TiAl基合金板材制备技术的发展现状

综述了TiAl基合金板材制备技术的发展现状。介绍了的制备TiAl基合金板材三种技术的工艺过程及制得的TiAl基合金板材的显微组织和力学性能。     

不同粉末粒度的粉末轧制多孔钛板的孔隙性能研究

为满足湿法冶金、氯碱、水处理、制药等行业对多孔钛板过滤元件的需求,以粉末轧制法制备多孔钛板为出发点,开展了满足轧制工艺要求的多孔钛板粉末轧制、烧结、性能测试等研究。通过对不同性能的钛粉进行粉末轧制、真空烧结,制得了宽度为420 mm、厚度不同、组织均匀的多孔钛板,研究了不同粉末性能对其孔隙度、最大孔径和透气度的影响。结果表明:随着粉末粒度的减小,多孔钛板的密度有所增大,孔隙度、最大孔径和透气度逐渐减小。其中,多孔钛板最大孔径和透气度的变化规律与模压多孔材料的相同。在追求孔隙度最大化时,以最小的轧制压力轧制成型多孔钛板,粉末粒度越大,其厚度越大。当粉末粒度相同时,多孔钛板厚度越大,其内部孔道路径越长,孔结构越复杂,气体在透过多孔结构通道时所消耗的能量也越多,透气度则越低。     

Corrugated laminate homogenization model

This work addresses the problem of finding a substitute material model for describing the load response of globally flat corrugated sheets made from multidirectional laminates. Exact solutions of the equations governing thin singly curved shells give the displacements, strains and stresses within a unit cell extending over one period of the corrugation pattern. The forces reacting to enforced unit deformations determine the constitutive law of the substitute material model. The analytical results are compared with those of finite-element models.     

碳纤维布加固混凝土梁的剥离破坏

碳纤维布加固混凝土结构中剥离破坏是一种重要的破坏形式,通过九根碳纤维布加固混凝土梁的模型试验,考察了剥离承载力及剥离模式。根据试验结果和力学理论知识,对碳纤维布加固混凝土梁的剥离破坏进行了极限应力分析,建立了极限状态的判据和相应的碳纤维布剥离承载力计算方法,在计算方法中考虑了粘结正应力与剪应力的综合作用以及U形箍的横向剪切变形,与试验结果的比较表明,方法具有较高的精度,完善了碳纤维布加固混凝土梁的设计理论。     

The effect of specimen thickness on the experimental and finite element characterization of CTOD in extra deep drawn steel sheets

Recent experimental results by us have indicated that the load-drop technique can serve as a valid fracture criterion for predicting elastic-plastic fracture in extra deep drawn (EDD) steel sheets or in predominantly plane stress conditions. The purpose of this investigation is to examine the validity of aJ-integral as a fracture parameter and theJ-CTOD relation for the determination of critical CTOD in predominantly plane stress fracture (CTOD-crack tip opening displacement). Fracture tests were performed and experimental results were generated on fracture behaviour of EDD (0·06%C) steel sheets with CT specimens and using ‘load-drop’ as a fracture criterion. Critical CTOD was determined by using theJ-CTOD relation in addition to several existing techniques. A full 3-D finite element model was formulated to verify the critical load, critical CTOD and plastic-zone size. The critical CTOD was shown to increase with increasing specimen thickness and appeared to be approaching a higher limiting value. The characteristic features of predominantly plane stress fracture or general yielding fracture mechanics are summarized in conclusion     

The need for style systems in ODA

Many advanced document systems provide a formatting mechanism called ‘style sheets’ Style sheets provide a great deal of flexibility in describing a document's format, and allow easy maintenance of different house styles for a collection of documents. In this paper, we describe the basics of general style sheet systems, argue that successful document interchange must include the exchange of style sheet information, and evaluate ODA's style mechanism against this requirement.     

基于Drupal 7的HTML5布局模板的二次开发

以目前在国外广泛应用的Drupal 7为应用开发框架,结合HTML5、样式表、动态脚本和第三方插件技术,通过在WAMP平台上对Drupal进行二次开发,设计了一套具有友好界面、易添加与删除容器,并动态加载数据的布局模板.该模板采取分层设计,从根容器到目标内容容器构建页面框架;采用HTML5自适应布局设计方法,针对不同的业务需求完成个性化定制界面UI.同时介绍了利用主流浏览器调试工具对界面代码进行分析与调试.     

基于LDA主题的改进TFIDF 95598工单智能分类研究

为了提高95595工单智能分类的准确率,提出了基于LDA(Latent Dirichlet Allocation)的改进TFIDF算法。先对文本提取特征词,然后采用K-means算法进行聚类处理。构建LDA模型,获得概率分布函数θ和φ,求取语义影响力SI(semantic influence,SI)作为特征词的权重,该改进算法记作SI-TFIDF(semantic influence-term frequency inverse document frequency,SI-TFIDF)。将SI-TFIDF算法与传统的TFIDF算法在sougou的数据库进行特征词提取,并采用K-means算进行聚类,对比结果显示,采用SI-TFIDF算法提取的特征词聚类效果优于TFIDF,验证了所提出方法的可靠性。在95598投诉工单上进行仿真实验,SI-TFIDF算法的投诉工单聚类准确率高于传统的TFIDF算法,验证了SI-TFIDF更适用于处理工单投诉的分类研究。     

螺母与钢,镀锌和镀铝薄板凸焊的研究

本文根据机械标准件行业新开发的焊接螺母技术要求,先后对DIN928方形螺母、DIN929六角形螺母与厚度0.5～4mm钢板,0.5～2mm镀锌和镀铝薄板进行了凸焊性能试验研究。试验结果表明,凸焊工艺稳定,凸焊接头质量良好。接头的抗扭强度达到和超过了DIN928,DTN929标准。从系列试验中获得了最佳凸焊工艺规范和技术措施。     

水溶性半无机硅钢片漆的涂漆工艺研究

分析了水溶性半无机漆的工艺特性及对涂漆工艺的影响因素，并在大量的工艺试验基础上，提出了在生产上切实可行的工艺。