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  • 1
    Electronic Resource
    Electronic Resource
    Bending properties of compression molded three-layer long fiber polypropylene composites (1994)
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 15 (1994), S. 327-333 
    Details
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The results of studies on bending properties of three-layer long fiber polypropylene composites are presented. Thirteen samples with glass fibers of various lengths (i.e., 13, 25, 50 mm and continuous fiber length) in the laminates were prepared by stamping. Bending properties of shorter lengths exhibited a large scatter. On substitution of the middle layer with a continuous glass fiber the scatter was reduced. These results have been explained on the basis of flow models and X-ray shadowgraphs, which showed that both slippage flow and orientation of the glass fiber during stamping are the major phenomena responsible for the scatter.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pc.750150503
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  • 2
    Electronic Resource
    Electronic Resource
    Flow behavior of stampable sheet with a rib part (1994)
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 15 (1994), S. 393-400 
    Details
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The effect of die design on the flow characteristics of compression molded three-layer long glass fiber reinforced polypropylene composite, known as “stampable sheet,” was investigated. The flow behavior of each layer was observed by optical and soft X-ray photographs. The fiber flow length into the rib part was measured by an image processing system. The results showed that during compression resin exudation occurred and that this depended on the die's rib width. Thus, the larger the rib width, the lower the amount of resin exuded. Resin exudation was found to occur earlier in a die with zero fillet radius. The fiber flow length into the rib part was enhanced by using a die with a large fillet radius. The results were confirmed by a short-shot molding process. In this process, the stamping operation was stopped short of making a complete part.A finite element method was used to study the flow process. The results agree with the experimental results confirmed by short-shot molding.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pc.750150603
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  • 3
    Electronic Resource
    Electronic Resource
    Statistical mechanical theory for liquid-crystalline polymer solutions (1994)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 45 (1994), S. 399-412 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A statistical mechanical theory is presented for liquid-crystalline polymer solutions, where the liquid-crystalline polymer is regarded as a wormlike spherocylinder interacting by the hard-core repulsion and a soft (attractive or electrostatic) interaction with other spherocylinders. The theory is based on the following two assumptions: (1) the intramolecular excluded volume effect is not effective and (2) the interaction between pair of spherocylinders can be treated by the “single contact approximation”. These assumptions are relevant to a polymer with a stiff backbone and not very long contour length. The theory is used to predict thermodynamic and spatial properties of isotropic solutions and also isotropic-liquid crystal phase equilibrium behavior. The predicted solution properties and phase behavior are favorably compared with experimental results for some selected stiff-chain liquid-crystalline polymers.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1994.010450601
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  • 4
    Electronic Resource
    Electronic Resource
    Dynamics of stiff-chain polymers in multicomponent solutions: Modification of the hole theory (1995)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 46 (1995), S. 445-452 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The previous theory of the global motion dynamics of stiff-chain polymers in multicomponent systems has been modified by a refined treatment of the jamming effect on the longitudinal diffusion of polymer chains along their end-to-end axis to derive a new equation for zero-shear viscosity, which depends on the longitudinal diffusion coefficients through the lifetimes of entanglements between similar as well as dissimilar polymers. Along with this theoretical study, experimental data forzero-shearviscosity of quasi-ternary solutions containing two stiff-chain polymers with different lengths were obtained. They were well described by the viscosity equation obtained, with only the similarity ratio(s) inherent to the respective polymer-solvent system(s) as adjustable parameter(s).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1995.010460607
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  • 5
    Electronic Resource
    Electronic Resource
    Radical polymerization of 3-cyano-3-ethoxycarbonylpropyl vinyl ether via addition-abstraction mechanism (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2839-2847 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1988.080261020
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  • 6
    Electronic Resource
    Electronic Resource
    Structure of guanylyl-3′,5′-cytidine monophosphate. II. Description of the molecular and crystal structure of the calcium derivative in space group P21 (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 227-236 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structural features of calcium guanosine-3′,5′-cytidine monophosphate (GpC) have been elucidated by X-ray diffraction analysis. The molecule was crystallized in space group P21 with cell constants of a = 21.224 Å, b = 34.207 Å, c = 9.327 Å, and β = 90.527°, Z = 8. The hydration of the crystal is 21% by weight with 72 water molecules in the unit cell. The four GpC molecules in the asymmetric unit occur as two Watson-Crick hydrogen-bonded dimers related by a pseudo-C face centering. Each dimer consists of two independent GpC molecules whose bases are hydrogen bonded to each other in the traditional Watson-Crick fashion. Each dimer possesses a pseudo twofold axis broken by a calcium ion and associated solvent.The four molecules are conformationally similar to helical RNA, but are not identical to it or to each other. Instead, values of conformational angles reflect the intrinsic flexibility of the molecule within the range of basic helical conformations. All eight bases are anti, sugars are all C3′-endo, and the C4′-C5′ bond rotations are gauche-gauche. The R factor is 12.6% for 2918 observed reflections at 1.2-Å resolution.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140116
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  • 7
    Electronic Resource
    Electronic Resource
    Structure of guanosine-3′,5′-cytidine monophosphate. I. Semi-empirical potential energy calculations and model-building (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 2731-2750 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformation and packing scheme for guanosine-3′, 5′-cytidine monophosphate, GpC, were computed by minimizing the classical potential energy. The lowest energy conformation of the isolated molecule had dihedral angles in the range of helical RNA's and the sugar pucker was C3′ endo. This was used as the starting conformation in a packing search over orientation space, the dihedral angles being flexible in this step also. The packing search was restricted by constraints from our x-ray data, namely, (1) the dimensions of the monoclinic unit cell and its pseudo-C2 symmetry (the real space group is P21), (2) the location of the phosphorous atom, and (3) the orientation of the bases. In addition, a geometric function was devised to impose Watson-Crick base pairing. Thus, a trial structure could be sought without explicit inclusion of intermolecular potentials. An interactive computer graphics system was used for visualizing the calculated structures.The packing searches yielded two lowest energy schemes in which the molecules had the same conformation (similar to double-helical RNA) but different orientations within the unit cell. One of these was refined by standard x-ray methods to a discrepancy index of 14.4% in the C2 pseudocell. This served as the starting structure for the subsequent refinement in the real P21 cell.5
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360121208
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  • 8
    Electronic Resource
    Electronic Resource
    Conversion of Auger sensitivities at one primary excitation energy to those at anotherPaper presented at the Quantitative Surface Analysis (QSA-5) Conference, London, 15-18 November 1988. (1989)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 14 (1989), S. 787-793 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: In Auger electron spectroscopy, the relative sensitivities of elements, which are widely used in quantitative analysis, are primarily obtained by measurement. Nevertheless, it is very tedious to collect all relative elemental sensitivity factors for different primary electron beam energies. In view of this, we have examined methods of deriving the relative sensitivity factor for an arbitrary electron beam energy from one experimental value determined at a set energy. For this calculation, we have to consider the contributions of the ionization cross-section and the electron backscattering factor. Several formulas for the ionization cross-section and the backscattering correction factor have been reported. We have performed experiments to examine their correction accuracy. It was found that when Gryziński's formula is used as the ionization cross-section and Love-Scott's formula as the backscattering correction factor, the difference between calculated sensitivity values and measured values was found to be 〈15% for excitation energies of 〈20 keV.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740141116
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