• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.6-7
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• 1981

With the improvement of living standard and educational level of the people, there is an increasing awareness about the dangers of toxic substances and lethal drugs. In addition to the above, the governmental control of these substances has led to a progressive decrease in the accidents with corrosive substances. However there are still sporadic incidences of suicidal attempts with the substances due to the unbalance between the cultural development in society and individual emotion. The problem is explained by the fact that there is a variety of corrosive agents easily available to the people due to the considerable industrial development and industrialization. Salzen(1920), Bokey(1924) were pioneers on the subject of the corrosive esophagitis and esophageal stenosis by dilatation method. Since then there had been a continuing improvement on the subject with researches on various acid(Pitkin, 1935, Carmody, 1936) and alkali (Tree, 1942, Tucker, 1951) corrosive agents, and the use of steroid (Spain, 1950) and antibiotics. Recently, early esophagoscopic examination is emphasized on the purpose of determining the way of the treatment in corrosive esophagitis patients. In order to find the effective treatment of such patients in future, the authors selected 96 corrosive esophagitis patients who were admitted and treated at the ENT department of Severance hospital from 1971 to March, 1981 to attempt a clinical study. 1. Sex incidence……male: female=1 : 1.7, Age incidence……21-30 years age group; 38 cases (39.6%). 2. Suicidal attempt……80 cases(83.3%), Accidental ingestion……16 cases (16.7%). Among those who ingested the substance accidentally, children below ten years were most numerous with nine patients. 3. Incidence acetic acid……41 cases(41.8%), lye…20 cases (20.4%), HCI……17 cases (17.3%). There was a trend of rapid rise in the incidence of acidic corrosive agents especially acetic acid. 4. Lavage……57 cases (81.1%). 5. Nasogastric tube insertion……80 cases (83.3%), No insertion……16 cases(16.7%), late admittance……10 cases, failure…4 cases, other……2 cases. 6. Tracheostomy……17 cases(17.7%), respiratory problems(75.0%), mental problems (25.0%). 7. Early endoscopy……11 cases(11.5%), within 48 hours……6 cases (54.4%). Endoscopic results; moderate mucosal ulceration…8 cases (72.7%), mild mucosal erythema……2 cases (18.2%), severe mucosal ulceration……1 cases (9.1%) and among those who took early endoscopic examination; 6 patients were confirmed mild lesion and so they were discharged after endoscopy. Average period of admittance in the cases of nasogastric tube insertion was 4 weeks. 8. Nasogastric tube indwelling period……average 11.6 days, recently our treatment trend in the corrosive esophagitis patients with nasogastric tube indwelling is determined according to the finding of early endoscopy. 9. The No. of patients who didn't given and delayed administration of steroid……7 cases(48.9%): causes; kind of drug(acid, unknown)……12 cases, late admittance……11 cases, mild case…9 cases, contraindication……7 cases, other …8 cases. 10. Management of stricture; bougienage……7 cases, feeding gastrostomy……6 cases, other surgical management……4 cases. 11. Complication……27 cases(28.1%); cardio-pulmonary……10 cases, visceral rupture……8 cases, massive bleeding……6 cases, renal failure……4 cases, other…2 cases, expire and moribund discharge…8 cases. 12. No. of follow-up case……23 cases; esophageal stricture……13 cases and site of stricture; hypopharynx……1 case, mid third of esophagus…5 cases, upper third of esophagus…3 cases, lower third of esophagus……3 cases pylorus……1 case, diffuse esophageal stenosis……1 case.

• Journal of Chest Surgery
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• v.13 no.1
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• pp.60-65
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• 1980

