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Photometric modeling of a cometary nucleus: taking Hapke modeling to the limit
Diffusion and Transport Coefficients in Synthetic Opals
Opals are structures composed of the closed packing of spheres in the size
range of nano-to-micro meter. They are sintered to create small necks at the
points of contact. We have solved the diffusion problem in such structures. The
relation between the diffusion coefficient and the termal and electrical
conductivity makes possible to estimate the transport coefficients of opal
structures. We estimate this changes as function of the neck size and the
mean-free path of the carriers. The theory presented is also applicable to the
diffusion problem in other periodic structures.Comment: Submitted to PR
A Note On Fixed-point Theorems
In an earlier note, S. P. Singh gave an extension of a theorem of Brosowski in a normed linear space setting. Variants of this theorem are considered in the context of strictly convex, reflexive, and inner product spaces. © 1982
Visualization of flows in a motored rotary combustion engine using holographic interferometry
The use of holographic interferometry to view the small- and large-scale flow field structures in the combustion chamber of a motored Wankel engine assembly is described. In order that the flow patterns of interest could be observed, small quantities of helium were injected with the intake air. Variation of the air flow patterns with engine speed, helium flow rate, and rotor position are described. The air flow at two locations within the combustion chamber was examined using this technique
Coarse-grained protein-protein stiffnesses and dynamics from all-atom simulations
Large protein assemblies, such as virus capsids, may be coarse-grained as a
set of rigid domains linked by generalized (rotational and stretching) harmonic
springs. We present a method to obtain the elastic parameters and overdamped
dynamics for these springs from all-atom molecular dynamics simulations of one
pair of domains at a time. The computed relaxation times of this pair give a
consistency check for the simulation, and (using a fluctuation-dissipation
relationship) we find the corrective force needed to null systematic drifts. As
a first application we predict the stiffness of an HIV capsid layer and the
relaxation time for its breathing mode.Comment: 4 pages, 2 tables, 1 figure; v2: fixed a simulation to get much
better agreement with experiment; v3: resolved issues in diffusion results,
submitted to PR
A z=0.9 supercluster of X-ray luminous, optically-selected, massive galaxy clusters
We report the discovery of a compact supercluster structure at z=0.9. The
structure comprises three optically-selected clusters, all of which are
detected in X-rays and spectroscopically confirmed to lie at the same redshift.
The Chandra X-ray temperatures imply individual masses of ~5x10^14 Msun. The
X-ray masses are consistent with those inferred from optical--X-ray scaling
relations established at lower redshift. A strongly-lensed z~4 Lyman break
galaxy behind one of the clusters allows a strong-lensing mass to be estimated
for this cluster, which is in good agreement with the X-ray measurement.
Optical spectroscopy of this cluster gives a dynamical mass in good agreement
with the other independent mass estimates. The three components of the
RCS2319+00 supercluster are separated from their nearest neighbor by a mere <3
Mpc in the plane of the sky and likely <10 Mpc along the line-of-sight, and we
interpret this structure as the high-redshift antecedent of massive (~10^15
Msun) z~0.5 clusters such as MS0451.5-0305.Comment: ApJ Letters accepted. 5 pages in emulateapj, 3 figure
Band Crossing and Novel Low-Energy Behaviour in a Mean Field Theory of a Three-Band Model on a Cu--O lattice
We study correlation effects in a three-band extended Hubbard model of Cu --
O planes within the 1/N mean field approach, in the infinite U limit. We
investigate the emerging phase diagram and discuss the low energy scales
associated with each region. With increasing direct overlap between oxygen
orbitals, , the solution displays a band crossing which, for an
extended range of parameters, lies close to the Fermi level. In turn this leads
to the nearly nested character of the Fermi surface and the resulting linear
temperature dependence of the quasi-particle relaxation rate for sufficiently
large T. We also discuss the effect of band crossing on the optical
conductivity and comment on the possible experimental relevance of our
findings.Comment: 12 pages, Latex-Revtex, 6 PostScript figures. Submitted to Phys. Rev.
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