多晶体材料微观组织结构的计算机重构

介绍了用于多晶体材料微观组织结构重构的程序的算法.程序依据多晶体材料的电子背散射衍射(EBSD)分析所得数据,完成了多晶体材料微观组织结构的计算机重构,实现了多晶体材料微观组织的可视化,为采用数值化技术对多晶体材料微观组织结构进行定量分析创造了条件.     

椭球体三维数据场可视化模型及实现

分析了三维数据场可视化的典型应用及两类基本构造方法；提出一种椭球体三维数据场可视化模型，详细论述该模型的物理意义及实现算法，并给出利用该模型及其算法实现三维数据场可视化的实例。通过对效果图的分析表明，该方法所建立的三维图像具有良好的真实感，运行速度快且交互性能强。     

基于OpenGL的数控加工在线测量仿真技术研究

为了实现数控机床在线测量的可视化仿真,开发了一种用于数控机床在线测量的仿真软件。采用OpenGL作为图形系统开发环境;通过读取STL格式的零件模型文件,来显示零件的三维构造;通过解析含有理论点坐标的XML格式的测量指导文件,来显示被测点的理论位置;通过接收数控系统的测量数据,来实现在线测量系统测头的实时仿真。并使用CATIA生成的STL模型验证了该仿真系统的运行。     

城市地下管网三维可视化实现技术研究

通过分析三维管网可视化模型的实现方式,构建三维管网空间数据模型,选用Flt三维数据图形格式,提出了基于工程测绘数据、纸质蓝图和DXF格式CAD文件三种形式的三维管网模型自动构建技术;基于Vega Prime的场景漫游开发,可将地上建筑、地下岩层、管网等其它Flt模型引入到系统中,共同驱动,实现大场景城市地下管网的快速建模与三维可视化漫游。     

面向教学的三维变换算法可视化方法研究

在深入研究计算机图形学三维变换算法原理的基础上,分析了算法可视化的实质,建立了三维坐标系,并实现了坐标的投影变换,运用动态演示的方法,结合交互控制技术,实现了三维变换算法可视化教学演示系统CAI.学习者可以更快、更准确地理解计算机图形学三维变换的算法实质,有效地提高了教学质量.     

基于顶点索引的三维建模与可视化方法研究

分析了影响三维建模与可视化效率的主要因素,设计了一种新的基于顶点索引的三维模型数据组织方式,相对于传统的3DS模型文件,该方法避免了大量冗余数据的处理,并能充分发挥图形显卡高效的数据传输特性,经验证:显著提高了模型绘制的效率,较好地解决了复杂模型高效三维可视化的问题。     

NTFS系统存储介质上文件操作痕迹分析及数字取证技术算法实现初探

为了逃脱公安机关的打击,犯罪分子经常将计算机上的犯罪数据信息彻底删除,或将分区甚至整个硬盘进行格式化操作,从而使得重要的犯的罪证据丢失,给案件的取证带来极大的困难。因此,如何迅速准确的在计算机上恢复出犯罪证据,成为切实打击犯罪的一个关键因素。本文通过对NTFS文件系统结构的详细介绍,重点分析了NTFS文件系统的主文件表MFT、文件记录的结构和文件的几个关键属性（即文件名,标准信息,数据流等）,从计算机取证角度探讨NTFS文件系统下访问文件（夹）的方法,研究NTFS文件系统下文件和文件夹的操作痕迹,并在此基础上提出了一种基于NTFS文件系统的数据恢复算法。该算法通过分析NTFS文件系统的结构,将待取证的数据分为3类,采取不同的策略进行处理,通过数据恢复技术恢复被删除的数据并在此基础上实现计算机取证。     

稳瞄稳向系统可视化仿真平台研究

以防空作战条件下稳瞄稳向系统的研究需求为背景,为实现作战过程的三维一体化仿真,设计基于MFC框架的Open GL可视化仿真平台实现方案;建立稳瞄稳向系统可视化仿真平台所需的3D模型;通过模型格式转换与加载、模型位姿控制数据的读取,模拟防空作战条件下4个阶段的稳瞄稳向过程。通过与实测数据的连接表明:该可视化仿真平台可作为稳瞄稳向系统性能的验证平台,对系统性能进行直观的评判,具有一定的参考价值。     

