一种高分辨力柔性触觉传感器

本文描述了一种基于全内反射原理，用透明橡胶材料作为波导板的柔性触觉传感器。该传感器除具有一般刚性波导板触觉传感器的高分辨力等特点外，还具有柔性好，力灵敏阈值低，不怕碰撞等特点，该传感器特别适合装在智能机器人手爪上，为机器人系统高效率地获取物体形状，位置和姿态信息，实现智能抓握物体，操作物体等功能提供了有效的手段。     

平面内谐振式微悬臂梁生化传感器的设计与制造

给出了一种新型的基于平面内谐振模态的电热驱动微悬臂梁的工作原理和制造方案。相比于传统的平面外谐振模态谐振式悬臂梁,该设计能有效地降低微悬臂梁在液体中工作时的拖曳力,从而降低其振动能量损失,使得其接入锁相环接口电路后的闭环品质因数达到了249。电热驱动和压阻检测方式便于工艺集成和快速检测。本文给出了基于SOI硅片和深反应离子刻蚀(DRIE)的悬臂梁制作方案,并分别在空气和水中对悬臂梁的谐振特性进行了测试。     

Potential of near-field microwave imaging in breast cancer detection utilizing tapered rectangular waveguide probes

Microwave imaging for medical applications has been of interest for many years. A novel near-field microwave non-invasive testing and evaluation (NIT&E) technique utilizing tapered rectangular waveguide probes is presented for breast cancer detection. Near-field microwave NIT&E techniques can be a successful candidate for the detection of breast cancer because of their potential in dealing with materials of low conductivity (i.e. lossy dielectrics like the breast tissue). The physical basis for breast tumor detection with microwave imaging is the contrast in dielectric properties of normal and malignant breast tissues. A method adopting Fourier transform matching (FTM) technique and utilizing the reflection coefficient at the aperture of a tapered rectangular waveguide sensor radiating into a breast is described resulting in microwave images that indicate the presence of a tumor. These images demonstrate the feasibility of detecting breast tumors using this approach.     

A Micromachined Inline-Type Wideband Microwave Power Sensor Based on GaAs MMIC Technology

Wideband 8–12-GHz inline-type microwave power sensors that are based on measuring the microwave power coupled from the coplanar waveguide line by a microelectromechanical systems membrane are presented. In this method, the signal is available during the power detection. In order to obtain the low reflection losses and insertion losses, as well as the wideband response of the power sensor, an impedance match structure and a compensating capacitance are proposed. The fabrication of the power sensor is compatible with the GaAs monolithic microwave integrated circuit (MMIC) process. The experimental results show that the sensor has reflection losses better than 20 dB and insertion losses less than 0.45 dB up to 12 GHz. A sensitivity of more than 30 $muhbox{V/mW}$ and a resolution of 0.2 mW are obtained at the 10-GHz frequency.$hfill$[2008-0219]      

应力型微悬臂梁生化传感器响应机理研究进展

针对静态微悬臂梁表面特异性结合产生表面应力信号的响应机制问题,介绍了微悬臂梁生化传感器的工作原理,阐述了应力响应机制的简化模型,从纵向界面上和横向分子间2个方面对特异性吸附引起的悬臂梁表面应力的变化进行了剖析,讨论了界面能变化、位阻作用、静电力、氢键作用等与表面应力大小及方向之间的关系,总结了应力型微悬臂梁生化传感器的响应机理的研究。     

Performance of integrated optical microcavities for refractive index and fluorescence sensing

The performance of a novel sensor based on an integrated optical (IO) disk microcavity (MC) is theoretically studied. The MC is a resonant waveguide structure in which multiple interference of a guided mode occurs. At resonance, the MC is extremely sensitive to refractive index changes and it sustains locally enhanced optical field. Therefore, the MC is naturally suitable as an extremely responsive sensor for measuring minute changes in refractive index and/or fluorescence of an analyte. Combination of multiple interference and extremely small sampling volume (few femtoliters) provides unique sensitivity of the MC device. A factor of 9 increase in fluorescence sensitivity versus waveguide sensor is anticipated. Provided shot-noise limited detection, the refractive index resolution down to 10⁻⁹ is feasible with the MC sensor, which exceeds that of the straight waveguide interferometer by the order of magnitude. MC-sensors can be combined into arrays providing high throughput detection of both labeled and non-fluorescent biological species.     

