TY - CONF A1 - Fu, B. A1 - Shen, J. A1 - Suhuddin, U. A1 - Su, H. A1 - dos Santos, J. A1 - Rethmeier, Michael T1 - Microstructure and mechanical properties of a modified refill friction stir spot welds of AM50 magnesium alloy N2 - Magnesium (Mg) alloys have attracted much attention due to their merits of meeting requirements of lightweight, energy-efficient and environmental friendly engineering. In this study, a modified refill friction stir spot welding (refill-FSSW) method is proposed to weid AMSO Mg alloy, in which pin and sleeve rotate at different states. Effects of process parameters on the microstructure, material flow, and mechanical properties of welds were studied. Results showed that, the modified refill-FSSW technology could enhance the intennixing of material by changing the flow state. Lap shear strength of welds could be significantly improved with changed failure modes. The modified refill FSSW technology is a competitive welding method for Mg alloy. T2 - 7th International Conference on Welding Science and Engineering in conjunction with 3rd International Symposium on Computer-Aided Welding Engineering CY - Jinan, China DA - 18.10.2017 KW - Refill friction stir spot welding KW - Friction spot welding KW - Magnesium KW - Microstructure KW - Mechanical properties PY - 2017 SP - 203 EP - 206 AN - OPUS4-43234 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shen, Z. A1 - Röhr, Holger A1 - Rurack, Knut A1 - Uno, H. A1 - Spieles, Monika A1 - Schulz, Burkhard A1 - Reck, Günter A1 - Ono, N. T1 - Boron-Diindomethene (BDI) Dyes and Their Tetrahydrobicyclo Precursors - en Route to a New Class of Highly Emissive Fluorophores for the Red Spectral Range N2 - The X-ray crystallographic, optical spectroscopic, and electrochemical properties of a newly synthesized class of boron-diindomethene (BDI) dyes and their tetrahydrobicyclo precursors (bc-BDP) are presented. The BDI chromophore was designed to show intensive absorption and strong fluorescence in an applicationary advantageous spectral range. Its modular architecture permits fusion of a second subunit, for example, a receptor moiety to the dye's core to yield directly linked yet perpendicularly prearranged composite systems. The synthesis was developed to allow facile tuning of the chromophore platform and to thus adjust its redox properties. X-ray analysis revealed a pronounced planarity of the chromophore in the case of the BDIs, which led to a remarkable close packing in the crystal of the simplest derivative. On the other hand, deviation from planarity was found for the diester-substituted bc-BDP benzocrown that exhibits a butterfly-like conformation in the crystal. Both families of dyes show charge- or electron-transfer-type fluorescence-quenching characteristics in polar solvents when equipped with a strong donor in the meso-position of the core. These processes can be utilized for signaling purposes if an appropriate receptor is introduced. Further modification of the chromophore can invoke such a guest-responsive intramolecular quenching process, also for receptor groups of low electron density, for example, benzocrowns. In addition to the design of various prototype molecules, a promising fluoroionophore for Na+ was obtained that absorbs and emits in the 650 nm region and shows a strong fluorescence enhancement upon analyte binding. Furthermore, investigation of the remarkable solvatokinetic fluorescence properties of the butterfly-like bc-BDP derivatives suggested that a second intrinsic nonradiative deactivation channel can play a role in the photophysics of boron-dipyrromethene dyes. KW - Charge KW - Transfer KW - Dyes/pigments KW - Electron transfer KW - Fluorescence KW - Farbstoffe KW - Chemosensoren KW - NIR-Bereich KW - Photophysik KW - Röntgenstrukturanalyse PY - 2004 DO - https://doi.org/10.1002/chem.200400173 SN - 0947-6539 SN - 1521-3765 VL - 10 SP - 4853 EP - 4871 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-4125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shen, Z. A1 - Uno, H. A1 - Ono, N. A1 - Rurack, Knut A1 - Daub, J. T1 - Synthesis, electrochemical and spectroscopic studies on a new class of boron dipyrromethene based fluoroionophores PY - 2002 VL - 18 SP - 100 EP - 102 (Suppl. A) PB - Elsevier CY - Amsterdam AN - OPUS4-2082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gant, Simon A1 - Chang, Joseph A1 - Hetherington, Rory A1 - Hanna, Steven A1 - Tickle, Gemma A1 - Spicer, Tom A1 - McMasters, Sun A1 - Fox, Shannon A1 - Meris, Ron A1 - Bradley, Scott A1 - Miner, Sean A1 - King, Matthew