26,309 research outputs found
A model study of cooperative binding of ionic surfactants to oppositely charged flexible polyions
A novel statistical model for the cooperative binding of monomeric ligands to
a linear lattice is developed to study the interaction of ionic surfactant
molecules with flexible polyion chain in dilute solution. Electrostatic binding
of a ligand to a site on the polyion and hydrophobic associations between the
neighboring bound ligands are assumed to be stochastic processes. Ligand
association separated by several lattice points within defined width is
introduced for the flexible polyion. Model calculations by the Monte Carlo
method are carried out to investigate the binding behavior. The hypothesis on
the ligand association and its width on the chain are of importance in
determining critical aggregation concentration and binding isotherm. The
results are reasonable for the interpretations of several surfactant-flexible
polyion binding experiments. The implications of the approach are presented and
discussed.Comment: 11 pages, 9 figure
Evidence for Narrow S=+1 Baryon Resonance in Photo-production from Neutron
The gamma n -> K+ K- n reaction on 12C has been studied by measuring both K+
and K- at forward angles. A sharp baryon resonance peak was observed at 1.54 +-
0.01 GeV with a width smaller than 25 MeV and a Gaussian significance of 4.6
sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can
be interpreted as a molecular meson-baryon resonance or alternatively as an
exotic 5-quark state (uudd{s_bar}) that decays into a K+ and a neutron. The
resonance is consistent with the lowest member of an anti-decuplet of baryons
predicted by the chiral soliton model.Comment: 12 pages, 3 encapsulated postscript figure
Ingredients of nuclear matrix element for two-neutrino double-beta decay of 48Ca
Large-scale shell model calculations including two major shells are carried
out, and the ingredients of nuclear matrix element for two-neutrino double beta
decay are investigated. Based on the comparison between the shell model
calculations accounting only for one major shell (-shell) and those for two
major shells (-shell), the effect due to the excitation across the two
major shells is quantitatively evaluated.Comment: To appear in J. Phys. Soc. Conf. Proc. (ARIS2014); for ver.2, Fig.1
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