High‐resolution VUV spectrometer/detector investigations of rare‐earth pulsed plasma source (abstract)

1985 ◽  
Vol 56 (5) ◽  
pp. 868-868
Author(s):  
J. R. Roberts ◽  
C. L. Cromer ◽  
J. M. Bridges ◽  
T. B. Lucatorto
Keyword(s):  
Rare Earth ◽  
High Resolution ◽  
Plasma Source ◽  
Pulsed Plasma

scholarly journals High resolution observations of spectral width features associatedwith ULF wave signatures in artificial HF radar backscatter

2004 ◽  
Vol 22 (1) ◽  
pp. 169-182 ◽  
Author(s):  
D. M. Wright ◽  
T. K. Yeoman ◽  
L. J. Baddeley ◽  
J. A. Davies ◽  
R. S. Dhillon ◽  
...  
Keyword(s):  
High Resolution ◽  
Plasma Source ◽  
Spectral Width ◽  
Hf Radar ◽  
Mhd Waves ◽  
Small Scale ◽  
Ulf Waves ◽  
Source Population ◽  
Radar Backscatter ◽  
Field Lines

Abstract. The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types. Key words. Magnetospheric physics (MHD waves and instabilities) – Space plasma physics (wave-particle interactions) – Ionosphere (active experiments)

High-resolution study of incoherent twin boundaries and of isolated wedge microtwins in rare-earth monoclinic sesquioxides (Ln2O3-B)

1982 ◽  
Vol 45 (3) ◽  
pp. 443-454 ◽  
Author(s):  
B. Yangui ◽  
C. Boulesteix ◽  
A. Bourret ◽  
G. Nihoul ◽  
G. Schiffmacher
Keyword(s):  
Rare Earth ◽  
High Resolution ◽  
Twin Boundaries ◽  
Resolution Study

The Atomic Structure Of The Zn-Mg-Rare-Earth Quasicrystals Studied By High-Resolution Electron Microscopy

1998 ◽  
Vol 553 ◽  
Author(s):  
Eiji Abe ◽  
An Pang Tsai
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
High Resolution ◽  
Atomic Structure ◽  
Structural Model ◽  
Symmetry Plane ◽  
Atomic Clusters ◽  
Icosahedral Symmetry ◽  
Structural Description ◽  
Penrose Tiling

AbstractHigh-resolution transmission electron microscopy has been applied to study the real atomic structure of the decagonal (d-) quasicrystal in the Zn-Mg-rare-earth (RE) system, which is the first d-phase based on Frank-Kasper phase. We show that the phase has a novel structure in which the atomic arrangement in the tenfold symmetry plane can simply be interpreted as the Penrose tiling decorated by individual atoms - the simplest realization of the Penrose tiling as a real atomic structure. This is supported by the fact that a similar local atomic configuration exists in the Zn7Mg4 crystal structure. This simple structural model is in sharp contras to the idea of atomic clusters, which has been successfully used to describe the structure of quasicrystals in Altransition metal alloys. The present results strongly suggest that the symmetric atomic clusters are not an essential factor for formation of quasicrystals. Instead, a new idea of quasi-unit-cell and its covering is applied for structural description. The atomic structure of the Zn-Mg-RE icosahedral phase is also implied to follow the present concept, based on the fact that its related crystalline phases with hexagonal lattices are not built of giant atomic clusters with icosahedral symmetry.

High Resolution Powder Reflectance Spectroscopy

1969 ◽  
Vol 23 (3) ◽  
pp. 235-239 ◽  
Author(s):  
R. C. Ropp
Keyword(s):  
Rare Earth ◽  
High Resolution ◽  
Rare Earths ◽  
Reflectance Spectroscopy ◽  
Polarization Data ◽  
Rare Earth Ion ◽  
Positive Identification ◽  
Measuring Techniques ◽  
Energy States ◽  
Narrow Bands

It is possible to obtain resolution of the order of 1–2 Å in the reflectance spectroscopy of powders by carefully controlling the experimental measuring techniques. One can then identify; optically, broad bands and narrow bands of the rare earths as being upper energy states and unperturbed 4 f transitions. It is even possible to show various degrees of perturbation of 4 f energy-states of a given rare-earth ion by observing Stark states which may vary from 5–90 Å in half-width. However lack of polarization data make positive identification of these Stark states impossible.

Sign in / Sign up

Export Citation Format

Share Document