• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.693-698
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• 2002

A method has been described for the determination of Cu(Ⅱ), Pb(Ⅱ), Ni(Ⅱ), Cd(Ⅱ), Mn(Ⅱ) and Fe(Ⅲ) by flame atomic absorption spectrometry (FAAS) after preconcentration on Amberlite XAD-16 resin, using hexamethyleneammonium-hexamethylenedithiocarbamate (HMA-HMDTC) as a chelating agent, and NH3/NH4Cl buffer solution (pH 9). Influences of various analytical parameters such as pH, concentration of nitric acid, amount of analytes, diverse ions and sample volume were investigated. The relative standard deviation (RSD) and the detection limit (LOD) were found in the range of 0.8-2.9% and 0.006-0.277 ㎍/mL,respectively. Recoveries obtained by the column method were quantitative ( >95%) at optimum conditions.The method was applied to the determination of some metal ions in seawater and wastewater samples. A high preconcentration factor (about 150 for seawater and 75 for wastewater samples) and simplicity are the main advantages of this suggested method.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.307-312
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• 2001

Adsorption capacities of toxic heavy metal ions using as-received carbon(AC), single and double surface-modified activated carbon(OAC and DSMC) in wide pH ranges are extensively evaluated. Physical and chemical properties of surface-modified activated carbons are evaluated through BET analysis, surface acidity and oxides measurements. Based oil tile adsorption isotherms of Pb, Cd and Cr ions by AC, OAC and DSMC, the adsorption amount on DSMC was obviously higher than that on the other carbons. Breakthrough behaviors of ternary metal ions in a column packed with three kinds of carbon were also characterized with respect to the variations of the influent pH and concentration. The adsorption capacity of DSMC in a fixed bed stood a favorable comparison with that of as-received carbon.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.251-253
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• 2000

본 연구는 대전 1,2 공단 지역을 대상으로 발암 금속 6종(As Be, Cd, Cr, Ni 및 Pb)을 포함한 15종의 독성 금속을 선정하여 유도결합 플라스마 분광법(ICP-MS)을 이용하여 3년간 분석하고 이 농도 자료에 근거하여 각 금속의 확률론적 농도를 평가하고자 한다. 대기중 부유분진은 대전시 대화동(대전 1,2 공단내 대화동 동사무소 건물 옥상)에 high-volume air sampler(Graseby Andersen : SAUB-10H Model, USA)를 약 0.85$\textrm{m}^3$/min으로 운전하여 시료당 공기량이 약 1,200 $\textrm{m}^3$가 유지되도록 포집하였다. (중략)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.463-468
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• 2003

This study observed change of survival rate, activity and foot structure of the equilateral venus (Gomphina veneriformis) exposed to cadmium. Survival rate and activity of the clam exposed to cadmium was reduced with increase of exposure duration and concentration. Change of survival rate and activity was observed in the early exposure time (7 days) in the condition of above 1 77 mg/L and 0.88 mg/L, respectively. Activity reduction of the clam exposed to cadmium seems to be caused by epidermal layer deformation, muscle fiber fragmentation and muscular layer collapse of the foot.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.372-378
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• 2003

This study investigates the fractional composition and the leaching characteristics of heavy metals in polluted soils due to mining activities. The fractionated composition of heavy metals is classified into five fractions, adsorbed, carbonate, reducible, organic and residual fraction. The status of humic substances in mine wastes of most sites are polyhumic except tailing from Sangdong mine. According to the sequential extraction procedures (SEPs), leaching probabilities of Cd in coal wastes and tailing are relatively low due to high percentage of residual fraction. 46.4% of Ni in tailings from Sangdong mine is probably leached under oxidized environment, and 39.4% of Cu in these tailings is readily extracted under strongly oxidized environment by organic fraction. According to leaching condition of pH 3.0 and pH 5.6, the amount of heavy metals leached out of coal wastes and tailing increases to 1/2 hours. At pH 3.0 and pH 5.6, concentration of Ni in tailing increases up three times of the initial value. Heavy metals released from coal wastes and tailing were not influenced significantly by leaching time.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.149-150
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• 2000

Lead-doped calcium sulfide(CaS:Pb) thin film electroluminescent devices were deposited using atomic layer deposition(ALD). CaS:Pb is a very promising blue phosphor showing very high luminance and the color coordinate close to the blue of cathode ray tube. The luminance, $L_{25}$, of CaS:Pb(1.6 mol.%) EL device was higher than 80 $cd/cm^2$ at a driving frequency of 60Hz. The color coordinates of blue EL emission of CaS:Pb deposited by ALD are consistent with the Pb concentration ranging from approximately 0.5 to 3 mol.%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.581-584
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• 2002

A new method for the preparation of lanthanide ions activated strontium aluminates phosphor by combustion method has been proposed. Combustion method consist of the redox reactions between the respective metal nitrates and urea in a preheated funace at $500^{\circ}C$. The luminescence behavior of the phosphor was studied and compared with corresponding phosphor prepared by conventional method. Effect of $Mg^{2+}$ ion concentration in strontium aluminate phosphor was investigated and the maximum luminescence of about $100cd/m^2$ was obtained. This method gave better brightness and small size to the phosphor than made by conventional method.

• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.663-672
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• 2007

The mutual separation behavior of actinides and rare earths in a countercurrent multistage reductive extraction system was predicted by computer calculation. The distribution information for actinides and rare earths in the reductive extraction systems of LiCl-KCl/Cd and LiCl-KCl/Bi was collected from literature and then it was used for the calculation of a multistage extraction. The results of the concentration profiles throughout the extraction cascade, recovery yields of various metal solutes, and separation factors between the actinides and rare earths were calculated. The effects of the major process parameters, such as reducing agent content in the metal phase, number of stages, and salt/metal flow ratio, etc., on the extraction behavior were also examined.

• Bulletin of the Korean Chemical Society
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• v.29 no.7
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• pp.1391-1394
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• 2008

Polymer materials are very difficult to decompose for the purpose of chemical analysis. Nondestructive analysis without pretreatment provides a suitable solution that will overcome this obstacle. In this study, CRM candidate samples that contained toxic elements such as As, Cd, Cr and Zn in a polypropylene (PP) were analyzed using instrumental neutron activation analysis (INAA). The analytical results were obtained from ten samples selected by random sampling at two different concentration levels (low and high). Particular attention was paid to reducing analytical errors and evaluating the associated uncertainty.

• The Korean Journal of Food And Nutrition
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• v.12 no.3
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• pp.246-251
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• 1999

The purposed of this study was to investigate the efficient recycling of food waste according to the restaurants type. To the investigated of characteristic of food wastes in different types of restaurants we were collected the sample of 60 as Korean 35 Chinese 10 Japanese 5 Western 5 Flour 5 in Swoon. The average water content of food waste was 79.9% and Korean restaurant was 80.3% which was hig-her than that of any other serving type. On the examination of a organic matter content of food waste according to the season crude fiber was higher in may and July crude protein content was higher in January and march than that other seasons. The average pH of food waste was 4,74 C/N ratio was 15.8 and the average cation content was K 0.57% Ca 0.39% Mg 0.22% NaCl 3.36% respectively The aver-age concentration of Fe, Zn, Pb, Cu, Cr, Cd Ni were 154.37 mg/kg 24.79 mg/kg 0.27 mg/kg 5.63 mg/kg 5.49 mg/kg, 0.31mg/kg 1.07mg/kg respectively.