Papers by Author: Seiji Yamaguchi

Abstract: Apatite nuclei were precipitated in the pores of the porous polyethylene matrix in 2.0SBF. Apatite was induced by the apatite nuclei inside the pores and on the surface of the composite and grew to the surface of the composite by a soak in 1.0SBF. The formed apatite showed high adhesive strength to the composite probably due to a mechanical interlocking effect between the matrix and the apatite.

Abstract: Resist pattern was developed on a cathode for EPD and a polytetrafluoroethylene (PTFE) film was set on the cathode. Then EPD was performed with a suspension of hydroxyapatite (HA) nuclei in ethanol. In this process, HA nuclei were deposited on a porous PTFE film so as to transcribe the resist pattern. The substrate was soaked in simulated body fluid (SBF) and HA was selectively induced on HA nuclei. As a result, HA pattern whose resolution was as high as the resist pattern was fabficated.

Abstract: Apatite micropattern was fabricated by a combination of biomimetic process and transcription of resist pattern. We optimized some fabrication conditions such as the height of resist pattern, temperature, concentrations and pH of simulated body fluid(SBF). Consequently, we successfully obtained apatite micropattern widely and homogeneously on a substrate in a short fabrication period.

Abstract: Apatite pattern was prepared by electrophoretic deposition (EPD) transcribing resist pattern. A porous polytetrafluoroethylene (PTFE) film was used as a substrate and attached on a cathode. The cathode for EPD was stainless plate with resist pattern. EPD was performed with a suspension of wollastonite particles in acetone and wollastonite particles were deposited on the substrate in the form of the resist pattern. When the wollastonite-deposited substrate was soaked in simulated body fluid (SBF), apatite was induced and then replaced wollastonite at the wollastonite deposited region on the substrate. As a result, apatite was formed in the pattern that traced the resist pattern. The minimum line width of the apatite pattern was about 100 µm.

Abstract: By electrophoretic deposition, wollastonite particles were deposited in pores of porous ultrahigh molecular weight polyethylene (UHMWPE). The UHMWPE-wollastonite composite thus fabricated was soaked in a simulated body fluid. As a result, apatite was formed inside the pores as well as on the surface of the UHMWPE-wollastonite composite. The formed apatite showed high adhesive strength to the composite.

Abstract: Most of the ion implanter is large scale, high acceleration voltage and expensive. For research and development, such a huge implanter is not required. Our motivation is to make desktop type ion implanter for SiC device. We report the fabrication of a compact 100 kV ion implanter. In order to miniaturize the equipment, an ion source, an accelerator tube and a main chamber were vertically arranged. We implanted Argon (Ar) and Nitrogen (N) ions to 6H-SiC substrate and the implanted 6H-SiC substrates were characterized by Fourier Transform Infrared Spectrometer (FTIR), Rutherford Backscattering Spectrometry (RBS) and Secondary Ion Mass Spectrometry (SIMS). In this report, concept of desktop ion implanter, evaluation of implanted substrate and its device application are presented. In order to characterize capability, with using the newly made compact ion implanter, it was possible to make implantation on SiC to get amorphous layer suitable for deices.

Abstract: Electrophoretic deposition (EPD) was applied to forming apatite pattern. A pattern of holes was formed on a polytetrafluoroethylene (PTFE) board and a porous PTFE film was superposed on the PTFE board. Wollastonite particles were deposited on the PTFE film by EPD and wollastonite pattern was obtained. Then apatite was induced at the wollastonite deposited region by soaking in a simulated body fluid.

Abstract: Alumina is excellent biomaterial and used in hip prostheses, dental implants and so on. Wollastonite particles were deposited in pores of porous alumina by electrophoretic deposition and an alumina-wollastonite composite was produced. Apatite was formed both inside the pores and on the surface of the composite of the alumina-wollastonite composite by soaking in a simulated body fluid. It was indicated that the deposited wollastonite particles induced the apatite formation. Novel composite material with both excellent mechanical properties and high bioactivity was developed.