منابع مشابه
Directed polymers in high dimensions.
We study directed polymers subject to a quenched random potential in d transversal dimensions. This system is closely related to the Kardar–Parisi– Zhang equation of nonlinear stochastic growth. By a careful analysis of the perturbation theory we show that physical quantities develop singular behavior for d → 4. For example, the universal finite size amplitude of the free energy at the rougheni...
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Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition temperature (Tg) and photodefinable properties. The polymers tested are polysulfone (PS) and polycarbonate (PC). The electro-optic chromophore, tricyanovinylidenediphenylaminobenzene (TCVDPA),which was reported to have a highest photochemical stability [1] has been employed in the...
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Renewably sourced, also commonly referred as biobased, materials are an integral part of DuPont’s commitment to sustainable growth. DuPont is a market leader in high performance renewably sourced polymers for engineering applications. These include products based on polyamide, polyester and thermoplastic elastomers and contain between 20 to 100 percent renewable carbon by weight. By tapping inn...
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Work on thermal ~egradation of poly mers has prev iously been carried out aL lempC'mt ures up to about 500 G. In the present work the range has been extend cd to 850 0 C. Polystyrene was pyrolyzed in a vacuum and also in helium at atmos pheric pressure at 3620 and at 850 0 C. Analysis of t he volatile products indicates that higher temperatures a nd hi~her. pressures cause a greater fragmen tat...
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The infrared spectrum of polyethylene has been obtained between about 3000 cm-1 and 70 em-I, polarization measurements on oriented specimens having been obtained to about 350 em-l. Assignments of the fundamentals are made with the help of a group theory analysis. The assignment of the controversial CH. wagging mode is discussed in detail and especially in terms of new evidence from the spectra ...
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ژورنال
عنوان ژورنال: Nature
سال: 1958
ISSN: 0028-0836,1476-4687
DOI: 10.1038/182772a0