Strain rate sensitivity of tensile properties in high Nb containing TiAl alloys

The effect of strain rate on the yield strength of high Nb containing TiAl alloy was studied. The results show that the strain rate sensitivity varies with the test temperature, and the yield strength is not sensitive to the strain rate at room temperature but significantly sensitive to the strain rate at high temperature. An increase of the strain rate or a decrease of the temperature results in an obvious change of fracture mode. It is found that the strain rate sensitivity of this alloy varying with temperature is due to the dislocation climb generated at high temperature.     

理论模型在高质量、无缺陷铸坯生产中的应用

尽管连续铸钢技术已经在全世界广泛、成功地应用，然而通过现存所选择的工艺和设计参数来生产高质量产品还有一些障碍。近年来，通过冶金工作者的不断努力，取得了一些突破性成就。     

A refined beam theory based on the refined plate theory

Summary Based on the refined plate theory, a refined theory of rectangular beams is derived by using the Papkovich-Neuber solution and Lur’e method without ad hoc assumptions. It is shown that the displacements and stresses of the beam can be represented by the angle of rotation and the deflection of the neutral surface. The solutions based on the new theory are the same as the exact solutions of elasticity theory. In three examples it is shown that the new theory provides as good or better results than Levinson’s beam theory when compared to those obtained from the linear theory of elasticity.     

焚烧炉烟气中铅、锌、苯并(a)芘的测定

建立了用电感耦合等离子体光谱法(ICP-AES)和高效液相色谱法(HPLC)分别测定焚烧炉烟气中铅(Pb)、锌(Zn)和苯并(a)芘(BaP)的分析方法。研究了烟尘及玻璃纤维滤筒的预处理，测定Pb、Zn、BaP时基体的干扰与消除，并给出Pb、Zn的干扰校正系数。实验测得Pb、Zn和BaP的回收率超过84％，相对标准偏差Pb为3．51％，Zn为7．28%，BaP为4．30％。实验结果表明，该分析方法可以满足焚烧炉运行中的监测需要．     

Preparation and characterization of Ni/Co bimetallic nano-clusters

Ni/Co bimetallic nano-cluters have been prepared from the aqueous solution by reducing their corresponding metal salts under suitable conditions. The experimental conditions including the type and concentration of protective agent, feeding order and the pH of the solution that influence the average particle size have been studied in detail. Transmission electron microscopy (TEM) indicates that the shape of those bimetallic nano-cluster particles is spheroid. The alloy structure has been shown by X-ray powder diffraction (XRD). The X-ray photoelectron spectroscopic (XPS) data have confirmed that the nickel and cobalt in the bimetallic nano-clusters are in the zero-valence state.     

A novel drag test to evaluate media tribology design on head wear

 By changing the head's Z-height, a new accelerated drag test has been developed to characterize head wear under high interference conditions. Compared to contact start stop (CSS) and other drag tests, heads wear faster in our approach, due to the stressed condition at the tilted trailing edge. The optimized Z-height has been chosen so that the head-disk interference and acoustic emission are maximized. The wear volume can be estimated by optical microscopy. The influence of lube bonded ratio and X1P additive amount on head wear has been studied for AM3001 lubricant. Lower bonded ratio and higher X1P additive were found to give rise to less head wear, which is in agreement with the existing results of contact start-stop and other drag tests. In media manufacturing, tape burnish processes were found to significantly affect the bonded ratio in the AM3001/X1P lubricant system, which consequently affects head wear. Short tape burnish times were found to reduce the media's head wear. Received: 16 July 2002/Accepted: 23 October 2002 The authors would like to thank Dr. Ken E. Johnson for his extensive support in this project. Paper presented at the 13th Annual Symposium on Information Storage and Processing Systems, Santa Clara, CA, USA, 17–18 June, 2002     

Plasma Induced Degradation of Benzidine in Aqueous Solution

The degradation of benzidine in aqueous solution by the low temperature plasma was examined. The results showed that the concentration of medium and the value of pH have an appreciable effect on the degradation of benzidine. What is more important is that iron ions acting as a catalyst play an important role in this reaction. For exploring the degradation mechanism of benzidine, some of the intermediate products were recorded by HPLC (high performance liquid chromatography).     

基于数据库管理系统的电机设计集成系统软件开发

本文基于电机设计的基本原理 ,采用Access数据库管理技术、面向对象技术、SQL查询语言 ,利用VisualBasic 6.0为工具开发了基于数据库管理系统的电机设计集成系统软件。在实际使用中充分证明 ,该软件操作方便、运行良好、可维护性高 ,软件计算结果比较接近实验值。