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흐름계를 이용한 크롬도금 용액의 Cr(Ⅲ)와 Cr(Ⅵ)의 분광학적 동시 분석 방법
김선관,남학현,소재춘,이원,차근식,한상현,Kim, Sun Kwan,Nam, Hakhyun,So, Jae Chun,Lee, Won,Cha, Geun Sig,Han, Sang Hyun 대한화학회 1995 대한화학회지 Vol.39 No.2
크롬도금 용액에 공존하고 있는 Cr(III)와 Cr(VI)의 양을 자외선/가시광선 분광기에 장착한 흐름계 장치를 이용하여 시료당 5분 이내에 두 가지 물질의 양을 동시에 분석하는 방법을 개발하였다. Cr(III)와 Cr(VI)는 각각 580 nm와 440 nm에서 0.05 g/L와 0.005 g/L 이상의 범위에서 Beer-Lambert 법칙에 따르는 특성 ${\lambda}_{max}$를 나타내며, 이 파장들에서의 흡광도는 pH<4의 조건에서는 pH변화에 거의 영향을 받지 않았다. 따라서 일반적으로 크롬의 농도가 수 g/L인 후처리 크롬 도금조의 용액을 흐름계의 장치에서 pH=1의 황산 용액으로 묽힌 후, 자외선/가시광선 분광기로 측정하면 Cr(III)와 Cr(VI)의 양 및 총 크롬의 양을 기존의 산화-환원 적정 방법(최소 40분/sample)보다 간편하고 신속정확하게 동시 정량할 수 있었다. 이 장치는 설치 및 사용이 간단하고, 설치 비용이 저렴하므로 많은 도금 산업 현장에서 용이하게 응용할 수 있다. The amount of Cr(Ⅲ) and Cr(Ⅵ) in a chromium plating solution could be determined simultaneously within five minutes using UV/VIS spectrophotometer coupled with a flow-through analysis(FTA) setup. The λmax's at 580 nm and 440 nm which correspond to Cr(Ⅲ) and Cr(Ⅵ), respectively, well obey the Beer-Lambert law in the range over 0.05 g/L for Cr(Ⅲ) and 0.005 g/L for Cr(Ⅵ). when the pH of the sample is less than 4.0, the absorption extinction coefficients of those peaks are not much dependent on the proton concentration. The amount of Cr(Ⅲ) and Cr(Ⅵ), and the total chromium in post treatment chromium plating solution, which normally has few g/L of Cr concentration, could be easily measured using UV/VIS spectrophotometry after the sample had been diluted with sulfuric acid of pH=1.0 in the flow-through analysis setup; this method is far more convenient and faster than the common redox titration (which requires at least 40 min/sample) method, while the accuracy of the method is highly comparable to conventional titrimetric method. Since the implementation of an PTA-UV/VIS setup in any plating industry is cost effective and easy to operate, the analytic method described in this paper may be applied directly for in situ analysis of plating solutions.
용접 모니터링을 활용한 SS400강의 GMAW 혼합가스 조성에 따른 용접부의 기계적 특성에 관한 연구
김선관(Sun-Kwan Kim) 산업기술교육훈련학회 2011 산업기술연구논문지 (JITR) Vol.16 No.4
Rolled steel(SS400, 9mm) and welding rod of 1.2mm solid wire were used to fix current, voltage and gas flux via GMAW welding, pre-welding test with the optimal conditions were used for welding monitoring and the rate of gas compound (CO2 100%, CO2 25%+Ar75%, CO2 50%+Ar50%, CO2 75%+Ar25) was changed for auto welding. Each test measured sealing intensity, stretching rate, hardness and shocking degree, while optic microscope observed change of metal structure to see the influence of gas compound change on the mechanical feature; which resulted in the following. 1. Sealing intensity of weld metal zone was the highest at CO2 50%+Ar50% and the lowest at CO2 75%+ Ar25%, while stretching rate was in inverse proportion to the sealing intensity. 2. Sharpy impact value was the highest at 0℃ and Ar 50%, which was the same as sealing intensity and hardness. 3. Hardness of weld metal zone was the highest when Ar50% was mixed, which was higher in case of CO2 100%. 4. As a result of observing structure, it showed general welding part of ferrite and bainite; and ferrite structure slightly increased while bainite decreased, as Ar gas increased.
