• Journal of Chest Surgery
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• 제20권1호
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• pp.106-111
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• 1987

Twenty eight patients with atrial septal defect operated on from May, 1983, to July, 1986 at the Department of Thoracic and Cardiovascular Surgery, Chungnam National University Hospital, were analyzed retrospectively. Among the 28 patients of atrial septal defect, 8 were male and 20 were female. Their ages ranged from 4.6 years to 52.5 years old with the mean of 15.3 years. The main clinical symptoms on admission were exertional dyspnea [82%], frequent respiratory infection [75%], palpitation [54%] and easy fatigability [25%]. Electrocardiographic findings were as follows: Regular sinus rhythm [100%], RVH [54%], RBBB [25%] and first degree of A-V block [4%]. Hemodynamic studies were performed in all cases and mean pulmonary systolic arterial pressure was 34.1*11.8mmHg. and mean Qp/Qs was 2.6*0.9. All 28 patients were operated under direct vision using extracorporeal circulation. 23 cases were secundum type defect and a single hole was found in 22 cases. The associated cardiovascular anomalies were found in 11 patients: ventricular septal defect in 3, patent ductus arteriosus in 1, partial anomalous pulmonary venous drainage in 2, mitral regurgitation in 2, tricuspid regurgitation in 1, anomalous left atrial septation in 1 and valvular pulmonary stenosis in 1. The defect closed directly in 22 cases and with patches in 6 cases. Postoperative complications were wound infection, arrhythmia bleeding, intracardiac patch detachment, pneumothorax and urethral injury. But there was no operative mortality.

• Transactions on Electrical and Electronic Materials
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• 제11권1호
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• pp.42-47
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• 2010

Polymer insulating materials such as cross linked polyethylene (XLPE) are employed in electric cables used for extra high voltage. These materials can degrade due to chemical, mechanical and electric stress, possibly caused by voids, the presence of extrinsic materials and protrusions. Therefore, this study measured discharge patterns, discharge phase angle, quantity and occurrence frequency as well as changes in XLPE under different temperatures and applied voltages. To quantitatively analyze the irregular partial discharge patterns measured, the discharge patterns were examined using a statistical program. A three layer sample was fabricated, wherein the upper and lower layers were composed of non-void XLPE, while the middle layer was composed of an air void and copper particles. After heating to room temperature and $50^{\circ}C$ and $80^{\circ}C$ in silicone oil, partial discharge characteristics were studied by increasing the voltage from the inception voltage to the breakdown voltage. Partial discharge statistical analysis showed that when the K-means clustering was carried out at 9 kV to determine the void discharge characteristics, the amount discharged at low temperatures was small but when the temperature was increased to $80^{\circ}C$, the discharge amount increased to be 5.7 times more than that at room temperature because electric charge injection became easier. An analysis of the kurtosis and the skewness confirmed that positive and negative polarity had counterclockwise and clockwise clustering distribution, respectively. When 5 kV was applied to copper particles, the K-means was conducted as the temperature changed from $50^{\circ}C$ to $80^{\circ}C$. The amount of charge at a positive polarity increased 20.3% and the amount of charge at a negative polarity increased 54.9%. The clustering distribution of a positive polarity and negative polarity showed a straight line in the kurtosis and skewness analyses.

• Journal of Chest Surgery
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• 제14권1호
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• pp.49-59
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• 1981

