• Economic and Environmental Geology
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• v.38 no.1
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• pp.91-99
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• 2005

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur mineral pyrite($FeS_2$). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this paper the generation characteristics and the prediction of ARD of various cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Fourteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.23-29
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• 2011

The oxidation slag has been widely used in civil engineering project, whereas the reduced slag from electric furnace has yet to be applied. Consequently in order to find out the recycling method in civil engineering field, the mineral compositions of the reduced slag were analyzed and some tests on water quality were performed to estimate the potential release of toxic compounds. Slag-soil mixtures of 0, 10, 20 and 30%(dry weight) soil were prepared in lysimeter columns and the effluents were collected with the period of one, two and four week options in closed system, respectively. The result from qualitative and quantitative analysis using X-ray Diffraction(XRD) and X-ray Fluorescence(XRF) indicates that the main mineral of the reduced slag is $Ca_2(SiO_4)$, a kind of calcium silicate. Also, the leaching medium analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) showed that main heavy metals such as Al, Fe and Mn are included in the reduced slag due to the effect of steel production process. It can be seen that the leachate does not violate the regulation guide line of waste material of heavy metal. Also the pH levels were increased from pH 6.9 for 0% soil to pH 10 for 30% soil. However the influence on leachate circulation period of one through four weeks was negligible.

• Clean Technology
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• v.29 no.3
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• pp.185-192
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• 2023

This study was conducted to obtain basic process simulation data before conducting pyrolysis experiments for the development of a thermochemical conversion system by recirculation of heat carrier and gases thereby. In this study, polypropylene (PP) was used as a pyrolysis sample material as an alternative to waste plastics, and fluid sand was used as a heat transfer medium in the system. Manganese (Mn) was chosen as the catalyst for the pyrolysis experiment, and the catalyst pyrolysis was performed by impregnating it in the sand. The basic properties of PP were analyzed using a thermogravimetric analyzer (TGA), and liquid oil was generated through catalytic pyrolysis under a nitrogen atmosphere at 600℃. The carbon number distribution of the generated liquid oil was confirmed by GC/MS analysis. In this study, the effects of the presence and the amount of Mn loading on the yield of liquid oil and the distribution of hydrocarbons in the oil were investigated. When Mn/sand was used, the residue decreased and the oil yield increased compared to pyrolysis using sand alone. In addition, as the Mn loading increased, the ratio of C₆~C₉ range gasoline in the liquid oil gradually increased, and the distribution of diesel and heavy oil with more carbon atoms than C₁₀ in the oil decreased. In conclusion, it was found that using Mn as a catalyst and changing the amount of Mn could increase the yield of liquid oil and increase the gasoline ratio in the product.

• Economic and Environmental Geology
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• v.40 no.3 s.184
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• pp.263-275
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• 2007

The purpose of this study was to show the pollution characteristics of hazardous elements from roadside dust in the Gwangju city. We collected 47 samples from November to December in 2004 and separated four groups such as residential area, industrialized area, downtown area and heavy traffic area fer characteristics comparison on hazardous elements. Roadside dust mostly consisted of quartz, albite, microcline, muscovite in XRD analysis. Content of hazardous elements varied: As $3.4{\sim}11.9 ppm$, Cd $0.2{\sim}28.2 ppm$, Co $32{\sim}526 ppm$, Cr $25{\sim}526 ppm$, Cu $11{\sim}375 ppm$, Ni $14{\sim}247 ppm$, Pb $13{\sim}413 ppm$ and Zn $101{\sim}972 ppm$. Average contents of hazardous elements of Zn>Cu>Pb>Cr>Co>Ni>Cd. Content of hazardous elements was low in residential area, whereas that of heavy metal was much the same in both in heavy traffic area. Content of hazardous elements such as Cd, Co, Cr, Cu, Ni, Pb, Zn was found to be particularly high in industrialized area. According to these results it was possible to presume that industrialized area was affected by industry activity such as machinery, petrochemical, automobile and electronics industry. The SEM analysis, detected Pb, Cr, Ni, and Fe particles in samples of industrialized area contaminated by industry activity. The correlation coefficient table resulted from the samples of roadside dust showed that there was same direction increase of content between elements. In other words, when the content of Cd increase, Cr and Ni increase, as Cr increase, Cu and Ni increase, as Cu increase Ni increase and Pb increase Zn increase. Based on these results it was possible to predict and interpret similar contamination patterns in this study.

