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  • 1
    Electronic Resource
    Electronic Resource
    Laser irradiance of a homogeneous metal slab (1990)
    Springer
    Czechoslovak journal of physics 40 (1990), S. 576-584 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Numerical calculations of the effect of laser irradiance was performed for three homogeneous slabs. The temperature profile and the temperature of the front surface for three metals, silver, steel, and aluminium was calculated. The formulation of the temperature distribution of the slab was carried out using Fourier series expansions for the case of time dependent laser irradiance. The exact expressions for the thermal penetration depth and the critical time required to initiate melting (i.e. damage) were found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01599781
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The transverse compression of oriented nylon and polyethylene extrudates (1978)
    Springer
    Journal of materials science 13 (1978), S. 1381-1387 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A theoretical treatment is given for the total diametral compression of a transversely isotropic elastic cylinder under compression between parallel rigid plates under conditions of plane strain. Experimental results are presented for the compression of isotropic and oriented cylinders of nylon 6.6 and linear polyethylene (Rigidex). These results confirm that the theoretical treatment is valid to a good degree of approximation. In the case of linear polythylene, where data are presented for ultra-highly oriented extrudates, the results are of some interest with regard to the elastic properties of these unusual materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553190
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The dielectric properties of liquid-crystal random copolyesters of 4-hydroxybenzoic acid and 2-hydroxy 6-naphthoic acid (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1751-1760 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dielectric measurments made from 1 Hz to 10 kHz and from -80 to 150°C on random copolyesters of 4-hydroxybenzoic acid (HBA) and 2-hydroxy 6-naphthoic acid (HNA) reveal three relaxation processes at low frequencies rather than the two seen at audio frequencies. The higher temperature α process is similar to a glass transition, with a high activation energy ∼ 170 kcal/mol, but the two lower temperature processes are identified as local mode processes associated with the HNA and HBA moieties, respectively. It is shown that the observed value of the permittivity above the glass transition is lower than that which would be expected for ester groups rotating freely about the local chain axis, and it is suggested that this may be due to several factors including immobilization of dipoles in the crystalline regions, correlated motion of dipoles, and librational rather than rotational motion.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260814
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Electrical β-relaxation of die-drawn isotactic polypropylene (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 40 (1996), S. 295-298 
    Details
    ISSN: 0959-8103
    Keywords: drawn polypropylene ; relaxation ; phase angle ; impedance ; 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: Measurements of a.c. impedance were carried out in the frequency range 1 Hz to 106 Hz at room temperature on isotropic and die-drawn isotactic polypropylene. It was found that the a.c. impedance decreases with increasing draw ratio in the frequency range 1 Hz to 104 Hz and then becomes independent of draw ratio with increasing frequency. A dramatic drop in the a.c. impedance was observed in the frequency range 104 to 106 Hz, which is associated with a β-relaxation process. The intensity of the β-relaxation peak decreases with increasing draw ratio and nearly disappears for a draw ratio of 16·8. The Cole Cole plots show good semicircles for isotropic and die-drawn samples indicating that a certain polarization mechanism is dominant in polypropylene.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Elastic moduli of liquid crystalline copolymers (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 373-376 
    Details
    ISSN: 0959-8103
    Keywords: aggregate model ; liquid crystals ; compliances ; shear tensile ; elastic moduli ; 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: Dynamic tensile and shear moduli measurements have been carried out on highly oriented thermotropic liquid crystalline copolymers formed by random copolymerization of 2-hydroxy-6-naphthoic acid, terephthalic acid and p-aminophenol. This liquid crystalline copolymer is known as HNATA. Application of the aggregate model of units of structure gives rise to an estimation of the orientation angle θ = 5° and a chain modulus Ec = 230 GPa. The fall in tensile modulus with increasing temperature is related to two factors: a decrease in the intrinsic chain modulus and a reduction in the shear modulus.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330405
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanical and dielectric relaxations in liquid crystalline copolyesters (1990)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 1 (1990), S. 41-47 
    Details
    ISSN: 1042-7147
    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
    Notes: Dynamic mechanical measurements in tension and torsion on oriented tapes and monofilaments of a range of liquid crystalline polyesters have been combined with dielectric measurements to obtain a molecular understanding of the relaxation processes.This paper extends our previous work [1,2,3] on polyesters of hydroxybenzoic acid (HBA) and hydroxynaphthoic acid (HNA) to related polymers containing dihydroxynaphthalene (DHN) and terephthalic acid (TPA) or biphenyl (BP) and TPA in place of the HNA. It confirms the association of the β and γ processes with naphthyl and phenyl moieties but shows that the processes cannot be due simply to the independent motions of single units.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1990.220010107
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    Paper (German National Licenses)
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