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581.
582.
The structures of compounds M
2
I
MII(SEO4)2 (MI=K, Tl; MII=Cu and Ni), were studied using IR, electronic and EPR spectra. The results indicate a hexacoordination of both central atoms, and a bridging function of selenato groups, the mode of their coordination varies with MI and MII. The compound Tl2Cu(SeO4)2 was prepared also in the amorphous glassy form, although with partial decomposition. It is presumed that in the homogeneous smaragd-green material -Cu-O-Cu-, -Cu-OSeO2-Cu- and -Cu-OSeO3-Cu- bridges are present simultaneously. The course of the thermal decomposition of the studied compounds depends on the nature of the MI and MII cations. According to powder X-ray patterns, the decomposition products do not contain individual oxides. Nearly complete removal of selenium was observed in the decomposition of hydrated ammonium double selenates of Ni(II) and Cu(II).
Zusammenfassung Mittels IR-, Elektronen- und EPR-Spektren wurden die Strukturen der Verbindungen M 2 I MII (SeO4)2 mit MI=K und Tl sowie MII=Cu and Ni bestimmt. Die Ergebnisse zeigen eine Hexakoordination beider Zentralatome und eine Brückenfunktion der Selenatgruppen, deren Koordination sich mit MI und MII ändert. Die Verbindung Tl2Cu(SeO4)2 wurde, wenn auch unter geringen Zerfalles, auch in einer amorphen Glasform hergestellt. Es wird angenommen, daß in den Smaragdgrün-Stoffen gleichzeitig-Cu-O-Cu-, -Cu-OSeO2-Cu- und -Cu-OSeO3-Cu- Brücken vorkommen. Der Verlauf der thermischen Zersetzung der untersuchten Verbindungen hängt von der Art der MI und MII-Kationen ab. In Bezugnahme auf Röntgenpulverdiffraktionsaufnahmen enthalten die Zersetzungsprodukte keine getrennten Oxide. Beim Zerfall von hydratierten Ammoniumdoppelselenaten von Ni(II) und Cu(II) wurde eine fast vollständige Abgabe von Selen beobachtet.
M 2 I Mii(SeO4)2, i — , , ii , - , . , - i ii. Tl2Cu(SeO4)2 , . , ----, --OSeO2- -Cu-OSeO3-u-. i ii. , . .相似文献
583.
Zsolt Tuza 《组合设计杂志》1995,3(2):89-99
Proving a conjecture of Aigner and Triesch, we show that every graph G = (V,E) without isolated vertices and isolated edges admits an edge labeling ξ: E → {0,1}m with binary vectors of length m = [log2 n] + 1 such that the sums. CALLING STATEMENT : (taken modulo 2 componentwise) are mutually distinct, provided that n is sufficiently large. The proof combines probabilistic arguments with explicitly constructed Steiner systems. © 1995 John Wiley & Sons, Inc. 相似文献
584.
Gyula Pap 《Journal of Theoretical Probability》1990,3(4):563-577
If
a,T
is a Gaussian measure on a Hilbert space with meana and covariance operatorT, andr is a fixed positive number, then the functiong(a,T)=
a,T
{xr} satisfies the equation
相似文献
585.
Zsolt Tuza 《Graphs and Combinatorics》1991,7(1):89-93
Upper and lower bounds are given for the minimum number of perfect (induced or partial) subgraphs covering or partitioning the vertex set or the edge set of a graph ofn vertices. Also, weighted versions of the problems are investigated.Research supported in part by the OTKA Research Fund of the Hungarian Academy of Sciences, Grant No. 1812. 相似文献
586.
Karoly Bezdek Zsolt Langi Marton Naszodi Peter Papez 《Discrete and Computational Geometry》2007,38(2):201-230
We study two notions. One is that of spindle convexity. A set of circumradius not greater than one is spindle convex if, for
any pair of its points, it contains every short circular arc of radius at least one, connecting them. The other objects of
study are bodies obtained as intersections of finitely many balls of the same radius, called ball-polyhedra. We find analogues
of several results on convex polyhedral sets for ball-polyhedra. 相似文献
587.
In this paper we consider discrete time forward interest rate models. In our approach, unlike in the classical Heath–Jarrow–Morton
framework, the forward rate curves are driven by a random field. Hence we get a general interest rate structure. Our aim is
to give an overview of our results in such a model on the following questions: no-arbitrage conditions, maximum likelihood
estimation of the volatility, as well as the joint estimation of the parameters and the asymptotic behaviour of the estimators,
relationship with continuous models. Finally we give discussion on the practical problems of the estimation and we show several
numerical results on the statistics of such models.
This research has been supported by the Hungarian Scientific Research Fund under Grants No. OTKA–F046061/2004 and OTKA–T048544/2005. 相似文献
588.
A spatial autoregressive process with two parameters is investigated both in the stable and in the unstable case. It is shown
that the limiting distribution of the least squares estimator of these parameters is normal and the rate of convergence is
n
3/2 if one of the key parameters equals zero and n otherwise. 相似文献
589.
590.
Zsolt Patakfalvi 《Discrete Mathematics》2008,308(12):2351-2365
A graph is called normal if its vertex set can be covered by cliques Q1,Q2,…,Qk and also by stable sets S1,S2,…,Sl, such that Si∩Qj≠∅ for every i,j. This notion is due to Körner, who introduced the class of normal graphs as an extension of the class of perfect graphs. Normality has also relevance in information theory. Here we prove, that the line graphs of cubic graphs are normal. 相似文献
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