LiNbO3棱镜耦合双金属薄膜表面等离子共振传感器

高折射率铌酸锂(LiNbO3)(2.202)为棱镜耦合激发的角度调制型表面等离子共振传感器,利用反射率公式优化单层银膜、金膜和双层银/金膜传感器薄膜的厚度,分别计算了优化厚度的传感器在检测样品折射率为1.330时的共振角、灵敏度、峰值半宽度(FWHM)和品质因数(FOM),理论计算表明:双层金属薄膜,随着金膜厚度的增加,传感器灵敏度增加,但峰值半宽度增加,品质因数下降.综合考虑,选择银/金(41/5)优化组合,传感器品质因数为优化的单层金膜(47 nm)传感器品质因数的2倍以上,另外,与常用的BK7玻璃棱镜耦合相比,LiNbO3棱镜耦合具有较大的样品动态检测范围.优化厚度的传感器实验检测糖水浓度表明:糖水浓度与共振角为线性比例关系.     

玻璃助剂对厚膜NTC热敏电阻器的性能影响

系统研究了Mn-Co-Ni系厚膜NTC热敏电阻器的电阻性能与玻璃助剂质量分数的关系,结果表明:当玻璃助剂质量分数为(10～30)×10-2时,电阻性能参数(RT,ρT,B和αT)随玻璃助剂质量分数的增加而显著增长;当玻璃助剂质量分数继续增加,则电阻性能参数基本不变.但当玻璃助剂质量分数为5×10-2时,厚膜电阻因烧结性能变差而导致电阻性能不稳定,同时,电阻性能参数均异常增大.当玻璃助剂质量分数为30×10-2以上时,采用本工艺制备的厚膜NTC热敏电阻器具有良好的工艺性和热稳定性.     

表面等离子体共振传感器的仿真

为了得到基于相位检测、角度检测和波长检测的表面等离子体共振(SPR)生物传感器的高检测精度,利用Matlab建立了Kretschmann模型SPR传感器的数值仿真软件.系统地进行了棱镜折射率、测试介质折射率、金膜的厚度等因素对3种不同检测方式的SPR曲线的影响.理论分析结果表明:角度调制时与介质折射率增加时,SPR角也相应增加,相位检测对传感层的折射率具有选择性.     

菲涅耳双棱镜干涉的仿真模型设计

利用软件技术对菲涅耳双棱镜干涉现象进行模拟设计,建立了模拟菲涅耳双棱镜干涉的数学模型,运用模块化程序设计思想设计了模型的模块化结构,并开发了仿真模型核心模块的程序,该模型能很好地动态模拟菲涅耳双棱镜干涉.     

光学薄膜技术及在背光模组中的应用研究

本文介绍了传统光学薄膜的相关原理,并根据薄膜干涉的基本原理和特征,论述了用于背光模组的光学薄膜(反射膜、扩散膜、棱镜膜)的性能和制备工艺。     

表面等离子共振Ag/TiO2复合膜气体传感器

提出一种新型的Ag／TiO2复合膜三甲胺（TMA）气敏光化学表面等离子共振（SPR）传感器结构。结构中使用一只金红石材料作成的棱镜作为耦合棱镜,在棱镜的底边采用射频溅射技术制作Ag／TiO2复合膜,Ag膜和TiO2膜的厚度分别为50nm和100nm,在复合膜上设置待测气体的样品池。在He-Ne光入射激励下,复合膜的分界面发生SPR现象。实验结果表明：SPR角与TMA气体的体积分数基本呈线性比例关系。     

表面等离子共振Ag-SnO_2薄膜光化学气体传感器

提出一种新型的Ag-SnO2复合膜H2S光化学表面等离子共振(SPR)气体传感器结构。结构中使用一只金红石材料作成的棱镜作为耦合棱镜,在棱镜的底边采用射频溅射技术制作Ag-SnO2复合膜(CuO为掺杂质),Ag膜和SnO2膜的厚度分别为50 nm和100 nm,在复合膜上设置待测气体的样品池。在白光入射激励下,复合膜的分界面发生SPR现象。实验结果表明:SPR的波长与H2S气体的体积分数基本呈线性关系。     

