• 제목/요약/키워드: Oxygen resistance

검색결과 738건 처리시간 0.025초

부식전위 기준에 의한 철근콘크리트 구조물의 부식진단의 위험성에 관한 고찰 (Consideration on the Risk of Corrosion Assessment in Reinforced Concrete Structure by Corrosion Potential Criterion)

  • 정진아
    • Corrosion Science and Technology
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    • 제14권3호
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    • pp.147-152
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    • 2015
  • Corrosion of steel reinforcement is a major factor in the deterioration of harbour and bridge structure. Steel corrosion in concrete must be checked for assessing the condition of a reinforced concrete structure. There are several ways how to measure the corrosion condition of reinforced concrete, but the corrosion potential measurement is a very simple, rapid, cost-effective and non-destructive technique to evaluate the severity of corrosion in reinforced concrete structure, therefore commonly used by engineers. However some particular situations may not relate to the reinforcement corrosion probability and a simple comparison of the corrosion potential data with the ASTM C876 Standard on steel reinforcement corrosion probability could be meaningless and not give reliable informations because of environment factors as oxygen concentration, chloride content, concrete resistance. Therefore this paper explains the risk of corrosion assessment in reinforced concrete structure and how many factors can affect the reliability of the corrosion potential data.

초정밀 온도센서의 저온 영역 교정 장치 개발 (Development of the calibration system for very accurate thermometers at low temperatures)

  • 양인석;송창호;강기훈;김용규
    • 센서학회지
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    • 제17권3호
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    • pp.188-194
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    • 2008
  • For the accurate calibrations of thermometers at low temperatures, triple points of oxygen and argon have been realized using sealed-type triple point cells. The triple points were realized with both adiabatic and continuous heating methods. The resistance of three capsule-type standard platinum resistance thermometers were measured at the triple points of oxygen, argon, mercury and water for the calibrations of these thermometers in the range from $-220^{\circ}C$ to $0.01^{\circ}C$. The extended uncertainty, with the coverage factor of 2, of the calibration in this range is smaller than 1 mK.

초경합금상에 합성된 다이아몬드 박막의 부착력 특성 (Adhesion Characteristics of Diamond Thin Film on WC-Co Substrate)

  • 이상희;박상현;이덕출
    • 한국전기전자재료학회논문지
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    • 제14권7호
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    • pp.584-589
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    • 2001
  • Diamond thin films were synthesized on WC-Co substrate by RF PACVD(radio frequency plasma-assisted chemical vapor deposition) technique with H$_2$-CH$_4$-O$_2$ gas mixture. WC-Co substrate was pre-treated in HNO$_3$solution, scratched with 3$\mu\textrm{m}$ diamond paste and exposed in the O$_2$ plasma before deposition. The diamond thin film prepared at 11% oxygen concentration showed the best quality of good adhesion and wear resistance at various oxygen concentration with the fixed 5% CH$_4$ concentration.

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열처리에 따른 SOI 기판에서의 전기전도특성의 이상 거동 (Abnormal behaviors in electrical conductions of SOI substrate by thermal annealing temperature)

  • 조원주
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.126-127
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    • 2008
  • The effects annealing conditions on the electrical conductions of SOI substrate were studied. The reversible change of resistance and carrier concentration in accordance with the annealing temperature were observed for the first time in SOI substrate. The thermal donors due to interstitial oxygen atoms contribute the change of resistance and carrier concentration. Final1y, we show that the furnace annelaing at $500^{\circ}C$ at final heat treatment stage is effective for eliminate the thermal donor effects in SOI substrate.

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A Co-expression Network of Drought Stress-related Genes in Chinese Cabbage

  • Lee, Gi-Ho;Park, Young-Doo
    • 원예과학기술지
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    • 제35권2호
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    • pp.243-251
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    • 2017
  • Plants have evolved to adapt to abiotic stresses, such as salt, cold, and drought stress. In this study, we conducted an in-depth analysis of drought resistance mechanisms by constructing a gene co-expression network in Chinese cabbage (Brassica rapa ssp. pekinensis L.). This drought stress co-expression network has 1,560 nodes, 4,731 edges, and 79 connected components. Based on genes that showed significant co-expression in the network, drought tolerance was associated with the induction of reactive oxygen species removal by raffinose family oligosaccharides and inositol metabolism. This network could be a useful tool for predicting the functions of genes involved in drought stress resistance in Chinese cabbage.

규칙화된 Fe-Al 계 금속간 화합물의 산화특성과 미끄럼 마모거동과의 관계에 대한 연구 (A Study on the Relationship between Oxidation and Sliding Wear Behavior of Ordered Fe-Al Intermetallic Alloys)

  • 김용석
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 춘계학술대회논문집
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    • pp.144-148
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    • 1999
  • The relationship between oxidation and sliding wear behavior of Fe-28 at%. Al alloys with B2 ordered structure has been investigated. Sliding wear tests of the alloys have been carried out under various environmental conditions using a pin-on-disk wear tester. The wear rate of the ordered alloys in an oxygen atmoshpere was found to be much lower than in an oxygen atmosphere showed that Fe2O oxides formed on the wearing surface. The oxide layer prevented direct contact of the two mating materials and therefore improved wear resistance of the Fe-Al intermetallic alloy. It was found that the surface Al2O3 oxide layer which provides good oxidation resistance and improved mechanical properties broke down easily and didnot function properly as an oxidation barrier.

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Laser Ablation에 의하여 $LaAlO_3$(100) 기판 위에 증착된 Y-Ba-Cu-O 박막에 대한 연구 (Study of Laser Ablated Y-Ba-Cu-O Thin Films on $LaAlO_3$(100)Substrates)

  • 조윌렴;이규철;고도경;이헌주;노태원;김정구;허필화
    • 한국세라믹학회지
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    • 제28권12호
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    • pp.1005-1011
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    • 1991
  • Y-Ba-Cu-O thin films were in-situ fabricated on LaAlO3(100) substrates using the second harmonics of a pulsed Nd:YAG laser. Thin films were deposited under 200 (mtorr) of oxygen atmosphere, when the substrate temperature was changed between 67$0^{\circ}C$ and 82$0^{\circ}C$. After deposition, the films were in-situ annealed at 50$0^{\circ}C$ under 2/3 bar of oxygen pressure. We showed that the deposition temperature affects the formation of superconducting phase, the resistance, and the surface morphology. The Y-Ba-Cu-O thin films deposited at 76$0^{\circ}C$ show the zero resistance critical temperature of 85 K.

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플렉서블 CIGS 태양전지의 고온고습 환경 고장 기구 분석 (Evaluation of Failure Mechanism of Flexible CIGS Solar Cell Exposed to High Temperature and Humid Atmosphere)

  • 김혁수;변재원
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제16권1호
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    • pp.41-47
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    • 2016
  • Purpose: The purpose of this study was to evaluate electrical and structural degradation of flexible CIGS sollar cell exposed to high temperature and humid atmosphere. Method: Accelerated degradation was performed for various time under $85^{\circ}C/85%RH$ and then electrical and structural properties were analyzed by 4-point probe method, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results: Sheet resistance of the top ITO layer increased with exposure time to the high temperature and humid atmosphere. Blunting of the protrusion morphology of ITO layer was observed for the degraded specimen, while no phase change was detected by XRD. Oxygen was detected at the edge area after 300 hours of exposure. Conclusion: Increase in electrical resistance of the degraded CIGS solar cell under high temperature and humid environment was attribute to the oxygen or water absorption.

Fire Resistance Properties of Chloroprene Rubber containing Inorganic Flame Retardant

  • Sung, Il Kyung;Park, Chan Young
    • Elastomers and Composites
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    • 제50권4호
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    • pp.279-285
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    • 2015
  • This study examined the mechanical properties and the flame retardant properties of CR rubber containing inorganic flame retardant with various contents of aluminium trihydroxide (ATH, $Al(OH)_3$). The content of aluminium trihydroxide was added in 0, 30, 50, 70 and 100 phr for T1~T5 samples. It was found that increasing the amount of addition over 30 phr resulted in decreasing the mechanical properties. On the other hand in oxygen index measurements T1 sample showed a value of 38.6%, indicating the improvement of flame retardant properties showed a value of 49.7~64.2%. In case of burn test, it was confirmed that CR rubber containing over ATH 50phr content showed performance corresponding to that of first grade fire-resistance.

Co1-xMgxO세라믹스의 MgO함량에 따른 전기적 성질 및 산소가스 감지특성 (Effect of MgO Contents on Electrical Properties and Oxygen Sensing Characteristics in Co1-xMgxO Ceramics)

  • 최현국;이덕동;조상희
    • 한국세라믹학회지
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    • 제26권1호
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    • pp.7-12
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    • 1989
  • The effects of composition ratios and sintering conditions in Co1-xMgxO ceramics on the sintering characteristics, electrical properties and oxygen sensing characteristics were investigated. In the same sintering conditions, porosity decreased with increase of MgO contents. The relationshiop of temperature and resistance in Co1-xMgxO ceramics showed NTC(negative temperature coefficient) characteristics at the temperature range from $700^{\circ}C$ to 1,10$0^{\circ}C$. In the case of pure CoO, however, the PTC(positive temperature coefficient) characteristics were shown over about 90$0^{\circ}C$. The electrical conductivity of Co1-xMgxO ceramics decreased proportionally with decrease of oxygen partial pressure at the range from 1 to 10-4(atm). Particularly, Co0.5Mg0.5O ceramics showed the highest sensitivity to oxygen gas.

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