The Experts below are selected from a list of 342501 Experts worldwide ranked by ideXlab platform
Zheng Zhong - One of the best experts on this subject based on the ideXlab platform.
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A study of pressure-shear vertical wave propagation in periodically layered fluid and piezoelectric structure
Journal of Applied Physics, 2013Co-Authors: J. Zhao, Zheng ZhongAbstract:In this paper, the pressure (P) and shear vertical (SV) wave propagation in the periodically layered fluid and piezoelectric structure are theoretically studied. A single piezoelectric layer is first analyzed for three scenarios: Piezoelectricity-ignored, electrically open, or electrically closed. It is observed that both the Lamb wave dispersion curves and the transmission coefficients are affected by Piezoelectricity and electrical boundary conditions under any incident angle. From the analyses of the periodically layered structure, it is further found that the Piezoelectricity and the electrical boundary conditions have influence on band gaps for a given incident angle.
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Theoretical study of shear horizontal wave propagation in periodically layered piezoelectric structure
Journal of Applied Physics, 2012Co-Authors: J. Zhao, Zheng ZhongAbstract:In this paper, the propagation of the shear horizontal wave (SH-wave) in the single piezoelectric layer and periodically layered piezoelectric structure is studied. Both the dispersion equation and transmission coefficients are derived to reveal the wave behavior of the corresponding structures when the Piezoelectricity is ignored or the electrical circuit is open and closed. The zero-order mode of the Piezoelectricity-ignored single plate is not dispersive and every higher order mode is dispersive with a cut-off frequency. Same features are found for the electrically open and closed cases except that the zero-order mode of the latter case is no more non-dispersive. The pass bands of the Piezoelectricity-ignored periodically layered structure appear when the normalized frequency is an even integer under the normal incidence, and new stop bands will appear from the pass bands as the incident angle increases. The same features are observed for the band gaps of the electrically open and closed cases except t...
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theoretical study of shear horizontal wave propagation in periodically layered piezoelectric structure
Journal of Applied Physics, 2012Co-Authors: J. Zhao, Yongdong Pan, Zheng ZhongAbstract:In this paper, the propagation of the shear horizontal wave (SH-wave) in the single piezoelectric layer and periodically layered piezoelectric structure is studied. Both the dispersion equation and transmission coefficients are derived to reveal the wave behavior of the corresponding structures when the Piezoelectricity is ignored or the electrical circuit is open and closed. The zero-order mode of the Piezoelectricity-ignored single plate is not dispersive and every higher order mode is dispersive with a cut-off frequency. Same features are found for the electrically open and closed cases except that the zero-order mode of the latter case is no more non-dispersive. The pass bands of the Piezoelectricity-ignored periodically layered structure appear when the normalized frequency is an even integer under the normal incidence, and new stop bands will appear from the pass bands as the incident angle increases. The same features are observed for the band gaps of the electrically open and closed cases except that the zero-order mode of the latter case is dispersive. The stop bands of the periodic structure will change in a cycle as the geometric ratio increases from zero to one.
J. Zhao - One of the best experts on this subject based on the ideXlab platform.
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A study of pressure-shear vertical wave propagation in periodically layered fluid and piezoelectric structure
Journal of Applied Physics, 2013Co-Authors: J. Zhao, Zheng ZhongAbstract:In this paper, the pressure (P) and shear vertical (SV) wave propagation in the periodically layered fluid and piezoelectric structure are theoretically studied. A single piezoelectric layer is first analyzed for three scenarios: Piezoelectricity-ignored, electrically open, or electrically closed. It is observed that both the Lamb wave dispersion curves and the transmission coefficients are affected by Piezoelectricity and electrical boundary conditions under any incident angle. From the analyses of the periodically layered structure, it is further found that the Piezoelectricity and the electrical boundary conditions have influence on band gaps for a given incident angle.
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Theoretical study of shear horizontal wave propagation in periodically layered piezoelectric structure
Journal of Applied Physics, 2012Co-Authors: J. Zhao, Zheng ZhongAbstract:In this paper, the propagation of the shear horizontal wave (SH-wave) in the single piezoelectric layer and periodically layered piezoelectric structure is studied. Both the dispersion equation and transmission coefficients are derived to reveal the wave behavior of the corresponding structures when the Piezoelectricity is ignored or the electrical circuit is open and closed. The zero-order mode of the Piezoelectricity-ignored single plate is not dispersive and every higher order mode is dispersive with a cut-off frequency. Same features are found for the electrically open and closed cases except that the zero-order mode of the latter case is no more non-dispersive. The pass bands of the Piezoelectricity-ignored periodically layered structure appear when the normalized frequency is an even integer under the normal incidence, and new stop bands will appear from the pass bands as the incident angle increases. The same features are observed for the band gaps of the electrically open and closed cases except t...
