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101.
Evgueni I. Gordienko J. Adolfo Minjárez-Sosa 《Mathematical Methods of Operations Research》1998,48(1):37-55
The paper deals with a class of discrete-time Markov control processes with Borel state and action spaces, and possibly unbounded
one-stage costs. The processes are given by recurrent equations x
t
+1=F(x
t
,a
t
,ξ
t
), t=1,2,… with i.i.d. ℜ
k
– valued random vectors ξ
t
whose density ρ is unknown. Assuming observability of ξ
t
, and taking advantage of the procedure of statistical estimation of ρ used in a previous work by authors, we construct an
average cost optimal adaptive policy.
Received March/Revised version October 1997 相似文献
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103.
Evgueni Vassiliev 《Mathematical Logic Quarterly》2010,56(1):35-41
We continue the study of the connection between the “geometric” properties of SU ‐rank 1 structures and the properties of “generic” pairs of such structures, started in [8]. In particular, we show that the SU‐rank of the (complete) theory of generic pairs of models of an SU ‐rank 1 theory T can only take values 1 (if and only if T is trivial), 2 (if and only if T is linear) or ω, generalizing the corresponding results for a strongly minimal T in [3]. We also use pairs to derive the implication from pseudolinearity to linearity for ω ‐categorical SU ‐rank 1 structures, established in [7], from the conjecture that an ω ‐categorical supersimple theory has finite SU ‐rank, and find a condition on generic pairs, equivalent to pseudolinearity in the general case (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
104.
Christophe Hecquet Franck Delmotte Marie-Fran?oise Ravet-Krill Sébastien de Rossi Arnaud Jérome Fran?oise Bridou Fran?oise Varnière Evgueni Meltchakov Frédéric Auchère Angelo Giglia Nicola Mahne Stefano Nanaronne 《Applied Physics A: Materials Science & Processing》2009,95(2):401-408
In this paper, we present a study on two-channel multilayer mirrors which can operate at two wavelengths in Extreme Ultraviolet
(EUV) spectral range. We propose a new method to design two-channel EUV multilayer mirrors with enhanced spectral selectivity.
The mirror structure is a stack of two periodic multilayers separated by a buffer layer. We have defined the main parameters
which allow adjustment of the distance between different order Bragg’s peak and of wavelength positions of reflectivity minima.
Two mirrors have been designed and deposited for solar EUV telescope applications by using this method. The first mirror reflects
Fe IX–X line (17.1 nm) and Fe XVI (33.5 nm) lines with attenuation of the He II line (30.4 nm). The second mirror reflects
Fe IX–X and He II lines with attenuation of Fe XV (28.4 nm) and Fe XVI lines. Measurements with synchrotron radiation source
confirm that, in both cases, for these mirrors, we are able to adjust reflectivity maxima (Bragg peak position) and minima.
Such multilayers offer new possibilities for compact design of multi-wavelength EUV telescopes and/or for high spectral selectivity. 相似文献
105.
Anastasia Virnovskaia Jasmina Hafizovic Evgueni Kleimenov Michael Hävecker Axel Knop-Gericke Unni Olsbye 《Surface science》2007,601(1):30-43
Calcined hydrotalcite with or without added metal (Mg(Al)O, Pt/Mg(Al)O and Pt,Sn/Mg(Al)O) have been investigated with in situ X-ray photoelectron spectroscopy (XPS) during ethane dehydrogenation experiments. The temperature in the analysis chamber was 450 °C and the gas pressure was in the range 0.3-1 mbar. Depth profiling of calcined hydrotalcite and platinum catalysts under reaction, oxidation and in hydrogen-water mixture was performed by varying the photon energy, covering an analysis depth of 10-21 Å. It was observed that the Mg/Al ratio in the Mg(Al)O crystallites does not vary significantly in the analysis depth range studied. This result indicates that Mg and Al are homogeneously distributed in the Mg(Al)O crystallites. Catalytic tests have shown that the initial activity of a Pt,Sn/Mg(Al)O catalyst increases during an activation period consisting of several cycles of reduction-dehydrogenation-oxidation. The Sn/Mg ratio in a Pt,Sn/Mg(Al)O catalyst was followed during several such cycles, and was found to increase during the activation period, probably due to a process where tin spreads over the carrier material and covers an increasing fraction of the Mg(Al)O surface. The results further indicate that spreading of tin occurs under reduction conditions.A PtSn2 alloy was studied separately. The surface of the alloy was enriched in Sn during reduction and reaction conditions at 450 °C. Binding energies were determined and indicated that Sn on the particle surface is predominantly in an oxidised state under reaction conditions, while Pt and a fraction of Sn is present as a reduced Pt-Sn alloy. 相似文献
106.
Evgueni Kassianov Thomas Ackerman 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,91(2):211-226
Both individual and combined effects of the horizontal and vertical variability of cumulus clouds on solar radiative transfer are investigated using a two-dimensional (x- and z-directions) cloud radar dataset. This high-resolution dataset of typical fair-weather marine cumulus is derived from ground-based cloud radar observations. The domain-averaged (along x-direction) radiative properties are computed by a Monte Carlo method. It is shown that (i) different cloud-scale resolutions can be used for accurate calculations of the mean absorption, upward and downward fluxes; (ii) the resolution effects can depend strongly on the solar zenith angle; and (iii) a few cloud statistics can be successfully applied for calculating the averaged radiative properties. 相似文献
107.
An inner function which is not weak outerUne fonction intérieure qui n'est pas faiblement extérieure
Evgueni Doubtsov 《Comptes Rendus Mathematique》2002,334(11):957-960
We construct a nonvanishing inner function I in the unit ball such that the subspace IHp(B) is not weakly dense in the Hardy space Hp(B), with 0<p<1. To cite this article: E. Doubtsov, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 957–960. 相似文献
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109.
110.
Evgueni Gorobets 《Tetrahedron letters》2004,45(18):3597-3601
A series of optically pure 3,3′-bis(RO)-MeO-BIPHEP derivatives are prepared and used in palladium catalyzed asymmetric transformations. The phosphine oxide of (±)-5 is prepared in four steps from p-methoxyphenol and resolved using the novel resolving reagent chloro(l-menthoxy)dimethylsilane. Subsequent conversions provide catalysts 8 and 9. Ligands 6, 7 and 10 are prepared in six steps from p-methoxyphenol and the phosphine oxides of 6 and 7, and 10 are resolved using di-p-toluoyl- and dibenzoyl-l-tartaric acid, respectively. (R)-3,3′-Bispivalate 8 is superior to the other catalysts in asymmetric Heck reaction with 2,3-dihydrofuran while (R)-(+)-bis(tolyloxy) 10 and (+)-(R)-sugar derivative 9 are better in the Pd-catalyzed polyene cyclization; however, the absolute sense of chirality in the product from the polyene cyclization was reversed to that obtained when (R)-(+)-BINAP and (R)-(+)-MeO-BIPHEP were used. 相似文献