다구치 방법과 그레이 관계분석을 이용한 전기화학 수소압축기 엔드플레이트의 구조분석 및 최적화

서상덕,권원태 한국정밀공학회 2023 한국정밀공학회지 Vol.40 No.12

The Electrochemical Hydrogen Compressor is an optimal device for compressing low-pressure hydrogen to high-pressure hydrogen. It has a similar structure to the Proton Exchange Membrane Fuel Cell but operates at extremely high pressures, requiring multiple cells sealed with End Plates. The End Plate design must provide initial cell activation support, withstand maximum operating pressure within the stack, and prevent internal gas leakage. This study applies a multi-objective optimization method and grey relation analysis to determine the optimal design parameters for the End Plate based on the activation area of Dummy Cells. Finite Element Method (FEM) analysis is conducted to verify the effectiveness of the optimized End Plate design, considering the uniform pressure distribution with stacked Dummy Cells (1, 3, 6, 12). The analysis reveals that the parameters affecting the uniform pressure distribution include the End Plate design, stack sealing pressure, individual Cell design parameters, and the number of Cell stack layers.

Effect of two different calcium hydroxide paste removal techniques on apical leakage : an electrochemical study

Park, Chan-Je,Jeon, Kyung-A,Kwon, Ho-Beom 大韓齒科保存學會 2006 Restorative Dentistry & Endodontics Vol.31 No.3

본 연구의 목적은 근관내 약제로 사용되는 수산화칼슘의 제거방법이 근관충전 후 치근단 미세누출에 미치는 영향을 알아보기 위함이다. 70개의 발거된 단근치를 엔진구동형 ProFile로 근관형성한 후 수용성 수산화칼슘 제제를 1주일간 적용하고 두 군으로 나누어 각기 다른 방법으로 제거하였다. A군은 NaOCI로 근관세정만을 시행하였으며, B군은 근관형성 시 사용된 file보다 한 단계 큰 크기의 ProFile을 사용하여 근관을 재형성한 후 NaOCI로 세척하였다. 근관충전 후 전기화학적 방법으로 24일 동안 치근단 누출을 측정, 비교하였다. 본 연구의 결과 수산화 칼슘 제거를 위한 두가지 방법은 근관충전후 치근단 미세누출에 있어서 차이가 없음을 알 수 있었다. This study evaluated the effect of two different calcium hydroxide (Ca(OH)_(2)) paste removal techniques on the apical leakage of canals obturated with gutta percha cones and sealer after removing a Ca(OH)_(2) dressing using an electrochemical method. Seventy extracted single-rooted teeth were instrumented on with Profile rotary files under NaOCI irrigation. Fifty-eight canals were filled with calcium hydroxide paste, which was then removed using one of the following two techniques. In group A, calcium hydroxide was removed using only NaOCI irrigation, and in group B, the canals were re-prepared with a Profile rotary files-one size larger than the previous instrument and were irrigated with NaOCI. In both groups, the root surfaces were coated twice with nail varnish from CEJ to an area 4㎜ away from the apex after canal obturation. Apical leakage was measured using an electrochemical method for 24 days. All the specimens showed leakddffqage that increased markedly in the first three days. There was no significant difference between the two groups (p > 0.05). The effect of two calcium hydroxide paste removal techniques on the apical leakage was not different during a short period.

부식촉진시험에 의한 콘크리트 중 철근의 부식 임계 염화물량 평가

배수호(Bae Su-Ho),이광명(Lee Kwang-Myong),김지상(Kim Jee-Sang),김영상(Kim Young-Sang) 대한토목학회 2007 대한토목학회논문집 A Vol.27 No.5A

