• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.414-423
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• 2007

Field Emission Display(FED) has significant advantages over existing display technologies, particularly in the area of small and high quality display. In order to test the feasibility of fabricating the System-on-Chip(SOC) with FED, we conducted the experiment to use the p-n junction as an electron beam source for the flat panel display. A novel structure was constructed to form p-n junctions by generating inversion layer with the electric field from the cantilever style gate. When we applied more than 220V at the cantilever style gate which has a height of $1{\mu}m$, avalanche breakdown onset was successfully achieved. The characteristics was compared with the electron emission from the ultra shallow junction in the avalanche region. The experiment result and the future direction were discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.157-158
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• 2013

Organic solar cell was fabricated using one-pot deposition of a mixture of NiO nanoparticles, P3HT and PCBM. In the presence of NiO, the photovoltaic performance was slightly increased comparing to that of the device without NiO. When $TiO_2$ thin films with a thickness of 2~3 nm was prepared on NiO nanoparticles using atomic layer deposition, the power conversion efficiency was increased by a factor 2.5 with respect to that with bare NiO. Moreover, breakdown voltage of the film consisting of NiO, P3HT, and PCBM on indium tin oxide was increased by more than 1 V in the presence of $TiO_2$-shell on NiO nanoparticles. It is evidenced that S atoms of P3HT can be oxidized on NiO surfaces, and $TiO_2$-shell on NiO nanoparticles. It is evidenced that S atoms of P3HT can be oxidzed on NiO surfaces, and $TiO_2$ shell heavily reduced oxidation of S at oxide/P3HT interfaces. Oxidized S atoms can most likely act as carrier generation sites and recombination centers within the depletion region, decreasing breakdown voltage and performance of organic solar cells. Our result shows that fabrication of various core-shell nanostruecutres of oxides by atomic layer deposition with controlled film thickness can be of potential importance for fabricating highly efficient organic solar cells.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.45-45
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• 2012

초고분자량 폴리에틸렌(UHMWPE)섬유는 현재까지 알려져 있는 섬유중 비강도가 가장 우수하며 강도 또한 최고 40g/d를 나타내는 슈퍼섬유중에 하나이다. UHMWPE섬유는 비교적 간단한 분자구조로 이루어져 있으며 높은 결정화도로 인해 광 안정성 및 자외선 저항성이 우수하며 내마모성도 뛰어나다. 이러한 특성으로 인해 최근 로프 및 어망 등의 산업적 용도 뿐만 아니라 익스트림 스포츠웨어를 포함한 의류소재에도 다양하게 적용되고 있다. 하지만 의류소재 적용에 앞서 초소수성으로 이루어진 분자구조와 낮은 내열성으로 인해 염색이 쉽지 않으며 다양한 색상을 구현하기가 힘든 실정이다. 현재 본 연구실에서는 이와 같은 문제점을 해결하기 위해 UHMWPE섬유에 염색이 가능한 염료를 개발하였으며 보다 다양한 색상을 구현하기 위해 연구를 진행 중이다. 현재 본 연구실에서는 UHMWPE섬유 염색에 있어 Blue, Red, Yellow, Magenta 계열의 색상구현이 가능하며 보다 심색화 된 색상을 구현함으로 인해 의류용 섬유소재 및 산업용 섬유소재에 다양하게 적용할 수 있도록 UHMWPE섬유용 염료합성 실험이 진행되고 있다. 안트라퀴논 및 아조계 염료에 초소수성 알킬체인을 치환함으로써 염료의 소수성을 증가시켜 초소수성 섬유인 UHMWPE섬유에 염착성을 증가시키고 높은 견뢰도 결과를 확보하였다. 또한 내열성이 낮은 특성에도 불구하고 염색 이후 UHMWPE섬유가 가지는 물성에는 큰 변화를 나타내지 않았다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.21-21
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• 2012

