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  • 1
    Electronic Resource
    Electronic Resource
    Approximation by finite differences of the propagation of acoustic waves in stratified media (1989)
    Springer
    Numerische Mathematik 54 (1989), S. 655-702 
    Details
    ISSN: 0945-3245
    Keywords: AMS(MOS): 65N05 ; CR: G1.8
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary In this paper, we analyze the approximation of acoustic waves in a two layered media by a finite diffrences variational scheme. We examine in particular the approximation of the guided waves. We point out the existence of purely numerical parasitic phenomena and quantify the numerical dispersion relative to guided waves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01396488
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetic analysis of the swimming behaviour of bluegill sunfish, Lepomis macrochirus Rafinesque, exposed to copper: hypoactivity induced by sublethal concentrations (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 33 (1988), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The concentration of copper which caused 50% mortality of bluegill in 96 h (96-h LC50) was between 4 and 16 ppm of the metal, copper. During the 6–8 day treatment period, sublethal concentrations of copper elicited a hypoactive locomotor response which was dependent on both concentration and time of exposure. Fish treated in 0.04, 0.08 and 0.4 ppm of copper were only 67, 61 and 44% as active, respectively, as they were prior to treatment. Locomotor activity decreased dramatically during the first 4 days of exposure to copper and remained low during further exposure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1988.tb05503.x
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  • 3
    Electronic Resource
    Electronic Resource
    Semi-classical asymptotics in solid state physics (1988)
    Springer
    Communications in mathematical physics 116 (1988), S. 401-415 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract This article studies the Schrödinger equation for an electron in a lattice of ions with an external magnetic field. In a suitable physical scaling the ionic potential becomes rapidly oscillating, and one can build asymptotic solutions for the limit of zero magnetic field by multiple scale methods from “homogenization.” For the time-dependent Schrödinger equation this construction yields wave packets which follow the trajectories of the “semiclassical model.” For the time-independent equation one gets asymptotic eigenfunctions (or “quasimodes”) for the energy levels predicted by Onsager's relation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01229201
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  • 4
    Electronic Resource
    Electronic Resource
    Characterization of particle surface and morphology in vinyl acetate-butyl acrylate emulsion copolymers — Influence of the copolymerization pathway (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 791-802 
    Details
    ISSN: 1435-1536
    Keywords: Vmyl acetate-butyl acrylate emulsion copolymers ; surface end-groups ; soap titration method ; particle morphology ; emulsion process
    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 Surface characterization was investigated in vinyl acetate (VAc) butyl acrylate (BuA) copolymer latexes of various compositions and prepared with four different emulsion polymerization processes: conventionnal batch, composition-controlled batch, core-shell, emulsifier-free semi-continuous. Surface end-groups (sulfate or carboxylic) titration results were first compared and discussed according to the type of process and as a function of conversion. As previously shown [1], it was confirmed that batch latex particles present a heterogeneous structure with a rich VAc outlayer, as in core-shell particles. As expected, semi-continuous and composition-controlled batch particles exhibit surface end-group characteristics revealing a more homogeneous distribution of both monomers within the particles. These differences in particle morphology were corroborated by analyzing water-polymer interface in these latexes using the soap titration method, with the sodium dodecyl sulfate (SDS) or sodium hexadecyl sulfate (SHS) as emulsifier probes. When the BuA was batch-polymerized onto PVAc seed particles, the estimated surface composition seemed to show that probably phase rearrangement occurs in the particle during the synthesis or upon aging. It was also confirmed that SDS displays an abnormal adsorption due to complexation and solubilization in the rich-VAc shell of the particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01418455
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  • 5
    Electronic Resource
    Electronic Resource
    Valence and inner proton hole states in119in via the (d,3He) reaction (1989)
    Springer
    The European physical journal 334 (1989), S. 133-141 
    Details
    ISSN: 1434-601X
    Keywords: 21.10.−Jx ; 21.10.Pc ; 25.45.−6h
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Proton holes states have been studied up toE x=17 MeV andE x=3.5 MeV in the119In nucleus via the120Sn(d,3He)119In reaction respectively atE d=108.4 MeV andE d=51 MeV. DWBA analysis of angular distributions has allowedl attributions for a large number of new levels and the determination of valence and inner hole strength distributions. The first 1g 9/2, 2p 1/2 and 2p 3/2 levels only exhaust 40%, 60% and 32% of their respective sum rule limits. The missing strengths are shared among several low lying levels and significant higher lying contributions. The 1f strength, not identified in the previous experiments is spread fromE x=1 MeV to about 17 MeV. The low lying levels aroundE x=2.4 MeV could exhaust some 40% of the 1f 5/2 sum rule. The higher lying strength with a flat maximum aroundE x=7.5 MeV could account for the 1f 7/2inner hole strength and the missing 1f 5/2 valence strength. The experimental strength functions compare rather well with the predictions of the quasiparticle-phonon model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294214
