• YAKHAK HOEJI
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• v.14 no.1_2
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• pp.36-43
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• 1970

Imidazole및 유사화합물과 천이원소간의 착염형성은 생화학적으로도 중요한 문제다. 본 논문은 Cd, Ni, Mn, Co등과 착염형성을 polarograph법으로 구명하였으며 착염형성 상수는 deford및 Hume의 수학적방법을 적용하여 계산하였다. 착염형성에서의 enthalpy 변화, .DELTA.H$^{.deg.}$ , 및 entropy변화, .DELTA.S$^{.deg.}$ 를 25.deg.C와 35.deg.C의 실험에서 얻은 결과로부터 구하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.375-381
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• 2002

Measuring of the dissolved oxygen is widely used for the environmental control of natural waters, sewage waste treatment, medical and biochemical studies, soil husbandry, food and drug process control, and prevention of corrosion in boilers. Especially, a power plants need special management for preventing accidents from corrosion, therefore, it is essential to measure the concentration of dissolved oxygen in real-time. In this paper we present a method of measuring dissolved oxygen very accurately up to pub units. This method, called polarograph method, is based on the measures of the electric current generated by the oxidation process in cathode and de-oxidation process in anode, assuming that the amount of the current is proportional to the density of dissolved oxygen.

• YAKHAK HOEJI
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• v.22 no.4
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• pp.201-206
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• 1978

The analysis of elemental sulfur by polarography has already been reported in the literature. Only a discussion of the more important factors influencing the analysis is here presented. (1) The effects of pH on the reduction of elemental sulfur are pronounced and the use of buffered solutions for the analysis of elemental sulfur is necessary. The authors found that a pH of 4-6 was found to be reproducible polarograms by use of D.C. polarograph. However, in alkali solvents the plateau of elemental sulfur has a pronounced dip if the concentration of sulfur is as much as 30ppm. (2) A.C. polarographic method shows a very high sensitivity in the case of sulfur reduction, so that the very low concentration of sulfur can easily be determined (about 1ppm). (3) The characteristics of sulfur wave can be formulated according to Stackelberg-Hauck-Hans equation. It was found that the curve of the peak potential of elemental sulfur in A.C. polarography versus logarithm of sulfur concentration was obtained to be straight line with the slope of 29.6 millivolts. This result was well agreed with theoretical consideration. (4) It was assumed that this polarographical methods were applicable to micro-analysis of elemental sulfur in crude oil and its petrochemical products, precipitated sulfur, and sulfur ointments with accuracy and rapidity.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.271-277
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• 1985

A polarograph with specially designed cell compartment usable in kinetic study of the mitochondrial respiration of a small sized sample was made, and its performance and experimental conditions were examined. An applied potential (ca-1.2V vs. SCE) which gives rise to the second step reduction of oxygen caused a considerable level of a residual current independent of oxygen, which is temporarily interpreted as the reduction current of the membrane-bound redox material(s) of mitochondria. A potential corresponding to the first slop reduction of oxygen (ca-0.4V vs SCE) did not produce the residual current. Thus, it is suggested that a measurement of oxygen concentration in a sample of mitochondria and submitochondrial particles by using dropping mercury electrode should be done with an applied potential of about -0.4V vs SCE. Consumption of oxygen by mitochondria was observed to follow practically zero order kinetics. Its rate constant exhibited the proportional relationship with the respiratory activity of mitochondria. Usefulness of tile instrument was properly demonstrated in the work on the temperature effect on the respiration of mitochondria isolated from several plant 4issues which were selected on the basis of chilling susceptivity.

• Analytical Science and Technology
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• v.5 no.1
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• pp.17-24
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• 1992

Germanium(IV) was determinated in perchloric acid supporting electrolyte solution containing catechol derivates 3.4-dihydroxy benzoic acid, 3.4-dihydroxy benzaldehyde, adrenaline by hanging mercury electrode(HMDE) of anodic stripping polarography. And then to apply this experimental method for determination of germanium(IV) in natural samples. Germanium(IV) was determinated $300{\mu}g/L$ in ginseng and $210{\mu}g/L$ in mineral water.