A1 - Simpson, Steven A1 - Mazzola, Thomas A1 - McGillivray, Alison A1 - Tucker, Harvey A1 - Björnham, Oscar A1 - Carissimo, Bertrand A1 - Fabbri, Luciano A1 - Wood, Maureen A1 - Habib, Abdel Karim A1 - Harper, Mike A1 - Hart, Frank A1 - Vik, Thomas A1 - Helgeland, Anders A1 - Howard, Joel A1 - Mauri, Lorenzo A1 - Mackie, Shona A1 - Mack, Andreas A1 - Lacome, Jean-Marc A1 - Puttick, Stephen A1 - Ibrahim, Adeel A1 - Miller, Derek A1 - Dharmavaram, Seshu A1 - Shen, Amy A1 - Cunningham, Alyssa A1 - Beverly, Desiree A1 - O’Neal, Daniel M. A1 - Verdier, Laurent A1 - Burkhart, Stéphane A1 - Dixon, Chris A1 - Nilsen, Sandra A1 - Bradley, Robert A1 - Skarsvåg, Hans L. A1 - Fyhn, Eirik H. A1 - Aasen, Ailo T1 - Pressure-Liquefied Ammonia Jet Dispersion: Multi-Model Intercomparison Using Desert Tortoise and FLADIS Field Data N2 - This paper presents the findings of an international model inter-comparison exercise that was undertaken in the period 2021-2024 to assess the performance of atmospheric dispersion models for simulating releases of pressure-liquefied ammonia. The exercise used data from ammonia field trials dating from the 1980s and 1990s: the Desert Tortoise and the FLADIS trials. Concentration data from two arcs of sensors in the Desert Tortoise trials and three arcs of sensors in the FLADIS trials were used. Twenty-one independent modelling teams from North America and Europe participated in the exercise and provided in total twenty-seven sets of results from a range of different models, including empirically-based nomograms, integral, Gaussian puff, Lagrangian particle, and Computational Fluid Dynamics (CFD) models. The work is novel in presenting the results from such a large cohort of models, examining specifically the dispersion behaviour of ammonia. This is particularly relevant at the current time, given the growing international interest in using ammonia as a clean energy vector and shipping fuel. The study found that the agreement between model predictions and measurements (as determined by performance measures such as geometric mean bias and geometric variance) varied between different models. At any downwind distance, the range in predicted plume arc-max concentrations spanned a range of up to one or two orders of magnitude about the measurements. Several modelling teams used the same models and, in most cases, their predictions differed. Given appropriate inputs, most models generally predicted concentrations that agreed with the data within commonly-used model acceptance criteria. There was no single class of model that provided superior predictions to others; predictions from several empirically-based nomograms, integral, Gaussian puff, Lagrangian particle, and CFD models were all in close agreement with the data (as defined by the model acceptance criteria). The findings of the exercise are being used to help plan a programme of future ammonia experiments in the USA, called the Jack Rabbit III trials. The results are also useful for assessing the performance of models that may be applied to assess risks at ammonia facilities, and for emergency planning and response. KW - Ammonia KW - Atmospheric dispersion KW - Validation KW - Jack rabbit PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646069 DO - https://doi.org/10.1016/j.aeaoa.2025.100389 SN - 2590-1621 VL - 28 SP - 1 EP - 76 PB - Elsevier Ltd. AN - OPUS4-64606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, R. A1 - Qian, M. A1 - Waske, Anja A1 - Shen, H. A1 - Zhang, X. T1 - Investigating the microstructure and magnetic properties of La-Fe-Si microwires during fabrication and heat treatment process N2 - In this study, the optimized fabrication and evolution of the microstructure and magnetic Transition behavior of the melt-extraction LaFe11.2Si1.8 microwires have been studied. After the optimization of extraction technique (heating power 22 KW, feeding rate 30-50 mm/s, rotation velocity 1700 r/min), the content of La Fe,Si)13 phase in the as-extracted microwires was 54 wt% due to the high solidification velocity, which was increased to 85 wt% via annealing at 1373 K for 20 min. The amount of La(Fe,Si)13 phase was increased and the composition of La(Fe,Si)13 phase became more homogenized through peritectic reaction and short-distance diffusion in the microwires during annealing process. The coexistence of the nanocrystalline and amorphous structures contributed to the broad magnetic Transition temperature range of the as-extracted and annealed microwires. The annealed microwires exhibited a second-order magnetic