세라믹 재료의 마찰 및 마멸 특성 해석에 관한 연구

李英悌 홍익대학교 산업기술연구소 1994 産業技術 Vol.4 No.-

Within the practical ranges of speed and load. The formation of transfer film and the consequent effects on the friction and wear behavior of ceramic materials during repeat pass sliding contact was studied. This was done using a steel and three ceramics viz silicon nitride alumina and silicon carbide with a cylinder on flat test configuration. The transfer film whenever formed is strongly attached enough to resist being siped off by the slider. As a consequence the formation of this film leads to a decrease in the wear rate because of the protection role of the film The presence of the film at the contack interface also results in high friction.

선접촉을 하는 베어링 접촉면에 형성되는 윤활유막 특성 해석

李英悌 홍익대학교 산업기술연구소 1993 産業技術 Vol.2 No.-

In load sharing model, the load is supported by the contacting asperities and the lubricants. The asperity contact area of two sliding surfaces are relatively very small as compared with the apparent contact area. The asperity contact pressure is relatively higher than the lubricant pressure. With the combined effect of asperity and lubricant pressure, the surface roughness and temperature rise must be considered to calculate the lubricant film thickness.

윤활유 개발을 위한 고온에서의 강철의 윤활특성 해석

李英悌 홍익대학교 산업기술연구소 1992 産業技術 Vol.1 No.-

Effective "break-in" and "scuff" damage of boundary lubricated steel surfaces was found to be due primarily to the rate of growth of "protective" films of oxides and compounds derived from the lubricant. The protection afforded by the films is strongly dependent on lubricant chemistry, steel composition, initial surface roughness and the load/speed sequence or history in the early stages of sliding. The protective films, formed by chemical and mechanical action between lubricant and mating surfaces, delayed the surface roughening and offered higher load capacity. Especially, the temperature rises due to sliding speed and load change lubrication characteristics. With consideration of temperature rises the characteristics of the protective films should be analysed to verify the lubricating and wear phenomena. Even the great number of variables involved it is not possible to follow more than a few of the chemical changes on surfaces using the electron/ion/x-ray column analytical instruments at the end of experiments. Ellipsometry was therefore used to monitor the formation and loss of dual protective films in real time, and also to find the effect of protective films on scuffing and break-in depending on lubricant conditions.

세라믹의 윤활조건 변화에 따른 마멸특성

이영제 成均館大學校 科學技術硏究所 1996 論文集 Vol.47 No.1

The friction and wear behaviors of ceramics against steels with lubricants were investigated and compared with those in air. The investigated ceramics were Al_2 O_3, SIC, and Si_3N_4. A cylinder-on-plate tribometer with rotated sliding motion was used for the experiments. SIC showed excellent wear resistant behaviors in water sliding, which was the lowest among tested ceramics, but very poor in oils. In case of Si_3N_4, the wear rates were low under oil environment, but the highest in water. The wear rates of A1_20_3 were very low in both lubricating conditions at low values of the frictional power, but high at high values of the frictional power.

摩擦力과 摩滅率을 利用한 潤滑油의 性能 比較

李英悌 홍익대학교 산업기술연구소 1994 産業技術 Vol.3 No.-

The Characteristics of lubricating oils are very important to prolong the life of automotive engines. The proper selection of oils will increase the power of engines and decrease the air pollution. Most reports on this area focused on the chemical and metallurgical aspects. On mechanical aspect the frictional force and the wear rates are critical parameters by which consumer can selects the oils. In this paper, three oils (two domestic, one imported) are used to make some plot for frictional forces and wear rates. From the plots, it is very simple to compare the characteristics of lubricating oils.

