlaboratory comparison results are discussed in detail. KW - Tributyltin KW - Water Framework Directive KW - Metrological traceability KW - ICP-MS KW - Isotope dilution PY - 2016 DO - https://doi.org/10.1016/j.talanta.2016.07.056 SN - 0039-9140 SN - 1873-3573 VL - 160 SP - 499 EP - 511 PB - Elsevier B.V. AN - OPUS4-37407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - von Preetzmann, N. A1 - Eckmann, P. A1 - Tuma, Dirk A1 - Richter, M. T1 - Thermodynamics of LNG N2 - Densities of eight gravimetrically prepared ternary and quaternary gas mixtures consisting of methane, ethane, propane, and partially nitrogen were investigated along the four isotherms of –250, –230, –210, and –190 °F at pressures of 350, 500, 650, and 1000 psig using a cryogenic single-sinker densimeter. The experimental densities were compared to densities calculated by various models, namely the EOS-LNG fundamental Helmholtz equation of state, the COSTALD correlation, the Lee-Kessler-Plöcker equation of state, and the Peng-Robinson equation of state. The best performance was shown by the EOS-LNG equation of state which is capable of predicting the liquid densities within the specified uncertainty of the model of 0.05 %. The other models, however, showed significant differences that disqualify for calculation within the p,T-region investigated of the gas mixtures. KW - Density measurement KW - Liquefied natural gas-like mixtures KW - Cryogenic state KW - Single-sinker densimeter KW - Equations of state PY - 2020 SP - 1 EP - 55 AN - OPUS4-50741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mushtaq, S. A1 - Steers, E.B.M. A1 - Barnhart, D. A1 - Churchill, G. A1 - Kasik, M. A1 - Richter, Silke A1 - Pfeifer, Jens A1 - Putyera, K. T1 - The production of doubly charged sample ions by “charge transfer and ionization” (CTI) in analytical GD-MS N2 - Normally, in analytical GD-MS, the doubly charged metallic ion signals from the sample are several orders of magnitude less than the corresponding singly charged signals. However, we have observed that using a neon plasma, the M++ signals of some elements, which have double ionization energies close to the first ionization energy of neon, are of the same order as the M+ signal. Doubly charged ions may be produced directly in the discharge cell by electron ionization (EI), and also by two electron Penning ionization (TEP), but these processes cannot explain the above effect. In this paper, we suggest that an additional process named as ‘Charge Transfer and Ionization’ (CTI) produces such ions either in their ionic ground state or in an excited state. To confirm that this process is typical of the discharges used in GD-MS and not an artefact of any particular form of cell and ion extraction system, we have carried out comprehensive experimental measurements using three different GD-MS instruments, viz., Nu Astrum, VG9000 and ELEMENT GD and our results provide clear evidence for CTI. This is the first time the process has been identified as an ionization process in analytical GD-MS. CTI must be differentiated from Asymmetric Charge Transfer (ACT), which is a “selective” process and requires a close energy match (e.g. ΔE < 0.5 eV for a strong effect). On the other hand, CTI is “non-selective” in the sense that a close energy match is not required (e.g. a strong effect is observed with ΔE ∼ 2 eV), although the process only occurs for a limited number of elements, depending on the plasma gas used and the total energy required to doubly ionize the metallic atom. KW - Titanium KW - Glow discharge processes KW - Doubly charged ions KW - The charge transfer and ionization process (CTI) KW - Krypton KW - Neon PY - 2017 DO - https://doi.org/10.1039/C6JA00415F SN - 0267-9477 SN - 1364-5544 VL - 32 IS - 9 SP - 1721 EP - 1729 PB - Royal Society of Chemistry AN - OPUS4-41108 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, M. A1 - Bonse, Jörn A1 - Schultz, C. A1 - Pahl, H.