• 자원환경지질
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• 제21권3호
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• pp.287-307
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• 1988

The Cheongju gold-silver mine is located at approximately $36^{\circ}28^{\prime}$north latitude and $127^{\circ}31^{\prime}$ east longitude in the Cheongju City of the Chung cheong bug Do, South Korea. Gold-Silver bearing hydrothermal quartz veins, occur in Cheongju Granit of Jurassic age. K-Ar isotope data for sericite in quartz vein indicate that the Au-Ag mineralization took place in early Cretaceous ($97.5{\pm}2.18$ MA. Park, et ai, 1986). Three stage of mineralization recognized anre, from early to later, (I) Sulide stage: pyrite, arsenopyrite, pyrrhotite (Hpo), sphalerite, chalcopyrite, electrum and quartz (II) Electrum stage: pyrite, sphalerite, galena, chalcopyrite, electrum and quartz. (III) Silver mineral stage: pyrite, marcasite, pyrrhotite (Mpo), sphalerite, galena, electrum, native silver argentite, fluorite, calcite and quartz. In this paper, mode of occurrences and chemical compositions of electum and native silver have been investigated by means of microscope and EPMA. Electron probe microanalysis shows that an individual grain of electrum is almost homogeneous in composition. Silver content of electrum ranges from 44.7-67.1 atom.%. Gold content of native silver ranges below 0.2 atom. %. Vicker's hardness number (VHN) of electrum and native silver ranges $78.2-81.8kg/mm^{2}$ respectively. The filling temperature of fluid inclusions in quartz ranges from $130-280^{\circ}C$. On the basis of arsenpyrite geothemometer, the equilibrium temperature and sulfur fugacity of the pyrite-arsenopyrite-pyrrhotite(Hpo) assemblage is assumed to be in ange from $300-310^{\circ}C$ and $10^{-10}$ to $10^{-11}$ atm. The estimated ore reserviors on Cheongju mine area are calculated to 8000 T/M, averaing 8.6g/t Au, 27.8 g/t Ag, 1.25% Pb, l.65% Zn.

• Composites Research
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• 제32권3호
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• pp.163-169
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• 2019

본 연구에서 우리는 자유 라디칼 중합에 기반한 열가소성 고분자의 동적 분자동역학 중합 알고리즘을 이용하여 95%의 변환률을 갖는 PMMA의 고분자 모델을 구성하였다. 본 알고리즘에서는 계산 수행에 필요한 시간을 줄이기 위해 PCFF 포텐셜 함수의 결합 항들 TraPPE-UA 포텐셜 함수의 비결합 항을 조합한 united-atom level의 coarse-grained 포텐셜 함수를 도입하였다. 자유 라디칼 중합 시뮬레이션을 통해 생성된 각 사슬을 분석하여 고분자의 분자량 분포와 평균 분자량을 계산하였고, 고분자의 분자량은 초기 상태에 존재하는 개시제 라디칼의 수를 이용하여 조절하였으며, 유리전이온도, 기계적 물성에 미치는 분자량의 효과에 대해 연구되었다.

• 한국산업정보학회논문지
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• 제27권6호
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• pp.95-103
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• 2022

원자력발전소의 중대사고 발생 시 신속하고 정확하게 사고 상황을 파악해야 하며, 이러한 사고진단 정보를 획득했을 때 적절한 사고관리 및 대응을 수행할 수 있다. 본 연구에서는 국가원자력 재난관리 시스템인 AtomCARE (Computerized technical Advisory system for a Radiological Emergency)로 전송되는 주요 발전소 정보로부터 중대사고 상황을 진단하는데 있어 딥러닝 기술의 접목을 고려하였다. 이를 위하여 주요 시나리오를 선정하고 사고 진행에 따른 상세 시나리오에 대하여 중대사고 해석 코드인 MAAP5 다량 계산을 통한 학습 DB를 구축하였다. 그리고 이 DB의 학습을 통하여 주요 발전소 정보로부터 중대사고 상세 시나리오를 분류할 수 있는, 즉 중대사고 상황을 진단할 수 있는 기술을 개발하였다. 또한 블라인드 테스트와 주성분분석을 통한 검증을 수행하였다. 본 연구에서 개발한 기술은 향후 전체 중대사고 시나리오로 확장 및 적용 가능할 것으로 판단되며 신속하고 정확한 사고진단의 기반기술로 활용 가치가 높을 것으로 기대된다.

