• Journal of Industrial Technology
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• v.27 no.A
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• pp.19-24
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• 2007

This research was done for possible treatment of impermeable surfaces rainwater runoff containing heavy metal ions by manganese oxide coated on polypropylene support. Manganese oxide was coated by Birnessite Coating Methods(BCM)and the coating analyzed by SEM and FT-IR techniques. The efficiency of heavy metal ions adsorption was also assessed via both batch and column tests. Adsorption efficiencies of Cd, Zn, Cu, and Pb were 99.4%, 98.9%, 96.7%, and over 95.7%, respectively. The adsorption progress pattern reveals quite fast adsorption at initial periods of treatment and change to slower rates at later times.

• Analytical Science and Technology
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• v.17 no.4
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• pp.363-367
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• 2004

A simple and convenient digestion method was developed for the determination of heavy metal in polyurethane sample using only nitric acid in open system without heating. This digestion method had prevented loss of volatile elements of Hg and As and reduced the pretreatment time for the sample digestion. The detection limit is lowered over 10 times than that of microwave digestion method. Recoveries in polyurethane material were 108% for As, 96 ~ 99% for Hg, 102 ~ 103% for Cr, 98 ~ 102% for Pb, 86 ~ 90% for Cd, and 90 ~ 93% for Cu.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.98-105
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• 1999

As the IC(Integrated Circuit) has been densified and complicated, it is required to thorough process control to improve yield. Experts, for this purpose, focused on the process analysis automation, which is came from the strict data management in semiconductor manufacturing. In this paper, we presents the process analysis system that can analyze causes, for a output after processes. Also, the plasma etching process that highly affects yield among semiconductor process is modeled to predict a output before the process. To approach this problem, we use adaptively trained neural networks that exhibit superior accuracy over statistical techniques. And in comparison with methods in other paper, a method that history of trend for input data is considered is shown to offer advantage in both learning and prediction capability. This research regards CD(Critical Dimension) that is considerable in high integrated circuit as output variable of the prediction model.

• Journal of Korea Soil Environment Society
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• v.2 no.3
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• pp.69-80
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• 1997

This investigation was conducted to provide information for characteristics of environmental pollution by the heavy metals from the abandoned gold mine in order to characterize the distribution patterns and environmental damages of the contaminants to the surrounding environment. Through analysis of CN, Cd, Cu, Pb, Zn, As, Cr, and Hg in a mine tailings, paddy soils, and stream sediments, the physico-chemical properties of the mine tailings and paddy soils were measured. The pH's were 5.4, 8.4 for the paddy soil and mine tailing, respectively. The maximum contents of CN, Pb, Cd, and As the in mine tailing were 99.98, 1,752.72, 31.88, and 298.50 mg/kg, respectively. The amounts of these ions were higher than the standard level of industrial area in Korea. The average content of CN and heavy metals in the paddy soils were higher than the background level of heavy metals in the unpolluted paddy soils around the mine. Especially, the contents of heavy metals in the paddy soils along the adjacent stream were higher compared to the paddy soil that was not influenced by the mine tailings. The contents of CN and heavy metals in the stream sediment close to the mine area were similar to those of the mine tailings, but decreased along the distance of the stream farther away from the tailings that was the source of these pollutants.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.75-81
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• 2004

A large amount 2.1×106 ㎥ of the polluted sediment was dredged from the Masan Bay and deposited in Gapo confined area, Masan. The dissolved metal concentrations of seawater in the dumping site (Gapo area) were observed during one tidal cycle and compared with those of seawater obtained from Jinhae Bay. The sediment was evaluated as from Non polluted to Moderately polluted by USEPA standards. It was judged that toxicological effects of sediment analyzed ranged from ERL to ERM with copper and zinc, and ERL with cadmium, chrome, lead, and nickel by the Adverse Biological Effects. The pollutant concentration was low in surface sediment compared to deeper sediment since the sediments with relatively low concentrations of pollutant were dumped to the surface. The pollutant concentration was low in surface sediment compared to deeper sediment since the sediments with relatively low concentrations of pollutant were dumped to the surface. The benthic organisms in Gapo area had higher concentrations of trace metals (Oyster: Zn 238.96, Cu 5.29 ㎍/g wet wt., Clam: Zn 17.71, Cu 1.00 ㎍/g wet wt., Mussel. Zn 187.98, Pb 0.28, Cr 0.15, Mn 4.23, Sr 1.45 and Fe 100.33 ㎍/g wet wt.) compared to outside of dumping site. However, the trace metal level in the bivalves was less than the NFPQIS (National Fisheries Products Quality Inspection Service) standard.

