• Title/Summary/Keyword: charge distribution

Search Result 707, Processing Time 0.069 seconds

Analysis of Insulating Reliability in Epoxy Composites using Weibull Distribution Equation (와이블 분포식을 이용한 에폭시 복합체의 절연 신뢰도 분석)

  • Park, No-Bong;Lim, Jung-Kwan;Park, Yong-Pil
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2003.05a
    • /
    • pp.813-816
    • /
    • 2003
  • The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were applied to Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased, the stronger breakdown strength became at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric field is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher. Finally, according to Weibull distribution analysis, reducing breakdown probability of equipment insulation lower than 0.1 % level requires the allowable field intensity values to be kept under 21.5 MV/cm.

  • PDF

Temperature Dependence of Conductivities of Recyclable Polyethylene and Polypropylene and its Effects on Electric Field Distribution in Power Cable (재활용 가능한 폴리에틸렌과 폴리프로필렌의 전도도 온도의존성과 전력케이블 내의 전계분포에 미치는 영향)

  • Lee, June-Ho;Kong, Tae-Sik;Kim, Seong-Jung;Kwon, Ki-Hyung;Cho, Kyu-Cheol;Hozumi, Naohiro
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.60 no.10
    • /
    • pp.1881-1887
    • /
    • 2011
  • In this work the recyclable new polyethylene(PE) and polypropylene(PP), which are thermoplastic, have been investigated as the eco-friendly insulating candidates to replace the cross-linked polyethylene (XLPE). The temperature dependence of conductivities of these materials has been measured and its effects on electric field and space charge distribution in polymeric insulated power cable under temperature gradient have been calculated. It is shown that the sensitivity of conductivity to temperature change has more critical influence to determine the electric field distribution in the power cable than the absolute value of conductivity does and it can be said that the temperature dependence is one of most important factors for the power cable design.

Analysis of Insulating Reliability in Epoxy Composites Using Weibull Distribution Equation (와이블 분포식을 이용한 Epoxy 복합체의 절연 신뢰도 해석)

  • 임중관;박용필;이준웅
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.14 no.8
    • /
    • pp.647-651
    • /
    • 2001
  • The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were applied to Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased, the stronger breakdown strength became at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric filed is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher. Finally, from the analysis of weibull distribution, it was confirmed that to low allowed breakdown probability under 0,.1%, the applied field value needed to be under 21.5MV/cm.

  • PDF

Effects of Turbulence Diffusion and Secondary Flows on the Particle Concentration Distribution in Single Stage ESP (1단 전기집진기에서 난류확산과 2차유동이 입자의 농도분포에 미치는 영향)

  • 정상현;김상수;김용진
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.19 no.9
    • /
    • pp.2271-2282
    • /
    • 1995
  • Numerical simulations for the effects of secondary flow and turbulence diffusion on the particle concentration distributions have been carried out for the single stage electrostatic precipitator. The electrohydrodynamic secondary flow, particle concentration distribution and collection efficiency have been evaluated as a function of dimensionless parameters such as Re, Nend, Pe x. The results of simulations show that for increasing secondary flow intensity the concentration distribution is drastically deformed and collection efficiency is decreased which is more than due to turbulent diffusion.n.n.

FUZZY TORQUE CONTROL STRATEGY FOR PARALLEL HYBRID ELECTRIC VEHICLES

  • PU J.-H.;YIN C.-L.;ZHANG J.-W.
    • International Journal of Automotive Technology
    • /
    • v.6 no.5
    • /
    • pp.529-536
    • /
    • 2005
  • This paper presents a novel design of a fuzzy control strategy (FCS) based on torque distribution for parallel hybrid electric vehicles (HEVs). An empirical load-regulating vehicle operation strategy is developed on the basis of analysis of the components efficiency map data and the overall energy conversion efficiency. The aim of the strategy is to optimize the fuel economy and balance the battery state-of-charge (SOC), while satisfying the vehicle performance and drivability requirements. In order to accomplish this strategy, a fuzzy inference engine with a rule-base extracted from the empirical strategy is designed, which works as the kernel of a fuzzy torque distribution controller to determine the optimal distribution of the driver torque request between the engine and the motor. Simulation results reveal that compared with the conventional strategy which uses precise threshold parameters the proposed FCS improves fuel economy as well as maintains better battery SOC within its operation range.

A Study on the Effects of Relationship Characteristics to Repurchase Intention in the Distribution Channels of Travel Agency (여행도매업체와 여행소매업체간 관계형성 영향요인에 관한 연구)

  • Shim, Jong-Seop;Lee, Nark-Kwee
    • Korean Business Review
    • /
    • v.15
    • /
    • pp.25-45
    • /
    • 2002
  • The purpose of study is to examine how tour wholesaler's relationship characteristics to tour retailer affect trust, commitment, and repurchase intention in the distribution channel of travel industry. There are several detailed purposes of this study. First, this study is to grasp the factors of tour wholesaler's relationship characteristics to tour retailer. Secondly, this study is to examine how tour wholesaler's relationship characteristics to tour retailer affect trust and commitment. Thirdly, this study is to examine how trust on tour wholesaler, which is divided into two levels, firm and salesperson in charge, affects each other and commitment. Fourthly, this study is to examine how trust on tour wholesaler finn and salesperson in charge and commitment affect repurchase intention. Fifthly, this study is to suggest more efficient basis for marketing strategies to C.E.O or officer in charge of decision making of tour wholesaler, and help them to make right decisions. Managerial implications can be drawn from this study. One is that it is recognized that tour wholesaler's relationship characteristics to tour retailer consist of those to tour wholesaler finn such as reputation, physical characteristics, communication and those to salesperson in charge such as expertise, likability, similarity, frequent contact affect trust and commitment positively. Therefore, C.E.O and officer in charge of decision making of tour wholesaler should set up marketing strategies to get positive results at both levels, a finn and a salesperson. The other is that it is important that a tour wholesaler should manage their tour retailer with relationship oriented methods such as building trust, and make every endeavor to retain long term relationship with tour retailer.

