nA量级微电流测试仪的研发

光传感器是利用光敏元件将光信号转换为电信号的传感器，它的敏感波长在可见光波长附近，包括红外线波长和紫外线波长。光传感器不只局限于对光的探测，它还可以作为探测元件组成其它传感器，对许多非电量进行检测，只要将这些非电量转换为光信号的变化即可。光传感器是目前产量最多、应用最广的传感器之一，它在自动控制和非电量电测技术中占有非常重要的地位．     

基于符号化部分互信息熵的多参数生物电信号的耦合分析

提出了一种新的时间序列耦合信息分析方法–-基于部分互信息符号化部分互信息熵. 研究表明, 多参量的生物电信号各参量间具有耦合关系, 使用符号化的部分互信息能够很好地对生物电信号时间序列进行分析, 从而获得其耦合程度.应用该算法对生物电信号计算并进行假设检验, 结果表明清醒期的生物电信号耦合程度显著高于睡眠期, 证明符号化部分互信息可以用来分析时间序列间的耦合信息, 而且生物电信号的耦合程度可以作为度量一个物理过程是否处于活跃状态的参数, 未来可以应用于临床医学以及生物电传感器等领域. 关键词： 符号化 部分互信息熵 生物电信号 耦合     

仿生生物感官的感存算一体化系统

生物感官集感知、存储与运算为一体的架构使其可以高效并且实时地采集和处理外界信息,这样的感存算一体化架构可为物联网时代面临的传感器数据爆炸问题提供很好的解决方案.为此,本文提出仿生生物感官的感存算一体化系统,采用不同的传感器模拟生物感受器的功能,以获取环境信息,传感器输出的模拟信号输入到模拟信号处理系统进行预处理,这样信号不需要在模拟域与数字域之间转换,可极大降低功耗和延时;预处理后的信号输入类脑运算芯片中进行分析和决策,该芯片由基于忆阻器的人工突触及人工神经元组成,通过控制突触与神经元的连接方式,可以实现不同的算法架构,如全连接脉冲神经网络、卷积脉冲神经网络以及循环脉冲神经网络等;通过运行不同的神经网络,类脑运算芯片可以实现对不同传感器信号的识别、预测以及分类等任务;更进一步,将多种仿生感觉系统的识别或预测结果结合起来,就可以实现多感官融合,这样的系统架构可以用于自动驾驶及智能机器人等复杂的场景中.     

使用载荷传感器测量液体密度

载荷传感器用于液体密度测量,可将力信号通过传感器转化为电信号,经过运放由数字电压表显示密度值,实现了液体密度的实时测量.     

基于回音壁谐振模的无标记光学生物传感技术

光学生物传感器在新药研制和生命科学等领域得到广泛关注,重点对基于回音壁谐振模的无标记光学生物传感器做了评述。根据谐振腔结构将传感器分为三类。基于微球的生物传感器由于微球腔的高品质因子而成为最初研究的重点,已实验研究了对蛋白质分子、病毒和细菌的传感响应,建立了基于单光子谐振能量和微扰理论的理论模型;基于微盘的生物传感器能够利用成熟的平面光刻微加工技术,传感构想提出更早,但直到回流热处理技术的应用才使得微盘品质因子大幅提高,从而实现了单分子测量;基于微环的生物传感器具有简单的谐振模式,有利于信号探测,已采用聚合物,氮化硅,以及硅基二氧化硅等材料制作成功,作为其在三维上的扩展,微管式传感器由于能够将光通道和流体通道合二为一而在近年得到关注。     

光电化学生物传感器研究

光电化学法是在光照射下,将化学能转换为电能的低成本方法。而光电化学生物传感技术由于具有通过生物分子氧化产生的光电流来检测生物分子的能力而引起了广泛的关注。光电化学生物传感器具有低成本、高灵敏度、高特异性、仪器操作简单以及检测背景信号低等特点,在免疫检测和生物技术等重要领域具有广泛应用前景。近年来,对于光电化学生物传感器性能和检测方法的研究也取得了颇丰的成果。本文主要介绍光电化学生物传感器的概念及基本原理、分类应用及对其未来的展望。     

