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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3331-3333 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: GdTbCo films were rf diode sputtered from a composite target varying the argon pressure PAr and the substrate bias voltage Vb. Both the uniaxial magnetic anisotropy constant Ku and the aging behavior of the films depend strongly on the preparation parameters. The absolute maximum of Ku was obtained at Vb=−150 V. However, at this bias voltage nearly the highest oxidation rate of unprotected 100-nm-thick films was observed. Films of highest stability are obtained without any bias voltage. The oxidation rate is correlated with the Ar concentration in the films. It was argued recently that the anisotropy of sputtered films could depend on argon incorporation. Our results seem to rule out this mechanism since GdTbCo films prepared at zero bias show a relative Ku maximum in dependence on PAr where the argon concentration is near its absolute minimum. The magneto-optic Kerr rotation θK of the films can only be correlated with the Co concentration for zero bias films. Some additional variation depending on the bias voltage has been observed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 859-863 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Amorphous rare-earth transition metal alloys of composition (Gd1−xFex)1−yAuy with x=0.74, 0.77, and 0≤y≤0.40 were prepared by evaporation onto rotating glass substrates. The magnetic and magneto-optic properties have been investigated in the temperature range 4.2≤T≤TC revealing a decrease of the compensation and Curie temperature, the uniaxial anisotropy, and the Faraday and Kerr rotation with increasing gold content. The temperature behavior can be interpreted in terms of a mean-field analysis indicating a pronounced influence of the gold on the iron moment and the exchange constants. The temperature dependence of the Faraday rotation can be described in terms of the sublattice magnetizations inferred from the fit of the mean-field theory to the measured saturation magnetization.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1437-3262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Abstract Manganese nodules from the Kane Gap (a deep sea channel connecting the Sierra Leone and Gambia Basins off West Africa) were investigated chemically and dated by10Be along cross-sections. Comparing the nodule structure with the stratigraphy of the related sediments, the following conclusions are drawn concerning the sedimentation processes during the last 4 to 6×106 years: The growth of the nodules started about 4 to 4.5 Ma before present during or near to the end of a period of erosion on a fossil-free, probably Miocene sediment. During the first phase of only a few hundred thousandyears, the nodules grew very quickly (7 to 〉18 mm/Ma). Fe-rich hydrogenetic material formed the internal sections of the nodules during this time. Slowing down of the bottom currents, resulting in deposition of thin sediment covers for short intervals, caused the character of the nodules to change to a more diagenetic composition. The growth rates were reduced to about 1 to 2 mm/Ma. The time of slowing is roughly 3 to 4 Ma BP. Probable uncertainties of the dating and growth rates resulting from supposed changes of the10Be supply to the nodules due to variations of the near bottom environment are discussed.
    Abstract: Résumé Le «Kana Gap» est un chenal sous-marin qui relie les bassins de Sierra Leone et de Gambie, au large de l'Afrique occidentale. Des nodules de manganèse, recueillis le long de profils transversaux dans ce chenal, ont fait l'objet d'une étude chimique et d'une détermination d'âge10Be. La comparaison entre la structure des nodules et la stratigraphie des sédiments sous-jacents permet de tirer les conclusions suivantes relatives au processus sédimentaire au cours des 4 à 6 derniers Ma. La croissance des nodules a commencé il y a environ 4 à 4,5 Ma pendant ou juste après un épisode d'érosion sous-marine sur des sédiments non fossilifères, probablement miocènes. Au cours d'une première phase d'une durée de quelques centaines de milliers d'années, la croissance a été très rapide (7 à 〉 18 mm par Ma) avec formation de la partie centrale du nodule, constituée de matière hydrogénée riche en Fe. Ensuite, après ralentissement des courants de fond et dépôt probable d'une mince couche de sédiment, le caractère des nodules a évolué vers une composition plus diagénétique, avec réduction du taux de croissance à 1 à 2 mm par Ma. Le moment de ce changement de régime doit se situer entre 3 et 4 Ma. Des changements dans les conditions de milieu sur le fond de la mer pourraient avoir provoqué une variation de la quantité de10Be apportée aux nodules, d'où résulterait une incertitude sur l'estimation des âges et du taux de croissance; cette question est discutée par les auteurs.
