• Journal of Chest Surgery
• /
• 제28권2호
• /
• pp.213-217
• /
• 1995

Mediastinal ganglioneuroma is infrequently encountered in childhood. The posterior mediastinal ganglioneuroma which extended the contralateral thorax was very rare. A 4-year-old boy had a ganglioneuroma which involved bilateral thorax and encased the aorta and azygous vein and the ganglioneuroma was successfully extirpated by two-staged operations.; left thoracotomy first right thoracotomy 10days later.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1991년도 춘계공동학술대회 발표논문 및 초록집; 전북대학교, 전주; 26-27 Apr. 1991
• /
• pp.303-304
• /
• 1991

• 한국수소및신에너지학회논문집
• /
• 제19권3호
• /
• pp.217-225
• /
• 2008

A new micro reformer system consisted of a micro reformer, a microcombustor and a micro evaporator was studied experimentally and computationally. In order to satisfy the primary requirements for designing the microcombustor integrated with a micro evaporator, i.e. stable burning in a small confinement and maximum heat transfer through a wall, the present microcombustor is simply cylindrical to be easily fabricated but two-staged (expanding downstream) to feasibly control ignition and stable burning. Results show that the aspect ratio and wall thickness of the microcombustor substantially affect ignition and thermal characteristics. For the optimized design conditions, a premixed microflame was easily ignited in the expanded second stage combustor, moved into the smaller first stage combustor, and finally stabilized therein. A micro reformer system integrated with a modified microcombustor based on the optimized design condition was fabricated. For a typical operating condition, the designed micro reformer system produced 22.3 sccm hydrogen (3.61 W in LHV) in an overall efficiency of 12%.

• Journal of Chest Surgery
• /
• 제7권1호
• /
• pp.85-92
• /
• 1974

During the years 1959 to 1974, 99 patients with patent ductus arteriosus were admitted to National University Hospital. These includes 5 patients with additional cardiovascular and 5 patients with severe pulmonary hypertension. All were operated upon except three refused operation. In all instances, the diagnosis was made by history and physical, roentgenological and electrographic examinations. In addition, in 53 patients, special diagnostic procedures were carried out either for diagnosis or for evaluation of pulmonary hypertension and associated cardiovascular anomalies. Right cardiac catheterization was resorted to in 51 patients. In one of these patients catheterization was incorrectly interpreted [ventricular septal defect]. Retrograde aortogram was performed in two patients. In both cases the ductus itself was visualized on the x-ray film. An additional vascular anomaly, namely the persistent left superior vena cava, was confirmed by retrograde angiogram in one of them. In 5 cases the pulmonary arterial pressure was elevated well over 80 mmHg. In these instances,the operative mortality was 80% [4 out of 5 patients]. The management of patent ductus arteriosus when associated with severe pulmonary hypertension. and/or other cardiac anomalies is controversial. Opinions differ as to how to close the ductus and to repair the cardiac anomalies as well as to whether a one-staged or two-staged procedure should be resorted to. The author is of the that each case must be evaluated individually before any specific surgical treatment is ou.tlined. The literature on the subject is reviewed in this paper.

• 대한정형외과학회지
• /
• 제54권1호
• /
• pp.52-58
• /
• 2019

목적: 슬관절 전치환술 후 진균에 의한 감염은 드물지만 심각한 합병증으로 알려져 있으며 그 치료에 있어 항진균제 투여 기간이나 수술의 방법에 대해서는 이견이 있다. 이에 저자들은 인공 관절 주위 진균 감염에 대한 치료 결과 및 임상경과를 알아보고자 하였다. 대상 및 방법: 2006년부터 2017년까지 슬관절 전치환술 후 진균 감염으로 계명대학교 동산의료원에서 2단계 재치환술을 시행받은 10명의 환자를 같은 기간 비진균 인공 슬관절 주위 감염으로 치료받은 119명의 환자와 비교하였다. 임상적 평가는 2단계 재치환술에 의한 감염 조절의 실패율과 감염의 재발률 및 정주용 항생제 및 항진균제 사용기간, 2단계 재치환술 후 관절 운동 범위, 한국형 슬관절 점수(Korean knee score, KKS), 적혈구 침강속도(erythrocyte sedimentation rate, ESR), C-반응성 단백질(C-reactive protein, CRP)을 평가하였다. 결과: 진균이 동정된 군 총 10예 중 7예(70.0%)에서 감염조절의 실패를 보였고 일반 감염군 119예 중 7예(5.9%)에서 감염조절의 실패를 보였다(p=0.04). 진균이 동정된 군에서는 정주용 항진균제의 평균 사용기간은 15.3주로 일반 감염군에서의 정주용 항생제 평균 사용기간인 6.2주에 비해 9.1주 더 길었다(p<0.001). 감염 조절술 시행 전 슬관절 운동 범위는 두 군에서 모두 증가하였다(p=0.265). 최종 추시 시 KKS는 일반 감염군에서 평균 71.01점으로 나타났고 진균이 동정된 군에서 61.3점이었다(p=0.012). ESR과 CRP는 두 군에서 모두 감소하였으나 CRP만 두 군 간에 유의한 차이를 보였다(p=0.007). 결론: 슬관절 전치환술 후 발생한 인공관절 주위 진균 감염에 대한 수술적 치료는 일률적으로 양호한 결과를 보이지 않으므로 감염 조절술 시행 시 항진균제 혼합 시멘트 삽입과 재치환술 후 경구용 항진균제 사용을 고려하는 것이 필요하다.

