고출력 다이오드 레이저를 이용한 SKD11 표면 열처리 특성

최성대,정선환,양승철,김잠규 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

An experimental investigation with high power diode laser system was carried out to study the effect of surface heat treatment on the SKD11. The surface heat treatment characteristics of the laser beam were evaluated using hardness tests, optical microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy(EDS). Results indicated that the Hardness were changed by beam size, focal length, feed rates. The micro grain structure was observed retained austenite grain at hardened zone and globular cementite grain at fine grain zone and base metal zone by optical microscopy. The intensive X-ray diffraction patterns of (110)-(200)-(211) was detected on the surface and the hardened surface intensity level was bigger than the unhardened surface. The intensive X-ray diffraction patterns of (110)-(200)-(211) was detected hardened surface and the hardened surface distributed plenty of carbon density than metal zone.

DFSS에 의한 FPD용 높이 조절기구 설계

정선환,최성대,조규열 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-

This study was carried out to minimize the lifting force and to design the slim sized frame of a height adjustment mechanism. This unit is designed for the display devices in order to enhance the ergonomics for effective height adjustment as well as to achieve much slimmer frame for the pedestal. A tolerance analysis of 6 sigma was applied to achieve smooth lift at design stage not to change the tolerance specification of gap several times in a roller type of lifting mechanism at mass production stage. The specification of minimum gap and the target of production yield ratio were agreed with a quality team before tooling. A DFSS simulation on drawings had been done with reasonable tolerance and achievable standard deviation(σ) several times until the target spec of gap and yield ratio was met. Once tolerance and deviation(σ) were fixed tooling start was done successfully. A CAE method was applied to achieve a slim design. Design parameters were frozen when those parameters matched the reference strength data of standard model. Through those tolerance analysis and CAE simulation the number of tool modification was reduced and production yield ratio was raised up without arguing quality specification at production stage in the end.

UR 보조금 협정과 정보통신진흥기금의 개편방향

김동주,최선규 高麗大學校 産業開發硏究所 1995 産業開發硏究 Vol.4 No.-

MESOZOIC GARNITOIDS AND GOLD-SILVER MINERALIZATION IN KOREA

SEON-GYU CHOI,SANG JOON PAK,HONG JA SHIN 대한지질학회 2000 대한지질학회 학술대회 Vol.2000 No.

Petrology, geochronology and tectonic implications of Mesozoic high Ba–Sr granites in the Haemi area, Hongseong Belt, South Korea

Choi, Seon-Gyu,Rajesh, V. J.,Seo, Jieun,Park, Jung-Woo,Oh, Chang-Whan,Pak, Sang-Joon,Kim, Sung-Won Blackwell Publishing Asia 2009 The island arc Vol.18 No.2

<P>Abstract</P><P>Collision between the North and South China continental blocks began in the Korean peninsula during the Permian (290–260 Ma). The Haemi area in the Hongseong collision belt (proposed as the eastern extension in South Korea of the Dabie–Sulu collision zone of China) within the Gyeonggi Massif comprises post-collisional high Ba–Sr granite with intermediate enclaves that intruded into the Precambrian rocks. The intermediate enclaves have a shoshonitic affinity whereas the granite is a high-K calc-alkaline variety. The chondrite-normalized rare earth element (REE) pattern with relative enrichment of LREE over HREE and absence of a significant negative Eu anomaly typifies both enclaves and granite. Geochemical similarities of enclaves and granite are attributed to the involvement of enriched mantle sources in their genesis. However, dominant crustal components were involved in the formation of high Ba–Sr granites. A granite crystallization age of 233 ± 2 Ma was obtained from SHRIMP U–Pb zircon dating. This age is slightly younger than the Triassic collision event in the Hongseong Belt. Geochemical data, U–Pb zircon age, and regional tectonics indicate that the Haemi high Ba–Sr granite formed in a post-collisional tectonic environment. A Mesozoic post-collisional lithospheric delamination model can account for the genesis of high Ba–Sr granite in the Haemi area.</P>

Mineralogy and geochemistry of the Jeonheung and Oksan Pb-Zn-Cu deposits, Euiseong area

Seon gyu Choi(崔善奎),Jae ho Lee(李哉昊),Seong taek Yun(尹聖澤),Chil sup So(蘇七燮) 대한자원환경지질학회 1992 자원환경지질 Vol.25 No.4

