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41.
Hidde H. Brongersma Thomas Grehl Niels C.W. Kuijpers Emma R. Schofield Hendrik R.J. ter Veen 《Vacuum》2010,84(8):1005-1007
Low-Energy Ion Scattering (LEIS or ISS) is used to selectively analyze the atomic composition of the outer atomic layer of surfaces. In addition, the spectrum gives (non-destructively) the in-depth distribution. Using a double toroidal energy analyzer with parallel energy detection and time-of-flight filtering a high sensitivity and mass resolution of LEIS is achieved. This is demonstrated for a highly dispersed catalyst of Pt/Au on γ-alumina. The improved depth resolution is illustrated for self-assembled monolayers of alkanethiols (12-20 carbon atoms) on gold. Even for these low Z carbon atoms a clear shift of 8 eV/carbon atom is observed (using 1.5 keV 4He+ ion scattering). This opens many new possibilities for studies of ultra-thin diffusion barriers, high-k dielectrics and biosensors. 相似文献
42.
Rudy Van Cauwenbergh Peter Hendrix H. Robberecht Hendrik Deelstra 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1999,210(2):153-155
For the first time, daily dietary lithium intake for adults in Belgium has been evaluated by duplicate portion sampling, the heating of the samples in a microwave oven and atomic absorption spectrometric determination of the element. The mean intake value for adults (8.6±4.6 μg/day) is very low compared to the scarce literature data. Since the lithium requirement of humans and animals is still unknown, no comparison could be made with RDA values. 相似文献
43.
Daan Fierens Jan Ramon Maurice Bruynooghe Hendrik Blockeel 《Annals of Mathematics and Artificial Intelligence》2008,54(1-3):99-133
We discuss how to learn non-recursive directed probabilistic logical models from relational data. This problem has been tackled before by upgrading the structure-search algorithm initially proposed for Bayesian networks. In this paper we show how to upgrade another algorithm for learning Bayesian networks, namely ordering-search. For Bayesian networks, ordering-search was found to work better than structure-search. It is non-obvious that these results carry over to the relational case, however, since there ordering-search needs to be implemented quite differently. Hence, we perform an experimental comparison of these upgraded algorithms on four relational domains. We conclude that also in the relational case ordering-search is competitive with structure-search in terms of quality of the learned models, while ordering-search is significantly faster. 相似文献
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46.
Luc Knockaert Hendrik Rogier Daniël De Zutter 《AEUE-International Journal of Electronics and Communications》2005,59(4):1802
We propose to find the propagation constants of modes in layered media by means of signal identification methods. To this effect we employ Cauchy's theorem, conformal mapping and Fast Fourier Transform (FFT) techniques to generate relevant Hankel moments, afterwards to be processed with selected signal identification algorithms. The method, terminated by a few Newton steps, provides a batch of highly accurate roots in appropriate disks or half-disks. 相似文献
47.
Sousa F Mandal S Garrovo C Astolfo A Bonifacio A Latawiec D Menk RH Arfelli F Huewel S Legname G Galla HJ Krol S 《Nanoscale》2010,2(12):2826-2834
In the present study, the in vivo distribution of polyelectrolyte multilayer coated gold nanoparticles is shown, starting from the living animal down to cellular level. The coating was designed with functional moieties to serve as a potential nano drug for prion disease. With near infrared time-domain imaging we followed the biodistribution in mice up to 7 days after intravenous injection of the nanoparticles. The peak concentration in the head of mice was detected between 19 and 24 h. The precise particle distribution in the brain was studied ex vivo by X-ray microtomography, confocal laser and fluorescence microscopy. We found that the particles mainly accumulate in the hippocampus, thalamus, hypothalamus, and the cerebral cortex. 相似文献
48.
Ernst Hofmann Hendrik C. Kuhlmann 《International Journal of Heat and Mass Transfer》2012,55(25-26):7686-7697
The coupled heat- and mass-transfer of the absorbing falling film is considered in the flat-film approximation. We study the influence of the operating conditions on the absorption efficiency in a fully non-dimensional framework and find an optimal Reynolds number, which can be interpreted as an optimal film thickness. We also test various thermal wall boundary conditions to select the best approximation compared to a realistic test case. 相似文献
49.
Dr. Laura Drummond Parab J. Haque Dr. Binbin Gu Julia S. Jung Dr. Hendrik Schewe Prof. Dr. Jeroen S. Dickschat Dr. Markus Buchhaupt 《Chembiochem : a European journal of chemical biology》2022,23(14):e202200091
The natural substance class of terpenoids covers an extremely wide range of different structures, although their building block repertoire is limited to the C5 compounds DMAPP and IPP. This study aims at the characterization of methyltransferases (MTases) that modify these terpene precursors and the demonstration of their suitability for biotechnological purposes. All seven enzymes tested accepted IPP as substrate and altogether five C6 compounds and six C7 compounds were formed within the reactions. A high selectivity for the deprotonation site as well as high stereoselectivity could be observed for most of the biocatalysts. Only the enzyme from Micromonospora humi also accepted DMAPP as substrate, converting it into (2R)-2-methyl-IPP in vitro. In vivo studies demonstrated the production of a C8 compound and a hydride shift step within the MTase-catalyzed reaction. Our study presents IPP/DMAPP MTases with very different catalytic properties, which provide biosynthetic access to many novel terpene-derived structures. 相似文献
50.
Stumpo Vittorio Sebök Martina van Niftrik Christiaan Hendrik Bas Seystahl Katharina Hainc Nicolin Kulcsar Zsolt Weller Michael Regli Luca Fierstra Jorn 《Magma (New York, N.Y.)》2022,35(1):29-44
Magnetic Resonance Materials in Physics, Biology and Medicine - Innovative physiologic MRI development focuses on depiction of heterogenous vascular and metabolic features in glioblastoma. For this... 相似文献