Metallo-porphyrin zinc as gas sensitive material for colorimetric gas sensors on planar optical waveguides

The presented work focuses on the investigations of a metallo-porphyrin and its gasochromic behavior to different gases. Gasochromic materials change their color while they are exposed to a certain gas. So they offer the possibility to develop highly selective chemical gas sensors and gas sensing systems. The focus of this work is the characterization of the metallo-porphyrin 5, 10, 15, 20-tetraphenylporphyrin-zinc (ZnTPP). Nonetheless, there is a wide range of other possible metallo-porphyrins. When embedded into a polymeric matrix (PVC) a color change to the toxic gas NO₂ can be detected. To develop a stand-alone gas sensor, the porphyrin/PVC matrix is deposited onto a planar optical waveguide. The color change of the porphyrin dye can be detected in the evanescent field of the optical waveguide. Therefore, the light of a high power LED is coupled into the waveguide. The color change of the porphyrin is detectable with photodiodes as a variation of the out-coupled light intensity. The sensor shows no unwished sensitivities to CO₂ and CO and only low to NH₃. NO₂ is detectable with a resolution of 1?ppm.     

波导传感器中高效柱面波平面波转换结构的变换光学设计

基于阻抗可调的变换光学理论,设计了波导传感器中二维平面波和柱面波相互转换的光学结构。通过在虚拟空间设置合适的阻抗函数,变换介质边界上的反射得到有效消除,实现了高效的平面波到柱面波转换;转换效率将随着输入波束宽度的增加而提高。四个相似转换结构的组合,可实现高效柱面波-平面波转换,与采用传统的变换光学设计比较,基于阻抗可调变换光学理论的设计,数值模拟表明转换效率可提高约百分之六。     

微波六端口反射计仿真设计

六端口反射计在微波阻抗与网络参量测量方面有着很重要的地位。该文介绍了一个工作于要求频段（9—10GHz）内的六端口反射计的设计方案，通过对反射计的S参数进行分析确立设计指标；依据这一指标，该文首先通过LSBRM方法确定波导网络的内半径及中心金属轴半径；进而采用频移法来确定渐变线的大端的高度；最后用渐变线分割的方法和数值积分的算法确定了波导渐变线的长度L，完成方案的设计；对设计好的反射计经测量检验，该反射计在9—10GHz频带内的最小衰减可达到-20dB，满足设计指标的要求。该文提供的方法，同样适用于其他频段内工作的反射计的设计，对相关科研工作人员具有一定的参考价值。     

A micro-array bio detection system based on a GMR sensor with 50-ppm sensitivity

Bio detection is widely utilized in hospitals and laboratories. However, conventional bio detection methods suffer from long detection time, complex operation, and low sensitivity, and these issues prevent their use in point of care testing (POCT) applications. Microelectronic bio detection methods are proposed to overcome these issues. Bio detection based on a micro-electronic technique allows easy integration of a system, leading to a fast detection speed and simple operation. In this work, a fully microelectronic bio detection system including a sensor design, a read-out strategy, and data processing is proposed based on a GMR biosensor. A GMR sensor chip is designed and different passivation layer thicknesses are tested to improve sensitivity. A 40 nm thickness passivation is realized to produce the largest response without oxidization and breakdown. In order to integrate the read-out circuit and simplify operations, a 4-channel read-out biochip is designed and fabricated, and this exhibits a super-low output noise corresponding to ?116.84 dBm/Hz at the operation frequency. This means that the noise only approximately corresponds to the signal level of five magnetic nanoparticles with a diameter of 200 nm. A reference sensor is also utilized to cancel the unwanted signal and reduce common-mode noise and error to improve sensitivity. Measurements indicate that 90% suppression is achieved. The measurements also reveal that a sensitivity of 50 ppm is achieved with the proposed GMR bio detection system.     

