Pub Date : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364447
C. Shu, Liang Wang, Jiamei Jin, Jian-hui Zhang
A novel tracked travelling system driven by a Langevin piezoelectric transducer is proposed. It has advantages of large driving force, high mechanical integration, well reliability, requiring no lubrication, and having the potential application in planetary exploration. The tracked travelling system comprises of an actuating mechanism and a track. The actuating mechanism includes a Langevin piezoelectric transducer and two annular parts symmetrically placed at two ends of the transducer. The track is pressed in contact to the outer surfaces of the annular parts. Traveling rotating waves are generated in two annular parts, and then the microscopic elliptical motions at the outer surface of the annular parts will be generated to drive the track to move by friction force. The actuating mechanism is analyzed by using FEM, and the simulation results are compared with the vibration measurements results. And then the prototype of the tracked travelling system was assembled and investigated experimentally for its performance. The maximum average velocities to bi-directional movements were 72mm/s and 61.5mm/s under the excitation voltage of 500Vpp and frequency of 35.1 kHz, respectively.
{"title":"A Langevin type piezoelectric tracked travelling system","authors":"C. Shu, Liang Wang, Jiamei Jin, Jian-hui Zhang","doi":"10.1109/SPAWDA.2015.7364447","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364447","url":null,"abstract":"A novel tracked travelling system driven by a Langevin piezoelectric transducer is proposed. It has advantages of large driving force, high mechanical integration, well reliability, requiring no lubrication, and having the potential application in planetary exploration. The tracked travelling system comprises of an actuating mechanism and a track. The actuating mechanism includes a Langevin piezoelectric transducer and two annular parts symmetrically placed at two ends of the transducer. The track is pressed in contact to the outer surfaces of the annular parts. Traveling rotating waves are generated in two annular parts, and then the microscopic elliptical motions at the outer surface of the annular parts will be generated to drive the track to move by friction force. The actuating mechanism is analyzed by using FEM, and the simulation results are compared with the vibration measurements results. And then the prototype of the tracked travelling system was assembled and investigated experimentally for its performance. The maximum average velocities to bi-directional movements were 72mm/s and 61.5mm/s under the excitation voltage of 500Vpp and frequency of 35.1 kHz, respectively.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126313534","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364527
W. Yan, Cunyue Lu, Fei Shen, Chong Li, Z. Huang
A novel actuator-driven powder transport system is proposed in this paper. It has two sets of piezoelectric ceramic stacks whose vibrations couple together and make the powder transport pipe do elliptical vibration. The powder on the pipe wall can be thrown up, leading to the relative motions between the powder and pipe wall and thus the powder is transported. To get higher transport efficiency and speed, a displacement amplifier is adopted. The movement of the whole system is analyzed and discussed in theory and the mathematic model is established. The relationship between the input voltage and the output speed is obtained by means of simulation analysis. Theory foundation is provided for further study and practical application.
{"title":"A powder transport system based on piezoelectric ceramic stack actuators","authors":"W. Yan, Cunyue Lu, Fei Shen, Chong Li, Z. Huang","doi":"10.1109/SPAWDA.2015.7364527","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364527","url":null,"abstract":"A novel actuator-driven powder transport system is proposed in this paper. It has two sets of piezoelectric ceramic stacks whose vibrations couple together and make the powder transport pipe do elliptical vibration. The powder on the pipe wall can be thrown up, leading to the relative motions between the powder and pipe wall and thus the powder is transported. To get higher transport efficiency and speed, a displacement amplifier is adopted. The movement of the whole system is analyzed and discussed in theory and the mathematic model is established. The relationship between the input voltage and the output speed is obtained by means of simulation analysis. Theory foundation is provided for further study and practical application.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122263033","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364510
Jingtong Zhang, H. Tzou
The phenomenon of stress induced by inhomogeneous electric field is known as the converse flexoelectric effect. It can be used in precision actuation and control applications. In this study, a line electrode is used to actuate a flexoelectric cylindrical shell panel based on the converse flexoelectric effect. The influences of different parameters to modal actuation effects are studied. It shows that when the cylindrical shell panel changes its geometries, e.g., length, thickness, curvature angle, etc., both the panel stiffness and the distribution of electric field, which related to induced flexoelectric control moment and membrane force, also change. And as the increase of panel's thickness, actuation effect decreases. But the increase of panel's curvature angle and length enhances the actuation effect.
