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  • 1
    ISSN: 1432-1939
    Keywords: Forest decline ; Carbohydrates ; Picea abies ; Growth ; Leaf area index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This is the first in a series of papers on the growth, photosynthetic rate, water and nutrient relations, root distribution and mycorrhizal frequency of two Norway spruce forests at different stages of decline. One of the stands was composed of green trees only while the other included trees ranging in appearance from full green crowns to thin crowns with yellow needles. In this paper we compare the growth and carbohydrate relations of the two stands and examine relationships among growth variables in ten plots. The declining stand produced 65 percent of the wood per ground area compared with the stand in which all trees were green because its foliage produced less wood at any level of leaf area index. The difference in foliage efficiency between the sites could not be explained by differeneces in climate, competition or stand structure. The declining stand appeared to have lower carbon gain as indicated by a smaller increase in reserve carbohydrates before bud break, and weaker sinks for carbohydrates as indicated by less use of the stored carbohydrates than the healthy stand. Thus, growth reduction was probably related to factors which affect both photosynthesis and, even more, the sinks for carbohydrate.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1939
    Keywords: Forest decline ; Ectomycorrhizas ; Fine roots ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of root tips and apparent ectomycorrhizas was compared in the Fichtelgebirge (FRG) over one growing season in two 30-year-old Picea abies stands, both on soils derived from phyllite but showing varying symptoms of decline. Visual symptoms of tree decline reflected a lower relative and absolute mycorrhizal frequency, a lower number of ectomycorrhizas per m2 leaf area and an uneven vertical distribution of root tips and ectomycorrhizas. The number of apparent ectomycorrhizas per ground area was correlated with the amount of magnesium, calcium, and ammonium, and the pH in the free-drainage soil solution, and with the molar calcium to aluminium ratio in mineral soil extracts. The foliage concentrations of magnesium and calcium were correlated with the numbers of apparent ectomycorrhizas per m2 leaf or ground area. These observations were used to formulate testable hypotheses concerning the role of the root system and the soil environment in forest decline.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 3553-3561 
    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: A method for the determination of composition and content of pendent double bonds in untreated samples of styrene-ethylene dimethacrylate and styrene-divinylbenzene copolymers from Raman spectra has been developed. By computer treatment of spectra it was shown that Raman spectra are sensitive to the distribution of components in the studied copolymers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1789-1800 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: From the temperature dependence of integrated intensities and from line widths in high-resolution 1H-NMR spectra, the relaxation times T1 and T2 of protons in CH2 and CH3 groups of polyisobutylene in CCl4 solution have been determined. Although the relaxation time T1 of methylene protons is determined mainly by intragroup interactions, intergroup interactions of two methyl groups from each two consecutive monomer units were found to contribute considerably to T1 of methyl protons. The Structure and mobility of polyisobutylene (PIB) molecules in solution is discussed on the basis of the relaxation time data.
    Additional Material: 5 Ill.
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  • 5
    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: Mittels 1H- und 13C-NMR- sowie Ramanspektren wurde gezeigt, daß die Epoxidgruppe von 2,3-Epoxypropylmeth-acrylat (EPMA) in Gegenwart einer großen Glasoberfläche quantitativ gespalten wird, wobei es zur Bildung von 2,3-Dihydroxypropylmethacrylat und einer Reihe von niedrigmolekularen Substanzen mit Doppelbindungen kommt. Die Polymerisation von EPMA in Gegenwart von porösem Glas liefert Poly(2,3-epoxypropyl-methacrylat). Ein Teil dieses Polymers ist am Glas fest gebunden, wahrscheinlich über die Zerlegungsprodukte des EPMA.
    Notes: From 1H- and 13C-NMR and Raman spectra it was found that by the presence of a large surface of glass, the epoxide group of 2,3-epoxypropyl methacrylate (EPMA) is completely decomposed, yielding 2,3-dihydroxypropyl methacrylate and a number of additional low-molecular-weight products with double bonds. Polymerization of EPMA in the presence of porous glass yields poly(2,3-epoxypropyl methacrylate). Part of this polymer is firmly bound to the glass, probably by means of the decomposition product of EPMA.
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 36 (1985), S. 645-648 
    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: Untersucht wurden 1H-FID- und MW4-Spektren vom mit Ethylendimethacrylat und Divinylbenzen vernetztem und mit CCl4, CDCl3 und Benzen gequollenem Polystyren. Die mit Hilfe von Vielimpulscyclen erreichbaren Linienverschmälerungen werden diskutiert und mit denen der MAR-Technik verglichen. Die Temperaturabhängigkeit der effektiven Relaxationszeit T2eff spiegelt die Dynamik lokaler Segmentprozesse wider.
    Notes: 1H-FID and MW4-pulse spectra of polystyrene crosslinked with ethylene dimethacrylate or divinylbenzene and swollen in CCl4, CDCl3 or benzene, are measured. Line-narrowing effects of multiple-pulse sequences are discussed and compared with those of the MAR-technique. The temperature dependence of the effective relaxation time T2eff reflects the dynamics of local segmental processes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 4 (1966), S. 645-651 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 12 (1974), S. 349-353 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 3 (1965), S. 213-219 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 1623-1632 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Association of syndiotactic (s) poly(methyl methacrylates) (PMMAs) in toluene, benzene, and acetonitrile has been studied by NMR spectroscopy, osmometry, and viscometry. It was found that in solutions of highly syndiotactic PMMA in toluene, most of the polymer exists in the associated state. Association takes place by means of stereospecific intermolecular and intramolecular interactions of long parallel syndiotactic sequences. The minimum length of syndiotactic sequences necessary for association of s-PMMA in toluene is 7-8 monomer units. Viscosity data indicate that in dilute solutions the associated structures appear as large formations which do not have the character of compact particles. The formation of the aggregates of PMMA is a relatively slow process. A model of the structure of the aggregates of s-PMMA in toluene is proposed. As compared with that in toluene, the tendency to aggregation in benzene and acetonitrile is negligible. Integral parameters currently used for the characterization of polymer-solvent interaction, like “good” or θ solvent, are not suitable for predicting the tendency of s-PMMA to aggregation. The formation of aggregates evidently has some connection with the effect of the solvent upon the conformational structure of syndiotactic sequences.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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