기관(氣管) 섬유종(纖維腫)의 1례(例)

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.

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.

흰쥐의 심장을 이용한 Modified Isolated Working Heart Perfusion Technique

이종국,최형호,Lee, Chong-Kook,Choi, Hyeong-Ho 대한흉부심장혈관외과학회 1980 Journal of Chest Surgery (J Chest Surg) Vol.13 No.4

We have modified an isolated perfusion rat heart model of cardiopulmonary bypass, with which we are able to screen the effects of various cardioplegic solutions and hypothermia upon the ability of the heart to survivie during and recover from period of ischemic arrest. The modified experimental model was differed from the original as follow : a heat coil chamber of atrial and aortic reservoir provided temperature control, and the perfusate was gassed with each pure oxygen and pure carbon dioxide in 95:5 ratio. The Langendorff perfusion was initiated for a 10 minute period by introducing perfusate at $37^{\circ}C.$ into the aorta from the aortic reservoir located 100 cm above the heart. The isolated perfused working rat heart model was a left heart preparation in which oxygenated perfusion medium (at $37^{\circ}C.$) entered the cannulated left atrium at a pressure of 20 cm $H_{2}O$ and was passed to the ventricle, from which it was sponeously elected(no electrical pacing) via an aortic cannula, against a hydrostatic pressure of 100cm $H_{2}O$. during this working period various indices of cardiac functin were measured. The cardiac functions were stable for over 3 hour with perfusion of Krebs-Henseleit bicarbonate buffer solution containing only glucose (11.1 mM/L). The percentage of cardiac functins were maintained about 94% on heart rate, 80.6% on peak aortic pressure, 87.7% on coronary flow and 76.3% on aortic flow rate after 3 hour of working heart perfusion at a pressure of 20 cm $H_{2}O$. We believe this preparation to be a good biochemical model for the human heart which offers many advantages including economic, speed of preparation, reproducibility, and the ability to handle large numbers.

시알론을 첨가한 탄화규소 세라믹스의 제조

이종국,박종곤,이은구,김환,Lee, J.K.,Park, J.G.,Lee, E.G.,Kim, H. 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.3

Silicon carbide with sialon was prepared by hot pressing and transient liquid-phase sintering, and the effects of sintering atmosphere and starting phases on their microstructural characteristics were investigated. The sintered SiC with Sialon composition(Y2O3, AlN, Si3N4) in argon atmosphere had high sintered density and large aspect ratio. But sintered specimens in nitrogen atmosphere showed low aspect ratio and small grian size, becuase of the retardation of phase transformation and grain growth. Addition of Y-Sialon powder to SiC also retarded the phase transformation to ${\alpha}$-SiC from ${\beta}$-SiC and densification. The SiC specimen prepared from the starting ${\beta}$-SiC powder with Sialon composition(Y2O3, AlN, Si3N4) showed the highest fracture toughness about 6.0 MPa$.$m1/2.

R2V2 하천유량계측로봇과 RTK GPS를 이용한 하천유량 및 하상변동 정밀조사

이종국,Lee, Jong-Guk 한국수자원학회 2010 물과 미래(한국수자원학회지) Vol.43 No.10

저온 열처리에 의한 Y-TZP 미세조직의 변화

이종국,김환,Lee, Jong-Kook,Kim, Hwan 한국세라믹학회 1990 한국세라믹학회지 Vol.27 No.6

The phase transformation of Y-TZP by low temperature aging treatments and its related behaviors of crack formation were investigated. The kinetics of phase transformation was greatly dependent on the amounts of Y2O3, grian size and microstructures of sintered body. The phase transformation happened to start at specimen surface and near the pore in the first place, where the change of strain energy during the phase transformation was small and the water vapor that accelerated phase transformation easily diffused.

저온 열처리에 의한 Y-TZP 분말의 등온 상전이

이종국,김환,Lee, Jong-Kook,Kim, Hwan 한국세라믹학회 1990 한국세라믹학회지 Vol.27 No.8

The ifluence of transformability and stabilized effects in tetragonal phase on the isothermal phase transformation of Y-TZP at low temperature were investigated. The transformability of Y-TZP powders were gradually increased with calcination temeprature and reached maximum at critical temperature, but when the Y-TZP powders were calcined above critical temperature, transformability of Y-TZP were gradually decreased with increasing calcination temperature. It was concluded that maximum transformability was appeared because particle size effects decreased and constrain effects increased with calcined temperature. The isothermal phase transformation during aging at 25$0^{\circ}C$ only observed in Y-TZP stabilized by constrain effects and the amounts of transformation during aging at 25$0^{\circ}C$ only observed in Y-TZP stabilized by constrain effects and the amount of transformed monoclinic phase during aging decreased with increasing constrain effects. From these results, the mechanism of isothermal phase transformation and degradation behaviors at low temperature in Y-TZP was concluded that occurred by decreasing of constrain effects due to stress relaxation at grian boundary.

