截面多轮廓数据排序算法

针对逆向工程领域截面数据预处理中的多轮廓排序问题,提出了一种简便有效的链表法.该算法分为粗排序和精确排序两步,首先通过极角进行粗排序,然后利用带有访问标记的链表来完成精确排序.通过实例表明,链表法能够对截面单轮廓数据和多轮廓数据实现有效地排序.这为逆向工程中后续的曲线拟合和曲面重构奠定了基础.     

字形轮廓的精确表示及其在文字向量化中的应用

从二进制图像中提取轮廓是许多图像处理应用中的重要内容,例如:扫描文档图像的向量化、对象分割、模式识别、手写文档和AutoCAD绘图中的内容解释、手绘卡通动画等。本文提出的轮廓跟踪算法能够生成具有以下特性的精确轮廓描述:首先,它能够有效地处理单像素宽度以及自相交的字形轮廓;其次,在轮廓跟踪的过程中,该算法可以将内、外轮廓与相应的对象区域相关联(例如字母‘B’由一个外轮廓与两个内轮廓组成),这将有利于对象的后续处理过程;第三,与传统的8-邻域或4-邻域连通轮廓跟踪算法相比,本文的方法能够精确地捕捉到字符的形状和尺度信息,这对于提高对象的保真度是十分重要的;最后,本文的算法简明,易于实现。     

基于Level Set的交互式快速分割算法

三维医学图像数据量大,并且受噪声、边界模糊等原因的影响,致使三维分割过程消耗时间较长,容易产生欠分割或过度分割。针对以上问题,提出一种基于Level Set的三维快速分割算法,采用Fast Marching获取二维分割区域,优化轮廓边界,利用直线数值微分算法（Digital Differential Analyzer,DDA）提取轮廓像素;进一步引入扫描线种子填充思想,实现医学图像的三维快速分割。实验结果表明,上述算法能够快速准确地分割出感兴趣区域。     

三维装配设计系统的关键技术——零部件位置编辑的研究与实现

介绍了三维装配设计系统的功能及装配特征的概念，运用面向对象的方法，进行了系统设计与分解。在此基础上，详细介绍了装配设计中编辑零部件位置的重要性及其算法实现：即利用装配零部件过程中生成的配合信息，在移动零部件时，重新计算相关零部件的配合约束，以更新零部件的位置。实践证明，该算法稳定可靠，能够较好地满足应用要求。     

AutoCAD与ParaSolid三维边界模型信息直接交换

对ACIS和ParaSolid的三维实体边界表达数据结构进行分析,基于DwgDirect接口技术,直接打开AutoCAD的DWG文件,对AutoCAD的DWG文件中基于ACIS的三维实体边界信息遍历,获取实体边界的拓扑信息和几何信息;基于ParaSolid提供的API开发函数,通过实体拓扑构造、实体几何构造和几何与拓扑附属关联,实现AutoCAD与ParaSolid三维边界模型的直接交换。最后给出一个直接交换实例。     

基于特征识别的轴类零件二维工程图的自动编程

提出基于实体类型编码和特征编码实现轴类零件自动编程的方法。给出基于节点集的实体打断方法,运用逆时钟最小夹角法,搜索出外轮廓。然后对构成外轮廓的各实体进行类型编码和特征编码,并据此进行主特征提取和辅助特征重构。根据重构后的外轮廓自动生成数控车床能识别的代码。在AutoCAD2002环境下,以ObjectARX为开发工具,用某一典型轴类零件对本文提出的原理和方法进行了验证,结果表明,自动编程效果良好。     

基于改进活动轮廓模型的矢量边界更新方法

针对GIS中地物矢量边界更新繁琐和低效的问题,提出了一种基于活动轮廓模型的矢量边界自动更新方法.以现有的GIS矢量边界为初始位置,以遥感影像信息作为轮廓形状演化的驱动力,融合遥感影像与GIS数据信息,在二者交互作用下实现GIS矢量边界更新.针对活动轮廓模型演化过程中缺乏移动范围约束的缺陷,可利用历史遥感影像目标边界点进行采样,估计目标大体轮廓形状,对活动轮廓模型的移动进行约束.实验表明,该方法可得到更好的矢量边界更新效果.     

装配工艺信息建模技术在信息集成中的应用

为了解决制造行业中异构系统间的装配工艺信息交互问题,建立了基于IDEF1x的装配工艺信息模型,本信息模型描述了装配工艺规划过程中的产品、工艺、资源信息,阐明了基于1DEF1x的装配工艺信息的表现形式及其特点．以DELMIA（数字企业精益制造交互式应用）系统为实例,基于本信息模型,通过DELMIA二次开发技术访问、操纵并且组织制造数据库中装配工艺信息．给出了2种实现工艺信息交互的途径：XML（可扩展的标识语言）技术和oracle数据库应用．并利用实例说明了本文建立的装配工艺信息模型在DELMIA系统中的有效性．     

基于裁剪的装配图生成方法

本文通过分析比较了己有的国内外各种装配图的生成方法，提出了一种新的装配图生成方法──裁剪装配法。这种方法将装配图信息离散为直线段、圆弧、圆三种基元，以待装配零件的轮廓所构成的环为裁剪窗口，作裁剪运算，进行消隐生成装配图。该方法能够适应复杂的、变化的装配关系，在实际运用中取得了较好的效果．     

基于MBD的装配管理系统的应用研究

研究MBD技术、ADO连接技术和复杂零件的装配工艺过程,介绍了MBD装配模型设计流程.在建立复杂零件MBD装配模型的基础上,采用UG平台导入产品三维模型,并运用VC++6.0对UG进行二次开发,引入产品的各个MBD装配模块.为实现产品的生产装配工艺信息及产品订单信息等数据录入和信息共享,提出了在UG界面共用产品MBD模型录入信息与装配车间管理系统数据库的存储方法.应用Java语言,对装配管理系统进行开发.运用ADO技术,实现了装配管理系统直接从数据库调用已录入的产品数据信息.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.