基于LabVIEW的电流信号采集系统的设计和实现

在机电设备、精密器件等研发工作和电路校准、传感器应用等日常实验中,数字多用表常被用于微弱信号的测量,但数字多用表只能实时显示采集到的信号,不能存储信号,在实验和应用中无法将检测到的波形、数据和实验状态实时对应,只能通过人工肉眼估计读取,给实验和应用带来了一定的困扰。为了解决该问题,开发了一个基于LabVIEW的电流信号采集系统,该系统可以将采集到的波形实时显示在面板上,同时将检测到的准确电流数据和读取时间存储到PC机。实验结果表明,该系统可以更好地显示电流信号,同时可以进行信号的存储,避免了肉眼读取数字多用表的误差,增强了读取数据的准确性。     

基于渐进圆锥天线的ns前沿电磁脉冲电场传感器

为了对ns级上升沿的电磁脉冲电场进行测量,研制了一种基于D-dot渐进圆锥天线的电场传感器。设计采用单极子渐进圆锥天线作为电场传感器的接收天线,并通过建模仿真验证了该天线的性能;通过电光转换模块将天线感应的电信号转换为光强度信号并通过光纤传输;利用软件积分对传感器测得的电场微分信号进行处理;通过测试试验验证了传感器的性能。研究表明,所研制的电场传感器能够测量上升沿大于1.5ns的脉冲电场,具有体积小、线性度高的优点。     

太赫兹超材料生物传感器的应用研究进展

太赫兹（THz）波,是指频率范围在0.1～10 THz的电磁波,在电磁波谱中处于红外与微波之间。太赫兹波的光子能量相对于可见光更低,1 THz对应的能量大约只有4.14 meV,意味着这将大大减少对生物体内组织器官的辐射而引起的伤害,不会对生物分子产生电离。因此,该波段在基础科学、人体安检、危险品检测、高速通信和医学成像等领域具有重要的潜在应用价值。但在医药和生物探测的应用中,通常需要检测微量的分析物,这就需要更高的灵敏度和检测的准确度。但是现存的检测方法受到太赫兹波强度检测可靠性不高的影响。基于超材料的生物传感可以通过增强局域电磁谐振,实现亚波长分辨,大大提高了传感器的分辨率与灵敏度,引起了人们的广泛关注。超材料是一种人工设计的周期性结构,通过合理设计可以增强局域电磁谐振响应,实现亚波长分辨,大大提高传感器的分辨率与灵敏度。太赫兹超材料传感器为生物传感领域提供了一种新的检测方法,具有灵敏度高、响应速度快、无标记检测等优点。随着微纳加工技术的快速发展,制作超材料太赫兹传感器的成本不断降低,从而在生物医学领域具有非常大的潜在应用价值。基于超材料的太赫兹传感器的研究已成为目前一个非常热门的国际前沿方向。但是关于太赫兹超材料传感器的最新研究进展未见报道,为此通过大量搜集并整理相关资料,综述了太赫兹超材料传感器在各种生物探测场景中的最新应用,分别从医学诊断、食品安全、农药检测等方面展开介绍。最后,对太赫兹超材料在生物传感器的发展和应用前景进行了总结和展望。该研究将为人们充分掌握太赫兹超材料生物传感器的最新应用进展提供重要参考,同时为太赫兹超材料传感器的发展和应用提供方向性的指导。     

柔性神经形态晶体管及其仿生感知应用

生物感知系统具有高并行、高容错、自适应和低功耗等独特优点.采用神经形态器件实现生物感知功能的仿生,在脑机接口、智能感知、生物假体等领域具有重大应用前景.与其他神经形态器件相比,多端口神经形态晶体管不仅可以同时实现信号的传输和训练学习,还可以对多路信号进行非线性的时空整合与协同调控.然而,传统刚性神经形态晶体管很难实现弯曲变形以及和人体密切贴合,限制了神经形态器件应用范围.所以,具有良好弯曲特性的柔性神经形态晶体管的研究成为了最近的研究重点.本文首先介绍了多种柔性神经形态晶体管的研究进展,包括器件结构、工作原理和基本功能;另外,本文还将介绍上述柔性神经形态晶体管在仿生感知领域中的应用;最后给出上述研究领域的总结和简单展望.     

