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Understanding on chemical behavior of iodine species under gamma irradiation condition
연제원 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
The chemical behavior of iodine has been studied because iodine has various oxidation states. In particular, iodine species can be oxidized or reduced under gamma irradiation. In this work, I investigated the effects of the water radiolysis on the formation of molecular iodine and methyl iodide. First, the effect of gamma irradiation was studied on the pH change of pure water. In general, the water decomposition does not change the solution pH. However, the pH can be changed when some chemicals are present in the irradiated solutions. Second, I examined the oxidation of iodide by hydroxyl radical and hydrogen peroxide. The roles of hydrogen peroxide were analyzed electrochemically for the oxidation of iodide ion and the reduction of iodine. Third, I studied on the formation of methyl iodide under gamma irradiation. The methyl iodide was observed at the pH below 6.4, but it was found that the low pH was not a sufficient condition for the formation of methyl iodide.
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전기화학적 wet/dry 법을 이용한 탄소강의 대기부식에 미치는 상대습도의 영향에 관한 연구
연제원,변수일,이우진,최인규,전관식,Yeon Jei-Won,Pyun Su-Il,Lee Woo-Jin,Choi In-Kyu,Chun Kwan-Sik 한국전기화학회 2000 한국전기화학회지 Vol.3 No.1
In the present work, corrosion rate W and corrosion potential tow were simultaneously measured as a function of relative humidity RH employing the electrochemical wet and dry method as an accelelated atmospheric corrosion method. The W versus (vs.) RH curve is classified into .three regions, namely, the first W plateau region, the second region of the linear relationship between logarithmic W and RH, finally, followed by an abrupt decay region. Based upon the atmospheric corrosion mechanism of mild steel, we introduced another diagram of $\varepsilon_{corr}$ vs. RH which is divided into three regions. In the first region, the corrosion scales are composed of single lepidocrocite-phase $(\gamma-FeOOH)$; in the second region, $\gamma-FeOOH$-phase coexists with magnetite-phase $(Fe_3O_4)$ in the scales and finally the oxide scales change into a single Fe304-phase in the third region. The three distinct regions of both representations share almost each other, which is validated by FT-IR (Fourier transform infra-red) analysis and surface observation. Both representations prove to be convenient and complementary for surveying the spectrum of the atmospheric corrosion of mild steel.
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정상상태 회전원판전극(RDE) 방법과 유체역학적 요동에 의한 전기화학적(EHD) 임피던스방법을 이용한 금전극표면에 형성된 PVC 피막내 산소확산계수의 온도의존성에 대한 연구
연제원,변수일,이우진,최인규,Yeon Jei-Won,Pyun Su-Il,Lee Woo-Jin,Choi In-Kyu 한국전기화학회 2000 한국전기화학회지 Vol.3 No.1
In the present we.k, temperature dependence of oxygen diffusivity in the polyvinyl chloride (PVC) film $D_f$ formed on gold electrode was investigated using steady-state rotating disk electrode (RDE) technique and modulated electrohydrodynamic (EHD) impedance technique. Both the diffusion rate defined as the ratio of oxygen diffusivity in the PVC film to the film thickness $D_f/\delta_f$ and the time constant $\delta_f^2/D_f$ for oxygen diffusion through the PVC film were obtained from plot of the limiting current versus disk rotation speed and from filing the EHD impedance spectra experimentally measured to those theoretically calculated on the basis of the diffusion equation for mass transport through the non-conductive and porous film, respectively. By combining measured $D_f/\delta_f$ with $\delta_f^2/D_f$, we determined $\delta_f\;and\;D_f$ at room temperature separately. As temperature increased, it appeared that the $D_f$ value measured for the PVC film-covered gold RDE was enhanced more rapidly than that $D_s$ value in the solution measured for the PVC film-free gold RDE. This means that the pores glowing with increasing temperature act as effective diffusion paths within the film. The present in-situ steady-state and modulated EHD measurements prove to be effective for determining $\delta_f\;and\;D_f$, separately and at the same time the porosity of the PVC film at temperatures below glass temperature $T_g$ of the film.
