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1.
An analytical method for the separation and quantification of Sb(III) and Sb(V) using anion chromatography with ICP-MS is presented. The optimum conditions for the separation of the antimony species were established with 15 mmol/L nitric acid at pH 6 as eluent system on a PRP-X100 column. The retention times for antimony(V) and antimony(III) were 85 s and 300 s with detection limits of 0.06 microg/L and 0.29 microg/L, respectively. The proposed method was applied to cell extracts of Leishmania donovani, which were incubated with antimony(III) and antimony(V). Some metabolism seemed to occur within the cells. 相似文献
2.
In this paper we study a family of stochastic orders of random variables defined via the comparison of their percentile residual life functions. Some interpretations of these stochastic orders are given, and various properties of them are derived. The relationships to other stochastic orders are also studied. Finally, some applications in reliability theory and finance are described. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
3.
Moshe Shaked 《Annals of the Institute of Statistical Mathematics》1979,31(1):67-84
In this work we consider some familiar and some new concepts of positive dependence for interchangeable bivariate distributions.
By characterizing distributions which are positively dependent according to some of these concepts, we indicate real situations
in which these concepts arise naturally. For the various families of positively dependent distributions we prove some closure
properties and demonstrate all the possible logical relations. Some inequalities are shown and applied to determine whether
under- (or over-) estimates, of various probabilistic quantities, occur when a positively dependent distribution is assumed
(falsely) to be the product of its marginals (that is, when two positively dependent random variables are assumed, falsely,
to be independent). Specific applications in reliability theory, statistical mechanics and reversible Markov processes are
discussed.
This work was partially supported by National Science Foundation GP-30707X1. It is part of the author's Ph.D. dissertation
prepared at the University of Rochester and supervised by A. W. Marshall.
Now at Indiana University. 相似文献
4.
R. Knoll A. Shames S. D. Goren H. Shaked S. Cordier C. Perrin O. Hernandez T. Roisnel G. André R. K. Kremer A. Simon 《Applied magnetic resonance》2013,44(1-2):143-151
We have studied the magnetic cluster compound Nb6F15 which has an odd number of 15 valence electrons per (Nb6F12)3+ cluster core, as a function of temperature using nuclear magnetic resonance, magnetic susceptibility, electron magnetic resonance and neutron powder diffraction. Nuclear magnetic resonance of the 19F nuclei shows two lines corresponding to the apical Fa?a nucleus, and to the inner Fi nuclei. The temperature dependence of the signal from the Fi nuclei reveals an antiferromagnetic ordering at T < 5 K, with a hyperfine field of ~2 mT. Magnetic susceptibility exhibits a Curie–Weiss behavior with T N ~5 K, and μ eff ~1.57 μB close to the expected theoretical value for one unpaired electron (1.73 μB). Electron magnetic resonance linewidth shows a transition at 5 K. Upon cooling from 10 to 1.4 K, the neutron diffraction shows a decrease in the intensity of the low-angle diffuse scattering below Q ~0.27 Å?1. This decrease is consistent with emergence of magnetic order of large magnetic objects (clusters). This study shows that Nb6F15 is paramagnetic at RT and undergoes a transition to antiferromagnetic order at 5 K. This unique antiferromagnetic ordering results from the interaction between magnetic spins delocalized over each entire (Nb6F 12 i )3+ cluster core, rather than the common magnetic ordering. 相似文献
5.
In this paper the authors introduce and study a model of failures and repairs of units with discrete lifetimes. They suppose that a unit has a sequence of tasks to perform and that its lifetime is measured by the number of tasks performed before its final, fatal failure. Upon a failure the unit may be repaired (with some probability) and then it may attempt again to perform the current task. The unit dies when (with some probability) a repair cannot be completed. We derive some stochastic comparisons of pairs of such models. The stochastic comparisons are then applied for obtaining results regarding the inheritance of several aging properties by the repaired unit. Various examples illustrate the applicability of the model. Some variants of the model of this paper can be viewed as discrete analogues of the notion of imperfect repair. 相似文献
6.
The Q dependence of the magnetic form factor of Ho3+ in HoCrO3 was determined by inelastic neutron scattering. The method is compared with other techniques and the results are compared with those of other techniques and with theoretical calculations. 相似文献
7.
Two multivariate hazard rate stochastic orders are introduced and studied. Their meaning, properties, and relationship to other common stochastic orders are examined and investigated. Some examples that illustrate the theory are detailed. Finally, some applications of the new orders in reliability theory and in actuarial science are described. 相似文献
8.
Neutron diffraction and magnetic susceptibility measurements show NH4MnCl3 to be an antiferromagnet of type G with TN ∼ 105°K. The low temperature patterns reveal a tetragonal splitting and superlattice lines which were accounted for by assuming the space group to be P bnm. 相似文献
9.
An analytical method for the separation and quantification of Sb(III) and Sb(V) using anion chromatography with ICP-MS is presented. The optimum conditions for the separation of the antimony species were established with 15 mmol/L nitric acid at pH 6 as eluent system on a PRP-X100 column. The retention times for antimony(V) and antimony(III) were 85 s and 300 s with detection limits of 0.06 μg/L and 0.29 μg/L, respectively. The proposed method was applied to cell extracts of Leishmania donovani, which were incubated with antimony(III) and antimony(V). Some metabolism seemed to occur within the cells. 相似文献
10.
The Hazard Rate and the Reversed Hazard Rate Orders, with Applications to Order Statistics 总被引:1,自引:0,他引:1
In this paper we first point out a simple observation that can be used successfully in order to translate results about the hazard rate order into results about the reversed hazard rate order. Using it, we derive some interesting new results which compare order statistics in the hazard and in the reversed hazard rate orders; as well as in the usual stochastic order. We also simplify proofs of some known results involving the reversed hazard rate order. Finally, a few further applications of the observation are given. 相似文献