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Spondyloepiphyseal Dysplasia Tarda 1例
朴興一,權忠植 최신의학사 1971 最新醫學 Vol.14 No.9
This is a report of a rare case of spondyloepiphyseal dysplasia tarda in 59 year-old Korean male, whose chief complaints were short stature, and progressive back and hip pain with limited motion from 16 years old. A review of the literature is also submitted.
박흥일,이성열 ( Heung Il Park,Sung Youl Lee ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.4
N/A The study for direct synthesis of TaC carbide which was a reaction product of tantalum and carbon in the cast iron was performed. Cast iron which has hypo-eutectic composition was cast bonded in the metal mold with tantalum thin sheet of thickness of 100㎛. The contents of carbon and silicon of cast iron matrix was controlled to have constant carbon equivalent of 3.6. The chracteristics of microstructure and the formation mechanism of TaC carbide in the interfacial reaction layer in the cast iron/tantalum thin sheet heat treated isothermally at 950℃ for various time were examined. TaC carbide reaction layer was grown to the dendritic morphology in the cast iron/tantalum thin sheet interface by the isothermal heat treatment. The composition of TaC carbide was 48.5 at.% Ti∼48.6 at.% C-2.8 at.% Fe. The hardness of reaction layer was MHV 1100∼1200. The thickness of reaction layer linearly increased with increasing the total content of carbon in the cast iron matrix and isothermal heat treating time. The growth constant for TaC reaction layer was proportional to the log[C] of the matrix. The formation mechanism of TaC reaction layer at the interface of cast iron/tantalum thin sheet was proved to be the interfacial reaction.
기지내 반응법에 의한 WC 복합재료의 제조에 관한 연구 (1) - 주조접합된 주철 / 텅스텐 와이어의 계면반응층 생성기구와 조직특성 -
박흥일,김창업,허보영,이성렬,김창규 ( Heung Il Park,Chang Up Kim,Bo Young Huh,Sung Youl Lee,Chang Gyu Kim ) 한국주조공학회 1995 한국주조공학회지 Vol.15 No.3
N/A Iron-based metal matrix composites have been recently investigated for the use of inexpensive abrasion resistance material. This paper carried out to investigate the in-situ reaction effects on the microstructural characteristics and the formation mechanism of tungsten carbides in a white cast iron matrix. The specimens of Fe-3.2%C-2.8%Si alloy cast-bonded with tungsten wire were cast in the metal mold and isothermally heat treated at 950℃ up to 48 hours. The typical microstructure of heat treated specimens showed the reaction layer of WC at the interface of tungsten wire and the carbon depletion zone between the WC layer and the matrix. During the formation of WC layer, if the carbon supply is insufficient due to the decarburization of matrix or the isolation of matrix by cast-bonded W wires, the reaction layer develops coarse hexagonal crystalline WC. From the microstructural investigation, it was found that the volume of WC layer and the carbon depletion zone increased linearly with the isothermal heat treating time. This results supported that the formation rate of WC in the white cast iron matrix is controlled by the interfacial reaction with a constant reaction rate.
박흥일,김우열,배차헌,김명호 ( Heung Il Park,Woo Yeol Kim,Cha Hurn Bae,Myung Ho Kim ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.4
N/A The effects of alloying elements on the structure and mechanical properties of compacted/vermicular graphite cast irons containing copper, tin and molubdenum for producing pearlite matrix, and also containing phosphorus and boron for increasing wear resistance, were investigated. The Brinell hardness and ultimate tensile strength of the specimens with the range of compositions, [1.5% Cu-0.05% Sn-(0.2-0.4)% Mo-(0.2-0.6)% P-(0.035-0.070)% B], was found to fall within in the following range, depending on their composition; Brinell hardness of BHN 250-315, ultimate tensile strength of 28.1-40.3㎏/㎟. It was also found within this experiment that CV graphite cast irons possessing higher amount of phosphide eutectic exhibit better wear resistance, but the wear resistance became deteriorate when the area fraction of phosphide eutectics exceed more than 10%. From these experimental results, it could be concluded that the CV graphite cast iron containing 1.5% Cu, 0.05% Sn, 0.4% Mo, 0.2% P and 0.035% B showed good mechanical and wear resistance properties.
박흥일,김성규,이병우 ( Heung Il Park,Sung Gyoo Kim,Byung Woo Lee ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.4
N/A Commercial flake graphite cast iron substrate was coated with titanium powder by low pressure plasma spraying and was irradiated with a CO₂ laser to produce the wear resistant composite layer. From the experimental results of this study, it was possible to composite TiC particles on the surface layer by direct reaction between carbon existed in the cast iron matrix and titanium with thermal sprayed coating by remelting and alloying them using laser irradiation. The cooling rate of laser remelted cast iron substrate without titanium coating was about 1 × 10⁴K/s to 1 × 10⁴K/s in the order under the condition used in this study. The microstructure of alloyed layer consisted of three zones, that is, TiC particule crystallized zone (MHV 400∼500), the mixed zone of TiC particule+ledebulite (MHV 650∼900) and the ledebulite zone (MHV 500∼700). TiC particules were crystallized as a typical dendritic morphology. The secondary TiC dendrite arms were grown to the polygonized shape and were necking. And then the separated arms became cubic crystal of TiC at the slowly solidified zone. But in the rapidly solidified zone of fusion boundry, the fine granular TiC particules were grouped like grape.
CV 흑연생성에 미치는 인 (P) 및 보론 (B) 첨가의 영향
박흥일,김명호,김영홍 ( Heung Il Park,Myung Ho Kim,Young Hong Kim ) 한국주조공학회 1989 한국주조공학회지 Vol.9 No.5
N/A The effects of phosphorus and boron additions and isothermal holding time on the residual magnesium and sulfur content, and on the resultant graphite structure of cast irons were investigated. The effective recovery ratio of magnesium showed that adding phosphorus to the melt retarded the fading rate of magnesium but adding boron accelerated it. However, the residual sulfur content was found to be decreased with isothermal holding time at the beginning, and then to be increased again with holding time by resulfurization. The Mg-Equivalent for producing compacted vermicular graphite structure was found to be increased with the addition of phosphorus, whereas to be decreased with the addition of boron.