一种脑电地形图快速成像方法研究

脑电地形图是一种脑电信号成像的重要技术。结合临床应用的需要,文章提出了一种脑电地形图的快速成像方法,包括脑电地形图的成像原理、数据平均功率谱计算、大脑平均功率谱密度分布模型的构建方法以及图案快速填充算法的原理及编码实现。     

脑电控制及检测设备的研究与实现

通过分析脑电信号与人体精神状态的关系以及脑电检测方法,设计相应电路对脑电信号采集并进行分析,重点对从脑电信号中解析出的人体精神专注度的数据进行研究和应用,设计出可以采集脑电信号,测试者通过调节注意力,用注意力的集中程度来改变彩灯颜色变化的脑电检测设备,进行脑-机交互操作.     

脑电信号反馈控制装置的设计

本文研究设计了专用于治疗神经系统脑部疾病的智能化离电信号反馈控制装置。在分析人体脑电信号的基础上，将脑电生物反馈与电磁反馈有机结合，能有效地调节脑神经细胞的电活动。临床研究表明，该装置对神经系统一些脑部疾病有显著疗效。     

边缘学科分支最新动向

TN一051 2005021617 荃于小波包分解的精神分裂症脑电信号分析/许慰玲,黄静霞,沈民奋 (汕头大学)11电子测量与仪器学报.一2004,1s(2)一35一40 文中针对脑电信号的非平稳性,引入小波包分解理论研究精神分裂症脑 电.根据脑电信号的不同节律特性,提出应用小波包分解构造不同频率 特性的滤波器,提取脑电信号不同节律的动态特性,并由此构造各种节 律的动态脑电地形图.为了研究精神分裂症脑电信号各种节律的动态特 性,文中对正常人和精神分裂症病人的临床脑电数据进行分析与比较, 分析两组脑电信号各种节律的动态特性.实验结果表明,精神分裂症病 …     

基于互样本熵的脑电功能网络构建及其应用

近年来,通过建立脑网络模型探索大脑功能、理解脑疾病的发生机理成为神经科学的研究热点。提出一种新的脑电网络地形图的构建方法,并探讨了其应用。首先对原始脑电信号进行截取,再对得到的时间序列进行小波包变换,实现原始信号的频率域分解;计算每个通道两两之间的互样本熵值,最后通过拓扑作图得到基于互样本熵的脑电网络地形图。研究表明,所提出的网络构建方法一定程度上能够反映不同的脑功能状态,对于分析理解大脑功能状态、诊断临床脑部疾病可能提供一种新的有效方法。     

基于头皮脑电的游戏型脑机接口应用研究综述

游戏型脑机接口(game-BCI)是指将脑机接口与游戏结合,通过对脑电信号的识别,使用户完成对游戏的直接控制,不仅为健康人提供了新型的游戏交互方式,也为残障人士提供了新的康复治疗途径.相比于其它侵入性BCI,基于头皮脑电的BCI有无创、时间分辨率高、成本低、便携性好等优势,具有更加广泛的应用前景.该文对基于头皮脑电的游...     

通用串行总线脑电信号采集电路设计

脑电信号的准确采集对于研究人脑活动、诊断疾病至关重要.针对脑电信号的特征,设计出使用16路电极提取脑电信号,采用高精度仪用放大器实现三级放大,设计有源双T陷波电路来抑制50 Hz工频干扰,设计光电隔离电路和16住A/D转换电路及USB接口电路.该电路实现了脑电数据的准确采集、高速传输和实时处理,有效解决了传统脑电数据采集系统速度慢,处理功能简单,数据存储量小,连接复杂等缺陷,满足了实际需要.     

脑电信号中眼电伪迹自动去除方法的研究

 针对实际采集的脑电信号受眼电干扰较大,提出一种基于离散小波变换(DWT)与独立分量分析(ICA)的自动去除眼电伪迹的方法(DWICA).对采集的多导脑电和眼电信号进行离散小波变换,获取多尺度小波系数,将串接小波系数作为ICA的输入;利用基于负熵判据的FastICA算法实现独立成分的快速获取,引入夹角余弦准则自动识别眼迹成分,并经过ICA逆变换将剔除眼迹后的独立成分投影返回到原脑电信号各个电极;通过DWT逆变换重构信号,即可得到去除眼迹的各导脑电信号.实验结果表明,DWICA方法极大地提高了脑电信号的信噪比,抗噪能力强且实时性好,为脑电信号的在线预处理提供了新思路.     

边缘学科分支最新动向

TN一051 98031441非周期波谱分析方法在脑电效应测定中的应用/卢建丰,杨友春,陈刚,相秉仁,安登魁(南京军区总医院)I北京生物医学工程一2997,16(4)一223~227目的:应用非周期波谱分析技术对受试者用药后的原始脑电信号进行分析.方法:采用寻找脑电波峰、谷的技术,对每秒内脑电波峰或谷的数目以及每个峰的电压进行计算,并将o”30H:的脑电波分成四个波段.结果:发现。~3H:、4、7H:、s~nHz每秒脑电波数或电压并无规律性变化,12~30H:每秒电压或波数呈现明显的规律性变化,并与浓度具有良好的相关性。结论:可以应用非周期波谱分析技术获得反映药物…     

基于 FPGA 的多路微弱医学生物电信号处理系统

介绍了一种便携式多路微弱医学生物电信号处理系统,用户可根据实际的需要对电极进行选择,从而实现对脑电或心电信号的实时采集,进而对其进行数据处理并显示波形和存储数据。该系统采用德州仪器(TI)公司的ADS1198为核心的模拟前端电路实现脑电或心电信号的采集、放大、隔离等预处理操作,利用Altera公司的FPGA芯片Cyclone Ⅱ EP2C70F896C6对数据进行处理,并在TRDB_LTM液晶屏上显示波形。该系统精度高、体积小、功耗低,具有较好的实用性和可扩展性。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.