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Formulas for the transfer functions and electric resistance for transducers that consist of an arbitrary number of active (piezoelectric) and passive layers are obtained. Parallel and series electrical connections of layers are considered. Formulas for reducing any active layer to a passive one are obtained. On the basis of the analysis of the obtained expressions and presented calculation results, recommendations for the practical use of the considered transducers are expounded. The obtained data allow the development of transducers with appreciably improved characteristics in comparison to the case where only one active element is used. The proposed new calculation method makes it possible to substantially simplify the determination of formulas for an arbitrary number of layers. The formulas for the main functions of a transducer concern multiple three-sided transducers, on one side of which certain conditions for their electrical connection are imposed. The transfer functions for the reception mode with respect to the voltage at the working surface of the transducer are obtained. The proposed calculation method can be also applied to other types of transducers. 相似文献
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为了在保持电机精度的同时获得较大作动行程,提出了一种以叠层压电陶瓷作为激励振动源的压电直线电机。分析了电机的工作原理,推导了电机驱动足在工作时的运动轨迹。设计安装了电机样机,并对其定子进行了测试。最后,在两种激发条件下实验研究了电机的整机性能。结果表明:单组叠层压电陶瓷激励时,该样机定子驱动头在接触面法向和切向同时具有振动分量,并能够在阶跃和连续两种不同激励方式下实现单向大行程直线运动。以锯齿波激励时可实现步进运动,激励频率为20Hz时步距为0.1μm;以两路相位差π/2的正弦波激励时,可在1.5kHz到5.8kHz的激励频率区间输出稳定连续的直线运动,其运动速度随激励频率的升高而增大,在峰-峰值110V(50V偏置)的正弦电压激励下其推力可达4.8N。该电机具有高位置分辨率和宽频率响应,可以在两种工作模式下分别稳定地实现直线步进和大行程连续运行。 相似文献
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In this study, a disk-shaped piezoelectric transformer was fabricated using lead-free (K,Na)NbO(3)-based ceramics with high mechanical quality factor. The transformer can operate in the fundamental or the third radial vibration mode. The transformer is poled along the thickness direction. The top surface is covered by ring/dot silver electrodes separated by an annular gap which serve as the input and output parts of the transformer, respectively. The bottom surface, fully covered with a silver electrode, is grounded as a common electrode. The dimensions of the top ring/dot electrodes are designed such that the third radial vibration mode can be strongly excited. The electrical properties of the transformer with diameter of 34.2 mm and thickness of 1.9 mm were measured. For a temperature rise of 35 degrees C, the transformer has a maximum output power of 12 W. With the matching load, its maximum efficiency is >95%, and maximum voltage gains are 6.5 and 3.9 for the fundamental and the third radial vibration modes, respectively. It has potential to be used in power supply units and other electronic circuits. 相似文献
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Guo M Lam KH Wang S Kwok KW Chan HL Zhao XZ 《The Review of scientific instruments》2007,78(12):125103
In this study, a modified disk-shaped multiple-output piezoelectric transformer operated at the fundamental radial vibration mode has been presented. A derived equivalent circuit for the multioutput piezoelectric transformer was used to analyze the performance. Two piezoelectric transformers, a symmetrically electroded piezoelectric transformer with dual outputs and an asymmetrically electroded piezoelectric transformer with triple outputs, were fabricated with lead zirconate titanate piezoelectric ceramics. The characteristics of the two piezoelectric transformers were investigated experimentally. The piezoelectric transformer with multiple outputs has potential to be used in power supply units and other electronic circuits. 相似文献
