硅基压电悬臂梁式微麦克风的设计与优化

设计了一种硅基PZT压电悬臂梁式微麦克风.这种微麦克风采用压电多层膜悬臂梁作为声压感受器件,采用有限元耦合场分析的方法对压电复合膜悬臂梁进行了有限元分析和模拟,研究了压电复合多层膜悬臂梁的结构参数与力学性能的关系,分析了影响微麦克风机电性能的多种因素,给出了优化的器件结构和工艺流程.     

基于原子力显微镜的悬臂梁微尖端器件应用新进展

在分析原子力显微镜工作原理的基础上,详细介绍了各种基于原子力显微镜的悬臂梁微尖端器件的应用进展,并展望了悬臂梁微尖端器件的发展前景。     

硅基压电悬臂梁式微麦克风的设计与优化

设计了一种硅基PZT压电悬臂梁式微麦克风。这种微麦克风采用压电多层膜悬臂梁作为声压感受器件,采用有限元耦合场分析的方法对压电复合膜悬臂梁进行了有限元分析和模拟,研究了压电复合多层膜悬臂梁的结构参数与力学性能的关系,分析了影响微麦克风机电性能的多种因素,给出了优化的器件结构和工艺流程。     

悬臂梁微尖端器件的制备与应用研究进展

随着扫描隧道显微镜(SPM)家族的成熟,悬臂梁微尖端MEMS器件的广泛应用前景也逐渐清晰.对悬臂梁微尖端MEMS器件的种类、微尖端制作方法以及现今的研究应用方向进行了论述,最后指出了悬臂梁微尖端MEMS器件向着大规模阵列化发展的方向.     

微型电磁继电器的制作和仿真分析

介绍了一种基于MEMS技术的微型电磁继电器的制作过程和仿真分析.这种微继电器的大小约是4mm×4mm×0.5mm,主要采用普通的微加工技术来完成全部制作工艺.与传统继电器相比,这种继电器采用平面线圈来代替螺线管线圈,有利于MEMS工艺,并且提出了一种双支撑的悬臂梁结构做为活动电极,具有较高的灵敏性和稳定性.另外,还进行了一些有关线圈通过激励电流后对活动电极产生电磁力的理论计算和仿真分析,利用这些结果可以对这种电磁继电器的结构和参数进一步优化.     

微型电磁继电器的制作和仿真分析

介绍了一种基于MEMS技术的微型电磁继电器的制作过程和仿真分析.这种微继电器的大小约是4mm×4mm×0.5mm,主要采用普通的微加工技术来完成全部制作工艺.与传统继电器相比,这种继电器采用平面线圈来代替螺线管线圈,有利于MEMS工艺,并且提出了一种双支撑的悬臂梁结构做为活动电极,具有较高的灵敏性和稳定性.另外,还进行了一些有关线圈通过激励电流后对活动电极产生电磁力的理论计算和仿真分析,利用这些结果可以对这种电磁继电器的结构和参数进一步优化.     

硅基压电悬臂梁式微麦克风的设计与优化

设计了一种硅基PZT压电悬臂梁式微麦克风。这种微麦克风采用压电多层膜悬臂梁作为声压感受器件，采用有限元耦合场分析的方法对压电复合膜悬臂梁进行了有限元分析和模拟，研究了压电复合多层膜悬臂梁的结构参数与力学性能的关系，分析了影响微麦克风机电性能的多种因素，给出了优化的器件结构和工艺流程。     

水平静电驱动式多晶3C-SiC折叠悬臂梁谐振器微结构

介绍了一种微机械叉指静电驱动折叠悬臂梁谐振器的设计和制作方法.将Rayleigh分析法和有限元分析法结合起来分析调整器件尺寸和材料参数对器件性能的影响.制作了三种不同悬臂梁宽度的微机械横向谐振器件,经实验检测它们的谐振频率分别为64.5,147.2,255.5kHz,与模拟结果符合得很好.该结果显示由于具有很高的杨式模量,利用多晶3C-SiC材料体系制作的谐振器件能够具有更高的谐振频率.     

水平静电驱动式多晶3C-SiC折叠悬臂梁谐振器微结构

介绍了一种微机械叉指静电驱动折叠悬臂梁谐振器的设计和制作方法.将Rayleigh分析法和有限元分析法结合起来分析调整器件尺寸和材料参数对器件性能的影响.制作了三种不同悬臂梁宽度的微机械横向谐振器件,经实验检测它们的谐振频率分别为64.5,147.2,255.5kHz,与模拟结果符合得很好.该结果显示由于具有很高的杨式模量,利用多晶3C-SiC材料体系制作的谐振器件能够具有更高的谐振频率.     

