31,938 research outputs found
Colloidal hard-rod fluids near geometrically structured substrates
Density functional theory is used to study colloidal hard-rod fluids near an
individual right-angled wedge or edge as well as near a hard wall which is
periodically patterned with rectangular barriers. The Zwanzig model, in which
the orientations of the rods are restricted to three orthogonal orientations
but their positions can vary continuously, is analyzed by numerical
minimization of the grand potential. Density and orientational order profiles,
excess adsorptions, as well as surface and line tensions are determined. The
calculations exhibit an enrichment [depletion] of rods lying parallel and close
to the corner of the wedge [edge]. For the fluid near the geometrically
patterned wall, complete wetting of the wall -- isotropic liquid interface by a
nematic film occurs as a two-stage process in which first the nematic phase
fills the space between the barriers until an almost planar isotropic --
nematic liquid interface has formed separating the higher-density nematic fluid
in the space between the barriers from the lower-density isotropic bulk fluid.
In the second stage a nematic film of diverging film thickness develops upon
approaching bulk isotropic -- nematic coexistence.Comment: 9 pages, 9 figure
Momentum Kick Model Description of the Ridge in (Delta-phi)-(Delta eta) Correlation in pp Collisions at 7 TeV
The near-side ridge structure in the (Delta phi)-(Delta eta) correlation
observed by the CMS Collaboration for pp collisions at 7 TeV at LHC can be
explained by the momentum kick model in which the ridge particles are medium
partons that suffer a collision with the jet and acquire a momentum kick along
the jet direction. Similar to the early medium parton momentum distribution
obtained in previous analysis for nucleus-nucleus collisions at 0.2 TeV, the
early medium parton momentum distribution in pp collisions at 7 TeV exhibits a
rapidity plateau as arising from particle production in a flux tube.Comment: Talk presented at Workshop on High-pT Probes of High-Density QCD at
the LHC, Palaiseau, May 30-June2, 201
Semantic Context Forests for Learning-Based Knee Cartilage Segmentation in 3D MR Images
The automatic segmentation of human knee cartilage from 3D MR images is a
useful yet challenging task due to the thin sheet structure of the cartilage
with diffuse boundaries and inhomogeneous intensities. In this paper, we
present an iterative multi-class learning method to segment the femoral, tibial
and patellar cartilage simultaneously, which effectively exploits the spatial
contextual constraints between bone and cartilage, and also between different
cartilages. First, based on the fact that the cartilage grows in only certain
area of the corresponding bone surface, we extract the distance features of not
only to the surface of the bone, but more informatively, to the densely
registered anatomical landmarks on the bone surface. Second, we introduce a set
of iterative discriminative classifiers that at each iteration, probability
comparison features are constructed from the class confidence maps derived by
previously learned classifiers. These features automatically embed the semantic
context information between different cartilages of interest. Validated on a
total of 176 volumes from the Osteoarthritis Initiative (OAI) dataset, the
proposed approach demonstrates high robustness and accuracy of segmentation in
comparison with existing state-of-the-art MR cartilage segmentation methods.Comment: MICCAI 2013: Workshop on Medical Computer Visio
Robust L2 - L∞ filtering for a class of dynamical systems with nonhomogeneous Markov jump process
This paper investigates the problem of robust L2 - L∞ filtering for a class of dynamical systems with nonhomogeneous Markov jump process. The time-varying transition probabilities which evolve as a nonhomogeneous jump process are described by a polytope, and parameter-dependent and mode-dependent Lyapunov function is constructed for such system, and then a robust L2 -L8 filter is designed which guarantees that the resulting error dynamic system is robustly stochasticallystable and satisfies a prescribed L2 - L∞ performance index. A numerical example is given to illustrate the effectiveness of the developed techniques
Isolation and Characterization of Cypermethrin Degrading Bacteria Screened from Contaminated Soil
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