• 대한치과보철학회:학술대회논문집
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• 2002.11a
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• pp.124-125
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• 2002

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2888-2898
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• 2021

Vital area identification (VAI) is an essential procedure for the design of physical protection systems (PPSs) for nuclear power plants (NPPs). The purpose of PPS design is to protect vital areas. VAI has been improved continuously to overcome the shortcomings of previous VAI generations. In first-generation VAI, a sabotage fault tree was developed directly without reusing probabilistic safety assessment (PSA) results or information. In second-generation VAI, VAI model was constructed from all PSA event trees and fault trees. While in third-generation VAI, it was developed from the simplified PSA event trees and fault trees. While VAIs have been performed for NPPs in full-power operations, VAI for NPPs in low-power and shutdown (LPSD) operations has not been studied and performed, even though NPPs in LPSD operations are very vulnerable to sabotage due to the very crowded nature of NPP maintenance. This study is the first to research and apply VAI to LPSD operation of NPP. Here, the third-generation VAI method for full-power operation of NPP was adapted to the VAI of LPSD operation. In this study, LPSD VAI for a few plant operational states (POSs) was performed. Furthermore, the operation strategy of vital areas for both full-power and LPSD operations was discussed. The LPSD VAI method discussed in this paper can be easily applied to all POSs. The method and insights in this study can be important for future LPSD VAI that reflects various LPSD operational states. Regulatory bodies and electric utilities can take advantage of this LPSD VAI method.

• Journal of Conservation Science
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• v.23
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• pp.1-10
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• 2008

Consolidants based on tetraethoxysilane (TEOS) such as alkoxysilanes have been widely used for the consolidation of decaying stone heritages. Low-viscosity alkoxysilanes penetrate inside the decaying stone and polymerize within the porous structure of the decaying stone, significantly increasing the cohesion of the material. However, TEOS-based consolidants suffer from practical drawbacks, such as crack formation of the gel during the drying phase due to the developed capillary force, which is typical for TEOS-based consolidants. We prepared new consolidants TEOS-based consolidants containing flexible (3-glycidoxypropyl)trimethoxysilane (GPTMS) and silica nanoparticles (or polyhedral oligomeric silsesquioxanes (POSS)) in order to reduce capillary force development during gel drying. Since the consolidants should have a good interaction with the component of the stone in order to connect the isolate grains of decaying stone, the adhesion interaction of the developed consolidants on the surface of the granite was macroscopically investigated by the ISO 2409 cross cutting test. The adhesion interaction decreased with the addition of silica nanoparticle and POSS while it increased with the addition of GPTMS in TEOS solution.

• Journal of the Korean institute of surface engineering
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• v.39 no.3
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• pp.93-97
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• 2006

Polymer light emitting diodes (PLEDs) are expected to be commercialized as next generation displays by advantages of the fast response time, low driving voltage and easy manufacturing process for large sized flexible display. Generally, the electrical and optical properties of PLEDs are affected by the surface conditions of transparent electrode. The PLED devices with ITO/PEDOT:PSS/PVK/PFO-poss/LiF/Al structures were prepared by using the spin coating method. For this, PEDOT:PSS(poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)) Al 4083 and PVK(N-vinylcabozole) were used as hole injection and transport layers. The PFO-poss(poly(9,9-dioctylfluorene)) was used as the emitting layer. The dependence of $O_2$ plasma treatment of ITO electrode on the electrical and optical properties of PLEDs were investigated. The sheet resistances increased slightly with an improved surface roughness of ITO electrode as the RF power increased during $O_2$ plasma treatment. The PLED devices prepared on the ITO/Glass substrates, which were plasma-treated at 40 watt in RF power for 30 seconds under 40 mtorr $O_2$ pressure, showed the maximum external emission efficiency of 0.86 lm/W and the maximum luminance of $250\;cd/m^2$, respectively. The CIE color coordinates are ranged $X\;=\;0.13{\sim}0.18$ and $Y\;=\;0.10{\sim}0.16$, showing blue color. emission.