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  • 6
    Electronic Resource
    Electronic Resource
    Preface (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 10 (1985), S. XIII 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020101985101
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  • 7
    Electronic Resource
    Electronic Resource
    Preface (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 10 (1985), S. XVII 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020101985102
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  • 8
    Electronic Resource
    Electronic Resource
    Batch emulsion copolymerization of n-butyl acrylate and methyl methacrylate in the presence of a nonionic surfactant (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 10 (1985), S. 43-57 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Batch emulsion copolymerization studies of n-butyl acrylate and methyl methacrylate have been investigated using potassium persulfate as initiator and a nonionic surfactant (REWOPAL HV 25) as emulsifier. Higher polymerization rates, shorter nucleation stage and complete conversion are obtained by comparison to the SDS-emulsified copolymerization. The kinetic and particle number data support a micellar-type mechanism for the formation of copolymer particles. Strong affinity between the two monomers and the nonionic surfactant results in significantly high solubilization of the surfactant in the initial monomer phase and its subsequent burial inside the final latex particles.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020101985106
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  • 9
    Electronic Resource
    Electronic Resource
    Copolymerisation azeotropique en emulsion (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 10 (1985), S. 165-184 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: While in solution or bulk radical polymerization, only one azeotropic copolymerization can be observed at the best- if reactivity ratios are both 〉 or 〈 1, on the contrary in emulsion batch copolymerization, many more such azeotropic copolymers can be synthesized. Monomer partitioning between droplet, water and particle phases is at the origin of this behaviour of a particular interest, hence water solubility of the monomers plays a determining role. Experimental works confirm the theoretical predictions derived from an approach, based on partition coefficient and thermodynamics, which allows to compute the optimum monomer/water ratio to be used, in order to get, in a batch process, a copolymer of constant composition up to high conversion. The optimum depends upon reactivity ratios, monomer water solubility, monomer feed composition. Examples are given for acrylonitrile/methyl acrylate copolymerizations. It appears that it is not any more Lecessary that they are both greater or lower than unity; for instance, batch emulsion copolymerizations of acrylonitrile/butyl acrylate (rAN = 0.89; rBuA = 1.2) result in homogeneous copolymers at the optimum monomer/water ratio, in the whole range of monomer feed. The approach can also be applied to semi-continuous process to select the best experimental conditions to “tailor” the copolymer.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020101985114
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  • 10
    Electronic Resource
    Electronic Resource
    Some thermodynamic aspects in emulsion copolymerization (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 10 (1985), S. 235-264 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Emulsion polymerization proceeds in a heterogeneous medium; in copolymerization, due to discrepancy in water solubility and interactions with the resulting copolymers, monomers are partitioned in a complex way between droplet, water and particle phases. As monomer swollen polymer particles are the main loci of polymerization, it is of great interest to know the monomer feed within the particle phase to understand the behaviour of this copolymerization whatever may be the process and the experimental conditions. Two approaches are examined in this lecture to investigate emulsion copolymer and colloid properties of the latexes. A first, simple one is based on experimental partition coefficients and a second one is based on more theoretical thermodynamic considerations (volume fractions, interaction χ parameters …). The latter gives a more general insight of emulsion processes and allows to investigate influence of many parameters like monomer-monomer, monomer-polymer, monomer-emulsifier interactions, interfacial tension, particle size, surface charge density… Computer programs are derived which give predictions in rather good agreement with experiments. The thermodynamic approach allows to study crosslinking effect as well as competition between polymerization rate and monomer diffusion rate if some control by diffusion does occur. Owing to these computer programs it becomes possible to correlate many experimental parameters. Most of experimental date are relative to styrene-acrylonitrile copolymerization.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020101985118
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