Pub Date : 1994-08-07DOI: 10.1109/ISAF.1994.522299
J. Benedetto, M. Roush, I. Lloyd, R. Ramesh
The ferroelectric imprint is measured on thin-film PLZT capacitors with lanthanum strontium cobalt oxide top and bottom electrodes. The data show a significant amount of imprint with a combined elevated temperature and alternating (unipolar) voltage stress. No imprint was observed on samples that were temperature stressed without external bias.
{"title":"Imprint of ferroelectric PLZT thin-film capacitors with lanthanum strontium cobalt oxide electrodes","authors":"J. Benedetto, M. Roush, I. Lloyd, R. Ramesh","doi":"10.1109/ISAF.1994.522299","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522299","url":null,"abstract":"The ferroelectric imprint is measured on thin-film PLZT capacitors with lanthanum strontium cobalt oxide top and bottom electrodes. The data show a significant amount of imprint with a combined elevated temperature and alternating (unipolar) voltage stress. No imprint was observed on samples that were temperature stressed without external bias.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"160 1","pages":"66-69"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76937515","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522383
Z. Gui, W. Zhong, S. Dong, Longtu Li, Xiaowen Zhang
A quarternary system ceramic with high piezoelectric constants, particularly a high d/sub 31/ and high d/sub 33/, was studied. The composition of the materials is PMN-PNN-PZT doped with oxides of Sr, Bi, Sn and La etc. The properties of the materials are as follow: d/sub 33/=(600-750)10/sup -12/C/N, d/sub 31/=(-300-398)/spl times/10/sup -12/C/N, Kp=0.68-0.75. By using this material, a new type of rotational stepper motor, a piezoelectric electro-rheological motor had been made. This kind of motor has unique advantages: no vibration noise, zero wear, low consumed power, large travel range and high resolution etc.
{"title":"Investigation on piezoelectric ceramics with high d/sub 33/, d/sub 31/ for a new type of rotational stepper motor","authors":"Z. Gui, W. Zhong, S. Dong, Longtu Li, Xiaowen Zhang","doi":"10.1109/ISAF.1994.522383","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522383","url":null,"abstract":"A quarternary system ceramic with high piezoelectric constants, particularly a high d/sub 31/ and high d/sub 33/, was studied. The composition of the materials is PMN-PNN-PZT doped with oxides of Sr, Bi, Sn and La etc. The properties of the materials are as follow: d/sub 33/=(600-750)10/sup -12/C/N, d/sub 31/=(-300-398)/spl times/10/sup -12/C/N, Kp=0.68-0.75. By using this material, a new type of rotational stepper motor, a piezoelectric electro-rheological motor had been made. This kind of motor has unique advantages: no vibration noise, zero wear, low consumed power, large travel range and high resolution etc.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"39 1","pages":"387-389"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81356430","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522366
G. Haertling
On-going studies have shown that the PLZT I compositional system is one which yields materials possessing some of the highest coefficients for piezoelectric and electrostrictive actuators. It has also been found that PLZT ceramics are near ideal for achieving the ultra-high displacements recently reported for the Rainbow (Reduced and INternally Biased Oxide Wafer) actuators. In order to determine the optimum composition or compositions for these Rainbow actuators, a study was conducted by preparing and processing selected formulations throughout the PLZT system. Results from this study indicate that, like the conventional direct extensional-mode materials, the maximum Rainbow bending displacements occur in materials located compositionally at the morphotropic (FE/sub rhomb/-FE/sub ter/) and Curie point (FE-PE, PE-AFE) phase boundaries. Examples of specific compositions for each of these regions are 2/53/47, 9/65/35 and 8.5/70/30 (La/Zr/Ti), respectively. Microstructural (grain size), electrical (dielectric constant, dissipation factor) and electromechanical (axial displacement) data are presented for selected compositions in the system.
