铝合金微弧氧化陶瓷层的耐磨性

应用微弧氧化这一高新表面改性技术在LY12铝合金表面形成陶瓷膜层,并对其在常温下的耐磨性能进行了对比测试与分析。实验结果表明,微弧氧化陶瓷膜层的表面磨损外观比较均匀,磨损痕迹也比较轻微,其表面硬度达到2500HV,是基体的10倍以上。由此可见,微弧氧化技术大大改善了铝合金表面耐磨特性和硬度。

     

影响区形状对砂井地基固结性状的影响

基于Deng等提出的砂井渗透系数随时间呈指数函数形式降低的假定,考虑了土体中的径-竖向渗流,推导建立了砂井地基的固结控制方程,并通过采用分离变量法求得了该方程的解析解。通过将该文退化解与已有的解析解及该文解析解与有限差分解分别进行对比,验证了该文解答的正确性。根据该文解答,分析了砂井地基的固结性状。分析表明,无论是否考虑竖向渗流,砂井地基的固结速率均随井阻因子2O接触角越小,其润湿性越高。分光光度计测试结果表明,经等离子体处理,ITO薄膜透过率较未处理均有所下降。四种工作气体下,等离子体处理压强越大对透过率的影响越小,但随着处理时间的增长影响会增大;相较其他工作气体,氧气等离子体处理整体变化最小。四点探针表征表明,处理后的ITO薄膜方块电阻无明显变化,这是由于等离子体处理只对ITO薄膜表面进行改性,没有改变内部性质。利用霍尔效应测量载流子浓度,没有发现明显变化,与方块电阻不变结论一致。     

O2,金属电极/YSZ界面的电化学研究

本文利用交流阻抗和直流极化的电化学方法，比较了200～500℃氧在Pt、Ag、Au、Ag－Pd四种化学镀电极上的扩散，350～600℃氧在金属电极／YSZ界面的电化学反应速度以及阴阳电荷传递系数；计算了350～600℃四种电极的界面阻抗；研究了400℃时O2在Ag－Pd电极界面的交换电流密度Io与氧分压Po2的定量关系．     

Progress in Thermal Contact Resistance

The developments of aeronautics and astronautics require engines of higher quality. The temperature distribution in combustion engine is highly influenced by the thermal conduct resistance. To predict the temperature field of the hot-end assemblies of combustion engine, the thermal contact resistance must be considered. The object of the study is to propose a model of high application including in conditions of high temperature and high pressure. Up to date, many models and empirical or semi-empirical corre...     

HULL GESTURE AND RESISTANCE PREDICTION OF HIGH-SPEED VESSELS

Since trim and sinkage are significant while vessels are advancing forward with high speed, the predicted vessel resistance based on restrained model theory or experiment may not be real resistance of vessels during voyage. It is necessary to take the influence of hull gesture into account for oredicting the resistance of high-speed ship. In the present work the resistance problem of high speed ship is treated with the viscous flow theory, and the dynamic mesh technique is adopted to coincide with variation of hull gesture of high speed vessel on voyage. The simulation of the models of S60 ship and a trimaran moving in towing tank with high speed are conducted by using the above theory and technique. The corresponding numerical results are in good agreement with the experimental data. It indicates that the resistance prediction for high speed vessels should take hull gesture into consideration and the dynamic mesh method proposed here is effective in calculating the resistance of high speed vessels.     

Plenary Session: The Operator's Reliability and Safety in Industry L'Homme Agent d'infiabilite et de Fiabilite du Processus Industriel

When we look at the course of development of world civilization, we can recognize that the speed of development is becoming faster and faster. The author tries to examine the possible danger of this accelerated speed or change and to explain Japan's high pitch development after the opening of her door to the western world about 100 years ago. Ho also explains how human factors studies have been developing in Japan and their significance with regard to social change. Concerning this rapidly changing world civilization, he discusses the mission of human factors research in the future and the ways to maintain humanity.     

Coating of TiB2 dispersed Ti50Ni50 superelastic alloy layer onto Ti-6Al-4V alloy by spark and resistance sintering

The spark and resistance sintering (SRS) of a mixture of Ti, Ni, and TiB₂ powders was carried out to form a TiB₂ dispersed TiNi alloy layer onto a Ti-6Al-4V alloy substrate. The strength and delamination resistance of the surface layer were evaluated by three-point bending tests. The results showed that the bending strength of the specimen with the TiNi alloy surface layer without TiB₂ particles sintered at 1273 K was low because the crack initiation occurred at an early stage of loading in a thick interface layer containing brittle Ti-Ti₂Ni eutectic. By decreasing the sintering temperature to 1200 K, the bending strength increased and the crack initiation occurred from the surface because the interface layer was thin and did not contain the brittle Ti-Ti₂Ni eutectic. For the specimens with TiB₂ dispersed TiNi surface layer that was sintered at 1273 K, the bending strength was larger than that of the specimens with TiNi surface layer because the interface layer does not contain the Ti-Ti₂Ni eutectic and compressive residual stress generated in the surface layer during cooling process after SRS suppresses the crack initiation on the surface. The coating of TiB₂ dispersed TiNi alloy onto titanium alloys by SRS provides strong interface to prevent delamination of the surface layer, strong surface due to residual compressive stress, and wear-resistant surface due to the existence of hard TiB₂ particles and superelastic deformation of TiNi matrix.