• 공업화학
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• 제8권4호
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• pp.582-588
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• 1997

고체산 촉매인 헤테로폴리산 촉매를 이용하여 대기오염 방지를 위한 옥탄가 향상제인 TAME, ETBE 및 MTBE 합성반응에 대한 실험을 고정층 상압유통식 반응장치에서 수행하였다. 일반적으로 TAME, ETBE 및 MTBE 합성반응에서 헤테로폴리산에 hetero원자와 poly원자를 치환시켜 비교한 결과, 배위된 poly원자가 W, hetero원자가 Si인 $H_4SiW_{12}O_{40}$ 촉매의 활성이 가장 우수하였고, 또한 치환된 금속에 따라 촉매의 활성이 달랐으며 이는 촉매의 산성질과 관련이 있음을 알 수 있었다. 헤테로폴리산 촉매를 이용한 합성반응에서 TAME 경우는 $FeHPW_{12}O_{40}$과 $K_3PM_{o12}O_{40}$이 비교적 활성이 좋았으나, ETBE나 MTBE 경우에 비해서는 다소 활성이 낮았다. 그리하여 본 연구에서는 활성이 좋은 헤테로폴리산 촉매들을 선정하여 각각에 대하여 1:1로 다음과 같이 혼합하여 $H_4SiW_{12}O_{40}$ : $Sr_2SiW_{12}O_{40}$, $H_4SiW_{12}O_{40}$ : $NaH_2PW_{12}O_{40}$, $Fe_{1.5}PW_{12}O_{40}$ : $Mg_2SiW_{12}O_{40}$ 및 $Mg_2SiW_{12}O_{40}$ : $Ba_2SiW_{12}O_{40}$ 실험한 결과, 혼합촉매들이 각각의 단일성분 촉매때보다 TBA의 전화율과 ETBE나 MTBE의 선택율이 더욱 향상되었음을 알 수 있었다.

• 한국자기학회지
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• 제25권6호
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• pp.175-179
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• 2015

덩치상태에서 반쪽금속성을 나타내는 $(AlP)_1/(CrP)_1$ 초격자계에서 (001) 표면의 자성과 반쪽금속성에 대해 FLAPW (Full-potential Liniarized Augmented Plane Wave) 방법을 이용하여 연구하였다. (001) 표면이 나타나는 Al(S)-, Cr(S)-, P(S)Al(S-1)- 및 P(S)Cr(S-1)-term 계 등 모두 네 가지 표면계를 고려하였다. 계산결과 Cr(S)-term 계만 정수배의 보어마그네톤의 자기모멘트를 가져 표면에서 반쪽금속성이 유지됨을 알았다. 이 계에서 표면 Cr 원자의 자기모멘트는 띠좁힘과 스핀분리의 증가 등의 표면효과로 인해 덩치상태에 비해 증가한 $3.02{\mu}_B$였다. P(S)Al(S-1)-term 계에서 표면 P(S)층의 상태밀도는 $p_z$ 상태의 국소화로 인해 매우 예리한 표면상태의 봉우리를 보여 주었으며, P(S)Cr(S-1)-term의 경우 P(S)층과 Cr(S-1)층 사이에 큰 혼합이 존재하였고, 그 결과 P(S)층의 자기모멘트는 $-0.33{\mu}_B$이었다.

• Bulletin of the Korean Chemical Society
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• 제23권3호
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• pp.395-399
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• 2002

The voltammetric behavior of spontaneously adsorbing Mo layers on Pt(111) and Pt(100) electrodes has been studied to estimate the number of electrons involved in the electrochemical processes of spontaneously adsorbed Mo and the number of the bloc ked Pt sites for hydrogen adsorption. On Pt(111) and Pt(100) surfaces, the spontaneously adsorbed Mo layers showed redox peaks at 0.10 V and 0.15 V, respectively, and continuous current-potential waves in the conventional hydrogen region. Since the potential range of the Mo redox processes on both surfaces overlapped partially with the potential range of hydrogen adsorption, the variation in the ratio of the total charge of Mo and H ($Q_H$ +$Q_{MO}$) to the hydrogen charge of clean Pt electrode ($Q_H^0$) was analyzed. From the analysis, six electrons were estimated to be involved in the electrochemical processes of the spontaneously adsorbed Mo, and four Pt sites for hydrogen adsorption were calculated to be blocked by one adsorbed Mo atom. Based on these figures and the pH dependence of the Mo redox processes, we have proposed an electrochemical equation for the spontaneously adsorbed Mo. This electrochemical equation led us to conclude that the saturation coverage of the spontaneously adsorbed Mo is 0.25. The coverage of Mo less than 0.25, however, could not be determined voltammetrically due to the convolution of the charges of Mo and H.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.327-334
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• 2004

Spectroscopic and electrostatic probe measurements were made to examine plasma characteristics with or without a metal plate for a 10-㎾-class direct-current arcjet Heat fluxes into the plate from the plasma were also evaluated with a Nickel slug and thermocouple arrangement. Ammonia and mixtures of nitrogen and hydrogen were used. The NH$_3$ and $N_2$+3H$_2$ plasmas in the nozzle and in the downstream plume without a plate were in thermodynamical nonequilibrium states. As a result, the H-atom electronic excitation temperature and the $N_2$ molecule-rotational excitation temperature intensively decreased downstream in the nozzle although the NH molecule-rotational excitation temperature did not show an axial decrease. Each temperature was kept in a small range in the plume without a plate except for the NH rotational temperature for NH$_3$ gas. On the other hand, as approaching the plate, the thermodynamical nonequilibrium plasma came to be a temperature-equilibrium one because the plasma flow tended to stagnate in front of the plate. The electron temperature had a small radial variation near the plate. Both the electron number density and the heat flux decreased radially outward, and an increase in H$_2$ mole fraction raised them at a constant radial position. In cases with NH$_3$ and $N_2$+3H$_2$ a large number of NH radical with a radially wide distribution was considered to cause a large amount of energy loss, i.e., frozen flow loss, for arcjet thrusters.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.1-4
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• 2003

The design and synthesis of new polymers is desirable to obtain materials with novel physical properties. Generally, these new polymers have their well-defined nature with the number of functional groups, molecular weight, polydispersity, and the presence or absence of branching being precisely controlledl. These polymers are mainly synthesized by living polymerizations to control of their structures. Among of various living polymerization Atom transfer radical polymerization (ATRP) has been a field of intensive research in recent years1. (omitted)

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
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• pp.22-26
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• 2008

In this paper, we developed a hybrid simulation model of carbon laser ablation under the Ar plasmas consisted of fluid and particle methods. Three kinds of carbon particles, which are carbon atom, ion and electron emitted by laser ablation, are considered in the computation. In the present simulation, we adopt capacitively coupled plasma with asymmetrical electrodes. As a result, in Ar plasmas, carbon ion motions were suppressed by a strong electric field and were captured in Ar plasmas. Therefore, a low number density of carbon ions were deposited upon substrate. In addition, the plume motions in Ar gas atmosphere was also discussed.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.173-179
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• 2004

Combustion of refuse derived fuel(RDF) and refuse plastic fuel (RPF) was carried out in a lab-scale circulating fluidized bed. Experiment was investigated cold flow visualization. RDF was made by C & tech and RPF was made by KRS. The results include distribution of temperature in the combustion chamber, and concentrations of flue gas such as $O_2$, $CO_2$, CO, $NO_x$ and HCs Micro G.C(gas chromatograph) was employed to find out concentration of He Temperature distribution was different when RDF and RPF were burnt respectably. As air ratio became increased, $CO_2$, CO, and total of HCs emissions were decreased. According to the number of carbon atom of HCs, HC were classified as five kinds of HC.