We have experienced 2 cases of the hunshot wound sof the chest involving cardiac injuries at department of the thoracic surgery, Capital Armed Forces General Hospital during I year from April I 1979 to Jan. 1980. In one case of two patients , he was a 22 years old man who was transported to this emergency room 4 hour 10 minutes after having gunshot wound of the left chest by helicopter. Physical examination showed small inlet in left 3rd ICS and left parasternal border, large outlet in left 8th ICS and left scapular line, no breath sound on left side and distant heart sound. chest roentgenography demonstrated marked pleural effusion in left side and mediastinum shifted to right. As soon as chest X-ray was taken, the bleeding through penetrating wound became profuse and cardiac arrest ensued. Closed chest cardiac massage was started and vigorous transfusion continued, but no effective cardiac activity could not be obtained. The patient was pronounced dead due to exsanguinating hemorrhage from wuwpected cardiac wounds. In this critically injured patient with evidence of intrathoracic hemorrhage and suspected cardiac penetration, only emergency thoracic exploration and immediate surgical control of bleeding points might offer the maximum possibility of survival. The other case was a 23 years old man who was transferred to the emergency room 4 hours 50 minutes after having kmultiple communicated fractures of sternum and linear fracture of right mandible by a missile. Examination revealed about 30% skin loss of the anterior chest wall, weak pulse of 96 beats/min., distant heart sound and decreased breath sounds bilaterally. finding on the chest X-ray films showed multiple sternal fractures, marked pericardial effusion indicating hemopericardium. So, the patient was moved immediately to the operation room where, after endotracheal tube inserted, a median sternotomy was performced. A hemorrhagic congestion of the right upper lobe and marked bulging pericardium were disclosed. The pericardium was opened anterior to right phrenic nerve and exsanguinating hemorrhage ensued from the 0.5cm lacerated wound in the auricle of right atrium. The rupture site of right atrium was occluded with non-crushing vascular clamps and then was over sewn with interrupted sutures. It was thought to be highly possible that he was alive long enough to have cardiorrhaphy because of cardiac tamponade, which prevented exsanguinating hemorrhage. He was taken closed reduction for linear fracture of right mandible 2 weeks after repair of ruptured right auricle in dental clinic. This patient's post-operative course was not eventful.

• Tuberculosis and Respiratory Diseases
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• v.39 no.4
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• pp.318-324
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• 1992

Acquired tracheobronchial stenosis has resulted from vehicular accidents, prolonged tracheal intubation, sleeve resection, tuberculosis and sarcodosis. Various modalities of therapy for the relief of such stenosis included surgery, cryotherapy, laser photoresection, and sometimes balloon dilatation. Several recent reports have described the use of self-expandable metal stents for the dilatation of stenotic areas in the tracheobronchial tree. Three patients of benign acquired tracheobronchial stenosis were treated with self-expandable metal stents, who had shown little response to several times of balloon dilatations; One patient had a tracheal stenosis caused by intubation, one a right main bronchial stenosis developed after reconstructive surgery of traumatic bronchial rupture, and the other a left main bronchial stenosis caused by longstanding endobronchial tuberculosis. We found that the using stent in benign acquired tracheobronchial stenosis can be effectively performed with alleviation of clinical symptoms and lung function. And even in longstanding localized stenosis of main bronchus without distal bronchial destruction, lung perfusion also improved.

• Journal of Radiation Protection and Research
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• v.29 no.3
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• pp.187-196
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• 2004

The health effects resulting from severe accidents of typical 1,000MWe KSNP(Korea Standard Nuclear Plant) PWR and typical 600MWe CANDU(CANada Deuterium Uranium) plants were estimated and compared. The population distribution of the site extending to 80km for both site were considered. The releaese fraction for various source term categories(STC) and core inventories were used in the estimation of the health effects risks by using the MACCS2(MELCOR Accident Consequence Code System2) code. Individuals are assumed to evacuate beyond 16km from the site. The health effects considered in this comparative study are early and cancer fatality risk, and the results are presented as CCDF(Complementary Cumulative Distribution Function) curves considering the occurrence probability of each STC's. According to the results, the early and cancer fatality risks of PHWR plants we lower than those of PWR plants. This is attributed the fact that the amount of radioactive mateials that released to the atmosphere resulting from the postulated severe accidents of PHWR plants are smaller than that of PWR plants. And, the dominating initiating event of STC that shows maximum early and cancer fatality risk is SGTR(Steam Generator Tube Rupture) for both plants. Therefore, the appropriated actions must be taken to reduce the occurrence probability and the amounts of radioactive materials released to the environment in order to protect the public for both PWR and PHWR plants.

• Korean Journal of Materials Research
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• v.11 no.6
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• pp.512-518
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• 2001

It has been well known that 6.5wt% Si steel sheets have excellent magnetic properties such as low core loss. high maximum permeability and low magnetostriction. In this work, we studied a method for producing 6.5wt% Si steel sheets using a chemical vapor deposition (CVD) method. The following is the procedure adopted in this work to produce 6.5wt% Si steel sheets; SiCl$_4$ gas is applied onto a low content-Si steel sheet placed in a tube furnace. Silicon atoms resulted from the decomposition of SiCl$_4$ are permeated through the surface of the steel sheet. Finally, by the diffusion process maintaining it under a high temperature the silicon atoms diffuse uniformly into the sheet. Through this process, 6.5wt% Si steel sheets can be obtained. The manufactured Fe-6.5wt% Si steel sheet with a thickness of 0.5mm exhibited a high frequency core loss (W$_{2}$1k/) of 8.92 W/kg. Its permeability increased from 37,100 to 53,300 at 1 tesular(T). The mechanical properties of the manufactured steel sheets were also estimated and the result showed that the workability was significantly improved by annealing in vacuum at 773k. Increased plastic deformation was also observed prior to fracture and the amount of grain boundary rupture was reduced.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2534-2546
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• 2021

