Papers by Author: Long Tu Li

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Authors: Xiang Cheng Chu, Long Ma, Long Tu Li, Zhi Lun Gui
Abstract: A micro piezoelectric motor with a disk-pivot structure is presented. Different from conventional wobble-type piezoelectric motor using piezoelectric rod or cylinder, piezoelectric disc is used to excite wobble modes and metal cylinder stator is used to amplify the transverse displacement, metal rod rotor is actuated to rotate. The outer diameter of the actuator is 14mm. In this paper, the performances of the motor are characterized, where a high rotation speed and a high toque are obtained. The property of start-up period movement of the motor was studied by a high-speed camera. The toque of the motor was calculated by the property of the start-up movement.
Authors: Ye Ji, Xiang Cheng Chu, Long Tu Li, Zhi Lun Gui
Abstract: A novel rotary piezoelectric micro-motor (φ8mm×10mm) is proposed in this paper. Different from the conventional traveling wave ultrasonic motor using piezoelectric ceramic ring, four multilayer co-firing piezoelectric ceramic bulks (2mm×2mm×3mm) are used to generate vibration in the ring type stator. The layout and electric signals applied to the piezoelectric ceramic bulks are designed for the purpose of generating elliptical trajectories on the surface of the stator. The working mode of the prototype motor is simulated by the finite element method, and also measured by the Doppler Laser Vibrometer. The experimental results are in good agreement with simulation, which verifies the effectiveness of the finite element model. The prototype motor is driven at the low voltage of 12V under the frequency of 64.91 KHz.
Authors: Bao Wei Wang, Xiang Cheng Chua, Long Tu Li
Abstract: This paper presents a valve-less micropump which is actuated by a piezoelectric ceramic chip. We employ a microelectromechanical system process for the silicon substrate and anodic bonding for assembly of the Pyrex glass and silicon wafer. The reciprocating type micropump contains two nozzle/diffuser elements and a silicon membrane with an embedded piezoelectric ceramic actuator.
Authors: Xiang Cheng Chu, Ren Bo Yan, Li Yan, Long Tu Li
Authors: Xiao Bing Hu, Long Tu Li, Xiang Cheng Chu, Zhi Lun Gui
Authors: Xiang Cheng Chu, Ren Bo Yan, Wen Gong, Long Tu Li
Abstract: The dynamic behavior of a vibration converter of an ultrasonic motor is described using finite element method. Tetrahedral finite elements with three dimensions are formulated with the effects of piezoelectric coupling. And the solution of the coupled electroelastic equations of dynamic motion is presented. The simulated response of the vibration converter is calculated, and shows excellent consistency with experimental results, which proved that finite element modeling is a good approach to optimize piezoelectric apparatus design. A gradual optimized method is employed to ascertain the most compatible structure.
Authors: Jun Jie Hao, Xiao Hui Wang, Jian Ling Zhao, Long Tu Li
Abstract: Textured bismuth titanate ceramics were successfully produced by spark plasma sintering, using plate-like Bi4Ti3O12 particles prepared by a molten salt method. The microstructure and electric properties of the samples were investigated. The results show that the textured Bi4Ti3O12 ceramics electric property is anisotropic in different direction, and spark plasma sintering is an effective sintering technology to get textured dense Bi4Ti3O12 ceramics at a low temperature.
Authors: Yong Li Wang, Long Tu Li, Jian Quan Qi, Zhi Lun Gui
Authors: Mao Wang, Zhen Xing Yue, Ji Zhou, Long Tu Li, Zhi Lun Gui
Authors: Hong Jie Zhao, Ji Zhou, Zhi Lun Gui, Long Tu Li
Abstract: The effects of Bi-substitution on the complex impedance spectra of yttrium iron garnet (YIG) were studied in this paper. The polycrystalline yttrium iron garnet Y2BiFe5O12 (YIG: Bi) and Y3Fe5O12 (YIG) samples were prepared by solid-reaction method. The complex impedance spectra were measured in the frequency range from 1 KHz to 100MHz at several temperatures between 210oC and 500oC. The complex impedance sample shows that the YIG: Bi can be represented by double Cole-Cole semicircles, and the YIG can be represented by a single Cole semicircle. The physical structure of the specimen was visualized as comprising of small resistance grains separated by large resistance grain boundaries in accordance with the impedance spectra observations. The electrical processes in the sample were modeled in the form of an electrical equivalent circuit made up of a series combination of two parallel RC circuits attributed to grains and grain boundaries. The temperature dependence of bulk resistance indicated an evidence of Arrhenius-type thermally activated process, showing a close to linear variation up to a temperature of 740 K.
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