基于特殊激光微造型工艺的控制方法研究

鉴于激光表面微造型技术加工金属材料时会带来较严重的负面热效应,提出"单脉冲同点间隔多次"的激光微造型新方法.通过对运动控制卡与自制的调Q控制卡的软件编程,利用声光调Q技术及伺服控制,完成了运动控制系统与激光系统的协同控制,从而实现激光加工新方法.整个系统通过工控机集中控制,利用该方法能够高效率加工出微观或宏观的造型形貌,且能显著减少激光加工所带来的热效应负面影响.该控制系统可在摩擦副表面加工出优化设计的微观形貌.经实际加工验证,设备能够满足加工要求且能获得较好的微观形貌和表面质量.     

全塑料光学生命探测仪关键技术研究

制作了单丝直径为250 μm、像素数为4096、长度为15 m的塑料光纤传像束. 研究表明: 原始图像经过该15 m长的光纤传像束后, 仍有25%保留, 完全可以满足图像目视观察或CCD图像采集的需要. 以此光纤传像束为核心部件, 分别设计、制作了目视式生命探测仪样机, 以及与CCD、图像采集卡、笔记本电脑一体化的智能型光学生命探测仪样机. 最后, 演示了该系统对被困人员搜救的有效性. 此系统不但可用于地震、矿难等场合被埋人员的搜索, 也可用于高压强电磁干扰环境、保密部门、易燃易爆等特殊场合的视频监视.     

一种金融双界面卡可测试性设计研究

由于安全性好,存储容量大等方面的优点,金融IC卡代替传统的磁条卡已经成为一种必然趋势。由于电路的复杂性,在金融卡的设计过程中必需注意可测试性设计。论文对一种金融双界面卡进行可测试性设计,主要关注嵌入式存储器、振荡器电路和非接触模拟前端电路的可测试性设计,在进行理论分析的基础上提出测试结构,并对电路进行设计。最终基于V777系统对流片以后的金融双界面卡进行测试,测试结果表明本设计具有很好的功能。     

A low cost PC based card for heat-capacity measurements at low temperatures

We describe a simple, low cost pc based card for the measurement of heat capacity using adiabatic calorimetry at low temperatures. This card provides the control pulse to the sample heater as well as trigger pulse to the nano-voltmeter which monitors the sensor voltage (Ge sensor, Lake Shore Inc., USA). We have also added a 12 bit DAC on this card and this is used for remote setting of the heater current of an old SHE (now Biomagnetic, Inc., USA, model CCS) analog constant current source. Although this card is used here for heat-capacity measurements, the same can also be used for thermo-power and thermal-conductivity measurements.     

具有混音功能的新型语音卡设计与实现

为满足某控制系统实时记录语音和播放录音的实际需求,基于语音压缩编码技术,以现场可编程门阵列(FPGA)为控制核心,设计实现了16个通道采集语音信号,进行ADPCM编码,将语音文件以WAVE格式存储,集监听、播放指定语音通道及任意时间段录音于一体的紧凑型PCI(CPCI)板卡。该板卡区别于传统语音卡的创新点在于运用语音叠加技术使板卡具有混音功能,能够将不同通道语音混音、记录存储,同时具有压缩比可自由选择的功能。详细介绍了板卡的组成机构、工作原理、硬件设计和软件设计。最后进行实验测试,板卡语音存储、语音回放等各项功能正常,音质良好,验证了设计方案的可行性与实用性。     

波导多层光卡数据页的图像截取算法研究

提出了一种基于波导多层光卡数据页图像的截取算法,以解决准确读取光卡信息和最终译码的关键问题。该算法是在一个预处理的二值化图像基础上,依据梳状图的统计特性和数据页的图像纹理特征,对一个完整数据页的起始坐标和长宽进行估算,达到对光卡数据页的图像截取的目的。最后通过具体实例验证了基于波导多层光卡数据页的图像截取算法的有效性。     

MCNP程序中一处缺陷的证实及规避方法北大核心CSCD

当应用MCNP程序的SDEF卡进行固定源问题的源信息描述时,需要对源的分布进行描述,MCNP程序提供了SP卡用以指定源在各个栅元中的分布概率,SP卡中的V选项用于便利用户实现体密度方式的源强分布描述。研究发现,该程序存在一个缺陷,在使用SP卡V选项时可能会导致计算结果的不准确。通过构建典型算例模型,对使用V选项和不使用该选项的计算结果进行对比分析,可以证实该缺陷的存在,并且能够证明可以通过其他源描述方法在具体的程序使用中规避该缺陷。     

