scholarly journals Rapid Hard X-Ray Variability in GRO J0422+32

1998 ◽  
Vol 188 ◽  
pp. 398-399
Author(s):  
F. van der Hooft ◽  
J. van Paradijs ◽  
M. Van Der Klis ◽  
C. Kouveliotou ◽  
D.J. Crary ◽  
...  
Keyword(s):  
Decay Time ◽  
Energy Band ◽  
X Ray ◽  
Secondary Maximum ◽  
Transient Source ◽  
History Of ◽  
Burst And Transient Source

The soft X-ray transient (SXT) GRO J0422+32 (Nova Persei 1992) was detected with the Burst And Transient Source Experiment (BATSE) on board the CGRO on 1992 August 5 (Paciesas et al. 1992) (Truncated Julian Day [TJD] 8839). The source intensity of GRO J0422+32 increased rapidly, reaching a flux of ~ 3 Crab (40-230 keV) within days after its first detection (Harmon et al. 1992). Hereafter, the X-ray intensity of the source decreased exponentially with a decay time of ~ 43 days (Vikhlinin et al. 1995). A secondary maximum of the X-ray intensity was reached at TJD 8978, 139 days after the first detection of the source. The daily averaged flux history of GRO J0422+32 in the 40-150 keV energy band is presented in Figure 1.

scholarly journals Aperiodic Flux Variability in A 0535+262

1996 ◽  
Vol 165 ◽  
pp. 313-319
Author(s):  
Mark H. Finger ◽  
Robert B. Wilson ◽  
B. Alan Harmon ◽  
William S. Paciesas
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Beat Frequency ◽  
Power Spectra ◽  
Center Frequency ◽  
X Ray ◽  
Binary Pulsar ◽  
Transient Source ◽  
Flux Variability ◽  
Burst And Transient Source

A “giant” outburst of A 0535+262, a transient X-ray binary pulsar, was observed in 1994 February and March with the Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma-Ray Observatory. During the outburst power spectra of the hard X-ray flux contained a QPO-like component with a FWHM of approximately 50% of its center frequency. Over the course of the outburst the center frequency rose smoothly from 35 mHz to 70 mHz and then fell to below 40 mHz. We compare this QPO frequency with the neutron star spin-up rate, and discuss the observed correlation in terms of the beat frequency and Keplerian frequency QPO models in conjunction with the Ghosh-Lamb accretion torque model.

scholarly journals Soft Gamma Repeaters Revisited with BATSE

1996 ◽  
Vol 165 ◽  
pp. 477-488
Author(s):  
C. Kouveliotou
Keyword(s):  
Radio Source ◽  
Gamma Ray ◽  
Short Review ◽  
X Ray ◽  
Soft Gamma Repeaters ◽  
Compact Radio Source ◽  
Transient Source ◽  
Soft Gamma Repeater ◽  
Burst And Transient Source

After the first 4 years of its operation, the Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma Ray Observatory (CGRO), detected recurrent emission from two of the three known Soft Gamma Repeater (SGR) sources, SGR 1900+14 and SGR 1806-20. The reactivation of the latter prompted a quick international campaign resulting in the identification of the X-ray counterpart of the source, which also coincides with a compact radio source. The absence of detection of new sources in the 4 years of BATSE operation and the reactivation of two of the three already known SGRs, indicates that these objects are rare. We give here a short review of the previously detected SGR emissions and present the recent results obtained with BATSE.

scholarly journals X-Ray Observations of Galaxy-Quasar Associations

1996 ◽  
Vol 168 ◽  
pp. 369-380
Author(s):  
H. Arp
Keyword(s):  
Decay Time ◽  
Energy Band ◽  
High Energy ◽  
Active Galaxies ◽  
Surprising Result ◽  
Rapid Decay ◽  
Stellar Objects ◽  
X Ray ◽  
Ongoing Process ◽  
Matter Creation

Five examples of close associations of quasars with bright, low redshift galaxies have been observed in X-ray wavelengths with ROSAT. In three cases where the galaxies are detected strongly, the nuclei of the galaxies have X-ray extensions in the direction of the adjacent quasars.In all cases the active galaxies and quasars are located at the origin of apparent lines or pairs of X-ray sources, some involving filamentary X-ray connections to fainter quasars or candidate blue stellar objects. Brighter X-ray sources in these fields are found to be in excess of average survey values. The filaments and connections have measured fluxes of 1 ≲FX≲60 × 10−13erg cm−2s−1and they tend to radiate more strongly in the harder end of the 0.1-2.4 keV energy band.The most surprising result is the evidence that X-ray sources of optically diverse character are linked together in lines and extended filaments. Because of the rapid decay time of the high energy X-ray radiation, it is implied that we are observing some ongoing process possibly related to matter creation or emergence.

Lingual Dystonia Treated with Botulinum Toxin - A Case Report

1970 ◽  
Vol 24 (2) ◽  
pp. 75-78
Author(s):  
MA Hayee ◽  
QD Mohammad ◽  
H Rahman ◽  
M Hakim ◽  
SM Kibria
Keyword(s):  
Botulinum Toxin ◽  
Botulinum Toxin A ◽  
Botulinum Toxin Type A ◽  
Botulinum Toxin Type ◽  
X Ray ◽  
Medical College ◽  
Lingual Dystonia ◽  
History Of ◽  
Chest X Ray

A 42-year-old female presented in Neurology Department of Sir Salimullah Medical College with gradually worsening difficulty in talking and eating for the last four months. Examination revealed dystonic tongue, macerated lips due to continuous drooling of saliva and aspirated lungs. She had no history of taking antiparkinsonian, neuroleptics or any other drugs causing dystonia. Chest X-ray revealed aspiration pneumonia corrected later by antibiotics. She was treated with botulinum toxin type-A. Twenty units of toxin was injected in six sites of the tongue. The dystonic tongue became normal by 24 hours. Subsequent 16 weeks follow up showed very good result and the patient now can talk and eat normally. (J Bangladesh Coll Phys Surg 2006; 24: 75-78)

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

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 Foreign Body in abdomen

2015 ◽  
Vol 14 (2) ◽  
pp. 210-212
Author(s):  
Md Zakirul Alam ◽  
Mohibul Aziz
Keyword(s):  
Abdominal Pain ◽  
Foreign Body ◽  
Medical Science ◽  
X Ray ◽  
Diagnostic Center ◽  
History Of ◽  
Upper Abdominal ◽  
Married Female

A 19 years old married female presented with severe upper abdominal pain, repeated vomiting having history of swallowing a knife 7 months ago was admitted in Mordern Clinic and Diagnostic center, Joypurhat, Bangladesh. USG abdomen & X-ray (fig-1) abdomen were done when presence of a large foreign body (knife fig-3) in abdomen was made which latter on confirmed by Endoscopy of upper GIT (fig-2). Surprisingly the patient kept it in her abdomen for 7 months without any symptoms until the symptoms got worse and compelled her to seek medical help. The knife was removed by laparotomy, gastrotomy with uneventful recovery.Bangladesh Journal of Medical Science Vol.14(2) 2015 p.210-212

The History of X-Ray Analysis

1965 ◽  
Vol 3 (7) ◽  
pp. 295-300
Author(s):  
Lawrence Bragg
Keyword(s):  
X Ray ◽  
History Of

Plastic deformations in kyanites by tectonometamorphic processes: a single-crystal X-ray diffraction study

2009 ◽  
Vol 73 (3) ◽  
pp. 359-371 ◽  
Author(s):  
G. D. Gatta ◽  
N. Rotiroti ◽  
M. Zucali
Keyword(s):  
Single Crystal ◽  
X Ray Diffraction ◽  
Plastic Deformations ◽  
X Ray ◽  
Deformational History ◽  
Significant Difference ◽  
Elliptical Section ◽  
History Of ◽  
Diffraction Patterns ◽  
Two Stages

