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We treat here of the question of absorbing boundary conditionsfor nonlinear diffusion equations. We use the conditions designedfor the linear equation, we prove them to be well posed forthe nonlinear problem, and through numerical experiments thatthey are well suited for reactiondiffusion equations. 相似文献
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C. A. Peridier J. L. Matthews M. J. Leitch H. Jeremie M. Irshad B. L. Roberts 《Zeitschrift für Physik A Hadrons and Nuclei》1983,310(4):317-328
The cross section for the3He(γ, 2p) reaction has been measured in a complete kinematics experiment in the energy rangeE γ=80–170 MeV, forθ P1=θ P2=90°. This configuration was selected in order to investigate the role of proton-proton final state interactions in the three-body breakup process. The measured proton spectra are seen to be consistent with a prediction using the Watson-Migdal formalism. The magnitude of the observed cross section clearly indicates an enhancement over phase space, presumably due to the strong proton-proton interaction in the final state. The experimental results agree, within their limited statistical accuracy, with a theoretical calculation which includes this effect. 相似文献
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L. A. Hamel L. Lessard H. Jeremie J. Chauvin 《Zeitschrift für Physik A Hadrons and Nuclei》1985,321(3):439-441
The beta decay rate of the16N(0?; 120keV) →16O(0+, G.S.) transition has been remeasured. Our result (Λ β =0.48±0.024 s?1) is in excellent agreement with a previous measurement but strongly disagrees with another experimental value. The two agreeing results provide an experimental verification of the importance of meson exchange currents in 0+-0? weak transitions. A value ofg p/g A~11–12 can be inferred from the correspondingΛ μ rate. 相似文献
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A. Champagne G. Beaudoin L. A. Hamel H. Jeremie L. Lessard 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(4):377-385
We have measured the beta spectrum of the 0?(120 keV,t 1/2=5.25 μs) state of16N. The response function of our detector has been measured, parameterized and then fitted to known spectral shapes taken under conditions close to those in the actual experiment. Using this response function and subtracting a 56 μs half-life background due to neutron capture in the detector, the measured 0? spectrum compares well with the allowed shape for the 0?→0+ spectrum plus a small contribution from the allowed 0?→1? transition. 相似文献
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Flavonols are naturally occurring dyes that can be extracted from plants. Because of their antioxidant properties, they are thought to have health benefits. In this study, the photochemical degradation properties of selected flavonols were investigated. Dilute solutions of dyes were exposed to light from a broadband visible light source, and the rate of photodegradation was determined by measuring the decrease in fluorescence of the dyes with respect to time. At pH 9.24, the first-order rate constants for 10?µg?mL?1 solutions of myricetin, quercetin, kaempferol, and morin were 0.468, 0.162, 0.108, and 0.126?s?1, respectively. Interestingly, the stability of these historical dyes was also found to be greatly affected by pH. Awareness of the photochemical properties and stability of flavonol dyes is very important for capillary electrophoresis (CE) separations. Photodegradation of the flavonol dyes under the alkaline conditions (pH 9.2) used in CE can have a profound effect on the reproducibility of repeated separations. Even a modest decrease in pH (pH 8.5) greatly improved the stability of these dyes and enabled the successful separation of these flavonol dyes with minimal degradation over time. 相似文献
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The high temperature superconductors of the system Bi-Pb-Sr-Ca-Cu-O show promising properties and large scale applications can be considered. The (Bi,Pb)2Sr2Ca2Cu3O10+ (Bi,Pb(2223)) phase is attractive because of its high superconducting temperature (110 K) and high current transport capabilities.Simultaneous DTA/TG has proved an excellent tool for synthesizing, characterizing these high temperature superconductors, confirming phase diagrams and finding the optimal annealing temperature for Bi,Pb(2223)/Ag tapes in order to obtain high critical current densities around 30 kA cm–2 at 77 K and 0T. The identification of the main DTA peaks of measurement of different phase mixtures made it possible to observe the formation of an intermediate phase Bi,Pb(2212) during the formation of Bi,Pb(2223). 相似文献
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