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Proceedings. 11th International Symposium on Electrets最新文献

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Time dependence of dielectric properties of tissue-equivalent dielectric liquid materials 组织等效介电液体材料介电特性的时间依赖性
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042951
K. Fukunaga, S. Watanabe, Y. Yamanaka
{"title":"Time dependence of dielectric properties of tissue-equivalent dielectric liquid materials","authors":"K. Fukunaga, S. Watanabe, Y. Yamanaka","doi":"10.1109/ISE.2002.1042951","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042951","url":null,"abstract":"Standard measurement methods of the specific absorption rate including recipes of tissue-equivalent dielectric liquids have been discussed by international organisations in order to evaluate mobile telecommunication equipment. Specific absorption rate is generally determined by measuring the electric field distribution in a phantom made of a shell filled with tissue-equivalent dielectric liquid. Based on the dielectric properties of various tissues, recipes of the liquids are proposed in international standards. We measured the time dependence of permittivities and conductivities of tissue-equivalent dielectric liquids made of deionised water and polyhydric alcohol, and discussed its influence on specific absorption rate values. The results suggest that permittivities decreased with time due to evaporation of water. The specific absorption rate, however, was not affected significantly by the change of permittivity.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123099623","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
Conductivity induced polarization in two-phase ferroelectric materials 两相铁电材料的电导率诱导极化
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042981
H. von Seggern, S. Fedosov
{"title":"Conductivity induced polarization in two-phase ferroelectric materials","authors":"H. von Seggern, S. Fedosov","doi":"10.1109/ISE.2002.1042981","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042981","url":null,"abstract":"It is commonly believed that formation of polarization and its switching in ferroelectrics is a fast phenomenon. In the present study it was found, however, that in semicrystalline ferroelectric polymers, containing both crystalline and amorphous phases, polarization continues to grow under an applied field during times 5-6 orders of magnitude longer than the reported switching times. It is demonstrated that the controversy can be resolved by taking into account the effect of conductivity in such materials. It is shown that there are two temporal contributions to the ferroelectric polarization, of which the first one is field dependent and originates from a fast alignment of dipoles in crystallites, while the second slow component is controlled by conductivity. Appropriate modeling reveals the importance of charge accumulated at the interfacial boundaries to form the slow ferroelectric polarization contribution. Good agreement of calculated and measured polarization has been observed for PVDF.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125595867","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
Voided polymer electrets - new materials, new challenges, new chances 聚合物空极体——新材料、新挑战、新机遇
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042939
R. Gerhard-Multhaupt
{"title":"Voided polymer electrets - new materials, new challenges, new chances","authors":"R. Gerhard-Multhaupt","doi":"10.1109/ISE.2002.1042939","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042939","url":null,"abstract":"In this review, the development of cellular propylene as an electret-transducer material since the mid-eighties is described, and the accompanying research into the origins of (quasi-)ferro-, pyro- and piezoelectric effects in voided polymer electrets is discussed in some detail. In this context, the most relevant charging and measuring techniques for piezo- and pyroelectric polymer-foam electrets are introduced. Porous fluoropolymer electrets and their investigation as single- or multiple-layer piezoelectrics are considered in view of their better thermal and temporal stabilities. Finally, some proposed applications of voided polymer electrets are mentioned.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132722746","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: 18
Study of magnetron sputtering of vanadium oxide thin films 氧化钒薄膜磁控溅射的研究
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1043014
Z.M. Wu, G. Xie, H. Mu, T. Wang, J.H. Xu, C.H. Huang, Y.D. Jiang
{"title":"Study of magnetron sputtering of vanadium oxide thin films","authors":"Z.M. Wu, G. Xie, H. Mu, T. Wang, J.H. Xu, C.H. Huang, Y.D. Jiang","doi":"10.1109/ISE.2002.1043014","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043014","url":null,"abstract":"In this paper, the influence of different sputtering processes on square resistance of thin films has been discussed; the temperature coefficient of resistance (TCR) and the square resistance R/spl square/ of thin films were tested and analyzed. The proper technology parameter is found. At last, the composition of the films was analyzed by the XPS.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"110 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131519828","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
Thermally stimulated depolarization current in ferroelectric blends of copolymers of vinylidene fluoride with trifluoroethylene 偏氟乙烯与三氟乙烯共聚物铁电共混物的热激退极化电流
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042945
B. Bai, X. Zhang, Z. Peng, H. Chan, C. Choy
{"title":"Thermally stimulated depolarization current in ferroelectric blends of copolymers of vinylidene fluoride with trifluoroethylene","authors":"B. Bai, X. Zhang, Z. Peng, H. Chan, C. Choy","doi":"10.1109/ISE.2002.1042945","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042945","url":null,"abstract":"Ferroelectric blends of vinylidene fluoride (VDF)/trifluoroethylene (TrFE) copolymer with different molar ratio of 56/44, 60/40, 63/37, 67/33, 70/30, 73/27 and 77/23 were fabricated by casting from methyl ethyl ketone solution. Thermally stimulated depolarization current (TSDC) of the samples has been measured using a modified thermal electric analyzer. Wide angle X-ray diffraction shows two peaks in the region of 2/spl theta/ = 18-20/spl deg/ for all the blends, which indicates that the blends have the same crystal lattice structures as the copolymers. DSC results show that the blends display the phase transition characteristics of both copolymers of 77/23 and 56/44. TSDC spectra of the blends also exhibits the characters of both components at different polarization temperatures.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115078801","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: 3
