• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.75-75
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• 2018

Commercially pure titanium (CP-Ti) and Ti-6Al-4V alloys have been widely used in implant materials such as dental and orthopedic implants due to their corrosion resistance, biocompatibility, and good mechanical properties. However, surface modification of titanium and titanium alloys is necessary to improve osseointegration between implant surface and bone. Especially, when titanium oxide nanotubes are formed on the surface of titanium alloy, cell adhesion is greatly improved. In addition, plasma electrolytic oxide (PEO) coatings have a good safety for osseointegration and can easily and quickly form coatings of uniform thickness with various pore sizes. Recently, the effects of bone element such as magnesium, zinc, strontium, silicon, and manganese for bone regeneration are researching in dental implant field. The purpose of this study was researched on the surface morphology of PEO-treated Ti-6Al-4V alloy after anodic titanium oxide treatmentusing various instruments. Ti-6Al-4V ELI disks were used as specimens for nanotube formation and PEO-treatment. The solution for the nanotube formation experiment was 1 M $H_3PO_4$ + 0.8 wt. % NaF electrolyte was used. The applied potential was 30V for 1 hours. The PEO treatment was performed after removing the nanotubes by ultrasonics for 10 minutes. The PEO treatment after removal of the nanotubes was carried out in the $Ca(CH_3)_2{\cdot}H_2O+(CH_3COO)_2Mg{\cdot}4H_2O+Mn(CH_3COO)_2{\cdot}4H_2O+Zn(CH_3CO_2)_2Zn{\cdot}2H_2O+Sr(CH_2COO)_2{\cdot}0.5H_2O+C_3H_7CaO_6P$ and $Na_2SiO_3{\cdot}9H_2O$ electrolytes. And the PEO-treatment time and potential were 3 minutes at 280V. The morphology changes of the coatings on Ti-6Al-4V alloy surface were observed using FE-SEM, EDS, XRD, AFM, and scratch tester. The morphology of PEO-treated surface in 5 ion coating solution after nanotube removal showed formation or nano-sized mesh and micro-sized pores.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.68-71
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• 2002

The electromagnetic properties and thermal behavior of ferrite cores used in the blocking filter for PLC were investigated as a function of additives. The highest density of 4.98 $g/cm^2$ and permeability of 8221 were obtained to the specimen added $MoO_3$ 400 ppm, $SiO_2$ 100 ppm and CaO 200 ppm since the microstructures were compacted through reduction of pores in the specimen. The permeability was increased up to 13094 at $110^{\circ}C$ with increasing temperature of specimen, however, it was decreased precipitously to under 100 over $110^{\circ}C$. The exothermic behavior was observed that the temperature of specimens became $102^{\circ}C$ at 1MHz. In the consequence, the ferrite core developed by this research will maintain the stable electromagnetic properties since the temperature of ferrite core rose to $93^{\circ}C$ in the range of 10kHz to 450kHz bandwidth qualified for PLC.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.3
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• pp.199-203
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• 2006

In the late growth stage of rice plant, the growth declines even though they grow well in early growth stage. This phenomenon is called autumn declining and it often accompanies the infection of Helminthosporium leaf spot disease. This study was carried out to identify the related environmental factors and to establish the integrated control system of Helminthosporium Leaf Spot Disease in rice. The total area of infected paddy field by Helminthosporium leaf spot was 470 ha in 2000 and 1,004 ha in 2001, which occupied about 1% of the total paddy area in Gyeongbuk province, Korea. The ill-drained sandy paddy occupied 50% of the total area of infected paddy fields and followed by sandy paddy (28%). Comparing the content of soil elements between infected and normal paddy, it was clarified that the organic matter content of normal was higher than that of infected paddy and the contents of inorganic elements such as Mn, Fe, Zn and available $SiO_2$ were also higher in normal paddy. The results of comparing the inorganic elements between infected and normal rice plants also showed the same results. The contents of inorganic elements such as MgO, $SiO_2$, Fe, Mn were higher in normal rice plants. Especially highly significant difference of $SiO_2$ content on both soil and rice plants was noticeable.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.469-484
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• 2022