Biomolecules for development of biosensors and their applications

Biosensors are analytical devices incorporating biological materials such as enzymes, tissues, microorganisms, antibodies, cell receptors or biologically derived materials or a biomimic component intimately associated with or integrated within a physicochemical transducer or transducing microsystem which may be either optical, electrochemical, thermometric, piezoelectric or magnetic. The electronic signals produced are proportional to the concentration of specific analyte. A biomaterial may be any material, natural or man-made, that comprises whole or part of a living structure or biomedical device, which performs natural function. An essential component of molecular sensor is reagent layers. Creation of these layers require the immobilization of recognition elements for the detection method. The recognition elements are biomolecules. Laboratory methods of immobilization are numerous, but may not always appropriate for manufacture of biosensors. In the present article, we describe the use of various biomaterials for biosensors as well as their availability.     

Genetically modified organism (GMO) detection by biosensor based on SWCNT material

This paper reports single-walled carbon nanotube-based biosensors for genetically modified organism (GMO) detection. Electrochemical electrode and single-walled carbon nanotube field effect transistor (SWCNT-FET)-based biosensors are used to determine the CaMV 35S promoter of Roundup Ready soybean. Given optimal conditions, both biosensors can effectively detect full complementarity with concentration as low as 1 nM. The sensitivity of the electrode-based biosensor is approximately 0.6 kΩ/nM while that of the SWCNT-FET-based biosensor is 0.32 nA/nM. Both biosensors were also used to determine a polymerase chain reaction-amplified sample. The obtained results showed that both sensors determined transgenic organisms well, thereby providing a useful tool for screening analysis of food samples.     

Some non-linear aspects of the electronic stages in time-domain modelling of NDE pulse-echo ultrasonic systems

Electronics interfacing with NDE probes frequently include non-linear switching devices and semiconductor networks, which influence the excitation pulses and detected echo signals. Classical approaches to modelling a pulse-echo process use ideal assumptions for the electronics and do not consider these influences on the echoes, which can be very relevant in HF cases. This paper proposes new ways to consider these non-linear effects in a time-domain simulation process, extending previous approaches by including new elements in the modelling. Specific electrical models covering the pulse-echo process are applied in the evaluation of echo-graphic signals. They include semiconductor devices and other non-ideal elements. From these models, and using SPICE as a simulation tool, strong non-linear effects on pulsed responses, computed for both E/R stages of typical NDE transceivers, are analysed.     

梯度折射率透镜在口腔内窥镜中的设计与应用

作为口腔内窥镜的摄像镜头，利用梯度折射率透镜质量轻、体积小、结构简单、分辨率高、成像景深大的优点，研制出一套适合医患交流及进行口腔检查与治疗的医疗装置。采用修正折射率剖面的梯度折射率透镜, 降低系统渐晕，减小畸变,获取口腔内部图像，经CCD光电转换装置转换成电信号，再将电信号经过数字信号处理以后，将该数字信息存储于计算机内部或在显示器上显示出来。口腔内窥镜是集梯度折射率透镜、光学原理、光学材料与加工、微电子、数字成像技术等为一体的新型医疗设备。特别是采用经修正的梯度折射率透镜制造的口腔内窥镜成像清晰, 在图像畸变、景深等方面优于现有产品，而且便于对患者的各种信息进行管理、查询、输出等。     

产生暗归零码光标记信号的新方案

在对预编码、调制和编码过程进行改进的基础上,提出了一种利用一个双臂马赫-曾德尔铌酸锂调制器和一个电信号时延器产生可调占空比和消光比的光暗脉冲归零码二进制信号的新方案。实验证明这种信号能用传统的二进制强度调制-直接检测系统的接收机进行检测。实验得到了在调节电信号时延器时速率为2.5 Gbit/s的光暗脉冲归零码二进制信号的频谱变化规律,以及占空比分别为0.25,0.35,0.60和0.80时光暗脉冲归零码二进制信号的误码率和眼图。此外,利用该方案产生的光暗脉冲归零码二进制信号可以作为标记在光标记交换网络中得到应用。     

傅里叶变换光谱分析系统及其测试

构建了一套改进的光的时间相干性以及傅里叶光谱分析实验系统,该系统利用光机电以及计算机软件编程技术,实时采集以He-Ne激光器、钠光灯和白炽灯为代表的各种光源在迈克耳孙干涉仪上产生的干涉条纹信号,将得到的光信号经光电倍增管转换为电信号进入电路系统,经滤波、A/D转换后,再输送到计算机进行傅里叶变换以及频谱分析.实验结果证实了该系统的有效性和实用性.     

