GMR生物传感器的原理及研究现状

GMR生物传感器包括三个部分,即免疫磁性微球、高灵敏度GMR传感器以及相关读出电路。与其他生物传感器相比,它具有灵敏度高、分辨力强、价格低、市场普及潜力大、设备小型化及测量过程自动化等优点。综述了GMR生物传感器的研究现状,对相关技术的工作原理进行了分析,提出了GMR生物传感器的应用前景和有待解决的问题。     

GMR生物传感器的原理及研究现状

GMR生物传感器包括三个部分,即免疫磁性微球、高灵敏度GMR传感器以及相关读出电路.与其他生物传感器相比,它具有灵敏度高、分辨力强、价格低、市场普及潜力大、设备小型化及测量过程自动化等优点.综述了GMR生物传感器的研究现状,对相关技术的工作原理进行了分析,提出了GMR生物传感器的应用前景和有待解决的问题.     

巨磁电阻传感器

利用材料的巨磁电阻 (GMR)效应 ,可制得新一类磁电阻传感器—— GMR传感器。与传统的磁阻传感器相比 ,GMR传感器具有灵敏度高、可靠性好、测量范围宽、抗恶劣环境、体积小等优点 ,有广泛的应用前景。本文就目前已商业化的几种 GMR传感器的工作原理作一评述     

基于GMR效应的新型生物传感器研究

制备出了结构为Ta/NiFe/CoFe/Cu/CoFe/MnIr/Ta，磁阻变化达9.2%的GMR自旋阀传感器，并用该种传感器对浓度为200μg/mL、直径2μm的生物免疫磁球溶液进行了检测。实验结果表明，该生物传感器可以对被测生物免疫磁球溶液产生平均350μV的电压输出信号，随着磁球溶液的继续增加，电压输出信号可以达到最大值450μV。除去背景干扰信号的影响，由磁球产生的有效电压输出信号为300μV。此外，交流励磁场的频率的增加也会使输出电压信号减小。     

基于集成技术的二维智能焊缝传感器

本文简述了基于GMR的二维焊缝检测传感器.为解决焊接加工自动化过程中焊缝的跟踪检测,将GMR焊枪悬浮高度传感器、焊缝检测传感器以及相应的微处理器有机集成,从而使传感器实现小型化智能化,减少对工件检测的死区范围.该传感器与自动焊接机组成的焊缝跟踪系统,焊缝跟踪精度高、响应速度块,减少了焊缝轨迹空间捕捉算法的复杂性.     

基于GMR效应的新型生物传感器研究

制备出了结构为Ta/NiFe/CoFe/Cu/CoFe/MnIr/Ta,磁阻变化达9.2%的GMR自旋阀传感器,并用该种传感器对浓度为200μg/mL、直径2μm的生物免疫磁球溶液进行了检测。实验结果表明,该生物传感器可以对被测生物免疫磁球溶液产生平均350μV的电压输出信号,随着磁球溶液的继续增加,电压输出信号可以达到最大值450μV。除去背景干扰信号的影响,由磁球产生的有效电压输出信号为300μV。此外,交流励磁场的频率的增加也会使输出电压信号减小。     

基于巨磁电阻的地磁传感器设计

介绍一种新型地磁传感器,该传感器由单轴巨磁电阻传感器捷联构成。通过外加磁通聚集器和磁偏置技术改进GMR传感器的输出特性,使地磁场的大小位于传感器输出曲线的线性范围内。用ANSYS对永磁体的偏置磁场进行数值模拟,ANSYS能根据偏置磁场快速地确定出永磁体的相关参数。该传感器具有结构简单、灵敏度高等优点,可以较好应用于地磁场测量。     

基于GMR效应的新型生物传感器研究

制备出了结构为Ta/NiFe/CoFe/Cu/CoFe/MnIr/Ta,磁阻变化达9.2%的GMR自旋阀传感器,并用该种传感器对浓度为200 μg/mL、直径2μm的生物免疫磁球溶液进行了检测.实验结果表明,该生物传感器可以对被测生物免疫磁球溶液产生平均350 μV的电压输出信号,随着磁球溶液的继续增加,电压输出信号可以达到最大值450 μV.除去背景干扰信号的影响,由磁球产生的有效电压输出信号为300 μV.此外,交流励磁场的频率的增加也会使输出电压信号减小.     

具有CoCrPt硬磁偏置的微尺寸巨磁阻传感器

本文介绍了一种基于GMR自旋阀的磁场传感器,它用于读取磁记录信息,并且通过硬磁偏置层解决了小尺寸GMR中存在的巴克豪森噪声问题. 传感器采用顶钉扎的自旋阀结构的GMR,磁电阻经过优化达到13.2%. 自旋阀的自由层被CoCrPt永磁体磁化到和被钉扎层的磁化方向相互垂直,这样可以使磁传感器得到线性的磁场探测性能. 对磁场传感器经过测试发现,硬磁偏置层在磁化后相较于磁化前,磁传感器的MR-H曲线得到明显改善,且矫顽力降低.     

基于GMR传感器阵列的生物检测研究

利用磁性传感器,特别是GMR传感器,对生物特异性反应进行检测,从而解决传统荧光检测存在的标记易失、可重复性差,对设备和技术人员要求高等缺点.采用超顺磁磁珠作为磁性标记物,将其与被测生物分子充分结合后固定在芯片表面,再通过磁阻传感器的磁阻变化检测磁性标记的存在.采用高灵敏度的GMR传感器和磁性含量高的磁性颗粒,减小标记与传感器之间的距离和尺度差异,能提高阵列生物检测性能.将GMR传感器阵列应用在生物检测上是极具发展前途的研究方向,通过对已有方案的改良或选用新型的材料,最终会实现磁性生物传感器灵敏、快速、便捷的实际应用.     