基于银膜-石墨烯复合膜对称结构的SPR传感器研究

针对棱镜激励银膜SPR传感器灵敏度虽然较金膜结构高,但易被氧化、稳定性较差的缺点,提出一种棱镜耦合激励银膜－石墨烯－介质－石墨烯－银膜复合膜对称结构的SPR传感器,增加石墨烯膜层,解决银膜SPR传感器易氧化导致稳定性下降问题,采用角度调制的方法对SPR传感结构进行了性能参数分析,研究了金属材质、石墨烯以及检测介质的厚度对传感性能的影响。结果表明,银膜相比金膜,具有更好的共振效果,灵敏度较高,通过调节检测介质的厚度,可以改变角度的调节范围,实现了传感器的可调性,对称传感结构可以产生双共振峰SPR曲线,为分布式传感提供了可供参考的依据,石墨烯优化并提高了传感器的稳定性和检测灵敏度。     

吸附甘氨酸对多壁碳纳米管电性能的影响

以磁控贱射的方法在玻璃基底上制作叉指银电极,用丝网印刷技术制备碳纳米管膜。室温下测试吸附甘氨酸前后碳纳米管膜伏安特性和电阻率的变化,发现吸附了甘氨酸后碳纳米管的导电能力增加,且增加的幅度与甘氨酸的浓度有关。实验结果预示:碳纳米管是一种良好的室温下检测甘氨酸的敏感材料。对碳纳米管吸附甘氨酸前后电性能的变化机理进行了初步的探讨。     

棱镜耦合自动测试系统设计

基于单片机与PC上位机,设计了包括硬件和软件的棱镜耦合自动测试系统。该系统控制了步进电机的运转状态,实现了光强数据的自动采集、处理,并通过软件完成数据存储、分析及图形显示。实验结果表明,该系统满足棱镜耦合技术要求,实验效果良好,实现了高精度、高自动测试的棱镜耦合技术。     

SPR enhanced ellipsometric gas monitoring on thin iron doped tin oxide layers

In this work, thin iron doped tin oxide layers (3–6 nm) were investigated with regard to gas sensitivity by means of surface plasmon resonance (SPR) effect with ellipsometric readout. The experimental set-up was a Kretschmann configuration with gold as metal layer. The sensor system was exposed to different concentrations of methane in the low ppm range and the sensor response of an uncoated gold layer compared to a gold layer coated with iron doped tin oxide. The additional layer effects stability with regard to drift behavior of the sensor and an increase in sensitivity. Furthermore, the sensor is able to detect the toxic gas carbon monoxide in low concentration range (down to 0.5 ppm). The thin layers were investigated by X-ray photoelectron spectroscopy, secondary electron microscopy and spectroscopic ellipsometry. The possible mechanisms taking place on the surface are discussed.     

Sensitivity enhancement of a surface plasmon resonance based biomolecules sensor using graphene and silicon layers

A surface plasmon resonance based biomolecules sensor using silicon and graphene layers coated over the base of the high index prism sputtered with gold has been analyzed. The graphene layer has been used to enhance the adsorption of biomolecules while the addition of silicon layer between gold and graphene increases the sensitivity. The thicknesses of gold and silicon layers along with the number of graphene layers have been optimized to achieve the best performance of the sensor in terms of sensitivity and Full Width at Half Maximum (FWHM). To see the effect of wavelength of the light source, simulations have been carried out for three different wavelengths. The best performance is obtained for 633 nm wavelength with optimized thicknesses of gold and silicon layers as 40 nm and 7 nm respectively while the optimum number of graphene layers is 2. The sensitivity obtained with optimized parameters and additional silicon layer, is more than twice the value reported in the literature.     

Use of a low refractive index prism in surface plasmon resonance biosensing

A way to improve the angular sensitivity of surface plasmon resonance (SPR) biosensor by tuning the resonance position to a higher incident angle region using a lower refractive index glass prism is described in this paper. A novel effective 3-layer (E3L) model is described to transform a multiple layer biosensor configuration in context of SPR condition. The E3L model supports the use of a low refractive index prism for biosensing. The performance of the sensor in immunosensing is checked for two glass prisms of different refractive index materials. The experimental results showed an enhancement in the amount of resonance angle shift of the immunosensor for the lower refractive index glass prism.     

