根据高压电器设备的工况环境,设计了一种铁基合金粉末,其成分为:Cr 18％, Si 2.0％,B 3.0％, Ni 5％,C 2.0％, Nb 0.6％,Fe余量.采用等离子熔覆技术在16Mn钢表面制得铁基合金熔覆层.采用光学显微镜(OM)、扫描电镜(SEM)、电子探针(EMPA)和X射线衍射仪(XRD)分析了等离子熔覆层的组织结构和成分,并进行了摩擦磨损试验.结果 表明,所得等离子熔覆合金层非常致密,主要由γ-(Fe,Ni)、((Fe,Cr)7(C,B)3和Fe3Ni2相组成,具备良好的耐磨性.

A Fast method for measuring the scattering parameters of microwave two-port reciprocal devices is presented in this paper. The method solves the problem of inconsistency between the port of device under test (DUT) and the interface of the vector network analyzer (VNA) by cascading two reciprocal transitions on the two ports of DUT. According to the cascading characteristics of the microwave network, the scattering parameters of the transition and DUT are obtained sequentially by using MATLAB program.

为提高三坐标测量机在测量一种U型截面薄壁件时的测量精度,分别从温度和测量力两方面研究精度优化方法.基于物体热膨胀效应的原子热振动原理分析铝合金材料的热膨胀影响因素,将温度影响引入测量能力评估算法,得到可实施温度补偿的边界条件,利用Minitab对变温测量实验数据进行分析并拟合出该薄壁件在径向方向上的热膨胀函数,实现在温度边界范围内对测量结果进行精度优化;针对RDS XXT测头系统的内部构造,通过对测头结构进行力学分析并建立采点触发力学模型,确定该测头系统的采点触发模式为力矩触发,利用材料力学理论分析力矩触发模式下的被测件形变机理.测力及测量截面位置交叉测量实验结果表明:测杆长度越长,测力越小,且越靠近工件底部,测量误差越小,测量精度越高.

To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply.

To improve the formability of aluminum alloy, a new forming technique-the preform annealing process is proposed. Based on the mechanical properties of the original aluminum alloy AA5182-O with two experienced preforming annealing treatment, and preforming annealing process of a complex geometric shape aluminum door inner panel was numerical simulated by using LS-DYNA software. As a result, the effects of annealing time at 365°C on stamping height of the panel and the optimum annealing time were obtained. The results showed that the preform annealing process was feasible in the door inner panel. At 365°C, the smooth forming of the door inner panel was achieved after annealing for 20s with the pre-deformation amount 97mm, Which are the most suitable parameters.

Gas bulging with local-stretching preforming is presented to form titanium alloy tubular part with small radius. In ordinary gas bulging process, local thinning occurs at the corners with small radius and produces dangerous position of the component. In the paper, a preforming process so-called local-stretching is applied before gas bulging. Finite element simulation and experiments were carried out to verify the effectiveness of the preforming and gas bulging process for the tubular component of titanium alloy TA15. During the local-stretching preforming, the material near the corner was kept almost rigid, but the material far away from the corner experienced stretching deformation and thickness thinning. Then, during gas bulging, the material near the corner experienced thinning deformation. So, the thickness uniformity of the final component was improved effectively.