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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 274 (1975), S. 1-7 
    ISSN: 1618-2650
    Keywords: Best. von Seltenen Erden in extraterrestrischem Material ; Aktivierungsanalyse, Neutronen ; Trenn. durch GC und Elektrophorese
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Neutronenaktivierungsanalyse ist für die Bestimmung Seltener Erden in extraterrestrischen Materialien gut geeignet. Nach einer Gruppenabtrennung der Lanthanoiden kann — ohne weitere Auftrennung der Seltenen Erden — die Radioaktivität und damit der Gehalt an Seltenen Erden ermittelt werden. Allerdings sind Abklingperioden von 26 Tagen erforderlich. Sollen die Analysenergebnisse in kurzer Zeit vorliegen, müssen die Seltenen Erden aufgetrennt werden. Gas-chromatographische und elektrophoretische Verfahren werden beschrieben. Die Nachweisgrenze nach der gas-chromatographischen Trennung von Metallchelaten kann durch die Verwendung radioaktiver Reagentien hoher spezifischer Aktivität wesentlich verbessert werden. Die bisherigen Experimente können jedoch nur als Modellversuche angesehen werden. Die elektrophoretische Trennung Seltener Erden liefert die Ergebnisse in wesentlich kürzerer Zeit (innerhalb 12 h), doch ist der manuelle Arbeitsaufwand bedeutend höher. Wegen der ausgezeichneten Auftrennung der einzelnen Seltenen Erden ist es aber möglich, eine β-Zählung der radioaktiven Seltenen Erden mit Hilfe der Flüssigszintillationsmethode automatisch und mit vorzüglicher Zählausbeute durchzuführen.
    Notes: Abstract The detection limits in neutron activation analysis are up to the standards of extraterrestrical matter analysis. Instrumental analysis is possible only after a group separation of the rare earth elements. The measurements requires a 26 day decay period. If results are desired within a shorter time interval the individual rare earth elements have to be separated. Gas chromatography and electrophoresis were applied in this work. Gas chromatography of metal chelates using radioactive reagents with high specific activity significantly improves the detection limits. The gas-chromatographic separations, however, should be only regarded as model experiments. The experimental results were obtained much faster (within 12 h) by applying high voltage electrophoresis of rare earth elements. Because of the excellent separation, the rare earth elements can be determined by automatic β-liquid scintillation spectrometry with high counting yields.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 296-299 
    ISSN: 1618-2650
    Keywords: Best. von Spurenelementen, Schwermetallen in Biolog. Material ; Aktivierungsanalyse, Neutronen ; Pb-Zn-Belastung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Biologisches Material aus einem durch Blei- und Zinkbergbau mit Schwermetallen stark belasteten Gebiet wurden mittels Neutronenaktivierungsanalyse auf ihren Spurenelementgehalt untersucht. In Grünfutterproben liegen die Elemente Zn, Mo und — wie aus anderen Arbeiten hervorgeht — Pb in sehr großen Menegen vor. Fleisch- und Leberproben pflanzenfressender Tiere aus dem untersuchten Gebiet zeigten mit Ausnahme von Antimon keine Abweichungen von entsprechenden Durchschnittswerten aus nicht belasteten Gebieten. Antimon wurde in Grünfutter- und Fleischproben sowie in Rehleber in signifikant erhöhter Konzentration aufgefunden.
    Notes: Summary Biological material originating from a lead and zinc mining area contaminated with heavy metal ions was analyzed for its trace element content by neutron activation analysis. In samples of green fodder the content of Zn and Mo is very high. Liver and meat samples of herbivorous animals from the contaminated mining area showed with the exception of Sb no significant difference in the trace element composition in comparison to mean values from uncontaminated areas. The Sb content was found to be significantly higher in all samples.
