• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.49-52
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• 2003

Two types of ozone monitors using UV absorption method were tried in consideration of cost of the monitor and precision in measuring. The high concentration ozone monitor for high concentration real time ozone monitoring from ozone generator was composed of a low pressure mercury lamp as UV source, a photo multiplier tube as UV detector and signal processing unit for the most part. This structure could be very useful for low price high concentration ozone monitor due to simple system structure and fairly good monitoring characteristics. The developed system showed good linear output characteristics to ozone in the measuring concentration range of 0.05 and 2 wt.%. For accuracy ambient ozone monitoring in ambient in ppm level, the system composed of a high power pulsed xenon lamp as UV source, an optical spectrometer with a high sensitivity linear CCD array as UV detector and signal processing unit in brief speaking was proposed our study for the first time in the world. The developed system showed good linearity and sensitivity in relative low measuring range between 10ppm and 10,000ppm, and showed some feasibility of high resolution ozone monitor using CCD array as photodetector.

• Journal of Environmental Impact Assessment
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• v.23 no.3
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• pp.220-226
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• 2014

This study investigated temporal-spatial and variations in Geostationary Ocean Color Imager (GOCI) products of parameters total suspended solids (TSS) and chlorophyll-a in the North Marine Areas of East China Sea.GOCI data were collected daily from February 2012 to December 2012. The higher chlorophyll-a values were observed during the investigation period. The relatively large increase in TSS and chlorophyll-a at the sampling stations coupled with typhoon events during the summer rainy period. The abnormal chlorophyll-a concentration was mainly driven by meteorological factors such as typhoon and rainfall in the coastal areas of Jeju and the North Marine Areas of East China Sea. The abnormal high chlorophyll-a concentration at the majority of the coastal stations indicate eutrophication of coastal waters, especially Red tide. The events such as eutrophication and abnormal high chlorophyll-a concentration may potentially influence outbreak of Red Tide, detected with GOCI parameters.

• Journal of Environmental Science International
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• v.11 no.6
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• pp.577-582
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• 2002

Selective catalytic reduction and selective non-catalytic reduction processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. Especially, the selective non-catalytic reduction process can be operated more economical and designed more simply than the selective catalytic reduction. For this reason, many researchers carried out to increase the removal efficiency of nitrogen oxidants in the condition of low oxygen concentration by using the selective non-catalytic reduction process. However, this study was flue gas contained high oxygen concentration of 20(v/v%) with ammonia as a reducing agent. Moreover, it carried out experiment with many factors that are reaction temperature, retention time, initial NO concentration, NSR(normalized stoichiometric ratio). It was determined optimal operating conditions to improve NO removal efficiency with SNCR process. The De-NOx efficiency was increased with NSR, initial NO concentration and retention time increasement. This study has NO removal efficiency over 80% in the high oxygen concentration as well as low oxygen concentration. The injection of reducing agent may be considered for SNCR process and facility operation in 850$\^{C}$ of optimal condition.

• Journal of Animal Environmental Science
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• v.4 no.2
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• pp.149-160
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• 1998

Hog manure slurry amended with sawdust was composted in pilot-scale reactor vessels using continuous aeration nuder different C/N ratios and pH conditions during composting high rate (decomposition) process. For each material two replicated piles were built and monitored over a period of three weeks. The compost piles had an initial volume of 0.18 ㎥. In this study we evaluated the temperature in compost O2 and CO2 evolution, aeration rate, NH3 concentration etc. and investigated the stability of compost during composting high rate process. According to measured results, while the maximum NH3 concentration during composting high rate process. According to measured results, while the maximum NH3 concentration during composting high rate was in the range of 213 to 412 ppm on 5th day which was near the optimum C/N(22∼24) and pH(7.5∼7.9). And then, the NH3 concentration reduced to between 22∼26 ppm by 13th day. The maximum NH3 concentration for the lower C/N(18∼19) and pH value of 6 reached 574∼1,063 ppm by the 16th through 11th days and the NH3 concentration during continuous aerated composting high rate process, it was more important to manage NH3 gas so that compost odor is reduced.

