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  • 1
    Electronic Resource
    Electronic Resource
    A frequency divider with a small output pulse delay (1974)
    Springer
    Measurement techniques 17 (1974), S. 418-419 
    Details
    ISSN: 1573-8906
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Conclusions A method has been described for designing a frequency divider with a small output pulse delay, which may find uses in computers and data handling systems. The device functions well over the range −15 to +55°C and is highly reliable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00812855
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  • 2
    Electronic Resource
    Electronic Resource
    Molekulargewichte bei den Ceiling- und Floor-Temperaturen (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 618-618 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01639347
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  • 3
    Electronic Resource
    Electronic Resource
    Einfluß von CO2 auf die NCA-Polymerisationen (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 711-711 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01784479
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  • 4
    Electronic Resource
    Electronic Resource
    Molecular weights at ceiling and floor temperatures (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 3465-3470 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021771130
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  • 5
    Electronic Resource
    Electronic Resource
    Stereosequencing in poly(leucine) obtained from stereoselective polymerization of racemic leucine N-carboxy anhydride (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 463-474 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of mixtures of D- and L-isomers of α-amino acid N-carboxy anhydrides follow normal copolymerization behavior, and sometimes even ideal copolymerization, which is conventionally interpreted as leading to a random distribution of monomer units along the polymer chains. Equations are dereived which relate the fraction of isotactic L-diads to experimental data from the previously reported methods involving sequential and stereospecific cleavage with enzymes. The application of these equations to poly(D,L-leucines), which were prepared by polymerization of racemic leucine N-carboxy anhydride with chiral and achiral primary amines as initiators, indicated that the polymers contain between 94 and 98% isotactic diads. The poly(leucines) thus consist of long stereoblocks despite the observed ideal copolymerization behavior.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790221
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  • 6
    Electronic Resource
    Electronic Resource
    Syndiotactic poly(leucine) (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 579-590 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: N-(tert-Butoxycarbonyl)-L-leucyl-D-leucyl-L-leucyl-D-leucine tetrapeptide was synthesized from L- and D-leucine α-amino acids by conventional coupling methods. This tetrapeptide was transformed into an activated (polymerizable) tetrapeptide by conversion to the pentachlorophenyl ester and subsequent removal of the tert-butoxycarbonyl group. Condensation polymerizations of the activated tetrapeptide were performed in various solvents with triethylamine and N,N-diethyl-1-amino-2-propanol bases. Molar masses (“molecular weights”) of the resulting polymers were estimated to be in excess of 34000 g/mol. From optical rotation measurements in trifluoroacetic acid solution, it was found that the polymers were highly syndiotactic, although a small amount of isomerization (0,9-2,1%) occurred to yield polymers with a small excess of L-leucine residues. The degree of isomerization decreased with decreasing base strength and concentration and with decreasing polarity of the solvent; these effects were explained in terms of the simultaneous enolization and/or oxazolone-formation reactions.Preliminary studies of the conformation of syndiotactic poly(leucine) were performed with X-ray diffraction, NMR, IR and optical rotation methods. It was concluded that syndiotactic poly(leucine) most probably exists in a π-helical conformation with a preferred screw sense in both the solid state and in chloroform solution. NMR and optical rotation data on solutions in trifluoroacetic acid/chloroform showed that the polymer exhibits a conformational transition in the region of 4-10% trifluoroacetic acid content.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790303
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  • 7
    Electronic Resource
    Electronic Resource
    Study of radical polymerization by means of ESR, 2.Part 1: cf.1. Homogeneous polymerization of methyl methacrylate and vinyl acetate (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 2875-2880 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Für die Bestimmung der stationären Konzentration von Makroradikalen bei der homogenen Polymerisation wurde ein sehr wirksames ESR Spektrometer eingesetzt. Aus den erhaltenen Daten wurden die Geschwindigkeitskonstanten des Kettenwachstums und Kettenabbruchs für die Polymerisationen von Methylmethacrylat und von Vinylacetat auf direktem Weg erhalten. Die Aktivierungsenergien diese Elementarreaktionen wurden gemessen.
    Notes: A very efficient ESR spectrometer was applied to the measurement of the stationary concentration of macroradicals in homogeneous polymerization. From these data the rate constants of chain propagation and chain termination for the polymerizations of methyl methacrylate and vinyl acetate were found in a direct way. Activation energies of these elementary reactions were measured.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021751008
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  • 8
    Electronic Resource
    Electronic Resource
    Carbon dioxide influence on NCA polymerizations (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 603-607 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1977.021780229
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  • 9
    Electronic Resource
    Electronic Resource
    Polymer composites through in situ matrix formation (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 141-146 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Nylon 66 graphite composites have been prepared by the in situ polymerization of the monomer epitaxially crystallized onto the fiber surface. Nylon 66 monomer, whether oriented (crystallized from solution) or unoriented (deposited from an aqueous slurry) was found to polymerize to an oriented composite by a variety of techniques (spark discharge, resistance heating, and furnace heating). X-ray diffraction has demonstrated that the matrix orientation corresponds to the polymer chains aligning themselves with the graphite crystal edges along the fiber axis. Scanning electron microscopy of fracture surfaces has shown excellent adherence between the fiber and matrix with fracture occurring mostly in the matrix material.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190111
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  • 10
    Electronic Resource
    Electronic Resource
    γ-Radiation-initiated post-polymerization of methacrylic acid in the solid statePresented at the 164th National Meeting of the American Chemical Society, New York, September 1972. (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 3003-3016 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solid-state postpolymerization of slowly crystallized methacrylic acid was studied at 0°C with 60Co γ-radiation as the initiator. The yield, molecular weight, molecular weight distribution, and stereosequencing of the polymer product were determined as a function of polymerization time. The narrow molecular weight distribution and the linear dependence of molecular weight on polymer yield were attributed to a polymerization mechanism characterized by both independent chain propagation and essentially no termination step. The overall polymerization rate was substantially faster than that reported previously for shock-crystallized monomer, a result which was attributed to termination by the occlusion of propagating radicals at defects in the shock-crystallized monomer. Although largely atactic, the polymer synthesized in the solid state contained a secondary kind of stereosequencing; the meso triad probability was highest at the end of the chain, where propagation had initiated and decreased continuously with chain growth. The gradient in stereosequencing along the chains was attributed to defects that were introduced into the monomer crystals by the growing polymer chains.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.170101018
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