• 한국세라믹학회지
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• 제36권9호
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• pp.965-973
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• 1999

• 한국통신학회:학술대회논문집
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• 한국통신학회 1986년도 추계학술발표회 논문집
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• pp.20-22
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• 1986

This paper represents a graphical design technique of the symmetrical dielectric waveguids couplers. Once the phase constants are given by a approzimate model analysis, coupling lengths are easily calculated for each coupler. These method give some new insight of the codirectional couplers.

• Transactions on Electrical and Electronic Materials
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• 제13권4호
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• pp.196-199
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• 2012

CdS thin film was prepared on glass substrate by chemical bath deposition in an alkaline solution. The optical properties of CdS thin film were investigated using spectroscopic ellipsometry. The real (${\varepsilon}_1$) and imaginary (${\varepsilon}_2$) parts of the complex dielectric function ${\varepsilon}(E)={\varepsilon}_1(E)+i{\varepsilon}_2(E)$, the refractive index n(E), and the extinction coefficient k(E) of CdS thin film were obtained from spectroscopic ellipsometry. The normal-incidence reflectivity R(E) and absorption coefficient ${\alpha}(E)$ of CdS thin film were obtained using the refractive index and extinction coefficient. The critical points $E_0$ and $E_1$ of CdS thin film were shown in spectra of the dielectric function and optical constants of refractive index, extinction coefficient, normal-incidence reflectivity, and absorption coefficient. The dispersion of refractive index was analyzed by the Wemple-DiDomenico single-oscillator model.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.77-81
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• 2001

This paper proposed a novel chip type ceramic dielectric antenna by using the advanced meander line technique that the radiational metals are formed on the face of ceramic dielectric(8 ${\times}$ 4 ${\times}$ 1.5 mm, alumina) and both facses of substrate(1.0 mm thickness, FR-4). The performance of the antenna model has a good agreements between measurements and computed results. Resultly, it has a 10 dB return-loss bandwidth(2.4～2.4835 GHz) and 1.7 dBi measured radiation gain for Bluetooth application. The proposed antenna model can overcome the problems of the radiation gain from the small antenna's size.

• Journal of Advanced Marine Engineering and Technology
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• 제30권8호
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• pp.907-918
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• 2006

In this study capacitance and dielectric loss factor were measured with low-voltage signal and the simulation of equivalent circuits for the data was conducted. As the result it was shown that the equivalent circuit model considered the grain-boundary structure with semiconducting layer, dielectric layer and depletion layer was well approximated with the observed data. Various parameters were determined by a optimum curve-fitting method and could be used to analyze the characteristics of varistor. It also seems that the proposed equivalent circuit model will be adopted for other BL type varistors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1471-1473
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• 2000

In this study capacitance and dielectric loss factor were measured with low-voltage signal and the simulation of equivalent circuits for the data were conducted. As the result it was showed that the equivalent circuit model considered the gram-boundary structure with semiconducting layer, dielectric layer and depletion layer was well approximated with the observed data. Various parameters were determined by a optimum curve-fitting method and could be used to analyze the varistor-voltages and the nonlinear coefficient of varistors. It also seems that the proposed equivalent circuit model will be adopted for other BL type varistors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.6-8
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• 1995

In this paper, we study the computation of the electric field of dielectric analysis models with the conductivity on its surface. The finite element formulation describes a sinusoidal electrodynamic field computation. One term is added to this functional in order to take the conductivity on its surface into accounts. The electric field computations of the dielectric analysis model are done first with the surface conductivity and second with the volume conductivity. Also, it is shown that a surface conductor with sufficiently large conductivity can be substituted with a floating equipotential line. This method is applied to an insulator in arbitrary shape with the conductivity on its surface.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.527-528
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• 2012

플라즈마 유동제어를 통한 공기저항저감을 위해 DBD(Dielectric Barrier Discharge) 플라즈마 구동기를 설계하였고, 2D 시험모델의 풍동시험을 통해 항력저감을 측정하였다. 풍속이 없는 경우에는 유동박리 및 표면마찰저항이 존재하지 않으므로 플라즈마 유동제어를 통한 항력저감도 없었다. 2m/s의 풍속에서 유동박리제어를 통해 항력이 9.7%까지 감소됨을 확인하였으며, 풍속이 증가할수록 항력저감은 감소하였다.

• 대한전자공학회논문지SD
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• 제37권4호
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• pp.15-24
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• 2000

고유전 커패시터의 유전완화 특성은 시간영역에서 나타나는 커패시터의 동적특성으로 이해될 수 있으며 이것은 DRAM의 재충전 시간동안 충전된 전하를 잃어버리는 가장 주된 요인으로 인식된다. 그러므로 DRAM 동작에 미치는 영향을 고려하기 위하여 고유전 커패시터의 유전완화에 대한 등가회로를 만드는 것이 필수적이다. 그러나 아직까지 등가회로를 만들 수 있는 일반적이고 이론적인 방법이 제시되지 않고 있다. 근 본 연구에서는 고유전 커패시터의 등가회로를 주파수 영역에서 모델링하는 새로운 방법을 개발하였다. 이 방법은 이론적인 체계를 갖춘 일반적인 방법이다. 또한, 본 연구에서는 실험과정을 통해서 이 방법의 타당성으로 확인하였고, 궁극적으로 새로운 방법으로 얻어진 등가회로를 활용하여 유전완화가 DRAM 동작에 미치는 영향을 고찰하였다.

• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.656-662
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• 1998

To make a distinction between the influence of the dielectric constant and of methanol concentration on trypsin-catalyzed hydrolysis and methanolysis at $0^{\circ}C$, a model reaction of $N^u$-benzyloxycarbonyl-L-lysine p-nitrophenyl ester with water-methanol mixtures was chosen and a kinetic study done. The $k_{cat}$ values increased with methanol concentration, in a linear manner whereas $K_{M}$ values increased in a log-linear fashion. However, the $k_{cat},$_{M}$ ratio increased at lower methanol concentrations than 30% and then began to decrease at higher concentrations. The decrease in $k_{catK_M}$observed at higher than 30% methanol concentrations is attributed to the hydrophobic partitioning effect on substrate binding. On the other hand, the increase in $k_{catK_M}$ in the 0~30% methanol concentration range seems to be due to the effect of nucleophilic cosolvent on $k_{cat}$ and of the dielectric constant on $k_m$. This explanation was verified by measuring the effect of varying the dielectric constant of the medium on kinetic constants with isopropyl alcohol chemically unrelated to the enzyme reaction as the methanol concentration is maintained at a constant level. Therefore, we conclude that the effect of increasing the methanol concentration in the model reaction on the kinetic parameters $k_{cat \;and\;{K_M}}$ is caused by changes in both the nucleophilicity and the dielectric constant of the medium. Based on product analysis, the increase in $k_4, k_3$by decreasing the temperature can be accounted for by the suppression of hydrolytic reactions. This observation indicates that the nucleophile is favored by low temperatures. There was no loss of trypsin activity over a 10 h period in 60% methanol concentration at $pH^＊\; 5.5,\; 0^{\circ}C$.EX>.