ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • mesomorphism  (1)
  • soil microflora  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inorganic and organometallic polymers and materials 6 (1996), S. 313-324 
    ISSN: 1572-8870
    Keywords: Polydiethylphosphazenes ; mesomorphism ; nuclear magnetic resonance ; Transfer of Populations in Double Resonance (TRAPDOR)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The existence of mesomorphism in polydiethylphosphazene was recently established by MAS NMR and X-ray diffraction characterization. In the present work the mechanism of motion of the ethyl side groups in the high-temperature polymorph tabove 45 C) is identified and compared to the arrangement of side groups in the low-temperature polymorph. For this purpose a few NMR active nuclei (13C,14N, and2H) were exploited to define the side-chain motions occurring at transition. Experiments performed at varying temperatures close to the onset of solid transition suggest the presence of jumps between two conformations in the pretransition state. Rotor-synchronized triple-resonance NMR of the high-temperature phase determined the average distances between the carbons and the nitrogens in the polymorphs. The theoretical prediction of the dipolar interaction between the nuclei supports the hypothesis that ethyl groups can undergo a complete rotation about the P CH2 bond by jumping across a conformational barrier. The mechanism of motion of the ethyl groups must be cooperative and the collapse of the rigid shell around the main chain is described at the transition.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 106 (1988), S. 253-261 
    ISSN: 1573-5036
    Keywords: compost treatment ; crop production ; Helianthus annuus L. ; mineral fertilization ; pot-culture experiment ; sandy soil ; soil chemistry ; soil microflora
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of the addition of compost, prepared from vegetable market refuse and stomach contents of slaughtered cattle, were studied in a sandy soil contained, in pots and kept in a greenhouse environment. Comparison was made between: i) a treatment involving pots containing compost mixed with 5% soil, ii) four treatments in which increasing quantities of compost homogeneously taken from the same lot (0, 10000, 20000, 30000 kg ha−1) were integrated with NPK mineral fertilizer to equalize available nutrients; iii) an untreated control. At 3, 4, and 5 years from the date of treatment, after various other crops, sunflower was planted. The yield obtained, though it fell off from year to year, was approximately double in the case of 95% compost. The other four treatments also resulted in production increases compared with the untreated control. Production was found to rise progressively with increasing quantities of compost. The improvement in soil chemistry and microbiology, as shown by analyses performed 5 years after treatment with compost, suggests that the rise in crop production may be attributed to an overall improvement in all components involved in the fertility of the soil used, in our experimental conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...