• 제목/요약/키워드: ennoblement

검색결과 4건 처리시간 0.019초

Crevice Corrosion Resistance of Stainless Steels in Natural Sea Water with different Post Welding Treatment

  • Lee, Y.H.;Kim, Y.H.;Kim, H.
    • Corrosion Science and Technology
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    • 제2권5호
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    • pp.219-224
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    • 2003
  • Crevice corrosion of stainless steels in natural seawater was investigated for several post weld treatments; as-annealed, as-welded, pickled, and ground. The results confirmed the effect of the biofilm on the cathodic reaction leading to an ennoblement of the rest potential. The degree of ennoblement of corrosion potential depends on the surface finish. As-annealed and pickled samples show stable corrosion potential approaching to 200 ~ 300 mV (SCE) while as-welded and ground samples show the fluctuating corrosion potential. This points to a situation where there are conflicting effects determining the trend in free corrosion potential. Crevice corrosion initiation will tend to pull the free corrosion potential in the active direction, whereas the presence of biofilm will tend to ennoble corrosion potential. There was no visible attack on UNS S31803, S32550, and 2205W. Therefore, those stainless steel grades appeared to be resistant to crevice corrosion in natural seawater on condition of weld metal.

ANALYSIS ON MICROBIOLOGICALLY INFLUENCED CORROSION FAILURE CASE OF SUS316L STAINLESS STEEL WELDS

  • Miyano, Yasuyuki;Yamamoto, Michiyoshi;Watanabe, Kazuya;Kikuchi, Yasushi
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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    • pp.133-138
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    • 2002
  • Microbiologically Influenced Corrosion (MIC) was suspected in a corrosion failure of cooling system of stainless piping welded joint, carrying marine water. Marine water which is used for cooling water in a plant was transferred to the laboratory and used for experiment. In the first experiment, weld metal samples were exposed to the test solution for 56 days (marine water and sterilized marine water (control)). Surface condition of experimental coupons was observed using a Scanning Electron Microscope (SEM). In another experiment, free corrosion potential of these material was monitored for 56 days. Pitting corrosion was found in the coupons exposed to marine water. Free corrosion potential ennoblement was found to be significant compared to control. It was suspected that this corrosion case was MIC. In the second experiment, coupons were exposed to diluted nutrient medium containing single culture of microbes isolated from the MIC causing marine water sample used for the first experiment. After exposure test, surface condition of experimental coupon was observed using SEM. Pitting corrosion was found in coupons exposed to some of the isolates. The results indicate that they contribute to the corrosive effect of the SUS316L welds.

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조선시대 자연환경보전에 관한 연구 (A Study on Conservation of the Natural Environment in Chosun-Dynasty, Korea)

  • 오승봉;안동만
    • 한국조경학회지
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    • 제23권1호
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    • pp.51-65
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    • 1995
  • Conservation of the natural environiment In chosun-Dynasty, Korea, is analysed on the basis of the of official records of the king's offices(Chosun-wangjo-sillok). In the popular ideologies of the dynasty, Seongleehak(philosophy of humanity arid natural laws) and Pungsu (geomancy) , the naturnal enviroment is defined as an entity con-sisting of Cheon (heaven) , San(mnountains) , Su (water), Geumsu (animals)and Chomok (plants) .the notion of Tacksi-Tackmul(being careful to take natural resources at the right time) was one of the Cheonmyung (eavenly decrees) . It was believed that violation of this principle resulted in natural disasters. Sasan(four mountains surrounding Hansungbu-, the capital city, now Seoul) , were strictly preserved according to geomancy practices. In areas other than the capital city, Sanlimcheontack (mountains, forests, rivers and ponds) were con-served for sustained production of building materials especially pinetrees for ship building, foods, firewoods, horses, and orter useful natural resources. Various conservation policy insturuments were adopted. Prunning trees was permitted only in October. Capturing fishes was allowed only after the spawning period. Protection areas were designated in Sasan, Seongjoesiplee (surroundings of the capital city) , Geumsan(protected mountains), Kangmujang(hunting and army training grounds), Sijang(firewood areas), Mokmajang(horse ranches) and Neungyuk(royal tombs) . Activities prohibited for conservation purposes included cutting timbers, burning, building houses or tombs, dumping wastes, farming and breaking up fresh land, grazing, hunting and trespassing. Positive actions for conservation were rituals to Heaven ennoblement of natural elements such as mountians or rivers, planting trees, Boto (supplementing soil on low ridges) , Josan (mounding) and making ponds. Boto, Josan and making ponds were to make ideal terrains for geomancy. Many government bodies and civil servants were engaged in the conservation activities. For example, Sanjik(forest keeper) was a special position with responsibility for forest management.

