• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1280-1285
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• 2000

The paper deals with a theoretical study on the vibrational characteristics of piezoelectric torsional transducers. The differential equations of piezoelectric torsional motion have been derived in terms of the circumferential displacement and the electric potential. Applying mechanical and electrical boundary conditions has yielded the characteristic equations of natural vibration in several transducer types. Numerical results have clarified the effect of the piezoelectric phenomenon on the mechanical resonance and the effect of the elastic block of a Langevin-type transducer on the natural frequency.

• 환경위생공학
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• 제17권1호
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• pp.41-51
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• 2002

This research was carried out using Anderson air sampler which were set up on the roof of the Engineering College of Konkuk University at Hwayang-Dong, Kwangjin-Gu, Seoul from Aug. 1992 to foul. 1999. The results are as follows: The major component of yellow sand is soil particles based upon the observation that particles ranging from $3.3~7.0{\mu}m$ occupy 36~63%. It is certain that the increase of fine particles of respirable dust during yellow sand phenomenon in Seoul area affects the human body. The trace metals from natural sources like Al, Ca, Fe, K, Na, and Si show larger mass median diameter(MMD) values during yellow sand phenomenon than in normal situations while the values of MMD for Mn and Pb rarely changes. Noticeably, the changes in value of MMD of water soluble elements like ${NO_3}^{-}$ and ${SO_4}^{2}$ are 2.3 and 6.6 times higher during the yellow sand phenomenon compared to normal situations, respectively. This fact is regarded as decisive evidence showing that ${NO_3}^{-}$ and ${SO_4}^{2}$ in the air are attached to yellow sand and move together.

• 문화기술의 융합
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• 제2권2호
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• pp.23-27
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• 2016

색청은 성장기에 프루닝이 정상적으로 이루어지지 않아서 시각이나 청각 경로에 혼선이 생긴 사람들에게 발생한다. 그들이 겪는 현상을 '색청'이라고 부른다 색청은 소리를 들을 때 색을 보는 형상을 말한다. 영상의 인터뷰에서 예술분야 전문가는 천부적인 재능으로 보았으며, 의학 분야 전문가는 일상생활에 큰 혼란을 야기하는 장애가 될 수 있다고 말한다. 일반적으로 사람들은 무의식적으로 공감각현상을 겪고 있다. 본 논문에서는 영상의 결과물을 바탕으로 과학적으로 증명된 연구결과와 일상 속의 현상을 바탕으로 '색청'을 분석하고, 또한 편집자의 관점에서 영상을 분석한다.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.554-564
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• 2022

The natural circulation phenomena occurring in fully integrated nuclear reactors are associated with a unique formation mechanism. The phenomenon results from a structural feature of these reactors involving upward flow from the core, located in the central-bottom region of a single vessel, and downward flow to the steam generator in the annulus region. In this study, to understand the natural circulation in a single vessel involving a multi-layered flow path, single-phase and two-phase natural circulation tests were performed using the SMART-ITL facility, and validation analysis of the TASS/SMR-S code was performed by comparing the corresponding test results. Three single-phase natural circulation tests were sequentially conducted at 15%, 10%, and 5% of full-scaled core-power without RCP operation, following which a two-phase natural circulation test was successively conducted with an artificial discharge of coolant inventory. The simulation capability of the TASS/SMR-S code with respect to the natural circulation phenomena was validated against the test results, and somewhat conservative but reasonably comparative results in terms of overall thermalhydraulic behavior were shown.

• Journal of Ginseng Research
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• 제26권2호
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• pp.89-95
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• 2002

인삼의 적변현상을 방제하기 위한 효율적인 방안을 마련하기 위한 본 연구의 결과를 요약하면 다음과 같다. 1. 천연자원으로부터 적변억제 효과가 우수한 방제물질 (Biotic preventers) ICPE-C$_{105}$과 ICPE-P$_{107}$을 선발하였다. 2 .적변방제 효과를 증진시키기 위해 선발한 보조제(AI) 중 "R"과 "W"가 우수하였다. 3. 방제물질과 보조제를 조합한 방제물질을 처리한 모든 처리구에서 인삼의 생장이 우수하였으며, 특히 ICPE-C$_{105}$R과 ICPE-P$_{107}$R의 처리구는 각각 67.3%, 52.7%의 생장 증가를 나타냈다. 4. 묘삼의 출아율은 ICPE-C$_{105}$P와 ICPE-P$_{107}$P 처리구에서 대조구보다 우수하였다. 5. 또한 방제물질 처리에 따른 적변발생율에서 대조구는 35%의 적변이 발생한 반면, ICPE-C$_{105}$R과 ICPE-P$_{107}$R이 5.3%의 적변발생율을 나타내어 적변에 효과가 있음을 확인하였다. 6. 인삼뿌리의 ginsenoside함량에 미치는 방제물질의 효과에서는 ICPE-C$_{105}$P와 ICPE-P$_{107}$R의 처리구가 각각 5.0%, 14.2%의 ginsenoside의 함량증가 효과가 있음을 확인하였다.

