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Marija S. ?iri? Milan Lj. Zlatanovi? Mi?a S. Stankovi? Ljubica S. Velimirovi? 《Applied mathematics and computation》2012,218(12):6648-6655
In this paper geodesic mappings of equidistant generalized Riemannian spaces are discussed. It is proved that each equidistant generalized Riemannian space of basic type admits non-trivial geodesic mapping with preserved equidistant congruence. Especially, there exists non-trivial geodesic mapping of equidistant generalized Riemannian space onto equidistant Riemannian space. An example of geodesic mapping of an equidistant generalized Riemannian spaces is presented. 相似文献
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Variation of the total mean curvature of piecewise smooth surfaces in Euclidean 3-spaces under infinitesimal bending is discussed and reduced to a sum of line integrals of a rotation vector field. 相似文献
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Snežana S. Mitić Gordana Ž. Miletić Aleksandra N. Pavlović Snežana B. Tošić Dragan S. Velimirović 《中国化学会会志》2007,54(1):47-54
A kinetic method for the determination of micro quantities of amino acid arginine (Arg) is described in this paper. The catalytic activity of cobalt in the reaction of oxidation of purpurin (1,2,4‐trihydroxy‐antraquinone, PP) by hydrogen peroxide in alkaline buffer solution decreases in the presence of micro quantities of arginine, because of the formation of the complex. Operating conditions for the successful determination of arginine were optimized. The optimized conditions yielded a theoretical detection limit of 1.45 μg mL?1. Kinetic equations are proposed for the investigated process. The interference effects of certain foreign ions and amino acids upon the reaction rate were studied and removed in order to assess the selectivity of the method. The developed procedure was successfully applied to the determination of arginine in various pharmaceutical samples. The typical feature of this procedure is that determination can be carried out at room temperature and in a short analysis time. The newly developed method is simple, inexpensive and efficient for use in the analysis of a large number of samples. 相似文献
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Mića S. Stanković Svetislav M. Minčić Ljubica S. Velimirović 《Czechoslovak Mathematical Journal》2004,54(3):701-715
In this paper we investigate holomorphically projective mappings of generalized Kählerian spaces. In the case of equitorsion holomorphically projective mappings of generalized Kählerian spaces we obtain five invariant geometric objects for these mappings. 相似文献
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Dušan Miljković Smiljana Velimirović János Csanádi Velimir Popsavin 《Journal of carbohydrate chemistry》2013,32(3):457-467
Abstract Some new partially or fully tosylated and/or mesylated 2, 5-anhydro-xylitol derivatives have been prepared in this work. Some of them represent the real optically active intermediates in an attempted synthesis of selected (+)-oxybiotin analogs, while the others, being racemic, serve only as easily available model-intermediates. 相似文献
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Ljubica S. Velimirovi? Svetozar R. Ran?i? 《Applied mathematics and computation》2011,217(9):4612-4619
In this paper we consider a class of toroids generated by a meridian in a shape of quadrangle in an arbitrary position to the axis of revolution.We give geometrical meaning of the non-rigidity condition based on the position of the diagonals of meridian. Special classes of quadrangular meridians (trapezium, parallelogram, deltoid, … ) are discussed. The number of flexible toroids is considered. A tool SurfBend is developed for the rigidity and visualization. 相似文献
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Mića S. Stanković Milan Lj. Zlatanović Ljubica S. Velimirović 《Czechoslovak Mathematical Journal》2010,60(3):635-653
In this paper we define generalized Kählerian spaces of the first kind (\(G_1^K N\)) given by (2.1)–(2.3). For them we consider hollomorphically projective mappings with invariant complex structure. Also, we consider equitorsion geodesic mapping between these two spaces (\(G_1^K N\) and \(G_1^{\bar K} N\)) and for them we find invariant geometric objects. 相似文献
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Summary The possibility of application of gold and palladium as the metal phase of quinhydrone electrodes in coulometric bipotentiometric titrations of bases alone and of some of their two-component mixtures in acetic anhydride was investigated. The effect of activation of these electrodes, by heating in an alcohol flame, on the shape of the titration curve is discussed. The amounts of bases determined were 5.0–10.0 eq. Errors did not exceed ±2%.
Zusammenfassung Die Möglichkeit der Verwendung von Gold und Palladium als Metallphase von Chinhydronelektroden bei coulometrischen bipotentiometrischen Titrationen von Basen allein oder Gemischen zweier Basen in Essigsäureanhydrid wurde untersucht. Der Einfluß der Aktivierung dieser Elektroden durch Glühen in einer Alkoholflamme auf die Form der Titrationskurve wurde diskutiert. Die Mengen der analysierten Basen entsprach 5,0–10,0 Mikroäquivalenten. Die Ermittlungsfehler liegen innerhalb ± 2%.相似文献
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Vesić Nenad O. Velimirović Ljubica S. Stanković Mića S. 《Mediterranean Journal of Mathematics》2016,13(6):4581-4590
Mediterranean Journal of Mathematics - In this paper, we consider equitorsion third type almost geodesic mappings of non-symmetric affine connection spaces. Applying different computational... 相似文献