• The Journal of the Petrological Society of Korea
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• v.4 no.1
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• pp.49-58
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• 1995

Staurolite-biotite-andalusite-garnet (SBAG) assemblage and its sub-assemblages (SBA and SBG) commonly occur in the Dueumri Formation near the Chunyang granite, belonging to andalusite and sillimanite zones. The occurrence of the SBAG mineral assemblage is unusual because it is univariant in the $K_2O-FeO-MgO-Al_2O_3-SiO_2-H_2O$ (KFMASH) model system. We used projection and singular value decomposition (SVD) methods to investigate the equilibrium relationship between SBAG and its sub-assemblage. The SVD modelling of single specimen containing the SBAG assemblage suggests no reaction relationship with respect to mass-balance. Thus, the SBAG assemblages are stabilized by non-KFMASH component. On the other hand, the AFM-Mn projection suggests a reaction relationship between SBAG and its sub-assemblage because they intersect each other in this composition space. The SVD modelling, however, suggests no reaction relationship between these assemblages. Thus, the SBAG assemblages are likely to be stabilized by the variation in bulk-rock composition and/or 1.1~2,. The stable occurrence of staurolite in the sillimanite zone is compatible with pressure estimates from the garnet-plagioclase-biotite-muscovite geobarometer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.153-153
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• 2008

최근 투명전극물질이 LCD, 박막태양전지, smart window, 유기발광소자 등에 폭넓게 이용됨에 따라 그 수요가 급격이 늘어나고 있다. 이러한 투명전극 물질로는 Al : ZnO, Ga : ZnO, $MgIn_2O_4$, $AgSbO_3$, $InGaZnO_4$, ITO, Zn:ITO 등이 있으며 이중 ITO 계 산화물은 우수한 전기적 특성을 바탕으로 이미 상용화 되어있는 상태이다. 그러나 ITO 계 산화물은 indium 의 희소성과 높은 가격 때문에 폭 넓은 분야의 상용화가 어려운 실정이며, 수소 플라즈마 분위기에 화학적으로 불안정한 특성은 Si 박막태양전지 응용에 큰 문제가 되고 있다. 이에 본 연구는 박막태양전지용 ITO 계 투명전극의 indium양을 줄이면서 화학적으로 안정하고, 전기적 특성이 향상된 박막을 제조하기 위해 combinatorial sputter를 이용하여 Zn의 도핑량을 연속적으로 변화시킨 ITO 박막을 제조하였다. 또한 광학적 전기적 특성의 향상을 위해 vacuum, $H_2$, $O_2$ 분위기에서 열처리 후 각 박막의 특성 변화를 관찰하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.189-190
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• 2011

