• 제목/요약/키워드: Chemical Kinetics

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마일드 연소장 수치계산을 위한 화학반응기구의 예측성능 검토 (Investigation on the Prediction Performance of the Chemical Kinetics for the Numerical Simulation of MILD Combustion)

  • 김유정;오창보
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.341-344
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    • 2012
  • The prediction performance of the chemical kinetics for the numerical simulation of MILD combustion was investigated. A wall-confined turbulent methane jet combustor was adopted as a configuration. Four chemical kinetics, such as a global 3-step, WD4, Skeletal, and DRM-19, were investigated, The air stream of the wall-confined MILD jet combustor was diluted with combustion products. It was found that the DRM-19 was optimal for the numerical simulation of the MILD combustion.

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Accumulation and Decay of Macroscopic Correlations in Elementary Reactions Kinetics

  • Doktorov, Alexander B.;Kipriyanov, Alexander A.;Kipriyanov, Alexey A.
    • Bulletin of the Korean Chemical Society
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    • 제33권3호
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    • pp.941-952
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    • 2012
  • In the present contribution the Encounter Theory (ET) (the prototype of the classical Collision Theory in rarefied gases) concepts for widely occurring diffusion assisted irreversible bulk reactions A + A ${\rightarrow}$ C and A + B ${\rightarrow}$ C in liquid solutions examined by the authors in the literature are analyzed and compared with each other for these different types of reactions. It is shown that for a particular case of equal initial concentrations $[A]_0=[B]_0$ in the reaction A + B ${\rightarrow}$ C, when the kinetics of both reactions A + A ${\rightarrow}$ C and A + B ${\rightarrow}$ C in the framework of formal chemical kinetics and ET are the same, the accumulation of macroscopic correlations breaking the concepts of independent encounters and leading to the Generalized Encounter Theory (GET) are drastically different. The influence of the force interaction and the decay of nonstable reactants on the time behavior the macroscopic correlations is also briefly discussed.

Nonclassical Chemical Kinetics for Description of Chemical Fluctuation in a Dynamically Heterogeneous Biological System

  • Lim, Yu-Rim;Park, Seong-Jun;Lee, Sang-Youb;Sung, Jae-Young
    • Bulletin of the Korean Chemical Society
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    • 제33권3호
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    • pp.963-970
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    • 2012
  • We review novel chemical kinetics proposed for quantitative description of fluctuations in reaction times and in the number of product molecules in a heterogeneous biological system, and discuss quantitative interpretation of randomness parameter data in enzymatic turnover times of ${\beta}$-galactosidase. We discuss generalization of renewal theory for description of chemical fluctuation in product level in a multistep biopolymer reaction occurring in a dynamically heterogeneous environment. New stochastic simulation results are presented for the chemical fluctuation of a dynamically heterogeneous reaction system, which clearly show the effects of the initial state distribution on the chemical fluctuation. Our stochastic simulation results are found to be in good agreement with predictions of the analytic results obtained from the generalized master equation.

화학반응속도가 Cu CMP에 미치는 영향 (The effect of chemical kinetics of slurry components on Cu CMP)

  • 정원덕;장원문;박성민;정해도
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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    • pp.372-373
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    • 2006
  • Chemical kinetics affects Cu CMP results (removal rate, Non uniformity etc.) Because Cu is removed by chemical action. Key factors in chemical kinetics are process temperature and concentration of slurry components. In this study, Hydrogen peroxide and citric acid were selected as a oxidant and a complexing agent and Slurry were made by mixing this components. In order to study effects of Chemical Kinetics, X-ray photoelectron spectroscopy (XPS) were performed on Cu sample after etching test as concentration of citric acid and slurry temperature. Finally Cu CMP was performed as same conditions.

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Dimethyl terephthalate와 ethylene glycol의 에스테르 교환 반응 (Transesterification of Dimethyl Terephthalate with Ethylene Glycol)

  • 이진홍;조임표;조상환;조민정;한명완;강경석
    • Korean Chemical Engineering Research
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    • 제51권1호
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    • pp.144-150
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    • 2013
  • 본 연구에서는 촉매로 zinc acetate를 사용하였고 dimethyl terephthalate(DMT)와 ethylene glycol(EG)의 에스테르 교환을 통하여 polyethylene terephthalate(PET)의 단량체인 bishydroxyethyl terephthalate(BHET)를 생성하는 반응에 대하여 알아보았다. 기존의 kinetics 연구는 에스테르 교환 반응에서 생성되는 메탄올이 반응계에서 제거되는 반회분식공정을 바탕으로 하여 이때 제거된 메탄올 양을 측정하여 역반응이 무시된 반응 kinetics 모델을 구성하였다. 본 연구에서는 회분식 반응기를 통하여 DMT와 메탄올의 양을 정량하여, 역반응을 고려한 보다 정확한 kinetics 모델을 제안하였고, 제안된 모델의 예측값들이 실험값들과 잘 일치하는 것을 보였다. 또한 모델과 실험값을 분석하여 여러 공정 변수들이 에스테르 교환 반응에 미치는 영향을 조사하였다.

Kinetics of the Formation of Metalloporphyrins and the Catalytic Effect of Lead Ions and Hydrogen Ions

  • Qi, Yong;Pan, Ji Gang
    • Bulletin of the Korean Chemical Society
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    • 제35권11호
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    • pp.3313-3318
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    • 2014
  • The reaction mechanism of Lead ions catalyzing complexation reactions between TIPP and metal ions was investigated by researching the kinetics of the formation of metalloporphyrins by UV/Vis-spectra, and verified by exploring the formation of metalloporphyrins catalyzed by acetic acid. Kinetics studies suggested that the fluctuations of reaction rate indicated the formation of metalloporphyrin was step-wise, including the pre-equilibrium step (the coordination of the pyrrolenine nitrogens to $Mn^+$) and the rate-controlling step (the deprotonation of the pyrrole proton). In the pre-equalization step, a sitting-atop (SAT) structure formed first with the complexation between larger radius of $Pb^{2+}$ and TIPP, changed the activation, then $Pb^{2+}$ left with the smaller radius of metal ions attacking from the back of the porphyrin ring center. In the rate-controlling step, two pyrrole protons dissociated to restore a stable structure. This was verified by adding acetic acid at different reaction times.

Kinetics of Enriched Chitinase as Extracellular Metabolite in Beauveria bassiana

  • Mondal, Subhoshmita;Datta, Siddhartha;Mukherjee, Alakananda;Bhattacharya, Pinaki
    • 한국미생물·생명공학회지
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    • 제47권1호
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    • pp.96-104
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    • 2019
  • Beauveria bassiana, one of the most common entomopathogenic fungi, has been isolated, pre defined and characterized in-house from soil of tea cultivation area. Experiments have been performed to verify the presence of chitinase as intracellular metabolite and its release as extracellular product rendering the spores with biopesticide activity. Although there are many responsible enzymes for the pest killer action of B. bassiana, binding property of chitinase depending on presence as well as absence of serine supplemented in the media has been studied with respect to the production and kinetics. A programmed investigation conclusively indicates that the isolated spore (hyphae) of B. bassiana has been metabolically enriched with the enzyme chitinase in presence of an externally added amino acid serine with its inhibitory kinetics.