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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 6230-6230 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Multilayer Fe/Tb films were produced by rf sputtering. The thickness ratio of the Fe and Tb single layers was chosen in such kind to give an overall concentration of about 20 at. % Tb. Homogenous amorphous films of such a composition are well known for their perpendicular anisotropy. The investigations in the magnetic properties revealed that the multilayer films showed perpendicular anisotropy much stronger than the homogenous amorphous films. The maximum of the perpendicular anisotropy was found for multilayers with thickness combination of the single layers tFe=1.0 nm, tTb=1.5 nm. The perpendicular anisotropy increases strongly with increasing substrate temperature during rf sputtering. From the results of VSM measurements of the magnetic moment of the samples we must conclude that the Tb single layers are magnetically ordered even at room temperature. The magnetic moment of the Tb film is antiparallel coupled to the moment of the Fe film. The range of the coupling is at least 2 nm. As long as the multilayer films with various thicknesses of the single layers show perpendicular anisotropy, this anisotropy is rather independent of the thickness of the Tb layers but shows a linear dependence of the reciprocal of the thickness of the Fe layers. The magnetic investigations were accompanied by structural investigations. X-ray diffraction shows very clearly the superlattice of the multilayer films. Observations of cross sections of the multilayers by high-resolution electron microscopy revealed very sharp interfaces between Fe and Tb. The Tb films are crystallographically well ordered, whilst the Fe films showed only a nanocrystalline order. Mösbauer investigations are carried out to give an insight in the influence of the Tb films on the hyperfine field at the Fe atoms.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 56 (1991), S. 4098-4112 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 24 (1991), S. 256-263 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 24 (1991), S. 740-746 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Transient small-angle neutron scattering (SANS) experiments on sheared aqueous surfactant solutions of trimethyl(tetradecyl)ammonium salicylate (TTMA-Sal) are reported. A 0.005 M solution without shear shows a weak correlation peak. For steady shear rates above a threshold value of Γ = 50 s−1 the scattering pattern shows an abrupt increase in anisotropy which is related to a shear-induced structure transition. The analysis of the anisotropic pattern reveals the existence of two types of micelle: short rodlike micelles which are weakly aligned and very long rodlike aggregates which are strongly aligned and which are only present for Γ above the threshold value. We report results on transient SANS measurements in which the shear rate was changed stepwise from a value of 400 s−1 to zero. It is found that the smaller micelles are randomized in orientation, whereas the longer ones do not change orientation at all but their concentration vanishes. The number of surfactant molecules bound in the smaller micelles (type I) increases with time, whereas the number of surfactants bound in the larger ones (type II) decreases. The sum of both remains constant. The number of surfactant molecules bound in type II micelles decays exponentially with a half life of T1/2 = 1.7 (1) s.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 22 (1991), S. 427-433 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: It is the aim of the investigations on a PBTP-glass-spherecomposite to get experimental well-founded informations about the state of stress in the polymer matrix of the composite. The used method was the x-ray-lattice strain-stress measurement.The result of the measurements is the proof of a 3-axial state of tension stress in the polymer matrix in the unloaded state as well as under an uniaxial tension load. The reason are differences in the elastic properties of the two components in this heterogenous built up composite.
    Notes: Die Untersuchungen an einem PBTP-Glaskugel-Verbundwerkstoff haben das Ziel, experimentell begründete Aussagen über den Spannungszustand in der Polymermatrix des Verbundwerkstoffes zu gewinnen. Als Meßverfahren wurde die röntgenographische Spannungsmessung verwendet.Im Ergebnis der Messungen konnte in der Polymermatrix des Verbundwerkstoffes sowohl im unbelasteten Zustand als auch bei einachsiger äußerer Zugbeanspruchung ein mehrachsiger Zugspannungszustand nachgewiesen werden. Er ist durch die Unterschiede in den elastischen Eigenschaften der beiden Komponenten des heterogenen aufgebauten Verbundwerkstoffes bedingt.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 1213-1220 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of methyl 2-(1-hydroxyalkyl)prop-2-enoates 1 with conc. HBr solution afforded methyl (Z)-2-(bromomethyl)alk-2-enoates 2, which were transformed regioselectively into N-substituted methyl (E)-2- (aminomethyl)alk-2-enoates 3 (SN2 reaction) and into N-substituted methyl 2-(1-aminoalkyl)prop-2-enoates 4(SN2′ reaction). Regiocontrol of nucleophilic attack by amine was accomplished simply by choice of solvent, the SN2 reaction occurring in MeCN and the SN2′ reaction in petroleum ether. Hydrolysis and lactamization afforded β-lactams 7 and 8, containing an exocyciic alkylidene and methylidene group at C(3), respectively.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2147-2147 
    ISSN: 0009-2940
    Keywords: Tricyclo[3.3.0.03,7]octanes ; Samarium iodide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,5-Dimethylbicyclo[3.3.0]octan-3,7-dione (2) was converted into 1,5-dihydroxy-3,7-dimethyltricyclo[3.3.0.03,7]octane (3) in the presence of Sml2 in 76% yield.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1673-1675 
    ISSN: 0009-2940
    Keywords: Tricyclo[4.3.1.12,5]undec-3-en-10-ones ; Cyclodehalogenation, intermolecular ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of tricyclo[4,3,1.12,5]undec-3-en-10-ones has been scaled up. By using the improved procedure a number of tricyclic compounds have been obtained for the first time.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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