• 제목/요약/키워드: Crosslinked

검색결과 578건 처리시간 0.038초

가교폴리에틸렌 수지의 가교온도변화에 따른 전기트리의 진전과정에 관한 연구 (A Study on Growthing Process of Electrical Tree According to Crosslinked Temperature Variation in XLPE)

  • 김상기;김덕근;임장섭;오무송;김태성
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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    • pp.173-176
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    • 1999
  • Crosslinked Decree is an important 7actor to determine dielectric property of crosslinked polyethylene(XLPE) used for the insulation material in Power cables. Recently, though it is necessary to investigate electrical properties according to crosslinked degree as a Part of the whose characterization of cable. it is not examined closely. In this study. crosslinked degree of samples were measured according to temperature and holding time of crosslinking. electrical tree characteristics of these characteristics of these samples were analyzed by crosslinked degree and applied temperature that was chanced from normal temperature to operating temperature of power cables. As a result. when the crosslinked degree was low, dielectric properties were decreased and influence of temperature was increased. but the crosslinked degrees were high, initiation voltages of treeing were increased and dielectric properties were improved. It is proved that the optimum crosslinked degree was one of most important factor for aging time and residual lifetime of Power cable.

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Crosslinked IIR의 블렌드비에 따른 EPDM의 내기체투과특성 향상 (Gas Impermeability Enhancement of EFDM/Crosslinked IIR Blends)

  • 김현준;정일현;홍인권;박재우
    • Elastomers and Composites
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    • 제33권3호
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    • pp.193-200
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    • 1998
  • 고무소재는 다양한 종류별로 구조에 따라 다른 물성을 갖는 것으로 알려져 있다. 일반적으로 EPDM 고무는 내후성과 내오존성이 뛰어나고 열이나 냉기, 습기의 노출에도 잘 견디는 것으로 밝혀진 바 있다. 한편 crosslinked IIR은 물과 기체투과에 대한 저항성이 큰 것으로 알려져 두가지 성분의 장점을 갖도록 EPDM/crosslinked IIR의 블렌드를 새로운 형태의 소재로 추천할 수 있다. 따라서 본 실험에서는 EPDM과 crosslinked IIR의 블렌드비를 변화시키면서 가교시간과 블렌드후 물리/화학적 특성의 개선을 목표로 하였다. 결과적으로 30wt.%의 crosslinked IIR 조성을 갖는 블렌드소재가 내후성, 내오존성 및 내기체투과 특성이 뛰어나, O-링이나 전기관련 제품에 상업적으로 응용가능한 것으로 판단되었다.

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Cholesterol Removal from Lard with Crosslinked ${\beta}$-Cyclodextrin

  • Kim, S.H.;Kim, H.Y.;Kwak, H.S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제20권9호
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    • pp.1468-1472
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    • 2007
  • The present study was carried out to determine the optimum conditions of different factors (ratio of lard to water, ${\beta}$-CD concentrations, mixing temperature, mixing time and mixing speed) on cholesterol reduction from lard by using crosslinked ${\beta}$-CD. Crosslinked ${\beta}$-CD was prepared with adipic acid. When the lard was treated under different conditions, the range of cholesterol removal was 91.2 to 93.0% with 5% crosslinked ${\beta}$-CD, which was not significantly different among treatments. In a recycling study, cholesterol removal with crosslinked ${\beta}$-CD in the first trial was 92.1%, which was similar to that with new crosslinked ${\beta}$-CD. In up to eight time trials, over 90% of cholesterol removal was found. The present study indicated that the optimum conditions for cholesterol removal using crosslinked ${\beta}$-CD were a 1:3 ratio of lard to water, 5% crosslinked ${\beta}$-CD concentration, $40^{\circ}C$ mixing temperature, 1 h mixing time and 150 rpm mixing speed. In addition, crosslinked ${\beta}$-CD made by adipic acid resulted in an effective recycling efficiency.

