• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.101-111
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• 2005

The objectives of this study we to assess the extent and degree of environmental contamination and to draw general conclusions on the fate of toxic elements derived from mining activities in Korea. 인t abandoned mines with four base-metal mines and four Au-Ag mines were selected and the results of environmental surveys in those areas were discussed. In the base-metal mining areas, the Sambo Pb-Zn-barite, the Shinyemi Pb-Zn-Fe, the Geodo Cu-Fe and the Shiheung Cu-Pb-Zn mine, significant levels of Cd, Cu, Pb and Zn were found in mine dump soils developed over mine waste materials, tailings and slag. Furthermore, agricultural soils, stream sediments and stream water near the mines were severely contaminated by the metals mainly due to the continuing dispersion downstream and downslope from the sites, which was controlled by the feature of geography, prevailing wind directions and the distance from the mine. In e Au-Ag mining areas, the Kubong, the Samkwang, the Keumwang and the Kilkok mines, elevated levels of As, Cd, Cu, Pb and Zn were found in tailings and mine dump soils. These levels may have caused increased concentrations of those elements in stream sediments and waters due to direct dis-charge downstream from tailings and mine dumps. In the Au-Ag mines, As would be the most characteristic contaminant in the nearby environment. Arsenic and heavy metals were found to be mainly associated with sulfide gangue minerals, and mobility of these metals would be enhanced by the effect of oxidation. According to sequential extraction of metals in soils, most heavy metals were identified as non-residual chemical forms, and those are very susceptible to the change of ambient conditions of a nearby environment. As application of pollution index (PI), giving data on multi-element contamination in soils, over 1.0 value of the PI was found in soils sampled at and around the mining areas.

• Journal of radiological science and technology
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• v.26 no.2
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• pp.57-61
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• 2003

The purpose of this study is to compare both 1.5T and 4.7T in Praietal White matter material Phantom using the same methodology at both field strengths. Data at both field strengths are compared in terms of $T_2$ relaxation times, line widths and SNRs MR imaging and $^1H$ MR spectroscopy were performed on GE 1.5T SIGNA system and Broker Biospec 4.7T/30 MRI/MRS system. After phantom axial scan $^1H$ MRS was obtained from T2 weighted image by 3-dimensional localization technique(PRESS : Point RE solved spectroscopy Sequence) this phantom is composed of an aqueous solution 36.7 mmol/L of NAA, 25.0 mmol/L of Cr, 6.3 mmol/L of choline chloride, 30.0 mmol/L or Glu, and 22.5 mmol/L of MI(adjusted to a pH of 7,15 in a phosphate buffet). Data processed using software developed inhouse. At 1.5T, T2 relaxation times for Cho, Cr, and NAA were $0.41{\pm}0.07,\;0.26{\pm}0.04,\;0.46{\pm}0.07$ while at 4.7T they were $0.17{\pm}0.03,\;0.14{\pm}0.05,\;0.20{\pm}0.03$ respectively. At 1.5T, line widths for water, Cho, Cr and NAA were $2.9{\pm}0.7,\;1.6{\pm}0.7,\;1.7{\pm}0.8,\;2.2{\pm}0.02Hz$ while at 4.7T they were $5.2{\pm}1.1,\;4.6{\pm}1.9,\;4.01{\pm}1.8,\;4.8{\pm}1.9Hz$ respectively. It can be seen that $T_2$ relaxation times were significantly shorter at 4.7 compared to 1.5T and that the line widths were also broader. The average SNRs for NAA for subjects at short and long TEs were $23.5{\pm}11.3$ at TE=20 msec ; $15.4{\pm}7.7$ at TE=272 msec at 1.5T and $40{\pm}8.3$ and $17{\pm}3.5$ respectively at 4.7T higher field strength is superior because of improved sensitivity and chemical shift dispersion. However these improvements are partially offset by increased line widths and decrease $T_2$ relaxation times, which act to reduce both sensitivity and resolution. In our experiments with the equipment available to us, 4.7T proton spectra at short TEs exhibit moderately improved sensitivity compared to 1.5T.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.69-76
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• 1995

