• 대한생식의학회:학술대회논문집
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• 2007.11a
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• pp.112.2-113
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• 2007

• 대한생식의학회:학술대회논문집
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• 2006.11a
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• pp.153.1-153.1
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• 2006

• Proceedings of the Korean Magnestics Society Conference
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• 1994.03a
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• pp.36-37
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• 1994

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.322-323
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• 2001

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2002.02a
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• pp.40-40
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• 2002

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.183-193
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• 1995

Assuming that fishing nets are porous structures to suck water into their mouth and then filtrate water out of them, the flow resistance N of nets with wall area S under the velicity v was taken by $R=kSv^2$, and the coefficient k was derived as $$k=c\;Re^{-m}(\frac{S_n}{S_m})n(\frac{S_n}{S})$$ where $R_e$ is the Reynolds' number, $S_m$ the area of net mouth, $S_n$ the total area of net projected to the plane perpendicular to the water flow. Then, the propriety of the above equation and the values of c, m and n were investigated by the experimental results on plane nettings carried out hitherto. The value of c and m were fixed respectively by $240(kg\cdot sec^2/m^4)$ and 0.1 when the representative size on $R_e$ was taken by the ratio k of the volume of bars to the area of meshes, i. e., $$\lambda={\frac{\pi\;d^2}{21\;sin\;2\varphi}$$ where d is the diameter of bars, 21 the mesh size, and 2n the angle between two adjacent bars. The value of n was larger than 1.0 as 1.2 because the wakes occurring at the knots and bars increased the resistance by obstructing the filtration of water through the meshes. In case in which the influence of $R_e$ was negligible, the value of $cR_e\;^{-m}$ became a constant distinguished by the regions of the attack angle $ \theta$ of nettings to the water flow, i. e., 100$(kg\cdot sec^2/m^4)\;in\;45^{\circ}<\theta \leq90^{\circ}\;and\;100(S_m/S)^{0.6}\;(kg\cdot sec^2/m^4)\;in\;0^{\circ}<\theta \leq45^{\circ}$. Thus, the coefficient $k(kg\cdot sec^2/m^4)$ of plane nettings could be obtained by utilizing the above values with $S_m\;and\;S_n$ given respectively by $$S_m=S\;sin\theta$$ and $$S_n=\frac{d}{I}\;\cdot\;\frac{\sqrt{1-cos^2\varphi cos^2\theta}} {sin\varphi\;cos\varphi} \cdot S$$ But, on the occasion of $\theta=0^{\circ}$ k was decided by the roughness of netting surface and so expressed as $$k=9(\frac{d}{I\;cos\varphi})^{0.8}$$ In these results, however, the values of c and m were regarded to be not sufficiently exact because they were obtained from insufficient data and the actual nets had no use for k at $\theta=0^{\circ}$. Therefore, the exact expression of $k(kg\cdotsec^2/m^4)$, for actual nets could De made in the case of no influence of $R_e$ as follows; $$k=100(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})\;.\;for\;45^{\circ}<\theta \leq90^{\circ}$$, $$k=100(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})^{1.6}\;.\;for\;0^{\circ}<\theta \leq45^{\circ}$$

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.45-45
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• 2009

우리는 ZnO Template를 사용한 열기상법을 이용하여 수직 배양한 ZnO nanorods와 ZnO Nanopencils를 성장하였고, Dependency temperature Photoluminescence(PL)의 분석을 통하여 광학적 특성에 대해 분석을 하였다. ZnO 나노구조는 100K 이하의 온도에서 donor-bound exciton가 dominant하고, 100K 이상의 온도에서는 free exciton과 그들의 phonon-replica emission이 dominant한 것을 알 수 있었다. 하지만, ZnO nanorods와 nanopencils은 다른 exciton-phonon coupling의 strength에 의한 surface defects에 의해 excitonic emissions의 다른 거동을 보이는 것을 알았다. 이것으로 인해 상온 PL에서 ZnO nanopencil은 nanorods에 비해 52meV의 red shift를 보였다.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.294-296
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• 2003

본 논문에서는 우리나라 7개 지역의 시송전 선로를 구성하여 전력계통안정화장치(Power System Stabilizer)의 특성을 분석한다. Black start 발전기의 전력은 각 지역의 시송전 경로를 통하여 우선공급발전기에 공급한다. 이는 한국전력거래소(KPX)에서 규정하고 있으며, 주선로와 예비선로로 구성되어 있다. PSS의 성능 분석은 PSS1A type을 부착하여 수행하였다. 시뮬레이션 패키지는 EMTDC를 사용하여 그 특성을 검토하였다.

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.69-69
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• 2003

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.393-397
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• 2012

We report a new route to synthesize high quality zinc blende CdS and ZnS nanocrystals in noncoordinating solvent 1-octadecene, using dodecanethiol (DDT) molecules as both the sulfur source and surface capping ligands. Different reaction temperatures and Cd(Zn)/DDT molar ratios were tested to optimize the synthesis conditions. Absorption photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) pattern, and transmission electron microscopy (TEM) were used to characterize assynthesized nanocrystals. The narrow half width at the half-maximum on the long wavelength side of the firstexcitonic absorption peak and TEM images demonstrated nearly monodisperse size distributions of asprepared CdS, ZnS, and CdS/ZnS core/shell nanocrystals. Only trap emissions of the nanocrystals were detected when the amount of DDT was excessive, this came from the strong quenching effect of thiol groups on the nanocrystal surfaces. After overcoating with ZnS shells, band-gap emissions of CdS nanocrystals were partially recovered.