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991.
H. Masenda S. Geburt K. Bharuth-Ram D. Naidoo H. P. Gunnlaugsson K. Johnston R. Mantovan T. E. Mølholt M. Ncube S. Shayestehaminzadeh H. P. Gislason G. Langouche S. Ólafsson C. Ronning ISOLDE Collaboration 《Hyperfine Interactions》2016,237(1):40
Emission Mössbauer Spectroscopy following the implantation of radioactive precursor isotope 57Mn+ (T 1/2= 1.5 min) into ZnO single crystals at ISOLDE/CERN shows that a large fraction of 57Fe atoms produced in the 57Mn beta decay is created as paramagnetic Fe3+ with relatively long spin-lattice relaxation times. Here we report on ZnO pre-implanted with 56Fe to fluences of 2×1013, 5×10 13 and 8 × 1013 ions/cm2 in order to investigate the dependence of the paramagnetic relaxation rate of Fe3+ on fluence. The spectra are dominated by magnetic features displaying paramagnetic relaxation effects. The extracted spin-lattice relaxation rates show a slight increase with increasing ion fluence at corresponding temperatures and the area fraction of Fe3+ at room temperature reaches a maximum contribution of 80(3)% in the studied fluence range. 相似文献
992.
Henriette de Loor Ruben Poesen Wout De Leger Wim Dehaen Patrick Augustijns Pieter Evenepoel Björn Meijers 《Analytica chimica acta》2016
Chronic kidney disease (CKD) is associated with an increased risk of mortality and cardiovascular disease, which is, at least partly, mediated by the accumulation of so-called uremic retention solutes. Although there has been an increasing interest in the behavior of these solutes, derived from both the endogenous and colonic microbial metabolism, methods to simultaneously and accurately measure a broad panel of relevant uremic retention solutes remain scarce. 相似文献
993.
The FitzHugh–Nagumo equations are known to admit fast traveling pulses that have monotone tails and arise as the concatenation of Nagumo fronts and backs in an appropriate singular limit, where a parameter \(\varepsilon \) goes to zero. These pulses are known to be nonlinearly stable with respect to the underlying PDE. Recently, the existence of fast pulses with oscillatory tails was proved for the FitzHugh–Nagumo equations. In this paper, we prove that the fast pulses with oscillatory tails are also nonlinearly stable. Similar to the case of monotone tails, stability is decided by the location of a nontrivial eigenvalue near the origin of the PDE linearization about the traveling pulse. We prove that this real eigenvalue is always negative. However, the expression that governs the sign of this eigenvalue for oscillatory pulses differs from that for monotone pulses, and we show indeed that the nontrivial eigenvalue in the monotone case scales with \(\varepsilon \), while the relevant scaling in the oscillatory case is \(\varepsilon ^{2/3}\). 相似文献
994.
Inside Back Cover: Self‐Assembly of Measles Virus Nucleocapsid‐like Particles: Kinetics and RNA Sequence Dependence (Angew. Chem. Int. Ed. 32/2016) 下载免费PDF全文
995.
Dr. Lars Michael Skjolding Dr. Sara Nørgaard Sørensen Dr. Nanna Bloch Hartmann M. Sc. Rune Hjorth Dr. Steffen Foss Hansen Dr. Anders Baun 《Angewandte Chemie (International ed. in English)》2016,55(49):15224-15239
The number of products on the market containing engineered nanoparticles (ENPs) has increased significantly, and concerns have been raised regarding their ecotoxicological effects. Environmental safety assessments as well as relevant and reliable ecotoxicological data are required for the safe and sustainable use of ENPs. Although the number of publications on the ecotoxicological effects and uptake of ENPs is rapidly expanding, the applicability of the reported data for hazard assessment is questionable. A major knowledge gap is whether nanoparticle effects occur when test organisms are exposed to ENPs in aquatic test systems. Filling this gap is not straightforward, because of the broad range of ENPs and the different behavior of ENPs compared to “ordinary” (dissolved) chemicals in the ecotoxicity test systems. The risk of generating false negatives, and false positives, in the currently used tests is high, and in most cases difficult to assess. This Review outlines some of the pitfalls in the aquatic toxicity testing of ENPs which may lead to misinterpretation of test results. Response types are also proposed to reveal potential nanoparticle effects in the aquatic test organisms. 相似文献
996.
Catalytic Water Oxidation by Ruthenium Complexes Containing Negatively Charged Ligand Frameworks 下载免费PDF全文
Artificial photosynthesis represents an attractive way of converting solar energy into storable chemical energy. The H2O oxidation half‐reaction, which is essential for producing the necessary reduction equivalents, is an energy‐demanding transformation associated with a high kinetic barrier. Herein we present a couple of efficient Ru‐based catalysts capable of mediating this four‐proton‐four‐electron oxidation. We have focused on the incorporation of negatively charged ligands, such as carboxylate, phenol, and imidazole, into the catalysts to decrease the redox potentials. This account describes our work in designing Ru catalysts based on this idea. The presence of the negatively charged ligands is crucial for stabilizing the metal centers, allowing for light‐driven H2O oxidation. Mechanistic details associated with the designed catalysts are also presented.
997.
Iiris Attorps Kjell Björk Mirko Radic 《International Journal of Mathematical Education in Science & Technology》2016,47(1):45-57
In this paper, we report a teaching experiment regarding the theory of polynomial approximations at the university mathematics teaching in Sweden. The experiment was designed by applying Variation theory and by using the free dynamic mathematics software GeoGebra. The aim of this study was to investigate if the technology-assisted teaching of Taylor polynomials compared with traditional way of work at the university level can support the teaching and learning of mathematical concepts and ideas. An engineering student group (n = 19) was taught Taylor polynomials with the assistance of GeoGebra while a control group (n = 18) was taught in a traditional way. The data were gathered by video recording of the lectures, by doing a post-test concerning Taylor polynomials in both groups and by giving one question regarding Taylor polynomials at the final exam for the course in Real Analysis in one variable. In the analysis of the lectures, we found Variation theory combined with GeoGebra to be a potentially powerful tool for revealing some critical aspects of Taylor Polynomials. Furthermore, the research results indicated that applying Variation theory, when planning the technology-assisted teaching, supported and enriched students’ learning opportunities in the study group compared with the control group. 相似文献
998.
999.
Experimental evidence for an effect of molecular conformation on inner-shell ionization energies has been observed for the first time. Examples are seen in the carbon 1s spectra of butyronitrile, 1-fluoropropane, and propanal, and other similar molecules. At room temperature these exist in two different conformations, with different distances and, hence, different Coulombic interactions between the negatively charged electronegative group and the methyl carbon. The experimental results are in accord with theoretical predictions with respect to both ionization energies and populations of the different conformers. 相似文献
1000.