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21.
Chlorocarbons were ionized through gas phase chemistry at ambient pressure in air and resultant ions were characterized using a micro-fabricated drift tube with differential mobility spectrometry (DMS). Positive and negative product ions were characterized simultaneously in a single drift tube equipped with a 3 mCi (63)Ni ion source at 50 degrees C and drift gas of air with 1 ppm moisture. Scans of compensation voltage for most chlorocarbons produced differential mobility spectra with Cl(-) as the sole product ion and a few chlorocarbons produced adduct ions, M (.-) Cl(-). Detection limits were approximately 20-80 pg for gas chromatography-DMS measurements. Chlorocarbons also yielded positive ions through chemical ionization in air and differential mobility spectra showed peaks with characteristic compensation voltages for each substance. Field dependence of mobility was determined for positive and negative ions of each substance and confirmed characteristic behavior for each ion. A DMS analyzer with a membrane inlet was used to continuously monitor effluent from columns of bentonite or synthetic silica beads to determine breakthrough volumes of individual chlorocarbons. These findings suggest a potential of DMS for monitoring subsurface environments either on site or perhaps in situ. 相似文献
22.
V.S. Krylov 《Journal of Electroanalytical Chemistry》1981,123(1):95-103
The problem of statistical mechanical averaging for the probability of the elementary act of an irreversible electron transfer reaction occurring at a metal/solution interface in the presence of specifically adsorbed electrochemically inert ions or dipole molecules is discussed in detail. Analytical expressions are derived for the polarization curve of the interface in the cases of localization of the ionic reactant centers both inside and outside the compact part of the double layer. Within the framework of the theory presented the available experimental data on electrochemical kinetics complicated by the specific adsorption of charged and neutral components of the solution are analyzed. 相似文献
23.
Thermal oxidative treatment enhances the activity of a schungite rock in the sorption of petrochemicals from aqueous solutions.
The effect of the thermal oxidative activation on the content and distribution of carbon in the rock and the dependence of
the sorption activity on the texture of sorbents were studied.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2233–2238, October, 2005. 相似文献
24.
V. A. Krylov 《Journal of Analytical Chemistry》2002,57(8):660-671
The current status of the analysis of high-purity volatile substances is considered. Two types of impurities in high-purity volatile substances were distinguished: molecularly dissolved substances and suspended particles. The main factors that restrict the limiting capabilities of analytical techniques were revealed. The attained detection limits were 10–8–10–10% for metal impurities, 10–4–10–8% for organic substances, 10–5–10–9% for water, and 10–5–10–7 for permanent gases. Suspended particles of 0.04–0.003 m in size were determined by light scattering. 相似文献
25.
A procedure was developed for the gas-chromatographic determination of hydrocarbons in silicon tetrafluoride of natural and isotopically enriched compositions. For improving the efficiency of the chromatographic determination of impurities, it was proposed that the major compound be removed from the test sample with the subsequent cryofocusing of impurity hydrocarbons. The detection limits of C1-C4 hydrocarbons were 2 × 10?6?6 × 10?6 vol %. 相似文献
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A method for numerical simulation of the motion of the plane liner in a magnetic compressor based on a combination of the transverse and longitudinal two-dimensional models is proposed. The method permits modeling the interaction of the liner ribbon with the rigid basement for the liner kinematic characteristics close to the experimental ones. Three different model are considered to justify the choice of the mathematical model of an elastoplastic body which would be suitable for solving similar problems. A series of computations is performed, and the results and scope of each of the models are analyzed. 相似文献
30.
A. N. Vtyurin A. S. Krylov S. V. Goryainov S. N. Krylova A. S. Oreshonkov V. N. Voronov 《Physics of the Solid State》2012,54(5):934-936
The Raman spectra of the elpasolite (Rb2KInF6) crystal have been studied in the pressure range from 0 to 5.3 GPa at a temperature of 295 K. A phase transition at a pressure of approximately 0.9 GPa has been found. An analysis of the variations in the spectral parameters has led to the conclusion that the phase transition to a distorted phase is accompanied by the doubling of the volume of the primitive cell of the initial cubic phase. Numerical calculations of the lattice dynamics in the Rb2KInF6 crystal have been performed. The numerical simulation has established that the phase transition at a pressure of 0.9 GPa is associated with condensation of the F lg mode. A probable high-pressure phase is the phase with space group C2/m. 相似文献