DDE技术在参数化CAD中的应用

本文从分析现有微机参数化机械设计CAD系统入手,指出了该类系统在进行的所谓参数化设计中所存在的问题和不足;同时推出了一项新的参数化CAD系统的设计技术——基于Windows应用间动态数据交换DDE技术的参数化机械设计CAD系统开发软件技术。文中阐述了基于DDE技术的参数化CAD系统开发的一般方法和应用环境。     

基于XML的YH30型液压机设计方法研究

以YH30型液压机为例,根据零件的特征参数利用DOM自动创建XML文档,并通过解析XML文档获取存储在文档节点中的零件尺寸,将它作为SolidWorks参数化建模中的关键尺寸.这种方法实现了SolidWorks参数化设计技术和XML数据库技术的结合,为异构CAD平台的数据交换和信息集成提供了一条有效途径.     

XML在数据交换中的应用

XML能够适应多样的不断变化的网络应用环境,被广泛应用于异构系统间数据交换。本文首先介绍了XML用于异构数据交换中的相关相关技术,最后以某电子政务系统为例,介绍了XML在数据交换中的具体应用。     

应用并行技术实现CAD／CAM的高度集成

传统的CAD/CAM系统由于设计思想本身的局限性,其内部只能达到一种松散的基于数据交换的低水平的集成,产品的设计方法也不符合工程技术人员的设计思路。本文提出了基于全耦合的单一数据模型的并行CAD/CAM系统设计思想,使得CAD/CAM系统内部达到以数据共享为基础的高度集成。并行CAD/CAM系统充分体现了工程技术人员的思维方式及产品设计过程的反复性和协调性。此外,文中还提出广义参数化设计的新概念,它与特征设计方法的有机结合保证了产品模型的完整性和产品设计过程的同步性。特征共享是实现CAD和CAM集成的关键因素。并行CAD/CAM系统应用面向对象软件设计思想,实现了复杂数据模型的内部封装,并为数据模型和功能模块之间提供简单直观的界面。面向对象设计方法是开发并行CAD/CAM系统的有效手段。     

基于约束图的三维服装约束问题求解

采用样条曲线作为基本几何元素,建立了三维服装几何约束关系。以此为基础构造了三维服装的约束图,有效地表达了几何元素及其相互关系。提出了基于约束图的改进的三维服装几何约束求解方法,完成了构造服装和对服装的交互参数化修改问题。通过应用实例将参数化方法向高层次图素进行了推广,并成功应用于服装CAD系统中,运行效果良好。     

应用LabVIEW中.NET组件建立Web Services的研究

Web services作为新一代的基于web的网络信息交换技术的逐步应用,为异构测试系统数据交换提供了新的途径。文章介绍了Web services.、NET等相关技术在LabVIEW中的应用情况,描述了如何利用微软的.NET技术在LabVIEW中应用Web Services,实现基于web的网络间异类系统之间的数据交换,并以具体例子演示如何在LabVIEW中实现Web Services应用。     

应用LabVIEW中.NET组件WebServices的研究

Webservices作为新一代的基于web的网络信息交换技术的逐步应用。为异构测试系统数据交换提供了新的途径。文章介绍了Webservices，NET等相关技术在LabVIEW中的应用情况。描述了如何利用微软的．NET技术在LabVIEW中应用WebServices。实现基于web的网络间异类系统之间的数据交换，并以具体例子演示如何在LabVIEW中实现Web Services应用。     

B样条曲线曲面降阶综述

B样条曲线曲面的降阶是样条曲线和曲面造型中的关键技术之一,为了实现不同CAD系统之间的数据交换,常用到这一技术,它已成为热点问题,得到越来越多的研究.结合作者在该领域的研究成果,文章综述了近年来国内外专家学者关于B样条曲线曲面的降阶逼近研究的方法、理论成果及实际应用情况,并对各种不同的方法进行了分析比较.     

手绘草图识别技术及其建模方法研究

手绘草图识别技术是计算机支持的交互式草图设计系统中的核心问题,针对这一问题,提出了一种手绘草图识别算法,主要包括手绘草图原始笔划的数据前处理、基于多次检测算法的特征点识别、草图分段识别、空间位置解释、图形重构等内容.本文利用多次识别算法,可以有效解决手绘草图模糊性及拐点和折点不确定性,基于这一技术的三维草图CAD建模方法已在自行研发的CAD软件中得到应用,并取得了良好的效果.     

基于飞机设计的IGES图形数据交换

根据飞机概念设计系统同其他CAD/CAM系统通过IGES标准进行数据交换遇到的问题为例,介绍IGES图形交换标准的重要性,总结在飞机设计(SAD/CAM系统中应用IGES标准传输图形数据时需要注意的问题和解决方法,满足飞机设计在研制过程中使用CAD/CAM时数据传输的需要.此外还分析在IGES标准基础上发展起来的STEP标准出现的原因及其应用前景.     

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.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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 ...