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Sakong Yeol,Yoo Seoung-Kyo,Lee Ikchoon Korean Chemical Society 1992 Bulletin of the Korean Chemical Society Vol.13 No.6
Preferential solvation (PS) phenomena of solutes based on solvent polarity, $E_T$ and AN, were studied by UV/vis. and NMR spectra in MeOH binary mixtures. According to the extent of solvent-solvent interaction, different solvation phenomena were found. PS concept was applied to explain the reactivity of tert-butyl halides solvolysis. The findings of solvation phenomena have been related to the rate of solvolysis and PS suggested as a reason for the solvent dependence of the rates of reaction. Moreover, we found that the results of principal components analysis using six parameters are in good accordance with the results of PS phenomena in mixed methanol systems.
Yeol Sakong,Shi Choon Kim,Jin Sung Kim,Ikchoon Lee Korean Chemical Society 1990 Bulletin of the Korean Chemical Society Vol.11 No.2
The Gutmann acceptor number(AN), solvatochromic parameters $({\alpha},{\beta}\;and\;{\pi}^{\ast})$ and hydrogen bonding equilibrium constants (KHB) were determined for three binary systems of methanol with 1,2-dimethoxyethane(DME), 1,2-dichloroethane(DCE) and pyridine (PYD). The solvolysis rate constants of t-butyl chloride, bromide and iodide were also determined in the three binary systems. Solvent properties and solvolysis rates have been discussed in the light of various solvent parameters. Solvolysis of t-butyl halides are most conveniently explained by the two-stage mechanism involving ion-pair intermediate with the ion-pair formation for chloride and ion pair dissociation for iodide as rate limiting.
고압 가용매 분해반응의 물성 연구 : 메독 시벤질클로라이드의 가용매 분해반응에 대한 압력의 영향
사공열,경진범,권오천,최기준 漢陽大學校 基礎科學硏究所 1985 基礎科學論文集 Vol.4 No.-
p-메독시벤질클로라이드의 가용매 분해반응속도를 10℃에서 압력을 1~1200bar로 변화시키고 에탄올-물 혼합용매의 조성이 0∼0.40인 에탄올 몰 분율의 범위내에서 전기전도도법으로 측정하였다. 이 반응의 속도상수로부터 활성화파라미터, ??를 구한 결과 혼합용매의 몰 분율이 0.30 부근에서 extremum behavior를 나타내었다. 이러한 현상을 기저상태와 전이상태의 용매구조변화로 논의했다. 그리고 가용매 분해속도와 에탄올-물 혼합용매의 유전상수를 Kirkwood 식에 적용하고, 전이상태에서 반응에 관여한 물 분자수를 계산하여 그에 따른 반응메카니즘을 고찰하였다. The rates of solvolysis for p-methoxybenzyl chloride have been measured by an electric conductivity method in aqueous ethanol from 0 to 0.40 mole fraction of ethanol under various pressures up to 1200 bar at 10℃. The activation parameters, ??, ?? are evaluated from the rate constants. The results indicated that values of ?? and ?? exhibit extremum behaviors near 0.30 mole fraction of ethanol. These behaviors are discussed in terms of solvent structure variation of ground state and transition state. The rate of solvolysis and the dielectric constant of aqueous ethanol are compared with the reaction mechanism of p-methoxybenzyl chloride by Kirkwood equation. And the reaction was discussed from the number of H₂O molecule participated in the transition stat
司空烈 漢陽大學校 基礎科學硏究所 1981 基礎科學論文集 Vol.1 No.-
The permselectivity, ion activity measurement and other electrochemical properties of various ion exchange membrane were studied extensively by previous workers. In the present work, the following investigations have been done for some of cation or anion membranes: 1. The qualitative relation between the change of transference numbers in membrane and concentration of solution. 2. The validity of eq. ?? in univalent system. 3. Concentration potential for measurement of activity and study of pachment paper properties. The cell diagram in this work; Hg|Hg₂Cl₂, sat.KCl||solu. α₁ membrane solu. α₂ || sat. KCl, Hg₂Cl₂|Hg is similar to those adopted by previous workers. From these investigations, the following conclusion has been made: 1. The transference number in ion exchange increase as the concentration of solution decrease, and below 0.002N the number remains almost unchanged. 2. The ratio of ion mobility in membrane was constant whe the concentration of solution was bolow 0.5N. 3. Relaton between ??and ?? was found to be ??. From this equation, it is possible to obtain the activity of various KCl solutions.
아세톤 溶液內에서의 1-Phenethyl Chloride의 할로겐 交換反應에 관한 速度論的 硏究
司空烈 漢陽大學校 1975 論文集 Vol.9 No.-
Kinetics of halogen exchange reaction of 1-phenethyl chloride using radioisotopic tracer halide ions in acetone have been studied. The rate constant was determined at two temperature and the activation parameters, ?? and ?? were calculated. The reactions were believed to be ?? processes and the orders of relative nucleop- hilicity of halide ions were ??. The reaction rate is slower than that of benzyl chloride. These were interpreted in terms of so1vation effect of halide ions and HSAB principle.
용매효과변수들에 의한 메탄올 이성분 혼합용매들의 반응성에 관한 연구
사공 열,류승교 漢陽大學校 基礎科學硏究所 1993 基礎科學論文集 Vol.12 No.-
용매의 polarity변수인 ??와 AN으로부터 MeOH-MeOH, MeOH-MeCN 및 MeOH-DCE 혼합용매들의 용매화 현상을 UV/vis 및 NMR분광기를 이용하여 측정하였다. 용매화 현상은 용질-용매간 상호작용의 정도에 따라 다르게 나타났으며, 이러한 용질의 선호적 용매화는 t-butyl halides의 가용매분해반응의 반응성 해석에 적용되었다. 결과들은 가용매분해반응의 반응속도와 관계될 뿐 아니라 용매화 현상은 반응속도의 용매의존에 대한 하나의 중요한 요인임을 알 수 있었다. Solvation phenomena of solutes based on solvent polarity, ??-and AN, were studied by UV/vis and NMR spectra in MeOH-MeOH, MeOH-MeCN and MeOH-DCE mixtures. According to the extent of solute-solvent interaction, different solvation phenomena were found. Preferential solvation of solutes was applied to explain the reactivity of t-butyl halides solvolysis. The findings have been related to the rate of solvlysis and solvation phenomena is suggested as a reason for the solvent dependence of the rates of reaction.
정동열(Dong-yeol Jung),홍성수(Sung-Soo Hong),최병조(Byung-Cho Choi),사공석진(Sug-Chin Sakong) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
Two existing continuous-time models for the current-mode control have presented noticeable differences in their small-signal predictions. As an attempt to clarify the origin of these disparities, this paper presents an alternative way of deriving a continuous-time model for the current-model control The results of this paper would provide insights to comprehend the dissimilarity in the modeling method and final results of the earlier models of current-mode control