• 한국화재소방학회논문지
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• 제25권6호
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• pp.32-38
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• 2011

산업현장에서 폭발성가스의 사용이 꾸준이 증가 함에 따라 작업자는 물론 일반지역주민들에까지 사고로 인한 생명에 위험을 처하기도 한다. 수소사용공정에서의 사고피해는 공정자체에 국한 되는 것이 아니라 대형화재나 폭발로 이어져 다수의 사상자를 유발시키므로 사고의 유형과 원인을 규명하고 피해규모를 예측하여 이에 대한 안전대책을 수립, 운영하는 것이 필요하다. 본 연구에서는 MLCC(Multi Layer Ceramic Capacitor) 소성공정의 수소저장 사용시설에서 화재 폭발시 위험범위를 예측하였다. 실제 사고데이터의 분석결과 사고발생빈도가 가장 많은 배관누출에 대하여 사고 피해예측 시나리오 모델로 선정, 적용하였다. 10 mm Hole에서 120 Bar의 압력으로 수소가스 누출시 Jet fire가 발생되며 Radiation Level 4($kw/m^2$)의 경우 최대 12.45 m까지 복사열의 영향을 주었다. 또한 사고피해 예측을 통한 안전성확보와 개선방안을 제시하였다.

• Journal of Information Display
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• 제3권4호
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• pp.19-22
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• 2002

In this paper, we introduce an efficient three-dimensional magnetic field mapping system for a Deflection Yoke (DY) in Cathode-Ray Tube (CRT). A three-axis Hall probe mounted in a small cylindrical bar and three-stepping motors placed in a non-magnetic frame were utilized for the mapping. Prior to the mapping starts, the inner contour of DY was measured by a laser sensor to make a look-up table for inner shape of DY. Three-axis magnetic fields are then digitized by a three-dimensional Hall probe. The results of the mapping can be transformed into various output formats such as multi pole harmonics of magnetic fields. Field shape in one, two and three- dimensional spaces can also be displayed. In this paper, we present the features of this mapping device and some analysis results.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.41-41
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• 2009

To evaluate the applicability of dissimilar joining between Mg and Al alloys in automobile manufacturing process, solid state joining processes such as magnetic pulse welding(MPW), friction stir welding(FSW) and friction spot joining(FSJ) were attempted successfully. MPW process has been concentrated mainly on round section tube to tube and tube to bar welds. AZ31 Mg alloy has been successfully welded to pure Al A1070 as well as to Al alloy A3003. While, for friction stir welding of dissimilar sheet joints, AZ31B/A6061 with the thickness of 2mm were used and a square butt joint with a good quality was obtained at the conditions of 0.8mm/sec of travel speed and tool rotation speed of 850rpm. The maximum tensile strength of 179 MPa, which was about 80 % of the Mg base metal tensile strength, has been obtained. Finally, friction spot joining was attempted to make a dissimilar lap joint between AZ31(0.8mm) and A6061(1mm), while the joint exhibited the same level of tensile shear strength as that of similar Mg joint.

• 한국융합학회논문지
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• 제8권12호
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• pp.275-281
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• 2017

카울크로스바는 차체의 계기판 후면에 설치되는 보강 부품으로서 최근 부품의 기능 개선 및 차량 경량화의 요구로 인하여 점차 복잡한 형상의 제품이 개발되고 있다. 특히, 제품 좌우의 지름과 두께가 서로 다른 경우에 이직경 파이프의 용접을 통하여 제품이 생산되는데, 외관 품질 및 기계적 성질의 저하 문제가 지속적으로 제기되어 소성 가공을 이용한 일체화 성형 기법의 개발이 요구되고 있다. 본 연구에서는 좌우 형상이 서로 다른 직선형 카울크로스바에 대한 일체화 성형 기법으로서 복합 인발 공정과 스웨이징 공정을 개발하였으며 기계적 성질 및 생산비의 관점에서 개발 공정들을 비교하고자 한다. 결론적으로 일체화 성형 제품이 기존 용접 제품에 비해 우수한 굽힘 강도를 보이며 스웨이징 공정을 사용할 경우 보다 저렴한 비용으로 생산이 가능함을 알 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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• pp.88-101
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• 1992

Properties of water and steam are very important for the steam ejector CAD program as a subroutine and design of the Shell & Tube type steam condenser. Present formular programs are based on the Skeleton Table of ASME, and are able to calculate the thermodynamoc properties of water and steam throughout the whole of the region that extend in pressure from 0 to 1000 bar and temperature from 0.01 to 80$0^{\circ}C$. When comparing calculated values for specific volume, enthalpy and entropy with the Skeleton Table 1967 and IAPS Skeleton Table 1984, values fell well within tolerances specified except near the extremes of the range of interest at the critical point and triple point, where deviations were slightly larger.

