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There are 23 papers published in subject: > since this site started. |
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1. The radially sandwiched piezoelectric composite ultrasonic transducers | |||
LIN Shuyu,XU Jie | |||
Physics 26 November 2015 | |||
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Abstract:The radially composite transducer is composed of an inner metal ring and an outer radially polarized piezoelectric ceramic ring. The radial vibration of the piezoelectric and metal rings is analyzed and their electro-mechanical equivalent circuits are obtained. Based on the mechanical boundary conditions between the piezoelectric and metal rings, the three-port electromechanical equivalent circuit for the radially composite ultrasonic transducer is obtained and the frequency equation is given. The theoretical relationship between the resonance/anti-resonance frequency and the effective electro-mechanical coupling coefficient with the geometrical dimensions of the composite transducer is analyzed. The radial vibration of the composite transducer is simulated by using Finite Element Method. Some radially composite piezoelectric ultrasonic transducers are designed and manufactured; their resonance/anti-resonance frequencies are measured. It is shown that the analytical resonance/anti-resonance frequencies are in good agreement with the numerically simulated and experimental results. | |||
TO cite this article:LIN Shuyu,XU Jie. The radially sandwiched piezoelectric composite ultrasonic transducers[OL].[26 November 2015] http://en.paper.edu.cn/en_releasepaper/content/4665254 |
2. Research on an Annular Piezoelectric Ceramic Composite Transformer in Radial Vibration | |||
XU Jie,LIN Shuyu | |||
Physics 26 November 2015 | |||
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Abstract:A new structure of annular piezoelectric ceramic composite transformer in radial vibration is proposed and its characteristics are researched. The new piezoelectric transformer consists of two concentric piezoelectric ceramic rings and a metal ring in the radial direction. By deducing the electro-mechanical equivalent circuit of the piezoelectric composite transformer, the equations of resonance/ anti-resonance frequency, voltage gain and efficiency are obtained. The dependences of the electromechanical characteristics (resonance frequency, effective electro-mechanical coupling coefficient, voltage gain and efficiency) on geometrical dimension of the metal ring, the mechanical loss and load impedance are analyzed. To verify the analytical theory, the frequency and voltage gain of piezoelectric transformers are measured. It is shown that the experimental results are in good agreement with the analytical results. | |||
TO cite this article:XU Jie,LIN Shuyu. Research on an Annular Piezoelectric Ceramic Composite Transformer in Radial Vibration[OL].[26 November 2015] http://en.paper.edu.cn/en_releasepaper/content/4665251 |
3. Study on the multi-mode pumping of Terahertz parametric oscillators | |||
LI Jiaqi,WANG Yuye,XU Degang,LI Zhongxiao,YAN Chao,LIU Pengxiang,YAO Jianquan | |||
Physics 29 May 2014 | |||
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Abstract:We experimentally studied the influence of multi-transverse-mode pumping on the output characteristics of terahertz parametric oscillators (TPO). It was shown in our experiments that the beam quality of pumping beam affected the output power significantly. The THz output energy varied from 172nJ to 17nJ when M2 value of pump beam varied from 4.21 to 11.1 under the same pumping energy of 120mJ/pulse. The experiment results were explained by the gain enhancement effect in stimulated Raman emission under multi-mode pumping. | |||
TO cite this article:LI Jiaqi,WANG Yuye,XU Degang, et al. Study on the multi-mode pumping of Terahertz parametric oscillators[OL].[29 May 2014] http://en.paper.edu.cn/en_releasepaper/content/4598745 |
4. A Robust Sound Sources Near-field Localization method used Worst Case Concept | |||
SHI Jie,YANG Desen,SHI Shengguo | |||
Physics 06 April 2014 | |||
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Abstract:Minimum variance distortionless response (MVDR) focused beamformer based on vector sensor array is widely used in the area of the noise source high-resolution localization and identification. However, when an arbitrary unknown signal steering vector mismatch occurs or the training sample size is small, the performance of MVDR focused beamformer will be severely degraded. In this paper, we develop a new approach, which is based on the worst-case concept, to improve the robustness of the original method. It is shown that the proposed algorithm improves its robustness by imposing the array response constraint on the uncertainty set of the steering vector, and can be reformulated in a convex form as the so called second order cone program (SOCP), and then solved efficiently using the well established optimization tool, Sedumi. Theory analysis and computer simulations show better performance of our robust beamformer as compared with the existing methods: it can achieve a greater dynamic range,sharper focused peak,and lower back-ground noise level.The results in this paper demonstrate our proposed method can be applied in the underwater noise source high-resolution localization and identification. | |||
