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51.
Broad Gaussian line shapes are observed in scanning tunneling spectroscopy of single, localized electronic states induced by Cl vacancies in ultrathin NaCl films on Cu surfaces. Using a simple inelastic resonance tunneling model, we show that the observed broad line shapes are caused by a strong coupling between the localized state and the optical phonons in the film. The parameters for the model are obtained from density functional calculations, in which the occupation of the vacancy state temporarily taking place in the experiment has also been accounted for. 相似文献
52.
Florian?Nettesheim Claus?B.?Müller Ulf?Olsson Walter?RichteringEmail author 《Colloid and polymer science》2004,282(8):918-926
We report on the shear induced transition from the L3- to the L-phase studied by means of flow birefringence using the system pentaethyleneglycol monododecylether (C12E5), decane, water. The dependence of the critical shear rate, at which the transition from the isotropic state to the anisotropic takes place, on membrane volume fraction was studied in temperature ramp experiments at different constant shear rates and in isothermal shear ramp experiments. These results are compared with relaxation experiments from the shear aligned state back to the isotropic. For all these experiments power law exponents in the membrane volume fraction between 1.6 and 2.8 were found, which are rather low compared to values of current theories. The values found for the inverse critical shear rate and the decay times from the relaxation experiments differ by four orders of magnitude. 相似文献
53.
The sorption of Pu(VI) onto TiO(2) was studied as a function of pH (2-10) and Pu concentration (10(-8)-10(-4) M) under an N(2) atmosphere, in 0.016 and 0.1 M NaClO(4). A batch-wise method was used, in which pH was measured in separate experimental containers after removal of a sample to determine the amount of Pu that had been sorbed. As Pu is radioactive, it was used as a tracer and measured by liquid scintillation counting. No ionic strength dependence was discerned, which was taken as an indication of inner sphere complex formation. In the interval of pH 2-7 the system could be described by the formation of two positively charged surface complexes using a 1-pK Stern model. Sorption of the plutonyl ion (PuO(2)(2+)) and the first hydrolysis species (PuO(2)(OH)(+)) was estimated using FITEQL to logK(1)=6.9 and logK(2)=1.4, respectively. 相似文献
54.
[formula: see text] Temporary tethering using aluminum or zinc in Diels-Alder reactions made possible the use of otherwise "noncompatible" combinations of dienes and dienophiles, resulting in the one-step formation of substituted cyclohexene 1,2-bis-methanols. Excellent regioselectivity and also significant stereoselectivity were obtained. 相似文献
55.
Kwok WK Olsson RJ Karapetrov G Paulius LM Moulton WG Hofman DJ Crabtree GW 《Physical review letters》2000,84(16):3706-3709
The critical points in untwinned YBa(2)Cu(3)O(7-delta) crystals with dilute columnar defects are investigated. We find a convergence of a first order vortex melting line with an irreversibility line associated with the onset of the Bose glass critical regime at the lower critical point. In addition, we find that columnar defects raise the upper critical point, implying that vortex line meandering is a basic feature controlling its position. 相似文献
56.
van Otterlo A Scalettar RT Zimanyi GT Olsson R Petrean A Kwok W Vinokur V 《Physical review letters》2000,84(11):2493-2496
We study numerically and experimentally the dynamics of driven vortex matter. Our London-Langevin simulations find that the critical current exhibits a peak both across the Bragg glass to vortex glass transition and across the melting line. The peak is accompanied by a clear crossing of the I-V curves. We report transport measurements on untwinned YBCO crystals, in complete accordance with these findings. At higher drives disorder is averaged to reduced values, and in three dimensions the vortices reorder into a "moving solid." The effect of the disorder can be well represented with a "shaking temperature" which is inversely proportional to the velocity. 相似文献
57.