The Janggun Pb-Zn deposit has been known one of the four largest deposits (Yeonhwa, Shinyemi, Uljin) in South Korea. The geology of this deposit consists of Precambrian Weonnam formation, Yulri group, Paleozoic Jangsan formation, Dueumri formation, Janggum limestone formation, Dongsugok formation, Jaesan formation and Mesozoic Dongwhachi formation and Chungyang granite. This Pb-Zn deposit is hydrothermal replacement deposit in Paleozoic Janggum limestone formation. The wallrock alteration that is remarkably recognized with Pb-Zn mineralization at this deposit consists of mainly rhodochrositization and dolomitization with minor of pyritization, sericitization and chloritization. Wallrock alteration is divided into the five zones (Pb-Zn orebody -> rhodochrosite zone -> dolomite zone -> dolomitic limestone zone -> limestone or dolomitic marble) from orebody to wallrock. The white mica from wallrock alteration occurs as fine or medium aggregate associated with Ca-dolomite, Ferroan ankerite, sideroplesite, rutile, apatite, arsenopyrite, pyrite, sphalerite, galena, quartz, chlorite and calcite. The structural formular of white mica from wallrock alteration is (K_0.77-0.62Na_0.03-0.00Ca_0.03-0.00Ba_0.00Sr_0.01)_0.82-0.64(Al_1.72-1.48Mg_0.48-0.20Fe_0.04-0.01Mn_0.03-0.00Ti_0.01-0.00Cr_{0.00As0.01-0.00}Co_0.03-0.00Zn_0.03-0.00Pb_0.05-0.00Ni_0.01-0.00)_2.07-1.92 (Si_3.43-3.33Al_0.67-0.57)_4.00O₁₀(OH_1.94-1.80F_0.20-0.06)_2.00. It indicated that white mica from wallrock alteration has less K, Na and Ca, and more Si than theoretical dioctahedral micas. The white micas from wallrock alteration of Janggun Pb-Zn deposit, Yeonhwa 1 Pb-Zn deposit and Baekjeon Au-Ag deposit, and limestone of Gumoonso area correspond to muscovite and phengite and white mica from wallrock alteration of Dunjeon Au-Ag deposit corresponds to muscovite. Compositional variations in white mica from wallrock alteration of these deposits and limeston of Gumoonso area are caused by mainly phengitic or Tschermark substitution mechanism (Janggun Pb-Zn deposit), mainly phengitic or Tschermark substitution and partly illitic substitution mechanism (Yeonhwa 1 Pb-Zn deposit, Dunjeon Au-Ag deposit and Baekjeon Au-Ag deposit), and mainly phengitic or Tschermark substitution and partly illitic substitution or Na⁺ <-> K⁺ substitution mechanism (Gumoonso area).

• Economic and Environmental Geology
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• v.47 no.4
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• pp.363-379
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• 2014

The Haenam Pb-Zn skarn deposit is located at the Hwawon peninsula in the southwestern part of the Ogcheon Metamorphic Belt. The deposit is developed along the contact between limestone of the Ogcheon group and Cretaceous quartz porphyry. Petrography of ore samples, chemical composition of skarn and ore minerals, and geochemistry of the related igneous rocks were investigated to understand the characteristics of the skarn mineralization. Skarn zonation consists of garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone, pyroxene+garnet+quartz${\pm}$calcite zone, calcite+pyroxene${\pm}$garnet zone, quartz+calcite${\pm}$pyroxene zone, and calcite${\pm}$chlorite zone in succession toward carbonate rock. Garnet commonly shows zonal texture comprised of andradite and grossular. Pyroxene varies from Mn-hedenbergite to diopside as away from the intrusive rock. Chalcopyrite occurs as major ore mineral near the intrusive rock, and sphalerite and galena tend to increase as going away. Electron probe microanalyses revealed that FeS contents of sphalerite become decreased from 5.17 mole % for garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone to 2.93 mole %, and to 0.40 mole % for calcite+pyroxene${\pm}$garnet zone, gradually. Ag and Bi contents also decreased from 0.72 wt.% and 1.62 wt.% to <0.01 wt.% and 0.11 wt.%, respectively. Thus, the Haenam deposit shows systematic variation of species and chemical compositions of ore minerals with skarn zoned texture. The related intrusive rock, quartz porphyry, expresses more differentiated characteristics than Zn-skarn deposit of Meinert(1995), and has relatively high$SiO_2$ concentration of 72.76~75.38 wt.% and shows geochemical features classified as calc-alkaline, peraluminous igneous rock and volcanic arc tectonic setting.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.701-717
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• 2003