基于PCIe总线接口的EtherCAT从站网卡设计

在基于EtherCAT总线的集散式数据采集系统中,针对测量仪器的高速实时采集需求,设计了一款基于PCIe接口的EtherCAT从站网卡。该网卡将不含网络接口的工控机直接接入EtherCAT网络,从而为浪高、流速、浮体六自由度等物理量的高速实时采集提供了一种简便灵活的实现途径。文中首先介绍了从站网卡的总体结构,接着从硬件和软件两部分详细给出了从站网卡的设计思路,最后通过实验验证了所提方案的有效性。试验结果表明,该从站网卡完全满足对数据传输的实时性、同步性、速度和准确性的要求。     

Magneto-optical imaging using a garnet indicator film prepared on glass substrates

We observed the magnetic domains of a magnetic card by using the bismuth-substituted yttrium iron garnet (Bi-YIG; Bi₁Y₂Fe₅O₁₂) thin films as the indicator films. The magnetic domains’ dependence on the preparation conditions of the garnet thin film crystals was visualized by using a magneto-optical microscope. Garnet thin films were fabricated on glass substrates using a metal-organic decomposition method (MOD). We found that bigger Faraday rotation was measured in the better crystallized indicator films. Polycrystalline Bi-YIG thin films were successfully obtained for the annealing temperature of 700 °C and an annealing time of 1 h. The thickness of the film was about 47 nm for a single coating during the MOD process. The Faraday-rotation angle of the films was estimated as −2.47°/μm and the angle was comparable to other synthesis methods, such as the sol-gel and the RF-magnetron sputtering. Using these indicator films, we could image the magnetic domains of magnetic materials.     

高能X射线工业CT扫描运动控制系统设计

 分析了高能X射线工业CT扫描运动控制系统的作用,提出了扫描运动控制系统的组成方案。控制系统由工业控制计算机、计数卡、控制卡、伺服驱动器、伺服电机、工作平台、光栅和控制软件组成。研究了在Windows驱动程序模式（WDM）下,控制系统设备驱动程序的组成。以运动控制卡为例,研究了开发控制系统设备驱动程序的方法,并分析了设备驱动程序和用户程序交互的过程。通过编写WDM驱动程序,实现了对高能X射线工业CT扫描运动系统的实时控制。实验结果表明,开发的扫描运动控制系统,可靠性和实时性满足要求。     

基于RTX实时系统ARINC429总线通信驱动开发

某型导弹模拟器采用ARINC429总线通信,根据通信协议的实时性要求,通信板卡需要运行在实时环境中,因此设计并实现基于RTX实时环境下PCI插槽的ARINC429总线驱动。在简要介绍ARINC429通信板卡和RTX实时子系统的基础上,将硬件板卡从Windows环境下转换到RTX环境,详细介绍了驱动系统结构以及标准驱动的实现步骤和关键技术,并通过实验测试证明,该驱动程序能够准确可靠实现总线数据的接收和发送,且实时性良好。     

A prototype scalable readout system for micro-pattern gas detectors

A scalable readout system(SRS) is designed to provide a general solution for different micro-pattern gas detectors in various applications.The system mainly consists of three kinds of modules:the ASIC card,the adapter card and the front-end card(FEC).The ASIC cards,mounted with particular ASIC chips,are designed for receiving detector signals.The adapter card is in charge of digitizing the output signals from several ASIC cards.The PEC,edged-mounted with the adapter,has field-programmable gate array(FPGA)-based reconfigurable logic and I/O interfaces,allowing users to choose different ASIC cards and adapters for different experiments,which expands the system to various applications.The FEC transfers data through Gigabit Ethernet protocol realized by a TCP processor(SiTCP) IP core in FPGA.By assembling a flexible number of FECs in parallel through Gigabit Ethernet,the readout system can be tailored to specific sizes to adapt to the experiment scales and readout requirements.In this paper,two kinds of multi-channel ASIC chip,VA140 and AGET,are applied to verify the scalability of this SRS architecture.Based on this VA140 or AGET SRS,one FEC covers 8 ASIC(VA140) cards handling 512 detector channels,or 4 ASIC(AGET) cards handling 256 detector channels,respectively.More FECs can be assembled in crates to handle thousands of detector channels.     

