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31.
Lubomír Kubáček 《Mathematica Slovaca》2007,57(6):571-588
The multivariate model, where not only parameters of the mean value of the observation matrix, but also some other parameters
occur in constraints, is considered in the paper. Some basic inference is presented under the condition that the covariance
matrix is either unknown, or partially unknown, or known.
Supported by the grant of the Council of Czech Republic MSM 6 198 959 214. 相似文献
32.
Hydrogels of N‐vinylimidazole (VI) and sodium styrenesulfonate (SSS) were synthesized in aqueous solution by radical crosslinking copolymerization with N,N′‐methylene‐bis(acrylamide) as crosslinker. Swelling in several saline solutions was measured for hydrogel samples synthesized with different comonomer concentrations (CT = 10, 25, or 40%) and with SSS mole fractions covering a broad range (fSSS = 0–0.7), while the crosslinker ratio was 2 wt % in all cases. The degree of swelling in aqueous solution with a specific ionic strength (μ), plotted versus the SSS composition of the feed, shows a minimum for any set of samples synthesized with a fixed CT. The dependence of swelling on μ shows both polyelectrolyte (fSSS beyond the minimum) and antipolyelectrolyte behaviors (in the low fSSS limit). It was found that the nonGaussian factor of the crosslinking density and the polymer‐solvent interaction parameter increase with fSSS for any CT. Moreover, in the low fSSS limit, the osmotic swelling pressure is governed not only by the ionic contribution, but also by the polymer‐solvent mixing and, the concentration of mobile counterions inside the gel is not proportional to the net fixed charge but to the addition of cationic and anionic side groups, what discards the formation of ionic pairs. The antipolyelectrolyte effect is interpreted as due to the increasing protonation of VI as μ goes up. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1683–1693, 2007 相似文献
33.
The presented one-capacitor pinch driver, designed as a compact coaxial structure (including spark-gap and discharge section) consistent with the capacitor output, generates a current of 200 kA with 700 ns quarter-period, suitable for studying the optimization of Z-pinch radiative characteristics. The driver is described, measurements of its parameters summarized, and relations to our previous and future activities briefly reviewed.This work was supported in part by the Grant Agency of the Czech Republic under contract No. 202/93/1023. 相似文献
34.
The sulphur K-edge x-ray absorption spectra of SO2 multilayer and of SO2 submonolayer adsorbed on Cu(100) are analysed. It is found that the dominant spectral features are of a molecular origin. The results support earlier findings that the SO2 molecule stands perpendicular to the surface. Use of non-selfconsistent potentials does not lead to a good quantitative agreement between theory and experiment. 相似文献
35.
E. Hernández L. Rodríguez-Marín 《Journal of Optimization Theory and Applications》2007,134(1):119-134
In this paper, we study optimization problems where the objective function and the binding constraints are set-valued maps
and the solutions are defined by means of set-relations among all the images sets (Kuroiwa, D. in Takahashi, W., Tanaka, T.
(eds.) Nonlinear analysis and convex analysis, pp. 221–228, 1999). We introduce a new dual problem, establish some duality theorems and obtain a Lagrangian multiplier rule of nonlinear type
under convexity assumptions. A necessary condition and a sufficient condition for the existence of saddle points are given.
The authors thank the two referees for valuable comments and suggestions on early versions of the paper. The research of the
first author was partially supported by Ministerio de Educación y Ciencia (Spain) Project MTM2006-02629 and by Junta de Castilla
y León (Spain) Project VA027B06. 相似文献
36.
It is shown that the presence of mixed-culture growth in batch fermentation processes can be very accurately inferred from total biomass data by means of the wavelet analysis for singularity detection. This is accomplished by considering simple phenomenological models for the mixed growth and the more complicated case of mixed growth on a mixture of substrates. The main quantity provided by the wavelet analysis is the Hölder exponent of the singularity that we determine for our illustrative examples. The numerical results point to the possibility that Hölder exponents can be used to characterize the nature of the mixed-culture growth in batch fermentation processes with potential industrial applications. Moreover, the analysis of the same data affected by the common additive Gaussian noise still lead to the wavelet detection of the singularities although the Hölder exponent is no longer a useful parameter. 相似文献
37.
We continue the studies on the so–called genuine Bernstein–Durrmeyer operators U
n
by establishing a recurrence formula for the moments and by investigating the semigroup T(t) approximated by U
n
. Moreover, for sufficiently smooth functions the degree of this convergence is estimated. We also determine the eigenstructure
of U
n
, compute the moments of T(t) and establish asymptotic formulas.
Received: January 26, 2007. 相似文献
38.
Fe–Al alloys around the concentration of 30 at. % Al present re-entrant spin-glass behaviour at low temperatures. This behaviour is not completely understood and Mössbauer spectroscopy, combined with other experimental techniques, is useful to describe and explain this behaviour. Results show that the Mössbauer spectra coincide with the magnetic behaviour showed in literature and they can be explained as a magnetic cluster system whose magnetic clusters are getting smaller when the temperature is decreasing. When the temperature is reaching to the spin-glass transition at 92 K the spins in the paramagnetic matrix are moving slower and below this transition the spins are completely frozen. 相似文献
39.
G.M. Bilmes D.J.O. Orzi O.E. Martínez A. Lencina 《Applied physics. B, Lasers and optics》2006,82(4):643-648
The measurement of surface cleanliness is a significant problem in many industrial and technological processes. Existing methods are based on laboratory procedures, that are not performed in real time, can not be automated, and usually are restricted to a small portion of the sample. In this study we describe a new method for real time measurement of the amount of surface dirt or contamination deposited on a surface. It relies on the ablation of the surface dirt film by means of a short laser pulse, and the subsequent measurement of the emitted sound. The intensity of the sound is proportional to the amount of surface dirt and provides a direct measurement of the cleanliness of the surface. We also developed a reference sample for calibration, based on a uniform distribution of dots printed on white paper. The density and the dot size can be easily modified providing a homogeneous, uniform and reproducible standard for the measurement. Based on this method, we designed, developed and patented the first industrial instrument for on-line determination of the degree of cleanliness of manufactured cold rolled steel plate bobbins. PACS 79.20.D; 81.70.C; 42.62. 相似文献
40.
A. Veiga N. Martínez P. Mendoza Zélis G. A. Pasquevich F. H. Sánchez 《Hyperfine Interactions》2006,167(1-3):905-909
A prototype of a programmable constant-velocity scaler is presented. This instrument allows the acquisition of partial Mössbauer spectra in selected energy regions using standard drivers and transducers. It can be fully operated by a remote application, thus data acquisition can be automated. The instrument consists of a programmable counter and a constant-velocity reference. The reference waveform generator is amplitude modulated with 13-bit resolution, and is programmable in a wide range of frequencies and waveforms in order to optimize the performance of the transducer. The counter is compatible with most standard SCA, and is configured as a rate-meter that provides counts per selectable time slice at the programmed velocity. As a demonstration of the instrument applications, a partial Mössbauer spectrum of a natural iron foil was taken. Only positive energies were studied in 512 channels, accumulating 20 s per channel. A line width of 0.20 mm/s was achieved, performing with an efficiency of 80%. 相似文献