Physics of electromechanically active, cellular materials 电机械活性细胞物质的物理学
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042941
S. Bauer, S. Bauer-Gogonea, M. Dansachmulller, H. Hoislbauer, M. Lindner, R. Schwodiauer
{"title":"Physics of electromechanically active, cellular materials","authors":"S. Bauer, S. Bauer-Gogonea, M. Dansachmulller, H. Hoislbauer, M. Lindner, R. Schwodiauer","doi":"10.1109/ISE.2002.1042941","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042941","url":null,"abstract":"Cellular space-charge electrets have recently emerged as a new class of materials for electromechanical devices, offering chances for a wide range of applications and challenges for materials optimisation. However, many fundamental and applied aspects of the physics of these space-charge electrets are not yet fully explored. Here we summarise briefly our present understanding of the charging process and of the piezo- and pyroelectric response. In addition, wide-ranging similarities between cellular space-charge electrets and ferroelectric materials are outlined, especially switching of polarization and piezoelectricity.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114154357","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: 8
Photostimulated discharge of corona and electron-beam charged electret polymers 电晕和电子束带电驻极体聚合物的光刺激放电
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042932
A. Mellinger, F.C. Gonzalez, R. Gerhard-Multhaupt, L. F. Santos, R. Faria
{"title":"Photostimulated discharge of corona and electron-beam charged electret polymers","authors":"A. Mellinger, F.C. Gonzalez, R. Gerhard-Multhaupt, L. F. Santos, R. Faria","doi":"10.1109/ISE.2002.1042932","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042932","url":null,"abstract":"Despite the long-time use of space-charge electrets in various commercial applications, the mechanism of charge storage is still poorly understood. To study the energy distribution of deep traps, photostimulated discharge spectra of electron-beam and corona-charged polytetrafluoroethylene (PTFE), polyethylene terephthalate (PETP) and cellular polypropylene (PP) films were recorded for wavelengths between 200 and 400 nm. In addition, space-charge profiles were measured using the piezoelectrically generated pressure-step (PPS) method in order to monitor the detrapping process. Strong discharge currents of up to 15 pA/cm/sup 2/ were found in PETP around the UV absorption edge near 310 nm. Initial results show a quantitative depopulation of near-surface charges, whereas only partial detrapping could be achieved for bulk charges. Three distinct trapping levels could be identified in PP films.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125920037","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: 5
Fabrication and analysis of electret back-plates in microphones 麦克风驻极体背板的制作与分析
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1043016
X.S. Xie, C.B. Zhang, Z. Wu
{"title":"Fabrication and analysis of electret back-plates in microphones","authors":"X.S. Xie, C.B. Zhang, Z. Wu","doi":"10.1109/ISE.2002.1043016","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043016","url":null,"abstract":"This paper shows some technique about fabrication and analysis of electret back-plates in a kind of special microphones, which are used in measurement of sound wave. The sample of Teflon-FEP film (25 um thick) is deposited on the surface of the back-electrode of metal. Based on experimental results of the surface potential decay of electret samples, we use the method of high temperature extrapolation to calculate the active energy of trapped electrons. The result of experiments of surface potential decay is coincident with the theoretical analysis.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124830036","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: 1
Influence of alkyl chain length on dielectric relaxations in poly(n-alkyl methacrylates) 烷基链长对聚正烷基甲基丙烯酸酯介质弛豫的影响
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042948
E. Dudognon, A. Bernès, C. Lacabanne
{"title":"Influence of alkyl chain length on dielectric relaxations in poly(n-alkyl methacrylates)","authors":"E. Dudognon, A. Bernès, C. Lacabanne","doi":"10.1109/ISE.2002.1042948","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042948","url":null,"abstract":"Relations between chain structure and the dynamic of molecular movements are studied in the glass transition temperature range for a series of amorphous model polymers: the poly(n-alkyl methacrylates). Two dielectric spectroscopies are used in order to enlarge the accessible frequency range: the dynamic dielectric spectroscopy and the thermo-stimulated currents technique. We show the existence of three dipolar relaxation modes: the /spl alpha/ mode assigned to the glass relaxation, the /spl beta/ mode, a secondary relaxation mode, below Tg and the /spl alpha/' mode, above Tg, dielectric manifestation of the liquid-liquid transition. We follow the shift of these relaxations with frequency, determine the behaviour laws of relaxation times and the fine structure of these complex modes. From the comparison of these results, we identify the effect of the alkyl group length on the relaxations and we, propose a phenomenological model to describe the molecular mobility through the glass transition.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126018972","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
The study of the structure and optical properties of gellan-PVA, gellan-PVP and gellan-PVI composites 凝胶- pva、凝胶- pvp和凝胶- pvi复合材料的结构和光学性能研究
Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1043033
M. Strat, M. Popa, G. Strat, I.C. Alupei, S. Gurlui, I. Grecu
{"title":"The study of the structure and optical properties of gellan-PVA, gellan-PVP and gellan-PVI composites","authors":"M. Strat, M. Popa, G. Strat, I.C. Alupei, S. Gurlui, I. Grecu","doi":"10.1109/ISE.2002.1043033","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043033","url":null,"abstract":"The present study reports the results of an investigation on the preparation, characterisation and determination of optical properties of gellan-polyvinyl alcohol (PVA), gellan-poly (N-vinyl-pyrrolidone) (PVP) and gellan-poly (N-vinyl-imidazole) (PVI) composites and it represents a part of a major work dedicated to the development of new source of dielectric biomaterials for medical devices. The choice of PVA, PVP and PVI was based on the fact that their polymers are good electroactive synthetic polymers.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121706385","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
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