TY - JOUR A1 - Tan, M. A1 - Monks, Melissa-Jane A1 - Huang, D. A1 - Meng, Y. A1 - Chen, X. A1 - Zhou, Y A1 - Lom, S.-F. A1 - Würth, Christian A1 - Resch-Genger, Ute A1 - Chen, G. T1 - Efficient sub-15 nm cubic-phase core/Shell upconversion nanoparticles as reporters for ensemble and single particle studies† N2 - Single particle imaging of upconversion nanoparticles (UCNPs) has typically been realized using hexagonal (β) phase lanthanide-doped sodium yttrium fluoride (NaYF4) materials, the upconversion luminescence (UCL) of which saturates at power densities (P) of several hundred W cm−2 under 980 nm nearinfrared (NIR) excitation. Cubic (α) phase UCNPs have been mostly neglected because of their commonly observed lower UCL efficiency at comparable P in ensemble level studies. Here, we describe a set of sub-15 nm ytterbium-enriched α-NaYbF4:Er3+@CaF2 core/shell UCNPs doped with varying Er3+ concentrations (5–25%), studied over a wide P range of ∼8–105 W cm−2, which emit intense UCL even at a low P of 10 W cm−2 and also saturate at relatively low P. The highest upconversion quantum yield (ΦUC) and the highest particle brightness were obtained for an Er3+ dopant concentration of 12%, reaching the highest ΦUC of 0.77% at a saturation power density (Psat) of 110 W cm−2. These 12%Er3+-doped core/shell UCNPs were also the brightest UCNPs among this series under microscopic conditions at high P of ∼102–105 W cm−2 as demonstrated by imaging studies at the single particle level. Our results underline the potential applicability of the described sub-15 nm cubic-phase core/shell UCNPs for ensemble- and single particle- level bioimaging. KW - Nano KW - Nanomaterial KW - Upconversion nanoparticle KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - Surface chemistry KW - Single particle KW - Brightness PY - 2020 DO - https://doi.org/10.1039/d0nr02172e VL - 12 IS - 19 SP - 10592 EP - 10599 PB - Nanoscale AN - OPUS4-50908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nelson, G. A1 - Boehm, U. A1 - Bagley, S. A1 - Bajcsy, P. A1 - Bischof, J. A1 - Brown, C. M. A1 - Dauphin, A. A1 - Dobbie, I. M. A1 - Eriksson, J. E. A1 - Faklaris, O. A1 - Fernandez-Rodriguez, J. A1 - Ferrand, A. A1 - Gelman, L, A1 - Gheisari, A. A1 - Hartmann, H. A1 - Kukat, C. A1 - Laude, A. A1 - Mitkovski, M. A1 - Munck, S. A1 - North, A. J. A1 - Rasse, T. A1 - Resch-Genger, Ute A1 - Schuetz, L. C. A1 - Seitz, A. A1 - Strambio-De-Castillia, C. A1 - Swedlow, J. R. A1 - Alexopoulos, I. A1 - Aumayr, K. A1 - Avilov, S. A1 - Bakker, G.-J. A1 - Bammann, R. R. A1 - Bassi, A. A1 - Beckert, H. A1 - Beer, S. A1 - Belyaev, Y. A1 - Bierwagen, J. A1 - Birngruber, K. A. A1 - Bosch, M. A1 - Breitlow, J. A1 - Cameron, L. A. A1 - Chalfoun, J. A1 - Chambers, J. J. A1 - Chen, C.-L. A1 - Conde-Sousa, E. A1 - Corbett, A. D. A1 - Cordelieres, F. P. A1 - Del Nery, E. A1 - Dietzel, R. A1 - Eismann, F. A1 - Fazeli, E. A1 - Felscher, A. A1 - Fried, H. A1 - Gaudreault, N. A1 - Goh, W. I. A1 - Guilbert, T. A1 - Hadleigh, R. A1 - Hemmerich, P. A1 - Holst, G. A. A1 - Itano, M. S. A1 - Jaffe, C. B. A1 - Jambor, H. K. A1 - Jarvis, S. C. A1 - Keppler, A. A1 - Kirchenbuechler, D. A1 - Kirchner, M. A1 - Kobayashi, N. A1 - Krens, G. A1 - Kunis, S. A1 - Lacoste, J. A1 - Marcello, M. A1 - Martins, G. G. A1 - Metcalf, D. J. A1 - Mitchell, C. A. A1 - Moore, J. A1 - Mueller, T. A1 - Nelson, M. S. A1 - Ogg, S. A1 - Onami, S. A1 - Palmer, A. L. A1 - Paul-Gilloteaux, P. A1 - Pimentel, J. A. A1 - Plantard, L. A1 - Podder, S. A1 - Rexhepaj, E. A1 - Royon, A. A1 - Saari, M. A. A1 - Schapman, D. A1 - Schoonderwoert, V. A1 - Schroth-Diez, B. A1 - Schwartz, S. A1 - Shaw, M. A1 - Spitaler, M. A1 - Stoeckl, M. T. A1 - Sudar, D. A1 - Teillon, J. A1 - Terjung, S. A1 - Thuenauer, R. A1 - Wilms, C. D. A1 - Wright, G. D. A1 - Nitschke, R. T1 - QUAREP-LiMi: A community-driven initiative to establish guidelines for quality assessment and reproducibility for instruments and images in light microscopy N2 - A modern day light microscope has evolved from a tool devoted to making primarily empirical observations to what is now a sophisticated, quantitative device that is an integral part of both physical and life science research. Nowadays, microscopes are found in nearly every experimental laboratory. However, despite their prevalent use in capturing and quantifying scientific phenomena, neither a thorough understanding of the principles underlying quantitative imaging techniques nor appropriate knowledge of how to calibrate, operate and maintain microscopes can be taken for granted. This is clearly demonstrated by the well-documented and widespread difficulties that are routinely encountered in evaluating acquired data and reproducing scientific experiments. Indeed, studies have shown that more than 70% of researchers have tried and failed to repeat another scientist’s experiments, while more than half have even failed to reproduce their own experiments1. One factor behind the reproducibility crisis of experiments published in scientific journals is the frequent underreporting of imaging methods caused by a lack of awareness and/or a lack of knowledge of the applied technique2,3. Whereas quality control procedures for some methods used in biomedical research, such as genomics (e.g., DNA sequencing, RNA-seq) or cytometry, have been introduced (e.g. ENCODE4), this issue has not been tackled for optical microscopy instrumentation and images. Although many calibration standards and protocols have been published, there is a lack of awareness and agreement on common Standards and guidelines for quality assessment and reproducibility5. In April 2020, the QUality Assessment and REProducibility for instruments and images in Light Microscopy (QUAREP-LiMi) initiative6 was formed. This initiative comprises imaging scientists from academia and industry who share a common interest in achieving a better understanding of the performance and limitations of microscopes and improved quality control (QC) in light microscopy. The ultimate goal of the QUAREP-LiMi initiative is to establish a set of common QC standards, guidelines, metadata models7,8, and tools9,10, including detailed protocols, with the ultimate aim of improving reproducible advances in scientific research. This White Paper 1) summarizes the major obstacles identified in the field that motivated the launch of the QUAREP-LiMi initiative; 2) identifies the urgent need to address these obstacles in a grassroots manner, through a community of Stakeholders including, researchers, imaging scientists11, bioimage analysts, bioimage informatics developers, corporate partners, Funding agencies, standards organizations, scientific publishers, and observers of such; 3) outlines the current actions of the QUAREPLiMi initiative, and 4) proposes future steps that can be taken to improve the dissemination and acceptance of the proposed guidelines to manage QC. To summarize, the principal goal of the QUAREP-LiMi initiative is to improve the overall quality and reproducibility of light microscope image data by introducing broadly accepted standard practices and accurately captured image data metrics. KW - Fluorescence KW - Microscopy KW - Quality assurance KW - Comparability KW - Imaging KW - Standards KW - Reference materials KW - Reliability KW - Data KW - Reference data KW - Biology KW - Medicine KW - Life science PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530629 DO - https://doi.org/10.1111/jmi.13041 SN - 1365-2818 VL - 284 IS - 1 SP - 56 EP - 73 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-53062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reed, B. P. A1 - Cant, D.J.H. A1 - Spencer, J. A1 - Carmona-Carmona, A. J. A1 - Bushell, A. A1 - Herrara-Gómez, A. A1 - Kurokawa, A. A1 - Thissen, A. A1 - Thomas, A.G. A1 - Britton, A.J. A1 - Bernasik, A. A1 - Fuchs, A. A1 - Baddorf, A. P. A1 - Bock, B. A1 - Thellacker, B. A1 - Cheng, B. A1 - Castner, D.G. A1 - Morgan, D.J. A1 - Valley, D. A1 - Willneff, E.A. A1 - Smith, E.F. A1 - Nolot, E. A1 - Xie, F. A1 - Zorn, G. A1 - Smith, G.C. A1 - Yasukufu, H. A1 - Fenton, J. L. A1 - Chen, J. A1 - Counsell, J..D.P. A1 - Radnik, Jörg A1 - Gaskell, K.J. A1 - Artyushkova, K. A1 - Yang, L. A1 - Zhang, L. A1 - Eguchi, M. A1 - Walker, M. A1 - Hajdyla, M. A1 - Marzec, M.M. A1 - Linford, M.R. A1 - Kubota, N. A1 - Cartazar-Martínez, O. A1 - Dietrich, P. A1 - Satoh, R. A1 - Schroeder, S.L.M. A1 - Avval, T.G. A1 - Nagatomi, T. A1 - Fernandez, V. A1 - Lake, W. A1 - Azuma, Y. A1 - Yoshikawa, Y. A1 - Shard, A.G. T1 - Versailles Project on Advanced Materials and Standards interlaboratory study on intensity calibration for x-ray photoelectron spectroscopy instruments using low-density polyethylene N2 - We report the results of a Versailles Project on Advanced Materials and Standards interlaboratory study on the intensity scale calibration of x-ray photoelectron spectrometers using low-density polyethylene (LDPE) as an alternative material to gold, silver, and copper. An improved set of LDPE reference spectra, corrected for different instrument geometries using a quartz-monochromated Al Kα x-ray source, was developed using data provided by participants in this study. Using these new reference spectra, a transmission function was calculated for each dataset that participants provided. When compared to a similar calibration procedure using the NPL reference spectra for gold, the LDPE intensity calibration method achieves an absolute offset of ∼3.0% and a systematic deviation of ±6.5% on average across all participants. For spectra recorded at high pass energies (≥90 eV), values of absolute offset and systematic deviation are ∼5.8% and ±5.7%, respectively, whereas for spectra collected at lower pass energies (<90 eV), values of absolute offset and systematic deviation are ∼4.9% and ±8.8%, respectively; low pass energy spectra perform worse than the global average, in terms of systematic deviations, due to diminished count rates and signal-to-noise ratio. Differences in absolute offset are attributed to the surface roughness of the LDPE induced by sample preparation. We further assess the usability of LDPE as a secondary reference material and comment on its performance in the presence of issues such as variable dark noise, x-ray warm up times, inaccuracy at low count rates, and underlying spectrometer problems. In response to participant feedback and the results of the study, we provide an updated LDPE intensity calibration protocol to address the issues highlighted in the interlaboratory study. We also comment on the lack of implementation of a consistent and traceable intensity calibration method across the community of x-ray photoelectron spectroscopy (XPS) users