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161.
M. Yamamoto K. Shiraishi I. P. Los I. Y. Kamarikov M. G. Buzinny 《Journal of Radioanalytical and Nuclear Chemistry》1995,201(6):459-468
As a preliminary survey to establish intake of -emitting nuclides, in particular239,240Pu, from a daily diet for inhabitants living near the Chernobyl reactor site, some kinds of food samples including total diet samples were collected in the Chernobyl (Ukraine) area and in the Ibaraki prefecture (Japan). Plutonium-239 and 240 were determined together with naturally occurring -emitters226Ra and U isotopes (234U,235U and238U) by -spectrometry after chemical separation. In most of the samples studied,239,240Pu was less than the detectable amount, but in some mushrooms from the Ukraine it was found to be 41.6 mBq kg–1 (wet mass) with a high activity ratio(0.58±0.08) of238Pu/239,240Pu, indicating that nearly 100% of the239,240Pu was attributable to the accident. Concentrations of226Ra and238U varied largely, depending on the samples. The measured activity ratios of235U/238U for some samples showed the isotopic composition of natural uranium. 相似文献
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166.
In this paper, an optimal control problem for the stationary Navier-Stokes equations in the presence of state constraints is investigated. Existence of optimal solutions is proved and first order necessary conditions are derived. The regularity of the adjoint state and the state constraint multiplier is also studied. Lipschitz stability of the optimal control, state and adjoint variables with respect to perturbations is proved and a second order sufficient optimality condition for the case of pointwise state constraints is stated. 相似文献
167.
K. Shiraishi Y. Muramatsu I. P. Los V. N. Korzun N. Y. Tsigankov P. V. Zamostyan 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(1):199-202
Total diet samples for Ukrainians and Japanese were collected by duplicate portion studies in relation to the Chernobyl accident.
Stable iodine and bromine in the diet samples were determined by using ICP-MS after chemical separation. Daily intakes of
iodine for Ukrainians and Japanese were found to be 110±104 and 1770±1610 μg per person per day, respectively. Daily intakes
of Br were as follows: Ukrainians 3.47±2.12 mg; Japanese 11.4±2.4 mg. Daily iodine intake in Ukrainians was lower than the
recommended dietary allowance (150 μg) and showed the relationship of high prevalence of goiter in this area. 相似文献
168.
V. Luis De Los Santos Dongwook Lee F. Lizbet Leon Seiichi Suzuki Thanos Mitrelias Crispin H.W. Barnes 《Surface science》2009,603(19):2978-2985
A crystallization and surface evolution study of Au thin film on SiO2 substrates following annealing at different temperatures above the eutectic point of the Au/Si system are reported. Samples were prepared by conventional evaporation of gold in a high vacuum (10−7 mbar) environment on substrates at room temperature. Thermal treatments were performed by both furnace and flame annealing techniques. Au thin films can be crystallized on SiO2 substrates by both furnace and flame annealing. Annealing arranges the Au crystallites in the (1 1 1) plane direction and changes the morphology of the surface. Both, slow and rapid annealing result in a good background in the XRD spectra and hence clean and complete crystallization which depends more on the temperature than on the time of annealing. The epitaxial temperature for the Au/SiO2 system decreases in the range of 350-400 °C. Furnace and flame annealing also form crystallized gold islands over the Au/SiO2 surface. Relaxation at high temperatures of the strained Au layer, obtained after deposition, should be responsible for the initial stages of clusters formation. Gold nucleation sites may be formed at disordered points on the surface and they become islands when the temperature and time of annealing are increased. The growth rate of crystallites is highest around 360 °C. Above this temperature, the layer melts and gold diffuses from the substrate to the nucleation sites to increase the distance between islands and modify their shapes. Well above the eutectic temperature, the relaxed islands have hexagonally shaped borders. The mean crystallite diameters grow up to a maximum mean size of around 90 nm. The free activation energy for grain boundary migration above 360 °C is 0.2 eV. Therefore the type of the silicon substrate changes the mechanism of diffusion and growth of crystallites during annealing of the Au/Si system. Epitaxial Au(1 1 1) layers without formation of islands can be prepared by furnace annealing in the range of 300-310 °C and by flame annealing of a few seconds and up to 0.5 min. 相似文献
169.
I.?A.?Santos R.?G.?Mendes J.?A.?Eiras J.?de?Los?S.?Guerra E.?B.?Araújo 《Applied Physics A: Materials Science & Processing》2009,95(3):757-760
The dielectric properties of Sr0.75Ba0.25Nb2O6 relaxor ferroelectric thin films were carefully analyzed. In contrast to bulk samples which present three distinct dielectric
relaxation phenomena Sr0.75Ba0.25Nb2O6 thin films present only two of them. The suppression of the third anomaly can be mainly attributed to the narrow grain size
distribution of nanograins and weak tensile strains imposed to the film from the substrate. The whole set of results point
to the interpretation of a dielectric response characteristic of mesoscopic structure, which is composed of clusters and nanodomains. 相似文献
170.
David GuerinDominique Lorcy Roger CarlierSzymon Los Lidia Piekara-Sady 《Journal of solid state chemistry》2002,168(2):590-596
Various extended π-donor molecules incorporating an azino spacer between two heterocyclic moieties, either dithiole or thiazole rings, are described. As evidenced by cyclic voltammetric studies, the donor ability of these derivatives can be modulated depending on the nature of the two heterocycles. Three similar crystalline complexes were obtained with TCNQ and the donors 4, 7 and 8. Crystal structures and magnetic susceptibility data of these complexes are presented and the degree of charge transfer within these complexes has been correlated with the redox properties. 相似文献