-U. A1 - Endert, H. A1 - Rau, B. A1 - Stannowski, B. A1 - Quaschning, V. A1 - Stegemann, B. A1 - Fink, F. T1 - Single Wavelength Laser Processing for Monolithically Connected Si and CIGSe Thin Film Solar Cells T2 - Eröffnungsveranstaltung PVComB - Kompetenzzentrum Dünnschicht- und Nanotechnologie für Photovoltaik Berlin CY - Berlin, Germany DA - 2011-03-30 PY - 2011 AN - OPUS4-24207 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, S. A1 - Timmel, S. A1 - Richter, S. A1 - Werner, M. A1 - Gläser, M. A1 - Swatek, S. A1 - Braun, Ulrike A1 - Hagendorf, C. T1 - Silver nanoparticles cause snail trails in photovoltaic modules N2 - After some months of operation, a number of PV modules develop a discolouration defect called 'snail trails', or 'snail traces', which appear as irregular dark stripes across the cells. Whereas these traces were soon identified as discoloured silver contacts along the cell edges or at micro cracks, the chemical and mechanistic reasons for this phenomenon have not yet been resolved in detail. In this work we show that silver nanoparticles accumulating within the encapsulation foil cause the brownish discolouration, and that certain additives of encapsulation and back sheet foils trigger the formation of these nanoparticles. KW - Snail trails KW - Cell cracks KW - Encapsulation foil KW - Ag contact finger KW - Nanoparticles PY - 2014 DO - https://doi.org/10.1016/j.solmat.2013.11.013 SN - 0927-0248 VL - 121 SP - 171 EP - 175 PB - Elsevier B.V. CY - Amsterdam [u.a.] AN - OPUS4-30059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, M. A1 - Trunschke, A. A1 - Bentrup, U. A1 - Brzezinka, Klaus-Werner A1 - Schreier, E. A1 - Schneider, M. A1 - Pohl, M.-M. A1 - Fricke, R. T1 - Selective Catalytic Reduction of Nitric Oxide by Ammonia over Egg-Shell MnOx/NaY Composite Catalysts N2 - A novel composite catalyst system for the selective catalytic reduction (SCR) of NOx by NH3 is described operating at temperatures lower than 470 K in the presence of water with NO conversions of 80–100% at space velocities of 30,000–50,000 h-1. The catalyst is prepared by egg-shell precipitation of MnO2 on the external surface of zeolite NaY. Structural and thermal stability of precipitated MnO2 as well as of the MnO2/NaY composite catalyst were characterized by N2 adsorption, X-ray diffraction, laser Raman spectroscopy, temperature-programmed reduction, and electron microscopy. MnO2 precipitated on zeolite NaY (15 wt% loading) retained its amorphous state up to calcination temperatures of 775 K. The zeolite component remained structurally intact. Calcination at higher temperatures destroyed the zeolite structure and transformed MnO2 into Mn3O4. DRIFT spectroscopic investigations revealed the presence of symmetric O=N—O—N=O species formally corresponding to N2O3 on the composite catalyst after contact with NO. Catalytic measurements under integral flow conditions showed that the catalyst performance is associated with a close coupling of nitrite formation and its drain off from equilibria with NO/NO2 and nitrate by ammonia. Several results are in line with the “diazotation” mechanism, including NH3 protonation to NH4+, whereas prevailing Lewis acid sites should enable NH3 activation via amide species, thus leading to a parallel “amide/nitrosamide” SCR reaction route. The activity-temperature profile fulfills the requirements of a low-temperature NOx reduction catalyst for mobile diesel engines if an ammonia supply is implemented “on board,” e.g., by urea decomposition. PY - 2002 DO - https://doi.org/10.1006/jcat.2001.3468 SN - 0021-9517 SN - 1090-2694 VL - 206 SP - 98 EP - 113 PB - Acad. Press CY - San Diego, Calif. AN - OPUS4-1638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Altmann, Korinna A1 - Abusafia, A A1 - Bannick, C-G A1 - Braun, U A1 - Crasselt, Claudia A1 - Dittmar, S A1 - Fuchs, M A1 - Gehde, M A1 - Hagendorf, C A1 - Heller, C A1 - Herper, D A1 - Heymann, S A1 - Kerndorff, A A1 - Knefel, M A1 - Jekel, M A1 - Lelonek, M A1 - Lunkenbein, T A1 - Obermaier, N A1 - Manhart, M A1 - Meurer, Maren A1 - Miclea, P-T A1 - Paul, A A1 - Richter, S A1 - Ricking, M A1 - Rohner, C A1 - Ruhl, A A1 - Sakai, Y A1 - Saravia Arzabe, C A1 - Scheid, C A1 - Schmitt, M A1 - Schnarr, M A1 - Schwertfirm, F A1 - Steinmetz, H A1 - Wander, Lukas A1 - Wiesner, Yosri A1 - Zechmeister, L T1 - RUSEKU - Repräsentative Untersuchungsstrategien für ein integratives Systemverständnis von spezifischen