高土石坝工程安全评价与预警信息管理系统

基于现场监测数据及先进的数值分析方法,建立土石坝全生命周期的工程安全评价及预警信息系统,是目前土石坝发展的必然趋势。以糯扎渡高心墙堆石坝为依托,开发了理论严密、方法先进且可靠实用的大坝工程安全评价与预警信息管理系统。该系统由系统管理模块、安全指标模块、监测数据与工程信息模块、数值计算模块、反演分析模块、安全预警与应急预案模块和数据库及管理模块共7个模块构成。其中,数值计算和反演分析模块可利用所取得的坝体监测数据,进行渗流、大坝应力变形、坝体裂缝、地震动力反应和坝坡稳定等土石坝关键计算分析,是本系统的核心部分。利用工程前期已经取得的坝体变形监测数据,对坝体进行了变形反演分析并对大坝关键时间结点的形态进行了预测分析。     

AutoCAD 中基于超图约束驱动参数化设计的实现

 使用超图表示约束模型,采用基于超图约束驱动的几何推理约束满足法进行参数化设计,几何实体的计算基于特征点。作者结合在ＡｕｔｏＣＡＤ上开发参数化设计模块的实践,得出该方法能处理多实体约束关系（如面积约束）,提高求解效率,降低时间复杂度。     

AutoCAD中基于超图约束驱动参数化设计的实现

使用超图表示约束模型,采用基于超图约束驱动的几何推理约束满足法进行参数化设计,几何实体的计算基于特征点。作者结合在AutoCAD上开发参数化设计模块的实践,得出该方法能处理多实体约束关系(如面积约束),提高求解效率,降低时间复杂度。     

基于CATIA技术的飞机典型零件变型设计

为提高产品设计效率,研究了组件框架技术,借助CATIA二次开发平台,在参数化建模技术的基础上实现对飞机典型零件的变型设计,快速提取特征信息,实现智能化操作.利用面向对象的程序语言,开发出与CATIA系统集成的变型设计模块,能够提高飞机典型零件的设计效率.以飞机典型零件机加件中的拉杆为例,对变型设计方法的验证表明,利用CATIA二次开发技术以及CAA编程工具,能够对飞机典型零件参数化建模,实现变型设计.     

基于实例推理的小型液压机参数化

结合小型液压机企业的实际需求,充分利用现有资源,基于实例推理的思想,引入参数化理论和有限元技术,采用vc++对SolidWorks进行二次开发,开发了一个由参数化CAD模块、数据库模块和有限元分析与优化模块构成的小型液压机参数化CAD系统.使用结果表明该系统大大提高了设计效率.     

过程装备产品设计系统的研究与开发

以面向对象思想和参数化造型技术为指导,通过C 程序语言、MS SQL Server2000数据库和UG NX二次开发工具,构建过程装备产品设计系统,最终实现过程装备部件的结构设计计算、三维几何模型快速造型以及模型管理等功能.详细介绍了该系统的体系结构及实现方法,着重阐述设计计算、几何造型、数据管理等功能的实现方法,并以换热器为实例加以说明,其他过程装备可在系统框架下方便地扩充.     

面向工程的专用产品参数化CAD系统的研究

 针对目前参数化CAD系统的不足，提出了面向工程的参数化思想，引入了功能约束，分析了对功能约束进行处理的3种方法．采用了基于特征的参数化造型方法，用应用层、描述层和图形层三层体系表达基于特征的参数化模型，将该模型作为参数驱动的基础．将设计中的约束分为3类：工程约束、适配约束和几何约束．通过适配约束在工程约束与几何约束间建立映射关系，使得参数化设计系统既可以受几何参数的驱动，又可以受工程参数的驱动，从而扩大了CAD技术对设计过程支持的范围。     

基于影像的内燃机曲轴随动自动检测技术

为实现内燃机曲轴关键几何尺寸的快速、自动、精密测量,研发了一种基于影像测量原理的内燃机曲轴随动自动精密检测系统.介绍了测量原理及系统方案,包括光学成像系统的设计与选型、4轴随动机械结构的设计方案等;介绍了系统检测流程以及面向曲轴特征影像的核心图像处理算法及特征提取技术;进而提出了光学成像系统的标定方法,并对标定过程中的难点设计了解决方案;进行系统集成,开发了曲轴检测样机,并开展工程应用.应用结果表明,本技术实现了对曲轴沟槽及直径参数的快速、自动、精密检测.     

基于模块的零部件参数化设计系统的研发

阐明了模块化的概念,提出了模块化设计结构的特征,在阐明参数化设计方法基础上,将模块化思想与参数化设计方法相结合,并利用SolidWorks二次开发技术,研究并提出基于模块的零部件参数化设计系统的框架和实施步骤．最后以北京桌公司的减速器为应用实例,实现减速器模块的参数化设计系统验证,并获工程应用．     

CAD／CAE集成的三偏心蝶阀参数化设计

抽取影响蝶阀性能的几何参数,建立参数化模型,在Solidworks环境中利用VBA实现了蝶阀零件的参数化建模.将模型导入有限元分析环境,实现了CAD/CAE的集成.有限元计算表明,参数化模型可以实现不同参数几何模型的快速重构,为数字化设计和方案优化提供了可能.     

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.