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141.
142.
In this study, a simple and sensitive method for the determination of arsenic in water samples was developed. The method is based on the formation of micro particles of Ethyl Violet and molybdoarsenate, which gives an apparently homogeneous blue color to the solution. The absorption of the excess dye gradually decreases due to its conversion to a colorless carbinol species under strongly acidic conditions. Consequently, the sufficiently low reagent blank enables the spectrophotometric determination of arsenic with the detection limit of 4 microg l(-1). The coefficient of variation for the spectrophotometry at 50 microg l(-1) was 3.5% (n = 5). Furthermore, it is possible to detect concentrations as low as 10 microg l(-1) of arsenic visually. Our method will be useful as a simple, rapid, and cost-effective field test of arsenic, requiring no complex apparatus or skilled laboratory support. 相似文献
143.
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145.
Kinetic equations for the one-particle distribution function of dilute gases and plasmas and evolution equations for the variance of their fluctuations are obtained from the BBGKY hierarchy equations by using Mori's scaling method in an extended form. 相似文献
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147.
A study of the free vibration of finite cylinders with elliptical cross section under external pressure is presented. The bucklng pressure is obtained as a special case in the free vibration analysis. The elliptical cross section is considered to be composed of two circular arcs, and the equations of a circular cylindrical shell are applied. Numerical examples are presented to examine the effect of out-of-roundness on the natural frequencies and the buckling pressure. 相似文献
148.
149.
H. Morita Y. Fukushima M. Yamamoto H. Fujimori 《Journal of magnetism and magnetic materials》1985,49(3):301-304
The magnetic anisotropy induced by magnetic field annealing was examined for amorphous (FexCo1-x)85Nb15 alloys produced by a sputtering technique. An appreciably large uniaxial anisotropy was observed even at x = 0. The anisotropy constant (Ku) obtained was 2.3x103 erg/cm3 at x=0, and it increased with x, showing a maximum of about 5.4x103 erg/cm3 near x = 0.2. This compositional change in Ku was explained in terms of the directional ordering of magnetic Fe-Co atom pairs under the negative nonmagnetic interaction energy leading to a precipitation. 相似文献
150.
The Kirkwood and Buff compressibility equation for multicomponent systems is applied to an assembly of ions and electrons, where the Coulomb potential is replaced by the Yukawa potential. It is then shown that the resulting formula gives the Watabe-Hasegawa-Chihara compressibility equation in the limit of infinitesimal damping constant of the Yukawa potential. 相似文献