• 자원환경지질
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• 제46권1호
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• pp.11-19
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• 2013

대화광상은 경기육괴의 편마암류와 화강암류에 발달한 열극을 충진 발달한 함 Mo-W 열수 맥상 광상이다. 대화광상의 몰리브덴-텅스텐 광화작용과 관련된 주요 수반광물인 석영에서 관찰되는 유체포유물은 상온 ($20^{\circ}C$) 에서의 상(phase) 관계와 냉각 및 가열 실험을 통해 측정된 균일화 온도와 상변화를 기초로 하여 3가지 주요 유형 (Type I, 액상이 우세한 $H_2O$-NaCl 유형; Type II, 기상이 우세한 $H_2O$-NaCl 유형; Type III; $CO_2-H_2O$-NaCl 유형) 으로 분류된다. 또한, 함 $CO_2$ Type III 유체포유물은 $CO_2$ 균일화 및 최종 균일화 특성을 바탕으로 4가지 유형 (IIIa, IIIb, IIIc, IIId)으로 세분된다. 대화광상 Type I 유체포유물의 균일화 온도는 약 $374^{\circ}C{\sim}161^{\circ}C$로 넓은 범위를 보여주며, 염농도 역시 약 13.6~0.5 equiv. wt. % NaCl의 넓은 조성 범위를 보인다. Type III 유체포유물 냉각 실험 시 측정된 $CO_2$ 상의 용융 온도는 $-57.4{\sim}-56.6^{\circ}C$이며, $CO_2$ 균일화 온도는 $29.0{\sim}30.8^{\circ}C$이다. 또한 $CO_2$ clathrate 용융 온도는 $7.3{\sim}9.5^{\circ}C$로 염농도는 5.2~1.0 equiv. wt. % NaCl이고, 최종 균일화 온도는 $303^{\circ}C{\sim}251^{\circ}C$로 비교적 좁은 범위로 확인되었다. $CO_2-H_2O$-NaCl계 (Type III) 유체포유물의 경우 온도가 감소함에 따라 염농도 역시 감소하는데, 이는 높은 염농도를 가진 $H_2O$-NaCl계 유체와 낮은 염농도를 가진 $CO_2-H_2O$-NaCl계 유체의 불혼화에 의해 열수의 진화가 이루어졌음을 의미한다. Type I 유체포유물은 온도 감소와 염농도 사이의 뚜렷한 변화가 인지되지 않았다. 따라서, 대화 열수계의 함 몰리브덴-중석 광화작용은 $400^{\circ}C$, 5.2 equiv. wt.% NaCl의 염농도를 가진 광화유체로부터 시작되어, 약 $350^{\circ}C$ 부근에서 유체의 불혼화 용융에 의해 진행되었다. 이후 대화 열수계에 유입된 상대적으로 낮은 온도와 염농도를 갖는 유체 (천수 또는 상대적으로 높은 물/암석 비를 갖는 열수유체) 의 혼입 작용에 의해 후기 천금속 광화작용이 야기되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.100-101
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• 2012

