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  • 1
    ISSN: 1432-0630
    Keywords: 68.35.Fx ; 68.60.Dv ; 68.65. + g
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Platinum-carbon multilayer mirrors with a bilayer spacing of 50 Å were fabricated in an ultrahigh vacuum electron beam evaporator. The thermal stability of these multilayers was studied under vacuum annealing using X-ray reflectivity and X-ray diffraction. Up to 450°C, the bilayer spacing increases monotonically accompanied by a gradual increase in crystallite size and grain texture. At 500°C multilayer reflection vanishes, platinum crystallites grow abruptly, and there is a strong texture of platinum in the [220] -plane. Possible reasons for thermally induced structural modifications in these multilayers are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 2247-2250 
    ISSN: 0887-624X
    Keywords: polymer catalyst ; formose reaction ; thiazolium salt ; hydrocarbons ; dihydroxy acetone ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thiazolium salt polymers synthesized by quaternization of 4-(4′-vinylphenyl)thiazole (VPT) polymers with methyl iodide had a highly catalytic activity for “the formose reaction.” Their catalytic activities were comparable to that of a low molecular weight analog, 3-methyl-4-phenylthiazolium iodide (MPTI). In the reaction catalyzed by the polymer catalyst, a main product, dihydroxyacetone (DHA), was detected by gas-liquid chromatography. The polymer catalysts were easily recovered from the reaction mixture and reused with a sustained catalytic activity. © 1992 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1711-1717 
    ISSN: 0887-624X
    Keywords: durable catalyst ; thiazolium salt ; aqueous system ; acyloin condensation ; enzyme model ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We characterized three low-molecular-weight thiazolium salt analogues: N-methyl-5-(2′-benzyloxyethyl)-4-methylthiazolium iodide (MBMTI), N-methyl-4-phenylthiazolium iodide (MPTI), and N-methylbenzothiazolium iodide (MBTI). MBMTI, having high-electron density on the thiezolium ring, was found to be a durable thiazolium salt in buffer solution. Then, the polymer-supported thiazolium salt catalyst having MBMTI structure as a catalytic site for acyloin condensation was prepared by the polymerization of the corresponding thiazole monomer and the following quaternization. The polymer catalyst had excellent catalytic activity even in buffer solution, while the corresponding low molecular weight catalyst did not show any activity in aqueous system. Furthermore, the durable polymer catalyst could be reused under the aqueous condition. © 1994 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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