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951.
S. A. Voitsekhovskii 《Journal of Mathematical Sciences》1991,54(2):751-757
We consider the application of the fictitious region method to solve the first and second boundary-value problems for a second-order quasilinear elliptical equation. Rate of convergence bounds are obtained for two versions of the fictitious region method.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 56, pp. 7–14, 1985 相似文献
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Kikue S. Burnham Robert Roth Faith Zhou Wenya Fan Emma Brouk Mehari Stifanos 《Journal of polymer science. Part A, Polymer chemistry》2006,44(24):6909-6925
In an attempt to develop a low‐k interlayer dielectric, adamantane‐diphenyldiethynyl moiety containing oligomer is prepared. Oligomerization of 1,3,5,7‐tetrakis[3/4‐ethynylphenyl]adamantane ( 4 ) is accomplished by a Glaser–Hay oxidative coupling with 1,3,5‐triethynylbenzene and phenylacetylene end‐capping agent. The CHCl3 soluble oligomer is then thermally treated by step‐curing at 200, 300, 380, and 450 °C for 30 min at each temperature under nitrogen flow to render a shiny void‐free black polymer. TGA analysis indicates that the polymer is stable under nitrogen up to 500 °C with a marginal decomposition up to 800 °C. Solid‐state 13C NMR, Raman scattering, and FTIR are used to characterize the structure of the polymer. The polymer consists of amorphous carbon networks with the adamantane moieties and nanosized graphitic regions (clusters), which are generated from the thermal crosslinking of the diphenyldiethynyl units. It shows a remarkably low linear coefficient of thermal expansion (~25 ppm/°C), presumably due to the presence of the disordered graphitic structure. Its high density (~1.21 g/cm3), refractive index (~1.80 at 632 nm), and Young's modulus (~17.0 GPa) are also consistent with the interpretation. This study reveals important details about the effect of microscopic structure on the macroscopic properties of the highly crosslinked polymer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6909–6925, 2006 相似文献
955.
A theoretical framework is provided for generalizing the inferences drawn from the results of earlier experimental studies of kinetics of crystallization in oriented poly(ethylene terephthalate). The framework is obtained by combining extensions of classical nucleation theories in polymers3,4 and a theory of crystal growth with anisotropic incorporation of segments into growing crystals.15 It is shown that, while a very strong dependence of rate of primary nucleation on orientation does exist, there is a only a much weaker dependence of rate of crystal growth on the orientation of the crystallizing polymer. The theoretical formulation provided here would allow qualitative estimates for comparison with experiments. 相似文献
956.
M. V. Davidovich 《Radiophysics and Quantum Electronics》2006,49(3):210-219
We propose a method which transforms homogeneous integral equations into inhomogeneous ones for problems of diffraction by
semi-infinite structures. New integral equations and the corresponding stationary functionals dependent on the desired scattering
parameters are obtained. The consideration is performed for the open-end diffraction problem of a parallel-plate waveguide
which has a rigorous solution, but the method has sufficient generality to use it for two-dimensional surface integral equations
describing planar and nonplanar structures as well as for an arbitrary structure of waveguide transformer type, the solution
for which can be sought in the finite domain. The method is based on field representation at the infinity as incident and
scattered waves.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 3, pp. 235–245, March 2006. 相似文献
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A method for estimating the systematic uncertainty associated with radon in the SAGE experiment1) aimed at observing the solar-neutrino flux is described. For the gallium target used in this experiment, the systematic uncertainty in the measured neutrino-capture rate of 75 SNU2) is below 0.3 SNU. 相似文献