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81.
We propose a Veneziano-like model for VV reactions near threshold involving exchanges of 0– trajectories int- andu-channels. The model is applied to , , , and processes. The model in its simplest form cannot account for the disparities in the cross sections for
andK
*+
K
*– and for 00 and +–. Further refinements of the model are suggested. 相似文献
82.
83.
The adsorption behavior and differential pulse cathodic adsorptive stripping voltammetry of the pesticide Chlorpyrifos (CP)
were investigated at the hanging mercury drop electrode (HMDE). The pesticide was accumulated at the HMDE and a well-defined
stripping peak was obtained at –1.2 V vs Ag/AgCl electrode at pH 7.50. A voltammetric procedure was developed for the trace
determination of Chlorpyrifos using differential pulse cathodic adsorptive stripping voltammetry (DP-CASV). The optimum working
conditions for the determination of the compound were established. The peak current was linear over the concentration range
9.90 × 10–8– 5.96 × 10–7 mol/L of Chlorpyrifos. The influence of diverse ions and some other pesticides was investigated. The analysis of Chlorpyrifos
in commercial formulations and treated waste water was carried out satisfactorily
Received: 10 July 1997 / Revised: 1 April 1998 / Accepted: 6 April 1998 相似文献
84.
S. Ravi S. Ravi A. K. Deepa A. K. Deepa S. Susheela S. Susheela P. V. Achuthan P. V. Achuthan S. Anil Kumar U. Jambunathan 《Journal of Radioanalytical and Nuclear Chemistry》2006,268(1):79-82
Summary A method has been developed for the estimation of 90Sr in reprocessed uranium oxide samples obtained from the Purex processing of natural uranium spent fuel discharged from the
research reactor. The method employs a combination of precipitation and solvent extraction procedure to eliminate other beta-impurities
prior to resorting to the estimation of 90Sr by beta-counting. 106Ru was eliminated by volatalizing with perchloric acid, uranium was removed by carrier precipitation with strontium as sulphate.
The sulphate precipitate was converted to carbonate and dissolved in nitric acid. 234Th and 234Pa were eliminated by synergistic solvent extraction using tri-n-butyl phosphate and thenoyl trifluoroacetone extractant mixture
in xylene. An iron scavenging step was included to remove any residual impurities. Finally, strontium is precipitated as SrC2O4. H2O. The separated 90Sr activity was followed to check the equilibrium growth of 90Y. 相似文献
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P. Ravi Girish M. Gore Surya P. Tewari Arun K. Sikder 《Journal of heterocyclic chemistry》2013,50(6):1322-1327
We report herein a facile, rapid, and environmentally friendly synthesis of nitropyrazoles in good yields using silica‐bismuth nitrate and silica‐sulfuric acid‐bismuth nitrate at room temperature for the first time. The relatively non‐toxic nature, ease of handling, easy availability, and low cost make the present procedure attractive for the nitration of a wide variety of diazoles in the drug and pharmaceutical industries. 相似文献
88.
A high‐performance liquid chromatographic (HPLC) method for enantioseparation of bupropion was developed using two isothiocyanate‐based chiral derivatizing reagents, (S)‐1‐(1‐naphthyl) ethyl isothiocyanate, (S)‐NEIT, and (R)‐α‐methyl benzyl isothiocyanate, (R)‐MBIT. The diastereomers synthesized with (S)‐NEIT were enantioseparated by reversed‐phase HPLC using gradient elution with mobile phase containing water and acetonitrile, whereas diastereomers synthesized with (R)‐MBIT were enantioseparated using triethyl amine phosphate buffer and methanol. Derivatization conditions were optimized and the method was validated for accuracy, precision and limit of detection. The limit of detection was found to be 0.040–0.043 µg/mL for each of the diastereomers prepared with (S)‐NEIT. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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