Data acquisition card for varian electron paramagnetic resonance spectrometers

An easy to assemble and inexpensive PC card that interfaces E-Line Varian spectrometers (E-6, E-9, E-12 and E-15) with IBM compatible PCs is presented. The card has a Programmable Interval Timer so it does not need an external clock making it instrument independent. The accessory contains its own RAM. This allows the device to store the spectrum while sampling is in progress, so the PC can meanwhile be used for any other task.     

基于FPGA的红外图像仿真注入系统

设计了一种新的图像注入系统来实现PC机仿真图像到红外处理系统的直接传输。首先,该系统利用USB2.0接收PC机对外场实测数据仿真得到的BMP格式文件,用FPGA控制由两个SDRAM组成的缓冲模块进行图像缓存,然后通过Camera Link接口传送出去。系统数据缓存采用乒乓操作,避免了数据处理时无法持续接收而丢失有效数据的现象。测试时用图像采集卡进行图像采集并显示。结果表明,该系统具有速度快、实时性好、稳定性高等特点,可替代光电跟瞄设备进行仿真训练及设备的动态检验。     

在体剂量检测专用EPR数据采集与控制系统

研制了X波段在体剂量检测专用EPR谱仪的数据采集与控制系统,利用阿尔泰USB2812数据采集卡作为控制卡,在LabVIEW图形化编程开发环境中进行程序开发,实现了扫场电源的控制、微波模的显示、微波功率的控制和EPR信号的采集等功能. 数据处理程序可实现存储数据的查询、谱线基线校正和积分等基本功能,为下一步开展牙齿剂量试验研究提供了平台.     

Design and implementation of fuzzy logic based automatic gain controller for EDFAs

In this study, the design and implementation of a fuzzy logic (FL) based automatic gain controller card (AGC) is performed in order to control the pump laser current with respect to signal power and signal wavelength. The FL-AGC card consists of an amplifier, an analogue to digital converter (ADC), a digital to analogue converter (DAC), and a FL based software that is embedded to a microcontroller. With this configuration, gain flattening at the output of the erbium doped fibre amplifier (EDFA) along C band is achieved. In this way, ergonomically designed FL-AGC card can be easily matched with EDFAs and can be applicable to optical system applications.     

中子发生器束流传输光学系统研究及模拟计算

 束流传输系统是中子发生器研制、调试和技改等工作顺利进行的重要依据。为此开展了中子发生器束流传输系统研究工作,阐述了传输系统光学特性和组成。以ns-200中子发生器为代表实例,详尽地分析了传输系统的组成和各光学透镜的特性。根据LEADS软件要求,生成该器束流传输系统数据输入卡,调用软件相应各光学元件计算模块,进行了模拟计算,给出了束流传输包络图。束流传输模拟计算结果与原设计要求基本一致。     

基于LabVIEW和声卡的音频信号采集与分析系统设计

详细介绍了系统的开发背景,软件结构和特点,系统地分析了数据采集硬件和软件设计技术,在此基础上以声卡为数据采集卡,以LabVIEW为开发平台设计了音频信号采集与分析系统。这种系统具有界面友好,维护简单等优点。系统不但可以实现对音频信号进行采集,还可以对采集的信号进行分析和保存。可以根据需要改变系统的功能,具有很好的教学实...     

基于Lab VIEW的半导体光源P-I特性测试系统

采用PCI-6251数据采集卡和LahVIEW平台。设计了一套半导体光源的P-I特性测试系统。该系统通过软件驱动数据采集卡为发光器件提供合适的驱动电压,采集发光器件的光功率和驱动电流,实现了P-I特性曲线的测量、分析和存储等功能。测试结果表明该系统设计成本低、测量效率高、人机界面友好、操作简单、扩展性强,适用于教学、实验及科研等领域。     

Parity and ruin in a stochastic game

We study an elementary two-player card game where in each round players compare cards and the holder of the card with the smaller value wins. Using the rate equations approach, we treat the stochastic version of the game in which cards are drawn randomly. We obtain an exact solution for arbitrary initial conditions. In general, the game approaches a steady state where the card value densities of the two players are proportional to each other. The leading small value behavior of the initial densities determines the corresponding proportionality constant, while the next correction governs the asymptotic time dependence. The relaxation toward the steady state exhibits a rich behavior, e.g., it may be algebraically slow or exponentially fast. Moreover, in ruin situations where one player eventually wins all cards, the game may even end in a finite time. Received 24 August 2001 and Received in final form 12 November 2001