• Title/Summary/Keyword: dielectric-rod

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Application of Dielectric-loaded Cavity Resonators with HTS Endplates for Tunable High-Q Resonators and Characterization Tools for Large HTS Films (고온초전도 박막이 설치된 유전체부하 공진기의 주파수 조절 가능한 High-Q 공진기 제작 및 대면적 고온초전도 박막의 특성평가에의 응용)

  • Kwon, Hyeong-Jun;Park, Jong-Un;Kang, Hun;Hur, Jung;Lee, Sang-Young
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.75-82
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    • 1999
  • TE$_{01\;{\delta}}$ mode Cavity Resonators with a low loss dielectric rod and YBa$_2Cu_3O_{7-{\delta}}$ (YBCO) endplates were prepared and their microwave properties were studied at temperatures above 30 K. Both sapphire and rutile were used as the dielectrics. The TE$_{01\;{\delta}}$ mode Q$_0$ of the resonator, designed to work as a tunable resonator with variations in the gap distance (s) between the dielectric rod and the top YBCO, was more than 1000000 at s = 0 mm and at 30 K and .the resonant frequency of 19.56GHz when a sapphire rod was used for the dielectric. The TE$_2Cu_3O_{7-{\delta}}$ mode resonant frequency (f$_0$) appeared to decrease as the temperature is raised. Meanwhile, the temperature dependence of the TE$_2Cu_3O_{7-{\delta}}$ mode f$_0$ of the rutile-loaded resonator appeared different with f$_0$ increasing according to the temperature and Q$_0$ more than 300000 at 30 K and f$_0$ = 8.56 CHz. Comparisons were made between the microwave properties of the sapphire-loaded and the rutile-loaded resonators. Also, applications of the TE$_2Cu_3O_{7-{\delta}}$ mode cavity resonator for a tunable resonator with a very high Q$_0$ as · well as a characterization tool for surface resistance measurements of HTS films are described.

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Electrohydrodynamic Flow around a Circular-Cylindrical Rod Submerged in a Dielectric Liquid (비전도성 액체에서의 실린더 막대 주변에 생기는 전기동역학적 유체흐름)

  • Park, Hyun-Jin;Ryu, Jae-Chun;Kang, Kwan-Hyoung
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.51-54
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    • 2007
  • The induced-charge electroosmosis (ICEO) is a kind of electroosmotic flow which is generated by the electrical charge induced by an externally-applied electric field. That kind of electrokinetic phenomenon provides a nonmechanical technique to handle microscale flows and particles. In this work, we report that the ICEO-like flow is observed around two kinds of circular-cylindrical rod submerged in a dielectric liquid. The conductivity of the solution is varied by adding a surfactant. The flow field is visualized by the PIV method, and average flow speed shows a remarkable dependence on electrical input frequency. Interestingly, the characteristics of the flow are quite different from the conventional ICEO with respect to the flow direction and the locations of center of vortices.

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Accurate Measurements of the Unloaded Q of a Dielectric-loaded High-Q $TE_{01{\delta}}$ mode Cavity Resonator with HTS Endplates

  • Kwon, H.J.;Hur, Jung;Lee, Sang-Young
    • Progress in Superconductivity
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    • v.1 no.1
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    • pp.36-41
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    • 1999
  • Methods for mode identification and accurate measurements of the unloaded Q ($Q_0$) of a dielectric-loaded $TE_{01{\delta}}$ mode cavity resonator with HTS endplates are proposed. A resonator with a sapphire rod and $YBa_2Cu_3O_{7-x}$(YBCO) endplates was prepared and its microwave properties were studied at temperatures above 30 K. The $TE_{01{\delta}}$ mode $Q_0$ of the resonator, designed to work as a tunable resonator with variations in the gap distance (s) between the sapphire rod and the top YBCO, was more than 1000000 at s = 0 mm and at 30 K with the resonant frequency of 19.56 GHz. The $TE_{01{\delta}}$ mode $Q_0$ decreases as s increases for s < 2 mm until mode couplings between the $TE_{01{\delta}}$ mode and other modes appeared at s = 2 mm. Significant dependence of the $TE_{01{\delta}}$ mode $Q_0$ on the input and output coupling constants was also observed. Applications of the open-ended $TE_{01{\delta}}$ mode cavity resonator for a tunable resonator with a very high Q as well as a characterization tool for the surface resistance measurements of HTS films are described.