TO cite this article:SHI Jie,YANG Desen,SHI Shengguo. A Robust Sound Sources Near-field Localization method used Worst Case Concept[OL].[ 6 April 2014] http://en.paper.edu.cn/en_releasepaper/content/4592519 |
5. Local Resonance Broadband Gap in a Homogeneous Plate with Periodic Truncated Cones | |||
Jiujiu Chen,Hongbo Zhang,Xu Han | |||
Physics 01 March 2013 | |||
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Abstract:Periodic elastic structures, also known as phononic crystals (PCs), have shown many exceptional elastic-wave characteristics. In particular, complete phononic band gap (PBG) in the structure that forbids the propagation of acoustic waves in certain frequency range has demonstrated the possibility of manipulating the acoustic energy flows in diverse ways. The complete PBGs have been found for various forms of elastic waves in distinct PC structures, such as bulk waves in bulk PCs, surface waves in semi-infinite PCs, and Lamb waves in PC plates. In this paper, the band structures in a homogeneous plate with periodic truncated cones for the square lattice based on finite element method (FEM) are investigated. The radius of the truncated cone is gradually reduced from the lower base to the upper base. Compared to the classical stubbed phononic plates, a considerable enlargement of the bandwidth by a factor of 2.04 is obtained by varying the semiangle of the truncated cone, while the truncated cone's weight is only 65.19% of that of the cylinder of the stubbed case. Moreover the relative bandwidth is also enlarged by a factor of 1.68. We show that this band gap enlargement is due to the acoustic waves of different wavelengths is localized at the different parts of the truncated cone. These characteristics of elastic or acoustic waves suggest potential applications in aerospace. | |||
TO cite this article:Jiujiu Chen,Hongbo Zhang,Xu Han. Local Resonance Broadband Gap in a Homogeneous Plate with Periodic Truncated Cones[OL].[ 1 March 2013] http://en.paper.edu.cn/en_releasepaper/content/4525413 |
6. Asymmetric Lamb Wave Propagation in graded grating phononic crystal slabs | |||
Chen Jiujiu ,Hongbo Zhang,Xu Han | |||
Physics 31 January 2013 | |||
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Abstract:The invention of electric diodes, which are the first devices to enable the rectification of current flux, marks the emergency of modern electronics, leads to worldwide revolutions in many aspects, and deeply changes our daily lives. Compared with electricity, the acoustic wave is an important form of classical wave that is more ubiquitous in nature and has much longer research history. In this paper, the unidirectional transmission of Lamb wave in low-frequency domains is realized by graded grating phononic crystal slabs. The transmission spectra of Lamb waves in this system can be obtained by the eigenmode matching theory (EMMT) method and the finite element (FE) method (COMSOL MULTIPHSICS). Significant differences between the acoustic transmission along two opposite directions can be observed. This exotic phenomenon stems from the threshold frequency of the fundamental antisymmetric Lamb mode conversion to the fundamental symmetric Lamb mode is different at the different locations of the acoustic diode. This realization should be potentially significant in helping design chip-scale directional phononic devices. | |||
TO cite this article:Chen Jiujiu ,Hongbo Zhang,Xu Han. Asymmetric Lamb Wave Propagation in graded grating phononic crystal slabs[OL].[31 January 2013] http://en.paper.edu.cn/en_releasepaper/content/4519637 |
7. Influences of electrode arrangements on flexural vibrations of piezoelectric ceramic tubes | |||
Zhang Hui,Zhang Shuyi,Fan Li | |||
Physics 05 March 2012 | |||
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Abstract:Flexural vibration characteristics of piezoelectric ceramic tubes in acoustic actuators are studied by an electro-mechanical coupling Timoshenko beam model. In the model, the piezoelectric effects are considered, and effects of the different electrode arrangements on Young's modulus are investigated. Additionally, the particular attentions are devoted to effects of the mass loads on flexural resonance frequencies of the piezoelectric ceramic tubes. The predicted resonance frequencies of the ceramic tubes are sensitive to the mechanical parameters of the tubes. The bipolar and unipolar electrode arrangements have little effects on the flexural vibrations of piezoelectric ceramic tubes in acoustic actuatorsn. | |||
TO cite this article:Zhang Hui,Zhang Shuyi,Fan Li. Influences of electrode arrangements on flexural vibrations of piezoelectric ceramic tubes[OL].[ 5 March 2012] http://en.paper.edu.cn/en_releasepaper/content/4468267 |
