参数化变型设计中工程图调整技术优化研究

针对工程图调整技术所存在的方法不完善,耗时长,过程繁杂等不足,对其进行了优化。分析了常用视图比例调整方法的优缺点,完善了其调整过程。研究了模型边线的伸缩规律,提出了尺寸直角的概念,并通过绘制基于尺寸直角的装配布局草图,简化了视图位置调整过程。提出了标注约束元的概念,论述了其对尺寸、注释位置变化的影响,并通过采用基于标注约束元的标注方法,简化了尺寸、注释调整过程。     

扫描工程图二维重建中约束关系的建立及表示研究

主要研究扫描工程图矢量化后的二维重建的有关问题。较为详细地阐述了结构约束识别模块及尺寸约束的表示，并提出了用无向有权图来表示图素间的结构约束，用权来表示图素间结构约束的类型。将尺寸约束表示模型引入到工程图纸的二维重建，从而为尺寸驱动模块的建立奠定基础。     

工程图扫描图象中剖面区域的整体识别

工程图的识别一直是ＣＡＤ研究领域的难点和热点问题，传统的基于细化的算法本质上是一种局部算法，在得到骨架的同时，在分叉点产生变形，并且得不到工程图的整体信息，提出用最大优无度原则及三个辅助原则来提取剖面线和剖面区域，以减少对后续步骤的干扰，并是剖面区域的整体信息，本文提出的算法已经实现，在浙江大学ＣＡＤ＆ＣＧ国家重点实验室开发的工程图纸扫描识别系统中得到检验。     

检验工程图中尺寸封闭的算法

对用计算机绘制的工程图中尺寸标注的封闭现象进行了分析。将尺寸标注系统转换成无向图的形式,然后采用一种智能路径搜索的算法,对无向图所对应的邻接矩阵进行遍历,完成对整个标注系统中的所有尺寸标注搜索的过程。通过邻接矩阵的状态变化来对工程图中尺寸标注的封闭现象进行检验。这种新的计算方法实现了在一个标注系统中对多个尺寸封闭现象的无丢失查找。     

由三维参数化模型生成工程图的自动调整技术

针对由三维参数化模型自动生成的工程图中视图布局较差,比例不合理,尺寸标注不整洁,线条繁杂,注释错误等缺点,根据企业给定的工程图模板及相应标准,研究了工程图模板创建与保存方法、三维模型驱动后工程图视图布局、比例、特征尺寸、焊接符号、零件序号的调整方法,以及部件图明细表的自动生成与调整方法.     

立式袋装机三维数字模型生成二维工程图的实现

探讨利用Solid Edge软件对立式袋装机设计过程中,三维参数化模型自动生成的工程图时的视图布局较差,尺寸标注不整洁,线条繁杂等缺点,研究了如何根据国家标准,设置工程图模板、零件图与剖视图生成与调整方法、以及部件图明细表的自动生成与调整方法.从而使立式袋装机三维参数化模型快速生成符合国家标准的二维工程图.     

基于图形思维的信息图形化基础课程体系的研究与实践

通过对思维学基础理论、视觉心理学及工程图学中图示图解思维方法的综合性研究，论述了“图形思维”与形象思维和逻辑思维的关系。具体分析了图形思维的基本概念及思维过程，介绍了一个新创建的并已初步实施的基于图形思维方法的信息图形化基础课程体系。为在高等教育中如何建立有效的培养大学生创造性思维的教学训练公共平台找到了一个切实可行的切入点。     

工程图信息系统——EDIS

介绍了ＥＤＩＳ（ＥｎｇｉｎｅｅｒｉｎｇＤｒａｆｔｉｎｇＩｎｆｏｒｍａｔｉｏｎＳｙｓｔｅｍ）系统的多层次处理工程图纸的方法以及在图形识别方面的新进展。ＥＤＩＳ通过对图纸数据的分层，使系统在处理图纸信息中能灵活结合自动处理、人工交互和智能辅助的方式，提高了处理的效率和实用性。文章还在图形识别的研究中提出了“轮廓匹配法”、推广的拓扑数据结构和图形矢量的鲁棒识别方法。     

现代工程设计绘图中标准化保证体系的建立

分析了在科学技术飞速发展,工程设计领域发生深刻变化的形势下,构建机械设计制图标准化保证体系的必要性。探讨了建立标准化保证体系的可行性。详细论述了构成该体系的总体框架的核心内容,并详细介绍了开发国家标准“技术制图”网络自学系统和基于尺寸驱动的标准件、常用件参数化电子书库的设计思想、结构特点和制作技术。该体系为学生在各大的设计环节中以及对教师和广大的设计者在设计绘图中提供了先进的标准化信息服务,并解决了在计算机上设计、绘图、网上查询及检索资料的问题。     

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．     

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 ...