윤활환경 변화에 따른 SiC와 강의 마찰과 마멸 특성

이영제 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.2

The friction and wear behaviors of SiC against steels with lubricants were investigated and compared with those observed in air. Lubrications were done by water and commercial engine oil as received. Steels with 0.2 wt.% C were heat treated to obtain tempered structure. A cylinderon-plate tribometer with rotated sliding motion was used to carry out the experiments. In the experiments reported here, the range of different testing speeds and loads was used. It was found that the friction and wear characteristics of tested pairs were significantly influenced by environments. Two environments reduced wear of SiC by two digits compared with dry sliding at the same values of the frictional power, which are the products of the friction coefficient, the load and the sliding speed. Th frictional power showed very good relations with the wear rates of SiC.

대장직장종양에 있어서 Hand-Assisted Laparoscopic Surgery (HALS)의 초기 경험

조호영,최선근,구지회,허윤석,이건영,김세중,조영업,안승익,홍기천,신석환,김경래,우제홍 대한내시경복강경외과학회 2003 대한내시경복강경외과학회지 Vol.6 No.-

토양산성화에 따른 양이온 교환능력 특성에 관한 연구

金惠影,李在鎔,任齊彬 全北大學校 附設 都市및環境硏究所 1996 都市 및 環境硏究 Vol.11 No.1

The purpose of this study is to survey the pH variation of the soils, cation exchange capacity and organic matter by acid rain or acid matter, which is a cause of solid acidification. Three different soils were collected from paddy fields soil, fields soil and forest soil in Chon ju city. Artificial acid rain samples were made in distilled water with sulfuric acid. The pH are controlled pH 3.3 In this study, cations : H^+, Ca^2+, Mg^2+, Na^+, Al^3+ were analyzed. These ions are believed to be the major ions playing an important role in affecting acidity in rain. The cation exchange capacity(CEC) and organc matter were analyzed by Methods of Soil Analysis Part 2. The major ions were measured by ion chromatography and inductively coupled plasma(ICP) From the results, the following coclusions were derived. 1) In this batch test, it is identified that soil from paddy fields showed the pH variation of testing and the pH was 8.01 2) Exchangable cations, : Ca^2+, Mg^2+, Na^+ were measured in paddy fields soil, too. Their quantities were five times more than in other soils. 3) Aluminum ion having toxicity to plant-vegetation was eluted under pH 3. As it was eluted the very smallest quantity in the paddy fields soil, the paddy fields soil is hardly influenced by aluminum ion. 4) Most of all organic matters were measured at Paddy fields soil most of all. this has the smaller adsorption any other soils.

自動測定에 따른 大氣汚染分析

任齊彬,李秀令 全北大學校 附設 都市및環境硏究所 1990 都市 및 環境硏究 Vol.5 No.-

The analytical results of SO_2, CO and NO_2, O_3 by semi-auto analyzer, which have been setted for grasping the current-situation of air pollution caused by Chon-ju Industrial Complex could be summarized as follows. The average SO_2, CO, NO_2, and O_3 concentration in Chon-ju is 0.019 ppm, 1.67 ppm, 0.0175 ppm, 0.010 ppm, respectively. SO_2 usually surpasses "environmental standards" two or three thimes a month. In case of NOX is influenced almost by traffic conditions, NO_2 increase during daylight if NOX is influenced almost by traffic conditions, NO_2 increase during daylight if NOx would be high. Therefore, the sun-light causes NO_2 to degrade into increasing O_3. The Auto-Analyzer installed in Cheonju Area appears to cause some problems about its meauring site around chonju industrial Complex in the wind direction. SO_2, NOx and CO, O_3 turn out to be higher because the measuring site is being at the north-west down wind direction of Cheon-Gun Road and Samye Cross-Road.

축 진직도 측정 및 교정 자동화에 관한 연구

玄淸男,韓仁煥,李英悌 홍익대학교 산업기술연구소 1994 産業技術 Vol.3 No.-

This paper presents an efficient method in automatic measuring of shaft straightness and correcting shafts. During the rotation of a shaft, contact measuring pins touch the shaft to measure runout, and the angle of runout is detected by an encoder. For the correction of runout, a simple rule is developed. The control of correction is achived by the pressing stroke, not by the pressing force. The developed system is to correct runout within the allowable tolerance.