49,823 research outputs found
Spatial variation of iron abundance in the high speed solar wind, 1972 to 1976
The Fe/H ratios in the peaks of high speed streams (HSS) during the decline of Solar Cycle 20 and the following minimum (October 1972-December 1976) were analyzed. The response of the 50-200 keV ion channel of the APL/JHU energetic particle experiment (EPE) on IMP-7 and 8 to solar wind iron ions at high solar wind speeds and Fe measurements were compared with solar wind H and He parameters from the Los Alamos National Laboratory (LANL) instruments on the same spacecraft. In general, the Fe distribution parameters (bulk velocity, flow direction, temperature) are found to be similar to the LANL He parameters. Although the average Fe/H ratio in many steady HSS peaks agrees within observational uncertainties with the nominal coronal ratio of 4.7 x 10(-5), abundance variations of a factor of up to 6 are obtained across a given coronal-hole associated HSS. Over the period 1973-1976, a steady decrease in the average quiet-time Fe/H ratio by a factor of about 4 is measured on both IMP-7 and 8
Solar wind iron abundance variations at solar wind speeds up to 600 km s sup -1, 1972 to 1976
The Fe/H ratios in the peaks of high speed streams (HSS) were analyzed during the decline of Solar Cycle 20 and the following minimum (October 1972 to December 1976). The response of the 50 to 200 keV ion channel of the APL/JHU energetic particle experiment (EPE) on IMP-7 and 8 was utilized to solar wind iron ions at high solar wind speeds (V or = 600 km/sec). Fe measurements with solar wind H and He parameters were compared from the Los Alamos National Laboratory (LANL) instruments on the same spacecraft. In general, the Fe distribution parameters (bulk velocity, flow direction, temperature) are found to be similar to the LANL He parameters. Although the average Fe/H ration in many steady HSS peaks agrees within observational uncertainties with the nominal coronal ratio of 4.7 x 0.00001, abundance variations of a factor of up to 6 are obtained across a given coronal-hole associated HSS
Conditions for spin squeezing in a cold 87Rb ensemble
We study the conditions for generating spin squeezing via a quantum
non-demolition measurement in an ensemble of cold 87Rb atoms. By considering
the interaction of atoms in the 5S_{1/2}(F=1) ground state with probe light
tuned near the D2 transition, we show that, for large detunings, this system is
equivalent to a spin-1/2 system when suitable Zeeman substates and quantum
operators are used to define a pseudo-spin. The degree of squeezing is derived
for the rubidium system in the presence of scattering causing decoherence and
loss. We describe how the system can decohere and lose atoms, and predict as
much as 75% spin squeezing for atomic densities typical of optical dipole
traps.Comment: 9 pages, 3 figures, submitted to J. Opt. B: Quantum Semiclass. Opt.
Proceedings of ICSSUR'0
Orbital correlations in the pseudo-cubic \emph{O} and rhombohedral -phases of LaMnO
The local and intermediate structure of stoichiometric LaMnO has been
studied in the pseudocubic and rhombohedral phases at high temperatures (300 to
1150 K). Neutron powder diffraction data were collected and a combined Rietveld
and high real space resolution atomic pair distribution function analysis
carried out. The nature of the Jahn-Teller (JT) transition around 750 K is
confirmed to be orbital order to disorder. In the high temperature orthorhombic
() and rhombohedral () phases the MnO octahedra are still fully
distorted locally. The data suggest the presence of local orbitally ordered
clusters of diameter \AA (four MnO octahedra) implying
strong nearest neighbor JT anti-ferrodistortive coupling.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Le
Acoustic characterization of crack damage evolution in sandstone deformed under conventional and true triaxial loading
We thank the Associate Editor, Michelle Cooke, and the reviewers, Ze'ev Reches and Yves Guéguen, for useful comments which helped to improve the manuscript. We thank J.G. Van Munster for providing access to the true triaxial apparatus at KSEPL and for technical support during the experimental program. We thank R. Pricci for assistance with technical drawings of the apparatus. This work was partly funded by NERC award NE/N002938/1 and by a NERC Doctoral Studentship, which we gratefully acknowledge. Supporting data are included in a supporting information file; any additional data may be obtained from J.B. (e-mail: [email protected]).Peer reviewedPublisher PD
Material studies related to lunar surface exploration. Volume 4 - Preliminary studies for the design of engineering probes Final report, 6 Mar. 1967 - 30 Jun. 1968
Preliminary design of engineering probes for studying lunar surface material propertie
Material studies related to lunar surface exploration Technical summary report, 6 Mar. 1967 - 30 Jun. 1968
Summary of research studies on lunar surface material propertie
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