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911.
Ysaías J. Alvarado Néstor Cubillán María G. Leal Paola H. Labarca Elba Michelena Yovani Marrero Ponce 《Journal of solution chemistry》2007,36(9):1139-1155
The values of electronic polarizability of quinoline and isoquinoline in extremely diluted liquid solution are reported in this paper. These were obtained by means of three new strategies based on UV-visible-NIR spectroscopy, the Kramers-Krönig relations, high precision densitometry and high exactitude refractometry, which are called here Arakawa’s Approximation (AA), Optical Substractive Approximation (OSA) and Optical Differential Approximation (ODA). In general the static electronic polarizability values of solute molecules obtained by ODA and OSA are in excellent agreement with the reported theoretical values at the Density Functional Theory (DFT) level and the Atom monopole-dipole model, but strong discrepancies were observed with the experimental values previously reported for quinoline and isoquinoline using refractometric and electro-optic methods. These differences were interpreted and analyzed in terms of dielectric intermolecular forces, resonant and pre-resonant effects. The AA method is shown to fail in predicting the polarizability of the quinoline and isoquinoline molecules. 相似文献
912.
Jeff Edmonds 《Discrete and Computational Geometry》2008,39(4):747-765
We give a new algorithm for enumerating all possible embeddings of a metric space (i.e., the distances between every pair
within a set of n points) into ℝ2 Cartesian space preserving their l
∞ (or l
1) metric distances. Its expected time is
(i.e., within a poly-log of the size of the input) beating the previous
algorithm. In contrast, we prove that detecting l
∞3 embeddings is NP-complete. The problem is also NP-complete within l
12 or l
∞2 with the added constraint that the locations of two of the points are given or alternatively that the two dimensions are
curved into a three-dimensional sphere. We also refute a compaction theorem by giving a metric space that cannot be embedded
in l
∞3; however, it can be embedded if any single point is removed.
This research is partially supported by NSERC grants. I would like to thank Steven Watson for his extensive help on this paper. 相似文献
913.
Khaled Mehrez 《Integral Transforms and Special Functions》2017,28(2):130-144
In this paper, our aim is to show some mean value inequalities for the Wright function, such as Turán-type inequalities, Lazarevi?-type inequalities, Wilker-type inequalities and Redheffer-type inequalities. Moreover, we prove monotonicity of ratios for sections of series of Wright functions, the result is also closely connected with Turán-type inequalities. In the end of the paper, we present some other inequalities for the Wright function. 相似文献
914.
It is known that characters of irreducible representations of finite Lie algebras can be obtained using the Weyl character formula including Weyl group summations which make actual calculations almost impossible except for a few Lie algebras of lower rank. By starting from the Weyl character formula, we show that these characters can be re-expressed without referring to Weyl group summations. Some useful technical points are given in detail for the instructive example of G2 Lie algebra. 相似文献
915.
The Erd?s–Gallai Theorem states that every graph of average degree more than contains a path of order for . In this paper, we obtain a stability version of the Erd?s–Gallai Theorem in terms of minimum degree. Let be a connected graph of order and be disjoint paths of order respectively, where , , and . If the minimum degree , then except several classes of graphs for sufficiently large , which extends and strengths the results of Ali and Staton for an even path and Yuan and Nikiforov for an odd path. 相似文献
916.
Stability for parametric implicit vector equilibrium problems 总被引:6,自引:0,他引:6
In this paper, we consider a class of parametric implicit vector equilibrium problems in Hausdorff topological vector spaces where a mapping f and a set K are perturbed by parameters and λ, respectively. We establish sufficient conditions for the upper semicontinuity and lower semicontinuity of the solution set mapping S:Λ1×Λ2→2X for such parametric implicit vector equilibrium problems. 相似文献
917.
Shuo Qiao 《Journal of organometallic chemistry》2011,696(14):2746-2753
Reaction of quinolin-8-amine with 1H-pyrrole-2-carbaldehyde or 5-tert-butyl-1H-pyrrole-2-carbaldehyde catalyzed by HCO2H forms N-((1H-pyrrol-2-yl)methylene)quinolin-8-amine (≡ HL, 3a) or N-((5-tert-butyl-1H-pyrrol-2-yl)methylene)quinolin-8-amine (≡ HL′, 3b). Treatment of 3a and 3b respectively with AlMe3 or AlEt3 in toluene affords corresponding aluminum complexes LAlMe2 (4a), L′AlMe2 (4b) and LAlEt2 (4c). Reaction of 3a and 3b with an equivalent of ZnEt2 in toluene generates L2Zn and L′2Zn, respectively. A related compound N-((1H-pyrrol-2-yl)methylene)-2-(3,5-dimethyl-1H-pyrazol-1-yl)benzenamine (≡ HL″, 7) was prepared by reaction of 2-(3,5-dimethyl-1H-pyrazol-1-yl)benzenamine with 1H-pyrrole-2-carbaldehyde in the presence of HCO2H. Reaction of 7 with AlMe3 gives L″2AlMe (8), and with ZnEt2 yields L″2Zn (9). All new compounds were characterized by NMR spectroscopy and elemental analysis. The structures of complexes 4b, 5b and 8 were additionally characterized by single crystal X-ray diffraction analyses. Complexes 4a-4c, and 8 were proved to be active catalysts for the ring-opening polymerization (ROP) of ?-caprolactone (?-CL) in the presence of BnOH. The kinetic study of the polymerization reactions catalyzed by 4a and 8 was performed. 相似文献
918.
Overweg A. R. Crajé M. W. J. Arends I. W. C. E. van der Kraan A. M. 《Hyperfine Interactions》2002,141(1-4):391-395
Hyperfine Interactions - Mössbauer spectra were recorded at 4.2 K of an FeZSM-5 zeolite that has been treated with nitrogen at 623 K. Changes in the sample environment clearly show the... 相似文献
919.
F. Taneri T. Güneri Z. Aigner O. Berkesi M. Kata 《Journal of Thermal Analysis and Calorimetry》2004,76(2):471-479
γ-Cyclodextrin and dimethyl-β-cyclodextrin were used as solubilizing agents for a very poorly water-soluble drug, an imidazole
derivative antifungal agent, clotrimazole; with the aim of improving the physicochemical properties of the drug. Solid products
were prepared by physical mixing, kneading, precipitation and spray-drying methods in 1:1 and 1:2 drug:cyclodextrin molar
ratios. Drug interactions were studied by thermoanalytical methods such as DSC, DTA, TG and DTG, X-ray diffractometry and
Fourier transformation-infrared spectroscopy. The results demonstrated the formation of inclusion complexes in some products.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
920.
Mohamed Barraa 《Journal of Mathematical Analysis and Applications》2008,347(1):315-322
In this paper we investigate perturbations of the regular spectrum of an upper triangular operator matrix such as acting on a Hilbert space H⊕K. 相似文献