• Journal of Environmental Health Sciences
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• v.12 no.2
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• pp.11-15
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• 1986

Hydroxlamine effect on the determination of dissolved oxygen by the azide-modified Winkder method and polarography has been studied. It was found that hydroxylamine interference on the dissolved oxygen by the azide-modified Winklet method can be eliminated completely by using permanganate. An inexpensive and convenient polarograph device was constructed. Dissolved oxygen in an air-saturated 0.1 F KCl solution undergoes, independent of hydroxylamine concentrations a two-step irreversible reduction at the dropping electrode the $H_2O_2$ produced in the first step is reduced to $H_2$O in the second. Two waves of equal size result, the first with a half-wave potential (E1/2) at about -0.13 V and the second at about -0.91 V (vs. SCE).

• YAKHAK HOEJI
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• v.17 no.4
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• pp.217-222
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• 1973

Although a considerable amount of work has ben carried out, on the reduction of p-nitrosalicylic acid with Pb, Ni, Cu and Hg cathodes, published results do not proceeded the synthesis of p-aminosalicylic acid. In order to get the reduction potential and the mechanism of reduction, therefore, the electrode reactions occurring during "polarographic reduction" have been studied more fully. As a result, the author found that p-aminosalicylic acid (PAS) can be only produced in a HCl-ethanol solution using Sn cathode with the current density of 4.0A/$dm^{2}$, at 40-$50^{\circ}$.

• Journal of the Korean Chemical Society
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• v.11 no.4
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• pp.138-142
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• 1967

The electrode reduction velocities of Zn, Ni and Co ions at DME in various supporting electrolytes and temperatures were measured by Randles' method. The values for Zn ions agreed with Randles' values within 20%. As mentioned in the auther's previous paper, the observed values of Ni and Co ions were considered to be reasonable. In the present work the curves log y vs. log z for the various metals in the range of 20~35$^{\circ}C$ were obtained.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.84-87
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• 1961

A polarographic method for rapid determination of Uranium in the presence of foreign ions was proposed. The method is based on the measurement of polarogram in the sulfuric acid as supporting electrolyte. In this medium Uranyl ions give well defined reduction waves, and half-wave potentials are -0.19V vs. S.C.E. as first wave, and uncertain volt. vs. S.C.E. as second wave in $2.4 N-H_2SO_4.$ The first wave has a linear relationship between the concentration of Uranyl ion and wave height. The author also studied a method for rapid determination of Uranium in Korean monazite sand without eliminating the foreign ions. The Korean monazite sands were analyzed by this method and satisfactory result were obtained.

• YAKHAK HOEJI
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• v.16 no.2
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• pp.73-84
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• 1972

단백질과 전이금속 이온들과의 상호작용을 연구하는데 있어서 단백질중의 이미다졸기 및 아미노산의 반응성은 중요하다. Cd(II)-2-메틸이미다졸 착물들의 경우 이미다졸 분자중의 결합측은 "피로올"형 보다 오히려 "피리딘" 질소임을 알 수 있다. 이 착물들의 환원파는 가역적이며 2전자반응으로 나타난다. 그리고 이미다졸 존재하의 Ni(II) 이온은 촉매파를 나타내며 Ni(II) 이온만의 환원파는 불가역성인 것에 비해 가역성을 보여주었다. 또한 그 반파전위는 Ni(II) 이온만의 반파전위보다 수백 mV 양전위로 이동된다. 이러한 성질은 전극 반응에 관여한 주물질이 전극 표면에서 흡착되어 환원되기 때문이다. 이미다졸 농도의 대수값에 대해 반파전위를 도시했을 때 그 기울기가 30mV로써 이론치와 일치한다. 한편 $Cd(II)-2CH_{3}Im$의 단계적 생성항수 $pK_{1},pK_{2},pK_{3},pK_{4}$는 각각 2.68, 4.01, 4.90, 5.36이었다.4.01, 4.90, 5.36이었다.