• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.1-9
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• 2008

The main purpose of this study is to accumulate the fundamental data representing groundwater of plastic film houses by means of water quality and its multivariate statistical analysis. Groundwater samples were collected in every two years since 2000 to 2004 from total 211 sites. According to the result of water quality analysis, ground water quality was suitable for irrigation purpose averagely. Correlation analysis showed that EC was highest positively correlated with $Mg^{2+}$ to 0.810(p<0.01), 0.776(p<0.01) in April and July, respectively. $NO_3-N$ was highest positively correlated with T-N to 0.794(p<0.01) in October. This result shows that it can lead to a different result even in similar case sometimes. Four factors were extracted through factor analysis in April and July, but five factors were extracted in October. The proportions of cumulative variance by the factor were 64.9, 60.2, and 70.7 in April, July, and October, respectively. The first factor was highly related to anions and cations such as $Ca^{2+},\;Mg^{2+},\;Cl^-,\;{SO_4}^{2-}$, and EC in contrast to that of stream water. According to the cluster analysis, 211 sites are classified into four groups. Common type of ground water quality was shown in group A. The pH and $PO_4-P$ were highest in Group B. The anions and cations were highest in Group C. $COD_{Cr}$ was highest in Group D.

• The Journal of Engineering Geology
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• v.2 no.2
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• pp.173-200
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• 1992

The quality of groundwater in the central part of Taegu City is influenced by upstreams of Sin-stream and Beomeo-stream because the stream waters are main source of the groundwater, and chemical composition of the upstream waters has close relationship with andesite and monzonite in the igneous rock terrain. The pH of upstreams are weak acid ~ neutral in the igneous rock area and weak alkaline in the sedimentary rock area. Contents of $Ca^{2+}$ and $Mg^{2+}$ in the streams are apparently high, and $Na^{+}$ content is only slightly high in the sedimentary rock area. But $K^{+}$ content is lower in the Panyaweol formation area than in the monzonite area. The contents of heavy metals and $N0_3^{-}$ are also higher in the sedimentary rock area of residential sections and industrial complexes than those in the igneous rock area. The groundwater is contaminated in comparison to the upstream water of the igneous rock areas, and there are some differences in pollution level between the Panyaweol formation area of residential sections and the Haman formation area of industrial complexes. K, Na, Ca, Mg, Cl, $SO_4$ and $NO_3$ contents in the Haman formation area are relatively higher than those in the Panyaweol formation area. But pH is nearly equal in the two areas. The content of heavy metal ions is still lower than the drinking water standard of Korea and only slightly differs in the two sedimentary rock areas. But the groundwater in the Haman formation area is considerably contaminated by Kongdanstream and Dalseo-stream.

• Economic and Environmental Geology
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• v.32 no.4
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• pp.385-398
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• 1999

