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This presented study is to make comparison of cross sections to produce 117Sb and 90Nb via different reactions with particle incident energy up to 70 MeV as a part of systematic studies on particle-induced activations on enriched Sn, Y2O3 and ZrO2 targets, theoretical calculation of production yield, calculation of required thickness of target and suggestion of optimum reaction to produce Antimony-117 and Niobium-90. 相似文献
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Pengtao Li 《Journal of Mathematical Analysis and Applications》2010,369(2):595-609
In this paper, we establish a link between Leray mollified solutions of the three-dimensional generalized Navier-Stokes equations and mild solutions for initial data in the adherence of the test functions for the norm of . This result applies to the usual incompressible Navier-Stokes equations. 相似文献
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Mingjin Wang 《Journal of Mathematical Analysis and Applications》2008,341(2):1487-1494
In this paper, we use the Andrews-Askey integral and the q-Chu-Vandermonde formula to derive a more general integral formula. Applications of the new integral formula are also given, which include to derive the q-Pfaff-Saalschütz formula and the terminating Sears's transformation formula. 相似文献
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The self-diffusion coefficient of water in Nafion-117 membrane in different cationic forms was measured by the transient radiotracer method, which is based on an analytical solution of Fick's second law. The self-diffusion coefficient of water in the membrane was obtained from the analysis of time-dependent isotopic-exchange rates of tritium tagged water between sample of Nafion-117 membrane and equilibrating water. This transient method does not require the knowledge of partition coefficient of water, which is an essential parameter in the radiotracer permeation method. In present work, self-diffusion coefficients of water in the Nafion-117 membrane with H+, Li+, Ag+, Na+, K+, Rb+ and Cs+ monovalent counterions were obtained. The values of logarithm of self-diffusion coefficients were found to vary linearly as a function of polymer volume fraction except for membrane sample with H+ counterions. The self-diffusion coefficient of water in Nafion-117 membrane with H+ counterions was significantly different from the trend observed in the variation of self-diffusion coefficient of water as a function of polymer volume fraction in the membrane with other monovalent counterions. This observation seems to suggest that the physical structure of Nafion-117 membrane in H+ form may be quite different from the Nafion-117 membrane with other monovalent counterions. The high self-diffusion coefficient of water (1.67 × 10−6 cm2/s) in Nafion-117 membrane with Cs+ counterions indicates that the ionic clusters in Nafion-117 membrane are well connected even at low water content (8.2 wt.%) in the membrane. 相似文献
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Peter G. Sutton Christopher F. Harrington Ben Fairman E. Hywel Evans Les Ebdon Tim Catterick 《应用有机金属化学》2000,14(11):691-700
Synthetic methods for the small‐scale laboratory preparation of isotopically enriched dibutyltin dichloride, dibutyltin di‐iodide, tributyltin chloride, tributyltin iodide, diphenyltin dichloride, triphenyltin chloride and triphenyltin iodide have been successfully established. Organotin iodides were prepared from redistribution reactions between tin(IV) iodide and the corresponding tetraorganotin, with the exception of dibutyltin di‐iodide, which was prepared directly from the reaction between tin metal and iodobutane. The development of novel procedures for the dealkylation/dearylation of tetraorganotins by acid hydrolysis produced superior yields of tributyltin chloride and diphenyltin dichloride in comparison with redistribution reactions. Organotin iodide redistribution reaction products were converted to their chloride analogues via the fluoride salts using an aqueous ethanolic solution of potassium fluoride. The insolubility of organotin fluoride salts was exploited to isolate and purify the isotopically enriched compounds, and to prevent losses during the purification procedure. The nuclear magnetic resonance (NMR) spectroscopic study of ‘natural abundance’ and isotopically enriched organotin compounds gave proton (1H) and carbon‐13 (13C) spectra for butyltins, Bu4−nSnXn, and phenyltins, Ph4−nSnXn (X = I, Cl), allowing the assignment of 1H and 13C chemical shifts, and 119Sn–13C and 117Sn–13C coupling constants. The 13C NMR spectroscopic analysis of 117Sn‐enriched organotin compounds has allowed the assignment of certain resonances and tin–carbon coupling constants which were previously unobservable. The spectral patterns show that Δ(1H) and Δ(13C) values are sensitive to structural changes, and that 13C shielding decreases with an increase in the electronegativity of the substituent. The tin–carbon coupling constants are also sensitive to structural changes, and for alkyl and aryl compounds the couplings decrease in the order 1J > 3J > 2J > 4J. The 13C chemical shift values and the magnitude of tin–carbon coupling constants are shown to be solvent‐dependent. The 13C spectra of the isotopically enriched compounds show that the degree of isotopic enrichment and the nature of the isotope used (magnetic or non‐magnetic) are reflected in the spectral pattern obtained. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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