三维数据场可视化的算法及实现

本文介绍了科学计算可视化的核心问题——三维数据场可视化(volu-me visualisation)的基本算法,并以CT扫描医学图像的三维重构及三维流场的可视化为例,讨论了绘制三维场的面表达及体直接表达算法的实现问题,文中还给出了算法实现中的实验结果。     

基于Web的飞机装配可视化系统研究

针对目前国内航空制造企业飞机装配生产中所存在的装配质量与效率偏低、生产管理水平不高等问题,面向装配车间实际生产过程,设计开发了基于B/S结构的飞机装配可视化系统。首先,构建车间单一产品数据源信息模型,为不同角色成员开发相应功能模块;然后,使用DELMIA仿真装配过程,输出可视化文件;其次,使用ActiveX技术实现装配动画页面内的三维交互。最后,以某型号大型飞机舱门作为对象,集成验证了该系统的可行性与实用性。     

采用图像格式的IDE硬盘直写记录

介绍一种采用IDE硬盘的高速图像记录系统的设计方法。该方法去掉了大量的软件编程代 之以硬盘直写图像文件的模式,将图像数据记录到硬盘的同时直接以文件形式存放。实验效果表明,采用该设计方法的记录设备做到了记录完全脱机,事后将硬盘通过USB接口直接与计算机相连,即可对图像进行访问,达到了预期的目的。     

Geometrical analysis of woven fabric microstructure based on micron-resolution computed tomography data

The global mechanical properties of textiles such as elasticity and strength, as well as transport properties such as permeability depend strongly on the microstructure of the textile. Textiles are heterogeneous structures with highly anisotropic material properties, including local fiber orientation and local fiber volume fraction. In this paper, an algorithm is presented to generate a virtual 3D–model of a woven fabric architecture with information about the local fiber orientation and the local fiber volume fraction. The geometric data of the woven fabric impregnated with resin was obtained by micron-resolution computed tomography (μCT). The volumetric μCT-scan was discretized into cells and the microstructure of each cell was analyzed and homogenized. Furthermore, the discretized data was used to calculate the local permeability tensors of each cell. An example application of the analyzed data is the simulation of the resin flow through a woven fabric based on the determined local permeability tensors and on Darcy’s law. The presented algorithm is an automated and robust method of going from μCT-scans to structural or flow models.     

Nonvolatile Memories Based on Graphene and Related 2D Materials

The pervasiveness of information technologies is generating an impressive amount of data, which need to be accessed very quickly. Nonvolatile memories (NVMs) are making inroads into high‐capacity storage to replace hard disk drives, fuelling the expansion of the global storage memory market. As silicon‐based flash memories are approaching their fundamental limit, vertical stacking of multiple memory cell layers, innovative device concepts, and novel materials are being investigated. In this context, emerging 2D materials, such as graphene, transition metal dichalcogenides, and black phosphorous, offer a host of physical and chemical properties, which could both improve existing memory technologies and enable the next generation of low‐cost, flexible, and wearable storage devices. Herein, an overview of graphene and related 2D materials (GRMs) in different types of NVM cells is provided, including resistive random‐access, flash, magnetic and phase‐change memories. The physical and chemical mechanisms underlying the switching of GRM‐based memory devices studied in the last decade are discussed. Although at this stage most of the proof‐of‐concept devices investigated do not compete with state‐of‐the‐art devices, a number of promising technological advancements have emerged. Here, the most relevant material properties and device structures are analyzed, emphasizing opportunities and challenges toward the realization of practical NVM devices.     

基于 NAND Flash 的嵌入式文件系统设计

主要介绍了针对 NAND Flash 型存储器设计的嵌入式文件系统. 其硬件平台是为了顺应多功能、大容量集成化存储的需求而开发的基于 ADSP-BF532 芯片与 NAND Flash 结合的高性能嵌入式存储系统. 此存储系统采用了多片并行流水的存储模式,开发出独特有效的闪存管理技术与改良的文件系统,通过设置访问权限实现多用户管理,使得处理器、存储器以及文件管理层软件的多方优势得以充分发挥.     