The Narim gold mine is located approimately 200km southeast of Seoul within the Muju mineralized district of the Sobaegsan gneiss complex, Korea. Environmental geochemistry were undertaken for various kinds of water (surface, ground and mine water) collected of April, September and November in 1998 from the narim mine creek. Hydrogeochemical compositions of water samples are characterized by the relatively significant enrichment of Na+K, alkali ions, $HCO_{3}$, $NO_{3}$, Cl and F in groundwater, wheras the mine and surface waters are relatively enriched in Ca+Mg, hea표 metals and $SO_{4}$. Therefore, the groundwaters belong to the (Na+Ca)-( $HCO_{3}+SO_{4}$) type, respectively. The pH and EC values of the non-mining creek surfers are relatively lower compared with those of the surface water of the mine and ore dump area. The d values ($\delta$D-8$\delta^{18}$O) of all kinds of water from the Narim mine creek are 5.8 to 13.1 The range of $\delta$D and $\delta^{18}$O values (relative to SMOW) are shown in distinct two groups as follows: for the April waters of -64.8 to -67.8$\textperthousand$ and -9.6 to -10.0$\textperthousand$(d value=10.1 to 13.1), and for the November waters of -65.9 to -70.2$\textperthousand$ and -9.3 to -9.6$\textperthousand$ (d value=5.8 to 7.9), respectively. This range variation indicates that two group water were composed of distinct waters with seasonal difference. Geochemical modeling showed that mostly toxic metals (As, Fe, Mn, Ni, Pb, Zn) may exist largery in the from of metal $(M2^+)$ and metal-sulfate $(MSO_4\;^{2-$\mid$),\; and \;SO_4^{2-$\mid$}$ concentration influenced the speciation of heavy metals in the meteoric water. These metals in the groundwater could be formed of $CO_3 \;and \;(OH)_3$ complex ions. Using computer program, saturation index of albite, calcite, dolomite in meteoric water show undersaturated and progreddively evolved toward the saturation state, however, ground and mine water are nearly saturated. The gibbsited water-mineral reaction and stabilities suggest that the weathering of silicate minerals may be stable kaolinite, illite and Nasmectite. The clay minerals will be transformed to more stable kaolinite owing to the contiunous reaction.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.74-85
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• 2013

Since the underground transportation system is a closed environment, indoor air quality problems may seriously affect many passengers' health. The purpose of this study was to understand $PM_{10}$ characteristics in the underground air environment and further to quantitatively estimate $PM_{10}$ source contributions in a Seoul Metropolitan subway station. The $PM_{10}$ was intensively collected on various filters with $PM_{10}$ aerosol samplers to obtain sufficient samples for its chemical analysis. Sampling was carried out in the M station on the Line-4 from April 21 to 28, July 13 to 21, and October 11 to 19 in the year of 2010 and January 11 to 17 in the year of 2011. The aerosol filter samples were then analyzed for metals, water soluble ions, and carbon components. The 29 chemical species (OC1, OC2, OC3, OC4, CC, PC, EC, Ag, Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Si, Ti, V, Zn, $Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) were analyzed by using ICP-AES, IC, and TOR after proper pretreatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the $PM_{10}$ sources and then six sources such as biomass burning, outdoor, vehicle, soil and road dust, secondary aerosol, ferrous, and brakewear related source were classified. The contributions rate of their sources in tunnel are 4.0%, 5.8%, 1.6%, 17.9%, 13.8% and 56.9% in order.

• The Korean Journal of Mycology
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• v.10 no.1
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• pp.33-39
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• 1982

Carpophores of ten Korean strains of Lentinus edodes (Berk.) Singer, an antitumor polysaccharide producing fungus, were extracted with 0.1N NaOH solution. The extracts were dialized for seven days in distilled water and lyophilized to produce crude polysaccharide powders. Thus obtained crude polysaccharide samples were assayed for sugar contents by colorimetric method with anthrone reagent. Among ten strains examined Lentinus edododes-DMC7 was found to be the richest strain in polysaccharide content of carpophores. By shake culture experiment for biomass production, L. edodes-DMC7 was found to be the second most productive strain among seven strains examined. Cultural characteristics of L. edodes-DMC7 were investigated by shake culture method. The best result was obtained when L. edodes-DMC7 was cultured in the medium containing glucose 8g, starch 80g, yeast extract 12g, $KH_2PO_4\;0.87g,\;MgSO_4{\cdot}7H_2O\;O.5g,\;CaCl_2\;0.3g,\;FeSO_4{\cdot}7H_2O\;10mg\;ZnSO_4{\cdot}7H_2O\;4mg,\;CuSO_4{\cdot}5H_2O\;lmg,\;MnCl_2{\cdot}4H_2O\;7mg\;per\;11\;at\;28^{\circ}C$, 180 rpm, for 12 days. Thus thirty-three grams of dry mycelia was obtained per one liter of medium.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.5
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• pp.543-553
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• 2010

