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31.
32.
The kinetics of the reaction of manganese(III) with oxalic acid (OA) has been studied in H2SO4 solutions. Under the experimental conditions of 6 × 10–3 <>0 < 0.4=" mol=">–3 and [H2SO4]0 0.2 mol dm–3 the observed pseudo-first order rate constant k
obs follows the expression
相似文献
33.
Precise dipolar coupling constant distribution analysis in proton multiple-quantum NMR of elastomers
Chassé W López Valentín J Genesky GD Cohen C Saalwächter K 《The Journal of chemical physics》2011,134(4):044907
In this work we present an improved approach for the analysis of (1)H double-quantum nuclear magnetic resonance build-up data, mainly for the determination of residual dipolar coupling constants and distributions thereof in polymer gels and elastomers, yielding information on crosslink density and potential spatial inhomogeneities. We introduce a new generic build-up function, for use as component fitting function in linear superpositions, or as kernel function in fast Tikhonov regularization (ftikreg). As opposed to the previously used inverted Gaussian build-up function based on a second-moment approximation, this method yields faithful coupling constant distributions, as limitations on the fitting limit are now lifted. A robust method for the proper estimation of the error parameter used for the regularization is established, and the approach is demonstrated for different inhomogeneous elastomers with coupling constant distributions. 相似文献
34.
35.
Redundant constraints in linear inequality systems can be characterized as those inequalities that can be removed from an
arbitrary linear optimization problem posed on its solution set without modifying its value and its optimal set. A constraint
is saturated in a given linear optimization problem when it is binding at the optimal set. Saturation is a property related
with the preservation of the value and the optimal set under the elimination of the given constraint, phenomena which can
be seen as weaker forms of excess information in linear optimization problems. We say that an inequality of a given linear
inequality system is uniformly saturated when it is saturated for any solvable linear optimization problem posed on its solution
set. This paper characterizes the uniform saturated inequalities and other related classes of inequalities.
This work was supported by the MCYT of Spain and FEDER of UE, Grant BFM2002-04114-C02-01. 相似文献
36.
37.
G. Kortüm und V. Valent 《Colloid and polymer science》1979,257(9):1012
Ohne Zusammenfassung 相似文献
38.
Plants interact with microbial polysaccharides 总被引:5,自引:0,他引:5
39.
Let Q be a quasigroup. For \(\alpha ,\beta \in S_Q\) let \(Q_{\alpha ,\beta }\) be the principal isotope \(x*y = \alpha (x)\beta (y)\). Put \(\mathbf a(Q)= |\{(x,y,z)\in Q^3;\) \(x(yz)) = (xy)z\}|\) and assume that \(|Q|=n\). Then \(\sum _{\alpha ,\beta }\mathbf a(Q_{\alpha ,\beta })/(n!)^2 = n^2(1+(n-1)^{-1})\), and for every \(\alpha \in S_Q\) there is \(\sum _\beta \mathbf a(Q_{\alpha ,\beta })/n! = n(n-1)^{-1}\sum _x(f_x^2-2f_x+n)\ge n^2\), where \(f_x=|\{y\in Q;\) \( y = \alpha (y)x\}|\). If G is a group and \(\alpha \) is an orthomorphism, then \(\mathbf a(G_{\alpha ,\beta })=n^2\) for every \(\beta \in S_Q\). A detailed case study of \(\mathbf a(G_{\alpha ,\beta })\) is made for the situation when \(G = \mathbb Z_{2d}\), and both \(\alpha \) and \(\beta \) are “natural” near-orthomorphisms. Asymptotically, \(\mathbf a(G_{\alpha ,\beta })>3n\) if G is an abelian group of order n. Computational results: \(\mathbf a(7) = 17\) and \(\mathbf a(8) \le 21\), where \(\mathbf a(n) = \min \{\mathbf a(Q);\) \( |Q|=n\}\). There are also determined minimum values for \(\mathbf a(G_{\alpha ,\beta })\), G a group of order \(\le 8\). 相似文献
40.
Valentín Valero Hermenegilda Macià 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(1):69-82
Timed-arc Petri nets (TAPNs) are a timed extension of Petri nets where tokens are assigned an age indicating the time elapsed from its creation, and PT-arcs (place to transition arcs) are labelled with time intervals that are used to restrict the age of the tokens that can be used to fire the adjacent transition. This is a rather pathological model, as reachability is undecidable, whereas some other known properties of Petri nets, like boundedness, coverability and even termination, are decidable. This article focuses on the problem of detecting dead transitions, i.e. transitions that can be removed from the model since they can never become enabled. We prove that this problem is decidable for TAPNs with natural times, and we present an algorithm that can be used to find dead transitions in the particular case of 1-safe TAPNs. 相似文献
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