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[en] A method was developed for calculating the molecular weight distribution of a polymer melt from its rheology, specifically dynamic or relaxation moduli data. The molecular weight range covered by the solution is specified by the source data or the entanglement molecular weight, and the blending rule consistent with double reptation was used. The solutions for both the discrete relaxation spectrum and final molecular weight distribution were obtained by Tikhonov regularization with the molecular weight distribution solution being particularly sensitive to the value of the regularization parameter λR used in the calculations. Here, λR was varied and patterns developed between the most appropriate values for an acceptable solution and the polydispersity of the corresponding samples. For relatively low λR values, the algorithm was precise enough to resolve individual components in nearly monodisperse, binary blend, and multimodal systems with as many as 13 components. Results for commercial materials of varying polydispersity generally agreed with the molecular weight distributions from chromatography with slightly higher λR values, particularly the location of peak molecular weights. Commercial polyolefins, which required still higher λR values, gave consistently poorer results due to restricted molecular weight ranges allowed by the source data
[en] The design thermoplastic-film recording camera and its performance for holography of extended objects are reported. Special corona geometry and accurate control of development heat by constant current heating and high resolution measurement of the develop temperature make easy recording of reproducible, large aperture holograms possible. The experimental results give the transfer characteristics, the diffraction efficiency characteristics and the spatial frequency response. (orig.)
[en] The dose dependences of break stress of polymer materials and its specific lengthening at breakage of polymer materials were calculated within frames of model of free jointed chain with using of cascade-probably method. According of experimental data one can judge about polymer radiation stability and give recommendation on its use at electrotechnical machines and apparatus contraction using under ionization radiation
[en] A presensitized article having a radiation-sensitive layer comprising an adduct of an amorphous sulfopolyester and a diazonium resin is described which does not exhibit blocking on being stored in stacks for prolonged periods of time. The article can be exposed to radiation and developed via aqueous solvents to provide a lithographic plate that provides clean, scum-free copies, and that can be stored in a high humidity atmosphere without failure
[en] We report the dependence of the ortho-positronium (o-Ps) lifetime τ3 and intensity I3 on the thermodynamic history of a number of amorphous homopolymer and copolymer glasses that were pressure-densified at pressures up to 200 MPa. Small macroscopic volume changes up to 1.85% yield large microscopic volume changes in the pressure-densified glasses, i.e., τ3 decreases by a maximum of 9%, while I3 remains constant, and the Simha-Somcynsky free-volume fraction decreases by a maximum of 31% and correlates with the free-volume size Vτ3.
[en] This study was performed to localize the high frequency ultrasonic transducers using polyvinylidene fluoride (PVDF) and polyvinylidene fluoride trifluorethylene (copolymer). The characteristics of fabricated high frequency transducers such as beam diameter, frequency spectrum and pressure level of the first echo signal from the specimen in the water were analyzed and compared. As test specimens, the steel balls with 0.5 mm and 1.5 mm diameter and steel block with 30 mm thick were used. The high frequency detection field of a transducer was affected by increasing the length of cable between high frequency transducer and ultrasonic pulser/receiver. As the size of a specimen increased, the high frequency detection field decreased and the amplitude of a reflection signal increased. The pressure level of copolymer tranduser was found to be higher than that of PVDF transducer but the high frequency detection field of PVDF was wider than that of copolymer.