{"title":"Compositional study of PLZT rainbow ceramics for piezo actuators","authors":"G. Haertling","doi":"10.1109/ISAF.1994.522366","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522366","url":null,"abstract":"On-going studies have shown that the PLZT I compositional system is one which yields materials possessing some of the highest coefficients for piezoelectric and electrostrictive actuators. It has also been found that PLZT ceramics are near ideal for achieving the ultra-high displacements recently reported for the Rainbow (Reduced and INternally Biased Oxide Wafer) actuators. In order to determine the optimum composition or compositions for these Rainbow actuators, a study was conducted by preparing and processing selected formulations throughout the PLZT system. Results from this study indicate that, like the conventional direct extensional-mode materials, the maximum Rainbow bending displacements occur in materials located compositionally at the morphotropic (FE/sub rhomb/-FE/sub ter/) and Curie point (FE-PE, PE-AFE) phase boundaries. Examples of specific compositions for each of these regions are 2/53/47, 9/65/35 and 8.5/70/30 (La/Zr/Ti), respectively. Microstructural (grain size), electrical (dielectric constant, dissipation factor) and electromechanical (axial displacement) data are presented for selected compositions in the system.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"103 1","pages":"313-318"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87067717","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522308
W. Xue, P. Lu, W. Huebner
Modified lead titanate ceramics with a composition of (Pb/sub 0.88-x/Ca/sub x/Sm/sub 0.08/)(Ti/sub 0.98/Mn/sub 0.02/)O/sub 3/; x=0.11, 0.13, 0.15 and 0.17 were prepared. Simultaneous doping of samarium and calcium resulted in normal ferroelectric behavior, i.e. The dielectric properties changed in a manner typically associated with isovalent shifting of the Curie temperature. However, the unique attribute of this system appeared for the x=0.13 and 0.15 compositions, which exhibited k/sub t/'s /spl ges/57%.
{"title":"Effect of calcia additions on the electromechanical properties of samarium-modified lead titanate ceramics","authors":"W. Xue, P. Lu, W. Huebner","doi":"10.1109/ISAF.1994.522308","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522308","url":null,"abstract":"Modified lead titanate ceramics with a composition of (Pb/sub 0.88-x/Ca/sub x/Sm/sub 0.08/)(Ti/sub 0.98/Mn/sub 0.02/)O/sub 3/; x=0.11, 0.13, 0.15 and 0.17 were prepared. Simultaneous doping of samarium and calcium resulted in normal ferroelectric behavior, i.e. The dielectric properties changed in a manner typically associated with isovalent shifting of the Curie temperature. However, the unique attribute of this system appeared for the x=0.13 and 0.15 compositions, which exhibited k/sub t/'s /spl ges/57%.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"64 1","pages":"101-104"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87144486","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522371
L. Brown, J. Scheinbeim, B. Newman
The first measurements of high frequency dielectric and thickness-mode electromechanical properties of ferroelectric nylons are reported. Two sets of nylon 11 film samples were produced. The first set was melt-quenched and poled, while the second set was melt-quenched and then cold-drawn at room temperature before poling, resulting in a three-dimensionally ordered sample. Gold electrodes, 10 mm by 10 mm, were evaporated on opposing sample surfaces. The remanent polarization of the unoriented sample was 27 mC/m/sup 2/ while that of the oriented sample was 52 mC/m/sup 2/. Samples of each film were placed in a programmable environmental chamber and connected to a Hewlett Packard 4195A Network/impedance Analyzer via a custom remote fixture. Broadband measurements were made of the clamped capacitance and dissipation factor, thickness-mode electromechanical coupling coefficient k/sub t/, mechanical quality factor Q/sub m/, and longitudinal sound velocity v/sub l/ for each sample over a temperature range of 20/spl deg/-160/spl deg/C. Comparisons of the properties were made between oriented and unoriented film samples. The results showed k/sub t/ values in the 0.03-0.11 range, and Q/sub m/ values of 8-10 above the glass transition temperatures of the samples (approximately 60-70/spl deg/C). The results show promise for high temperature ferroelectric nylon sensing applications.
{"title":"High frequency dielectric and electromechanical properties of ferroelectric nylons","authors":"L. Brown, J. Scheinbeim, B. Newman","doi":"10.1109/ISAF.1994.522371","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522371","url":null,"abstract":"The first measurements of high frequency dielectric and thickness-mode electromechanical properties of ferroelectric nylons are reported. Two sets of nylon 11 film samples were produced. The first set was melt-quenched and poled, while the second set was melt-quenched and then cold-drawn at room temperature before poling, resulting in a three-dimensionally ordered sample. Gold electrodes, 10 mm by 10 mm, were evaporated on opposing sample surfaces. The remanent polarization of the unoriented sample was 27 mC/m/sup 2/ while that of the oriented sample was 52 mC/m/sup 2/. Samples of each film were placed in a programmable environmental chamber and connected to a Hewlett Packard 4195A Network/impedance Analyzer via a custom remote fixture. Broadband measurements were made of the clamped capacitance and dissipation factor, thickness-mode electromechanical coupling coefficient k/sub t/, mechanical quality factor Q/sub m/, and longitudinal sound velocity v/sub l/ for each sample over a temperature range of 20/spl deg/-160/spl deg/C. Comparisons of the properties were made between oriented and unoriented film samples. The results showed k/sub t/ values in the 0.03-0.11 range, and Q/sub m/ values of 8-10 above the glass transition temperatures of the samples (approximately 60-70/spl deg/C). The results show promise for high temperature ferroelectric nylon sensing applications.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"35 1","pages":"337-340"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86624489","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522492
T. Li, T. Kido, J. Adair
Electro-optical characteristics of inorganic colloid particles dispersed in organic solvent are discussed as well as its potential applications related to Suspended Particle Displays (SPDs).