The objective of this study was to extensively estimate the air quality trends of the study area by surveying con-centration trends in months or seasons, after analyzing the mass concentration of PM-10 samples and the inorganic lements, ion, and total carbon in PM-10. Also, the study introduced to apply the PMF (Positive Matrix Factoriza-tion) model that is useful when absence of the source profile. Thus the model was thought to be suitable in Korea that often has few information about pollution sources. After obtaining results from the PMF modeling, the existing sources at the study area were qualitatively identified The PM-10 particles collected on quartz fiber filters by a PM-10 high-vol air sampler for 3 years (Mar. 1999∼Dec.2001) in Kyung Hee University. The 25 chemical species (Al, Mn, Ti, V, Cr, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, Ce, Pb, Si, N $a^{#}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$, C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$, TC) were analyzed by ICP-AES, IC, and EA after executing proper pre - treatments of each sample filter. The PMF model was intensively applied to estimate the quantitative contribution of air pollution sources based on the chemical information (128 samples and 25 chemical species). Through a case study of the PMF modeling for the PM-10 aerosols. the total of 11 factors were determined. The multiple linear regression analysis between the observed PM-10 mass concentration and the estimated G matrix had been performed following the FPEAK test. Finally the regression analysis provided source profiles (scaled F matrix). So, 11 sources were qualitatively identified, such as secondary aerosol related source, soil related source, waste incineration source, field burning source, fossil fuel combustion source, industry related source, motor vehicle source, oil/coal combustion source, non-ferrous metal source, and aged sea- salt source, respectively.ively.y.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.3
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• pp.129-140
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• 1998

In this study two sites were selected to investigate groundwater contamination and spatial relationship between pollution level and its source. One is the Asan area, agricultural district where pollution sources are scattered. The other is the Gurogu area of Seoul city, industrial district where industrial complex and residential areas are located. Groundwater samples collected from these districts were analysis for chemical constituents. The attribute value files of the chemical constituents of groundwater and the spatial layers have been constructed and the pollution properties have been investigated to find out spatial relationships between the groundwater constituents and pollution sources using CIS. Relatively high contents of Si and HCO$_3$ in groundwater from the Asan area reflect the effect of water-rock interaction, whereas high contents of Cl, NO$_3$, SO$_4$and Ca in groundwater from the Gurogu area are due to the pollution of various sources. Pollution over the critical level of Korean Dinking Water Standard has been investigated from 15 sampling sites out of 40 in the Asan area, and 33 sampling sites out of 51 in the Gurogu area. There is pollution of NO$_3$, Cl, Fe, Mn, SO$_4$and Zn in groundwater from the Gurogu area, and that of NO$_3$, SO$_4$and Zn in groundwater from the Asan area. Principal pollution in both areas is NO$_3$contamination. Deep groundwater from the Asan area is not contaminated with NO$_3$except for one site and most of shallow groundwater near the potential point sources such as factory and stock farm is contaminated seriously. Groundwater from the Gurogu area has been already polluted seriously considering the fact of contamination of deep groundwater. This study reports a spatial relationship between the pollution level and pollution source using GIS.

• Journal of Environmental Science International
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• v.9 no.3
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• pp.241-252
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• 2000

Twenty-two water samples(fifteen groundwater and seven geothermal water samples) were collected to elucidate chemical characteristics of the ground and geothermal waters in the Haeundae hot spring area and its vicinity. Major and honor elements were analyzed for ground and geothermal water samples. The concentrations of $K^+$, Na+$, $Ca^{2+}$, $SO_4^{2-}$, $Cl^-$, ^F^-$ and $SiO_2$ were higher in the geothermal water samples than the groundwater samples except $HCO_3^- and Mg^{2+}$ ions. Based on the contents of Fe, Zn, Cu, Al, Mn and Pb, some of the ground and geothermal water samples are contaminated by anthropogenic sources. The ground waters shown on the Piper diagram belong to $Ca-HCO_3$ type, while the geothermal waters Na-Cl type. The graphs of $Cl^-$ versus $Na^+$, $Ca^{2+}, Mg^{2+}, K^+, SO_4^{2-} and HCO_3^-$ indicate that the groundwater is related partly with mineral-water reaction and partly with anthropogenic contamination, while the geothermal water is related with saline water. On the phase stability diagram, groundwater and thermal water mostly fall in the field of stability of kaolinite. This indicates that the ground and geothermal waters proceed with forming kaolinite. Factor and correlation analyses were carried out to simplify the physicochemical data into grouping some factors and to find interaction between them. Based on the Na-K, Na-K-Ca and Na-K-Ca-Mg geothermometers and silica geothermometers, the geothermal reservoir is estimated to have equilibrium temperature between 125${$\mid$circ}C$ and 160${$\mid$circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.123-131
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• 1999

