• 제목/요약/키워드: KINETICS

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Vanillylidene imine 유도체의 가수분해 반응에 관한 속도론적 연구 (A study on the Kinetics velocity for hydrolysis reaction of vanillylidene imine derivatives)

  • 성기천;김기준
    • 한국응용과학기술학회지
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    • 제12권2호
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    • pp.145-150
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    • 1995
  • The Kinetics velocity for hydrolysis reaction of vanillylidene imine derivatives has been measured by ultra-violet ray spectrophotometer in 20wt% $dioxane-H_2O$ at $25^{\circ}C$. It was measured the reaction rate Constant of vanillylidene imine derivatives that can be applied widely following to pH-change at $25^{\circ}C$. Final products that hydrolyzed the vanillylidene imine certified in vanillin and aniline derivative, and the effect of substitution radical that has affected on hydrolysis reaction was largely promoted to reaction rate by electron attrating group in acidity and electron donoring group in basic. From the results of rate constant to hydrolysis reaction, substituent radical effect and final products. It has certified the hydrolysis reaction mechanism of vanillylidene imine derivatives.

석탄가스 선회난류 비예혼합 화염장의 화염구조 및 NOx 배출특성 해석 (Numerical Study on Structure and Pollutant Formation for Syngas Turbulent Nonpremixed Swirling Flames)

  • 이정원;강성모;김용모;주용진
    • 한국연소학회지
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    • 제14권2호
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    • pp.10-17
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    • 2009
  • The present study numerically investigate the effects of the Syngas chemical kinetics on the basic flame properties and the structure of the Syngas nonpremixed flames. In order to realistically represent the turbulencechemistry interaction and the spatial inhomogeneity of scalar dissipation rate, the Eulerian Particle Flamelet Model (EPFM) with multiple flamelets has been applied to simulate the combustion processes and NOx formation in the syngas turbulent nonpremixed flames. Validation cases include the Syngas turbulent nonpremixed jet and swirling flames. Based on numerical results, the detailed discussion has been made for the effects of the chemical kinetics, the flame structure, and NOx formation characteristics in the turbulent Syngas nonpremixed flames.

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인공폐에서의 산소전달 속도를 예측하기 위한 아황산용액의 평가 (Evaluation of Sulfite Solution to Predict Oxygen Transfer Rates in Artificial Lung)

  • 이삼철;김기범;정경락
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1998년도 추계학술대회
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    • pp.237-238
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    • 1998
  • The kinetics of sulfite oxidation must be fast and the concentration of sulfite must be low to emulate oxygen uptake by blood. The kinetics were studied yielding a first order rate constant in sulfile, zero order in oxygen. Limitations of the technique were evaluated using the experimental rate constant and an adaptation of Lightfoot's approximation, while the reaction of hemoglobin is reversible and essentially instantaneous, that for sulfite is irreversible and finite. Thus if the approach to saturations not monotonic or if the mass transfer resistance is significantly lowered, e. g. when blood film thicknesses are thinner than a few hundred microns, deviations may occur.

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Modeling Fresh Produce Respiration and Designing Modified Atmosphere Package

  • Lee, Dong-Sun
    • 한국포장학회지
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    • 제13권3_4호
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    • pp.113-120
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    • 2007
  • The method to characterize the fresh produce respiration was presented with possible application of modified atmosphere package design. Particularly the respiration model based on enzyme kinetics was introduced as function of oxygen and carbon dioxide concentrations. The method to estimate the equilibrated package atmosphere for any package conditions was presented by incorporation of $O_2$ and $CO_2$ permeabilities of the packaging film. Temperature dependences for fresh produce respiration and gas permeation were given by Arrhenius equation and then used to analyze the effect of temperature on the package atmosphere. An example analysis was presented for better understanding of the concept.

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Effect of Dealloying Condition on the Formation of Nanoporous Structure in Melt-Spun Al60Ge30Mn10 Alloy

  • Kim, Kang Cheol;Kim, Won Tae;Kim, Do Hyang
    • Applied Microscopy
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    • 제46권3호
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    • pp.160-163
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    • 2016
  • Effect of dealloying condition on the formation of nanoporous structure in melt-spun $Al_{60}Ge_{30}Mn_{10}$ alloy has been investigated in the present study. In as-melt-spun $Al_{60}Ge_{30}Mn_{10}$ alloy spinodal decomposition occurs in the undercooled liquid during cooling, leading to amorphous phase separation. By immersing the as-melt-spun $Al_{60}Ge_{30}Mn_{10}$ alloy in 5 wt% HCl solution, Al-rich amorphous region is leached out, resulting in an interconnected nano-porous $GeO_x$ with an amorphous structure. The dealloying temperature strongly affects the whole dealloying process. At higher dealloying temperature, dissolution kinetics and surface diffusion/agglomeration rate become higher, resulting in the accelerated dealloying kinetics, i.e., larger dealloying depth and coarser pore-ligament structure.

