• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.658-666
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• 2003

In this paper, we analyzed standard and characteristic of portable microwave digital FPU(Field Pick Up) transmission system in AWGN channel environment as basis step of research about share way of M/W broadcasting relay frequency. And we analyzed system performance through simulator design. Domestic case, digitize progress about broadcasting relay is propeled. Therefore, we wish to utilize to basis data about interference evaluation and domestic broadcasting relay standardization for reassignment of M/W band broadcasting relay frequency.

• Journal of Korean Society for Atmospheric Environment
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• v.3 no.1
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• pp.1-12
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• 1987

A series of supported sulfided Ni-W/$\gamma-Al_2O_3$ and Co-W/$\gamma-Al_2O_3$ catalysts with different nickel and cobalt contents were studied in the hydrodenitrogenation of pyridine dissolved in n-heptane. The ranges of experimental conditions were at the temperatures between 453 and 753 K, and the pressures between 30 and 50 Bar. The catalytic activities with different nickel and cobalt contents were shown to be maximum at Ni/Ni+W = 0.2 - 0.3, Co/Co+W = 0.3 - 0.4. Pyridine conversion increased with pressure and temperature and the step of piperidine formation was found to be irreversible. The reaction orders in Ni-W/$\gamma-Al_2O_3$ and Co-W/$\gamma-Al_2O_3$ catalysts were the first with respect to pyridine and reaction rate constants decreased with increase of initial pyridine concentration and their activation energies were 12.98 and 9.23 kcal/mol, respectively.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.121-122
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• 2008

The films of the vanadium tungsten oxide, $V_{1.85}W_{0.15}O_5$, were grown on Pt/Ti/$SiO_2$/Si substrate by RF sputtering method. It was found that film crystallinity, dielectric properties, and TCR properties were strongly dependent upon the thin film thickness. As increasing of $V_{1.85}W_{0.15}O_5$ thickness, the grain size, morphology, and crystallinity increased. The dielectric constants of $V_{1.85}W_{0.15}O_5$ thin films deposited at 150nm were 71.11, with a dielectric loss of 0.015, respectively. Also, The $V_{1.85}W_{0.15}O_5$ thin films showed good TCR values of -3.45%/K.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.151-154
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• 2013

본 논문에서는 전관방송 시스템에 사용되는 전관방송용 파워앰프에 대해 TTA에서 개발한 시험규격을 설명하고, 주요 시험항목에 대해 출력 레벨에 따라 어떠한 특성이 나타나는지 시험 결과를 분석하였다. 시험을 위해 현재 상용으로 판매되는 정격출력이 260 W, 360 W, 480 W, 600 W 인 앰프를 사용하였고, 각각의 앰프에 대해 정격출력, 1/2 정격, 1/4 정격, 1/8 정격, 10W, 1W 일 때 주파수 응답, 신호대잡음비, THD+N 비를 측정하여 비교하였다. 향후 본 논문의 시험 데이타가 전관방송용 앰프의 성능을 가늠할 때 중요 지표가 될 것으로 기대한다.

• Journal of Pharmaceutical Investigation
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• v.28 no.3
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• pp.159-164
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• 1998

The O/W and W/O emulsions containing Scutellariae Radix extract(SRE) which is very slightly soluble in oil phases and sparingly soluble in water phases, were prepared by homogenizing water and oil phases with emulsifier. The diameters of emulsion were ranged from 100 to $300\;{\mu}m$. The viscosity of W/O emulsion was higher than that of O/W emulsion. W/O emulsion was more stable than O/W emulsion which was gradually degraded when tested by centrifuge method and temperature tolerance method at $50^{\circ}C$. The antibacterial activity of two emulsions was not significantly different from that of aqueous solution of SRE, and showed similar MIC and bacterial growth inhibition rate.

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.1
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• pp.1-11
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• 2002

Physical properties of PVB [Poly(vinyl butyral)] polymer are strongly correlated with water contents in the polymer. Thus dynamics of PVB containing 10~50(w/w) ％ of water were studied by $^{13}$ C CP/MAS/DD over the temperature range 293K -348K. From the Peak area, line width, chemical shift, and relaxation times ( $T_{1}$ $T_{1p}$) measured at 9.4 T, it was deduced that water facilitates molecular dynamics of the PVB molecules overall including conformational exchange of the racemic and meso butyaldehyde rings in the PVB. However, the influence of water was not linear to the amount of water in the PVB samples. It is suggested that water up to 30 w/w ％ of the sample is closely bound to the PVB polymer and water relatively free from the PVB polymer starts to appear when water is added more than 30 w/w ％.％.

• Journal of the Korean Mathematical Society
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• v.45 no.3
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• pp.771-780
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• 2008

Let $M_C=\(\array{A&C\\0&B}\)$ be a $2{\times}2$ upper triangular operator matrix acting on the Hilbert space $H{\bigoplus}K\;and\;let\;{\sigma}_w(\cdot)$ denote the Weyl spectrum. We give the necessary and sufficient conditions for operators A and B which ${\sigma}_w\(\array{A&C\\0&B}\)={\sigma}_w\(\array{A&C\\0&B}\)\;or\;{\sigma}_w\(\array{A&C\\0&B}\)={\sigma}_w(A){\cup}{\sigma}_w(B)$ holds for every $C{\in}B(K,\;H)$. We also study the Weyl's theorem for operator matrices.

• Journal of the Korean Mathematical Society
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• v.55 no.3
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• pp.671-694
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• 2018

In this paper, we investigate the weighted vector-valued bounds for a class of multilinear singular integral operators, and its commutators, from $L^{p_1}(l^{q_1};\;{\mathbb{R}}^n,\;w_1){\times}{\cdots}{\times}L^{p_m}(l^{q_m};\;{\mathbb{R}}^n,\;w_m)$ to $L^p(l^q;\;{\mathbb{R}}^n,\;{\nu}_{\vec{w}})$, with $p_1,{\cdots},p_m$, $q_1,{\cdots},q_m{\in}(1,\;{\infty})$, $1/p=1/p_1+{\cdots}+1/p_m$, $1/q=1/q_1+{\cdots}+1/q_m$ and ${\vec{w}}=(w_1,{\cdots},w_m)$ a multiple $A_{\vec{P}}$ weights. Our argument also leads to the weighted weak type endpoint estimates for the commutators. As applications, we obtain some new weighted estimates for the $Calder{\acute{o}}n$ commutator.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.455-458
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• 2006

The S/W error is in the S/W from the development stage other than H/W, and it may come out when the specific function is necessary. The S/W failure may happen due to these errors. I analyze causes of the fault detected during testing stage and operational stage, and fgailure caused by it. And then, I analyze which case of testing stage and operational stage is much severe than the other case by real failure data acquisition.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.101-108
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• 2006

This paper describes the design, fabrication, and measured results of a W-band Cassegrain antenna suitable for the target detecting fuze sensor. The Cassegrain antenna is designed using MATLAB and MWS of CST. We use the multi-mode horn antenna as a feeder. The measurement results are as follows: The gain is about 41dB; SLL is 17.7dB; 3dB beamwidth is about $1.51^{\circ}$ in E-plane and $1.45^{\circ}$ in H-plane. The magnitude of leakage signals is about 43.5mVpp when the fabricated antenna and the transceiver of the fuze sensor ire combined. As a result, the designed W-band Cassegrain antenna could be quite applicable to the target detecting fuze sensor.