压电膜片的优化设计及在微泵中的应用

压电驱动是微机械系统(MEMS)微执行器最有发展前途的驱动方式之一。该文采用ANSYS有限元软件对压电膜片结构参数和在微执行器上的装配方法进行了优化设计,得到PZT/Si,PZT/Cu压电膜片结构的优化数据,将其应用于有阀微泵的研制。经测试,微泵压电驱动效果与仿真结果一致,微泵背压可达836 Pa,流量达1.4 mL/min。     

一种医用微型同心压电薄膜泵

设计开发了一种结构新颖，制作工艺简单，成本低，综合性能高的烈性药物输注用压电薄膜微型泵，介绍了微泵的结构设计、工作原理和性能测试。微泵具有在出口和入口两个方向上抵抗冲击载荷的能力和互锁的功能，适合于对外界环境要求苛刻的烈性药物输注。微泵不论液体还是气体为工作介质都具有良好的流量特性和较高的可靠性。同心双向阀结构克服了传统的单向阀并联结构两阀间易连通的缺点。高分子聚合物材料和特殊的加工装配工艺使得微泵即使在小批量单件生产的情况下成本依然低廉。因此，该种微泵更加接近实用化，具有广阔的应用前景。     

一种大功率宽带毫米波波导滤波器

介绍了一种毫米波频段的大功率波导滤波器，综合出其四阶耦合矩阵，采用矩形波导膜片方案仿真设计，得到了中心插损小于0.3dB 的宽带波导滤波器。并对该滤波器在常压和真空环境下所能承受的功率进行了分析，试验结果表明该滤波器具有尺寸小，便于加工调试，可用于星载大功率环境的优点。     

毫米波E面膜片滤波器的加工误差研究

E面膜片滤波器由于结构简单、高Q值、滤波特性好、设计精度高、易于批量生产等优点,在毫米波雷达系统中得到广泛应用.文中对E面膜片滤波器进行了理论分析,利用误差合成法以及数据模拟仿真,研究了Ka波段E面膜片滤波器中,膜片厚度、膜片安装、膜片长度在不同加工误差下,对滤波器系统性能S参数的影响,为其加工制造提供理论指导.     

一种基于惯性动量作用的微压电泵

提出一种新的微压电泵工作机理,采用环形流道式泵腔与两个无运动件阀,形成双级惯性动量作用机制。通过减小腔内回流比例、增大正反方向流阻差,提高泵液效率与输出泵压、减小输出脉动。仿真结果表明该工作机理是可行的。     

一种220 GHz滤波器的设计

基于电感膜片矩形波导滤波器设计方法和加工流程,设计了一个220 GHz带通滤波器。滤波器采用玻璃片—硅片—陶瓷片结构,由硅片形成电感膜片结构,玻璃片、陶瓷片键合在硅片上形成闭合的谐振腔,采用集成电路的制作工艺,在加工前分析了工艺特性,优化了滤波器尺寸,避免工艺对滤波器关键尺寸的影响。采用信号源、功率计进行测试,测试结果表明,滤波器在220 GHz具有通带特性,带内损耗约为7 dB。     

锥管坡面腔底无阀压电泵流场分析

针对坡面腔底无阀压电泵流量小的问题,提出并研制了一种锥管坡面腔底无阀压电泵,即将锥管与坡面腔底组合式新结构作为其无移动部件阀。首先,提出了锥管坡面腔底无阀压电泵结构并分析其工作原理,对泵流量进行理论分析;同时,运用Fluent软件的动网格功能对其内部流场模拟分析。仿真结果表明,该泵具有单向流动特性,在泵腔内部产生漩涡利于液体的混合搅拌。最后,加工制作了锥管坡面腔底无阀压电泵样机,并对该泵进行了流量试验。试验结果表明,驱动电压峰值为250V,频率为5 Hz时,最大流量为25.9mL/min,证明了锥管坡面腔底无阀压电泵的有效性。     

微型腔中的光学过程

微型腔中的光学过程现在正在进行各种凝聚态物质系统的光学微型共振腔研究，其尺寸在０·１～１０ｖｉｎ之间。理想情况下，人们可在全反射壁一侧的１立方半波长体积中隔离出一个单模光场。液滴、聚合物球和带电介质镜的半导体法布里一用罗微型腔都是微型共振腔的实例，用...     

