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91.
We consider the exterior Neumann problem of the Laplacian with boundary condition on a prolate spheroid. We propose to use
spherical radial basis functions in the solution of the boundary integral equation arising from the Dirichlet–to–Neumann map.
Our approach is particularly suitable for handling of scattered data, e.g. satellite data. We also propose a preconditioning
technique based on domain decomposition method to deal with ill-conditioned matrices arising from the approximation problem. 相似文献
92.
93.
Tran Van Hung 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):103-106
The neutron temperature is a characteristic parameter in irradiation channels of reactor. For nuclides which have resonances
in the thermal neutron energy range, their Westcott g-factors are different from unity. The values of g-factors and cross-sections
of (n, γ) reaction of these nuclides are temperature dependence. The standard energy for tabulation of thermal neutron cross-section
(σ0) is that of room temperature (293.59 K or 20.43 °C), corresponding to a neutron energy 0.0253 eV or to a neutron velocity
of 2200 m/s. However, in the irradiation channels of reactor, the temperature is not exact at 20.43 °C. Thus, the temperature
at the irradiation position must be known to convert σ0 to σ(T). A method for determination of the neutron temperature in irradiation channels of Dalat reactor is presented by fitting
the thermal neutron spectrum obtained from the calculation using MCNP code. 相似文献
94.
S. M. Arakelian A. V. Osipov I. O. Skryabin Tran Dinh Phong Nguyen Tran Thuath 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(12):1416-1419
The current-voltage relationships of deposited structures are measured for cluster structures consisting of nanoparticles of lead telluride. Variation in the value of the tunnel current is shown. Optimum conditions for the possible emergence of quantum-hopping conductivity due to carrier tunneling (the characteristic sizes of the nanoclusters and the distances between them) are determined. 相似文献
95.
T. A. Nguyen H. T. Dung 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(1):173-177
Using the Born expansion of the Green tensor, we consider the
spontaneous decay rate of an excited atom placed in the vicinity of
a rectangular plate. We discuss the limitations of the commonly used
simplifying assumption that the plate extends to infinity in the lateral
directions and examine the effects of the atomic dipole moment
orientation, atomic position, and plate boundary and thickness on the atomic
decay rate. In particular, it is shown that
due to the plate finite size, the spontaneous decay may be inhibited
even when the atom is situated very close to the surface, and that
in the boundary region, the
spontaneous decay rate can be strongly modified. 相似文献
96.
Our research involves the development of new cationic materials for anion-based applications. We report the solvothermal synthesis and characterization of Pb(3)F(5)NO(3), a new layered lead fluoride material that, unlike the majority of layered and open-framework materials, is cationic in charge. The structure consists of polyhedral lead centers connected by doubly and triply bridging fluoride groups. We quantitatively exchanged the interlamellar nitrate groups of Pb(3)F(5)NO(3) for dichromate, under ambient aqueous conditions. Nuclear magnetic resonance and UV-vis spectroscopy show the reaction proceeds to 61.0% completion in several days. The material is also stable to 450 degrees C, which is vastly superior to organic resins that are still the standard for anion-exchange. The presence of extraframework anions also opens up other potentially unique anion-based properties, such as new catalytic reactions, anion intercalation, or growth of anionic clusters within the void spaces of the cationic material. 相似文献
97.
Tezuka Y Stampoulis P Banskota AH Awale S Tran KQ Saiki I Kadota S 《Chemical & pharmaceutical bulletin》2000,48(11):1711-1719
From the MeOH extract of the aerial part of Vietnamese Orthosiphon stamineus, five new isopimarane-type diterpenes [orthosiphols F-J (1-5)] and two new diterpenes [staminols A (6) and B (7)] with a novel carbon-framework, to which we proposed the name "staminane", and three new highly-oxygenated staminane-type diterpenes [staminolactones A (8) and B (9) and norstaminol A (10)1 were isolated. Moreover, staminolactone A (8) is 8,14-secostaminane-type and staminolactone B (9) is 13,14-secostaminane-type, while norstaminol A (10) is 14-norstaminen-type. Together with these new diterpenes, sixteen known compounds were also isolated and identified to be: 7,3',4'-tri-O-methylluteolin (11), eupatorin (12), sinensetin (13), 5-hydroxy-6,7,3',4'-tetramethoxyflavone (14), salvigenin (15), ladanein (16), tetramethylscutellarein (17), 6-hydroxy-5,7,4'-trimethoxyflavone (18), vomifoliol (19), aurantiamide acetate (20), rosmarinic acid (21), caffeic acid (22), oleanolic acid (23), ursolic acid (24), betulinic acid (25), and beta-sitosterol (26). All the isolated compounds were tested for their cytotoxicity towards highly liver metastatic murine colon 26-L5 carcinoma cells, and the new diterpenes, except for 4, and flavonoids (11, 12, 16, 18) showed cytotoxicity with an ED50 value between 10 and 90 microg/ml. 相似文献
98.
Streubel R Schiemann U Jones PG Tran Huy NH Mathey F 《Angewandte Chemie (International ed. in English)》2000,39(20):3686-3688
99.
100.