• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.1
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• pp.21-30
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• 1999

The research for retecting of insulating deterioration in transforrrer has been studied from long ago and the analysis rrethod of combustible gas which is included in insulating oil has been used Recently the spreading effect of the accident is larger than before because of high voltage and large capacity, so on-line detecting system is needed and the study for the estimation of partial discharge signals location has begun. This thesis is the study for the sermating noise signal that is the greatest problem in ultrasonic signal measurement which is one of the method of estimation of partial discharge signals location. Because we can measure the number and location of signal, it is rossible to distinguish between the signal of partial discharge and the external noise. Therefore, we can devolop the credibility of detecting of insulating deterioration in transformer.former.

• Journal of Nutrition and Health
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• v.15 no.4
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• pp.277-289
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• 1982

Because of a high degree of unsaturation of perilla seed oil vitamin E deficiency can be produced in chicks by using this particular oil diet. It is therefore convenient to use this oil for elucidating more detailed function (s) of vitamin E. The present study was undertaken to investigate the nutritional and pathological aspects both of high PUFA and of low vitamin E in the diet eventually to elucidate the function(s) of vitamin E. The present study examines the relationships between PUFA, vitamin E and Se in the experimental diets by measuring vitamin E levels both in serum and in liver and activities of SGPT and SGOT and by examining electron micrographs of the chick hepatocytes. Vitamin E concentrations in serum and liver responded to dietary treatments. Serum levels of vitamin E were more affected than those in liver, the values of groups IV(15% fat,- Vit.E) and V(15% fat,-Vit E,-Se) were significantly lower than those of groups I (5% fat) and 111 (15% fat) with P/S ratio of 1. The activities of SGOT and SGPT were found not to be different significantly among different diet groups. Electron microscopic observations of the chick hepatocyte revealed degeneration of mitochondria and appearance of vesicles in the cytoplasm of groups fed diets high in PUFA and deficient in vitamin E alone or deficient in both vitamin E and Se. In the same group pyknotic nuclei and deterioration of the sinusoidal border, showing diminution in microvilli were also observed. More detailed studies concerning biochemical aspects should be carried out by using radioisotopes both in the in vitro and in vivo systems and morphological study should have a focus on the changes in nucleus which seems already suggestive in the present observation.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.202-206
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• 2006

The oxidation stability of fish oil containing omega-3 polyunsaturated fatty acids (PUFAs), which is very susceptible to oxidative deterioration, needs to be improved before it can be successfully applied to functional foods. The antioxidant activities of 17 species of materials in anchovy oil (AO) were compared and a potent antioxidant was determined to improve the shelf-life of refined AO. Antioxidant activities of the 0.05% (w/w) materials in AO were compared against control during storage at $30^{\circ}C$ for 10 days. While no antioxidant effect was shown in alpha tocopherol against control, 3 species of grapefruit seed extracts (GSEs), astaxanthin (AX), soybean lecithin, and green tea extract showed good antioxidant activities. Especially, GSE B, GSE C, and AX showed significantly high peroxide inhibitory activities (PIAs) of $16.2{\pm}2.1$, $20.{\pm}3.5$, and $17.7{\pm}3.5%$, respectively, after the 4th day (p<0.01). Radical scavenging activities (RSAs) of GSE B, GSE C, and AX were $85.1{\pm}0.8$, $95.3{\pm}0.3$, and $85.9{\pm}0.8%$, respectively. Correlation between PIAs and RSAs was high ($R^2=0.926$) in GSE B, GSE C, and AX. Therefore, we concluded that one of the main antioxidative mechanisms of GSEs and AX must operate through an RSA pathway. The $RC_{50}$ (concentration required for 50% reduction of 1,1-diphenyl-2-picryl-hydrazyl, DPPH) of GSE C was $258\;{\mu}g/mL$.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1114-1123
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• 2015

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oil-paper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ. Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.2
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• pp.33-40
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• 2013

Powdered additive or organic filler is used to improve paperboard thickness and to reduce drying energy consumption in the Korean paperboard industry. In a previous study, we identified alternative non-lignocellulosic resources to wood powder, specifically brewers grain and oil palm frond powders, and verified that these materials had the same functionality as wood powder. The main drawback of the use of such additives, including both lignocellulosic and non-lignocellulosic resources, is the deterioration in paperboard strengths. Therefore, we carried out a basic study on the surface modification of brewers grain and oil palm frond powders to improve the strengths of paperboard. Surface modification was performed using various types of cationic and oxidized starches. The streaming current and zeta-potential of the two non-lignocellulosic powders were measured and CLSM images were taken to assess the surface modification.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.539-546
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• 1996

