• Economic and Environmental Geology
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• v.51 no.6
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• pp.521-529
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• 2018

This study was conducted to investigate the natural origin of fluorine contained in the rocks within the Eulwangsan area via petrological and mineralogical analyses. The main geology of the Yongyudo Eulwangsan area is Triassic biotite granite. Biotite granite and mylonite are the major rock types containing fluorine at high levels (up to 1,700 and 2,400 mg/kg for biotite granite and mylonite, respectively). In the case of the biotite granite, a high concentration of fluorine can be contributed to fluorite, and the results of microscopic analyses show that the fluorite was observed as small veinlets filling cleavages and micro-fractures within alkali-feldspars and plagioclases, or observed together with quartz in ore veins, indicating the secondary formation of fluorite by hydrothermal fluids. In mylonite, on the other hand, a high fluorine concentration is attributable to sericite. Microscopic analyses revealed that the boundary between sericite and surrounding quartz was not clear, the sericite occurred filling the micro-fractures of quartz and encapsulating small quartz cataclasts. These results indicate that the sericite was also formed as a result of hydrothermal alteration. Consequently, it is speculated that the high fluorine level in the rocks of the Eulwangsan area of Yongyudo is of natural origin due to hydrothermal processes.

• Journal of the Korean association of regional geographers
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• v.11 no.4
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• pp.440-452
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• 2005

The granites in the Gyeongju area are represented by the Namsan granites and the Tohamsan granodiorites. In this study I examined the geomorphological and geological characteristics of the granite landforms in the Gyeongju area. Joint, tor and corestones are most identifiable geomorphological and geological structure in the study areas. Tor in the Namsan granites is well developed and mainly composed of cubic corestones. Petrographical features of the stones used for the stone-built cultural properties are compared with those of the granites cropped out nearby. Additionally radiogenic element contents (K, Th, U) were acquired for comparison by gamma-ray spectrometer analysis. Most stones from the stone-built cultural properties in the Bulguksa Temple are very similar to the Namsan granites in terms of petrography, radiogenic elements. On the contrary almost all stones from the Seokguram Grotto share common petrographical, physical and chemical characteristics with the Tohamsan granodiorites. Therefore it can be suggested that the stones in the Bulguksa Temple were supplied from Namsan, and that the stones in the Seokgurarn Grotto were collected at nearby Tohamsan.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.37-37
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• 2011

열가소성 고분자 물질인 PET[poly(ethylene terephthalate)]는 섬유 및 필름, 음료병 등에 널리 사용되는 대표적인 범용 소재이며, 전체 PET 제조업은 2013년 약 200억불에 달할 것으로 예상되는 큰 시장이다. 최근 급격한 산업화에 따른 전 세계적인 환경오염의 심각성이 부각되면서 기업들의 환경 친화적인 제조 활동 및 생산 프로세스의 개선이 요구되고 있다. 현재 폴리에스테르 수지를 제조하기 위해 국내외 업체에서 가장 널리 사용 되고 있는 중합촉매는 중금속 원소인 고순도 삼산화안티몬($Sb_2O_3$)이며 통상 중합공정 중에 150~300ppm의 촉매가 사용된다. 세계보건기구(WHO)의 국제암연구기관(IARC)에서는 안티몬을 인체 발암성이 있는 물질로 분류 하여 현재 유럽을 중심으로 안티몬 사용을 제한하는 환경 규제가 가속화 되고 있다. 폴리에스테르 수지 제조 공정중 안티몬 촉매를 사용할 경우 정련, 염색, 알칼리 감량시 중금속(안티몬)검출에 따른 수질 오염 및 폐수처리비용이 증가하게 되며 대량의 중합촉매 사용에 따른 이물 증가로 작업성 및 품질 문제가 상존하게 된다. 따라서 이러한 제조 공정중의 고위험성 물질을 대체할 친환경, 고부가가치 신규 무독성 PET 소재 및 제품이 각광을 받게 될 것이다. 이번 연구에서는 티타늄계(Ti-based) 무독성 촉매를 이용하여 PET 중합을 실시한 Sb-free PET원단의 염색특성을 알아보는 것으로 분산염료 3종 (Red, Yellow, Blue)으로 염색이 완료된 원단을 spectrophotometer 를 이용하여 L, a b값과 K/S값으로 측정하였다. 동일한 염색 조건을 위해 두 종류의 원단을 하나의 실린더에서 기존 PET 염색과 동일한 조건으로 염색을 실시하였으며 실험 결과 전반적으로 기존 PET와 유사한 염색 특성을 보였다. 염색견뢰도 평가에서도 Sb-free PET원단과 기존 PET원단의 세탁 견뢰도, 마찰 견뢰도, 일광 견뢰도를 비교 했을 시 두 원단 모두 4~5급으로 우수한 견뢰도를 나타내었다.

