• Economic and Environmental Geology
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• v.40 no.2 s.183
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• pp.251-262
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• 2007

The purpose of this research is to develop a Geological Information System(GIS) in order to store, manage and display geochemical data observed from references of recently domestic granite. There is still no use in geochemical and mineralogical information such as REE(rare earth element), trace elements, mode data(modals or mineral composition) and major elements. Therefore, we need to construct the standardized database system for the analytical data of granites through the verification of its data in South Korea. To construct the information system for geochemical and mineralogical information of granites in South Korea. Firstly, we collected the existing research data related digital map data. Secondly, we extract granite polygons to digital geological map and convert the polygon to points in South Korea. Thirdly, we considered both database schema and symbols of REE elements, trace elements, modal data and major mineral. Fourthly, we carried out all sorts of process to build granite database for GIS statistic analysis and visualization.

• Analytical Science and Technology
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• v.27 no.6
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• pp.352-356
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• 2014

Various studies have been done to improve the properties of the steel by adding boron to the steel. Some studies have reported on the analysis of the boron in steel by AAS (atomic absorption spectrometry), ICP-OES(inductively coupled plasma-optical emission spectrometry), ICP-MS (inductively coupled plasma/mass spectrometry). The volatile loss of boron of steel in sample digestion and the separation procedure for avoiding matrix effect by high concentration of iron are difficulties for determination of boron in steel. The method to determine boron in steel by ICP-MS was developed without volatilization of boron in sample digestion step with $HNO_3-NH_4HF_2$ digestion method, and the additional separation process for avoiding matrix effect. Complete decomposition of steel with $HNO_3-NH_4HF_2$ digestion method, and boron determination by ICP-MS in the matrix of high concentration of iron were possible. Quantitative recoveries of boron in certified standard steel by new method in this study were 103 to 111%, and the relative standard deviation is less than 5%. The method detection limit was $1.17{\mu}g/g$.

• Economic and Environmental Geology
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• v.46 no.3
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• pp.221-234
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• 2013

Laboratory experiments for the reaction with supercritical $CO_2$ under the $CO_2$ sequestration condition were performed to investigate the mineralogical and geochemical weathering process of the sandstones and mudstones in the Pohang basin. To simulate the supercritical $CO_2$-rock-groundwater reaction, rock samples used in the experiment were pulverized and the high pressurized cell (200 ml of capacity) was filled with 100 ml of groundwater and 30 g of powdered rock samples. The void space of the high pressurized cell was saturated with the supercritical $CO_2$ and maintained at 100 bar and $50^{\circ}C$ for 60 days. The changes of mineralogical and geochemical properties of rocks were measured by using XRD (X-Ray Diffractometer) and BET (Brunauer-Emmett-Teller). Concentrations of dissolved cations in groundwater were also measured for 60 days of the supercritical $CO_2$-rock-groundwater reaction. Results of XRD analyses indicated that the proportion of plagioclase and K-feldspar in the sandstone decreased and the proportion of illite, pyrite and smectite increased during the reaction. In the case of mudstone, the proportion of illite and kaolinite and cabonate-fluorapatite increased during the reaction. Concentration of $Ca^{2+}$ and $Na^+$ dissolved in groundwater increased during the reaction, suggesting that calcite and feldspars of the sandstone and mudstone would be significantly dissolved when it contacts with supercritical $CO_2$ and groundwater at $CO_2$ sequestration sites in Pohang basin. The average specific surface area of sandstone and mudstone using BET analysis increased from $27.3m^2/g$ and $19.6m^2/g$ to $28.6m^2/g$ and $26.6m^2/g$, respectively, and the average size of micro scale void spaces for the sandstone and mudstone decreased over 60 days reaction, resulting in the increase of micro pore spaces of rocks by the dissolution. Results suggested that the injection of supercritical $CO_2$ in Pohang basin would affect the physical property change of rocks and also $CO_2$ storage capacity in Pohang basin.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.2
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• pp.227-234
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• 2019

A user-friendly modeling interface is developed for a process-based total system performance assessment framework (APro) specialized for a generic geological disposal system for high-level radioactive waste. The APro modeling interface is constructed using MATLAB, and the operator splitting scheme is used to combine COMSOL for simulation of multiphysics and PHREEQC for the calculation of geochemical reactions. As APro limits the modeling domain to the generic disposal system, the degree of freedom of the model is low. In contrast, the user-friendliness of the model is improved. Thermal, hydraulic, mechanical and chemical processes considered in the disposal system are modularized, and users can select one of multiple modules: "Default process" and multi "Alternative process". APro mainly consists of an input data part and calculation execution part. The input data are prepared in a single EXCEL file with a given format, and the calculation part is coded using MATLAB. The final results of the calculation are created as an independent COMSOL file for further analysis.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.705-707
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• 2005

For the development of geothermal energy, many different kind of geoscientific data including both surface geological data and underground geomechanical data, are acquired. Integration of such data itself for better understanding of underground condition is not a simple process due to complexity of the data, i.e. mixture of 20 and 3D data, mixture of geological data, geochemical data, geomechanical data and hydrogeological data. This paper reports a preliminary suggestion of GIS modeling for such specific purpose. Data used for GIS modeling mainly came from British case studies. The modeling is much more focused on the design of database for 3D underground geotechnical data in this study.

