科學敎育 개선을 위한 硏究

崔七男,趙在興,尹晳珍 조선대학교 교과교육연구소 1987 교과교육연구 Vol.10 No.-

고분자물질들의 분극 특성: Poly(vinylchloride), Poly(ethyleneterephthalate), Poly(propylene), Poly(carbonate)

최칠남,양효경,Choi, Chil-Nam,Yang, Hyo-Kyung 대한화학회 2002 대한화학회지 Vol.46 No.1

우리는 고분자 물질들에 대해서 전위와 전류 밀도의 변화를 측정하였다. 온도와 pH를 포함하여 전위와 속도에 대한 영향을 주는 여러 요인들에 밝히기 위하여, 연구 결과들이 주위 깊게 조사되었다. 양극 해리에 대한 Tafel 기울기는 이들 조건 하에서 분극 효과로 결정되었다. 각 경우에 최적 조건들이 확립되었다. 두 번째 양극 전류 밀도 피크와 최대 전류 밀도는 상대적 분극 감도$(I_r/I_f)$로 지정되었다. 최적 조건에서의 분극 효과를 바탕으로, 질량 전달 계수$({\alpha})$는 양극 해리에 대한 Tafel 기울기에 의해서 결정되었다. We measured the variations of potentials and current densities for several polymers. The results were carefully examined to identify various factors such as temperature and pH to influence the potential and rate. The Tafel slope for anodic dissolution was determined by the polarization effect under these conditions. The optimum conditions were established for each case. The second anodic current density peak and maximum current density were designated as the relative polarization sensitivity $(I_r/I_f)$. The mass-transfer coefficient value $({\alpha})$ was determined by the Tafel slope for anodic dissolution on the basis of the polarization effect under optimum conditions.

희토류금속(III) 착물들의 합성과 전자적 구조와 전기화학적 거동에 관한 연구 (II)

최칠남,김세봉,박면용,Chil Nam Choe,Se Bong Kim,Nyon Yong Park 대한화학회 1993 대한화학회지 Vol.37 No.10

란탄나이드 3가($Pr^{3+}$ 와 $Dy^{3+}$)와 유기 리간드를 (phen', terpy') 착물들의 거동을 UV/vis 분광분석, 자기화 그리고 전기화학적 방법에 의해 조사하였다. 착물들의 결정장 갈라짐 에너지 크기와 짝지움에너지 그리고 스핀상태는 착물들의 스펙트라로부터 얻었다. 이들 착물들에 대한 전지화학적 거동은 비수용매속에서 순환 전압전류법에 의해 관찰하였다. 이들 환원피크는 전자 전이에 의한 비가역적인 2단계의 환원 과정이었다. The chemical behavior of trivalent lanthanide ($Pr^{3+}\;and\;Dy^{3+}$) and organo ligands (phen' and terpy') complexes was investigated by the use of UV/vis-spectrophotometric, magnetization and electrochemical method. The magnitude of crystal field splitting energy, the pairing energy and spin state was obtained from the spectra of complexes. These complexes were founded to be diamagnetics, delocalization and low spin complexes. The electrochemical behavior of complexes was observed by the use of cyclic voltammetry in aprotic media. These reduction peaks were irreversible two step reduction processes by electron transfer.

디메틸술폭시드용매 속에서 파라니트로벤젠아조레조르시놀의 폴라로그래피的 還元에 관한 硏究

최칠남,조기형,최주현,Chil Nam Choe,Ki Hyung Jo,Chu Hyun Choe 대한화학회 1986 대한화학회지 Vol.30 No.5

反陽性子性 溶媒인 dimethylsulfoxide中에서 p-nitrobenzeneazoresororcinol<4n-BAR>에 대하여 직류 폴라로그래피적 거동을 조사하였다. 0.05M $NaClO_4$의 DMSO溶媒中에서 4n-BAR은 1電子 2段階의 還元過程을 거쳐 hydrazo기를 포함하는 化合物로 還元된다. 還元反應의 中間 生成物은 比較的 反陽性子性 溶媒 속에서 安定하였다. 各 段階의 還元電流는 擴散支配的이었으며 一部 反應電流도 包含되었다. 酸을 添加함에 따라서 2個의 還元波가 하나로 合致되며 [acid]/[reductant]의 몰 (M)비가 M = 2인 條件에서 加電位(-E)에 대해 $log(i_d-i)(Mi_d/2-i)/i$/의 可逆性은 1電子 2段階 還元反應이고 非可逆的이었다. The direct current polarographic behavior of 4n-BAR in dimethylsulfoxide as an aprotic solvent have been investigated. The reduction of 4n-BAR in 0.05M sodium perchlorate solution proceeds along two one-electron steps to give the corresponding compound containing hydrazo groups, each reduction wave was considerably diffusion controlled and irreversible. By addition of acid HAc to 4n-BAR in DMSO solvent, the two reduction waves have coalesced into one in the condition M $\geq$ mole ratio, acid/reductant(M = 2), the slope of $log(i_d-i)(Mi_d/2-i)/i$/ vs. (-E) is irreversible along one-electron steps reduction waves.