超大尺寸激光测距大型测控网络研制

为了解决超大尺寸激光测距过程中所面临的测量任务大、测量点数多、数据庞大和巨型数据处理困难等问题,设计了超大尺寸激光测距大型测控网络的研制方案。提出将云计算平台与大型测控网络相结合,使得若干台具有串口通信功能的仪器协同工作,获得更强大的测量能力,实现了多种无线网络融合,并解决海量数据的存储及数据处理问题。实验结果表明:系统内存设定为2G,虚拟机硬盘设定为500G,当数据存储量超过500G时不会出现不能继续存储的问题,测量数据可以准确地被存储到云平台;一次性处理数据量超过2G时不会出现内存不足的问题,能够实现巨型数据的处理问题;Matlab和虚拟机结合能够很好的完成复杂运算任务,快速准确地确定被测关键点坐标。     

激光测振方法在笔记本电脑振动实验中的应用

振动特性的测量和分析是鉴别相关部件工作可靠性的重要手段。常用的测振技术是接触式测量,但这种测试方法对于轻薄结构存在质量和刚度的附加问题,影响测量结果的准确性。笔记本电脑结构复杂、质量轻,宜采用非接触式测量。采用激光测振方法,首先对笔记本电脑结构进行实验模态分析。对于一台笔记本电脑来说,可能引起硬盘工作不稳定的部件包括扬声器、风扇、光驱、键盘等。改变输入条件,考察影响较为显著的扬声器和风扇两个部件与硬盘之间的影响关系与笔记本电脑结构振动分布情况,为结构布局的优化提供依据。     

Fast multi-tau real-time software correlator for dynamic light scattering

We present a PC-based multi-tau software correlator suitable for processing dynamic light-scattering data. The correlator is based on a simple algorithm that was developed with the graphical programming language LabVIEW, according to which the incoming data are processed on line without any storage on the hard disk. By use of a standard photon-counting unit, a National Instruments Model 6602-PCI timer-counter, and a 550-MHz Pentium III personal computer, correlation functions can be worked out in full real-time over time scales of ~5 mus and in batch processing down to time scales of ~300 ns. The latter limit is imposed by the speed of data transfer between the counter and the PC's memory and thus is prone to be progressively reduced with future technological development. Testing of the correlator and evaluation of its performances were carried out by use of dilute solutions of calibrated polystyrene spheres. Our results indicate that the correlation functions are determined with such precision that the corresponding particle diameters can be recovered to within an accuracy of a few percent rms.     

Electrical properties of nanocomposites near percolation threshold - dynamics

The paper deals with analysis of morphology and electrical properties of (nano)composite films. It describes a computer simulation tool for morphological and transport analysis of the films. Two models of composite structures are prepared — a hard disk and soft disk model. Their morphology is studied by the covariance, Quadrat Counts method, and Voronoi tessellation. Some specific characteristics of the methods are introduced. The electric properties are studied by the Monte Carlo simulations via tunnel charge transport. The results for d.c. conductivity as well as in case of changing voltage are done.     

基于Ga-SbTe的高性能相变存储单元的设计和仿真

相变存储器(PCM)因依靠电阻率的变化来存储的模式,成为65nm以下非易失存储器应用的研究热点.然而,相变存储器的擦写功耗、复位电压、热稳定性和擦写寿命一直是相变存储器发展的几个瓶颈.对此,设计了一种基于相变合金Ga3Sb8Te1的新型嵌入式相变存储器,并建立有限元(FEA)热学,结晶动力学和SPICE宏模型.通过瞬态热学和结晶动力学仿真表明,基于Ga3sb8Te1的相变存储器具有更高的热稳定性和可循环擦写次数、更低的复位功耗,更快的置位频率,是一种较为理想的高性能相变存储器.     

Design and Load/Unload Performance of Hard Disk Drive Suspension Integrated With Shape Memory Alloy Thin Film

We propose a new load/unload (L/UL) suspension featuring shape memory alloy (SMA) thin film and demonstrate its effectiveness through the L/UL simulation. We estimated the mechanical properties of the SMA with respect to the material phases by experiment and designed the proposed suspension by considering the vibration modes related to the L/UL performance. In order to effectively verify the effectiveness of the proposed suspension, we designed the suspension to have similar L/UL performance to that obtained from the conventional suspension when the SMA film is not activated. After analyzing the L/UL design parameters of the proposed suspension when the SMA is activated, we examine the relative performance of the conventional and proposed suspensions by L/UL simulation by comparing the vibration motions of the slider and the minimum gap size between the disk and slider