• 한국신뢰성학회지:신뢰성응용연구
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• 제2권2호
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• pp.63-83
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• 2002

Degradation data can provide more reliability information than traditional failure-time data, especially products with few or no failures. This paper is concerned with a method of estimating lifetime distribution from field data with supplementary information on degradation data and covariates. When a distribution of degradation rate obtained by follow-up study for a portion of products that survive after-warranty follows a reciprocal-Weibull or lognormal distribution. A time-to-failure distribution of the product follows Weibull or lognormal distribution, respectively. A method of estimating lifetime parameters for this kind of data and their asymptotic properties are studied. Effects of after-warranty report probability, follow-up rate, and proportion of degradation data on pseudo maximum likelihood estimators of these parameters are investigated.

• Mass Spectrometry Letters
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• 제3권4호
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• pp.101-103
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• 2012

The ultraviolet (UV) degradation products of photochromic naphthoxazine and naphthopyran derivatives in acetonitrile were separated and identified using liquid chromatography-mass spectrometry (LC-MS). Photodegradation resulted in oxidation of products.

• 농약과학회지
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• 제13권3호
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• pp.127-132
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• 2009

고춧가루를 대상으로 온도별 저장기간 동안의 농약 잔류량의 변화측정을 목적으로 본 실험을 수행하였다. 동시다성분 방법으로 농약 잔류량을 분석한 결과 고춧가루에서 cypermethrin, fenvalerate, kresoxim-methyl, chlorpyrifos, chlorfenapyr, azoxystrobin, tebuconazole등 7종의 농약이 검출되었으며, MRLs(maximum residue limits)을 기준하여 분석한 결과 기준을 초과한 잔류농약은 cypermethrin krexosim-methyl 그리고 tebuconazole 이었다. 가장 많은 감소율을 보인 농약은 azoxystrobin와 fenvalerate로 저장온도에 상관없이 각각 80%이상의 감소율을 보였고, 가장 적은 감소율을 보인 농약은 chlorpyrifos로 실온과 냉장 보관 시 약47%의 감소율을 보였으며 냉동 보관 시에는 약 34%의 감소율을 나타냈다. 60일 경과 후에 저장 온도에 따른 잔류농약 분석 결과 실온에서는 47~84%감소율을 보였고, 냉장에서는 47~85%, 냉동에서는 34~83%의 감소율을 보여, 실온과 냉장 보관 시 크게 차이가 없는 것으로 나타났으며, 실온과 냉장 보관 시보다 냉동보관 시 낮은 농약감소율을 보였다.

• 임산에너지
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• 제24권1호
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• pp.39-46
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• 2005

본 연구에서는 연속형 초임계수 분해장치를 이용하여 처리온도 별로 현사시목재의 당화 가능성과 현사시목재 각 성분의 분해특성을 분석하였다. 미세하게 분쇄한 현사시목분을 물의 초임계압력(23MPa) 조건하에서 각각 아임계온도$(275^{\circ}C,\;325^{\circ}C)$와 초임계온도$(375^{\circ}C,\;415^{\circ}C)$에서 각각 2분간 처리하였다. 갈색을 띤 현사시목분의 액상분해산물에는 어느 정도의 미분해 고형분이 포함되어 있었다. 초임계수 분해온도가 높을수록 현사시목분의 분해율은 증가하여 초임계조건인 $375^{\circ}C$에서는 현사시목분의 $94\%$까지 분해되었다. 각 처리조건에서 생성된 환원당량을 DNS법으로 측정한 결과, 처리온도가 상승함에 따라 생성된 환원당량은 점차 감소하는 경향을 나타내었다. 이는 반응 초기에 생성된 환원당들이 높은 온도의 반응기를 통과하면서 열분해와 유사한 화학적 반응에 의해 더욱 분해되어 퓨란계 화합물로 전환된 것으로 예측되었다. 리그닌의 분해특성을 살펴보기 위하여 액상의 분해산물을 ethylacetate로 추출하여 유기용매 가용부를 GC-MS로 분석하였다. 리그닌의 분해산물은 대부분 페놀성 유도체인 vanillin, guaiacol, syringaldehyde, 4-prophenyl syringol과 dihydrosinapyl alcohol등으로 확인되었으며, 이들의 농도는 처리온도가 상승함에 따라 증가하는 것으로 나타났다. 이러한 리그닌 분해산물은 리그닌고분자의 주요 결합인 에테르 결합이 높은 온도조건하에서 분해에 의한 것으로 예측되었다.

