• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.283-284
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• 2006

The ship performs heat exchange using seawater to keep main engine and auxiliary machinery at optimum temperature. In heat exchanger, refrigerant located outside of copper tube is cooled by seawater flowing through inside of copper tube. On the other hand, seawater erosion and corrosion nay occasionally cause the corrosion of the copper tube in A/C(Air Conditioner) condenser. This corrosion of copper tube makes seawater and refrigerant mixed, seriously damaging A/C system. In this study, accordingly, the exact ive mechanism of the corrosion on the condenser entailing serious problems occasional is investigated through the electrochemical polarization experiments on the condenser's component materials. According to the experiments, the corrosive procedures on the copper tube was verified by the fact that passive film of the copper tube surface which is destroyed by the pressure of sucked seawater, is damaged by the corrosive ingredients in the seawater.

• Journal of Chest Surgery
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• 제25권2호
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• pp.183-187
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• 1992

Reconstructive surgery for corrosive esophageal stricture was performed in 392 patients at National Medical Center from 1959 to 1990 Between Jan. 1971 and Dec. 1990, 23 cases were experienced stenotic anastoma of neck after reconstructive surgery for corrosive esophageal stricture. The major procedure of esophageal reconstruction was colon interposition without resection of the strictured esophagus except jejunal interposition in 1 case. There were 12 males % 11 females, and mean age was forty years. The caustic materials were 16[70%] alkali and 7[30%] acid. Half of the cases had hypopharyngeal injury. After reconstructed surgery, dysphagia was developed immediate in 65%, from 2 months to 5 months in 31%, and from years in 4%[1 case]. The complications were anastomatic leakage in 13 cases, anastomatic stenosis in 8 cases, graft gangrene in 1 case, and cancer development in 1 case. The therapeutic procedures were end-to-end anstomolis & partial resection of stenotic anastoma in 18 cases, bourgination in 2 cases, and coin interposition with graft removal in 3 cases. The therapeutic results were excellent in 16 cases, mild discomfort in 3 cases, poor in 3 cases, and death in 1 cases.

• Journal of Chest Surgery
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• 제23권1호
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• pp.107-114
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• 1990

During a ten-year period from August, 1978 to September, 1989 45 patients with benign esophageal stricture were surgically evaluated. The results are as follows; l. Out of 45 patients, there were 26 males and 19 females ranging from 2 to 70 years of age with a mean of 31.9 years. 2. The most common cause of benign esophageal stricture was corrosive burn due to caustic agents[40 cases, 88.9 %]. Corrosive agents were 15 cases of lye, 22 cases of acid and 3 cases of other agents. Other causes were two cases of esophageal web and each one case of previous surgical result, inflammation and idiopathic mediastinal fibrosis respectively. 3. The most frequent stricture site was whole esophagus as 21 cases[46.7 %] and the next was lower a third thoracic esophagus[10 cases, 25.0%]. 4. In 33 of total 45 cases, colon interposition with right colon was performed without resection of the strictured esophagus except one case which was complicated esophageal cancer. Other procedures were 4 cases esophagogastrostomy with segmental resection, 2 cases of plastic repair and so on. 5. Major postoperative complications which were needed for secondary operation were 5 cases[11.1 %]. [2 cases of stenosis, ileus and ulcer bleeding respectively] Overall mortality rate was 4.4 %.

• Journal of Welding and Joining
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• 제11권3호
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• pp.48-60
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• 1993

The cause of corrosion failure found in structures or various components operating in severe corrosive environments has been attributed to stress corrosion cracking(SCC)which is resulting from the combined effects of corrosive environments and static tensile stress. Slow strain rate test (SSRT) provides a rapid reliable method to determine SCC susceptibility of metals and alloys for a broad range of application. The chief advantage of SSRT procedures is that it is much more aggressive in producing SCC than conventional constant strain or constant load tests, so that the testing time is considerably reduced. Therefore, in this paper, the combined effects of material properties and strain rate on the tensile ductility and fracture morphology of parents and weldment for SM45C, SCM440 and SM20C steels were examined and discussed in synthetic sea water. The susceptibility of SCC was the most severe under the strain rate of $1.0{\times}10^{-6} sec^{-1}$, and R.O.A. can be used for parent and maximum load for weldment to evaluate the parameter for SCC susceptibility.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.469-474
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• 2002

