• Title/Summary/Keyword: Kcal

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A Kinetic Study on the Hydration Process of Barley Kernels with Various Polishing Yields (도정수율별 보리의 수화공정(水和工程)에 관(關)한 속도론적(速度論的) 연구(硏究))

  • Mok, Chul-Kyoon;Lee, Hyun-Yu;Nam, Young-Jung;Min, Byong-Yong
    • Korean Journal of Food Science and Technology
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    • v.15 no.2
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    • pp.136-140
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    • 1983
  • The hydration characteristics of barley kernels with various polishing yields were investigated at temperatures of $20-60^{\circ}C$ and their sorption kinetics were studied. The moisture gain in initial stage of hydration was directly proportional to square root of hydration time and there was a break point at the moisture gain of 0.45-0.55g $H_2O/g$ solid. The hydration rate was great in order of polishing yield of 50, 70, 95, 90 and 100%, and increased with increasing hydration temperature. The diffusivity of water into barley kernels followed Arrhenius equation, and the activation energies in hydration reaction of polished barley were ranged from 6.9 to 9.5 Kcal/mole and that of non-polished one was 11.6Kcal/mole.

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The Oxidation Behavior of Pitch based Carbon Fibers in ${CO}_2$ Gas and Air (${CO}_2$ gas및 공기중에서 피치계 탄소섬유의 산화거동)

  • No, Jae-Seung;Seo, Dong-Su
    • Korean Journal of Materials Research
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    • v.7 no.2
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    • pp.121-128
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    • 1997
  • Two-types of carbon fiber, anisotropic- and isotropic- pitch based, were expose to isothermal oxidation in air and $CO_{2}$ gas and the weight change rates was measured by TGA apparatus. Thc oxidation rate was laster in air than in $CO_{2}$ gas, and the oxidation rare of isotropic T- 101s liher was over 23 9 times faster than that of anisotropic HM-60 filler at $600^{\circ}C$ in air. The activation energy was 36-56 Kcal/mole at lower temperature range and 6- 13 Kcal/molc at higher temperature range. It was higher that the transition temperalure 01 reaction zone(zone 1. 2, :i) of 11M-GO fiber than that of T-101s fiber, and it was higher in $CO_{2}$ gas than in air. From SEM observation, it Lvas found that the oxidation of carbon fibers was progressed through the imperfection.

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Kinetics for Reduction of trans-[Co(en)$_2$(NO$_2$)Cl]$^+$ and [Fe(H$_2$O)$_6$]$^{2+}$ in Acidic Solution (산성용액내에서 trans-[Co(en)$_2$(NO$_2$)Cl]$^+$ 와 [Fe(H$_2$O)$_6$]$^{2+}$ 와의 산화환원반응에 대한 속도론적 연구)

  • Park Byung-Kak;Woo Tae-Ha;Lim Joo-Sang;Song Yeung-Dae
    • Journal of the Korean Chemical Society
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    • v.34 no.5
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    • pp.460-464
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    • 1990
  • Proton behavior was investgated for the redox reaction of trans-[$Co(en)_2(NO_2)Cl]^+$ with aqueous Fe(II) in acidic solution by UV/vis-spectrophotometric method. The reaction order of proton is first one and the rate constant(k$_H^+$) is 6.7 ${\times}\;10^{-1}L^2/mol^2{\cdot}min$. The values of $E_a$, ${\{Delta}H^{\neq}$, ${\{Delta}S^{\neq}$ are 14.5 Kcal/mol, 13.8 Kcal/mol and -18.3e.u., respectively. As the result of analysis of kinetic data, it has been found that this reaction proceeds through inner-sphere mechanism.

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