讨论了分散在有机溶剂中的无机胶体粒子的电光特性及其在悬浮粒子显示器(SPDs)中的潜在应用。
{"title":"Suspended particle flat panel displays using colloidal particles","authors":"T. Li, T. Kido, J. Adair","doi":"10.1109/ISAF.1994.522492","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522492","url":null,"abstract":"Electro-optical characteristics of inorganic colloid particles dispersed in organic solvent are discussed as well as its potential applications related to Suspended Particle Displays (SPDs).","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"33 1","pages":"791-793"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83125234","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522460
Feiling Wang, G. Haertling
We report a reflective thin film ferroelectric light modulator which has exhibited optical phase modulation as large as fifty degrees and on/off signal ratio of twenty for intensity modulation. The large optical modulation was achieved by means of multiple reflection. A ferroelectric (FE) PLZT thin film material, deposited on Pt-coated silicon substrate, was used as the modulating medium. An indium-tin oxide (ITO) thin layer was deposited on the ferroelectric films as the top electrode. A He-Ne laser beam was obliquely incident on the ITO/FE/Pt structure. The light modulation was detected in the laser beam reflected from the thin film structure when a voltage signal was applied to the ITO and Pt electrodes. Unlike transmission-mode modulators, the sandwich of the ferroelectric films between the air-ITO and FE-Pt interfaces exhibited characteristics of a Fabry-Perot etalon. Near a Fabry-Perot peak, drastically enhanced light modulation than transmission devices was obtained. Design principles and the performance of the modulator are discussed.
{"title":"Large electrooptic modulation using ferroelectric thin films in a Fabry-Perot cavity","authors":"Feiling Wang, G. Haertling","doi":"10.1109/ISAF.1994.522460","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522460","url":null,"abstract":"We report a reflective thin film ferroelectric light modulator which has exhibited optical phase modulation as large as fifty degrees and on/off signal ratio of twenty for intensity modulation. The large optical modulation was achieved by means of multiple reflection. A ferroelectric (FE) PLZT thin film material, deposited on Pt-coated silicon substrate, was used as the modulating medium. An indium-tin oxide (ITO) thin layer was deposited on the ferroelectric films as the top electrode. A He-Ne laser beam was obliquely incident on the ITO/FE/Pt structure. The light modulation was detected in the laser beam reflected from the thin film structure when a voltage signal was applied to the ITO and Pt electrodes. Unlike transmission-mode modulators, the sandwich of the ferroelectric films between the air-ITO and FE-Pt interfaces exhibited characteristics of a Fabry-Perot etalon. Near a Fabry-Perot peak, drastically enhanced light modulation than transmission devices was obtained. Design principles and the performance of the modulator are discussed.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"19 1","pages":"683-686"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79080061","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522369
Q.M. Zhang, X. Geng, Y. Shui, W. Cao, L. E. Cross
A dynamic theory is developed for piezocomposites with 2-2 connectivity. By solving the coupled dynamic equations in the piezoceramic plate and polymer region subjected to the boundary conditions at the ceramic-polymer interface, the distributions of the elastic and electric variables in a composite are obtained. The electromechanical coupling factor, the acoustic impedance, the resonant frequency, and the elastic coupling between the polymer and ceramic at the thickness resonance can be determined. The effects of mode coupling on the thickness resonance and lateral resonance are elucidated and the dependence of the frequency of these resonant modes on the composite thickness can be estimated. Theoretical results are compared with experimental observations.
