• Title/Summary/Keyword: Heat-resistant

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Heat-resistant Enamel Varinish (내열성 에나멜 바니쉬)

  • Kim, Yang-Kook;Bae, Hun-Jai
    • Applied Chemistry for Engineering
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    • v.4 no.2
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    • pp.264-272
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    • 1993
  • Current research aimed at investigating of heat-resistance of magnet wire to endow miniaturizing electronic equipment with a high efficiency or reliability. Thermal stability of magnet wire has a close relationship with physical properties of polymeric coating that is formed from enamel varnish. Design of heat-resistant enamel varnish and coating technology of varnish solution were briefly described. Some factors which have a thermal effect on wire were discussed through the evaluation method of the wire properties.

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Suspension Polymerization and Characterization of Transparent Poly(methyl methacrylate-co-isobornyl methacrylate)

  • Park, Sung-Il;Lee, Sang-In;Hong, Soon-Jik;Cho, Kuk-Young
    • Macromolecular Research
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    • v.15 no.5
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    • pp.418-423
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    • 2007
  • A methacrylate copolymer based on isobornyl methacrylate (IBMA) and methyl methacrylate (MMA) was synthesized in an aqueous suspension via free-radical polymerization. The potential of this copolymer as a heat-resistant optical polymer is also discussed. 1,1,3,3-tetramethylbutyl peroxy-2-ethyl hexanoate and n-octyl mercaptan were used as the initiator and chain transfer agents, respectively. The effect of IBMA on the properties of the copolymer was investigated. The composition of the copolymer was analyzed using $^1H-NMR$, and the heat resistance by measuring the glass transition temperature, which exhibited a linear dependency on the IBMA content in the copolymer. Variation of the chain transfer content used in the synthesis step was effective for the optimization of the copolymer for practical use.

Microstructure and Strength Characteristic of 9Cr Ferritic Heat-resistant Steel Applied to the Power Plants (발전플렌트용 9Cr 페라이트 내열강의 미세조직과 강도특성)

  • Kang, C.Y.;Lee, J.M.;Lee, G.H.;Lee, M.Y.;Sung, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.1
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    • pp.27-34
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    • 2000
  • This present study were investigated effect of Ni contents on the microstructure and strength characteristic in 9Cr ferritic heat-resistant steel added 1.7%W in place of Mo in order to restrain laves phase formation. The result obtained from this study are as follow. Volume fraction, number of particles per unite area and particle size of carbide decreased with increase of Ni contents. Other side, carbides of $M_{23}C_6$ type was mainly precipitated in this steel, but laves phases could not precipitated in spite of increasing of aging time. With increase of tempering temperature, hardness was increased, and maximum value was showed around 873k by secondary hardening due to precipitation of $W_2C$ type carbide and then, was decreased. Tensile and yield strength due to decrease precipitation amount of carbide and number of particles per unite area was decreased, but elongation and impact value was increased. In case of aged specimen after tempering than tempered specimen, strength was higher and elongation was lower due to increasing of precipitated amount of carbide and number of particles per unite area.

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Thermal and Optical Properties of Heat-Resistant Core Materials in Plastic Optical Fiber (내열성 플라스틱 광섬유 코어재료의 열적 및 광학적 성질)

  • Lee Gyu-Ho;Cho Won-Keun;Park Min;Lee Hyun-Jung
    • Polymer(Korea)
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    • v.30 no.2
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    • pp.158-161
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    • 2006
  • Recently the application of plastic optical fiber (POF) in automotives and planes demands the heat-resistant and high refractive index con materials. We synthesized polyglutarimides (PGIs) via imidization of PMMA with primary amines under high pressure and high temperature and investigated thermal and optical properties by varying the molar ratio of amines and the type of amines (ethyl amine vs. isopropyl mine). The degree of imidization was calculated based on the peak intensity in $^1H$ NMR and FTIR. We found that the glass transition temperature $(T_g)$ of PGIs increased over $30^{\circ}C$ compared to the traditional core materials in POF, PMMA, and they are stable up to $300\sim400^{\circ}C$. PGIs anthesized with ethyl mine show the better heat resistance than those with isopropyl amines. Additionally, they show the comparable transparency and higher refractive index than PMMA. It implies that they can be utilized as the excellent photo-efficient and heat-resistant core materials in POF.

