3,518 research outputs found
Flame-resistant thin panels of glass fabric-polyimide resin laminates
With a cured polyimide resin content of less than about 20 percent by weight of the finished part, glass fabric laminates which have good structural properties and are self-extinguishing in a pure oxygen atmosphere can be prepared in the thickness range of 0.035 to 0.08 inch
Japan's Monetary Policy Transition, 1955-2004
This paper surveys the postwar evolution of Bank of Japan (BOJ) monetary policy. Using both qualitative and quantitative data, we describe the changes in the money supply process in response to changing institutional constraints. We focus on the transition from quantitative to qualitative control mechanisms, illuminating, in particular, the important role of the BOJ=s lending guidance (Awindow guidance@) in the early periods and financial liberalization in subsequent periods. Monetary policy reaction functions are estimated and used to identify major changes in policy instruments, targets, and indicators. We analyze the historical behavior of the money multipliers and their components, highlighting reasons for their current depressed state. We conclude with comments on current challenges facing the monetary authorities.Monetary policy, Bank of Japan
Improved analysis of black hole formation in high-energy particle collisions
We investigate formation of an apparent horizon (AH) in high-energy particle
collisions in four- and higher-dimensional general relativity, motivated by
TeV-scale gravity scenarios. The goal is to estimate the prefactor in the
geometric cross section formula for the black hole production. We numerically
construct AHs on the future light cone of the collision plane. Since this slice
lies to the future of the slice used previously by Eardley and Giddings
(gr-qc/0201034) and by one of us and Nambu (gr-qc/0209003), we are able to
improve the prefactor estimates. The black hole production cross section
increases by 40-70% in the higher-dimensional cases, indicating larger black
hole production rates in future-planned accelerators than previously estimated.
We also determine the mass and the angular momentum of the final black hole
state, as allowed by the area theorem.Comment: 28 pages, 14 figures, references and minor comments adde
Periodicity and criticality in the Olami-Feder-Christensen model of earthquakes
Characteristic versus critical features of earthquakes are studied on the
basis of the Olami-Feder-Christensen model. It is found that the local
recurrence-time distribution exhibits a sharp -function-like peak
corresponding to rhythmic recurrence of events with a fixed ``period'' uniquely
determined by the transmission parameter of the model, together with a
power-law-like tail corresponding to scale-free recurrence of events. The model
exhibits phenomena closely resembling the asperity known in seismology
Jet-fluid string formation and decay in high-energy heavy-ion collisions
We propose a new hadronization mechanism, jet-fluid string (JFS) formation
and decay, to understand observables in intermediate to high- regions
comprehensively. In the JFS model, hard partons produced in jet lose their
energy in traversing the QGP fluid, which is described by fully
three-dimensional hydrodynamic simulations. When a jet parton escapes from the
QGP fluid, it picks up a partner parton from a fluid and forms a color singlet
string, then it decays to hadrons. We find that high- values in JFS
are about two times larger than in the independent fragmentation model.Comment: 6 pages, 2 figures; Proceeding for poster sessions at Quark Matter
2006, Shanghai, China, 14-20 November 2006; to appear in Int. J. of Mod.
Phys.
Electromagnetic radiation due to naked singularity formation in self-similar gravitational collapse
Dynamical evolution of test fields in background geometry with a naked
singularity is an important problem relevant to the Cauchy horizon instability
and the observational signatures different from black hole formation. In this
paper we study electromagnetic perturbations generated by a given current
distribution in collapsing matter under a spherically symmetric self-similar
background. Using the Green's function method, we construct the formula to
evaluate the outgoing energy flux observed at the future null infinity. The
contributions from "quasi-normal" modes of the self-similar system as well as
"high-frequency" waves are clarified. We find a characteristic power-law time
evolution of the outgoing energy flux which appears just before naked
singularity formation, and give the criteria as to whether or not the outgoing
energy flux diverges at the future Cauchy horizon.Comment: 20 pages, 7 figures, references added to match the published versio
Vortex jamming in superconductors and granular rheology
We demonstrate that a highly frustrated anisotropic Josephson junction
array(JJA) on a square lattice exhibits a zero-temperature jamming transition,
which shares much in common with those in granular systems. Anisotropy of the
Josephson couplings along the horizontal and vertical directions plays roles
similar to normal load or density in granular systems. We studied numerically
static and dynamic response of the system against shear, i. e. injection of
external electric current at zero temperature. Current-voltage curves at
various strength of the anisotropy exhibit universal scaling features around
the jamming point much as do the flow curves in granular rheology, shear-stress
vs shear-rate. It turns out that at zero temperature the jamming transition
occurs right at the isotropic coupling and anisotropic JJA behaves as an exotic
fragile vortex matter : it behaves as superconductor (vortex glass) into one
direction while normal conductor (vortex liquid) into the other direction even
at zero temperature. Furthermore we find a variant of the theoretical model for
the anisotropic JJA quantitatively reproduces universal master flow-curves of
the granular systems. Our results suggest an unexpected common paradigm
stretching over seemingly unrelated fields - the rheology of soft materials and
superconductivity.Comment: 10 pages, 5 figures. To appear in New Journal of Physic
Black ring formation in particle systems
It is known that the formation of apparent horizons with non-spherical
topology is possible in higher-dimensional spacetimes. One of these is the
black ring horizon with topology where is the spacetime
dimension number. In this paper, we investigate the black ring horizon
formation in systems with -particles. We analyze two kinds of system: the
high-energy -particle system and the momentarily-static -black-hole
initial data. In the high-energy particle system, we prove that the black ring
horizon does not exist at the instant of collision for any . But there
remains a possibility that the black ring forms after the collision and this
result is not sufficient. Because calculating the metric of this system after
the collision is difficult, we consider the momentarily-static -black-hole
initial data that can be regarded as a simplified -particle model and
numerically solve the black ring horizon that surrounds all the particles. Our
results show that there is the minimum particle number that is necessary for
the black ring formation and this number depends on . Although many particle
number is required in five-dimensions, is sufficient for the black ring
formation in the cases. The black ring formation becomes easier for
larger . We provide a plausible physical interpretation of our results and
discuss the validity of Ida and Nakao's conjecture for the horizon formation in
higher-dimensions. Finally we briefly discuss the probable methods of producing
the black rings in accelerators.Comment: 26 pages, 7 figure
On topological charged braneworld black holes
We study a class of topological black hole solutions in RSII braneworld
scenario in the presence of a localized Maxwell field on the brane. Such a
black hole can carry two types of charge, one arising from the extra dimension,
the tidal charge, and the other one from a localized gauge field confined to
the brane. We find that the localized charge on the brane modifies the bulk
geometry and in particular the bulk Weyl tensor. The bulk geometry does not
depend on different topologies of the horizons. We present the temperature and
entropy expressions associated with the event horizon of the braneworld black
hole and by using the first law of black hole thermodynamics we calculate the
mass of the black hole.Comment: 9 pages, references added, to appear in MPL
Nonaxisymmetric instability of rapidly rotating black hole in five dimensions
We present results from numerical solution of Einstein's equation in five
dimensions describing evolution of rapidly rotating black holes. We show, for
the first time, that the rapidly rotating black holes in higher dimensions are
unstable against nonaxisymmetric deformation; for the five-dimensional case,
the critical value of spin parameter for onset of the instability is .Comment: 4 pages, 3 figures, accepted for publication in PRD(R
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