A novel integrated microfluidic platform based on micro-magnetic sensor for magnetic bead manipulation and detection

We present a novel integrated microfluidic platform based on micro-magnetic sensor for manipulating and detecting magnetic beads (MB). A micro-spiral planar coil in MB manipulating system microfabricated by micro-electro-mechanical system technology is implemented to manipulate MB, and a giant magnetoimpedance (GMI) based micro-magnetic sensor is employed to detect the trapped MB. In our work, MB can be efficiently trapped by trapping force generated from micro-coil in microchannel. Next, trapped MB are detected by the changing ratio of impedance, as well as the variation of resistance and reactance in GMI sensor for trapped MB induce weak stray magnetic field under the magnetization by external magnetic field. The maximum difference of GMI ratio between with beads condition and without beads condition is 4.0% at the optimum driving frequency of 20 MHz under the external magnetic field of 15 Oe, and resistance ratio varies more significantly than reactance ratio. In comparison with traditional MB detecting methods by GMI sensor, the integrated microfluidic platform based on GMI sensor can not only manipulate and detect MB signal sensitively, but also enhance detection efficiency and decrease the experiment errors. Furthermore, this platform avoids contamination from the solutions in chemically reactive layers and reduces assay time in future biomarker detection. In our work, the microfluidic platform based on GMI sensor has potential applications in biomarker detection via MB manipulation and detection.     

Dynamic behavior of resonant piezoelectric cantilever as liquid level detection sensor

Resonant Piezoelectric-excited Millimeter-sized Cantilevers (PEMC), has attracted many researchers’ interest in the applications such as liquid level and density sensing. As in these applications, the PEMC are partially immersed in liquid, an appropriate analytical model is needed to predict the dynamic behavior of these devices. In this work, a PEMC has been fabricated for liquid level sensing. An analytical model based on Euler–Bernoulli beam theory and energy method is developed and applied to evaluate the performance of this device with respect to different tip immersion depth. To validate the proposed model, the theoretical results are compared with the experimental results for the tip immersion depth from 5 to 15?mm in water. The simulation results are in almost good agreement with experimental data. Using the proposed model, the two key parameters of sensor performance: sensitivity and working range have been examined for different mode shapes of PEMC vibration.     

基于表面等离子体共振传感器的尿微量白蛋白检测

检测尿微量白蛋白(MAU)可对轻微肾脏损害进行早期诊断,也可对高血压患者可能发生的心脑血管事件进行预测。实验将抗体通过巯基自组装固定于Au膜表面,研制了一种快速检测MAU的表面等离子体共振(SPR)生物传感器。结果表明:直接检测法可以检测到0.3μg/L的MAU,而纳米Au放大法检测限可以低至0.03μg/L。     

基于Magnet-MATLAB的微型磁通门联合仿真研究

针对Magnet在微型磁通门仿真分析时时间过长的问题,提出了一种将Magnet与MATLAB联合进行仿真分析的方法.基于Magnet建立磁通门探头3D模型,经仿真计算,得到被测磁场对应的感应线圈磁通;联合MATLAB将得到的感应线圈磁通转换为等效的小电流,经与激励电流叠加后,通过软件Flux提供的公式分别计算出受被测磁场影响下感应线圈磁通的变化情况;总磁通对时间求导,获得感生电压.在微型跑道型铁芯磁通门条件下,通过对Magnet仿真与Magnet-MATLAB联合仿真的计算结果比较表明:当外磁场小于5 μT时,2种仿真磁通门输出信号最为接近;与对全模型采用Magnet仿真计算用时超过30 h相比,联合仿真计算时间大幅减小,不超过10 min.     

一种扭转谐振式MEMS电场传感器

提出了一种基于微机电系统(MEMS)的扭转谐振式电场传感器。该微型电场传感器的感应电极与屏蔽电极采用共面叉指结构,首次采用扭转谐振的工作方式,显著提高了微型电场传感器的灵敏度。介绍了传感器的工作原理、结构设计、有限元仿真及实验。实验结果表明:在0～50 kV/m电场范围内,该传感器的线性度为0. 14%,3个往返行程的总不确定度优于0. 43%。在增益电阻为100 MΩ的情况下,传感器灵敏度达到4. 55 mV/(kV/m),相对已有传感器灵敏度提高了1个数量级。     

新型电场传感器应用于输电线电场测量

基于高性能的微电子机械系统(MEMS)工频电场传感器系统开展了高压架空输电线下电场测量应用研究.为了获得电场分布规律,基于模拟电荷法,建立了输电导线的二维电场计算通用模型.传感器系统核心敏感芯片基于电荷感应原理,采用MEMS技术加工制作.在0~1000kV/m工频电场范围内,传感器系统的总不确定度为1.53%,分辨力达到了20V/m.仿真与测试结果表明:35kV与10kV输电线下的电场计算结果与传感器系统的测量结果偏差分别为6%和10%,并与传统的Narda EFA-300电磁场分析仪测量结果具有较好的一致性.     