• Macromolecular Research
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• v.17 no.5
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• pp.319-324
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• 2009

A new $\pi$-conjugated polymer, poly[(2-methoxy-(5-(2-(4-oxyphenyl)-5-phenyl-1,3,4-oxadiazole)-hexyloxy))-1,4-pheny1ene-1,2-etheny1ene-alt-(10-hexyl-3,7-phenothiazine )-1,2-ethenylene] (PTOXDPPV), was synthesized by the Heck coupling reaction. The electron transporting unit, conjugated 1,3,4-oxadiazo1e (OXD), is attached on the main chain via linear 1,6-hexamethylenedioxy chain. The band gap and photoluminescence (PL) maximum of PTOXDPPV are 2.35 eV and 565 nm, respectively. These values are very close to those of po1y[(2,5-didecyloxy-1,4-phenylene-1,2-etheny1ene )-alt-(l0-hexyl-3,7-phenothiazine)-1,2-ethenylene] (PTPPV), which does not have OXD pendant. The estimated HOMO energy level of PTOXDPPV was -4.98 eV, which is very close to that of PTPPV (-4.91 eV). The maximum wavelength of EL device based on PTOXDPPV and PTPPV appeared at 587 and 577 nm, respectively. In the PL and EL spectrum, the emission from OXD pendant was not observed. This indicates that the energy transfer from OXD pendants to main chain is occurred completely. The EL device based on PTOXD-PPV (ITO/PEDOT/PTOXDPPV/AI) has an efficiency of 0.033 cd/A, which is significantly higher than the device based on PTPPV (ITO/PEDOT/PTPPV/AI) ($4.28{\times}10^{-3}\;cd/A$). From the results, we confirm that the OXD pendants in PTOXDPPV facilitate hole-electron recombination processes in the emissive layer effectively.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.2
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• pp.106-114
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• 2017

There is an increasing concern over heavy metal(loid) contamination of soil in agricultural areas including paddy soils. This study was conducted to determine the bioconcentration factor (BCF) for heavy metal(loid)s to brown rice grown in paddy soils vulnerable to heavy metal(loid)s contamination, for the quantitative health risk assessment to the residents living nearby the metal contaminated regions. The samples were collected from 98 sites nationwide in the year 2015. The mean and range BCF values of As, Cd, Cu, Ni, Pb, and Zn in brown rice were 0.027 (0.001 ~ 0.224), 0.143 (0.001 ~ 2.434), 0.165 (0.039 ~ 0.819), 0.028 (0.005 ~ 0.187), 0.006 (0.001 ~ 0.048), and 0.355 (0.113 ~ 1.263), respectively, with Zn showing the highest. Even though the relationship between heavy metal(loid) contents in the vulnerable soils and metal contents in brown rice collected at the same fields was not significantly correlated, the relationship between log contents of heavy metal(loid)s in the vulnerable soils and BCF of brown rice wes significantly correlated with As, Cd, Cu, and Zn in rice. In conclusion, soil environmental risk assessment for crop uptake should consider the bioconcentration factor calculated using both the initial and vulnerable heavy metal(loid) contents in the required soil and the crop cultivated in the same fields.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.681-687
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• 2015

