• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1475-1477
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• 2003

본 논문에서는 LNG/LPG 센서와 솔벤트 센서를 국산화한 결과를 보고한다. LNG/LPG 센서는 $SnO_{2-}\;WO_3$ 모물질에 Pd, Pt 촉매를 첨가하여 제작하였다. 센서를 $400^{\circ}C$ 이상에서 동작시키면 CO가 촉매층에서 거의 $CO_2$로 산화되어 감지막의 저항변화에 아무런 기여도 못하기 때문에 팔라듐 촉매 센서부와 백금촉매 센서부의 신호로부터 탄화수소와 CO를 구별할 수 있다. 또한 촉매층 위에 다공성 보호층를 형성하여 촉매층과 감지막을 보호함으로써 장기 안정성이 크게 향상 되었다. 한편, 감지물질로 $BaSnO_3$를 사용해 제작된 솔벤트 센서는 에탄올에 매우 우수한 감도와 선택성을 나타내었다.

• Composites Research
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• v.29 no.1
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• pp.40-44
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• 2016

Nuclear fuel cladding used in a nuclear power plant must possess superior oxidation resistance in the coolant atmosphere of high temperature/high pressure. However, as was the case for the critical LOCA (loss-of-coolant accident) accident that took place in the Fukushima disaster, there is a risk of hydrogen explosion when the nuclear fuel cladding and steam reacts dramatically to cause a rapid high-temperature oxidation accompanied by generation of a huge amount of hydrogen. Hence, an active search is ongoing for an alternative material to be used for manufacturing of nuclear fuel cladding. Studies are currently aimed at improving the safety of this cladding. In particular, ceramic-based nuclear fuel cladding, such as SiC, is receiving much attention due to the excellent radiation resistance, high strength, chemical durability against oxidation and corrosion, and excellent thermal conduction of ceramics. In the present study, cladding with $SiC_f/SiC$ protective films was fabricated using a process that forms a matrix phase by polymer impregnation of polycarbosilane (PCS) after filament-winding the SiC fiber onto an existing Zry-4 cladding tube. It is analyzed the oxidation and microstructure of the metal cladding with $SiC_f/SiC$ composite protective films using a drop tube furnace for thermal shock test.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.37-40
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• 2009

불소가 도핑된 산화주석(SnO2:F, FTO) 박막은 다결정 전도성 세라믹으로 가시광선 영역에서 투명하기 때문에 태양전지의 전극으로 활용된다. 본 연구에서 FTO는 APCVD법으로 성막되었다. BSG기판을 사용하여 $620^{\circ}C$의 고온에서 공정이 진행되었다. 이렇게 제작된 FTO 박막은 수소, 질소, 대기 분위기에서 여러 열처리 시간을 변수로 실험하여 열처리 전후의 전기적, 광학적, 구조적 변화를 관찰하고 분석하였다. 전기적 특성 분석에는 전기 비저항, 모빌리티 및 캐리어 농도 등의 변화를 알아보았고, 광학적 분석에는 UV-vis spectoscopy로 200nm에서 800nm 파장대역의 투과도를 구하고, Hazemeter를 통하여 총투과율, 평행투과율, 확산투과율 및 Haze를 분석하여 FTO막이 가지고 있는 texturing에 의한 효과를 알아보기 위하여 시편의 열처리 전후를 비교 분석하였다. 구조적 분석은 XRD를 이용하여 pattern을 분석하여 FTO가 가지는 구조변화를 분석하였다. 특히 FTO의 texturing에 기여도가 높은 (200)면의 XRD peak강도가 상승함에 따라 후열처리에 의해 박막의 표면의 변화가 일어남을 확인하였다. FTO의 후열처리에 의한 변화는 전기적으로는 약간의 전기 비저항의 증가를 가져오며, 캐리어 농도의 감소를 가져온다. 캐리어 농도의 감소에 따라 모빌리티의 상승이 관찰되었다. 광학적 특성은 가시광선 영역에서 투과율은 거의 같거나 약간 감소하는 경향을 나타내며, 후열처리 전후에 거의 동일한 투과율을 보이면서도 확산 투과율이 상승하는 분석 결과를 얻었다.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.657-662
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• 1999