8. Acoustic waves propagating through 12-fold quasi-periodic sonic crystals | |||
LU Minghui,LIU Xiaokang,NI Xu | |||
Physics 12 January 2012 | |||
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Abstract:Propagation of acoustic waves through 12-fold quasi-periodic sonic crystals (QSCs) has been studied by the multiple scattering method. Flat QSC lenses can focus acoustic waves at frequencies on both sides of the first gap of transmission spectrum. We have found this focusing imaging result from local multiple scattering in QSC, which means the modulation of density and modulus among short range plays a key role in controlling acoustic waves propagating in QSC. The focusing imaging was found to have the far-field-imaging and abaxial characteristics. In some case, there are two focusing imaging in the system due to the self-similarity of quasi-crystals. In addition, localized modes have been investigated in this paper. All the characteristics of acoustic wave propagating through QSCs stated above originate from the 12-fold symmetry of QSCs. | |||
TO cite this article:LU Minghui,LIU Xiaokang,NI Xu. Acoustic waves propagating through 12-fold quasi-periodic sonic crystals[OL].[12 January 2012] http://en.paper.edu.cn/en_releasepaper/content/4461769 |
9. Individualized HRTF matching and compression for virtual sound | |||
Sun Qing,Miao Hua,Ma Qingyu | |||
Physics 12 July 2011 | |||
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Abstract:Players in audio-only games can only control the game process based on the orientation information of the sound source in three dimensional virtual sound space and so real-time processing with high accuracy is needed in virtual sound reproduction. In this paper, the individualized HRTF matching and compression method is proposed and validated through signal processing progress of the CIPIC and MIT data using the PCA method, based on the basic principle of three dimensional virtual sounds. Little error between the original and the compress-reconstruct HRTF data prove that the proposed method can be applied in real-time processing system with less storage and simplified computational complexity to enhance the reproduction speed and accuracy. The favorable result prpvide the feasibility of the proposed method in practical application of virtual sound. | |||
TO cite this article:Sun Qing,Miao Hua,Ma Qingyu. Individualized HRTF matching and compression for virtual sound[OL].[12 July 2011] http://en.paper.edu.cn/en_releasepaper/content/4435296 |
10. The correlation between acoustic cavitation involved in ultrasound-mediated DNA transfection in vitro | |||
TU Juan,QIU Yuanyuan,ZHANG Yanli,CUI Weicheng,ZHANG Dong,CHEN Weizhong | |||
Physics 30 December 2010 | |||
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Abstract:Background: It has been shown that the efficiency of gene/drug delivery can be enhanced under ultrasound (US) ex-posure with the presence of US contrast agent microbubbles, due to the acoustic cavitation-induced sonopration. However, obstacles still remain to achieve controllable sonopration outcome. The general hypotheses guiding present studies were that inertial cavitation (IC) activities accumulated during US exposure could be quantified as IC dose (ICD) based on passive cavitation detection (PCD), and the assessment of sonopration outcome should be correlated with ICD measurements. Methods: In current work, MCF-7 cells mixed with PEI: DNA complex were exposed to 1-MHz US pulses with 20-cycle pulse length and varied acoustic peak negative pressure (P?; 0 (sham), 0.3, 0.75, 1.4, 2.2 or 3.0 MPa), total treatment time (0, 5, 10, 20, 40 or 60 s), and pulse-repetition-frequency (PRF; 0, 20, 100, 250, 500, or 1000 Hz). Four series experiments were conducted: (1) the IC activities were detected using a PCD system and quantified as ICD; (2) the DNA transfection efficiency was evaluated with flow cytometry; (3) the cell viability was examined by PI dying then measured using flow cytometry; and (4) scan electron microscopy was used to inves-tigate the sonopration effects on the cell membrane. Results: (1) the ICD generated during US-exposure could be af-fected by US parameters (e.g., P?, total treatment time, and PRF); (2) the pooled data analyses demonstrated that DNA transfection efficiency initially increased linearly with the increasing ICD, then it tended to saturate instead of trying to achieve a maximum value while the ICD kept going up; and (3) the measured ICD, sonopration pore size, and cell viability exhibited high correlation among each other. All the results indicated that IC activity should play an important role in the US-mediated DNA transfection through sonopration, and ICD could be used as an effective tool to monitor and control the US-mediated gene/drug delivery effect. | |||
TO cite this article:TU Juan,QIU Yuanyuan,ZHANG Yanli, et al. The correlation between acoustic cavitation involved in ultrasound-mediated DNA transfection in vitro[OL].[30 December 2010] http://en.paper.edu.cn/en_releasepaper/content/4402666 |
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