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181.
Danuta Potoczna-Petru Leszek K?piński Ludwina Krajczyk 《Reaction Kinetics and Catalysis Letters》2009,97(2):321-327
The interaction of 1 and 4 nm thick Co films with SiO2 support in vacuum at high temperature has been investigated by TEM, SAED and HRTEM methods. It was found that annealing in
vacuum at 800 °C caused the transformation of the smallest Co particles into Co2Si silicide. 相似文献
182.
Leszek Dziczkowski 《PAMM》2008,8(1):10205-10206
The proposed definition of the penetration depth of eddy currents, more convenient for tests with defectometers, is based on the model: measuring coil placed above non–magnetic conductive foil. The designated penetration depth is equivalent to the penetration depth of a measuring device and is subject of practical observations. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
183.
The Mortar Element Method with Locally Nonconforming Elements 总被引:5,自引:0,他引:5
Leszek Marcinkowski 《BIT Numerical Mathematics》1999,39(4):716-739
We consider a discretization of linear elliptic boundary value problems in 2-D by the new version of the mortar finite element method which uses locally nonconforming Crouzeix-Raviart elements. We show that if a solution of the original differential problem belongs to the space H
2(), then an error is of the same order as in the standard nonconforming finite element method. We also propose an additive Schwarz method of solving the discrete problem and show that its rate of convergence is almost optimal. 相似文献
184.
Michal Falkowski Amanda Leda Tomasz Rebis Jaroslaw Piskorz Lukasz Popenda Mina Hassani Dariusz T. Mlynarczyk Michal P. Marszall Grzegorz Milczarek 《Molecules (Basel, Switzerland)》2022,27(14)
A sulfanyl porphyrazine derivative with peripheral phthalimide moieties was metallated with cobalt(II) and iron(II) metal ions. The purity of the macrocycles was confirmed by HPLC, and subsequently, compounds were characterized using various analytical methods (ES-TOF, MALDI-TOF, UV–VIS, and NMR spectroscopy). To obtain hybrid electroactive electrode materials, novel porphyrazines were combined with multiwalled carbon nanotubes. The electrocatalytic effect derived from cobalt(II) and iron(II) cations was evaluated. As a result, a significant decrease in the overpotential was observed compared with that obtained with bare glassy carbon (GC) or glassy carbon electrode/carbon nanotubes (GC/MWCNTs), which allowed for sensitive determination of hydrogen peroxide in neutral conditions (pH 7.4). The prepared sensor enables a linear response to H2O2 concentrations of 1–90 µM. A low detection limit of 0.18 μM and a high sensitivity of 640 μA mM−1 cm−2 were obtained. These results indicate that the obtained sensors could potentially be applied in biomedical and environmental fields. 相似文献
185.
Ab initio calculations have been carried out for ammonia dimers with 4-31G and 6-31G* basis sets. The results are corrected for basis-set superposition error. For the ammonia dimer, the stability of the linear form is comparable to that of the cyclic form. The localized orbitals for both dimers are discussed. 相似文献
186.
Leszek Malkinski Nicholas Cramer Andrew Hutchison Robert Camley Zbigniew Celinski Danuta Skrzypek Ron B. Goldfarb 《Journal of magnetism and magnetic materials》2002,240(1-3):261-263
A new type of ferromagnet/antiferromagnet structure (Fe/KCoF3) was deposited by molecular beam epitaxy. Unidirectional and uniaxial anisotropies of 5.1 and 3.4 kA/m were measured at 23 K using ferromagnetic resonance. Magnetization measurements at 5 K showed a hysteresis loop shift of 6 kA/m due to exchange bias. Significant enhancement of four-fold anisotropy was found at low temperatures in the samples with polycrystalline KCoF3 structure. 相似文献
187.