Almost five million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan. As the subway system is typically a closed environment, indoor air pollution problems frequently occurs and passengers complain of mal-health impact. Especially $PM_{10}$ is well known as one of the major pollutants in subway indoor environments. The purpose of this study was to compare the indoor air quality in terms of $PM_{10}$ and to quantitatively compare its source contributions in a Seoul subway platform before and after installing platform screen doors (PSD). $PM_{10}$ samples were collected on the J station platform of Subway Line 7 in Seoul metropolitan area from Jun. 12, 2008 to Jan. 12, 2009. The samples collected on membrane filters using $PM_{10}$ mini-volume portable samplers were then analyzed for trace metals and soluble ions. A total of 18 chemical species (Ba, Mn, Cr, Cd, Si, Fe, Ni, Al, Cu, Pb, Ti, $Na^+$, $NH_4^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, and ${SO_4}^{2-}$) were analyzed by using an ICP-AES and an IC after performing proper pre-treatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the source of particulate matters. $PM_{10}$ for the station was characterized by three sources such as ferrous related source, soil and road dust related source, and fine secondary aerosol source. After installing PSD, the average $PM_{10}$ concentration was decreased by 20.5% during the study periods. Especially the contribution of the ferrous related source emitted during train service in a tunnel route was decreased from 59.1% to 43.8% since both platform and tunnel areas were completely blocked by screen doors. However, the contribution of the fine secondary aerosol source emitted from various outside combustion activities was increased from 14.8% to 29.9% presumably due to ill-managed ventilation system and confined platform space.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.243-251
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• 1997

In this paper, we have reported two interesting flow effects arising in the TRFGE sequence using water flow phantom. First, we have shown that the TRFGE sequence is indeed not affected by "in-flow" effect from the unsaturated spins flowing into the imaging slice. Second, the enhancement of "in-plane flow" signal in the readout gradient direction was observed when the TRFGE sequence was used without flow compensation. These two results have many interesting applications in MR imaging other than fMRI. Results obtained were also compared with the results obtained by the conventional gradient echo(CGE) imaging. Experiments were performed at 4.7T MRI/S animal system (Biospec, BRUKER, Switzerland). A cylindrical phantom was made using acryl and a vinyl tube was inserted at the center(Fig. 1). The whole cylinder was filled with water doped with $MnCl_2$ and the center tube was filled with saline which flows in parallel to the main magnetic field along the tube. Tailored RF pulse was designed to have quadratic ($z^2$) phase distribution in slice direction(z). Imaging parameters were TR/TE = 55~85/10msec, flip angle = $30^{\circ}$, slice thickness = 2mm, matrix size = 256${\times}$256, and FOV= 10cm. In-flow effect : Axial images were obtained with and without flow using the CGE and TRFGE sequences, respectively. The flow direction was perpendicular to the image slice. In-plane flow : Sagittal images were obtained with and without flow using the TRGE sequence. The readout gradient was applied in parallel to the flow direction. We have observed that the "in-flow" effect did not affect the TRFGE image, while "in-plane flow" running along the readout gradient direction enhanced the signal in the TRFGE sequence when flow compensation gradient scheme was not used.

• 한국해양학회지
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• v.7 no.1
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• pp.24-45
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• 1972