The plasma damage free and room temperature processedthin film deposition technology is essential for realization of various next generation organic microelectronic devices such as flexible AMOLED display, flexible OLED lighting, and organic photovoltaic cells because characteristics of fragile organic materials in the plasma process and low glass transition temperatures (Tg) of polymer substrate. In case of directly deposition of metal oxide thin films (including transparent conductive oxide (TCO) and amorphous oxide semiconductor (AOS)) on the organic layers, plasma damages against to the organic materials is fatal. This damage is believed to be originated mainly from high energy energetic particles during the sputtering process such as negative oxygen ions, reflected neutrals by reflection of plasma background gas at the target surface, sputtered atoms, bulk plasma ions, and secondary electrons. To solve this problem, we developed the NBAS (Neutral Beam Assisted Sputtering) process as a plasma damage free and room temperature processed sputtering technology. As a result, electro-optical properties of NBAS processed ITO thin film showed resistivity of $4.0{\times}10^{-4}{\Omega}{\cdot}m$ and high transmittance (>90% at 550 nm) with nano- crystalline structure at room temperature process. Furthermore, in the experiment result of directly deposition of TCO top anode on the inverted structure OLED cell, it is verified that NBAS TCO deposition process does not damages to the underlying organic layers. In case of deposition of transparent conductive oxide (TCO) thin film on the plastic polymer substrate, the room temperature processed sputtering coating of high quality TCO thin film is required. During the sputtering process with higher density plasma, the energetic particles contribute self supplying of activation & crystallization energy without any additional heating and post-annealing and forminga high quality TCO thin film. However, negative oxygen ions which generated from sputteringtarget surface by electron attachment are accelerated to high energy by induced cathode self-bias. Thus the high energy negative oxygen ions can lead to critical physical bombardment damages to forming oxide thin film and this effect does not recover in room temperature process without post thermal annealing. To salve the inherent limitation of plasma sputtering, we have been developed the Magnetic Field Shielded Sputtering (MFSS) process as the high quality oxide thin film deposition process at room temperature. The MFSS process is effectively eliminate or suppress the negative oxygen ions bombardment damage by the plasma limiter which composed permanent magnet array. As a result, electro-optical properties of MFSS processed ITO thin film (resistivity $3.9{\times}10^{-4}{\Omega}{\cdot}cm$, transmittance 95% at 550 nm) have approachedthose of a high temperature DC magnetron sputtering (DMS) ITO thin film were. Also, AOS (a-IGZO) TFTs fabricated by MFSS process without higher temperature post annealing showed very comparable electrical performance with those by DMS process with $400^{\circ}C$ post annealing. They are important to note that the bombardment of a negative oxygen ion which is accelerated by dc self-bias during rf sputtering could degrade the electrical performance of ITO electrodes and a-IGZO TFTs. Finally, we found that reduction of damage from the high energy negative oxygen ions bombardment drives improvement of crystalline structure in the ITO thin film and suppression of the sub-gab states in a-IGZO semiconductor thin film. For realization of organic flexible electronic devices based on plastic substrates, gas barrier coatings are required to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency flexible AMOLEDs needs an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}gm^{-2}day^{-1}$. The key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required (under ${\sim}10^{-6}gm^{-2}day^{-1}$) is the suppression of nano-sized defect sites and gas diffusion pathways among the grain boundaries. For formation of high quality single inorganic gas barrier layer, we developed high density nano-structured Al2O3 single gas barrier layer usinga NBAS process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nano- crystalline phase with various grain sizes in a single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the NBAS processed $Al_2O_3$ gas barrier film have improved order of magnitude compared with that of conventional $Al_2O_3$ layers made by the RF magnetron sputteringprocess under the same sputtering conditions; the WVTR of the NBAS processed $Al_2O_3$ gas barrier film was about $5{\times}10^{-6}g/m^2/day$ by just single layer.

• 한국진공학회지
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• 제19권4호
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• pp.307-313
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• 2010

본 연구에서는 열 화학기상증착법(thermal chemical vapor deposition)을 이용하여 분말 형태의 규소(Si)와 염화니켈 수화물 $(NiCl_2{\cdot}6H_2O)$을 혼합한 후 탄소공급원인 $CH_4$ 가스를 주입하여 탄화규소 나노선(SiC nanowire)을 합성하였다. 합성 온도와 $CH_4$ 가스 유량 변화에 따른 탄화규소 나노선의 구조적 특성을 분석한 결과, 합성온도가 $1,400^{\circ}C$, $CH_4$ 가스의 유량이 300 sccm인 경우가 탄화규소 나노선의 합성에 최적화된 조건임을 라만 분광법(Raman spectroscopy)과 X-선 회절(X-ray diffraction), 주사전자현미경(scanning electron microscopy), 그리고 투과전자현미경(transmission electron microscopy) 분석을 통해 확인하였다. 합성된 탄화규소 나노선의 직경은 약 50~150 nm이며, 곧은 방향성과 높은 결정성을 가지는 입방구조(cubic structure)를 지니고 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.251-252
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• 2012

