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181.
B. R. Harvey M. B. Lovett S. J. Boggis 《Journal of Radioanalytical and Nuclear Chemistry》1987,115(2):357-368
Selected experiences in the control of contamination and the threat it poses to the quality of analytical date are discussed in the context of the whole analytical process from collection of marine environmental samples, through handling and radiochemical separation, to the final interpretation of results. Examples include a demonstration of the contamination introduced during sediment core sectioning, contamination of sea water by a ship's pumping system, and the effect of filtration on the apparent partitioning of radionuclides between solid and liquid phases of sea water. 相似文献
182.
Capillary Electrophoresis Chiral Separation for Enantiomeric Purity Determination of a Basic Drug in Pharmaceutical Formulations 总被引:1,自引:0,他引:1
Capillary electrophoresis using a running buffer composed of β-cyclodextrin as the chiral selector and ethanolamine mesylate at pH 9.6 is being used to monitor the stereochemical stability of a hydrophobic drug, containing two chiral centers, in two different formulated self-emulsifying drug delivery system (SEDDS) products. The separation takes place in less than 25 min. Strategies for enhancing the method reproducibility and detection sensitivity in the lower potency formulation are presented. The results demonstrating the specificity, assay precision, recovery, linearity and range achieved during the method validation experiments are presented in this paper.Presented at: CE in the Biotechnology and Pharmaceutical Industries: 7th Symposium on the Practical Applications for the Analysis of Proteins, Nucleotides and Small Molecules, Montreal, Canada, August 12–16, 2005. 相似文献
183.
184.
R. S. Martynov Yu. M. Nechepurenko 《Computational Mathematics and Mathematical Physics》2006,46(7):1155-1167
For a discrete linear stochastic dynamical system, computation of the response matrix to the external action from a subspace using given observational data is examined. An algorithm is proposed and substantiated that makes it possible to improve the numerical accuracy and to reduce the amount of observational data compared to the general case where an arbitrary external action is allowed. As an illustration, a discrete system arising in the analysis of a linear stochastic dynamical continuous-time system is considered more thoroughly. Some numerical results are presented. 相似文献
185.
J.R. Cooper 《Journal of Molecular Spectroscopy》2006,239(1):51-58
The ν9 fundamental band of ethane occurs in the 12 μm region. It is the strongest band of ethane in a terrestrial window and is commonly used for the identification of ethane in the Jovian planets. The ν9 + ν4 − ν4 band occurs in the same region; neither can be analysed as an isolated band, since both are embedded in the torsional bath of the ground vibrational state. We report here two global fit models including data from both of these bands as well as the ν3 fundamental and the ν4, 2ν4 − ν4, and 3ν4 torsional transitions. The first is restricted to −5 ? KΔK ? 15 in the hot band and gives an excellent fit to the included data. Three resonant interactions are identified in this fit—a Coriolis interaction with two resonant cases between the ν9 torsional stack and that of the ground vibrational state (gs) and a resonant Fermi interaction between the ν3 fundamental and the gs. Hot band lines with KΔK < −5 are influenced by a fourth perturbation, with a crossing at −11 < KΔK < −10, which has been attributed to an interaction with the ν12 fundamental. A second fit, demonstrating a promising treatment of this interaction, is also presented. 相似文献
186.
We show that when polystyrene is exposed (for 15–60 sec) to a UV laser light beam (λ = 248 nm), its absorption and luminescent
properties change significantly. In the irradiated polymer, optical centers are formed with absorption bands in the 280–460
nm region and fluorescence bands in the 330–520 nm region. We have established the chemical structure of the optical centers
for fluorescence of polystyrene.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 54–58, January–February, 2006. 相似文献
187.
The present work has a double aim. On the one hand, we call attention on the relationship existing between the Ashtekar formalism and other gauge-theoretical approaches to gravity, in particular the Poincaré Gauge Theory. On the other hand, we study two kinds of solutions for the constraints of General Relativity, consisting of two mutually independent parts, namely a general three-metric-dependent contribution to the extrinsic curvature K
ab
in terms of the Cotton–York tensor, and besides it further metric independent contributions, which we analyze in particular in the presence of isotropic three-metrics. 相似文献
188.
R. U. Khafizov N. Severijns O. Zimmer H. -F. Wirth D. Rich S. V. Tolokonnikov V. A. Solovei M. R. Kolhidashvili 《JETP Letters》2006,83(1):5-9
The aim of this work is the experimental observation of and research into a rare neutron mode, the radiative beta decay, where
a new particle, the radiative gamma quantum, is formed along with the expected decay products: a beta electron, a recoil proton,
and an antineutrino. The discovery of this rare neutron decay mode was conducted through identification of triple-coincidence
events: simultaneous registration of a beta electron, a proton, and a radiative gamma quantum. The ordinary neutron decay
was registered by double coincidences of a beta electron and a recoil proton. The statistics collected allow one to deduce
the branching ratio (BR) BR = (3.2 ± 1.6) × 10−3 (90% C.L.) in the gamma energy region greater than 35 keV. This value of BR is consistent with standard electroweak theory.
The text was submitted by the authors in English.
An erratum to this article is available at . 相似文献
189.
Yu. V. Vasil’ev R. R. Abzalimov Sh. K. Nasibullaev R. F. Tuktarov F. Hauke U. Reuther A. Hirsch T. Drewello 《Physics of the Solid State》2002,44(3):554-556
The formation and decay of negative molecular ions of azafullerenes and their hydrogenated derivatives are investigated by mass spectrometry. The mechanisms of resonant electron capture and the lifetimes of negative molecular ions with respect to the electron autodetachment in azafullerene molecules are discussed. A comparative analysis of the data obtained for azafullerenes and hydrogenated fullerene derivatives is carried out. 相似文献
190.
E. V. Gromachevskaya A. G. Sakhabutdinov V. G. Kul'nevich I. S. Arustamova R. B. Valeev B. A. Bazhenov 《Chemistry of Heterocyclic Compounds》1991,27(5):502-503
It was shown that the reaction of o-hyroxyphenyldiphenylmethanol with benzaldehyde labeled with 17O and 18O isotopes proceeds in such a way that oxygen atoms of the starting phenoloalcohol are retained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 632–633, May, 1991. 相似文献