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
  • Chemistry  (22)
  • Reversed micelle  (6)
  • Influenza  (2)
  • 71.38.+i  (1)
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 72 (2000), S. 569-573 
    ISSN: 1090-6487
    Keywords: 71.38.+i
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Applying the canonical transformation with the 1/λ perturbation expansion in the nonadiabatic and intermediate regime and the discrete generalization of Pekar’s continuous nonlinear equation in the extreme adiabatic regime, we show that there are no strings in narrow-band ionic insulators due to the Fröhlich electron-phonon interaction alone. The multipolaron system is a homogeneous state in a wide range of physically interesting parameters, no matter how strong the correlations are. At the same time, the Fröhlich interaction allows the antiferromagnetic interactions and/or short-range electron-phonon interactions to form short strings in doped antiferromagnetic insulators if the static dielectric constant is large enough.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of competitive binding of two polyanions - DNA and synthetic fluorescence-tagged poly(methacrylate) (PMA*) - with the polycation-quencher poly(N-ethyl-4-vinyl-pyridinium) (PEVP) was studied by fluorescence quenching technique. It was found that ability of DNA to displace PMA *from the water-soluble nonstoichiometric interpolyelectrolyte complex (NPEC) formed by PMA* and PEVP - NPEC(PMA*-PEVP) - and to form water-soluble NPEC(DNA-PEVP) \documentclass{article}\pagestyle{empty}\begin{document}$$ NPEC(PMA^{*}\hbox{-}PEVP) + DNA \Leftrightarrow NPEC(DNA\hbox{-}PEVP) + PMA^{*}$$\end{document} can be determined by the parameter Ψ = PPMA*/PPEVP where PPMA* and PPEVP are the degrees of polymerization of PMA* and PEVP, respectively. In the case of Ψ 〈 1 the decrease of Ψ leads to the shift of the reaction equilibrium to the right, which can be explained by the gain of entropy due to the increase of the total number of polymeric particles in the solution. Introduction of alkali metal cations into the reaction mixture results in the shift of the reaction equilibrium, and according to their ability to shift the equilibrium to the right the cations can be arranged in the series Na+ 〉 K+ 〉 Li+. The substitution of native DNA by denatured DNA practically does not affect the reaction equilibrium in solutions of NaCl and KCl but considerably shifts it to the right in solutions of LiCl. The data obtained are in accordance with the differences in the selectivity of alkali cations binding with competitive polyanions. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 41-68 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper deals with general and also specific aspects of matrix polyreactions on macromolecular templates, namely, mutual assistance of active centres of propagating chains and template units in elementry steps of propagatior. Such assistance has been found in polymerization of 4-vinylpyridine on polyacids and propargyl compounds on poly-4-vinylpyridine. These examples have shown that these kinds of assistance are the crucial points in kinetic template effects.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 5 (1981), S. 121-154 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The general principles of construction of gel-immobilized catalyst systems (GICS) are reported as well as some peculiarities of the polymerization of ethylene and of the dimerization of ethylene and propylene in the presence of these systems.GICS consist of a transition metal complex and a specially designed polymeric support. Advantages offered by gel-immobilized catalyst systems are discussed with respect to homogeneous and microheterogeneous metal complex catalysts.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 13 (1985), S. 137-155 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Water-soluble nonstoichiometric polyelectrolyte complexes (NPEC) are formed as a result of interaction of opposite charged polyelectrolytes used in nonequivalent ratios. One of the most important properties of NPEC is their ability to participate in intermacromolecular exchange and substitution reactions in aqueous solutions. The kinetics of exchange and substitution reactions has been studied by the method of luminescence quenching. It has been found that such reactions proceed by the contact mechanism and that addition of low molecular electrolytes to the reaction mixtures results in a dramatic increase in the rates of the reactions. The kinetics of the reactions is well described by the equation q = 1-exp(- kt∝) (here q is the degree of conversion and ∝ 〈 1), deduced under the assumption that exchange and substitution occur by the nucleation mechanism and the development of nuclei is inhibited in time. The studied reactions represent a new class of interpolymer reactions and they can be very important, in particular, for understanding the mechanism of functioning of biologically important macromolecules and for the interpretation of the physiological activity of polyelectrolytes.