Leszek S. Zaremba 《Mathematical and Computer Modelling》1991,15(12):81-89
We study here a rather general class of nonlinear control systems with uncertain dynamics involving perturbating variables, without assuming any statistical information on them. Contrary to majority of publications on uncertain control problems, we study here the value function and seek for optimal (-optimal) control policies. Our four theorems, covering all possible situations that may happen in the context of relationships between the influence of the control parameters on the system versus the perturbating parameters, give both upper and lower bounds for the value function in terms of solutions of simplified unperturbed control problems. They also provide constructive procedures for finding strategies that, under additional assumptions, appear to be -optimal control policies in the class of so-called step guided strategies introduced by us in a very recent paper. 相似文献
188.
Leszek Klukowski 《Annals of Operations Research》1994,51(5):241-261
In this paper, some probabilistic properties of the nearest adjoining order (NAO) method are presented. They have been obtained under weaker assumptions than those commonly used, i.e. it is not assumed that comparisons are not independent and that probability of comparison errors are known. The results presented comprise the evaluation of the probability of obtaining an errorless solution with the use of the NAO method; asymptotic properties of this solution derived under the assumption that comparisons of different pairs (i.e. pairsx
i
,x
j
andx
r
,x
r
fori r,s andj r,s) are not correlated — for the case of one expert. An extension of results for the case ofN > 1 independent experts is also presented. This extension is accomplished by including an additional step — the aggregation of comparisons made by all experts for each pair of objects. Two ways of such an aggregation are analyzed: the averaging of experts' opinions and the majority principle. In the latter case, the result of the comparison is the same as the opinion of the majority of experts. The results obtained indicate an exponential convergence of the probability of the NAO solution to an errorless one in both cases. However, an application of the majority principle leads to a minimization problem, which is the same as in the case ofN = 1 and is much simpler than that corresponding to averaging of comparisons. 相似文献
189.
Peter Nyikos Leszek Piatkiewicz 《Proceedings of the American Mathematical Society》1996,124(1):303-314
In 1975 E. K. van Douwen showed that if is a family of Hausdorff spaces such that all finite subproducts are paracompact, then for each element of the box product the -product is paracompact. He asked whether this result remains true if one considers uncountable families of spaces. In this paper we prove in particular the following result: Let be an infinite cardinal number, and let be a family of compact Hausdorff spaces. Let be a fixed point. Given a family of open subsets of which covers , there exists an open locally finite in refinement of which covers . We also prove a slightly weaker version of this theorem for Hausdorff spaces with ``all finite subproducts are paracompact" property. As a corollary we get an affirmative answer to van Douwen's question.
190.
Hubertus Nickel Leszek Niewolak Joanna Zurek Willem J. Quadakkers 《Mikrochimica acta》2004,148(3-4):241-249
The development of modern power generation systems with higher thermal efficiency requires the use of constructional materials of higher strength and improved resistance to the aggressive service atmospheres. In this paper the following examples are discussed:1) The oxidation behaviour of 9% (w/w) Cr steels in simulated combustion gases: the effects of O2 and H2O content on the oxidation behaviour of 9% (w/w) Cr steels in the temperature range of 600–800°C showed that in dry oxygen a protective scale was formed with an oxidation rate controlled by diffusion. However, in the presence of water vapour, after an incubation period, the scale became non-protective as a result of a change in the oxidation mechanism.Oxidation experiments on 10% (w/w) Cr steel in simulated steam atmosphere at 650°C have shown that a haematite layer is formed. The investigation suggests that several independent processes, such as oxide dissociation and solid state diffusion of iron cations in the scale, significantly contribute to the overall oxide growth process.2) The development of light-weight intermetallics based on TiAl-basis: TiAl-based intermetallics are promising materials for future turbine components because of their combination of high temperature strength and low density. These alloys, however, exhibits poor oxidation resistance at temperatures above 700°C. The experimental results showed that the oxidation behaviour of TiAl-based intermetallics can be significantly improved by minor additions of 1–2 at-% silver. 相似文献