• 제목/요약/키워드: material constant

검색결과 2,912건 처리시간 0.025초

액체유도체의 절연특성에 미치는 초음파의 영향 (Ultransonic Effect on the Break-Down Characteristics of Liquid Dielectrics)

  • 전춘생;김홍근;홍봉식
    • 전기의세계
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    • 제26권4호
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    • pp.61-67
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    • 1977
  • This paper treats the Ultrasonic effects on the break down characteristics of Liquid Dielectric Material 1) Relative Dielectric constant, Es of Liquid Dielectric Material at a constant temperature decreases in proportion to the irradiated time of Ultrasonic radiation and its intensity, and reaches to a certain saturated value. The saturated value varies with the intensity of Ultrasonic radiation. 2) Power factor of Liquid Dielectric Material at a constant temperature increases in proportion tothe irradiated time of Ultrasonic radiation and its intensity, and reaches to a certain saturated value. The saturated value varies with the intensity of Ultrasonic radiation. 3) Relative resistance of Liquid Dielectric Material at a constant temperature decrease with the irradiated time of Ultrasonic radiation, but the effect of its intensity is very irregular. 4) Break-down strength of Liquid Dielectric Material, at a constant temperature decreases with the irradiated time of Ultrasonic radiation and its intensity, and then reaches to a saturated value.

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Calculation of Field Enhancement Factor in CNT-Cathodes Dependence on Dielectric Constant of Bonding Materials

  • Kim, Tae-Sik;Shin, Heo-Young;Cho, Young-Rae
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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    • pp.1092-1095
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    • 2005
  • The effect of the dielectric constant (${\varepsilon}$) of bonding materials in screen-printed carbon nanotube cathode on field enhancement factor was investigated using the ANSYS software for high-efficient CNT-cathodes. The field enhancement factor increased with decreasing the dielectric constant and reaching a maximum value when the dielectric constant is 1, the value for a vacuum. This indicates that the best bonding materials for screen-printing CNT cathodes should have a low dielectric constant and this can be used as criteria for selecting bonding materials for use in CNT pastes for high-efficient CNT-cathodes

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질화규소 세라믹스의 고온(~1,000 ℃) 유전상수 변화와 산화 거동의 상관관계 고찰 (Correlation between Dielectric Constant Change and Oxidation Behavior of Silicon Nitride Ceramics at Elevating Temperature up to 1,000 ℃)

  • 용석민;고석영;정욱기;신다혜;박진우;최재호
    • 한국군사과학기술학회지
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    • 제25권6호
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    • pp.580-585
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    • 2022
  • In this study, the high-temperature dielectric constant of Si3N4 ceramics, a representative non-oxide-based radome material, was evaluated and the cause of the dielectric constant change was analyzed in relation to the oxidation behavior. The dielectric constant of Si3N4 ceramics was 7.79 at room temperature, and it linearly increased as the temperature increased, showing 8.42 at 1,000 ℃. As results of analyzing the microstructure and phase for the Si3N4 ceramics before and after heat-treatment, it was confirmed that oxidation did not occur at all or occurred only on the surface at a very insignificant level below 1,000 ℃. Based on this, it is concluded that the increase in the dielectric constant according to the temperature increase of Si3N4 ceramics is irrelevant to the oxidation behavior and is only due to the activation of charge polarization.

Can be the dielectric constant of thin films as-grown at room temperature higher than that of its bulk material?

  • Jung, Hyun-June;Kim, Chung-Soo;Lee, Jeong-Yong;Yoon, Soon-Gil
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.23-23
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    • 2010
  • The $Bi_2Mg_{2/3}Nb_{4/3}O_7$ (BMNO)-Bi composite films sandwiched by an $Al_2O_3$ protection layer exhibited a linear increase of a dielectric constant with increasing thickness and the 1000nm-thick BMNO-Bi composite films showed a dielectric constant (~220) higher than that of its bulk material (~210), keeping a low leakage current density of about $0.1{\mu}A/cm^2$. An enhancement of the dielectric constant in the BMNO-Bi composite films was attributed to the hybrid model combined by a space charge polarization, dipolar response, and nano-capacitors. On the other hand, 1000nm-thick BMNO-Bi composite films sandwiched by 40nm-thick BMNO layer exhibited a dielectric constant of about 450 at 100 kHz and a leakage current density of $0.1{\mu}A/cm^2$ at 6V.