염해환경 하에 있는 철근 콘크리트 구조물의 내구수명을 평가하기 위해서는 콘크리트 중 철근의 부식 임계 염화물량 및 콘크리트의 염소이온 확산계수와 같은 재료의 정량적인 물성 파악이 필수적이다. 그러나, 이들은 콘크리트 배합비, 시멘트 종류 및 환경 조건 등과 같은 여러 요인에 의해 영향을 받는 것으로 알려져 있다. 따라서, 본 연구에서는 부식촉진시험에 의해서 콘크리트 중 철근의 부식 임계 염화물량을 평가하는 것을 목적으로 하였다. 이를 위하여 물시멘트(W/C)비 32%, 42% 및 50%에 대해서 원주형 및 각주형 콘크리트 시험체를 제작한 다음, 이들에 대해 전기화학적 방법 및 염수 건습반복법에 의한 철근부식 촉진시험을 수행하였다. 촉진시험이 진행되는 동안, 철근의 부식 개시 시기를 추정하기 위하여 시험체에 대해서 자연전위 측정에 의한 부식 모니터링을 수행하였고, 철근부식이 감지되었을 때 시험체를 피괴한 후 W/C비별로 염화물량을 평가하였다. 결론적으로, 콘크리트 중 철근의 부식 임계 염화물량은 W/C비와 부식 촉진시험 방법에 의존하며, 본 연구에 사용된 콘크리트 시험체의 임계 염화물량은 0.91~1.63 ㎏/㎥ (시멘트 중량비의 0.17~0.31%)으로 나타났다. To predict the service life of reinforced concrete structures exposed to chloride environment, quantitative measures of material properties such as the critical chloride content for corrosion of the reinforcing steel in concrete and the diffusion coefficient of the chloride ions of concrete are essential. However, it should be noted that they are influenced by several factors such as concrete mix proportions, cement type, and environmental conditions, etc. Thus, the purpose of this research is to estimate the critical chloride content for corrosion of the reinforcing steel in concrete by the accelerated corrosion tests. For this purpose, cylinder and prism concrete test specimens were made for water-cement (W/C) ratios of 31 %, 42%, and 50%, and then the accelerated corrosion tests for them were conducted by electrochemical and cyclic wet and dry salt water method. During the test, corrosion monitoring by half cell potential method was carried out to detect the time to initiation of corrosion for test specimens and its chloride content was evaluated by breaking the concrete test specimens when corrosion of the reinforcing steel in concrete was perceived. It was observed from the test results that the critical chloride content for corrosion of reinforcing steel in concrete would be dependent on both W/C ratio and the type of the accelerated corrosion test, and the critical chloride content of the concrete test specimens used in the study were found to range from 0.91 to 1.63 ㎏/㎥ (0.17~0.31% by weight of cement).

수중 경화형도료의 부식특성에 관한 전기화학적 고찰

문경만(Kyung-Man Moon),오민석(Min-Seok Oh),이명훈(Myung-Hoon Lee),이성렬(Syung-Yul Lee),김윤해(Yun-Hae Kim) 한국해양공학회 2011 韓國海洋工學會誌 Vol.25 No.2

Many protection methods such as surface coating, electric protection, or other methods have been applied to the numerous steel structures widely used in continental and marine areas to control their corrosion, which is done from an economic point of view. Most of these steel structures are primarily protected by coating methods. However, some steel piles under seawater are protected by the electric protection method, that is, either using an impressed current or a sacrificial anode method. Furthermore, environmental contamination may cause a severely corrosive environment, which, in turn, causes the accelerated corrosion of steel structures. Subsequently, coated steel structures could deteriorate more rapidly than the designed lifetime because of the acid rain caused by air pollution, etc. Therefore, a coating of marine paint exposed to seawater, that is, underwater hardening painting, is increasingly required to be fast drying as well as highly corrosion resistant. In this study, five types of underwater hardening paints were prepared with different resin series and additives. Their corrosion and water resistances were investigated using electrochemical methods such as corrosion potential, polarization curves, impedance and cyclic voltammogram measurements, etc. Even though it is generally accepted that the corrosion resistance of bare steel tends to increase with a shift of the corrosion potential in the noble direction, the corrosion resistance of a sample with a coating exhibited a relatively better tendency when it had a lower corrosion potential in this study. The corrosion current density was also decreased with a decrease in the diffusion limiting current density, which may mean that there is some relationship between corrosion and water resistance. The S sample of the ceramic resin series showed the relatively best corrosion and water resistance among those of samples, while the worst corrosion and water resistance were observed for the R sample of the epoxy resin series. The corrosion and water resistance of those samples tended to deteriorate with an increase in the immersion days, and their corrosion and water resistances were considered to be apparently improved by the types of resin and additives.

