Preparation of lithium specimens for transmission electron microscopy

A method of preparing undeformed thin lithium specimens for TEM is described. A solution of dehydrated methanol and toluene is used both for initial dishing of the foil by chemical polishing and also for final thinning. Under electron beam irradiation in the TEM, new pure Li crystals can grow out of the existing Li specimen. These in situ crystals can be used for the study of the microstructure and electronic structure of Li using TEM and electron energy loss spectrometry.     

Development and design of an active work piece holder driven by piezo actuators

The use of piezo actuators in machine tools is a current topic. There are many research works which show the advantages of this kind of actuators in various fields around machining. In this paper an active work piece holder is presented, which is designed for reducing the dynamic displacement between the tool and the work piece relatively. The paper shows the design process for the fixture, the finite element analysis of the mechanical parts and the actuators. Also a specially designed power amplifier is presented which fits best to the needs of voltage and frequency range of the active work piece holder. First experimental results are shown.     

石材开采爆破劈裂机理及新工艺与新药剂试验研究

本文对石材开采方法进行了分类,用模糊集合理论与方法进行了评定,指出我国石材开采技术发展的重点。著者提出了准静态劈裂成缝爆破的机理,将裂缝的形成分为开裂、扩展与止裂三个阶段,提出了各阶段的模型与判定条件算式。著者提出并试验研究了用半圆套管对成缝方向进行定向控制的新工艺。研制成开采石材荒料的新药剂。经实验室测定与四个采石矿的试用,获得满意效果。     

Ultrasonic measurement of contact stiffness and pressure distribution on spindle–holder taper interfaces

The measurement of contact characteristics of the spindle–holder taper interface is critical for the evaluation of the performance of a machine tool spindle system. In this study, an ultrasonic method was proposed to measure the contact stiffness and pressure distribution on the taper interface. The taper interface was scanned by an ultrasound transducer, and the nominal contact area was directly estimated from the resulting ultrasonic reflection coefficient. The normal stiffness distribution was determined by the spring-damper model from the reflection coefficient. On this basis, the distributed and global radial stiffness of the taper interface was calculated by the presented theoretical formulas. Meanwhile, a calibration curve was established to convert the ultrasonic reflection to contact pressure. Based on the proposed ultrasonic method, the effects of angle fitting error and clamping force were studied. The results show that the contact area, contact pressure and contact stiffness increase with the clamping force. As the angle fitting error increases, the contact area decreases, while the pressure and stiffness at the big end of the taper interface become much larger than these at the small end. In the meantime, the global radial stiffness increases first and then decreases. This result suggests that a larger angle fit error within the permissible range is better for the global radial stiffness. Moreover, the measured results confirm that a taper joint with an angle fit error larger than +36" is not suitable for practical application, because the contact pressure at the small end is too small. To compare with the ultrasonic method, the geometrical shape profiles of the contact surfaces were constructed, and FE models were also established for contact pressure predictions. The comparison shows that the ultrasound results are consistent with the surface shape profiles and the numerical predictions. Besides, one of the taper interfaces was measured three times with the same clamping force, and the results indicate that the repeatability of the proposed method is good.     

压边力对IF钢极限拉深比的影响

采用拉深试验方法对IF钢进行了不同压边力下的拉深试验,探讨了极限拉深比与压边力的关系,并得到了描述IF钢极限拉深比和压边力的数学关系式。研究认为,极限拉深比与压边力的关系可分为两个阶段,在第1阶段,随着极限拉深比的增大,压边力急剧下降;在第2阶段,随着极限拉深比的增大,压边力下降平缓,并逐渐趋于一定值。     

圆盘支架外壳多工位级进模设计

介绍了圆盘支架外壳结构与成形工艺,采用子模单元的多工位级进模结构替代原多副单工序模的冲压方式。通过实际生产表明,采用级进模生产汽车钣金结构件,降低了零件生产成本和工人劳动强度,提高了零件成形质量和生产效率,可为此类零件的冲压生产提供参考。     

汽车铝板顶盖成形回弹优化的数值模拟研究

针对汽车铝板顶盖在冲压成形过程中容易出现回弹等问题,以某车型汽车铝板顶盖为例,采用Autoform软件对其冲压成形过程进行了仿真模拟,对比了采用不同拉深工艺零件成形结果。通过优化零件天窗区域的翻边工艺,零件成形回弹得到了控制。     

利用岩屑床破坏工具和可膨胀套管扶正器改善井眼质量

分析了影响斜井钻井安全、固井质量等影响井眼质量的主要原因;介绍了国内外岩屑床破坏工具和可膨胀套管扶正器的研发和室内试验、现场应用情况;提出了适用于斜井、水平井固井用岩屑床破坏工具和新型可膨胀套管扶正器的发展方向和建议。     

10000m^3低压瓦斯气柜的腐蚀与防护

根据近年来瓦斯气柜多次发生泄漏事故,分析其腐蚀特点并采取有效措施加以防护.     

对刚性引锭杆及其存放装置的改进设计

根据刚性引锭杆及其存放装置所存在的问题，通过理论分析和实际使用的摸索，提出了改进设计的刚性引锭杆及其存放装置，经厂家采用，取得了良好的效果。