佐藤根 大士

A new synthesis route to hydroxyapatite microsphere was proposed. Starting from the W/O emulsion system, micron-sized precursor particles were formed autonomously. It was clarified that pH of water during hydrothermal treatment can affect the morphology of resultant hydroxyapatite particles. Particles of irregular shape could be obtained via hydrothermal treatment under ambient pH, by contrast under high-pH conditions resultant particles retain the spherical morphology of precursor particles. It was also clarified that obtained hydroxyapatite particles have negatively charged surface, which is opposite to those by general synthesis method such as precipitation. Eventually it was confirmed that lysozym which is positively charged protein can be adsorbed on the obtained hydroxyapatite particle but albumin which is negatively charged can never be adsorbed.

The measured values of apparent viscosity of non-Newtonian fluids were discussed. Alumina slurries, CMC solutions and chocolates were used as non-Newtonian fluids, and their apparent viscosities were measured by a single cylinder rotational viscometer (B-type viscometer) and coaxial cylinder rotational viscometer (coaxial viscometer). The measured values by the B-type viscometer were larger than those by the coaxial viscometer in every sample, and the flow curves measured by the coaxial viscometer were well fitted by the power law model. The ratio of the apparent viscosities measured by both viscometers was correlated with the exponent in the power law model. Instead of the exponent, a new index defined by the measurement values of the B-type viscometer was proposed in order to estimate the true values measured by the coaxial viscometer. The ratio of the apparent viscosities could be correlated with the new index as well as the exponent. It has been revealed that the true apparent viscosity can be roughly estimated by the B-type viscometer by using the new index.