Einträgen von Kunststoffen in die Umwelt : Abschlussbericht N2 - Im Verbundprojekt RUSEKU wurde die Probenahme von Wasserproben entscheidend weiterentwickelt. Wichtig ist hierbei zu gewährleisten, dass genügend Merkmalsträger in jeder Probe untersucht werden. Es muss daher eine für den Probenahmeort repräsentative Beprobung hinsichtlich des Wasservolumens in Abhängigkeit der Partikelanzahl gewährleistet sein. Das Hauptaugenmerk lag im vorliegenden Projekt auf einer praxisnahen Beprobungsstrategie. Es wurden verschiedene Konzepte ausprobiert. • Grundsätzlich hat sich gezeigt, dass eine Stichprobe eine Momentaufnahme des MP-Massengehaltes zeigt. Es wird eine hohe Statistik, also eine Vielzahl an Messungen am gleichen Probenahmeort, benötigt, um eine valide Aussage über den MP-Gehalt zu machen. • Es zeigt sich, dass eine integrale Probenahme über mehrere Wochen mit dem SK routinemäßig möglich ist. Die erfassten MP-Massen sind reproduzierbar und robust. • Die DFZ ist für Stichproben geeignet. Partikel < 50 µm werden eventuell unterschätzt • Die fraktionierte Filtration kann für Stich- und Mischproben direkt im Feld genutzt werden. Fraktionen von 10 und 5 µm werden später im Labor Vakuum filtriert. Es erfolgt eine Fraktionierung der Probe mit Siebmaschenweiten von 1000, 500, 100, 50, 10 und 5 µm. • Die fraktionierte Filtration kann auch anschließend an die Beprobung mit dem SK zur Anwendung kommen. Wird die mit dem SK gewonnene Wasserprobe fraktioniert filtriert, kann neben einem MP-Gesamtgehalt auch eine Einschätzung über die Partikelgrößen gewonnen werden. • Für Wässer mit geringen Partikelzahlen wurde ein Messfiltertiegel entwickelt. Dieser hat eine Maschenweite von 6 µm. Seine Anwendung kann mögliche Verluste beim Transferieren vom Probenahmetool zum Messgefäß und mögliche Kontaminationen reduzieren. Die Optimierung der Probenahmestrategie wurde durch Modellversuche und Simulationen unterstützt. Modellversuche zum Sinkverhalten und Simulationen von MP in realen Gewässern verdeutlichten das komplexe Verhalten der Partikel. Es konnte gezeigt werden, dass Partikel ab einer bestimmten Größe (und kleiner) bei genügend starker Turbulenz sich in der Wassersäule unabhängig von ihrer Dichte verhalten und so auch MP mit kleiner Dichte (z.B. PE) in der gesamten Wassersäule zu finden sind. Es konnte mit dem TEM die Existenz von NP gezeigt werden. Ein wesentlicher Aspekt des RUSEKU Projektes war die Beprobung realer Kompartimente. Beprobt wurde neben Oberflächengewässern, das urbane Abwassersystem der Stadt Kaiserslautern, Waschmaschinenabwasser und Flaschenwasser. • In Oberflächengewässern wurde hauptsächlich PE gefunden. Je nach Probe und Gewässer konnten auch PP, PS, PET, PA, SBR und Acrylate nachgewiesen werden. • Im urbanen Abwassersystem der Stadt Kaiserslautern konnte an allen Probenahmestandorten MP nachgewiesen werden. Es wurde hauptsächlich PE, neben geringeren Mengen an PP, PS und SBR gefunden. Nach einem Regenereignis war der SBR Anteil deutlich erhöht. • Die Beprobung eines realen Wäschepostens, bestehend aus T-Shirts und Hemden mit PA/CO oder PES/CO Mischgewebe, zeigte einen PA- und PES-Austrag im Waschwasser. Der überwiegende Teil der detektierten Fasern ist aber auf Baumwolle zurückzuführen. Reine gravimetrische Messungen zur Detektion von MP führen zu einer starken Überschätzung. • In Flaschenwasser (PET-Flaschen) konnte MP detektiert werden. PET wurde nur im stillen Mineralwasser, nicht in Mineralwasser mit Kohlensäure gefunden werden. Teilweise wurde auch das MP-Material des Verschlusses im Wasser detektiert. • Für Luftproben konnte ein Aufbau zur größenselektiven Beprobung getestet werden. Neben der Probenahme hat das Projekt auch gezeigt, dass die TED-GC/MS geeignet für die MP-Detektion im Routinebetrieb ist. Die TED-GC/MS konnte weiter optimiert werden. Es wurden MP-Massen bestimmt. Im Projekt wurden erste realitätsnahe Referenzmaterialien für die MP Detektion hergestellt. Die Herstellung von realitätsnahen Polymeren in ausreichender Homogenität und Menge hat sich als große Herausforderung herausgestellt. KW - Mikroplastik KW - Probennahme KW - TED-GC/MS KW - Fraktionierte Filtration KW - Mikroplastikreferenzmaterial