Annica Tevell Åberg Charlotte Olsson Ulf Bondesson Mikael Hedeland 《Journal of mass spectrometry : JMS》2009,44(7):1026-1037
This paper describes a study where the metabolism of the non‐steroidal anti‐inflammatory drug meloxicam was investigated in six horses and in the filamentous fungus Cunninghamella elegans. The metabolites identified were compared between the species, and then the fungus was used to produce larger amounts of the metabolites for future use as reference material. C. elegans proved to be a good model of phase I meloxicam metabolism in horses since all four metabolites found were the same in both species. Apart from the two main metabolites, 5′‐hydroxymethylmeloxicam and 5′‐carboxymeloxicam, a second isomer of hydroxymeloxicam and dihydroxylated meloxicam were detected for the first time in horse urine and the microbial incubations. Phase II metabolites were not discovered in the C. elegans samples but hydroxymeloxicam glucuronide was detected intact in horse urine for the first time in this study. Urine from six horses was further analyzed in a semi‐quantitative sense and 5′‐hydroxymethylmeloxicam gave peaks with much higher intensity compared to the parent drug and the other metabolites, and was detected for at least 14 days after the last given dose in some of the horses. From the results presented in this article, we suggest that analytical methods developed for the detection of meloxicam in horse urine after prohibited use should focus on the 5′‐hydroxymethyl metabolite and that C. elegans can be used to produce large amounts of this metabolite for potential future use as a reference compound. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
58.
R. Gran Olsson 《Archive of Applied Mechanics (Ingenieur Archiv)》1941,12(2):123-132
Zusammenfassung Die Grundgleichung vonK. Federhofer für die Ausbiegung einer nur am Au\enrand gedrückten Kreisringplatte bei kräftefreiem Innenrand wird darauf hin untersucht, für welche Exponentenn des Plattenprofilsh=c r
n
eine Integration mit Hilfe der Whittakerschen Funktion möglich ist. Au\er den durch Zylinderfunktionen bereits behandelten Fällenn=0 undn=(5–)/6, ergibt sich je eine Schar von hyperbolischen und parabolischen Profilen, wobei der Exponentn von der Querdehnungszahl des Plattenwerkstoffs abhängt. Es werden die Lösungen der Federhoferschen Grundgleichung mit Hilfe der Whittakerschen Funktion explizit hingeschrieben, und in den Fällenn=0 undn=(5–)/6 die Zurückführung auf Zylinderfunktionen gezeigt. Die Knickbedingungen für die drei möglichen Auflagerungen bei querkraftfreiem Innenrand werden aufgestellt. Die numerische Auswertung soll später mitgeteilt werden. 相似文献
59.
A.L. Vasiliev E.A. Stepantsov Z.G. Ivanov E. Olsson K. Verbist G. Van Tendeloo 《Interface Science》1997,5(4):223-230
The structure of the artificial grain boundaries in Al2O3 bicrystals withY3Al5O12 and Y-stabilizedZrO2 (Y-ZrO2) intermediate layers was studiedwith high resolution electron microscopy, electron diffraction and energydispersive X-ray analysis. TheY3Al5O12 intermediate layer wasfound to be polycrystalline with three different orientation relationshipsbetween the 2O3 and theY3Al5O12. The structure of theY3Al5O12/2O3 interfaces is described.Also2O3 bicrystals with an Y-ZrO2/2O3/Y-ZrO2/2O3/Y-ZrO2intermediate layer, prepared at two different temperatures, werestudied.Recry stallization of the intermediate layers occurred during thesolid phase intergrowth of the 2O3 bicrystalsparts and only an Y-ZrO2 layer was found as intermediatelayer. The misorientation between the consecutive Y-ZrO2grains was less than 1.5°. Misfit dislocations and atomic height stepsdecorate the Y-ZrO2/2O3interface. 相似文献
60.
Per Martin Björemark Dr. Susanne Olsson Dr. Theonitsa Kokoli Prof. Mikael Håkansson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(24):8750-8753
Even though the isolation of tetrahedral stereoisomers usually presents a synthetic challenge, a highly enantioenriched tetrahedral silver complex could be easily accessed by either crystallization or Viedma ripening. The overall preparation may be regarded as an example of absolute asymmetric synthesis. Experimental results indicate that both crystallization and Viedma ripening follow a similar cluster‐controlled mechanism. 相似文献