용사 도막의 내식성에 관한 전기화학적 평가

문경만(Kyung-Man Moon),신중하(Joong-Ha Shin),이명훈(Myung-Hoon Lee),이성렬(Sung-Yul Lee),김윤해(Yun-Hae Kim) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회지 Vol.34 No.4

가혹한 부식환경 하에 사용되어 지고 있는 다양한 강구조물에 대해서 많은 표면방식법이 있다. 그 중의 한방법인 용사는 다양한 강구조물의 표면방식을 위하여 비교적 최근에 개발된 유용한 방식법이다. 그러나 용사피막도 환경오염의 가속화에 따라 점차 더욱 좋은 내식성을 필요로 하고 있다. 본 연구에서는 아아크 용사에 의해서 도막두께 200㎛의 피막을 만들었으며, 피막의 종류는 순 아연,순 알류미늄, 합금피막(Al:Zn=85:15) 및 (Al:Zn=95:5)의 합금피막이었다. 그리고 이들 피막의 내식성을 해수용액에서 전기화학적인 방법으로 고찰 하였다. 순 알류미늄 피막은 다른 피막에 비해서 비교적 상당히 좋은 내식성을 보였다. 그리고 합금피막도 역시 순 아연피막에 비해서 좋은 내식성을 보였다. 특히 순 알류미늄 피막은 갈바륨 용사라고 알려진 합금피막(Al:Zn=85:15)보다 해수용액에서 내식성이 상대적으로 좋았음이 관찰되었다. 순 아연의 부식된 표면양상은 입게부식의 형태를 나타내었으나 순 알류미늄과 합금피막은 균일부식의 형태를 나타내었다. There are many surface protection methods for numerous steel structures being used under severely corrosive environment, one of them, metallizing(thermal spray) is a available protection method which is comparatively and recently developed for surrface protection of various steel structures. However coating film obtained by spraying is to be needed increasingly more good corrosion resistance due to accelerating of environmental contamination. In this study, coating films(DFT:200㎛) are performed with arc spray by wire metal and their types of films are pure zinc, pure aluminum, alloy film(Al:Zn=85:15) and alloy film(Al:Zn=95:5). And corrosion resistance of their films was investigated with electrochemical methods in seawater solution. Pure aluminum film showed a relatively somewhat good corrosion resistance compared to among those of other films and alloy films also showed a good corrosion resistance compared to pure zinc film. Especially it was observed that pure aluminum film showed a comparatively good corrosion resistance than that of alloy film named as galvarium spray(Al:Zn=85:15) in seawater solution. Morphology of corroded surface of pure zinc film appeared the pattern like intergranlar corrosion, however films of pure aluminum and alloy metal showed a general corrosion pattern.

용사된 도막의 내식성에 관한 전기화학적 평가

신중하(Joong-Ha Shin),오민석(Min-Seok Oh),이명훈(Myung-Hoon Lee),김윤해(Yun-Hae Kim),이성렬(Sung-Yul Lee),문경만(Kyung-Man Moon) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4

There are many surface protection methods for steel structures under severely corrosive environment, one of them, metallizing(thermal spray) is a available protection method which is comparatively and recently developed for surrface protection of various steel structures. However coating film obtained by spraying is to be needed increasingly more good corrosion resistance due to accelerating of environmental contamination. In this study, coating films(DFT:200㎛) are made with arc spray with wire metal both of pure zinc or aluminum and their alloy metals with some ratio(Al:Zn=85:15, 85:5). And corrosion resistance of their films is investigated with electrochemical methods in seawater solution. Pure aluminum film showed a somewhat good corrosion resistance among those of other films and good corrosion resistance was also observed at alloy films with some ratio compared to pure zinc film. Especially film of galvarium spray(Al:Zn=85:15) showed not good corrosion resistance than that of pure aluminum film in seawater solution. Morphology of corroded surface of pure zinc film appeared the pattern like intergranlar corrosion, however film of pure aluminum showed a general corrosion pattern.