• Geomechanics and Engineering
• /
• 제9권5호
• /
• pp.645-667
• /
• 2015

Single treatment and staged treatments in vertical wells are widely applied in sandstone and mudstone thin interbedded (SMTI) reservoir to stimulate the reservoir. The keys and difficulties of stimulating this category of formations are to avoid hydraulic fracture propagating through the interface between shale and sand as well as control the fracture height. In this paper, the cohesive zone method was utilized to build the 3-dimensional fracture dynamic propagation model in shale and sand interbedded formation based on the cohesive damage element. Staged treatments and single treatment were simulated by single fracture propagation model and double fractures propagation model respectively. Study on the changes of fracture vicinity stress field during propagation is to compare and analyze the parameters which influence the interfacial induced stresses between two different fracturing methods. As a result, we can prejudge how difficult it is that the fracture propagates along its height direction. The induced stress increases as the pumping rate increasing and it changes as a parabolic function of the fluid viscosity. The optimized pump rate is $4.8m^3/min$ and fluid viscosity is $0.1Pa{\cdot}s$ to avoid the over extending of hydraulic fracture in height direction. The simulation outcomes were applied in the field to optimize the treatment parameters and the staged treatments was suggested to get a better production than single treatment.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.849-855
• /
• 2017

우주 발사체의 운반능력을 향상시키기 위하여 고성능 다단연소사이클 엔진의 개발은 필수적이다. 그 중 연소기 헤드는 기체산화제의 유입을 위해 콘 형상으로 되어 있으며, 매니폴드는 매우 복잡한 구조를 가지고 있다. 이러한 헤드는 주조 방식이나 기계가공으로 제작되어 왔다. 기계가공의 한계나 주조재질의 특성과 재료의 한계성을 탈피하여 복잡하고 가공이 어려운 연소기 헤드의 제작 공정을 3D 금속 프린팅 공정을 이용하여 개선하는 기술을 확보하고자 한다. 현재 3D 금속 프린팅을 이용하여 주연소기에 사용할 수 있는 소재의 물성을 파악하고 프린팅 제작조건의 변화를 주는 공정개발을 통하여 더욱 낳은 물성을 확보하고, 이를 바탕으로 연소기 헤드를 제작하고, 접합공정을 개발하여 연소시험을 통해 그 성능을 입증하고 제작공정을 확립하고자 한다.

• 한국가스학회지
• /
• 제24권1호
• /
• pp.49-55
• /
• 2020

산업용 혹은 발전용 가스터빈에 사용되는 이중 콘형 예혼합 연소기의 다단 연소 특성을 이해하기 위하여 실험적연구를 수행하였다. 이를 위하여 기존에 모두 경사면에 공급되는 연료를 콘부분으로 일부 할애하는 방식으로 다단연소 방식을 구성하였으며 콘에서 분사되는 연료공급은 축방향과 콘 경사면 방향으로 하였다. 다단연소 연소특성을 이해하기 위하여 콘에서의 연료 분사 방향과 연료 분배율 변화에 대한 NOx와 CO의 배출 농도 그리고 벽면 온도분포를 측정하였다. 그 결과 총 연료에 대한 콘으로의 분배율이 3%인 경우 콘에서의 연료 분사방향에 관계없이 노즐내의 예혼합 영역에서 연료가 공기와 균일하게 혼합됨으로서 연소영역의 고온점 감소에 의하여 NOx 배출 농도가 감소된다. 그러나 콘에서 축방향으로 분사되는 연료분배율이 8%로 증가하는 경우 노즐 내부 예혼합 영역으로의 화염 역화로 인하여 NOx의 배출농도가 오히려 증가하게 된다.

