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[en] Highlights: • Solubility limits of chromium in silicate melts are given for a wide fO2 range. • Diffusivity of multivalent chromium were determined by square wave voltammetry. • Basicity and viscosity of the silicates affects the corrosion behavior of NiCr alloy. • Dissolution of Cr2O3 is kinetically limited by the diffusion of Cr in silicates.
[en] An absorption spectrometry coupled with flow injection analysis has been developed and tested for the analysis of the Cr2O72-/MnO4- mixtures. Even though one has to inject the sample twice into the FIA system and the process of the sample treatment is required to completely destroy the MnO4- ion for the analysis of the Cr2O72- ion, the new method has definite advantages over the current method. It utilizes only a single analytical wavelength (570 nm) and enables one to construct calibration curves which accurately follow the Bee's law over wide ranges of analytical concentrations of both ions (2.0x10-6 M∼8.0x10-3 M for Cr2O72- ion, 2.0x10-6 M∼4.0x10-3 M for MnO4- ion)
[en] Six column experiments were performed and seven breakthrough curves (BTCs) and seven displacement (desorption) curves (DPCs) of phosphate and U(VI) were obtained, which demonstrated the effects of phosphate and Cr3+ on the sorption and transport of U(VI) on a silica column at pH 3 and uranium concentration 10-5-10-6 mol/L of the influent. It was found that in the presence of phosphate sorbed preliminarily on the silica column, the amount of U(VI) sorbed on this column is significantly increased owing to the interaction of U(VI) with phosphate sorbed as compared with that in the absence of phosphate, and the breakthrough and the mean residence time of U(VI) on this column are similar to those in the absence of phosphate. While the effect of simultaneous injection of Cr3+ on the retardation of U(VI) on the silica column, the maximum concentration of BTC and the amount of U(VI) sorbed was found to be insignificant. Transport and sorption studies of U(VI) are important, since all uranium isotopes are radioactive, there is a need to understand the potential for migration away from radioactive waste storage and mill tailing sites. (author)
[en] The branch-like, feather-like BaCrO_4 nano-superstructures were synthesized with bioactive eggshell membrane as directing and assembly template. Studies on the two products revealed that they formed through the self-assembly of nanoparticles, and that the optical properties of the products were different from BaCrO_4 bulk materials
[en] In this paper the third-rank chromatic aberration coefficients of round electron lenses are analytically derived and numerically calculated by Mathematica. Furthermore, the numerical results are cross-checked by the differential algebraic (DA) method, which verifies that all the formulas for the third-rank chromatic aberration coefficients are completely correct. It is hoped that this work would be helpful for further chromatic aberration correction in electron microscopy.
[en] Calorimetric measurements of the enthalpies of reaction of Cs2CrO4 with aqueous nitric acid and of Cs2Cr2O7 with aqueous cesium hydroxide gave a mean value for the standard enthalpy of formation of cesium dichromate: ΔH0sub(f)(Cs2Cr2O7, c, 298.15 K) = -(499.79 +- 0.68) kcalsub(th) mol-1. Standard enthalpies of formation of Na2Cr2O7 and K2Cr2O7 have been recalculated from published results to be -(473.71 +- 0.92) and -(493.3 +- 0.8) kcalsub(th) mol-1, respectively, and ΔH0sub(f)(Rb2Cr2O7, c, 298.15 K) has been estimated to be -(492.0 +- 2.6) kcalsub(th) mol-1. Measurements of the enthalpy of solution of CsNO3 in HNO3(aq) suggest the need for additional studies of the enthalpy of dilution of CsNO3(aq). (author)