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외상성(外傷性) 기관지(氣管支) 파열(破裂) - 1례(例) 보고(報告) -
이종국,이성구,이성행,Lee, Chong Kook,Lee, Sung Koo,Lee, Sung Haing 대한흉부심장혈관외과학회 1976 Journal of Chest Surgery (J Chest Surg) Vol.9 No.1
Rupture of a bronchus is an unusual result of nonpenetrating trauma to the chest. This case was a 19 year old male who was a worker in the mine. The patient had sustained a compression chest injury without external wound or rib fracture. At five days after trauma, he was suffered from dyspnea and the symptom was progressively increased. Two weeks after the chest trauma, a diagnosis of left main bronchial obstruction due to traumatic bronchial rupture was made by means of bronchoscopy and bronchography. He was operated upon. The left lung was completely atelectatic and the left main bronchus was found to be transected at the level of 3cm from carina. End-to-end anastomosis of the bronchus was performed and the left lung was aerated very well. postoperative course was uneventful.
이종국,이성구,이성행,Lee, Chong Kook,Lee, Sung Koo,Lee, Sung Haing 대한흉부심장혈관외과학회 1976 Journal of Chest Surgery (J Chest Surg) Vol.9 No.1
Primary tumors of trachea are rather uncommon, and few cases of direct surgical excision were reported in the literature. Recently we had the opportunity to see a patient with a benign obstructing tumor of the trachea which was confirmed as fibroma. The patient has complained of intermittent dyspnea, especially during inspiratory phase, dry cough and wheezing of a strident character for last 8 years. Bronchoscopy or bronchography were not attempted because of severe dyspnea. Trachea tomogram revealed oval mass at the terminal trachea. The right posterolateral thoracotomy was performed. Tumor, $2.5{\times}1.7cm$ in size, was located at terminal trachea and removed through right lateral tracheotomy without difficulty. Postoperatively all the symptoms and signs disappeared.
Yttria를 도핑한 세리아 안정화 지르코니아 세라믹스의 미세구조
이종국,강현희,서동석,이은구,김환,Lee, J.K.,Kang, H.H.,Seo, D.S.,Lee, E.G.,Kim, H. 한국재료학회 1999 한국재료학회지 Vol.9 No.8
세리아 안정화 지르코니아 성형체내에 이트리아를 침적법으로 도핑시켜 미세구조를 관철하였다. 도핑된 이트리아의 양과 열처리 조건을 제어하여 입계가 변형된 불규칙 입자형상의 미세구조를 형성시켰으며, 이때 입자형상의 불규칙 정도는 첨가된 이트리아의 양에 비례하였다. 0.2M 농도의 Y(NO$_3$)$_3$.6$H_2O$의 수용액에 재침적하여 1$650^{\circ}C$에서 2시간 열처리한 시편의 미세구조는 표면부와 내부 모두에서 불규칙 입자형상을 나타내었으며, 입자의 불규칙도도 가장 큰 것으로 나타났다. 가압소결을 행한 결과 입계가 불규칙하게 변화된 미세구조가 창출됨과 동시에 평균입자 크기가 0.3$\mu\textrm{m}$ 가량인 미세한 소결체를 제조할 수 있었으며, 상분석 결과 대부분 정방정상을 유지하고 있었다. 불규칙 입자형상의 미세구조를 가진 시편의 파괴인성값은, 정상적인 입자형상을 갖는 시편에서의 압흔 균열 크기로부터 비교 유추한 결과 17.6MPa.m(sup)1/2 이상인 것으로 나타났다. Yttia-doped ceria-stabilized ziconia polycrystals(Ce-TZP) was prepared by dipping method and its microstructure was investigated. By controlling doped-yttria content and annealing condition, yttria-doped Ce-TZP showed the microstructure with irregular grain shape and undulated grain boundary. Irregularity of grain shape increased with the amount of yttria doped, and severe undulated grain boundary was observed mainly at the surface region. In the case of yttria-doped Ce-TZP annealed at 1$650^{\circ}C$ for 2h after two dipping times into yttrium nitrate solution of 0.2M, it showed irregular grain shape both at the surface and at the interior region as well as the most severe irregularity. Hot pressed specimen had mean grain size of 0.3$\mu\textrm{m}$ and undulated grain boundary. All specimens with irregular grain shape were retained the tetragonal phase. The fracture toughness of yttria-doped Ce-TZP with irregular grain shape was over the value of 17.6MPa.m(sup)1/2.
