플륨 모니터링에 의한 SM45C 레이저 용접특성 평가

유영태,김재열,노경보,양동조,오용석,임기건,김지환 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.6

With the increased use of lasers in industrial welding applications, techniques for monitoring and controlling these processes become increasingly important. It is very important that we understand the dynamic behaviors of the laser induced plume in welding because the laser induced plume has considerable effects on welding efficiency and the quality of materials. As the plume fluctuation was associated with keyhole instability, unstable vapor plume indicated the process was unstable and would result in poor welds. An Infrared Themal-vision Camera can be utilized compensate for incurracies encountered in real-time monitoring during laser welding. We have results that instabilities of plume are closely dated with hot cracking and defect of laser welding.

훈증소독에 따른 서화류의 안료변색 및 pH변화 유무 조사

유혜영,김경수,이용희 국립중앙박물관 1999 박물관보존과학 Vol.1 No.-

문화재의 생물피해 예방에 주로 활용되는 壎蒸消毒[메틸브로마이드와 에틸렌옥사이드 혼합 가스]이 書畵類에 어떤 영향을 미치는지에 대하여 간략한 調査를 실시하였다. 彩色이 있는 조선시대 古地圖와 繪畵 등 13점을 대상으로 훈증소독 前과 後의 顔料의 變色 또는 退色의 有無 그리고 종이의 pH변화 등에 대하여 測定하였다. 그 結果 旣存의 문화재 훈증소독 適用基準[가스의 湯度, 暴露시간 등]을 지킨 조건에서는 안료의 변·퇴색 현상을 발견하지 못했으며 종이의 酸性化에도 영향을 미치지 않는 것으로 확인되었다. This is a brief study on the influence of fumigation (using mixed gas of methyl bromide and ethylene oxide) on old paintings. Fumigation is principally used to prevent biological damage of objects. Thirteen objects, including old colored map from Choson Dynasty and some paintings, were selected for this research. Before and after fumigation, color measurements were made and changes of pH value were measured. The result is that the fumigation did not affect on discoloration of colored area and acidity of paper, as far as the standard of application (such as concentration of gas, exposing time and ect.) of fumigation was kept.

연속파형 Nd:YAG SM45C 레이저 용접의 결함 감소연구

유영태,오용석,노경보,신호준 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.1

본 연구에서는 Nd:YAG 연속파형 레이저를 이용하여 레이저 용접시 레이저빔의 출력에 대한 레이저범의 이송속도를 변화시켜 심입용접을 실시했다. 열처리를 하지 않고 용접을 실시했을 경우 매우 조대한 기공이 많이 발생하였지만 열처리 후 용접을 실시했을 때는 몇몇 미세한 기공만 발생하였다. Present investigation reports on the effect of incorporating pre-heating on the mechanical properties of laser weldi'ng joints. The Nd:YAG laser in combination with the optical fiber increase the automation and the flexibility of a whole industry. The Nd:YAG laser welding process is one of the most advenced menufacturing technologies owing to its high sped and penetration. This paper describes the weldability of Sh4456 carbon steel fox machine structural use by Nd:YAG laser. Optical microscopy SEM were performed to observe the micro structures and to determine the structures of welded zone. In addtion, mechanical propreties, were measured by tensile test to evaluate the formablity of the welded specimen. The results show that proper selection of the control parameters for per-heating technique can result the porosity and cracking of the welding significantly, and improve the welded joints mechanical properties, such as higher tensile strength and better durability.

오스테나이트계 304 스테인레스강과 Nd-YAG 레이저빔과의 상호작용

유영태,오용석,노경보,임인호 조선대학교 에너지.자원신기술연구소 2002 에너지·자원신기술연구소 논문지 Vol.24 No.1

Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and penetration. The thermal cycles associated with laser welding are generally much faster than those involved in conventional arc welding processes, leading to a rather small weld zone. The experiments are performed for 304 stainless steel plate applying variation of : laser power(600~2000W), welding speed (3~10m/min), shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar and plates, etc. The variation of brightness temperature versus modification of operational parameters is found, certain typical welding defects can be detected.