Mn-Ni oxide thin films for NTC thermistor application were sputtered on alumina substrates at $320^{\circ}C$ Effects of various oxygen partial pressures and annealing temperatures on the microstructure, crystal phase, resistivity and B constant were investigated. In general, microstructure of the films deposited was columnar grain structure. After annealing at $700^{\circ}C$, the microstructure was begun to transform to equiaxed grain structure. Most of the phases were mixture of cubic spinel and $Mn_2$$O_3$. As the oxygen concentration increased, the resistivity and B constant were greatly decreased, and these values become low and stable after annealing between $600^{\circ}C$ and $700^{\circ}C$.

• Polymer(Korea)
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• v.36 no.4
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• pp.531-535
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• 2012

Conductive polyaniline (PANI) nanofibers in UV-curable resin were used for a transparent conductive film. The emeraldine-salt PANI (ES-PANI) nanofibers were prepared by chemical oxidation polymerization of aniline, which could be changed into emeraldine-base PANI by dedoping. EB-PANI nanofibers as a precursor for conductive fillers were thereby transformed into re-dpoed PANI (rES-PANI) by dodecylbenzenesulfonic acid in the UV-curable resin solution. rES-PANI nanofibers have high conductivity and long-term stability in the solution without a defect of nanostructure. The resulting conductive resin solution was proved to be highly stable where no precipitation of rES-PANI fillers was observed over a period of 3 months. The transparent film was spin-casted on a poly(methyl methacrylate) sheet of thickness ca. $5{\mu}m$. A surface resistance of $6.5{\times}10^8{\Omega}/sq$ and transmittance at 550 nm of 91.1% were obtained for the film prepared with a concentration of 1.4 wt% rES-PANI nanofibers in the solution. This transformation process of rES-PANI from ES-PANI by dedoping-redoping can be an alternative method for the preparation of an antistatic protection film with controllable surface resistance and optical transparencies with the PANI concentration in UV-curable solution.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.757-764
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• 2012

The surface of graphite fiber fabric anode was modified with a hydrogel and a mixture of hydrogel and multiwall carbon nanotube, and their effectiveness were compared to the unmodified anodes in a batch microbial fuel cell (microbial fuel cells). The maximum power density of the MFC was determined by both performance of the anode and cathode. The maximum power density for the MFC with the anode modified with the mixture of hydrogel and multiwall carbon nanotube was $1,162mW/m^2$ which was 27.7% higher than that with the unmodified graphite fiber fabric anode. "The mixture of hydrogel and multiwall carbon nanotube is a good surface modifier for anode with high biological affinity and low activation losses."

• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.15-18
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• 2000

Transparent conducting tin (IV) oxide thin films have been studied and developed for the electrode materials of solar cell substrate. Fabrication of tin oxide thin films by sol-gel method is process development of lower cost photovoltaic solar cell system. The research is focused on the establishment of process conditions and development of precursor. The precursor solution was made of tin isopropoxide dissolved in isopropyl alcohol. The hydrolysis rate was controlled by addition of triethanolamine. Dip and spin coating technique were applied to coat tin oxide on borosilicate glass. The resistivity of the thin film was lower than 0.01-cm and the transmittance is higher than $90\%$ in a visible range.

