• Nuclear Engineering and Technology
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• v.33 no.2
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• pp.175-183
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• 2001

Various welding processes are now available for end cap closure of nuclear fuel element such as TG(Tungsten Inert Gas) welding, magnetic resistance welding and laser welding. Even though the resistance and TIG welding processes are widely used for manufacturing commercial fuel elements, they can not be recommended for the remote seal welding of a fuel element at a hot cell facility due to the complexity of electrode alignment, difficulity in the replacement of parts in the remote manner and a large heat input for a thin sheath. Therefore, the Nd:YAG laser system using optical fiber transmission was selected for Zircaloy-4 end cap welding inside hot cell. The laser welding apparatus was developed using a pulsed Nd:YAG laser of 500 watt average power with optical fiber transmission. The weldability of laser welding was satisfactory with respect to the microstructures and mechanical properties comparing with TIG and resistance welding. The optimum operation processes of laser welding and the optical fiber transmission system for hot cell operation in a remote manner have been developed The effects of irradiation on the properties of the laser apparatus were also being studied.

• Journal of Chest Surgery
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• v.18 no.3
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• pp.407-413
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• 1985

Ruptured aneurysms of the sinus Valsalva are relatively rare, and the incidence seems to be higher in oriental than in western countries. Five patients underwent operative treatment in Catholic Medical Center in recent 2.5 year period. Three patients were male and two patients were female, ages ranged from 20 to 54 years. Bacterial endocarditis was suspected or proved in 3 patients. In 3 patients in our series had a ruptured congenital aneurysms and in 2 patients acquired aneurysms by bacterial endocarditis. Associated cardiac lesions were common; such as aortic insufficiency in 3 patients, atrial septal defect in 2 patients, mitral stenoinsufficiency in 1 patient and tricuspid insufficiency in 1 patient. All aneurysmal ruptures of the sinus Valsalva arose from right coronary sinus and in 4 patients ruptured into right ventricle and in 1 patient into right atrium. Surgical techniques consisted of direct closure 4 in patients and closure with Dacron patch in 1 patient. And we preferred double approach, that is, through both the aorta and the involved cardiac chamber in cases in whom aortic insufficiency was present. So additional aortic valve replacement performed in 2 patients due to severe aortic insufficiency and aortic valvuloplasty performed in 1 patient. One patient who underwent direct closure of ruptured sinus Valsalva and double valve replacement died due to low cardiac output syndrome just after the operation. Operative results were relatively good in remainders.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.620-624
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• 1984

The optimal surgical management of the coarctation of the aorta associated with ventricular septal defect is still debated. Sixteen patients with the coarctation of the aorta and VSD were operated upon between November, 1980 and September 1984 at Seoul National University Hospital. They were 11 males and 5 females. All presented between 5 months and 11.5 years of age [mean= 5.5 years]. Presenting symptoms were congestive heart failure in 11 [69%], cyanosis on crying in 3 [19%], and frequent upper respiratory infection in 2 [13%]. In all cases two-stage operation was applied except one in which one stage procedure was taken. Resection and end-to-end anastomosis was used in 3, Dacron graft in 5, Gortex graft in 1, and left subclavian flap angioplasty in 4. Remaining two were missed on the operating table before correction of the coarctation of the aorta. Overall operative death in repair of the coarctation of the aorta were 3[20%]. Among the 12 survivors after repair of the coarctation of the aorta, 4 required patch closure of VSD, 2 required primary closure, 2 showed spontaneous closure [17%], one [8%] showed decrease in its size, 3 were under observation. It might be safe to approach the coarctation of aorta plus VSD with initial repair of the coarctation of the aorta without banding of main pulmonary artery and later management of VSD as usual manner in simple VSD.

• Archives of Plastic Surgery
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• v.41 no.4
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• pp.418-420
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• 2014

Congenital melanocytic nevus consists of congregations of nevomelanocytes. It is found in approximately 1% of new born infants. Congenital melanocytic nevus needs to be excised before it transforms into a malignant lesion. Many strategies have been attempted for the removal and reconstruction of the nevus. Serial excision enables wound closure to be accomplished with a shorter scar than if the original lesion was elliptically excised in a single stage and reorientation of the scar closer to the relaxed skin lines. The routine utilization of an elliptical serial excision as a standard method of closure often leads to the formation of elongated scars and waste of skin. The "Cogwheel pattern" serial excision is a new technique for reducing the size of the nevus efficiently. Reducing the final scar length, distributing the tension over many directions, and having the chance of decrease in operation numbers are ultimately achieved with the use of the "Cogwheel pattern" serial excision.

