• 한국생산제조학회지
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• 제21권2호
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• pp.191-195
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• 2012

Heavy flint optical glass(SF57HHT) is new material that has extremely high transmittance. Due to brittleness and high hardness, optical glass is one of the most difficult to materials for ultra-precision turning. According to the hypothesis of ductile machining, all materials, regardless of their hardness and brittleness, will undergo transition from brittle to ductile machining region below critical undefromed chip thickness. In this study, cutting test was carried out to evaluate cutting performance of heavy flint glass using ultra-precision machine with single crystal diamond bite. The machined workpiece surface topography, tool wear and surface roughness were examined using AFM and SEM. The experimental results indicate that the machining mode become the brittle mode to ductile mode, when the maximum undeformed chip thinkness is large than critical value. Tool wear mainly occurs on the flank face and its wear mechanism is dominated by abrasion. This study demonstrates the feasibility of SF57HHT by diamond turning.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.17-23
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• 2002

A cylindrical capacitance-type spindle displacement sensor was developed and its effectiveness as a system to monitor cutting forces during hard turning was tested in this research. The sensor was installed between the face of spindle cover and the chucking element and measured pure radial motion of the spindle under the condition with presence of roundness error at measured surface. To prove the effectiveness of the developed system hard aiming tests using ceramic inserts and tool steel as workpiece were conducted. The workpiece was hardened up to 65 Rc. The variations of pure radial motion of the spindle ware measured during the cutting tests. The signals from the sensor showed the same pattern of cutting force variations from the tool dynamometer due to the progress of tool wear. As the flank wear of the ceramic tool increased both static component of cutting forces and the amount of center shift of spindle orbit increased, Results from the research showed that the developed sensor could be utilized as an effective and cheap on-line sensing device to monitor cutting conditions and tool performance in the un-manned machining center.

• 대한기계학회논문집
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• 제17권1호
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• pp.27-37
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• 1993

본 연구에서는 공구의 파손 및 마멸량을 검출할 수 있는 시스템을 구축하고자 하였다. CCD(charge coupled device)카메라를 통해 공구형상의 영상을 얻고 이를 PC 로 분석하는 영상처리 기법과, 여기서 계산된 정보를 이용하여 패턴인식 기법으로 공 구의 상태를 판정하는 알고리즘을 개발하였다.

• The Korean Journal of Pain
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• 제1권1호
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• pp.91-97
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• 1988

Herein is a review of eigthy six surgical cases from March to August, 1986 which recieved tetracaine hydrochloride spinal anesthesia. In an attempt to relieve postoperative pain, 0.5 mg morphine sulfate was administrated into the lumbar subarachnoid space. Pruritus, a side effect of intraspinal morphine, was explored in detail. The results were as follows : 1) The incidence of pruritus was 67.4%, 65.5% in man and 71.0% in woman. 2) The time of onset of pruritus was between 30 and 120 minutes with an average of 79.1 minutes. 3) Pruritus primary occurred on the face(87.9%), especially on the nasal, perinasal and periocular areas. Other sites included the scalp, neck, chest, abdomen, shoulder, hip, thigh, flank, and whole body. 4) The severity of pruritus was classified as mild and moderate, but 4 cases(6.9%) were regarded as severe and were treated with naloxone. 5) The duration of pruritus was from 15 minutes to 19 hours with an average of 4.7 hours. 6) There was no significant difference in the prevention of pruritus between the group recieving diphenhydramine and the one which received normal saline.

• 기본간호학회지
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• 제17권3호
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• pp.314-323
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• 2010

Purpose: This study was performed to identify skin hydration status and skin surface pH according to the body parts of the aged with immobilization. Methods: The subjects were 101 aged patients in a hospital and a institution for the elderly in Seoul. Data for skin hydration and skin surface pH were collected using corneo-meter and skin pH-meter. The body parts of measurement were 10 parts; face, forearm, back of the hand, flank, upper abdomen, leg, back of the foot, heel, scapular, and sacrum. The data were analyzed by SPSS/WIN 12.0 program. Results: Skin hydration status were relatively low especially on lower extremity and back of body, and skin surface pH of scapular and sacrum were high. There was significant negative correlation between skin hydration status and skin surface pH on the 6 body parts. Conclusion: Skin hydration status and skin surface pH, especially on scapular, sacrum, and lower extremity need to be considered as important control factors for increasing skin health status of the aged with immobilization.

• 터널과지하공간
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• 제29권5호
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• pp.332-345
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• 2019

평사투영도에서 불연속면을 대표하는 유일한 점으로 정의되는 최대경사벡터를 해당 면의 경사와 경사방향에 의거하여 형성하였다. 평사투영해석에서 평면의 극점이 대원과 역방향에 제도되는 것에 비해 최대경사벡터는 대원의 최대 경사지점에 위치하여 불연속면의 미끄러짐 방향을 직접 투영도 상에서 지시한다. 투영도 상에서 불연속면의 거동방향을 직접적으로 지시하는 최대경사벡터를 활용하여 평면 및 전도파괴 양상을 직관적으로 확인하였다. 특히 평면 파괴의 경우 블록의 옆면을 형성하는 고 경사 절리의 존재를 확인하여 실제 미끄러짐 블록의 형성가능성을 산정하였다. 또한 사면 방향과 반대방향을 갖는 고경사절리들의 존재를 확인하여 3각형 단면을 갖는 미끄러짐 블록의 형성여부를 판별하고 안전율을 도출하였으며, 4각형 단면을 갖는 가장 취약한 블록의 안전율과 비교분석하였다. 쐐기파괴 경우에는 절리면 교차에 의해 형성되는 쐐기의 기저선 방향이 최대경사벡터 속성을 지니고 있어 쐐기파괴 영역을 평면 및 전도파괴 영역이 제도된 투영도 상에 함께 도시하여 분석을 수행하였다. 특히 쐐기 상부 면을 형성하는 절리를 추출할 수 있어 전체 쐐기형상을 추정하고 역학적 거동분석을 수행하는데 요구되는 쐐기의 기하학적 특성자료를 도출하는 토대를 확립하였다.