This study was concentrated on the subject of chou formation and physicochemical characteristics on medium flour mixed with 0, 25, 50, 75, 100% of rice flour in order to clarify the possibility to substitute rice flour for wheat flour on chou preparation. The water holding capacity, swelling power, and maximum viscosity were higher in rice flour than those in medium flour but the initial pasting temperature was equal to 65$^{\circ}C$ in the two flour groups. The ratio of setback during cooling became 0.94 in the rice flour and 1.14 in the medium flour. So, the rice flour showed a slow tendency during gel formation as compared with the medium flour. The volumes of the rice choux were ranged from 80.0% to 89.0% according to the mixing ratio of medium flour as compared with that of the chou of wheat flour. But, the choux formation were increased as much as 108.8% out the paste added gelation of glutinous substance and 124.4% at the paste added Span20 of emulsifier compared to the non-addition treatment. The paste of rice flour added gelatin and Span20 showed better dispersion of components, especially, the small granules of lipid were fairly or plentifully dispersed in the paste added Span20 due to emulsifying activity. In sensory evaluation, the chou of l00% rice flour was inferior to that of medium flour on cavity-forming but the choux of wheat flour mixed with 25%, 50%, and 75% of rice flour were equal or superior to that of medium flour on all characteristics tested such as appearance, surface color, cavity-forming, chewiness, and taste. There were no significant differences on the cavity-forming expansion and taste between choux of rice flour and wheat flour Therefore, the results of this study made conclusion that rice flour would be substituted for wheat flour on the chou preparation.

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.45-54
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• 2012

We investigated environmental characteristics of the tidal flat oyster aquafarms to clarifyeffects of the tidal flat environmental factors on growth and mortality of the tidal flat oyster Crassostrea gigas by the Net Bag Rack Culture System in two districts in Western Korea. In this study, we have carried out the basic environmental investigation on growth of the single tidal flat, water quality and sediments, etc. in Taean and Seosan districts, Choongcheongnam-do, where the single tidal flat oyster aquaculture have been performed by the net bag rack culture system. In June 2011 when the final survey carried out at the two districts in western Korea, the mortality in Seosan district was higher than that in Tae-an district. Judging from the results of growth and mortality of the single tidal flat oysters investigated at two sites of Jinsan-ri in Taean and Chang-ri in Seosan districts, two results of Taean district showed higher growth and lower mortality than those of Seosan district. It is assumed that the proper acceptable density possible for growth of the tidal flat seeds and the secure of economics, in case of plastic cultivate net with the size of $50{\times}80cm$, are about 200 individuals. In this study, It was clarified that selection of the suitable sites, the input into the net bag of high quality oyster seeds and selective dispersion in the optimal density of the single tidal flat oyster have an effect on growth and mortality of the tidal flat oyster.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.2
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• pp.51-61
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• 2010

Surface particulate organic carbon (POC) concentration was measured in the Northeastern Gulf of Mexico on 9 cruises from November 1997 to August 2000 to investigate the seasonal and spatial variability related to synchronous remote sensing data (Sea-viewing Wide Field-of-view Sensor (SeaWiFS), sea surface temperature (SST), sea surface height anomaly (SSHA), and sea surface wind (SSW)) and recorded river discharge data. Surface POC concentrations have higher values (>100 $mg/m^3$) on the inner shelf and near the Mississippi Delta, and decrease across the shelf and slope. The inter-annual variations of surface POC concentrations are relatively higher during 1997 and 1998 (El Nino) than during 1999 and 2000 (La Nina) in the study area. This phenomenon is directly related to the output of Mississippi River and other major rivers, which associated with global climate change such as ENSO events. Although highest river runoff into the northern Gulf of Mexico Coast occurs in early spring and lowest flow in late summer and fall, wide-range POC plumes are observed during the summer cruises and lower concentrations and narrow dispersion of POC during the spring and fall cruises. During the summer seasons, the river discharge remarkably decreases compared to the spring, but increasing temperature causes strong stratification of the water column and increasing buoyancy in near-surface waters. Low-density plumes containing higher POC concentrations extend out over the shelf and slope with spatial patterns and controlled by the Loop Current and eddies, which dominate offshore circulation. Although river discharge is normal or abnormal during the spring and fall seasons, increasing wind stress and decreasing temperature cause vertical mixing, with higher surface POC concentrations confined to the inner shelf.