39,990 research outputs found
Field Effect Transistors on Rubrene Single Crystals with Parylene Gate Insulator
We report on fabrication and characterization of the organic field effect
transistors (OFETs) on the surface of single crystals of rubrene. The parylene
polymer film has been used as the gate insulator. At room temperature, these
OFETs exhibit the p-type conductivity with the field effect mobility up to 1
cm^2/Vs and the on/off ratio ~ 10^4. The temperature dependence of the mobility
is discussed.Comment: 3 page
Sudden Expansion of a One-Dimensional Bose Gas from Power-Law Traps
We analyze free expansion of a trapped one-dimensional Bose gas after a
sudden release from the confining trap potential. By using the stationary phase
and local density approximations, we show that the long-time asymptotic density
profile and the momentum distribution of the gas are determined by the initial
distribution of Bethe rapidities (quasimomenta) and hence can be obtained from
the solutions to the Lieb-Liniger equations in the thermodynamic limit. For
expansion from a harmonic trap, and in the limits of very weak and very strong
interactions, we recover the self-similar scaling solutions known from the
hydrodynamic approach. For all other power-law traps and arbitrary interaction
strengths, the expansion is not self-similar and shows strong dependence of the
density profile evolution on the trap anharmonicity. We also characterize
dynamical fermionization of the expanding cloud in terms of correlation
functions describing phase and density fluctuations.Comment: Final published version with modified title and a couple of other
minor changes. 5 pages, 2 figures, and Supplemental Materia
The impact of evolving labor practices and demographics on U.S. inflation and unemployment
Since the early 1990s, NAIRU estimates have declined and unemployment duration has risen relative to the unemployment rate. These developments may have arisen from the aging of the workforce or practices reducing job turnover. We assess the internal consistency of these hypotheses using simulation methods and test their external consistency using modified NAIRU models. We find that demographics cannot fully account for changes in the NAIRU, consistent with Staiger, Stock, and Watson (2001) and in contrast to Shimer (1998, 2001). Instead, our results attribute shifts in the NAIRU and duration to a combination of shifts in demographics and job turnover.
Flux Penetration in Superconducting Strip with Edge-Indentation
The flux penetration near a semicircular indentation at the edge of a thin
superconducting strip placed in a transverse magnetic field is investigated.
The flux front distortion due to the indentation is calculated numerically by
solving the Maxwell equations with a highly nonlinear law. We find that
the excess penetration, , can be significantly ( 50%) larger than
the indentation radius , in contrast to a bulk supercondutor in the
critical state where . It is also shown that the flux creep tends
to smoothen the flux front, i.e. reduce . The results are in very good
agreement with magneto-optical studies of flux penetration into an
YBaCuO film having an edge defect.Comment: 5 pages, 7 figure
Kinetics of viral self-assembly: the role of ss RNA antenna
A big class of viruses self-assemble from a large number of identical capsid
proteins with long flexible N-terminal tails and ss RNA. We study the role of
the strong Coulomb interaction of positive N-terminal tails with ss RNA in the
kinetics of the in vitro virus self-assembly. Capsid proteins stick to
unassembled chain of ss RNA (which we call "antenna") and slide on it towards
the assembly site. We show that at excess of capsid proteins such
one-dimensional diffusion accelerates self-assembly more than ten times. On the
other hand at excess of ss RNA, antenna slows self-assembly down. Several
experiments are proposed to verify the role of ss RNA antenna.Comment: 4 pages, 3 figures, several experiments are proposed, a new idea of
experiment is adde
Design integration and noise studies for jet STOL aircraft. Task 7C: Augmentor wing cruise blowing valveless system. Volume 1: Static testing of augmentor noise and performance
Static performance and acoustic tests were conducted on a two-dimensional one-third-scale augmentor flap model that simulated a cruise blowing augmentor system designed for a scale augmentor flap model that simulated a cruise blowing augmentor, which offers a degree of 150-passenger STOL airplane. The cruise blowing augmentor, which offers a degree of simplicity by requiring no fan air diverter valves, was simulated by fitting existing lobe suppressor nozzles with new nozzle fairings. Flow turning performance of the cruise blowing augmentor was measured through a large range of flap deflection angles. The noise suppression characteristics of a multilayer acoustic lining installed in the augmentor were also measured
Development and application of a non-Gaussian atmospheric turbulence model for use in flight simulators
A method is described for generating time histories which model the frequency content and certain non-Gaussian probability characteristics of atmospheric turbulence including the large gusts and patchy nature of turbulence. Methods for time histories using either analog or digital computation are described. A STOL airplane was programmed into a 6-degree-of-freedom flight simulator, and turbulence time histories from several atmospheric turbulence models were introduced. The pilots' reactions are described
More than Words for Working with Children and Families
Introdiction to the special issue, "More than Words for Working with Children and Families.
On the Erasure and Regeneration of the Primordial Baryon Asymmetry by Sphalerons
We show that a cosmological baryon asymmetry generated at the GUT scale,
which would be destroyed at lower temperatures by sphalerons and possible new
B- or L-violating effects, can naturally be preserved by an asymmetry in the
number of right-handed electrons. This results in a significant softening of
previously derived baryogenesis-based constraints on the strength of exotic B-
or L-violating interactions.Comment: 10 pp. LaTex (2 figures, included) UMN-TH-1201/9
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