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21.
The effect of electrolytes on the sensitivity of the thermal-lens determination in aqueous solutions
A. A. Zhirkov S. N. Bendrysheva M. A. Proskurnin N. Yu. Ragozina B. K. Zuev 《Moscow University Chemistry Bulletin》2009,64(2):87-92
The effect of several common surfactants (SDS, Triton X-100, Brij-35, and Tween 80) as modifiers of thermooptical properties of aqueous solutions on parameters of the thermal-lens analytical determination of several model systems is studied. Selection criteria for the compositions of modified aqueous media for thermal-lens analytical trace determination are discussed. The increase in the metrological parameters of thermal-lens measurements in nonionic-surfactant solutions is comparable with that for organo-aqueous mixtures. A twofold decrease in the limits of detection compared to aqueous solutions observed in 2.5 wt % surfactant solutions is achieved. 相似文献
22.
We have measured the in-plane resistivity of Bi2Sr2CaCu2O8+δ and Tl2Ba2 CaCu2O8+δ single crystals in the temperature range 70–300 K. The thermodynamic fluctuations in the conductivity of both the samples
start around ∼ 125 K. We find the Lawrence and Doniach [1] model to be inadequate to describe the fluctuation conductivity
in these materials. The modification suggested by Ramallo et al [4] where by the conductivity is enhanced due to the presence of two superconducting layers in each unit cell is also not
adequate. We suggest the fluctuation conductivity to be reduced due to the reduction in the density of states (DOS) of the
quasiparticles which results due to the formation of Cooper pairs at the onset of the fluctuations. The data agrees with the
theory proposed by Dorin et al [5] which takes into account this reduction in DOS. 相似文献
23.
Clover detector has been used as a Compton polarimeter to measure the linear polarization of γ-rays produced in heavy ion
fusion reaction. The polarization sensitivity of the clover detector has been measured over γ-ray energies ranging from 386
to 1368 ke V. The E1 multipolarity of the 1117 keV transition in 99Rh has been established using this polarimeter. This has resulted in the assignment of negative parity to the band head at
3710 keV in 99Rh. 相似文献