基于三维CAD的机械制图课程改革中的习题配置

工程设计现在已发展到全数字阶段,能使设计、制造一体化过程得以实现的核心是三维实体模型,二维投影图已满足不了形势发展的需求.因此,基于三维CAD绘图技术,我院开展了机械制图课程"3D实体教学法"的教学改革,其思路一是直接从3D实体图形开始学习,而不是传统的从投影概念、2D投影视图开始学习,二是以3D实体造型而不是传统的以画法几何作为教学的基本核心.在此基础上,提出了一种以"使学生成为自主学习者"为目标,突出"三维"和"设计"新思想,在习题配置这一环节上所进行的配套措施,以此来深化教学改革.     

基于三维CAD的机械制图教学中的"美育"

三维CAD技术的迅速发展,为欣赏现代工程图学具有美的特性提供了一个有效的方式.介绍了"机械制图"课程教学中如何渗透"美育"的具体举措,旨在配合、支持和丰富基于三维CAD的"工程制图"课程改革,激发学生对该门课程更多的兴趣,使学生的专业能力与审美能力得到和谐发展.     

微流控芯片计算机辅助设计、辅助制造方法研究

介绍了一种采用计算机辅助制造中快速成型技术实现微流控芯片快速制作的方法。采用VB二次开发工具(VBA),在计算机辅助设计(CAD)二次开发平台上建立微流控芯片三维CAD立体模型,并通过计算机软件算法对CAD模型进行分层切片,为实现微流控芯片计算机辅助制造提供加工数据。文中针对微流控芯片加工精度要求高的特点,提出了采用位图数据图像格式(BMP)数据格式取代快速成型分层切片中常用的三角面片数据格式(STL),并对具体实现方法进行了详细介绍。     

Synthesis and characterization of LiCo<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Mn<Subscript>2−<Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>4</Subscript> powder by a novel CAM microwave-assisted sol–gel method for Li ion battery

LiMn₂O₄-based spinels are of great interest as positive electrode materials for lithium ion batteries. LiCo _x Mn_2−x O₄ (x = 0.0, 0.1, 0.2, 0.3, and 0.4) spinel phases have been synthesized by novel citric acid-modified microwave-assisted sol–gel method. The structural properties of the synthesized products have been investigated by X-ray powder diffraction and scanning electron microscopy. To improve the recharge capacity of Li/LiCo _x Mn_2−x O₄ cells, the electrochemical features of LiCo _x Mn_2−x O₄ compounds have been evaluated as positive electrode materials. The structural properties of Co-doped oxides are very similar to LiMn₂O₄ electrode. Techniques like cyclic voltammetry, charge–discharge and cycle life are also used to characterize the LiCo _x Mn_2−x O₄ (x = 0.0, 0.1, 0.2, 0.3, and 0.4) electrodes.     

SN方法粒子输运计算程序自动建模关键技术问题研究

在充分调研和分析SN方法粒子输运计算程序自动建模方法的基础上，对建模过程中的模型文件格式识别、属性编辑、空腔处理及自动划分离散网格等关键技术问题进行了研究，并提出了合理可行的解决方法。通过对SNAM程序建模部分功能测试，验证了这些方法的正确性和有效性。This paper presents two approaches to enhance the geometry modeling ability of SN particle transport simulation codes and focus on the key issues that lie in the processing from CAD model to SN code geometry model, e.g. CAD file format support, void modeling, mesh generation and model-editing. SNAM （SN Automatic Modeling system） has been developed as an interface code between commercial CAD software and SN particle transport simmulation codes. The testing results have shown that the algorithm and implementation used in SNAM are efficient and capable of all the necessary processing from CAD model to SN geometry model.     

New Voronoi Diagram Algorithm of Multiply-Connected Planar Areas in the Selective Laser Melting

This paper studies the practical generation of Voronoi diagrams for multiply-connected planar areas bounded by line segments. The core of the algorithm was calculating Voronoi polygon of every Voronoi object in planar areas independently. The main approach had two steps. The first step was calculating all relevant bisectors of every Voronoi object. The second was combining obtained bisectors into completed Voronoi polygons individually. All code was implemented in Visual C++ platform. The resulting code was extensively tested in real-world data and its practical running time grew only linearly. Three statistical CPU-consumption charts had been drawn with the Voronoi diagrams computation data, and compared with other published codes for computing Voronoi diagrams. The algorithm was applied to compute offsetting of slice area consisting of large-scale line segments for the selective laser melting (SLM) trajectory scanning technology which is a kind of rapid prototyping (RP). The experimental results of offsetting for slice area based on Voronoi diagrams show that the approach is effective and simple for polygon offsetting problems. The method is helpful to those offsetting work and can provide more effective offsetting solution.     

基于Projector的球罐表面测地线展开法

基于投影工具Projector,提出一种实用的球罐表面展开方法.过球罐表面上一系列测地线将罐体表面划分为小块,提取每一小块的曲面边界曲线作为输入项逐一进行计算、连线并自动生成展开图,最后再集拢到展开后的球罐外表面.与传统的方法相比,应用该方法对球罐表面进行展开可以保证焊缝的长度最短,且展开过程形象直观.故球罐的质量、安...     

试论CAD/CAM一体化技术

一般来说,企业在产品的设计和制造过程中,设计、生产、加工三个环节都是独立进行的,存在数据交换靠人工进行,资源不能共享等弊端。这样不仅降低了设计和生产效率,带来许多人为因素,而且影响产品质量。为此,自上世纪70年代以来,人们开始研究CAD和CAM之间的数据和信息的自动传递和转换问题,到目前为止,已取得了很大的进展,达到了实用的水平。本论述就CAD/CAM一体化技术的发展过程、趋势及常见流行软件作一一介绍。     

最优解耦综合控制及其在除氧器控制中的应用

本文基于W.A.Wolovich的最优解耦思想,提出了多变量离散系统的最优解耦综合控制规律,为计算机控制系统的解耦并且最优设计提供了理论依据。研制了用于多变量连续系统和离散系统的最优解耦综合控制的计算机辅助设计应用软件包,并成功地将其应用于火电厂除氧器群的解耦控制设计。     

计算机辅助成组技术的研究

成组技术(GT)是改变多品种、中小批量生产落后面貌的卓有成效的技术、组织措施.实施成组技术的关健在于零件的排序、特征统计、分类归组及原有图纸、工艺工装的检索.本文针对上述几个关键问题的计算机解法进行了初步的探讨,其程序在IBM-PC计算机上运行获得了成功.