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31.
An electrochemical pathway to prepare circular planar 90Sr/90Y sources for the calibration of surface contamination monitors 总被引:1,自引:0,他引:1
Manoj Kumar Shyamala S. Gandhi J. Nuwad J. Udhayakumar Ashutosh Dash 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):709-719
In this communication, we describe a novel method to prepare circular planar 90Sr/90Y sources (? = 16 mm) exploiting the intrinsic properties of the anodized titanium to electro-deposit predicted quantity of 90Sr activity from an aqueous solution. The influences of various experimental parameters such as pH of the electrolyte, applied current density, electrodeposition time and carrier strontium concentration were thoroughly investigated to arrive at a condition resulting optimal deposition of the 90Sr/90Y activity on the substrate. An optimized electrochemical procedure to prepare ~3.7 MBq (~0.1 mCi) of circular planar 90Sr/90Y sources commensurate with regulatory safety requirement has been the positive outcome. 相似文献
32.
33.
Oxidation of 1 with perbenzoic acid (p-toluene-sulphonic acid monohydrate as catalyst) provided novel oxetalactones 4 and 5 along with compounds 2 and 3. Treatment of 2 with perbenzoic acid yielded 4. A probable pathway for the formation of 4 from 1 involving the intermediacy of 2 has been suggested. 相似文献
34.
Summary Exact robustness studies against non-normality have been carried out for test of independence based on the four multivariate
criteria: Hotelling's trace,U
(p)
, Pillai's trace,V
(p)
, Wilks' criterion,W
(p)
, and Roy's largest root,L
(p)
. The density functions ofU
(p)
,W
(p)
andL
(p)
have been obtained in the canonical correlation case and further the moments ofU
(p)
and m.g.f. ofV
(p)
have been derived. All of the study is based on Pillai's distribution of the characteristic roots under violations. Numerical
results for the power function have been tabulated for the two-roots case. Slight non-normality does not affect the independence
test seriously.V
(2) is found to be most robust against nonnormality.
Yu-Sheng Hsu is now with Georgia State University, Atlanta. 相似文献
35.
36.
P. K. C. Pillai Brijesh K. Gupta Malti Goel 《Journal of Polymer Science.Polymer Physics》1981,19(9):1461-1470
The thermally stimulated current (TSC) technique has been used to study solvent-cast blends of a cellulose derivative with a vinyl polymer. TSC peaks are observed at 56, 80, and 120°C. Their origin is investigated because the TSC spectra of the blends differ from the spectra of the individual components. Data on blends with components in the weight ratios 25:75, 50:50, and 75:25 indicate that the 50:50 blend shows the greatest polarization. The enhancement of depolarization currents observed on blending is explained on the basis of a Maxwell–Wagner–Sillars polarization due to increased heterogeneity in the structure. Effects of forming conditions (time, temperature, field) on polarization have been investigated. Activation energies and relaxation times are calculated; there is good agreement between the values obtained from the initial-rise and the full-curve methods. 相似文献
37.
This review surveys the evolution of gas chromatographyic procedures for the quantification of barbiturates as either the free acids or their derivatives obtained by direct and on-column reactions. Among the aspects discussed, some emphasis is placed on recognized and other sources of interference encountered during analyses. 相似文献
38.
39.
[reaction: see text] The pyridine-mediated reaction of dimethyl acetylenedicarboxylate and cyclobutene-1,2-diones affords selective access to either hexasubstituted benzene derivatives or cyclopentenedione derivatives depending on the concentration of pyridine. 相似文献
40.
[reaction: see text] Pyridine catalyzes the reaction of 1,2-diaryl diones with dimethyl butynedioate to afford diaroyl maleates. This unprecedented rearrangement involves a unique benzoyl migration and proceeds with complete stereoselectivity. 相似文献