• Title/Summary/Keyword: dielectric polarization

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Influence of the Vulcanization on the Dielectric Proper ties of the Ageing Natural Nubber (노화된 천연고무의 유전특성에 미치는 가황의 영향)

  • Kim, Bong-Heup;Kim, Wang-Kon;Lee, Joon-Ung
    • Elastomers and Composites
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    • v.21 no.3
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    • pp.205-212
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    • 1986
  • The dielectric properties of natural rubber are very important to investigate the molecular structure. The charcteristics of the dielectric absorption in aging natural rubber were studied in the range of frequency from $1{\times}10^3Hz\;to\;3.2{\times}10^7Hz$ at the temperature of $23^{\circ}C$. As the results, it has been confirmed that in the case of aged NR vulcanized specimen with contained sulfur 2 phr above the specimens exhibit two kind of dielectic losses due to the the dipole polarization by impurities and sulfurs, and of raw rubber exhibit the kind of losses due the to dipole polarization. Particularly, it has been affirmed that the dielectric loss spectrum of the aging natural rubber is larger than that the natural rubber, and the dielectric strength of the aging natural rubber drop depreciate respctively.

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Scanning Nonlinear Dielectric Microscopy : Overview -A High Resolution Tool for Observing Ferroelectric Domains and Nano-domain Engineering-

  • Cho, Yasuo
    • Journal of the Korean Ceramic Society
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    • v.40 no.11
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    • pp.1047-1057
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    • 2003
  • A sub-nanometer resolution Scanning Nonlinear Dielectric Microscope (SNDM) was developed for observing ferroelectric polarization. We also demonstrate that the resolution of SNDM is higher than that of a conventional piezo-response imaging. Secondly, we report new SNDM technique detecting higher nonlinear dielectric constants $\varepsilon$$\_$3333/ and $\varepsilon$$\_$33333/. Higher order nonlinear dielectric imaging provides higher lateral and depth resolution. Finally, the formation of artificial small inverted domain is reported to demonstrate that SNDM system is very useful as a nano-domain engineering tool. The nano-size domain dots were successfully formed in LiTaO$_3$ single crystal. This means that we can obtain a very high density ferroelectric data storage with the density above 1T-bits/inch$^2$.

Improvement of Precision in Ferroelectric Polarization Hysteresis Measurement (강유전체 분극 이력곡선의 측정 정밀도 향상)

  • Jae Hwan Park
    • Journal of the Microelectronics and Packaging Society
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    • v.30 no.3
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    • pp.51-55
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    • 2023
  • Measurement of the ferroelectric polarization hysteresis curve is an important means of overall evaluation and interpretation of the ferroelectric structure and dielectric properties. If a resistive component is included in the ferroelectric sample, an error is included in the measured value of the spontaneous polarization. When configuring the electrical circuit to measure the polarization, by properly utilizing the external resistance corresponding to the resistive component included in the sample, the error due to the resistive loss of the sample was excluded and the size of the ferroelectric polarization induced inside could be accurately measured. It is expected that the displacement and dielectric characteristics of ions inside the ferroelectric can be more accurately evaluated through the evaluation of such an accurate polarization hysteresis curve.

Diffraction Anomalies on the Periodic Strip Grating over a Grounded Dielectric Layer in Case of Oblique Incidence and Arbitrary Polarization (임의의 편파로서 비스듬한 각도로 입사하는 전자파의 경우에 대한 접지된 유전체층 위에 놓여있는 주기적인 스트립격자 구조에서의 특이한 회절현상)

  • 조웅희;고지환;조영기
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.2
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    • pp.238-252
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    • 1998
  • Diffraction anomalies in the periodic strip grating over a grounded dielectric layer are investigated for the plane wave incidence case of both arbitrary(oblique) incidence angle and arbitrary polarization by use of the spectral domain method combined with the sampling theorem. Some numerical results for the Bragg and Off-Bragg blazing phenomena for the cases of arbitrary incidence angle and polarization as well as TE and TM polarization are presented along with discussions on those phenomena.

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Origin of Decreasing the Dielectric Constant and the Effect of Ionic Polarization (유전상수가 낮아지는 원인과 이온 분극의 효과)

  • Oh, Teresa
    • Journal of the Korean Vacuum Society
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    • v.18 no.6
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    • pp.453-458
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    • 2009
  • SiOC film was deposited by the chemical vapor deposition using BTMSM and oxygen mixed precursor. The characteristic of SiOC film varied with increasing of the gas flow rate ratios. The dielectric constant was obtained by C-V measurement using the structure of metal/SiOC film/Si. The space effect due to the steric hindrance between alkyl group at terminal bond of Si-$CH_3$ made the pores, and increased the thickness. However, the SiOC film due to the lowering of the polarization decreased the thickness and then decreased the dielectric constant. After annealing process, the dielectric constant decreased because of the evaporation of the OH or $H_2O$ sites. The thickness was related to the lowering of the dielectric constant by the reduction of the polarization and the thickness decreased with the decrease of the dielectric constant. The refractive index was in inverse proportion to thickness. The trends of the thickness and refractive index did not change after annealing.

