• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.110-114
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• 2000

Determination of mercury(II) using Nafion-EDTA-modified glassy carbon electrodes is proposed. it is based on the chemical reactivity of an immobilized modifier, Nafion-EDTA. Differential pulse voltammetry is employed, and the oxidation of complexes, at +0.43V vs. Ag/AgCl, is observed. For a 5-min preconcentration period, a linear calibration curve is obtained for mercury(II) concentrations ranging from 1.0$\times$ 10$^{-8}$ to 1.0$\times$10$^{-6}$ M. Further, when an approximate amount of copper(II) is added to the test solution, We demonstrate that at a preconcentration time of 5 min the Nafion-EDTA-modified glassy carbon electrode has a dynamic range of 2 orders of magnitude(from 10$^{-10}$ to 10$^{-8}$ M) and the detection limit is as low as 0.5$\times$ 10$^{-10}$ M(0.01 ppb). This method is applied to the determination of mercury(II) in sea water(4.0$\times$10$^{-10}$ M, 0.08ppb). The result agrees satisfactorily with the value(below 0.1 ppb) measured by using ICP/MS.

• YAKHAK HOEJI
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• v.5 no.1
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• pp.20-23
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• 1960

The study of the isolative determination of the mixed weak bases of INAH and NA-Pas potentimetrically considering the properties of solvents for the INAH and Na-PAS, dielectric constant and solvative properties of solvents are described. The methanol: dioxan (4:1) and glacial acetic acid: dioxan (4:1) are studied first as the mixed solvent, using the N/10 perchloric acid and glacial acetic acid solution as the titrant. The authors found that there is no inflection on INAH with the methanol: dioxan solvent system and on Na-PAS at glacial acetic acid dioxan solvent system. By applying methanol glacial acetic acid dioxan (1:1:1) solvent system, Na-PAS and INAH were successfully determined isolatively from the mixed sample, showing the distinguished inflections respectively as shown in the titration curves in figures 3 and 4. It is found that this method could save considerable time for the isolative determination of the mixed sample of week bases as Na PAS and INHA which were quite difficult to be determined by the present routine at control laboratory.

• 재활복지
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• v.17 no.4
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• pp.221-244
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• 2013

This study made an exploratory verification targeting severely-disabled persons on how self-determination right and empowerment of the factors organizing independent living affect community relation and productivity of the disabled. For the foregoing, this study collected data for about 2months from May through July 2012 targeting the disabled using Center for Independent Living and the Center for Human Right of the Disabled. As a result of research, this study revealed First, the level of self-determination right of the disabled differed meaningfully depending on the variables such as age, academic ability, existence of spouse, receiving pension, monthly income, residential type, time of occurrence of disability and disability rating, and in the level of empowerment, it showed a meaningful difference according to the factors like academic ability and disability rating. Second, the level of formation of community relation differed meaningfully according to the variables such as age, academic ability, existence of spouse, residential type, time of occurrence of disability, disability rating etc., and the level of productivity showed a meaningful difference according to the variables such as academic ability, existence of spouse, receiving pension, monthly income, multiple disabilities, disability rating etc. Third, as a result of investigation on the effect of self-determination right and empowerment of the disabled on their community relation, both self-determination right and empowerment turned out to have a meaningful and positive (+) effect on the community relation of the disabled. Fourth, as a result of investigation on the effect of self-determination right and empowerment of the disabled on their productivity, this study found that only the variable of empowerment exercises a meaningful and positive (+) influence on the productivity of the disabled. Therefore, self-determination right and empowerment are considered an important variable for enabling them to enjoy independent living in the future by strengthening community relation and productivity of the disabled. For this, it is required to fulfill social welfare and recognize the significance of self-determination right and empowerment in the process of rehabilitation, and develop as well as revitalize a variety of programs related to the above.

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.26-32
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.425-426
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• 2008

• 한국도로학회:학술대회논문집
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• 2011.03a
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• pp.175-181
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• 2011

• 전기의세계
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• v.30 no.12
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• pp.832-837
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• 1981

The study of PLL System to control the Speed of three phase induction motor is described. By solving some problems of conventional PLL system, the system has ability to be easily locked under any conditions. In order to study response velocity and stability of system, this paper presents different filter types and methods of determination of time constant.

• Journal of The Korean Astronomical Society
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• v.8 no.1
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• pp.15-23
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• 1975

A new technique of photographic observations is developed for the determination of time of minimum light of eclipsing binary. An instrumental system to accomplish the observation is described. With this instrument the atmospheric extinction coefficients in Seoul are observed, and four times of minimum light for Algol and W UMa are determined.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.312-312
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• 1998

• Journal of the Korean Statistical Society
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• v.5 no.1
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• pp.19-28
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• 1976

In empirical study for fitting a multiple linear regression model for successive cross-sections data observed on the same set of independent variables over several time periods, one often faces the problem of poor $R^2$, the multiple coefficient of determination, which provides a standard measure of how good a specified regression line fits the sample data.