• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 추계학술대회 논문집
• /
• pp.397-400
• /
• 1996

We investigated electric and dielectric properties of MIM device using Maleate Copolymer LB films. The thickness of maleate copolymer LB film by ellipsometry measurements and X-ray diffraction pattern was about 27~30[ ]. The maleate copolymer 13 film have the property of insulator like organic ultra-thin film. The electric conduction was Schottky current measured by I-V characteristics, and the conductivity was 10$^{-15}$ ~10$^{-14}$ [S/cm]. Dielectric constant was about 5.0~6.0 by various measurement: I-V, frequency-depenent dielectric properties. Schottky barrier was about 0.9 ~1.0(eV). By relation between log I and 1/T, activation energy baa 0.74(eV). Frequency-depenent dielectric properties wart orientational polarization by the dipole.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
• /
• pp.84-87
• /
• 2001

In this paper, degradation and dielectric properties of XLPE sheets moved from 22/154kV power cables were investigated. At the results of dielectric property of 22kV/154kV XLPE sheet, We earned that $tan{\delta}$ is $7.4{\times}10^{-4}$, $2.15{\times}10^{-4}$ and dielectric constant is 2.3, 2.24. Temperature dependance of $tan{\delta}$ inclined to increasing with temperature and increase of $tan{\delta}$ of 22kV XLPE sheet is higher than it of 154kV XLPE sheet. And increasement of XLPE sheet with water is higher than it without water.

• 한국전기전자재료학회논문지
• /
• 제11권10호
• /
• pp.773-777
• /
• 1998

This paper presents the results of measured permittivity of PCB sheet material in the frequency range of 0.1 ~ 2[㎓] and temperature range of 25~ 85[>$^{\circ}C$]. Microstrip lines with different physical length are implemented to measure the attenuation and phase shift of the signals through these lines. The loss factor of glass-epoxy and teflon could by calculated with the measured dielectric constant and the attenuation. From the experiment, the glass-epoxy was more influenced by temperature and frequency than teflon. The average dielectric constants of glass-epoxy and teflon within the measured frequency range are 4.48 and 2.18, respectively.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.229-229
• /
• 2007

In this study, HEMA-based hydrophilic copolymers were synthesized and dielectric constant (K) of the polymer thin films were investigated by change hydroxyl group (-OH) ratio in the polymer chain. The different hydroxyl group ratios were characterized by FT-IR and its thin films were obtained by spin coating. As a result, due to the moisture absorption of the hydrophilic thin film, the dielectric constant has been increased as was expected. The highest dielectric constant (K=4.19, @1MHz) was observed at 40% hydroxyl group ratio among the several polymers.

• 한국결정학회:학술대회논문집
• /
• 한국결정학회 2000년도 정기총회 및 구정회교수 추모 춘계학술연구발표회
• /
• pp.28-28
• /
• 2000

• 한국결정성장학회지
• /
• 제20권6호
• /
• pp.249-253
• /
• 2010

A-자리 경함 perovskite $La_{1/3}NbO_3$ 단결정 시편을 제작하여 10~800 K 온도범위에서 유전특성을 조사하였다. 50 K와 650 K 부근에서 유전이상이 나타났으며, 고온영역(약 650 K)에서 유전상수의 thermal hysterisis가 크게 나타났다. 교류전도도 측정으로부터 560~690 K에서 입내 활성화 에너지는 0.43 eV로 가장 낮게 나타났다. 이들의 결과로부터 50 K 부근의 dielectric anomaly는 $Nb^{5+}$-이온의 antiparallel 변위에 기인한 것이며, 650 K 부근의 dielectric anomaly는 $La^{3+}$-이온의 재배열에 기인한 것으로 추측된다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.36-38
• /
• 2005

