347 research outputs found
Mesophases in Nearly 2D Room-Temperature Ionic Liquids
Computer simulations of (i) a [C12mim][Tf2N] film of nanometric thickness
squeezed at kbar pressure by a piecewise parabolic confining potential reveal a
mesoscopic in-plane density and composition modulation reminiscent of
mesophases seen in 3D samples of the same room-temperature ionic liquid (RTIL).
Near 2D confinement, enforced by a high normal load, relatively long aliphatic
chains are strictly required for the mesophase formation, as confirmed by
computations for two related systems made of (ii) the same [C12mim][Tf2N]
adsorbed at a neutral solid surface and (iii) a shorter-chain RTIL
([C4mim][Tf2N]) trapped in the potential well of part i. No in-plane modulation
is seen for ii and iii. In case ii, the optimal arrangement of charge and
neutral tails is achieved by layering parallel to the surface, while, in case
iii, weaker dispersion and packing interactions are unable to bring aliphatic
tails together into mesoscopic islands, against overwhelming entropy and
Coulomb forces. The onset of in-plane mesophases could greatly affect the
properties of long-chain RTILs used as lubricants.Comment: 24 pages 10 figure
2D-Drop model applied to the calculation of step formation energies on a (111) substrate
A model is presented for obtaining the step formation energy for metallic
islands on (111) surfaces from Monte Carlo simulations. This model is applied
to homo (Cu/Cu(111), Ag/Ag(111)) and heteroepitaxy (Ag/Pt(111)) systems. The
embedded atom method is used to represent the interaction between the particles
of the system, but any other type of potential could be used as well. The
formulation can also be employed to consider the case of other single crystal
surfaces, since the higher barriers for atom motion on other surfaces are not a
hindrance for the simulation scheme proposed.Comment: 12 pages, LaTeX2e, 2 included EPS figures, submitted to Surface
Science Subj-clas
Controversy over the pharmacological treatments of storage symptoms in spinal cord injury patients: a literature overview
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Improvements in the M-T relation and mass function and the measured Omega_m through clusters evolution
In this paper, I revisit the constraints obtained by several authors
(Reichart et al. 1999; Eke et al. 1998; Henry 2000) on the estimated values of
Omega_m, n and sigma_8 in the light of recent theoretical developments: 1) new
theoretical mass functions (Sheth & Tormen 1999, Sheth, Mo & Tormen 1999, Del
Popolo 2002b); 2) a more accurate mass-temperature relation, also determined
for arbitrary Omega_m and Omega_{\Lambda} (Voit 2000, Pierpaoli et al. 2001,
Del Popolo 2002a). Firstly, using the quoted improvements, I re-derive an
expression for the X-ray Luminosity Function (XLF), similarly to Reichart et
al. (1999), and then I get some constraints to \Omega_m and n, by using the
ROSAT BCS and EMSS samples and maximum-likelihood analysis. Then I re-derive
the X-ray Temperature Function (XTF), similarly to Henry (2000) and Eke et al.
(1999), re-obtaining the constraints on Omega_m, n, sigma_8. Both in the case
of the XLF and XTF, the changes in the mass function and M-T relation produces
an increase in Omega_m of \simeq 20% and similar results in sigma_8 and n.Comment: 34 pages, 11 encapsulated figures. Accepted by Ap
Nerve sprouting and neurogenic inflammation characterize the neurogenic detrusor overactive bladder of patients no longer responsive to drug therapies.
Correlation between membrane bending and lipidic composition during the sperm acrosomal exocytosis : computational analysis
Fil: Suhaiman, L..Fil: Borioni, J.L..Fil: Ferguson, M..Fil: Belmonte, S..Fil: Del Popolo, M. G.
On the cosmological mass function theory
This paper provides, from one side, a review of the theory of the
cosmological mass function from a theoretical point of view, starting from the
seminal paper of Press & Shechter (1974) to the last developments (Del Popolo &
Gambera (1998, 1999), Sheth & Tormen 1999 (ST), Sheth, Mo & Tormen 2001 (ST1),
Jenkins et al. 2001 (J01), Shet & Tormen 2002 (ST2), Del Popolo 2002a, Yagi et
al. 2004 (YNY)), and from another side some improvements on the multiplicity
function models in literature. ...Comment: Astronomy Reports, in prin
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