Mechanical,forming and biological properties of Ti-Fe-Zr-Y alloys prepared by 3D printing

Biomedical Ti-Fe-Zr-Y alloys were prepared by 3D printing on pure titanium substrate. The influences of Zr on mechanical, forming, and biological properties of the alloys were investigated in detail. The results showed that with increasing the Zr addition, the surface roughness, friction coefficient and worn volume decrease at first and then increase, the lowest values obtained at 5.86 at.% Zr addition. The ultimate compression stress and specific strength gradually decrease. The studied alloys have no cytotoxicity. They can promote the early adhesion and proliferation of cells. The eutectic alloy with 5.86 at.% Zr addition has the best ability of apatite deposition, it exhibits a better comprehensive performance among the studied alloys, which is superior to the Ti_70.5Fe_29.5 and Ti-6Al-4 V alloys.     

Influence of cerium content on the corrosion behavior of Al-Co-Ce amorphous alloys in 0.6 M NaCl solution

The effect of cerium content on the corrosion behavior of Al-Co-Ce amorphous alloys in 0.6 M NaCl solution was investigated by cyclic polarization, Mott-Schottky and X-ray photoelectron spectroscopy techniques. Results indicated that the open circuit potential of Al-Co-Ce amorphous alloys displayed a decreased tendency with the increase in Ce content, and the amorphous alloy with 4 at.% Ce presented both the lowest passive current density and donor density indicating the best corrosion resistance, while adding excess Ce led to the reduced corrosion resistance of Al-Co-Ce alloys. Furthermore, it was found that a low Ce content is beneficial to the formation of a more protective passive film on Al-Co-Ce amorphous alloys, and the corrosion inhibition reactions of Al-Co-Ce alloys in 0.6 M NaCl solution were changed with the increase in Ce content and the detailed reasons were discussed.     

无线自组网按需平面距离矢量路由协议研究

文章介绍了AdHoc网络中按需生成路由方式的典型协议——AODV路由协议,它是应用于无线网状网络（也称做无线mesh网络）中进行路由选择的路由协议,它能够实现单播和多播路由。本文从路由建立、路由维护方面介绍了该路由的组网过程。     

涡流空气分级机的分级效率与分级精度

分析常用于表达和评价涡流空气分级机性能的分级效率与分级精度定义,结合分级机的结构,研究分级效率与分级精度的主要影响因素。结果表明,分级轮转速、进口风速、进料速率、导流盘对分级效率和分级精度均有影响,应针对物料选用不同的参数。     

基于CATIA的飞机钣金结构特征参数化设计系统

提出了飞机钣金结构特征参数化设计系统的体系框架;构建了由特征参数库和特征模板库组成的飞机钣金结构特征数据库。通过CATIA提供的数据输入接口和功能构件开发了设计系统,实现了飞机钣金结构特征的参数化三维建模。工程应用实例表明,设计系统在飞机钣金结构设计中提高了设计质量和设计效率。     

涡流空气分级机转速特性研究

通过试验,对影响涡流分级机性能的主要因素——转速进行了研究。发现随着转速的增加,分级粒径变小,分级效率先增加后减小。试验数据的分析结果表明,不同的物料对设备的要求是不一样的,同一参数对不同物料的影响也是不一样的。因而在设备的结构设计上,要根据不同的物料特性做出相应的调整。通过理论推导,得到了与试验结果一致的结论。利用流体力学计算软件进行了数值模拟,得到涡流分级机随着转速的增加,流场的涡流现象增强,当转速增加到一定的程度时,出现了反流现象,使已经分离出的细粒又返回到分级区,从而影响分级机的分级效率。     

基于车铣复合的闭式叶轮加工研究

针对闭式叶轮,提出了叶轮建模和车铣复合加工工艺方法,利用UG软件编制了数控加工程序,开发了基于VC的数控机床后置处理器,利用VERICUT软件进行仿真加工,最后经过实例加工证明了方法的可行性和正确性.     

RTM成型过程中树脂/纤维界面性能表征及分析

通过测试树脂的表面张力、碳纤维的表面能以及树脂与纤维动态接触角来分析RTM成型过程中树脂/纤维界面性能,并对比分析了树脂对涂覆溶液定型剂前后的纤维浸润性能的影响。结果显示,随着温度升高,树脂表面张力降低,纤维的表面能升高,使得树脂/纤维的动态接触角变小,利于树脂浸润单丝纤维;树脂对涂覆溶液定型剂后的碳纤维织物浸润较为困难。