33,705 research outputs found
Analytical studies of in-reactor tests of a nuclear light bulb unit cell
Analytical studies of in-reactor tests of nuclear light bulb unit cell using Pewee, nuclear furnace, and high flux isotope reactor
Analytical studies of nuclear light bulb engine radiant heat transfer and performance characteristics
Analytical model of nuclear light bulb engine radiant heat transfer and engine performance, dynamics and control, heat loads and shutdown characteristic
Liquid sloshing in elastic containers
Coupled oscillations of elastic container partially filled with incompressible liqui
Microscopic calculation of the phonon dynamics of SrRuO compared with LaCuO
The phonon dynamics of the low-temperature superconductor SrRuO
is calculated quantitatively in linear response theory and compared with the
structurally isomorphic high-temperature superconductor LaCuO. Our
calculation corrects for a typical deficit of LDA-based calculations which
always predict a too large electronic -dispersion insufficient to
describe the c-axis response in the real materials. With a more realistic
computation of the electronic band structure the frequency and wavevector
dependent irreducible polarization part of the density response function is
determined and used for adiabatic and nonadiabatic phonon calculations. Our
analysis for SrRuO reveals important differences from the lattice
dynamics of - and -doped cuprates. Consistent with experimental evidence
from inelastic neutron scattering the anomalous doping related softening of the
strongly coupling high-frequency oxygen bond-stretching modes (OBSM) which is
generic for the cuprate superconductors is largely suppressed or completely
absent, respectively, depending on the actual value of the on-site Coulomb
repulsion of the Ru4d orbitals. Also the presence of a characteristic
-mode with a very steep dispersion coupling strongly with the
electrons is missing in SrRuO. Moreover, we evaluate the
possibility of a phonon-plasmon scenario for SrRuO which has been
shown recently to be realistic for LaCuO. In contrast to
LaCuO in SrRuO the very low lying plasmons are
overdamped along the c-axis.Comment: 30 pages, 16 figures, 4 tables, 33 reference
Wind Tunnel Generation of Sinusoidal Lateral and Longitudinal Gusts by Circulation of Twin Parallel Airfoils
A gust generator capable of producing sinusoidal lateral and longitudinal gusts was developed for the purpose of studying the gust response of a model rotor-propeller in a wind tunnel. The gust generator utilized harmonic circulation control of twin parallel airfoils to achieve the harmonic lift variation required for gust generation. The gust generator design, construction, and testing is described. Typical test results are presented in the form of lateral and longitudinal gust perturbation velocities as a function of generator reduced frequency
Studies of nuclear light bulb start-up conditions and engine dynamics
Deep Space Network for two-way communications with unmanned spacecraft at planetary distances - Vol.
Anomalous Metal-Insulator Transition in Filled Skutterudite CeOsSb
Anomalous metal-insulator transition observed in filled skutterudite
CeOsSb is investigated by constructing the effective tight-binding
model with the Coulomb repulsion between f electrons. By using the mean field
approximation, magnetic susceptibilities are calculated and the phase diagram
is obtained. When the band structure has a semimetallic character with small
electron and hole pockets at and H points, a spin density wave
transition with the ordering vector occurs due to the
nesting property of the Fermi surfaces. Magnetic field enhances this phase in
accord with the experiments.Comment: 4 pages, 4 figure
A Tale of Two Theories: Quantum Griffiths Effects in Metallic Systems
We show that two apparently contradictory theories on the existence of
Griffiths-McCoy singularities in magnetic metallic systems [1,2] are in fact
mathematically equivalent. We discuss the generic phase diagram of the problem
and show that there is a non-universal crossover temperature range T* < T < W
where power law behavior (Griffiths-McCoy behavior) is expect. For T<T* power
law behavior ceases to exist due to the destruction of quantum effects
generated by the dissipation in the metallic environment. We show that T* is an
analogue of the Kondo temperature and is controlled by non-universal couplings.Comment: 4 pages, 2 figure
Phase diagram for morphological transitions of wetting films on chemically structured substrates
Using an interface displacement model we calculate the shapes of thin
liquidlike films adsorbed on flat substrates containing a chemical stripe. We
determine the entire phase diagram of morphological phase transitions in these
films as function of temperature, undersaturation, and stripe widthComment: 15 pages, RevTeX, 7 Figure
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