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theoretical study of shear horizontal wave propagation in periodically layered piezoelectric structure
Journal of Applied Physics, 2012Co-Authors: J. Zhao, Yongdong Pan, Zheng ZhongAbstract:In this paper, the propagation of the shear horizontal wave (SH-wave) in the single piezoelectric layer and periodically layered piezoelectric structure is studied. Both the dispersion equation and transmission coefficients are derived to reveal the wave behavior of the corresponding structures when the Piezoelectricity is ignored or the electrical circuit is open and closed. The zero-order mode of the Piezoelectricity-ignored single plate is not dispersive and every higher order mode is dispersive with a cut-off frequency. Same features are found for the electrically open and closed cases except that the zero-order mode of the latter case is no more non-dispersive. The pass bands of the Piezoelectricity-ignored periodically layered structure appear when the normalized frequency is an even integer under the normal incidence, and new stop bands will appear from the pass bands as the incident angle increases. The same features are observed for the band gaps of the electrically open and closed cases except that the zero-order mode of the latter case is dispersive. The stop bands of the periodic structure will change in a cycle as the geometric ratio increases from zero to one.
Manabu Kishimoto - One of the best experts on this subject based on the ideXlab platform.
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13C n.m.r. studies on the microstructure of poly(vinylidene cyanide/vinyl benzoate) and poly(vinylidene cyanide/styrene)
Polymer, 2003Co-Authors: Yoshio Inoue, Akio Kashiwazaki, Yoichi Maruyama, Yong Sung Jo, Riichiro Chujo, Manabu KishimotoAbstract:Abstract The microstructure of vinylidene cyanide-vinyl benzoate and vinylidene cyanide-styrene copolymers, both of which were prepared by radical copolymerization, were studied by 125 MHz 13 C n.m.r. spectroscopy. The former shows high Piezoelectricity, while the latter has low Piezoelectricity. It was found that the compositional sequence distribution and tacticity of both copolymers were not largely different from each other, namely, both were highly alternating copolymers with a non-stereoregular structure. Possible origins of Piezoelectricity were suggested for vinylidene cyanide copolymers.
Xiaobing Ren - One of the best experts on this subject based on the ideXlab platform.
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a structural phase boundary due to oxygen octahedral tilt untilt transition in bi0 5na0 5tio3 based piezoelectric ceramics
Journal of Applied Physics, 2020Co-Authors: Shuai Ren, Kang Yan, Xiaobing Ren, Fangfang Wang, Kongjun ZhuAbstract:The investigation of fine structural evolutions around the morphotropic phase boundary (MPB) is important to understand the origin of the high Piezoelectricity in ferroelectric ceramics. Here, we report a new phase boundary associated with oxygen octahedral tilt–untilt transition by exploring average and local structural evolutions in the vicinity of MPB in Bi0.5Na0.5TiO3–PbTiO3 (BNT–PT) ceramics. It is found that the local structural change of the oxygen octahedral tilt–untilt transition is decoupled with the average structural change of the rhombohedral-to-tetragonal phase transition at MPB in BNT–PT. The slight octahedral tilting distortion at MPB is responsible for the large high-field-induced electrostrain and small low-field-induced Piezoelectricity in BNT–PT. The crucial difference of MPB between BNT–PT and the classical piezoelectric Pb(Zr,Ti)O3 is discussed from their local structural evolutions of octahedral tilting to the performance changes at MPB. It helps us to figure out the origin of large high-field-induced electrostrain but small Piezoelectricity in BNT-based ceramics.