Nuclear emergency preparedness and response is an essential part to ensure the safety of nuclear power plant (NPP). Key support technologies of nuclear emergency decision-making usually consist of accident diagnosis, source term estimation, accident consequence assessment, and protective action recommendation. Source term estimation is almost the most difficult part among them. For example, bad communication, incomplete information, as well as complicated accident scenario make it hard to determine the reactor status and estimate the source term timely in the Fukushima accident. Subsequently, it leads to the hard decision on how to take appropriate emergency response actions. Hence, this paper aims to develop a method for rapid source term estimation to support nuclear emergency decision making in pressurized water reactor NPP. The method aims to make our knowledge on NPP provide better support nuclear emergency. Firstly, this paper studies how to build a Bayesian network model for the NPP based on professional knowledge and engineering knowledge. This paper presents a method transforming the PRA model (event trees and fault trees) into a corresponding Bayesian network model. To solve the problem that some physical phenomena which are modeled as pivotal events in level 2 PRA, cannot find sensors associated directly with their occurrence, a weighted assignment approach based on expert assessment is proposed in this paper. Secondly, the monitoring data of NPP are provided to the Bayesian network model, the real-time status of pivotal events and initiating events can be determined based on the junction tree algorithm. Thirdly, since PRA knowledge can link the accident sequences to the possible release categories, the proposed method is capable to find the most likely release category for the candidate accidents scenarios, namely the source term. The probabilities of possible accident sequences and the source term are calculated. Finally, the prototype software is checked against several sets of accident scenario data which are generated by the simulator of AP1000-NPP, including large loss of coolant accident, loss of main feedwater, main steam line break, and steam generator tube rupture. The results show that the proposed method for rapid source term estimation under nuclear emergency decision making is promising.

• Nuclear Engineering and Technology
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• v.17 no.3
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• pp.211-215
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• 1985

The effects of temperature and strain rate on the I-SCC behaviors of Zircaloy-4 were investigated by constant load test at 30$0^{\circ}C$ and constant elongation rate test at 300, 350 and 40$0^{\circ}C$ in 3.34mg $I_2$/㎤. The results showed that I-SCC susceptibility increased as the strain rate decreased or the temperature increased. The empirical relation between the stress and the time to failure at 30$0^{\circ}C$ was given by 1/ $t_{f}$∝exp (0.3$\sigma$/$\sigma$$_{UTS}$-31.5) When the I-SCC susceptibility was expressed by the ratio of fracture energy in iodine atmosphere to that in the inert atmosphere, severe I-SCC susceptibility was found near 7.6$\times$10$^{-6}$ sec at 30$0^{\circ}C$ and the maximum point of I-SCC susceptibility tended to shift to the higher strain rate with increasing the temperature. The quasi-cleavage fracture was observed in I-SCC fracture surface. From these results, it was certain that the film repture step was involved as an important process in the I-SCC mechanism of Zircaloy-4.4.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.34-40
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• 2009

Background: The principal surgical technique for treating an abdominal aortic aneurysm since the 1960s has been the transperitoneal approach, yet there have been some recent studies that have reported improved surgical results with using the retroperitoneal approach. However, there are only limited clinical Korean studies that have, compared between the transperitoneal and retroperitoneal approaches. Material and Method: This study included 36 patients who had been diagnosed as having an aneurysm of the abdominal aorta and they were surgically treated between January 2001 and July 2007. The patients were subdivided into the retroperitoneal approach group (n=17) and the transperitoneal approach group (n=19), and they were compared in terms of the preoperative risk factors, the postoperative complications and the operative mortality. The risk factors of operative mortality risk and long-term survival for the 36 patients were assessed by the Kaplan-Meier method. Result: There were no significant differences between the groups in terms of gender, age, the underlying disease, a history of smoking, rupture of aneurysm, the preoperative symptoms, the operation time and the incidence of postoperative complications. However, the duration of postoperative fasting, the number of days of having an indwelling nasogastric tube and the length of the stay in the intensive care unit were significantly short for the retroperitoneal approach group (p<0.05). There was a 16.7% rate of operative mortality (6/36) and five of the deaths were attributed to preoperative ruptured aneurysm. On univariate analysis, a higher preoperative serum creatinine level (SCr ${\geq}$1.8 mg/dL, p=0.016) and ruptured aneurysm (p<0.001) were the significant risk factors of operative mortality. As assessed by the Kaplan-Meier method, the long-term survival was comparable between the groups and the five-year survival rate of all the patients was 57.5%. Conclusion: In the present study, a retroperitoneal approach has several advantages such as a shorter intensive care unit stay, a shorter duration of postoperative fasting and a shorter duration of an indwelling nasogastric tube. Therefore, unless there is any contraindication for a retroperitoneal approach, it could be considered as a primary surgical access for repairing an abdominal aortic aneurysm.

