12,614 research outputs found
Capture on High Curvature Region: Aggregation of Colloidal Particle Bound to Giant Phospholipid Vesicles
A very recent observation on the membrane mediated attraction and ordered
aggregation of colloidal particles bound to giant phospholipid vesicles (I.
Koltover, J. O. R\"{a}dler, C. R. Safinya, Phys. Rev. Lett. {\bf 82},
1991(1999)) is investigated theoretically within the frame of Helfrich
curvature elasticity theory of lipid bilayer fluid membrane. Since the concave
or waist regions of the vesicle possess the highest local bending energy
density, the aggregation of colloidal beads on these places can reduce the
elastic energy in maximum. Our calculation shows that a bead in the concave
region lowers its energy . For an axisymmetrical dumbbell
vesicle, the local curvature energy density along the waist is equally of
maximum, the beads can thus be distributed freely with varying separation
distance.Comment: 12 pages, 2 figures. REVte
Properties of nuclear matter from macroscopic-microscopic mass formulas
Based on the standard Skyrme energy density functionals together with the
extended Thomas-Fermi approach, the properties of symmetric and asymmetric
nuclear matter represented in two macroscopic-microscopic mass formulas:
Lublin-Strasbourg nuclear drop energy (LSD) formula and Weizs\"acker-Skyrme
(WS*) formula, are extracted through matching the energy per particle of finite
nuclei. For LSD and WS*, the obtained incompressibility coefficients of
symmetric nuclear matter are MeV and MeV,
respectively. The slope parameter of symmetry energy at saturation density is
MeV for LSD and MeV for WS*, respectively, which
is compatible with the liquid-drop analysis of Lattimer and Lim [ApJ.
\textbf{771}, 51 (2013)]. The density dependence of the mean-field isoscalar
and isovector effective mass, and the neutron-proton effective masses splitting
for neutron matter are simultaneously investigated. The results are generally
consistent with those from the Skyrme Hartree-Fock-Bogoliubov calculations and
nucleon optical potentials, and the standard deviations are large and increase
rapidly with density. A better constraint for the effective mass is helpful to
reduce uncertainties of the depth of the mean-field potential.Comment: 5 figures, to appear in Phys. Lett.
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