• The Journal of the Korean dental association
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• v.13 no.7
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• pp.629-632
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• 1975

The clinical investigation and operation procedure were described on the gunshot wound which involved on soft, hard palate and nasal cavity. The patient, 19 years old, female, admitted in Han Yang Medical Center with clinical diagnosis of maxillofacial injuries on Nov. 1973. No Significant signs include of airway obstruction, Oro-nasal bleeding were revealed only exception of rupture and perforation on the soft, hard palate. For closure and reduction of destructed palatal wound, operation was done in out patient dental clinic under local anesthesia by means of Langenbeck method. And to control of post-operative inflammation and reactive swelling, administration of accurate antibiotics and physical therapy were performed for 5 days after operation. On the 10th day after administration, patient was discharged with satisfactory result of operation.

• Journal of Chest Surgery
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• v.17 no.2
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• pp.197-204
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• 1984

The criss-cross, a term first used by Anderson and Ando , is a rare cardiac malformation in which the systemic and pulmonary blood streams cross at the atrioventricular level, without mixing. We have surgically experienced four cases of crossed atrioventricular connection, three concordant and one discordant, at Seoul National University Hospital from July 1982 to March 1984. The atrial situs, the atrioventriculoarterial connection, the spatial position of the ventricles, and associated cardiac anomalies were analyzed. We have performed right Blalock-Taussig shunt for case 1, modified Fontan operation for case 2, patch closure of VSD for case 3, and septation of common ventricle with primary closure of ASD for case 4. The relatively good postoperative results in these patients were gratifying and suggest that cardiac anomalies associated with this rare malformation can be successfully repaired without further risk. To our knowledge, this is the first report of surgical experience for criss-cross heart in the Korean literature.

• Journal of Chest Surgery
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• v.25 no.6
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• pp.593-597
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• 1992

The bronchopleural fistula[BPF] due to bronchial stump disruption after pneumonec-tomy has remained one of the most dreadful complications to now. The management of the BPF with empyema thoracis are still therapeutic dilemma even though a various surgical methods for the control of BPF with or without empyema thoracis. We have experienced the successful treatment of BPF & empyema thoracis with transsternal transpericardial approach. The patient was a 54 years old male who was taken left pneumonectomy at W. Medical Center at sept, 19th. 1991. He was suffered from the BPF R empyema thoracis and so was transferred to our hospital at Nov. 19th. 1991. We treated the patient with transsternal transpericardial bronchial closure for BPF, and put clagett procedure for empyema thoracis in 2 weeks. We think this kind of surgical techniques is one of the relatively simple and effective method for the control of BPF and empyema thoracis.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.647-652
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• 1998

The YGN Units 3&4 plant conditions during shutdown operation were reviewed to identified the possible even scenarios following the loss of shutdown cooling. The Thermal hydraulic analyses were performed for the five cases of RCS configurations under the worst event scenario, unavailable secondary cooling and no RCS inventory makeup, using the RELAP5/MOD3.2 code to investigate the plant behavior, From the analyses results, times to boil, times to core uncovery and times to core heat up were estimated to determined the containment closure time to prevent the uncontrolled released of fission products to atmosphere, These data provide useful information to the abnormal procedure to cope with event.

• Journal of Chest Surgery
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• v.28 no.7
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• pp.698-703
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• 1995

Dextrocardia means right-sided position of the heart in the chest irrespective of the cause. For the absolute diagnosis of the dextrocardia, the segmental analysis of heart is necessary. Once the segmental analysis of the dextrocardia is made, it is often relatively easy to identify the presence of any associated defects based on conventional methods including physical examination, EKG, echocardiography, and angiocardiography. Two cases of dextrocardia with congenital heart disease were treated surgically.A eleven - months old boy was operated under diagnosis of ASD, VSD, and bilateral SVC with mirror - image dextrocardia {I,L,I} by primary closure of ASD and VSD.A twenty-four months old girl was operated under diagnosis of ASD, VSD, and PS with corrected TGA {I,D,D} by primary closure of ASD, VSD and dilatation of pulmonary stenosis. Both of them were discharged healthily after operation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.843-849
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• 2009

The reliable operation of a swing check valve in the main feed water system of a power plant is most essential for successful shout-down process. A failure to close the valve at proper time often leads to the instability of the main feed water system, or even to an emergency stop of the power plant. In reality it is a very difficult task to monitor the behavior of a swing check valve. Furthermore it is impossible to see the motion of the valve. In this work two measurements were carried out simultaneously to determine the precise valve closure time. The dynamic pressure measurements were made at the inlet and outlet regions of the swing check valve. The transient vibration of the valve housing in the direction of water flow was also measured, which enabled the measurement of the transient vibration of the valve housing near valve closure. By comparing the results produced from these measurements the precise valve closure time could be determined. By carrying out order tracking technique using the dynamic pressure signals and pump rpm signal, the complicated dynamic problems inside the main feed water system can be more easily dealt with. This measurement scheme might be implemented in a power plant on a real-time basis without much difficulty. If this could be implemented, valuable information essential for shut-down operations can readily be passed on to the main control room. The feasibility of this implementation was demonstrated by this experimental work.