• Analytical Science and Technology
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• v.20 no.1
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• pp.33-40
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• 2007

This study centered on the quantitative analysis of about 27 trace elements including toxic ones using instrumental neutron activation analysis of fine ambient particulate matter in the third and fourth industrial complex area of Daejeon city, Korea. For analytical quality control, the certified reference material (NIST, the National Institute of Standards and Technology, U.S.A., SRM 2783, air particulate on filter media) was used. The errors relative to SRM values of Sb, Mn, V, Mg, Na, K, Ti, Co, Zn, and Sm fell below 5%, while those of Cr, Fe, Ba, Th, Ce, Al, and Cu were less than 10%. From the results of the quantitative analysis, the concentration of toxic metals such as As, Mn, Se, V, and Zn were $3.26{\pm}2.72$, $9.86{\pm}4.71$, $2.18{\pm}1.25$, $4.91{\pm}2.41$, $158{\pm}78ng/m^3$, respectively. And the results of factor analysis indicated that there are no more than six factors of sources of fine ambient particulate with statistical significance in the study area.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.725-731
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• 2010

This study was to evaluate the ozone oxidation of dissolved Fe, Mn, $SO{_4}^{2-}$ ions and color in abandoned mining drainage by conducting a bench-scale operation at various reaction times in an ozone reactor. The influent was collected from an abandoned mine drainage (AMD) near the J Mine in Jungsungun, Kangwon Province. The ozone reactor was operated at ozone reaction times of 10, 20 and 30 min with ozone doses of 0.0 and $2.4g\;O_3/hr$. Samples from each effluent from subsequent sand filtration were regularly collected and analyzed for pH, Fe, Mn, Al, Cr, Hg, $SO{_4}^{2-}$, alkalinity, color, ORP, TDS and EC. The effluent concentrations of Fe and Mn from the sand filter were less than 0.1 mg/L, which were below the concentrations on Korean drinking water quality standards (Fe, Mn < 0.30 mg/L). The influent $SO{_4}^{2-}$, concentrations were not noticeably changed during this ozone oxidation. Cr and Hg in the raw wastewater from the abandoned mining drainage were not detected in this study. The experimental result shows that the ozone oxidation of dissolved heavy metals and subsequent sand filtration of metal precipitates are desirable alternative for removing heavy metals in AMD.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1652-1655
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• 2008

A new high contrast LCD structure for TN mode TFT-LCD, of which the contrast ratio is 1.2 times hi gher than that of the conventional one, has been developed. The contrast ratio of TFT-LCD display can be improved by some modified materials, which like as polarizer, liquid crystal, color filter and light enhancement film. In order to know which condition can get the major contribution for the upgrade of the contrast ratio, we used Taguchi method and analyzed the contribution ratio for each composition and succeed to build up the formula of contrast ratio. From this study, we could achieve the highest CR value as 1200:1 of TN mod e TFT-LCD nowadays.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.997-998
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• 2008

In this paper, we proposed a reduced memory overdrive architecture. Proposed overdrive architecture consists of 2D-DWT filter, BLI and Color Conversion block. For Frame Memory reduction we eliminated HH data in DWT-IDWT process and converted color space RGB into YCbCr. Consequently, we reduced Frame Memory about 50%.

• Smart Media Journal
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• v.2 no.4
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• pp.9-19
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• 2013

This paper gives a review on three illumination issues of face tracking on smart phones: dark scenes, sudden lighting change and backlit effect. First, we propose a fast and robust face tracking method utilizing continuous adaptive mean shift algorithm (CAMSHIFT) and CbCr skin locus. Initially, the skin locus obtained from training video data. After that, a modified CAMSHIFT version based on the skin locus is accordingly provided. Second, we suggest an enhancement method to increase the chance of detecting faces, an important initialization step for face tracking, under dark illumination. The proposed method works comparably with traditional CAMSHIFT or particle filter, and outperforms these methods when dealing with our public video data with the three illumination issues mentioned above.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.249-264
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• 1996

This study was conducted for the purpose of obtaining the fundamental data on improvement of working environment and contributing to health improvement of workers who dealed with metal by assessing the metal concentration in air of industries located in Chang-Won Industrial Complex. Authors measured the concentration of metals(Al, Cd, Cr, Cu, Mn, Ni, Pb, Sn and Zn) is the air to 25 working processes of 73 industries by flame atomic absorption spectrometry from February to December 1994. Personal air sampler was used for air sampling with mixed cellulose-ester membrane filter. The results were as follows : 1. The geometric means(range) of metal concentration; 1) Al: $0.1505mg/m^3$ ($0.0147-18.6100mg/m^3$) 2) Cd: $0.0077mg/m^3$ ($0.0003-7.0710mg/m^3$) 3) Cr: $0.0163mg/m^3$ ($0.0013-1.1510mg/m^3$) 4) Cu: $0.0097mg/m^3$ ($0.0009-0.4950mg/m^3$) 5) Mn: $0.0412mg/m^3$ ($0.0006-4.7877mg/m^3$) 6) Ni: $0.0088mg/m^3$ ($0.0001-1.0170mg/m^3$) 7) Pb: $0.0152mg/m^3$ ($0.0015-0.4499mg/m^3$) 8) Sn: $0.0486mg/m^3$ ($0.0037-0.1500mg/m^3$) 9) Zn: $0.1911mg/m^3$ ($0.0122-8.2920mg/m^3$) 2. The geometric mean of lead exceeded TWA in assembling process of other general purpose machinery not elsewhere classified products manufacturing industries.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.2
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• pp.269-280
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• 2018