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  • 3
    Publication Date: 2011-08-17
    Description: A single flare event with a rise time of about 7 s and a decay time of approximately 40 s was observed by the Goddard cosmic X-ray spectroscopy experiment on OSO-8 during observations of 3U 0614+09 in September 1975. The possibility is discussed that the source was 3U 0614+09, which has been compared with the low-mass binary Sco X-1. The spectra during the event could be fitted with blackbody (kT = 0.8-1.1 keV) or thermal bremsstrahlung (kT = 1.1-2.5 keV) models with absorption by cool material. In the blackbody model the source was of the order of 1 million cm in size.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 182
    Format: text
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  • 4
    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 61; 2, Oc; Oct. 197
    Format: text
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  • 5
    Publication Date: 2011-08-17
    Description: Data on X-ray bursts recorded by the OSO-8 and SAS-3 satellites and criteria (rise time, duration, recurrence) for X-ray bursts are examined in a study of possible correlation between the galactic longitude distribution of X-ray burst sources and globular clusters. Correlations are weak, with only two X-ray bursts sources (NGC6624 and the rapid burster) coinciding with globular clusters, another seven possibly coinciding, most not correlated. Ad hoc explanations (globular clusters obscured by dust clouds, bursts associated with remnants of disrupted globular clusters evolved into supermassive black holes) are considered briefly.
    Keywords: ASTROPHYSICS
    Type: Nature; 267; May 5
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  • 6
    Publication Date: 2011-08-17
    Description: The Solid State Spectrometer on the Einstein Observatory has detected line emission from Mg, Si and S in the thermal X-ray spectrum of the supernova remnant G292.0 + 1.8. An over-abundance of sulfur and a probable under-abundance of iron relative to their solar values is indicated by the data. The X-ray and optical data for this object support an interpretation of emission originating in ejecta from the comparatively recent explosion of a massive (about 20-solar-mass) progenitor star.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 193
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  • 7
    Publication Date: 2011-08-17
    Description: Observations of the neighboring X-ray pulsars 4U 1145-61 and 1E 1145.1-6141 obtained by OSO 8, HEAO 1 and the Einstein Observatory between 1975 and 1979 are reported. A temporal analysis of Einstein Solid State Spectrometer and Monitor Proportional Counter data, OSO 8 A and C detector data and HEAO 1 A-2(3) experiment data confirms the presence of two periodicites at 291 and 297 sec in the region, with the shorter period located within 3 arcmin of 4U 1145-61. Observations indicate the spectrum of 4U 1145-61 to obey a power law with an index of 1.5 out to at least 60 keV, with little variation with pulse phase, and a 500-eV EW iron line at 6.7 keV. The spectrum of the other source is found to be more absorbed. Similarities between the pulsars are noted, and it is suggested that they may be the result of pulsar formation in a homogeneous cloud of progenitors.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 239
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  • 8
    Publication Date: 2011-08-17
    Description: The Solid State Spectrometer on Einstein has been used to study Algol. Two observations six months apart were made, both including a primary optical eclipse. No corresponding X-ray eclipses were seen. During the second observation the source was flaring and was on the average a factor of three brighter. The spectrum on both occasions was consistent with a two-component thermal equilibrium model with temperatures of approximately 7.5 and 40 million degrees. Attempts to insert a third component indicate the temperature distribution to be bimodal. Models for the X-ray emission are discussed and it is suggested that it most likely originates from an active corona surrounding the K star.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 239
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  • 9
    Publication Date: 2011-08-17
    Description: The X-ray spectrum of Her X-1 was observed in the energy range from 2 to 24 keV from August 29 to September 3, 1975. Emission features are observed near the K-alpha iron-line energy which exhibit both broadening and a double line structure. The total luminosity in these features is about 4 by 10 to the 35th power ergs/s. Iron line fluorescence from an opaque cool (not exceeding 1 million K) shell of material at the Alfven surface provides the necessary luminosity in this feature. The double line structure and the line energy width can be due to Doppler shifts if the shell is forced to corotate with the pulsar at a radius of at least 800 million cm. Implications of this model regarding physical conditions near Her X-1 are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 215
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  • 10
    Publication Date: 2011-08-16
    Description: The paper presents observations of the distribution of intensity and linear polarization over the radio source CTB 80 at 6 and 2.8 cm. The physical nature of the source is examined, particularly the relation between the strong central component and a ridgelike structure that extends across the northern half in the E-W direction. The structure, nonthermal spectrum, and polarization of the central component are found to be very similar to those of a supernova remnant, but the ridge is shown to be unlike any feature of any other SNR. It is suggested that the ridge may have resulted from expansion of the remnant shell into a dense interstellar cloud or, alternatively, that CTB 80 might be a nearby extragalactic radio source similar to Centaurus A.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 51; 1, Au; Aug. 197
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