PY - 2022 SP - 1 EP - 201 AN - OPUS4-57800 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, Matthias A1 - Mull, Birte A1 - Horn, Wolfgang A1 - Brödner, Doris A1 - Mölders, N. A1 - Renner, M. T1 - Reproducibly emitting reference material on thermoplastic polyurethane basis for quality assurance/quality control of emission test chamber measurements N2 - Volatile Organic Compounds (VOC) are ubiquitous in the indoor air since they are emitted from materials used indoors. Investigations of these materials are mostly carried out in emission test chambers under controlled climatic conditions. Reference materials are an important tool for quality assurance/Quality control of emission test chamber measurements but so far they are not commercially available. In this study, a new approach was tested to develop an appropriate reference material with homogenous and reproducible emission of the VOC with well measurable air concentrations in emission test Chambers larger than 20 L at air change rates of 0.5 - 1 /h. Thermoplastic Polyurethane (TPU) was selected as Matrix material which was impregnated with 2,2,4- trimethyl-1,3-pentanediol monoisobutyrate (texanol) as test VOC using compressed carbon dioxide. An optimization of the impregnation parameters such as temperature, pressure, time, VOC injection volume and TPU sample size was performed until the targeted area specific Emission rate (SERa) value was reached. Further aspects like process control, storage effects and correlation of the sample size to the emission rate were investigated. It was found that the SERa immediately after sample preparation were not reproducible between the batches but became unified 10 days after loading into the test chamber indicating the necessity of aging before use. SERa between 13,000 and 18,000 mg m-2 h-1 were obtained, and the impregnated materials could be well stored in aluminum-coated polyethylene foil for at least seven weeks without significant losses. Furthermore, the impregnation of styrene and the SVOC 2,6-diisopropylnaphthalene was tested. KW - Reference material KW - Emissions testing KW - Volatile organic compounds KW - Polymer material KW - CO2 assisted impregnation PY - 2017 DO - https://doi.org/10.1016/j.buildenv.2017.06.005 SN - 0360-1323 SN - 1873-684X VL - 122 SP - 230 EP - 236 PB - Elsevier AN - OPUS4-40646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Horn, Wolfgang A1 - Wilke, Olaf A1 - Mull, B. A1 - Richter, Matthias A1 - Brödner, Doris A1 - Mölders, N. A1 - Renner, M. T1 - Reproducibly emitting reference material for quality assurance/quality control of emission test chamber measurements N2 - Volatile Organic Compounds (VOC) are ubiquitous in the indoor air, since they emit from materials used indoors. Investigations of these materials are mostly carried out in test chambers under controlled climatic conditions. Quality control of these test chamber measurements is important but there is a lack of commercially available homogenous reference materials as required for round robin tests or quality assurance of laboratories. The approach of the present study is the impregnation of a supporting material with VOC, which are reproducibly released in measurable chamber air concentrations under standardised test conditions. A polymer made of Thermoplastic Polyurethane (TPU) was chosen as carrier material. It was impregnated with the VOC trimethyl pentanediol isobutyrat (texanol). T2 - Healthy Buildings 2017 Europe CY - Lublin, Poland DA - 02.07.2017 KW - Emissions testing KW - Volatile organic compounds KW - Polymeric material KW - CO2 assisted impregnation PY - 2017 SN - 978-83-7947-232-1 SP - Paper 0172, 1 EP - 2 AN - OPUS4-42348 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poppenberg, J. A1 - Richter, S. A1 - Traulsen, C.H.