61,891 research outputs found
Ba & Eu Abundances in M15 giant stars
To investigate the Ba and Eu abundances for a sample of 63 giant stars in the
globular cluster M15. This is the largest sample of M15 giants stars for which
Ba abundances have been determined and, due to the target selection of the
original research programme, the Ba abundances are complete along the red giant
branch. Stellar parameters were taken from the previous key study and a
microturbulence-surface gravity relation was determined for precise measurement
of the Ba line at 6496.898 Angstroms, which has a high sensitivity to
microturbulence. Element abundances for Ba, La, Eu, Ca, Ni and Fe were
calculated using spectrum synthesis and equivalent widths techniques. A bimodal
distribution in Ba, Eu and La abundances was found within the sample. The low
Ba,Eu,La mode had mean abundances of =-2.41+/-0.16,
=-1.80+/-0.08 and =-2.19+/-0.13 while the high Ba,Eu,La mode
had mean abundances of =-2.00+/-0.16, =-1.65+/-0.13 and
=-1.95+/-0.11. Both modes are indicative of a pollution scenario
dominated by the r-process, hence contributions from explosive nucleosynthesis
of massive stars. There may be evidence of further enhancement by another heavy
element process and of potential anticorrelations in Na-O for both modes
indicating a complex formation and evolution history for M15.Comment: 20 pages, 15 figure
Development of optical coatings for cos thin film solar cells third quarterly report, jun. 1 - aug. 1, 1965
Sputtering of glass coatings on cadmium sulfide thin film solar cell
Development of optical coatings for cds thin film solar cells second quarterly report, 1 mar. - 1 jun. 1965
Optical coatings for cadmium sulfide thin film solar cell
Holomorphic Extension from Weakly Pseudoconcave CR Manifolds
Let M be a smooth locally embeddable CR manifold, having some CR dimension m
and some CR codimension d. We find an improved local geometric condition on M
which guarantees, at a point p on M, that germs of CR distributions are smooth
functions, and have extensions to germs of holomorphic functions on a full
ambient neighborhood of p. Our condition is a form of weak pseudoconcavity,
closely related to essential pseudoconcavity as introduced in [HN1].
Applications are made to CR meromorphic functions and mappings. Explicit
examples are given which satisfy our new condition,but which are not
pseudoconcave in the strong sense. These results demonstrate that for
codimension d > 1, there are additional phenomena which are invisible when d =
1
Z -> b\bar{b} Versus Dynamical Electroweak Symmetry Breaking involving the Top Quark
In models of dynamical electroweak symmetry breaking which sensitively
involve the third generation, such as top quark condensation, the effects of
the new dynamics can show up experimentally in Z->b\bar{b}. We compare the
sensitivity of Z->b\bar{b} and top quark production at the Tevatron to models
of the new physics. Z->b\bar{b} is a relatively more sensitive probe to new
strongly coupled U(1) gauge bosons, while it is generally less sensitive a
probe to new physics involving color octet gauge bosons as is top quark
production itself. Nonetheless, to accomodate a significant excess in
Z->b\bar{b} requires choosing model parameters that may be ruled out within run
I(b) at the Tevatron.Comment: LaTex file, 19 pages + 2 Figs., Fermilab-Pub-94/231-
Origin of the fast magnetization tunneling in the single-molecule magnet [Ni(hmp)(tBuEtOH)Cl]4
We present high-frequency angle-dependent EPR data for crystals of
[NixZn1-x(hmp)(t-BuEtOH)Cl]4 (x = 1 and 0.02). The x = 1 complex behaves as a
single-molecule magnet at low temperatures, displaying hysteresis and
exceptionally fast magnetization tunneling. We show that this behavior is
related to a 4th-order transverse crystal-field interaction, which produces a
significant tunnel-splitting (~10 MHz) of the ground state of this S = 4
system. The magnitude of the 4th-order anisotropy, and the dominant axial term
(D), can be related to the single-ion interactions (Di and Ei) at the
individual NiII sites, as determined for the x = 0.02 crystals.Comment: 11 pages including 2 figure
Pressure Contact Sounding Data for NASA's Atmospheric Variability Experiment (AVE 3)
The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 41 stations participating in the AVE III measurement program that began at 0000 GMT on February 6 and ended at 1200 GMT on February 7, 1975. Soundings were taken at 3-hour intervals during a large period of the experiment from most stations within the United States east of about 105 degrees west longitude. Methods of data processing, change in reduction scheme since the AVE II pilot experiment, and data accuracy are briefly discussed. An example of contact data is presented, and microfiche cards of all the contact data are included in the appendix. The AVE III project was conducted to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales of-motion interrelationships
Research and development in CdS photovoltaic cells Third quarterly report, 29 Dec. 1965 - 29 Mar. 1966
Barrier formation studies of copper sulfide and cadmium sulfide in photovoltaic cell
Temperature Dependent Neutron Scattering Sections for Polyethylene
This note presents neutron scattering cross sections for polyethylene at 296
K, 77 K and 4 K derived from a new scattering kernel for neutron scattering off
of hydrogen in polyethylene. The kernel was developed in ENDF-6 format as a set
of S(alpha,beta) tables using the LEAPR module of the NJOY94 code package. The
polyethylene density of states (from 0 to sub eV) adopted to derive the new
kernel is presented. We compare our calculated room temperature total
scattering cross sections and double differential cross sections at 232 meV at
various angles with the available experimental data (at room temperature), and
then extrapolate the calculations to lower temperatures (77K and 4K). The new
temperature dependent scattering kernel gives a good quantitative fit to the
available room temperature data and has a temperature dependence that is
qualitatively consistent with thermodynamics.Comment: 6 page
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