답토양중(畓土壤中) Cadmium의 형태별(形態別) 분포(分布)와 현미중(玄米中) Cadmium 함량(含量)과의 관계연구(?係硏究)
임선욱,김선관,Lim, Sun-Uk,Kim, Sun-Kwan 한국토양비료학회 1983 한국토양비료학회지 Vol.16 No.1
연(鉛) 아연광산(?鉛?山) 인근답중(隣近畓中) Cd오염(汚染)이 심(甚)할 것으로 여상(予想)되는 지점(地点) 36개소(個所)에서 토양(土壤)과 현미(玄米)를 수도수확기(水稻收穫期)에 동시(同時)에 채취(採取)하여 토양중(土壤中) Cd을 $KNO_3$ 침출성(浸出性)(치환태(置換態)), NaF 침출성(浸出性)(흡착태(吸着態)), $Na_4P_2O_7$ 침출성(浸出性)(유기태(有機態)), EDTA 침출성(浸出性)(Carbonate태(態)), $HNO_3$ 침출성(浸出性)(Sulfide태(態)), 비침출성(非浸出性)(불용태(不溶態))로 분별분석(分別分析)하여 이들 형태(形態)의 Cd과 토양특성(土壤特性)과 관계(?係) 및 현미중(玄米中) Cd 함량(含量)과의 관계(?係)를 조사(調査)한 결과(結果)는 다음과 같다. 1. 형태별(形態別) Cd 분포비(分布比)는 토양특성(土壤特性)에 따라 차이(差異)가 심(甚)하나 평균치(平均値)를 보면 유기태(有機態)가 대략 44%, 불용태(不溶態)가 약 6%, 기타형태(其他形態)는 10~15% 범위(範?)였다. 2. pH가 높은 토양(土壤)일수록 치환태(置換態) Cd은 낮아지나 유기태(有機態) 및 Carbonate태(態) Cd은 증가(增加)하는 경향(傾向)이고 타형태(他形態)의 Cd은 pH에 따른 변화(?化)를 보이지 않았다. 3. 유기물(有機物) 함량(含量)이 높은 토양(土壤)일수록 유기태(有機態) Cd만 增加하고 흡착태(吸着態)를 제외(除外)한 다른 형태(形態)의 Cd은 감소(減少)하는 경향(傾向)이었다. 4. CEC와 Cd 형태별(形態別) 분포(分布)와의 관계(?係)는 유기물(有機物) 함량(含量)에 따른 Cd의 분포양상(分布樣相)과 유사(類似)하였다. 5. 현미중(玄米中) Cd은 유기태(有機態) Cd과 가장 높은 정(正)의 상관(相?)을 보였으며, Carbonate태(態) Cd도 유의성(有意性)있는 정(正)의 상관(相?)을 보였으나 다른 형태(形態)의 Cd와는 유의성(有意性)있는 상관(相?)을 보이지 않았다. The object of this study was to investigate the distribution of Cd fractions in paddy soils in relation to some soil characteristics and to find out the relationships between soil Cd fractions and Cd content in brown rice. Thirty six soils and rice samples were collected from the paddy field adjacent to zinc mining sites at harvest time in 1981. Total Cd content of brown rice samples was analyzed. A sequential extraction procedure was used to fractionate Cd in soils into the designated forms of exchangeable, adsorbed, organically bonded, carbonate, sulfide, and residual Cd. The results obtained were as follows: 1. The distribution of Cd fractions in soil showed a wide difference depending on soil properties. As an average value it was observed that organically bonded Cd amounted 43.7%; residual Cd, 6.5%; and other fractions, 10-15%. 2. With higher soil pH, organically bonded and carbonate Cd fraction tended to be higher but exchangeable fraction lower. Other forms of Cd showed no difference with soil reaction. 3. Organically bonded fraction was positively correlated with soil organic matter content, while others except adsorbed fraction showed an adverse tendency. 4. The relation of fraction distribution to soil C E C was similar to the case of organic matter. 5. Cadmium content in brown rice showed significant possitive correlation with organically bonded Cd content (r = 0.655) and carbonate, Cd content of soil (r = 0.328) but there was no significant correlation with contents of other forms.