1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319)最新文献_第8页

Polarization profiles in fatigued ferroelectric polymers 疲劳铁电聚合物的极化谱

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804592

A. Limbong, Z. Zheng, I. Guy, D. Das-Gupta

{"title":"Polarization profiles in fatigued ferroelectric polymers","authors":"A. Limbong, Z. Zheng, I. Guy, D. Das-Gupta","doi":"10.1109/CEIDP.1999.804592","DOIUrl":"https://doi.org/10.1109/CEIDP.1999.804592","url":null,"abstract":"When ferroelectric materials are subjected to repeated reversal of polarisation, the magnitude of the reversed polarisation is observed to decrease. This phenomenon is referred to as fatigue and is generally ascribed either to space charge effects or to the pinning of domain walls at defects. In recent times several techniques have been developed which allow the study of polarization profiles in thin, insulating films. In the present work, the polarization profiles in fatigued ferroelectric polymers were measured using the laser intensity modulation method (LIMM). The polymers studied were polyvinylidene fluoride (PVDF) and its copolymers with trifluoroethylene (TrFE). The polymers were fatigued by reversing the polarisation many times using a cyclic field with an amplitude above the coercive field. For some of the polymers, this leads to a decrease in the magnitude of the reversed polarization, while for others, the magnitude remained reasonably constant. It was found that those polymers which showed most fatigue in their hysteresis loops had a more symmetrical distribution of polarization after fatiguing. The lack of fatigue and asymmetrical polarization profiles seem to be associated with materials which contain the non-polar /spl alpha/ crystal form.","PeriodicalId":267509,"journal":{"name":"1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131510334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Flow electrification induced electrohydrodynamic secondary flow 流动通电引起电流体动力二次流

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.807925

J. Chang, G. Touchard

{"title":"Flow electrification induced electrohydrodynamic secondary flow","authors":"J. Chang, G. Touchard","doi":"10.1109/CEIDP.1999.807925","DOIUrl":"https://doi.org/10.1109/CEIDP.1999.807925","url":null,"abstract":"Theoretical and numerical investigations have been conducted to evaluate the on-set conditions of flow electrification induced electrohydrodynamic secondary flow in smooth pipe and pipe with multiple cylinders in cross flow conditions. The nondimensional parameters control flow electrification and electrohydrodynamic (EHD) flow were derived from the mass conservation, momentum conservation, energy conservation, charged particle transport and Poisson's equations for liquid flow. For single-phase flow of liquid, in addition to conventional dimensionless numbers for flow heat and mass transfers (Re, Ra, Pr, Sc), and EHD flow (E/sub t0/, E/sub t/spl epsi//), new variables the Debye number D/sub b/, ion drift number F/sub E/ are defined. The results show that the EHD number based on the space charge density /spl Gt/ Re/sup 2/ is required for the inducing EHD secondary flow in the downstream of pipe for single phase flow. The results also show that the change in relaxation time should be used only when F/sub E//spl Gt/1 and F/sub E//spl Gt/ReSc/sub i/ conditions. We propose that the Debye number D/sub b/, Re and Sc/sub i/ replace the change relaxation time for the transient change relaxation estimation in fluid flow. The effect of flow on the electrification is also expressed in terms of diffusion Reynolds number of ions.","PeriodicalId":267509,"journal":{"name":"1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128205761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

On the measurement of the volume conductivity of insulators 关于绝缘体体积电导率的测量

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804621

R. Coelho

引用次数: 0

Calculated particle trajectories in GIS of different designs and the verification by optical and acoustic measurements 计算不同设计的GIS中的粒子轨迹，并通过光学和声学测量进行验证

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804666

M. Knapp, K. Feser, V. Rees

引用次数: 0

Insulation performance of 10% SF/sub 6//90% N/sub 2/ mixture 保温性能为10% SF/sub 6//90% N/sub 2/混合物

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804671

M. Piemontesi, F. Koenig, L. Niemeyer, C. Heitz

引用次数: 13

Permittivity of composite composites 复合材料的介电常数

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804596

C. Brosseau, A. Beroual, A. Boudida

引用次数: 1

Studies on the dielectric strength of oil-polymer composite insulation under variable frequency AC voltages 变频交流电压下油-聚合物复合绝缘材料介电强度的研究

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804651

M. Nagao, S. Jayaram, M. Sugio, E. P. Waldi

引用次数: 8

Streamer propagation in oxygen between spherical electrodes: a numerical simulation with a particle method 球形电极间氧中的流光传播:粒子法的数值模拟

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804681

C. Soria, F. Pontiga, A. Castellanos

引用次数: 0

Application of dielectric response measurements for condition assessment of service aged XLPE cables 介电响应测量在服役老化交联聚乙烯电缆状态评估中的应用

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.804607

E. Ildstad, H. Faremo

引用次数: 4

Modelling and characterisation of electrical trees in a laminated dielectric structure 层压电介质结构中电树的建模和表征

1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319) Pub Date : 1999-10-17 DOI: 10.1109/CEIDP.1999.807882

Ramanujam Sarathi, A. V. Saradhi

引用次数: 1