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  • 1990-1994  (6)
  • 1965-1969  (1)
  • Chemistry  (6)
  • 65F  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Acta applicandae mathematicae 21 (1990), S. 291-313 
    ISSN: 1572-9036
    Schlagwort(e): 65F ; 65G ; Complex symmetric matrix ; equivalent symmetric matrices ; error-free matrix symmetrizers ; floating-point modular arithmetic ; Hessenberg matrices ; nonsymmetric eigenvalue problem ; parallel implementation ; QR transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract A symmetrizer of the matrix A is a symmetric solution X that satisfies the matrix equation XA=A′X. An exact matrix symmetrizer is computed by obtaining a general algorithm and superimposing a modified multiple modulus residue arithmetic on this algorithm. A procedure based on computing a symmetrizer to obtain a symmetric matrix, called here an equivalent symmetric matrix, whose eigenvalues are the same as those of a given real nonsymmetric matrix is presented.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 2943-2950 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Defatted jute stick was treated with sodium hydroxide solution (2% w/v) at ambient temperature (∼ 32∼C) and boiling water bath temperature (95-97°C). Infrared (IR) spectra of defatted jute stick and alkali-treated jute stick were studied. The IR spectra of the alkalitreated jute stick were conspicuous by the absence of the 1730 cm-1 band, as compared to that of jute stick. Another characteristic feature of the alkali treated jute sticks is the absence of the band at 1240 cm-1, which is replaced by the 1265 and 1225 cm-1 bands; other bands in the above samples also recorded significant changes.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 1607-1613 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Jute stick was treated with white-rot fungus for incubation periods of 6 days (MBA) and 12 days (MBB). The infrared spectra of fungus treated samples (MBA and MBB) and control jute stick (MBC) were analyzed and compared. The bands attributed mainly to hemicellulose show an increase in absorbance intensity ratios (Aν/A2900) with increase of incubation time. Similarly the bands attributed to lignin show an increase in the absorbance intensity ratios with increase of incubation time. Increase in the intensity of 1635 cm-1 band with increase of incubation time was also observed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 2187-2192 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Jute stick was bleached with sodium chlorite and alkaline hydrogen peroxide solutions. The infrared (IR) spectra of bleached samples and jute stick were analyzed and compared. The bleached samples were characterized by higher absorbance intensity ratios (Av/A2900) of the bands attributed to hemicellulose. Among the bleached samples the chlorite-bleached sample showed higher intensity for the bands mentioned. The bands attributed to lignin are either absent or very weak in the chlorite-bleached jute stick as compared to that of peroxide-bleached jute stick, although some residual lignin was present in the substrate. The 1635 cm-1 band attribute to the vibration of adsorbed water molecules in the noncrystalline regions in cellulose appears as a sharp peak in chlorite-bleached jute stick and as a shoulder in peroxide-bleached jute stick. This can be attributed to the difference in the nature of the two bleaching processes.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 329-336 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The infrared spectra of alkaline jute stick have been discussed and compared to that of untreated and control sample. A higher shift in the O—H and lower shift in the C—H stretching frequencies were observed in alkaline sample. The presence of a strong band at 1440-1430 cm-1 may be due to the coupling of COO- frequency with CH2 deformation frequency. The C—O stretching mode at 1240 cm-1 disappears on alkaline treatment with the formation of new peaks at 1265 and 1225 cm-1. The β-glucosidic band at 895 cm-1 is shifted to 880 cm-1 with doubled intensity in alkaline jute stick.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 25-30 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Raw and partially delignified jute fibers were grafted with acrylonitrile and methyl meth-acrylate monomers, using the redox system of initiation with ceric ammonium sulfate. Grafting was also carried out in a mixed monomer system with acrylonitrile and methyl methacrylate monomers in different proportions. The optimum grafting condition depends on the duration of grafting treatment and proportion of grafting monomers. The monomers entered the fiber matrix with high add-on and, at still higher graft add-ons, the ultimate fibers suffered disintegration. The surfaces were increasingly covered with grafted materials and longitudinal cracks developed on the fiber surface with higher add-on. © 1993 John Wiley & Sons, Inc.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 340 (1965), S. 82-85 
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Durch Umsetzung von Aquopenta-cyanorhenaten(II) mit Alkalicyaniden wurden die hexacyanoferrat(II)-analogen Salze K4[ReII(CN)6] · 3 H2O und Na4[ReII(CN)6] · 5 H2O gewonnen, die diamagnetisch und aus deren wäßrigen Lösungen die entsprechenden schwerlöslichen Cu(II)- und Co(II)-Salze auszufällen sind.
    Notizen: Preparation of K4ReII(CN)6 · 3 H2O and Na4ReII(CN)6 · 5 H2O analogous to hexacyanoferrates(II) are described. They have been prepared by the treatment of corresponding aquopentacyano-rhenates(II) with alkali cyanides. The insoluble copper and cobalt salts have also been prepared. The hexacyanorhenates(II) are diamagnetic at room temperature.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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