• 제목/요약/키워드: Oxidation stress

검색결과 391건 처리시간 0.023초

Stress-assisted oxidation behaviour of inconel 52M/316 austenitic stainless-steel dissimilar weld joints in a simulated pressurised water reactor

  • Xu, Youwei;Yang, Binhui;Shi, Yu
    • Nuclear Engineering and Technology
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    • 제54권10호
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    • pp.3778-3787
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    • 2022
  • The stress-assisted oxidation behaviour of Inconel 52 M/316 austenitic stainless-steel (SS) dissimilar weld joints (DMWJ) in a simulated pressurised water reactor environment was investigated. A corrosion galvanic couple formed between the Inconel 52 M and 316 SS due to differences in their nonferrous metal content. The electric field from the corrosion couple attracted metal cations (e.g. Fe2+, Cr3+) to the Inconel 52 M that were deposited as FeCr2O4. An additional corrosion galvanic couple was generated due to variations in the plastic deformation of the DMWJ. The superposition of electric fields from the different couples resulted in ridge-like oxide depositions in the fusion zone.

The Role of Meat Protein in Generation of Oxidative Stress and Pathophysiology of Metabolic Syndromes

  • Ahmad, Muhammad Ijaz;Ijaz, Muhammad Umair;Haq, Ijaz ul;Li, Chunbao
    • 한국축산식품학회지
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    • 제40권1호
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    • pp.1-10
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    • 2020
  • Various processing methods have a great impact on the physiochemical and nutritional properties of meat that are of health concern. Hence, the postmortem processing of meat by different methods is likely to intensify the potential effects on protein oxidation. The influence of meat protein oxidation on the modulation of the systemic redox status and underlying mechanism is well known. However, the effects of processed meat proteins isolated from different sources on gut microbiota, oxidative stress biomarkers, and metabolomic markers associated with metabolic syndromes are of growing interest. The application of advanced methodological approaches based on OMICS, and mass spectrometric technologies has enabled to better understand the molecular basis of the effect of processed meat oxidation on human health and the aging process. Animal studies indicate the involvement of dietary proteins isolated from different sources on health disorders, which emphasizes the impact of processed meat protein on the richness of bacterial taxa such as (Mucispirillum, Oscillibacter), accompanied by increased expression of lipogenic genes. This review explores the most recent evidences on meat processing techniques, meat protein oxidation, underlying mechanisms, and their potential effects on nutritional value, gut microbiota composition and possible implications on human health.

전력케이블내 반도전 재료의 전기적 및 기계적 특성; 체적저항과 Stress-Strain 측정 (Electrical and Mechanical Properties of Semiconductive Shield in Power Cable; Volume Resistivity and Stress-Strain Measurement)

  • 이경용;양종석;최용성;박대희
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제54권2호
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    • pp.45-50
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    • 2005
  • To improve mean-life and reliability of power cable, in this study, we have investigated electrical properties and stress-strain showing by changing the content of carbon black that is semiconductive additives for underground power transmission. Specimens were made of sheet form with the nine of specimens for measurement. Volume resistivity of specimens was measured by volume resistivity meter after 10 minutes in the pre-heated oven of both 25±1 [℃] and 90±1 [℃]. And stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400[Kgf/㎠] and 600[%]. In addition tests of stress-strain were progressed by aging specimens in air oven. From this experimental results, volume resistivity was high according to increasing the content of carbon black. And yield stress was increased, while strain was decreased according to increasing the content of carbon black. And stress-strain were decreased some after aging because of oxidation reaction of chemical defect. We could know EEA was excellent more than other specimens from above experimental results.

지방산 산화 장애 제어를 통한 SREBP-1c 결핍의 소포체 스트레스 유발 비알콜성지방간 보호작용 (SREBP-1c Ablation Protects Against ER Stress-induced Hepatic Steatosis by Preventing Impaired Fatty Acid Oxidation)