transformation behavior and showed a maximum magnetic entropy Change jDSMjmax of 6.2 J/kgK and working temperature interval of 36.0 K under a magnetic field of 20 kOe. KW - Magnetocaloric effect KW - Melt-extraction technique KW - La(Fe,Si)13 phase KW - Peritectic reaction KW - Short-distance diffusion PY - 2019 DO - https://doi.org/10.1016/j.jallcom.2019.04.196 SN - 0925-8388 SN - 1873-4669 VL - 794 SP - 153 EP - 162 PB - Elsevier B.V. AN - OPUS4-48095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liu, H. A1 - Song, W. A1 - Gröninger, Delia A1 - Zhang, L. A1 - Lu, Y. A1 - Chan, K. S. A1 - Zhou, Z. A1 - Rurack, Knut A1 - Shen, Z. T1 - Real-time monitoring of newly acidified organelles during autophagy enabled by reaction-based BODIPY dyes N2 - Real-time monitoring of newly acidified organelles during autophagy in living cells is highly desirable for a better understanding of intracellular degradative processes. Herein, we describe a reaction-based boron dipyrromethene (BODIPY) dye containing strongly electron-withdrawing diethyl 2-cyanoacrylate groups at the α-positions. The probe exhibits intense red fluorescence in acidic organelles or the acidified cytosol while negligible fluorescence in other regions of the cell. The underlying mechanism is a nucleophilic reaction at the central meso-carbon of the indacene core, resulting in the loss of π-conjugation entailed by dramatic spectroscopic changes of more than 200 nm between its colorless, non-fluorescent leuco-BODIPY form and its red and brightly emitting form. The reversible transformation between red fluorescent BODIPY and leuco-BODIPY along with negligible cytotoxicity qualifies such dyes for rapid and direct intracellular lysosome imaging and cytosolic acidosis detection simultaneously without any washing step, enabling the real-time monitoring of newly acidified organelles during autophagy. KW - Autophagy KW - BODIPY KW - Fluorescence KW - Lysosome KW - Real-time imaging PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498358 UR - https://www.nature.com/articles/s42003-019-0682-1 DO - https://doi.org/10.1038/s42003-019-0682-1 SN - 23993642 VL - 2 SP - 442 PB - Nature Research CY - London AN - OPUS4-49835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, H.-J. A1 - Mack, J. A1 - Wu, D. A1 - Xue, Z.-L. A1 - Descalzo López, Ana Belén A1 - Rurack, Knut A1 - Kobayashi, N. A1 - Shen, Z. T1 - Synthesis and properties of fused-ring-expanded porphyrins that were core-modified with group 16 heteroatoms N2 - The synthesis of a series of novel core-modified and fused-ring-expanded tetraphenylporphyrins is reported. Theoretical calculations and magnetic circular dichroism (MCD) and fluorescence spectroscopic measurements were used to analyze the effect of core modification with Group 16 oxygen, sulfur, selenium, and tellurium atoms on the optical properties and electronic structures of the porphyrins. Marked redshifts of the Q and B bands and accelerated intersystem-crossing rates were observed, thus making these compounds potentially suitable for use in a variety of applications. The scope for further fine-tuning of these optical properties based on additional structural modifications, such as the incorporation of fused benzene rings to form ABAB structures by using a thiophene precursor with a fused bicyclo[2.2.2]octadiene ring and the introduction of various substituents onto the meso-phenyl rings, is also examined. KW - Density functional calculations KW - Fluorescence KW - MCD spectroscopy KW - Porphyrinoids KW - Ring expansion PY - 2012 DO - https://doi.org/10.1002/chem.201200956 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 52 SP - 16844 EP - 16867 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, H.-J. A1 - Mack, J. A1 - Descalzo López, Ana Belén A1 - Shen, Z. A1 - Kobayashi, N. A1 - You, X.-Z. A1 - Rurack, Knut T1 - meso-Aryl phenanthroporphyrins: Synthesis and spectroscopic properties N2 - The successful synthesis of tetraphenyltetraphenanthroporphyrin (TPTPhenP; 5a) in 2006 under modified Rothemund–Lindsey conditions yielded a tetraphenyl porphyrinoid with a B band redshifted to an unprecedented 576 nm. Radially symmetric fused-ring expansion of tetraphenylporphyrin with phenanthrene moieties results in very deep saddling due to steric crowding and very marked redshifts of the Q and B (or Soret) porphyrinoid absorption bands. The extent to which the TPTPhenP structure can be further modified is explored, and the optical properties of TPTPhenPs are analyzed based on a perimeter model approach that makes use of