723 research outputs found
Preliminary investigations of the significance of the ingestion pathway following accidental releases with actinides
WIYN/Hydra Detection of Lithium Depletion in F Stars of the Young Open Cluster M35 and Implications for the Development of the Lithium Gap
We report discovery of significant depletion of Li on the surfaces of F dwarf
stars in the 150-Myr-old open cluster M35, analagous to a feature in the
700-Myr-old Hyades cluster that has been referred to as the ``Li gap.'' We have
caught the gap in the act of forming: using high resolution, high S/N,
WIYN/Hydra observations, we detect Li in all but a few M35 F stars; the maximum
depletion lies at least 0.6-0.8 dex below minimally depleted (or undepleted)
stars. The M35 Li depletion region, a) is quite wide, with clear depletion seen
from 6000K to 6700K or hotter; b) shows a significant dispersion in Li
abundance at all T_eff, even with stars of the same T_eff; and c) contains
undepleted stars (as well as depleted ones) in the (narrow) classical Hyades
gap region, which itself shows no undepleted stars. All of these M35 Li
depletion properties support rotationally-induced slow mixing as the primary
physical mechanism that forms the gap, and argues against other proposed
mechanisms, particularly diffusion and steady main sequence mass loss. When
viewed in the context of the M35 Li depletion properties, the Hyades Li gap may
well be wider than is usually recognized.Comment: 14 Pages, 3 figures. Accepted to ApJ Letter
Near-Field Scanning Microwave Microscopy: Measuring Local Microwave Properties and Electric Field Distributions
We describe the near-field microwave microscopy of microwave devices on a
length scale much smaller than the wavelength used for imaging. Our microscope
can be operated in two possible configurations, allowing a quantitative study
of either material properties or local electric fields.Comment: 4 pages, 8 figures, minor corrections to text and 2 figure
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