We investigated the effects of feeding rate on the growth performance of growing and sub-adult olive flounder Paralichthys olivaceus, and the optimum feeding rate at high water temperature (25-31℃). In experiment I, two replicated groups of fish (113 g) were fed a commercial diet (CD) at rates of 0, 0.7, 1.2, 1.7, 2.2, and 2.4% (satiation) body weight (BW) per day for 4 weeks. In experiment II, two replicated groups of fish (313 g) were fed a CD feeding rates of 0, 0.3, 0.5, 0.7, 0.9, and 1.0% (satiation) BW per day for 4 weeks. In experiment I, the weight gain (WG) and specific growth rate (SGR) of fish fed at 0.7 and 0.9% BW per day was significantly higher than that of unfed fish (0%) and fish fed at 0.3, 0.5, and 1.0% (satiation) BW per day. In experiment II, the WG and SGR increased significantly as feeding rate increased from 0 to 2.2% BW per day, but decreased in the satiation group (2.4%). Broken-line regression analysis of WG showed that the optimum feeding rate of growing and sub-adult olive flounder were 1.98% and 0.55% BW per day, respectively, at the high water temperature.

• Environmental Engineering Research
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• v.14 no.4
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• pp.212-219
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• 2009

Emission characteristics of air pollutants from three commercially operating cement kilns co-burning waste were investigated. The major heavy metals emitted were mercury (Hg), zinc (Zn), nickel (Ni), chromium (Cr), lead (Pb), cadmium (Cd), and arsenic (As) Removal efficiency of the bag filter was above 98.5% for heavy metals (except Hg), and above 60% for Hg. Higher fractions of heavy metals entering the bag filter were speciated to cement kiln dust. On average, 3.3% of the -heavy metals of medium and low toxicity (Pb, Ni, and Cr) entering the bag filter were released into the atmosphere. Among highly toxic heavy metals, 0.14% of Cd, 0.01% of As, and 40% of Hg entering the bag filter were released into the atmosphere. In passing through the bag filter, the proportion of oxidized Hg in all cases increased. Emission variations of hazardous air pollutants in cement kilns tested were related to raw materials, fuel, waste feed and operating conditions. Volatile organic compounds detected in gas emissions were toluene, acrylonitrile benzene, styrene, 1,3-butadiene, and methylene chloride. Although hazardous air pollutants in emissions from cement kilns co-burning waste were within the existing emission limit, efforts are required to minimize their levels.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.277-284
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• 2012

This study developed a new ceramics in which natural zeolite was mixed and calcined with industrial by-product such as converter slag, red mud, and fly ash and evaluated the feasibility of the ceramics for removal of heavy metals in acid wastewater. The removal rate of heavy metal by ceramics increased in the order of ZS (zeolite and slag) > ZR (zeolite and red mud) > ZF (zeolite and fly ash) ceramics. The alkalinity increment and coherence of ceramics were increased in the order of ZS > ZR > ZF ceramics. The mixing ratio of natural zeolite to industrial by-product for maximum removal efficiency of heavy metal was 1:1 for ZS ceramics and 1:3 for ZR and ZF ceramics. The order of removal efficiency of heavy metal was observed to be ZS > ZR > ZF ceramics under the mixing ratio of 1:1 for ZS ceramics and 1:3 for ZR and ZF ceramics. The removal efficiency of heavy metal by ZS ceramics with 1:1 mixing ratio was Al 100%, Cd 54.6%, Cr 99.9%, Cu 98.7%, Fe 99.9%, Mn 42.2%, Ni 59.9%, Pb 99.8%, Zn 87.6%, respectively. In addition, the removal capacity of heavy metal by ZS ceramics was observed to be Al 2.01 mM/g, Cd 0.27 mM/g, Cr 1.02 mM/g, Cu 0.83 mM/g, Fe 0.95 mM/g, Mn 0.41 mM/g, Ni 0.55 mM/g, Pb 0.25 mM/g, Zn 0.70 mM/g, respectively. The comparative evaluation in the light of removal capacity, alkalinity increment, and coherence of ceramics showed the ZS ceramics had higher feasibility as a media than others for removal of heavy metals in acid wastewater.