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  • 1
    Electronic Resource
    Electronic Resource
    Elasticity of poly(diacetylene) gels: measurements by electric field coupling (1986)
    s.l. : American Chemical Society
    Macromolecules 19 (1986), S. 676-681 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00157a033
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  • 2
    Electronic Resource
    Electronic Resource
    Conformation of polydiacetylene macromolecules in solution: Field induced birefringence and rotational diffusion constant (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 516-521 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Application of an external electric field induces birefringence in a solution of polydiacetylene (poly-4BCMU) in toluene due to orientation of the macromolecules. The field induced orientation in the red phase indicates an anisotropic polarizibility tensor characteristic of a rod-like conformation. The birefringence due to the polymer in its coil conformation (yellow phase) is extremely weak. The transient response of the anisotropic light scattering was studied in the red phase after switching the electric field on or off. We find a free rotational relaxation time of ∼0.1 s, consistent with the rotational diffusion constant expected for rod-like polydiacetylene macromolecules. These results rule out the large aggregate interpretation proposed to explain the color change transition. The field induced birefringence data independently demonstrate the existence of the rod-coil conformational transition for polydiacetylene 4BCMU macromolecules in solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.448773
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  • 3
    Electronic Resource
    Electronic Resource
    Spectroscopic and light scattering studies of the conformational (rod-to-coil) transition of poly(diacetylene) in solution (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 522-530 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A rod-to-coil conformational transition has been demonstrated for polydiacetylene, 4-butoxy-carbonyl-methylurethane (4BCMU) in solution. The transition can be induced by changing either the temperature or the quality of the solvent. The light scattering and spectroscopic data as a function of polymer concentration have shown that the transition is a single chain (intramolecular) phenomenon. However, because of the large end-to-end length (L(approximately-equal-to)1.2 μm) of the fully extended polymer, the dilute limit is not reached until concentrations below 10−5 g/cm3. At higher concentrations evidence of cluster growth and aggregation are observed prior to gelation which occurs above a critical concentration c0(approximately-equal-to)5×10−4 g/cm3. This cluster growth occurs as a result of the rod-like conformation of the individual molecules, but it is not the cause of the transition. The large increase in scattering intensity (at fixed polymer concentration) on going from coil to rod follows directly from the change in dielectric constant due to the spectral shift of the π–π* absorption; no significant increase in molecular weight is implied by the data. A theoretical model of the transition has been developed in which the ordered rod-like conformation is the low temperature phase. Conformational kinks (to a coil phase) cost energy through interruption of the π-electron delocalization and through the breaking of H bonds between R groups. Nevertheless, the increase in entropy associated with the many degrees of freedom of the coil-like conformation is sufficient to lead to the observed transition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.448774
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  • 4
    Electronic Resource
    Electronic Resource
    Liquid crystal millimeter wave electronic phase shifter (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 1065-1067 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The birefringence of two common nematic liquid crystals were measured in the millimeter wave range, and were found to be in the range of 0.19–0.22 at room temperature. Using liquid crystal electro- and magneto-optical effects, we present the first experimental data of a novel liquid crystal millimeter wave electronic phase shifter. Our experiments show that liquid crystals could play an important role in future millimeter wave device technologies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108796
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  • 5
    Electronic Resource
    Electronic Resource
    Reply to Comment on "Polydiacetylene macromolecules in solution: Electric field induced birefringence'' (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 1058-1059 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450846
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  • 6
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    The Monarchical Movement in China (1915)
    London : Periodicals Archive Online (PAO)
    The Contemporary Review. 108 (1915:July/Dec.) 643 
    Details
    ISSN: 0010-7565
    Topics: General, Interdisciplinary
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:0274-1915-108-00-000089
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  • 7
    Electronic Resource
    Electronic Resource
    Superconductivity in bulk A15 Nb3Si under pressure (1981)
    Springer
    Journal of low temperature physics 45 (1981), S. 575-580 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have determined the effect of hydrostatic pressureP on the superconducting transition temperatureT c of bulk, A15 Nb3Si. For 0≤P≤20 kbar (2 GPa),T c decrease linearly with increasing pressure at a rate ∂T c/∂P=−2.67×10−5 K/bar. From an estimate of ∂T c/∂P obtained using recent band structure calculations for the density-of-electronic-states change as a function of lattice parameter in Nb3Si, we conclude that the pressure dependence of the electron-phonon interaction primarily determines ∂T c/∂P.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00654500
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  • 8
    Electronic Resource
    Electronic Resource
    Theory of the rod-to-coil transition in polydiacetylene (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 847-852 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A theory is proposed for the rod to coil transition in polydiacetylene 4BCMU and related polymers which is based on the hypothesis that the high-temperature (yellow) phase consists predominantly of the cis structure, while the low-temperature (red) phase is trans. Because the occurrence of a cis-trans interface is energetically costly, the correlation length for either isomer remains long and the transition is sharp, much like the helix-coil transition in the theory of Zimm and Bragg. The transition is driven by the higher entropy of the cis isomer, which is free to coil, unlike the trans or butatriene forms. The theory gives excellent agreement with optical absorption measurements and is consistent with all other experimental data for this system.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220506
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