and, therefore, propose a route to achieving this with the assistance of instrument manufacturers, metrology laboratories, and experts leading to an international standard for XPS intensity scale calibration. KW - X-ray photoelectron spectroscopy KW - Transmission function KW - Intensity scale calibration KW - Reference spectra KW - Low-density polyethylene (LDPE) PY - 2020 DO - https://doi.org/10.1116/6.0000577 VL - 38 IS - 6 SP - 063208 AN - OPUS4-51655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reed, B. P. A1 - Cant, D.J.H. A1 - Spencer, S.J. A1 - Carmona-Carmona, A. J. A1 - Bushell, A. A1 - Herrara-Gómez, A. A1 - Kurokawa, A. A1 - Thissen, A. A1 - Thomas, A.G. A1 - Britton, A.J. A1 - Bernasik, A. A1 - Fuchs, A. A1 - Baddorf, A.P. A1 - Bock, B. A1 - Thellacker, B. A1 - Cheng, B. A1 - Castner, D.G. A1 - Morgan, D.J. A1 - Valley, D. A1 - Willneff, E.A. A1 - Smith, E.P. A1 - Nolot, E. A1 - Xie, F. A1 - Zorn, G. A1 - Smith, G.C. A1 - Yasukufu, H. A1 - Fenton, J.L. A1 - Chen, J. A1 - Counsell, J.D.P. A1 - Radnik, Jörg A1 - Gaskell, K.J. A1 - Artyushkova, K. A1 - Yang, L. A1 - Zhang, L. A1 - Eguchi, M. A1 - Walker, M. A1 - Hajdyla, M. A1 - Marzec, M.M. A1 - Linford, M.R. A1 - Kubota, N. A1 - Cortazar-Martinez, O. A1 - Dietrich, P. A1 - Satoh, R. A1 - Schroeder, S.L.M. A1 - Avval, T.G. A1 - Nagatomi, T. A1 - Fernandez, V. A1 - Lake, W. A1 - Azuma, Y. A1 - Yoshikawa, Y. A1 - Compean-Gonzalez, C.L. A1 - Ceccone, G. A1 - Shard, A.G. T1 - ERRATUM: “Versailles project on advanced materials and standards interlaboratory study on intensity calibration for x-ray photoelectron spectroscopy instruments using low-density polyethylene” [J. Vac. Sci. Technol. A 38, 063208 (2020)] N2 - The lead authors failed to name two collaborators as co-authors. The authors listed should include: Miss Claudia L. Compean-Gonzalez (ORCID: 0000-0002-2367-8450) and Dr. Giacomo Ceccone (ORCID: 0000-0003-4637-0771). These co-authors participated in VAMAS project A27, provided data that were analyzed and presented in this publication (and supporting information), and reviewed the manuscript before submission. KW - X-ray photoelectron spectroscopy KW - Transmission function KW - Low-density polyethylene PY - 2021 DO - https://doi.org/10.1116/6.0000907 VL - 39 IS - 2 SP - 027001 PB - American Vacuum Society AN - OPUS4-52380 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seah, M.P. A1 - Spencer, S.J. A1 - Bensebaa, F. A1 - Vickridge, I. A1 - Danzebrink, H. A1 - Krumrey, M. A1 - Gross, Thomas A1 - Österle, Werner A1 - Wendler, E. A1 - Rheinländer, B. A1 - Azuma, Y. A1 - Kojima, I. A1 - Suzuki, N. A1 - Suzuki, M. A1 - Tanuma, S. A1 - Moon, D.W. A1 - Lee, H.J. A1 - Cho, H.M. A1 - Chen, H.Y. A1 - Wee, A. T. S. A1 - Osipowicz, T. A1 - Pan, J.S. A1 - Jordaan, W.A. A1 - Hauert, R. A1 - Klotz, U. A1 - van der Marel, C. A1 - Verheijen, M. A1 - Tamminga, Y. A1 - Jeynes, C. A1 - Bailey, P. A1 - Biswas, S. A1 - Falke, U. A1 - Nguyen, N.V. A1 - Chandler-Horowitz, D. A1 - Ehrstein, J.R. A1 - Muller, D. A1 - Dura, J.A. T1 - Critical review of the current status of thickness measurements for ultrathin SiO2 on Si - Part V: Results of a CCQM pilot study N2 - Results are reported from a pilot study under the Consultative Committee for Amount of Substance (CCQM) to compare measurements of and resolve any relevant measurement issues in, the amount of thermal SiO2 oxide on (100) and (111) orientation Si wafer substrates in the thickness range 1.5 - 8 nm. As a result of the invitation to participate in this activity, 45 sets of measurements have been made in different laboratories