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low Water Vapor Transition Rate (WVTR) of $1{\times}10^{-6}g/m^2$/day. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2$/day) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study, we developed an $Al_2O_3$ nano-crystal structure single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS system is based on the conventional RF magnetron sputtering and neutral beam source. The neutral beam source consists of an electron cyclotron Resonance (ECR) plasma source and metal reflector. The Ar+ ions in the ECR plasma are accelerated in the plasma sheath between the plasma and reflector, which are then neutralized by Auger neutralization. The neutral beam energies were possible to estimate indirectly through previous experiments and binary collision model. The accelerating potential is the sum of the plasma potential and reflector bias. In previous experiments, while adjusting the reflector bias, changes in the plasma density and the plasma potential were not observed. The neutral beam energy is controlled by the metal reflector bias. The NBAS process can continuously change crystalline structures from an amorphous phase to nano-crystal phase of various grain sizes within a single inorganic thin film. These NBAS process effects can lead to the formation of a nano-crystal structure barrier layer which effectively limits gas diffusion through the pathways between grain boundaries. Our results verify the nano-crystal structure of the NBAS processed $Al_2O_3$ single gas barrier layer through dielectric constant measurement, break down field measurement, and TEM analysis. Finally, the WVTR of $Al_2O_3$ nano-crystal structure single gas barrier layer was measured to be under $5{\times}10^{-6}g/m^2$/day therefore we can confirm that NBAS processed $Al_2O_3$ nano-crystal structure single gas barrier layer is suitable for OLED application.

• Asian Journal of Atmospheric Environment
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• 제7권2호
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• pp.72-84
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• 2013

In the study, pollution levels of indoor polycyclic aromatic hydrocarbons (PAHs) in public facilities (vapor phase or particulate phase) were evaluated, and a health risk assessment (HRA) was carried out based on exposure scenarios. Public facilities in Korea covered by the law, including underground subway stations, funeral halls, child care facilities, internet cafes (PC-rooms), and exhibition facilities (6 locations for each type of facility, for a total of 48 locations), were investigated for indoor assessment. For the HRA, individual excess cancer risk (ECR) was estimated by applying main toxic equivalency factor (TEF) values suggested in previous studies. Among the eight public facilities, internet cafes showed the highest average $PM_{2.5}$ concentration at $110.0{\mu}g/m^3$ (range: $83.5-138.5{\mu}g/m^3$). When assuming a risk of facility exposure time based upon the results of the surveys for each public facility, the excess cancer risk using the benzo(a)pyrene indicator assessment method was estimated to be $10^{-7}-10^{-6}$ levels for each facility. Based on the risk associated with various TEF values, the excess cancer risk based upon the seven types cancer EPA (1993) and Malcolm & Dobson's (1994) assessment method was estimated to be $10^{-7}-10^{-5}$ for each facility. The excess cancer risk estimated from the TEF EPA (2010) assessment was the highest: $10^{-7}-10^{-4}$ for each facility. This is due to the 10-fold difference between the TEF of dibenzo(a,e)fluoranthene in 2010 and in 1994. The internet cafes where smoking was the clear pollutant showed the highest risk level of $10^{-4}$, which exceeded the World Health Organization's recommended risk of $1{\times}10^{-6}$. All facilities, with the exception of internet cafes, showed a $10^{-6}$ risk level. However, when the TEFs values of the US EPA (2010) were applied, the risk of most facilities in this study exceeded $1{\times}10^{-6}$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.157-157
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• 2015