Analytical framework for adaptive compressive sensing for target detection within wireless visual sensor networks

Multimedia Tools and Applications - Wireless visual sensor networks (WVSNs) are composed of a large number of visual sensor nodes covering a specific geographical region. This paper addresses the...     

Design and fabrication of an alternating dielectric multi-layer device for surface plasmon resonance sensor

An alternating dielectric multi-layer device was fabricated and tested in the laboratory to show that dielectric mirrors of alternating high/low refractive index materials, based on the design of distributed Bragg reflector (DBR) for vertical cavity surface emission lasers (VCSELs), can be used in designing SPR biochemical sensors. The thickness, number of layers, and other design parameters of the device used were optimized using optical admittance loci analysis. The proof-of-concept device was fabricated with a symmetrical structure using Au/(SiO₂/TiO₂)₄/Au.Using a 632 nm-wavelength light source on a BK7 coupling prism, our laboratory tests showed that, under water, there was an 11.5° shift in resonant peak position towards the critical angle (from 74° in a conventional single-layer Au film), and a 3.25 times decrease in FWHM (the half-peak width). Our design also resulted in a wider dynamic range of up to a 1.50 refractive index unit (RIU), compared to 1.38 RIU in a conventional single-layer Au film. Using glucose solutions in ddH₂O, the calculated resolution was 1.28 × 10⁻⁵. The calculated intensity sensitivity was 10 000 a.u./RIU, about twice the improvement over the conventional single-layer Au film.     

一种简单便携的存储介质信息检测及备份装置研究

随着信息时代的飞速发展,数据信息在生活中的作用越来越显重要,数据恢复在社会生活中的应用越来越广,这便需要对存储介质的信息进行必要的检测和备份。虽然一些常见的软件可以通过PC端实现检测和备份功能,但也就是针对常见USB设备和一些专业性比较强的硬盘,不方便备份且不易携带,因此能提供一种兼容各种存储介质,并且方便使用、易于携带且不依赖于电脑就能实现检测和备份的设备非常重要。本文阐述了一种简单便携的存储介质信息检测及备份装置的研究设计．．     

A trapezoidal cantilever density sensor based on MEMS technology

A trapezoidal cantilever density sensor is developed based on micro-electro-mechanical systems (MEMS) technology. The sensor measures fluid density through the relationship between the density and the resonant frequency of the cantilever immersed in the fluid. To improve the sensitivity of the sensor, the modal and harmonic response analyses of trapezoidal and rectangular cantilevers are simulated by ANSYS software. The higher the resonant frequency of the cantilever immersed in the fluid, the higher the sensitivity of the sensor; the higher the resonant strain value, the easier the detection of the output signal of the sensor. Based on the results of simulation, the trapezoidal cantilever is selected to measure the densities of dimethyl silicone and toluene at the temperature ranges of 30 to 55 °C and 26 to 34 °C, respectively. Experimental results show that the trapezoidal cantilever density sensor has a good performance.     

新型地铁速度传感器检测系统设计

设计一种能检测光电式和霍尔式两种不同类型的新型地铁速度传感器检测系统,以PCI—8348AJ高速并行数据采集卡作为数据采集核心,用V20型变频器来操控电机的转速,模拟地铁在不同时速下速度传感器的性能。该系统的软件用VC＋＋编写,主要包括转速根据轮径值转换成相应速度的计算,速度传感器信号周期计算、占空比计算、两路信号相位差计算。以TQG19型霍尔速度传感器作为待测设备,通过实验证明：所设计的检测系统稳定性高,实时性强,检测精度够达到0.7%。     

适宜动态检测的新型谐振式水晶温度传感器

成功地研制一种适宜动态温度检测的厚度切变C模工作的压电谐振式水晶温度传感器。它采用NLSC切型 ,变形的平凸结构 ,谐振频率为 19.5MHz。实测表明 ,其Q值为 2 1.3× 10 4 ,电容比为 72 0 ,温度系数为 18.8× 10 -6/℃。响应速度为 2s,经 15 0 0次热冲击试验 ,准确度不变。     

烟支湿度与密度检测的微波谐振腔传感器研究

对微波谐振腔微扰法检测基本理论和工作原理进行了论述,对微波作用的介电材料的电磁参数"介电常数"和"介电损耗"产生的相对变化进行了分析讨论,建立了烟支密度和湿度与谐振腔谐振曲线的频偏及半功率点带宽的数学表达式,设计制作了重入式微波谐振腔传感器.采用TM010谐振模,对烟支的密度和湿度进行了实时检测.以扫频法检测谐振腔空腔和有烟支状态下的幅频特性,获得谐振频率f、峰值功率p及半功率带宽ω.根据相关数学式得到了烟支的湿度和密度.该检测方法具有快速、连续、分辨力高、无污染和操作安全简便等优点.并且适用于工业现场在线测量.     

