空调永磁同步电机轴电压原理及对策

随着永磁同步电机在空调系统应用越来越广泛,轴电压的问题不但影响电机本身的噪音及安全稳定性,而且对整个空调系统都会带来危害.本文采用建模的方法对常见空调系统里的永磁同步电机轴电压产生的原理进行理论分析,并结合实例分析轴电压的预防和防治.     

多台阶涡轮轴三辊斜轧减径量对轧制过程的影响规律研究

运用Simufact有限元软件建立了三辊斜轧两道次成形多台阶涡轮轴的仿真模型, 通过数值模拟分析了涡轮轴成形情况, 探究了减径量对轧制过程中轧制力、等效应力-应变以及外圆度误差的影响规律. 结果表明: 随减径量的增大, 轧件第1道次和第2道次的径向载荷、等效应力、等效应变和外圆度误差均呈增大趋势. 综合比较3种方案下的轧件成形情况, 方案2为最佳的道次减径量分配方案, 即第1道次减径6mm, 第2道次各台阶减径量分别为2、9和14mm.     

An estimation method of bearing strength of bolted joints in fibre reinforced composite

Some researchers have estimated the strength of bolted joints in fibre reinforced composite, using simple and efficient engineering procedures. However, for these procedures the effect of clamping due to the strength of bolted joints is not considered. In this paper, a method is presented for predicating critical bearing strength of single-hole bolted joints in composite on the basis of observing and analysing the results of experiments. The clamping effect of bolts is considered. The calculated results correspond to the test data on Glaphic/Epoxy laminates.     

钢丝软轴抗扭刚度的计算及测量

根据钢丝软轴基本参数的变化,确定其受载后其它几何尺寸的变化量,由此导出软轴两端相对扭转角进而得到钢丝软轴抗扭刚度的计算公式,此外,笔还在扭转试验机上对钢丝软轴的抗扭刚度进行实验测量,结果证实本理论计算值吻合于实际测量值。     

基于PCI总线的单圈绝对式光电轴角编码器实时数据采集系统

介绍了一种针对单圈绝对式光电轴角编码器而设计的基于PCI总线的实时数据采集系统.该系统以PLX公司开发且服从PCI2.1协议的PCI9052为接口芯片,利用功能强大的CPLD作为控制单元.采用TI公司生产的高性能A/D器件ADS803E作为核心器件对线阵CCD输出的信号进行实时采集,并给出了板卡调试方法和如何用合适的驱动程序开发工具编写驱动程序.实验证明,该采集卡满足单圈绝对式光电轴角编码器数据采集的需要.     

花键轴冷挤压成形后的三维光塑性模拟研究

本文利用光塑性方法,以聚碳酸酯（Ｐｏｌｙｃａｒｂｏｎａｔｅ）为材料研究了矩形花键轴冷挤压成形过程,获得了花键挤压成形的三维塑性应变场分布,提出其变形的应变分布特征,并对典型截面的应变进行了计算分析;文中还通过对聚碳酸酯材料的实验,得到了使花键齿形充满的最佳坯料尺寸,为实际工艺生产优选出合理的工艺参数。     

Immobilization of cytochrome P-450 and electrochemical control of its activity

P-450_cam (camphor-induced cytochrome P-450) was immobilized on an indium tin oxide (ITO) electrode by polypyrrole and its activity was controlled electrochemically. The results showed that P-450_cam was immobilized on the ITO electrode without denaturing and the amount of P-450_cam could be easily controlled. When, the electric potential was swept repeatedly between 0.4 and 0 V, the remarkable decrease of oxygen in the reaction mixture solution was observed only in the presence of camphor. In addition, hydroxycamphor was detected only in the same system by means of gas chromatography/mass spectroscopy. These results suggested that immobilized P-450_cam catalyzed the hydroxylation of camphor by the supply of electron from the electrode. The effect of pH and ionic strength on the activity was examined, and it was found that the high activity expressed at the pH of 6.0 – 7.0 and KCl concentration of 0.1 – 0.2 M . The paper is the first report that P-450 enzyme activity could be controlled artificially. © 1998 John Wiley & Sons, Ltd.     

一种多馈源转位机构的设计

通过某型雷达馈源转台中槽轮机构的设计和分析,并附加凸轮带动销轴等辅助定位装置,实现多馈源旋转转换工作和精确定位,满足总体设计要求。     

Inverse problem of fracture mechanics for a disk fitted onto a rotating shaft

A plane problem of fracture mechanics for a circular disk fitted onto a rotating shaft is considered. The disk is assumed to be fitted tightly onto the shaft, and there are N randomly located straight-line cracks of length 2l_k (k = 1, 2, ..., N) near the inner surface of the disk. The interference between the disk and the rotating shaft, providing minimization of fracture parameters (stress intensity factor) of the disk, is theoretically studied on the basis of the minimax criterion. A closed system of algebraic equations is constructed, which allows the problem of optimal design to be solved. A simplified method of minimization of disk fracture parameters is considered. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 4, pp. 201–209, July–August, 2009.     

AutoCAD在机械设计基础中的应用

本文结合机电专业机械设计基础课程的教学特点，将AutoCAD引入课程的设计教学中。这将有益于该课程教学质量的进一步提高。