309 research outputs found
Structural and electronic properties of Si (111) and (001) nanowires: A theoretical study
AbstractIn this work, our preliminary theoretical results for the structural and electronic properties of both Si (111) and (100) nanowires, with their lateral surfaces saturated with H or not, are shown. Our results show that, without the saturators, there is the formation of {110} facets to partly release the stress accumulated at lateral surfaces of the nanowires. These facets give rise to states close to the top of valence band and to the bottom of the conduction band that have character arising from both the occupied and empty Si-derived dangling bonds, respectively. Moreover, while the (111) nanowires have a direct band gap, with values within the visible range of the electromagnetic spectra, the (100) ones have an indirect band gap
A class of elliptic systemsinvolving N-functions
AbstractIn this work, we state a result of compactness due to Lions in Orlicz spaces. Wegive an application proving an existence result for a gradient type elliptic systems in ℝN involving N-functions
On an elliptic Kirchhoff-type problem depending on two parameters
In this paper, we consider the Dirichlet problem associated to an elliptic
Kirchhoff-type equation depending on two parameters. Under rather general and
natural assumptions, we prove that, for certain values of the parameters, the
problem has at least three solutions
The Error and Repair Catastrophes: A Two-Dimensional Phase Diagram in the Quasispecies Model
This paper develops a two gene, single fitness peak model for determining the
equilibrium distribution of genotypes in a unicellular population which is
capable of genetic damage repair. The first gene, denoted by ,
yields a viable organism with first order growth rate constant if it
is equal to some target ``master'' sequence . The second
gene, denoted by , yields an organism capable of genetic repair
if it is equal to some target ``master'' sequence . This
model is analytically solvable in the limit of infinite sequence length, and
gives an equilibrium distribution which depends on \mu \equiv L\eps , the
product of sequence length and per base pair replication error probability, and
\eps_r , the probability of repair failure per base pair. The equilibrium
distribution is shown to exist in one of three possible ``phases.'' In the
first phase, the population is localized about the viability and repairing
master sequences. As \eps_r exceeds the fraction of deleterious mutations,
the population undergoes a ``repair'' catastrophe, in which the equilibrium
distribution is still localized about the viability master sequence, but is
spread ergodically over the sequence subspace defined by the repair gene. Below
the repair catastrophe, the distribution undergoes the error catastrophe when exceeds \ln k/\eps_r , while above the repair catastrophe, the
distribution undergoes the error catastrophe when exceeds , where denotes the fraction of deleterious mutations.Comment: 14 pages, 3 figures. Submitted to Physical Review
FATOR DE ASSIMETRIA E DEFORMAÇÕES NEOTECTÔNICAS NA BACIA PARAÍBA, NORDESTE DO BRASIL
Um número crescente de publicações tem sugerido eventos de reativações tectônicas Cenozóicas na Bacia Paraíba, apesar de sua localização em margem passiva. O objetivo deste estudo é contribuir para ampliar esse registro com o uso do FSTT na caracterização tectônica em dois compartimentos morfologicamente distintos dessa bacia. Para isso, aplicou-se o FSTT a partir de MDE-SRTM. Os resultados sugerem dois estilos de deformações tectônicas nesses compartimentos: rúptil a oeste e dúctil a leste
Compactness and existence results in weighted Sobolev spaces of radial functions. Part II: Existence
We prove existence and multiplicity results for finite energy solutions to
the nonlinear elliptic equation where is a radial domain (bounded or
unbounded) and satisfies on if and as
if is unbounded. The potential may be vanishing or unbounded at
zero or at infinity and the nonlinearity may be superlinear or sublinear.
If is sublinear, the case with is also considered.Comment: 29 pages, 8 figure
Hadronic Production of Lambda_c from 600 GeV/c pion, sigma and proton beams
We present data from Fermilab experiment E781 (SELEX) on the hadroproduction
asymmetry for anti-Lambda_c compared to Lambda_c+ as a function of xF and pt2
distributions for Lambda_c+. These data were measured in the same apparatus
using incident pi-, sigma- beams at 600 GeV/c and proton beam at 540 GeV/c. The
asymmetry is studied as a function of xF. In the forward hemisphere with xF >=
0.2 both baryon beams exhibit very strong preference for producing charm
baryons rather than charm antibaryons, while the pion beam asymmetry is much
smaller. In this energy regime the results show that beam fragments play a
major role in the kinematics of Lambda_c formation, as suggested by the leading
quark picture.Comment: 6 pages, 5 figures (postscript), RevTeX, submitted to Phy. Rev. Let
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