• Title/Summary/Keyword: Transport kinetics

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Effect of Sugar Starvation on the Sugar Transport System in Suspension Cultures of Streptanthus trotus (Streptanthus tortus 배양 세포에서 당류고갈이 당류 수송계에 미치는 영향)

  • 조봉희
    • Korean Journal of Plant Tissue Culture
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    • v.27 no.1
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    • pp.47-50
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    • 2000
  • In suspension cultures of Streptanthus. the uptake rate of sugar was increased during the ceil starvation of sugar in the medium. The maximal uptake rate obtained with 3 days of cell starvation. Sugar transport system induced by the sugar starvation was completely inhibited by 10 $\mu$M cycloheximide. Plant cells are known to possess only one sugar transport system, but the uptake rate of glucose obtained a saturated kinetic while the one of sucrose had two different kinetics after the sugar starvation. Induced sugar transport systems had different kinetics compared to plant cell. These results showed that higher plants have adaptable ability to induce new sugar transport systems when the environment changed unsuitable.

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Mercury-Specific Effects on Photosynthetic apparatus of Barley Chloroplasts Compared with Copper and Zinc Ions (구리${\cdot}$아연과 비교한 보리 엽록체의 광합성 기구에 미치는 수은 이온의 특이한 효과)

  • 문병용;전현식
    • Journal of Environmental Science International
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    • v.1 no.1
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    • pp.1.1-11
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    • 1992
  • To find heavy metal-specific effects on the photosynthetic apparatus of higher plants, we investigated effects of $CuCl_2$, HgCl_2$ and $ZnCl_2$ on electron transport activity and chlorophyll fluorescence induction kinetics of chloroplasts isolated from barley seedlings. Effects on some related processes such as germination, growth and photosynthetic pigments of the test plants were also studied. Germination and growth rate were inhibited in a concentration-dependent manner by these metals. Mercury was shown to be the most potent inhibitor of germination, growth and biosynthesis of photosynthetic pigments of barley plants. In the inhibition of electron transport activity, quantum yield of PS II, and chlorophyll fluorescence induction kinetics of chloroplasts isolated from barley seedlings, mercury chloride showed more pronounced effects than other two metals. Contrary to the effects of other two metals, mercury chloride increased variable fluorescence significantly and abolished qE in the fluorescence induction kinetics from broken chloroplasts of barley seedlings. This increase in variable fluorescence is due to the inhibition of the electron transport chain after PS ll and the following dark reactions. The inhibition of qE could be attributed to the interruption of pH formation and do-epoxidation of violaxathin to zeaxanthin in thylakoids by mercury. This unique effect of mercury on chlorophyll fluorescence induction pattern could be used as a good indicator for testing the presence and/or the concentration of mercury in the samples contaminated with heavy metals.

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Impact of mixer design to reactants mixing characteristics and gas-phase reactions in the mixing region of a hydrocarbon reformer (개질기 혼합영역 형상에 따른 반응물의 혼합도 및 가스상 반응특성에 대한 수치해석적 연구)

  • Kim, Sunyoung;Bae, Joongmyeon
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.99.1-99.1
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    • 2011
  • Reactant mixing has a critical role in ensuring reformate quality and an important design objective is to achieve sufficiently complete mixture of reactants. For that purpose it is required to understand the coupled transport-kinetics phenomena in the mixing region. Three-dimensional computational fluid dynamics model was developed and validated in previous works. The mixing characteristics in various alternatives of a prototype mixing chamber were compared, and then a reduced reaction kinetics was applied to two extreme designs for investigating the impact of gas-phase reactions. Both designs did not reach threshold ethylene mole fraction of 0.001, but surprisingly more ethylene was generated in the design having better mixing characteristics. The presentation will deliver the development process of coupled transport and kinetics model briefly and the detailed information about the mixing characteristics and gas-phase reactions in two mixer designs.

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Function through Defects: Thermodynamic and Kinetics of Point Defects in Ionic Solids

  • Ko, Taegyung;Bang, Gyusuk;Shin, Jungmuk
    • The Korean Journal of Ceramics
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    • v.4 no.2
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    • pp.61-67
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    • 1998
  • The significance of point defects as relevant centers concerning electrochemical function is highlighted. Starting from the most simple case of dilute equilibrium bulk defect chemistry, influence of defect interaction and in particular the impact of interfaces on point defect redistribution are considered. Then recent progress in the field of kinetics in bulk and at boundaries is discussed. Finally, selected applications with emphasis on battery and sensor technology are presented.

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Effects of Lewis number on hydrogen diffusion flame structure (수소 확산화염의 구조에 미치는 Lewis 수의 영향)

  • Kim, Hu-Jung;Kim,Yong-Mo;An, Guk-Yeong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.9
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    • pp.1126-1138
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    • 1997
  • An axisymmetric laminar jet diffusion flame has been numerically modelled. The present study employs the refined physical submodels to account for the detailed chemical kinetics and the variable transport properties. It is found that preferential diffusion resulting from variable transport properties significantly influences the hydrogen diffusion flame structure in terms of the spatial distribution for temperature, species concentration, thermal and mass diffusivity, Lewis number, and NO concentration. The preferential diffusion effects on the diffusion flame in the high-pressure environment are also discussed in detail.

A Mathematical Model Development for the Nitrification-Denitrification Coupled Process

  • ;;T. Prabhakar Clement
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.04a
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    • pp.430-433
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    • 2003
  • Nitrogen pollution in urban and rural groundwater is a common problem and poses a major threat to drinking water supplies based on groundwater. In this work, the kinetics of nitrification-denitrification coupled reactions are modeled and new reaction modules for the RT3D code describing the fate and transport of nitrogen species, dissolved oxygen, dissolved organic carbon, and biomass are developed and tested. The proposed nitrogen transformations and transport model showed very good match with the results of other public codes.

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