• 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.

• Journal of the Korean Wood Science and Technology
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• 제44권5호
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• pp.685-694
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• 2016

본 연구에서는 반탄화 과정에서 바이오매스 열분해 거동을 열중량 분석과 발생되는 기체분석으로 확인하였다. 반응온도는 $220{\sim}300^{\circ}C$, 승온속도 $10{\sim}30^{\circ}C/min$, 반응시간은 110분으로 고정하여 분석하였다. 백합나무 중량감소율은 $220^{\circ}C$에서 8.01~8.81%, $300^{\circ}C$에서 71.86~77.38%로 나타났으며, $240^{\circ}C$ 이상에서 급격하게 증가하였다. 반면 낙엽송 중량감소율은 $300^{\circ}C$에서 49.58~54.15%로 백합나무와 비교하여 낮았다. 백합나무에 대한 활성화 에너지는 87.32~91.24 kJ/mol으로 승온속도에 따라 큰 차이를 나타내지 않았으며, 낙엽송에 대한 활성화 에너지는 83.85~91.60 kJ/mol으로 나타났다. 반탄화 과정에서 발생하는 가스성분은 대부분 헤미셀룰로오스 유래 성분이었으며 반응온도가 증가하면서 성분의 종류 및 농도도 증가하였다. 백합나무에서는 furfural, acetic acid가 고농도로 검출되었다.

• 공업화학
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• 제19권2호
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• pp.191-198
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• 2008

혼합폐플라스틱의 열분해로부터 얻어진 고분자성분의 열적분해 특성에 대한 연구를 TGA와 GC-MS를 이용하여 수행하였다. 열적분해의 속도론적 연구는 $10{\sim}50^{\circ}C/min$ 사이의 여러 가열속도에서 비등온 질량감소 기술을 이용하여 수행하였으며 활성화 에너지 및 반응차수 등과 같은 속도 상수들에 대한 정보를 얻기 위하여 문헌에 제시된 여러 가지의 속도론 해석 방법을 이용하여 질량감소 곡선 및 그 미분 값을 해석하였다. 또한 회분식 열분해 반응기를 이용하여 반응온도 및 반응시간에 따른 액상 생성물의 수율변화를 고찰하였으며 GC-MS를 이용하여 반응온도의 증가에 따른 액상 생성물의 특성연구를 수행하였다.

• 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.

• Applied Biological Chemistry
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• 제29권3호
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• pp.260-265
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• 1986

잎담배의 중요(重要)한 색소성분(色素成分)인 ${\beta}-carotene$을 $400^{\circ}C,\;600^{\circ}C$ 및 $800^{\circ}C$에서 각각 열분해(熱分解)한 다음 생성(生成)된 휘발성(揮發性) 성분(成分)들을 GC 및 GC/MS에 의해 확인하고 분해온도(分解溫度)에 따른 생성물(生成物)의 차이점을 비교하였다. 각 온도별(溫度別) 분해생성물(分解生成物)로부터 36종(種)의 방향족(芳香族) 탄화수소(炭化水素) 10종(種)의 ${\beta}-ionone$ 관련화합물을 포함하여 53종(種)의 휘발성(揮發性) 화합물(化合物)을 확인하였고 이들 중에서 ${\beta}-cyclogeraniol$을 포함한 37종(種)의 화합물(化合物)은 ${\beta}-carotene$의 열분해생성물(熱分解生成物)로서 아직까지 보고되지 않은 성분(成分)들이다. 한편 $400^{\circ}C$와 $600^{\circ}C$에서 열분해(熱分解)했을 때의 중요(重要) 생성물(生成物)은 $p-xylene,\;{\alpha}-terpinene,\;{\beta}-cyclocitral,\;ionene(1,2,3,4-tetrahydro-1,1,6-trimethylnaphthalene),\;{\beta}-ionone$ 및 dihydroactinidiolide 등이었고, $800^{\circ}C$에서는 위에서의 6종(種)의 성분(成分) 이외에도 toluene이 많이 생성(生成)되었다.