천연 및 인공원료로부터 제조한 생체친화형 하이드록시아파타이트 세라믹스
이종국,고영화,이난희,Lee, Jong-Kook,Ko, Young-Hwa,Lee, Nan-Hee 한국재료학회 2012 한국재료학회지 Vol.22 No.6
Hydroxyapatite (HA) is well known as a biocompatible and bioactive material. HA has been practically applied as bone graft materials in a range of medical and dental fields. In this study, two types of dense hydroxyapatite ceramics were prepared from natural bones and synthetic materials. The biocompatibility of HA ceramics for supporting osteoblast cell growth and cytotoxicity using an in vitro MG-63 cell line model were respectively evaluated. Artificial hydroxyapatite shows relative density of 93% with 1-2 ${\mu}m$ after sintering, but a hydroxyapatite compact derived from bovine bone has low sintered density of 85% with a small content of MgO. Irrespective of the starting raw materials, both types of sintered hydroxyapatite displayed similar biocompatibility in the tests. FE-SEM observations showed that most MG-63 cells had a stellar shape and formed an intercellular matrix containing fibers on sintered HA. The cells were well attached and grown over the HA surface, indicating that there was no toxicity.
이종국,최남규,서동석,Lee Jong-Kook,Choi Nam-Kyu,Seo Dong-Seok 한국재료학회 2005 한국재료학회지 Vol.15 No.5
Silver nanoparticles were synthesized by chemical reduction method from aqueous silver nitrate solution ana hydrazine as a reduction agent. The morphology, particle size and shape were dependent on the mixing method, reaction temperature and time, molar ratio of hydrazine and silver nitrate, the kind of surfactant, and the addition of surfactant. The stability of the colloidal silver was achieved by the adsorption of surfactant molecules onto the particle. Silver nanoparticles have a characteristic absorption maximum at 430 nm under UV irradiation. It was found that the colloid was nanometer m size and formed very stable dispersion of silver. The Ag nanoparticles obtained showed the spherical shape with the size range of 10-30 nm.
실버 페이스트의 치밀화 및 비저항에 미치는 소결조제와 프릿의 영향
이종국,박성현,양권승,Lee, Jong-Kook,Park, Sung-Hyun,Yang, Gwon-Seung 한국재료학회 2008 한국재료학회지 Vol.18 No.5
The effect of sintering aids and glass-frit on the densification and resistivity of silver paste was investigated in an effort to enhance the sintered density and electrical conductivity of the silver electrode. To prepare Pb-free silver paste for use at low sintering temperatures, two commercial silver powders ($0.8\;{\mu}m$ and $1.6\;{\mu}m$ in size) and 5wt.% lab-synthesized nanoparticles (30-50 nm in size) as a sintering aids were mixed with 3 wt.% or 6 wt.% of glass frit ($Bi_2O_3$-based) using a solvent and three roll mills. Thick films from the silver paste were prepared by means of screen printing on an alumina substrate followed by sintering at $450^{\circ}C$ to $550^{\circ}C$ for 15 min. Silver thick films from the paste with bimodal particles showed a high packing density, high densification during sintering and low resistivity compared to films created using monomodal particles. Silver nanoparticles as a sintering aid enhanced the densification of commercial silver powder at a low sintering temperature and induced low resistivity in the silver thick film. The glass frit also enhanced the densification of the films through liquid phase sintering; however, the optimum content of glass frit is necessary to ensure that a dense microstructure and low resistivity are obtained, as excessive glass-frit can provoke low conductivity due to the interconnection of the glass phase with the high resistivity between the silver particles.