• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.38-42
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• 2003

In a pressurized water reactor, radioactive corrosion products (CRUD) in primary coolant system are one of the major sources for the occupational radiation exposure of the personnel in a nuclear power plant. Through the recent trend of long term fuel cycle in a nuclear power plant, radioactive corrosion products deposited in reactor core for a long time are also the cause of Axial Offset Anomaly (AOA) having an effect on reactor power by the hideout of boron. CRUD consist primarily of magnetite, nickel ferrite, cobalt ferrite, and so on. They have the characteristic of strong magnetism. Therefore it is peformed the conceptual design to develop the filter which removes the CRUD by magnetic field that is generated by an arrangement of permanent and electric magnets. Contrary to the conventional filter, the proposed filter does not interrupt the fluid flow, so there is little pressure drop and it can be used continuously. It is expected to be applied as one of the technologies for removal of the CRUD.

• Journal of the Korean Institute of Gas
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• v.15 no.6
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• pp.28-33
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• 2011

The purpose of this paper analyzes and studies to improve the failure cases on the computer that one of electronic control elements for engine in liquified petroleum gas vehicle. The first case, it certified the non-starting phenomenon of engine that it's electronic control unit didn't control the fuel for idle speed actuator because of no given action signal in slow-cut solenoid valve. The second case, it knew the bad condition phenomenon of engine and back-fire by the wire melting of ignition coil and firing of transistor being inside ECU. The third case, it certified the action stoping phenomenon of engine and malfunctioning signal for engine ECU because of leakage of current and an excess current by moisture inflowing inside ECU curcuit plate. Therefore, it is thought that will elevate the durability and reliability of engine computer throughout procure of quality.

• Conservation Science in Museum
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• v.11
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• pp.9-16
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• 2010

The National Chuncheon Museum has carried out a conservation process in order to prevent corrosion of the seated iron Śākyamuni Buddha statue from Goreyo Dysnasty for its exhibition. Before the conservation process, the surface of the artifact showed exfoliation and the artifact was damaged from rear to legs so exhibition was impossible. Therefore a process to get rid of pollution and to reinforce and protect the artifact was carried out. Before the reinforcing process, a basic test was carried out using micro crystalline wax type with reference to foreign and domestic experiment results. As a result, as wax(in xylene) 5wt% of Dongnam petrochemical Ltd. showed no efflorescence and little change in surface color and was convenient to use, it was chosen as a reinforcing agent and used to suppress corrosion. For the restoration of damaged parts, an internal support was made and used with an epoxy resin, allowing removable restoration, thus increasing effectiveness for exhibition.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.142-147
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• 2009

The influence of graphitization of carbon support on the electrochemical corrosion of carbon and sintering of Pt particles are investigated by measuring $CO_2$ emission at a constant potential of 1.4 V for 30 min using on-line mass spectrometry and cyclic voltammogram. In comparison to commercial Pt/C (from Johnson Matthey), highly graphitized carbon nanofiber (CNF) supported Pt catalyst exhibits lower performance degradation and $CO_2$ emission. As the more carbon corrosion occurred, the more prominent changes were detected in electrochemical characteristics of fuel cell. This indicates that the carbon corrosion affects significantly the fuel cell durability. From the observed results, CNF is considered to be more corrosion resistant material as a catalyst support. However, CNF shows higher aggregation of Pt particles under repeated cyclic voltammetry between 0 and 0.8 V where the carbon corrosion is not initiated.

• Journal of Ocean Engineering and Technology
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• v.11 no.2
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• pp.57-69
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• 1997

The objetive of this study is to compare the mechanical proprties of 6000 series Al-Mg-Si aluminum alloy (AC120) with 5000 series Al-Mg aluminum alloy (TG25), and to investigate the influence of corrosion solution for fatigue life. Comparing of TG25 and AC120 alloy sheets, TG25 alloy sheets showing higher plastic ratio and total elongation have better formability than AC120 alloy sheets. The hardness of nugget area was a little higher than that of base metal area. Also, grain coarsening was observed in HAZ(Heat Affected Zone). In a corrosion fatigue experiment, the fatigue life decreased as concentration increased, when a dipping time was constant. The life decreased as dippling time increased, when a concentration was constant.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.3 s.10
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• pp.143-150
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• 2003

Recently, The corrosions of reinforced concrete structures are severe problems of economical social effects. PE-coated bars protecting from corrosion and enhancing durability of reinforced concrete structures are testified to evaluate structural properties. Tests are verified by comparative bending tests of the three type materials of epoxy coating, without coating and pe-coating. Load-deflection relations ate superior in pe-coated bar than any other materials(bare bar and epoxy bar). These are proved bonding properties enhancement by using cement powder.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.67-70
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• 2011

해안에 위치한 철근콘크리트 구조물 및 사회 간접 시설물들은 염해피해에 대한 우려가 있다. 염해피해로 인한 철근의 부식현상이 발생하면 철근과 콘크리트 부착성능의 저하로 인한 부재의 내력감소를 가져 올 수 있다. 따라서 본 연구에서는 염해부식이 진행되어 콘크리트와 철근간의 부착 및 비부착 여부에 따른 성능을 확인하기 위하여 완전 비부착된 보-기둥 접합부를 철근부착용 고무튜브를 이용하여 제작하였다. 제작된 실험체로 준정적 반복횡하중을 이용한 실험을 통해 성능평가를 수행하였다. 비부착된 보-기둥 접합부의 비선형 해석을 하기 위해 4절점 래티스 모델로 개선하여 적용하였다.

