辽宁地区高速公路绿化树种选择的探讨

对辽宁地区高速公路绿化的特点及现状作了简要论述.通过对立地条件的分析,提出因地制宜,适地适树是高速公路绿化的前提.并对目前植物选择上存在的一些问题进行了探讨.     

舰艇编队网络化体系协同反导作战分析

文章介绍了舰艇编队协同反导作战系统的功能体系结构和系统各功能节点的关系,对系统三层网络结构和功能进行了探讨,分析了舰艇编队协同反导作战过程,阐明了舰艇编队网络化体系的作战优势和新的技术挑战。     

LXI总线接口在远程测试系统中的应用

简要分析了新一代仪器总线系统LXI（Lan eXtension for Instrument）的特征及其技术特点,重点对基于LXI总线的远程测试系统的构建技术进行了研究。     

七座小客车碰撞安全性的模拟与分析

采用有限元方法分析了七座小客车碰撞安全的特性,通过特殊焊接形式和约束的施加,建立了与实车相一致的悬架和轮胎模型。整车运用施加质量点等方法,有效地保证了整车模拟碰撞过程的准确性,并成功地完成了与实验结果的对标分析。     

小半径曲线双层桁架桥设计研究

随着国内桥梁大规模建设,双层桁架桥梁逐渐增多,直线钢桁结构的设计与应用较为成熟,曲线桁架结构的研究较少。依托贵阳市人民大道筑城广场大桥,研究了小半径曲线桁架桥的合理构造布置,通过Midas Civil进行结构整体受力分析,采用ANSYS对关键节点受力性能进行研究,为小半径曲线双层桁架梁桥设计及施工提供可靠的理论和技术支持。     

Mesh motion approach based on spring analogy method for unstructured meshes

Mesh motion strategy is one of the key points in many fluid-structure interaction problems. One popular technique used to solve this problem is known as the spring analogy method. In this paper a new mesh update approach based on the spring analogy method is presented for the effective treatment of mesh moving boundary problems. The proposed mesh update technique is developed to avoid the generation of squashed invalid elements and maintain mesh quality by considering each element shape and grid scale to th...     

Novel mesh technique and its application in the wind field simulation for flexible spatial structure

In this paper, novel mesh techniques are proposed for wind field simulation of flexible spatial structure. For mesh generation, an interpolation strategy is presented to obtain a mesh system with variable density. Two spatial structure examples are used to examine the efficiency and applicability of this technique. Then based on the structured mesh system generated by the technique, the mesh nodal coordinates are updated to adapt the moving boundary conditions by means of the mapping interpolation functions and some examples are given to verify the effectiveness. Furthermore, the constrained counterforce distribution technique and projection interpolation strategy are developed to implement the data exchange on the interaction surface of wind and structure. Finally, the computational accuracy is numerically validated.     

Histological changes following surgically-assisted rapid tooth movement through resistance reduction and distraction osteogenesis in dogs

Objective To investigate the histological changes of rapid tooth movement in dogs treated by resistance reduction and distraction osteogenesis, aiming to establish an animal model and further to reveal the remodeling mechanism of rapid tooth movement. Methods A total of 8 local hybrid dogs were selected as subjects for this study. The second pre-molar was extracted on both sides. The experimental side underwent alvelor surgery for resistance reduction and a home-made tooth-borne intraoral distraction device was installed for rapid tooth movement, while for the other side (control side) only tooth-borne intraoral distraction device was used for rapid tooth movement. The longest active force-delivery span was 2 weeks, followed by 6-week retention. The distance between the moved tooth and anchor unit was recorded weekly, and radiography was performed for each side before and after distraction. The surrounding tissues including periodontal ligament and alveolar bone were sectioned for histological analysis. Results The average distance of tooth movement was 3.55mm on the experimental side and 1.11mm on the control side. The rate of tooth movement was notably higher (P<0.01) and no significant apical root resorption was detected by X-ray on the experimental side. The active alvelor bone remodeling was found on the tension and pressure sides. However, there was no significant difference between the experimental side and the control side after the retention period. Conclusion The rate of orthodontic tooth movement can be accelerated through resistance reduction and periodontal distraction without any unfavorable effects but at minimal anchorage loss.     

车身连接点动刚度分析与NVH性能改进研究

提出了用有限元法进行车身连接点动刚度分析的方法和流程,比较了利用截断模型和整车模型进行动刚度分析的差异,叙述了FEA模型动态特性修改途径.对某一自主研发轻型客车车身进行模态试验并计算FEA与试验模态振型MAC值,验证了FEA模型的有效性,并利用该模型进行连接点动刚度分析和动态修改,取得了明显效果.