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801.
In this paper we describe a method for separating a combination of a chaotic time series and a discrete-valued signal. The method uses a feedback technique stabilised using knowledge of the chaotic system and the discrete nature of the signal. It is not based on a linearization of the dynamics, and therefore, unlike previously proposed separation methods, does not require that the signal be small. Nor does it make any assumptions about the relative timescales of the signal and the chaotic time series. 相似文献
802.
803.
S. A. Plaksa 《Ukrainian Mathematical Journal》1993,45(8):1316-1320
Under the minimal assumptions imposed on given spaces, the sufficient conditions are established, under which the compositionBA of operatorsA andB has the Noether property and is normally solvable. Similar conditions, guaranteeing that the operatorA is normally solvable or possesses the Noether property, are obtained for the operatorsB andBA.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 45, No. 8, pp. 1177–1180, August, 1993. 相似文献
804.
An iterative method from the class of completely implicit methods (CIM) is proposed for solving the equation of the velocity
potential of elliptical-hyperbolic type. The advantage of the proposed method compared to other CIM schemes is demonstrated
in application to mixed perfect gas flows in a nozzle of a given shape. Accuracy issues, rate of convergence, and various
techniques of ensuring stability in the hyperbolic region are discussed.
Translated from Chislennye Metody v Matematicheskoi Fizike, Published by Moscow University, Moscow, 1996, pp. 39–51. 相似文献
805.
Convective heat transfer from an array of small, cylindrical bodies of arbitrary shape in an unbounded, two-dimensional domain is a singular perturbation problem involving an infinite logarithmic expansion in the small parameter ε, representing the order of magnitude of the size of the bodies. Using the method of matched asymptotic expansions, we formulate a hybrid asymptotic-numerical method to solve for the dimensionless, steady-state temperature. We assume that the velocity field of the fluid surrounding the bodies is arbitrary but known. From our asymptotic solution for an arbitrary velocity field, we present the results for two special cases: a uniform flow field and a simple shear flow field. We demonstrate the asymptotic results of the hybrid method through a number of examples and, in a particular case, we compare these results to an exact analytical solution. 相似文献
806.
807.
This research extends previous work with dynamic models to manage groundwater quality by using the consumptive nitrate use rate instead of the nitrate application rate. The analysis indicates that misspecification results in overestimation of economic benefits, and supra-optimum nitrogen fertilizer application rates and groundwater nitrate stocks at a steady state. 相似文献
808.
809.
Fe(II)--Fe(III) hydroxy-chloride, -sulphate and -carbonate were prepared by oxidation of a ferrous hydroxide precipitate in anion-containing aqueous solutions. The compounds are characterized by monitoring the redox potential Eh and the pH of stochiometric suspension vs time with the appropriate concentration ratios. X-ray diffraction allows us to characterize the crystal structure by distinguishing “green rust one” (GR1) from “green rust two” (GR2). Since green rusts (GRs) are of a pyroaurite-sjögrenite-like structure, i.e., consisting of intercalated foreign anions and water molecules in the interlayers between the brucite-like layers of Fe(OH)2, their chemical formulae can be determined from the Mössbauer spectra. Three quadrupole doublets are observed: D1 and D2 correspond to a ferrous state with isomershift IS of about 1.27 mm s-1 and quadrupole splittings QS of about 2.85 and 2.60 mm s-1, respectively, whereas D3 corresponds to a ferric state with IS and QS of about 0.4 mm s-1. The hyperfine parameters of these doublets are similar from one green rust to another but their intensity ratios vary considerably. Finally, Eh and pH equilibrium diagrams of the Fe species in the presence of chloride, sulphate and carbonate anions contained within the water solution are drawn and the thermodynamic conditions of existence and degrees of oxidation of green rusts are discussed. 相似文献
810.
V. A. Zubkov S. N. Kovalenko V. P. Chernykh S. M. Ivkov 《Chemistry of Heterocyclic Compounds》1994,30(6):665-670
Methods of synthesizing previously unknown derivatives of coumarin — 2-(N-R-imino)-2H-1-benzopyrans, where R = Alk, Ar — are proposed. Possibilities of alternative synthetic schemes are discussed, and hypotheses concerning probable mechanisms of the reactions are formulated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 760–766, June, 1994. Original article submitted May 23, 1994. 相似文献