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Biomedical subjects

T Kikegawa

Publications and source records attributed to T Kikegawa.

9 recordsLinked to original sources

Amorphouslike diffraction pattern in solid metallic titanium.

Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close to the alpha-beta-omega triple point in the P-T phase diagram. Amorphous Ti has been found to be thermally stable up to 1250 degrees C for at least 3 min at some pressures. By analyzing the conditions for producing amorphous elemental Zr and Ti, we observed a multi-phase-point amorphization phenomenon for preparing single-element bulk amorphous metals. The results reported may open a new way to preparing single-element bulk amorphous metals with a high thermal stability.

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Density measurements of liquid under high pressure and high temperature.

A new method for density measurements by means of X-ray absorption under high pressure and high temperature using synchrotron radiation has been developed. The method has been modified for a large-volume Paris-Edinburgh press and combined with intense high-energy X-rays at the ESRF. In order to overcome effects of deformation of sample shape under pressure, a ruby cylinder was used as a sample container. The density was determined from the intensity profile of transmitted X-rays. The densities of crystalline and liquid Bi were successfully measured up to 750 K at 1 GPa.

Journal Article↗

Application of an imaging plate to the large-volume press MAX80 at the Photon Factory.

An imaging plate was applied to the large-volume press MAX80 for quantitative in-situ X-ray diffraction. A combination of the two-dimensional detector with the uniform pressure and temperature environments of MAX80 and the wide energy range of synchrotron radiation resulted in high-quality diffraction data. A modified cell assembly with a disc-type heater was used to minimize extrinsic diffraction peaks from the surrounding materials. To demonstrate the high-quality data obtained from the imaging-plate system, the crystal structure of the high-pressure and high-temperature polymorph of the highly absorbing element bismuth (Bi IV) was determined.

Journal Article↗