-H. A1 - Darlatt, Erik A1 - Baytekin, B. A1 - Heinrich, T. A1 - Deutinger, P.M. A1 - Huth, K. A1 - Unger, Wolfgang A1 - Schalley, C.A. T1 - Programmable multilayers of nanometer-sized macrocycles on solid support and stimuli-controlled on-surface pseudorotaxane formation N2 - Mechanically interlocked molecules (MIMs) such as rotaxanes and catenanes are capable of mechanical motion on the nanoscale and are therefore promising prototypes for molecular machines in recent nanotechnology. However, most of the existing examples are isotropically distributed in solution, which prohibits concerted movement and with it the generation of macroscopic effects. Thus, arranging them in ordered arrays is of huge interest in recent research. We report the deposition of quite densely packed multilayers of tetralactam macrocycles on gold surfaces by metal-coordinated layer-by-layer self-assembly. Linear dichroism effects in angle-resolved NEXAFS spectra indicate a preferential orientation of the macrocycles. The sequence of the metal ions can be programmed by the use of different transition metal ions at each deposition step. Additionally, reversible on-surface pseudorotaxane formation was successfully realized by repeated uptake and release of axle molecules inside the macrocycles cavities. KW - ISO KW - Standard KW - Surface analysis KW - Imaging PY - 2013 DO - https://doi.org/10.1039/c3sc50558h SN - 2041-6520 SN - 2041-6539 VL - 4 SP - 3131 EP - 3139 PB - RSC CY - Cambridge AN - OPUS4-29049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poppenberg, J. A1 - Richter, S. A1 - Traulsen, Ch. H.-H. A1 - Darlatt, Erik A1 - Baytekin, B. A1 - Heinrich, Thomas A1 - Deutinger, P. M. A1 - Huth, K. A1 - Unger, Wolfgang A1 - Schalley, Ch. T1 - Programmable multilayers of nanometer-sized macrocycles on solid support and stimuli-controlled on-surface pseudorotaxane formation N2 - Mechanically interlocked molecules (MIMs) such as rotaxanes and catenanes are capable of mechanical motion on the nanoscale and are therefore promising prototypes for molecular machines in recent nanotechnology. However, most of the existing examples are isotropically distributed in solution, which prohibits concerted movement and with it the generation of macroscopic effects. Thus, arranging them in ordered arrays is of huge interest in recent research. We report the deposition of quite densely packed multilayers of tetralactam macrocycles on gold surfaces by metal-coordinated layer-by-layer self-assembly. Linear dichroism effects in angle-resolved NEXAFS spectra indicate a preferential orientation of the macrocycles. The sequence of the metal ions can be programmed by the use of different transition metal ions at each deposition step. Additionally, reversible on-surface pseudorotaxane formation was successfully realized by repeated uptake and release of axle molecules inside the macrocycles cavities. KW - NEXAFS KW - XPS KW - Supramolecular Chemistry KW - Multilayers KW - Pyridine KW - UV/Vis KW - Macrocycles KW - Pseudorotaxanes PY - 2013 DO - https://doi.org/10.1039/c3sc50558h VL - 4 IS - 8 SP - 3131 EP - 3139 AN - OPUS4-42668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Musyanovych, A. A1 - Grimmer, Christoph A1 - Sadak, A. E. A1 - Heßling, L. A1 - Bilsel, M. A1 - Horn, Wolfgang A1 - Richter, Matthias T1 - Polymeric Capsules with VOCs for Controlled Emission N2 - Micro-(nano-)encapsulation technology involves building of a barrier between the core and the environment and offers a number of benefits to preserve the functional and physicochemical properties of core material. Tremendous progress has been made in synthesizing well-defined capsules to achieve desired properties such as particle size, chemical composition, and controlled release of the payload. Encapsulation of volatile organic compounds (VOCs) that could evaporate with a defined rate is of immense interest for application in emission reference materials (ERM). These are urgently needed for quality assurance and quality control purposes (QA/QC) required by test standards for the determination of chemical emissions of construction and other materials for interior use. As such ERMs are hardly available on the market, the EU-funded EMPIR project MetrIAQ [1] was started to fill this gap by developing a material with temporally constant emission of VOCs typically found in indoor air. Different capsules in a size range between 5 and 50 μm were synthesized through an interfacial polyaddition/polycondensation reaction in direct (water-in-oil) system. As VOC several types of hydrophobic liquid