882,790 research outputs found
Baryon Binding Energy in Sakai-Sugimoto Model
The binding energy of baryon has been studied in the dual
string theory with a black hole interior. In this picture baryon is constructed
of a brane vertex wrapping on and fundamental strings
connected to it. Here, we calculate the baryon binding energy in Sakai-Sugimoto
model with a in which the supersymmetry is completely
broken. Also we check the dependence of the baryon binding energy. We
believe that this model represents an accurate description of baryons due to
the existence of Chern-Simones coupling with the gauge field on the brane. We
obtain an analytical expression for the baryon binding energy . In that case we
plot the baryon binding energy in terms of radial coordinate. Then by using the
binding energy diagram, we determine the stability range for baryon
configuration. And also the position and energy of the stable equilibrium point
is obtained by the corresponding diagram. Also we plot the baryon binding
energy in terms of temperature and estimate a critical temperature in which the
baryon would be dissociated.Comment: 14 pages, 1 fi
Study of fragmentation using clusterization algorithm with realistic binding energies
We here study fragmentation using \emph{simulated annealing clusterization
algorithm} (SACA) with binding energy at a microscopic level. In an earlier
version, a constant binding energy (4 MeV/nucleon) was used. We improve this
binding energy criterion by calculating the binding energy of different
clusters using modified Bethe-Weizs\"{a}cker mass (BWM) formula. We also
compare our calculations with experimental data of ALADiN group. Nearly no
effect is visible of this modification
Energy scaling law for nanostructured materials
The equilibrium binding energy is an important factor in the design of
materials and devices. However, it presents great computational challenges for
materials built up from nanostructures. Here we investigate the binding-energy
scaling law from first-principles calculations. We show that the equilibrium
binding energy per atom between identical nanostructures can scale up or down
with nanostructure size. From the energy scaling law, we predict finite
large-size limits of binding energy per atom. We find that there are two
competing factors in the determination of the binding energy: Nonadditivities
of van der Waals coefficients and center-to-center distance between
nanostructures. To uncode the detail, the nonadditivity of the static multipole
polarizability is investigated. We find that the higher-order multipole
polarizability displays ultra-strong intrinsic nonadditivity, no matter if the
dipole polarizability is additive or not.Comment: 13 pages, 4 figures, 7 table
The Okamoto-Nolen-Schiffer anomaly without rho-omega mixing
We examine the effect of isospin-violating meson-nucleon coupling constants
and of - mixing on the binding-energy differences of mirror nuclei
in a model that possesses no contribution from - mixing. The
He-H binding-energy difference is computed in a nonrelativistic
approach using a realistic wave function. We find the He-H
binding-energy difference very sensitive to the short-distance behavior of the
nucleon-nucleon potential. We conclude that for the typically hard Bonn form
factors such models can not account for the observed binding-energy difference
in the three-nucleon system. For the medium-mass region (A=15--41) the
binding-energy differences of mirror nuclei are computed using a relativistic
mean-field approximation to the Walecka model. We obtain large binding-energy
differences---of the order of several hundred keV---arising from the
pseudoscalar sector. Two effects are primarily responsible for this new
finding: a) the inclusion of isospin breaking in the pion-nucleon coupling
constant, and b) the in-medium enhancement of the small components of the
bound-state wave functions. We look for off-shell ambiguities in these results
and find them to be large.Comment: 19 LaTeX pages and 2 postscript figures. Revisions/additions:
Manuscript now includes a treatment of the binding-energy difference in the
three-nucleon system as well as a study of possible off-shell ambiguities in
the binding-energy differences of (A=15-41) mirror nucle
Effect of shell thickness on exciton and biexciton binding energy of a ZnSe/ZnS core/shell quantum dot
The exciton and biexciton binding energy have been studied for a ZnSe/ZnS
core/shell quantum dot using WKB (Wentzel-Kramers-Brillouin) approximation. The
exciton binding energy increases for small shell thickness and for large
thickness, the binding energy again starts decreasing. A similar result is
obtained for biexcitons where for thicker shells, the biexciton attains
antibonding.Comment: 5 Figure
Genome-wide organization of eukaryotic pre-initiation complex is influenced by nonconsensus protein-DNA binding
Genome-wide binding preferences of the key components of eukaryotic
pre-initiation complex (PIC) have been recently measured with high resolution
in Saccharomyces cerevisiae by Rhee and Pugh (Nature (2012) 483:295-301). Yet
the rules determining the PIC binding specificity remain poorly understood. In
this study we show that nonconsensus protein-DNA binding significantly
influences PIC binding preferences. We estimate that such nonconsensus binding
contribute statistically at least 2-3 kcal/mol (on average) of additional
attractive free energy per protein, per core promoter region. The predicted
attractive effect is particularly strong at repeated poly(dA:dT) and
poly(dC:dG) tracts. Overall, the computed free energy landscape of nonconsensus
protein-DNA binding shows strong correlation with the measured genome-wide PIC
occupancy. Remarkably, statistical PIC binding preferences to both
TFIID-dominated and SAGA-dominated genes correlate with the nonconsensus free
energy landscape, yet these two groups of genes are distinguishable based on
the average free energy profiles. We suggest that the predicted nonconsensus
binding mechanism provides a genome-wide background for specific promoter
elements, such as transcription factor binding sites, TATA-like elements, and
specific binding of the PIC components to nucleosomes. We also show that
nonconsensus binding influences transcriptional frequency genome-wide
Binding of Nucleobases with Single-Walled Carbon Nanotubes
We have calculated the binding energy of various nucleobases (guanine (G),
adenine (A), thymine (T) and cytosine (C)) with (5,5) single-walled carbon
nanotubes (SWNTs) using ab-initio Hartre-Fock method (HF) together with force
field calculations. The gas phase binding energies follow the sequence G A
T C. We show that main contribution to binding energy comes from
van-der Wall (vdW) interaction between nanotube and nucleobases. We compare
these results with the interaction of nucleobases with graphene. We show that
the binding energy of bases with SWNTs is much lower than the graphene but the
sequence remains same. When we include the effect of solvation energy
(Poisson-Boltzman (PB) solver at HF level), the binding energy follow the
sequence G T A C , which explains the experiment\cite{zheng}
that oligonucleotides made of thymine bases are more effective in dispersing
the SWNT in aqueous solution as compared to poly (A) and poly (C). We also
demonstrate experimentally that there is differential binding affinity of
nucleobases with the single-walled carbon nanotubes (SWNTs) by directly
measuring the binding strength using isothermal titration (micro) calorimetry.
The binding sequence of the nucleobases varies as thymine (T) adenine (A)
cytosine (C), in agreement with our calculation.Comment: 7 pages, 6 figure
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