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231.
232.
The constrained forest problem seeks a minimum-weight spanning forest in an undirected edge-weighted graph such that each tree spans at least a specified number of vertices. We present a greedy heuristic for this NP-hard problem, whose solutions are at least as good as, and often better than, those produced by the best-known 2-approximate heuristic. 相似文献
233.
Substitution inertcis-diaqua CrIII complexes: cis-[(Lx−)CrIII(H2O)2](3−x)+ derived from N-donor ligands (Lx−) viz., bipyridine and 1,10-phenanthroline (x = 0) and N,O-donor ligands viz., nitrilotriacetate and anthranilate N,N-diacetate
(x = 3) titrate as diprotic acids in aqueous solution and enhance the acidity of otherwise weakly acidic boric acid (H3BO3) producing mononuclear and binuclear mixed ligand CrIII-borate complexes: [(L)Cr(H2BO4)]x− and [(L)Cr(BO4)Cr(L)](1−2x)+ respectively through coordination of the H2O and/or OH− ligands, cis-coordinated in the CrIII-complexes on the electron deficient BIII-atom in H3BO3 with release of protons. Deprotonation of the parent CrIII-complexes and their reactions with H3BO3 have been investigated by potentiometric method in aqueous solution,I = 0.1 mol dm−3 (NaNO3) at 25 ±0.1°C. The equilibrium constants have been evaluated by computerized methods and the tentative stoichiometry of the
reactions have been worked out on the basis of the speciation curves 相似文献
234.
235.
Dipak Kesh Debasis Mukherjee A. K. Sarkar A. B. Roy 《Journal of Applied Mathematics and Computing》1998,5(2):295-305
In this study, we have considered a prey-predator model reflecting the predator interference with discrete time delay. This delay is regarded as the lag due to gestation. In absence of delay, the criteria for existence of interior equilibrium and its global stability are derived. By choosing the delay as a bifurcation parameter, we have shown that a Hopf bifurcation may occur when the delay passes its critical value. Finally, we have derived the criteria for stability switches and verified the results through computer simulation. 相似文献
236.
New concepts of fuzzy semi δ-V and fuzzy semi δ-Λ sets were introduced in our work “On fuzzy semi δ-Λ sets and fuzzy semi δ-V sets V-6,” J. Trip. Math. Soc., 6, 81–88 (2004). It was shown that the family of all fuzzy semi δ-V sets forms a fuzzy supra topological space on X denoted by (X, FS
δV
). The aim of this paper is to introduce the concept of fuzzy semi δ-V continuity in a fuzzy δ-V topological space. Finally, some properties, preservation theorems, etc., are studied.
Published in Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 5, pp. 712–717, May, 2008. 相似文献
237.
Photophysical characteristics of capped and uncapped CdS particles have been investigated in aqueous solution. It is seen
that the fluorescence spectrum shifts towards lower energies in the presence of toluene dithiol (TDT) and dimercaptophthalic
acid (DMPA). This shift, which is due to quenching of shallow traps, is more predominant with TDT. Also, the presence of excess
Cd2+ ions at the surface of the CdS particles facilitates the binding of dithiolenes. 相似文献
238.
Based on experimental data, flow regime maps were drawn for different inclination angles, including horizontal and vertical flow. Different empirical equations for the flow regime transitions are proposed that are functions of inclination angle for both upflow and downflow. In general, the flow regimes and their transitions for upflow were similar to those proposed by Duns and Ros for vertical upflow. For downflow, the flow regimes and their transitions conformed more to the Mandhane et al. type of flow regime map. The stratified flow region in downflow was found to be affected appreciably by the angle of inclination. A detailed comparison of the proposed transition equations with a number of flow regime maps is also presented. 相似文献
239.
240.