{"title":"Actuation of flexoelectric cylindrical shell panel with line electrodes","authors":"Jingtong Zhang, H. Tzou","doi":"10.1109/SPAWDA.2015.7364510","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364510","url":null,"abstract":"The phenomenon of stress induced by inhomogeneous electric field is known as the converse flexoelectric effect. It can be used in precision actuation and control applications. In this study, a line electrode is used to actuate a flexoelectric cylindrical shell panel based on the converse flexoelectric effect. The influences of different parameters to modal actuation effects are studied. It shows that when the cylindrical shell panel changes its geometries, e.g., length, thickness, curvature angle, etc., both the panel stiffness and the distribution of electric field, which related to induced flexoelectric control moment and membrane force, also change. And as the increase of panel's thickness, actuation effect decreases. But the increase of panel's curvature angle and length enhances the actuation effect.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115089480","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364478
Yan-lu Feng, Mengwei Liu, Xin Li, Jian Li
In this paper, an Al-ZnO-Al film bulk acoustic resonator (FBAR) is described, which has a high mass sensitivity. And the series resonant frequency (fs) and parallel resonant frequency (fP) of the micromachined FBAR have been measured by using a network analyzer, which are 1.546 GHz and 1.590 GHz, respectively (close to the theoretical value simulated by mason equivalent circuit model). Moreover, the effective electromechanical coupling coefficient (Keff2) and quality Q have been calculated to be 6.83% and 350, respectively. After the FBAR packaging, the mass loading was added on the FBAR backside surface by sputtering different thicknesses of ZnO layer. From the graph of the resonant frequency versus added ZnO thickness, the FBAR is measured to have a mass sensitivity Sm of 1116.55 cm2 / g. The result is almost agreed with the theoretical value of 1166.86 cm2 / g, which is about 80 times of the conventional quartz crystal microbalance (QCM).
{"title":"Micromachined mass sensor based on film bulk acoustic resonator","authors":"Yan-lu Feng, Mengwei Liu, Xin Li, Jian Li","doi":"10.1109/SPAWDA.2015.7364478","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364478","url":null,"abstract":"In this paper, an Al-ZnO-Al film bulk acoustic resonator (FBAR) is described, which has a high mass sensitivity. And the series resonant frequency (fs) and parallel resonant frequency (fP) of the micromachined FBAR have been measured by using a network analyzer, which are 1.546 GHz and 1.590 GHz, respectively (close to the theoretical value simulated by mason equivalent circuit model). Moreover, the effective electromechanical coupling coefficient (Keff2) and quality Q have been calculated to be 6.83% and 350, respectively. After the FBAR packaging, the mass loading was added on the FBAR backside surface by sputtering different thicknesses of ZnO layer. From the graph of the resonant frequency versus added ZnO thickness, the FBAR is measured to have a mass sensitivity Sm of 1116.55 cm2 / g. The result is almost agreed with the theoretical value of 1166.86 cm2 / g, which is about 80 times of the conventional quartz crystal microbalance (QCM).","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"37 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121008655","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364450
Fei Han, Jun-hui Hu
With the progress of the R&D of medical technology, ultrasound has been widely used in the treatment of various diseases. However, the details of sound field in a human head acoustically excited are still not very clear. In this work, we have revealed the dependency of intracranial sound field and skull stress on the location and frequency of the excitation, and on the head size by the FEM. The low-frequency ultrasound (<100 kHz) can well penetrate into the brain, and MHz ultrasound almost cannot penetrate into the brain. Ultrasonic energy tends to exist near the inner surface of the skull in the frequency range for ultrasonic therapies (500 kHz–2.5MHz). As the head size decreases, the ultrasonic energy goes deeper into the brain, and intracranial sound pressure increases sharply when the head size is less than half of the standard one.
