• Tribology and Lubricants
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• v.7 no.2
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• pp.13-21
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• 1991

선박은 사람이나 화물을 수상(水上) 운송수단의 목적으로 오랜 옛날부터 사용하여 왔으며, 금세기에 이르러서는 오랜 옛날부터 사용하여 왔으며, 금세기에 이르러서는 인류문화의 급속한 발전에 따라 주변생활이 가속화(Speed화), 합리화되어 문명의 혜택을 보다 많이 누리게 된 반면에, 국제간에 파생되는 여러가지 교환현상을 바탕으로 지구는 하나의 촌(村)으로 되어 유통경제를 지배하고 이용하는 운송수단으로 발전되어 왔다. 물질문명이 급속히 발전하는 작금, 선용추진 주 기관의 동향을 살펴보면, 1981년 세계에서 건조한 2000톤급 이상의 선박은 940여척으로 이중 13척이 증기 Turbine. 추진(推進), 나머지는 미끄럼 저속 디이젤 또는 중고속 디이젤 추진으로 되어있다. 이와 병행하여 선박에 쓰여지고 있는 각종 윤활제는 주기관으로서 디이젤 engine, Trubine engine, 가솔린 engine, 석유, engine, 선외기, 왕복동 증기기관, Journal계열로서 역전기, 추력베어링, 중간 베어링, 프로펠러베어링, 일반상선으 보조기계로서 발전기, 공기압축기, Boiler, 각종 Pump, 각종 Motor, 냉동기, 조타장치, Side Thrust, 갑판기계, 환기용 송풍기 및 통풍통, Oil 청정기, 수밀로(水蜜爐), 소화설비, 주기 개방용 천정 크레인, elevator, 어선으로서의 주 기관, 보조기기 등에 쓰여지고 있으며 이밖에 수중날개선 등에도 적용되는 등 실로 다양다종한 윤활제가 요구되고 있음에, 본 논고에서는 제목 건을 중심으로 한 선박과 윤활의 중요 Point만을 간추려 기술하고져 한다.

• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.77-82
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• 2010

This study has conducted numerical analysis for lubrication system of transmission for commercial vehicle. The lubrication oil system in transmission can be applied to a large scale commercial vehicle which is over 15tons. The flow rate of lubricating oil has been obtained for each of branch port from the lubrication pipe. The results from numerical simulation are mainly suggested for the mass flow rate of lubrication oil in the rotating main shaft of transmission system. It has been found that the mass flow rate from oil hole increased with an rotating rate of main shaft. The flow characteristic from oil hole has been presented for the lubricating system in the manual transmission.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.160.2-160.2
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• 2005

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.11a
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• pp.15-22
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• 2002

To carry out perfectly the forming analysis of the extruding products, it is necessary that the friction boundary condition between dies and blanks should be worked out the accuate numerical friction models. But the numerical friction models adapting in the conventional Extrusion forming software may be large different from the actual conditions. Expecially, the use of the existing extrusion forming software is possible only in the limitted range owing to the unaccuracy of the high speed forming work. Therefore, tile prepare of this study is to develop the numerical friction model which describes the friction boundary condition mathematically well, to improve the accuracy of the extrusion farming analysis, and finally to expand the applying areas of the results.

• Journal of Drive and Control
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• v.11 no.1
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• pp.14-24
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• 2014

Variable displacement vane-type oil pumps represent one of the most innovative pump types for industrial applications, especially for engine lubrication systems. This paper presents a complete and accurate mathematical model for a typical variable displacement vane-type oil pump. Firstly, its theoretical model is revised. Secondly, an analysis of power loss factors of this pump type is carefully investigated to optimize the modeling accuracy. Finally, the estimated pump performance using the complete pump model is verified by numerical simulations in comparison with the practical tests.

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1071-1077
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• 2000

표면 윤활층을 가진 나노 알루미나를 진공중에서 가압성형함으로써 결함발생없이 높은 충전압력을 가할 수 있었으며, 높은 밀도, 미세기공, 좁은 기공경 분포를 가지는 성형체를 제조할 수 있었다. 윤활제의 화학 및 기계적 특성에 의하여 변하는 모세관 현상을 조정함으로써 충전효율을 증대하고 결함발생을 억제할 수 있다. 나노분말의 소결에서도 성형 미세구조의 균일도가 치밀화 거동에 여전히 지배적인 역할을 하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.04a
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• pp.242-246
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• 1997

Diamond grit was coated with Ti by RF Sputtering to investigate the effect of coated diamond particles on performance of diamond impregnated saw. Coated and uncoated powders were separately mixed with 70Co-30W(wt %) powders by conventional milling technique. Hot pressing was carried out to make specimens. The wear test were carried out with these two types of diamond impregnated specimens. It was demonstrated that Ti coating was effective in improving the ability of grit retention and thus enhanced the tribological performance of diamond tool.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.7-8
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• 2006

본 논문은 Synthetic Bearing(Thordon bearing)을 적용하여 발생한 문제점을 분석, 대책 수립

• Tribology and Lubricants
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• v.37 no.6
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• pp.253-260
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• 2021

Metal pipes are used in a wide range of applications, from plumbing systems of large construction sites to small devices such as medical tools. When a liquid is enforced to flow through a metal pipe, a higher flow rate is beneficial for higher efficiency. Using high pressures can enhance the flow rate yet can be harmful for medical applications. Thus, we consider an optimal geometrical design to increase the flow rate in medical devices. In this study, we focus on cannulas, which are widely used small metal pipes for surgical procedures, such as liposuction. We characterize the internal flow rate driven by a negative pressure and explore its dependence on the key design parameters. We quantitatively analyze the suction characteristics for each design variable by conducting computational fluid dynamics simulations. In addition, we build a suction performance measurement system which enables the translational motion of cannulas with pre-programmed velocity for experimental validation. The inner diameter, section geometry, and hole configuration are the design factors to be evaluated. The effect of the inner diameter dominates over that of section geometry and hole configuration. In addition, the circular tube shape provides the maximum flow rate among the elliptical geometries. Once the flow rate exceeds a critical value, the rate becomes independent of the number and width of the suction holes. Finally, we introduce a slippery liquid-infused nanoporous surface (SLIPS) coating using nanoparticles and hydrophobic lubricants that effectively improves the flow rate and antifouling property of cannulas without altering the geometrical design parameter.

• Journal of KSNVE
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• v.6 no.1
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• pp.107-114
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• 1996

The damping characteristics of a cylindrical structure containing oil and bearing balls is investigated for external bending forces. The experimental data obtained through the use of bearing balls with viscous oil in a column is given and analyzed. The viscous action of the oil and inertia effects of the balls on the inside of column create a drag force. The drag force dampens the vibration of the column. This study aims to search for an optimum combination of oil and balls which would produce maximum damping. Machining oils of various viscosities along with ball bearings of various sizes place inside cantilevered aluminium tubes of various diameters to create a rig on which the damping properties of the oil and balls can be studied. The contileved tubes are studied in both horizontal and vertical positions in order to gauge the effect of gravity on the system. The actions of the ball in the column and damping characteristics are investigated according to the dimensionless terms. The Buckingham theorem is used to reduce the variables and to predict the damping of an oil ball column. Though the damping ratio remains fairly constant in the horizontal position of column, the damping ratio begins to increase as the ratio of the number of balls and column length rise above 0.28 in the vertical position of oil ball column. The ratio of the ball diameter to column diameter influences the damping ratio with an optimum diameter ratio. Slenderness ratio and gravity effects on the damping ratio ane investigated.