An Experimental Study on Performance of Heatproof Silicon at the Connector of Boiler Exhaust Tube (배기통과 가스보일러 접속부의 내열실리콘 성능에 관한 실험적 연구)

  • Leem, Sa-Hwan;Lee, Jong-Rark;Kim, Cheol-Jin;Han, Gwi-Ho;Kim, Yong-Joo;Kim, Hee-Soo;Jang, Won-Suk;Lim, Cheong-Hwan
    • Journal of the Korean Institute of Gas
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    • v.11 no.4
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    • pp.91-97
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    • 2007
  • Recently, during the past five years, accidents of gas boiler using city gas have occurred 7.4 times more than those which use LP gas. The number of accidents has increased since the use of city gas boilers has increased. These boiler accidents resulted in 87% death from poisoning of CO, and casualty of the accidents was 4.3 times more than that of other types of accident. Hence this study makes the cause of accidents clear by separation the exhaust tube which is the cause of CO poisoning. Also, this study will establish the safety of heat-resistant silicon through testing the performance of heat-resistant silicon. The experiment showed that common silicon started hardening at $56^{\circ}C$ while the heat-resistant silicon did not begin carbonization until $606^{\circ}C$. Besides at the temperature of $150^{\circ}C$ which is the normal temperature of exhaust tube, common silicon leaked on the pneumatic test after deterioration, but the heat-resistant silicon maintained its original property. With these results, we judge that we can reduce the casualty by CO poisoning if we use the heat-resistant silicon to the connector of he exhaust tube.

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Dry-Heat Treatment Process for Enhancing Viral Safety of an Antihemophilic Factor VIII Concentrate Prepared from Human Plasma

  • Kim, In-Seop;Choi, Yong-Woon;Kang, Yong;Sung, Hark-Mo;Shin, Jeong-Sup
    • Journal of Microbiology and Biotechnology
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    • v.18 no.5
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    • pp.997-1003
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    • 2008
  • Viral safety is a prerequisite for manufacturing clinical antihemophilic factor VIII concentrates from human plasma. With particular regard to the hepatitis A virus (HAV), a terminal dry-heat treatment ($100^{\circ}C$ for 30 min) process, following lyophilization, was developed to improve the virus safety of a solvent/detergent-treated antihemophilic factor VIII concentrate. The loss of factor VIII activity during dry-heat treatment was of about 5%. No substantial changes were observed in the physical and biochemical characteristics of the dry-heat-treated factor VIII compared with those of the factor VIII before dry-heat treatment. The dry-heat-treated factor VIII was stable for up to 24 months at $4^{\circ}C$. The dry-heat treatment after lyophilization was an effective process for inactivating viruses. The HAV, murine encephalomyocarditis virus (EMCV), and human immunodeficiency virus (HIV) were completely inactivated to below detectable levels within 10 min of the dry-heat treatment. Bovine herpes virus (BHV) and bovine viral diarrhea virus (BVDV) were potentially sensitive to the treatment. However porcine parvovirus (PPV) was slightly resistant to the treatment. The log reduction factors achieved during lyophilization and dry-heat treatment were ${\geq}5.55$ for HAV, ${\geq}5.87$ for EMCV, ${\geq}5.15$ for HIV, 6.13 for BHV, 4.46 for BVDV, and 1.90 for PPV. These results indicate that dry-heat treatment improves the virus safety of factor VIII concentrates, without destroying the activity. Moreover, the treatment represents an effective measure for the inactivation of non-lipid-enveloped viruses, in particular HAV, which is resistant to solvent/detergent treatment.

Study on the Conduction Heat Transfer Characteristics According to the Heating Temperature of Lightweight Panel Wall material (경량칸막이 벽체재료의 수열온도에 따른 전도 열전달 특성 연구)

  • Park, Sang-Min;Lee, Ho-Sung;Choi, Su-Gil;Kim, Si-Kuk
    • Fire Science and Engineering
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    • v.32 no.1
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    • pp.46-56
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    • 2018
  • The paper relates to a study on the conduction heat transfer characteristics according to the heating temperature of lightweight panel wall material. Plywoods, marbles, heat resistant glasses, as well as general gypsum board and fire-proof gypsum board, which have been widely used for lightweight panel wall material, were selected as experiment samples, and heating temperatures were set as $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$ and $600^{\circ}C$. Next, each of the heating temperatures were introduced on the bottom part of the wall material for 30 minutes, and analyses were made on the heat transfer characteristics to the backside part on the top part through conduction. As results of the experiment, the maximum backside temperatures were measured up to $190^{\circ}C$ for a general gypsum board, $198^{\circ}C$ for a fire-proof gypsum board, $189^{\circ}C$ for a plywood, $321^{\circ}C$ for a marble, and $418^{\circ}C$ for a heat resistant glass as heating temperatures were introduced maximum of $600^{\circ}C$. In addition, the maximum change rate of conduction heat transfer were measured up to 85 W for a general gypsum board, 95 W for a fire-proof gypsum board, 67 W for a plywood, 1686 W for a marble, and 3196 W for a heat resistant glass as the maximum heating temperatures were introduced up to $600^{\circ}C$. Also, carbonization characteristics of the wallpapers were measured to visually check the danger of conduction heat transfer, and the results showed that smokes were first generated on the attached wallpapers for the heating temperature $600^{\circ}C$, which were 1021 s for a general gypsum board, 978 s for a fire-proof gypsum board, 1395 s for a plywood, 167 s for a marble, and 20 s for a heat resistant glass, and that the first generation of carbonization were 1115 s for a general gypsum board, 1089 s for a fire-proof gypsum board, 1489 s for a plywood, 192 s for a marble, and 36 s for a heat resistant glass.