using 10 analytical methods: medium-energy ion scattering spectrometry (MEIS), nuclear reaction analysis (NRA), RBS, elastic backscattering spectrometry (EBS), XPS, SIMS, ellipsometry, grazing-incidence x-ray reflectrometry (GIXRR), neutron reflectometry and transmission electron microscopy (TEM). The measurements are made on separate sets of 10 carefully prepared samples, all of which have been characterised by a combination of ellipsometry and XPS using carefully established reference conditions and reference parameters. The results have been assessed against the National Physical Laboratory (NPL) data and all show excellent linearity. The remaining data sets correlate with the NPL data with average root-mean-square scatters of 0.15 nm, half being better than 0.1 nm and a few at or better than 0.05 nm. Each set of data allows a relative scaling constant and a zero thickness offset to be determined. Each method has an inherent zero thickness offset between 0 nm and 1 nm and it is these offsets, measured here for the first time, that have caused many problems in the past. There are three basic classes of offset: water and carbonadeous contamination equivalent to ~1 nm as seen by ellipsometry; adsorbed oxygen mainly from water at an equivalent thickness of 0.5 nm as seen by MEIS, NRA, RBS and possibly GIXRR; and no offset as seen by XPS using the Si 2p peaks. Each technique has a different uncertainty for the scaling constant and consistent results have been achieved. X-Ray photoelectron spectroscopy has large uncertainties for the scaling constant but a high precision and, critically, if used correctly, has zero offset. Thus, a combination of XPS and the other methods allows the XPS scaling constant to be determined with low uncertainty, traceable via the other methods. XPS laboratories returning results early were invited to test a new reference procedure. All showed very significant improvements. The reference attenuation lengths thus need scaling by 0.986 ± 0.009 (at an expansion factor of 2) deduced from the data for the other methods. Several other methods have small offsets and, to the extent that these can be shown to be constant or measurable, then these methods will also show low uncertainty. Recommendations are provided for parameters for XPS, MEIS, RBS and NRA to improve their accuracy. KW - Calibration KW - Ellipsometry KW - GIXRR KW - Interlaboratory study KW - MEIS KW - Neutron reflectometry KW - NRA KW - RBS KW - Silicon dioxide KW - SIMS KW - XPS PY - 2004 DO - https://doi.org/10.1002/sia.1909 SN - 0142-2421 SN - 1096-9918 VL - 36 IS - 9 SP - 1269 EP - 1303 PB - Wiley CY - Chichester AN - OPUS4-5549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Seah, M.P. A1 - Spencer, S.J. A1 - Bensebaa, F. A1 - Vickridge, I. A1 - Danzebrink, H. A1 - Krumrey, M. A1 - Gross, Thomas A1 - Österle, Werner A1 - Wendler, E. A1 - Rheinländer, B. A1 - Azuma, Y. A1 - Kojima, I. A1 - Suzuki, N. A1 - Suzuki, M. A1 - Tanuma, S. A1 - Moon, D.W. A1 - Lee, H.J. A1 - Cho, H.M. A1 - Chen, H.Y. A1 - Wee, A. T. S. A1 - Osipowicz, T. A1 - Pan, J.S. A1 - Jordaan, W.A. A1 - Hauert, R. A1 - Klotz, U. A1 - van der Marel, C. A1 - Verheijen, M. A1 - Tamminga, Y. A1 - Jeynes, C. A1 - Bailey, P. A1 - Biswas, S. A1 - Falke, U. A1 - Nguyen, N.V. A1 - Chandler-Horowitz, D. A1 - Ehrstein, J.R. A1 - Muller, D. A1 - Dura, J.A. T1 - Ultra-thin SiO2 on Si, Part V: Results of a CCQM Pilot Study of Thickness Measurements KW - SiO2 KW - Thin films KW - Thickness KW - XPS KW - Ellipsometry KW - TEM PY - 2003 SN - 1473-2734 SP - 57 pages AN - OPUS4-4118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lin, R. A1 - Li, X. A1 - Krajnc, A. A1 - Li, Z. A1 - Li, M. A1 - Wang, W. A1 - Zhuang, L. A1 - Smart, S. A1 - Zhu, Z. A1 - Appadoo, D. A1 - Harmer, J. R. A1 - Wang, Z. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Beyer, S. A1 - Wang, L. A1 - Mali, G. A1 - Bennett, T. D. A1 - Chen, V. A1 - Hou, J. T1 - Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal–Organic Framework Glasses for the Oxygen Evolution Reaction N2 - The melting behaviour of metal–organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through meltquenching of the cobalt-based zeolitic imidazolate Framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62-(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co–Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device Assembly KW - Electrodes KW - MOF KW - OER KW - XANES KW - XAS KW - Bimetallic frameworks PY - 2022 DO - https://doi.org/10.1002/anie.202112880 VL - 61 IS - 4 SP - e202112880 PB - Wiley AN - OPUS4-54018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Duewer, D.L. A1 - May, W.E. A1 - Parris, R.M. A1 - Schantz, M.M. A1 - Wise, S. A. A1 - Piechotta, Christian A1 - Philipp, Rosemarie A1 - Win, Tin A1 - Avila, M. A1 - Pérez Urquiza, M. A1 - Ulberth, F. A1 - Kim, B. A1 - Ishikawa, K. A1 - Chen, D. A1 - Krylov, A.I. A1 - Kustidov, Y.A. A1 - Lopushanskaya, E.M. T1 - Final report on CCQM-K38: Determination of PAHs in solution PY - 2009 DO - https://doi.org/10.1088/0026-1394/46/1A/08003 SN - 0026-1394 SN - 1681-7575 VL - 46 IS - 08003 SP - 1 EP - 13 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-20029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schumacher, Gerhard A1 - Chen, S. H. A1 - Wahi, R. P. A1 - Mukherji, D. A1 - Frohberg, G. T1 - Deformation Substructures in a Near Gamma-TiAl Alloy With Duplex Microstructure KW - Titanium Aluminides KW - Stacking faults KW - Faulted dipoles KW - Lattice parameters PY - 2000 SN - 0924-0136 SN - 1873-4774 SP - 1(?) EP - 6(?) PB - Elsevier CY - Amsterdam AN - OPUS4-950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Autrique, D. A1 - Gornushkin, Igor B. A1 - Alexiades, V. A1 - Chen, Z. A1 - Bogaerts, A. A1 - Rethfeld, B. T1 - Revisiting the interplay between ablation, collisional, and radiative processes during ns-laser ablation N2 - A study of ns-laser ablation is presented, which focuses on the transient behavior of the physical processes that act in and above a copper sample. A dimensionless multiphase collisional radiative model describes the interplay between the ablation, collisional, and radiative mechanisms. Calculations are done for a 6 ns-Nd:YAG laser pulse operating at 532 nm and fluences up to 15 J/cm². Temporal intensity profiles as well as transmissivities are in good agreement with experimental results. It is found that volumetric ablation mechanisms and photo-processes both play an essential role in the onset of ns-laser induced breakdown. PY - 2013 DO - https://doi.org/10.1063/1.4826505 SN - 0003-6951 SN - 1077-3118 VL - 103 IS - 174102 SP - 1 EP - 5 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-30434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lee, C. A1 - Inutan, E. D. A1 - Chen, J. L. A1 - Mukeku, M. M. A1 - Weidner, Steffen A1 - Trimpin, S. A1 - Ni, C.