Cu가 기존 배선물질인 Al을 대체함에 따라 resistance-capacitance (RC) delay나 electromigration (EM) 등의 문제들이 어느 정도 해결되었다. 그러나 지속적인 배선 폭의 감소로 배선의 저항 증가, EM 현상 강화 그리고 stability 악화 등의 문제가 지속적으로 야기되고 있다. 이를 해결하기 위한 방법으로 Cu alloy seed layer를 이용한 barrier 자가형성 공정에 대한 연구를 진행하였다. 이 공정은 Cu 합금을 seed layer로 사용하여 도금을 한 후 열처리를 통해 SiO2와의 계면에서 barrier를 자가 형성시키는 공정이다. 이 공정은 매우 균일하고 얇은 barrier를 형성할 수 있고 별도의 barrier와 glue layer를 형성하지 않아 seed layer를 위한 공간을 추가로 확보할 수 있는 장점을 가지고 있다. 또한, via bottom에 barrier가 형성되지 않아 배선 전체 저항을 급격히 낮출 수 있다. 합금 물질로는 초기 Al이나 Mg에 대한 연구가 진행되었으나, 낮은 oxide formation energy로 인해 SiO2에 과도한 손상을 주는 문제점이 제기되었다. 최근 Mn을 합금 물질로 사용한 안정적인 barrier 형성 공정이 보고 되고 있다. 하지만, barrier 형성을 하기 위해 300도 이상의 열처리 온도가 필요하고 열처리 시간 또한 긴 단점이 있다. 본 실험에서는 co-sputtering system을 사용하여 Cu-V 합금을 형성하였고, barrier를 자가 형성을 위해 300도에서 500도까지 열처리 온도를 변화시키며 1시간 동안 열처리를 실시하였다. Cu-V 공정 조건 확립을 위해 AFM, XRD, 4-point probe system을 이용하여 표면 거칠기, 결정성과 비저항을 평가하였다. Cu-V 박막 내 V의 함량은 V target의 plasma power density를 변화시켜 조절 하였으며 XPS를 통해 분석하였다. 열처리 후 시편의 단면을 TEM으로 분석하여 Cu-V 박막과 SiO2 사이에 interlayer가 형성된 것을 확인 하였으며 EDS를 이용한 element mapping을 통해 Cu-V 내 V의 거동과 interlayer의 성분을 확인하였다. PVD Cu-V 박막은 기판 온도에 큰 영향을 받았고, 200 도 이상에서는 Cu의 높은 표면에너지에 의한 agglomeration 현상으로 거친 표면을 가지는 박막이 형성되었다. 7.61 at.%의 V함량을 가지는 Cu-V 박막을 300도에서 1시간 열처리 한 결과 4.5 nm의 V based oxide interlayer가 형성된 것을 확인하였다. 열처리에 의해 Cu-V 박막 내 V은 SiO2와의 계면과 박막 표면으로 확산하며 oxide를 형성했으며 Cu-V 박막 내 V 함량은 줄어들었다. 300, 400, 500도에서 열처리 한 결과 동일 조성과 열처리 온도에서 Cu-Mn에 의해 형성된 interlayer의 두께 보다 두껍게 성장 했다. 이는 V의 oxide formation nergyrk Mn 보다 작으므로 SiO2와의 계면에서 산화막 형성이 쉽기 때문으로 판단된다. 또한, V+5 이온 반경이 Mn+2 이온 반경보다 작아 oxide 내부에서 확산이 용이하며 oxide 박막 내에 여기되는 전기장이 더 큰 산화수를 가지는 V의 경우 더 크기 때문으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.289-299
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• 2011

We studied the characteristics of pollutant concentrations in 9 streams that flow into Shihwa Lake in order to provide the scientific data for effective implementation of total pollution loads management system (TPLMS) of the Lake. Suspended solid (SS), chemical oxygen demand (COD), dissolved nutrients ($NO_2$, $NO_3$, $NH_4$, $PO_4$ and $SiO_2$), total phosphorus (TP) and total nitrogen (TN) in stream water from industrial complexes, urban and agricultural regions were determined. Pollutant concentrations in December were higher than that in other sampling periods. COD concentration from industrial complex region with average of 12.6 mg/L was 2 times higher those from urban region (6.6 mg/L) and agricultural region (5.9 mg/L). TP concentration from industrial region also showed higher concentration than other regions. TN concentration in stream water was 5.89 mg/L for industrial region, 3.02 mg/L for urban region and 5.27 mg/L for agricultural region, respectively, suggesting inflow of TN due to fertilizer usage in agricultural field. Relative percentage of nitrogen compounds in TN follows the sequence: $NH_4$ (35.1%) > $NO_2$ (20.0%) > DON (22.8%) > PON (8.9%) > $NO_2$ (3.2%). Concentrations of dissolved nutrients, TP and TN in stream water were 3.2~37.2 times higher than that in Shihwa Lake seawater, therefore large amount of pollutants may be directly entered into Shihwa Lake without any treatment. For Gunja stream of industrial region, pollutants at midstream showed relatively higher concentration compared to upstream and downstream. It is necessary to manage the illegal discharging of sewage and waste water. Our results provide valuable informations on the estimation and reduction of total pollutant loads in the process of establishing adequately strategic and implemental plan of Shihwa Lake TPLMS.

• Korean Journal of Materials Research
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• v.32 no.6
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• pp.301-306
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• 2022

This study explored the possibility of forming a coating layer containing alginic acid on the surface of a magnesium alloy to be used as a biomaterial. We formed a coating layer on the surface of a magnesium alloy using a plasma electrolytic oxidation process in an electrolytic solution with different amounts of alginic acid (0 g/L ~ 8 g/L). The surface morphology of all samples was observed, and craters and nodules typical of the PEO process were formed. The cross-sectional shape of the samples confirmed that the thickness of the coating layer became thicker as the alginic acid concentration increased. It was confirmed that the thickness and hardness of the sample significantly increase with increasing alginic acid concentration. The porosity of the surface and cross section tended to decrease as the alginic acid concentration increased. The XRD patterns of all samples revealed the formation of MgO, Mg₂SiO₄, and MgF₂ complex phases. Polarization tests were conducted in a Stimulate Body Fluid solution similar to the body's plasma. We found that a high amount of alginic acid concentration in the electrolyte improved the degree of corrosion resistance of the coating layer.