• Journal of Korean Neurosurgical Society
• /
• 제29권7호
• /
• pp.929-934
• /
• 2000

Objective : The results of secondary transsphenoidal surgery(TSS) for either residual or recurring pituitary adenomas have been reported to be unfavorable. To evaluate the effectiveness of secondary TSS, we analyzed the surgical results of residual or recurred pituitary adenomas in patients who underwent secondary TSS from 1992 to 1998. Material and Methods : Among the 95 patients who underwent TSS during this period, 14(15%) received repeated TSS. Two of the 14 patients underwent three TSS. Among the 11 patients with pituitary adenomas, three had nonfunctioning tumors ; six prolachnomas ; two GH-secreting adenomas. The remaining three patieats had craniopharyngioma, pituitary abscess and hemangioendothelioma respectively. The interval between the two surgical procedures ranged from one week to 33 months(mean ; 12 months). Causes of the secondary TSS were tumor recurrence in 11 patients, intentional staged operation in three, persistent disease despite medical therapy and CSF leak after initial operation in one respectively. Treatments prior to secondary TSS were medical treatment only in eight patients. Results : During the repeated operationtss some adhesion was noted in septal mucous membrane. The sphenoid cavity was filled with fibrous tissue which correlated with the methods of reconstruction of the sellar floor at the previous operation. There was no statistically significant difference in success rate of surgery between the initial and the second TSS(86% vs 81%). The complication rate was similar between the two procedures. There was no statistically significant factors affecting the results of second TSS. Conclusion : Transsphenoidal reoperation was regarded as a suitable approach for treating recurrent pituitary adenomas in spite of some degree of operative difficulties. In patients with transsphenoidally resectable tumor residuals or recurrences confirmed by magnetic resonance imaging, remissions can be obtained with high probability, especially in secondary surgery after an staged decompression.

• Journal of Korean Neurosurgical Society
• /
• 제58권4호
• /
• pp.368-372
• /
• 2015

Objective : The occurrence of acute cerebral infection following deep brain stimulation (DBS) is currently being reported with elevation of C-reactive protein (CRP) level. The aim of the present study was to establish normal range of the magnitude and time-course of CRP increases following routine DBS procedures in the absence of clinical and laboratory signs of infection. Methods : A retrospective evaluation of serial changes of plasma CRP levels in 46 patients undergoing bilateral, two-staged DBS was performed. Because DBS was performed as a two-staged procedure involving; implantation of lead and internal pulse generator (IPG), CRP was measured preoperatively and postoperatively every 2 days until normalization of CRP (post-lead implantation day 2 and 4, post-IPG implantation day 2, 4, and 6). Results : Compared with preoperative CRP levels ($0.12{\pm}0.17mg/dL$, n=46), mean CRP levels were significantly elevated after lead insertion day 2 and 4 ($1.68{\pm}1.83mg/dL$, n=46 and $0.76{\pm}0.38mg/dL$, n=16, respectively, p<0.001). The mean CRP levels at post-lead implantation day 2 were further elevated at post-IPG implantation day 2 ($3.41{\pm}2.56mg/dL$, n=46, respectively, p<0.01). This elevation in post-IPG day 2 rapidly declined in day 4 ($1.24{\pm}1.29mg/dL$, n=46, p<0.05) and normalized to preoperative value at day 6 ($0.42{\pm}0.33mg/dL$, n=46, p>0.05). Mean CRP levels after IPG implantation were significantly higher in patients whose IPGs were implanted at post-lead day 3 than those at post-lead day 5-6 ($3.99{\pm}2.80mg/dL$, n=30, and $2.31{\pm}1.56mg/dL$, n=16, respectively, p<0.05). However, there was no difference in post-IPG day 2 and 4 between them (p>0.05). Conclusion : The mean postoperative CRP levels were highest on post-IPG insertion day 2 and decreased rapidly, returning to the normal range on post-IPG implantation day 6. The duration of post-lead implantation period influenced the magnitude of CRP elevation at post-IPG insertion day 2. Information about the normal response of CRP following DBS could help to avoid unnecessary diagnostic and therapeutic efforts.