• 한국기계가공학회지
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• 제11권5호
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• pp.88-93
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• 2012

This paper describes the machinability of the sintered carbide and tool-die steel(STD-11) by electric discharge drilling with various tubular electrodes which have multi-holes. Various types of electrode which have different diameters and materials are used with the application of continuous direct current and axial electrode feed. Inner part of electrodes are inserted with smaller tubes or Y-channel or bar. In ED-Drilling, the dielectric flushed down the interior of the rotating tube electrode, in order to remove machining debris from the hole. As result of experiments, the bigger the diameter of the electrode is, the lower the material removal rate is. Machinability of copper electrode is higher than that of brass. In machining of sintered carbide, to use oil is better than distilled water as dielectric.

• Advances in pediatric surgery
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• 제13권2호
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• pp.112-118
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• 2007

Ingested foreign bodies are common occurrences in the pediatric population. From October 2002 to April 2006, eight patients (6 male, mean age: $30.9{\pm}14.4$ months, range: 7~45 months) who had ingested metallic foreign bodies, such as bar magnets, coin-type magnets, screws, metal beads, and disk batteries, were selected for foreign body removal using a magnetic device under floroscopic control. A 1-cm-long cylindrical magnet (6 mm in diameter) was placed at the end of a 150-cm-long plastic tube from an IV set. The magnet was passed through the mouth into the stomach. Under fluoroscopic control, the magnet was maneuvered so that it attached to the metallic foreign bodies. The forgeign body was then easily removed by retracting the magnet with the metallic object attached. This procedure was successful in six patients of 8 patients. This procedure is a minimally-invasive and may avoid the use of anesthesics, endoscopy or surgery.

• 대한토목학회논문집
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• 제29권6D호
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• pp.753-760
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• 2009

본 연구는 2001년부터 2008년까지 건설자재 가격의 변동에 따른 부산시 공동주택의 분양가 변동을 분석하고자 하였다. 주요 분석결과는 다음과 같다. 첫째, 본 연구는 공동주택의 대표 건설자재로 건축비에서 가장 큰 비중을 차지하는 철근과 레미콘, PHC파일, 동관 총 4가지 자재를 대상으로 분석을 실시하였는데, 철근과 동관의 경우 각각 연평균 14.03%, 14.91%로 높은 가격 상승을 보인 반면, 레미콘은 연평균 0.86%, PHC파일은 2.41%의 상승으로 거의 가격 변동이 없는 것으로 나타나 자재별 가격 변동의 격차가 크다는 사실을 알 수 있었다. 둘째, 공동주택의 분양가와 건설자재 가격의 변동에 관한 연관성을 분석한 결과에 의하면 철근과 레미콘, PHC 파일, 동관 모두 공통적으로 3개월 시차에 의한 영향이 가장 높게 나타났으며, 6개월 시차, 9개월 시차를 둘수록 그 영향력은 조금씩 감소했다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.223-228
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• 2001

The thermoacoustic refrigerator has not only considerable possibility but also commercial usability, because it has high reliability, lower vibration, no moving part, and can easily be constructed. In this study, The thermoacoustic refrigerator were constructed. The apparatus is capable of driving closed systems containing He or air at mean pressures ranging from 1-9.3 bar, at frequencies ranging from 100-1000Hz. The resonance characteristics of the thermoacoustic refrigerator were investigated for better performance, The resonance tube is 340.5mm in length. In case of using air as a coolant. Freezing frequency is 174Hz, In case of using He as a coolant Freezing frequency is 625Hz. Using He, The cold-part temperature of the heat exchanger fell to $-23.7^{\circ}C$ after 120 minutes in 70W.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.273-280
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• 1997

Rotary swaging is a process for reducing the cross-sectional area or changing the shape of bar, tube or wires by repeated radial blows with one or more parirs of opposed dies. The present study is concerned with investigation the effect of process parameters upon product quality(hardness, roughness, precision of dimension). To enhance the product quality, experimental works are carried out for some process parameters such as forming speed, billet shape, lubrication, reduction of area and ratio of t/D. Rod shift formed by RSM25 under cold conditions has good surface quality, hardness and precision of dimension. The recommendable process conditions are suggested for solid and tubular products.