• 한국초전도학회:학술대회논문집
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• v.9
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• pp.343-347
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• 1999

We fabricated a resistive SFCL having a shunt resistor parallel to it in order to bifurcate the transient current at faults. The SFCL consists of a YBCO film coated with an Au layer (10 ${\omega}$ at room temperature), which is to disperse the heat generated at hot spots in the YBCO film, and the 5 ${\omega}$ shunt resistor. The minimum quench current of the SFCL was found to be 12.2 A$_{peak}$. This SFCL successfully controlled the fault current below 23 A$_{peak}$ which is otherwise to increase up to 113 A$_{peak}$. Bifurcation of the current resulted in the temperature rise of the YBCO/Au film 3 times slower than without the shunt, protecting the SFCL at high currents.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.1
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• pp.18-25
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• 2013

Assessment and validation of RANS turbulence models are conducted for the optimal analysis of supersonic converging-diverging nozzle through the comparison between computational results and experimental data. One/two equation turbulence closures such as Spalart-Allmaras, RNG k-${\varepsilon}$, and k-${\omega}$ SST are employed to simulate the two-dimensional nozzle flow. Computational results with the turbulence models mentioned fairly well predict shock structure of the nozzle-inside and pressure distribution along the wall. Especially, SST model among the employed ones shows the best agreement to experimental results.

• Journal of the Korean Mathematical Society
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• v.32 no.4
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• pp.815-834
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• 1995

Let $\Omega$ be a rectangular domain in $R^2$ with boundary $\partial\Omega$, and T be a positive real number such that $0 < T < \infty$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.1014-1017
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• 2012

In this paper, we introduce a method which enhances the azimuth resolution to obtain the high-resolution SAR image. We used ${\omega}-k$ algorithm to obtain the SAR image and extrapolation using auto-regressive(AR) method to enhance the azimuth resolution in the 2-D frequency domain. The AR method is a linear prediction model-based extrapolation technique. In the result, we showed the performance comparison with respect to the target range and the prediction order of Burg algorithm which is one of AR method.

• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.277-284
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• 2011

The compositions of health functional food products (HFFP; 18 products) containing gamma linolenic acid (GLA; $C_{18:3}$, n-6) and omega-3 fatty acids (EPA and DHA) were investigated. The contents of index components (especially, GLA and omega-3) in HFFPs were monitored by GC-FID analysis. Among the GLA products (sample No. 1~8), the content of GLA in most samples (except sample No.6) ranged from 8.04 to 9.98 g/100 g. These results were suitable for the reference standard (more 7.0 g/100 g) of HFF. In the omega-3 products (sample No. 10 and 15) derived from harp seal oil (HSO), the total contents of EPA and DHA were 14.21-15.98 g/100 g, respectively. These values were suitable for the reference standard (more 12.0 g/100 g) of HFF. Besides, among the omega-3 products (sample No.9, 11~14, 16~18) derived from fish oil, the total content of EPA and DHA ranged from 24.11 to 31.20 g/100 g. These results were suitable for the reference standard (more 18.0 g/100 g) of HFF. In the result of TLC analysis, the HFFPs of 18 were mainly composed of triacylglycerols (TAGs). The content of trans fatty acid in 18 HFFPs was detected in less than 0.30 g/100 g. For the detection of trans fatty acid, $^1H$-NMR (600 MHz) can be used because chemical shift of trans fatty acid was observed at 5.3 ppm in this study.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.138-143
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• 1997

Acid-catalyzed hydrolysis of 3,3-bis(methylthio)-2-propen-1-phenyl-1-one derivatives were studied kinetically in concentrated aqueous hydroperchloric acid(-Ho < 2.23) at $30^{\circ}C.$ The substituent effect, analysis of hydrolysis product, hydration $parameter({\omega} & {\phi}$) from the Bunnett equation and the Bunnett-Olsen equation on the rate indicate that the acid-catalyzed hydrolysis of the substrates below 3.8 M hydroperchloric acid media occurs through A-1 type reaction($3.3 >{\omega},\;0.58 >{\phi} & {\rho}< 0$) mechanism and above 3.8 M hydroperchloric acid, the reaction proceeds A-2 type reaction($0 <(\omega)$, $0 <{\phi} & (\rho)> 0$) mechanism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.197-200
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• 2001