{"title":"Distribution and strength of sound in the human head","authors":"Fei Han, Jun-hui Hu","doi":"10.1109/SPAWDA.2015.7364450","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364450","url":null,"abstract":"With the progress of the R&D of medical technology, ultrasound has been widely used in the treatment of various diseases. However, the details of sound field in a human head acoustically excited are still not very clear. In this work, we have revealed the dependency of intracranial sound field and skull stress on the location and frequency of the excitation, and on the head size by the FEM. The low-frequency ultrasound (<100 kHz) can well penetrate into the brain, and MHz ultrasound almost cannot penetrate into the brain. Ultrasonic energy tends to exist near the inner surface of the skull in the frequency range for ultrasonic therapies (500 kHz–2.5MHz). As the head size decreases, the ultrasonic energy goes deeper into the brain, and intracranial sound pressure increases sharply when the head size is less than half of the standard one.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121054794","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}
Multilayer actuators with twenty-six 0.7mm-layers (18mm×18mm×10mm) of lead zirconate titanate (PZT-4) were made and tested. These actuators were fabricated in the laboratory with simple techniques and cost low. The new fabrication method not only greatly reduced the cost of piezoelectric stack, but also made it possible to obtain any required size of piezoelectric stacks in the laboratory. A micro-displacement amplifier to match the fabricated multilayer actuators is also designed, fabricated and test. Experiment results show that the micro-displacement amplifier can obtain a peak to peak displacement of 160 um under the quasi-static condition.
{"title":"Design and fabrication of a large displacement piezoelectric actuator","authors":"Qiaosheng Pan, Yongbin Liu, Yu-hai Liu, Li-jiao Gong, Liangguo He, Z. Feng","doi":"10.1109/SPAWDA.2015.7364485","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364485","url":null,"abstract":"Multilayer actuators with twenty-six 0.7mm-layers (18mm×18mm×10mm) of lead zirconate titanate (PZT-4) were made and tested. These actuators were fabricated in the laboratory with simple techniques and cost low. The new fabrication method not only greatly reduced the cost of piezoelectric stack, but also made it possible to obtain any required size of piezoelectric stacks in the laboratory. A micro-displacement amplifier to match the fabricated multilayer actuators is also designed, fabricated and test. Experiment results show that the micro-displacement amplifier can obtain a peak to peak displacement of 160 um under the quasi-static condition.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"154 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133553344","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364487
Bo Zhang, Jiangong Yu, Xiaoming Zhang
Maradudin firstly proposed Laguerre orthogonal polynomial to solve the acoustic waves in homogeneous semi-infinite wedges in 1972. However, the approach can deal with the multilayered structures only when there is no significant change for the material properties of two adjacent layers. In order to overcome the drawbacks of the conventional polynomial approach, this paper proposed an improved orthogonal polynomial method to investigate the propagation of Love waves in a half-space. Comparison with the available reference results confirmed the correctness of the improved polynomial approach. The dispersion curves of Love waves in a multilayer elastic half-space are illustrated.
{"title":"Love waves in multilayered elastic half-space: An improved orthogonal polynomials method","authors":"Bo Zhang, Jiangong Yu, Xiaoming Zhang","doi":"10.1109/SPAWDA.2015.7364487","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364487","url":null,"abstract":"Maradudin firstly proposed Laguerre orthogonal polynomial to solve the acoustic waves in homogeneous semi-infinite wedges in 1972. However, the approach can deal with the multilayered structures only when there is no significant change for the material properties of two adjacent layers. In order to overcome the drawbacks of the conventional polynomial approach, this paper proposed an improved orthogonal polynomial method to investigate the propagation of Love waves in a half-space. Comparison with the available reference results confirmed the correctness of the improved polynomial approach. The dispersion curves of Love waves in a multilayer elastic half-space are illustrated.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134325718","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364493
Min Li, C. Gao
Based on the complex potential method, the two-dimensional problem of an elliptic piezoelectric plate is studied when the plate is compressed by a pair of concentrated forces along the y direction. Firstly, the complex potentials inside the plate are expressed in form of Faber series with unknown coefficients, and they are solved by using boundary conditions. Numerical examples show that the maximum longitudinal stress along the x axis exist at the center of the plate or on the boundary when the loads are applied in the y axis, and the magnitude is determined by the ratio of long to short half axes of the piezoelectric plate.
