• Title, Summary, Keyword: dielectric

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The Simulation of Electric Field Distribution of Dielectric Tube with Two Layers and Gloular Dielectric in Water (수중에서의 이중 절연 방전관과 구형 유전체의 전계 분포 시뮬레이션)

  • Lee, Dong-Hoon;Park, Jae-Youn;Park, Hong-Jae;Koh, Hee-Seog
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.1143-1146
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    • 2003
  • This paper was simulated the electric field distribution in dielectric tube with two layers and spherical dielectric in water. The reactor was made up of the spherical dielectric that is diameter : 2.5[mm], ${\epsilon}_r$ : 5, 25, 100, 1000, 5000 respectively and two glass plate being 2[mm] thickness, ${\epsilon}_r$ : 5 as electrode. The discharge gap was 9[mm]. As a result of the simulation, in case of being about the same value between the dielectric constant of spherical dielectric and water, when the reactor was applied to high voltage, dielectric polarization characteristic was trending toward disappearance. To get more strong electric field, the dielectric constant should be higher comparatively, Increasing the spherical dielectric constant, the location of equippotential line was shifting from the interior to the exterior.

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Dielectric Properties of Complex Cconcentration in IMI-0 Thin Films (IMI-O 초박막의 착체농도에 대한 유전 특성)

  • 정상범;유승엽;박재철;권영수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.345-348
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    • 1999
  • The monolayer behaviors at the air-water interface and the dielectric properties of MI-0 LB films for complex concentration were investigated by the surface pressure-area ($\pi$-A) isotherms and dielectric constant. The molecular area was expanded with increase of metal ions concentration. It is considered that the expansion of molecular area is due to electrostatic repulsion between the polymer chains andhydrophobic increase of ionic strength. In the frequency-dependent complex dielectric constant at room temperature, the real part of dielectric constant($\varepsilon'$) is about 6.0~10.0 in the low-frequency range and is decreasing slowly upto $1O^4$Hz. It decreased abruptly near $1O^5Hz$. It seems to be dielectric dispersion in this frequency range. Also, the imaginary part of dielectric constant ($\varepsilon"$) shows a peak in $1O^5$~$1O^6Hz$. It seems to be dielectric absorption in this frequency range.ange.

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The Effect of Ion Contribution to the Dielectric Properties of $\beta$-PVDF Thin Film Fabricated by Vapor Deposition Method (진공증착법으로 제조된 $\beta$-PVDF 박막의 유전 특성에 미치는 이온의 영향)

  • 박수홍;김종택;이덕출
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.11
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    • pp.1007-1013
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    • 1998
  • In this paper, the dielectric properties of fabricated Polyvinylidene fluoride(PVDF, $PVF_2$) thin film with substrate temperature from 30 to at vapor deposition. The dielectric properties of PVDF thin film had been studied in the frequency range from 10Hz to 4MHz at measuring temperature between 20 and $100^{/circ}C$. The anomalous increasing in dielectric constant and dielectric loss at low frequencies and high temperature was described for PVDF thin film containing ion impurities. In particularly, ion mobility of fabricated PVDF thin film at substrate temperature at $30^{/circ}C$ decrease from $2\times10^{-5}\;to\;3.07$\times10^{-7}cm^2/V.s$ On the other hand, ion density increase abruptly from 1.49\times$$10^{13}$ to $1.5\times$10^{16}$cm^{-3}$ In spite of decreasing of ion mobility, dielectric constants and dielectric loss for PVDF thin film increase rapidly with decreasing frequency and high temperature. It was concluded that the dielectric constants and dielectric loss was related to ion density than to ion mobility at low frequency and high temperatures.

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An Approach to Estimate Dielectric Constant of Low-Loss Materials Using Dielectric Slab Loaded Cylindrical Cavity Resonators (유전체 슬랩이 삽입된 원통형 공진기를 이용한 저손실 물질의 유전 상수 측정)

  • Lee, Won-Hui
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.10
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    • pp.1115-1121
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    • 2008
  • In this paper, dielectric slab loaded cylindrical cavity resonator measurement technique is presented to determine the dielectric constant of a dielectric material. The dielectric constant is measured by the resonant frequency deviation of empty and dielectric slab loaded cavity. Characteristic equations are derived by th exact field analysis. The measurement configurations are formed using HP8719A vector network analyzer and an experimental cylindrical metallic cavity with circular cross-section. The validity of the theory is confirmed by experiments and CST MWS 4.0(3D simulator). The results were in the whole satisfactory. The measured dielectric constant of teflon and bakelite are 2.03 and 4.44, respectively.