Controlled synthesis and biomolecular probe application of gold nanoparticles

In addition to their optical properties, the ability of gold nanoparticles (Au NPs) to generate table immobilization of biomolecules, whilst retaining their bioactivities is a major advantage to apply them as biosensors. Optical biosensors using Au NPs are simple, fast and reliable and, recently, they have been moving from laboratory study to the point of practical use. The optical properties of Au NPs strongly depend on their size, shape, degree of aggregation and the functional groups on their surface. Rapid advances in the field of nanotechnology offer us a great opportunity to develop the controllable synthesis and modification of Au NPs as well as to study on their properties and applications. The size-controlled growth of Au NPs requires the isotropic growth on the surface of Au nuclei whereas anisotropic growth will induce the formation of Au NPs of varying shape. Functionalized Au NPs provide sensitive and selective biosensors for the detection of many targets, including metal ions, small organic compounds, protein, DNA, RNA and cell based on their optical, electrical or electrochemical signals. In this review, we will discuss the size- and shape-controlled growth and functionalization of Au NPs to obtain Au nanoprobes. The basis of the optical detection of Au nanoprobes and their applications in nucleic acid, protein detection and cell imaging are also introduced.     

基于AR模型与神经网络的核爆与闪电电磁脉冲信号识别

 对平稳随机信号功率谱估计的AR模型,分别利用自相关函数法和Burg算法求该模型系数,作为核爆炸和闪电电磁脉冲信号的特征值;采用BP神经网络作为分类器以及不同的隐含层数和隐含层节点数,对核爆和闪电电磁脉冲实测数据进行识别研究。结果表明：AR参数模型法对两类信号特征值提取是非常有效的,采用Burg算法来求AR模型参数,其特征值提取效果优于自相关函数法。     

Der Einflu\ unipolarer elektrischer Ladungen auf die Beweglichkeit von natürlichem Aerosol

The size distribution of natural occuring aerosol particles with radii from 10^?6 to 10^?5 cm was measured by investigation of the distribution of thoron decay products on the mobility spectrum. In addition we used an artifical ionization of the particles traversing a corona discharge. Thus the efficiency of the mobility spectrometer could be increased by a factor of four (as a function of corona current). The electrical charge distribution on the particles having passed the corona is out of equilibrium. Therefore the mobility spectrum can be reduced to a size spectrum only by means of an experimentally determined calibration function.     

Electrical coupling effects in an ultrasonic transducer array

Ultrasonic imaging devices often use transducer arrays for sampling the incoming acoustic field and converting it into electrical signals. After some convenient processing (amplification, dephasing, summing, etc), the electrical signals are used to modulate the brightness of a cathode ray tube (crt) monitor on which the ultrasonic image becomes visible. The quality of the imaging apparatus depends critically on the transducer array design and implementation.

Each individual transducer would, ideally, produce an electrical signal related exclusively to the ultrasonic field arriving at its surface; the reciprocal would also be true for transmission. In all practical cases, however, numerous effects lead to some coupling between nearby transducers, especially for very narrow transducers. The subsequent perturbations may be described as a narrowing of the radiation (or reception) pattern of the individual transducers, with respect to the theoretical predictions. To understand the mechanism for these couplings and to minimize them, their possible origins have been systematically studied. One of the most important sources of coupling is electrical leakage, which is reported here. Since no simple analytical calculation can be performed, diagrams have been established that enable evaluation of the electrical coupling against the dimensional characteristics of the array. Some means for reducing this coupling are suggested and comparative experimental results are given.