• Journal of Chest Surgery
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• v.32 no.4
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• pp.373-378
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• 1999

Background: Minimally invasive technique for various cardiac surgeries has become widely accepted since it has been proven to have distinct advantages for the patients. We describe here the results of our experiences of minimal incision in cardiac surgery. Material and Method: From February 1997 to November 1998, we successfully performed 31 cases of minimally invasive cardiac surgery. Male and female ratio was 17:14, and the patients age ranged from 1 to 75 years. A left parasternal incision was used in 9 patients with single vessel coronary heart disease. A direct coronary bypass grafting was done under the condition of the beating heart without cardiopulmonary bypass support(MIDCAB). Among these, one was a case of a reoperation 1 week after the first operation due to a kinked mammary artery graft. A right parasternal incision was used in one case of a redo mitral valve replacement. Mini-sternotomy was used in the remaining 21 patients. The procedures were mitral valve replacement and tricuspid annuloplasty in 6 patients, mitral valve replacement 5, double valve replacement 2, aortic valve replacement 1, removal of left atrial myxoma 1, closure of atrial septal defect 2, repair of ventricular septal defect 2, and primary closure of r ght ventricular stab wound 1. The initial 5 cases underwent a T-shaped mini-sternotomy, however, we adopted an arrow-shaped ministernotomy in the remaining cases because it provided better exposure of the aortic root and stability of the sternum after a sternal wiring. Result: The operation time, the cardiopulmonary bypass time, the aorta cross-clamping time, the mechanical ventilation time, the amount of chest tube drainage until POD#1, the chest tube indwelling time, and the duration of intensive care unit staying were in an acceptable range. There were two surgical mortalities. One was due to a rupture of the aorta cannulation site after double valve replacement on POD#1 in the mini-sternotomy case, and the other was due to a sudden ventricular arrhythmia after MIDCAB on POD#2 in the parasternal incision case. Postoperative complications were observed in 2 cases in which a cerebral embolism developed on POD#2 after a mini-sternotomy in mitral valve replacement and wound hematoma developed after a right parasternal incision in a single coronary bypass grafting. Neither mortality nor complication was directly related to the incision technique itself. Conclusion: Minimally invasive surgery using parasternal or mini-sternotomy incision can be used in cardiac surgeries since it is as safe as the standard full sternotomy incisions.

• Journal of Chest Surgery
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• v.36 no.4
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• pp.267-272
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• 2003

Background: Common treatment modalities for tracheal stenosis include conservative methods such as repeated balloon dilatation, removal of obstructive material through bronchoscopy and T-tube insertion as well as operative treatment methods. Recent advances in surgical approaches through tracheal resection and end-to-end anastomosis have been reported to give better functional and anatomical results. Material and Method: Between March 1990 and July 2002, 41 patients who received tracheal resection and end-to-end anastomosis at Asan Medical Center, University of Ulsan were studied retrospectively. Result: The causes for tracheal resection and end-to-end anastomosis included 26 cases of postintubation stenosis, 10 cases of primary tracheal tumors (3 benign, 7 malignant), 1 case of endobronchial tuberculosis, 2 cases of traumatic rupture, and 2 cases of tracheal invasion of a thyroid cancer, Of the 41 patients who received tracheal resection and reconstruction, 29 received tracheal resection and end-to-end anastomosis, and 12 received laryngotracheal anastomosis with cricoid or thyroid cartilage resection. Four of these patients received supralaryngeal release. The average length of the resected trachea was $3.6{\pm}1.0$cm. Of the 41 patients who received tracheal resection and end-to-end anastomosis, 30 (73.2%) experienced no postoperative complications, and 8 (19.5%) experienced granulation tissue growth and/or minor infections which improved after conservative management. Good or satisfactory results were therefore achieved in 92.7%. Complications included repeated granulation tissue growth in 7, wound infection in 2, anastomotic site dehiscence in 2, restenosis resulting in dyspnea on exertion in 1, and repeated postoperative aspiration requiring retracheostomy in 1. There was no early postoperative mortality. There were 3 cases of hospital death. Conclusion: In cases of proper length of tracheal lesion, excellent results were obtained after tracheal resection and end-to-end anastomosis. But, granulation tissue growth is so serious complication, it is necessary for continuous study and efforts to prevent it.