Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341512
A. Toureille, J. Reboul
Special-shaped PE samples as thin as 200 μm in their middle part and becoming thicker toward the edges have been machined from 3 cm thick slabs. Such samples have been charged under high DC voltage in the range of 20 kV, without any corona leakage. TSD studies have been carried out using both the common method and a new differential technique. An attempt of interpretation involving the assumption of a floating space charge according to Leal Ferreira's model agrees with our experimental results.
{"title":"High-voltage charging technique and TSD studies of polyethylene thermo-electrets\"","authors":"A. Toureille, J. Reboul","doi":"10.1109/ISE.1985.7341512","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341512","url":null,"abstract":"Special-shaped PE samples as thin as 200 μm in their middle part and becoming thicker toward the edges have been machined from 3 cm thick slabs. Such samples have been charged under high DC voltage in the range of 20 kV, without any corona leakage. TSD studies have been carried out using both the common method and a new differential technique. An attempt of interpretation involving the assumption of a floating space charge according to Leal Ferreira's model agrees with our experimental results.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"7 1","pages":"386-392"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81799838","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}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341506
M. Lal, R. Parshad
A new mechanism of charge decay of electrets is proposed. In this mechanism the observed charge decay is only apparent and due to screening (not cancellation) of the electret charge at the atomic or microscopic level by electrical charges drawn from ions in the atmosphere or by electrical loading. The water film on the electret and the finite conductivity of the material constitute forms of electrical loading. The Cancellation of charge is avoided by the free charge being isolated in traps or the charge being due to exposed ends of aligned dipoles or both. It has been possible to evolve a process, essentially based on contacting each of the electret surfaces, one at a time, to a metal plate, to remove the screening charge and thus activate the (apparently) decayed electret, thus making life of the treated electrets almost infinite.
{"title":"A suggested new mechanism of charge decay of electrets and its application to their charge recovery","authors":"M. Lal, R. Parshad","doi":"10.1109/ISE.1985.7341506","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341506","url":null,"abstract":"A new mechanism of charge decay of electrets is proposed. In this mechanism the observed charge decay is only apparent and due to screening (not cancellation) of the electret charge at the atomic or microscopic level by electrical charges drawn from ions in the atmosphere or by electrical loading. The water film on the electret and the finite conductivity of the material constitute forms of electrical loading. The Cancellation of charge is avoided by the free charge being isolated in traps or the charge being due to exposed ends of aligned dipoles or both. It has been possible to evolve a process, essentially based on contacting each of the electret surfaces, one at a time, to a metal plate, to remove the screening charge and thus activate the (apparently) decayed electret, thus making life of the treated electrets almost infinite.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"39 1","pages":"352-357"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74336699","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}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341596
F. Bauer, Klaus Harnischmacher, Jacques Riha
Polyvinylidene fluoride PVF2 and VF2/C2F3H copolytners present strong piezoelectric activities under specific conditions of crystallization and polarization. The piezoelectric activity of PVF2 depends on the polarization process as it is presented in the hysteresis loops P(E) (P polarization, E electrical field). The remanent polarization attains 10 p.C/cm2 for biaxially stretched PVF2 films. Results obtained on VF2/C2F3H copolymers are also reported. Properties of these well clean and uniform poled ferroelectric materials, under static, dynamic pressure and shock wave action are presented and discussed. These organic piezoelectric materials are strong candidates for shock gauges and new transducers.
{"title":"Ferroelectric polarization of PVF2 and VF2/C2F3H copolymers: Piezoelectric properties under dynamic pressure and shock loading","authors":"F. Bauer, Klaus Harnischmacher, Jacques Riha","doi":"10.1109/ISE.1985.7341596","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341596","url":null,"abstract":"Polyvinylidene fluoride PVF<inf>2</inf> and VF<inf>2</inf>/C<inf>2</inf>F<inf>3</inf>H copolytners present strong piezoelectric activities under specific conditions of crystallization and polarization. The piezoelectric activity of PVF<inf>2</inf> depends on the polarization process as it is presented in the hysteresis loops P(E) (P polarization, E electrical field). The remanent polarization attains 10 p.C/cm<sup>2</sup> for biaxially stretched PVF<inf>2</inf> films. Results obtained on VF<inf>2</inf>/C<inf>2</inf>F<inf>3</inf>H copolymers are also reported. Properties of these well clean and uniform poled ferroelectric materials, under static, dynamic pressure and shock wave action are presented and discussed. These organic piezoelectric materials are strong candidates for shock gauges and new transducers.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"10 1","pages":"924-929"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90928953","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}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341551
Ž. Jelčić, F. Ranogajec
The thermally stimulated depolarization(TSD) currents of unsaturated polyester(UP) resin thermoelectrets have been measured in the low temperature range. The study of the decrease of the current intensity as a function of the absorbed dose reveals important differences between the peaks of the spectrum; the low temperature peaks can be attributed to dipolar volume polarization, and £he high temperature peaks to an ionic space charge polarization. The shift of the peaks may be indicative of plasticization of the polyester by styrene, and of restriction upon motions of the chain imposed by the crosslinks. The l-peak could be manifestation of the liquid-liquid(Tll) transition, from the Tll/Tg ratio, and here it corresponds to the thermally activated disintegration of phase separated structures, which were well documented in the inherently heterogeneous UP resins.