慶北 義城지역 鉛-亞鉛-銅鑛床 (田興, 玉山 광산)은 慶尙盆地 白堊紀 퇴적암류내의 구조면을 충진한 熱水 석영-방해석 脈狀 鑛體로 구성된다. 鑛化작용은 구조적으로 석영-硫化物-硫鹽광물-적철석 정출기, barren 석영-형석 정출기, barren 방해석 정출기 등 3회로 구분된다. 鑛化 Ⅰ期의 鑛石광물은 황철석, 황동석, 섬아연석, 방연석 및 Pb-Ag-Bi-Sb계 硫鹽鑛物 등으로서 두 광산의 광물조성은 유사하지만, 유비철석, 자류철석, 테트라헤드라이트, 철을 다량 함유하는 (약 21 mole% FeS) 섬아연석 등은 玉山광산에서만이 산출된다. 변질대 絹雲母에 의한 K-Ar 연령은 약 62 Ma로서, 鑛化작용이 인근 金城山 칼데라 화산암류와 도처에 분포하는 산성암맥의 분출 및 관입 활동과 관련된 후기 白堊紀 화성활동의 산물이었음을 지시한다. 鑛化 Ⅰ期 광물정출은 0.7~6.3 wt.% NaCl 相當閻濃度를 갖는 鑛化流體로부터 >380°~240℃의 온도범위에서 진행되었고, 특히 銅광물은 대부분 >300℃의 고온에서 침전하였다. 流體包有物 연구에 의하면, Ⅰ기 鉛-亞鉛-銅광물의 침전은 沸騰ㆍ冷却ㆍ稀釋 등 비교적 복잡한 양식의 鑛液진화에 기인하였지만, 田興광산의 경우 차가운 天水의 流入에 따른 冷却 및 稀釋이 우세하였던 반면, 玉山광산의 경우는 沸騰이 우세하게 진행되었다. 鑛化流體의 沸騰에 근거한 鑛化작용시의 압력은 초기 약 210 bar에서 후기 약 80 bar에 이르며, 이는 熱水系가 靜岩壓이 우세한 환경에서 靜水壓이 우세한 환경으로 전이되었음을 지시하여 주고 따라서 鑛化深度는 약 900 m로 추정된다. 硫化物의 硫黃同位元素 조성 (2.9~9.6‰)에 근거한 초기 熱水流體의 全유황동위원소값 (δ³⁴S∑S)은 약 8.6‰이며, 이는 深部 火成源의 유황이 퇴적암류내 sulfate (?)와 다소 혼합되었음을 나타내는 것으로 사료된다. 한편, 수소 및 산소동위원소 조성은 熱水系 내의 물이 대부분 天水로부터 기원하였음을 지시한다. 鑛物熱力學적 고찰 결과, Ⅰ기 鑛化流體의 온도 및 硫黃分壓의 변화는 두 광산에서 다소 상이하였다. 즉, 日興광산의 경우 온도 감소와 더불어 硫黃盆壓은 황철석-적철석-자철석의 공존선을 따라 지속적으로 감소하였으나, 玉山광산의 경우는 초기 황철석-자류철석 공존환경으로부터 후기 황철석-적철석-자철석의 공존환경으로 전이하였다. 한편, 차고 酸化 상태인 天水가 鑛液 중에 混入됨에 따라 광액의 酸素盆壓은 점차 증가하였다. 銅광물의 침전은 주로 鑛化流體의 냉각에 따른 銅鹽化複合體(CuCl°)의 용해도 감소에 기인하였으리라 고려된다. 이러한 냉각 작용은 田興광산의 경우 주로 天水混入에 따른 결과였지만, 玉山광산의 경우는 주로 鑛化流體의 沸騰에 기인하였다. Lead-zinc-copper deposits of the Jeonheung and the Oksan mines around Euiseong area occur as hydrothermal quartz and calcite veins that crosscut Cretaceous sedimentary rocks of the Gyeongsang Basin. The mineralization occurred in three distinct stages (Ⅰ, Ⅱ, and Ⅲ): (Ⅰ) quartz-sulfides-sulfosalts-hematite mineralization stage; (Ⅱ) barren quartz-fluorite stage; and (Ⅲ) barren calcite stage. Stage Ⅰ ore minerals comprise pyrite, chalcopyrite, sphalerite, galena and Pb-Ag-Bi-Sb sulfosalts. Mineralogies of the two mines are different, and arsenopyrite, pyrrhotite, tetrahedrite and iron-rich (up to 21 mole % FeS) sphalerite are restricted to the Oksan mine. A K-Ar radiometric dating for sericite indicates that the Pb-Zn-Cu deposits of the Euiseong area were formed during late Cretaceous age (62.3±2.8 Ma), likely associated with a subvolcanic activity related to the volcanic complex in the nearby Geumseongsan Caldera and the ubiquitous felsite dykes. Stage Ⅰ mineralization occurred at temperatures between >380° and 240℃ from fluids with salinities between 6.3 and 0.7 equiv. wt. % NaCl. The chalcopyrite deposition occurred mostly at higher temperatures of >300℃. Fluid inclusion data indicate that the Pb-Zn-Cu ore mineralization resulted from a complex history of boiling, cooling and dilution of ore fluids. The mineralization at Jeonheung resulted mainly from cooling and dilution by an influx of cooler meteoric waters, whereas the mineralization at Oksan was largely due to fluid boiling. Evidence of fluid boiling suggests that pressures decreased from about 210 bars to 80 bars. This corresponds to a depth of about 900 m in a hydrothermal system that changed from lithostatic (closed) toward hydrostatic (open) conditions. Sulfur isotope compositions of sulfide minerals (δ³⁴S=2.9~9.6 per mil) indicate that the δ³⁴S∑S value of ore fluids was ○8.6 per mil. This δ³⁴S∑S value is likely consistent with an igneous sulfur mixed with sulfates (?) in surrounding sedimentary rocks. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values. Equilibrium thermodynamic interpretation indicates that the temperature versus fs₂ variation of stage Ⅰ ore fluids differed between the two mines as follows: the fs₂ of ore fluids at Jeonheung changed with decreasing temperature constantly near the pyrite-hematite-magnetite sulfidation curve, whereas those at Oksan changed from the pyrite-pyrrhotite sulfidation state towards the pyrite-hematite-magnetite state. The shift in minerals precipitated during stage Ⅰ also reflects a concomitant fo₂ increase, probably due to mixing of ore fluids with cooler, more oxidizing meteoric waters. Thermodynamic consideration of copper solubility suggests that the ore-forming fluids cooled through boiling at Oksan and mixing with less-evolved meteoric waters at Jeonheung, and that this cooling was the main cause of copper deposition through destabilization of copper chloride complexes.

