CONTEXTUALIZING LEARNING OBJECTS USING ONTOLOGIES

Educational research over the past three years has intensified such that the context of learning resources needs to be properly modeled. Many researchers have described and even mandated the use of ontologies in the research being conducted, yet the process of actually connecting one or more ontologies to a learning object has not been extensively discussed. This paper describes a practical model for associating multiple ontologies with learning objects while making full use of the IEEE LOM specification. The model categorizes these ontologies according to five major categories of context based on the most popular fields of study actively being pursued by the educational research community: Thematic context, Pedagogical context, Learner context, Organizational context, and Historical/Statistical context.     

复杂电器产品快速设计与制造工艺研究

针对电器行业的复杂产品 ,研究了其基于LOM原型的产品/模具快速设计与制造工艺 ,提出了该工艺存在的问题及其解决方法。以实际电器产品为例 ,介绍了LOM原型、硅胶模具、树脂样件的制作工艺流程     

个性化远程教学系统的模型研究

个性化远程教学系统是基于网络暨Internet技术的远程教学系统的最新发展。文章根据学习对象元和国际IEEEP1484LOM标准以及其他相关技术,提出了个性化远程教学系统的概念以及特征,并且依据NCEC项目实践,对于系统的层次模型、功能模型和数据模型进行了深刻的阐述与剖析。     

刀切型纸层叠快速原型系统切割机理研究

采用具有自适应转向能力的刀具取代激光切割,实现一种经济型快速原型制造系统。介绍了刀具结构,采用曳物线模型分析了刀尖运动及其轨迹的形状误差机理,提出消除误差的逐接点修正方法。在已开发的试验机上制作切割样件研究割缝形态尺寸,回归分析表明在正常切割深度范围内因割缝造成的尺寸误差不超过0.003 mm。实际制作显示用这种刀具实现纸的层叠快速原型制造系统具有实用价值。     

<Emphasis Type="Bold">Development of Divisional Parallel Scan Technology in Large-Scale Laminated Object Manufacturing</Emphasis>

Many technological difficulties exist in the field of rapid prototyping (RP) technology when making large-scale prototypes. The manufacturing efficiency is the main problem, and the process implemention and RP equipment also present difficulties. In this paper, the concept of divisional parallel scan is presented. Laminated object manufacturing (LOM) technology is used for the basic forming process and has been improved continuously through practice. Static divisional scan technology was also better developed to dynamic divisional scan technology, which can help in achieving the object of improving work efficiency and optimising design.     

Ceramic green tape extrusion for laminated object manufacturing

Al₂O₃ and SiC green tapes with 0.2 mm thickness used for LOM (laminated object manufacturing) were prepared from a 75 wt.% ceramic suspension in a LDPE based organic vehicle followed by extrusion. Rheological characterization of the alumina and SiC suspensions were studied. TG-DTA analysis was carried out in air and microstructures were examined by SEM.     

以LOM原型为基础的电铸载体选择

本文以LOM原型为基础，分别制作环氧树脂模型、硅胶模型、吸塑件模型石膏模型，并对这四种模型做电铸载体的可行性进行分析，在不影响电铸质量的前提下，根据不同结构特征可以选择合适的电铸载体。     

大型原型LOM工艺中热压工艺的分析及系统实现

分析、比较了LOM工艺中几种典型的热压方式 ,认为这几种方式都不适用于大型原型制造系统。在SSM -1 60 0大型快速成形系统的开发中 ,设计了具有弹性补偿功能的板式热压系统 ,解决了LOM工艺在制造大型原型时存在的热熔胶融化不均匀、涂敷纸粘结不可靠、零件开裂变形的问题 ;完成了热压系统的设计工作 ,并对设计中应注意的问题进行了讨论。通过实验与原热压系统的成形效果进行对比 ,新系统明显提高了成形质量     

基于新LOM的金属功能零件分层快速制造研究

基于新LOM方法和热扩散工艺，以1.0mm数量级的不锈钢板做造型材料，尝试了金属功能零件的分层快速制造，介绍了新LOM方法的原理，进行了金属分层板的连接实验和样模制作。研究结果表明，新LOM方法加工的零件曲面光滑，没有明显的台阶效应；热扩散焊在堆积成形方向上尺寸变化小，且为系统误差，结合强度达到100MPa；零件最大综合制造误差为0.485mm，但大部分位置处的误差在0.3mm以下。     

快速原型技术现状与发展趋势研究

该文简要介绍了快速原型技术的原理、快速原型技术的特点,阐述了国内外现状及发展趋势。