Toward flexible and antibacterial piezoresistive porous devices for wound dressing and motion detectors

Wearable and antibacterial porous devices are promising new multifunctional materials with a wide range of applications in wound dressing and human motion monitoring systems. The deposition of carbon nanotubes and polypyrrole coating on conventional elastomers (polyurethane) is a single‐step procedure that results in a low‐cost, highly conductive, and flexible piezoresistive material with pressure sensitivity of 0.09 kPa⁻¹, Gauge Factor of −10.3, high stability in response to different mechanical efforts and reversible netlike microcracks formation under moderate stretching deformation. The resulting porous material provides direct detection of simple movements from human joints (knee, finger, and elbow) and intrinsic antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1063–1072     

MOS力敏运算放大器

利用MOSFET的压阻效应,本文提出了力敏运算放大器的概念、基本原理和设计思想.作为其应用之一,研制出一种新型集成压力传感器——集成MOS力敏运放压力传感器.这种压力传感器具有很高的压力响应灵敏度,可望在诸多领域有广泛应用.     

三轴压阻微加速度计的结构力学分析

为了提高三轴加速度计机械精度和加工过程中硅片的一致性,设计了基于SOI的单质量块四边八梁结构的三轴加速度计。通过连接扩散在梁上的压敏电阻构成得惠斯通电桥检测三个方向的加速度信号。电桥设计为开环形式,并给出三个方向的电桥输出。结合材料力学和振动力学中的相关理论,建立了结构的数学模型,并对其进行了系统的力学分析,从而得出结构参数对加速度计的一阶固有频率、灵敏度等性能的影响。利用有限元ANSYS仿真软件对结构模型进行了静态和模态分析,验证了力学分析的正确性。最后设计了八张版图及一套可行的工艺流程并加工出加速度计裸片。该微加速度计可同时检测三维加速度矢量,且电桥和结构的设计均较好的抑制了横向效应。     

基于STM8S单片机的数字压力表的设计

压力是重要的热工参数之一,各种气体、液体的压力测量在生产生活、工业现场、科学实验等领域有着广泛的应用。这里采用STM8S单片机作为主控制单元,提出一种新型数字压力表的设计方法。介绍压阻式压力传感器的测量原理和系统的整体框架,并描述相应的软硬件设计的方法,特别是在软件方面的处理,包括压力采集和标定校准算法。实验结果显示,压力数据显示较为稳定,能够满足基本的精度要求。设计的数字压力表简单,易用,便于携带。     

CMOS compatible bulk micromachined silicon piezoresistive accelerometer with low off-axis sensitivity

The CMOS compatible bulk micromachined piezoresistive accelerometer presented in this paper consists of four flexures supporting a proof mass. Four pairs of boron-diffused piezoresistors are located at maximum stress points on the flexures near the proof mass and frame ends. Because of the opposite nature of stress at the two ends, these piezoresistors can be connected to form a Wheatstone bridge such that the off-axis responses are practically cancelled while the on-axis (along perpendicular to proof mass) response is maximized. The device is simulated using CoventorWare. In the fabrication process, dual-doped TMAH solution is used for wet anisotropic etching. The novelty of this etching process is that the bulk micromachining can be performed after aluminum metallization. The etched surface is also smooth. The fabrication is thus CMOS compatible. The accelerometer exhibits good linearity over 0-10 g.     

板上芯片固化后残余应力分布的有限元模拟

用有限元模拟研究了板上芯片固化后残余应力的分布.在FR4及陶瓷分别作基板的两种情况下,残余应力分布最显著的差异是等效应力分布不同.讨论了基板厚度及粘合胶厚度对残余应力的影响,表明采用陶瓷基板时增加粘合胶的厚度以降低残余应力来作为低应力封装的一种手段是可行的.硅压阻传感芯片测量结果与计算机模拟结果的比较表明,计算机模拟值与实验测量值比较接近,测量值的正负区间与模拟值的正负区间吻合     

叠加电桥检测的加速度传感器的设计

This paper describes the design,simulation,processing and test result of a high sensitivity accelerometer based on the piezoresistive effect which uses an overlay bridge detection method.The structure of this accelerometer is supersymmetric "mass-beams".This accelerometer has 8 beams,where two varistors are put in the two ends.Four varistors compose a Wheatstone bridge and the output voltages of the 4 Wheatstone bridges have been superimposed as the final output voltage.The sensitivity of the accelerometer can be improved effectively by these clever methods. A simplified mathematical model has been created to analyze the mechanical properties of the sensor,then the finite element modeling and simulation have been used to verify the feasibility of the accelerometer.The results show that the sensitivity of the accelerometer is 1.1381 m V/g,which is about four times larger than that of the single bridge accelerometers and series bridge sensor.The bandwidth is 0-1000 Hz which is equal to that of the single bridge accelerometers and the series bridge sensor.The comparison reveals that the new overlay detection bridge method can improve the sensitivity of the sensor in the same bandwidth.Meanwhile,this method provides an effective method to improve the sensitivity of piezoresistive sensors.     

新型MOS晶体管式压力传感器

在应力作用下，MOS晶体管的源漏电流的大小会随着沟道区所受应力大小而变化。基于MOS晶体管的这种力敏效应，采用晶体管和电阻构成压敏电桥，提出了一种新型的MOS晶体管式压力传感器。该器件在与目前最常用的压阻式压力传感器相比，继承了其制作工艺简单、稳定性和线性度好等优点，大幅提高了传感器灵敏度并降低了功耗，使得器件性能得到整体提高。     

基于石墨烯压阻效应的压力传感器研究进展

与传统的硅阻型压力传感器、陶瓷型压力传感器相比,石墨烯压力传感器具有测量灵敏度更高、测量范围更广的优点。对几种石墨烯压力传感器的研究进展进行综述。根据制作工艺的不同,将石墨烯压力传感器分为单层型和多层型。根据两大类型,列举最近六种石墨烯压力传感器的基本制作过程和测量范围、检测灵敏度等特性。根据六种石墨烯压力传感器的对比结果,得到单层型与多层型石墨烯压力传感器的不同工作特性及应用环境。针对单层型和多层型石墨烯传感器,分别提出提高性能的可行方案,对此类传感器的实际应用与推广具有一定的指导意义。