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  • 1
    Electronic Resource
    Electronic Resource
    Factors influencing the catalytic activity of titanium silicalites in selective oxidations (1991)
    Springer
    Catalysis letters 8 (1991), S. 237-244 
    Details
    ISSN: 1572-879X
    Keywords: Titanium silicalite ; oxidation catalyst ; hydrogen peroxide adsorption ; IR ; DRS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Titanium silicalites synthesized via different procedures are tested in the oxidation of phenol, l-octene and n-hexane by aqueous H2O2. It is shown that the presence of titanyl groups, on which H2O2 is activated by formation of titanium peroxo complexes, is a prerequisite for oxygenation activity. Furthermore, in order to afford high selectivities, titanium silicalites should be free of impurities which cause acid catalyzed side reactions or H2O2 decomposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00764122
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  • 2
    Electronic Resource
    Electronic Resource
    Molecular orientation and structure in ultrathin films of amphiphilic microgel copolymer with the branching of octadecyl groups studied by infrared spectroscopy (1997)
    Springer
    Colloid & polymer science 106 (1997), S. 144-146 
    Details
    ISSN: 1435-1536
    Keywords: IR ; ultrathin films ; LB films ; amphiphilic polymer ; microgel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Molecular orientation and structure in five-monolayer Langmuir-Blodgett (LB) films of an amphiphilic polymer consisting of a flexible hydrophilic epichlorohydrinethylene diamine cross-linking microgels and a number of hydrophobic chains have been studied by infrared (IR) transmission and reflection-absorption (RA) spectroscopy. The downward shifts of the NH and C=O stretching bands show that the amide groups are involved in medium hydrogen bonds. A comparison of the band intensities between the transmission and RA spectra indicates that the hydrocarbon chains are nearly perpendicular to the substrate surface while the C-N bond of the amide group is nearly parallel to the surface. The vibrational frequencies of the two CH2 stretching bands suggest that the LB films have highly ordered alkyl chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01189509
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  • 3
    Electronic Resource
    Electronic Resource
    Spatial Distributions of Biogeochemical Parameters in Surface Sediments (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 497-505 
    Details
    ISSN: 1573-2932
    Keywords: surface sediments ; spatial distribution ; Chl a & c ; C, N & P ; bacterial activity ; Lake Kinneret
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The spatial variability of several sedimentological, chemical and biological parameters in the uppermost layer of bed sediment (ULBS) in Lake Kinneret, was studied during the development of anoxic conditions in the hypolimnion (May, 1995). ULBS samples were taken along a transect from the littoral to the pelagic zones, during the crash of the Peridinium gatunense bloom, about 2 months after the onset of stratification and when oxygen in the hypolimnion was almost completely depleted. The 2-3mm of the ULBS, collected by SCUBA diver, contained relatively fresh material (as shown by high Chl c content) but differed from that of intact Peridinium cells. In the ULBS, the C:N atomic ratio averaged 8 and was similar all over the lake bottom and the average Chlorophyll a:c ratio was 4 (reaching a value of ~7 at 5m). These ratios in Peridinium cells were about 14.3 and 2, respectively. In addition, δ 13C in the organic matter from the ULBS was lighter than that of Peridinium. This data suggests that substantial degredation of the organic matter already occurs in the water column. Grain size distribution suggests the occurance of intense focussing processes in Lake Kinneret. Chemical and biological parameters in the ULBS exhibited clear depth dependent patterns, suggesting changes in physical and chemical processes occur. Three different zones can be distinguished in Lake Kinneret bottom sediments. a. The littoral oxic photic zone (down to 5-7m), which is influenced by intensive biodegredation and high turbulence. b. Transition zone (7-20m), with an oxic-photic gradient and developed focussing processes. c. Profundal, anoxic zone (〉20m), where all fine, settled, organic rich material concentrates and undergoes anaerobic decomposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018303826012
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  • 4
    Electronic Resource
    Electronic Resource
    Spatial distributions of biogeochemical parameters in surface sediments (1997)
    Springer
    Water, air & soil pollution 99 (1997), S. 497-505 
