• Journal of the Korean earth science society
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• v.33 no.1
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• pp.1-10
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• 2012

Analysis on high-resolution seismic and core data reveals that the sedimentary strata in Gyeonggi Bay consists of four sedimentary units (Unit I-IV, from top to bottom) formed during the late Quaternary period. Unit I is interpreted as sediments of tidal flat and channel-fill deposits, formed during the Holocene transgression. Unit II is divided into shallow-marine facies unit in offshore area and channelized fluvial to estuarine facies unit in nearshore sand ridge and tidal flat. Unit III is considered as tidal flat deposits with the uppermost severely weathered and oxydized layers. This unit is composed of shallow marine sedimentary successions formed during the MIS-5 highstand. The lowermost Unit IV rests on Mesozoic basement rocks, considered as the shallow marine and shelf deposits formed before the MIS-5 lowstand.

• Clean Technology
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• v.17 no.4
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• pp.370-378
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• 2011

Catalytic activity of $V_2O_5-WO_3/TiO_2$-based SCR catalyst was examined for the oxidation of gas-phase elemental mercury to oxidized mercury. Mercury species was not detected on the commercial SCR catalyst after the oxidation reaction of elemental mercury, regadless of the presence of HCl acting as oxidant and the reaction conditions. This suggests that elemental mercury oxidation by HCl could occur via a Eley-Rideal mechanism with gas phase or weakly-bound mercury on the surface of $V_2O_5-WO_3/TiO_2$ SCR catalyst. The activity for mercury oxidation was significantly increased with the increase of $V_2O_5$ loading, which indicates that $V_2O_5$ is the active site. However, turnover frequency for mercury oxidation was decreased with the increase of $V_2O_5$ loading, indicating the activity for mercury oxidation was strongly dependent on the surface structure of vanadia species. The activity for oxidation of elemental mercury under SCR condition was much less than that under oxidation condition at the same HCl concentration and reaction temperature.

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.692-696
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• 1992

$NH_4^+ form cation exchange resin was used to separate one rare earth element from the rare earth mixture solution using Ln-EDTA eluent. Rare earth mixture solution was passed through the resin bed and eluted with 0.1M La-EDTA solution as an eluent. In here all the rare earth element except lanthanum ion are eluted and lanthanum ion absorbed in resin bed is eluted using 0.1M EDTA solution. If Ce-EDTA solution instead of La-EDTA solution was used as an eluent, all the rare earth element except cerium ion are eluted and cerium ion is eluted with 0.1M EDTA solution. This method can be applied to separate the individual rare earth element from the mixture. The separation mechanism is as follows: Absorption : 3RNH_4 ＋ Ln^{3+} = R_3Ln ＋ 3NH_4^+, La-EDTA elution : R_3Ln ＋ La-Y- = R_3La ＋ Ln-Y-, EDTA elution : R_3La ＋ HY^3- = La_-Y ＋ RH ＋ 2R^-.$

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.342-345
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• 2004

국내에 산재해 있는 휴ㆍ폐광산은 주변의 하천이나 농경지에 지속적인 중금속 오염원을 제공하면서 많은 문제점을 발생시키고 있다. 여러 종류의 중금속으로 오염된 토양에 대하여 안정화 공법의 적용가능성을 알아보기 위한 실험을 실시하였다. 오염토양에 적절한 복토첨가제로 생석회와 석회석을 사용하여 첨가제를 넣지 않은 dh염토양과 중금속 용출율을 비교 ㆍ분석하였다. 이 결과 안정화 첨가제들이 Cd, Pb, Zn등의 중금속 용출을 억제하는데 높은 효율을 보여줌을 확인할 수 있었으며, 첨가제를 넣지 않은 토양과 비교한 결과 약 40배 이상의 용출율 감소를 보였다. 또한 실험 시에 첨가제 각각의 함량을 1%, 2%, 5%로 설정하여 현장 적용시 복토에 첨가할 적절한 양을 산출해 낼 수 있도록 하였다. 첨가제 주입으로 인한 용출율 감소는 하나의 중금속에 국한되는 것이 아니라 여러 원소를 동시에 효과적으로 안정화시킬 수 있는 것으로 나타났다. 본 연구 결과는 오염토양에 토양안정화공법을 적용 시에 중요한 자료로 이용될 수 있을 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.282-287
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• 2017

The purpose of this study was predicted the effects of mixing and diffusion due to the operation of the apparatus before the development of the mixed diffusion device for the decontamination absorbent to minimize the influence of contaminant inflow due to radiation accident. The tracer used for the flow characteristics was $^{68}Ga$, $^{99m}Tc$, which is a radioactive isotope, and 2 inch NaI radiation detector was used to detect it. The impeller of the decontamination mixed diffusion system applied to this study was made into three types and the mixing diffusion effect was compared. As a result of analyzing the flow characteristics of the radio-isotope with decontamination mixed diffusion device, mixing, diffusion and flow pattern were obtained. The radial mixing type impeller was able to diffuse to the water surface by the upflow flow, and the fin structure was adjusted for finding optimal conditions. The model 3 type consists of a fin guiding part and an auxiliary fin so that the diffusion speed is higher than that of other types of impellers. It also showed a short time to reach complete mixing.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.240-245
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• 2001

