79,029 research outputs found
Analytical smoothing effect of solution for the boussinesq equations
In this paper, we study the analytical smoothing effect of Cauchy problem for
the incompressible Boussinesq equations. Precisely, we use the Fourier method
to prove that the Sobolev H 1-solution to the incompressible Boussinesq
equations in periodic domain is analytic for any positive time. So the
incompressible Boussinesq equation admet exactly same smoothing effect
properties of incompressible Navier-Stokes equations
Measuring and interpreting current permanent and transitory earnings and dividends : methods and applications / BEBR No. 815
Bibliography: p. 21-22
A Morphological Approach to the Pulsed Emission from Soft Gamma Repeaters
We present a geometrical methodology to interpret the periodical light curves
of Soft Gamma Repeaters based on the magnetar model and the numerical
arithmetic of the three-dimensional magnetosphere model for the young pulsars.
The hot plasma released by the star quake is trapped in the magnetosphere and
photons are emitted tangent to the local magnetic field lines. The variety of
radiation morphologies in the burst tails and the persistent stages could be
well explained by the trapped fireballs on different sites inside the closed
field lines. Furthermore, our numerical results suggests that the pulse profile
evolution of SGR 1806-20 during the 27 December 2004 giant flare is due to a
lateral drift of the emitting region in the magnetosphere.Comment: 7 figures, accepted by Ap
Safe Concurrency Introduction through Slicing
Traditional refactoring is about modifying the structure of existing code without changing its behaviour, but with the aim of making code easier to understand, modify, or reuse. In this paper, we introduce three novel refactorings for retrofitting concurrency to Erlang applications, and demonstrate how the use of program slicing makes the automation of these refactorings possible
System identification and structural control on the JPL Phase B testbed
The primary objective of NASA's CSI program at JPL is to develop and demonstrate the CSI technology required to achieve high precision structural stability on large complex optical class spacecraft. The focus mission for this work is an orbiting interferometer telescope. Toward the realization of such a mission, a series of evolutionary testbed structures are being constructed. The JPL's CSI Phase B testbed is the second structure constructed in this series which is designed to study the pathlength control problem of the optical train of a stellar interferometer telescope mounted on a large flexible structure. A detailed description of this testbed can be found. This paper describes our efforts in the first phase of active structural control experiments of Phase B testbed using the active control approach where a single piezoelectric active member is used as an actuation device and the measurements include both colocated and noncolocated sensors. Our goal for this experiment is to demonstrate the feasibility of active structural control using both colocated and noncolocated measurements by means of successive control design and loop closing. More specifically, the colocated control loop was designed and closed first to provide good damping improvement over the frequency range of interest. The noncolocated controller was then designed with respect to a partially controlled structure to further improve the performance. Based on our approach, experimental closed-loop results have demonstrated significant performance improvement with excellent stability margins
Supersymmetric Mean-Field Theory of t-J Model
The supersymmetric formulation of t-J model is studied in this paper at the
mean-field level where -T phase diagram is computed. We find that
slave-fermion-like spiral phase is stable at low doping concentration, and the
slave-boson-like d-wave fermionic spin pairing state becomes energetically
favourable when 0.23. An improvement in free energy using
Gutzwiller's method lowers the transition doping concentration to 0.06. We also
point out the existence of new branches of excitations in the supersymmetric
theory.Comment: 11 pages and 2 figure
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