• 제목/요약/키워드: Degradation factor

검색결과 972건 처리시간 0.028초

철도차량 견인전동기의 상태진단 및 상시감시 기술 (Condition Diagnosis & On-line Monitoring Technology on the Traction Motor for Railway Rolling Stock)

  • 왕종배;변윤섭;백종현
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 제2회 학술대회 논문집 일렉트렛트 및 응용기술전문연구회
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    • pp.36-39
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    • 2000
  • This paper presents the technology of condition diagnosis & life estimation on insulation system of the traction motor. In the non-destructive methods for diagnosis of coil insulation state, residual dielectric strength is estimated by the D-map which consist of the partial discharge quantity Q and average degradation degree $\Delta$. In the operating history of machine, the N-Y life estimation method is based on the stop-starting numbers and operating times with considering each degradation factor by the thermal, electrical and heat-cycle stress. With the on-line conditioning monitoring on the currents of traction motors, detecting the abnormal operating state due to bearing faults, stator or armature faults, eccentricity related faults and broken rotor bars can be performed.

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토양 중 mineral에 의한 염소계 유기화합물 분해 특성 연구

  • 최정윤;심상규;이우진
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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    • pp.33-36
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    • 2006
  • The reductive dechlorination of chlorinated organic compounds by soil minerals in soil and groundwater were carried out in this study. FeS, green rust, and magnetite were chosen as the representative soil minerals which were capable of degrading chlorinated compound in soil system. FeS was the most effective reductant in degradation of carbon tetrachloride. The reductive degradation of CT and 1,1,1-TCA by FeS was much faster than that of 1,2-DCB and 2,4-DCP. The reactivity of FeS was effectively improved by the addition of trace metals. The addition of Co to FeS suspension enhanced the reaction rate of 1,2-DCB by a factor of 46 compared to that by FeS without Co.

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Degradation of immunoglobulins, protease inhibitors and interleukin-1 by a secretory proteinase of Acanthamoeba cutellanii

  • Na, Byong-Kuk;Cho, Jung-Hwa;Song, Chul-Yong;Kim, Tong-So
    • Parasites, Hosts and Diseases
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    • 제40권2호
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    • pp.93-99
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    • 2002
  • The effect of a secretory proteinase from the pathogenic amoebae Acanthamoeba castellanii on host's defense-oriented or regulatory proteins such as immunoglobulins, interleukin-1, and protease inhibitors was investigated. The enzyme was found to degrade secretory immunoglobulin A (slgA), IgG, and IgM. It also degraded $interleukin-1{\alpha}$ ($IL-l{\alpha}$) and $IL-l{\beta}$. Its activity was not inhibited by endogenous protease inhibitors, such as ${\alpha}$2-macroglobulin, ${\alpha}l-trypsin$ inhibitor, and ${\alpha}2-antiplasmin$. Furthermore, the enzyme rapidly degraded those endogenous protease inhibitors as well. The degradation of host's defense-oriented or regulatory proteins by the Acanthanoeba proteinase suggested that the enzyme might be an important virulence factor in the pathogenesis of Acanthamoeba infection.

Degradation of Collagens, Immunoglobulins, and Other Serum Proteins by Protease of Salmonella schottmulleri and its Toxicity to Cultured Cells

  • Na, Byoung-Kuk;Kim, Moon-Bo;Song, Chul-Yong
    • Journal of Microbiology
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    • 제34권1호
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    • pp.95-100
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    • 1996
  • The effect of the extracellular protease of Salmonella schottmulleri on human serum constituents such as immunoglobulins, hemoglobin and lysozyme and tissue constituents such as fibronectin and collagens was investigated. This protease degraded collagens (type I and III), fibronectin and serum proteins such as human hemoglobin and lysozyme. Bovine serum albumin was degraded slightly. Thus, the present study suggested the possibility that this protease is not only played an important role in invasion of S. schottmulleri by degrading the constituent proteins such as collagens and fibronectin but also induced complications observed in septicemia and chronic infections by degrading the serum proteins. This protease is also capable of degrading defence-oriented humoral proteins, immunoglobulins (IgG and IgM). Furthermore, it is toxic to HEp-2 cells. These findings clarified the possible role of Salmonella protease as a virulence factor in the pathogenesis of Salmonella infections.

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증기발생기 전열관 마모 파열 거동 (Burst Behavior of Wear Scar of Steam Generators Tubes)

  • 김홍덕
    • 한국압력기기공학회 논문집
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    • 제6권2호
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    • pp.1-8
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    • 2010
  • Nuclear steam generator tubes have experienced wear degradation at tube support structure. Morphology of wear scar was analyzed by using eddy current signal. A burst test facility for steam generator tubes was established and tubes with 3 types of defects were tested. The burst test results show that the depth of wear scar is the main factor influencing the burst pressure of tubes, meanwhile, both the longitudinal length and the angle also have effect on the burst pressure. Based on test results, the burst pressure equation for wear degradation was proposed.

