铝型材推弯工艺

通过铝型材圆环的推弯实验,研究了推弯工艺原理、变形过程,结合有限元模拟得到了和实验结果相吻合的型材厚度分布、成形零件卸载回弹后的曲率半径及型材截面畸变.结果表明:推弯零件曲率及截面畸变一致性高,成形模具结构简单且便于调整,数值模拟可以用于推弯工艺的优化分析.     

Modelling spatio-temporal environmental data

A conceptual model for environmental data is presented with special emphasis on the ability to store spatio-temporal references of the data. Other aspects of the model are the ability to handle hierarchical data and semantics of the measurements. The model was tested with an implementation on an object-relational database management system. As a part of the test implementation, a forestry data set covering 75 years and 4900 hectares was loaded onto the database.     

管壳式换热器流场三维数值模拟

采用多孔介质方法 ,在PHOENICS 3 3程序的基础上建立了换热器的三维流动计算模型。引入体积穿透率、表面穿透率、分布阻力等来描述换热器内的管束。模型通过计算Halle等[1] 的实验工况来进行验证 ,并尝试用于计算 2 0 0MW低温供热堆主换热器内的流场     

COM组件接口方法参数的数据类型的选择

论述了在用 Visual C+ +建造 COM组件时 ,如何选择接口方法参数的数据类型的问题。结合客户程序是 ASP应用程序的情景 ,讨论利用 Visual C+ +和 ATL ,如何在组件程序的一端选择相应的数据类型。     

多孔挡板流化床还原UO3反应器模型的研究

针对ＵＯ＿３的Ｎ＿２还原反应建立了多孔挡板流化床反应器模型。将多孔挡板床的每一级视为具有相似的流动状态，每一级的上、下段称为稀、密相段，分别用鼓泡床和活塞流模型描述。该模型的计算值与￠６３ｍｍ的多孔挡板床Ｈ＿２还原ＵＯ＿３的热态实验值能较好的吻合。还预计了还原温度、操作气速和挡板结构参数对固相转化率的影响，为该类反应器的工业设计、放大和优化提供了依据。     

Rendering of Surface and Volume Details in Volume Data*

Aiming at the detail rendering in volume data, a new volume illumination model, called Composed Scattering Model (CSM), is presented. In order to enhance different details in volume data, scattering intensity is decomposed into volume scattering intensity and surface scattering intensity with different weight functions. According to the Gauss probability distribution of gray and gradient of data, we propose an accurate method to detect the materials in a voxel, called composed segmentation. In addition, we discuss the principle of constructing these weight functions based on the operators defined in composed segmentation. CSM can generate images containing more details than most popular volume rendering models. This model has been applied to the direct volume rendering of 3D data sets obtained by CT and MRI. The resultant images show not only rich details but also clear boundary surfaces. CSM is demonstrated as an accurate volume rendering model suited for detail enhancement in volume data sets.     

Non-steady-state model for kinetics of free radical polymerization, 4. Direct thermal initiation

This paper deals with the non-steady-state kinetics of direct thermal initiated polymerization. The initiation is assumed to be a bimolecular reaction of the monomer. The relationship between the radical concentration and the monomer conversion is rigorously derived. In further treatment a few very close approximations are introduced based on the fact that the number of monomer molecules reacting in the initiation step is much less than that consumed in the propagation step for a process producing high polymer, and the value of the rate constant for propagation or chain transfer is much lower than that for chain termination. Expressions for various molecular parameters, such as molecular weight distribution, number-average and weight-average degrees of polymerization, and dispersity, are given. Several numerical examples are provided.     

Geometric features of the flame propagation process for an SI engine having dual‐ignition system

Flame front surface area and enflamed volume (the volume enclosed with flame front) is theoretically analysed for a spark‐ignition engine, having cylindrical disc‐shaped combustion chamber with two spark plugs located axisymmetrically on cylinder head, between cylinder axis and cylinder wall. Spherical flame front assumption is used. A computer code is developed based on purely geometric consideration of the flame development process in combustion chamber, and is used to investigate the effects of variations of spark plugs' locations on geometric features of the flame front. A comparison has also been made with a spark‐ignition engine having one spark plug at the same location. Copyright © 2002 John Wiley & Sons, Ltd.     

步进式加热炉炉温优化设定模型及软件开发

针对线材厂步进式加热炉实际工况，提出了基于经验规则的炉温优化设定模型和在线自学习获取知识的思想，并以炉温优化设定模型为核心，开发出加热炉计算机控制系统的优化运行软件。     

面流消能近底紊动流速特性的研究(面流消能试验研究之一)

本文主要论述了面流消能五种典型流态近底紊动流速特性,总结出了近底时均流速和紊动强度沿程变化规律,提出了近底紊动流速可能出现的最大瞬时值及相应位置的计算公式。面流消能工程的下游防冲设计中考虑的主要水力参数之一是,消能段近底流速紊动可能出现的最大瞬时值及其相应的部位,但目前国内外研究成果较少。笔者通过水工模型试验重点研究了面流消能各典型流态近底流速及其紊动纵向分量沿程的变化规律,并提出了计算公式,为优化面流设计提供科学依据。