{"title":"Ultrasonic piezoceramic-polymer composite transducer-dynamic behavior and effects of heterogeneous structure","authors":"Q.M. Zhang, X. Geng, Y. Shui, W. Cao, L. E. Cross","doi":"10.1109/ISAF.1994.522369","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522369","url":null,"abstract":"A dynamic theory is developed for piezocomposites with 2-2 connectivity. By solving the coupled dynamic equations in the piezoceramic plate and polymer region subjected to the boundary conditions at the ceramic-polymer interface, the distributions of the elastic and electric variables in a composite are obtained. The electromechanical coupling factor, the acoustic impedance, the resonant frequency, and the elastic coupling between the polymer and ceramic at the thickness resonance can be determined. The effects of mode coupling on the thickness resonance and lateral resonance are elucidated and the dependence of the frequency of these resonant modes on the composite thickness can be estimated. Theoretical results are compared with experimental observations.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"29 1","pages":"329-332"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87222562","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522479
S. Gridnev, N.G. Pavlova, S. P. Rogova
This paper reports a detailed study of the electrostrictive effect and related properties of unpoled ferroelectric ceramics (1-x)/spl middot/PbZrO/sub 3/-x/spl middot/K/sub 0.5/Bi/sub 0.5/TiO/sub 3/, where x=0-1, using a sensitive capacitance dilatometer at room temperature. The material was found to exhibit a large electrostrictive coefficient Q/sub 11/ of /spl sime/0.3 m/sup 4//C/sup 2/ which is more than three times as large as that of single crystal BaTiO/sub 3/. Comparison with PZT ceramics indicates that new material is a potentially useful one for transducer application.
{"title":"Electrostrictive properties of PbZrO/sub 3/-K/sub 0.5/Bi/sub 0.5/TiO/sub 3/ ceramics","authors":"S. Gridnev, N.G. Pavlova, S. P. Rogova","doi":"10.1109/ISAF.1994.522479","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522479","url":null,"abstract":"This paper reports a detailed study of the electrostrictive effect and related properties of unpoled ferroelectric ceramics (1-x)/spl middot/PbZrO/sub 3/-x/spl middot/K/sub 0.5/Bi/sub 0.5/TiO/sub 3/, where x=0-1, using a sensitive capacitance dilatometer at room temperature. The material was found to exhibit a large electrostrictive coefficient Q/sub 11/ of /spl sime/0.3 m/sup 4//C/sup 2/ which is more than three times as large as that of single crystal BaTiO/sub 3/. Comparison with PZT ceramics indicates that new material is a potentially useful one for transducer application.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"20 1","pages":"753-754"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91053900","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 : 1994-08-07DOI: 10.1109/ISAF.1994.522474
H. Yamamoto, A. Shibata, K. Hajime, F. Takao, K. Sugisawa, Y. Niwatsukino, H. Shishiba, Shigeto Takeda
Several requirements for NTC thermistors used for office automation (OA) equipment and home electronics are small size, high sensitivity and high reliability. Commonly used NTC thermistors do not have adequate reliability against thermal shock. Size reduction is difficult due to the multi-phase structure and porosity in ceramics. It is also difficult to realize the required properties because the resistivity-B value relationship control method has not been established. So we have developed a method to control the properties of NTC thermistor by controlling the numbers and the valence of solid solution ions on A and B sites in the single phase spinel structure. Based on these methods, we have also established a method to make a more dense structure. A NTC thermistor series has been developed possessing small size, high sensitivity and high reliability.
{"title":"The development of high sensitivity NTC thermistors","authors":"H. Yamamoto, A. Shibata, K. Hajime, F. Takao, K. Sugisawa, Y. Niwatsukino, H. Shishiba, Shigeto Takeda","doi":"10.1109/ISAF.1994.522474","DOIUrl":"https://doi.org/10.1109/ISAF.1994.522474","url":null,"abstract":"Several requirements for NTC thermistors used for office automation (OA) equipment and home electronics are small size, high sensitivity and high reliability. Commonly used NTC thermistors do not have adequate reliability against thermal shock. Size reduction is difficult due to the multi-phase structure and porosity in ceramics. It is also difficult to realize the required properties because the resistivity-B value relationship control method has not been established. So we have developed a method to control the properties of NTC thermistor by controlling the numbers and the valence of solid solution ions on A and B sites in the single phase spinel structure. Based on these methods, we have also established a method to make a more dense structure. A NTC thermistor series has been developed possessing small size, high sensitivity and high reliability.","PeriodicalId":20488,"journal":{"name":"Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics","volume":"33 1","pages":"735-738"},"PeriodicalIF":0.0,"publicationDate":"1994-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91149995","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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