306,775 research outputs found
Dynamics and control of the satellite power system
An investigation of the dynamics and control problems specifically related to the Satellite Power System (SPS), to assess performance of selected control concepts, and to identify and initiate development of advanced control technology that would enhance feasibility and performance of the SPS system was made. The initial stages of the study are reported
Kerr Geodesics Following the Axis of Symmetry
We present here the general expressions for the acceleration of massive test
particles along the symmetry axis of the Kerr metric, and then study the main
properties of this acceleration in different regions of the spacetime. In
particular, we show that there exists a region near the black hole in which the
gravitational field is repulsive. We provide possible physical interpretations
about the role of this effect in terms of the different conserved parameters.
The studies of these geodesics are important not only to understand better the
structure of the Kerr spacetime but also to its use as a possible mechanism for
the production of extragalactic jets. Our results are obtained with the help of
expressing the geodesics of the Kerr spacetime in terms of the Weyl
coordinates.Comment: revtex4, no figures and tables. Gen. Relativ. Grav. 48 (2016) 6
Energy Dependence of Jet Quenching and Life-time of the Dense Matter in High-energy Heavy-ion Collisions
Suppression of high hadron spectra in high-energy heavy-ion collisions
at different energies is studied within a pQCD parton model incorporating
medium induced parton energy loss. The dependence of the nuclear
modification factor is found to depend on both the energy
dependence of the parton energy loss and the power-law behavior of the initial
jet spectra. The high hadron suppression at GeV and its
centrality dependence are studied in detail. The overall values of the
modification factor are found to provide strong constraints on the lifetime of
the dense matter.Comment: 6 pages in RevTex with 3 postscript figure
Corrections to scaling in the dynamic approach to the phase transition with quenched disorder
With dynamic Monte Carlo simulations, we investigate the continuous phase
transition in the three-dimensional three-state random-bond Potts model. We
propose a useful technique to deal with the strong corrections to the dynamic
scaling form. The critical point, static exponents and , and
dynamic exponent are accurately determined. Particularly, the results
support that the exponent satisfies the lower bound .Comment: 10 pages, 6 figures, 2 table
Tunable near- to mid-infrared pump terahertz probe spectroscopy in reflection geometry
Strong-field mid-infrared pump--terahertz (THz) probe spectroscopy has been
proven as a powerful tool for light control of different orders in strongly
correlated materials. We report the construction of an ultrafast broadband
infrared pump--THz probe system in reflection geometry. A two-output optical
parametric amplifier is used for generating mid-infrared pulses with GaSe as
the nonlinear crystal. The setup is capable of pumping bulk materials at
wavelengths ranging from 1.2 m to 15 m and beyond, and detecting the
subtle, transient photoinduced changes in the reflected electric field of the
THz probe at different temperatures. As a demonstration, we present 15 m
pump--THz probe measurements of a bulk EuSbTe single crystal. A
transient change in the reflected THz electric field can be clearly resolved.
The widely tuned pumping energy could be used in mode-selective excitation
experiments and applied to many strongly correlated electron systems.Comment: 4 pages, 4 figure
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