This study is about how to lower the driving voltage that enables to move the micro droplet by the EWOD (Electro Wetting On Dielectric) mechanism. EWOD is well known that it is used ${\mu}-TAS$ digital micro fluidics system. As the device which is fabricated with dielectric layer between electrode and micro droplet is applied voltage, the hydrophobic surface is changed into the hydrophilic surface by electrical property. Therefore, EWOD induces the movement of micro droplet with reducing contact angle of micro droplet. The driving voltage was depended on the dielectric constant of dielectric layer, thus it can be reduced by increase of dielectric constant. Typically, very high voltage ($100V{\sim}$) is used to move the micro droplet. In previous study, we used $Ta_{2}O_{5}$ as the dielectric layer and driving voltage was 23V that reduced 24 percent compared with $SiO_2$. In this study, we used $BZN(Bi_{2}O_{3}ZnO-Nb_{2}O_{5})$ layer which had high dielectric constant. It was operated the just 12V. And micro droplet was moved within Is on 15V. It was reduced the voltage until 35 percents compare with $Ta_{2}O_{5}$ and 50 percents compare with $SiO_2$. The movement of micro droplet within 1s was achieved with BZN (ferroelectrics)just on 15V.

• 한국분말재료학회지
• /
• 제16권1호
• /
• pp.37-42
• /
• 2009

In this study, the feasible test for the mechanical property characterization of $BaTiO_3$ ceramics and multi-layer ceramic capacitor(MLCC) was performed with nanoindentation technique. In case of $BaTiO_3$ ceramics, hardness and elastic modulus are dependent on the densification of specimen showing the highest hardness and elastic modulus values of 12.3 GPa and 155 GPa, respectively at $1260^{\circ}C$. In case of MLCC chip, hardness of dielectric layer was lower than that of margin region. The nanoindentation method could be useful tool for the measurement of mechanical property within $BaTiO_3$ dielectric layer of very thin thickness in high capacitance MLCC.

• 대한기계학회논문집B
• /
• 제27권5호
• /
• pp.543-552
• /
• 2003

The effects of a directionally emitting and reflecting dielectric surface on the wall heat flux and medium temperature distribution are studied. The system is an infinite square duct enclosing an absorbing and emitting medium. The emissivity and reflectivity of opaque and gray wall vary with direction. Combined effect of conductive and radiative heat transfer is analyzed using finite difference and the direct discrete-ordinates method. The parameters under study are conduction to radiation parameter, optical depth, refractive index ratio. The results with directional and diffuse properties deviate each other when the conduction to radiation parameter is less than around 0.01. The wall heat flux differs fur optical thickness less than around 0.1. However, the medium temperature profiles differ for optical thickness greater than around 1. Deviations from diffuse property calculations are larger for hot wall with directional property than cold wall with directional property. As n increases from 1.5, the trend changes are observed fur refractive index ratio about n=6.10

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 C
• /
• pp.1388-1390
• /
• 1995

The characteristic of dielectric breakdown in solid insulating material dominates the reliability and safety of power equipment and affects directly to its life. In this point of view, the thickness and temperature dependence of dielectric breakdown strength and mechanism of dielectric breakdown in low density polyethylene which has been employed widely as insulating material have been technically reviewed by examinations of thermal property. The dielectric breakdown strength depending on its thickness was measured 2.6[MV/cm] at the thickness of 20[${\mu}m$] and 1.9[MV/cm] at the thickness of 75[${\mu}m$] based on ambient temperature of 30[$^{\circ}C$]. It is shown the temperature dependence that dielectric breakdown strength decreases in linear as the thickness increases. The dielectric breakdown strength depending on temperature was measured 2.6[MV/cm] at the temperature of 30[$^{\circ}C$], 1.6[MV/cm] at 60[$^{\circ}C$] and 1.3[MV/cm] at 90[$^{\circ}C$] based on the thickness of 20[${\mu}m$]. As the ambient temperature increases, the temperature dependence is shown that a very large drop is occurred up to temperature of 60[$^{\circ}C$] and a very small drop is discovered over 60[$^{\circ}C$].