利用六序分量复合序网法分析同杆双回线断线故障的新方法

本文结合双回线的特点，引入了六序故障分量，推导出同杆双回线各种断线故障的六序分量解析表达式，由此提出了六序复合序网分析双回线断线故障的新方法，此方法在分析双回线的断线时非常简单，并且六序故障分量之间的相位关系和幅值关系在复合序网中直观地表现出来，通过EMTP仿真计算证明了本文所提方法的正确性。     

锌锰纸板电池浆层纸的测定

本文根据浆层纸在干电池中的作用和对其性能要求,在我们长期实践和探索的基础上,参照国内外纸类取样和检验方法,提出评价浆层纸理化性能优劣的项目,并介绍了取样、试样处理和检测方法。     

硅碳自悬浮体的正负触变性

对硅碳白悬浮体做了系统工作。在含量较少的情况下呈牛顿型。含量达到一定程度后,产生三维结构,出现塑性体系。产生结构的固体含量与 PH 值有关。实验证明,在等电点(i,e,p.)附近结构最松驰。研究了水解聚丙烯酰胺(HPAM)对悬浮体的影响,发观在体系里的 HPAM 性能起主导作用,并破坏了原来硅碳白聚集体结构,呈絮凝体结构,并出现触变性。当高聚物在固体表面上一半时,具有最大动切力,即机械强度最高。同时产生最大触变性。聚丙烯酰胺的水解度较大时,体系出现了负触变性。     

非对称液压缸力控系统的优化设计

提出了用合理选择供油压力和正开口阀的办法,来克服负载流量在正、反向运动时不连续的问题,以使正、反向上的流量增益保持相等。并总结出了非对称油缸的设计步骤。还导出了伺服阀零位系数的极值,为分析系统静动态性能提供了参考。     

高性能自起动钕铁硼永磁同步电动机

在同步电动机中采用了高性能钕铁硼永磁材料后,其效率和功率因数比异步电动机有较大提高,但是也给这种电机的设计计算、起动性能以及电机的结构工艺等方面带来新的问题。本文在研制这种电机的基础上对上述问题进行了探讨,并介绍了一种新型转子结构,提出了解决起动难题而采取的一些措施。     

用于渗透蒸发的多层复合膜的研究

本文讨论了渗透蒸发多层复合膜的膜材料的选择及其制作方法,并对渗透蒸发膜的发展趋势作了予测。     

磨合过程中表面形貌变化的分形表征

磨合是各运动副在投入运行前为获得好的配合性、提高承载能力所必须经历的过程,表面形貌的明显变化是磨合过程中表现出的重要特征。本文引入分形理论,用分形参数表征磨合表面的形貌变化。研究表明,磨合表面变化的分形参数表征是简单有效的。     

Structure and tribological property of B2-based approximants

The present paper is concerned with a special group of approximants with B2 superstructures. In the first part, recent work on structural features of the B2 superstructure approximants is summarized. Experimental results obtained in Al-Cu-Mn and Al-Cu systems are presented, where a series of B2-based approximants are observed. These phases all have similar valence electron concentrations, in full support of thee/a-constant definition of approximants. Special emphasis is laid on the chemical twinning modes of the B2 basic structure in relation to the Al-Cu approximants. It is revealed that the B2 twinning mode responsible for the formation of local pentagonal atomic arrangements is of 180°/[111] type. This is also the origin of 5-fold twinning of the B2 phase on quasicrystal surfaces. Crystallographic features of phases B2, τ2, τ3,γ, and other newly discovered phases are also discussed. In all these phases, local pentagonal configurations are revealed. In the second part, dry tribological properties of some AlCuFe samples containing the B2-type phases are presented. The results indicated that the B2 phase having their valence ratio near that of the quasicrystal possesses low friction coefficient under various loads, comparable with the annealed quasicrystalline ingot. Such a result indicates that the B2-type phase withe/a near that of quasicrystal is indeed an approximant, which is in full support of the valence electron criterion for approximants.     

Electrostatic airborne ultrasonic transducers: modeling and characterization

An a priori theoretical model for electrostatic airborne ultrasonic transducers has been developed. The historical development of transducer modeling is briefly reviewed. This paper applies the plate-on-air-spring model to establish a mathematical formulation for the transducer behavior in terms of the characterized impedance parameters. It is clarified that such an electrostatic transducer is a capacitive-type device and obeys the reciprocity principle in the same way as a piezoelectric device. The accurate prediction of multiple resonant frequencies and transmitting responses for a typical V-grooved backplate transducer serve to substantiate the theoretical model.     

采用分布式实时操作系统的容错系统的设计与实现

介绍了设计和实现的一个分布式容错系统的实验原型。系统采用ＰＣ双机备份结构和ＱＮＸ分布式实时操作系统,通过用监视器进程定时检测工作节点状态和主机和备份机相互切换的方式,实现对单节点静默失效和偶发故障的实时容错。由于系统的容错功能是采用软件方式实现,使得该系统不仅开发成本低,而且功能易于扩充和升级。