Effect of deposit conditions on magnetic parameters of electroless CoFeB films

Electroless CoFeB films with soft magnetic characteristics were fabricated on poly-ester plastic substrate using sodium tetrahydroborate (NaBH₄) as reducer. The change of film composition corresponding to magnetic characteristics was dependent on deposition conditions. As the concentration of NaBH₄ and bath pH increase, the surface roughness of films reduces approximately from 160 to 137 nm. The soft magnetic film exhibited large saturation magnetization of 145 emμ/cc and low coercivity of about 7.6 Oe. Low boron content in film was found resulting in higher coercivity. At 2 GHz, the real permeability and imaginary permeability of films are respectively 275 and 141 as the concentration of reducer is 0.066 mol/L. Hysteresis loops of films show a remanence close to the saturation magnetization and along the hard axis display anisotropic field of 75 Oe.     

输电线路检修计划的优化算法综述

目前人工编制检修计划的方法,无法综合考虑输电线路检修的可靠性和经济性,而优化算法可以实现两者的平衡。该文综述了国内外输电线路检修计划优化算法的研究现状,介绍了该算法的两种类型即输电与发电联合和输电线路单独编制检修计划的优化算法。前者重点介绍了基于Benders分解的算法和灵敏度分析法,后者主要有基于Benders分解和基于可靠性评估的两种算法。对四种算法分析比较后,提出今后的研究方向应为从实用化的角度改进算法的计算效率和收敛性。     

Low-Complexity DOA Estimation Based on Constraint Solution Space

The Weighted Subspace Fitting (WSF) algorithm is one of the universal algorithms in Direction-Of-Arrival (DOA) estimation, which is of high accuracy. However, it involves the multi-dimensional nonlinear optimization problem, and the computational complexity is usually high. In this paper, we propose a low-complexity DOA estimation algorithm based on constraint solution space. Firstly, we use ESPRIT algorithm to limit the solution space around the best solution and reduce the computational range. Then, we find the best solution in a smaller solution space constraint by Cramr-Rao Bound (CRB), and seek repeatedly until reaching the global optimal solution of WSF algorithm by using the space of the best solution. By limiting the searching process in smaller solution space, this strategy controls the direction of convergence and reduces computational complexity. The experimental results show that this algorithm needs less iterations when the same DOA accuracy is required, and the computational complexity is apparently reduced.