The Han River is an important water source in Seoul and neighbouring districts, for public and industrial supply, and for agriculture and fishery. Nowadays, more than six million inhabitants are supplied withe water from this river. The total length of the river is 470km, and has 17 10$\^$9/㎥ an average annual flow. The hydrographic characteristics at Seoul are 653㎥/sec in an average flow, 4,608㎥/sec in the maximum average flow, and 201㎥/sec in the minimum average flow. These are influenced in some degree by snowmelt in early spring, and greatly by the flood during summer. For the pollution problems, the periods of low flow are critical ones. As a rule they occur around the months November through June. Nowadays, most of the sewage from towns and industries is discharged untreated. Apart from domestic and industrial sewages, there are some discharges of mineral matter by mines in the upriver region. In general, water quality of the Han River is kept very clean and healthy until Kwangnaru of the upper region of Seoul. A large pollution, however, is received in the downstream by the domestic and industrial sewages of Seoul. It can be seen that dissolved oxygen, COD and BOD$\sub$5/ diminish markedly, and the intensity of almost every water parameter of the river continues to increase. Comparison of the figures for 1971 derived from a sampling point 40km downstream of Kwangnaru leads to the conclusion that hardness, Ca and Mg were no changed; alkalinity, Si and soluble- Fe were slightly increased; CO$\sub$2/, acidity, Cl, NO$\sub$2/-N, Cu, Zn and Al were increased in 2 and 3 times; total residue, total ignitious residue, COD, BOD$\sub$5/, NH$\sub$4/-N, PO$\sub$4/-P, Mn, Pb and total-Fe were increased in 4 to 7 times; and SO$\sub$4/, particulate-Fe and Cd were increased in 10 to 11 times. On the other hand, coliforms were increased in 650 times; fecal coliforms in 365 times; enterococci and total plate counts in 30 times, respectively. In view points of water quality standards, the down Han River water is now leveling out in Cd, coliforms and fecal coliforms for the agricultural use; in dissolved oxygen and some trace elements (Cu, Zn, Pb and Cd) for the fishery use; in ammonia, COD, BOD$\sub$5/, and Cd for the drinking use.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.653-662
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• 2006

Quartz veins from the Jukwangri area of Hwawon-myeon are epithermal quartz veins that are filling the NW or NE-trending faults within Precambrian metasedimentary rocks. Based on their prolongation and ore grades, No. 1 quartz vein can be traced for about 200 m and varies 0.1 to 3 m in thickness. Mineralization of No. 1 quartz vein can be divided into hypogene and supergene stages. Hypogene stage is associated with hydrothermal alteration minerals(phyllic and argillic zones) such as illite, sericite and sulfides such as pyrite, arsenopyrite, sphalerite. chalcopyrite, galena, argentian tetrahedrite. Supergene stage is composed of Fe-Mn oxide, Zn-Fe oxide and Pb oxide. Fluid inclusion data indicate that homogenization temperature and salinity of hypogene stage range from 187 to $306^{\circ}C$ and ken 0.0 to 6.2 wt.% eq. NaCl, respectively. They suggest that ore forming fluids were progressively cooled and diluted from mixing with meteoric water. Oxygen($-4.1{\sim}4.1%o$) and hydrogen($-107{\sim}-88%o$) isotope com-positions indicated that hydrothermal fluids were derived from meteoric and evolved by progressive mixing with meteoric water during mineralization.

• Polymer(Korea)
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• v.30 no.3
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• pp.196-201
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• 2006

Poly (ethylene glycol)-based diblock and triblock thermo- sensitive polyester copolymers were investigated for application on tissue engineering and injectable biomaterials in drug delivery system due to their nontoxicity, biocompatibility and biodegradability. We synthesized the diblock copolymers consisting of methoxy poly (ethylene glycol) (MPEG) (Mn=750 g/mole) and poly $(\varepsilon-caprolactone)$ (PCL) by ring opening polymerization of $\varepsilon-CL$ with MPEG as an initiator in the presence of HCl $Et_2O$. The effect of diblock copolymers on in vivo osteogenic differentiation of rat bone marrow stromal cells (BMSCS) with and without the presence of osteogenic supplements (dexamethasone) was investigated. Thin sections were cut from paraffin embedded tissues and histological sections were stained by H&E, von Kossa, and immunohistochemical staining for osteocalcin. In conclusion, dexamethasone containing thermo- sensitive hydrogel might be improved osteogenic differentiation of BMSCs. We expect the osteoinduction effect to be excellent when it uses stem cell or other osteogenic materials.