  • 이영승;티모씨 에프 오스본;서영교;전태일
    • 생명과학회지
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    • 제31권9호
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    • pp.796-805
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    • 2021
  • 간 소포체(ER) 스트레스는 비알콜성지방간과 인슐린 저항성의 발달에 기여하고, unfolded protein response(UPR)의 구성요소는 지질 대사를 조절한다. 최근 연구에 따르면 ER 스트레스와 비정상적인 세포 지질 대사 사이의 연관성이 보고되었으며, 이 과정에서 지질 대사의 중심 조절자인 sterol regulatory element binding proteins(SREBPs)의 관련성이 확인되었다. 그러나 ER 스트레스 동안 지질 대사를 조절하는 SREBP의 정확한 역할과 비알콜성지방간에 대한 기여는 아직 밝혀지지 않았다. 본 연구에서 SREBP-1c 결핍은 UPR, 염증 및 지방산 산화 조절을 통해 ER 스트레스에 의해 유도된 비알콜성지방간으로부터 생쥐를 보호한다는 것을 보여준다. SREBP-1c는 inositol requiring kinase 1α (IRE1α) 발현을 직접적으로 조절하고 ER 스트레스에 의해 유도된 tumor necrosis factor-α의 활성화를 매개하여 peroxisome proliferator-activated receptor γ coactivator 1-α (PGC1α)의 감소와 그에 따른 지방산 산화의 장애를 유발한다. 그러나, SREBP-1c의 유전적 결핍은 이러한 현상을 보호하여 간 염증과 지방 축적을 완화시킨다. SREBP-1c 결핍이 ER 스트레스에 의해 유도된 염증 신호를 방지하는 메커니즘은 아직 밝혀지지 않았지만, SREBP-1c가 결핍된 Kupffer 세포에서 IRE1α 신호의 변화가 염증 신호에 관여할 수 있을 것으로 생각된다. 본 연구결과는 SREBP-1c가 ER 스트레스에 의해 유도된 비알콜성지방간에서 UPR 및 염증의 조절에 중요한 역할을 함을 시사한다.

Scale 파괴거동 측정 및 해석 (Analysis and Measurement on Failure Behavior off Scales by Acoustic Emission Method)

  • 최진원
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 추계학술대회 논문집
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    • pp.330-331
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    • 2005
  • It was found possible to evaluate the temperature at which major scale failure takes place during cooling by installing a most modem acoustic emission(AE) analytical system. Ultra low carbon steel and low carbon steels containing a few minor alloying elements were oxidized in air at 900, 1050 and $1200^{\circ}C$ for 20 min, and then cooled in vacuum at 30, 70 and $110^{\circ}C/min$. The significance of the present research is the evaluation of the spallation temperature and thus the calculation of apparent thermal stress for scale spallation using the difference between oxidation temperature and spallation temperature. They were assessed as 0.22 to 0.68, 0.45 to 1.80, and 0.65 to 1.95 GPa for oxidation at 900, 1050 and $1200^{\circ}C$, respectively.

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다공질 실리콘 (Porous Silicon) 의 열산화 (Thermal Oxidation of Porous Silicon)

  • 양천순;박정용;이종현
    • 대한전자공학회논문지
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    • 제27권10호
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    • pp.106-112
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    • 1990
  • 다공질 실리콘을 열산화할 때 산화의 온도 의존성과 IR흡수 스펙트럼을 조사하여 다공질 실리콘외 산화특성을 조사하였다. PSL(porous silicon layer)을 $700^{\circ}C$에서 1시간, $1100^{\circ}C$에서 1시간으로 2단계 습식산화시켜 bulk 실리콘의 열산화막과 같은 성질의 수십 ${\mu}m$두께의 OPSL(oxidized porous silicon layer)을 짧은 시간에 형성시킬 수 있으며, 식각율과 항복전계는 산화온도와 산화 분위기에 크게 의존하는 것으로 나타났다. 이때 PSL의 산화율은 약 390nm/s이고, 항복전계는 1.0MV/cm~2.0MV/cm의 분포를 갖는다. 웨이퍼 휨을 측정하여 고온 열산화시 발생하는 산화막의 stress를 조사하였다. $1000^{\circ}C$ 이상의 고온에서 건식산화할 경우 발생하는 stress는 ${10^2}dyne/{cm^2}~{10^10}dyne/{cm^2}$로 측정되었다.

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The Analysis of Three-dimensional Oxidation Process with Elasto-viscoplastic Model

  • Lee Jun-Ha;Lee Hoong-Joo
    • Transactions on Electrical and Electronic Materials
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    • 제5권6호
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    • pp.215-218
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    • 2004
  • This paper presents a three-dimensional numerical simulation for thermal oxidation process. A new elasto-viscoplastic model for robust numerical oxidation simulation is proposed. The three-dimensional effects of oxidation process such as mask lifting effect and corner effects are analyzed. In nano-scale process, the oxidant diffusion is punched through to the other side of the mask. The mask is lifted so the thickness of oxide region is greatly enhanced. The compressive pressure during the oxidation is largest in the mask corner of the island structure. This is because the masked area near the corner is surrounded by an area larger than the others in the island structure. This stress induces the retardation of the oxide growth, especially at the masked corner in the island structure.

Alloy 600의 결정립계 산화에 대한 표면 변형의 영향 (Effects of Surface Deformation on Intergranular Oxidation of Alloy 600)

  • 하동욱;임연수;김동진
    • Corrosion Science and Technology
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    • 제19권3호
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    • pp.138-145
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    • 2020
  • Immersion tests of Alloy 600 were conducted in simulated primary water environments of a pressurized water reactor at 325 ℃ for 10, 100, and 1000 h to obtain insight into effects of surface deformation on internal and intergranular (IG) oxidation behavior through precise characterization using various microscopic equipment. Oxidized samples after immersion tests were covered with polyhedral and filamentous oxides. It was found that oxides were abundant in mechanically ground (MG) samples the most. The number density of surface oxides increased with time irrespective of the method of surface finish. IG oxidation occurred in mechanically polished (MP) and chemically polished (CP) samples with thin internal oxidation layers. However, IG oxidation was suppressed with relatively thick internal oxidation layers in MG samples compared to MP and CP samples, suggesting that MG treatment could increase resistance to primary water stress corrosion cracking (PWSCC) from the standpoint of IG oxidation. As a result, appropriate surface treatment for Alloy 600 could prevent oxygen diffusion into grain boundaries, inhibit IG oxidation, and finally induce its high PWSCC resistance.

동규자(冬葵子)와 경마자의 항산화(抗酸化) 효능(效能) 연구(硏究) (Effects of Malvae Semen and Abutili Semen on Anti-oxidation Activities)

  • 최정운;성락술;이영종
    • 대한본초학회지
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    • 제21권4호
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    • pp.159-170
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    • 2006
  • Objectives : Anti-oxidation activities of Malvae Semen and Abutili Semen were compared and evaluated. Methods : We tested the anti-oxidant effect through in vitro experiment and in vivo experiment that induced oxidative stress using ethanol. Results : 1. In the anti-oxidative activities of Malvae Semen and Abutili Semen they had high effects in case of the scavenging activitie of DPPH and superoxide anion radical, and inhibitory effect of linoleic acid oxidation. 2. Malvae Semen had large quantities of phenolic compound than Abutili Semen, but the anti-oxidative activity of Malvae Semen was weaker than that of Abutili Semen. 3. The anti-oxidative effect of Abutili Semen was more strong than that of Malvae Semen in the rat stressed by ethanol. Conclusion : Anti-oxidation activities of Abutili Semen were stronger than those of Malvae Semen. Therefore, the complementary usage of Malvae Semen and Abutili Semen can be considered.

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SEPOX (selective poly oxidation) process에서 Si-buffer layer에 발생하는 pinhole 현상에 대한 연구 (Si-buffer pinholes in the SEPOX (selective poly oxidation) process)

  • 윤영섭
    • 전자공학회논문지A
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    • 제33A권6호
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    • pp.151-157
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    • 1996
  • We propose a mechanism for the formation of pinholes in the Si-buffer layer, through the observations with varying the process- and structure variables in the SEPOX (selective poly-oxidation) process, an isolation method for sub-u DRAMs. Pinholes are formed through the accumulation of Si vacancies generated by the oxidation of Si, in which Si atoms leave the sites (vacancies) at the Si/SiO$_{2}$ interfaces and diffuse into the oxide to be oxidized near interface. In the course of the accumulation of Si-vacancies, the stress induced in the Si-buffer layer affects the migration of vacancies to result in the final size and distribution of pinholes. This paper may be, to our knowledge, the first report about the oxidation-induced pinhole in the Si/SiO$_{2}$ system.

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