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crucial role of octahedral untilting r3m p4mm morphotropic phase boundary in highly piezoelectric perovskite oxide
Acta Materialia, 2017Co-Authors: Shuai Ren, Minxia Fang, Kang Yan, Xiaobing RenAbstract:Abstract Large Piezoelectricity is usually found at morphotropic phase boundary (MPB), a composition-induced phase boundary between two ferroelectric phases. However, only a small fraction of MPBs (e.g., in PZT and PMN-PT) show large Piezoelectricity. It remains a long-standing puzzle why not all MPBs yield large Piezoelectricity. Here, by a comparative study of two MPB systems of BaZr 0.2 Ti 0.8 O 3 -PbTiO 3 (BZT-PT) and Bi 0.5 Na 0.5 TiO 3 -PbTiO 3 (BNT-PT), we find that the symmetry relation between the two ferroelectric phases at MPB plays a crucial role in piezoelectric activity. BZT-PT ceramic, having an R 3 m / P 4 mm MPB, exhibits strong Piezoelectricity of d 33 = 500 pC/N, whereas BNT-PT ceramic, having an R 3 c / P 4 mm MPB, exhibits much weaker Piezoelectricity of d 33 = 150 pC/N. The sharp difference between the two types of R/T MPBs is shown to arise from a significant difference in free energy barrier associated with oxygen octahedral tilting at MPB. An oxygen octahedral tilting/untilting transition at R 3 c / P 4 mm MPB leads to a high free energy barrier and results in low piezoelectric activity, whereas R 3 m / P 4 mm MPB with octahedral untilting produces large Piezoelectricity due to low free energy barrier at such MPB. This feature show quite general in most of present MPBs systems and may become a dependable guideline for designing highly piezoelectric Pb-free materials.
Kang Yan - One of the best experts on this subject based on the ideXlab platform.
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a structural phase boundary due to oxygen octahedral tilt untilt transition in bi0 5na0 5tio3 based piezoelectric ceramics
Journal of Applied Physics, 2020Co-Authors: Shuai Ren, Kang Yan, Xiaobing Ren, Fangfang Wang, Kongjun ZhuAbstract:The investigation of fine structural evolutions around the morphotropic phase boundary (MPB) is important to understand the origin of the high Piezoelectricity in ferroelectric ceramics. Here, we report a new phase boundary associated with oxygen octahedral tilt–untilt transition by exploring average and local structural evolutions in the vicinity of MPB in Bi0.5Na0.5TiO3–PbTiO3 (BNT–PT) ceramics. It is found that the local structural change of the oxygen octahedral tilt–untilt transition is decoupled with the average structural change of the rhombohedral-to-tetragonal phase transition at MPB in BNT–PT. The slight octahedral tilting distortion at MPB is responsible for the large high-field-induced electrostrain and small low-field-induced Piezoelectricity in BNT–PT. The crucial difference of MPB between BNT–PT and the classical piezoelectric Pb(Zr,Ti)O3 is discussed from their local structural evolutions of octahedral tilting to the performance changes at MPB. It helps us to figure out the origin of large high-field-induced electrostrain but small Piezoelectricity in BNT-based ceramics.
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crucial role of octahedral untilting r3m p4mm morphotropic phase boundary in highly piezoelectric perovskite oxide
Acta Materialia, 2017Co-Authors: Shuai Ren, Minxia Fang, Kang Yan, Xiaobing RenAbstract:Abstract Large Piezoelectricity is usually found at morphotropic phase boundary (MPB), a composition-induced phase boundary between two ferroelectric phases. However, only a small fraction of MPBs (e.g., in PZT and PMN-PT) show large Piezoelectricity. It remains a long-standing puzzle why not all MPBs yield large Piezoelectricity. Here, by a comparative study of two MPB systems of BaZr 0.2 Ti 0.8 O 3 -PbTiO 3 (BZT-PT) and Bi 0.5 Na 0.5 TiO 3 -PbTiO 3 (BNT-PT), we find that the symmetry relation between the two ferroelectric phases at MPB plays a crucial role in piezoelectric activity. BZT-PT ceramic, having an R 3 m / P 4 mm MPB, exhibits strong Piezoelectricity of d 33 = 500 pC/N, whereas BNT-PT ceramic, having an R 3 c / P 4 mm MPB, exhibits much weaker Piezoelectricity of d 33 = 150 pC/N. The sharp difference between the two types of R/T MPBs is shown to arise from a significant difference in free energy barrier associated with oxygen octahedral tilting at MPB. An oxygen octahedral tilting/untilting transition at R 3 c / P 4 mm MPB leads to a high free energy barrier and results in low piezoelectric activity, whereas R 3 m / P 4 mm MPB with octahedral untilting produces large Piezoelectricity due to low free energy barrier at such MPB. This feature show quite general in most of present MPBs systems and may become a dependable guideline for designing highly piezoelectric Pb-free materials.
