薄壁零件高速铣削加工变形模型及变形规律研究

针对集中载荷作用下薄壁零件(两邻边固定、两邻边自由的矩形)的变形问题建立静态铣削力模型。利用ANSYS 14.0有限元软件进行仿真加工,研究了铝合金薄壁件在数控铣削过程中切削力不变时,零件在长度和高度方向的变形情况以及不同铣削力对变形的影响。得出薄壁零件在顺铣过程中的变形规律并提出了预防措施。     

Fault Prediction Based on the Kernel Function for Ribbon Wireless Sensor Networks

There exist several applications of wireless sensor networks in which the reliable operation can be crucial. Fault prediction is a critical problem in reliability theory for ribbon wireless sensor networks (RWSNs). Accurate fault prediction can effectively improve the availability of the WSNs system. In this paper, we evaluated the network performance for RWSNs, studied the basic theory of kernel functions, proposed a new failure prediction method based on kernel function, and selected the radial basis function as kernel function failure prediction models from two aspects of node hardware failures and network failures for fault prediction. Theoretical evidence and experimental results have shown that the proposed algorithmic prediction method has higher accuracy of 12 and 15% than that of GRNN and PNN respectively. Finally, we provided extensive numerical results to demonstrate the usage and efficiency of the proposed algorithms and complement our theoretical analysis.     

Modeling of Naval Vessels Combat System based on Complex Network

Naval Vessels Combat System is a kind of complex system.The modeling of combat system has become hot issues in the past years.This paper proposed a new method to establish models of combat system based on the theory of Complex Network.The method of modeling considered the operational entities as nodes.It considered flow of information,substance and energy as edges in a network.The research also carries on a simulation to prove the applicability.Ultimately,the paper concluded that this method is applicable and accurate.     

基于智能视觉的电机自动控制仿真

工业自动化水平的发展对电机使用提出更高要求,为提高电机控制精度与平稳性,提出基于智能视觉的电机自动控制研究.选取智能视觉系统光源与照明技术,设置采集流程;通过阈值分割,使目标与背景有效分离,确立旋转与平移矩阵,计算相机标定的内外参数,校正畸变图像;将处理后的图像信息作为控制依据,结合电压、磁链与运动方程构建电机数学模型;分析定子电压向量对电机转矩与磁链造成的影响,在固定周期内将电压向量划分为不同区域,根据转矩变大变小的不同需求,选择恰当的电压向量来改变磁链幅值与旋转角度,达到电机自动控制目的.仿真结果表明,所提方法的电机控制信号更加平稳,同时控制精度高,改善作业效果.     

VEST: Abstract vector calculus simplification in Mathematica

We present a new package, VEST (Vector Einstein Summation Tools), that performs abstract vector calculus computations in Mathematica. Through the use of index notation, VEST is able to reduce three-dimensional scalar and vector expressions of a very general type to a well defined standard form. In addition, utilizing properties of the Levi-Civita symbol, the program can derive types of multi-term vector identities that are not recognized by reduction, subsequently applying these to simplify large expressions. In a companion paper Burby et al. (2013)  [12], we employ VEST in the automation of the calculation of high-order Lagrangians for the single particle guiding center system in plasma physics, a computation which illustrates its ability to handle very large expressions. VEST has been designed to be simple and intuitive to use, both for basic checking of work and more involved computations.     

Impedance spectroscopy analysis of CeNbO4.25

Monoclinic CeNbO4.25 was prepared by solid state reaction. Complex impedance analysis indicated the presence of grain interior effect along with the grain boundary contribution. The values of ionic tra...     

High value polyurethane resins from rubber seed oil

Rubber seed oil having high free fatty acid content and high unsaturation was used to obtain high quality polyurethane resins through epoxidation and ring opening with methanol and free fatty acids. Two polyols prepared with free fatty acids and without were cured with modified methylene diphenyl diisocyanate to obtain strong, high modulus glassy polyurethanes. The effect of structure on thermal and mechanical properties was analyzed. This showed that the polyol with free fatty acid utilized to obtain a branched structure gave superior crosslinking density and mechanical properties. © 2016 Society of Chemical Industry