• 한국지구물리탐사학회:학술대회논문집
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• 2002.09a
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• pp.139-162
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• 2002

Since weak zones or geological lineaments are likely to be eroded, weak zones may develop beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. Dc resistivity surveys, however, have seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of case histories, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing at the water bottom, since the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the dc resistivity method can provide the fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio data as well as the high resolving power. The method installing electrodes at the water bottom is suitable to the detailed survey because of much higher resolving power, whereas the method floating them, especially streamer dc resistivity survey, is to the reconnaissance survey owing of very high speed of field work.

• Journal of Chest Surgery
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• v.34 no.12
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• pp.917-923
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• 2001

Background : Bronchial sleeve resection for centrally located primary lung cancer is a lung-parenchyma-sparing operation in patients whose predicted postoperative lung function is expected to diminished markedly. Because of its potential bronchial anastomotic complications, it is considered to be an alternative to pneumonectomy. However, since sleeve lobectomy yielded survival results equal to at least those of pneumonectomy, as well as better functional results, it became and accepted standard procedure for patients with lung cancer who have anatomically suitable tumors, regardless of lung function. In this study, from analyzing of occurrence rate of postoperative complication and survival rate, we wish to investigate the validity of sleeve resection for primary lung cancer. Material and Method : From January 1989 to December 1998, 45 bronchial sleeve resections were carried out in the Department of Thoracic Surgery of Seoul National University Hospital. We included 40 men and 5 women, whose ages ranged from 23 to 72 years with mean age of 57 years. Histologic type was squamous cell carcinoma in 35 patients, adenocarcinoma in 7, and adenosquamous cell carcinoma in 1 patients. Right upper lobectomy was peformed in 24 patients, left upper lobectomy in 11, left lower lobectomy in 3, right lower lobectomy in 1, right middle lobecomy and right lower lobectomy in 3, right upper lobectomy and right middle lobecomy in 2, and left pneumonectomy in 1 patient. Postoperative stage was Ib in 11, IIa in 3, IIb in 16, IIIa in 13, and IIIb in 2 patients. Result: Postoperative complications were as follows; atelectasis in 9, persistent air leakage for more than 7 days was in 7 patients, prolonged pleural effusion for more than 2 weeks in 7, pneumonia in 2, chylothorax in 1, and disruption of anastomosis in 1. Hospital mortality was in 3 patients. During follow-up period, bronchial stricture at anastomotic site were found in 7 patients under bronchoscopy, Average follow-up duration of survivals(n=42) was 35.5$\pm$29 months. All of stage I patients were survived, and 3 year survival rate of stage II and III patients were 63%, 21%, respectively. According to Nstage, all of N0 patients were survived and 3 year survival rates of Nl and N2 were 63% and 28% respectively. Conclusion: We suggest that this sleeve resection, which is technically demanding, should be considered in patients with centrally located lung cancer, because ttlis lung-saving operation is safer than pneumonectomy and is equally curative.