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장기간 사용한 Cr-Mo강의 피로강도향상 방법에 관한 연구 (A Study of Fatigue Strength Improvement for Cr-Mo Steel in Long Term service)

  • 진영준
    • 한국안전학회지
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    • 제16권2호
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    • pp.27-35
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    • 2001
  • For the purpose of healing the degradation part, $CO_2$ laser beam was irradiated with different irradiation condition (porer, diameter, velocity and beam type) to find out optimum irradiation condition. The test series of hardness, residual stress measurement, and fatigue were carried out after the irradiation. Experimental results show that micro-hardness values on the surface of the irradiated specimens m approximately 2.5 times higher than those of un-irradiated ones. Fatigue tests show that the fatigue life was improved by the compressive residual stress after laser beam irradiation. However, some specimens with different conditions show the shorter fatigue life. It means that laser beam irradiation with optimum irradiation condition and optimum absorb energy, Q can improve the fatigue strength.

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Conservation of Biodiversity and Forest Resources in Nepal -Degradation and Threats-

  • Ghimire, Bimal Kumar;Islam, Mohammad Saiful;Chun, Su-Kyoung
    • 한국가구학회지
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    • 제19권4호
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    • pp.300-306
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    • 2008
  • Nepal is rich country in terms of its vast array of biological diversity. The relationship between local communities and the biological diversity in Nepal is a very entangle one, whereby two-thirds of our population are heavily dependent upon the biodiversity for their survival. The destruction of biodiversity signifies the destruction of people's livelihoods and survival. Biodiversity and genetic resources conservation has been a most significant part of the Nepalese society due to its socio-economic and cultural importance and provides the human race trees for timber, fuel, food, industrial raw materials, pharmaceuticals, beverages and environmental stabilization. Threats to biodiversity at global level is of greater concern, specially, human activities are the greatest factor currently affecting biodiversity, through the use of natural resources by industry, agriculture, hunting, and energy generation.

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ZPCCL계 바리스터의 충격전류 스트레스에 대한 노화 특성 (Degradation Characteristics Against Impulse Current Stress of ZPCCL-Based Varistors)

  • 박종아;유대훈;남춘우;서형권
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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    • pp.315-317
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    • 2005
  • The microstructure, electrical, and degradation characteristics against impulse current of ZPCCL-based varistors were investigated with various sintering temperature in the range of $1240\sim1300^{\circ}C$. The densification of varistors was improved, but the nonlinearity was deteriorated with increase of sintering temperature. The varistors sintered at $1250^{\circ}C$ and $1260^{\circ}C$ exhibited high stability against surge stress. On the whole, the variation of characteristics of varistor for surge stress was increased in order of varistor voltage$\rightarrow$nonlinear exponent$\rightarrow$dissipation factor$\rightarrow$leakage current.

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Improved Understanding of LeTID of Single-crystalline Silicon Solar Cell with PERC

  • Kim, Kwanghun;Baik, Sungsun;Park, Jaechang;Nam, Wooseok;Jung, Jae Hak
    • Current Photovoltaic Research
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    • 제6권4호
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    • pp.94-101
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    • 2018
  • Light elevated temperature induced degradation (LeTID) was noted as an issue in multi-crystalline silicon solar cells (MSSC) by Ram speck in 2012. In contrast to light induced degradation (LID), which has been researched in silicon solar cells for a long time, research about both LeTID and the mechanism of LeTID has been limited. In addition, research about LeTID in single-crystalline silicon solar cells (SSSC) is even more limited. In order to improve understanding of LeTID in SSSC with a passivated emitter rear contact (PERC) structure, we fabricated four group samples with boron and oxygen factors and evaluated the solar cell characteristics, such as the cell efficiency, $V_{oc}$, $I_{sc}$, fill factor (FF), LID, and LeTID. The trends of LID of the four group samples were similar to the trend of LeTID as a function of boron and oxygen.

Evaluation of effective cross-area of reinforced concrete wall considering chloride diffusion using ANN

  • Hyeon-Keun Yang;Jun-Hee Park
    • Nuclear Engineering and Technology
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    • 제56권10호
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    • pp.4254-4262
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    • 2024
  • Reinforced concrete structures are subject to exposure to chloride ions in the air, leading to chloride penetration, and carbonation attacks resulting from exposure to carbon dioxide. This chemical degradation process induces corrosion of reinforcing bars within concrete, significantly impacting durability. Structures situated in coastal areas, such as nuclear power plants, are particularly susceptible to rapid chloride penetration due to the high chloride concentration in the air. This study utilizes existing experimental data to forecast the chloride diffusion coefficient employing artificial neural network (ANN technology). The total number of experimental data was 535 gathered from 18 papers. Through analysis of the chloride coefficient and predicted degradation depth, the effective cross-sectional area of concrete is examined, and the deterioration of wall performance is forecasted.