Comparison of explosive compounds (HMX, RDX, and TNT) reduction by micro and nano zero valent iron

  • 배범한
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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    • pp.123-126
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    • 2006
  • Reduction kinetics and intermediates behaviour of three high explosives (HMX, RDX, and TNT) were studies in batch reactors using either nano or micro size zero valent iron(ZVI) as reducing agent. The kinetics constants normalize to the mass of iron($k_M$) or to the surface area ($k_{SA}$) were measured and compared along with the changes of intermediate concentrations of each explosive. Results showed that $k_M$ and $k_{SA}$ values neither correlated each other nor explained the behaviour of intermediates of each high explosive in the batch reactor, in which initial intermediates decreased rapidly with nano ZVI treatment whereas the intermediates accumulated and stayed longer in the micro ZVI treated reactor.

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페놀수지의 마찰특성에 미치는 HEXA의 함량 및 경화도의 영향 (The effect of hexamethylenetetramine contents and cure properties on friction characteristics of phenolic resin)

  • 김대균;장호;윤호규
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1999년도 제30회 추계학술대회
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    • pp.49-56
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    • 1999
  • A material was formulated with Phenol novolac and HEXA only. The cure kinetics and thermal characteristics of phenol novolac with various HEXA contents were peformed by differential scanning calorimetry and thermal gravimetric analysis. All kinetic parameters of the curing reaction including the reaction order, activation energy, and rate constant were calculated and reported. The results indicate that the curing reaction goes through an autocatalytic kinetic mechanism. The friction and wear characteristics of this material were determined using friction material testing machine. The friction coefficient of phenol novolac with various HEXA contents was determined using the PV(pressure & velocity) factor. The most stable and highest friction coefficient with a various pressure and velocity condition was found at HEXA 10 wt.% material. The specific wear rate per unit sliding distance with a various HEXA contents was reported.

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Decursin from Angelica gigas Nakai Blocks hKv1.5 Channel

  • Kwak, Yong-Geun;Choi, Bok-Hee;Kim, Dae-Keun;Eun, Jae-Soon
    • Biomolecules & Therapeutics
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    • 제19권1호
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    • pp.33-37
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    • 2011
  • Decursin was purified from Angelica gigas Nakai, and its effects on the human Kv1.5 (hKv1.5) currents were recorded in mouse fibroblasts ($Ltk^-$ cells) by whole-cell patch-clamp technique. Decursin inhibited hKv1.5 current in a concentration-dependent manner, with an $IC_{50}$ value of $2.7\;{\mu}M$ at +60 mV. Decursin accelerated the inactivation kinetics of the hKv1.5 channel, and slowed the deactivation kinetics of the hKv1.5 current, resulting in a tail crossover phenomenon. Also, decursin inhibited the hKv1.5 current in a use-dependent manner. These results strongly suggest that decursin is a kind of open-channel blocker of the hKv1.5 channel.

The Kinetics of Macrophages, Myofibroblasts and Mast cells in Carbon Tetrachloride - Induced Rat Liver Cirrhosis

  • Jeong, Won-Il;Lee, Cha-Soo
    • 한국수의병리학회:학술대회논문집
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    • 한국수의병리학회 2000년도 추계학술대회 및 정기총회
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    • pp.30-30
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    • 2000
  • Hepatic fibrosis/cirrhosis is characterized by increased production and deposition of collagen, noncollagenous glycaproteins, and proteoglycans, which mainly compose the extracellular matrix (ECM). Recently, activations of macrophages, myofibroblasts and mast cells are thaught ta be associated with the accumulation of ECM. In order to investigate the kinetics of macrophages, myofibroblasts and mast cells and the relationship between these cells and the accumulation of ECM in carban tetrachloride (CCl$_4$)-injected rat liver, we induced liver cirrhosis of rat by an injection of CCl$_4$ for 14 weeks. (omitted)

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