Alizarin Yellow에 依한 微量 As의 吸光度 測定

崔七男,丁梧鎭 조선대학교 기초과학연구소 1979 自然科學硏究 Vol.2 No.1

This paper is attempted to discuss an analysis of a sample and rapid Spectrophotometric method without particular apparatus or difficult procedures. We dropped 1 ml of Alizarine Yellow solution into 25 ml of the Arsenic solution and that PH was adjusted to 10 with Sodium Hydroxide. At PH 10, alizarin yellow reacted with Arsenic developed the stable color with good reproducibility after an hour in water at 25℃. An essentially linear relationship to the Arsenic was observed in the range of 1 ㎍-40 ㎍ at 745 nm, an it was established that the number of absorbing species in the reaction system was only between 700 nm and 750 nm. Among the interferences. arsenic material could be removed by the addition of metanol. One hour's standing did not chnge a bit in the absorbance. The mole ratio of Alizarin Yellow in the complex under given condition was 1:1.

알칼리 토금속족 탄산염-티탄산염 및 지르콘산염 합성과 열적성질

최칠남,정오진,윤석진 조선대학교 기초과학연구소 1982 自然科學硏究 Vol.4 No.2

CaTiO_3, SrTiO_3, BaTiO_3, CaZrO_3, SrZrO_3 and BaZrO_3 were synthesized by soild state reacion and mixing method of partial precipitation according to the various reaction time sand heating temperatures. These synthetic compounds were identified by X-ray diffractometer (ShimadzuVg-1 Type, Japan) and the production ratios (α) were calculated for the intensity of X-ray diffraction. The thermal properties of synthsized compounds were checked by Differential Thermal Analyzer (Shimadzu DT-2B Type). The change of loss in weight and reaction mechanism were discussed at various transition temperatures. The results were as follows: 1) The synthetic conditions used in the method of partial precipitation were above 1100℃ in heating temperature and two hours in heating time. 2) Alkaline earth metal groups used to produce synthetic compounds change from liquid state to solid. It was predicted to react to titanium dioxide and zirconium dioxide at about 950℃ to from stable compounds at about 1,400℃. 3) Production ratios of the reaction were directly proportional to the heating temperature. 4) The loss in weight in the mixed systems of titanium dioxide resulted from the phase change of carbonate. 5) A relation between reaction time and production ratio of the reaction increased almost linearly up to about two hours, and the reaction reate were measured according to the slope.

Cd(Ⅱ) 폴라로그람의 異常波에 關한 硏究

崔七男,朴聖珪,丁梧鎭,문경국 조선대학교 기초과학연구소 1984 自然科學硏究 Vol.7 No.1

pH 6.0∼12.0 範圍에서 0.15M 타르타르 酸鹽支持溶液 속에서 Cd(Ⅱ) Polarogram을 25℃에서 二段還元波를 調査한 결과 pH8.2部分 까지는 限界電流 및 半波電位값이 一定하며 한편 같은 濃度의 窒酸鹽 支持溶液을 사용하였을 때에 比하여 一段還元波의 半波電位값은 0.03volt 陰의 電位값으로 移動하고, 限界電流 값은 21% 減少되었다. pH8.2 部分 以上부터 限界電流 값이 急激하게 增加하다가 pH8.9 以上부터는 다시 急激하게 減少하는 現象을 보여 주었다. 한편 pH8.2 以上부터는 半波電位가 pH11.0에서는 -1.37volt로 되었다. 可能한 電極反應을 假定하여, pH11.0에 이르기까지의 還元波移動의 原因을 檢討하였다. The second reduction waves of the polarogram of Cd(Ⅱ) in 0.15M sodium tartrate solution were investigated in the range of pH from 6.0 to 12.0 at 25 C. Up to pH 8.2, the limiting current and the half wave potential were found to be constant, and when compared with the nitrate solution equal to the concentration of sodium tartrate, the limiting current of the first reduction wave has been decrease 21% and the half wave potential of the first reduction wave shifted by -0.03 volt. The values of limiting current were sharply increased above pH 8.2, and maximum value was obtained at pH 9.8. The half wave potentials were gradually proceeded in negative direction with increasing pH and the half wave potential of -1.37 volt was obtained at the pH 11.0. Suggesting possible mechanisms of electrode reactions, the anomalous behavior of reduction waves of Cd(Ⅱ) in sodium tartrate solution up to pH 11.0 was discussed.