• Macromolecular Research
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• v.17 no.5
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• pp.352-355
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• 2009

• Mycobiology
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• v.28 no.1
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• pp.39-46
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• 2000

Eight species of Marssonina parasitic on 21 species of host plants from Korea are described and illustrated. They are Marssonina brunnea (Ellis & Everh.) Magnus, M. capsulicola (Rostr.) Magnus, M. celastri H.D. Shin & H.T. Lee, M. coronaria (Ellis & Davis) Davis, M. fragariae (Lib.) Kleb., M. juglandis (Lib.) Magnus, M. rosae (Lib.) Died. and M. sennenis (Gonz. Frag.) Vassiljevsky & Karak. Of these, M. capsulicola and M. coronaria sometimes poss three-celled conidia and M. sennenis is characterized by a short appendage at the basal end of the conidia. Morphological features of conidia and host ranges were of taxonomic values for species delimitation.

• Journal of The Korean Astronomical Society
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• v.24 no.1
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• pp.107-116
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• 1991

With a modern microdensitometer and POSS glass copies, we have performed an automated star counting in two colors, blue and red, over the region containing Bok globule B361. Distribution of the measured extinction values over the projected angular distance from the cloud center was approximated by a power-law, and the resulting power-law indices for the blue and red are shown to be distinctly different from each other. The difference in the power-law index indicates that the mean dust size increases towards the cloud center. Possible physical causes for such size variation are briefly discussed.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.133-134
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• 2006

본 논문에서는 ITO/Glass 기판에 스핀 코팅법(Spin Coating)과 열 증착법(Thermal Evaporation)을 이용하여 ITO/PEDOT:PSS/PVK/PFO-poss/Li/Al 구조를 갖는 청색 고분자 유기전계발광소자를 제작하였다. 청색 고분자 유기발광다이오드 제작시 ITO 전극을 $O_2$ gas를 이용한 Plasma Treatment와 Heat Treatment를 실시하여 기판처리가 제작된 소자의 전기, 광학적 특성에 미치는 영향에 대하여 조사하였다. Plasma와 Heat Treatment를 동시에 처리한 소자에서 가장 우수한 전기, 광학적 특성을 나타냈으며, 기판처리를 하지 않은 경우는 전기, 광학적 특성은 크게 감소하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.89-90
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• 2007

본 연구에서는 ITO/PEDOT:PSS/PFO-poss/LiF/Al 구조를 갖는 고분자 유기발광다이오드(PLED)를 제작하여 ITO 투명 전도막의 전처리 효과가 유기발광 다이오드의 특성에 미치는 영향에 대하여 조사하였다. 최적의 전처리 조건을 찾기 위하여 다양한 플라즈마 처리 조건에 다른 ITO 투명전도막의 표면형상의 변화와 전기적 특성을 관찰하였다. 또한 ITO 투명전도막에 플라즈마 처리와 열처리를 실시하여 PLED 소자를 제작하고 전기 광학적 특성을 조사하여 ITO 투명 전도막의 전처리가 소자의 특성에 미치는 영향을 조사하였다.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.596-607
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• 2012

The R-Z relationship is one of important error factors to determine the accuracy of radar rainfall estimation. In this study, we have explored the effect of the R-Z relationships derived from disdrometer data in estimating the radar rainfall. The heavy rain event that produced flooding in St-Remi, Quebec, Canada has been occurred. We have tried to investigate the severity of rain for this event using high temporal (2.5 min) and spatial resolution ($1^{\circ}$ by 250 m) radar data obtained from the McGill S-band radar. Radar data revealed that the heavy rain cells pass directly over St-Remi while the coarse raingauge network was not sufficient to detect this rain event. The maximum 30 min (1 h) accumulation reaches about 39 (42) mm in St-Remi. During the rain event, the two disdrometers (POSS; Precipitation Occurrence Sensor System) were available: One used for the reflectivity calibration by comparing disdrometer Z and radar Z and the other for deriving disdrometric R-Z relationships. The result shows the significant improvement with the disdrometric reflectivity-dependent R-Z relationships against the climatological R-Z relationship. The bias in radar rain estimation is reduced from +12% to -2% and the root-mean squared error from 16 to 10% for daily accumulation. Using the estimated radar rainfall rate with disdrometric R-Z relationships, the flood event was well captured with proper timing and amount.