• Journal of Chest Surgery
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• 제12권3호
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• pp.281-288
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• Journal of Chest Surgery
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• 제12권3호
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• pp.289-296
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• 한국지반신소재학회논문집
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• 제9권3호
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• pp.87-93
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• 2010

저수지의 수위변화는 저수지 주변 강기슭 사면파괴의 주요 요인이다. 중국의 삼협댐 저수위는 홍수량 조절을 위해 145m와 175m사이에서 변화한다. 삼협댐 저수위의 정상적 운영상태에서 저수위 변동속도는 0.67m~3.0m의 범위에 있다. 마지아고 사면은 자시강의 2.1km 상류 좌측기슭에 위치한다. 자시강은 삼협지역내에 있는 양츠강의 지류이다. 2003년 저수위가 95m에서 135m로 상승한 직후, 마지아고 사면의 후면부에서 길이 20m, 폭 3~10의 균열이 발생하였다. 지금은 균열 보수 후 특별한 징후는 보이지 않고는 있으나, 이 큰 균열은 마지아고 사면의 산사태 가능성을 암시하고 있었다. 이 연구에서는 침투해석에서 얻어진 간극수압을 저수위 변동에 따른 안전율 변화를 평가하기 위해 사용되었다. 안전율 평가는 한계평형해석에 의한 사면안정해석에 의해 수행되었다. 한계평형해석에서 전단강도에 미치는 부의 간극수압 효과는 불포화 흙에 대한 프레드런드의 전단강도식을 사용하여 고려하였다. 연구결과 강기슭사면의 안전율은 저수위의 상승, 하강에 따라 감소와 증가의 경향을 보이나, 가장 위험한 상태는 저수위가 최대높이를 장기간 유지할 때인 것으로 나타났다.

• 대한기계학회논문집B
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• 제36권1호
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• pp.97-102
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• 2012

변압기 외부에 방열핀을 설치한 밀폐형 오일변압기는 절연유의 온도상승으로 인해 부피가 팽창할 경우 방열핀의 내부 부피가 확장되어 압력상승을 방지한다. 본 연구에서는 생분해도가 높아 환경친화적 이고, 인화점 및 발화점이 높아 화재의 위험도가 낮은 식물성 절연유를 이용하여 당사 풍력발전기에 적용할 밀폐형 오일변압기를 개발하였다. 열 유동 전산수치해석 기법을 이용하여 식물성 절연유 냉각성능을 광유 및 실리콘유와 비교 분석 하였으며, 밀폐형 오일변압기의 개발을 위하여 변압기 중신부의 열적 안전성을 확보하고 절연유의 온도변화에 따른 내부 압력변화에 대응이 가능한 팽창형 방열핀을 개발하였다. 추가로 온도상승시험을 통하여 수치해석 결과와 시험 결과를 비교 분석 하였으며, 식물성 절연유를 사용한 밀폐형 오일 변압기의 설계 고려사항을 도출하였다.

• Korean Chemical Engineering Research
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• 제57권6호
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• pp.790-803
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• 2019

디옥틸테레프탈산(DOTP) 제조공정은 분말형태의 테레프탈산(PTA) 주원료와 옥탄올(Octanol)의 에스테르화 반응을 통해 플라스틱 가소제를 생산하는 공정이다. 본 연구에서는 이 공정의 반응기 내에 가연성 용제나 유증기가 존재하고 있는 상태에서 분말형태로 맨홀에 직접 투입하는 테레프탈산의 분진폭발 특성에 관하여 고찰하였다. 분진의 입경과 입도분포 분진특성 실험을 하였고, 화재 폭발특성과 발화온도를 추정하기 위한 분진의 열분해 특성을 조사하였다. 또한 폭발민감도를 평가하기 위한 최소점화에너지 실험을 실시하였다. 실험결과 테레프탈산의 분체 특성은 평균입경이 $143.433{\mu}m$으로 나타났다. 이러한 입경과 입도분포 조건에서 실시한 열분석으로부터 분진의 발화온도는 약 $253^{\circ}C$로 나타났다. 테레프탈산의 폭발민감도를 알기 위해 조사한 폭발하한 농도(LEL)는 $50g/m^3$으로 측정되었다. 폭발민감도를 나타내는 최소점화에너지(MIE)는 (10 < MIE < 300) mJ로 나타났으며, 점화 확률에 기반하여 추산한 최소점화에너지 추정값(Es)은 210 mJ로서 충분한 점화원이 있는 경우 폭발할 수 있음을 알 수 있었다. 또한 폭발피해 예측에 필요한 폭발강도 특성을 조사한 결과, 테레프탈산 분진의 최대폭발압력($P_{max}$), 최대폭발압력상승속도[$({\frac{dP}{dt}})_{max}$]는 각각 7.1 bar, 511 bar/s로 나타났다. 분진폭발지수(Kst)는 139 mbar/s로 분진폭발등급 St 1에 해당되는 것으로 나타났다.