팔라듐에 관한 수소저장과 팽창거동에 관한 수치해석

김세웅,황철민,장태익,정영관 한국수소및신에너지학회 2007 한국수소 및 신에너지학회논문집 Vol.18 No.3

In order to calculate the relation between the hydrogen and the hydrogen absorption metals in the atomic level, Embedded Atom Method(EAM) is recommended. In this study, we had constructed the EAM programs from constitutive formulas and parameters of the hydrogen and palladium for the purpose of predicting the expansion behavior on hydrogen absorbing in the geometric shape of hydrogen absorption metals, as palladium bars and plates. And the EAM analyses data were compared with the experiment data by using electrochemical method. As results, it is note that the expansion rate in thickness of the palladium plate model by EAM analyses is about 4 times larger than width and length, be similar to experiment results. Also, in the microscopic and macroscopic level the expansion behavior through EAM analyses show good agreement with experiment data.

Zn-Sn 합금을 이용한 강구조물의 금속용사공법 방식성능평가 연구

류화성,정동근,이한승 한국건축시공학회 2014 한국건축시공학회지 Vol.14 No.6

The purpose of this study is to evaluate the corrosion protective properties of a Zn-Sn metal spray methodaccording to the contents of Zn and Sn by a CASS test and the electrochemical theory. In the experiment, the CASStest and the electrochemical test were conducted to investigate the corrosion protective property of the Zn-Sn MetalSpray system, the Zinc galvanizing system, and the heavy duty coating system. As a result, it was confirmed that theZn-Sn (65:35) Metal Spray system had very high corrosion protective property through the electrochemicalcharacteristic as comparison with the other anti-corrosion systems and was very effective to prevent steel productsfrom corrosion. 본 연구에서는 전기화학적인 시험 및 CASS Test(염수분무시험)을 실시하여 중방식도장 시험체와 용융아연도금 시험체, Zn-Al 시험체와의 비교를 통해Zn-Sn 금속용사의 방식 성능을 평가하였다. 시험 결과, 전기화학 시험을 통하여 Zn-Sn / Zn-Al 상온금속용사 시스템 공법의 방식원리는 방식전위에 의하여 확보되는 것을 확인하였으며 강구조물의 방식 공법으로서상온금속용사 공법은 용융아연도금 공법과 중방식 도장공법과 비교하여 매우 우수한 방식성능을 가지고 있는것이 CASS 시험을 통하여 검증되었다. 특히 Zn-Sn 금속용사와 Zn-Al 금속용사를 비교해본 결과 그 방식성이 현저하게 차이가 있지는 않았으나 Zn-Sn(65:35)비율의 시험체가 가장 우수하였다. 또한 중방식 도장은손상된 부분에서 현저하게 녹이 발생하고 도막이 박리되지만, Zn-Sn / Zn-Al 상온금속용사 시스템 공법은갈바닉 희생방식에 의하여 매우 높은 부식 방지 특성을가지고 있음을 확인 하였다.

해양 환경에서 매립형 고체 기준 전극을 사용한 철근 부식 조사

카르틱수비아 ( Karthick Subbiah ),박태준 ( Taejoon Park ),이한승 ( Han-seung Lee ) 한국건축시공학회 2022 한국건축시공학회 학술발표대회 논문집 Vol.22 No.1

Reinforced concrete (RC) structures play a significant role in the construction industries. An embeddable solid-state reference electrode (ESSRE) was used to evaluate the corrosion status of steel rebar in the concrete of various cover thicknesses that exposed to the maritime environment (3.5 % NaCl) in this study. From the open circuit potential measurement (OCP), the passive state, the corrosion uncertainty, and the 90% probability of corrosion state of the steel rebars in the concrete were monitored by ESSRE. From the electrochemical impedance spectroscopy (EIS) method, severe corrosion was observed at the exposure period of 1510, 1847, 2350, and 3020 h for C10, C15, C20, and C30 concrete, respectively. The results confirm that the ESSRE can be useful to identify the corrosion occurrence and severe corrosion of steel rebar embedded in different cover depth concrete structures.

열순환 횟수에 따른 복합레진의 미세누출

김창윤,신동훈 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.4