{"title":"A two-dimensional study of an elliptic piezoelectric plate compressed diametrically","authors":"Min Li, C. Gao","doi":"10.1109/SPAWDA.2015.7364493","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364493","url":null,"abstract":"Based on the complex potential method, the two-dimensional problem of an elliptic piezoelectric plate is studied when the plate is compressed by a pair of concentrated forces along the y direction. Firstly, the complex potentials inside the plate are expressed in form of Faber series with unknown coefficients, and they are solved by using boundary conditions. Numerical examples show that the maximum longitudinal stress along the x axis exist at the center of the plate or on the boundary when the loads are applied in the y axis, and the magnitude is determined by the ratio of long to short half axes of the piezoelectric plate.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126663533","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364469
Yu-ying Wang, Longbiao He, Haijiang Zhu, Ping Yang
The calibration of piezoelectric acoustic emission sensors mainly includes two methods, reciprocity method and surface pulse method. The former uses the principle of electro-acoustic reciprocity of piezoelectric sensors, and the latter needs a reference capacitance or laser system for displacement or velocity measurement. Prior studies have indicated that the two methods had some consistency, but some scholars still questioned the reciprocity calibration of piezoelectric acoustic emission sensors. In this paper the equivalent and real reciprocity coefficient were calculated and compared to test their consistency. Experimental system was established to test and verify the results. The test results showed that the reciprocity and surface pulse method had good agreement.
{"title":"Consistency of surface pulse and reciprocity calibration of piezoelectric AE sensors","authors":"Yu-ying Wang, Longbiao He, Haijiang Zhu, Ping Yang","doi":"10.1109/SPAWDA.2015.7364469","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364469","url":null,"abstract":"The calibration of piezoelectric acoustic emission sensors mainly includes two methods, reciprocity method and surface pulse method. The former uses the principle of electro-acoustic reciprocity of piezoelectric sensors, and the latter needs a reference capacitance or laser system for displacement or velocity measurement. Prior studies have indicated that the two methods had some consistency, but some scholars still questioned the reciprocity calibration of piezoelectric acoustic emission sensors. In this paper the equivalent and real reciprocity coefficient were calculated and compared to test their consistency. Experimental system was established to test and verify the results. The test results showed that the reciprocity and surface pulse method had good agreement.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126863925","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 : 2015-10-01DOI: 10.1109/SPAWDA.2015.7364516
Yahui Tian, Hong-lang Li, Yabing Ke, Ce Yuan, S. He
This paper has studied the influence of filling fraction on the band gaps of two-dimensional (2-D) piezoelectric phononic crystals (PnCs) in radio frequency (RF). The 2-D piezoelectric PnCs consists of tungsten (W) stubs on the finite slab of 128°YXLiNbO3 substrate. With Bloch periodic theorem, the single cell model was built using the three-dimensional (3-D) finite element method (FEM). Based on the 3-D FEM model, band structures of the 2-D piezoelectric PnCs were calculated with different filling fractions. Results show that with the increase of the filling fraction, amount of the band gaps increase from one to two, the width of the first band gap becomes narrower and the second band gap become wider firstly and then become narrower, but all these widths become convergent. These results are useful for the applications of the 2-D piezoelectric PnCs in the RF devices as broadband filters and multi-channels filters.
{"title":"Influence of filling fraction on the band gaps of two-dimensional piezoelectric phononic crystals in radio frequency","authors":"Yahui Tian, Hong-lang Li, Yabing Ke, Ce Yuan, S. He","doi":"10.1109/SPAWDA.2015.7364516","DOIUrl":"https://doi.org/10.1109/SPAWDA.2015.7364516","url":null,"abstract":"This paper has studied the influence of filling fraction on the band gaps of two-dimensional (2-D) piezoelectric phononic crystals (PnCs) in radio frequency (RF). The 2-D piezoelectric PnCs consists of tungsten (W) stubs on the finite slab of 128°YXLiNbO3 substrate. With Bloch periodic theorem, the single cell model was built using the three-dimensional (3-D) finite element method (FEM). Based on the 3-D FEM model, band structures of the 2-D piezoelectric PnCs were calculated with different filling fractions. Results show that with the increase of the filling fraction, amount of the band gaps increase from one to two, the width of the first band gap becomes narrower and the second band gap become wider firstly and then become narrower, but all these widths become convergent. These results are useful for the applications of the 2-D piezoelectric PnCs in the RF devices as broadband filters and multi-channels filters.","PeriodicalId":205914,"journal":{"name":"2015 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124854107","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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