• The Journal of the Petrological Society of Korea
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• v.8 no.2
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• pp.81-91
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• 1999

The area of the study is located in Ogcheon district, middle part of Ogcheon Fold Belt. The area is covered by metasedimentary rocks of Ogcheon Supergroup at northern, eastern and southern part. Jurassic Ogcheon granite which intruded into Ogcheon Supergroup at central part, was intruded by Cretaceous quartz porphyry at western part. The granite consists of quartz, plagioclase, alkali feldspar, biotite, sphene, apatite, epidote, opaque and so on. It is generally characterized by grey to light grey, medium-grained, mafic enclave and partly weak foliation. In terms of geochmical compositions, the granite is felsic, peraluminous, subalkaline and calc-alkaline, and it was differentiated from single granitic magma. It shows parallel LREE enrichment and HREE depletion patterns with 0.84 Eu negative anomaly, which has REE variation trend and anomaly value similar to Jurassic granites in Korea. From charactristics of petrology, mineralogy and geochmistry, it may be interpreted that the Ogcheon granite body was derived from melting of I-type crustal material related to syn-collisional tectonic setting and emplaced more or less rapidly into the Ogcheon Supergroup.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.155-157
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• 2022

담낭용종은 담낭암의 원인일 수 있다. 담낭용종의 잘 알려진 위험요소는 대사증후군, 젊은 나이, 이상지질혈증 등이다. 제주도는 한반도에서 약 80km 떨어져 있으며 한라산을 중심으로 두 개의 행정구역(제주시와 서귀포시)으로 나뉘어 있다. 국제공항과 국제항구는 유일하게 제주시에만 위치해 있다. 또한 제주시에는 서귀포시보다 기업체와 학교의 수가 더 많다. 식이 및 알코올 소비는 두 지역 간에 다르며 이러한 요인이 담낭용종 유병률에 영향을 미칠 것이다. 따라서 이 연구의 목적은 두 지역 거주민들의 담낭용종 유병률을 조사하고 담낭용종과 관련된 다양한 요인들을 비교해보고자 하였다. 본 연구는 2009년 1월부터 2019년 12월까지 제주대학교병원 단일 건강검진센터를 방문한 21,734명을 대상으로 하였다. 담낭용종 유병률과 관련된 요인을 제주시 거주민과 서귀포시 거주민 두 집단으로 나누어 조사하였다. 담낭용종 유병률은 제주시가 10.1%, 서귀포시가 9.2% (P = 0.039)였다. 평균 연령과 고위험 음주자의 비율은 서귀포시에서 더 높았다. 평균 체질량지수와 공복혈당, 총콜레스테롤, 저밀도지질단백질-콜레스테롤, 아스파르테이트아미노전이효소, 감마-글루타밀전이효소, 알칼리인산분해효소 수치는 제주시에서 낮게 나타났다. 이 연구에서 담낭용종 유병률은 제주도의 두 지역 간에 유의한 차이가 있었다. 연령과 알코올 소비는 이러한 차이에 기여하는 주요 요인이 될 수 있다.

• Economic and Environmental Geology
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• v.34 no.4
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• pp.395-415
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• 2001

