36,030 research outputs found
The cylindrical antenna with non-reflecting resistive loading
Distribution of current along center-driven cylindrical antenna with variable internal impedance per unit lengt
On the rooted Tutte polynomial
The Tutte polynomial is a generalization of the chromatic polynomial of graph
colorings. Here we present an extension called the rooted Tutte polynomial,
which is defined on a graph where one or more vertices are colored with
prescribed colors. We establish a number of results pertaining to the rooted
Tutte polynomial, including a duality relation in the case that all roots
reside around a single face of a planar graph. The connection with the Potts
model is also reviewed.Comment: plain latex, 14 pages, 2 figs., to appear in Annales de l'Institut
Fourier (1999
Spectral evidence for carbonates on Mars: Hydrous carbonates
Although many of the spectral features of the Martian samples studied are not unique mineralogical indicators, much of the current spectral data is consistent with (possibly abundant) hydrous carbonates on the surface of Mars. The absorption features in the measured samples were quite weak compared with those of anhydrous carbonates. The weak features imply that significantly more hydrous carbonates can be incorporated onto the surface before becoming spectrally evident; however, exact limits have yet to be determined. The stability of these materials in the Martian environment is not known, but their formation and occurrence in low temperature terrestrial environments makes them appealing candidates for weathering products on Mars
A simple theory of dipole antennas
Simple and quantitatively accurate representation of current distribution in dipole antenna
New spectral observations of Callisto and leading/trailing hemisphere distinctions
In December 1989 and January 1990, new observations of the leading and trailing edges of Callisto were made from the NASA Infrared Telescope Facility on Mauna Kea in Hawaii. Using the Cool Grating Array Spectrometer, spectral coverage was obtained from 1.89 to 2.46 microns and from 2.8 to 4.2 microns for both the leading and trailing hemispheres. In addition, spectral coverage of the leading hemisphere was obtained from 1.30 to 2.55 microns and from 4.2 to 4.8 microns. Interpretations of the data are given
Origin of the X-ray Quasi-Periodic Oscillations and Identification of a Transient Ultraluminous X-Ray Source in M82
The starburst galaxy M82 contains two ultraluminous X-ray sources (ULXs),
CXOM82 J095550.2+694047 (=X41.4+60) and CXOM82 J095551.1+694045 (=X42.3+59),
which are unresolved by XMM-Newton. We revisited the two XMM-Newton
observations of M82 and analyzed the surface brightness profiles using the
known Chandra source positions. We show that the quasi-periodic oscillations
(QPOs) detected with XMM-Newton originate from X41.4+60, the brightest X-ray
source in M82. Correcting for the contributions of the unresolved sources, the
QPO at a frequency of 55.8+/-1.3 mHz on 2001 May 06 had a fractional rms
amplitude of 32%, and the QPO at 112.9+/-1.3 mHz on 2004 April 21 had an
amplitude of 21%. The QPO frequency may possibly be correlated with the source
flux, similar to the type C QPOs in XTE 1550-564 and GRS 1915+105, but at
luminosities two orders of magnitude higher. X42.3+59, the second brightest
source in M82, displayed a strikingly high flux of 1.4E-11 ergs/cm^2/s in the
2-10 keV band on 2001 May 6. A seven-year light curve of X42.3+59 shows extreme
variability over a factor of 1000; the source is not detected in several
Chandra observations. This transient behavior suggests accretion from an
unstable disk. If the companion star is massive, as might be expected in the
young stellar environment, then the compact object would likely be an IMBH.Comment: 9 pages, 6 figures, submitted to ApJ on May 08, 200
The Effects of Early Harvest and Artificial Drying on Mold Deterioration and Quality of Canning Pea Seed
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