Recently fiber sheets are used for strengthening the damaged concrete structures due to its many advantages such as its durability, non-corrosive nature, low weight, ease of application, cost saving, control of crack propagation, strength to thickness ratio, high tensile strength, serviceability and aesthetic. However, the lack of analytical procedures for predicting the nominal moment capacity by the fiber sheet reinforcement leads to difficulties in the effective process of decisions of the factors in the strengthening procedure. In this work, flexural strengthening effects by fiber sheets bonded on soffit and web of the member are theoretically studied for the reinforced concrete T beam. The analytical solutions are compared with experimental results of several references to verify the proposed approach.

• 대한기관식도과학회지
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• 제5권1호
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• pp.30-35
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• 1999

Between 1994 to 1998, 7 patients had taken emergency operations by iatrogenic esophageal perforation. To evaluate patterns of injury, clinical presentation, and treatment options for patients, we reviewed all the 7 patients who had gotten transmural injury to the esophagus during dilatations or stenting procedures at our hospital. The primary diagnosis of the patients were as followings , two were achalagia and remaining five were corrosive esophageal strictures. Chest pain, fever, tachycardia were the early signs after esophageal perforation. The sites of perforation were thoracic esophagus in all cases and all of them underwent operation within 8 hours of initial injury. There were no postoperative mortality. Complications were developed three cases： stricture of anastomotic site, mediastinitis due to graft failure of colon and pleural empyema.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.983-988
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• 2000

Anchoring systems with structural stability and endurance have been one of the most important elements for PSC structures, especially for the structures using non-corrosive FRP tendons. FRP tendons are in increasing use for underground and coastal structures constantly contacted with fresh water or sea water because of their superiority to metallic ones in corrosion-resistance. In this study new non-metallic anchoring system for FRP tendons has been tested and investigated. The newly developed anchoring system utilizes FRP pipes and HEM (Highly Expansive Mortar). The major factors considered in this experiment were expansive pressure of HEM during its hydration and the strength of GFRP(Glass Fiber Reinforced Plastic) Pipe. Anchoring forces of the new anchoring system were investigated from the pull-out testes. The authors analyzed pull-out procedures of the FRP tendons in the various pipe filled with HEM and suggested an improved idea to develop novel non-metallic anchoring system for FRP tendons

• 한국산학기술학회논문지
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• 제9권1호
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• pp.170-175
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• 2008

본 연구에서는 상수도관의 부식방지를 위해 관망 내부에서 탄산칼슘의 침전 및 용해 여부를 판단할 수 있는 지표인 CCPP를 산정할 수 있는 프로그램을 개발하였다. CCPP 산정은 9단계 절차를 통하여 이루어지며, 평형상태의 pH를 가정하고 결정 식의 왼쪽 항의 합과 오른 쪽 항의 합이 오차의 범위에서 유사한 값을 주도록 반복계산을 수행하고, 다음 단계에서 초기 및 평형상태의 알칼리도를 대입하여 CCPP를 구한다. 프로그램 개발은 계산을 위해 포트란 언어를, 결과 값을 그래프로 표현하여 쉽게 판단할 수 있도록 비쥬얼베이직 언어를 사용하였다. 개발된 프로그램을 적용하여 한강 수계 Y정수사업소의 수질을 평가한 결과, 탄산칼슘의 불포화 상태가 심한 수질로 판명되어 부식성이 높은 것으로 평가되었다.

