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  • 1
    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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  • 2
    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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  • 3
    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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  • 4
    Electronic Resource
    Electronic Resource
    Rheo-optical studies of high polymers. XVIII. Significance of the vertical shift in the time-temperature superposition of rheo-optical and viscoelastic properties (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1211-1225 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: To determine the true reason for the increase in birefringence and the decrease in relaxation modulus for high-density polyethylene with rising temperature, changes in crystalline structure as well as in thermal, viscoelastic, and rheo-optical properties with temperature were measured, by several techniques, including DSC, DLI, infrared dichroism, x-ray diffraction, and NMR. The values for degree of crystallinity obtained from the DSC fusion curve, density, and infrared absorbances coincide very well and show almost no divergence till about 80°C. The optical vertical shift factor pT can be related to the ratio of the orientation function for the crystal c axis at an arbitrary temperature to that at the references temperature, fε/fε0. The mechanical vertical shift factor bT, on the other hand, is associated with the temperature dependence of the mobile fraction, as determined by NMR measurements, but not with variations in degree of crystallinity.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080715
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  • 5
    Electronic Resource
    Electronic Resource
    Rheo-optical studies of high polymers. XVII. Time-temperature superposition of time-dependent birefringence for high-density polyethylene (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1195-1209 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The strain-optical coefficient and relaxation modulus were simultaneously measured for high-density polyethylene at various temperatures ranging from 12 to 100°C. Not only horizontal but also vertical shifts were necessary to obtain smooth master curves by the application of time-temperature superposition. However, the relaxation modulus decreases with rising temperature while the strain-optical coefficient increases. This behavior indicates that the variation of the relaxation modulus and the strain-optical coefficient with time can not be explained by a decrease in crystallinity with rising temperature since a decrease in crystallinity usually causes a decrease in the strain-optical coefficient with time can not be explained by a decrease in crystallinity with rising temperature since a decrease in crystallinity usually causes a decrease in the strain-optical coefficient. It was emphasized that another explanation should be sought for the vertical shift in the time-temperature superposition of the time-dependence curves of the relaxation modulus and the strain-optical coefficient at various temperatures. The master curve of the strain-optical coefficient at various temperatures. The master curve of the strain-optical coefficient or the optical distribution function of relaxation times determined from it serve to distinguish the type and thermal history of the polyethylene.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080714
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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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