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붕산수용액 매질에서 용존수소와 과산화수소의 고온 전기화학 거동연구
연제원,우승균,최영구,정용주,김원호,Yeon Jei-Won,Woo Seung-Kyun,Choi Young-Ku,Jung Yongju,Kim Won-Ho 한국전기화학회 2004 한국전기화학회지 Vol.7 No.1
The electrochemical behaviors of dissolved hydrogen and hydrogen peroxide at a platinum disk electrode were investigated in boric acid solution by potentiostatic polarization method at the temperature of 25 and $200^{\circ}C$. The oxidation of dissolved hydrogen at $25^{\circ}C$ was kinetically controlled reaction, the rate of which depends upon the electron transfer on the electrode surface. As temperature was raised, however, the electrochemical characteristics of dissolved hydrogen were changed from a kinetically controlled reaction to a diffusion controlled one. One notable feature, with dissolved hydrogen at high temperature, is that an abnormal potential range was observed, where the oxidation rate of dissolved hydrogen rapidly decreased just before starting potential of water oxidation. We think it is caused by the deactivation of the electrode that results from the adsorption of hydroxyl ion on the surface of the platinum disk. On the contrary, a definite change with temperature was not identified in the case of the hydrogen peroxide except for the increase in current density that was due to the increasing diffusion coefcient with an increase of temperature.
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연제원,정상혁 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.8
As a part of evaluating the volatility of iodide ions subjected to gamma irradiation, I2 evaporation experiments were performed with I2 and I- mixed solutions in the temperature range 26-80℃ in an open, well-ventilated space. The evaporation of I2 was observed to follow primarily first order kinetics, depending on the I2 concentration. The evaporation rate constant increased rapidly with increase in temperature. The presence of Ie slightly reduced the evaporation rate of I2 by forming relatively stable I- 3 . The effect of Cl- at <1.0 wt% on I2 evaporationwas insignificant. The evaporation rate constants of I2 were 1.3 × 10-3 min-1 cm-2, 2.4 × 10-2 min-1 cm-2, and 8.6 × 10-2 min-1 cm-2, at 26℃, 50℃, and 80℃, respectively.
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연제원(Jewon Yeon),이강찬(Kangchan Lee),이규철(Kyuchul Lee),나중찬(Jungchan Na),이미영(Miyoung Lee) 한국정보과학회 1999 한국정보과학회 학술발표논문집 Vol.26 No.2Ⅰ
최근 들어 XML에 대한 연구가 늘어나면서, XML(eXtensible Markup Language)문서에 대한 저장/검색에 대한 다양한 방법들이 제시되고 있다. 특히 XML 문서의 구조적인 특성을 살리면서 문서의 저장 및 변경을 원할하게 지원할 수 있는 방안에 대한 요구가 늘고 있다. 기존의 저장관리 시스템을 위한 저장 모델로는 크케, XML문서의 빠른 검색을 지원할 수 있는 가상분할모델(Virtual Fragmentation Model)과, 문서에 대한 변경을 빠르게 지원해 줄 수 있는 분할모델(Decomposition Model)로 나누어 볼 수 있는데, 본 연구에서는 이 두 가지 모델의 장점을 취합하여 문서의 검색 속도는 가상분할모델정도로, 문서의 변경 속도는 분할모델정도로 빠르게 지원 해 줄 수 있는 페이징(Paging)기법에 대해 설계하였다. 본 페이징 기법은 XML문서뿐만 아니라, 문서 구조상 여러 개의 노드(또는 엘리먼트)로 구성되는 SGML(Standard Generalized Markup Language)이나 HTML(HiperText Markup Language)문서의 저장관리 시스템에서도 똑같이 적용 될 수 있다. 본 연구의 후반부에서는 페이징기법과 다른 기법에 대한 비교를 통하여 페이징 기법의 성능을 분석하였다.
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