• Journal of Plant Biotechnology
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• v.31 no.2
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• pp.109-113
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• 2004

In order to develop transgenic potato plants with enhanced tolerance to multiple stress, we constructed the transformation vector expressing both superoxide dismutase and ascorbate peroxidase genes in chloroplasts under the control of a stress-inducible SWPA2 promoter. Transgenic potato plants (cv. Superior and Atlantic) were generated using an Agrobacterium-mediated transformation system. Transgenic potato plants were regenerated on MS medium containing 100mg/L kanamycin. Genomic Southern blot analysis confirmed the incorporation of foreign genes into the potato genome. When potato leaf discs were subjected to methyl viologen (MV) at 10 $\mu$M, transgenic plants showed higher tolerance than non-transgenic or vector-transformed plants. To further study we selected the transgenic plant lines with enhanced tolerance against MV. These plants will be used for further analysis of stress-tolerance to multiple environmental stresses.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.213-217
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• 2009

Microbial fuel cells (MFCs) have been known as a new alternative energy conversion technology for treating wastewater and producing electricity simultaneously. A MFC converts the chemical energy of the organic compounds to electrical energy through microbial catalysis at the anode under anaerobic conditions. To examine the performance of MFC, in this work, the characteristics of the efficiency of wastewater treatment and generation of electricity was evaluated for sewage. When acetate as a carbon source was added into the sewage, the removal efficiency of COD was increased from 75.7% to 88.2% and the voltage was increased significantly from 0.22 V to 0.4 V. The influence of distance between anode and cathode was examined and the effect of the surface area of anode was investigated under the various external resistances. It was found that the maximum power density was $610mW/m^2$ and power generation was effective when the distance between the electrodes was shorter and the surface area of the anode was smaller.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.73-73
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• 2011

Zn-Sn-O (ZTO) 다성분계 산화물 박막은 일반적인 rf 스퍼터법으로 성막할 경우 비정질상으로 성장하여 결정질 산화물 박막에 비해 우수한 표면평탄도와 식각 단면을 제공한다. 비정질임에도 불구하고 넓은 자유전하 농도 범위에서 높은 Hall 이동도를 제공할 수 있는 것으로 보고되어 있어 비정질 산화물의 투명도전성 박막에 대한 관심이 높아지고 있다. 투명 TFT에 적용되는 또 다른 비정질계 산화물 박막인 In-Zn-O (IZO) 박막에 비해 ZTO 박막은 상대적으로 제한된 연구가 이루어졌으나, In의 함유되지 않아 경제적으로 유리하고, 특히 SnO2의 우수한 기계적 및 화학적 특성과 ZnO의 내환원성 특성을 잠재하고 있는 유망한 투명도전성 박막재료이다. 본 연구에서는 Zn-Sn-O계 박막을 통상의 rf 스퍼터법으로 성막하여 조성, 증착 온도, 그리고 열처리 온도에 따른 ZTO 박막의 구조적인 특성 변화와 이에 따른 전기적 및 광학적 특성 변화에 대하여 고찰하였다. ZnO 타겟과 SnO2 타겟을 사용하여 co-sputtering하여 ZnO의 부피 분률을 13~59 mol%까지 변화되도록 조절하여 증착하였다. 증착 온도는 상온, 150 및 $300^{\circ}C$로, 그리고 성막가스 중의 산소분률은 0%, 0.5% 및 1% 로 변화시켰다. 40 mol% 이상의 ZnO를 함유한 ZTO 박막은 가시광 영역에서의 평균 광투과도는 좋으나 전기적인 특성이 열악하였으며, ZnO 분율이 낮은 ZTO 박막은 10-2~10-3 ohm-cm 정도의 비교적 낮은 비저항을 나타내었으나 광투과도 면에서 떨어지는 단점을 보였다. 평균 광투과도는 증착 온도가 증가할수록, 그리고 산소의 양이 증가할수록 향상 되었다. 자유전하농도가 1017~1020 cm-3 정도의 넓은 범위에서 10 cm2/Vs 을 넘는 홀 이동도를 가지는 ZTO 박막의 증착이 가능함을 확인하였으며, 이로부터 투명 TFT 소자로 적용이 가능성이 있음을 보였다. EPMA를 이용한 정량분석 및 XRD를 이용한 구조분석과 연계한 ZTO 박막의 물성 및 최적 조건에 대한 논의가 이루어질 것이다.