• Bulletin of the Korean Chemical Society
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• 제17권7호
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• pp.653-655
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• 1996

A comparative molecular field analysis (CoMFA) was carried out for the correlation of the transition state structures and the reaction rates for the SN2 reaction of 4-nitrophenyl benzoate and its sulfur analogs with anionic nucleophiles. The CoMFA analysis showed that both steric and electrostatic effects are important, and the steric contribution increased when nucleophiles are alkoxides or arylsulfides. In this study, we have demonstrated that the CoMFA analysis can be expanded beyond the scope of dealing with reactants and products. The reactant complex and transition state conformations generated along the reaction path can be more appropriately used for the correlation of structures and reaction rates.

• 대한화학회지
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• 제49권1호
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• pp.105-111
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• 2005

• 대한화학회지
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• 제20권5호
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• pp.333-339
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• 1976

여러가지 조성의 물-아세톤 및 물-에탄올 혼합용매 속에서 2-염화테노일의 가용매 분해반응속도를 20 ∼ $40^{circ}C$에서 측정하여 활성화 파라미터를 계산하고 Winstein 그림표의 기울기와 혼합용매조성에 따른 속도 상수 상수의 변화를 검토하였다. 실험결과 혼합용매의 물함량이 증가할 수록 $S_N1$ 반응성이 강하게 나타남을 보았다. 그러나 염화벤조일의 가용매 분해반응속도 보다는 느림을 알았다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 추계 기술심포지움
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• pp.134-137
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• 2001

The cure kinetics of a cycloalipatic epoxy / anhydride / Co(II) system for a no-flow underfill encapsulant, has been studied by using a differential scanning calorimetry(DSC) under isothermal and dynamic conditions over the temperature range of $160^{\circ}C ~220^{\circ}C$. The kinetic analysis was carried out by fitting dynamic/isothermal heating experimental data to the kinetic expressions to determine the reaction parameters, such as order of reaction and reaction constants. Diffusion-controlled reaction has been observed as the cure conversion increases and successfully analyzed by incorporating the diffusion control term into the rate equation. The prediction of reaction rates by the model equation corresponded well to experimental data at all temperature.

• Bulletin of the Korean Chemical Society
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• 제20권4호
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• pp.392-394
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• 1999

• 한국광물학회지
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• 제10권1호
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• pp.33-44
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• 1997

The reaction path of water-gneiss in 200m borehole at the Soorichi site of Yugu Myeon, Chungnam was simulated by the EQ3NR/EQ6 program. Mineral composition of borehole core and fracture-filling minerals, and chemical composition of groundwater was published by authors. In this study, chemical evolution of groundwater and formation of secondary minerals in water-gneiss system was modelled on the basis of published results. The surface water was used as a starting solution for reaction. Input parameters for modelling such as mineral assemblage and their volume percent, chemical composition of mineral phases, water/rock ratio reactive surface area, dissolution rates of mineral phases were determined by experimental measurement and model fit. EQ6 modelling of the reaction path in water-gneiss system has been carried out by a flow-centered flow through open system which can be considered as a suitable option for fracture flow of groundwater. The modelling results show that reaction time of 133 years is required to reach equilibrium state in water-gneiss system, and evolution of present groundwater will continue to pH 9.45 and higher na ion concentration. The secondary minerals formed from equeous phase are kaolinite, smectite, saponite, muscovite, mesolite, celadonite, microcline and calcite with uincreasing time. Modeling results are comparatively well fitted to pH and chemical composition of borehole groudwater, secondary minerals identified and tritium age of groundwater. The EQ6 modelling results are dependent on reliability of input parameters: water-rock ratio, effective reaction surface area and dissolution rates of mineral phases, which are difficult parameters to be measured.

• Bulletin of the Korean Chemical Society
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• 제10권5호
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• pp.448-452
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• 1989

NADH analogs, 1-benzyl-3-substituted (X)-1,4-dihydropyridines 1-4 (1: X = $CONH_2$; 2: X = $CSNH_2$; 3: X = $COOCH_3$; 4: X = $COCH_3$) were synthesized. The second order rate constants for hydration reaction and oxidation reactions by $Cu^{2+}$, $Fe(CN)_6^{3-}$ or methylacridinium iodide (MAI) of the compounds were determined. For all reactions investigated, the rate constants increased with decreasing electronegative character of the 3-substituents of 1,4-dihydropyridines : the decreasing order of the reaction rates was 2>1>3>4. However, the sensitivity of the reaction rates on the 3-substituents differed among the reactions. This was explained in view of mechanisms of the reactions.

• Korea-Australia Rheology Journal
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• 제19권1호
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• pp.7-16
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• 2007

A dynamic Monte Carlo percolation grid simulation is used to predict the cure behaviour of thermoset materials. Molecules are distributed in a fixed grid and a probability of reaction is assigned to each pair of neighbouring units considering both reaction rates and diffusion. The concentration and network characteristics are predicted throughout the whole curing process and compared to experimental data for an epoxy-amine matrix.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1289-1292
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• 2005

• 한국연소학회지
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• 제5권1호
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• pp.7-18
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• 2000

Numerical simulations of counterflow non-premixed $CH_4/C_2HCl_3/Air$ flames added 8%(by volume) C2HCl3 on the fuel side are conducted at atmospheric pressure using a detailed chemical reaction mechanism in order to understand the effect of strain rates. A detailed sensitivity analysis is also performed in order to assess the relative influence of each reaction on the flame established at a strain rate of 200s-1. The structure of flames (i.e., temperature, velocity, and concentration of species) established at both a strain rate of 150s-1 and 300s-1 are investigated. As the strain rate increases, the "flame zone" is restricted to a narrower range and the position of maximum temperature is shifted to the fuel side. The concentrations of major species, H2O, CO, H2, HCl, Cl2, and Cl are decreased with increased strain rate. The reaction involving chlorine, CH4 + Cl $\rightarrow$ CH3 + HCl, instead of the reaction, CH4 + H $\rightarrow$ CH3 + H2 influences the consumption of methane. C2HCl3 + OH $\rightarrow$ CHCl2 + CHOCl and HCl + OH $\rightarrow$ H2O + Cl, are major reactions, through which OH radicals are consumed.