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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 11 (1978), S. 514-519 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The use of the polymers tagged with heavy atoms in random positions along the chains (randomly tagged polymers) in small-angle X-ray scattering is proposed as a new method for measuring the chain conformations in concentrated solutions and in bulk polymers. The experimentally determined excess scattering from the tagged chains dispersed in the system is shown to be proportional to the scattering function of the hypothetical chains that have no tags but have the conformation of the tagged chains when the heavy atoms have sufficiently large scattering power. It has been experimentally verified that the effect of the tags on the chain conformation can be eliminated by the extrapolation of the apparent values, measured for a series of tagged polymers with various tag content, to zero tag content. The radii of gyration of the polystyrene chains (M = 1.1 × 105) in the bulk and in concentrated solutions in a good solvent and a θ-solvent have been determined. The chain dimension in a good solvent (toluene at 25°C) decreases rapidly first and then gradually approaches the unperturbed dimension with increasing polymer concentration. The dimension in a θ-solvent (trans-decalin at 21.2°C) is independent of the polymer concentration. The conformation of the polystyrene chains in the bulk was found to be a Gaussian coil.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 23 (1990), S. 134-135 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Bhatia & Thornton [Phys. Rev. B. (1970), 2, 3004–3012] have derived the formula that relates the scattering intensity of a binary system to the Fourier transform of the local number density and concentration. For the intensity at the limit of zero scattering angle, the same formula can be derived by a much simpler process.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 21 (1988), S. 330-339 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A new multipurpose X-ray small-angle scattering camera system consisting of a rotating-anode X-ray generator, a double-focusing collimator and a two-dimensional position-sensitive detector has been developed at the High-Intensity X-ray Laboratory of Kyoto University. The overall camera length is 6 m, and the sample-to-detector distance can be varied in 0.5 m increments up to 3 m to cover scattering angles ranging from 0.001 to 0.18 rad. The collimator consists of a pair of crossed-plane total-reflection mirrors of 40 cm in length. The mirrors, which are mechanically bent to form cylindrical surfaces, provide point collimation free of collimation error. General-purpose sample holders equipped with a programmable temperature controller are provided for both transmission and scattering measurements; the temperature is maintained within ± 0.1 K in the range of 223–573 K. A cryostat for measurements down to 20 K, a dynamic sample deformation apparatus, and a temperature-jump equipment are also available. The multi-wire delay-line position-sensitive proportional counter has an active area of 128 × 128 mm with a spatial resolution of 0.5 × 1.0 mm. The data acquisition is controlled by a real-time front-end processor through a CAMAC interface. The data are recorded in a dual-port histogramming memory of 32 bit × 1 Mwords, which enables direct access to the data from the main computer for real-time monitoring and analysis. The performance of the camera is demonstrated with some selected examples: diffraction patterns from carp lateral line nerve myelin and chicken-tendon collagen fibrils, a Guinier plot of the scattering from polystyrene in dilute solution, and time-resolved measurements of polypropylene during the annealing process.
    Type of Medium: Electronic Resource
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