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21.
Pieter Bouckenooge Oliver Bauer Kathrin Eckhard Herman Terryn 《Surface and interface analysis : SIA》2020,52(4):174-184
In this paper, the behaviour of the industrial applied Ti/Zr conversion coating (CC) pretreatment on rolled automotive aluminium samples (AA5182) is analysed. Due to its nanometre lateral and depth resolution, Auger electron spectroscopy (AES) is used to analyse the CC distribution at surface cathodic intermetallic particles. As a result of its high surface sensitivity, the AES technique is very susceptible to differences in the top contamination layer thickness. It is demonstrated that AES point measurements performed on aluminium model samples coated with 1.5 and 3 nm of Ti (oxide) layer cannot differentiate the two-layer thicknesses if a difference in the top contamination thickness is not taken into account. A data analysis methodology is introduced, based on the ratio of normalized peak areas (enrichment ratios), to eliminate the effect of the contamination layer thickness. The experimental validation of the methodology is performed on the model samples, demonstrating errors of 2% on the enrichment ratios on similar samples with different contamination layer thicknesses, while the conventional spectra quantification results in errors of 49%. The methodology is also theoretically substantiated within certain constraints. By the use of the AES methodology, an enriched Ti and Zr deposition is confirmed at the cathodic intermetallic particles at the surface of the industrial no-rinse CC sprayed automotive aluminium sheet samples. 相似文献
22.
Dr. Christoph Ludwig Teske Dr. Anna-Lena Hansen Prof. Dr. Richard Weihrich Prof. Dr. Lorenz Kienle Marius Kamp Kasper Pieter van der Zwan Prof. Dr. Jürgen Senker Dr. Carsten Dosche Prof. Dr. Gunther Wittstock Prof. Dr. Wolfgang Bensch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(27):6763-6772
A new preparation route is developed for the synthesis of needle-like crystals of [Au(S2CNH2)2]SCN, which avoids disproportionation of the AuI salt used as a starting material. In the crystal structure, the two crystallographically independent AuIII centers are in a square-planar environment of two S2CNH2 ligands. The Hirshfeld surface analysis reveals the presence of noncovalent intermolecular S⋅⋅⋅S interactions, which are essential for the spatial arrangement of the molecules. Density functional theory (DFT) calculations including dispersion and damping corrections result in a unit cell volume very close to the value determined experimentally. Thermal decomposition in an inert atmosphere generates black needles with lengths of up to 500 μm. X-ray powder diffraction and pair distribution function analyses demonstrate that the needles are composed of nanosized crystals with a volume-weighted average domain size of 20(1) nm. According to results of X-ray photoemission experiments, the black needles are covered by a nitrogen-rich carbon nitride with composition near (CN)2N. 13C solid-state NMR investigations indicate that two different carbon species are present, with signals corresponding well to heptazine units as in melon and triazine units as in poly(triazin imide) type compounds. Scanning transmission electron microscopy tomography evidences that the needles are composed of slightly elongated nanoparticles. 相似文献
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Journal of Nonlinear Science - We compare one-dimensional representations for the isotopy stable dynamics of homeomorphisms in two dimensions. We consider the skeleton graph representative, which... 相似文献
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The 15th International Conference on X-ray Absorption Fine Structure (XAFS15) was held at the Pullman Beijing West Wanda Hotel in Beijing, China, on July 22–28, 2012. The conference was chaired by Ziyu Wu (Chinese Academy of Sciences). In conjunction with XAFS15, the workshop “XAFS theory and nano particles” was held July 18–20, 2012, in Chiba, Japan, and chaired by T. Fujikawa. 相似文献
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Christopher M. Rath Jane Y. Yang Theodore Alexandrov Pieter C. Dorrestein 《Journal of the American Society for Mass Spectrometry》2013,24(8):1167-1176
Atmospheric ionization methods are ideally suited for prolonged MS/MS analysis. Data-independent MS/MS is a complementary technique for analysis of biological samples as compared to data-dependent analysis. Here, we pair data-independent MS/MS with the ambient ionization method nanospray desorption electrospray ionization (nanoDESI) for untargeted analysis of bacterial metabolites. Proof-of-principle data and analysis are illustrated by sampling Bacillus subtilis and Pseudomonas aeruginosa directly from Petri dishes. We found that this technique enables facile comparisons between strains via MS and MS/MS plots which can be translated to chemically informative molecular maps through MS/MS networking. The development of novel techniques to characterize microbial metabolites allows rapid and efficient analysis of metabolic exchange factors. This is motivated by our desire to develop novel techniques to explore the role of interspecies interactions in the environment, health, and disease. This is a contribution to honor Professor Catherine C. Fenselau in receiving the prestigious ASMS Award for a Distinguished Contribution in Mass Spectrometry for her pioneering work on microbial mass spectrometry. Figure
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29.
Pieter Van Renterghem Pierre-Edouard Sottas Martial Saugy Peter Van Eenoo 《Analytica chimica acta》2013
Due to their performance enhancing properties, use of anabolic steroids (e.g. testosterone, nandrolone, etc.) is banned in elite sports. Therefore, doping control laboratories accredited by the World Anti-Doping Agency (WADA) screen among others for these prohibited substances in urine. It is particularly challenging to detect misuse with naturally occurring anabolic steroids such as testosterone (T), which is a popular ergogenic agent in sports and society. 相似文献
30.
Sustainable Three‐Component Synthesis of Isothioureas from Isocyanides,Thiosulfonates, and Amines 下载免费PDF全文
Pieter Mampuys Dr. Yanping Zhu Dr. Tjøstil Vlaar Dr. Eelco Ruijter Prof. Dr. Romano V. A. Orru Prof. Dr. Bert U. W. Maes 《Angewandte Chemie (International ed. in English)》2014,53(47):12849-12854
Multiple applications of isothioureas as fine chemicals (or their precursors) are known, but a general sustainable method for their synthesis was hitherto unavailable. We report a novel general approach towards S‐alkyl and S‐aryl isothioureas through a copper(I)‐catalyzed three‐component reaction between amines, isocyanides, and thiosulfonates. The formal synthesis of a superpotent sweetener further illustrates the applicability of our method. 相似文献