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31.
32.
A geometric approach to asymptotic expansions for large-deviation probabilities, developed for the Gaussian law by Breitung and Richter [J. Multivariate Anal.,58, 1–20 (1996)], will be extended in the present paper to the class of spherical measures by utilizing their common geometric properties. This approach consists of rewriting the probabilities under consideration as large parameter values of the Laplace transform of a suitably defined function, expanding this function in a power series, and then applying Watson’s lemma. A geometric representation of the Laplace transform allows one to combine the global and local properties of both the underlying measure and the large-deviation domain. A special new type of difficulty is to be dealt with because the so-called dominating points of the large-deviation domain degenerate asymptotically. As is shown in Richter and Schumacher (in print), the typical statistical applications of large-deviation theory lead to such situations. In the present paper, consideration is restricted to a certain two-dimensional domain of large-deviations having asymptotically degenerating dominating points. The key assumption is a parametrized expansion for the inverse $\bar g^{ - 1} $ of the negative logarithm of the density-generating function of the two-dimensional spherical law under consideration. 相似文献
33.
Recently, differential geometric properties of embedded projective varieties have gained increasing interest. In this note, we consider plane algebraic curves equipped with the Fubini--Study metric from2 () and give an estimate for the diameter in terms of the degree, initiated in a paper by F. A. Bogomolov. 相似文献
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35.
Experimental data are presented for the angular dependence of the relative flux, the mean energy and the speed ratio of deuterium molecules desorbing from a Ni(111) crystal surface at a surface temperature of Ts = 1143 K and at sulphur coverages ranging between 30% and less than 2% of a monolayer.The angular flux distribution is sharply peaked in the forward direction (cosdθwith 3 ? d ? 5) and the mean energy 〈E〉 of the desorbate depends strongly on the desorption angle θ. For normal desorption is about 700 K higher than Ts and for glancing angles (θ = 80°) it decreases to about 400 K below Ts The results obtained on sulphur free and sulphur covered Ni(111) surfaces are compared with our former data on polycrystalline nickel. The main differences in the kinetic features can be ascribed to the surface roughness. Accordingly, the angular distributions of flux, mean energy, and speed ratio, which deviate strongly from the Knudson and Maxwellian law, do not seem to depend considerably on sulphur coverage and surface structure. A qualitative explanation for these deviations is presented using the principle of detailed balancing. 相似文献
36.
D. Schumacher 《Archiv der Mathematik》1969,20(4):356-364
Ohne Zusammenfassung 相似文献
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G. Severin E. Schumacher und F. Umland 《Fresenius' Journal of Analytical Chemistry》1982,311(3):201-204
Zusammenfassung Der Einfluß der Carbidbeschichtung von Graphitrohren auf die Bestimmung von Cd mit der flammenlosen AAS wurde systematisch untersucht. Dazu wurden die Graphitrohröfen mit Zr-, Nb-, Ta-, Mo- und W-Salzlösungen imprägniert, getrocknet und anschließend zur Einleitung der Carbidbildung bei 2600° C geglüht. Es zeigte sich, daß die Oberflächenbehandlung mit Carbidbildnern insgesamt die Lebensdauer des Graphitrohres in Anwesenheit starker Oxidationsmittel erhöht. Außerdem ließen sich höhere Matrix-Zersetzungstemperaturen ohne Cadmium-Verluste erreichen. Die Beschichtung mit Nb-, Ta- und W-Carbid erbrachte auch eine erhöhte Reproduzierbarkeit. Die günstigsten Ergebnisse lieferte die Ta-Beschichtung mit einer Zersetzungstemperatur von 450° C bei Verwendung von N2-Schutzgas, die bei Anwendung starker Oxidationsmittel auf 600° C gesteigert werden konnte. Damit erlaubt die TaBeschichtung die direkte Cd-Bestimmung selbst in Gegenwart geringer organischer Matrixanteile. Gleichzeitig waren Reproduzierbarkeit und Empfindlichkeit gegenüber dem unbeschichteten Rohr deutlich verbessert.
Herrn Prof. Dr. H. Weisz zum 60. Geburtstag gewidmet 相似文献
Determination of cadmium by flameless atomic-absorption spectroscopy
Summary The influence of coating of graphite furnace tubes with carbide forming metals on the determination of Cd by flameless AAS has been investigated systematically. The graphite furnace tubes have been impregnated with Zr, Nb, Ta, Mo or W salt solutions, dried and subsequently annealed up to 2,600° C to initiate carbide formation. It has been found that the surface treatment with carbide forming metals increased the lifetime of the graphite tube in the presence of strongly oxidizing agents. Furthermore, higher decomposition temperatures could be applied without Cd losses and coating with Nb. Ta and W carbide led to higher reproducibility. Best results have been obtained by coating with Ta allowing a decomposition temperature of about 450° C for N2 as inert gas, that could even be enhanced to 600° C by application of strongly oxidizing agents. Thereby Ta coating makes possible direct Cd determination even in the presence of small organic admixtures to the matrix. At the same time reproducibility and sensitivity were improved as against the uncoated tube.
Herrn Prof. Dr. H. Weisz zum 60. Geburtstag gewidmet 相似文献
39.
Doyle AW Fick J Himmelhaus M Eck W Graziani I Prudovsky I Grunze M Maciag T Neivandt DJ 《Langmuir : the ACS journal of surfaces and colloids》2004,20(21):8961-8965
Structural deformations of lipid hybrid bilayer membranes induced by signal peptideless (SPL) proteins have been studied for the first time using the inherently surface specific nonlinear optical technique of sum frequency generation vibrational spectroscopy. Specifically, deformations of 1,2-distearoylphosphatidylglycerol(DSPG) membranes induced by interaction with FGF-1, a SPL protein which is released asa function of cellular stress through a nonclassical pathway, have been investigated. FGF-1 was found to induce lipid alkyl chain deformations in previously highly ordered DSPG membranes at the extremely low concentration of 1 nM at 60 degrees C. The deformation process was shown to exhibit a degree of reversibility upon removal of the protein by rinsing with buffer solution. 相似文献
40.
The widely used relation alpha; = alpha(0)+Deltaalpha for the electric polarizability, where Deltaalpha is proportional to the r.m.s. charge radius of the system, is revisited within a simple model of two spinless particles bound electromagnetically. A complete set of the relativistic corrections to alpha(0) following from the Breit Hamiltonian is obtained. It is shown that these corrections modify the result for alpha; in comparison to that obtained with alpha(0) taken in the nonrelativistic approximation. We propose that the same situation can take place in the more complicated case of hadrons. Special attention is devoted to the correct definition of the center-of-mass coordinates which are found to be very important. 相似文献