Application of a charge-coupled device photon-counting technique to three-dimensional element analysis of a plant seed (alfalfa) using a full-field x-ray fluorescence imaging microscope

A full-field x-ray fluorescence imaging microscope using a Wolter mirror was constructed at Photon Factory BL3C2. White x rays from a bending magnet were used to excite x-ray fluorescence and to enhance the x-ray fluorescence intensity. A photon-counting method using a charge-coupled device was applied to obtain an x-ray fluorescence spectrum at the image plane. The spatial distributions of some specific atoms such as Fe and Zn were obtained from photon-counting calculations. An energy resolution of 220 eV at the Fe Kalpha line was obtained from the x-ray fluorescence spectrum by the photon-counting method. The newly developed three-dimensional element mappings of the specific atoms were accomplished by the photon-counting method and a reconstruction technique using computed tomography.     

Environmentally Benign Carbonylation Reaction: Palladium-Catalyzed Hydroxycarbonylation of Aryl Halides and Benzyl Chloride Derivatives in Ionic Liquid Media

Palladium-catalyzed hydroxycarbonylations of aryl halides and benzyl chloride derivatives proceeded in ionic liquid media (l-butyl-3-methylimidazolium hexafluorophosphate (1), tetrafluoroborate (2) and Aliquat^®336 (3)). The palladium-catalyst/mixture could be recycled, after separation of the product by extraction with water. The use of ionic liquid media greatly increased the yield of benzoic acid in hydroxycarbonylation.     

Effect of impeller diameter on mean droplet diameter in circular loop reactor

Experiments in liquid-liquid dispersion were performed using a circular loop reactor designed for suspension polymerization. In order to vary widely differences in physical properties such as the viscosity, density, and interfacial tension between the two liquids concerned, polystyrene pellets were dissolved into the dispersed phase which consisted of a styrene monomer liquid. The diameter distributions and mean diameters of droplets formed were measured by stepwise changes in the impeller diameter. From these results, the effect of the impeller diameter on the breakup of droplets was determined. Correlations relating the mean droplet diameter to the operational conditions were derived.     

A metastable phase in thermal decomposition of Ca-deficient hydroxyapatite

We investigated the microstructural changes on an atomic length scale during thermal decomposition process of Ca-deficient hydroxyapatite (Ca-def HAp) by high-resolution transmission electron microscopy (HRTEM). Ca-def HAp was prepared by hydrolysis of -tricalcium phosphate. The Ca-def HAp had a whisker-like morphology 2–5 m in length and 0.1 m in diameter that was elongated along c-axis. Thicker planer defects parallel to the (100) plane of the HAp matrix were observed as precipitation in the sample annealed at 700 and 800 °C by HRTEM observation. Thickness of the precipitation was about 10 nm and the boundaries between the precipitation and HAp matrix was coincident. The periodicity in the precipitation was parallel to the (100) plane of the HAp matrix and measured to be 1.42 nm. Since the precipitation was observed only in the sample annealed at a narrow temperature range of 700–800 °C, it was regarded as a metastable phase formed on the thermal decomposition process. Absorption peaks in IR spectra of annealed Ca-def HAp containing the metastable phase appeared at 744 and 3538 cm^–1 due to non-stoichiometric HAp with high Ca/P molar ratio. Furthermore, the results of energy dispersive X-ray spectroscopy showed that the metastable phase had higher Ca/P molar ratio than that of the matrix and stoichiometric HAp. Therefore, the metastable phase could be identified as Ca-rich metastable phase. The presence of Ca-rich metastable phase was confirmed to be associated with the thermal decomposition process.     

On the use of high-Tc superconductors for Perot-Fabry mirrors coatings

In a very rough experiment using two MgO plates, coated with a 200 Å thick YBaCuO film to increase their reflectivity, and facing each other their YBaCuO films to make a Perot-Fabry (PF) interferometer, we have observed a 43% maximum transmission and a finesse around 33 at v=29 cm^?1, in good accordance with a new phenomenological model for YBaCuO. Much higher performances can be expected by optimizing the YBaCuO film thickness.