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This article provides an overview of the incorporation and adsorption of arsenate and phosphate into iron oxides formed in aqueous solutions. Although arsenic (As) and phosphorus (P) and belong to the same group in the periodic table, As is usually toxic, whereas P is a biological element. Arsenate and phosphate ions can be incorporated into iron oxides through different routes, depending on the solution conditions. In aqueous solutions, the chemical state of Fe in iron oxides is FeII (ferrous) or FeIII (ferric), that of As is AsIII (arsenite) and AsV (arsenate), and that of phosphorus is PV (phosphate). The composition and structure of iron oxides, including ferric oxyhydroxides and hydroxides formed in aqueous solutions, are affected by solution conditions such as the electrochemical potential, pH, temperature, and the chemical state and composition of the relevant elements. Moreover, arsenate and phosphate ions are usually adsorbed on the surface of iron oxides in aqueous solutions, but the incorporation and adsorption of arsenate and phosphate ions in iron oxides cannot be easily explained using simple thermodynamic models. This is because these characteristics are accompanied by different stages of coprecipitation, incongruent dissolution of multicomponent iron oxides, and so on. Since hydrated iron-oxide particles are often very fine and poorly crystallized, they are difficult to filter. However, it has been shown that coarse polyhedral particles of hydrated iron oxide can be synthesized by oxidizing FeII ions. In addition, the coarse particles of hydrated iron oxide are transformed into agglomerates of fine FeIII oxides with a coarse outer shell by alkaline treatment, and these coarse porous iron-oxide particles exhibit good anion-adsorption capacity in aqueous solutions. The formation mechanisms of these different iron-oxide particles are discussed based on the results of the incorporation and adsorption of arsenate and phosphate ions in iron oxides in aqueous solutions. [ABSTRACT FROM AUTHOR]

To process ingots of FeGa alloy single crystals into wafers, Fe17% Ga alloy crystals were cut using multi-wire sawing or electric discharging and rolling. Further, their properties of magnetization and magnetostriction were analyzed using electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). It was observed that the magnetization and magnetostriction curves changed with increasing rolling reduction. Although magnetization was negligibly affected by deformation, the shape of the magnetostriction curve of the as-grown crystal could be modified by a slight reduction in rolling or a slight plastic deformation. EBSD results show that rolling introduced dislocations to form heterogeneous dislocation cell walls and decreased the surface roughness of the wafers. The pole figures obtained by XRD indicate that the samples were single crystals; however, the crystal orientation was different from the ideal orientation after rolling. Residual stress measurements using the cos ¡ method revealed that compressive and tensile stresses remained in the polycrystalline surface layers of the samples cut by multiwire sawing and electric discharging, respectively. Moreover, the stresses were affected by the tensile strains or magnetic fields when the residual stresses were relatively small in the sample. Although the magnetization and magnetostriction of a single crystal are affected by rolling, they are not significantly reduced by small rolling reductions. [ABSTRACT FROM AUTHOR]

Precise lattice constant measurements based on the Bond method for various types of diamond were performed with a recently reported compensation technique. For the measurements, a calibrated Si single crystal was used as a reference; it was placed in a chamber whose temperature was carefully controlled below the standard deviation σ of ±0.1 °C, including thermo-couple fluctuation of ±0.06 °C for ±σ, X-ray wavelength calibration was performed using the monochromator temperature. A calibration was also carried out for the instrumental value depending on the Bragg angle and it was applied to the 004 diffraction peak of diamond. The lattice constant of high quality insulating undoped IIa type diamond was 3.567095 ± 0.000017 Å (±2σ), which was larger than the previous data derived without above mentioned calibrations. The measurements were carried out for various types of diamond including high pressure high temperature (HPHT) grown crystals as well as crystals grown by the chemical vapor deposition (CVD) method. [ABSTRACT FROM AUTHOR]