Comparison to Dielectric Properties of LB Films for Length of Methylene Group (메틸렌기의 길이에 따른 LB막의 유전 특성 비교)

  • Kang, Ki-Ho;Kim, Do-Kyun;Choi, Yong-Sung;Chang, Jeong-Soo;Kwon, Young-Soo
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1843-1845
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    • 1999
  • We have investigated the dielectric characteristics of palmitic acid(PA), stearic acid (SA) and arachidic acid(AA) Langmuir-Blodgett(LB) films because these fatty acid systems have a same hydrophilic group and a different hydrophobic one (alkyl chain length). In this work. fatty acid systems were used as LB films and the status of the deposited films was confirmed by evaluating the transfer ratio. the UV absorption and the capacitance. Also, the dielectric characteristics such as the frequency-capacitance characteristics and the dielectric dispersion and absorption characteristics of PA, SA and AA through-plane were measured. The relative dielectric constants of PA, SA and AA LB films were about $2.6\sim4.6$, $2.4\sim4.1$ and $2.2\sim3.8$, respectively. That is, the relative dielectric constants were decreased in proportion to the chain length of methylene group. And, the dielectric dispersion and absorption of each fatty acid LB films have arisen from spontaneous polarization of dipole polarization in the range of $10^4\sim10^5[Hz]$.

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Effect of Magnetic Field on the Dielectric Properties $BaTiO_3-MgFe_2O_4$ Composite

  • Tadi, Ravindar;Kim, Yong-Il;Kim, Cheol-Gi;Ryu, Kwon-Sang
    • Proceedings of the Korean Magnestics Society Conference
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    • 2011.06a
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    • pp.93-95
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    • 2011
  • In this study we tried to measure the effect of magnetic field on the dielectric properties of $BaTiO_3-MgFe_2O_4$ soft magnetic composite. Composites with different weight percents of ferroelectric and ferromagnetic phases were subjected to magnetic field in the order of 0 to 450 Oe and the variation of the dielectric properties was observed. The Variation of dielectric polarization was discussed in terms of Maxwell-Wagner type polarization in particulate composites.

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Dielectric properties of $Bi_{3.25}La_{0.75}Ti_3O_{12}$ thin films with Bi contents (Bi 첨가량에 따른 BLT 박막의 유전특성)

  • 김경태;김창일;강동희;심일운
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.371-374
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    • 2002
  • Bismuth lanthanum titanate thin films with excess Bi contents were prepared onto Pt/Ti/$SiO_2$/Si substrate by metalorganic decomposition (MOD) technique. The structure and morphology of the films were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. From the XRD analysis, BLT thin films show polycrystalline structure and the layered-perovskite phase was obtained over 10% excess of Bi contents. As a result of ferroelectric characteristics related to the Bi content of the BLT thin film, the remanent polarization and dielectric constant decreased with increasing over Bi content of 10 % excess. The BLT film with Bi content of 10% excess was measured to have a dielectric constant of n9 and dielectric loss of 1.85[%]. The BLT thin films showed little polarization fatigue test up to 3.5 x $10^{9}$ bipolar switching cycling.

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Effect of Antimony Sesquioxide on the Dielectric Property of Rutile $(TiO_2)$ ($TiO_2$ 의 유전성에 미치는 $Sb_2O_3$ 영향)

  • 윤기현;김창수;강영환
    • Journal of the Korean Ceramic Society
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    • v.17 no.2
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    • pp.75-79
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    • 1980
  • The effect of the additive on the dielectric property of $TiO_2$ containing 0-2.5wt %. $Sb_2O_3$ was investigated as a function of frequency from $5{\times}10^4$ to $6.3{\times}10^7$ cps and temperature from 25 to 375$^{\circ}C$. The dielectric constant increased with increasing $Sb_2O_3$ concentration from 0.25 to 0.5wt.% It is due to space charge polarization caused by increasing anion vacanices. The dielectric constant decreased for further increase in $Sb_2O_3$ concentration. It can be explained by increasing grain size effect rather than space charge polarization.

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Some Problems of the Partial Discharge Burning Time

  • Kinsht Nikolay V.;Katz Marat A.
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.6
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    • pp.319-323
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    • 2006
  • The problem of the partial discharge (PD) extinction is investigated. The transient process takes place in a small spherical inclusion which is located in the dielectric. Both the losses caused by polarization and ohmic losses as the dielectric parameters are taken into account. From the inclusion standpoint the dielectric is considered as an active two-pole element (equivalent generator) and inclusion represents by own current-voltage curve. PD extinction voltage was shown to depend on the polarization loss tangent.