• 한국응용과학기술학회지
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• 제24권4호
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• pp.416-426
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• 2007

Polypropylene (PP) composites with wood flour/wax/coupling agent were manufactured by melt compounding and injection molding. The influence of wood flour(WF), wax, and coupling agent on the mechanical and thermal properties of the composites was investigated. The addition of wood flour to neat PP has the higher tensile modulus and strength compared with neat PP. The presence of wax also improved the tensile modulus. At the same loading of PP and WF, the addition of coupling agent highly decreased the tensile modulus, and increased the tensile strength. From thermogravimetric analysis (TGA), the addition of wax improved the thermal stability of the composites in the later stages of degradation. The presence of MAPP and wood flour in turn decreased thermal stabilities of composites. From differential scanning calorimetry analysis (DSC), neither the loading of wax. nor the presence of MAPP has shown significant effect on the thermal transition of composites.

• Journal of the Korean Wood Science and Technology
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• 제34권5호
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• pp.59-66
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• 2006

The thermal properties of wood flour, Hwangto, and maleated polyethylene (MAPE) reinforced HDPE composites were investigated in this study. The thermal behavior of reinforced wood polymer composites was characterized by means of thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. Hwangto and MAPE were used as an inorganic filler and a coupling agent, respectively. According to TGA analysis, the increase of wood flour level increased the thermal degradation of composites in the early stage, but decreased in the late stage. On the other hand, Hwangto reinforced composites showed the higher thermal stability than virgin HDPE, from the determination of differential peak temperature ($DT_p$). Decomposition temperature of wood flour and/or Hwangto reinforced composites increased with increase of heating rate. From DSC analysis, melting temperature of reinforced composites little bit increased with the addition of wood flour or Hwangto. As the loading of wood flour or Hwangto to HDPE increased, overall enthalpy decreased. It showed that wood flour and Hwangto absorbed more heat energy for melting the reinforced composites. Hwangto reinforced composites required more heat energy than wood flour reinforced composites and virgin HDPE. Coupling agent gave no significant effect on the thermal properties of composites. Thermal analyses indicate that composites with Hwangto are more thermally stable than those without Hwangto.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3808-3814
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• 2023

The thermal stability of nitric acid solutions after contact with non-irradiated and irradiated tributyl phosphate (TBP) and its solution in Isopar-M has been studied. It has been established that exothermic processes occur during heating due to the interaction of soluble radiolysis products and the decomposition of the extractant with nitric acid. Such processes can occur at temperatures below 100 ℃, but unlike a thermal explosion that occurs in seconds, they are longer in time and are accompanied by weak heat evolution. Their intensity depends on the composition of the extractant, the concentration of HNO₃, and the volume ratio of the organic and aqueous phases. The presence of extractant degradation products in raffinates does not pose a risk of a rapid evolution of gaseous products during evaporation, however, the presence of reducing agents can significantly increase the intensity of the exothermic decomposition of raffinates.

• Applied Biological Chemistry
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• 제40권6호
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• pp.519-524
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• 1997

우렁쉥이 껍질로부터 추출한 카로테노이드 색소의 식품첨가물로서의 이용 가능성을 알아보기 위하여 SDE(simultaneous distillation and extraction/concentration) 장치를 이용하여 휘발성 화합물을 추출하였다. 이를 GC 및 GC-MS로 분석하여 총 63성분의 휘발성 화합물을 동정하였고, 대부분의 화합물이 카로테노이드의 가열분해로 생성되어지는 것으로 나타났다. 동정된 화합물중 대표적인 화합물은 1,3,5-trimethylbenzene, 3,5,5-trimethyl-3-cyclohexen-1-ol, 3,5,5-trimethyl-3-cyclohexen-1-one, 1,1,2,3-tetramethyl-2-cyclohexen-5-ol, 1,1,2,3-tetramethyl-2-cyclohexen-5-one, 2,3,4,4-tetramethyl-6-hydroxy-2-cyclohexene-1-one, 1,2,3,8-tetrahydro-3,3,6-trimethyl-1-naphtol, dihydroacetinidolide, ${\beta}-ionone$, 2-(1,1,5-trimethyl-3-hydroxy-5-cyclohexen-6-yl)-1-to-lylethene, 2,6-dimethyl-8-(1,1,5-trimethyl-3-hydroxy-5-cyclohexen-6-yl)-1,3,5-octatriene-7-yne 등 이었다. 이중 몇가지 화합물의 생성기작도 추정해 보았다.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2000년도 추계 연합심포지엄.학술발표회 논문발표집
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• pp.161-161
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• 2000