Mesozoic Geodynamics and Epithermal Mineralization in Korea

Seon-Gyu Choi,In-Chang Ryu,Soo-Meen Wee 대한지질학회 2003 대한지질학회 학술대회 Vol.2003 No.

忠淸道 東北部 泰昌ㆍ寶蓮, 金旺 鑛山의 金銀鑛化作用

Seon Gyu Choi(崔善奎),No Young Park(朴魯榮),Sung Won Park(朴性元) 대한자원환경지질학회 1986 자원환경지질 Vol.19 No.5

A number of auriferous veins occur in the Precambrian metamorphic terrain from Chungju to Mugeug district. These gold(-silver) deposits consist mainly of the fissure-filling quartz veins intruding the Precambrian gneiss or schist and Jurassic or Cretaceous granite. These gold (-silver) deposits can be divided into two mineralization epochs, (a) gold-rich veins related to Daebo igneous activity, and (b) gold-silver veins related to Bulgugsa igneous activity. These two groups of ore deposits with different generation can be characterized by the mode of occurrence of ore vein and the ore mineral associations. The auriferous quartz veins of Taechang and Boryeon mines associated with late Jurassic igneous activity are massive in character, and show the simple mineral assemblages and low Ag/Au ratio in the ores, representing a single mineralization system. The ore minerals are predominantly quartz containing minor or trace amonts of pyrrhotite, sphalerite, galena, pyrite, chalcopyrite and electrum. Electrum is closely associated with pyrrhotite and has chemical compositions from 61.4 to 78.5 atomic % Au. Fluid inclusion data suggest that ore minerals were deposited at temperatures between 238 and 390℃ from CO₂-rich fluids. The gold and/or silver-bearing quartz veins of Geumwang mine related to middle Cretaceous igneous activity are characterized by the multistage history, diverse mineral assemblages with high Ag/Au ratio in the ores. The ores of Geumwang mine have two contrasting mineral assemblages (1) pyrite+galena+sphalerite+arsenopyrite+electrum+argentite, representing the higher gold mineralization, and (2) pyrite+chalcopyrite+galena+sphalerite+arsenopyrite+silver sulfosalts+electrum+native silver+argentite, representing the higher silver mineralization. Electrum is closely associated with pyrite and has chemical compositions from 11.2 to 49.9 atomic % Au. The depositional environment during the higher gold mineralization can be estimated as the range of both temperature and sulfur fugacity, T=200~300℃, logf (S₂)=10⁻¹⁰~10⁻¹⁵. The higher silver mineralization may be interpreted to have formed a range of falling temperature (150~200℃) and low sulfur fugacity(10⁻¹⁵~10⁻¹⁸). These temperature data are consistent with homogenization temperatures of fluld inclusions in quartz. Thus, the gold veins related to the Daebo igneous activity may be formed by the environment of higher temperature and pressure than the gold-silver veins associated with the Bulgugsa igneous activity.