基于PVDF压电膜片的光声探测器制备及应用

非共振光声红外气体检测系统因其结构简单,成本低和检测灵敏度高的特点,具有较好的应用前景。该文提出了以聚偏氟乙烯(PVDF)压电膜片为微压敏感元件的非共振光声探测器,利用ANSYS对压电膜片进行了有限元分析,设计制备了双膜片结构微压敏感元件,其中PVDF压电膜片厚度为20 μm,尺寸为10 mm×5 mm。设计了包含吸收腔和补偿腔的双腔室结构,并完成了光声探测器的封装。将光声探测器应用于非分光红外(NDIR)气体检测系统,探测器的输出信号与CO2气体浓度有较好的线性关系,最低理论检测浓度约为29×10-6。     

基于PVDF压电膜片的光声探测器制备及应用

非共振光声红外气体检测系统因其结构简单,成本低和检测灵敏度高的特点,具有较好的应用前景。该文提出了以聚偏氟乙烯(PVDF)压电膜片为微压敏感元件的非共振光声探测器,利用ANSYS对压电膜片进行了有限元分析,设计制备了双膜片结构微压敏感元件,其中PVDF压电膜片厚度为20μm,尺寸为10mm×5mm。设计了包含吸收腔和补偿腔的双腔室结构,并完成了光声探测器的封装。将光声探测器应用于非分光红外(NDIR)气体检测系统,探测器的输出信号与CO_2气体浓度有较好的线性关系,最低理论检测浓度约为29×10~(-6)。     

Recrystallization and intermetallic formation in Au/Al and Au/Zn bimetallic films

Bimetallic thin films are of interest for use in microelectromechanical systems (MEMS) for the fabrication of sensors and actuators. The coefficient of thermal expansion (CTE) mismatch between the two metal films of the bimetallic structure can be used to attain the desired level of deflection or actuation in the MEMS device. Gold/aluminum and gold/zinc films have desirable properties for use in bimetallic films because of their differences in CTE. The stress-temperature behavior of these bimetal configurations has been studied. The effect of deposition technique and recrystallization of the metal films on the total stress and strain of the bimetallic films has been investigated. It has been shown that the formation of intermetallic compounds between the metal layers changes the mechanical properties of composite films. The intermetallic compounds are often undesirable because of their uncontrolled composition and poor mechanical properties. The degree of formation of the intermetallic compounds in the gold/aluminum bimetallic films can be reduced by use of a diffusion barrier between the two metals. It is shown that aluminum oxide is an effective diffusion barrier, and it can be easily fabricated. Stress-strain measurements and chemical depth profiling of the bimetallic films with the diffusion barrier have been used to quantify the reduction in the formation of the intermetallic compounds.     

MEMS微针的最新研究进展

介绍了MEMS微针技术在微针制备工艺、力学和流体性能模拟以及透皮给药方面研究的近况。描述了硅、金属和聚合物材料的微针制备工艺,分析了这些材料在MEMS微针应用上的优缺点。比如硅微针制备工艺成熟但是硅的质地太脆;金属微针机械强度高却不易载药;聚合物微针易于批量化复制但是机械强度差。进一步阐述了微针研究取得的进展,总结了微针技术发展需要解决的关键问题。微针制备工艺已经日趋成熟,微针将朝着可复制化、批量化方向发展,微针经皮给药将逐渐从动物实验转移到人体实验,以实现微针研究的最终目的——临床给药。     

多层梁机电耦合系统的等效电路宏模型

实现MEMS器件系统级模拟的关键是建立其宏模型。由单层梁构成的机电耦合系统的等效电路宏模型 ,已做过深入的研究 ,但实际的MEMS器件通常都是多层的 .本文提出了一种基于力 电压 (F V)类比的、适用于由多层梁构成的机电耦合系统的等效电路宏模型 ,该模型可进行小信号时域和频域分析 ,能为多层梁机电耦合系统的设计带来很大的方便。模拟结果表明 ,该模型具有较高的精度     

基于MEMS技术的微型气相色谱柱的研究进展

微型气相色谱柱是基于MEMS技术的微型分析化学器件,主要用于混合化学组分的分离,采用MEMS技术制作的微 型气相色谱柱在体积上得到了极大的缩小,便于集成到便携式设备中,其次,微型器件带来更小的热容量,因而能在更小的功 耗下获得更快的升温速率,从而加快了分析速度,进而改进了器件的整体性能.针对MEMS微型气相色谱柱的研究...     

基于双金属膜的光纤MEMS温度传感器的设计

提出了一种新型结构的温度传感器,该传感器基于Fabry-Perot干涉和双金属效应.采用MEMS技术制作出线性度好、精度高的光纤MEMS温度传感器.阐述了传感器的工作原理,研究了传感器的力学模型,确定了温度敏感膜材料,用有限元软件ANSYS验证了模型的合理性.模拟了法珀腔的腔长对温度传感器性能的影响,为传感器的加工制作提供了理论依据.该设计可为以硅为基底的压力传感器提供一种温度补偿方法.     