• 한국의류학회지
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• 제33권12호
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• pp.2002-2010
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• 2009

본 연구는 가스크로마토그라피 질량분석기(GC-MS)를 이용하여 황벽의 주 염료성분인 berberine의 퇴화 거동을 조사하는데 목적을 두며 궁극적으로는 심하게 퇴색된 출토직물의 염료성분을 판정하기 위해 각 천연염료별 퇴화물 자료를 수집하고자 한다. Berberine chloride 0.1% 수용액을 $100^{\circ}C$ 오븐법과 $H_2O_2/UV/O_2$법을 이용해 최고 408시간까지 퇴화시키고 GC-MS를 이용해 시료를 분석하였다. 연구결과 오븐 퇴화에 의해 dihydroberberine, 2-pteridinamine, 6,7-dimethyl-N-[(trimethylsilyl)oxy]-, and 8-methoxy-11-[3-methylbutyl]-11H-indolo[3,2-c]-quinoline, 5-oxide의 3개 화합물이 주로 검출되었으며 이들은 berberine 염료의 초기 퇴화 과정에서 나타나는 화합물로 판정되었다. 반면 $H_2O_2/UV/O_2$법으로 퇴화시킨 시료에서는 isobenzofuran-1,3-dione,4,5-dimethoxy-, 9H-fluorene,3,6-bis(2-hydroxyethyl)-, 1,3-dioxolo[4,5-g]isoquinolin-5(6H)-one,7,8-dihydro-, and 3-tert-butyl-4-hydroxyanisole의 4개 화합물이 퇴화 시작과 더불어 새로 생산되었는데 이들은 berberine 염료가 극심한 퇴화 조건에 놓이게 될 때 검출될 수 있는 화합물로 판정되었다. $H_2O_2/UV/O_2$법은 매우 강한 산화작용으로 염료를 퇴화시키는 방법임을 감안할 때 $H_2O_2/UV/O_2$법으로 생성된 화합물은 심하게 퇴색된 출토직물 중 berberine 염료가 사용된 직물을 확인하는데 사용될 수 있을 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권1호
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• pp.53-62
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• 2004

The aim of this study was to predict the energy value and dynamic degradation of roughage in Taiwan using the $Daisy^{(R)}$. in vitro fermentation method to provide information on one of the very important nutrients for ration formulation. The second objective was to study the effects of Aspergillus oryzae (AFE) inclusion on nutrient utilization. Three ruminal fistulated dry dairy cows were used for rumen fluid and fifteen conventional forages used in dairy cattle were collected around this island. The degradability of these feedstuffs with and without AFE ($Amaferm^{(R)}$.) treatment was measured using the $Daisy^{(R)}$. in vitro method. The roughage energy values, including TDN and NEL, were calculated according to Robinson (2000). Results from the 30 h in vitro neutral detergent fiber (NDF) degradability and predicted energy evaluations showed that alfalfa (among the forages) contained the highest degradability and energy values, Bermuda straw having the lowest. Peanut vines and corn silage contained higher energy values and the lowest value found in Pangola and Napier grasses among the locally produced forages. Pangola and Napier grasses had lower values than most imported forages except Bermuda straw. Among the by-products, wheat middling contained the highest NDF degradability, while rice bran contained the richest energy value due to its high oil content. From the dynamic dry matter (DM), organic matter (OM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) degradation, corn silage contained the highest effective degradation among the local forages; wheat middling (among the by-products) degraded the fastest in DM, OM, ADF and NDF and showed the highest effective degradability. AFE inclusion was inconsistent among the forages. Alfalfa hay showed significantly increased 30 h NDF degradability and energy values, Pangola hay, Napier grass and brewer's grains showed decreased degradability and energy values. AFE inclusion increased the DM, OM and NDF degradation rate in most forage, but only increased the DM degradation rate in sorghum distiller's grains, the OM degradation rate in bean curd pomace and the NDF and ADF degradation rates in soy pomace (among the by-products).