• Economic and Environmental Geology
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• v.21 no.2
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• pp.139-148
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• 1988

The altered volcanic rocks, ranging from tuffaceous to andesitic rocks are widely distributed around the "caldera" area in the southeastern part of Kyeongsang province. The volcanic activity and tectonic movement are assumed to be followed by the hydrothermal activities in the area. From the mineral assemblage the type of alteration can be divided into two types; propylitic and argillic. The average concentration of gold in hydrothermally altered rocks is somewhat lower (about 20 ppb) than that of fresh rocks (45-25 ppb), but for Ag, vice versa. During the hydrothermal process, the concentration of the trace elements Ag, Hg, Co, As, Hf, Sc, Si, Al increased, and that of Na, Rb, K, Au, Mg, Ca etc. decreased. The high anomalous contents of silver for altered rocks range from 4-7 ppm and 1-3 ppm for relatively fresh rocks.

• Journal of the Korean earth science society
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• v.42 no.5
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• pp.556-570
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• 2021

This study presents the data analysis results of groundwater chemistry and the occurrence of fluoride in groundwater obtained from the groundwater quality monitoring network of Korea. The groundwater data were collected from the National Groundwater Information Center and censored for erratic values and charge balance (±10%). From the geochemical graphs and various ionic ratios, it was observed that the Ca-HCO₃ type was predominant in Korean groundwater. In addition, water-rock interaction was identified as a key chemical process controlling groundwater chemistry, while precipitation and evaporation were found to be less important. According to a non-parametric trend test, at p=0.05, the concentration of fluoride in groundwater did not increase significantly and only 4.3% of the total groundwater exceeded the Korean drinking water standard of 1.5 mg/L. However, student t-tests revealed that the fluoride concentrations were closely associated with the lithologies of tuff, granite porphyry, and metamorphic rocks showing distinctively high levels. This study enhances our understanding of groundwater chemical composition and major controlling factors of fluoride occurrence and distribution in Korean groundwater.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.4
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• pp.351-359
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• 1995

In order to investigate geochemical behaviors of artificial radionuclide($^{137}$ Cs), the fallout deposition of arificial radioisotope($^{137}$ Cs) was measured from May to October in 1994 at the Korea Ocean Research & Development Institute(KORDI), Ansan, Kyunggido, Korea. And to study radioisotopic behavior and cumulative action in soil, soil samples were collected from Kwang-Leung Forest, Kyunggidom and artificial radioisotope ($^{137}$ Cs) and natural radioisotope($^{210}$ Pb) were identified. The amount of $^{137}$ Cs in atmosphere collected by wet deposition process in May was found to be 4.95 to 11.96mBq m$^{-2}$ whereas the amounts of $^{137}$ Cs by dry deposition process in May and October were found to be 4.0mBq g$^{-1}$ and 3.0mBq g$^{-1}$ , respectively. The amount of $^{137}$ Cs accumulated in soil was measured to be 311mBq cm$^{-2}$ , which contained 83% of the total inputs from atmospheric fallout (374 mBq cm$^{-2}$ ) since 1960s. In addition, the accumulation rate and the annual flux of $^{210}$ Pb into soils were 0.32cm yr$^{-1}$ and 34 mBq cm$^{-2}$ yr$^{-1}$ , respectively. Conclusively, it was found that arificial radioisotopes were mainly from the stratosphere and soil resupension of continental China through the troposphere.

• Economic and Environmental Geology
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• v.7 no.4
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• pp.175-184
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• 1974

Weathering of granites has a great geochemical significance, because of their chemical stability near the earth surface which is more pronounced than in most other rocks. The author intended to observe the relative mobility of major elements in weathering process of the granite, distributed on outskirts of Iri city Jeolla-bugdo, Korea. He analysed fresh granites and weathered ones from the Baeg-Gu granite mass and obtained following conclusions in the triangle-diagrams and the oxidized variation diagrams of the samples. 1) The increasing phenomena of $H_2O$ was observed clearly in early and late stages of weathering process. 2) The early stage of weathering is commenced by physical weathering and followed by chemical weathering. 3) The ratio of $FeO/Fe_2O_3$, FeO/MgO, and $SiO_2/Al_2O_3$ decreased uniformly from early to late stage of weathering processes. 4) It was proved that weathering potential of granite was larger than that of basaltic rock. 5) The order of mobility in major elements was Ca, Na and K

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.1
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• pp.175-182
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• 2023

APro, a modularized process-based total system performance assessment framework, was developed at the Korea Atomic Energy Research Institute (KAERI) to simulate radionuclide transport considering coupled thermal-hydraulic-mechanical-chemical processes occurring in a geological disposal system. For reactive transport simulation considering geochemical reactions, COMSOL and PHREEQC are coupled with MATLAB in APro using an operator splitting scheme. Conventionally, coupling is performed within a MATLAB interface so that COMSOL stops the calculation to deliver the solution to PHREEQC and restarts to continue the simulation after receiving the solution from PHREEQC at every time step. This is inefficient when the solution is frequently interchanged because restarting the simulation in COMSOL requires an unnecessary setup process. To overcome this issue, a coupling scheme that calls PHREEQC inside COMSOL was developed. In this technique, PHREEQC is called through the "MATLAB function" feature, and PHREEQC results are updated using the COMSOL "Pointwise Constraint" feature. For the one-dimensional advection-reaction-dispersion problem, the proposed coupling technique was verified by comparison with the conventional coupling technique, and it improved the computation time for all test cases. Specifically, the more frequent the link between COMSOL and PHREEQC, the more pronounced was the performance improvement using the proposed technique.