{"title":"Radiation crosslinking effect on thermally stimulated current spectra of unsaturated polyester resins","authors":"Ž. Jelčić, F. Ranogajec","doi":"10.1109/ISE.1985.7341551","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341551","url":null,"abstract":"The thermally stimulated depolarization(TSD) currents of unsaturated polyester(UP) resin thermoelectrets have been measured in the low temperature range. The study of the decrease of the current intensity as a function of the absorbed dose reveals important differences between the peaks of the spectrum; the low temperature peaks can be attributed to dipolar volume polarization, and £he high temperature peaks to an ionic space charge polarization. The shift of the peaks may be indicative of plasticization of the polyester by styrene, and of restriction upon motions of the chain imposed by the crosslinks. The l-peak could be manifestation of the liquid-liquid(Tll) transition, from the Tll/Tg ratio, and here it corresponds to the thermally activated disintegration of phase separated structures, which were well documented in the inherently heterogeneous UP resins.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"42 1","pages":"648-652"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84761350","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}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341581
M. G. Bridelli, R. Capelletti, G. Ruani, A. Vecli
The role of water in a bioelectret such as lysozyme at different hydration levels is studied by coupling TSDC and i.r. absorption measurements. In addition to the 312 K-band reported by Mascarenhas, our TSDC spectra exhibit new, weaker but anyway relevant bands related to water in different coordinations. At fixed starting hydration levels, the time evolution of water contents was studied by isothermal sample aging in dynamic vacuum: 1) the whole TSDC spectrum was reduced, the decrease being more relevant on the high temperature side and 2) the water related i.r. bands decreased as well.
{"title":"Water induced bioelectret state in lysozyme","authors":"M. G. Bridelli, R. Capelletti, G. Ruani, A. Vecli","doi":"10.1109/ISE.1985.7341581","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341581","url":null,"abstract":"The role of water in a bioelectret such as lysozyme at different hydration levels is studied by coupling TSDC and i.r. absorption measurements. In addition to the 312 K-band reported by Mascarenhas, our TSDC spectra exhibit new, weaker but anyway relevant bands related to water in different coordinations. At fixed starting hydration levels, the time evolution of water contents was studied by isothermal sample aging in dynamic vacuum: 1) the whole TSDC spectrum was reduced, the decrease being more relevant on the high temperature side and 2) the water related i.r. bands decreased as well.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"8 1","pages":"831-835"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81511899","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}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341600
J. Paul
The first theory of feroelectric was produced by Devonshire in 1949, and a new approach proposed 10 years later by Cochran, linking fereelectric phenomena to the theory of elasticity in crystals. However, the metro-scopic mechanism responsinle for spontaneous polarization still remain largely unknown. In this paper a new technique has been proposed to increase the local field and a mathematical model has been presented together with theoretical analysis.
{"title":"Behaviour of ferroelectric materials under the influence of magnetic field","authors":"J. Paul","doi":"10.1109/ISE.1985.7341600","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341600","url":null,"abstract":"The first theory of feroelectric was produced by Devonshire in 1949, and a new approach proposed 10 years later by Cochran, linking fereelectric phenomena to the theory of elasticity in crystals. However, the metro-scopic mechanism responsinle for spontaneous polarization still remain largely unknown. In this paper a new technique has been proposed to increase the local field and a mathematical model has been presented together with theoretical analysis.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"11 1","pages":"947-951"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81996647","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}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341456
S. Mascarenhas
When B.Gross arrived in Rio de Janeiro in Brazil in 19 33 he was a young Ph.D. from Stuttgart full of enthusiasm and creativity. He was about to start the tradition of physical research in Brazil and also provide one of the most important examples of scientific development in Latin America. His work however was not to be confined only to Brazil. Due to his multiple interests and high quality of his researches, Gross extended his contributions to an international level, and there is no better proof of the importance of his work than this International Symposium, ISEV, in good time organized by G. Sessler to honour Gross and continue the series started in Chicago in 1967 with the inspiration of M.Perlman. In 1975 in S. Carlos, Brazil another Symposium was organized to honour Gross on his seventieth anniversary. One decade later in this Symposium to commemorate his 80th anniversary, Gross has published more than 25 papers and his enthusiasm and creativity are an example for many generations of physicists present in ISE V. There are many aspects of the life of B.Gross that are unique as man and scientist. I would like to mention some of these many facets of his personality here, withouth bothering to separate systematically his scientific acomplishements from his life as a human being. Perhaps this is the better way to speak about Gross.
{"title":"\"Bernhard gross: The man and the scientist\"","authors":"S. Mascarenhas","doi":"10.1109/ISE.1985.7341456","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341456","url":null,"abstract":"When B.Gross arrived in Rio de Janeiro in Brazil in 19 33 he was a young Ph.D. from Stuttgart full of enthusiasm and creativity. He was about to start the tradition of physical research in Brazil and also provide one of the most important examples of scientific development in Latin America. His work however was not to be confined only to Brazil. Due to his multiple interests and high quality of his researches, Gross extended his contributions to an international level, and there is no better proof of the importance of his work than this International Symposium, ISEV, in good time organized by G. Sessler to honour Gross and continue the series started in Chicago in 1967 with the inspiration of M.Perlman. In 1975 in S. Carlos, Brazil another Symposium was organized to honour Gross on his seventieth anniversary. One decade later in this Symposium to commemorate his 80th anniversary, Gross has published more than 25 papers and his enthusiasm and creativity are an example for many generations of physicists present in ISE V. There are many aspects of the life of B.Gross that are unique as man and scientist. I would like to mention some of these many facets of his personality here, withouth bothering to separate systematically his scientific acomplishements from his life as a human being. Perhaps this is the better way to speak about Gross.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"32 1","pages":"3-8"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85486030","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}
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