수송용 산업의 하나인 국내 조선업계는 2008년 말 이후 세계 조선경기 불황 속에서도 2009년 451억달러, 2010년 491억달러의 사상최대 수출액을 달성한 바가 있고 세계 조선사 순위에서는 1위에서 5위까지 한국 조선소 등이 우위를 차지하고 있다. 그러나 개별 기업 경쟁력은 우위에 서있지만 중국과의 격차가 많이 좁혀지고 있어 안심할 수 없는 상황이다. 특히 최근에는 탄소배출량이 적은 친환경 선박의 제조가 선박업계 전반의 화두로 대두되고 있다. 이를 위해 다양한 시도가 시도되고 있는데 그중에 하나가 선박의 경량화이다. 금속외장 전선은 선박 무게의 10~13%를 차지하고 있고 전체 사용 전선의 30~40%를 차지하고 있어 선박에서의 금속외장 전선의 무게를 줄이기 위한 연구가 필요한 실정이다. 또한 조선산업 뿐만 아니라 자동차 분야에서도 금속 외장전선이 많이 사용되고 있으며, 자동차의 연비 향상을 위한 경량화 연구가 더욱 절실한 상황이다. 본 연구에서는 수송용으로 사용되는 전선의 금속외장을 경량 고강도 섬유를 활용한 하이브리드 wire로 대체하기 위한 편조 기술 및 편조 장치를 개발하기 위한 설계 및 기초연구를 수행하였다. 초경량 고강도 섬유 Armor의 제조기술 및 최적 공정 개발을 위한 연구로서 경쟁사 샘플에 대한 분석을 실시하였고, 사용된 섬유의 성분 분석 및 물성시험을 수행하였다. 또한 원형직기 개발을 위한 구조부 설계를 위해 ANSYS해석을 수행하고 저신율 고강도인 아라미드의 이징모션 시스템 개발을 위한 연구를 수행하였으며 개구 형성방법을 설계하였다. 그리고 초경량 고강도 hybrid 케이블 아라미드 편조 표면 및 내부 가교에 의한 가공 기술을 연구하였다. 아라미드 섬유의 발수성 향상을 위한 코팅재료 선정을 위한 연구를 수행하였고, 자외선 경화공정에서 조건별 데이터를 정립하여 솔루션을 제공하고자 한다.

• Journal of Powder Materials
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• v.10 no.6
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• pp.383-389
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• 2003

As in other areas of materials technology, the tendency towards light weight constructions becomes more and more important also for powder metallurgy. The development is mainly driven by the automotive industry looking for mass reduction of vehicles as a major factor for fuel economy. Powder metallurgy has to offer a number of interesting areas including the development of sintered materials of light metals. PM aluminium alloys with improved properties are on the way to replace ferrous pars. For high temperature applications in the engine, titanium aluminide based materials offer a great potential, e.g. for exhaust valves. The PM route using elemental powders and reactions sintering is considered to be a cost effective way for net shape parts production. Furthermore it is expected that lower costs for titanium raw materials coming from metallurgical activities will offer new chances for sintered parts with titanium alloys. The field of cellular metals expands with the hollow sphere technique, that can provide materials of many metals and alloys with a great flexibility in structure modifications. These structures are expected to be used in improving the safety (crash absoption) and noise reduction in cars in the near future and offer great potential for many other applications.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.166-166
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• 2011

한국건설기술연구원내에 세계 최초로 UHPC(초고성능 콘크리트)를 활용한 보도사장교를 설계 및 시공하여 공용중이다. 초고성능 콘크리트(UHPC, Ultra High Performance Concrete)는 기존의 콘크리트의 단점을 극복하기 위하여 강섬유 및 혼화재료를 사용하여 고강도화와 더불어 인장강도, 휨강도, 균열에 대한 저항성, 전단강도 및 내충격성을 대폭 개선시켜서 구조부재의 연성 및 강도를 확보하기 위해 개발된 것으로서 한국건설기술연구원이 독자적 연구를 바탕으로 UHPC를 개발하였고, KICT-UHPC의 특성을 충분히 반영한 보도사장교를 한국건설기술원내에 실구조물로 시공하였다. 한국건설기술연구원내 본관 1, 2동 연결 보도사장교(SUPER BRIDGE 1)의 진동실험을 통해 UHPC 보도사장교의 동특성(고유진동수 및 모드형상)을 평가하였다. 대상교량에는 보도사장교의 캔틸레버 구조 특성에 의해 발생하는 진동을 제어하기 위한 질량 264kg의 난간형 수직진동제어장치(TMD) 4대가 설치되어 있으며, 부가질량의 운동을 기계적으로 구속하거나 구속을 해제하여 TMD의 작동을 켜거나 끌 수 있도록 되어있다. TMD의 가동 및 정지시 동특성을 비교하는 정밀한 검증 실험을 통하여 TMD 설치에 의한 동특성의 변화도 평가하였다. 가진망치에 의한 충격실험으로부터 획득한 가속도 시간이력 데이터와 가진망치의 가진력 시간이력 데이터를 사용하여 주파수응답함수(FRF, frequency response function)를 계산하고, 이로부터 Super Bridge I의 동적모드형상과 고유진동수를 추출하였다. 1차 모드의 고유진동수는 TMD 정지시 2.2949 Hz, TMD 작동시 2.0996 Hz로서 8%정도 감소하였다. 충격해머에 의한 가진 실험을 통해 세계 최초로 시공한 UHPC 보도사장교의 진동특성과 관련한 신뢰성 있는 자료를 확보할 수 있었다.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.876-885
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• 2018