In this letter, we report on the investigation of Ni/Si/Ni Ohmic contacts to n-type 4H-SiC. Ohmic contacts have been formed by a vacuum annealing and $N_2$ gas ambient annealing method at $950^{\circ}C$ for 10 min. The specific contact resistivity ( $\rho_{c}$ ), sheet resistance($R_s$), contact resistance($R_c$), transfer length($L_T$) were calculated from resistance($R_T$) versus contact spacing(d) measurements obtained from 10 TLM(transmission line method) structures. The resulting average values of vacuum annealing sample were $\rho_{c}=3.8{\times}10^{-5}\Omega cm^{3}$, $R_{c}=4.9{\Omega}$, $R_{T}=9.8{\Omega}$ and $L_{T}=15.5{\mu}m$, resulting average values of another sample were $\rho_{c}=2.29{\times}10^{-4}\Omega cm^{3}$, $R_{c}=12.9{\Omega}$ and $R_{T}=25.8{\Omega}$. The physical properties of contacts were examined using X-Ray Diffraction and Auger analysis, there was a uniform intermixing of the Si and Ni, migration of Ni into the SiC.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.458-458
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• 2013

We investigated a study on the thermal degradation of boron doped zinc-oxide (BZO) layer which used as a transparent conducting layer on the Cu (In1-xGax) Se2 (CIGS) based thin film solar cells. Devices were annealed under the temperature of $100^{\circ}C$ or 100 hours and then Hall measurement was carried out to characterize the parameters of mobility (${\mu}Hall$), resistivity (${\rho}$), conductivity (${\sigma}$) and sheet resistance (Rsh). The initial values of ${\mu}Hall$, ${\rho}$, ${\sigma}$ and Rsh were $29.3cm^2$/$V{\cdot}s$, $2.1{\times}10^{-3}{\Omega}{\cdot}cm$, $476.4{\Omega}^{-1}{\cdot}cm^{-1}$ and $19.1{\Omega}$/${\Box}$ respectively. After the annealing process, the values were $4.5cm^2$/$V{\cdot}s$, $12.8{\times}10^{-3}{\Omega}{\cdot}cm$, $77.9{\Omega}^{-1}{\cdot}cm^{-1}$ and $116.6{\Omega}$/${\Box}$ respectively. We observed that ${\mu}Hall$ and ${\sigma}$ were decreased, and ${\rho}$ and Rsh were increased. In this study, BZO layer plays an important role of conducting path for electrons generated by incident light onthe CIGS absorption layer. Therefore, the degradation of BZO layer characterized by the parameters of ${\mu}Hall$, ${\rho}$, ${\sigma}$ and Rsh, affect to the cell efficiency.

• Journal of the Korean Mathematical Society
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• v.54 no.3
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• pp.713-732
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• 2017

Let ${\Omega}{\in}L^s(S^{n-1})$ for s > 1 be a homogeneous function of degree zero and b be BMO functions or Lipschitz functions. In this paper, we obtain some boundedness of the $Calder{\acute{o}}n$-Zygmund singular integral operator $T_{\Omega}$ and its commutator [b, $T_{\Omega}$] on Herz-type Hardy spaces with variable exponent.

• Journal of the Korean Mathematical Society
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• v.44 no.6
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• pp.1255-1266
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• 2007

We establish a weighted norm inequality for a class of rough parametric Marcinkiewicz integral operators $\mathcal{M}^{\rho}_{\Omega}$. As an application of this inequality, we obtain weighted $L^p$ inequalities for a class of parametric Marcinkiewicz integral operators $\mathcal{M}^{*,\rho}_{\Omega,\lambda}\;and\;\mathcal{M}^{\rho}_{\Omega,S}$ related to the Littlewood-Paley $g^*_{\lambda}-function$ and the area integral S, respectively.