• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1006-1007
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• 2006

The oil-impregnated sintered bearings are used for various aplecations and, wide usages without refueling. The oil circulating mechanism operates smoothly the behavior of oil If doing at the time of passing and becoming a stationary state, and there is little thing where trouble is caused. On the other hand, the trouble of such as starting noise might be caused in the unstationary state that repeats operation for a short time. To study the behavior of oil of each parameter, we execute the numerical simulation and various verification experiments. As a result, we developed that the bearings were able to be used enough for various brief operating time in the unstationary state. Finally we have expanded the usage of the oil-impregnated sintered bearings by adding the consideration of the behavior of oil.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1682-1691
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• 2018

Natural ester is a suitable substitute for mineral oil and has been widely used in AC transformer in many countries. In order to further application of natural ester in direct current (DC) equipment, it is needed to investigate its long term insulation property under DC condition. In this paper, a thermal ageing experiment was conducted for both mineral oil-paper and natural ester-paper insulation. The DC breakdown and space charge characteristics of insulation paper impregnated with natural ester and mineral oil was compared. Results show that the resistivity of the paper immersed in natural ester and mineral oil both increase as the ageing goes on. While insulation paper impregnated with natural ester has higher resistivity and DC breakdown voltage than the paper impregnated with mineral oil. The DC breakdown voltage for the oil impregnated insulation paper being DC pre-stressing is higher than that without pre-stressing. The average DC breakdown field strength difference between the test with pre-stressing and without pre-stressing clearly shows that there is an apparent enhancement effect for the homo-charge injection on the DC breakdown.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3059-3064
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• 2013

In this study transesterification of Triglycerides (TG) from Jatropha curcas oil (JCO) with methanol for production of biodiesel was investigated over cerium impregnated ZSM-5 catalysts. NaZSM-5 was synthesized in an alkaline medium and impregnated with cerium oxide by wet method using cerium nitrate as a source for cerium. They were characterized by X-ray diffraction (XRD), Thermogravimeteric analysis (TGA), $CO_2$-temperature programmed desorption, and $N_2$ adsorption/desorption analysis. XRD analysis showed decrease in intensity of the patterns with the increase in the ceria loading but crystallization of ceria to larger size is an evident for 10 and 15% loading. The optimal yield of transesterification process was found to be 90% under the following conditions: oil to methanol molar ratio: 1:12; temperature: $60^{\circ}C$; time: 1 h; catalyst: 5 wt %. Here the yield of fatty acid methyl ester (FAME) was calculated through $^1H$ NMR analysis. The investigation on catalyst loading, temperature, time and reusability illustrated that these ceria impregnated NaZSM-5's were found to be selective, recyclable and could yield biodiesel at low temperature with low methanol to oil ratio due to the presence of both Lewis and Bronsted basicity. Hence, from the above study it is concluded that ceria impregnated ZSM-5 could be recognized as a potential catalysts for biodiesel production in industrial processes.

• Tribology and Lubricants
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• 제15권1호
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• pp.108-115
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• 1999

The electrical and frictional properties of oil-impregnated sintered-metal bearing (OSB) and herringbone-grooved fluid bearing (HFB) with varying loads and speeds were measured. OSB shows very good performance up to 20,000 rpm and 0.05 N, and HFB successfully works up to 35,000 rpm and 0.05 N. From the endurance tests on start-stop and continuous operation, it was confirmed that those bearings could be mass-produced fur use on scanner motor in a laser scanner unit.

• Applied Chemistry for Engineering
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• 제9권5호
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• pp.726-728
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• 1998

Oil-impregnated nylons were synthesized by anionic polymerization of ${\varepsilon}$-caprolactam in the presence of mineral oils. Reaction rate and molecular weight of the product were not significantly affected by the addition of oils less than 8 phr. Physical properties such as elongation and notched impact strength were improved by the addition of oil, on the other hand hardness and tensile stress at break were slightly decreased. Oil-impregnated nylon with an oil content of 6 phr showed a minimum friction coefficient, which is only 32% compared to a friction coefficient of nylon 6 without oil.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제37권5호
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• pp.625-630
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• 2013

The friction behavior of a 60-${\mu}m$-thick anodic aluminum oxide (AAO) film having cylindrical nanopores of 45-nm diameter was investigated as a function of impregnated oil viscosity ranging from 3.4 to 392.6 cSt. Reciprocating ball-on-flat sliding friction tests using a 1-mm-diameter steel ball as the counterpart were carried out with normal load ranging from 0.1 to 1 N in an ambient environment. The friction coefficient significantly decreased with an increase in the oil viscosity. The boundary lubrication film remained effectively under all test conditions when high-viscosity oil was impregnated, whereas it was easily destroyed when low-viscosity oil was impregnated. Thin plastic deformed layer patches were formed on the worn surface with high-viscosity oil without evidence of tribochemical reaction and transfer of counterpart material.

• Journal of the Korean Society of Food Science and Nutrition
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• 제26권6호
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• pp.1028-1032
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• 1997

Low-temperature crystallization method silver nitrate-impregnated silicic acid column chromatography were applied for the isolation of pure $\alpha$-linolenic acid(ALA) from perilla seed oil. ALA or 78% in purity(HALA; yield, 83%) was obtained from the fatty acid mixture(ALA, 65.7%) derived from perilla oil by the low-temperature crystallization method, when the mixture was frozen at -8$0^{\circ}C$ for 210min. ALA over 90% in purity(yield, 71%) was also obtained from HALA ethyl esters(ALA, 78%) by the silver nitrate-impregnated silicic acid column(100cm$\times$10cm, i.d.) chromatography. In addition, the silver nitrate-impregnated silicic acid could be semipermanently used for isolation of ALA, because $Ag^{+}$ ion was not dissociated from the stationary phase.

• Proceedings of the KIEE Conference
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1216-1217
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• 2008

A description is given of impregnated silicone rubber used in accessories for application on outdoor termination (EB-A). We examines the effects of swelling and mechanical/electrical characteristics for impregnated silicone rubber to develop slip on type sleeve of silicone material. There are semi-conductive silicone rubber and insulation silicone rubber. This examination is monitored as a function of the viscosity and temperature of oil during 30hr. We measure elongation at breakdown and AC breakdown strength and volume resistivities of the oil-impregnated silicone rubbers. The measured values are compared to initial value as function of stress relief cone.

• Journal of the Korean Society for Precision Engineering
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• 제19권3호
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• pp.114-122
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• 2002

Electric conductivities, mechanical properties and friction properties were investigated far graphite-nylon composites impregnated with oil. Specific resistivity of composites containing oil from 2% to 6% were in the range of $10^7 ~10^6 \ohm$ cm, which were applicable for anti-static purpose of composites improved by the impregnation of graphite with 2%. Improvement in the impact strength and friction properties of graphite/nylon composites was achieved by the impregnation of oil. The coefficient of friction of the composites containing graphite from 2% to 4% and oil with 2 - 4% showed much loller than that of virgin nylon. Also the abrasive wear of the oil impregnated graphite composites were decreased about 1/3 - 1/10.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1512-1519
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• 2013

Oil-impregnated paper is a major type of insulation used in oil-filled converter transformers for both traditional and new energy systems. This paper presents and analyzes the results of the experiment conducted on the electrical aging of oil-impregnated paper under AC-DC combined voltages using the pulsed electro-acoustic (PEA) technique. The formation and dynamics of space charge affected the performance of insulation material. The electrical aged oil-paper insulation was obtained through electrical aged experiments under the voltages. Based on the PEA technique, measurements were carried out when the oil-paper insulation system was subjected to different stressing and aging times. The space charge dynamics in the bulk of the oil-paper insulation system with different aging times were measured and analyzed. Characteristic parameters such as the total charge injection amount, the total charges of fast moving and slow moving, and the distortion factor of electric field were calculated and discussed. Results show that the longer electrical aging time, the more charges trapped in the bulk of aging sample. It leads to larger distortion factor of electric field in the bulk of aging samples and accelerate degradation of oil-paper insulation under AC-DC combined voltages.