187 resultados para Structure of Opportunity


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Within the framework of a nonlinear chiral Lagrangian we explore the nontrivial nature of f(0)(600) and f(0)(1370) in terms of quarkonium, tetraquark and gluonium components. The mass constraints are obtained and the strong and radiative partial widths are calculated to demonstrate and discriminate these components. The static properties of f(0)(1500) and glueball are also studied. Our results are confronted with the experimental and theoretical data available as well as the upcoming measurements. (C) 2010 Elsevier B.V. All rights reserved.

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By using phi-mapping topological current theory and gauge potential decomposition, we discuss the self-dual equation and its solution in the SU(N) Dunne-Jackiw-Pi-Trugenberger model and obtain a new concrete self-dual equation with a 6 function. For the SU(3) case, we obtain a new self-duality solution and find the relationship between the soliton solution and topological number which is determined by the Hopf index and Brouwer degree of phi-mapping. In our solution, the flux of this soliton is naturally quantized.

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We measured the total reaction cross sections of N-12 in Si at 36.2 MeV/u. using Radioactive Ion Beam Line in Lanzhou (RIBLL) with a new method. The reaction target was installed at the intermediate focusing point T1 at RIBLL. This scheme allows us to identify particles before and after the reaction target unambiguously. The total reaction cross section (1760 +/- 78mb) of N-12 in Si is obtained. Assuming that N-12 consists of a core C-11 plus one halo proton, the excitation function of N-12 on the Si and C targets is calculated with the Glauber model and the Fermi-Fermi density distributions. It can fit the experimental data very well. A large diffusion of the protons density distribution supports the halo structure for N-12.

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The electrocatalysts of Pt/C, PtRu/C and Ru/C were prepared by the impregnation method. The facet characterization, the dispersion and the particle size for the catalysts were determined by means of X-ray diffraction and transmission electron microscopy. X-ray photoelectron spectroscopy was also used to analyze the state and the valency of the noble metals. The results show that the particle size was in nanometer range and the binary metals have come into being an alloy. The platinum in the catalysts existed in zero valency. The valency of the ruthenium on the surface is different from that in the body, while the ruthenium on the surface existed in oxide-form. PtRu/C and Pt/C are of good activity to the electrooxidation of hydrogen except Ru/C. PtRu/C is more tolerant of CO than Pt/C, and CO is only adsorbed on Pt.

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A new trimer from the reaction of ageratochromene [1] (6,7-dimethoxy-2,2-dimethyl-1-benzopyran) with anhydrous aluminum chloride was shown to be 3,4-dihydro-6,7-dimethoxy-2,2-dimethyl-3-(6',7'-dimethoxy-2',2'-di-methyl-2H-1-benzopyran-4'-yl)-4-(3" 4"-dihydro-6", 7"-dimethoxy-2",2"-dimethyl-2H-1-benzopyran-3"-yl)-2H-1-benzopyran. Its structure was confirmed by NMR (H-1, C-13, DEPT-135. COSY, HMBC, HSQC, TOCSY and NOESY), IR, mass spectra and elemental analysis. Copyright (C) 2002 John Wiley Sons, Ltd.

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We present an analysis of extensive nutrient data sets from two river-dominated coastal ecosystems, the northern Adriatic Sea and the northern Gulf of Mexico, demonstrating significant changes in surface nutrient ratios over a period of 30 years. The silicon:nitrogen ratios have decreased, indicating increased potential for silicon limitation. The nitrogen:phosphorus and the silicon:phosphorus ratios have also changed substantially, and the coastal nutrient structures have become more balanced and potentially less limiting for phytoplankton growth. It is likely that net phytoplankton productivity increased under these conditions and was accompanied by increasing bottom water hypoxia and major changes in community species composition. These findings support the hypothesis that increasing coastal eutrophication to date may be associated with stoichiometric nutrient balance, due to increasing potential for silicon limitation and decreasing potential for nitrogen and phosphorus limitation. On a worldwide basis, coastal ecosystems adjacent to rivers influenced by anthropogenic nutrient loads may experience similar alterations.

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A series of complex perovskite solid solutions of Ba[(Mg1-xCdx)(0.33)Nb-0.67]O-3 have been synthesized by the columbite method. Detailed Rietveld refinement of their X-ray diffraction data show that Ba[(Mg1-xCdx)0(.33)Nb(0.67)]O-3 has an order trigonal structure. The ordering degree as determined by the B-site occupancies increases with the partial substitution of Cd for Mg.

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We studied the self-assembly of polydisperse diblock copolymers under various confined states by Monte Carlo simulation. When the copolymers were confined within two parallel walls, it was found that the ordered strip structures appeared alternately with the increase in wall width. Moreover, the wall width at which the ordered structure appeared tended to increase with an increase in the polydispersity index (PDI). On the other hand, the simulation results showed that the copolymers were likely to form ordered concentric strip structures when they were confined within a circle wall.

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New low dimensional polymeric haloplumbate(II) complexes of the dication of (4,4'-bis(imidazolyl-ylmethyl)biphenyl) were synthesised and their crystal structures determined. Complex 1, [Pb4Br12(C40H40N8)], has cis-edge-shared, octahedral, lead bromide double chains. In compound 2 [Pb4Cl12(C40H40N8)]center dot H2O, the inorganic chains are corner-shared, square pyramidal chains of lead chloride. In both compounds the organic ammoniums form regular layers that alternate with the inorganic chains.

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The multiphase morphology of high impact polypropylene (hiPP), which is a reactor blend of polypropylene (PP) with ethylene-propylene copolymer, was investigated by transmission electron microscopy, selected area electron diffraction, atomic force microscopy, and field-emission scanning electron microscopy techniques in conjunction with an analysis of the hiPP composition and chain structure based on solvent fractionation, C-13-NMR, and differential scanning calorimetry measurements.

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A new polyoxotungstate complex [Na-2(H2O)(8)][Na-8(H2O)(20)][Cu(en)(2)][W12O42] center dot 3 H2O (1) (en = ethylenediamine) has been synthesized in aqueous solution and characterized by elemental analysis, IR spectroscopy and TG analysis, together with a single crystal X-ray diffraction study. In compound 1, the Cu(en)(2)(2+) complex cation links the [W12O42](12-) anions to form a I D chain, and the ID chains are further interconnected with Na-8(H2O)(20)(8+) and Na-2(H2O)(8)(2+) cations to construct a new 3D framework.

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Bond distances, vibrational frequencies, dissociation energies, electron affinities, ionization potentials and dipole moments of the title molecules in neutral and charged ions were studied by use of density functional method. Ground states for each molecule were assigned. The calculated bond distance decreases with the increasing of atomic number of 4d metals, reaches minimum at RhS, then increases. For cationic molecules, the calculated bond distance decreases to the minimum at MoS+, then increases. The calculated vibrational frequency decreases from YS(YS+) to PdS(PdS+) for both neutral and cationic molecules. The bond ionic character decreases from YS(YS+) to PdS(PdS+) for neutral and cationic molecules. The bonding patterns are discussed and compared with the available studies.