MEMS cantilever sensor for non-destructive metrology within high-aspect-ratio micro holes

Tactile metrology with deep and narrow micro holes was addressed using extremely slender piezoresistive micro cantilever sensors. Linear strain–displacement characteristics were observed with this sensor operated under transversal and axial loading. From noise, non-linearity and repeatability measurements the resolution and uncertainty of the cantilever sensors were determined to few nm and few tens of nm, respectively, within a micron displacement span. Under axial loading buckling of the cantilevers was observed after exceeding the critical limit of an Euler beam under the boundary conditions of a clamped-pinned beam. The cantilevers typically survived displacements well above the buckling limit, i.e., fracture of 3-mm long cantilevers was only observed at displacements of more than 200 μm. The feasibility of the cantilever as an active 1D touch probe for high-aspect-ratio blind holes was demonstrated at a dry-etched silicon high-aspect-ratio microstructure. As an application example with a high-volume product we investigated the form and roughness of diesel injector nozzle spray holes.     

支持区分服务的无线传感器网络802.11 MAC协议

针对无线传感器网络不能提供数据流优先级区分的问题,提出了一种基于IEEE802.11MAC协议的改进机制。该机制通过引入新的控制分组,使目的节点可以拒绝接收来自低优先级节点的数据,从而确保了高优先级数据业务的服务质量。数学分析表明,该机制能够使高优先级数据流占用更多的带宽,并且降低了高优先级数据流的分组丢弃概率。能耗分析表明,高优先级数据业务能耗低于低优先级数据业务,随着节点密度的增加,该机制节能效果逐渐明显,适合于节点密度高的无线传感器网络。     

基于鼠精细胞的味觉阻抗传感器 用于苦味物质检测的研究

本文设计了一种基于雄鼠精细胞的细胞阻抗传感器用于苦味物质的特异性检测.雄鼠精细胞内含有大量T2Rs受体(G蛋白偶联受体)可以对苦味物质产生特异性响应,苦味受体被苦味物质激活后产生的响应会引起细胞形态骨架的变化,从而可以被细胞阻抗传感器检测.本文探索了实验的最佳细胞密度,检测了苯硫脲和奎宁两种常见的苦味物质的响应,苯硫脲检测范围为10μmol/L~200μmol/L,检出限为4μmol/L;奎宁检测范围为62.5μmol/L~1000μmol/L,检出限为40μmol/L.传感器阻抗值增量与苦味物质浓度呈一定的线性相关性.此外,论文对该味觉传感器的特异性进行了测试分析,表明了基于细胞传感器的检测方法为代替动物和人的苦味测试提供了一种可能的新的手段.     

基于透射齿轮盘的脉冲与电压双测速装置

设计了一种采用透射式齿轮盘的电机测速装置.该设计采用槽型光电传感器配合自制的透射式齿轮盘来采集速度信号,产生一系列数字脉冲信号,同时采用频率-电压转换芯片LM2907将脉冲信号转化为电压信号.此装置应用于模型车上,不仅可以实现脉冲测速,还可实现电压测速,具有结构简单,安装方便,检测方式多样,检测精度高等特点.     

变宽度悬臂梁的FBG流速传感器

通过对光纤传感器进行设计,提出了一种基于变宽度悬臂梁的光纤(Bragg)光栅(FBG)流速传感器.传感部分由不锈钢材质的悬臂梁和粘贴在其特定位置上的FBG构成,悬臂梁采用等腰梯形和矩形相结合的外形结构设计,传感头两部分之间的衔接不需要用销子固定,整个传感头浑然一体,无额外附加重量,制作方法简易,且实验设置参考光栅,实验结果不受温度变化的影响.实验表明:传感器的Bragg波长漂移量与流速变化有很好的线性关系,传感器的灵敏度为0.025 m/s.可测流速范围为0～2 m/s,传感器不仅实现了对温度的补偿,而且提高了测量精度、灵敏度.     

Silicon cantilever sensor for micro-/nanoscale dimension and force metrology

A piezoresistive silicon cantilever-type tactile sensor was described as well as its application for dimensional metrology with high-aspect-ratio micro components and as a transferable force standard in the micro-to-nano Newton range. As an example for micro-/nanoscale tactile probing metrology the novel cantilever sensor was used for surface scanning with calibrated groove and roughness artifacts. Micro-/nano-Newton force metrology using the novel cantilever sensor was addressed with calibration procedures which were developed for low-force stylus instruments as well as for glass micro pipettes designed for the manipulation of isolated living cells.     

汽车ABS测速传感器齿圈缺陷检测装置设计

目前生产线上的汽车防抱死制动系统(ABS)测速传感器齿圈质量检测均采用人工目视法,其劳动强度大、误检率高、效率低.研究了一种ABS齿圈缺陷检测装置.综合利用转换测量技术、数据采集技术以及自动控制技术,通过反射型光纤传感器实现对齿圈的自动扫描和缺陷检测.经实际运行检测,证明该装置可靠性高、稳定性好,软件界面友好,误检率不大于1％,检测速度达到10 s/PCS,能快速检测齿圈是否合格,有效提高了齿圈的检测效率和准确性,确保了齿圈的出厂合格率在100％的水平.