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}g/m^2day$. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2day$) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study NBAS process was introduced to deposit enhanced film density single gas barrier layer with a low WVTR. Fig. 1. shows a schematic illustration of the NBAS apparatus. The NBAS process was used for the $Al_2O_3$ nano-crystal structure films deposition, as shown in Fig. 1. The NBAS system is based on the conventional RF magnetron sputtering and it has the electron cyclotron resonance (ECR) plasma source and metal reflector. $Ar^+$ ion in the ECR plasma can be accelerated into the plasma sheath between the plasma and metal reflector, which are then neutralized mainly by Auger neutralization. The neutral beam energy is controlled by the metal reflector bias. The controllable neutral beam energy can continuously change crystalline structures from an amorphous phase to nanocrystal phase of various grain sizes. The $Al_2O_3$ films can be high film density by controllable Auger neutral beam energy. we developed $Al_2O_3$ high dense barrier layer using NBAS process. We can verified that NBAS process effect can lead to formation of high density nano-crystal structure barrier layer. As a result, Fig. 2. shows that the NBAS processed $Al_2O_3$ high dense barrier layer shows excellent WVTR property as a under $2{\times}10^{-5}g/m^2day$ in the single barrier layer of 100nm thickness. Therefore, the NBAS processed $Al_2O_3$ high dense barrier layer is very suitable in the high efficiency OLED application.

• 한국진공학회지
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• 제21권3호
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• pp.136-141
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• 2012

열처리 공정으로 제조한 $In_2Se_3$ 박막의 구조 및 광학적 물성을 조사하여 보고한다. 기판위에 스퍼터링 방법으로 인듐(In: indium)을 증착하고 셀레늄 분위기에서 열처리 온도를 변화시키며 In-Se 박막을 제조하였다. 열처리 온도가 증가함에 따라 $In_2Se_3$ 박막의 형성과 상의 변화를 관찰 할 수 있었다. 낮은 열처리 온도(${\leq}150^{\circ}C$)에서는 In의 뭉침 현상을 관찰할 수 있었고 열처리 온도가 $250^{\circ}C$ 부터 $In_2Se_3$ 박막이 형성되며 $350^{\circ}C$ 에서 ${\gamma}-In_2Se_3$ 상이 형성됨을 알 수 있었다. 열처리 온도가 $400^{\circ}C$로 증가면 wurtzite 구조의 고품질 ${\gamma}-In_2Se_3$ 박막을 얻을 수 있었다. 열처리 온도가 증가함에 따라 $In_2Se_3$ 박막의 밴드갭이 증가함을 알 수 있었고, 열처리 온도 $400^{\circ}C$에서 제조된 ${\gamma}-In_2Se_3$ 결정질 박막의 밴드갭이 1.796eV임을 알았다.

• 한국지구과학회지
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• 제31권3호
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• pp.288-299
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• 2010

본 연구는 과학적 소양은 과학적 지식의 획득과 과학적 담화에 참여할 수 있는 언어적 능력을 통하여 길러진다는 전제하에 대기 중의 물의 상태변화에 관한 학생 글에서 나타나는 의미관계와 과학 언어적 특징을 알아보았다. 중학교 3학년 학생 67명이 참여하여 일상생활에서 흔히 경험할 수 있는 현상과 학교과학교육에서 체계적으로 배우는 현상 에 관한 두 개의 서술형 문항에 대한 글을 작성하였다. 연구의 결과 학생들은 '이슬점' 같은 생소한 용어뿐만 아니라 '수증기', '김' 등과 같은 친숙한 용어에 대해서도 잘못된 의미관계를 형성하고 있었고, 학교과학 교육보다 일상의 경험에서 형성된 지식에서 옳은 의미관계와 잘못된 의미관계 모두 더 많이 나타났다. 일상의 과학적 현상에 대해서는 행위와 절차를 중심으로 한 서술 양상이, 학교 교육에 의해 접하게 된 현상에 대해서는 전문용어와 명사구의 사용 양상이 보였다. 본 연구를 통하여 경험에 기초한 자발적 과정은 풍부한 의미관계 형성에, 형식적이고 이론적인 과정은 명사화를 중심으로 한 전문적이고 추상적인 서술의 측면에서 과학적 언어 능력 발달에 기여함을 알 수 있었다.

• 한국대기환경학회지
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• 제31권6호
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• pp.548-561
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• 2015

Atmospheric concentrations of polychlorinated dibezo-p-dioxins and furans (PCDD/Fs) were investigated at urban-residential (Group I: Suwon, Guri and Goyang), industrial (Group II: Ansan, Siheung and Bucheon), urban-rural mixed (Group III: Yangju, Pocheon and Dongducheon) and rural regions (Group IV: Yangpyeong) in Gyeonggi-do from February 2012 to November 2012 quarterly. The concentrations of PCDD/Fs ranged from 0.018 to $0.109pgTEQm^{-3}$ in Group I (mean value: $0.061pgTEQm^{-3}$), 0.059 to $0.367pgTEQm^{-3}$ in Group II (mean value: $0.179pgTEQm^{-3}$), 0.072 to $0.836pgTEQm^{-3}$ in Group III (mean value: $0.334pgTEQm^{-3}$) and 0.014 to $0.066pgTEQm^{-3}$ in Group IV (mean value: $0.034pgTEQm^{-3}$), respectively. In spite of the less PCDD/F emission sources than Group II (industrial regions), the level of PCDD/Fs in urban-rural mixed area showed the highest values with high fluctuation. It's likely that the Group III was affected by fugitive emissions such like biomass burning and unregulated open burning. The mean contribution of particle phase to total PCDD/F concentration was above 83% because most of PCDD/F congeners were partitioned into particle phase. We evaluated their gas-to-particles equilibriums with the regression between the particle-gas partition coefficient, $K_P(m^3{\mu}g^{-1})$ and corresponding subcooled liquid vapor pressure ($P_L$). The logarithm-$K_P$ of PCDD/Fs was poorly correlated with $P_L$ at low ambient temperature (below $10^{\circ}C$) and the slope (m) values for log-log plots of the $K_P$ vs. $P_L$ was steeper in the Group 2 and Group 3 than residential area. It implies that the slope values were likely influenced by both the direct emission source of PCDD/Fs and ambient temperature.

• 한국화재소방학회논문지
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• 제13권1호
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• pp.37-47
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• 1999

부유중인 분진의 화재 및 용기 또는 파이프의 미세한 균열에서 비산되는 가연성 액체의 분무화재의 위험성은 착화후의 고속 확산과 높은 열방출율로 인하여 매우 높은 것으로 알려졌다. 이에 대한 연구는 주로 실험적으로나 또는 거시적인 관점의 해석으로 제한되어 왔다. 본 연구는 미시적인 관점의 해석으로서 분진 및 분무를 가연성 미세 액적으로 가정하여 그의 증발과 착화에 대하여 연구하였다. 첫 단계로서 일열의 액적 배열을 계산영역으로 하여, 비정상 이차원 보존방정식들을 적용하였다. 수치해석은 일반화된 비직교 좌표계를 사용하였고, 화학반응은 Arrhenius의 법칙에 의하여 반응속도가 제어되는 일단계 반응을 고려하였다. 계산결과는 액적 주위의 온도와 반응물질의 농도분포를 시간에 따라 보여준다. 주위의 산소가 증발하는 액적의 연료와 섞이기 시작하고 착화 조건에 다다르면, 급격한 발열반응이 예혼합된 가스로부터 일어나기 시작한다. 최대온도 영역은 점차적으로 액적 표면으로 이동하며 최대온도는 착화이후 급격히 상승한다. 연료와 산소의 농도는 최대온도 영역 근처에서 최소값을 보인다. 따라서 착화순간에는 예혼합연소의 양상을 띠는 것으로 나타났다. 이후에는 예혼합 가스의 소멸로 확산연소의 양상을 띠게 된다. 액적간의 거리는 중요한 요소로서 멀리 떨어져 있는 경우부터 액적간의 거리가 가까워지면 착화지연 시간이 줄여들어 착화가 빨리 일어나는 것으로 관찰되었다. 또한 착화 후에는 최대온도 영역이 일열의 중심선으로부터 멀어지는 것으로 나타났는데 이것은 중심부근의 산소가 먼저 소모되고 외부로부터의 산소공급도 화염에 의해 차단되어 나타나는 현상이다. 이번 연구로 미세적인 착화현상에 대한 이해를 높이게 되었고 추후 복잡한 배열에 대한 연구도 가능할 것이다.