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951.
Summary The liquid-liquid extraction of Mo(VI) from different acid solutions by zinc diethyldithiocarbamate in chloroform is described. This extractant allows the separation of nanogram to milligram quantities of Mo from even gram quantities of many other elements. The separation of Mo can be made selective by appropriate choice of the composition of the aqueous phase, by back-extraction of Mo and/or the coextracted elements, and by masking Mo with hydrogen peroxide. These techniques were adapted for the determination of Mo in several reference materials by radiochemical neutron activation analysis via 99Mo. 相似文献
952.
A. I. Golovashkin N. V. Anshukova L. I. Ivanova O. T. Maljuchkov A. P. Rusakov 《Czechoslovak Journal of Physics》1996,46(3):1191-1192
On the basis of new experimental studies of specific heat, magnetic properties and thermal expansion, it was shown that dielectric-metal phase transitions were the consequence of delocalization of the heavy holes located on metalapical oxygen bonds in the high-Tc oxide systems. The ordered arrays of such holes (CDW) results in the dielectric gaps in electron spectrum and anomalous negative thermal expansion. The free carriers introduced by doping can couple through excitations of these localized holes, (local bosons). The high-Tc superconductivity will possess anomalous Hc2(T) dependence and γ-type specific heat jump at Tc. This local bosons model is the basis for explanation of the obtained experimental data. 相似文献
953.
Gary L. Peterson 《Monatshefte für Mathematik》1996,121(3):275-290
AnI-E group is a group in which the endomorphism near-ring generated by the group's inner automorphisms equals the endomorphism near-ring generated by its endomorphisms. In this paper we shall completely determine the finite groups that are semidirect products of cyclic groups and areI-E groups. 相似文献
954.
955.
Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 2, pp. 137–144, March–April, 1995. 相似文献
956.
The features of positron annihilation in KCl crystals before and after radiation exposure is investigated. A significant increase in the efficiency of the ortho-vapor process of positronium state conversion is detected. A model is proposed for taking part in the ortho-vapor conversion of conduction electrons drawn into the conduction band by a positron field that affords a qualitative interpretation of the results obtained and permits values of the electron concentration in a spur to be obtained.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 98–102, July, 1988. 相似文献
957.
V. P. Germogenov O. M. Ivleva Ya. I. Otman L. E. Épiktetova 《Russian Physics Journal》1988,31(1):73-77
Studies have been carried out on the perfection of then-AlxGa1–xSb1–yAsy (0.12x0.26) layer grown on GaSb substrates under different conditions of lattice matching. During the relaxation of the mechanical stresses at first a system of tilt dislocations with a density of up to 5 · 105 cm–2 is formed while in thick layers (h 20 m) a network of misfit dislocations parallel to the heteroboundary is formed. The time required to dissolve a weighed amount of GaAs in the melt is shown to be of major importance for obtaining layers of a solid solution that are isoperiodic with the substrate. The entry of arsenic only in the initial portion of the epitaxial layer can reduce the dislocation density in the layer without decreasing the measured value of Aa. Dissolution of a weighed amount of GaAs in a Ga + Sb melt for two hours at T=730–750°C is sufficient to obtain layers of AlxGa1–xSb1–yAsy solid solution that are isoperiodic with the substrate.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 84–89, January, 1988.In conclusion, we thank L. V. Druzhinina for useful discussions as well as Z. V. Korotchenko, L. S. Khludkova, and F. S. Kim for assistance in the performance of the experiments. 相似文献
958.
It is proved that if the intrinsic zero-index of the Sasaki metric of a tangent bundleTM
n
isk, thenk is even andM
n
is the metric product of a Riemannian manifoldM
n–k/2 by a Euclidean spaceE
k/2, whileTM
n
is the metric product ofTM
n–k/2 byE
k
. An expression is obtained for the second fundamental forms of the imbeddingTF
l
TM
n
in terms of the second fundamental forms of the imbeddingF
l
M
n
and the curvature tensor ofM
n
. It is proved thatTF
l is totally geodesic inTM
n
if and only ifF
l
is totally geodesic inM
n
.Translated from Ukrainskií Geometricheskií Sbornik, Issue 28, 1985, pp. 12–32. 相似文献
959.
By the automorphic approach and the use of computer graphics, we carry out a qualitative analysis of finite-gap periodic solutions of the Kg equation. Graphs are constructed for multiphase solutions.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 165, pp. 31–41, 1987. 相似文献
960.
Let f be an entire function of genus zero, let (rk) be a sequence of Pólya peaks for N(r, f) of order <1. Then there exists a sequence r
k
~rk such that If for (rk) one takes a sequence of Pólya peaks for ln M(r, f) or for T(r, f), 1/2<<1, then the result ceases to be true.Translated from Teoriya Funktsii, Funktsional'nyi Analiz i Ikh Prilozheniya, No. 45, pp. 26–40, 1986. 相似文献