扭梁悬臂梁支撑的扭摆式MEMS永磁双稳态机构

在进行理论分析证实可行性和模拟仿真优化参数后,利用非硅表面微加工方法中的牺牲层工艺制备了一种扭梁悬臂梁支撑的扭摆式MEMS永磁双稳态机构.该双稳态结构尺寸为1.9mm×1.6mm×0.03mm,通过永磁力实现稳态姿态无功耗保持,通过对其单侧触点施加纵向驱动力使之达到30μm的纵向驱动位移,可以实现机构的双稳态姿态切换,可以通过控制永磁体磁片、悬臂梁和扭梁的尺寸来灵活调控稳态切换所需的驱动力矩.此双稳态机构可与电磁驱动、电热驱动和静电驱动等类型的微驱动器联用构成永磁双稳态MEMS微继电器.     

Fabrication of low-stress low-stiffness leveraged cantilever beam for bistable mechanism

This paper presents the fabrication and application of a leveraged cantilever beam with low-stress and low-stiffness. This cantilever beam is overhanged with two free ends and suspended in air by the supporting torsion flexures fixed at its middle. The teeterboard-typed cantilever features a low-stiffness with 1.63 N/m, and a low-stress with ±6.27 MPa. The cantilever beam was prepared by a laminated photoresist sacrificial layer process (LPSLP), that is, a multilayered photoresist film for supporting the suspended cantilever beams. In this work, two main problems related to microfabrication process were discussed. One is the control of residual stress in permalloy cantilever with varying the contents of additive saccharin to minimize the deformation of the free end of the beams. The other is an improved wet release method to avoid the adhesion or stiction of the all metal microstructures. The proposed leveraged cantilever beam has a potential application on the bistable switching mechanism in single-pole-double-through (SPDT) latching relay fields. Switching between two stable states of the microbeam mechanism was successfully validated with WYKO NT1100 optical profiling system.     

Design and implementation of a bistable microcantilever actuator for magnetostatic latching relay

This paper presents the design, fabrication, and implementation of a microcantilever actuator with magnetostatic latching for performing low power bistable relay applications. This unique bistable feature consists of a low-stiffness torsion/cantilever beam system with circular-shaped support and a permanent magnet for holding the closed state with a permalloy soft magnetic circuit. The special circular support is designed to enhance the stiffness of the overhang beams. First, mechanical modeling of the leveraged torsion/cantilever beams was performed by Castigliano’s theorem so as to deduce the spring stiffness of system. Then the device has been prepared by a laminated photoresist sacrificial layer process (LPSLP). Finally, mechanical performance was characterized by atomic force microscopy (AFM), combined with finite element simulation using ANSYS™ package and analysis model as well. Switching between two stable states of the microactuator was successfully validated with WYKO NT1100 optical profiling system.     

Analog Nanoelectromechanical Relay With Tunable Transconductance

We show by simulation that a three-terminal nanoelectromechanical (NEM) relay combined with a feedback resistor provides a tunable transconductance $G_{m}$ over an adjustable input-voltage range. The $G_{m}$ arises from the modulation of the drain tunneling current by the gate voltage and does not require mechanical contact between the cantilever tip and the drain electrode. The introduced analog relay featuring current–voltage characteristics that are very similar to those of electronic transistors paves the path for purely electromechanical systems, where sensors and actuators can be integrated with NEM analog circuits and emerging NEM logic and memory devices.      

Two-way中继系统协作节点选择及功率分配策略

为了提高Two-way中继系统总速率,该文提出了一种Two-way AF中继系统的双向中继选择(BRS)策略,该策略通过联合考虑中继节点处的接收信噪比和中继节点到目的节点间的信道增益,实现了最优中继选择。进一步,在最优中继基础上提出了Two-way中继系统两种优化功率分配策略:(1)基于凸优化的功率分配策略(OPA-CO);(2)基于信道增益差异的优化功率分配策略(OPA-DCG)。方案(1)提出了总功率受限的条件下最大化Two-way中继系统总速率的优化模型;方案(2)通过考虑链路之间信道增益的不同,提出了一种速率增量最大化的数学优化模型,为降低求解凸优化模型的复杂度,采用一种迭代功率分配算法求解上述优化模型。仿真结果证明两种策略均能提高系统总速率。     

阵列式微机械悬臂梁的研制及其特性分析

在一个芯片上设计了六组不同规格的矩形压阻悬臂梁.采用ANSYS有限元分析系统对微压阻悬臂梁进行应力分析,并对压阻悬臂梁的噪声、灵敏度以及最小可探测位移进行了研究.选用多晶硅为压阻材料,以硅微机械加工技术为基础,完成了阵列式压阻悬臂梁的制备.通过测量器件的噪声和灵敏度,计算出在6V偏压和10 0 0Hz测量带宽下,多晶硅悬臂梁的最小可探测位移为1nm .     

