3,814 research outputs found
A Program In Urban Hydrology, Part Ii: An Evaluation Of Rainfall-Runoff For Small Urbanized Watersheds And The Effect Of Urbanization On Runoff
Estimates of electronic interaction parameters for LaO compounds (=Ti-Ni) from ab-initio approaches
We have analyzed the ab-initio local density approximation band structure
calculations for the family of perovskite oxides, LaO with =Ti-Ni
within a parametrized nearest neighbor tight-binding model and extracted
various interaction strengths. We study the systematics in these interaction
parameters across the transition metal series and discuss the relevance of
these in a many-body description of these oxides. The results obtained here
compare well with estimates of these parameters obtained via analysis of
electron spectroscopic results in conjunction with the Anderson impurity model.
The dependence of the hopping interaction strength, t, is found to be
approximately .Comment: 18 pages; 1 tex file+9 postscript files (appeared in Phys Rev B Oct
15,1996
Extended Self-similarity in Kinetic Surface Roughening
We show from numerical simulations that a limited mobility solid-on-solid
model of kinetically rough surface growth exhibits extended self-similarity
analogous to that found in fluid turbulence. The range over which
scale-independent power-law behavior is observed is significantly enhanced if
two correlation functions of different order, such as those representing two
different moments of the difference in height between two points, are plotted
against each other. This behavior, found in both one and two dimensions,
suggests that the `relative' exponents may be more fundamental than the
`absolute' ones.Comment: 4 pages, 4 postscript figures included (some changes made according
to referees' comments. accepted for publication in PRE Rapid Communication
Dissipationless transport in low density bilayer systems
In a bilayer electronic system the layer index may be viewed as the
z-component of an isospin-1/2. An XY isospin-ordered ferromagnetic phase was
observed in quantum Hall systems and is predicted to exist at zero magnetic
field at low density. This phase is a superfluid for opposite currents in the
two layers. At B=0 the system is gapless but superfluidity is not destroyed by
weak disorder. In the quantum Hall case, weak disorder generates a random gauge
field which probably does not destroy superfluidity. Experimental signatures
include Coulomb drag and collective mode measurements.Comment: 4 pages, no figures, submitted to Phys. Rev. Let
VLA OH and H I Zeeman Observations of the NGC 6334 Complex
We present OH and H I Zeeman observations of the NGC 6334 complex taken with
the Very Large Array. The OH absorption profiles associated with the complex
are relatively narrow (del-v_FWHM ~ 3 km s^1) and single-peaked over most of
the sources. The H I absorption profiles contain several blended velocity
components. One of the compact continuum sources in the complex (source A) has
a bipolar morphology. The OH absorption profiles toward this source display a
gradient in velocity from the northern continuum lobe to the southern continuum
lobe; this velocity gradient likely indicates a bipolar outflow of molecular
gas from the central regions to the northern and southern lobes. Magnetic
fields of the order of 200 microG have been detected toward three discrete
continuum sources in the complex. Virial estimates suggest that the detected
magnetic fields in these sources are of the same order as the critical magnetic
fields required to support the molecular clouds associated with the sources
against gravitational collapse.Comment: 14 pages, 9 postscript figures, accepted for publication in the
Astrophysical Journal (ApJ), tentatively scheduled for vol. 533, Apr. 20,
2000; also available at
http://www.pa.uky.edu/~sarma/RESEARCH/aps_research.htm
Trio-One: Layering Uncertainty and Lineage on a Conventional DBMS
Trio is a new kind of database system that supports data, uncertainty, and lineage in a fully integrated manner. The first Trio prototype, dubbed Trio-One, is built on top of a conventional DBMS using data and query translation techniques together with a small number of stored procedures. This paper describes Trio-One's translation scheme and system architecture, showing how it efficiently and easily supports the Trio data model and query language
Temperature independent band structure of WTe2 as observed from ARPES
Extremely large magnetoresistance (XMR), observed in transition metal
dichalcogendies, WTe, has attracted recently a great deal of research
interests as it shows no sign of saturation up to the magnetic field as high as
60 T, in addition to the presence of type-II Weyl fermions. Currently, there
has been a lot of discussion on the role of band structure changes on the
temperature dependent XMR in this compound. In this contribution, we study the
band structure of WTe using angle-resolved photoemission spectroscopy
(ARPES) and first-principle calculations to demonstrate that the temperature
dependent band structure has no substantial effect on the temperature dependent
XMR as our measurements do not show band structure changes on increasing the
sample temperature between 20 and 130 K. We further observe an electronlike
surface state, dispersing in such a way that it connects the top of bulk
holelike band to the bottom of bulk electronlike band. Interestingly, similar
to bulk states, the surface state is also mostly intact with the sample
temperature. Our results provide invaluable information in shaping the
mechanism of temperature dependent XMR in WTe.Comment: 7 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1705.0721
Regge behaviour of distribution functions and t and x-evolutions of gluon distribution function at low-x
In this paper t and x-evolutions of gluon distribution function from
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi(DGLAP) evolution equation in leading
order(LO) at low-x, assuming the Regge behaviour of quark and gluon at this
limit, are presented. We compare our results of gluon distribution function
with MRST 2001, MRST 2004 and GRV '98 parameterizations and show the
compatibility of Regge behaviour of quark and gluon distribution functions with
perturbative quantum chromodynamics(PQCD) at low-x. We also discuss the
limitations of Taylor series expansion method used earlier to solve DGLAP
evolution equations, in the Regge behaviour of distribution functions.Comment: 19 pages, 7 figure
Carrier relaxation due to electron-electron interaction in coupled double quantum well structures
We calculate the electron-electron interaction induced energy-dependent
inelastic carrier relaxation rate in doped semiconductor coupled double quantum
well nanostructures within the two subband approximation at zero temperature.
In particular, we calculate, using many-body theory, the imaginary part of the
full self-energy matrix by expanding in the dynamically RPA screened Coulomb
interaction, obtaining the intrasubband and intersubband electron relaxation
rates in the ground and excited subbands as a function of electron energy. We
separate out the single particle and the collective excitation contributions,
and comment on the effects of structural asymmetry in the quantum well on the
relaxation rate. Effects of dynamical screening and Fermi statistics are
automatically included in our many body formalism rather than being
incorporated in an ad-hoc manner as one must do in the Boltzman theory.Comment: 26 pages, 5 figure
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