Library

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
    Production of N, H, and NH active species in N2-H2 dc flowing discharges (1995)
    Springer
    Plasma chemistry and plasma processing 15 (1995), S. 721-731 
    Details
    ISSN: 1572-8986
    Keywords: Laser-induced fluorescence ; flowing dc discharge ; N2-H2 mixture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Densities of N, H, and NH active species have been detected by laser-induced fluorescence (LIF) in N2-xH2 dc flowing discharges. A peak value of N atom densities far x = 0.2–0.5% and a plateau value of H atom densities between x = 1% and 90% in post-discharge conditions (Δ∼0.05 sec, p = 2 torr) has been found. Comparison between LIF measurements of N atoms and the trend of the N2(B, v = II) population shows that the emission from this state can be used for monitoring N atoms. The NH radical has only been detected inside the discharge region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447069
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    CN chemiluminescence in N2 + CH4 Flowing afterglow at low temperatures (1994)
    Springer
    Plasma chemistry and plasma processing 14 (1994), S. 197-208 
    Details
    ISSN: 1572-8986
    Keywords: Nitrogen afterglow ; CN chemiluminescence ; recombination ; hydrocarbon trace detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The spectra of flowing microwave post-discharge excited in N2 and N2 + CH4(N2 + C2H2) gas mixtures have been studied at low temperature (77 K). The molecular spectra of CN emitted by the collision-induced N + C and N + CH chemiluminescent reactions in the low-temperature afterglow system have been thoroughly investigated. The intensity of different CN (B2Σ+-X2Σ+) vibrational bands is very sensitive to low hydrocarbon concentration in nitrogen used as the working gas. Detection of hydrocarbon species has been demonstrated from concentrations of CH4 and C2H2 in N2 greater than 1010 molecules · cm−3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447078
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Rheology of galactomannan-borax gels (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 2445-2461 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rheological behavior of semidilute galactomannan solutions in the presence of borax has been studied. The effects of polymer and borate concentrations, ionic strength, pH, and temperature are investigated and discussed. The shape of the viscoelastic functions of galactomannan-borax gels is similar to that for semidilute or concentrated polymer solutions. In 1 M NaCl, electrostatic effects are screened and the characteristic moduli of the gels appear to be determined by the number of interchain crosslinks. The elastic plateau modulus varies linearly with the free borate concentration and with the 2.6 power of the galactomannan concentration. Time-temperature type superposition is applicable if a vertical shift is introduced to account for the exothermic nature of the complexation reactions. Moreover, it seems possible to control the gel reversibility and the lifetime of crosslinks by changing the complexation kinetics via the pH.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1990.090281301
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Counterion selectivity in cationic polyelectrolytes (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 649-661 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Chloride ion activity coefficients in aqueous solutions of several cationic copolymers have been determined using ion-selective electrodes in both the absence and the presence of simple univalent and divalent salts. Without added salt, the activity coefficient depends on the polymer concentration. It increases with increasing concentration of the added salt. The extent of interaction between counterions and polyions at a given polymer concentration, as estimated form chloride anion activity, is greater for bivalent than for univalent anions. Experimental data are in good agreement with theory. Selective interaction of anions with the ammonium copolymers has also been evidenced by viscometry. The selectivity follows the order \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Cl}^ - 〈 {\rm NO}_3^ - 〈 {\rm oxalate},{\rm fumarate} 〈 \hbox{benzene disulfonate} $$\end{document} For organic anions, in addition to electrostatic interactions, hydrophobic effects, which depend on the structure of the copolymer, play a significant role.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260315
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Thermal behavior of ungrafted and grafted bagasse and wood pulps (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1603-1614 
    Details
    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: The effect of grafting of methyl methacrylate (MMA) and acrylonitrile (AN) on the thermal behavior of the pulp of sugar cane loaded with CaCO3 and the pulp of a broad-leaved tree has been studied by thermal methods. Different experimental conditions of grafting AN onto the eucalyptus pulp have been used, including both water and organic solvent systems as the medium of reaction. To optimize the grafting of MMA onto wood pulp, the effect of pulp swelling and the contact time of the monomer with the pulp have been examined. Ungrafted as well as grafted cellulose samples with different levels of grafting were characterized by differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA). The CaCO3 filler makes the pulp of bagasse thermally more stable. The grafting of MMA onto the bagasse or the wood pulps improves their thermal stability. This is not the case for wood grafted with poly(AN). The thermal stability of the grafted and ungrafted samples varies after a few weight percent has been lost. The glass transition temperature (Tg) of the copolymers have been measured and they are in good agreement with the calculated data. © 1993 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490911
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Viscosity behavior of poly(glyceryl methacrylate) in the presence of borate and phenylboronate ions (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 1015-1022 
    Details
    ISSN: 0887-6266
    Keywords: complexing polymer ; solution viscosity ; poly(glyceryl methacrylate) ; borate ion ; phenylboronate ion ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscosity behavior of polyelectrolyte solutions induced by borate or phenylboronate complexation with poly(glyceryl methacrylate) (PGM) has been investigated. In dilute solutions borate ions can form monodiol (1/1) complexes and didiol (2/1) intramolecular complexes. Both types of complex are anionic. Thus, the polymer is characterized by the existence of charged sites on the chain and loops formed by intramolecular complexation. On the contrary, phenylboronate can only give monodiol 1/1 complexes. In the presence of passive salt, the charges are screened. By addition of borate ion to a PGM solution, a decrease of the initial polymer viscosity due to loop formation is first observed, then the anionic charges fixed on the chain by complex formation induce an expansion of the polyelectrolyte and the viscosity of the solution increases. The situation is different for the PGM-phenyl boronate system, where no intramolecular crosslink is present. In this case the viscosity of the solution increases with phenyl boronate concentration. But for a fixed complexing ion concentration it will tend to that of the neutral polymer when NaCl is added. ©1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090330704
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Swelling of anionic and cationic starch-based superabsorbents in water and saline solution (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 39 (1990), S. 11-29 
    Details
    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: Starch graft superabsorbents were prepared by graft copolymerization either with polyacrylonitrile (PAN) and saponification of the resulting copolymer or with trimethyl-aminoethylacrylate chloride (CMA) and methylene bisacrylamide as crosslinking agent. The influence of several structural parameters on the swelling properties of these absorbents have been studied: crosslink density, ionic content, and composition of the starch. As expected, the absorbency decreases with an increase of the crosslink density. It increases with the ionic content of the graft copolymer up to a maximum, an excess of charges leading to a swelling decrease. The PAN branch length depends on the origin of the starch. High molar weight PAN was grafted onto waxy corn, a starch with high amylopectin content. The swelling increases with increasing molar weight of PAN up to 5 × 105. In saline solution the absorbency of both ionic gels decreases significantly. However, in the presence of multivalent ions their behavior is different. For cationic absorbents the swelling depends on the ionic strength but not on the ion valency. On the other hand, anionic absorbents are significantly affected by multivalent cations.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070390102
    Library Location Call Number Volume/Issue/Year 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...