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We report an enhanced magnetoelectric (ME) effect in a heterostructure consisting of a long-type, longitudinally-longitudinally polarized 0.71Pb(Mg(1∕3)Nb(2∕3))O(3)-0.29PbTiO(3) (PMN-PT) piezoelectric single-crystal transformer with its input part sandwiched between two longitudinally magnetized Tb(0.3)Dy(0.7)Fe(1.92) (Terfenol-D) magnetostrictive alloy bars. The observed ME effect has two independent operational modes: namely, ME sensing mode and ME transduction mode. The ME sensing mode features a large ME voltage coefficient (α(V)) of ~0.32 V∕Oe over a flat frequency range of 1-50 kHz, while the ME transduction mode possesses two colossal resonance α(V) of 7.6 and 7.9 V∕Oe, corresponding to the first and second longitudinal resonances, at 56.2 and 127.9 kHz, respectively. This enhanced dual-mode ME effect not only enables the application potential of the heterostructure, but also advances the technology of power-free ME sensors and transducers. 相似文献
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Acoustic emission (AE) sensors have been fabricated using both soft- and hard-type lead-free (Na0.5K0.5)NbO3-based ceramics. The acoustic and electromechanical properties of the ceramics have been determined using the resonance technique. The lead-free AE sensors were calibrated using a laser source and compared to a commercial sensor. A lead zirconate titanate (PZT) 5H ceramics AE sensor has also been fabricated and calibrated for comparison. It was found that the sensitivity of lead-free AE sensors is comparable to that of the lead-based PZT sensor. To evaluate the sensors for potential application, they have been used in the detection of AE in an impact test. The lead-free sensors can reproduce AE signals accurately without giving artifacts and have potential use in commercial AE systems. 相似文献
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In this study, a Rosen-type Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) single crystal piezoelectric transformer is presented. First, we simulate the operation of this transformer using the finite element method and ANSYS. By adjusting the dimensions of the piezoelectric transformer, a maximum voltage step-up ratio of 138 can be obtained at a frequency of 33.8 kHz when the output part is open. Second, we fabricate a transformer with the size of 20 mm length, 4 mm width, and 1 mm thickness to examine the simulation results. It is found that this transformer exhibits a maximum voltage step-up ratio of 134 at 37 kHz, with the efficiency over 95% when driving a liquid crystal display backlight, which shows good consistency with the numerical simulation results. Besides, we investigate the electrical properties under different frequencies and load resistances. When the input voltage increases, a maximum output power of 1 W is obtained with the temperature rise less than 10 degrees C. 相似文献
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介绍了近几年无铅钎料的应用研究和发展情况以及与无铅钎料有关的立法。为国内电子材料行业无铅钎料的研究和发展提出建议。 相似文献
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压电发电工作于低频时所收集的能量与其等效压电常数和等效电压常数的乘积成正比。为了研究Cymbal型压电发电装置的等效压电常数,建立了Cymbal型压电发电装置的三维有限元分析模型,并分析得出了等效压电常数计算公式;详细地分析了Cymbal型发电装置中金属帽的材料和厚度、金属腔底端直径和顶端直径、金属腔高度、压电陶瓷片厚度等因素对等效压电常数的影响,并给出了等效压电常数的优化准则。试验结果表明,经优化后可获得的等效压电常数大约相当于压电陶瓷本身的60倍。 相似文献
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提出了无铅、有铅过渡阶段的主要问题——无铅、有铅器件的兼容性和无铅器件、有铅焊料的兼容性问题,以及无铅、有铅混装的2种有效解决方法:1)无铅、有铅兼容性的回流温度测试曲线的优化,既满足无铅器件的焊接,又满足有铅器件的焊接;2)无铅、有铅植球转换,将无铅器件转换为有铅器件,并分别对2种方法进行了相关试验,验证了2种解决方法的可靠性。 相似文献
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研制了不需要外部附加微位移与微力传感器、采用自感知方法来获取压电微夹钳的钳指位移与夹持力的压电自感知微夹钳。根据压电陶瓷晶片在驱动电压与外力作用下发生变形会在其表面产生电荷的思想,提出了基于积分电荷的钳指位移与夹持力的自感知方法;基于Jan G.Smits的压电悬臂梁弯曲变形理论,给出了钳指位移与夹持力的自感知表达式,即用钳指上压电陶瓷晶片表面的电荷来表达钳指位移与夹持力。设计了获取晶片表面电荷的积分电路,给出了其平衡条件为晶片电容与其绝缘电阻之积同积分电容与反馈电阻之积相等。自感知验证实验结果表明:修正后在31.59μm最大钳指位移范围内的自感知位移最大偏差为0.78μm;在35.91mN最大钳指夹持力范围内的自感知夹持力的最大偏差为0.24mN。实验结果验证了所提自感知方法是有效的。 相似文献
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Conley R Liu C Qian J Kewish CM Macrander AT Yan H Kang HC Maser J Stephenson GB 《The Review of scientific instruments》2008,79(5):053104
A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures. 相似文献
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