XLPE의 가교도 분포에 따른 전기트리 진전 특성 분석 (Analysis on Electrical Tree Growth Characteristics in XLPE According to Crosslinked Degree)

  • 김상기;김덕근;이정빈;이진;김태성
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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    • pp.901-903
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    • 1998
  • Crosslinked Degree is an important factor to determine dielectric property of crosslinked polyethylene(XLPE) used for the insulation material in power cables. Recently, though it is necessary to investigate electrical properties according to crosslinked degree as a part of the whole characterization of cable. it is not examined closely. In this study, crosslinked degree of samples were measured according to temperature and holding time of crosslinking, electrical tree characteristics of these samples were analyzed by crosslinked degree and applied temperature that was changed from normal temperature to operating temperature of power cables. As a result. when the crosslinked degree was low, dielectric properties were decreased and influence of temperature was increased. but the crosslinked degrees were high. initiation voltages of treeing were increased and dielectric properties were improved. It is proved that the optimum. crosslinked degree was one of most important factor for aging time and residual lifetime of power cable.

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Proton Conducting Membrane Based on Crosslinked Sulfonated Polyimide for Direct Methanol Fuel Cell

  • Sung, Kyung-A;Kim, Wan-Keun;Oh, Keun-Hwan;Choo, Min-Ju;Park, Jung-Ki
    • 전기화학회지
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    • 제12권3호
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    • pp.245-250
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    • 2009
  • Crosslinked membrane based on sulfonated polyimide was prepared by the introduction of crosslinkable monomer in polymerization process and crosslinking during membrane casting. Crosslinked membranes showed different properties from non-crosslinked membranes. Crosslinking decreased methanol crossover and therefore unit cell using crosslinked membrane showed increased open circuit voltage, 0.81 V, in comparison with unit cell using noncrosslinked membrane, 0.71 V. In addition, water uptake of crosslinked membrane, 40.5%, was lower than that of non-crosslinked membrane, 57.0%, and this resulted in improved dimensional stability. However, proton conductivity of crosslinked membranes showed rather low relative to non-crosslinked membrane due to reduced water uptake.

카본블랙 충전 HDPE/EEA Copolymer 복합재료에 있어서 가교구조가 PTC 특성에 미치는 영향 (Effect of Crosslinking on the PTC Stability Carbon Black Filled HDPE/EEA Copolymer Composite)

  • 이건주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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    • pp.140-145
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    • 2001
  • In order to apply for silane crosslinking process to PTC products, especially. self-regulating heater, silane crosslinked samples were compared with radiation crosslinked sample in terms of PTC characteristic and PTC stability. Silane crosslinked samples have lower PTC intensity than radiation crosslinked sample. It can be explained that multiple networks of silane crosslink restrict the movement of molecules in the composite as the sample is heating. As a result of heat cycles at $140^{\circ}C$, the changes of volume resistivity and PTC intensity for radiation crosslinked sample were higher than those of silane crosslinked samples. Whereas, in the case of heat cycles at $85^{\circ}C$, which is limiting temperature for self-regulating heater, both silane and radiation crosslinked samples show stable results without pronounce changes of resistivity up to five cycles.

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Optimization of Cholesterol Removal by Crosslinked ${\beta}$-Cyclodextrin in Egg Yolk

  • Jung, Tae-Hee;Park, Heung-Sik;Kwak, Hae-Soo
    • Food Science and Biotechnology
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    • 제14권6호
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    • pp.793-797
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    • 2005
  • Optimum conditions for cholesterol removal in egg yolk were evaluated based on ratio of egg yolk-to-water, crosslinked ${\beta}$-cyclodextrin (${\beta}$-CD) concentration, and mixing temperature, time, and speed by adding crosslinked ${\beta}$-CD treated with adipic acid. Cholesterol removal in egg yolk-water mixture increased with increasing ${\beta}$-CD level (10-25%). About 95% was removed by 25% ${\beta}$-CD at 1:1 ratio of egg yolk-to-water and 800 rpm mixing at $40^{\circ}C$ for 30 min. In recycling study, removal rates were measured using ten times recycled crosslinked ${\beta}$-CD in egg yolk, and 85% cholesterol removal was observed with eight times reuse. These results indicated that over 90% cholesterol was removed at 1:1 ratio of egg yolk-to-water, 20% crosslinked ${\beta}$-CD addition, and 30 min mixing with 600 rpm at $40^{\circ}C$.

