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101.
V. Ya. Kavun N. F. Uvarov A. B. Slobodyuk V. K. Goncharuk A. Yu. Kotenkov I. A. Tkachenko A. V. Gerasimenko V. I. Sergienko 《Russian Journal of Electrochemistry》2005,41(5):501-509
Methods of (19F, 1H) NMR and impedance spectroscopy are used to investigate the internal mobility and ionic conduction in solid solutions arising in the system PbF2-ZrF4 and polycrystals KSnZrF7, Li(Na)(NH4)6Zr4F23, and M2ZrF6 (M = K, NH4). Factors responsible for the form of ionic motions and their energetics at 170–550 K are considered. It is established that the phase transitions in these compounds are connected with the crystal transition to a superionic state and that the high ionic (superionic) conductivity of beta phases is due to the diffusion of fluoride ions, ammonium cations, and possibly alkali metal cations. The obtained data testify to a substantial role of chainlike aggregation of anionic groupings and a variableness of structural mechanisms of formation of such chains in fluorozirconates for the development of translational diffusion in these compounds.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 573–582.Original Russian Text Copyright © 2005 by Kavun, Uvarov, Slobodyuk, Goncharuk, Kotenkov, Tkachenko, Gerasimenko, Sergienko. 相似文献
102.
The purpose of this paper is to present a new primal extreme point algorithm for solving assignment problems which both circumvents and exploits degeneracy. The algorithm is based on the observation that the degeneracy difficulties of the simplex method result from the unnecessary inspection of alternative basis representations of the extreme points. This paper characterizes a subsetQ of all bases that are capable of leading to an optimal solution to the problem if one exists. Using this characterization, an extreme point algorithm is developed which considers only those bases inQ. Computational results disclose that the new algorithm is substantially more efficient than previously developed primal and primal-dual extreme point (simplex) methods for assignment problems. 相似文献
103.
Two-dimensional capillary electrophoresis was used for the separation of proteins and biogenic amines from the mouse AtT-20 cell line. The first-dimension capillary contained a TRIS–CHES–SDS–dextran buffer to perform capillary sieving electrophoresis, which is based on molecular weight of proteins. The second-dimension capillary contained a TRIS–CHES–SDS buffer for micellar electrokinetic capillary chromatography. After a 61-s preliminary separation, fractions from the first-dimension capillary were successively transferred to the second-dimension capillary, where they further separated by MECC. The two-dimensional separation required 60 min. 相似文献
104.
Emerging fields of biochemical research, such as metabolomics, present challenges to current separation technologies because of the large number of metabolites present in a cell and their often low (submicromolar) concentration. Although capillary electrophoresis (CE) holds great promise as the method of choice for high-resolution separations of biological samples, it suffers from poor concentration sensitivity, especially with the use of UV detection. In CE, sweeping and dynamic pH junction represent two complementary on-line focusing techniques that have been used for sensitivity enhancement of hydrophobic and weakly acidic analytes, respectively. However, the application of either the sweeping or dynamic pH junction technique alone might, in some cases, be less effective for the analysis of certain sample mixtures. Recent work in the development of a hyphenated dynamic pH junction-sweeping technique is presented as an effective on-line method of preconcentration suitable for both hydrophilic (anionic) and hydrophobic (neutral) analytes. Sensitive analyses of flavin metabolites by CE with laser-induced fluorescence (LIF) detection is demonstrated in various biological matrixes, including cell extracts of Bacillus subtilis, pooled human plasma, as well as heat-deproteinized flavoenzymes. Enhanced analyte band narrowing and improved sensitivity is achieved for flavins using dynamic pH junction-sweeping compared to either sweeping or dynamic pH junction alone. This results in over a 1200-fold improvement in sensitivity relative to conventional injection methods, giving a limit of detection (LOD, defined as S/N = 3) of about 4.0 x 10(-12) M. Strategies for sensitive and more comprehensive analyses of other cell metabolites, including nucleotides, coenzymes, and steroids, are also discussed when using on-line focusing techniques in conjunction with multiplexed CE and UV detection. 相似文献
105.
The main purpose of this paper is to present accurate infrared integrated intensities of liquid toluene, C6H5CH3, at 25 °C. Also presented are the decadic molar absorption coefficients, Em, the real and imaginary dielectric constants, ε′ and ε″, and the real and imaginary molar polarizabilities, ′m and ″m. Integrated intensities were determined as Cj, the area under bands in the spectrum, for all bands between 4800 and 440 cm−1. The contributions from the different bands were separated by fitting the spectrum with classical damped harmonic oscillator bands. The uncertainties in the integrated intensities of most bands are estimated to be 5–10%, with the uncertainties in very weak bands and in shoulders possibly up to 100%. The intensity that should be assigned to the fundamentals is more difficult to estimate due to Fermi resonance with overtone and combination bands, and a best estimate is given. The integrated intensities of the fundamental vibrations and the corresponding transition dipole moments are summarized and are compared with literature values for the gas. 相似文献
106.
A high-powered, microwave-induced nitrogen–oxygen plasma (N2–O2–MIP) generated by using an Okamoto cavity at atmospheric pressure was investigated when the observation height, the flow rate of carrier gas, and the oxygen content were varied as the experimental parameters. The emission characteristics of the plasma were evaluated with regard to the excitation temperature and the intensity ratio of atomic line to ionic line. The excitation temperature of the N2–O2–MIP was in the range of 5100–5700 K when the oxygen content was varied from 0 to 30% at the observation height of 7 mm and the carrier gas flow rate of 0.6 l/min. The intensity ratio of atomic line to ionic line was elevated with an increase in the oxygen content. 相似文献
107.
流动注射萃取火焰原子吸收光谱法测定硫酸镍电解液中微量铅 总被引:1,自引:4,他引:1
本文采用流动注射在线萃取火焰原子吸收光谱法测定硫酸电解液中微量铅,考察了水相介质,共存离子,萃取装置,相比等因素的影响。分析含铅1.4mg/L和0.16mg/L的试样,分析值的相对标准偏差(n=10)分别为3.9%和12.3%,方法检出限为0.024mg/L。 相似文献
108.
Development of a stabilized low temperature infrared absorption cell for use in low temperature and collisional cooling experiments 总被引:1,自引:0,他引:1
Valentin A Henry A Claveau C Camy-Peyret C Hurtmans D Mantz AW 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(14):227-3482
We have constructed a stabilized low temperature infrared absorption cell cooled by an open cycle refrigerator, which can run with liquid nitrogen from 250 to 80K or with liquid helium from 80K to a few kelvin. Several CO infrared spectra were recorded at low temperature using a tunable diode laser spectrometer. These spectra were analyzed taking into account the detailed effects of collisions on the line profile when the pressure increases. We also recorded spectra at very low pressure to accurately model the diode laser emission. Spectra of the R(2) line in the fundamental band of 13CO cooled by collisions with helium buffer gas at 10.5K and at pressures near 1 Torr have been recorded. The He-pressure broadening parameter (gamma(0) = 0.3 cm(-1) atm(-1)) has been derived from the simultaneous analysis of four spectra at different pressures. 相似文献
109.
110.
文中通过对变频控制直接膨胀式太阳能热泵的数值模拟,指出PV/T- SAHP系统实现变频控制从而解决太阳能热泵集热器面积与压缩机的容量不匹配的关键问题是找到系统集热/蒸发器的MSS线.为变工况下太阳能热泵系统的研究提供参考. 相似文献