• Korean Journal of Heritage: History & Science
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• v.53 no.1
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• pp.24-33
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• 2020

In excavated bronze artifacts, corrosion products of various shapes and colors are observed due to multiple corrosion factors coexisting in the burial environment, and these corrosion products can constitute important data not only in terms of long-term corrosion-related information, but also in connection with preservation of artifacts. As such, scientific analysis is being carried out on the corrosion layer and corrosion products of bronze artifacts, and the corrosion mechanism and the characteristics of corrosion products elucidated, which is essential for interpreting the exposed burial environment and its association with corrosion factors inside the burial environment. In this study, after classifying excavated bronze artifacts according to alloy ratio and fabrication technique, comprehensive analysis of the surface of corrosion artifacts, corrosion layer, and corrosion products was carried out to investigate the corrosion mechanism, formation process of the corrosion layer, and characteristics of corrosion products. The study designated two groups according to alloy ratio and fabrication technique. In Group 1, which involved a Cu-Sn-Pb alloy and had no heat treatment, the surface was rough and external corrosion layers were formed on a part, or both sides, of the inside and the outside, and the surface was observed as being green or blue. α+δ phase selection corrosion was found in the metal and some were found to be concentrated in an empty space with a purity of 95 percent or more after α+δ phase corrosion. The Cu-Sn alloy and heat-treated Group 2 formed a smooth surface with no external corrosion layer, and a dark yellow surface was observed. In addition, no external corrosion layer was observed, unlike Group 1, and α corrosion was found inside the metal. In conclusion, it can be seen that the bronze artifacts excavated from the same site differ in various aspects, including the formation of the corrosion layer, the shape and color of the corrosion products, and the metal ion migration path, depending on the alloy ratio and fabrication technique. They also exhibited different corrosion characteristics in the same material, which means that different forms of corrosion can occur depending on the exposure environment in the burial setting. Therefore, even bronze artifacts excavated from the same site will have different corrosion characteristics depending on alloy ratio, fabrication technique, and exposure environment. The study shows one aspect of corrosion characteristics in specific areas and objects; further study of corrosion mechanisms in accordance with burial conditions will be required through analysis of the corrosive layer and corrosive product characteristics of bronze artifacts from various regions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.681-686
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• 2017

Degradation is commonly observed in field-aged PV modules due to corrosion of the photovoltaic ribbon. The reduced performance is caused by a loss of fill factor due to the high series resistance in the PV ribbon. This study aimed to mitigate the degradation by corrosion using five sacrificial anodes - Al, Zn and their alloys - to identify the most effective material to mitigate the corrosion of the PV ribbon. The corrosion behavior of the five sacrificial anode materials were examined by open circuit potential measurements, potentiodynamic polarization tests, and galvanic current density and potential measurements using a zero resistance ammeter. Immersion tests for 120 hours were also conducted using materials and damp heat test tests were performed for 1500 hours using 4 cell mini modules. The Al-3Mg and Al-3Zn-1Mg sacrificial anodes had a low corrosion rate and reduced drop in power, making then suitable for long-term use.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.2
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• pp.236-242
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• 1989

In order to investigate the effects of hot corrosion on the creep rupture properties and creep life of 304 stainless steel being used as tube materials of heavy oil fired boiler, the creep rupture tests were carried out at temperature 630.deg.C, 690.deg.C and 750.deg.C in static air for the specimens with or without coating of double layer corrosives according to the new hot corrosion test method simulating the situation commonly observed on superheater tubes of the actual boiler. The double layer corrosives are 85% V$_{2}$O$_{5}$ + 10% Na$_{2}$So$_{4}$ + 5% Fe$_{2}$O$_{3}$ as the inner layer corrosive being once melted at 900.deg. C and crushed to powder, and 10% V$_{2}$O$_{5}$ + 85% Na$_{2}$SO$_{4}$ +5% Fe$_{2}$O$_{3}$ as the outer layer corrosive. As results, in the specimen coated with the double layer corrosives, the rupture strength was extremely lowered and showed a large difference each other. The rupture ductility also lowered remarkably as a result of the brittle fracture mode due to hot corrosion. These results indicate that hot corrosion could essentially alter the creep fracture mechanism. From the metallographic observation, it was clarified that the rupture life of 304 stainless steel subjected to hot corrosion was chiefly determined by the behavior of the aggressive intergranular penetration of sulfides.des.