• Journal of Welding and Joining
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• v.11 no.3
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• pp.61-74
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• 1993

The cause of corrosion failure found in structures or various components operating in severe corrosive environment has been attributed to stress corrosion cracking(SCC) which is resulting from the combined effects of corrosive environments and static tensile stress. Cathodic protection is an electrochemical method of corrosion control that is widely used in marine environment and primarily on carbon steel. A number of criteria are used to determine whether or not a structure is cathodically protected. In practice, -0.8V versus Ag/AgCl is the most commonly used for marine structures. This paper showed the combined effects of cathodic potential and slow, monotonic straining on the tensile ductility and fracture morphology of parents and friction welded joints for SM45C, SCM440 and SM20C steels in syntheic sea water(S.S.W.,pH:8.2). For the parent materials in cathodic potentials, the higher tensile strength is, the more susceptible SCC is. And the welded HAZ is more susceptible than the parent materials.

• Corrosion Science and Technology
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• v.21 no.5
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• pp.372-380
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• 2022

The external corrosion control of buried pipes can be achieved by a combination of coatings and cathodic protection to maximize effectiveness. One of the factors affecting cathodic protection is the environmental soil conditions. Because soil is a kind of electrolyte, the environmental conditions of soil may be changed by the atmospheric environment. Therefore, in this study, changes in environmental soil factors by atmospheric environmental factors were monitored. In cathodic protection, on-potential and off-potential were measured from December 2021 to July 2022. The effects of external environmental factors and soil environmental factors on cathodic protection were analyzed. Changes in outdoor temperature affected soil temperature, and soil conductivity had a proportional relationship with soil humidity, but outdoor humidity and precipitation did not significantly affect humidity and conductivity of the soil. In contrast, in cathodic protection, the on-potential was affected by temperature, humidity, the conductivity of the soil, and the anode used, but the off-potential was little affected by these factors.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1994.06a
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• pp.40-41
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• 1994

본 연구에서는 윤활유에 해수가 혼입된 유화유중에서 음극방식에 의한 선박용 베어링 합금재의 침식-부식억제에 관한 연구를 위하여, 초음파 진동장치의 캐비네이션 발생장치에 의해 선박용 베어링 합금재의 캐비네이션 침식-부식방지를 위해 음극방식(Cathodic protection)실험을 실시하였다. 이실험을 토대로 하여 해수의 혼입에 따른 유화유중에서 음극방식에 의한 베어링 합금재의 침식-부식억제효과를 구명하고자 한다.

• Corrosion Science and Technology
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• v.6 no.6
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• pp.308-310
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• 2007

The owner of underground metallic structures (gas pipeline, oil pipeline, water pipeline, etc) has a burden of responsibility for the corrosion protection in order to prevent big accidents like gas explosion, soil pollution, leakage and so on. So far, Cathodic Protection(CP) technology have been implemented for protection of underground systems. The stray current from DC subway system in Korea has affected the cathodic protection (CP) design of the buried pipelines adjacent to the railroads. In this aspect, KERI has developed a various mitigation method, drainage system through steel bar under the rail, a stray current gathering mesh system, insulation method between yard and main line, distributed ICCP(Impressed Current Cathodic System), High speed response rectifier, restrictive drainage system, Boding ICCP system. We installed the mitigation system at the real field and test of its efficiency in Busan and Seoul, Korea. In this paper, the results of field test, especially, distributed ICCP are described.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3172-3174
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• 2000

It is necessary to collect and analyze the corrosion date to control the underground metallic structures systematically. It can be possible to predict the remaining life of underground metallic structures. In this paper we describe the life prediction technology of cathodic protection systems and underground metallic structures without a cathodic protection system.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.249-252
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• 2002

Recently, the advanced countries are using the corrosion monitoring system in a chemical plant and an oil tank in order to protect the corrosion because it leads to a big accident, pollution of soil. and lose of money Generally. the owners of the facilities adopt CP(Cathodic Protection) systems to protect the corrosion also. However, a CP system for oil tank was not considered in Korea Moreover they didn't adopted a corrosion monitoring system. In this paper, we have been developed not only the remote automatic corrosion monitoring but also the remote corrosion control system using the high efficiency CP rectifier. This results should be used to operate the CP system effectively and economically. And also it will be possible to extend the expectation life of the Oil tanks.

• Journal of Plant Biology
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• v.36 no.4
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• pp.307-312
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• 1993

In germinating pea, contents of enodgenous polyamine in the leaf and stem were determined, and protein content, peroxidase activity and pattern of isozymes were examined in the leaf treated with polyamines. During growth of the pea for 14 days in light condition, the polyamines in leaf and stem showed the highest level at the 5th day, and were decreased rapidly at the 7th day, kept almost constant level since then. The putrescine level was relatively higher than those of spermidine and spermine, and cadaverine was also detected. On the other hand, in the leaf treated with spermine (0.01 mM) protein content increased about 250% than that of the control, the peroxidase activity increased ore than 100% in spermine of 0.01 mM and 0.1 mM. In treating with putrescine of 0.1 mM the pattern of peroxidase isozyme appeared 4 new cathodic bands (pI 4.8, 5.6, 5.9 and 6.8) compared with the control, the clear cathodic bands (pI 5.6, 5.9, 6.4 and 6.6) were also observed in spermine of 0.1 mM. These results suggest that polyamines were important factor in the differentiation of pea at the early stage of germination.

• Proceedings of the KIEE Conference
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• 2000.11d
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• pp.727-728
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• 2000

The Cathodic Protection system which is usually applied to marine metallic structures in domestic is Sacrificial Anode Method. In general. low efficiency rectifiers are using in the field of Cathodic Protection. These rectifiers are not only low efficiency but also manual type which is not able to control remotely. In this paper we describe the high efficiency rectifier used the high speed switching method for optimum corrosion control of marine metallic structures.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3130-3132
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• 2000

The Cathodic Protection system which is usually applied to marine metallic structures in domestic is Sacrificial Anode Method. In general, low efficiency rectifiers are using in the field of Cathodic Protection. These rectifiers are not only low efficiency but also manual type which is not able to control remotely. In this paper we describe the high efficiency rectifier used the high speed switching method for optimum corrosion control of marine metallic structures.

• Corrosion Science and Technology
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• v.14 no.1
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• pp.12-18
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• 2015

Since the operation period of nuclear power plants has increased, the degradation of buried pipes gradually increases and recently it seems to be one of the emerging issues. Maintenance on buried pipes needs high quality of management system because outer surface of buried pipe contacts the various soils but inner surface reacts with various electrolytes of fluid. In the USA, USNRC and EPRI have tried to manage the degradation of buried pipes. However, there is little knowledge about the inspection procedure, test and manage program in the domestic nuclear power plants. This paper focuses on the development and build-up of real-time monitoring and control system of buried pipes. Pipes to be tested are tape-coated carbon steel pipe for primary component cooling water system, asphalt-coated cast iron pipe for fire protection system, and pre-stressed concrete cylinder pipe for sea water cooling system. A control system for cathodic protection was installed on each test pipe which has been monitored and controlled. For the calculation of protection range and optimization, computer simulation was performed using COMSOL Multiphysics (Altsoft co.).