8,027 research outputs found
Phase reduction of stochastic limit cycle oscillators
We point out that the phase reduction of stochastic limit cycle oscillators
has been done incorrectly in the literature. We present a correct phase
reduction method for oscillators driven by weak external white Gaussian noises.
Numerical evidence demonstrates that the present phase equation properly
approximates the dynamics of the original full oscillator system.Comment: 4 pages, 2 figure
Probabilistic qualitative response estimation of the spatial market for Powder River Basin coal
Observation of Plasma Hole in an ECR Ar Plasma
The first experimental observation of a plasma hole structure in an ECR argon plasma is reported. The plasma hole is a cylindrical density cavity, which is formed spontaneously in the center of the plasma. The steep density gradient between the hole plasma and the ambient plasma is sustained by a thin interfacial layer, the width of which is a few ion Larmor radii. Supersonic rotation is found over the large cross-sectional area of Ar plasma hole. The axial flow can also exceed ion sound speed. Spectral measurements revealed that the neutral density profile exhibits a hole structure as well as that in ion density, the diameter of which is much shorter than the mean free path of neutral particles
Orbital Properties of Sr3Ru2O7 and Related Ruthenates Probed by 17O-NMR
We report a site-separated O-NMR study of the layered perovskite
ruthenate SrRuO, which exhibits nearly two-dimensional transport
properties and itinerant metamagnetism at low temperatures. The local hole
occupancies and the spin densities in the oxygen orbitals are obtained by
means of tight-binding analyses of electric field gradients and anisotropic
Knight shifts. These quantities are compared with two other layered perovskite
ruthenates: the two-dimensional paramagnet SrRuO and the
three-dimensional ferromagnet SrRuO. The hole occupancies at the oxygen
sites are very large, about one hole per ruthenium atom. This is due to the
strong covalent character of the Ru-O bonding in this compound. The magnitude
of the hole occupancy might be related to the rotation or tilt of the RuO
octahedra. The spin densities at the oxygen sites are also large, 20-40% of the
bulk susceptibilities, but in contrast to the hole occupancies, the spin
densities strongly depend on the dimensionality. This result suggests that the
density-of-states at the oxygen sites plays an essential role for the
understanding of the complex magnetism found in the layered perovskite
ruthenates.Comment: 9 pages, 5 figures, to be published in Phys. Rev.
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