忠淸道 一圓의 金ㆍ銀鑛床에 대한 鑛物學的 硏究

Seon Gyu Choi(崔善奎),No Young Park(朴魯榮),Sei Sun Hong(洪世善) 대한자원환경지질학회 1988 자원환경지질 Vol.21 No.3

A large number of gold and/or silver-bearing quartz veins occur in or near Mesozoic granite batholith elongated in a NE-SW direction within the Chungcheong Province. Precambrian schists and gneisses, and Jurassic and Cretaceous granitic rocks serve as hosts for gold and/or silver deposits. On the basis of Ag/Au total production and ore grade ratio, 15 mines may be divided into three major groups: gold-dominant deposits, gold-silver deposits, and silver-dominant deposits. The chemical composition of electrum from skarn deposit (Geodo mine), alaskite-type deposit (Geumjeong mine) and 15 vein deposits was summarized. It was found that the Au content of electrum for vein deposits ranging from 5.2 to 86.5 is lower than that for skarn and alaskite deposits. Among 15 vein deposits, the composition of electrum associated with pyrrhotite is relatively high and has a narrow range of 40.8 to 86.5 atomic % Au, but the Au content of electrum with pyrite is in range of 5.2 to 82.8 atomic %, and is clearly lower than that with pyrrhotite. The grouping of ages for these mines indicates that gold and/or silver mineralizations occurred during two periods in the Mesozoic. Daebo igneous activities are restricted to gold mineralization in the range of 158 to 133 Ma, whereas Bulgugsa igneous activities are related to gold and/or silver mineralization ranging from 108 to 71 Ma. Generally speaking, Jurassic gold-dominant veins have many common characteristics; notably prominent association with pegmatites, simply massive vein morphology, high fineness in the ore concentrates, rarity of silver minerals, and a distinctively simple mineralogy, including sphalerite, galena, chalcopyrite, pyrrhotite and/or pyrite. Although individual deposits exhibit widely differing diversity, Cretaceous gold-silver and silver-dominant veins are characterized by features such as complex vein, low to medium fineness in the ore concentrates and abundance of silver minerals including Ag sulfosalts, Ag sulfides, Ag tellurides and native silver.

忠淸北道 永同地域 金銀鑛床의 金銀鑛化作用에 관한 硏究

Seon Gyu Choi(崔善奎),Se Jung Chi(池世定),Sung Won Park(朴性元) 대한자원환경지질학회 1988 자원환경지질 Vol.21 No.4

Most of the gold (-silver) vein deposits at Yeongdong District are mainly distributed in the precambrian metamorphic rocks. Based on the Ag/Au total production and ore grade ratios, the chemical composition of electrum and the associated sulfides, the gold(-silver) deposits at Yeongdong District may be classified into 4 classes: pyrrhotite - type gold deposits( I), pyrite - type gold deposits (IT A; massive vein), pyrite - type gold deposits (II B; nonmassive vein) and argentite - type gold - silver deposits(III). The chemical study on electrum(including native gold) revealed that Au content (2.8 to 92.4 atomic%) of electrums varies very widely for different classes of deposits. The Au content of electrum associated with pyrrhotite (Class I), ranging from 47.1 to 92.4 atomic% Au, is clearly higher than that associated with pyrite (Classes IIA, IIB and III). In contrast, classes I, II, and III deposits do not show clear differences in Au content of electrum. In general, pyrrhotite - type gold deposits(I) are characterized by features such as simply massive vein morphology, low values in the Ag/Au total production and ore grade ratios, the absence or rarity of silver - bearing minerals except electrum, and distinctively simple mineralogy. Although the geological and mineralogical features and vein morphology of pyrite - type gold deposits(IIA)are very similar to those of pyrrhotite - type gold deposits (I), Class II A deposits reveal significant differences in the associated iron sulfide (i. e. pyrite) with electrum and Au content of electrum. The Ag/Au total production and ore grade ratios from Class II A deposits are relatively slightly higher than those from Class I deposits. Pyrite - type gold deposits(II B) and argentite - type gold - silver deposits (III) have many common features; complex vein morphology, medium to high values in the Ag/Au total production and ore grade ratios and the associated iron sulfide (i. e. pyrite). In contrast to Class II B deposits, Class III deposits have significantly high Ag/Au total production and ore grade ratios. It indicates distinct difference in the abundance of silver minerals (i. e. native silver and argentite). The fluid inclusion analyses and mineralogical data of electrum tarnish method indicate that the gold mineralization of Classes I and II A deposits was deposited at temperatures between 230° and 370℃, whereas the gold (-silver) mineralization of Classes ITB and ill formed from the temperature range of 150°-290℃. Therefore, Classes I and IT A deposits have been formed at higher temperature condition and/or deeper positions than Classes IIB and III.