• Journal of Welding and Joining
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• v.32 no.6
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• pp.75-81
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• 2014

Usage of heavy metal element (Pb, Hg and Cd etc.) in electronic devices have been restricted due to the environmental banning of the European Union, such as WEEE and RoHS. Therefore, it is needed to develop the Pb-free solder plated ribbon in photovoltaic (PV) module. This study described that degradation characteristics of PV module under damp heat (DH, $85^{\circ}C$ and 85% R.H.) condition test for 1,000 h. Solar cell ribbons were utilized to hot dipping plate with Pb-free solder alloys. Two types of Pb-free solder plated ribbons, Sn-3.0Ag-0.5Cu (SAC305) and Sn-48Bi-2Ag, and an electroless Sn-40Pb solder hot dipping plated ribbon as a reference sample were prepared to evaluate degradation characteristics. To detect the degradation of PV module with the eutectic and Pb-free solder plated ribbons, I-V curve, electro-luminescence (EL) and cross-sectional SEM analysis were carried out. DH test results show that the reason of maximum power (Pm) drop was mainly due to the decrease fill factor (FF). It was attributed to the crack or oxidation of interface between the cell and the ribbon. Among PV modules with the eutectic and Pb-free solder plated ribbon, the PV module with SAC305 ribbon relatively showed higher stability after DH test than the case of PV module with Sn-40Pb and Sn-48Bi-2Ag solder plated ribbons.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.662-671
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• 2015

To enrich the genetic resource of microbial xylanases with high activity and stability under alkaline conditions, a xylanase gene (xynSL4) was cloned from Planococcus sp. SL4, an alkaline xylanase-producing strain isolated from the sediment of soda lake Dabusu. Deduced XynSL4 consists of a putative signal peptide of 29 residues and a catalytic domain (30-380 residues) of glycosyl hydrolase family 10, and shares the highest identity of 77% with a hypothetical protein from Planomicrobium glaciei CHR43. Phylogenetic analysis indicated that deduced XynSL4 is closely related with thermophilic and alkaline xylanases from Geobacillus and Bacillus species. The gene xynSL4 was expressed heterologously in Escherichia coli and the recombinant enzyme showed some superior properties. Purified recombinant XynSL4 (rXynSL4) was highly active and stable over the neutral and alkaline pH range from 6 to 11, with maximum activity at pH 7 and more than 60% activity at pH 11. It had an apparent temperature optimum of 70℃ and retained stable at this temperature in the presence of substrate. rXynSL4 was highly halotolerant, retaining more than 55% activity with 0.25-3.0 M NaCl and was stable at the concentration of NaCl up to 4M. The enzyme activity was significantly enhanced by β-mercaptoethanol and Ca²⁺ but strongly inhibited by heavy-metal ions and SDS. This thermophilic and alkaline- and salt-tolerant enzyme has great potential for basic research and industrial applications.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.523-526
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• 2004

There are few studies on toxic metals in fruits. Therefore, we examined contents of toxic metals in fruits (n=386) available in Korean markets. The samples were digested with acids, then analyzed by inductively coupled plasma spectrometer (ICP) or atomic absorption spectrophotometer (AAS) for lead (Pb), cadmium (Cd), and arsenic (As). The contents of mercury (Hg) were also determined using a mercury analyzer, Contents of toxic metals in fruits were as follows [minimum-maximum (mean), mg/kg]; Hg 0.0001-0.019 (0.001), Pb 0.001-0.410 (0.013), Cd 0.001-0.035 (0.000), and As 0.001-0.210 (0.017). Our results showed that metal contents in fruits in Korean markets were similar to those reported in other countries. Average weekly intakes of Hg, Pb, and Cd from fruits are about 1-2% of Provisional Tolerable Weekly Intakes (PTWI) set by FAO/WHO Joint Food Additive and Contaminants Committee for safety evaluation.