• Economic and Environmental Geology
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• v.30 no.1
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• pp.35-49
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• 1997

The coal formation of the Deokpyeong area are interbedded along metapelites of the Ogcheon Supergroup, which are composed mainly of graphite, quartz, muscovite and associated with small amounts of biotite, chlorite, pyrite and barite. The ratios of $SiO_2/Al_2O_3$, $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ of the coaly metapelite are variable and wide range from 1.80 to 10.21, from 27.8 to 388.8 and from 7.6 to 61.8, respectively. These coal formation were deposited in basin of marine environments, and the REE of these rocks are not influenced with metamorphism and hydrothermal alterations on the basis of $Al_2O_3$ versus La, La against Ce, the ratios of La/Ce (0.19 to 0.99) and Th/U (0.02 to 4.75). These rocks also show much variation in $La_N/Yb_N$ (1.19 to 22.89), Th/Yb (0.14 to 21.43) and La/Th (0.44 to 13.67), and their origin is explained by derivation from a mixture of sedimentary and igneous rocks. The wide range in trace and REE element characteristics as Co/Th (0.12 to 2.78), La/Sc (0.33 to 10.18), Sc/Th (0.57 to 5.73), V/Ni (8 to 2347), Cr/V (0.02 to 0.67) and Ni/Co (1.56 to 32.95) of these coaly metapelites argues for inefficient mixing of the various source lithologies during sedimentation. Deep to pale green barium-vanadium muscovites (vanadium-oellacherite) have been found in this coal formations. Modes of occurrence and grain size of muscovite are heterogeneous, but most of the barium and vanadium-bearing muscovites occur along the boundaries between graphite and quartz grains, ranging from 200 to $350{\mu}m$ in length and from 40 to $60{\mu}m$ in width. Results of X-ray diffraction data of the minerals characterized to be monoclinic system with $a=5.249{\AA}$, $b=8.939{\AA}$, $c=20.924{\AA}$ and ${\beta}=95.894^{\circ}$. Representative chemical formula of the muscovite was $(Na_{0.09}K_{1.44}Ba_{0.46})(Al_{2.75}Ti_{0.07}V_{0.56}Fe_{0.08}Mg_{0.50})(Si_{6.12}Al_{1.88})O_{22}$. The V possibly substitute octahedral Al, and the Ba is coupled substitution of $K^+Si^{4+}=Ba^{2+}Na^+Ca^{2+}$, which compositional ranges of V and Ba are from 0.42 to 0.69 and from 0.34 to 0.56 based on $O_{22}$, respectively. Formation mechanism of the barium-vanadium muscovites in the coaly metapelite is shown that the formed by high pressure and temperature from regional metamorphism origanated during diagenesis at the interface between a basinal brine and organic matter.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.659-665
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• 2008

This study is about zeolite synthesis from the sewage sludge incinerator fly ash of "S" sewage treatment center located in Seoul. For this purpose, the properties of raw fly ash as starting material, the hydrothermal conditions for zeolite synthesis and the environmental applicabilities of synthesized zeolites were examined. Fly ash from sewage sludge incinerator has large quantities of SiO$_2$ and Al$_2$O$_3$ and their contents are 42.8 wt.% and 21.2 wt.% respectively. So fly ash is considered to be possible starting material for zeolite synthesis. The results from leaching test of fly ash showed that the concentration of hazardous metals were very low as compared with the Korea leaching standard of the Waste Management Law. But the concentration from total recoverable test of fly ash were higher than the fertilizer standard of Fertilizer Management Law. Major zeolite products synthesized by hydrothermal reaction are analcime in teflon vessel and zeolite P1 in borosilicate flask. Optimum conditions for the synthesis of analcime were 1 N of NaOH concentration, 16 hour of reaction time and 135$^{\circ}C$ of reaction temperature. For the zeolite P1 formation, the proper conditions were demonstrated to be 5 N of NaOH concentration, 16 hour reaction time and 130$^{\circ}C$ of reaction temperature in this study. Hazardous metal contents in the analcime product are similar with those in raw fly ash. In case of the zeolite P1, the contents are reduced to nearly a half. Raw fly ash and the analcime product showed NH$_4{^+}$ ion exchange capacity of 0$\sim$1.0 mg of NH$_4{^+}$g$^{-1}$ and 3.0$\sim$7.4 mg of NH$_4{^+}$g$^{-1}$, respectively. However, the zeolite P1 product reached exchange capacity to 14.6$\sim$17.8 mg of NH$_4{^+}$g$^{-1}$. This values are in the range of those of natural clinoptilolite and phillipsite. From this point of view, zeolite synthesis from sewage treatment sludge incinerator fly ash is a good alternative for solid waste recycling.

• Journal of the Korean Professional Engineers Association
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• v.34 no.1
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• pp.59-65
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• 2001

Imported China Jades are mostly talc and serpentine groups, and that's occured troubles for our health and life of living organism. Serpentine is a group of common rock-forming minerals having the formula:(Mg$.$Fe)$^3$Si$_2$O$\_$5/(OH)$_4$. Sometime, simulated by nephrite or jade and translucent varieties we used for ornamental and decorative purposes. But it's forbid by heating materials for sauna and heating mats etc. that reason are it's occured asbestos dusts(chrysotile dusts) easily by the beating operations.

• Journal of the Korean Professional Engineers Association
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• v.34 no.1
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• pp.66-73
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• 2001

Imported China Jades are mostly talc and serpentine groups, and that's occured troubles for our health and life of living organism. Serpentine is a group of common rock-forming minerals having the formula : (Mg$.$Fe)$_3$Si$_2$O$\_$5/(OH)$_4$. Sometime, simulated by nephrite or jade and translucent varieties are used for ornamental and decorative purposes. But it's forbid by beating materials for sauna and heating mats etc. that reason are it's occured asbestos dusts (chrysotile dusts) easily by the heating operations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.347-355
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• 1986

The Sonakdong river is very important water source not only for agricultural water of Kimhae field but also for fishery water. Recently the middle and lower areas of the river have the tendency to be heavily contaminated by domestic sewage and agricultural chemicals. Fifty six water samples were collected from 8 stations from July to December in 1985 for the experiment (Fig. 1). To evaluate the water quality, pH, water temperature, electrical conductivity, chloride ion, nutrients ($NO^{-}_{2}-N,\;NO^{-}_{3}-N,\;NH^{+}_{4}-N,\;PO^{3-}_{4}-P,\;SiO_2-Si$), total coliform, fecal coliform, and fecal streptococcus were determined. Range and mean value of the samples were as follows; pH $6.3{\sim}9.4$, 7.91; water temperature $6.1{\sim}34.8^{\circ}C,\;23.88^{\circ}C$; electrical conductivity (from St. A to G) $1.575{\times}10^2{\sim}30.50{\times}10^2{\mu}{\mho}/cm,\;6.57{\times}10^2{\mu}{\mho}/cm$; chloride ion $23.5{\sim}14,300mg/l$, 770.0mg/l; nitrite-nitrogen $0.007{\sim}0.110mg/l$, 0.053mg/l; nitrate-nitrogen $0.001{\sim}1.638mg/l$, 0.649 mg/l; ammonia-nitrogen $0.017{\sim}4.200mg/l$, 0.497mg/l; phosphate-phoshorus $0.011{\sim}0.281mg/l$, 0.086mg/l; and silicate-silicious $2.4{\sim}6.5mg/l$, 4.43mg/l. Electrical conductivity and chloride ion of the station F(Chomanpo) were $2.676{\times}10^2{\mu}{\Omega}cm$ and 123.99mg/l which were lower than those of others. Among the analyzed nutrients, silicate-silicious concentration was the highest through all the samples. The bacterial density of the samples ranged $36{\sim}110,000/100ml$ for total coliform, $15{\sim}46,000/100ml$ for fecal coliform and $3.6{\sim}15,000/100ml$ for fecal streptococcus. The range and the mean of the TC/FC ratio were $3.0{\sim}9.6$, 5.51 and those of the FC/FS ratio were $1.1{\sim}9.2$, 6.19, respectively. On the other hand, fecal coliform was not detected in about $78\%$ of the water samples examined. Composition of coliform was $52\%$ Escherichia coli group, $3\%$ Citrobacter freundii group, $13\%$ Enterobacter aerogenes group and $31\%$ others.