Thermally Crosslinked Polyimide Binders for Si-alloy Anodes in Li-ion Batteries

  • Chang, Hyeong-Seok;Ji, Sang-Gu;Rho, Miso;Lee, Byoung-Min;Kim, Sung-Soo;Choi, Jae-Hak
    • Journal of Electrochemical Science and Technology
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    • 제13권3호
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    • pp.339-346
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    • 2022
  • Silicon (Si) has attracted considerable attention due to its high theoretical capacity compared to conventional graphite anode materials. However, Si-based anode materials suffer from rapid capacity loss due to mechanical failure caused by large volume change during cycling. To alleviate this phenomenon, crosslinked polymeric binders with strong interactions are highly desirable to ensure the electrode integrity. In this study, thermally crosslinked polyimide binders were used for Si-alloy anodes in Li-ion batteries. The crosslinked polyimide binder was found to have high adhesion strength, resulting in enhanced electrode integrity during cycling. Therefore, the Si-alloy anodes with crosslinked polyimide binder provide enhanced electrochemical performance, such as Coulombic efficiency, capacity retention, and cycle stability.

Cholesterol Removal from Homogenized Milk with Crosslinked β-cyclodextrin by Adipic Acid

  • Han, Eun-Mi;Kim, Song-Hee;Ahn, Joungjwa;Kwak, Hae-Soo
    • Asian-Australasian Journal of Animal Sciences
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    • 제18권12호
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    • pp.1794-1799
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    • 2005
  • The present study was carried out to develop crosslinking of $\beta$-cyclodextrin ($\beta$-CD) using adipic acid, and to determine the optimum conditions of different factors ($\beta$-CD concentration, mixing temperature, mixing time and mixing speed) on cholesterol reduction from homogenized milk. Crosslinked $\beta$-CD was prepared with adipic acid. When the milk was treated with different conditions, the cholesterol removal rate was in the range of 92.1 to 93.1% with 1% $\beta$-CD addition, which were not significantly different among treatments. After cholesterol removal from milk, the used crosslinked $\beta$-CD was washed for cholesterol dissociation and reused. For recycling study, the cholesterol removal rate in the first trial was 92.5%, which was mostly same as that using new crosslinked $\beta$-CD. With repeated ten time trials using same sample, 81.4% of cholesterol was removed from milk. Therefore, the present study indicated that the optimum conditions for cholesterol removal using crosslinked $\beta$-CD were 1% $\beta$-CD addition and 10 min mixing with 400 rpm speed at 5$^{\circ}C$ with over 90% cholesterol removal. In addition, crosslinked $\beta$-CD made by adipic acid resulted in the effective recycling efficiency.

Morphological Change of Crosslinked ${\beta}$-Cyclodextrin after Recycling

  • Han, Eun-Mi;Kim, Song-Hee;Kim, Ki-Woo;Kwak, Hae-Soo
    • Journal of Dairy Science and Biotechnology
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    • 제25권1호
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    • pp.9-13
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    • 2007
  • The present study was carried out to examine the effect of crosslinked ${\beta}$-cyclodextrin(${\beta}$-CD) made by adipic acid on cholesterol removal rate and find the structural change after recycling on SEM observation. The size reduction and morphological changes were found during the recycling process and the profound changes were observed at 8th time reuse. After cholesterol removal in milk, the used crosslinked ${\beta}$-CD was washed for cholesterol dissociation and reused. In recycling study, the cholesterol removal rate at first trial was 92.5% in milk, which was mostly same as that using new crosslinked ${\beta}$-CD(92.4%). With repeated 10th reuse of crosslinked ${\beta}$-CD resulted in 81.4% of cholesterol removal in milk. Similar trend was found in cream and cholesterol removal was 91.5% at 1st trial and 83.4% at 10th trial. In both milk and cream samples, the removal rate at 1st reuse was not significantly different from that at 6th reuse(p>0.05). The present study indicated that crosslinked ${\beta}$-CD made by adipic acid resulted in the effective recycling efficiency, especially up to 6th reuse and morphological modifications were not distinguishable up to 8th reuse.

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