A 0.3-mW/Ch 1.25 V Piezo-Resistance Digital ROIC for Liquid-Dispensing MEMS

A low-power multichannel CMOS digital read-out IC (ROIC) for differential piezo-resistive sensing is presented as part of the positioning system of a liquid dispensing MEMS. New very low-voltage and single-battery compatible CMOS circuits are proposed for digital gain tuning, pre-amplification, and integrating A/D conversion. Overall low-power consumption is achieved by operating the key devices in subthreshold in order to prevent from heating the fluidic MEMS. A complete quad-channel ROIC has been integrated in 0.35- $mu{hbox {m}}$ CMOS 2-polySi 4-metal technology. The reported experimental results agree with the electrical simulations.      

Development of an automatic implanted drug infusion system for themanagement of cardiac arrhythmias

Conventional management of cardiac arrythmias relies on oral drug therapy which minimizes recurrence of the arrhythmia, but risks unpleasant side effects and even long-term toxicity. The authors propose acute management instead, from an implanted drug pump which automatically senses the onset of arrhythmia, delivers a pharmacokinetically-based infusion to terminate the episode, and discontinues drug delivery until the next occurrence. A bedside system consisting of a personal computer and conventional intravenous pump has been developed and tested in five dogs and 24 patients during a catheter electrophysiologic study. After detection of the arrhythmia plasma levels of the antiarrhythmia drug rose immediately to the therapeutic range and were subsequently well-controlled for 30 to 60 minutes. In all five dogs and in seven of the eight patients in whom atrial fibrillation was induced during the study, conversion to normal rhythm occurred within fifteen minutes     

Using neural networks as a fault detection mechanism in MEMS devices

Micro Electro Mechanical Systems (MEMS) were first proposed about 20 years ago. Today, many different kinds have been fabricated and are used in industry, space and scientific fields. The scale and relative size of analog integrated circuits and non-electrical parts are becoming smaller. As a result, the need for automatic test of MEMS is a critical requirement in MEMS fabrication and maintenance. The rapid progress in the design of these systems has not, however, been accompanied by a similar progress in fault classification technologies. MEMS are naturally very non-linear, complex and multi-domain and systems are fabricated near to each other. A large number of faults of different types may occur. This paper presents a combination of a Competitive Neural Network (CNN) and a Robust Heteroscedastic Probabilistic Neural Network (RHPNN) for fault detection in MEMS. The RHPNN has previously been proposed for analog fault detection. Finding the optimum kernel number in the second layer is a drawback of the RHPNN method. In this paper we have used a CNN for finding the optimum kernel number automatically. In addition, as the simulation results show, the correct fault detection percentage is increased in comparison with the RHPNN alone.     

Flexible Transient Bioelectronic System Enables Multifunctional Active-Controlled Drug Delivery

On-demand drug delivery systems (DDSs) have tremendous promise for clinical in vivo personalized drug delivery. However, the current DDSs are monofunctional and unable to meet the individualized needs of patients. Herein, a biodegradable multifunctional active-controlled drug delivery system (ADDS) is reported. The device can be implanted in various tissues with valves controlled by the deactivation of magnesium (Mg) for rapid drug release from drug reservoirs and long-term drug delivery with the biodegradation of the ADDS. Multiple chambers are constructed by designing a structure with tandem Mg valves and aligning them in the z-axis direction, allowing the system to deliver drugs in a pulsatile or sequential manner. The biodegradability of the entire system minimizes the potential side effects of the ADDS. The application of the device for drug delivery in rats confirmed its ability to perform pulsatile delivery in vivo. The excellent biocompatibility and dual timeline drug delivery capability of this system are demonstrated with cellular and in vitro vascular bioreactors. This multifunctional ADDS will play an important role in precise drug delivery in the treatment of chronic diseases and diseases with complications.     

三束飞秒激光辐照下铜膜内电子非平衡热输运

首先采用有限元法数值计算了铜膜内的电子温度和晶格温度分布变化,揭示了铜膜内电子非平衡热输运时间随飞秒激光光束参量的变化情况。仿真结果表明,铜膜内的电子非平衡热输运时间会随着泵浦光束数量及脉冲能量密度的增加而增加,并且使用三束飞秒泵浦激光作用时,电子非平衡热输运时间比单脉冲作用时的电子非平衡热输运时间增加了3倍。其次使用三束飞秒激光泵浦的泵浦-探测实验系统进行验证。实验结果表明:通过用具有一定延时的三束飞秒泵浦激光作用铜膜时,铜膜表面的瞬态反射率出现三次突变,使电子非平衡热输运时间得到极大延长,从而大幅度消除激光加工热障,并提高加工的质量、精度和效率。