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Interpolymer reactions between poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) and poly(N-tert-butylaziridine) (PTBA) were studied and compared with the corresponding reactions of these polyacids with linear polyethyleneimine (LPEI). In aqueous alkaline and salt media the presence of the bulky non-polar N-substituent in the main chain of PTBA results in a decrease of stability of polyacid-PTBA polyelectrolyte complexes. LPEI, which forms stronger salt bonds with PAA, substitutes PTBA in the PAA-PTBA polyelectrolyte complexes. Addition of simple salts to aqueous solutions of non-stoichiometric polyelectrolyte complexes (N-PEC) PAA-PTBA and PMAA-PTBA at room temperature causes a phase separation due to macromolecular exchange and disproportionation reactions. At elevated temperatures (T = 40 - 60 °C), however, the macromolecular exchange between different N-PEC particles does not occur and phase separation in aqueous salt solution of the N-PEC's PAA-PTBA, PMAA-PTBA is not observed. This is attributed to hydrophobic interactions in polyacid-PTBA complexes due to the presence of the tert-butyl groups in the latter.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2211-2216 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The interaction between oppositely charged linear and crosslinked polyelectrolytes and the molecular mechanism of the transport of linear polyelectrolytes into oppositely charged gels were studied. The mechanism represents a “relay-race” transfer of polyion segments from one fragment of the polyelectrolyte network to the other via interpolyelectrolyte exchange reaction. Thus, the whole layer of the formed interpolyelectrolyte complex serves as an active zone. The driving force for the transport is produced by interpolyelectrolyte addition reaction on the solution/gel interface.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 6 (1984), S. 259-276 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Water-soluble nonstoichiometric polyelectrolyte complexes (N-PEC) constitute a new class of polyelectrolytes. N-PEC are formed as a result of interaction between oppositely charged polyelectrolytes taken in non-equivalent rations and thus they are macromolecular compounds. An N-PEC particle can be represented as a macromolecule of a segmented block copolymer. The behaviour of the N-PEC in aqueous-salt media shows their polyelectrolyte nature, but in contrast to ordinary polyelectrolytes, they undergo considerable conformational changes. These transitions precede phase separations, which are unique and are accompanied by the phenomena of disproportionation. Using N-PEC as enzyme carriers it is possible to produce self-regulating systems with a feedback and also thermostable systems, which are the simplest models of a spore. The N-PEC formed by synthetic polyelectrolytes and some proteins, show a pronounced physiological activity and belong to the class of highly immunogenic antigens.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 1057-1062 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The competitive binding of fluorescence-tagged poly(methacrylate) polyanions and poly(phosphate) polyanions with different poly(N-alkyl-4-vinylpyridinium) polycation quenchers (alkyl = methyl, ethyl and propyl) was studied in the region 278÷333 K by fluorescence quenching technique. The equilibrium of this interpolyelectrolyte substitution reaction proved to be temperature sensitive except in the case when the poly(N-methyl-4-vinylpyridinium) polycation was used. Thermodynamic parameters of the reaction were determined. The possibility of effective temperature control of the interpolyelectrolyte reaction might be important for understanding, prediction and utilization of transformation processes of complex particles formed by electrostatically complementary (biological) macromolecules.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    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: Poly(propargylpyridinium chloride), poly(propargy1-4-vinylpyridinium chloride), poly(propargyl-2,2-bipyridinium chloride), poly(propargyl-1-methyl-2,2-bipyridinium methylsulfate chloride), poly(N-ethyl-vinylpyridinium bromide), and poly(propargyl-2-hydroxyquinolium chloride) were synthesized and a number of simple and complex, tetracyanoquinodimethane ionradical polyelectrolytes were prepared from them. An attempt was made to understand how the molecular structure of these compounds manifests itself in their observed electrophysical properties. Our results show increased electroconductivity in cases of simple and complex ion-radical polyelectrolytes where the conjugated bond polymer “backbone” is in close proximity to dipyridyl polarizing side groups.
    Additional Material: 3 Tab.
    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...