• Journal of Plant Biology
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• v.7 no.1
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• pp.5-10
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• 1964

The effects of briquette ashes on the growth of vegetable (cabbage, lettuce, spinach and radish) and their fresh weight under the culture of the soil mixed with the briquette ashes, and on the chemical properties of the soil were investigated. The growth rate of these palnts and chemical properteis of the soil has shown some influence due to different concentration of briquette ashes added to the soil. The increase of growth in cabbage and lettuce was remarkably found by the plot treated with 1/50 concentration of briquette ashes. The fresh weight of vegetable plants was increased with high concentration of briquette ashes, but if the concentration of briquette ashes was too high, it was rather depressed. Chemical properties in the soil after cultivation of the plants were more depressed than before cultivation. In contrast the available nitrogen content in the soil after cultivation was more increased than before cultivation of the plants. The reduction of available nitrogen and nitrate nitrogen was associated with the increasing intensity of briquette ashes, but available phosphorus content was increased with high concentration of briquette ashes, though its content was not so high as the results obtained by Han(8). The values of total exchangeable base and pH in the soils treated with briquette ashes were increased with a high degree of the concentration of ashes. The value of pH was not significant, and pH value of lime plots was higher than that of briquette ashes. The average value of the water content did not show any difference, and the difference of the content of organic matter in the soil in which different vegetable grew into the plots reached to the significance of a 5% level.

• Journal of Environmental Science International
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• v.26 no.2
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• pp.147-157
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• 2017

This study investigated the characteristics of variations in carbon dioxide concentration and air temperature with the vertical change of surface in a grassplot. Field observations were carried out at a grassplot in Gyeongnam Science High School, over four days in August and November, 2015. Continuous observation equipment (GMP343, VAISALA) was installed at the LP (0.1 m from the surface) and UP (1.1 m from the surface) points, and the carbon dioxide concentration and air temperature were measured simultaneously at 1-min intervals. To summarize the results of the observation, August had higher than average concentrations of carbon dioxide, while November showed average air temperatures. Moreover, the concentration of carbon dioxide was higher at the UP point, while the air temperature was higher at the LP point. The correlation coefficient of carbon dioxide concentration between the UP and LP points was 0.80 in August across all the four days, while it was higher in November at 0.58-0.95. The results of the regression analysis of carbon dioxide concentration with air temperature changes for both August and November showed a distinct change at the LP point (R2=0.36-0.76), as compared to the UP point (R2=0.1-0.57). Between the UP and LP points, the carbon dioxide concentration and air temperature regression analysis results indicated that an active exchange was taking place between the two points.

• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.576-581
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• 2021

Compared to a low concentration, a high concentration clearly entails limitations in terms of predictive performance owing to differences in its frequency and environment of occurrence. To resolve this problem, in this study, an artificial intelligence neural network algorithm was used to classify low and high concentrations; furthermore, two prediction models trained using the characteristics of the classified concentration types were used for prediction. To this end, we constructed training datasets using weather and air pollutant data collected over a decade in the Cheonan region. We designed a DNN-based classification model to classify low and high concentrations; further, we designed low- and high-concentration prediction models to reflect characteristics by concentration type based on the low and high concentrations classified through the classification model. According to the results of the performance assessment of the prediction model by concentration type, the low- and high-concentration prediction accuracies were 90.38% and 96.37%, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.1
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• pp.57-63
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• 1994