AbstractThe crystalch emistry and crystal structure of naturalky anite crystals from the Eclogitic Micaschists Complex of the Sesia-Lanzo Zone, Western Italian Alps, have been investigated by means of optical microscopy, wavelength dispersive X-ray microanalysis, and single-crystal X-ray diffraction. The association of kyanite + garnet + phengitic-mica + chloritoid suggests that the eclogite-facies stages occurred at P ≤ 2.1 GPa and T ≤ 650ºC. Kyanite grains are large (cm-sized) porphyroblasts grown dynamically during one of the deformational events related to the subduction of the Austroalpine continentalcr ust. Under the polarizing microscope, kyanite grains show almost homogeneous cores, whereas rims are sometimes symplectitic aggregates of quartz and kyanite, confirming at least two stages of growth most likely related to the multistage deformational history of these rocks. Chemical analysis shows that Fe3+ is the major substituting cation for Al3+, ranging between 0.038 and 0.067 a.p.f.u.The single-crystal X-ray diffraction investigation of the kyanites shows severely textured patterns on the (h0l)*-plane. Such evidence is not observed in the unwarped diffraction patterns on (0kl)* and (hk0)*. The most significant difference between the structuralp arameters refined in this study, with respect to those of previously published unstrained gem-quality crystals, concerns the displacement parameters. The anisotropic displacement ellipsoids of all the atomic sites are significantly larger than those previously described, and systematically oriented with the largest elliptical section almost perpendicular to [010]. The larger ellipsoids in the kyanite crystal investigated here reflect the displacement of the centre of gravity of the electron distribution, rather than an anomalous atomic thermal motion. The magnitude and orientation of the displacement parameters and the textured/strained diffraction pattern may be the result of two combined effects: (1) that the kyanite crystals are actually composed of several blocks; (2) the crystals are affected by a pervasive residual strain, as a result of tectonometamorphic plastic deformations and re-crystallization.

SEM-based mineralogical mapping at the submicrometer-scale of modern Sardinian stromatolites

2021 ◽  
Author(s):  
Juliette Debrie ◽  
Dimitri Prêt ◽  
Karim Benzerara ◽  
Jean Paul Saint Martin
Keyword(s):  
Mineralogical Composition ◽  
Treatment Method ◽  
Heterogeneous Distribution ◽  
X Ray ◽  
Mineral Phases ◽  
Saint Martin ◽  
History Of ◽  
Phase Recognition ◽  
Mineral Mixtures ◽  
Insight Into

<p>Stromatolites, i.e. macroscopically laminated carbonate rocks formed by diverse microbial communities, are particularly emblematic geobiological materials since they are the oldest evidence of life-mineral interactions, dated up to 3.5 Gyrs ago.  They are found throughout the history of the Earth and have received strong attention because they provide precious information about microbial paleobiodiversity and paleoenvironments. However, while this information is interpreted based on our knowledge about modern analogs, the latter remains very incomplete. Here, we studied recently discovered modern stromatolites from Mari Ermi<sup>1</sup>, a coastal pond in Western Sardinia, that seasonally experience severe evaporation and broad salinity variations. For this purpose, we explored the mineralogical composition of these unique sedimentary archives and its spatial variations in order to gain better insight into how mineral phases record the conditions and processes of their formation. We investigated the heterogeneous distribution of minerals using quantitative X-ray chemical maps provided by energy dispersive x-ray spectrometry analyses coupled with scanning electron microscopy (SEM-EDXS). Hyperspectral maps were analyzed using an innovative data treatment method <sup>2</sup> allowing phase recognition within the complex mineral mixtures and solid solutions encountered. This method provided quantitative data on spatial distribution, modal content and associated calculated unit formulas for each identified mineral and phase with a hundred nanometer resolution. Based on these results, we will discuss the origin of the laminations in the stromatolites.</p><p>Reference:</p><p>1. Saint Martin, J.-P. & Saint Martin, S. Geo-Eco-Marina <strong>21</strong>, 35–53 (2015a).</p><p>2. Prêt, D. et al. American Mineralogist <strong>95</strong>, 1379–1388 (2010).</p>

Sign in / Sign up

Export Citation Format

Share Document