• Fashion & Textile Research Journal
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• v.20 no.2
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• pp.128-142
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• 2018

This study explores newborn clothing with regard to clothing type, construction, textiles, design, size, and label placement. Related consumer complaints are also analyzed. Analysis of 50 newborn clothing items revealed six types of newborn clothing: baenaet jeogori, baenaet gown, bodysuit, one-piece, shirt and pants set, and pants. The baenaet jeogori was the most common type, and the most commonly used fasteners were ties and snaps. The following characteristics were commonly observed: front opening, long raglan sleeves, mitten cuffs, cotton fabric, white/ivory color, animal print, contrast hem, $appliqu{\acute{e}}$, and size 60. In-depth interviews of 12 mothers with children under 24 months revealed that the baenaet jeogori was the most unsatisfactory type; the shirt and pants set and bodysuit were preferred. Interviewees were dissatisfied with types of openings, expressing a preference for snaps and complaining about ties, too many snaps, metal snaps, and shoulder openings. Overly wide or narrow sleeves resulted in improper fit, and long sleeves made it difficult to dress the baby. Interviewees required diverse sleeve length options. They were dissatisfied with heavy fabric for hot and warm seasons, and with labels attached inside clothing or outside near the neckline. Mothers with particularly small or big babies complained about limited sizes. To improve current newborn clothing, additional items such as shirt and pants sets or individual pants, front opening clothing with few snaps, proper sleeve fit with diverse length options, lightweight fabric for hot and warm seasons, label placement that avoids skin irritation, and size segmentation are recommended.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.107-107
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• 2003

The heavy metal cadmium is a xenobiotic toxicant of environmental and occupational concern and it has been classified as a human carcinogen. Inhalation of cadmium has been implicated in the development of emphysema and pulmonary fibrosis, but, the detailed mechanism by which cadmium induces adverse biological effects is not yet known. Therefore, we undertook the investigation of genes that are induced after cadmium exposure to illustrate the mechanism of cadmium toxicity For this purpose, we employed the polymerase chain reaction-based suppression subtractive hybridization technique. We identified 29 different cadmium-inducible genes in human peripheral mononuclear cells, such as macrophage migration inhibitory factor, lysophosphatidic acid acyltransferase-${\alpha}$, enolase-1${\alpha}$, VEGF, Bax, neuron-derived orphan receptor-1, and Nur77, which are known to be associated with inflammation, cell survival, and apoptosis. Induction of these genes by cadmium treatment was further confirmed by semi-quantitative reverse-transcription polymerase chain reaction. Further, we found that these genes were also induced after cadmium exposure in normal human lung fibroblast cell line, WI-38, suggesting potential use of this induction profile to monitor cadmium toxicity in the lung. Next, Nur77, one of cadmium-inducible genes, was further studied since the products of Nur77 are known to be involved in the apoptotic process of lung cells. Following cadmium treatment, Nur77 gene expression was increased at protein-level in A549 cells. Consistently, the reporter containing Nur77 binding sequence was activated by 2.5-fold after exposure to cadmium in reporter gene analysis by transient transfection experiments. When the plasmid encoding dominant negative Nur77 that represses the transcriptional function of wild-type Nur77 was transfected into A549 cells, the expression of Bax was significantly reduced, suggesting that induction of Nur77 was an important process in cadmium-induced apoptosis in the cells. Cadmium induced the expression of Nur77 in vivo, confirming the relevance of the data obtained in viro. Together our results suggest that Nur77 gene expression in exposure to cadmium leads apoptosis of lung cells which may cause pathological changes in lung.

• Analytical Science and Technology
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• v.9 no.2
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• pp.134-138
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• 1996

Cadmium was transported through the special carrier system into the cells of cotyledons, hypocotyls, and roots spring radish young plants. The transport of cadmium was inhibited by metabolic inhibitor, like DNP. The $K_m$ values for cadmium were 0.7 ppm for cotyledons, 1.72 ppm for hypocotyls, and 0.3 ppm for roots, and $V_{max}$ for cadmium was $40ppm{\cdot}h^{-1}{\cdot}g{\cdot}fresh\;weight^{-1}$ for cotyledons, $313ppm{\cdot}h^{-1}{\cdot}g{\cdot}fresh\;weight^{-1}$ for hypocotyls, and $606ppm{\cdot}h^{-1}{\cdot}g{\cdot}fresh\;weight^{-1}$ for roots. Cadmium cannot prove to be inducer for proline accumulation. Therefore, proline accumulation cannot be used as a marker to test the level of heavy metal pollution.