    Notes: Zusammenfassung An Manganknollen aus der Kane-Lücke, dem Verbindungskanal zwischen Sierra Leone Becken und Gambia Becken (vor W-Afrika) wurden entlang Querprofilen durch mehrere Knollen chemische Untersuchungen und10Be Altersbestimmungen durchgeführt. Durch Vergleich des Aufbaus der Knollen mit der Stratigraphie des unterlagernden Sediments werden Rückschlüsse auf Veränderungen des Sedimentationsgeschehens während der letzten 4–6×106 Jahre gezogen. Hiernach begann das Wachstum der Knollen vor maximal 4.5×106 Jahren während oder gegen Ende einer Erosionsphase auf fossilfreiem, vermutlich miozänem Sediment. Während der ersten Phase wuchsen die Knollen über wenige 100000 Jahre sehr schnell (7 bis〉18 mm/106 Jahre). Hierbei schied sich Fe-reiche Knollensubstanz hydrogener Zusammensetzung ab. Nach Verringerung der Strömung und vermutlich zeitweiser Bildung von dünnen Sedimentschleiern änderte sich der Charakter der Knollen zu mehr diagnetischer Zusammensetzung bei wesentlich reduziertem Wachstum (ca. 1 bis 2 mm/106 Jahre). Der Zeitpunkt der Umstellung ist nur sehr grob zu ermitteln, er dürfte etwa zwischen 3 und 4×106 Jahren vor heute liegen. Eventuelle Unsicherheiten bei der Datierung und den Wachstumsraten, die möglicherweise aus milieubedingten Änderungen in der10Be Versorgung der Knollen resultieren, werden diskutiert.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Low-temperature scanning electron microscopy has been performed for imaging the spatial distribution of the critical current densityj c(x,y) and of the critical temperatureT c(x,y) in polycrystalline superconducting YBaCuO films. Strongly inhomogeneous behavior has been observed, and the spatial resolution limit has been found to be 1–2 μm. The local temperature increment in the specimen film caused by the electron beam scanning has been demonstrated experimentally as the underlying mechanism of the imaging principle, and the beam-induced thermal perturbation of the high-T c film/substrate configuration is discussed in detail. The radiation hardness of the sample films against the electron beam irradiation in our imaging experiments has been evaluated. No radiation damage could be detected up to the maximum applied dose of well above 1020 electrons/cm2 for a typical beam energy of 26 keV.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Molecular biology reports 10 (1985), S. 153-158 
    ISSN: 1573-4978
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Complexes of histone H1 from sea urchin sperm (H1S) and calf thymus (H1T) with superhelical DNA I and relaxed circular DNA II have been analyzed by analytical sedimentation. Similar to H1T, the highly basic and relatively arginine-rich histone H1S preferentially interacts with DNA I compared to DNA II under competition conditions. However, H1S induces a stronger aggregation of bothforms of DNA than H1T. Below 0.05 M NaCl, the soluble complexes formed by both histones have similar properties, but aggregation proceeds in a different manner: H1S induces a stronger aggregation of DNA II as compared to DNA I, whereas H1T fails to aggregate DNA I. The results are explained on the basis of differences in amino acid sequence and structure of the two histones and related to the special chromatin condensing ability of histone H1S.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-0581
    Keywords: volcanology ; hotspot ; Pacific ; Macdonald ; petrology ; Austral Islands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The southeastern extension of the Austral Islands volcanic chain terminates near 29°S, 140°W at the active Macdonald Seamount. The ‘hotspot’ region near Macdonald consists of at least five other volcanic edifices each more than 500 m high, included in an area about 50–100 km in diameter. On the basis of the sea-floor topography, the southeastern limit of the hotspot area is located about 20 km east of the base of Macdonald, where it is defined by the 3950 m isobath. At the edge of the hotspot area, there is a marked deepening of the seafloor from c.3900 m down to 4000–4300 m. The deeper sea-floor is faulted and heavily sedimented. The Macdonald volcano itself stands 3760 m above the surrounding seafloor, and has a basal diameter of 45 km. Its summit in January 1987 was 39 m below sea level, and it seems likely that Macdonald will emerge at the surface in the near future. Recent (March and November 1986) phreatic explosions on Macdonald Seamount erupted fragments of ultramafic and mafic plutonic blocks together with basic lapilli (volcaniclastic sand). The plutonic blocks have been variably altered and metamorphosed, and in some cases show signs of mineralisation (disseminated sulphides). The blocks presumably come from deeper levels in the volcanic system. The volcanics so far dredged from Macdonald consist of olivine and clinopyroxene cumulus-enriched basalts, evolved basalts, and mugearite. On the basis of incompatible element variations, simple crystal fractionation seems to be controlling the chemical evolution of Macdonald magmas.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Grafting of styrene or methyl methacrylate on chlorine containing polyesters of 2,2-bis(4-hydroxyphenyl)-1,1,1-trichloroethane is initiated by titanium(III) chloride and chromium(II) acetate/morpholinocyclohexene or vanadium(III) chloride. Analogous, chlorine containing polcarbonates can be grafted. By using styrene, crosslinked graft copolymers are formed. Their formation is influenced by the gel effect. The influences of structure of the backbone chain and grafting conditions have been investigated.
    Notes: Die Pfropfung von Styren oder Methylmethacrylat auf chlorhaltige Polyester des 2,2-Bis(4-hydroxyphenyl)-1,1,1-trichlorethans läßt sich durch Titanium(III)-chlorid und Chromium(II)-acetat/Morpholinocyclohexen oder durch Vanadium(III)-chlorid initiieren. Analog lassen sich chlorhaltige Polycarbonate pfropfen. Mit Styren entstehen vernetste Pfropfcopolymere, deren Bildung durch den Geleffekt geprägt wird. Der Einfluß der Struktur der Rückgratkette und der Pfropfbedingungen wurde untersucht.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 38 (1987), S. 223-226 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein kurzer Überblick über gebräuchliche Bestimmungsmethoden der Hydrophilie von Polymeren wird gegeben, und die Korrelation dieser charakteritistichen Stoffgröße mit Strukturparametern fester und gelöster Polymere wird diskutiert. Zur Quantifizierung der Hydrophilie löslicher Polymere wird ein neuer durch Trübungstitration ermittelter Parameter vorgeschlagen.
    Notes: In connection with a brief review of usual methods of determining hydrophilicity of polymers, correlations between hydrophilicity and structural parameters of solid polymers as well as dissolved macromolecules are discussed. To quantify the hydrophilicity of dissolved polymers, a new parameter obtained by turbidimetric measurements is submitted.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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