Utilization of spent RHDM(Residue Hydrodemetallation) catalyst as de-NOx SCR(Selective Catalytic Reduction) catalyst was studied by conducting by heptane cleaning and high-temperature roasting for removal of deposited carbon and sulfur. Followed by oxalic acid leaching was carried out for controlling excess vanadium deposited on spent RHDM catalyst in search of appropriate vanadium loadings for the best SCR performance and the leaching conditions are 5~15wt% concentration of oxalic acid and 5min leaching time at $50^{\circ}C$ with the ultra-sonic agitator. De-NOx activities of prepared and commercial SCR catalyst were measured by the atmospheric SCR catalyst performance test unit, their residual content were also carried out by ICP, C&S Analysis and XRF. Acid leaching (AL-10) catalyst showed the highest de-NOx efficiency of all prepared catalysts and the de-NOx efficiency over wash coated catalyst(WC-AL-10) was equivalent to that of commercial SCR catalyst. Therefore the possibility of using as SCR catalyst for each application by adjusting treatment conditions of spent RHDM catalyst was found and further research will be needed in detail for the its commercialization.

• Journal of Astronomy and Space Sciences
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• v.29 no.1
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• pp.33-40
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• 2012

Triplet Ionospheric Observatory (TRIO) CubeSatforIon, Neutral, Electron MAgneticfields (CINEMA) is a CubeSat with the weight 3 kg that will be operated in the orbit conditions of about 800 km altitude and $90^{\circ}$ inclination angle, using the S-band and ultra-high frequency (UHF)-band communication frequencies. Regarding the communication antenna loaded on the satellite, the two patch antennas has the downlink function in the S-band, whereas the two whip antennas has the function to receive the command sent by the ground station to the satellite in the UHF-band. The uplink ground station that communicates through the UHF-band with the CINEMA satellite was established at Kyung Hee University. The system is mainly composed of a terminal node controller, a transceiver, and a helical antenna. The gain of the helical antenna established at the Kyung Hee University ground station was 9.8 dBi. The output of the transceiver was set to be 5 W (6.9 dB) for the communication test. Through the far-field test of the established system, it was verified that the Roman characters, figures and symbols were converted into packets and transmitted to the satellite receiver in the communication speed of 9,600 bps.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.25-31
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• 2009

The anti-vibration tables that use air suspensions as dampers have been widely used due to their high anti-vibration performance in wide frequency band. However, they face a problem of easily accelerating the vibration when triggered by external force because their air suspensions have low rigidity and dampness. In response, there has been a study on active/semi-active dampers that use only the passive components like air suspensions to complement the passive-control format. Thus, we have dynamically analyzed the active/semi-active control of such passive anti-vibration tables. To demonstrate the anti-vibration table's control system, we have also constructed a kinetic model based on the physical characteristics of an anti-vibration table with 6 degrees of freedom and verified its applicability through analysis and experiments.

• Current Research on Agriculture and Life Sciences
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• v.30 no.1
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• pp.51-59
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• 2012

Fresh oyster mushrooms (Pleurotus ostreatus) were gamma-irradiated at 0, 1, 2, and 3 kGy. The effects on various quality attributes were determined during storage at $5{\pm}1^{\circ}C$. Color changes were more prominent in the cap region than the stem part. At the start of storage increase of Hunter's L-value (lightness) was observed in the caps of 2 and 3 kGy-irradiated samples. The L-value was higher in the all irradiated samples during storage. The trend was different in the case of stem region, where L-value decreased upon irradiation, but remained high throughout storage. The ${\alpha}$-value declined, whereas the b-value increased following irradiation. Irradiation showed a dose-dependent effect on the firmness, which was clearer during storage, but the samples irradiated at 1 kGy maintained an overall better texture than other irradiated samples. The weight loss was also higher in the all irradiated samples during storage. The samples irradiated at 1 kGy showed good physical appearance without any fungal attack at the end of storage; however color change in cap region was quite apparent. The ultra-structural drastic effect of irradiation was understandable using scanning electron microscopy. E-nose analysis demonstrated a clear change in the volatile profiles of all irradiated samples. Although the effect of irradiation on quality characteristics was quite clear but the all irradiated samples were free from fungal attack that was observed in the case of control sample.