혈액 질환 진단용 화상 정보 시스템의 개발

이영준,박상권,이유경,박성섭,조한익 대한임상병리학회 1996 대한임상병리학회지 Vol.16 No.5

혼수상태의 외상환자에서 초음파를 이용한 흉부 및 복부손상의 진단

임경수,이강현,이진웅,이부수,황성오,유수영,강성준 대한응급의학회 1995 대한응급의학회지 Vol.6 No.1

The need for rapid diagnosis and treatment of life-threatening thoracic and intra-abdominal injury result in controversy over the appropriate triage of unconscious blunt trauma patients. To aid in early decisions for these patients, a prospective analysis of 98 patients with glasgow coma scale(GCS) scores≤8 was undertaken. Although intra-thoracic and intra-abdominal injuries were frequently identified based on systolic blood ressure, the use of clinical signs alone resulted in more missed injuries than did using the emergency ultrasonography. In normotensive patients(n=34), intra-thoracic injuries was identified in one patient(2.9%), and intra-abdominal injuries were in 7 patients(20.6%). In shock(systolic blood pressure<90mmHg) Pa-tients(n=64), thoracic injuries and intra-abdominal injuries were diagnosed in 8(12.5%) and 27 patients(42.3%), thoracic and abdominal combined injuries were identified in 11 patients(17.2%). The sensitivity, specificity, and accuracy of emergency ultrasonography were 96.3%, 91.7%, 94.9%. This study suggests that all unconscious trauma patients undergo immediate emergency ultrasonography to prevent missing life-threatening injuries.

Flubendazole의 편충에 대한 구충효과

최원영,남호우,유채을,한인수,한경용 최신의학사 1988 最新醫學 Vol.31 No.7

적외선 열화상 카메라를 이용한 Plume 형상에 따른 Nd:YAG 레이저 용접 결함 평가

김재열,유영태,양동조,송경석,노경보 한국비파괴검사학회 2003 학술대회 논문집 Vol.- No.1

In Nd:YAG laser welding, evaluation methods of welding flaw are various. But, the method due to plume shape is difficult to classification of welding flaw. The Nd:YAG laser process it known to have high speed and deep penetration capability to become one of the most advanced welding technologies. At the present time, some methods are studied for measurement of plume shape by using high-speed camera and photo diode. This paper describes the machining characteristics of SM45C carbon steel welding by use of an Nd:YAG laser. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. In this study, plume shape was measured by infrared thermal camera that is non-contact /non-destructive thermal measurement equipment through change of laser generating power, speed, focus. Weld was performed on bead-on method. Measurement results are compared as two equipments. Here, two results are composed of measurement results of plume quantities due to plume shape by infrared thermal camera and inspection results of weld bead include weld flaws by ultrasonic inspector.

시스템 다이내믹스를 이용한 간호단위별 간호인력 산정에 관한 연구

김문실,성영희,권경자,김도형,김정아,신덕신,유인자,유재국,이현숙 병원간호사회 2006 임상간호연구 Vol.11 No.2

Purpose: The purpose of the study was to forecast manpower by building the nursing manpower-staffing model(surgical-medical nursing unite). Method: The system dynamics approach was adapted to build a simulation model for calculating medical-surgical nursing manpower-staffing. The model was built up on Venism 5.0b DSS. Result: The results in the basic circumstance are in following. The level of nursing service quality, patientsatisfaction, and nurse job satisfaction maintains higher at medical-surgical nursing unit of the tertiary hospitals with the ratio of bed to nurse 2.5:1-3.0:1 than at any other situations. The level of nursing service quality, patient satisfaction, and nurse job satisfaction maintains higher at madical nursing unit of the secontary hospotals with the ratio of bed to nurse 3.0:1 and at surgical nursing unit of the secondary hospitals with the ratio of bed to nurse 3.0:1-3.5:1 than at any other situations in the fundamental from. The results in the simulation circumstance are in following, As author raises the operating rate of bed into 95-100%, and cut skilled nursing staff down, the level of nursing-service quality, patient satisfaction, and nurse job satisfaction drops slightly. Conclusion: In terms of economic efficiency on tertiary hospotals, the ratio of bed to nurse for the best reasonable medical-surgical nursing manpower-staffing is 3.0:1. In terms of economic efficiency on secondary hospitals, the ratio of bed to nurse for the best reasonable medical nursing manpower-staffing is 3.0:1 and surgical nursing manpower-staffing is 3.5:1

다발성 외상시 응급 초음파검사의 의의

이강현,임경수,김선만,김영식,황성오,유수영,강성준 대한응급의학회 1995 대한응급의학회지 Vol.6 No.1

The Evaluation of blunt abdominal trauma is clinically challenging. Abdominal computed to-mography(CT) and diagnostic peritoneal lavage(DPL) has become primary diagnostic modali-ty in advanced trauma life support(ATLS). But DPL is invasive study with potential for the patients. Monitoring and resuscitation are usually suboptimal during there examinations. We examined the efficacy and role of emergency ultrasonographic(US) studies in the initial abdominal evaluation of blunt trauma patients. A prospective study was carried out on 101 blunt trauma patients from 1994, June to September. 101 patients underwent real-time US ex-amination of the chest and abdomen. Indication for emergency US included the cases of shock (systolic blood pressure<90mmHg) or tachycardia (pulse rate/min.>100) in blunt trauma pa-tients. US showed a sensitivity of 96.2%, specificity 98%, accuracy 97% in regard to indica-tion for surgery in case of blunt abdominal or thoracic trauma. US saves time, and it can be performed during the emergency care in the emergency department. US showes high sensitivity and specificty, and is the method of first choice in the evaluation of blunt trauma.