scholarly journals Neutral Clouds Within the Local X-ray Plasma

1997 ◽  
Vol 166 ◽  
pp. 165-168
Author(s):  
Jürgen Kerp ◽  
Jochen Pietz
Keyword(s):  
Optical Absorption ◽  
Energy Band ◽  
Atomic Hydrogen ◽  
Low Velocity ◽  
X Ray ◽  
Neutral Clouds ◽  
X Ray Absorption ◽  
Local Cloud ◽  
Absorption Features ◽  
Distance Limit

AbstractWe present new results based on the analysis of ROSAT PSPC observations towards nearby neutral clouds. These clouds are detectable as deep soft X-ray absorption features within the ¼ keV energy band. Towards one of these clouds, optical absorption line measurements determine an upper distance limit of D ≤ 60 pc. The presented data suggest that this filament is only a part of a much more extended local–cloud structure. Here we demonstrate that we most probably detected a local neutral atomic hydrogen “wall” in the direction of a low–velocity arc (Pietz 1994).

Energy Band Gap Studies of CdS Nanomaterials

2008 ◽  
Vol 3 ◽  
pp. 97-102 ◽  
Author(s):  
Dinu Patidar ◽  
K.S. Rathore ◽  
N.S. Saxena ◽  
Kananbala Sharma ◽  
T.P. Sharma
Keyword(s):  
Optical Absorption ◽  
Band Gap ◽  
Energy Band ◽  
Chemical Method ◽  
Optical Absorption Spectroscopy ◽  
Cds Nanoparticles ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
X Ray ◽  
Simple Chemical

The CdS nanoparticles of different sizes are synthesized by a simple chemical method. Here, CdS nanoparticles are grown through the reaction of solution of different concentration of CdCl2 with H2S. X-ray diffraction pattern confirms nano nature of CdS and has been used to determine the size of particle. Optical absorption spectroscopy is used to measure the energy band gap of these nanomaterials by using Tauc relation. Energy band gap ranging between 3.12 eV to 2.47 eV have been obtained for the samples containing the nanoparticles in the range of 2.3 to 6.0 nm size. A correlation between the band gap and size of the nanoparticles is also established.

scholarly journals Discovery of narrow X-ray absorption features from the dipping low-mass X-ray binary X 1624-490 with XMM-Newton

2002 ◽  
Vol 386 (3) ◽  
pp. 910-915 ◽  
Author(s):  
A. N. Parmar ◽  
T. Oosterbroek ◽  
L. Boirin ◽  
D. Lumb
Keyword(s):  
X Ray ◽  
Low Mass ◽  
X Ray Absorption ◽  
Absorption Features

scholarly journals Discovery of complex narrow X–ray absorption features from the low-mass X–ray binary GX 13+1 with XMM-Newton

2002 ◽  
Vol 385 (3) ◽  
pp. 940-946 ◽  
Author(s):  
L. Sidoli ◽  
A. N. Parmar ◽  
T. Oosterbroek ◽  
D. Lumb
Keyword(s):  
X Ray ◽  
Low Mass ◽  
X Ray Absorption ◽  
Absorption Features

scholarly journals Synthesis and characterisation of HIP Ca0.80Ce0.20ZrTi1.60Cr0.40O7 zirconolite and observations of the ceramic–canister interface

MRS Advances ◽  
2021 ◽  
Author(s):  
Lewis R. Blackburn ◽  
Max R. Cole ◽  
Laura J. Gardner ◽  
Daniel J. Bailey ◽  
Merve Kuman ◽  
...  
Keyword(s):  
Oxidation State ◽  
Hot Isostatic Pressing ◽  
Nominal Composition ◽  
Phase Assemblage ◽  
X Ray ◽  
Bulk Ceramic ◽  
Average Oxidation State ◽  
Temperature And Pressure ◽  
X Ray Absorption ◽  
Absorption Features

Abstract A sample of zirconolite with nominal composition Ca0.80Ce0.20ZrTi1.60Cr0.40O7 was processed via Hot Isostatic Pressing (HIP), with a dwell temperature and pressure of 1320 °C/100 MPa maintained for 4 h. The produced wasteform was characterised by powder XRD, SEM–EDS, Ce L3 and Cr K-edge XANES. A significant portion of the Ce inventory did not fully partition within the zirconolite phase, instead remaining as CeO2 within the microstructure. Inspection of the stainless steel–ceramic interface detailed the presence of an interaction region dominated by a Cr-rich oxide layer. No significant Cr or Fe migration was observed, although a greater concentration of perovskite was observed at the periphery, relative to the bulk ceramic matrix. The X-ray absorption features of Cr remained analogous with Cr3+ accommodation within TiO6 octahedra in the zirconolite matrix. The absorption edge of Ce was comprised of contributions from zirconolite-2M and unincorporated CeO2, with an average oxidation state of Ce3.9+. As zirconolite-2M accounted for > 92 wt% of the overall phase assemblage, it is clear that the dominant oxidation state of Ce in this phase was Ce4+. Graphic abstract

