No abstract

Hydrogen bonding in methanol clusters has been investigated by using inner-shell photoabsorption spectroscopy and density functional theory (DFT) calculations in the carbon and oxygen K-edge regions. The partial-ion-yield (PIY) curves of H(CH(3)OH)(n)(+) were measured as the soft x-ray absorption spectra of methanol clusters. The first resonance peak in the PIY curves, which is assigned to the sigma*(O-H) resonance transition, exhibits a 1.20 eV blueshift relative to the total-ion-yield (TIY) curves of molecular methanol in the oxygen K-edge region, while it exhibits a shift of only 0.25 eV in the carbon K-edge region. Decreased intensities of the transitions to higher Rydberg orbitals were observed in the PIY curves of the clusters. The drastic change in the sigma*(O-H) resonance transition is interpreted by the change in the character of the sigma*(O-H) molecular orbital at the H-donating OH site due to the hydrogen-bonding interaction.

The hydroxyapatite (HA) formation on the DNA molecules in SBF was examined. After immersion for four weeks in SBF at 36.5 °C, the HA crystallites of ~1-14 μm in diameter grew on the surface of DNA molecules. Various morphologies were successfully observed through scanning electron microscopy analysis. The Ca/P mol ratio (1.1-1.5) in HA was estimated by energy dispersive X-ray analysis. Original peaks of both of DNA and HA were characterized by Fourier transform infrared spectroscopy. The molecular orbital computer simulation has been used to probe the interaction of DNA with two charge-balancing ions, i.e., CaOH(+) and CaH2PO4(+). The adsorption enthalpy of the two ions on ds-DNA and/or ss-DNA having large negative value (~ -60 kcal/mol per charge-balancing ion) was the evidence for the interface in mineralization of HA in SBF.

Oriented (Ti,Sn)O 2 thin films with modulated microstructure were successfully synthesized on sapphire substrates by using sol-gel processing combined with spinodal decomposition. The degree of orientation of (Ti 0.5 Sn 0.5 )O 2 thin films increased in the following order: sapphire (0001),, and (0112). (Ti 0.5 Sn 0.5 )O 2 thin films underwent spinodal decomposition at 900°C by annealing. The variation of the 2 value of the 202 reflection of (Ti 0.5 Sn 0.5 )O 2 films showed the typical behavior of spinodal decomposition. The rate of spinodal decomposition of the (Ti 0.5 Sn 0.5 )O 2 films on sapphire (1120) was faster than that on sapphire (0112) substrates. The characteristic modulated microstructure was observed for the spinodally decomposed (Ti 0.5 Sn 0.5 )O 2 films on sapphire (0112) substrates by transmission electron microscopy. (Ti 0.3 Sn 0.7 )O 2 films on sapphire (0112) substrates were binodally decomposed during annealing at 1300°C.