• 청정기술
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• 제10권4호
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• pp.203-213
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• 2004

천연가스의 열분해법은 천연가스 (CH4)를 고온에서 분해 시켜 수소와 탄소로 전환시키는 기술이다. 천연가스 열분해법의 가장 큰 장점은 이산화탄소의 발생 없이 수소와 탄소를 만드는 것이다. 본 연구에서는 이와같이 천연가스 고온 열분해법을 이용하여 메탄으로부터 수소와 탄소의 생성을 연구하였다. 실험을 통하여 메탄의 고온 열분해시 pyrocarbon이 반응관 내벽에 생성되며 그 위에 탄소가 퇴적되는 plugging 현상이 발생한다는 것을 알 수 있었다. 이 문제를 해결하기 위하여 본 연구에서는 이중관 반응기법, 반응 중간에 주기적으로 $O_2$나 $CO_2$로 퇴적된 탄소를 산화시키는 방법 등을 시도하였으며, 그 결과 어느 정도의 탄소 퇴적 현상을 해결할 수 있었다. 또한 SEM (Scanning Electron Microscope) image를 사용하여 탄소 입자의 크기를 측정하였으며 그 크기는 약 200 nm정도였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.410-411
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• 2006

On the continental margins and in permafrost regions, natural gas, which has been expected to replace petroleum energy, exists In solid hydrate farm. World hydrate reserves Including natural gas are estimated at about twice as much as the energy contained In total fossil fuel reserves. Because of its vast quantities, the efficient recovery of natural gas from natural gas hydrate becomes the most important factor on evaluating the economic feasibility in the sense of commercialization. It has been noted that carbon dioxide, one of the well-known green house gases, possibly can be stored in the ocean floor as a carbon dioxide hydrate. If the natural gas hydrate could be converted into carbon dioxide hydrate, natural gas hydrate deposits would serve as energy sources as well as carbon dioxide storage sites in the deep ocean sediments. In this study, we first attempted to examine the real swapping phenomenon occurring between guest molecules and various structures of gas hydrate through spectroscopic identification such as NMR spectroscopy.

• BMB Reports
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• 제28권3호
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• pp.238-242
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• 1995

The tadpole H-ferritin produced in E. coli was purified and its molecular properties were investigated to obtain information about the contribution of the H-subunit in the reaction of iron core formation. All the expressed subunits were assembled into complete holoprotein in vitro, presumably 24-mer, and the protein was heat-stable. Electron microscopy revealed that the recombinant ferritin forms spherically and contains iron core. No difference was observed in the absorption spectrum of the expressed protein compared to that of the natural ferritin. The Ouchterlony double diffusion of the expressed protein showed that the H-chain ferritin shares an antigenic determinant with natural tadpole ferritin. Rabbit anti-horse spleen ferritin discriminated the H-ferritin from natural ferritin. The rate of ferritin formation by the recombinant H-chain apoferritin was determined to be higher than that shown by natural tadpole ferritin, which consists of H, M and L-subunits. This phenomenon may be caused by the absence of M and L-subunits in the recombinant H-chain apoferritin.

• 한국태양에너지학회 논문집
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• 제40권1호
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• pp.35-47
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• 2020

Due to the large window area, the lighting environment of the educational space between the window and deep part of the room is not uniformly illuminated, and the phenomenon of glare is severe. For this reason, the daylight performance of DSC-BIPV windows was analyzed in order to improve the natural lighting in the educational sector. The method derives the correlation with natural lighting by measurement and simulation. Dynamic simulation confirmed that the average illuminance of the target space was higher at later than the early afternoon. The performance of natural lighting at 40% and 30% transmission of DSC has the effect of significantly reducing the amount of excess light in existing windows. Nevertheless, the actual average illuminance in all seasons corresponds to the standard illuminance of the educational facility, 300 Lux. In addition, the uniformity is also seen through the skylight illuminance ratio.

• 통합자연과학논문집
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• 제4권2호
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• pp.121-129
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• 2011

The purpose of this paper is to estimate the fluctuation of an earning rate and risk management using the price index of Korea stocks. After an observation of conception of fluctuation, we can show volatility clustering and fluctuation phenomenon in the Korea stock price index using GARCH model with heteroscedasticity. In addition, the effects of fluctuation on the time-series was evaluated, which showed the heteroscedasticity. MCMC method and Winbugs as Bayesian computation were used for analysis.