This paper reports the results of field evaluation to determine the levels of heavy metals in major industrial complexes in Korea over a seven year period (2007~2013). The measurement of heavy metal was conducted using quartz fiber filter sampling and ICP-AES analysis. In order to validate the analytical performance of these methods, studies were also carried out to investigate data quality control(QC) parameters, such as the method detection limit (MDL), repeatability, and recovery efficiencies. The average concentrations of total suspended particulates (TSP) for the nine industrial complexes in Korea were $104{\sim}169{\mu}g/m^3$, which was higher than other industrial complexes and urban areas. The Sihwa and Banwol industrial complexes were shown to be the biggest contributing sources to high TSP emission ($159{\mu}g/m^3$ and $169{\mu}g/m^3$, respectively). The concentrations of heavy metals in TSP were higher in the order of Fe>Cu>Zn, Pb, Mn>Cr, Ni, As and Cd. It was observed that Fe was the highest in the Gwangyang and Pohang steel industrial complexes. The concentrations of Zn and Pb were high in Onsan, Sihwa and Banwol industrial complexes, and this was attributed to the emission from the nonferrous industry. Additionally, Cr and Ni concentrations were high in the Sihwa and Banwol industrial complexes due to plating industry. On the other hand, Ulsan and Onsan industrial complexes showed high Cr and Ni concentrations as a response to the emission of metal industry related to automobile. The correlation analysis revealed the high correlation between Cr and Ni in plating industry from Sihwa and Banwol industrial complexes. Adding to this, components related to coal combustion and road dust showed high correlation in Pohang and Gwangyang industrial complexes. Then Onsan and Ulsan industrial complexes showed high correlation among components related to the nonferrous metals.

• Journal of Powder Materials
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• v.18 no.2
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• pp.112-121
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• 2011

This study investigated the effect of solvent on the fabrication of Ni-free Fe-based alloy nano powders by employing the PWE (pulsed wire evaporation) in liquid and compared the alloy particles fabricated by three different methods (PWE in liquid, PWE in Ar, plasma arc discharge), for high temperature oxidation-resistant metallic porous body for high temperature soot filter system. Three different solvents (ethanol, acetone, distilled water) of liquid were adapted in PWE in liquid process, while X-ray diffraction (XRD), field emission scanning microscope (FE-SEM), and transmission electron microscope (TEM) were used to investigate the characteristics of the Fe-Cr-Al nano powders. The alloy powder synthesized by PWE in ethanol has good particle size and no surface oxidation compared to that of distilled water. Since the Fe-based alloy powders, which were fabricated by PWE in Ar and PAD process, showed surface oxidation by TEM analysis, the PWE in ethanol is the best way to fabricate Fe-based alloy nano powder.

• Journal of Powder Materials
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• v.18 no.2
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• pp.105-111
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• 2011

This study investigated the effect of wire diameter and applied voltage on the fabrication of Ni-free Fe-based alloy nano powders by employing the PWE (pulsed wire evaporation) in liquid, for high temperature oxidation-resistant metallic porous body for high temperature particulate matter (or soot) filter system. Three different diameter (0.1, 0.2, and 0.3 mm) of alloy wire and various applied voltages from 0.5 to 3.0 kV were main variables in PWE process, while X-ray diffraction (XRD), field emission scanning microscope (FE-SEM), and transmission electron microscope (TEM) were used to investigate the characteristics of the Fe-Cr-Al nano powders. It was controlled the number of explosion events, since evaporated and condensed nano-particles were coalesced to micron-sized secondary particles, when exceeded to the specific number of explosion events, which were not suitable for metallic porous body preparation. As the diameter of alloy wire increased, the voltage for electrical explosion increased and the size of primary particle decreased.

• Journal of Environmental Science International
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• v.30 no.12
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• pp.1081-1092
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• 2021

In this study, the effect on the stability of Aerobic Granular Sludge (AGS) caused by an AGS separator was investigated. The AGS separator was a hydrocyclone. The main factors of the AGS separator were filter pore size (0.125~0.600 mm), conical-to-cylindrical ratio (1.5~3.0), and operating time (1~20 min). The AGS/mixed liquor suspended solid (MLSS) ratio gradually increased to 0.500 mm (AGS/MLSS: 84.3±3.0%). AGS was best separated at the conical-to-cylindrical ratio of 2.5 (AGS/MLSS: 84.7±3.3%). As the operating time increased, the AGS separation performance also tended to increase. The shortest AGS separator run time, but the highest AGS separation performance was 10 min (87.0±2.5%). AGS stability was evaluated by operating the selected AGS separator and sequencing batch reactor. The average removal efficiencies of TOC, TCOD_Cr, SS, TN, and TP were 95.7%, 96.9%, 93.0%, 89.0%, and 96.2%, respectively, which met the effluent standards in Korea. In addition, the AGS/MLSS ratio tended to remain constant, and the sludge volume index demonstrated a tendency to decrease from 140 mL/g to 70 mL/g. During the operation, the particles of AGS in optical microscope observations gradually increased.