The physical condition of rapeseed delivered to fat industry plants plays a significant role in the formation of the qualitative features of the raw material for oil production and, consequently , of the oil itself. Rapeseed is stored in silos , frequently for months, before it is subjected to processing. During the long storage, the conditions of the seed cover is very important, as the seed cover provides natural protection of the seed against the effect of the environment. Seeds with damaged seed cover are more easily affected by mildew, and the rate of chemical processes. Deteriorating the quality of oil contained in the cotyledons is faster in such seeds. Cracked seed covers facilitates also the growth and development of microorgaism. So as rapeseed damage occurring inthe course of harvest and the post-harvest processing have a negative effect of the quality and quantity of oil the sees contain. The study presented here was aimed at examining the typical process of purcha ing and handling of rapeseed in fat industry plants, in the aspect of the occurrence of mechanical damage to the seeds. Special attention was paid to the condition of rapeseed immediately after combine harvesting : next , the successive stages of technological handling of the seed were examined. observing the operation parameters of the particular machinery and equipment in order to identify those operations which caused deterioration in the quality of the material (sees). Seed samples were taken successively from the following the hopper, prior to cleaning , after cleaning , prior to drying , after drying, from dry rape silo. The total level of damage increased through the handling. The content of unusable contaminants had the tendency to decrease in the successive operations. though the actual values still exceeded levels permitted by standards. The study allow to indicate the operation fo postharvest technological process, which cause the most seed damage as well as gave quantita ive description of the losses occurred.

• Journal of Conservation Science
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• v.6 no.1 s.7
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• pp.71-78
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• 1997

Oil painting shows a wide variety of damages due to differentcohesiveness between materials and different responses to temperature and humidity. The deforming flatness of canvas is a major cause of deterioration. The heat, pressure and moisture, and classical materials which had been traditionally used to correct the deformation of supports have caused damages to the paintings. In modern restoration of paintings, new methods have been developed to avoid the use of such potentially harmful elements. In this paper the correcting of deformed support with the use of low-pressure table, deformation correction frame and new materials, which has been developed both to protect the works and to maximize the effect of restoration.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1116-1122
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• 2009

As a result of this study, we reached the following conclusions. With appropriate setting of oil pressure and flow rate, it operated same rotation speed with existing cooler by electrical transmission. In initial operation, a temperature of a cold storage is lower rapidly. As an internal temperature of a cold storage is lower, a decreasing rate of temperature is lower. As a result of comparing the both type, the cooler of oil pressure type showed the following results. The decreasing rate of temperature was more faster and shorter operating time was more shorter than existing cooler of electric type. The actual case of a cold storage, the cooler of oil pressure type can prevent quality deterioration and decrease power consumption. As an internal temperature of a cold storage is lower, power consumption increased rapidly, the oil pressure type showed lower power consumption. COP of two of these types decreased continuously as the internal temperature of a cold storage being reach setting temperature, and that of oil pressure type showed higher amount about 25%. As a setting temperature is lower, the number of refrigerator's operating times are less and operating time is longer, so power consumption is increased in the maintenance of a cold storage's internal temperature, power consumption of hydraulic type showed lower amount about 21~25% in two of these types.

• Journal of Biosystems Engineering
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• v.33 no.6
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• pp.379-383
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• 2008

A CRDI diesel engine used to commercial vehicle was fueled with diesel fuel and 20% biodiesel blended fuel (BDF 20%) and tested at the Seoul-10 mode for 150 hours. Engine dynamometer testing was completed at regularly scheduled intervals to monitor the engine performance and exhaust emissions. To check the engine parts (valve, injector), the engine was inspected after 150 hours running test. It was concluded that there was no unusual deterioration of the engine, or the changes in engine power (below 1.9%), smoke (below 4.1%), NOx (below 3.7%) and durability characteristics in spite of operation of 150 hours run with BDF 20%. The difference of kinetic viscosity for engine oil (before and after durability testing) was below 0.19% at $100^{\circ}C$.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.465-466
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• 2002

In any mechanical system consisting of gears, shafts and/or bearings, the majority of metallic particles deposited into and carried by the lubrication system originate from the deterioration of oil-wetted working surfaces, even in proper lubrication system, due to failure mechanism (s) such as wear, fatigue and fretting corrosion. Determination of the point at which transition from normal to abnormal or to actual damage occurs has become a focus of attention in research activities for years, because it has been recognized that reliable, economic operation can be achieved through appropriate preventative measures. Known collectively from 'all size wear debris analysis' as early failure detection, the methods of testing for damage differ considerably, range from a micron or a submicron size debris analysis to Magnetic Chip Detector (MCD) ferrous debris analysis. This paper will be focused on the utilization of the low-cost analysis techniques for evaluation of industrial machinery condition.