In order to comprehension of the behaviour of PAHs in air which is known as carcinogens and/or mutagens suspended Particulates in ambient air were collected by Anderson air sampler from 1992. 6 to 1993. 5 in Seoul. Ten species of PAHs( Phen, An, Fl, R, Py, BaAn, BaP, Chry, BeP, DiB(a, h)An, I123p) were analyzed to understand monthly variations of PAHs distribution of PAHs concentration according to particle size, and correlation between PAHs and independent charactierstics of PAHs The highest concentration of TSP was 155.58$\mu\textrm{g}$/㎥ in May and the lowest was 60$\mu\textrm{g}$/㎥ in August. Concentration of TSP was more affected by coarse particles in spring, otherwise which was more affected by fine particles in winter. According to results of anaylsis of samples that were collected by Anderson air sampler, concentration of PAHs was more high in winter than that in summer. In almost samples collected by Anderson air sampler, concentration of PAHs was more high in coarse particles than in fine particles, but BaP well known as carcinogenic matter had more high concentration in fine particles(56-97.5%) than that in coarse particles(2.5-46%). Correlation between concentrations of TSP and PAHs was more high in fine Particles than in coarse Particles. Both fine particles and coarse particles have negative correaltion with radiation.

• Membrane and Water Treatment
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• v.9 no.1
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• pp.53-62
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• 2018

In this study, vacuum membrane distillation (VMD) was used to treat high-salinity wastewater (concentration about 17%) discharged by chlor-alkali plant after resin regeneration. The feasibility of VMD for the treatment of real saline wastewater by using Polyvinylidene fluoride (PVDF) microporous plate membrane with a pore diameter of $0.2{\mu}m$ was investigated. The effects of critical operating parameters such as feed temperature, velocity, vacuum degree and concentration on the permeate water flux were analyzed. Numerical simulation was used to predict the flux and the obtained results were in good agreement with the experimental data. The results showed that an increase in the operating conditions could greatly promote the permeate water flux which in turn decreased with an increase in the concentration. When the concentration varied from 17 to 25%, the permeate water flux dropped marginally with time indicating that the concentration was not sensitive to the decrease in permeate water flux. The permeate water flux decreased sharply until zero due to the membrane fouling resistance as the concentration varied from 25 to 26%. However, the conductivity of the produced water was well maintained and the average value was measured to be $4.98{\mu}s/cm$. Furthermore, a salt rejection of more than 99.99% was achieved. Overall, the outcome of this investigation clearly indicates that VMD has the potential for treating high-salinity wastewater.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.450-464
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• 2016

Objectives: This study developed and validated reference materials (RMs) to analyze metal compounds in blood. Methods: We referred to KoNEHS (Korea National Environmental Health Survey) to estimate concentrations of blood metals (cadmium, Cd; lead, Pb; mercury, Hg) and applied analytical methods (inductively coupled plasma - mass spectroscopy, ICP-MS, for Cd and Pb; graphite furnace - atomic absorption spectrometry, GF-AAS, for Cd and Pb; and direct mercury analyzer, DMA, for Hg). Homogeneity and stability tests were carried out. In addition, certified values and uncertainties of RMs were calculated through internal and external experiments. All RMs were developed and assessed in various forms according to element, analytical method, and two types of concentration levels high concentration for occupational exposure and low concentration for environmental exposure. Results: All samples showed acceptable homogeneity, except for low concentration of Cd in the GF-AAS method. Short- and long-term stabilities were satisfied by ANOVA testing. In the inter-laboratory comparison, robust medians were lower than the certified values of all RMs (robust median/reference value; $1.301/1.327{\mu}g/L$ for Cd, ICP-MS, low concentration; $3.152/3.388{\mu}g/L$ for Cd, ICP-MS, high concentration; $1.219/1.301{\mu}g/L$ for Cd, GF-AAS, low concentration; $3.074/3.321{\mu}g/L$ for Cd, GF-AAS, high concentration; $14.473/14.516{\mu}g/L$ for Pb, ICP-MS, low concentration; $50.069/50.114{\mu}g/L$ for Pb, ICP-MS, high concentration; $12.881/14.147{\mu}g/L$ for Pb, GF-AAS, low concentration; $47.015/47.591{\mu}g/L$ for Pb, GF-AAS, high concentration; $4.059/4.218{\mu}g/L$ for Hg, DMA, low concentration; $11.474/11.181{\mu}g/L$ for Hg, DMA, high concentration). Conclusion: This study demonstrates procedures for developing and validating RMs for biomonitoring in the field of the environmental health.