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Particle surfaces of mineral aerosols are important reaction sites in the atmosphere. Previous studies suggested that calcite in aerosols, which are emitted during dust periods, neutralizes sulfuric acid. In this study, depth-dependent X-ray absorption fine structure spectroscopy for individual particles was employed to determine calcium (Ca) species at particle surface and in the bulk ofindividual particles, using an X-ray microbeam measured in the conversion electron yield and fluorescence yield modes, which is a powerful method to understand chemical processes at aerosol surfaces.

X-ray diffraction patterns and LIII-edge x-ray absorption near edge structure (XANES) spectra of YbInAu2 and LuInAu2 compounds have been measured at high pressure and room temperature using a diamond anvil cell and a synchrotron radiation at SPring-8. YbInAu2 is more compressible at pressures lower than 4 GPa than above it; the evaluated bulk modulus by Birch-type equation of state is 54-7 GPa which is one-half of that of the LuInAu2 (112.5 GPa). The mean valence v of Yb ion in YbInAu2 determined by the XANES measurement is an increasing function of pressure: 2.71(2) at normal pressure and 2.94(2) at 10 GPa. The rate of increase in v with pressure is two times larger at pressures below 4 GPa than that above 4 GPa. However, the v is described by a linear increasing function of the lattice compression: v = v0+2.9 | ΔV/V0| where v0 is 2.71. The extrapolation to the trivalent state gives the critical pressure of 13 GPa. [ABSTRACT FROM AUTHOR]

A thorough study of the magnetocaloric effect (MCE) in a colossal magnetoresistive compound of La0.7Sr0.3Mn0.98Ni0.02O3 has been made. The large magnetic entropy change of 7.65 J/kg K upon an applied field of 70 kOe has been found to occur at 350 K, which allows magnetic refrigeration at room temperature. It is interesting to note that, even in high magnetic fields, the magnetic entropy change versus temperature distribution is much more uniform than that of gadolinium and several polycrystalline perovskite manganites, which is desirable for an Ericson-cycle magnetic refrigerator. It is found that such a small amount (∼2%) of substitution of Mn3+ by a magnetic ion (Ni3+ or Co3+) in the perovskite manganite can favor the spin order and hence the MCE. Undoubtedly, this observation opens a window to explore the active magnetic refrigeration at high temperatures. [ABSTRACT FROM AUTHOR]

The valency of Yb ion in YbIn[Au.sub.2] is determined by the Yb [L.sub.III]-edge x-ray absorption near edge structure spectroscopy at high pressure and the lattice compression curves of YbIn[Au.sub.2] and LuIn[Au.sub.2] compounds are observed by the x-ray diffraction measurement using intense synchrotron radiation x-ray sources. The results have shown that the valence state of Yb ion in YbIn[Au.sub.2] is strongly correlated to the unit-cell volume so that the magnetic 4[f.sup.13] state is stabilized at high pressure.

The magnetocaloric effect (MCE) in a colossal magnetoresistive compound of La(sub 0.7) Sr(sub 0.3)Mn(sub 0.98)Ni(sub 0.02)O(sub 3) is studied. The large magnetic entropy change of 7.65 J/kg K upon an applied field of 70 kOe is found to occur at 350 K, which allows magnetic refrigeration at room temperature.

The mineralization process of the osseous layer, which is highly calcified in vivo, was successfully imitated by the immersion process of the decalcified fish scales in simplified simulated body fluid (SSBF). An alkali treatment was used to modify the native collagen in the decalcified Tilapia fish scale. After the alkali treatment, the mineralization was facilitated in SSBF. The XRD patterns and SEM-EDS observation results demonstrated that the externally-mineralized layers by the immersion process were highly similar to the osseous layer containing lower-crystalline hydroxyapatite, suggesting that the simple biomimetic precipitation process was developed.