高检测灵敏度的DNA生物传感器

基于磁珠带标记DNA电化学传感器、磁珠标记的GMR(TMR)DNA生物传感器和纳米线场效应DNA生物传感器都具有高检测灵敏度的特点,是极具发展前途的研究方向。主要介绍了以上三种高检测灵敏度DNA生物传感器的基本检测原理,并对比分析了这三种传感器的优缺点。     

用于巨磁阻生物传感器检测的模拟前端电路

提出一种用于巨磁阻(GMR)生物传感器检测的模拟前端电路。电路采用电压检测的方法,包括基准电压源,单位增益缓冲器,电荷转移型开关电容采样保持电路,流水线模数转换器四部分;基准电压源用于产生传感器阵列的片内激励电压;传感器阵列的检测输出电压经单位增益缓冲器后,由开关电容采样保持电路进行采样,保持,放大;最后经过流水线模数转换器输出数字码流;芯片采用SMIC 0.18μm 1P6M CMOS厚栅氧工艺实现。测试结果表明,在电源电压3.3 V,20 MHz时钟下测试,整体电路输出信号有效精度达到7.2 bit,功耗33 mW,满足GMR生物传感器的检测要求。     

Analysis of tree‐based multicast routing in wireless sensor networks with varying network metrics

Wireless ad hoc and sensor networks are emerging with advances in electronic device technology, wireless communications and mobile computing with flexible and adaptable features. Routing protocols act as an interface between the lower and higher layers of the network protocol stack. Depending on the size of target nodes, routing techniques are classified into unicast, multicast and broadcast protocols. In this article, we give analysis and performance evaluation of tree‐based multicast routing in wireless sensor networks with varying network metrics. Geographic multicast routing (GMR) and its variations are used extensively in sensor networks. Multicast routing protocols considered in the analytical model are GMR, distributed GMR, demand scalable GMR, hierarchical GMR, destination clustering GMR and sink‐initiated GMR. Simulations are given with comparative analysis based on varying network metrics such as multicast group size, number of sink nodes, average multicast latency, number of clusters, packet delivery ratio, energy cost ratio and link failure rate. Analytical results indicate that wireless sensor network multicast routing protocols operate on the node structure (such as hierarchical, clustered, distributed, dense and sparse networks) and application specific parameters. Simulations indicate that hierarchical GMR is used for generic multicast applications and that destination clustering GMR and demand scalable GMR are used for distributed multicast applications. Copyright © 2012 John Wiley & Sons, Ltd.     

Photonic-Crystal-Slab-Type Guided Mode Resonance Filters in Infrared Range

Transmission characteristics of photonic crystal (PhC)-slab-type guided mode resonance (GMR) filters in the infrared range (4–10 $mu$m) are studied numerically and experimentally. Using a finite-difference time-domain method, the dependencies of the spectral response with the depth and size of holes are investigated and analyzed. The GMR filters were fabricated on a silicon-on-insulator wafer and the experimental transmission spectra were compared with the simulations. In this context, we identified a list of conditions for the realization of PhC-slab-type GMR filters in the infrared range.      

Cu88Co12合金的巨磁电阻及其微结构的研究

本文利用场离子显微镜－原子探针及电镜研究了具有巨磁电阻效应的甩带Ｃｕ８８Ｃ ｏ１２合金的微结构。Ｃｕ８８Ｃｏ１２合金经４５０℃退火半小时后发邓有明显的巨磁电阻。     

Monolithic integration of Giant Magnetoresistance (GMR) devices onto standard processed CMOS dies

Giant Magnetoresistance (GMR) based technology is nowadays the preferred option for low magnetic fields sensing in disciplines such as biotechnology or microelectronics. Their compatibility with standard CMOS processes is currently investigated as a key point for the development of novel applications, requiring compact electronic readout. In this paper, such compatibility has been experimentally studied with two particular non-dedicated CMOS standards: 0.35 μm from AMS (Austria MicroSystems) and 2.5 μm from CNM (Centre Nacional de Microelectrònica, Barcelona) as representative examples. GMR test devices have been designed and fabricated onto processed chips from both technologies. In order to evaluate so obtained devices, an extended characterization has been carried out including DC magnetic measurements and noise analysis. Moreover, a 2D-FEM (Finite Element Method) model, including the dependence of the GMR device resistance with the magnetic field, has been also developed and simulated. Its potential use as electric current sensors at the integrated circuit level has also been demonstrated.     

基于GMR生物传感器的甲胎蛋白检测

采用磁控溅射、光刻、离子束刻蚀和剥离工艺等工艺和方法,制备了多层膜结构的巨磁阻(GMR)生物传感器件,并利用此种传感器来检测甲胎蛋白。在传感器表面通过生物处理固定甲胎蛋白单克隆抗体(McAb1)作为探针,以捕获目标抗原———甲胎蛋白。用直径1μm的超顺磁磁珠标记目标抗原。当传感器表面抗体将目标抗原捕获后,磁珠标记即被固定在GMR传感器的表面。垂直于传感器表面施加230 Oe(1 Am-1=4π×10-3 Oe)的磁场,即可检测到由磁珠产生的信号。本实验对质量浓度为1 ng/mL的甲胎蛋白进行了检测,得到了信号为0.29～0.34Ω的电阻变化值。此种检测方法可用于诊断原发性肝癌。