• 해양환경안전학회지
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• 제27권5호
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• pp.683-690
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• 2021

선박 기관실 통풍 설계조건 및 계산 기준에 관한 국제 표준(ISO 8861)을 만족해야 하는 선박 기관구역의 환기시스템은 일반적으로 내연기관에 필요한 연소공기의 공급과 기관구역에서 발생한 열원을 제거하기 위해 설치되며 화재감지기가 포함된 환기시스템의 응답지연은 구역 내부에 형성된 기류와 화재감지기의 설치 위치에 영향을 받는다. 어선에서 발생하는 화재는 상선과 비교하여 인명피해 가능성이 높으므로 화재 조기 감지가 무엇보다 중요하다. 따라서 본 논문에서는 어선에 설치되는 화재 감지기의 초기 화재감지 응답속도 향상과 설치된 감지기의 감도 유지를 위해 기관구역 내부에서 발생한 정량적 연기량에 따른 공기 유동장, 내연기관 연소 공기량 및 기관 구역 내부 압력을 변수로 연기 거동 시뮬레이션이 가능한 해석모델을 구성하여 선박 기관구역 내부의 연기 거동을 시뮬레이션하였다. 시뮬레이션 결과를 통해 기관실 내부 압력을 감소시키고 연기커튼 설치를 통해 공기 유동장에서의 유속을 감소시키고 와류를 증가시키면 연기 성분의 천장 상승이 가속화되어 연기감지기 응답속도 및 환기시스템이 개선될 수 있을 것으로 해석되었다.

• 한국방재안전학회논문집
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• 제16권4호
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• pp.19-31
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• 2023

미래 기후 시나리오에 따르면 우리나라 자연재해의 주요 요인인 태풍의 강도는 강해질 것으로 전망된다. 태풍 강도 증가는 내습 파고 상승으로 이어져 주거, 산업, 관광 등의 용도로 인구 및 건물 밀집도가 높은 연안 지역의 대규모 피해발생 가능성이 높은 상황이다. 따라서 본 연구에서는 동해 해양기상부이 관측자료를 분석하여 최대 유의파고가 나타난 태풍 마이삭(202009) 내습 기간에 대해 파랑추산 수치모형실험을 수행하였다. 파랑추산실험 경계조건은 JMA-MSM의 바람장과 SSP5-8.5 미래 기후 시나리오의 태풍 중심기압 감소율을 적용한 바람장을 사용하였다. 파랑추산실험 결과 SSP5-8.5 시나리오에서 속초항 방파제 전면에서의 파고는 4.06 m에서 4.68 m로 15.27% 증가하였다. 또한, 심해설계파 147-2 격자점 위치에서의 재현빈도는 최소 2배 이상 증가하는 것으로 산출되어, 현재 해안구조물 설계 시 관행적으로 적용하는 50년 재현빈도 심해설계파에 대한 제고가 필요하다.

• The Korean Journal of Pain
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• 제1권1호
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• pp.20-27
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• 1988

Continuous cervical epidural anesthesia with two different concentrations of bupivacaine had been performed in 43 cases for surgery of upper extremity and cervical spine. After the initial dose of 0.33% bupivacaine 15ml to Group I(n=22) and 0.5% bupivacaine 15ml to Group II(n=21) was injected respectively, we observed the circulatory and pulmonary functions to be changed, and evaluated the duration of those analgesic action. The number of spinal segment to be affected and the complications were checked. Statistical significance of changes after the initial dose in both groups was determined by student's t-test. All values are impresed as mean$\pm$1S.D.. The results were as follows: 1) Circulatory functions; Systolic B.P. and Pulse rate were decreased by 10~15torr and 5~6 beats per minute respectively between 10~30 minutes following the initial dose, which were statistically significant in both groups. 2) Pulmonary functions; The diminution of minute volume showed to 20% and a rise of $PaCO_2$ level to 5~6 torr respectively between 30~60 minutes following the initial dose, which were statistically significant in both groups. There were no significant changes in self respiration and respiratory rate in both groups. 3) The duration of analgesic action was $72.3{\pm}25.7$(min) in Group I and $83.5{\pm}28.5$(min) in Group II which was not statistically significant between two groups, and the number of affected spinal segment at ore hour following the Anesthusia was $8.7{\pm}2.0$ in Group I and $10.5{\pm}2.4$ in Group II which was statistically significant between two groups. 4) Complications; a. Hypotension(below 80torr in systolic pressure) was appeared in 5% of all patients. b. Bradycardia(below 60 beats per minutes) was appeared in 25% of all patients. c. Inadvertent dural puncture was developed in only one patient, In conclusion, the 0.33% bupivacaine as well as 0.5% bupivacaine were enough for those analgesic effect in the above mentioned surgery even though the duration of analgesic action was about 10 minutes shorter in Group I than that of Group II. The cardiopulmonary function was clinically rather stable in Group I than that of Group II. Therefore we thought 0.33% bupivacaine was satisfactory for the clinical practicality in the cervical epidural anesthesia.

