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Seoul, South Korea

Lee J.G.,Korea Atomic Energy Research Institute | Hong S.M.,Korea Atomic Energy Research Institute | Park J.J.,Korea Atomic Energy Research Institute | Lee M.K.,Korea Atomic Energy Research Institute | And 3 more authors.
Materials Characterization | Year: 2010

An experiment was conducted to produce nanostructured TiO2+HA composite powders by high energy ball-milling (HEBM). Simply mixed TiO 2+HA powders were ball-milled for 1-20 min in a high energy planetary ball mill at KAERI in Republic of Korea. This mill was specially designed to apply an ultra high energy to the powders, up to 690 m/s2 or 70G. Rotation speeds of the disk and the jars were 1000 and 2400 rpm, respectively, producing a milling energy of 590 m/s2 (60 G). The phases present in both the starting powders and the ball-milled ones were determined by means of X-ray diffraction. Quantitative chemical analyses were also performed using an energy dispersive spectroscope (EDS) in an SEM. The ball-milled powders were mounted with a low viscosity epoxy resin to observe cross-sections. It was observed that HA and TiO2 phases were homogeneously distributed with a grain size of 10-20 nm, demonstrating that the TiO2 and HA powders were effectively refined to the very fine nanostructure during HEBM. Source


Kim H.S.,Kongju National University | Lee J.G.,Korea Atomic Energy Research Institute | Rhee C.K.,Korea Atomic Energy Research Institute | Joo U.H.,BioMaterials Korea Inc. | Hong S.J.,Kongju National University
Materials Transactions | Year: 2010

In this study, sintered bodies of TiO2 nanopowders were fabricated by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering and then, their density and shrinkage were investigated. The optimum mixing conditions of polyvinyl alcohol, water, and TiO2 nanopowder for compaction were found to be 2-3 mass% PVA, 15-20 mass% water, and 70-85 mass% of TiO2 powder in the sintered bulks. High pressure and rapid compaction using magnetic pulsed compaction (MPC) enhanced the density with the increasing MPC pressure up to 0.7 GPa and significantly reduced the shrinkage rate (about 15% in this case) of the sintered bulks compared to the general process (about 18%). ©2010 The Japan Institute of Metals. Source


Park J.-J.,Yonsei University | Park J.-J.,Korea Testing Laboratory | Joo U.-H.,BioMaterials Korea Inc. | Kim K.-M.,Yonsei University | Kim K.-N.,Yonsei University
International Journal of Materials Research | Year: 2012

The aim of this study was to develop Au-Pt-Pd-Si alloys with metal-resin bonding properties optimized for dental restorations. The amount of silicon added ranged from 0.00-0.54 wt.% . The Au-Pt-Pd-Si alloys were manufactured using an arc melting furnace. They were homogenized at 800°C in air and cold rolled to a 1 mm thickness. The changes in the surface morphology and oxide layer formation were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy, electron probe microanalysis and X-ray photoelectron spectroscopy before and after oxidation treatment. The mechanical properties of the alloys were evaluated using micro-hardness and shear bonding tests. The surface oxide layer was mostly composed of silicon dioxide and metallic gold. The microhardness of the Au-Pt-Pd-Si alloys increased as a function of the silicon concentration. The shear bonding strength was significantly higher (9.30 MPa) at 0.54 wt.% silicon (p < 0.05). © 2012 Carl Hanser Verlag GmbH & Co. KG. Source


Patent
Biomaterials Korea Inc. | Date: 2014-06-19

A maxillary skeletal expander includes a pair of bodies, an extending screw adjusting a space between the pair of bodies, guide rails having both sides inserted into the pair of bodies and guiding a movement of the bodies, a key hole integrally formed with the extending screw, screw insertion portions integrally formed with the bodies and having screw insertion holes guiding mini-screws implanted to an upper jaw, arms having one end fixed to the bodies and the other end extending toward teeth, and a teeth fixing part integrally formed with the arms and fixed to teeth of a patient.


Moon S.-K.,Yonsei University | Kim C.-K.,Yonsei University | Joo U.-H.,BioMaterials Korea Inc. | Oh K.-T.,BioMaterials Korea Inc. | Kim K.-N.,Yonsei University
International Journal of Materials Research | Year: 2012

This study examined the biocompatibility of the micro-nanoporous layer formed on a titanium-silver (Ti-Ag) alloy. The porous layer was formed by grit-blasting and anodic oxidation. The surface of the porous layer was rougher and more hydrophilic compared to a simple machined specimen and the expressions of bone-related genes were greater for cells grown on the porous layer compared to that of cells cultured on a control surface. Also the bone-to-plate contact rate in vivo test was significantly improved for porous layer plate compare to simple machined specimen (P < 0.05). The porous layer on Ti-Ag alloy enhanced the peri-implant bone formation at the early healing stage and it was believed that this porous layer on the Ti-Ag alloy will be suitable for dental implant applications. © 2012 Carl Hanser Verlag, Munich, Germany. Source

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