To get the basic information for the improvement of the optimum levels of upland soil fertility and fertilizer application, the soil samples in two hundred fifteen site were collected from the major condiment vegetable cultivation areas such as red pepper, garlic and onion fields. Physico-chemical properties of the soil samples were investigated. Soil texture distribution of soil samples in red pepper, garlic and onion cultivation areas was in order of loam (L), sandy loam (SL), silt loam (SiL) and clay loam (CL) (35.4, 31.6, 14.9 and 7.0%, respectively). The average pH of soil in garlic and onion cultivation areas were over pH 6.0, whereas in red pepper was under pH 5.5. The frequency distribution of soil pH in total sampling sites were 58.7% in under pH 6.0 and 21.4% in below pH 5.0, in contrast to 10.3% in over pH 7.0. The organic matter contents were in the range of $20{\sim}30g\;kg^{-1}$, and the onion field soils was a little higher than those in red pepper or garlic. The available phosphate contents were in the range of $719{\sim}746mg\;kg^{-1}$ and were not different among in red pepper, garlic and onion. The frequency distribution of available phosphate in total sampling sites were found 62.8% of above $600mg\;kg^{-1}$, which was over the standard level for upland soil improvement, and then 22.3% was exceeded $1,000mg\;kg^{-1}$, especially. In the exchangeable cations, the K and Ca contents in garlic (1.27 and $9.11cmol\;kg^{-1}$) and onion (1.20 and $8.39cmol\;kg^{-1}$) were higher than in red pepper (0.96 and $5.87cmol\;kg^{-1}$), respectively. The Mg contents in garlic field soils ($2.17cmol\;kg^{-1}$) were higher than those in red pepper and onion (1.51 and $1.80cmol\;kg^{-1}$). This exchangeable K, Ca and Mg contents were higher than the standard level for upland soil improvement. The contents of microelement were ranged in $54.3{\sim}60.1mg\;kg^{-1}$ for Fe, $31.3{\sim}42.3mg\;kg^{-1}$ for Mn, $1.7{\sim}2.3mg\;kg^{-1}$ for Cu and $4.8{\sim}5.5mg\;kg^{-1}$ for Zn, respectively.

• Journal of Life Science
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• v.24 no.4
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• pp.403-410
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• 2014

This study was conducted in organic certification soil for the comparison of heavy metals, nutrients, and irrigated water standards to certify a farm. It was carried out in 811 paddy fields of organic rice (Oryza sativa L.) cultivated at Goseong-Gun. The amounts of 8 heavy metals, Cd, Cu, As, Hg, Pb, $Cr^{6+}$, Zn, and Ni were found to be 0.05, 14.5, 1.08, 0.92, 10.7, 1.34, 35.9, and 22.2 mg $kg^{-1}$ in regular sequence in the organic paddy soil, and they were 0.32, 13.6, 1.01, 0.03, 10.4, 0.91, 42.4 and 22.5 mg $kg^{-1}$ in the non-pesticide paddy soil. In comparing organic and non-pesticide paddy soil with respect to the chemical characteristics of the soil, the average pH and the amount of organic matter, available phosphate and available silicate were 5.88 and 27.6 g $kg^{-1}$, 134.5 mg $kg^{-1}$, and 165.3 mg $kg^{-1}$, while they were 5.78 and 32.1 g $kg^{-1}$, 107.7 mg $kg^{-1}$, and 175.2 mg $kg^{-1}$, respectively. The amount of exchangeable cation $K^+$, $Ca^{2+}$, and $Mn^{2+}$ were 0.25, 5.20, and 1.04 cmol+ $kg^{-1}$ in organic paddy soil, while they were 0.38, 5.13, and 1.19 cmol+ $kg^{-1}$ in non-pesticide paddy soil. The pH, DO, BOD, COD and SS conditions of the irrigated water used in the organic paddy soil were found to be 7.23, 8.40, 2.80, 1.86, and 2.58 mg $l^{-1}$ and the condition of irrigated water used in the non-pesticide paddy soil were found to be 7.65, 9.16, 2.25, 4.11, and 4.00 mg $l^{-1}$, respectively. Based on these findings, we suggest that environmentally-friendly certificates in Korea have to unify organic and non-pesticide agro-products in an organic standard in food policy and control because there is no difference between soil and irrigated water standards in the two certifications.