[in Japanese]

View full abstract

[in Japanese]

View full abstract

Hydroxyapatite (Ca10(PO)4(OH)2; HA) is known as the major component of human bones. Sintered HA with random crystal surface has already been used as a bone-repairing material which can directly bond to natural bones in bony defect. It has been known to be biocompatible and osteoconductive. If materials of HA could have the tailored specific crystal surface, the HA materials should have the advantage of adsorptive activity in comparison with the sintered HA. The authors will talk about various kinds of HA porous materials with tailored crystal surface prepared by the unique hydrothermal methods.

View full abstract

[in Japanese]

View full abstract

We have investigated on fabrication of porous hydroxyapatite (HAp) coated materials by using electrophoretic deposition (EPD) of composite particle and heat treatment. The compsite particle consists of a monodisperse polystyrene bead covered with HAp fine particles and is dispersed in ethanol-based solution. A uniform PS/HAp composite particle layer can be formed on a titanium substrate by the EPD process under the optimized conditions. After heating at 900 degree C, the HAp layer with a highly ordered macropores was coated on the substrate. An in vitro test using a simulated body fluid indicated that the porous layer had a good biocompatibility.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

Ferromagnetic materials can be expected to be useful as thermo seeds for hyperthermia of cancer, especially cancer located at deep parts of body, since they can generate heat by magnetic hysteresis loss to treat the cancer, when they are placed under an alternating magnetic field.Previously, we prepared ferromagnetic g-Fe2O3 microspheres by a precipitation from solution. It is, however, afraid that the microspheres implanted into a tumor may accumulate in the dorsal blood vessels of the patients owing their high density.In this study, we attempted to prepare ferromagnetic hollow particles by using an enzymatic reaction of ureaze. The obtained particle took a hollow structure, and its saturated magnetization and coercive force were 43 emu g-1 and 150 Oe, respectively. Its heat generation under an alternating magnetic field of 300 Oe,100 kHz was estimated to be 27 W g-1.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

Recently, it was found that an ethylene-vinyl alcohol copolymer (EVOH) modified with silane-coupling reagent and calcium silicate solution (CS) on its surface to be abundant in Si-OH groups and calcium ions, fomed bonelike apatite on its surface in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma. In this study, the apatite-forming ability of EVOH, a polyethylene (PE) and a poly(ethylene terephthalate) (PET) modified with only CS solution on their surfaces were investigated in SBF. EVOH and PET showed the apatite-forming ability, but not PE. However, all the examined polymers showed apatite-forming ability, when they are subjected to glow discharge before CS treatment. Adhesive strength between the apatite and EVOH substrate was approximately 1.6 MPa, irrespective of the treatment conditions, and the fractures occurred at the interface between the apatite and the substrate.

View full abstract

[in Japanese]

View full abstract

Redox state of Fe affects glass property and its control is very important in glass manufacturing process. Computational technique applicable to redox phenomenon in glass has been strongly wanted because experimental method is rather hard. It is experimentally known that Fe²⁺ shifts to Fe³⁺ in glass with increasing basicity. We report here how Fe redox state in soda-silicate glass responds to increasing Na₂O using recently developed fluc-q molecular dynamics method.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

Hardness of sol-gel derived silica inorganic-organic hybrid films has been evaluated using an indentation test machine. The intrinsic hardness of the hybrid films was obtainable when the thickness of the films was sufficiently larger that of the indentation depth. The hardness of the films increased with increases in heat treatment time and in the amount of inorganic component. The increase in the hardness of the film reflects the development of Si-O-Si network structure.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

Excessive-light-induced melt down was observed in a carbon-coated TeO₂ glass segment formed between a pair of optical fiber end-faces. This structure was made by splicing single-mode silica fibers through TeO₂ glass melt to form a necked bridge, which was coated with carbon-containing paint after quenching it. Optical fusing action was induced by 0.3-1.5 W of CW light (1.54um) and its output power dropped by 12 dB on average. Optical decoupling seems to be induced bynot only deformation but also crystallization of the glass bridge. Its quite a high insertion loss of about 2dB can be reduced by introducingsome refractive index modulations into the present structure.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

Copper-Alkali ion-exchange was carried out using copper stain for sodalime silicate and borosilicate glasses. The ion-exchanged glasses were colorless with optical quality indicating that monovalent copper ions were selectively incorporated. Light propagation was observed for the ion-exchanged region with prism coupler method. The optical propagation loss was estimated by measuring the change of the scattered light intensity from the glass surface. The relationship between the ion-exchanged condition and the propagation loss was discussed.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract