ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Preparation and electrical and magnetic properties of Sr2-xNaxCuO3 (0 ≤ x ≤ 1) solid solutionsDedicated to Professor Rudolf Hoppe on his 70th Birthday (1992)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 616 (1992), S. 201-207 
    Details
    ISSN: 0044-2313
    Keywords: Mixed-valence copper(II,III) oxide ; solid solutions ; semiconducting behavior ; electronic structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Präparation sowie elektrische und magnetische Eigenschaften der festen Lösungen Sr2-xNaxCuO3 (0 ≤ x ≤ 1)Die festen Lösungen Sr2-xNaxCuO3 (0 ≤ x ≤ 1) mit Kupfer(II,III)-oxid wurden durch Feststoffreaktionen in Sauerstoffatmosphäre dargestellt. Alle diese festen Lösungen haben die Struktur von Sr2CuO3 (Raumgruppe Immm). Elektrische Leitfähigkeits- und EMK-Messungen zeigen Halbleiterverhalten im gesamten Bereich der Zusammensetzung. Die Elektronenstruktur des Sr2CuO3 wird mit der des La2CuO4 auf Basis eines ionisch-kovalenten Modells verglichen. Die Interpretation des Transportverhaltens deutet auf kleine Polaronen. Magnetische Suszeptibilitäts- und EPR-Messungen zeigen, daß die antiferromagnetische Ordnung des Sr2CuO3 abnimmt mit zunehmendem x. Die magnetischen Wechselwirkungen sind jedoch noch stark bei einer Kupferionen- Konzentration von x = 0,8.
    Notes: Mixed-valence copper(II/III) oxide solid solutions Sr2-xNaxCuO3 (0 ≤ x ≤ 1) have been prepared by solid-state reactions in oxygen atmosphere. All solid solutions exhibit the structure of Sr2CuO3 (S.G. Immm). Electrical conductivity and thermoelectric power measurements show a semiconducting behavior in the whole composition range. The electronic structure of Sr2CuO3 is compared with that of La2CuO4 on the basis of an iono-covalent model. Interpretation of transport properties suggests the formation of small polarons. Magnetic susceptibility and EPR measurements show that the antiferromagnetic ordering of Sr2CuO3 tends to vanish as x increases, however magnetic interactions are still strong for a concentration of Cu2+ ions corresponding to x = 0.8.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19926161033
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Induction of helicity in polyuridylic acid and polyinosinic acid by silver ions (1980)
    New York : Wiley-Blackwell
    Biopolymers 19 (1980), S. 539-556 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silver ions binding to poly(U) and poly(I) produce highly ordered multistranded helices under conditions which would otherwise lead to random coils. Evidence for helicity comes from the hypochromicity and high ellipticity generated in the polymers by Ag+ binding, as well as from x-ray studies and from the cooperativity of the Ag+ complexing reaction. Continuous variation studies show that both polymers form 1:1 and 2:1 polymer-Ag+ complexes. Low pH favors the 1:1 complex with poly(U) and the 2:1 complex with poly(I); the reverse is true at high pH. Ag+ binding and proton-release experiments make it clear that at low pH, unprotonated electron-donor groups are complexed preferentially, but that at high pH, Ag+ readily displaces H+ from protonated groups. In poly(I) the unprotonated donor is N(7), leading at low pH to a 2:1 complex containing N(7)-Ag-N(7) bonds; at high pH, proton release from N(1) leads to a 1:1 complex containing N(1)-Ag-O bonds. In poly(U) there is no unprotonated donor; the low-pH 1:1 complex involves deprotonation of only one N(3) per bound Ag+, leading to N3-Ag-O bonding, while high pH causes deprotonation of two N(3) per Ag+ and a 2:1 N(3)-Ag-N(3) complex. Thus silver ions react with the nucleotide bases in chemically predictable ways, and the formation of different Ag-nucleotide bonds leads to different multiple-helix structures.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1980.360190308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Formation of ψ(+) and ψ(-) DNA (1984)
    New York : Wiley-Blackwell
    Biopolymers 23 (1984), S. 325-335 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: DNA molecules can be organized into ordered aggregates of opposite handedness by complexation with polylysine and other polypeptides; we have investigated the conditions under which ψ(+) and ψ(-) structures are produced with double-helical synthetic polynucleotides. Both poly(dGdC)·poly(dGdC) and poly(dAdT)·poly(dAdT) readily form ψ(-) structures with polylysine, although the method of preparation can alter the CD spectra. The GC copolymer, which is more susceptible to conversion into A or Z conformers, forms ψ(+) structures with lysine-alanine copolypeptides more readily than the AT copolymer. Nucleotide base modifications that favor the Z structure, such as bromination and methylation, also favor ψ(+) formation, and the Co(NH3)6Cl3 reagent that readily induces the Z structure also leads to ψ(+). Thus, the production of the ψ(+) structure seems to be frequently correlated with susceptibility to A or Z formation, although there are some cases in which the B conformer also leads to ψ(+). Polyethylene glycol generally produces a ψ(-) structure; the differentiation between ψ(+) and ψ(-) structures seems to require electrically charged polymers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360230211
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ethanol fermentation of cassava starch pretreated with alkali (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 627-630 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260280424
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...