Takashi Mitamura

Formation mechanism of ZrSiO4 powders

The formation mechanism of ZrSiO4 powders from ZrO2 and colloidal SiO2 sols has been studied. The change in the ZrSiO4 yield rate with seeding and non-seeding has also been investigated. The induction period of the ZrSiO4 yield-rate curve corresponded to the n=1 region, a simple nucleation region, on the Avrami plot. The n=1 region was a rather wide range at 1200–1300°C and the nucleation reaction was promoted in this temperature range. It was found that the ZrSiO4 yield rate became high, even if seeding was not used, when the heating rate was controlled at less than 1 °C min−1.

The relationship between the photocurrent of the chloroplast - methyl viologen photoelectrochemical system and its activities of photosystems I and II.

gations1) that the inactivation of the photosynthetic electron transport systems (PETS) of the isolated chloroplasts is mainly attributable both to photochemical inactivation and to thermal destabilization. The study reported here is the relationship between the decrease of the photocurrent for the photoelectrochemical cell, of which the anolyte was madeup of isolated chloroplasts and methyl viologen, and the changes in the activities of photosystem I (PS-I) and photosystem II (PS-II) in PETS of the chloroplasts. The procedures for the preparation of Class II chloroplasts from fresh spinach leaves6* and the determination of the chlorophyll concentration7) were essentially similar to those previously described.5) Glucose oxidase (EC 1. 1.3.4) was purchased from Sigma and 3-(3,4-dichlorophenyl)1,4-dimethylurea (DCMU) was a generous gift from

Calculations of Laue Patterns using Object Windows for C

The software which simulates Laue patterns obtained by X-ray diffraction on extensive crystals was developed. As an example applying this software, the crystal orientation of RS-mandelic acid recrystallized from aqueous solution was determined and the atomic arrangements on crystal surfaces were revealed. The crystal growth mechanism was discussed on the basis of hydrogen bonds.

Simulation of Crystal Structure, Surface Geometry and Electron Diffraction using the Personal Computer (NEC - PC9801)

Basic tools in characterizing ultrafine particles used as a catalyst or an adsorbent as well as understanding surface phenomena were developed. A description of how to draw the atomic arrangement of the arbitrary crystal plane has also been given.

Synthesis of Zn-Fe Ferrite Powders by Thermite Method.

A new technique for synthesizing ZnsFe3-xO4powders from α-Fe2O3 and Zn under an argon flow by the thermite method is presented. The ZnxFe3, O4 fine powders (O.3 to O.6μm) of single phase were successfully synthesized at 500 °C for 3 h using the powder mixture of Zn/α-Fe2O3=0.35 (molar ratio). The saturation magnetization and coercive force of the ZnxFe3-xO4 powders were 97 emu/g and O.11 kOe, respectively.