materials were used. After synthesis, the morphology and physicochemical properties of capsules were characterized by electron microscopy, FTIR and DSC/TGA. An encapsulation efficiency up to 90% could be reached. The emission kinetic of volatile agents was studied in emission test chambers at 23 °C and 50% RH for 14 days. First results indicate that variation of the cross-linking grade of the shell material is one important parameter to adjust the desired emission rate. The overall aim is to achieve a consistent emission profile that decreases by less than 10 % over a target period of at least 14 days. T2 - 36th European Colloid & Interface Society Conference CY - Chania, Crete, Greece DA - 04.09.2022 KW - Capsules KW - Volatile organic compound KW - Polymer KW - Material emissions KW - Reference materials PY - 2022 AN - OPUS4-56039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ressel, P. A1 - Hao, P.H. A1 - Park, M.H. A1 - Yang, Z. C. A1 - Wang, L.C. A1 - Österle, Werner A1 - Kurpas, P. A1 - Richter, E. A1 - Kuphal, E. A1 - Hartnagel, H.L. T1 - Pd/Sb(Zn) and Pd/Ge(Zn) Ohmic Contacts on p-Type Indium Gallium Arsenide: The Employment of the Solid Phase Regrowth Principle to Achieve Optimum Electrical and Metallurgical Properties N2 - The development of two metallizations based on the solid-phase regrowth principle is presented, namely Pd/Sb(Zn) and Pd/Ge(Zn) on moderately doped In0.53Ga0.47As (p=4×1018 cm-3). Contact resistivities of 2–3×10-7 and 6–7×10-7 ?cm2, respectively, have been achieved, where both systems exhibit an effective contact reaction depth of zero and a Zn diffusion depth below 50 nm. Exhibiting resistivities equivalent to the lowest values of Au-based systems in this doping range, especially Pd/Sb(Zn) contacts are superior to them concerning metallurgical stability and contact penetration. Both metallizations have been successfully applied for contacting the base layer of InP/In0.53Ga0.47As heterojunction bipolar transistors. KW - Ohmic contacts KW - Indium gallium arsenide KW - InP/InGaAs heterojunction bipolar transistor KW - Solid-phase regrowth KW - Pd/Ge contacts KW - Pd/Sb contacts KW - Backside secondary ion mass spectrometry (SIMS) PY - 2000 DO - https://doi.org/10.1007/s11664-000-0189-y SN - 0361-5235 SN - 1543-186X VL - 29 IS - 7 SP - 964 EP - 972 PB - TMS CY - Warrendale, Pa. AN - OPUS4-7642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schultz, C. A1 - Schüle, M. A1 - Richter, M. A1 - Pahl, H.-U. A1 - Endert, H. A1 - Bonse, Jörn A1 - Dirnstorfer, I. A1 - Rau, B. A1 - Schlatmann, R. A1 - Quaschning, V. A1 - Fink, F. A1 - Stegemann, B. T1 - P1, P2 and P3 structuring of CIGSe solar cells with a single laser wavelength N2 - Manufacturing of CIGSe thin film solar modules involves typically one laser structuring step (P1) and two mechanical structuring steps (P2 and P3) for serial interconnection. In our approach, complete laser structuring is successfully demonstrated by application of short nanosecond laser pulses (<10 ns) with a single, visible wavelength of 532 nm. The P1 and the P3 trenches are scribed by induced and direct ablation, respectively. For the P2 scribe, the thermal input of the ns laser pulses is used to transform the CIGSe absorber layer locally into a highly conductive compound to provide proper electrical interconnection. These findings promise further simplification and flexibility to thin film solar cell production. T2 - 26th European photovoltaic solar energy conference and exhibition CY - Hamburg, Germany DA - 05.09.2011 KW - Laser processing KW - Nanosecond pulses KW - Ablation KW - Cu(InGa)Se2 KW - Electrical properties PY - 2011 SN - 3-936338-27-2 DO - https://doi.org/10.4229/26thEUPVSEC2011-3AV.1.35 SP - 2540 EP - 2543 AN - OPUS4-24998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stegemann, B. A1 - Richter, M. A1 - Schultz, C. A1 - Pahl, H.