Device and Circuit Performance Issues with Deeply Scaled High-K MOS Transistors

  • Rao, V. Ramgopal;Mohapatra, Nihar R.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.4 no.1
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    • pp.52-62
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    • 2004
  • In this paper we look at the effect of Fringe-Enhanced-Barrier-lowering (FEBL) for high-K dielectric MOSFETs and the dependence of FEBL on various technological parameters (spacer dielectrics, overlap length, dielectric stack, S/D junction depth and dielectric thickness). We show that FEBL needs to be contained in order to maintain the performance advantage with scaled high-K dielectric MOSFETs. The degradation in high-K dielectric MOSFETs is also identified as due to the additional coupling between the drain-to-source that occurs through the gate insulator, when the gate dielectric constant is significantly higher than the silicon dielectric constant. The technology parameters required to minimize the coupling through the high-K dielectric are identified. It is also shown that gate dielectric stack with a low-K material as bottom layer (very thin $SiO_2$ or oxy-nitride) will be helpful in minimizing FEBL. The circuit performance issues with high-K MOS transistors are also analyzed in this paper. An optimum range of values for the dielectric constant has been identified from the delay and the energy dissipation point of view. The dependence of the optimum K for different technology generations has been discussed. Circuit models for the parasitic capacitances in high-K transistors, by incorporating the fringing effects, have been presented.

Experimental Investigation on Dielectric and Thermal Characteristics of Nanosized Alumina Filler Added Polyimide Enamel

  • Sugumaran, C. Pugazhendhi
    • Journal of Electrical Engineering and Technology
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    • v.9 no.3
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    • pp.978-983
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    • 2014
  • The polymer nano composite possess good priority recently for engineering applications. Especially the electrical insulating materials attract the high performance of nano composites. In this work the ballmill synthesiation process of nano sized Alumina ($Al_2O_3$), the preparation of new nano composite material with an content of enamel and synthesized Alumina as 1wt%, 3wt% and 5wt%. Experimental investigation has been carried out for the prepared nano composites materials with respect to dielectric parameter measurements such as dielectric loss (tan ${\delta}$), dielectric constant (${\varepsilon}$), dielectric strength under various temperature. The partial discharge level also measured for all the samples and the PD inception voltage is also observed and compared. Weight loss of the material has been analyzed through TGA. It has been experimentally proved that 3wt% of Alumina nano filler added enamel has significant improvement in the dielectric and thermal properties.

A Study on the Changes in Dielectric Constant of Engine Oil (엔진오일의 유전상수 변화에 관한 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.2
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    • pp.99-104
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    • 2006
  • The dielectric constants of fresh engine oils were obtained according to various types of oil, temperatures and frequencies. Through analyzing the characteristics of dielectric constant, the related correlation between the changes in dielectric constant of oil and the degree of oil deterioration is going to be found. The dielectric constant was calculated by cross capacitances measured by a sensor tube. Before finding the correlation, as a prerequisites study, the best condition measuring the dielectric constant was found. In general, it was found that the value of dielectric constant became stable below $60^{\circ}C$ regardless frequency variation. Further, above 6kHz, the dielectric constant became stable even if temperature had been above $100^{\circ}C$.

Effect of the Front Dielectric Layer on the Efficacy of the Plasma Display Panel

  • Moon, Won-Seok;Oh, Jin-Mok;Seo, Byung-Hwa;Lee, Sung-Wook;Byun, Na-Mi;Cho, Yun-Hui;Ryu, Byung-Gil;Kim, Sung-Tae
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.31-34
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    • 2009
  • We investigated the effect of relative dielectric constant of front dielectric layer on the efficacy of plasma display panel. Dielectric materials with relative dielectric constant of around 6 and 7 were developed. When the front dielectric layer had a low relative dielectric constant, power consumption decreased more than luminance did. And it led to efficacy enhancement. However, the minimum sustain voltage increased.

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Highly flexible dielectric composite based on passivated single-wall carbon nanotubes (SWNTs)

  • Jeong, Hyeon-Taek;Kim, Yong-Ryeol
    • Journal of the Korean Applied Science and Technology
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    • v.32 no.1
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    • pp.40-47
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    • 2015
  • Single-walled carbon nanotubes (SWNTs) was modified with various length of linear alkyl chains and passivated to form dielectric filler. The modified SWNTs embedded into epoxy matrix to fabricate a flexible composite with high dielectric constant. The dielectric behavior of the composite was significantly changed with various alkyl chain length(n) of pyrene. The dielectric constant of the epoxy/SWNTs composite significantly increased with respect to increase in length of alkyl chain at the frequency range from 10 to 105Hz (n=12and18).We also found that the passivated epoxy/SWNTs composite with high dielectric constant presented low dielectric loss. The resulted dielectric performances corresponded to de-bundling of nanotubes and their distribution behavior in the matrix in terms of tail length of alkyl pyrene in the passivation layer.

Dielectric Properties of Epoxy/Micro-sized Alumina Composite and of Epoxy/Micro-sized/Nano-sized Alumina Composite

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.6
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    • pp.338-341
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    • 2015
  • Epoxy/micro-sized alumina composite was prepared, and the effects of alumina content on the dielectric properties were investigated in order to develop an insulation material for gas-insulated switchgears (GIS). Nano-sized alumina (average particle size: 30 nm) was also incorporated into the epoxy/micro-sized alumina composite. Dielectric tests were carried out in ASTM D 150, and capacitance (Cp) and dielectric loss (tanδ) were measured. The dielectric constant increased with increasing alumina content in the epoxy/micro-alumina system and the epoxy/micro-alumina/nano-alumina system. As 1,3-diglycidyl glyceryl ether (DGE) content increased, the dielectric constant decreased and dielectric loss increased. This ocurred as a result of the weak electric field enhancement due to homogeneous dispersion of micro- and nano-sized alumina particles in an epoxy composite.