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61.
Structures of complexes formed in aqueous solutions by some anionic polyelectrolytes (double and single stranded (ds and ss)
DNA, poly(vinyl sulfonate) (PVS), and poly(styrene sulfonate) (PSS)) with a cationic surfactant system consisting of cetyltrimethylammonium
bromide (CTAB) and sodium 3-hydroxy-2-naphthoate (SHN) have been determined using small angle X-ray diffraction. All complexes
are found to have a two-dimensional (2-D) hexagonal structure at low SHN concentrations. Analysis of the diffraction data
shows that the ds DNA—CTAB complex has an intercalated structure, with each DNA strand surrounded by three cylindrical micelles.
On increasing SHN concentration, DNA—CTAB—SHN complexes exhibit a hexagonal-to-lamellar transition, whereas PVS complexes
show a hexagonal → centered rectangular → lamellar transition. PSS complexes show yet another sequence of structures. These
results indicate the significant influence of the chemical nature of the polyelectrolyte on the structure of the complexes. 相似文献
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In the cosmic ray experiments deep underground in the Kolar Gold Mines, a special class of events has been observed, at present
6 in number, characterised by several, (in general 3), charged particles arising from a vertex, either in air or in the thin
material of the detectors, with large opening angles; the vertex is at a distance of around 70–100 cms from the rock wall.
The most plausible interpretation of these events is that they are due to the decay of new, massive and long-lived particles
produced in neutrino collisions inside rock, or through hitherto unknown processes. 相似文献
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Analyses of uranium extracted from South Pacific waters by thein-situ extraction method point to a uniform depth independent value of 1·14 ±0 02 for the U234/U238 activity ratio. This value is also the same, within one standard deviation, as that determined for the N. Pacific, S. Indian and Atlantic waters. 相似文献
67.
Jorge E. P. Monteagudo Geraldo L. Rochocz Paulo L. C. Lage Krishnaswamy Rajagopal 《Fluid Phase Equilibria》2001,190(1-2):1-13
The computation of phase equilibrium for semicontinuous mixtures results in a set of algebraic-functional equations which are commonly solved using the pseudocomponent approach or reducing the order of the functional equations to a set of algebraic equations by means of a Petrov–Galerkin approach. Both approaches can be taken as particular cases of the method of weighed residuals. In order to perform stability analysis of phase equilibrium, the classical tangent plane criterion algorithms can be used as the first approach. There is a lack of functional formulation for the stability criterion in the literature. In some special cases, such as mixtures containing continuous families of heavy-components, a new formulation of the tangent plane criterion is required. In the present work, functional extensions of the Gibbs tangent plane criterion are described. The use of the proposed criteria was exemplified by calculating solid–liquid phase equilibrium of a crude oil containing asphaltenes on titration with a precipitating agent, n-pentane. 相似文献
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