In the Singok area, western part of Chungcheongnam-Do, two ultramafic ma~ses, Singok mass and Kaewol mass, occur as isolated lenticular bodies in the Precambrian Kyeonggi gneiss complex. The masses extend for several hundred meter to NNE direction, parallel to the main fault line of this area. The rocks are dunite and harzburgite, but partially and absolutely serpentinized. They dominantly show porphyroclastic and recrystallized textures with equigranular-mosaic and protogranular textures. In spite of differences among the alteration and metamorphism, the ultramafic masses are characterized by varying amounts of high fosteritic olivine ($Fo_{0.88-0.93}$), magnesian pyroxene ($En_{0.93-0.97}$), and tremolitic to tschermakitic hornblende with minor spinel, serpentine, chlorite, calcite, magnetite, phlogopite and talc. It is compared with adjacent gneiss complex containing amphibole, biotite, plagioclase, alkali-feldspar and quartz. Geochemically, these rocks show high magnesium number (Mg>90.38), and transitional element (Ni=595-2480, Cr==IOlO-4400, Co=36-120 ppm), low alkali element ($Na_{2}O$<0.3, $K_{2}O$<0.11, $Al_{2}O_3$<2.95 wt%) and depleted incompatible element contents, which is compared with adjacent rocks (Mg < 83.69, $Na_{2}O$=1.02-3.42 wt%, $K_{2}O$=O.67-5.65 wt%, $Al_{2}O_3$=9.15-16.86 wt%, Ni < 435 ppm, Cr < 1440 ppm, Co<59 ppm, enriched incompatible element contents). Overall characteristics of ultramafic rocks from the Singok and Kaewol masses are similar to the those of adjacent ultramafic bodies in Chungnam with worldwide orogenic related Alpine type ultramalic rocks. Calculated geothermometries suggest that the ultramafic rocks have experienced metamorphism in the condition ranging from the greenschist facies to granulite facies.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.93-113
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• 2008

This study presents petrochemistry and $^{40}Ar/^{39}Ar$ absolute ages of subsurface volcanic rock cores from twenty(20) boreholes in the eastern lowland (altitude loom below) of Jeju Island, Handeong-Jongdal-Udo-Susan-Samdal-Hacheon areas, and discusses topography and volcanism in the area. The subsurface volcanic rock cores are mainly basalts in composition with minor tholeiitic andesites and basaltic trachyandesites. Sequences of intercalated tholeiitic, transitional and alkalic lavas suggest that tholeiitic and transitional to alkalic lavas must have erupted contemporaneously. Especially, occurrences of trachybasalts and basaltic trachyandesites at the bases in the area imply that the volcanism in the area was initiated with slightly differentiated alkaline magma activity. The $^{40}Ar/^{39}Ar$ absolute ages of the subsurface volcanic rock cores range from $526{\pm}23ka\;to\;38{\pm}4Ka$. The lava-forming Hawaiian volcanic activities of the eastern lowland can be divided into five sequences on the basis of sediment distribution, whole rock geochemistry and $^{40}Ar/^{39}Ar$ absolute ages of the subsurface volcanic rock cores; stage I-U$(550{\sim}400Ka)$, stage II$(400{\sim}300Ka)$ and stage III$(300{\sim}200Ka)$ during syn-depositional stage of Seoguipo Formation, and stage IV$(200{\sim}100Ka)$ and stage V(younger than 100Ka) during post-depositional stage. In the eastern lowland of Jeju Island, compositional variations and local occurrences of the subsurface volcanic rocks as well as existences of various intercalated sediment layers (including hydrovolcanogenic clasts) suggest that the volcanism must have continued for long time intermittently and that the land has been progressively glowed from inland to coast by volcanic activities and sedimentation. It reveals that the subsurface volcanic rocks in the eastern lowland of Jeju Island must have erupted during relatively younger than 200Ka of stages IV and V. The results of this study are partly in contrast with those of previous studies. This study stresses the need that previous reported volcanic activities in Jeju Island based on K-Ar ages of volcanic rocks should be carefully reviewed, and that stratigraphic correlation from boreholes should be conducted by quantitative criteria combined with petrography and petrochemstry as well as radiometric studies of volcanic rock cores.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.113-127
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• 2005

Cretaceous intrusive and extrusive rocks are widely distributed in the southwestern part of the Korean peninsula, possibly the result of intensive magmatism which occurred in response to subduction of the western proto-Pacific plate beneath the north-eastern part of the Eurasian plate. Geochemical and petrological study on the Cretaceous granitic rocks were carried out in order to constrain the petrogenesis of the granitic magma and to establish the paleotectonic environment of the area. Whole rock chemical data of the granitic rocks from the study area indicate that the all the rocks have characteristics of calc-alkaline series in the subalkaline field. The overall geochemical features show systematic variations in each granitic body, but the source materials of each granitic body are thought to have been different in their chemical composition. Higher values of $Fe_2O_3/FeO$ of the granitic rocks in the western area suggest that the granitoids had been solidified under highly oxidizing environment. The granitic bodies in the eastern area also show higher contents of Li, Ni, Co, Sr, Cr, Sc and lower Rb and Nb compared to the those of the western area. Chondrite normalized REE patterns show generally enriched LREE and strong negative Eu anomalies in the western wet while slight to flat Eu anomalies in the east-ern area. The REE and $(La/Lu)_{CN}$ of the granites are $60{\~}499ppm$ and $8.9{\~}66$ correspond to the range of the continental margin granite. On the ANK vs. ACNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type, VAG and syn-collision granite. Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at continental margin during the subduction of proto-Pacific plate.

• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.555-566
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• 2006

Major, trace and rare earth elements data of the Cretaceous Jindong granitic rocks were investigated in order to constrain the magma source characteristics and to establish the paleotectonic environment of the southwestern part of the Gyeongsang Basin. Geochemical signatures of the granitic rocks from the study area indicate that all of the rocks have characteristics of calc-alkaline series in the subalkaline field, and progressively shift from metaluminous to peraluminous with differentiation. In the variation diagrams, the overall geochemical features of the granites show systematic variations in major and trace elements. Chondrite normalized REE patterns show generally enriched LREE((La/Yb)c=4.2-12.8) and slight negative to flat Eu anomalies. Rb-Sr isotope data of the Jindong granites show that the whole rock age and Sr initial ratio are $114.6{\pm}9.1Ma$ and 0.70457, respectively. The Sr initial ratio of the Jindong granites is very similar to those of the Creataceous granites from Masan, Kimhae and Busan area($^{87}Sr/^{86}Sr=0.7049-0.707$). These results suggest that the magma have the mantle signature and intruded into the area during the early Cretaceous age. The Jindong granites have higher $Al_{2}O_{3},\;Na_{2}O$, Sr and lower $K_{2}O$, Y concentrations compared with typical calc-alkaline granitic rocks. These adakitic signatures are similar to those of adakitic pluton on Kyushu Island, southwest Japan arc. On the ANK vs. ACNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type, VAG granite. Interpretations of the geochemical characteristics of the granitic rocks favor their emplacement at continental margin during the subduction of Izanagi plate.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.201-213
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• 1998

From the Jungwon and Munkyeong areas which are among the famous producers of the carbonate-type groundwaters in Korea, various kinds of natural waters (deep groundwater, shallow groundwater and surface water) were collected between 1996 and 1997 and were studied for hydrogeochemical and environmental isotope (${\delta}^{34}S_{so4}$, ${\delta}^{18}O$, ${\delta}D$)systematics. Two types of deep groundwaters (carbonate type and alkali type) occur together in the two areas, and each shows distinct hydrogeochemical and environmental isotope characteristics. The carbonate type waters show the hydrochemical feature of the 'calcium(-sodium)-bicarbonate(-sulfate) type', whereas the alkali type water of the 'sodium-bicarbonate type'. The former type waters are characterized by lower pH, higher Eh, and higher amounts of dissolved ions (especialJy, $Ca^{2+}$, $Na^{+}$, $Mg^{2+}$, $HCO_3{^-}$ and $SO_4{^{2-}}$). Two types of deep groundwaters are all saturated or supersaturated with respect to calcite. Two types of deep groundwaters were both derived from pre-thermonuclear (about more than 40 years old) meteoric waters (with lighter 0 and H isotope data than younger waters, i.e., shallow cold groundwaters and surface waters) which evolved through prolonged water-rock interaction. Based on the geologic setting, water chemistry, and environmental isotope data, however, each of these two different types of deep groundwaters represents distinct hydrologic and hydrogeochemical evolution at depths. The carbonate type groundwaters were formed through mixing with acidic waters that were derived from dissolution of pyrites in hydrothermal vein ores (for the Jungwon area water) or in anthracite coal beds (for the Munkyeong area water). If the deeply percolating meteoric waters did not meet pyrites during the circulation, only the alkali type groundwaters would form. This hydrologic and hydrogeochemical model may be successfully applied to the other carbonate type groundwaters in Korea.