This is one case report of surgically treated partial atrioventricular canal. The 22 year-old male patient had no definitive history of frequent respiratory infection and cyanosis in his early childhood. Since his age of 7 years, dyspnea was manifested on exertion. First appearance of congestive heart failure was at his age of 16 years old. The physical examination revealed that the neck veins were distended and heaving of precordium. A thrill was palpable on the left 3rd-4th intercostal space extending from the sternal border toward the apex and Grade IV/VI systolic ejection murmur was audible on it. Neither cyanosis nor clubbing was noted. Liver was palpable about 5 finger breadths. Chest X-ray revealed increased pulmonary vascularity and severe cardiomegaly (C-T ratio = 74%). EKG revealed LAD, clockwise rotation, LVH and trifascicular block. Echocardiogram showed paradoxical ventricular septal movement, narrowed left ventricular outflow tract and abnormal diastolic movement of the anterior leaflet of mitral valve. Right heart catheterization resulted in large left to right shunt (Qp : Qs = 5.7: 1), ASD and moderate pulfllonary hypertension. Finally, left ventriculogram revealed typical goose neck appearance of left ventrlcalar outflow tract. On Oct. 10, 1980, open heart surgery was performed. Operative findings were: 1. Large primum defect ($6{\times}5$ Cm in diameter) 2. Cleft on the anterior leaflet of mitral valve. 3. The upper portion of ventricular septum was descent but no interventricular communication. 4. Downward attachment of the atrioventricular valves on the ventricular muscular septum. 5. Medium sized secumdum defect ($2{\times}1$ Cm in diameter). The cleft was repaired with 4 interrupted sutures. The primum defect was closed with Teflon patch and the secundum defect was closed with direct suture closure. Postoperatively atrial flutter-fibrillation in EKG and Grade U/VI apical systolic murmur were found. The postoperative course was uneventful and discharged on 29th postoperative day in good general conditions.

• Archives of Reconstructive Microsurgery
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• 제21권1호
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• pp.27-33
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• 2012

We studied the results of the immediate microsurgical reconstruction of the distal digit injury with short vascular pedicled partial toe transfer. Thirteen patients with amputation or crush injury of the distal digit who underwent partial toe transfer at the authors' institute over 8-year period were reviewed. Delay between initial injury and reconstruction ranged from 1 to 9 days. All flaps were harvested on a short vascular pedicle, with anastomoses performed at a proximal interphalangeal joint level on the fingers and metacarpophalangeal joint level on the thumbs. Good to excellent cosmetic and functional results were obtained in all cases, with nearly normal-looking fingertip. The mean static two point discrimination was 10 mm. Immediate reconstruction with short vascular pedicled partial toe transfer is an excellent option for the reconstruction of the compostie defect of the distal digit.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권4호
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• pp.183-188
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• 2006

Abstract - In order to investigate the possibility of separating PD(partial discharge) and noises through the pulse analysis by use of a HFCT, pulse shapes measured by a resistive sensor and a HFCT were analyzed and adequate PA(pulse analysis) algorithms were studied. For the purpose, the HFPD detection and PA system has been developed. Also void discharges and air corona were adopted as the artificial defect and noises, respectively. As a result, it is possible to separate partial discharges and noises through the PA method using the $100kHz{\sim}20MHz$ frequency range HFCT. It is expected to apply the developed system to on-site PD measurements for the electric equipments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1691-1693
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• 2002

Acoustic partial discharge detection has been used on GIS testing for more than 10 years. Sensitivities show that most of critical defect types can be detected with a reasonable signal-to-noise ratio. The paper reports on acoustic partial discharge detection comparable to sensitive electrical PD(partial discharge) measuring method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.33-37
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• 2001

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마
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• pp.18-22
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• 2000

The partial discharge testing is widely used in insulation property measurement because it gives low stress to high voltage equipment which is undertaken tests. Therefore it is very useful method compare to previous destructive methods and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마
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• pp.29-32
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• 2000

The partial discharge testing is widely used in insulation property measurement because it gives low stress to high voltage equipment which is undertaken tests. Therefore it is very useful method compare to previous destructive methods and effective diagnosis method in power transformer that requires on-line & on-site diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and PD/HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1422-1423
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• 2007

This study deals with various neural network algorithms for the on-site partial discharge pattern recognition. For the purpose, the pattern recognition has been carried out on partial discharge data for the typical artificial defect using 9 different neural network models. In order to enhance on-site applicability, artificial defects were installed in the insulation joint box of extra-high voltage xLPE cables and partial discharges were measured by use of the metal foil sensor and a HFCT as a sensor. As the result, it is found out that the accuracy of pattern recognition could be enhanced through the application of the Sigmoid function, the Momentum algorithm and the Genetic algorism on the artificial neural networks. Although Multilayer Perceptron (MLP) algorism showed the best result among 9 neural network algorisms, it is thought that more researches on others would be needed in consideration of on-site application.