희토류금속(Ⅲ) 착물들의 합성과 전자적구조 그리고 전기화학적 거동에 관한 연구

崔七男,金世奉,金一斗 조선대학교 기초과학연구소 1994 自然科學硏究 Vol.17 No.1

디피바로일메탄올을 가지고, Pr(Ⅲ) 와 Eu(Ⅲ)착물들에 대한 화학적 거동은 U.V/vis 분광분석, 자기학적 그리고 전기화학적 방법으로 조사였다. 착물들의 결정장 갈라짐 에너지 크기와, 스핀 짝지움 에너지 그리고 스핀상태는 스펙트라 로부터 얻었다. 낮은 스핀상태에 있는 두 경우 (4f^2 과 4f^2궤도함수)가 각각 가능했고, 이들 상태는 착물들의 갈라짐 에너지로부터 얻어졌다. Pr(Ⅲ)와 Eu(Ⅲ)의 팔면체 착물들은 ^3F-^3P 와 e_g-b_1g 전위에 일치하는 3개의 스핀 허용 d-d 전위가 나타날 것으로 예상되어진다. 이들 착물들은 상자기성과 비편재화 그리고 낮은 스핀 상태임을 알게 되었다. 착물들의 전기 화학적 거동은 비수용액 속에서 순환 전압 전류법에 의해 관찰 되었다. 이들 환원 피크는 비가역적인 두 단계 환원과정 이었다. The chemical behavior of preseodymium (Ⅲ) and europium (Ⅲ) complexes with dipivaloylmethane was investigated by the use of U,V/vis-spectrophotometry, magnetometry, and electrochemical method. The magnetitude of crystal field splitting energy, the spin pairing energy, and spin state of complexes was obtained from the spectra. For each of the two eases (4f^2 and 4f^6 orbital) where low-spin state are possible, these state were obtained from the splitting energy of complexes. An octahedral complexes of Pr(Ⅲ) and Eu(Ⅲ) would be expected to exhibit three spin-allowed d-d transition, corresponding to the transition ^3F-^3P and e_g-b_1g. These complexes found to be paramagnetics, delocalization, and low-spin state. voltammetry in aprotic media. These reduction peak were irreversible two stop reduction processes.

고분자 물질들의 특성: Poly(vinylchloride), Poly(ethyleneterephthalate),Poly(propylene), Poly(carbonate)

최칠남,양효경 대한화학회 2002 대한화학회지 Vol.46 No.1

알칼리 토금속족 탄산염-티티산염 및 지르콘산염 합성과 열적성질

최칠남,정오진,윤석진 朝鮮大學校 自然科學硏究所 1982 自然科學硏究 Vol.5 No.-

CaTiO_(3), SrTiO_(3). BaTiO_(3), CaZrO_(2), SrZrO_(3) and BaZrO_(3) were synthesized bv soild state reacion and mixing method of partial precipitation according to tbe various reaciion time sand heating temperatures. These synthetic compounds were identified by X-ray diffractometer (SidmadzuVG-l Type, Japan) and the producion ratios (α) were calculated for the intensity of X-ray diffraction. The thermal properties of synthsized compounds were checked by Differcntial Thermal Analyzer (Shimadzu DT-2B Type). The change of loss in weight and reaction mechanism were discussed at various transition temporatures. The results were as folIows: 1) The synthetic conditions used in the method of partial precipitation were above 1100℃ in heating temperacure and two hours in heating time. 2) Alkaline earth metal groups used to produce syiuhetic compounds change from liquid state to solid. It was prodicted to react to titanium dioxide and zirconium dioxide at about 950℃ to from stable compounds at about 1,400℃. 3) Production ratios of the reaction were dirsctIy proportional to the heating temperature. 4) The loss in weight in the mixed systems of tknntum dioxide resulted from the phase change of carbonate. 5) A relation betwecn reacdon time and produecion raetos of the reaction increased almost linearly up to about two hours, and the reaction rate were measured according to the slopc.