• Corrosion Science and Technology
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• v.7 no.1
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• pp.13-15
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• 2008

Aiming at the corrosion circumstances and corrosion prevention needs of downhole oil tubes, series protective coatings for downhole oil tubes have been developed in the authors' laboratory, including a baked type coating YG-01 and an air curing type coating YG-03, etc. The performance investigation of the coatings has been done for testing their corrosion resistance, mainly including salt fog test, immersion test in oil-field waste water and various acid solutions, high temperature and high pressure test in alkali solution or $H_2S/CO_2$ environment, as well as some other performances. The investigation results show that oil tube anti-corrosion coatings developed here can endure over 4000 hrs salt fog test, over 1000 hrs immersion in various acid solutions at room temperature and in boiling oil-field waste water. In addition, the coatings can keep intact after experiencing test in alkali solution under 70 MPa pressure at $150^{\circ}C$ for 24 hrs, and in simulative sour gas environment under the total pressure of 32 MPa ($P_{H_{2}S}=3.2MPa$, $P_{CO_{2}}=3.2MPa$) at $90^{\circ}C$ for 168 hrs, which show that the coatings can be used for corrosion prevention in downhole environments with specific high temperature and high pressure, such as sour gas wells. The other testing results show the oil tube protective coatings have excellent comprehensive performance.

• Journal of radiological science and technology
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• v.6 no.1
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• pp.43-67
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• 1983

In order to increase the sensitivity of the photographic emulsion, one of the chemical sensitizers hydroxymethane sulfonic acid sodium salt(HMS) was applied through the chemical ripening process and following four types of emulsion were prepared. Their grain sizes were determined through the electron microscope. The ranges of average grain sizes were $0.05-0.40{\mu}m$ for silver chlorobromide emulsion of low sensitivity $0.10-0.45{\mu}m$ for the silver chlorobromide emulsion of medium sensitivity, $0.60-1.05{\mu}m$ for the silver iodobromide emulsion of high sensitivity, and $0.90-1.55{\mu}m$ for the ammonical silver iodobromide emulsion of high sensitivity. Through the reduction sensitization with HMS, they showed significant sensitivity enhancement by the increment of HMS concentration above pH 5.5 and pBr 3.0. Required sensitivity was obtained above pH 6.2 and pBr 3.3 when sulfur and gold sensitization were applied. Fog formed along the reduction sensitization was successfully prevented by the addition of 5.5-dimethylhydantion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.117-120
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• 1996

In this paper, It is tested by spraying the spoiled liquids on the materials to prove the process of tracking under the various environments. Our experiments ware examined by setting the materials in the spray chamber, and by spraying the distilled water(DW), the city water(CW), the underground water(UW), the artificial acid rain(AR) and the salt water(SW) in applied voltage 3-6[KV]. As the result, the time of tracking breakdown became shorter in the order of DW < CW < UW < AR < SW. XLPE was eroded and its anti-bracking property was very strong, but that of PVC sheath was week. Especially it was confirmed that spraying by AR and SW on the PVC sheath had a serious effect on the lifetime of cable by the tracking breakdown.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1449-1451
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• 2002

A developed 800kV class composite hollow insulator for $SF_6$ Gas Insulated Switchgear (GIS) was tested as to insulation with their surfaces contaminated. The wet power frequency withstand voltage of the silicone rubber housing was about 135kV at an equivalent salt deposite density of $5kg/m^2$, to sufficiently satisfy the required performance. According to IEC 60507, the salt fog withstand voltage was measured at 565kV, and the highest measured leakage current was below 0.2mA. Therefore, it was clarified that the composite hollow insulator has sufficient insulation performance even when it is contaminated on the surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1132-1141
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• 2004

The waveforms of the leakage currents for the surface discharge according to the degree of salt contamination and the variation of environmental condition on the EPDM polymer insulators, were shown in this paper. The variation phenomena of fundamental wave, 3rd and 5th harmonic waveforms were also shown from the beginning of the applied voltage and to the flashover voltage. To develop the technique of percentage contamination degree of EPDM polymer insulator according to the variation of environmental condition, the distortion degree of 3rd and 5th harmonic wave to the fundamental wave was utilized through the spectrum analysis for the waveforms of leakage current in the simulation of salt and fog test. The fact that distortion degree % of 3rd and 5th harmonics for fundamental wave is a necessary indicator for the assessment of contamination degree for the polymer insulators, was known.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1605-1607
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• 1999

Silicone rubber have presently been using in large number for a variety of outdoor HV applications. Silicone rubber have the properties of low surface energy and are able to retain its hydrophobicity or water repellency, thereby suppress the leakage current in the present of moisture and contamination. In this paper, we investigated the recovery characteristics of silicone rubber by measuring the leakage current under salt-fog.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.203-206
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• 2001

Since th three sides of korea peninsula are surrounded by the sea, electric apparatus are greatly contaminated by the salt generated by the typhoon, seasonal wind, sea wind and sea fog. This contamination causes electric power apparatus to fail. Thus in this paper, we investigated to influence upon electrical properties of outdoor insulators with non-uniformity contamination in the experimental condition because The contamination of outdoor insulator highly depended wind property In the service condition, insulator was not uniformly contaminated. From the flashover test for the 254 mm suspension insulator, we could determine the influence non-uniform contamination on the electrical property of insulators. Through the experiment, we convinced to occur flashover from non-uniform contamination region of outdoor insulator. Contaminated area and pattern has a close relationship with the electrical properties of outdoor insulator.

• Electrical & Electronic Materials
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• v.9 no.4
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• pp.344-350
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• 1996

Tracking is one of the biggist problems to be overcome in polymeric materials for outdoor insulators. But It can be decreased with the addition of filler such as alumina trihydrate (ATH). In this paper, the tracking of surface and evaluation of insulating ability at silicone rubber is investigated, using the salt fog test. At initial state, the peak leakage current and numbers by dry band arcing is increasing with increasing the filler level, but at aged state decreasing at high concentration filler samples. This is because the roughness of the surface may contribute to the increase in peak leakage cur-rent and numbers. As increasing the filler level, the insulating ability of materials is higher and weight loss is decreased. The mechanism of insulating failure is occurred by the erosion than the tracking and the erosion caused weight loss of 2 g.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1499-1501
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• 1994

This paper studies on the outdoor field test facilities which are established for weather-resist and mechanical-resist property teat of composite insulator. We have established measuring and data acquisition system for various test conditions -leakage current, temperature, humidity, wind direction, wind velocity and rainfall. The merry-go-round test and salt fog test have been studied in order to evaluate non tracking property of rubber material. Especially we have checked the relationship between hydrophobicity and outdoor exposure degree by contact angle measurement.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1933-1935
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• 2000

In this paper, it was tried to find out the minimum measurement range in the diagnosis of insulators using thermal image camera, for the purpose, leakage currents and thermal images were observed simultaneously for the insulators of which surface had been artificially polluted by salt fog. As a result. the surface temperature was increased with leakage currents. Also, the results of AC breakdown tests for the insulator of which temperature rise was more than 1 $^{\circ}C$ showed to be bad. Therefore, through the study on the relationship between leakage current, temperature rise and AC breakdown voltages, the diagnosis of the insulator in site would be possible using the thermal image camera.