Suppression of nitrate accumulation in vegetables through foliar application of micronutrients was investigated. Spinach and lettuce were grown in pots under greenhouse condition. Micronutrient solutions containing Cu, Mn, Mo, and Zn were used; chitosan was added into one and the other contained chitosan oligomers. The micronutrient solutions were sprayed on the leaves at 3 and 4 weeks after transplanting of 20-day-old seedlings. Plants were harvested at 5-weeks after transplanting. Yield, contents of chlorophyll, Brix value, micronutrient, and nitrate, and nitrate reductase activity were measured. Fresh weights of lettuce and spinach were significantly increased by the foliar application of micronutrients. Contents of chlorophyll and micronutrients were higher in micronutrient-treated plants, while those of nitrate were reduced by about 10 and 14-23% in lettuce and spinach, respectively. Compared to the control plants, nitrate reductase activity was higher in plants treated with micronutrients. Results of this study indicate the effect of micronutrients on the suppression of nitrate accumulation was relatively small in comparison to the contents of nitrate in leaves of spinach and lettuce. To maximize the effect, nutrient composition in solution, application time, and frequency should be further examined, taking into consideration nitrogen level in soil and other environmental factors including light condition.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.327-333
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• 1993

A method was developed for the determination of trace elements in seawater by precipitate flotation preconcentration and subsequent flame atomic absorption detection. In order to quantitatively coprecipitate trace ions such as Cd(II), CuI(II), Fe(III), Mn(II), Pb(II) and Pd(II), 2.0 ml of 1.0M cerium(III) solution was added to 1.0l of seawater and the pH was adjusted to 9.5 with 5.0 M sodium hydroxide solution while stirring with a magnetic stirrer. The precipitate was floated with the aid of surfactant solution (1.0 ml of 0.3% sodium oleate) by bubbling nitrogen gas through a porous (No. 4) fritted glass disk. The floats was collected in a small Erlenmeyer flask by suction. The washed precipitate was dissolved in 8.0 M nitric acid and marked with deionized water in the volumetric flask of 10.0 ml. The analyte was determined by measuring the atomic absorbances in 100-fold concentrated solution. Above all analytes in Kangnung (East Sea) and Kanghwado (West Sea) sea waters were found to be under the detection limit of this method. The recoveries of over 92% for all analytes spiked into seawater samples showed that this method was applicable to the analysis of real seawater.

• Journal of the Korean Magnetics Society
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• v.3 no.1
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• pp.7-12
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• 1993

The effects of Mn, Cr or Co addItion on the magnetic properties of Fe-Ni Invar alloys were investigated. The composition range of the three additives is up to 5wt%. In the temperature range of room temperature-$250^{\circ}C$, the variation of specific magnetization with the addition of Mn, Cr or Co in the Fe-Ni alloys except for 5wt% Co shows the phenomenon characteristics of the Invar effect, viz., the specific magnetization decreases very abrubtly with the temperature and the dependence of temperature on the specific magnetization is in the mixed form of $T^{3/2}$ and $T^{2}$. In the room temperature, the amount of increase in the specific magnetization, Curie temperature and coercivity is in order of Co > Cr > Mn. In the case of 5wt% Co an anomalous phenomena were observed due to the occurrance of ferromagnetic $\alpha$ phase which reduces the invar effect.

• The Korean Journal of Quaternary Research
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• v.12 no.1
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• pp.63-76
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• 1998

한반도는 산악지형이 우세하기 때문에 늪지나 호수의 발달이 불량하다. 현재 소규모 의 자연늪지는 낙동가 하류지역에 분포하며 동해안을 따라 일부 해안지역에 발달하여 있을 뿐이다. 고산지역에도 소규모의 늪지가 최근에 발견되었는데 그중에서도 무제치늪이 국내의 가장 남동쪽에 위치하고 있다. 정족산 정상부를 향하여 4개의 늪지가 차례대로 발달하여있 는데 이들의 성인은 온도차이에 의한 기계적풍화와 암석 차이에 의한 화학적 풍화적작용의 결과로 해석된다, 이들의 형성시기는 제 2늪의 습원퇴적이 가장 오래되 지층으로서 100~ 105cm 심도에서 탄소동위원소 연대측정으로 5,960$\pm$110yr BP. 의결과를 보이고 있드며 제 1늪의 습원 퇴적은 지표로부터 64~69cm 심도의 토탄층 최하부 부분에서 1,785$\pm$120yr BP. 의 연대측정 결과를 확인하였다.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.434-443
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• 1987

The formation constants of the complexes between Ln-EDTA 1 : 1 complex and IMDA have been investigated by a potentiometric titration method at 20.0${\pm}$0.2 degree C and ${\mu}$ = 0.1 (KNO$_3$). Unusually large stability in Ln(EDTA) mixed ligand complexes was found. Trends in the formation constants vs. atomic number of the lanthanide metals were discussed on the basis of coordination number and ionic radius of the metals.