Hysteresis compensation in a magnetostrictive linear position sensor

A new linear position sensor (Micrus) has been developed, based on the transmission of ultrasonic signals in a waveguide. Waves are generated at the cursor position by the magnetostrictive effect, and their times of flight to the ends of the waveguide are used to estimate the position of the mobile element. The choice of the generating/transmitting metal for this kind of sensor is discussed. We have found that the magnetic hysteresis inherent to the magnetostrictive phenomenon translates into measurement hysteresis, affecting the performance of the sensor. An explanation of the link between both effects is given, and a compensation technique based in focusing the ultrasonic generation is offered. This compensation technique is tested using an electromagnetic finite element method program and then empirically in the Micrus sensor, with satisfactory results.     

Local observability and controllability of stirred tank reactors

This paper deals with the observability and controllability properties of the linearized tangent dynamic model of (bio)chemical processes in isothermal stirred tank reactors (STRs). It is shown that a necessary condition for the observability (controllability) of isothermal (bio)chemical processes is that the number of measured components (the number of control inputs) is larger than or equal to the number of process components minus the number of reactions involved in the process. This gives a simple test for detecting possible lack of observability and/or controllability of isothermal STRs.     

光波导化学传感器的数据采集和分析软件的开发

在光波导化学传感器研究中,辐照计检测的光强度由记录器(打印机)显示。对观察、记录、分析和保存检测的数据极不方便。因此提高和改进光波导检测系统的性能,用VB6.0编程语言开发数据采集和分析软件。通过数据采集卡将辐照计连接计算机并用该软件记录、处理、分析和保存检测数据,一整套实时图形化显示过程。本论文详细介绍检测系统的硬件、软件结构和性能,它不需要任何应用软件支持,可以在Windows中直接运行,界面友好、操作方便、运行稳定性好。计算机采集和处理检测数据使新系统在灵敏度、可靠性、响应速度和检测数据的精密度等方面超过了原来系统的性能,并为检测、研究该类传感器在智能化方面提供指导作用。     

The application of a light guiding flexible tubular waveguide in evanescent wave absorption optical sensing

A light guiding flexible fused silica (FFS) capillary has been used in designing evanescent wave (EW) absorption based chemical sensors. The FFS capillary is similar to a conventional silica optical fiber in that it can guide light in the wavelength region from UV to near infrared, but different from a conventional optical fiber in that it is a tubular waveguide. The inner surface of the FFS capillary is fused silica, which was coated with a reagent doped polymer in order to design an optical fiber chemical sensor. The FFS capillary has a cladding layer plus a protection polymer coating on its outside surface. The cladding layer ensured the capability of the FFS capillary for guiding light. The protection coating increases the FFS capillary's mechanical strength and makes it robust in practical applications. This makes the FFS capillary very useful in designing an EW based optical chemical sensor of a long path length. Techniques for activating the inner surface of an FFS capillary, coating the inner surface of the capillary with a polymer, connecting the coated capillary to a light source and a photodetector, and delivering a sample through the capillary have been developed in this work. Three optical sensors for sensing Cu(II), toluene in water samples and ammonia in a gas sample have been fabricated and tested. Preliminary test results obtained in this work illustrate the feasibility of fabricating highly sensitive EW absorption based chemical sensors with the light guiding FFS capillary.     

抗共振反射集成光学传感器的研究进展

抗共振反射光波导(ARROW)具有与传统光波导所不同的传播特性。利用覆盖层的抗共振反射性质,ARROW传播单模、高阶模被泄漏到基体。基于折射率的变化,抗共振反射传感器对物理量、化学量和生物分子间的相互作用有很高的敏感性。介绍了ARROW的结构、传感器的工作原理以及最新研究进展。由于可采用CMOS工艺制作波导,且能与光探测器在一块集成,抗共振反射传感器将具有广阔的应用前景。     