  • PDF

Electrical characteristics of Au/3C-SiC/Si/Al Schottky, diode (Au/3C-SiC/Al 쇼터키 다이오드의 전기적 특성)

  • Shim, Jae-Cheol;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2009.11a
    • /
    • pp.65-65
    • /
    • 2009
  • High temperature silicon carbide Schottky diode was fabricated with Au deposited on poly 3C-SiC thin film grown on p-type Si(100) using atmospheric pressure chemical vapor deposition. The charge transport mechanism of the diode was studied in the temperature range of 300 K to 550 K. The forward and reverse bias currents of the diode increase strongly with temperature and diode shows a non-ideal behavior due to the series resistance and the interface states associated with 3C-SiC. The charge transport mechanism is a temperature activated process, in which, the electrons passes over of the low barriers and in turn, diode has a large ideality factor. The charge transport mechanism of the diode was analyzed by a Gaussian distribution of the Schottky barrier heights due to the Schottky barrier inhomogeneities at the metal-semiconductor interface and the mean barrier height and zero-bias standard deviation values for the diode was found to be 1.82 eV and s0=0.233 V, respectively. The interface state density of the diode was determined using conductance-frequency and it was of order of 9.18×1010eV1cm2.

  • PDF

Decay Process of Charge Distribution in E-beam Irradiated Polymers (전자빔 조사 폴리머의 전자 분포의 축퇴 과정)

  • Choi, Yong-Sung;Kim, Hyung-Gon;Hwang, Jong-Sun;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2008.04c
    • /
    • pp.69-72
    • /
    • 2008
  • Decay processes of accumulated charge in e-beam irradiated polymers during elevating temperature are observed using pulsed electro-acoustic measurement system. Since the polymeric materials have many superior properties such as light-weight, good mechanical strength, high flexibility and low cost, they are inevitable materials for spacecrafts. In space environment, however, the polymers sometimes have serious damage by irradiation of high energy charged particles. When the polymers of the spacecraft are irradiated by high energy charged particles, some of injected charges accumulate and remain for long time in the bulk of the polymers. Since the bulk charges sometimes cause the degradation or breakdown of the materials, the investigation of the charging and the decay processes in polymeric materials under change of temperature is important to decide an adequate material for the spacecrafts. By measuring the charge behavior in e-beam irradiated polymer, such as polyimide or polystyrene, it is found that the various accumulation and decay patterns are observed in each material. The results seem to be useful and be helpful to progress in the reliability of the polymers for the spacecraft.

  • PDF

Simulation of channel dimension dependent conduction and charge distribution characteristics of silicon nanowire transistors using a quantum model (양자모델을 적용한 실리콘 나노선 트랜지스터의 채널 크기에 따른 전도 및 전하분포 특성 시뮬레이션)

  • Hwang, Min-Young;Choi, Chang-Yong;Koo, Sang-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2009.04b
    • /
    • pp.77-78
    • /
    • 2009
  • We report numerical simulations to investigate of the dependence of the on/off current ratio and channel charge distributions in silicon nanowire (SiNW) field-effect transistors (FETs) on the channel width and thicknesses. In order to investigate the transport behavior in devices with different channel geometries, we have performed detailed two-dimensional simulations of SiNWFETs and control FETs with a fixed channel length L of 10um, but varying the channel width W from 5nm to 5um, and thickness t from 10nm to 30nm. We have shown that QON/QOFF drastically decreases (from 2.9×104 to 9.8×103) as the channel thickness increases (from 10nm to 30nm). As a result of the simulation using a quantum model, even higher charge density in the bottom of SiNW channel was observed than that in the bottom of control channel.

  • PDF

Influence of Illumination on Domain Switching and Photovoltaic Current in Poled (Pb1xLax)TiO3 Freeoelectric Ceramics

  • Park, Si-Kyung;Park, Dong-Gu;Kim, Sung-Ryul
    • The Korean Journal of Ceramics
    • /
    • v.6 no.3
    • /
    • pp.267-271
    • /
    • 2000
  • The influence of photoexcited nonequilibrium carriers on domain switching and photovoltaic current was investigated in two kinds of poled La-modified PbTiO3ferroelectric ceramics, (Pb0.85La0.15)TiO3and (Pb0.76La0.24)TiO3, under illumination in the absence of external electric field. Both photovoltaic current and cumulative AE event counts increased with illumination time. The observed nonsteady-state photovoltaic current could be explained on the basis of the cycles of a series of physical events consisting the establishment of space charge field by photoexcited carriers trapped at the grain boundaries, the photoinduced domain switching, and the increase in the remanent polarization. An analysis of energy distribution of the observed AE signals also revealed that the space charge field in (Pb0.85La0.15)TiO3allowed both 180C and 90domains to be switched during illumination.

  • PDF