中国微米纳米-微纳结构对电容式柔性压力传感器性能影响的研究

设计制备出三明治结构的电容式柔性压力传感器,并对其性能进行研究.该传感器以银纳米线为电极材料,聚二甲基硅氧烷(PDMS)为柔性衬底,同时采用毛面玻璃和光面玻璃分别作为柔性衬底的制备模板,制备出微纳结构和平面结构的PDMS薄膜.然后采用喷涂法制备AgNWs/PDMS复合电极,以另外一层PDMS为介电层,将两电极面对面封装,得到电容式柔性压力传感器,最后系统研究了传感器的电极微纳结构对器件性能的影响.本文研究表明,具有微纳结构的AgNWs/PDMS复合薄膜传感器的灵敏度为1.0 kPa-1,而平面结构的AgNWs/PDMS复合薄膜传感器的灵敏度为0.6 kPa-1,由此可知具有微纳结构的柔性衬底能够显著提高器件的灵敏度.     

一种小型化SPR生物传感器的设计与实现

介绍了一种采用不规则四边形棱镜设计的小型化表面等离子体共振(SPR)生物传感器。棱镜结构与已有的TI Spreeta传感器类似,但是在尺寸、光学性能等方面做了较大优化。新研制的SPR传感器在光学检测精度和系统集成性等方面也有了很大提高。在光路设计中,采用波长为630 nm的宽光束红光LED作为光源,5 000像素点线阵CCD作为光电检测器,光学检测效果要大大优于TI Spreeta波长为830 nm的近红外光源和128像素点的线阵硅光二极管。在光路优化的同时,系统集成了流动控制模块、信号采集处理模块,形成了一个可实现生物大分子相互作用分析的集成小型化SPR检测装置。利用空气、水及乙醇等进行的SPR实验表明:该装置能够对单一样本进行精确检测,共振角的检测精度高达0.01°,且检测结果线性度高,稳定性好,单一样本的检测偏差小于0.5%。     

An adsorption-based mercury sensor with continuous readout

A novel readout procedure for a mercury sensor has been proposed. The sensor is based on the surface adsorption. Mercury vapor is adsorbed at the surface of a thin gold layer patterned into four meanders which are connected into a Wheatstone bridge configuration. Sensing is achieved by the resistivity change of the gold film during mercury adsorption. Direct output from the sensor is electric voltage. It takes an additional procedure to convert voltage to mercury concentration. This type of sensor is improved by introducing continuous readout procedure for the voltage–concentration conversion. By using this readout procedure it is possible to monitor mercury vapor concentration as a function of time. Readout is based on the Langmuir time–dependent adsorption theory. This paper illustrates a practical implementation of the new readout procedure.     

基于OPNET的无线传感器网络节点跨层设计

无线传感器网络是一类由大量位置相对固定的节点所组成的无线通信网络,其节点能量、计算和通信能力都非常有限,因此,传统网络的层次设计和网络协议都难以应用到无线传感器网络中。为解决这些问题,该文在传统网络层次设计思想的基础上,提出了适用于无线传感器网络节点的跨层网络模型,基于OPNET网络仿真工具实现了节点的跨层网络模型设计,在此基础上实现了无线传感器网络中路由选择和数据汇聚等典型应用的仿真。结果表明,新的跨层网络模型能够很好地描述节点各个层次的功能,便于网络协议的综合设计和集中优化。     

Sensing Assessment in Unknown Environments: A Survey

This paper surveys sensing assessment solutions from the literature with a particular focus on techniques which can be used in unknown environments, including the following: sensor fault detection and identification (FDI), sensor or source evaluation, and isolating poorly sensed regions. Each approach is evaluated in terms of its ability to perform sensing assessment tasks in unknown environments and its coverage of the range of potential sensing problems. These tasks include sensing problem detection and characterization, as well as performance evaluation (e.g., estimating accuracy or reliability), for a sensor or group of sensors. This survey shows that over 40 existing approaches are focused on either detection and identification of traditional sensor faults (e.g., drift or physical damage) in known environments or evaluation of the reliability of a source (e.g., sensor or agent). Only eight approaches surveyed have tackled environment-dependent problems (e.g., exteroceptive sensor FDI, miscalibration, or use of an inappropriate sensor) in a useful manner for unknown environments. Even less work (two studies) appears to have been done on isolating poorly sensed regions. The survey concludes with a list of opportunities for future research, including developing methods for detecting and characterizing environment-dependent problems and creating comprehensive sensing assessment systems.     

An optical sensor for nitrogen dioxide based on a copper phthalocyanine Langmuir—Blodgett film

A copper phthalocyanine Langmuir—Blodgett film has been incorporated in an optical gas sensor which exploits the phenomenon of surface plasmon resonance. For the detection of nitrogen dioxide, a significant improvement over previous work is demonstrated. The use of an ultra-thin layer of nickel to protect the underlying silver layer is also reported.