Now showing items 1-10 of 17
An upper and lower solution approach for a generalized Thomas–Fermi theory of neutral atoms
An upper and lower solution theory for boundary value problems modeled from the Thomas-Fermi equation, was presented. The approach was subjected to a boundary condition corresponding to the neutral atom with Bohr radius. ...
Sign-changing and multiple solutions for the p-Laplacian
We obtain a positive solution, a negative solution, and a sign-changing solution for a class of p-Laplacian problems with jumping nonlinearities using variational and super-subsolution methods.
Oscillation criteria for a class of partial functional-differential equations of higher order
Higher order partial differential equations with functional arguments including hyperbolic equations and beam equations are studied. Sufficient conditions are derived for every solution of certain boundary value problems ...
Wide binary systems and the nature of high-velocity white dwarfs
We present measured radial velocities and complete space motions for 116 white dwarf stars with M dwarf companions. Thirteen pairs have " halo-like " velocities. According to a recent study by Oppenheimer et al., all these ...
Spectral properties of He and heavy ions in ³He-rich solar flares
Using advanced instrumentation on the ACE spacecraft, we have conducted a survey of solar energetic particle spectra in ³He-rich events over a broad energy range ∼80 keV nucleon-1 to 15 MeV nucleonˉ¹ during the period 1997 ...
A new heavy ion abundance enrichment pattern in ³He-rich solar particle events
We report the first examples of ³He-rich solar energetic particle (SEP) events with heavy ion enrichments that are not ordered generally by mass. A second new feature is the large enrichment of ¹⁴N, the first time large ...
Tip of the red giant branch distances to NGC 4214, UGC 685, and UGC 5456
We have used WFPC2 VRI observations to calculate the distances to three nearby galaxies, NGC 4214, UGC 685, and UGC 5456, using the tip of the red giant branch method. Our values for NGC 4214 (2.94 ± 0.18 Mpc) and UGC 685 ...
A determination of the local density of white dwarf stars
The most recent version of the Catalog of Spectroscopically Identified White Dwarfs lists 2249 white dwarf stars. Among these stars are 109 white dwarfs that have either reliable trigonometric parallaxes or color-based ...
Asteroseismology of RXJ 2117+3412, the hottest pulsating PG 1159 star
The pulsating PG 1159 planetary nebula central star RXJ 2117+3412 has been observed over three successive seasons of a multisite photometric campaign. The asteroseismological analysis of the data, based on the 37 identified ...
Stability analysis of nonlinear Lyapunov systems associated with an nth order system of matrix differential equations
This paper introduces the notion of Lipschitz stability for nonlinear nth order matrix Lyapunov differential systems and gives sufficient conditions for Lipschitz stability. We develop variation of parameters formula for ...