• 한국의류학회지
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• 제31권6호
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• pp.859-868
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• 2007

퇴색된 출토복식의 염료를 판정하기 위한 장기적인 프로젝트의 일환으로서 본 연구에서는 울금뿌리로부터 추출한 염료와 추출염료로 염색한 직물을 실험실 조건에서 28일간 퇴화시킨 후 그로부터 생성되는 퇴화 화합물을 가스 크로마토그라피 질량분석법(GC-MS)을 이용해 분석하였다. 2-propenoic acid, 3-(2-hydroxyphenyl)-는 오븐 퇴화시킨 울금추출액 전체에서 지속적으로 검출되었으며, 그 양은 7일 퇴화시료 까지 급격히 감소하다가 그 후 28일까지는 서서히 평형을 유지하였다 울금추출액의 오븐 퇴화 결과 위의 다섯 개 화합물 외에 isovanillin과 vanillic acid가 새롭게 검출되었다. 28일간 퇴화시킨 PER시료에서는 isovanillin과 그 외에 feruloylmethane, 2-propenoic acid, 3-(2-hydroxyphenyl)-, benzoic acid, and vanillic acid가 검출되었다. 울금추출액으로 염색한 직물로부터는 feruloylmethane과 2-propenoic acid, 3-(2-hydroxyphenyl)-가 퇴화물로 검출되었다. PER 방법에서 검출된 isovanillin과 feruloylmethane, 2-propenoic acid, 3-(2-hydroxyphenyl)-, benzoic acid, vanillic acid등은 출토복식 중 울금으로 염색된 직물을 확인하는 데 주요한 대조구 화합물로 사용될 수 있을 것으로 사료된다.

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
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• pp.172.2-172.2
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• 2001

• Food Science and Biotechnology
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• 제18권2호
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• pp.356-361
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• 2009

Lipid oxidation and contents of tocopherols and phospholipids (PL) in soy-added fried products during storage in the dark were studied. Flour dough containing soy flour at 0, 10, 20, and 30% on a weight basis was fried in corn oil at $180^{\circ}C$ for 2.5 min. The fried products were stored at $60^{\circ}C$ for 11 days in the dark. Lipid oxidation of the fried products was evaluated by conjugated dienoic acid (CDA) and p-anisidine values (PAV). Tocopherols and PL were determined by high performance liquid chromatography (HPLC). CDA contents and PAV of the fried products were increased during storage, and addition of soy flour improved lipid oxidative stability of the fried products, which was partly related to increased amount of tocopherols and PL in the soy-added fried products. Tocopherols and PL were degraded during the dark storage of the fried products. Soy flour addition to the dough did not affect the rate of tocopherols degradation during storage of the fried products; however, PL degradation was higher in the soy-added fried products. Residual amounts of $\alpha$-tocopherol and phosphatidylinositol showed high correlations with the lipid oxidation of the fried products during storage in the dark.

• 전기학회논문지
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• 제56권9호
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• pp.1561-1565
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• 2007

According to thermal degradation on power transformers, it is known that electrical, mechanical and chemical characteristics for power transformer's oil-paper are changed. In the chemical property, especially, when the kraft paper is aged, the cellulose polymer chains break down into shorter lengths. It causes decrease in both tensile strength and degree of polymerization of paper insulation. Also the paper breakdown is accompanied by an increase in the content of various furanic compounds within the dielectric liquid. It is known that furanic components in transformer oil come only from the decomposition of insulating paper rather than from the oil itself. Therefore the analysis of furanic degradation products provides a complementary technique to dissolved gas analysis for monitoring transformers when we evaluate the aging of insulating paper by the total concentration of carbon monoxide and carbon dioxide dissolved in oil only. Recently, the analysis of furanic compounds by high performance liquid chromatography(HPLC) using IEC 61198 method for estimating degradation of paper insulation in power transformers has been used more conveniently for assessment of oil-paper. It is know that the main products which is produced by aging are 2-furfuryl alcohol, 2-furaldehyde(furfural), 2-furoic acid, 2-acetylfuran, 5-methyl-2-furaldehyde, and 5-hydroxymethyl-2-furaldehyde. For investigating the accelerated aging process of oil-paper samples we manufactured accelerating aging equipment and we estimated variation of insulations at $140^{\circ}C$ temp. during 500 hours. Typical transformer proportions of copper, silicon steel and iron have been added to oil-paper insulation during the aging process. The oil-paper insulation samples have been measured at intervals of 100 hours. Finally we have analyzed that 2-furoic acid and 2-acetylfuran products of furanic compounds were detected by HPLC, and their concentrations were increased with accelerated aging time.