• Journal of Preventive Medicine and Public Health
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• v.16 no.1
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• pp.193-198
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• 1983

In the determination of organic solvents in workplaces direct reading tube method have been used in Korea for decades. But this method is less accurate and couldn't measure TWA(Time Weighted Average) for 8 hours. Authors tried to detect Toluene concentration in S factory by using charcoal tube according to NIOSH method. The concentration was 158.8ppm. We propose this charcoal tube method should be substituted to get accurate results and to protect employee in workplaces related with solvents.

• Korean Journal of Metals and Materials
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• v.46 no.12
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• pp.809-816
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• 2008

The influences of various parameters such as inclusions, surface roughness, exposed areas and chloride ion concentrations on the initiation of pitting of Fe-17Cr alloy were investigated, using micro-droplet cell technique. Micro-droplet cell allows one to align the micro-electrode to the desired spot of the working electrode and measure directly local currents with the potentiodynamic polarization. Micro electrochemical tests were carried out at the inclusions after EDX analysis of inclusion. EDX analysis identified inclusions as Cr-oxides. It was found that some active inclusions among Cr-oxide inclusions acted as initiation sites for pitting corrosion. In addition, the rougher surface and the denser chloride ion concentration offered easier pit initiation sites, causing the more susceptible to pitting corrosion.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.141-146
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• 2011

Loess, a natural clay, was evaluated as an adsorbent for the decolorization of Acid Orange II, an azo and reactive dye, from aqueous solution. Adsorption studies were performed at $30^{\circ}C$ and the effect of reaction time, loess dosage, initial concentration, loess particle size, pH, agitation rate were investigated to determine the optimum operation conditions. The removal efficiencies of color were measured to evaluate the effectiveness of loess. From this study, it was found that optimal reaction time was 10 min. Color removal efficiencies of Acid Orange II were increased as higher loess dosage, initial concentration and agitation rate. However, color removal efficiencies decreased when pH is high and loess particle becomes large. Adsorption of Acid Orange II fitted to the pseudo-second-order rate kinetics more than first-order rate kinetics. Langmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of Acid Orange II onto loess fitted to the Freundlich model more than Langmuir model.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.30-37
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• 2022

Because fine dust (PM10) has a close effect on the environment, fine dust generated in the climate and living environment has a bad effect on the human body. In this study, the LSTM model was applied to predict and analyze the effect of fine dust on Gwangju Metropolitan City in Korea. This paper uses prediction values of input variables selected through correlation analysis to confirm fine dust prediction performance. In this paper, data from the Gwangju Metropolitan City area were collected to measure fine dust. The collection period is one year's worth of data was used from january to December of 2021, and the test data was conducted using three-month data from January to March of 2022. As a result of this study, in the as a result of predicting fine dust (PH10) and ultrafine dust (PH2.5) using the LSTM model, the RMSE was 4.61 and the test result value was as low as 4.37. This reason is judged to be the result of the contents of the one-year sample.

• Analytical Science and Technology
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• v.21 no.5
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• pp.438-441
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• 2008

We have developed an alternative to the internal chemical reference based on a calibrated reference signal which is not a real NMR line but an electronically produced signal (HERETIC) and determined the phosphorus concentration using this method. The area ratio of HERETIC and sample peaks obtained from the standard samples was used to measure the concentrations of different samples directly. The analysis of phosphorus by this method showed the excellent linear regression coefficient ($R^2=0.9999$) for the concentration range from 20 ppm to 500 ppm with HERETIC peak as reference.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.88-92
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• 2006

This study is intended to check the flame temperature to raise in burning grade C heavy fuel oil and emulsion fuel oil in a boiler and to measure the concentration of Dry Shoot(DS) and Soluble Organic Fraction(SOF) after collecting the Particulate Matters (PM). The flames temperature in boiler was measured by burning grade C heavy oil and oil-water emulsion (C heavy oil $70\%\;and\;30\%$ of water) Combustion characteristics of two fuels was also compared by trapping particulate matters (PM) in exhaust gas and measuring the generated quantities of DS and SOF in fuel gas.

• 수도
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• s.44
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• pp.6-12
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• 1988

This study was performed to measure the elimination effects of chlorine dioxide on phenol compounds, trihalomethanes (THMs) and algae in drinking water supply. The raw and chlorinated water were treated with 0.5ppm of chlorine dioxide. The phenols contained 0.052mg/1, 0.019mg/1 of raw and treatedwater was absolutely destroyed. The THMs was reduced to 50-60% of the concentration and the algae was inhibited to about 50% of the growth.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1041-1044
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• 2001

This study was performed to evaluate the effect of non-uniform corrosion distribution on the analysis of concrete cover failure. A series of experiments have been undertaken to measure the corrosion rate of reinforcement according to the concentration of chloride ion so as to suggest a relationship between the reinforcement corrosion rate and chloride ion density. The corrosion induced pressure depending on the density of chloride ion has been derived. And nonlinear analysis assuming nonlinear corrosion distribution for cover cracking was achieved and compared with other experimental results to verify the accuracy of the model. Analysis was also performed for various parameters to compare their effects.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.274-276
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• 2006

This study was researched by measuring the amount how much a welder inhaled the major harmful metals such as Fe, Mn, Cu, Zn and so on which occurred at the welding site during welding work and also by measuring the heavy metal concentration in a welder's blood after the welding. By using the mobile fan, the measure of welding fume and the result were taken.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.660-682
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• 2007

An SOFC consists of all ceramic complex oxides each with different electrochemical-property requirements. These requirements, in principle, can be made met to a great extent by controlling or tailoring the defect structure of the oxide. This paper reviews the defect structure, nonstoichiometry as a measure of the total defect concentration, and the defect relaxation kinetics of complex oxides that are currently involved in a variety of growing applications today.