• 제목/요약/키워드: C35

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가압 졸-겔 코팅법에 의한 세라믹막의 기체투과 특성 (Gas Permaeation Characteristics of Ceramic Membranes by the Pressurized Sol-Gel Coating Techique)

  • 현상훈;강범석
    • 한국막학회:학술대회논문집
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    • 한국막학회 1993년도 춘계 총회 및 학술발표회
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    • pp.35-35
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    • 1993
  • 튜브형 $\alpha-Al_2O_3$ 담체에 졸-겔 침지코팅법과 가압코팅(pressurized coating) 법으로 boehmite 졸과 극미세 입자 SiO$_2$ 및 TiO$_2$ 졸을 코팅한 후 200$\circ$C~500$\circ$C 에서 열처리하여 복합분리막을 제조하였다.

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W35Fe43C22 비정질 합금분말의 결정화 거동 (Crystallization behavior of W35Fe43C22 amorphous alloy powders)

  • 권영준;유정선;박수근;이근효;조기섭
    • 열처리공학회지
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    • 제31권4호
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    • pp.165-170
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    • 2018
  • W, Fe, and carbon powders were mechanical alloyed to produce $W_{35}Fe_{43}C_{22}$ ternary alloy powders containing nanocrystal W embedded within amorphous matrix. When the powder samples were heated to the primary crystallization temperature of $735^{\circ}C$, most parts of their amorphous region were fully crystallized to [W,Fe]-rich $M_6C$ carbides. Interestingly, a little portion of the carbides changes to stoichiometric line compounds ($M_{12}C$ and $W_6Fe_7$) and a solution phase (Fe-rich bcc), and remaining parts of the crystallites were amorphized again. The resulting microstructure was retained even by cyclic heating between room temperature of $1,200^{\circ}C$, and thus we found that the amorphous structure can be irreversibly formed at above glass transition temperature.

Effects of Storage Duration and Temperature on the Chemical Composition, Microorganism Density, and In vitro Rumen Fermentation of Wet Brewers Grains

  • Wang, B.;Luo, Y.;Myung, K.H.;Liu, J.X.
    • Asian-Australasian Journal of Animal Sciences
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    • 제27권6호
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    • pp.832-840
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    • 2014
  • This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures ($5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$) and four durations (0, 1, 2, and 3 d) were arranged in a $4{\times}4$ factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as $25^{\circ}C$ and $35^{\circ}C$. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds $35^{\circ}C$, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above $35^{\circ}C$ during summer.