-K. T1 - Toward understanding the ionization mechanism of matrix‐assisted ionization using mass spectrometry experiment and theory N2 - Matrix‐assisted ionization (MAI) mass spectrometry does not require voltages, a laser beam, or added heat to initiate ionization, but it is strongly dependent on the choice of matrix and the vacuum conditions. High charge state distributions of nonvolatile analyte ions produced by MAI suggest that the ionization mechanism may be similar to that of electrospray ionization (ESI), but different from matrix‐assisted laser desorption/ionization (MALDI). While significant information is available for MAI using mass spectrometers operating at atmospheric and intermediate pressure, little is known about the mechanism at high vacuum. Eleven MAI matrices were studied on a high‐vacuum time‐of‐flight (TOF) mass spectrometer using a 266 nm pulsed laser beam under otherwise typical MALDI conditions. Detailed comparisons with the commonly used MALDI matrices and theoretical prediction were made for 3‐nitrobenzonitrile (3‐NBN), which is the only MAI matrix that works well in high vacuum when irradiated with a laser. Screening of MAI matrices with good absorption at 266 nm but with various degrees of volatility and laser energies suggests that volatility and absorption at the laser wavelength may be necessary, but not sufficient, criteria to explain the formation of multiply charged analyte ions. 3‐NBN produces intact, highly charged ions of nonvolatile analytes in high‐vacuum TOF with the use of a laser, demonstrating that ESI‐like ions can be produced in high vacuum. Theoretical calculations and mass spectra suggest that thermally induced proton transfer, which is the major ionization mechanism in MALDI, is not important with the 3‐NBN matrix at 266 nm laser wavelength. 3‐NBN:analyte crystal morphology is, however, important in ion generation in high vacuum. The 3‐NBN MAI matrix produces intact, highly charged ions of nonvolatile compounds in high‐vacuum TOF mass spectrometers with the aid of ablation and/or heating by laser irradiation, and shows a different ionization mechanism from that of typical MALDI matrices. KW - Ionization KW - MALDI-TOF MS KW - Mechanism PY - 2021 DO - https://doi.org/10.1002/rcm.8382 VL - 35 IS - 51 SP - e8382 PB - John Wiley & Sons AN - OPUS4-49209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chen, Cong A1 - Delorme, F. A1 - Schoenstein, F. A1 - Zaghrioui, M. A1 - Flahaut, D. A1 - Allouche, J. A1 - Giovannelli, F. T1 - Synthesis, sintering, and thermoelectric properties of Co1-xMxO (M = Na, 0 ≤ x ≤ 0.07; M = Ag, 0 ≤ x ≤ 0.05) N2 - The structural and thermoelectric properties of Na- and Ag-substituted CoO dense ceramics have been investigated. X-ray diffraction shows that pure phase and Ag/CoO composites have been obtained for Na-doped and Ag-doped CoO, respectively. Raman spectroscopy shows an effect of Na dopants on the lattice disorder of CoO. The chemical composition, element distribution, and valence states of the samples have been characterized by Auger electron microscopy and X-ray photoelectron spectroscopy. Substitution of Co by 5 at. % Na enhances the power factor to 250 μWm−1 K-2 at 1000 K, similar to that of Ca3Co4O9. The corresponding thermal conductivity is also reduced to 3.55 W.m−1 K−1 at 1000 K. Consequently, Co0.95Na0.05O exhibits the best thermoelectric figure of merit (ZT), which is 0.07 at 1000 K. On the other hand, the substitution of Ag into CoO leads to the formation of CoO/Ag composites and deteriorates ZT values. KW - Thermoelectrics KW - CoO KW - Substitution KW - Spark plasma sintering KW - XPS PY - 2019 DO - https://doi.org/10.1016/j.jeurceramsoc.2018.10.013 SN - 0955-2219 SN - 1873-619X VL - 39 IS - 2–3 SP - 346 EP - 351 PB - Elsevier Ltd. AN - OPUS4-46453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -