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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 368-372 (Feb. 2008), p. 686-687 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The sintering activation energy of high-purity alumina powders with different particle sizeswas evaluated under non-isothermal condition. It was found that, during sintering, the activation energyfor the lower temperature stage is higher than that for higher temperature stage. The value of theactivation energies for the powder compact with larger particle size was higher than that for the powdercompact with smaller particle size. If the selected temperature interval for calculation was narrowenough, the evaluated activation energy values varied with the increasing temperature continuously
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1436-5073
    Keywords: derivative spectrophotometry ; neodymium ; methyl thymol blue ; cetylpyridinium chloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A sensitive and selective method is described for the determination of neodymium in mixed rare earths using fourth-derivative spectrophotometry. The method is based on the absorption spectra of 4f electron transitions of the complex of neodymium with methyl thymol blue and cetylpyridinium chloride. The influence of various instrumental parameters and reaction conditions for maximum colour development are investigated. The calibration curve is linear over the range 0–3.5 μg ml−1 neodymium. The relative standard deviation for determination of 1.4 μg ml−1 neodymium (n = 7) is 1.6%. The detection limit (signal-to-noise ratio = 3) is 0.2 μg ml−1.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine empfindliche und selektive Methode zur Bestimmung von Nickel mit Cadion und 1,10-Phenanthrolin wurde ausgearbeitet. Sie beruht auf der Bildung eines roten ternären Komplexes in alkalischer Lösung (0.5N NaOH). Bei 505 nm entspricht die Färbung dem Beerschen Gesetz zwischen 0 und 2,5μg Ni(II)/5 ml Chloroform. Der Komplex läßt sich mit Chloroform extrahieren. Die Empfindlichkeit der Reaktion beträgt 0,000587μg· cm−2 und die molare Absorption 1.0×105l·mol−1·cm−1. Die Bestimmung von Nickel in Stahl, Aluminiumlegierungen und Böden ergab zufriedenstellende Resultate.
    Notes: Summary A sensitive and selective spectrophotometric method has been developed for the determination of nickel, based on the formation of red ternary complex of nickel with cadion and 1,10-phenanthro- line in alkaline solution (0.5N NaOH). The complex is quantitatively extracted by chloroform and exhibits an absorption maximum at 505 nm. Beer's law is obeyed in the concentration range of 0–2.5μg of Ni(II)/5 ml chloroform. The Sandell sensitivity and molar absorptivity of the reaction are 0.000587μg cm−2 and 1.0×l05l· mol−1·cm−1, respectively. The method has been applied to the determination of nickel in alloy steels, aluminium alloys and soils.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1436-5073
    Keywords: neodymium ; erbium ; 5,7-dibromo-8-hydroxyquinoline ; rare earths determination ; derivative spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The absorption spectra of 4f electron transitions of the complexes of neodymium and erbium with 5,7-dibromo-8-hydroxyquinoline in the presence of octylphenol poly(ethyleneglycol)ether have been studied by normal and third-derivative spectrophotometry. The proposed method is free of interference of other rare earths. The calibration graphs were linear up to 18 μg/ml of neodymium and 21 μg/ml of erbium (in the final solution). The derivative molar absorptivities are 395 l.mol–1.cm−1 for neodymium and 3421.mol−1.cm−1 for erbium. The corresponding values of Sandell's sensitivity were 0.36 and 0.49 μg.cm−1, respectively. The relative standard deviations evaluated from ten independent determinations of 2.5 μg/ml of neodymium and erbium are 1.5 and 3.8% for neodymium and 1.8 and 4.1% for erbium in absence and presence of 70 μg of lanthanum, respectively. The detection limits (signal to noise ratio=2) are 0.23 μg/ml for neodymium and 0.30 μg/ml for erbium. The method has been used for the determination of neodymium and erbium in mixed rare earths with satisfactory results.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 546-549 (May 2007), p. 1033-1036 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Deformation microstructures and micro-orientations of columnar grains with differentorientations in a polycrystalline high purity Al cold-rolled up to 65% (thickness reduction) wereinvestigated using electron backscatter diffraction (EBSD) technique. It was found that rotations wereInhomogeneous within the individual grains, the rotation angles of the parts close to the initialboundaries (BPs) were smaller than those remote from the boundaries (IPs), e.g. the deviation anglesbetween the BPs and the IPs were 5-6° in the grains with 〈001〉//RD orientation, leading to therotation along the α-fiber, while the deviation angles were 5-12° in the grains with 〈121〉//NDorientation rotating toward the β-fiber. These results demonstrated that the microstructures and localrotations of various parts within the rolled individual columnar grains were influenced by their initialorientations and boundaries
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Norfloxacin (NFX) is proposed as reagent for the derivative spectrophotometric determination of neodymium, holmium and erbium in mixed rare earths. The absorption spectra of 4f electron transitions of the systems of neodymium, holmium and erbium complexes with norfloxacin in presence of cetylpyridinium chloride were studied by normal and derivative spectra. The absorption bands found normally at 575 nm for neodymium, 450 nm for holmium and 523 nm for erbium were enhanced markedly. Using the second derivative spectrum, Beer’s Law is obeyed from 5.0 × 10–5∼ 2.5 × 10–4 mol dm–3 for neodymium, holmium and erbium. The relative standard deviations are 1.0, 1.4 and 1.1% for 6.9 × 10–5 mol dm–3 of neodymium, 6.1 × 10–5 mol dm–3 of holmium and 6.0 × 10–5 mol dm–3 of erbium, respectively. A method for the direct determination of neodymium, holmium and erbium in mixtures of rare earth elements with good accuracy and selectivity, is described.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 344 (1992), S. 356-357 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 2-(5-Nitro-2-pyridylazo)-5-dimethylaminobenzoic acid has been found to be a suitable precolumn derivatization reagent for the separation of Co, Ni and Pd. The detection limit for Pd at 665 nm is 0.64 ppb; the linear calibration range is 8–400 ppb.
    Type of Medium: Electronic Resource
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