    Details
    ISSN: 1573-2932
    Keywords: surface sediments ; spatial distribution ; Chla &c ; C, N & P ; bacterial activity ; Lake Kinneret
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The spatial variability of several sedimentological, chemical and biological parameters in the uppermost layer of bed sediment (ULBS) in Lake Kinneret, was studied during the development of anoxic conditions in the hypolimnion (May, 1995). ULBS samples were taken along a transect from the littoral to the pelagic zones, during tile crash of thePeridmium gatunense bloom, about 2 months after the onset of stratification and when oxygen in the hypolimnion was almost completely depleted. The 2–3mm of the ULBS, collected by SCUBA diver, contained relatively fresh material (as shown by high Chl c content) but differed from that of intactPeridinium cells. In the ULBS, the C:N atomic ratio averaged 8 and was similar all over the lake bottom and the average Chlorophyll a c ratio was 4 (reaching a value of ∼7 at 5m). These ratios inPeridinium cells were about 14 3 and 2, respectively. In addition, δ12C in the organic matter from the ULBS was lighter than that ofPeridinium. This data suggests that substantial degredation of the organic matter already occurs in the water column. Grain size distribution suggests the occurance of intense focussing processes in Lake Kinneret. Chemical and biological parameters in the ULBS exhibited clear depth dependant patterns, suggesting changes in physical and chemical processes occur. Three different zones can be distinguished in Lake Kinneret bottom sediments a. The littoral oxic pholic zone (down to 5–7m), which is influenced by intensive biodegradation and high turbulence. b Transition zone (7–20m), with anoxic-photic gradient and developed focussing processes c. Profundal, anoxic zone (〉20m), where all line, settled, organic rich material concentrates and undergoes anaerobic decomposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02406889
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Fractionation of linear polyethylene during bulk crystallization under high pressurePresented in part at the Dallas Meeting of the American Physical Society, High Polymers Division, March 1970. (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 2061-2080 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two linear polyethylene fractions (Mη, 11,260 and 100,000) and mixtures of these fractions have been isothermally crystallized from the melt under pressures up to 3000 atm. Characterization of individually crystallized fractions with transmission electron microscopy indicates that pressure can be used to produce a crystallite whose thickness is a measure of the chain length within it. Although the high molecular weight fraction yields spherulites containing individually varying lamellae thicknesses, the maximum thickness of each lamella is a measure of the chain length within it. Both electron micrographs and differential thermal analysis results show that crystallization of homogeneous mixtures of the high and low molecular weight fractions under high pressure results in a distinct fractionation and segregation according to molecular weight.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160091110
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  • 6
    Electronic Resource
    Electronic Resource
    Crystallization of poly(tetramethyl-p-silphenylene-dimethylsiloxane) (TMPS-DMS) block copolymers: Morphology and kineticsPaper presented in part at the IUPAC Meeting, September 10-14, 1973, Aberdeen, Scotland and at the International Microsymposium on Fusion and Crystallization of Polymers, June 1976, Leuven, Belgium.This work was carried out by H. M. Li in partial fulfillment of Ph. D. requirements. (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 1059-1070 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystallization behavior of random block copolymers of (tetramethyl-p-silphenylenesiloxane) and dimethylsiloxane has been studied over a wide range of temperature and composition. The copolymer melting temperature, glass transition temperature, rate of crystallization, crystallinity, and density decrease in magnitude as the dimethylsiloxane block content are raised in this two-component system. The crystal end-surface (interfacial) energy increases as the dimethylsiloxane mole fraction decreases in accord with other morphological observations. The morphological changes observed in these copolymers are consistent with the conclusions deduced from the crystallization kinetics. Negatively, birefringent spherulites are observed over the entire crystallization range investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.180160612
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