-U. A1 - Endert, H. A1 - Bonse, Jörn A1 - Rau, B. A1 - Quaschning, V. A1 - Fink, F. T1 - One wavelength fits all N2 - Structuring of Thin-film Solar Cells with a Single Laser Wavelength Structuring of a PV module into a number of cells is necessary to lower the current and to increase the voltage, and is typically accomplished with nanosecond laser pulses of different wavelengths. Duetothe many available laser sources, complex and expensive scribing Setups are necessary. To overcome this a concept for laser structuring of thin-film PV modules using a single wavelength allows prediction ofthe ablation behaviourfor a given laser pulse energy. KW - Thin-film solar cells KW - Nanosecond laser ablation KW - 532 nm wavelength KW - Laser scribing KW - Damage threshold PY - 2011 SN - 1869-8913 VL - 2 IS - 6 SP - 46 EP - 48 PB - Hüthig CY - Heidelberg AN - OPUS4-24158 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Regina A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc A1 - Schilling, M. T1 - Numerical method of active thermography for the reconstruction of back wall geometry N2 - The paper presents numerical methods to detect and classify defects and inhomogeneities by means of active thermography. The objective is to determine the wall thickness of structure elements with an inaccessible back wall, for example, of pipes or Containers. As test specimens we used approximately 2 cm thick PVC samples with spatial variations in the back wall geometry. Flash lamps provided the heating. To know the thickness of the wall, we used two inversion methods and compared the results achieved. One is an iterative echo defect shape method and already tested on Steel test specimens with good reconstruction results. The second one is the Levenberg-Marquardt method, applied here to thermographic data for non-destructive testing. Since data capturing using active thermography and the presented numerical methods can easily be automated, the combination of these two procedures is a promising approach providing a broad area of application. T2 - 6th Workshop 'NDT in progress' CY - Prague, Czech Republic DA - 10.10.2011 KW - Impulse-thermography KW - Inversion KW - Levenberg-Marquardt method KW - Echo defect shape KW - Defect shape reconstruction PY - 2011 SN - 978-80-214-4339-6 IS - Chapter 8 SP - 245 EP - 252 AN - OPUS4-25144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shaik, A.-A. A1 - Richter, M. A1 - Kricheldorf, H. A1 - Krüger, Ralph-Peter T1 - New polymer syntheses - CIX. Biodegradable, alternating copolyesters of terephthalic acid, aliphatic dicarboxylic acids, and alkane diols N2 - Copolyesters with an alternating sequence of terephthalic acid and aliphatic dicarboxylic acids were prepared with three different methods. First, dicarboxylic acid dichlorides were reacted with bis(2-hydroxyethyl)terephthalate (BHET) in refluxing 1,2-dichlorobenzene. Second, the same monomers were polycondensed at 0-20 °C in the presence of pyridine. Third, dicarboxylic acid dichlorides and silylated BHET were polycondensed in bulk. Only this third method gave satisfactory molecular weights. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed that the copolyesters prepared by the pyridine and silyl methods might have contained considerable fractions of cyclic oligoesters and polyesters despite the absence of transesterification and backbiting processes. The alternating sequences and thermal properties were characterized with 1H NMR spectroscopy and differential scanning calorimetry measurements, respectively. In agreement with the alternating sequence, all copolyesters proved to be crystalline, but the crystallization was extremely slow [slower than that of poly(ethylene terephthalate)]. A second series of alternating copolyesters was prepared by the polycondensation of silylated bis(4-hydroxybut- yl)terephthalate with various aliphatic dicarboxylic acid dichlorides. The resulting copolyesters showed significantly higher rates of crystallization, and the melting temperatures were higher than those of the BHET-based copolyesters. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3371-3382, 2001 KW - Poly(ethylene terephthalate) KW - Poly(butylene terephthalate) KW - Alternating sequence KW - Macrocycles KW - Crystallization KW - Biodegradable polyesters PY - 2001 DO - https://doi.org/10.1002/pola.1320 SN - 0360-6376 SN - 0887-624X VL - 39 IS - 19 SP - 3371 EP - 3382 PB - Wiley CY - Hoboken, NJ AN - OPUS4-2173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -