• 한국추진공학회지
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• 제19권5호
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• pp.84-90
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• 2015

티타늄 합금은 고온 추진체의 부품에 사용될 경우, 고온의 화염에서 순간적으로 노출될 수 있음으로, 고온의 화염하에서의 내산화특성을 평가할 필요가 있다. 본 연구에서는 Ti64 합금 (Ti-6%Al-4%V) 및 코팅된 Ti64 합금을 고온화염하에서 산화손상 및 내산화 특성을 평가하고자 하였다. Ti64 합금의 코팅은 알루미늄 확산코팅법을 사용하여 코팅을 수행하였다. 표면에 알루미나이드층이 코팅되지 않은 Ti64 합금은 고온의 화염 노출시에 표면 박리현상이 발생하였으나, 코팅된 시험편은 표면박리현상이 나타나지 않았고 알루미나이드 층의 산화물 생성으로 인하여 표면이 보호됨을 관찰할 수 있었다. 화염노출시 코팅층의 역할을 고찰하기 위하여 코팅층을 분석하였으며, 조직의 변화를 고찰하고 논의하였다.

• 농약과학회지
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• 제4권3호
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• pp.1-6
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• 2000

광조건 및 토양중에서 제초제 dicamba의 분해특성을 조사하기 위하여 자연광 조건과 물리화학성이 다른 2종류의 토양을 선택하여 수행하였다. 광조건하에서 dicamba의 분해율은 처리 9주후에 3.3%였으며, 주분해산물로써 4-hydroxy dicamba가 검출되었고, 또한 기존에 알려진 분해산물인 5-hydroxy dicamba도 확인되었다. 한편 Dicamba는 살균되지 않은 토양에서 배양 8주후에 $14.7{\sim}23.2%$가 분해되었으며, 토양중 dicamba 분해경로는 주로 탈메칠 (demethylation) 작용에 의해 이루어졌다. 또한 살균된 토양에서 dicamba 분해는 아주 서서히 되는 것으로 보아 dicamba 분해에는 미생물이 주로 작용하는 것으로 나타났다.

• 열처리공학회지
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• 제14권2호
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• pp.110-117
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• 2001

Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. It was found that the carbides became coarser and spheroidized as aging time increased. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the ultrasonic attenuation and velocity measurements. Ultrasonic velocity was found essentially insensitive to the microstructural changes resulting from aging heat treatment. However, the ultrasonic attenuation was observed to increase with increasing aging time. Also, it was noticed that the change of ultrasonic attenuation with aging time was more sensitive at high frequency regions.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권4호
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• pp.227-230
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• 2000

Bunker-A oil-degrading microorganisms were isolated from a marine environment using an enrichment culture technique. The isolated strain EL-081K was identified as the genus Acinetobacter based on the results of morphological, culture, and biochemical tests. The optimal temperature and initial pH for bunker-A oil degradation were $25^{\circ}C$ and 7.0, respectively, including aeration. The optimal medium composition for the degradation of bunker-A oil by Acinetobacter sp. EL_O81K was 10 ml/l bunker-A oil as the carbon source and 0.1% (NH$_4$)$_2$SO$_4$as the nitrogen source. Under the above conditions, the biodegradability of bunker-A oil was 38% after 96 hours of incubation. The addition of detergent did not increase the bunker-A oil degradation.

• 보존과학회지
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• 제2권2호
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• pp.15-24
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• 1993

To understand the morphological change of ancient woods, samples classified by cell type, burial environment and species were collected and observed using microscopy. Decay of wood by cell type could classified into two types. First, degraded secondary wall was formed granular residues in $S_2$ layer and was remained $S_3$ layer and compound middle lamella. Second, the cell wall was slightly degraded and cracked in secondary wall. A gradual thinning of cell wall was occured. The compound middle lamella was separated from secondary wall. The resistance of degradation is increased at vessels, parenchyma, and tracheid and wood fiber in the order named. The type of degradation by species could be classified into four types. Overall degradation type; the degradation of cell wall is usually heavy and the extent of degradation Varies by part of the same sample. Partial degradation type ; this type shows severely different decay type by part of the sample. Nondegraded cells were mixed with degraded cells on the same sample. Erose degradation type ; thinning of the cell wall was occoured and the degradation type was different by part. Slight degradation types ; secondary wall was slightly degraded, cracked and separated from compound middle lamella. Considering different type of burial environment, dry wood was similiar to sound wood and slightly decayed. Waterlogged and peat burial wood was heavilydecayed. Between species of under the same environment, decay type and extent were diferentiated from each other.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 반도체재료
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• pp.75-78
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• 2001

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 임시총회 및 추계 학술발표회
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• pp.17.2-17
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• 1999

• Journal of Pharmaceutical Investigation
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• 제2권2호
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• pp.5-17
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• 1972

It was reported that cyclodextrin has a distinctive ability to form inclusion compound with a wide variety of compounds. The authors studied the stability of acetylsalicylic acid in cyclodextrin solution. From the results of this experiment, the decomposition of Aspirin in cyclodextrin solution was progressed according to the pseudofirt order reaction and its degradation rate constant was decreased and the thermodynamic activation energy of the degradation of aspirin was accetrated with the increase of cyclodextrin Conclusively, it was considered that cyclodextrin increased the stability of aspirin in aqueous solution by its inclusion compound formation.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.749-752
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• 2014

Spacer 유무와 핀 폭, 채널길이에 따른 n채널 MuGFET의 단채널 및 열화 특성을 비교 분석 하였다. 사용된 소자는 핀 수가 10인 Tri-Gate이며 Spacer 유무에 따른 핀 폭이 55nm, 70nm인 4종류이다. 측정한 소자 특성은 DIBL, subthreshold swing, 문턱전압 변화 (이하 단채널 현상)과 소자열화이다. 측정 결과, 단채널 현상은 spacer가 있는 것이 감소하였고, hot carrier degradation은 spacer가 있고 핀 폭이 작은 것이 소자열화가 적었다. 따라서, spacer가 있는 LDD(Lightly Doped Drain) 구조이며 핀 폭이 작은 설계방식이 단채널 현상 및 열화특성에 더욱 바람직하다.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4252-4265
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• 2023

In the case of nuclear power plants near end of their design life, a reassessment of the performance of safetyrelated equipment may be necessary to determine whether to shut down or extend the operation of the power plant. Therefore, it is necessary to evaluate the level of performance decline due to degradation. Electrical cabinets, including MCC and switchgear, are representative safety-related equipment. Several studies have assessed the degradation and seismic performance of nuclear power plant equipment. Most of those researches are limited to individual components due to the size of safety-related equipment and test equipment. However, only a few studies assessed the degradation performance of electrical cabinets. The equipment of various nuclear power plants is anchored to concrete foundations, and crack in concrete foundations is one of the most representative of degradation that could be visually confirmed. However, it is difficult to find a study for analysis through testing the effect of cracks in concrete foundations on the response of electrical cabinet internal equipment fixed by anchors. In this study, using a simple cabinet model considering cast-in-place anchor in uncracked and cracked concretes, a tri-axial shaking table tests were performed and the seismic behavior were observed.