• 상하수도학회지
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• 제34권6호
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• pp.393-402
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• 2020

In the membrane process, it is important to improve water treatment efficiency to ensure water quality and minimize membrane fouling. In this study, a pilot study of membrane process using reservoir water was conducted for a long time to secure high flux operation technology capable of responding to influent turbidity changes. The raw water and DAF(Dissolved Air Flotation) treated water were used for influent water of membrane to analyze the effect of water quality on the TMP (Trans Membrane Pressure) and to optimize the membrane operation. When the membrane flux were operated at 70 LMH and 80 LMH under stable water quality conditions with an inlet turbidity of 10 NTU or less, the TMP increase rates were 0.28 and 0.24 kPa/d, respectively, with minor difference. When the membrane with high flux of 80 LMH was operated for a long time under inlet turbidity of 10 NTU or more, the TMP increase rate showed the maximum of 43.5 kPa/d. However, when the CEB(Chemically Enhanced Backwash) cycle was changed from 7 to 1 day, it was confirmed that the TMP increase rate was stable to 0.23 kPa/d. As a result of applying pre-treatment process(DAF) on unstability water quality conditions, it was confirmed that the TMP rise rates differed by 0.17 and 0.64 kPa/d according to the optimization of the coagulant injection. When combined with coagulation pretreatment, it was thought that the balance with the membrane process was more important than the emphasis on efficiency of the pretreatment process. It was considered that stable TMP can be maintained by optimizing the cleaning conditions when the stable or unstable water quality even in the high flux operation on membrane process.

• Geomechanics and Engineering
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• 제37권6호
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• pp.599-614
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• 2024

To evaluate the safety status of deteriorated segments in a submarine shield tunnel during its service life, a seepage model was established based on a cross-sea shield tunnel project. This model was used to study the migration patterns of erosive ions within the shield segments. Based on these laws, the degree of deterioration of the segments was determined. Using the derived analytical solution, the internal forces within the segments were calculated. Lastly, by applying the formula for calculating safety factors, the variation trends in the safety factors of segments with different degrees of deterioration were obtained. The findings demonstrate that corrosive seawater presents the evolution characteristics of continuous seepage from the outside to the inside of the tunnel. The nearby seepage field shows locally concentrated characteristics when there is leakage at the joint, which causes the seepage field's depth and scope to significantly increase. The chlorine ion content decreases gradually with the increase of the distance from the outer surface of the tunnel. The penetration of erosion ions in the segment is facilitated by the presence of water pressure. The ion content of the entire ring segment lining structure is related in the following order: vault < haunch < springing. The difference in the segment's rate of increase in chlorine ion content decreases as service time increases. Based on the analytical solution calculation, the segment's safety factor drops more when the joint leaks than when its intact, and the change rate between the two states exhibits a general downward trend. The safety factor shows a similar change rule at different water depths and continuously decreases at the same segment position as the water depth increases. The three phases of "sudden drop-rise-stability" are represented by a "spoon-shaped" change rule on the safety factor's change curve. The issue of the poor applicability of indicators in earlier studies is resolved by the analytical solution, which only requires determining the loss degree of the segment lining's effective bearing thickness to calculate the safety factor of any cross-section of the shield tunnel. The analytical solution's computation results, however, have some safety margins and are cautious. The process of establishing the evaluation model indicates that the secondary lining made of molded concrete can also have its safety status assessed using the analytical solution. It is very important for the safe operation of the tunnel and the safety of people's property and has a wide range of applications.