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    Quadrupole moments in chiral material DyFe3(BO3)4 observed by resonant x-ray diffraction

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    By means of circularly polarized x-ray beam at Dy L3 and Fe K absorption edges, the chiral structure of the electric quadrupole was investigated for a single crystal of DyFe3(BO3)4 in which both Dy and Fe ions are arranged in spiral manners. The integrated intensity of the resonant x- ray diffraction of space-group forbidden reflections 004 and 005 is interpreted within the electric dipole transitions from Dy 2p3 to 5d and Fe 1s to 4p, respectively. We have confirmed that the 2 handedness of the crystal observed at Dy L3 and Fe K edges is consistent with that observed at Dy M5 edge in the previous study. By analyzing the azimuth scans of the diffracted intensity, the electronic quadrupole moments of Dy 5d and Fe 4p are derived. The temperature profiles of the integrated intensity of 004 at the Dy L3 and the Fe K edges are similar to those of Dy-O and Fe-O bond lengths, while that at the Dy M5 edge does not. The results indicate that the helix chiral orientations of quadrupole moments due to Dy 5d and Fe 4p electrons are more strongly affected by the crystal fields than Dy 4f

    Spectrophotometric determination of copper after separation by adsorption of its APDC complex on naphthalene

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    The copper APDC complex was adsorpted on microcrystalline naphthalene to determine the trace amounts of copper. The complex has an absorption maximum at 435 nm. The optimum pH range for the adsorption is 1.5-10.5. Beer's law was obeyed over the range of 2.5-48 μg of copper in 10 ml of dimethylformamide. The molar absorptivity was 1.3 xlO 4 l·mol -1·c-m1 ,the sensitivity of the complex as expressed by the Sandell's notation being 4.8xlO-3 μg of copper per ㎠. Sample solution ontaining 25 μg of copper was analyzed 10 times by the recommended procedure. The mean absorbance was 0.500 with relative standard deviation of 0.89%. The other factors such as amounts of reagent and naphthalene, standing time, shaking time and diverse ions were studied
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