On Determining the Reliability of Protective Relay Systems

This paper lays the ground work for the statistical determination of the reliability of protective relay systems found in electric power systems. The reliability problem has two conflicting requirements: 1) failure to operate in the presence of a fault and 2) unnecessary operation when a fault occurs that the relay or relay system was set to ignore. It is not often treated in reliability literature.     

Chemisorption sensing and analysis using silicon cantilever sensor based on n-type metal-oxide-semiconductor transistor

This paper presents a silicon cantilever sensor based on n-type metal-oxide-semiconductor transistor for chemical sensing and analysis using the chemisorption-induced surface stress sensing principle. The cantilever is along the 〈1 0 0〉 crystal orientation of the (1 0 0) silicon, and the transistor channel is parallel to as well as located at the rear part of the cantilever to obtain high stress sensitivity. The gold film deposited on the bottom surfaces of cantilevers is chemically functionalized with a self-assembled monolayer of 4-mercaptobenzoic acid via the Au-SH covalent bonding. The vapor phase chemical sensing experiments with acetone, ethanol, nitroethane and water vapor as targets are performed. The observed response differentiation implies that the molecular interaction mechanisms between different chemical molecules are different.     

一种“回”字形多方向压电能量收集方法

该文介绍了一种“回”字形的多方向微型压电振动能量收集装置,其由尺寸为34 mm×2 mm×1 mm的正方形边框包围,内部结构包含4个非对称的组合悬臂梁,主悬臂梁固定于边框内壁,并与z 方向垂直,次悬臂梁连接在主悬臂梁的末端质量块上。首先建立基础激励条件下组合悬臂梁振动系统的动力学模型。然后,通过有限元仿真分析对比了不同刚度和质量对位移幅值的影响,验证了组合悬臂梁系统的振动特性,并确定了最佳结构参数值:当主、次悬臂梁厚度均为0.3 mm,主、次质量块的最佳惯性质量分别为619.32 g、342.3 g。经仿真计算得到z 方向可输出电能功率为3.138 5 mW,x、y 方向可输出功率均为0.720 5 mW。最后搭建微型能量收集器实验平台,在实际测试中z 方向的输出功率为2.85 mW,x、y 方向的输出功率均为0.57 mW。     

Efficient Beamforming by SLNR Maximization for Dual-Hop Relay Assisted MIMO Network

Relay beamforming is a key signal processing technique to mitigate interference in single and multiuser multiple input and multiple output (MIMO) wireless communication networks. In MIMO relay networks interference cancellation is an essential task of the study to get optimal network capacity. In this paper, the problem of interference resulted from leakage signal from desired signal for intended antenna, which causing interference to other antennas of the same user with multiple antennas is tackled. The criterion of signal to leakage plus noise ratio (SLNR) maximization is considered to design a vector by vector relay downlink precoding based on Fukunaga Koontz transform. This can control the interference among multiple antennas and maximize SLNR. However, matched filter beamforming is utilized at the relay receiving side that can increase output signal to noise ratio at the relay node. The channel state information of both the channel between source to relay and relay to destination is assumed at the relay node. The effectiveness of the proposed technique is studied and compared with conventional relay precoding techniques. Simulation is carried out in MATLAB environment using ideal channel conditions. This study demonstrates that, the proposed scheme for relay assisted MIMO networks can improve overall system performance in terms of ergodic capacity.     

基于微场镜阵列的红外光场中继成像系统

光场成像是一种通过采集光场信息和重聚焦计算而成像的方法。由于微透镜型光场相机的结构限制,为实现光学系统与探测器的耦合,一般采用改造探测器的方法,但不适用于红外光场相机。为此,提出了微场镜阵列结合中继透镜的新型结构。这种新型结构通过中继透镜对中间像面1:1成像,通过微场镜阵列改善中继透镜产生的渐晕。采用倾斜刃边法计算系统的调制传递函数曲线,对比直接耦合、中继透镜耦合以及新型结构耦合三种结构的像质。根据不同的重聚焦面,新型耦合结构在奈奎斯特频率下的曲线值相比于中继透镜耦合结构提升5%~240%,接近直接耦合结构。新型结构可在实现耦合的同时,避免系统像质的大幅度下降,可在红外光场相机中起到重要作用。