ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Superconducting YBa2Cu3O7_x was prepared and characterized by the methods described in ref. 3; X-ray diffraction confirmed the presence of a single phase. The ESR measurements were made on a pellet measuring 1x2x4 mm, on an x-band spectrometer (Varian V-4502), and the temperature was varied between ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 342 (1992), S. 367-369 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An inductively coupled argon plasma-atomic emission spectrometric (ICP-AES) method has been developed for the direct determination of metallic constituents of high-critical temperature (Tc) superconducting materials with a precision of better than 2%. The typical sample matrices are YBa2Cu3O7−x, Bi2CaSr2Cu2O8 and TlBa2Ca2Cu3O8.5 and also with substitution at significant concentrations of elemental Fe, Gd, K, La, Mg, Na, Sn and Tm. The detection limits for these elements vary in the range 0.01–0.1 μg/ml. The method is based on dissolution of the solids and analysis of 1 mg/ml aliquot of the samples. Apart from optimisation of experimental parameters, the method also involves inter-element interference studies. It has been successfully applied for the chemical characterisation of a variety of oxide-based superconducting materials.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 245 (2000), S. 521-526 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract An Electron Spin Resonance (ESR) study of radiation induced free radicals in the commonly used detergent powder (Surf), was conducted to examine its potential application for retrospective/high level dosimetry, including possible dating of the accidents. The radical ions present in the irradiated detergent powder were identified as arising predominantly from sodium tri poly phosphate (Na3P5O10) and sodium sulphate (Na2SO4). The physical mixture of sodium tri poly phosphate and sodium sulphate in 4:1 ratio was found to give an ESR response, similar to that of the detergent powder. These results suggest that the detergent powder can be used as a dosimeter in the 20 Gy to 18 kGy dose range, spanning over 3 orders of magnitude. The second derivative ESR spectra of the detergent powder irradiated to different doses showed that the relative yield of the radicals is independent of irradiation dose. The decay pattern of radicals when followed as a function of post irradiation days, lead to the idea about the contrasting decay characteristics of the radicals. From the ESR signals of the irradiated detergent samples, it is shown that radiation dose can be evaluated and the radiation incident can be dated with an accuracy of ±10%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Double sulfates of thallium and lanthanides form an interesting series of compounds with first fractional crystallization leading to the formation of tetrahydrated double sulfates. The radiation induced defects including changes in the oxidation states were studied by carrying out EPR investigations of γ-irradiated Tl (I) Ln (III) (SO4)2.4H2O (Ln=Sm, Eu and Nd) compounds. The important finding of these investigations is the formation of a radiation-induced paramagnetic center Tl2+ simultaneously with that of Eu2+, revealing their intrinsic association. Similar formation of Tl2+ was not observed in other rare earth salts, implying that the stability of the half-filled electronic configuration of Eu2+ may be responsible for the stabilization of Tl2+. Their relaxation back to Eu3+ and Tl+ simultaneously at 255 K gives further confirmation of their association and suggests that the matrix intrinsically does not favor the stabilization of Eu2+ as reported in a number of other matrices. The hyperfine coupling constant for Tl2+ was calculated using the Breit-Rabi equation and was found to be 80 GHz.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 165 (1992), S. 255-261 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This paper describes the results of photoreduction of uranyl (UO2 2+) ion to U4+ in 0.2M HNO3 and ethanol using a 308 nm XeCl excimer laser. The effects of different concentrations of ethanol and the addition of sulfamic acid on the quantum yield for U4+ formation are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 175 (1993), S. 17-24 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Accidental exposure dose assessment by electron spin resonance (ESR) technique from the free radicals generated in a cotton handkerchief has been attempted in this investigation. The cotton handkerchief, a common material carried by individuals, was taken as the medium for free radical estimation. About 55 mg of the irradiated piece of cloth was loaded into a quartz tube and the dose dependence of the ESR signal at g=2.0026 was measured at room temperature, using a Bruker ESP-300 ESR spectrometer in X-band (9.74 GHz). The intensity of this signal was found to be proportional to the dose in the range of 1–1000 Gy. The stability of the free radicals with time of storage was followed. Dependence of dose rate as well as the presence of water on the yield of free radicals were also investigated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 10 (1991), S. 760-762 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 298 (1979), S. 367-372 
    ISSN: 1618-2650
    Keywords: Best. von Lanthaniden, Europium, Dysprosium, Erbium, Samarium in Uran ; Spektralphotometrie ; Atomabsorption ; Graphitofen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary Studies were conducted on the assay of Sm, Eu, Dy and Er separated from uranium using aqueous standards by electrothermal AAS with Massmann type graphite furnace. The working curves were found to be linear in the ranges Sm (1–10 μg/ml), Eu (0.05–0.6 μg/ml), Dy (0.1–0.8 μg/ml) and Er (0.1–1.0 μg/ml). The values obtained for synthetic samples agreed favourably with those obtained by emission spectrographic method. Experiments using pyrolytic carbon coated tubes with and without pretreatment by La, Ta and Y have shown an enhancement with treatment upto a maximum of 15% and improve the memory effect marginally. The effect of Ta treatment was found to be singularly useful in improving the general behaviour of Sm. The interference effects of lanthanides, other than the analyte, were found to be negligible. However, the presence of uranium was found to affect the absorbance. The absorbance of Eu was found to be nearly independent of uranium after an initial increase. On the other hand, the absorbance of other elements studied was found to drastically decrease after an initial enhancement. Detailed investigations of temperature dependence of absorbance were carried out using Eu, Dy and Er. The differences in the behaviour of these elements is attributed to probable differences in the modes of their atomization.
    Notes: Zusammenfassung Die Untersuchungen wurden mit Hilfe des Graphitrohrofens nach Maßmann durchgeführt. In folgenden Bereichen ergaben sich lineare Eichkurven: Sm 1–10 μg/ml, Eu 0,05–0,6 μg/ml, Dy 0,1–0,8 μg/ml, Er 0,1μ-1,0 μg/ml. Die aus synthetischen Proben erhaltenen Ergebnisse stimmten gut mit den durch Emissionsspektrographie erhaltenen überein. Versuche wurden mit Röhren mit pyrolytischen Kohlenstoffüberzug mit und ohne Vorbehandlung durch La, Ta und Y durchgeführt und ergaben eine bis 15%ige Steigerung durch die Behandlung sowie eine mäßige Besserung des Memoryeffektes. Eine Behandlung mit Ta war besonders für Sm vorteilhaft. Störungen durch andere Lanthanide waren vernachlässigbar. Uran beeinflußte jedoch die Absorption. Im Falle von Eu zeigte sich nach anfänglicher Zunahme fast eine Unabhängigkeit, während bei den anderen untersuchten Elementen nach anfänglicher Zunahme eine beträchtliche Abnahme auftrat. Mit Eu, Dy und Er wurde ebenfalls die Temperaturabhängigkeit der Absorption untersucht. Festgestellte Unterschiede im Verhalten werden auf unterschiedliche Atomisierung zurückgeführt.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 338 (1990), S. 255-258 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An Atomic Emission Spectrometric (AES) method has been developed for the direct determination of twenty-two metallic elements at trace concentrations in thorium oxide. The method is based on the use of a d.c. arc — carrier distillation technique with 12% composition of a mixed carrier, viz. AgCl+SrF2 in 5:1 proportion, and is equally applicable to both volatile and refractory analytes. A direct reading emission spectrometer with computerised data acquisition and processing facility has been used in these studies. The standardisation procedure includes study of volatilisation/excitation characteristics of the analyte elements to optimise choice and proportion of the carrier and signal integration time apart from optimisation of other experimental parameters such as arc current, viewing position of the arc plasma, sample charge etc. The detection limits for the analytes lie in the range 0.1–50 ppm while the precision of determinations is better than 15% for most of the elements as evaluated from the repetitive analyses of spiked samples.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 354 (1996), S. 311-315 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The atomization processes involved in the Electrothermal Atomization-Atomic Absorption Spectrometric (ETA-AAS) determination of Ag, Be, Cd, Li, Na, Sn and Zn in the presence of an uranium-plutonium matrix containing 25% Pu have been investigated. The significant fall in the absorbance signal for Ag, Cd, Na and Zn in an uranium matrix and its restoration in the presence of plutonium is probably correlated with the change in the partial pressure of oxygen released from the matrix at/below the signal appearance temperature (Tapp). In case of Li and Sn, the signal remains unaffected irrespective of the U-Pu matrix which might be due to a high Tapp for these analytes. Regarding Be, the steep suppression of the signal in the presence of the plutonium matrix compared to an uranium matrix can be ascribed to the formation of stable Pu-Be compounds (PuBe13). Based on these studies, analytical procedures have been developed for the direct determination of nanogram amounts of these analytes in an U-Pu matrix with an average precision of 9% RSD.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...