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V. K. Bel'skii E. V. Kharchenko A. N. Sobolev V. E. Zavodnik N. A. Kolomiets G. S. Prober L. P. Oleksenko 《Journal of Structural Chemistry》1991,31(5):791-795
Kiev State University and L. Ya. Karpov Physical Chemistry Research Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 5, pp. 116–121, September–October, 1990. 相似文献
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The current noise density S2 of a conductor in equilibrium, the Johnson noise, is determined by its temperature T: S2 = 4k(B)TG, with G the conductance. The sample's noise temperature T(N) = S2/(4k(B)G) generalizes T for a system out of equilibrium. We introduce the "noise thermal impedance" of a sample as the ratio deltaT(N)omega/deltaP(J)omega of the amplitude deltaT(N)omega of the oscillation of T(N) when heated by an oscillating power deltaP(J)omega at frequency omega. For a macroscopic sample, it is the usual thermal impedance. We show for a diffusive wire how this (complex) frequency-dependent quantity gives access to the electron-phonon interaction time in a long wire and to the diffusion time in a shorter one, and how its real part may also give access to the electron-electron inelastic time. These times are not simply accessible from the frequency dependence of S2 itself. 相似文献
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We report on time-resolved measurements of thermodynamic fluctuations in the number of particles in a nondegenerate Fermi gas. The gas is comprised of thermal quasiparticles, confined in a superconducting Al box by large-gap Ta leads. The average number of quasiparticles is about 10(5). This number fluctuates due to quasiparticle generation and recombination. The number is measured from the tunneling current through a barrier that bisects the box. The recombination time is independently measured by single-photon excitation and agrees with the frequency dependence of the fluctuations. 相似文献
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Measurement of amphotericin B in serum or plasma by high-performance liquid chromatography 总被引:5,自引:0,他引:5
A high-performance liquid chromatographic method for the analysis of amphotericin B in 25 microliters of serum or plasma is described. The procedure involves the addition of the internal standard, p-nitrobenzyloxyamine, to the sample followed by a precipitation of protein with acetonitrile. The supernatant is directly injected into a chromatograph attached to a reversed-phase mu Bondapak (Waters) column containing C18 packing. The mobile phase is a 60 : 40 mixture of a sodium acetate buffer (10 mM, pH 7.0)--acetonitrile, and we employ a flow-rate of 1.5 ml/min and a detection wavelength of 405 nm. Total analysis time per sample is 10 min. Coefficients of variation were found to be less than 4% for concentrations less than 2 mg/l. Analytical recoveries were between 75 and 80%. No drug or drug metabolite interference was found. The method will be used to study pharmacokinetic and pharmacodynamic data in a pediatric population. 相似文献
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