PVA 흡착에 의한 안정한 콜로이드 지르코니아 졸의 합성

이종국,문기동,김환,Lee, Jong-Kook,Moon, Gi-Dong,Kim, Hwan 한국결정성장학회 1995 韓國結晶成長學會誌 Vol.5 No.2

PVA를 첨가하여 제조한 collloidal $ZrO_2$ 졸에 있어서 입자의 분산성 및 입성장에 미치는 PVA의 영향을 고찰하였다. 적정량의 PVA를 첨가하여 제조된 colloidal 졸은 균일한 흡착층의 형성으로 입자간의 응집이 효과적으로 억제된 분산이 양호한 안정된 졸이었으며 이러한 분산성은 PVA가 $ZrO_2$ 일차입자 표면에 흡착층이 형성되어 입성장을 억제하기 때문이었다. $ZrO_2$ 입자의 핵생성은 수화반응 초기에 대부분 일어났으며, 숙성 시간 에 따라 판상의 단사정상 입자가 성장하였는데 PVA의 첨가량이 증가할수록 입성장 속도와 반응수율이 감소하였다. PVA 첨가에 의해 잘 분산된 현탁액으로부터 제조된 충진체는 입자가 고르게 배열되고 응집체간에 형성된 기공이 균일하였다. A stable suspension with a colloidal $ZrO_2$ particle was prepared by an adsorption of PV A and investigated to the effects of PV A on the dispersion and particle growth within suspension. With a suspension added the optimum concentration of PYA (about 500 ppm in this study), it was shown the property of a stable sol due to the formation of adsorbed PV A layer on surface and the reduction of an agglomeration among the particles. Most of nucleation in colloidal $ZrO_2$ were occured in the early stage of hydrolysis reaction and the plate-like monoclinic $ZrO_2$ particle were grown with an aging time. The rate of particle growth and yield for a reaction were decreased with an addition of PV A. The compact prepared from well- dispersed suspension by an addition of PV A was contained the homogeneous particle arrangement and pore distribution.

ICT를 활용한 실시간 도시홍수 상황관리

이종국,Lee, Jong-Guk 한국방재협회 2016 방재저널 Vol.18 No.4

알코옥시드 가수분해법으로 합성한 이트리아 안정화 지르코니아 분말의 상안정성 및 등온상전이 특성

이종국,김영쟁,김환,Lee, Jong-Kook,Kim, Young-Jeong,Kim, Hwan 한국세라믹학회 1996 한국세라믹학회지 Vol.33 No.6

$Zr(i-OC_3H_7)_4$로부터 가수분해법으로 Y-TZP 분말을 제조한 다음, 하소온도를 달리하여 정방정상의 상온 안정화와 25$0^{\circ}C$에서의 등온상전이 거동을 고찰하였다. 그 결과, 정방정상 지르코니아 입자의 상온 안정화 효과는 하소온도가 낮을 수록, 고용된 $Y_2O_3$의 양이 클 수록 증가하였다. 또한 25$0^{\circ}C$에서 aging 하면서 Y-TZP 분말의 등온상전이를 관찰한 결과, 입자크기 효과 및 고용효과에 의해 상온 안정화된 정방정상 지르코니아 입자에서는 aging 시 등온상전이가 일어나지 않고, 반면에 구속효과에 의하여 상온 안정화된 정방정상 입자에서는 등온상전이가 활발히 진행되었다. 등온상전이로 생성된 단사정상 입자의 내부에는 많은 쌍정과 미세균열들이 존재하였는데 이는 상전이시 변형에너지를 감소시키기 위한 것으로 사료되었다. Phase stability and isothermal phase transformation during gaging at 25$0^{\circ}C$ were investigated in yttria stabilized zirconia powders prepared from hydrolysis of zirconium isopropoxide. The stability of tetragonal phase at room temperature in zirconia powder was decreased with calcination temperature but increased with the addition of yttria content. During aging at 25$0^{\circ}C$ in humid atmosphere isothermal phase transformation occurred in tetragonal zirconia powder stabilized by constraint effect not by alloying effect and grain size effect. Many twins and microcrackings were found in transformed monomlinic zirconia particles.