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비가공 물질의 유전 상수 측정 방법 (A Dielectric Constant Measurement Method of Unprepared Samples)

  • 이원희
    • 한국전기전자재료학회논문지
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    • 제21권10호
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    • pp.896-900
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    • 2008
  • A measurement method of the dielectric constant of materials whose standard sample is not prepared easily is proposed. The unprepared sample of the material is placed in a cavity, and the resonant frequency is measured. A commercial software simulates the same sample and the cavity leading to find the correct dielectric constant. The measured samples include a ceramic, a forced glass, and a powdered enamel. The measured dielectric constant of a ceramic, a forced glass, and a powdered enamel are 11-j0.0033(${\epsilon}_{\gamma}=11,\;tan{\delta}=0.0003$), 4.15-j0.053(${\epsilon}_{\gamma}=4.15,\;tan{\delta}=0.0128$), and 3.9-j0.042(${\epsilon}_{\gamma}=3.9,\;tan{\delta}=0.0108$) respectively.

등방성체와 직교이방성체의 접합계면네 내재된 동적모드 III 균열의 등속전파 (Dynamic Mode III Crack Propagated with Constant Velocity at Interface Between Isotropic and Orthotropic Material)

  • 이광호;황재석;유재용
    • 대한기계학회논문집A
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    • 제20권12호
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    • pp.3828-3837
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    • 1996
  • The dynamic problems of interface crack propagated with constant velocity along the interface of bimateraial composed of isotropic and orthotropicmaterial under antiplane loading condition are studied in this paper. The general dynamic stress fields and displacement fields of mode III are derived when interface crack between isotropic and orthotropic material is propagating with constant velocity. The general dynamic stress fields and displacement fields in isotropic material. Finally, the characteristics of interface crack propagation are studied with various properties of isotropic and orthotropic material and crack propagarion velocities.

열처리온도에 따른 SBN 세라믹 박막의 특성

  • 김진사;송민종;박건호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.90-90
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    • 2009
  • The $Sr_{0.7}Bi_{2.3}Nb_2O_9$(SBN) thin films are deposited on Pt-coated electrode($Pt/Ti.SiO_2/Si$) using RF sputtering method. The dielectric constant of SBN thin films were increased with the increase of annealing temperature. The maximum dielectric constant of SBN thin film is obtained by annealing at 700[$^{\circ}C$]. The dielectric constant and dielectric loss had a stable value within -5~+5[V].

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집중 등가회로를 사용한 압전 변압기의 승합비 및 효율 해석 (Voltage Gain and Efficiency Analysis of Piezoelectric Transformer using Lumped constant Equivalent Circuit)

  • 류주현;이용우;윤광희;정희승;정영호;박창엽
    • 한국전기전자재료학회논문지
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    • 제11권10호
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    • pp.849-854
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    • 1998
  • The load characteristics on the voltage gain and efficiency were analyzed using a lumped constant equivalent circuit of the piezoelectric transformer. These analytical results were confirmed by experiments. Theoretical values of voltage gain were nearly constant with experimental ones. However, It was shown that theoretical values of efficiency is higher than experimental ones.

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Rosen형 압전 트랜스포머의 집중등가회로를 사용한 승압비 및 효율 해석 (Voltage Gain and Efficiency Ana1ysis of Piezoelectric Transformer using Lumped Constant Equivalent Circuit)

  • 김만성;류주현;정회승;박창엽;정영호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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    • pp.183-189
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    • 1998
  • In this paper, The load characteristics on the voltage gain and efficiency were analyzed sing an lumped constant equivalent circuit of the piezoelectric transformer. These analytical results are confirmed by experiments. Theoretical values of voltage gain were nearly constant with experimental ones. However, It was shown that theoretical values of efficiency had higher values than experimental ones.

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