光波导加速度传感器中3dB耦合器设计

光波导加速度传感器是一种实用型加速度传感器,目前广泛应用制备光学加速度计的迈克尔逊、马赫—曾德等干涉仪的核心部件都包含3 dB耦合器。3 dB耦合器的设计对光波导加速度传感器的检测精度尤为重要。介绍了所设计的光波导加速度传感器的工作原理,设计了3 dB耦合器波导的结构和参数,并用光学模拟软件OptiBPM对3 dB耦合器进行模拟。结果表明:所设计的3dB耦合器具有良好性能,符合设计要求。     

Wideband turnstile junction coaxial waveguide orthomode transducer

A wideband turnstile junction coaxial waveguide orthomode transducer (OMT) is presented in this paper, featuring coaxial waveguide input and orthogonal rectangular waveguide outputs. It primarily comprises of a turnstile junction, bending stepped impedance transformers and power combiners. The symmetrical geometry helps achieve wide operating bandwidth and balanced output phases. The OMT covers the whole Ku band from 12 to 18 GHz, which aims at wideband dual‐polarized signal combination and separation within coaxial‐type multi‐band antenna systems. An experimental prototype is manufactured and the measured results confirm that the reflection coefficient is lower than ?15 dB within the whole band, and the port isolation is better than 35 dB. Turnstile junction coaxial waveguide OMTs can be adopted widely in circular/coaxial waveguide hybrid feeding networks for multi‐band satellite communication/remote sensing antenna systems.     

基于基片集成波导和消逝模谐振腔的压力传感器设计

提出一种新型的基于基片集成波导和消失模谐振腔的压力传感结构。设计了圆形空腔,当施加外界压力时,圆形空腔发生形变从而使谐振腔谐振频率变化。采用共面波导线对谐振腔进行耦合馈电并将频率信号传输出来。通过读取传感器的回波损耗参数( S11)来表征压力与频率的关系。利用高频仿真软件HFSS对谐振腔进行了仿真设计和优化,设计尺寸为30 mm×30 mm×1.93 mm,与传统谐振腔相比体积明显减小。传感器基底为Rogers 4003C板材,采用PCB技术进行加工。搭建压力测试平台对传感器进行测试,结果表明在0~3 N的压力范围内变化100 MHz,绝对灵敏度为25 MHz/N。仿真和实测结果比较吻合,验证了所设计压力结构的有效性。     

基于改进BP神经网络的菌体浓度软测量

提出一种改进的BP神经网络(IBPNN)用以建立发酵过程中菌体浓度软测量模型.结合菌体浓度变化范围大这一特点,将传统BP网络的误差函数进行了改进,并利用最优停止法对网络进行训练.避免了过拟合现象.最后针对诺西肽发酵过程中茵体浓度的估计问题,根据隐函数定理选取辅助变量,应用IBPNN建立菌体浓度软测量模型,实验结果验证了所提方法的有效性.     

A microfluidic sensor based on ferromagnetic resonance induced in magnetic bead labels

This report details preliminary studies towards the development of a microfluidic sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal transduction. The device consists of a microwave circuit in which a slotline and a coplanar waveguide are integrated with a biochemically activated sensor area. The magnetic beads are immobilized in the sensor area by bio-specific reactions. A microwave signal applied to the slotline is coupled to the coplanar waveguide only in the presence of magnetic beads at the functionalized sensor area. Ferromagnetic resonance in the beads further enhances the coupling. This inductive detection technique lends itself to miniaturization, is inexpensive to fabricate and can be adapted for the detection of a wide range of molecules for which bio-specific ligands are available.Experimentally, the variation of the output signal as a function of the location of magnetic beads was studied for the proposed technique. Subsequently, a prototype device was constructed by biotinylation of the sensor area and integration with a microfluidic chip fabricated in polydimethyl siloxane (PDMS). Preliminary experiments were conducted on this prototype using streptavidin-functionalized magnetic beads as labels. It was shown that the magnetic beads, immobilized at the sensor area by streptavidin-biotin linkage, produced a distinct ferromagnetic resonance response easily discernable from the background signal.