X-Ray Absorption Spectroscopy and Optical Absorption Studies of the Growth of CdS Nanocrystals in Glass

1994 ◽  
Vol 358 ◽  
Author(s):  
P. D. Persans ◽  
L. B. Lurio ◽  
J. Pant ◽  
R. J. Olsson ◽  
H. Yukselici ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Optical Absorption ◽  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Cds Nanoparticles ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Optical Absorption Peak ◽  
Absorption Studies ◽  
X Ray Absorption

ABSTRACTWe have measured and analyzed optical absorption, Raman scattering and x-ray absorption spectra of CdS nanocrystals grown by solid-state reaction in a borosilicate glass. We observe the appearance and growth of an optical absorption peak which is attributed to CdS nanoparticles. Using x-ray absorption we quantify the progressive replacement of O nearest neighbors of Cd by S with heat treatment and the appearance and growth of a well-defined second nearest neighbor peak.

scholarly journals Electron-Ion Recombination Measurements Motivated by AGN X-Ray Absorption Features: Fe xiv Forming Fe xiii

2006 ◽  
Vol 641 (2) ◽  
pp. L157-L160 ◽  
Author(s):  
E. W. Schmidt ◽  
S. Schippers ◽  
A. Müller ◽  
M. Lestinsky ◽  
F. Sprenger ◽  
...  
Keyword(s):  
X Ray ◽  
Ion Recombination ◽  
X Ray Absorption ◽  
Absorption Features

scholarly journals Discovery of X-ray absorption features from the dipping low-mass X-ray binary XB 1916-053 with XMM-Newton

2004 ◽  
Vol 418 (3) ◽  
pp. 1061-1072 ◽  
Author(s):  
L. Boirin ◽  
A. N. Parmar ◽  
D. Barret ◽  
S. Paltani ◽  
J. E. Grindlay
Keyword(s):  
X Ray ◽  
Low Mass ◽  
X Ray Absorption ◽  
Absorption Features

scholarly journals The ionic composition of the local absorber towards 3C 273

2020 ◽  
Vol 492 (4) ◽  
pp. 5634-5640
Author(s):  
Itay Gissis ◽  
Uria Peretz ◽  
Ehud Behar
Keyword(s):  
Column Density ◽  
Ionic Composition ◽  
Elemental Abundance ◽  
Ionized Gas ◽  
X Ray ◽  
Line Region ◽  
Collisional Ionization ◽  
X Ray Absorption ◽  
Absorption Features ◽  
Measure Distribution

ABSTRACT Hot ionized gas is observed in the local vicinity of our galaxy through spectral absorption features. The most common hypothesis is that this gas forms a halo surrounding our Milky Way, in collisional ionization equilibrium. In this paper, we investigate the elemental abundance of this hot and ionized local gas. We use a 2.4 Ms stacked X-ray spectrum of the bright blazar 3C 273 and probe the local absorption features. Using ion-by-ion fitting of the X-ray absorption lines, we derive the column density of each ionization species. Based on the column densities, we reconstruct the absorption measure distribution, namely the hydrogenic column density as a function of temperature. We report the elemental abundances of C, N, Ne, and Fe relative to solar O. Previous measurements of local X-ray emission lines in conjunction with the present column densities indicate a scale height of 1–80 kpc and hydrogen number density of 10−4–10−3 cm−3 for the hot ionized gas. Additionally, we detect He-like O lines from the quasar broad line region with velocities of 6400 ± 1500 km s−1.

scholarly journals Intermolecular bonding of hemin in solution and in solid state probed by N K-edge X-ray spectroscopies

2015 ◽  
Vol 17 (43) ◽  
pp. 29000-29006 ◽  
Author(s):  
Ronny Golnak ◽  
Jie Xiao ◽  
Kaan Atak ◽  
Joanna S. Stevens ◽  
Adrian Gainar ◽  
...  
Keyword(s):  
Solid State ◽  
X Ray ◽  
Bonding Interaction ◽  
Intermolecular Bonding ◽  
X Ray Absorption ◽  
Absorption Features

Characteristic X-ray absorption features indicate the extent of hemin intermolecular bonding interaction.

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