• Journal of Chest Surgery
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• 제22권1호
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• pp.134-140
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• 1989

A clinical evaluation was made on total 207 cases of corrosive esophageal stricture after ingestion of various corrosive substances and 173 cases of neoplasms in the esophagus and the cardia. The various complications associated with esophageal corrosion were observed on 28 cases [13.5%] in a total of 207 cases. Pathoanatomic findings of complication may be classified to the five category as follow; [1] stenosis in the pharynx due to adhesion of the epiglottis, [2] esophagobronchial fistula, [3] esophageal perforation with bougienation, [4] necrotic rupture of the esophagus and the stomach, and [5] so-called chronic corrosive gastritis. The comparative studies were done on a total of 165 cases of the various procedures of esophagoplasty to the reconstruction of the esophagus, which consists of antethoracal esophagoplasty with jejunum, retrosternal esophagoplasty with jejunum, retrosternal esophagoplasty with right colon, and retrosternal esophagoplasty with left colon. There is no hard and fast rule in selection of jejunum, right colon or left colon as the transplanting bowel and an operative method either antethoracal or retrosternal approach. When there was no possibility of the complication and no any defect of the anatomical states, one stage retrosternal esophagoplasty using right colon was better in various points of view. The 173 patients of the neoplasm of the esophagus consist of 28 cases of benign tumors and 145 cases of malignant tumors in the esophagus and cardia. 28 cases of benign tumors in the esophagus received the surgical treatment and they obtained with excellent results postoperatively. Of the 145 patients of esophageal carcinoma who received surgical managements, 101 cases [69.6%] were found to be operable and 44 cases [30.3%] were inoperable. Due to the various level of carcinoma in the esophagus, the following different surgical procedure was properly used case by case to get the best results in each case. Esophageal carcinoma in the upper and middle third segment received the total esophagectomy and the reconstruction of the esophagus using right colon by substernal procedure. Esophageal carcinoma in the lower third segment received an esophagojejunostomy in the mediastinum after the resection of lower third segment of the esophagus. Carcinoma in the esophago cardia and the stomach received also an esophagojejunostomy after the resection of the lower third segment of the esophagus and subtotal gastrectomy. For the 44 patients with inoperable carcinoma, the several palliative surgical managements such as gastrostomy or jejunostomy for feeding and esophagojejunostomy for bypass of the lower esophagus and the stomach were properly performed case by case for their maximum improvement.

• Archives of Plastic Surgery
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• 제36권1호
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• pp.113-117
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• 2009

Purpose: Although Hydrofluoric acid(HF) is not a strong acid when compared to other hydrogen halides, it is a feared corrosive and is particularly dangerous at higher concentrations. HF burns are characterized by symptoms, often delayed and localized with diluted HF solutions, to include erythema, edema and severe pain. Pain, a well known symptom following exposure to calcium binding. And, EMLA$^{(R)}$ cream is a topical formulation based upon the eutectic mixture of lidocaine and prilocaine and is used in clinical settings to provide pain relief undergoing superficial surgical procedures. The aim of this study is to evaluate effects of EMLA$^{(R)}$ cream, pain - control dressing on the treatment for HF injury wound. Methods: From June 2007 to June 2008, this study was carried out with 10 patients who had HF partial thickness burns. We were applied topically EMLA$^{(R)}$ cream to injured wound with vaseline gauze and 10% calcium gluconate wet gauze dressings. As a principle, in the emergency treatment, partial or complete removal of the bullae along with copious washing with normal saline was done, depending on the degree of HF invasion of the distal digital extremities. The effect of dressing was investigated by visual analogue pain scale. Results: We therefore reviewed 10 cases of HF - induced pain and pain relief treatment principle. The 10 cases who came to the hospital nearly immediately after the injury healed completely without sequelae and EMLA$^{(R)}$ related complications. Conclusion: Proper initial treatment of HF burns are important, if not promptly recognized and properly treated, for produce serious injury. Topical EMLA$^{(R)}$ cream remain a powerful, new advancement for minimizing HF - related pain during dressing procedures. When used appropriately, topical EMLA$^{(R)}$ cream can provide a safe and effective alternative to other forms of HF - pain control treatment.