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The Exact Field Representation in Cylindrical Cavity Resonators with Concentric Dielectric-rod (동심 유전체 봉이 삽입된 원통형 공진기의 정확한 전자계 표현)

  • Choi, Hong-Ju;Lee, Won-Hui;Hur, Jung;Choi, Gwang-Je;Lee, Sang-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.8
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    • pp.1399-1406
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    • 2000
  • The exact electromagnetic field in cylindrical cavity with concentric dielectric rod is analyzed. Resonant frequency of dielectric loaded cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. As the result of comparing calculation value and experimental value of resonant frequencies, we know that the field representation of traveling mode is exact.

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Dielectric Relaxation Phenomena of DMPC LB Thin Film (DMPC LB박막의 유전완화현상)

  • Choi, Youbg-Il;Song, Jin-Won;Cho, Su-Young;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.822-825
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    • 2003
  • Maxwell displacement current (MDC) measurement has been employed to study the dielectric property of Langmuir-films. A method for determining the dielectric relaxation time $\tau$ of floating monolayers on water surface is presented. WC flowing across monolayers is analyzed using a rod-like molecular model. It is revealed that the dielectric relaxation time $\tau$ of monolayers in the isotropic polar orientational phase is determined using a liner relationship between the monolayer compression speed ${\alpha}$ and the molecular area Am. Compression speed ${\alpha}$ was about 30, 40, 50mm/min.

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Dielectric Relaxation Characteristics of Phospholipid Membrane (인지질막의 유전완화 특성)

  • 이경섭;조수영;박석순;정헌상;최영일
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.173-176
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    • 1998
  • We experimentally investigated the dielectric relaxation phenomena of a liquid crystal monolayers by the Displacement current techique and displacement current flowing across monolayers is analyzed using rod-like molecular model. It is revealed that the dielectric reaxation time $\tau$ of monolaters in the isotropic polar orientational phase is determined using a linear relashionship between the monolayers compression speed $\alpha$ and the molecular area. The dielectric relaxation time of phospholipid monolayers was examined on the basis of the analysis developed here.

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Dielectric Relaxation Time of Long Chain Fatty Acid Langmuir films (장쇄지방산 L막의 완화 시간)

  • Cho, Dong-Kyu;Chang, Hun;Oh, Jae-Han;Gang, Yong-Chul;Choi, Young-Il;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.279-282
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    • 2000
  • The displacement current measurement has been employed to study the dielectric properties of Langmuir films. A method for determining the dielectric relaxation time $\tau$ of floating monolayers on water surface is presented. The displacement current flowing across monolayers is analyzed using a rod-like molecular model. It's revealed that the dielectric relaxation time $\tau$ of monolayers in the isotropic polar orientational phase is determined using a liner relationship between the monolayers compression speed $\alpha$ and the molecular maximum area $A_{m}$. The compression speed $\alpha$ was about 30, 40, 50mm/minmm/min

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Dielectric Relaxation Characteristics of Biology Thin Film (생체박막의 유전완화특성)

  • Song, Jin-Won;Cho, Su-Young;Lee, Kyung-Sup;Sin, Hun-Gyu
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05c
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    • pp.107-110
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    • 2003
  • In this paper, We introduced that the method for determing the dielectric relaxation time $\tau$ of floating monolayers on water interface. Displacement current flowing across monolayers is analyzed using a rod-like molecular model. It is revealed that the dielectric relaxation time $\tau$of monolayers in the isotropic polar orientational phase is determined using a linear relationship between the monolayer compression speed $\alpha$ and the molecular area Am. here Displacement current gives a peak at A = Am. The dielectric relaxation time $\tau$ of organic monolayers was examined on the basis of the analysis developed here.

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A study on the Dielectric Relaxation Phenomena of phospolipid monolayers Film (인지질 단분자막의 유전완화현상에 관한 연구)

  • Cho, Su-Young;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.431-434
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    • 2003
  • In this paper, We introduced that the method for deforming the dielectric relaxation time $\tau$ of floating monolayers on water interface. Displacement current flowing across monolayer is analyzed using a rod-like molecular model. It is revealed that the dielectric relaxation time $\tau$ of monolayers in the isotropic polar orientational phase is determined using a linear relashionship between the monolayer compression speed a and the molecular area $A_m$. A displacement current gives a peak at A=$A_m$. The dielectric relaxation time $\tau$ of phospolipid monolayers was examined on the basis of the analysis developed here.

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