time-dependent DFT calculations and magnetic circular dichroism spectroscopy and also based on a detailed analysis of the fluorescence emission. Attempts to introduce substituents at the ortho and meta positions of the meso-phenyl groups and to insert a central metal proved unsuccessful. The synthesis of a series of TPTPhenPs with strong electron-withdrawing (—CN, —NO2) and -donating (—CH3, —N(CH3)2) substituents at the para positions of the meso-phenyl rings is reported. Marked redshifts of the main spectral bands were consistently observed. The most pronounced spectral changes were observed with —N(CH3)2 groups (5i) due to a marked destabilization of the HOMO, which has large MO coefficients on the meso-carbon atoms. Protonation of 5i at both the ligand core and at the —N(CH3)2 groups resulted in unprecedented Q00 band absorption at wavelengths greater than 1200 nm. KW - Charge transfer KW - Circular dichroism KW - Dyes/pigments KW - Porphyrinoids KW - Protonation PY - 2011 DO - https://doi.org/10.1002/chem.201002596 SN - 0947-6539 SN - 1521-3765 VL - 17 IS - 32 SP - 8965 EP - 8983 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-24208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Xu, H.-J. A1 - Shen, Z. A1 - Rurack, Knut T1 - Red/Near-infrared Boron-Dipyrromethene Dyes as Strongly Emitting Fluorophores KW - BODIPY dyes KW - Near-infrared fluorophores KW - Fluorescent indicators KW - Charge transfer KW - Ring-fusion PY - 2008 DO - https://doi.org/10.1196/annals.1430.016 SN - 0077-8923 SN - 1749-6632 SN - 0094-8500 VL - 1130 SP - 164 EP - 171 PB - New York Academy of Sciences CY - New York, NY AN - OPUS4-17632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo, Ana B. A1 - Xu, H.-J. A1 - Shen, Z. A1 - Rurack, Knut T1 - Influence of the meso-substituent on strongly red emitting phenanthrene-fused boron–dipyrromethene (BODIPY) fluorophores with a propeller-like conformation N2 - Highly emissive phenanthrene-fused boron–dipyrromethene (PBDP) dyes have been spectroscopically characterized in a series of solvents. The influence of different substituents (-H, -I, -CN, -DMA or a 15C5-crown ether) in the para-position of a phenyl ring attached to the meso-position of the BODIPY core is discussed. This family of dyes has an intense emission at lambda > 630 nm, with fluorescence quantum yields between 0.7 and 1.0 in all solvents studied, except in the case of the dimethylamino-substituted derivative, PBDP-DMA, which undergoes excited-state intramolecular charge transfer (CT), leading to broadband dual fluorescence in highly polar solvents. Introduction of a weaker electron donor such as a benzocrown to the meso-position is not able to trigger a second (charge or electron transfer) process and, interestingly, heavy atom (iodine, PBDP-I derivative) substitution at that moiety does also not have a relevant influence on the photophysics, i.e., enhanced intersystem crossing was not observed. Electrochemical studies of PBDP-DMA complement the data reported and stress the fact that the decrease in fluorescence of PBDP-DMA in highly polar solvents is due to an excited-state CT process rather than to a photoinduced electron transfer (PET). KW - BODIPY dyes KW - Charge transfer KW - Fluorescence KW - Ring fusion PY - 2018 DO - https://doi.org/10.1016/j.jphotochem.2017.10.034 SN - 1010-6030 VL - 352 SP - 98 EP - 105 PB - Elsevier CY - Amsterdam AN - OPUS4-43100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo López, Ana Belén A1 - Xu, H.-J. A1 - Xue, Z.-L. A1 - Hoffmann, Katrin A1 - Shen, Z. A1 - Weller, Michael G. A1 - You, X.-Z. A1 - Rurack, Knut T1 - Phenanthrene-Fused Boron-Dipyrromethenes as Bright Long-Wavelength Fluorophores N2 - A new class of boron-dipyrromethene (BDP or BODIPY) dyes was obtained by phenanthrene fusion to the β-pyrrole positions, absorbing in the wavelength range of important laser sources. Despite a 'propeller-like' distorted structure in the crystalline state, the chromophore absorbs (log ε ≥ 5) and fluoresces (Φf ≥ 0.8) strongly and can be easily turned into a fluorescence light-up probe. Incorporation into latex beads produces bright and photostable single-dye and Förster Resonance Energy Transfer (FRET) particles for microscopy applications. KW - Fluoreszenz KW - Absorption KW - BODIPY-Farbstoffe KW - Ladungstransfer KW - NIR-Farbstoffe PY - 2008 DO - https://doi.org/10.1021/ol800271e SN - 1523-7060 SN - 1523-7052 VL - 10 IS - 8 SP - 1581 EP - 1584 PB - American Chemical Society CY - Washington, DC AN - OPUS4-17511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -