• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.39-42
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• 2007

최근 C-H 수소결합의 강한 상한 상호작용에 의하여 blue shift를 나타내는 현상이 보고 되고 있다. 비정질 불화탄소의 화학적 이동유기 절연막의 경우, 화학적 이동의 원인은 매우 서로 다른 원인에 발생하지만 이러한 물질의 상호작용은 친핵성 첨가반응에 의한 것임을 확인하였다. a-C:F 박막의 화학적 이동은 XRD 패턴에 의해서 결합 구조와 연관이 있으며, C-H 결합이 불소에 의한 끌림현상으로부터 발생되면서 비정질 구조로 변하는 것을 확인하였다.

• Clean Technology
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• v.19 no.2
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• pp.113-120
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• 2013

The treatment of chemically stable perflourocompounds (PFCs) requires a large amount of energy. An energy efficient arc plasma system has been developed to overcome such disadvantage. $CF_4$, $SF_6$ and $NF_3$ were injected into the plasma torch directly, and net plasma power was estimated from the measurement of thermal efficiency of the system. Effects of net plasma power, waste gas flow rate and additive gases on the destruction and removal efficiency (DRE) of PFCs were examined. The calculation of thermodynamic equilibrium composition was also conducted to compare with experimental results. The average thermal efficiency was ranged from 60 to 66% with increasing waste gas flow rate, while DRE of PFCs was decreased with increasing gas flow rate. On the other hand, DRE of each PFCs was increased with the increasing input power. Maximum DREs of $CF_4$, $SF_6$ and $NF_3$ were 4%, 15% and 90%, respectively, without reaction gas at the fixed input power and waste gas flow rate of 3 kW and 70 L/min. A rapid increase of DRE was found using hydrogen or oxygen additional gases. Hydrogen was more effective than oxygen to decompose PFCs and to control by-products. The major by-product in the arc plasma process with hydrogen was hydrofluoric acid that is easy to be removed by a wet scrubber. DREs of $CF_4$, $SF_6$ and $NF_3$ were 25%, 39% and 99%, respectively, using hydrogen additional gas at the waste gas flow rate of 100 L/min and the input power of 3 kW.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.11
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• pp.1031-1037
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• 2000

Isothermal vapor-liquid equilibrium(VLE) data have been obtained for the systems of propane(R290)+1,1,1,2-tetrafluoroethane(R134a) and 1,1,1,2-tetrafluoroethane(R134a)+isobutane(R60A) in the temperature range of 253.15 to 323.15K. Experiments were performed in a circulation type apparatus by injecting vapor through liquid pool using a magnetic pump. Both systems form azeotropes in the temperature range of this study. The experimental results were estimated with the Peng-Robinson equation of state. When the temperature-dependent binary interaction parameter was used in the Peng-Robinson equation of state, the absolute average deviation of the measured bubble point pressures from the values correlated by the Peng-Robinson equation was 0.65% and 0.78% for R290+R134a and R134a+600a, respectively. Azeotropic compositions for both systems were presented.

• Journal of the Korean Vacuum Society
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• v.21 no.2
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• pp.99-105
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• 2012

We fabricated the textured silicon (Si) surface on Si substrates by the electrochemical etching using gold (Au) nanoparticle catalysts. The antireflective property of the fabricated Si nanostructures was improved. The Au nanoparticles of ~20-150 nm were formed by the rapid thermal annealing using thermally evaporated Au films on Si. In the chemical etching, the aqueous solution containing $H_2O_2$ and HF was used. In order to investigate the effect of electrochemical etching on the etching depth and reflectance characteristics, the sample was immersed in the aqueous etching solution for 1 min with and without applied cathodic voltages of -1 V and -2 V. As a result, the solar weighted reflectance, i.e., the averaged reflectance with considering solar spectrum (air mass 1.5), could be efficiently reduced for the electrochemically etched Si by applying the cathodic voltage of -2 V, which is expected to be useful for Si solar cell applications.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.3
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• pp.248-255
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• 2016

The leaves of three plant species, such as soybean, raspberry, and kudzu, exposed to hydrogen fluoride was collected in an area surrounding an emission source where the release accident occurred. The ultrasonic-assisted extraction and analysis of fluoride by ion chromatography was carried out. The mean concentration of fluoride in the leaves of three plant species exposed to hydrogen fluoride was $5,409{\pm}1,198mg\;F/kg\;dry\;wt$ and $788{\pm}339mg\;F/kg\;dry\;wt$, respectively. The mean fluoride concentration in ambient air were estimated to be $2.36{\pm}0.65mg/m^3$ ($2.89{\pm}0.79ppm$) and $0.35{\pm}0.15mg/m^3$ ($0.43{\pm}0.19ppm$) in exposed and unexposed sites, respectively. It seems likely that the passive monitoring using plant leaves could identify with respect to plant risk by fluoride in atmosphere.

• Microbiology and Biotechnology Letters
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• v.17 no.1
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• pp.51-55
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• 1989

The conjugally transferred TOL plasmid or NAH plasmid was stably maintained and expressed in n-alkane assimilating Pseudomonas putida KCTC 2405. However, these plasmids were not able to coexist in this strain because of incompatibility. The incompatibility of TOL and NAH plasmid was bypassed using CAM::TOL* plasmid, which was constructed by the transposition of only tol gene without incompatibility system in TOL plasmid into CAM plasmid. p. putida 3SK capable of growing on m-toluate, naphthalene, camphor, and n-alkane(C8-C24) was constructed by the conjugal transfer of NAH plasmid into n-alkane assimilating p. putida SK carrying CAM:: TOL* plasmid. CAM::TOL＊ plasmid in p. putida 3SK was stable on the selective media but unstable on the nonselective media.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.137-140
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• 2012

현대의 건축 재료는 각종 고분자 화합물의 비중이 커지고 있어 건축 재료가 연소할 때 발생하는 가스의 성분비가 천연재료를 이용하던 과거의 건축물과 차이를 보인다. 실제로 근래의 건축재료 연소가스의 정성분석결과에서도 천연재료의 연소가스에서 발견되는 CO, $CO_2$ 외에도 HF, HCN, HBr, HCl, NO, $NO_2$, $SO_2$등의 화학종이 발견되고 있다. 이러한 화학종들은 고분자 화합물에서 발생하는 것으로 분석되며, 건축 재료에서 화합물의 비중이 높아지는 만큼 향후 이러한 화학종들이 건축물의 화재에서 대피의 주요 방해요인으로 작용할 수 있다. 이에 본 연구에서는 HF를 대상으로 동물 노출실험을 통하여 얻은 결과와 HF에 대한 기존연구를 비교 분석하여 HF의 독성에 대한 기초 연구를 수행하였다.

• Journal of The Korean Society of Clinical Toxicology
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• v.2 no.1
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• pp.63-66
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• 2004

Hydrofluoric acid (HF), one of the strongest inorganic acids, is used mainly for industrial purpose. Hydrofluoric acid injuries has a potential for both systemic as well as severe local tissue destruction. One of the most serious consequences of severe exposure to HF by any route is marked lowering of serum calcium (hypocalcemia) and other metabolic changes, such as hypomagnesemia and which may result in a fatal outcome if not recognized and treated. promptly cardiotoxicity is not well known except arrhythmias, which are a primary cause of death. We report a case of myopericarditis by ingestion of hydrofluoric acid.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.12
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• pp.1132-1138
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• 2005

Recently, production and use of freon substances are restrained due to depletion of ozone layer and global warming. In this aspect of environmental problems, the best solution is to use the natural refrigerant such as ammonia. Thus, this study is to find the optimal operating conditions by comparing the performance between the shell and tube type and shell and disk type heat exchangers using the ammonia refrigerant, and to verify the superiority of the shell and disk type heat exchanger that is not used in field of refrigeration and air conditioning. Finally, this study shows that the shell and disk type heat exchanger is applicable to the ammonia refrigeration system, and this system minimizes the refrigerant charge and installation space.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.554-554
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• 2009

지구온난화는 범지구적 환경문제로 매우 빠른 속도로 진행되면서 그 심각성을 더해가고 있다. 특히 해수면 상승이나 대형 태풍, 홍수, 가뭄 등의 이상기후가 빈번하게 발생되며 생태계에도 심각한 타격을 주고 있다. 이러한 지구온난화를 유발하는 물질들에 대해 도쿄의정서(Annex A)에 6대 온실가스($CO_2$ (이산화탄소), 메탄($CH_4$), $N_2O$(아산화질소), PFC(불화탄소), HFC(수소화불화탄소), $SF_6$(육불화황))로 정의 하여 규제대상으로 분류하고 있다. $CO_2$를 제외한 Non-$CO_2$ 온실가스들은 배출량이 $CO_2$에 비해 매우 낮지만 GWP(지구온난화지수)가 매우 커 지구온난화에 미치는 영향이 상당하다. 최근 이산화탄소 이외에 지구온난화 문제를 일으키는 온실가스에 대한 많은 관심으로 대상가스의 처리 또는 재활용을 위한 신기술 및 신공정 개발에 박차를 가하고 있다. 온실가스 중 HFCs는 GWP가 1300으로 미량의 배출로도 심각한 기후변화를 일으킬 수 있는 물질로, 우리나라의 경우 1990년 이후 HFCs 배출량 증가율은 연 평균 4.9% ~ 13.8%이다. 국내외 온실가스 처리기술은 대부분 CO2에 대한 연구개발 및 실증화가 지배적이고, non-CO2에 대한 처리기술 개발수준은 미흡할 뿐만 아니라 본 연구 대상인 HFCs 의 경우에는 처리기술 연구개발이 전무하다. 특히 HFCs는 냉매 또는 발포제로 사용되는데 일반적으로 사용 후 특별한 처리과정 없이 대기중으로 배출된다. 본 연구에서는 non-CO2 가스인 HFC-134a 를 대상으로 혼합가스에서 분리 회수를 위해 하이드레이트 기술을 접목시켜 경제적, 친환경적인 기술개발을 목적으로 한다. kinetic 반응장치와 고압반응기 및 magnetic drive system 을 이용하여 stirring speed와 driving force에 따른 HFC-134a 하이드레이트 형성속도의 상관관계를 제시하고자 한다.