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为达到在脉动气流激励下抑制风洞模型振动的目的,该文提出了基于压电陶瓷作动器神经网络模型的风洞模型主动振动控制方法,并进行了实验研究。首先,分析了风洞模型系统振动特性,建立了内嵌式压电陶瓷作动器的主动振动控制系统,通过模型质心加速度推算出压电陶瓷作动器期望输出抑振力。然后,建立了压电陶瓷作动器期望输出抑振力 激励电压的神经网络模型,并根据该模型设计了一种实时解算加速度为激励电压的控制方法。最后,通过地面试验对控制方法的有效性进行验证。实验结果表明,该控制方法具有良好的实时性和鲁棒性,在锤击试验中,振动加速度衰减时间相比于压电方程线性控制时减小了54.46%,系统阻尼比增大了1.58倍,取得了良好的控制效果。 相似文献
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<正> 有资料介绍,检查晶振或陶瓷滤波器时,用万用表欧姆档测量,如果测量结果为无穷大,则说明晶振或陶瓷滤波器是好的。笔者认为这种测量结果还不能说明晶振或陶瓷滤器是好是坏,因为即使晶振或陶瓷滤波器坏了,如果引脚在内部断了,测量结果也是无穷大。 晶振和陶瓷滤波器都是在压电材料两面涂上银层,再在银层上焊上电极引线作引脚,再经封装而制成的。这两种元件就像是一个小电容器,用测量小电容器的方法来判断晶振和陶瓷滤波器的好坏就比较可靠。具体的测量方法是:把万用表拨到10k挡,用两只NPN型三极管(如3DG6、 相似文献
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超声换能器是微电子封装技术的核心执行元件,为解决传统一维纵振超声换能器键合效率低、键合面不均匀及键合点不牢靠等问题,采用ANSYS仿真软件建立换能器有限元模型进行模态分析及谐响应分析,设计了一种可同时实现轴向纵振、水平弯振及竖直俯仰振动的40 kHz多向复合夹心压电式超声换能器。其中,压电部分由整圆环和可单独激励的1/4圆环陶瓷片组成。利用阻抗分析仪实物测试,得到换能器纵振、弯振及俯仰振动的阻抗 频率特性曲线。结果表明,测试值与仿真值基本一致,且结构性能参数均符合键合要求,验证了该结构的合理性。 相似文献
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模拟电路的计算机辅助设计是电子类本科生的必备专业技能,本文采用LTSPICE软件对RCC结构手机充电器电路进行设计仿真,通过分析元器件模型及参数选取、电路启振和稳定工作过程,以及外部环境和元器件参数对电路性能的影响,实现了电路的计算机辅助设计和调试。该实验既能使学生理解简易的RCC开关电源的工作原理,又能掌握电路计算机仿真的方法。非常适合于模拟电路类课程实验。 相似文献
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N/A 《激光与光电子学进展》1974,11(7):1
依据化学泵浦反应和碰撞弛豫过程,评论了各种化学激光器的特性。概述了业巳报导过的反应产物分子的各振动能级的化学反应速率之值,讨论了反应产物被激励的原理。根据碰撞动力学也扼要地解释了振-转、平动、振-振弛豫的机理。HF激射系统的计算机模拟是通过含有泵浦反应、振-转、平动、振-振弛豫和受激跃迁的动力学的耦合微分方程进行的。 相似文献
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A. V. Zakharov 《Journal of Communications Technology and Electronics》2013,58(3):265-272
Stripline bandpass combline filters designed on high-permittivity ceramic materials are analyzed. In order to form coupling between codirectional quarter-wave resonators, they are connected in the regions of their short-circuited ends by a stripline conductor. Features of the characteristics of such filters are revealed and compared with the parameters of other ceramic microwave filters. Experimental characteristics of a stripline filter designed on a ceramics with permittivity ?r = 38 are presented. The experimental results are in good agreement with results of computer simulation. 相似文献
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In Japan, there has been considerable activity in the research and manufacturing of quartz crystal filters, ceramic filters and mechanical filters. This paper reviews some of these contributions. An emphasis is placed on filters actually used. First multiple-mode resonators are reviewed; this concept having had profound effects on all types of filters. Quartz-crystal filters as well as other crystal filters are discussed. Then follow reviews on ceramic and mechanical filters. 相似文献
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Ching-Wen Tang Che-Wei Shen Ping-Ju Hsieh 《Microwave Theory and Techniques》2009,57(1):172-179
With the assistance of modified coupled inductors, novel multilayered bandpass filters are developed in this paper. Two or three transmission zeros appear on both sides of the passband skirt easily by incorporating the proposed structures. In order to fabricate compact multilayered bandpass filters, the low-temperature co-fired ceramic technology is also employed. In addition, the equivalent circuits of the modified coupled inductors are also proposed. Consequently, the measured results of the fabricated bandpass filters agree well with the responses of the full-wave electromagnetic design. 相似文献
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Delhote N. Baillargeat D. Verdeyme S. Delage C. Chaput C. 《Microwave Theory and Techniques》2007,55(3):548-554
Three-dimensional (3-D) ceramic stereolithography has been developed and used to manufacture RF devices using periodic structures. To our knowledge, it is the first time that zirconia and high-performance Ba3ZnTa2O9 ceramics are used with that process to manufacture high unloaded quality factor resonant structures and bandpass filters working in the Ka-band. A theoretical study on the performances of periodic arrangements of high-permittivity structures has been carried out and has led to the manufacture of a high unloaded quality factor cavity and narrow three-pole filter (1% bandwidth) measured at a working frequency of 33 GHz 相似文献
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100MHz陶瓷声表面波窄带滤波器研究 总被引:1,自引:1,他引:0
给出了在Nd,In,Mn改性PbTiO3压电陶瓷基片上,采用三次谐波,设计和制作100MHz的声表面波窄带滤波器的研究结果。 相似文献
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《Microwave Theory and Techniques》2009,57(7):1760-1766
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