• Journal of Chest Surgery
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• v.25 no.10
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• pp.1082-1086
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• 1992

Adenosquamous carcinoma of the lung is a rare disease entity and its clinical characteristics, treatment, and prognosis are poorly described. Stage I disease are amenable to operation as in bronchogenic carcinoma of non-small cell type, but stage III adenosquamous carcinoma shows highly aggressive behavior with rapid progression. We have experienced a case of stage III adenosquamous carcinoma of the lung in a 38-year-old male with a large mass in the right upper lobe with multiple metastasis in the mediastinal lymph nodes. Interestingly, all of the metastatic lymph nodes proved to be adenous component histologically. After right pneumonectomy and extensive lymph node dissection, the patient had received one cycle of chemotherapy. However, clinical signs of distant metastasis to bone and brain were discovered within 5 months postoperatively.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1417-1422
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• 2003

An electrical cascade impactor is a multistage impaction device to separate airborne particles into aerodynamic size classes using electrical method. We designed a real-time three-stage electrical low-pressure impactor, which is proper to nanometer sized environmental aerosols. Performance evaluation was carried out for stage 1 and 2. The monodisperse liquid dioctyl sebacate (DOS) particles were generated using condensation-evaporation followed by electrostatic classification using DMA (differential mobility analizer) for particles with diameters in the range of $0.04{\sim}0.8{\mu}m$. The evaluation of the electrical impactor is based on the use of two electrometers, one connected to the impaction plate of the impactor, and the other to the faraday cage as backup filter. The results showed that the experimental 50% cutoff diameters in the operation pressure were 0.53 and $0.12{\mu}m$ for stage 1 and stage 2. The effect of operation pressure on the cutoff diameter and the steepness of collection effcieicy curves is investigated.

• Progress in Superconductivity and Cryogenics
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• v.6 no.2
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• pp.40-45
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• 2004

The experimental results of the G-M (Gifford-McMahon) type pulse tube refrigerators are presented in this paper. The pulse tube refrigerator, which has no moving parts at its cold section, is attractive in obtaining higher reliability, simpler construction, and lower vibration than any other small refrigerators. The objectives of this study are to develop the design technology of the G-M type pulse tube refrigerator and acquire its application methods for replacing G-M cryocooler. As a preliminary test, the refrigeration performances of the basic, orifice, and double inlet pulse tube refrigerators were investigated. The lowest temperature obtained in the one-stage pulse tube refrigerator was 34.4K and the refrigeration capacity at the optimum operation condition was 23W at 80K. And the lowest temperature of the second stage cold head in the two-stage pulse tube refrigerators was 18.3K and the refrigeration capacities at optimum condition were 0.45W at 20K and 20W at 80K, respectively. Finally, the lowest temperature obtained in the three-stage pulse tube refrigerator was 29.8K and the refrigeration capacity at the optimum operation condition was 1.3W for 40K and 5W for 70K.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.781-789
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• 1999

Background: Pulmonary artery banding(PAB) accompanies some risks in the aspect of band complications and mortality in the second-stage operation. To assess these risks of the second-stage operation after PAB, we reviewed the surgical results of the second-stage operation in the pediatric patients who had undergone PAB in infancy. Material and Method: From May 1988 to June 1997, a total of 29 patients with preliminary PAB underwent open heart surgery. Ages ranged from 2 to 45 months(mean 20.6$\pm$9.0 months). Preoperative congestive heart failure conditions were improved after PAB(elective operation group) in 27 patients, but early second-stage procedures were required in the remaining 2 patients due to sustaining congestive heart failure(early operation group). Preoperative surgical indications included 2 double outlet right ventricles(DORV group) and 27 ventricular septal defects as the main cardiac anomaly(VSD group). Result: The mean time interval from PAB to the second-stage operation was 15.5$\pm$8.7 months(range 5 days to 45 months). One patient in the DORV group underwent intraventricular tunnel repair and modified Glenn procedure in the other. In the VSD group, the VSD was closed with a Dacron patch in all patients. Concomitant procedures included a right ventricular infundibulectomy in 4 patients and a valvectomy of the dysplastic pulmonary valve in 1 patient. At the second-stage operations, pulmonary angioplasty was required due to the stenotic banding sites in 18 patients. One patient underwent complete ligation of the main pulmonary artery with the modified Glenn procedure. The mortality at the second-stage operation was 17.2%(5 patients). Causes of death were 4 low cardiac output, and 1 autoimmune hemolytic anemia. Diagnosis with DORV and the early operative group were the risk factors for operative death in this series. There was 1 late death. Conclusion: This study revealed the second-stage operation for pulmonary artery debanding and closure of VSD in children was complicated by the correction of the acquired lesions with a significantly high incidence of morbidity and early postoperative deaths. Primary repair is recommended for isolated VSD, if possible.

• Journal of Chest Surgery
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• v.28 no.8
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• pp.807-810
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• 1995

The recommended approach for dumbell trmor is a one-stage removal by a team work of both neurosurgeons & thoracic surgeons. Recently we removed a case of dumbell tumor in a 69 years old woman with standard posterolateral thoracotomy and concomitant laminectomy as single stage operation. Postoperative course was uneventful and there were no postoperative neurologic signs.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1030-1034
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• 1993

A converter topology which is capable of four-quadrant(motoring and generation) operation is proposed for the variable speed constant frequency(hereafter referred as VSCF) power conversion scheme. The new converter topology for the VSCF power conversion scheme is made of two functional stages. One is converting stage which consists of six switches and six diodes and it interfaces a three-phase 60Hz at supply and a single-phase variable-frequency ac source. The other is the commutating stage though which each phase-winding is energized.

• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.23-34
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• 2018

This paper presents the high efficiency and high power-factor power supply for LED lighting equipment. The proposed power supply is the single-stage power structure consisted of the full-bridge diode rectifier and flyback converter, and thus the power-factor correction and output voltage regulation are performed simultaneously using only one controller IC and one power semiconductor switch. Furthermore, the proposed power supply reduces the voltage stress and switching loss of main switch using the regenerative snubber, and it improves the system efficiency using the synchronous rectifier. The applied synchronous rectifier is the new voltage-driven type and its operation and construction are simple. In this paper, the operation principle of proposed power supply is explained through the operation analyses of its power-factor correction and main power conversion parts and the operation of synchronous rectifier is described, briefly. Also, a design example of the power circuit of 40W-class prototype is shown and the operation characteristics of proposed power supply are validated through the experimental results of the implemented prototype by the designed circuit parameter.

• Journal of Korean Foot and Ankle Society
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• v.24 no.1
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• pp.25-30
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• 2020

Purpose: Generally, the treatment of ankle trimalleolar open fractures is divided into two stages: external fixation and debridement; and secondary internal fixation. On the other hand, this two-stage operation takes considerable treatment time and is challenging in procedures requiring reduction. The purpose of this study was to evaluate the radiologic and clinical results of an immediate one-stage internal fixation operation considering the wound conditions to overcome two stage operation disadvantages. Materials and Methods: From September 2009 to January 2018, 24 cases of ankle trimalleolar open fractures, who underwent immediate internal fixation and were followed up for at least one year, were studied retrospectively. The open wound was divided into the Gustilo-Anderson classification. Open reduction and internal fixation were performed on every medial and lateral malleolar fracture. On the other hand, with posterior malleolar fractures, surgical or conservative treatment was performed depending on the fragment size. The radiologic outcome was evaluated using the Burwell and Charnley criteria and American Orthopaedic Foot and Ankle Society (AOFAS) scores, and complications, such as infection and posttraumatic arthritis, were used for the clinical evaluation. Results: The wound was classified into eight cases (33.3%) of type I, 11 cases (45.8%) of type II, and five cases (20.8%) of type IIIa. The degree of reduction was anatomical, fair, and poor in 16 cases (66.7%), six cases (25.0%), and two cases (8.3%), respectively. The mean AOFAS score was 79 points, and there were complications, such as infection in three cases (12.5%) and post-traumatic arthritis in two cases (8.3%). Conclusion: Satisfactory results were obtained through immediate surgical treatment in ankle trimalleolar open fractures of types I, II, and IIIa.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.145-150
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• 2003

The national subway went under construction in 1971, and after three years of endeavor, Seoul subway line number one opened for traffic in 1974. Line number two went under construction in 1978 and it opened for traffic in 1984. With the use of safety operation for more than 20 years, the life cycle nearly came to an end. Therefore the improvements for the safety operation are unavoidable. The total system should not be affected when the new and conventional systems are overlapped, the system operation is in the initial stage, and it confronts the situation of abnormal operation. However, there is a total lack of experience in construction and improvement for the trains that are in the use of large transport and density headway. In this paper, we propose an improvement method of the subway signalling system using ATO (Automatic Train Operation control scheme) to which the latest Digital ATC is applied, and examine the first application model of ATO system.

• Journal of Chest Surgery
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• v.20 no.3
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• pp.473-482
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• 1987

The records of 65 patients with a confirmed diagnosis of primary lung cancer who underwent surgical therapy at the Department of Thoracic and Cardiovascular Surgery of the Keimyung University Hospital were analyzed during the period of 8 years and 4 months, from August, 1978 to December, 1986. The peak incidence was observed in the 5th decade of life and the mean age was 52.9 years old. Male versus female ratio was 8.3:1 Cough was the most frequent presenting symptom, 76.9% then chest discomfort, hemoptysis and dyspnea followed in order. 44.6% of the patient had 2 months of prediagnostic symptomatic period, 72.3% had 5 months, and the mean was 5.7 months. As for preoperative diagnosis, 62 of total 65 patients revealed the mass lesion on simple chest x-ray, and 56 of 65 patients on bronchoscopic biopsy, 10 of 37 patients on sputum cytology and 15 of 15 patients on computerized tomography of the chest were positive. Of the 65 patients, 35 [53.9%] had squamous cell carcinoma, 18 [27.7%] adenocarcinoma, 3 [4.6%] large cell carcinoma, and 3 [4.6%] small cell carcinoma all which was oat cell carcinoma. 83.1% of the total patient was resectable, and 34 underwent pneumonectomy and 20 lobectomy. Of these 65 operations, 29 was radical resection, 25 palliative, and 11 exploratory thoracotomy. As for clinical stagings, 23 patients were in Stage, I, another 23 in Stage II and 19 in Stage III, while 16 was in stage, I, 14 in stage ll and 35 in stage III in postoperative staging evaluation. In correlation of postoperative TNM classification and radical resection, those patients who had lung cancer of stage I [14/16] and stage II [9/13] had more radical resection. As postoperative complications, one patient had massive bleeding, two empyema, one empyema with bronchopulmonary fistula, and one cardiac herniation. Operative mortality rate was 1.5% [1 patient]. Mean duration between 1st operation and discovering recurrence in 18 patients was 12.7 months.