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시판 덖음녹차의 품질에 따른 이화학적 특성 (Chemical Properties on the Quality of Marketed Roasting Green teas)

  • 신미경;장미경;서은숙
    • 한국식품조리과학회지
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    • 제11권4호
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    • pp.356-361
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    • 1995
  • 시판되고 있는 녹차를 가격과 적채시기에 따라 상품, 중품 및 하품으로 구분하여 수분, 회분, 총 질소, 탄닌, 카페인, 색도 및 엽록소의 함량을 분석하고 관능평가를 실시하여 품질에 따른 상관관계를 조사한 결과는 다음과 같다. 1. 수분의 함량은 2.17-3.67%, 회분은 4.50-5.17%, 총 질소는 4.38-4.68%로 품질에 따른 차이가 없었다. 2. 탄닌은 상품이 11.09%,중품이 14.22%, 하품이 14.44%로서 상품이 중품과 하품보다 유의적으로 낮았다. 3. 질소와 탄닌의 조성비율(N/T)은 상품이 39.5%, 중품이 32.6%, 하품이 32.70%으로 상품일수록 유의적으로 높게 나타났다. 4. 카페인은 상품이 평균 1.78%, 중품이 1.32%, 하품이 0.92%로 적채시기가 늦어질수록 유의적으로 감소하였다. 5. 엽록소 a와 b의 량은 상품이 중품과 하품보다 유의적으로 높게 나타나 총엽록소 함량은 상품이 297.37 mg%, 중품이 182.89 mg%, 하품이 204.79 mg%으로 상품이 가장 높았다. 6. 색도에서 Yellow치는 상품과 중품이 하품보다 유의적으로 높았으나, red와 blue치에서는 품질간의 차이가 없었다. 7. 관능 평가는 상품이 중품과 하품보다 외판, 맛이 좋았으며 향기와 색깔은 상품과 중품이 비슷하게 나타나 전체적인 관능평가도는 상품, 중품, 하품순으로 유의적으로 높게 나타났다. 8. 가격과 적채시기에 따른 품질은 카페인, 외관, 맛과는 양의 상관관계(P < 0.01)를, tannin과는 음의 상관관계(P < 0.05)를 보였다. 또한 질소와 탄닌의 조성비율(N/T)은 탄닌과는 높은 음의 상관관계(P < 0.01)를 나타내었으나 카페인과는 양의 상관관계(P < 0.05)를 나타내었다. 이상에서 적채시기가 빠른 상품일수록 질소와 탄닌의 조성비율(N/T)이 높고, 카페인 및 총 엽록소의 함량이 높았으며, 관능평가에서도 좋게 나타났다.연화도는 증가하였으나, 기호도의 경우는 알갱이 15%,분말 10%를 장조림에 첨가하였을 때 가장 높은 것으로 나타났다.반후의 색차도 PT20이 가장 낮았다.ference. The pH and titratible acidity of the two juices with different ratios were in the range of 4.92~4.98 and 36.g∼37.4 ml, respectively.2K 이었으며, 다층 YbB $a_2$C $u_3$A $g_{x}$(x=5, 16 and 53)의 $T_{on}$ 은 88~90K이었다._{on}$ 은 88~90K이었다.er-designity. These trends identify the overall prevailing conditions of Korean landscape architectural design over the past thirty years.ang(목마장 horse ranches) and Neungyuk(능역 royal tombs) . Activities prohibited for conservation purposes included cutting timbers, burning, building houses or tombs, dumping wastes, farming and breaking up fresh land, grazing, hunting and trespassing. Positive actions for conservation were rituals to Heaven ennoblement of natural elements such as mountians or rivers, planting trees, Boto (보토 supplementing soil on low ridges) , Josan (조산 mounding)

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