In-plane directional mechanical properties of carbon fabric skins in sandwich structures after thermoforming

In this paper, a representative unit volume finite element (RUV FE) model was employed to simulate thermoforming process of carbon fabric-polymeric foam sandwich structures. Thermoforming simulations, which capture crimp angles and amplitude changes of carbon fabric with respect to different operational pressure, were conducted with the help of RUV FE model. Micro-deformation of tow structures after thermoforming was rigorously reflected in the second stage FE model to determine the in-plane directional stiffness of skin parts. Tensile tests were carried out to investigate mechanical properties of skin parts in sandwich structures for the potential usage of automotives, electronic housings or the satellite structure design.     

Image segmentation via self-organising fusion

A method called self-organising fusion (SOF) for performing fast image segmentation is presented. The input image is divided into a set of small regions, each associated with a working feature. First, all regions are simultaneously updated and then a statistical process is applied to merge the qualified regions. The contours of objects are obtained by alternating the two processes of updating and merging until convergence. The concurrent updating creates a SOF behaviour that facilitates the identification of regions presumably comprising the same object. The method can save computation cost as both updating and merging are conducted in parallel fashion, and as parameter selection is done for local regions, it is able to deal with fairly complex images     

基于DDS的快速跳频源设计

在简要介绍跳频通信技术的发展概况及跳频源合成主要方法的基础上,针对目前普遍采用的DDS技术,详细分析了其输出频谱特性,并由此引出了基于DDS的跳频源设计方案,然后详细分析了设计原理、实现的可行性以及软件的设计和流程图,同时对主要芯片的性能指标及特点作了说明。此设计通过优化,提高了各项性能指标,对整体跳频通信收发机的性能有了很大的提升。     

100吨电炉自动控制系统设计及改进

本文介绍了安钢100吨电炉两级自动控制系统的设计方案，详细阐述了一级、二级自动控制系统的配置和功能，对于系统运行中出现的问题，提出了改进方案。     

Dynamic deformation behavior of ultrafine-grained low-carbon steels fabricated by equal-channel angular pressing

The dynamic deformation behavior of ultrafine-grained low-carbon steels fabricated by equal-channel angular pressing (ECAP) was investigated in this study. Dynamic torsional tests, using a torsional Kolsky bar, were conducted on four steel specimens, two of which were annealed at 480 °C after ECAP, and then the test data were compared in terms of microstructures, tensile properties, and adiabatic shear-band formation. The equal-channel angular pressed specimen consisted of very fine, equiaxed grains of 0.2 to 0.3 μm in size, which were slightly coarsened after annealing. The dynamic torsional test results indicated that maximum shear stress decreased with increasing annealing time, whereas fracture shear strain increased. Some adiabatic shear bands were observed at the gage center of the dynamically deformed torsional specimen. Their width was smaller in the equal-channel angular pressed specimen than in the 1-hour-annealed specimen, but they were not found in the 24-hour-annealed specimen. Ultrafine, equiaxed grains of 0.05 to 0.2 μm in size were formed inside the adiabatic shear band, and their boundaries had characteristics of high-angle grain boundaries. These phenomena were explained by dynamic recrystallization due to a highly localized plastic strain and temperature rise during dynamic deformation.     

端部中空离子源的磁路研究

研究了端部中空离子源的磁路设计.在简要叙述端部中空离子源的基本原理及其对磁场要求的基础上,考虑了在设计离子源磁路时的关键问题和解决方法,并给出了实验结果和分析结论.     

Reconfigurable Web wrapper agents

Web wrapper agents exploit online Web data sources, facilitating information integration and reuse. With the DeepSpot Agent Toolbox, users can automate virtually all types of Web browsing sessions simply by browsing the target Web sites.     

A comparative study of exchange and aggregation models in the B2B e-marketplace

This research seeks to provide an economic framework for understanding two major forms of e-marketplaces: aggregation-oriented vs. exchange-oriented e-marketplaces. By analyzing the marginal benefit per transaction in alternative models, we are able to determine the most suitable B2B e-marketplace for a wide variety of product categories, market conditions, and procurement methods. For example, when companies sell commodities in a fragmented market, the aggregation model is suitable for spot purchasing, and the exchange model works best for systematic purchasing. In addition, the effect of supplier consolidation and information technology-enabled cost reduction on model selection is discussed.     

电容式两相流层析成象系统仿真研究

以油料在管道中输送为例进行电容层析成象仿真.利用有限元方法对电场建立数学模型,在SGI indigo 2 工作站上,使用AVS可视化软件和反投影算法,对3种典型流态模型反演及显示其流体成份分布的图象.     

焦化废水中多组分酚的因子分析—岭回归-光度法同时测定

根据3-甲基-2-苯并噻唑腙(MBTH)与酚类发生偶合显色反应而生成有不同颜色的稳定配合物的特点,测定废水中酚类混合体系的吸收光谱,结合因子分析和岭回归技术对工业废水中苯酚、邻甲酚、3,4-二甲酚、2,3-二甲酚、邻苯二酚等多组分酚的光谱数据进行解析,成功的确定了废水中酚的物种数,物种种类及各物种含量.