Effects of Load Direction on Performance of Tiliting Pad Journal Bearings

At the previous works for tilting journal pad bearings （TPJBs）, most TPJBs are designed to operate with the load either directly on-pad（LOP） or directly between-pad（LBP）. However, in practice, in some cases, the load direction can change dramatically in operation. With the current requirements for the analysis of dynamic characteristics of the rotor-bearing systems, the effects of the load direction on the bearing performance must be known. So, in this paper, the effects of load direction on the static and dynamic characteristics of TPJBs are obtained with theoretical analysis based on the hydrodynamic lubrication theory, and the influence of load direction on the performance of TPJBs in different structure and operating parameters is also analysed. The results show that the load direction has considerable effects on the static and dynamic characteristics of the TPJBs, especially for the TPJBs that are operating under heavy load and high rotor speed. And for the operating condition that load direction changed rapidly, TPJBs with more pads, smaller length to diameter ratio, larger clearance ratio and smaller perload ratio can reduce the performance fluctuation with the variation of load direction.     

染料敏化太阳能电池对电极的研究进展

简要说明了染料敏化太阳能电池中对电极的作用,指出对电极是染料敏化太阳能电池的重要研究方向。详细介绍了各类对电极的特点和制备工艺,通过对比发现,铂对电极性能最好,但高成本限制了它的应用;价格低廉、性能较高的碳和聚合物对电极的发展前景广阔。最后论述了对电极的发展方向和国内外的研究现状。     

SiO2纳米复合稳定WO3薄膜气致变色特性研究

以钨粉为主要原料,采用过氧化法及提拉技术制备WO3薄膜,通过SiO2纳米颗粒复合改性提高了WO3薄膜的气致变色稳定性.测试并研究了SiO2复合掺杂对溶胶颗粒分布、气致变色稳定性等的影响,通过测试薄膜循环中红外振动吸收的演变,深入研究了SiO2纳米复合对WO3薄膜气致变色性能影响的内在机制.研究结果表明,SiO2的掺杂抑制了WO3薄膜内的共角聚合,将薄膜的致/褪色循环次数由20次提高到500次以上,WO3-SiO2复合薄膜的稳定网络结构是提高其气致变色循环稳定性的主要原因.     

一种实用的精密测量设备空气弹簧监控系统

介绍了典型空气弹簧系统的组成和原理.以此为基础,根据几何量精密测量的需要,研制了一种电子与机械相结合、安全可靠的空气弹簧自动监控系统.系统的关键部分包括气动升高安全控制机构和平台调平机构,基于计算机平台传感系统,信号分析处理和监测系统.该监控系统可直接用于大型高精度几何量测量设备(如激光干涉比长仪),实现仪器振动的隔离、自动调平、高度控制等功能.     

Preparation and Characterization of Fe3O4 Magnetic Nano-particles by 60Co γ-ray Irradiation

By using a new method, 60C0 γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM), respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation (10 kGy) is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation (10 kGy) are mainly in small cubic shape and the size uniformity of these particles is good.     

工业炸药有毒气体含量测定的影响因素

文章探讨了工业炸药爆炸后有毒气体测定过程中多种因素对测定结果的影响。试验表明,钢炮扩孔对有毒气体测定结果影响明显,随钢炮扩孔增大,有毒气体含量显著增大。当扩孔率为37%和95%时,有毒气体总量比新钢炮分别增大了24.5%和29.2%。起爆用雷管对低感度炸药有毒气体测定结果影响较显著,而对高感度炸药影响较小;用军用雷管起爆产生的有毒气体最少,而用煤矿许用瞬发电雷管起爆产生的有毒气体最多,并且膨化硝铵炸药有毒气体的增加(23.0%)大于粉状乳化炸药(10.8%)。石英砂用量对有毒气体测定结果也有明显影响。当石英砂完全覆盖药卷时,在一定范围内,增加石英砂用量导致有毒气体含量增大;当钢炮扩孔相当大时,增大石英砂用量使钢炮口全部覆盖严实,有毒气体含量减少。     

煤层顶板岩石强度的预测

将某勘探区已取得的煤层顶板岩样实验室分析结果与测井视电阻率进行回归,得出回归方程,进而将其运用到整个勘探区,预测出岩石强度的总体分布趋势,对矿井设计及安全生产有一定的指导意义。     

国内外聚丙烯催化剂的研究进展

综述了聚丙烯催化剂的发展历程及现状。针对国内外聚丙烯催化剂的催化特点,并根据市场对聚丙烯性能的要求,提出了聚丙烯催化剂的主要开发方向。     

PAN基原丝预氧丝炭纤维微结构的几种新的X射线衍射散射定量表征技术

介绍几种新近开发的针对PAN基原丝、预氧丝和炭丝微结构和结构缺陷的X射线衍射与散射定量表征技术,它们是:纤维材料中柱状(椭球状)纳米取向微孔体积分数X射线小角散射定量表征方法;纤维材料中柱状(椭球状)纳米取向微孔取向角的小角散射定量表征方法;预氧丝中链状相与环化相体积分数的小角衍射定量表征方法以及炭纤维中乱层石墨相与单层石墨相的X射线广角衍射定量表征方法等。     

钛合金的扩散焊连接技术

本文介绍了扩散焊的原理、特点和主要扩散焊方法,对其在钛合金材料中的应用研究现状进行了综述,并对钛合金扩散连接的应用前景进行了展望。