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151.
Vinylsubstituted boronates i.e. vinyldioxaborolane and vinyldioxaborinane react regioselectively with olefins in the presence of RuHCl(CO)(PCy3)2 with the formation of functionalized vinylboron derivatives. The reaction opens a new catalytic route for preparation of organoboranes. 相似文献
152.
The effects of oxidation or reduction of the platinum contact used in nitrate-selective electrodes without internal reference solutions were studied by using voltammetric curves. A correlation was found between the state of the platinum surface and the standard potential of the ion-selective electrode under potentiometric conditions. 相似文献
153.
Armada MP Losada J Zamora M Alonso B Cuadrado I Casado CM 《Bioelectrochemistry (Amsterdam, Netherlands)》2006,69(1):65-73
The electrochemical characterization of polymethylferrocenyl dendrimers deposited onto a platinum electrode and their applications as hydrogen peroxide and glucose sensor are described. The redox dendrimers consist of flexible poly(propileneimine) dendrimer cores functionalised with octamethylferrocenyl units. Amperometric biosensors for glucose were prepared by immobilization of glucose oxidase onto these modified electrodes. The influence of the dendrimer generation and the thickness of the dendrimer layer, the effect of the substrate concentration, and the interferences and reproducibility on the response of the sensors were investigated. 相似文献
154.
Magdalena Kowalska 《Hyperfine Interactions》2010,196(1-3):199-203
Since 2006 the ISOLTRAP mass spectrometer has provided high-precision masses of many short-lived nuclides located all across the nuclear chart with half-lives down to a few 10 ms. These nuclides range from the two-proton halo candidate 17Ne, via the neutron-rich magic 80Zn and 132Sn, up to 229Rn which was identified for the first time. The results show that ISOLTRAP is a versatile tool well suited to address physics topics such as nuclear structure, stellar nucleosynthesis, or the weak interaction. 相似文献
155.
Magdalena Pecul Christine Deillon Andreas J. Thorvaldsen Kenneth Ruud 《Journal of Raman spectroscopy : JRS》2010,41(10):1200-1210
Vibrational Raman optical activity (ROA) spectra have been measured for aqueous solutions of 4(R)‐hydroxyproline at three different pH values and are compared with theoretical results calculated for several conformations of anionic, cationic and zwitterionic 4(R)‐hydroxyproline using density functional theory (DFT) and the polarizable continuum model (PCM). The experimental ROA bands have been ascribed to the normal modes by comparison of the experimental and calculated vibrational frequencies and ROA intensities. Overall, using PCM for geometry optimization and force field calculations gives simulated Raman and ROA spectra that agree with the main features of the experimental spectra, whereas using PCM also in the calculations of optical tensors seems more problematic. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
156.
We consider the fractional Burgers' equation on RN with the critical dissipation term. We follow the parabolic De-Giorgi's method of Caffarelli and Vasseur and show existence of smooth solutions given any initial datum in L2(RN). 相似文献
157.
Marieta Nichifor Magdalena Cristina Stanciu Bogdan C. Simionescu 《Journal of Macromolecular Science: Physics》2013,52(5):983-993
The intermolecular hydrophobic association in diluted aqueous solutions of some cationic amphiphilic polysaccharides was investigated using fluorescence techniques. Dextran and dextran carrying N-alkyl-N,N-dimethyl-N(2-hydroxypropylene) ammonium chloride groups as side chains were single labeled with pyrene or naphthalene. The intensity of the pyrene excimer peak and the ratio I3/I1 determined from the fluorescence emission spectra of pyrene-labeled amphiphilic polymer increased with increasing polymer concentration and were higher than in the solution containing pyrene-labeled dextran. Emission spectra of diluted solution (0.008–0.2 g/dl) containing mixtures of pyrene and naphthalene single-labeled amphiphilic polymers proved the occurrence of a nonradiative energy transfer between labels at very a low polymer concentration (<10?2 g/dl). The energy transfer was not observed in mixtures of single-labeled unmodified dextran. All these results suggest that the intermolecular hydrophobic association of alkyl substituents takes place at a very low concentration of amphiphilic polymers. 相似文献
158.
Magdalena Piszczek 《Aequationes Mathematicae》2013,85(1-2):111-118
We prove that a set-valued function satisfying some functional inclusions admits, in appropriate conditions, a unique selection satisfying the corresponding functional equation. As a consequence we obtain the result on the Hyers–Ulam stability of that functional equation. 相似文献
159.
María Magdalena Añino Gabriela Merino Alberto Miyara Marisol Perassi Emiliano Ravera Gustavo Pita 《International Journal of Mathematical Education in Science & Technology》2013,44(3):378-395
This paper describes an action-research experience carried out with second year students at the School of Engineering of the National University of Entre Ríos, Argentina. Vector calculus students played an active role in their own learning process. They were required to present weekly reports, in both oral and written forms, on the topics studied, instead of merely sitting and watching as the teacher solved problems on the blackboard. The students were also asked to perform computer assignments, and their learning process was continuously monitored. Among many benefits, this methodology has allowed students and teachers to identify errors and misconceptions that might have gone unnoticed under a more passive approach. 相似文献
160.
In this paper we classify the complete rotational special Weingarten surfaces in ${\mathbb{S}^2 \times \mathbb{R}}$ and ${\mathbb{H}^2 \times \mathbb{R}}$ ; i.e. rotational surfaces in ${\mathbb{S}^2 \times \mathbb{R}}$ and ${\mathbb{H}^2 \times \mathbb{R}}$ whose mean curvature H and extrinsic curvature K e satisfy H = f(H 2 ? K e ), for some function ${f \in \mathcal{C}^1([0,+\infty))}$ such that f(0) = 0 and 4x(f′(x))2 < 1 for any x ≥ 0. Furthermore we show the existence of non-complete examples of such surfaces. 相似文献