Fabrication and Mossbauer Study of FeCo Alloy Nanotube Array

Arrays of FeCo nanotubes are fabricated in the pores of porous anodic aluminium oxide templates. Transmission electron microscopic result shows that the nanotubes are regular and uniform. Magnetic hysteresis loops measured at room temperature are different from those of nanowires with the same composition, which are caused by the unique shape of nanotubes. The M6ssbauer spectra show that the hyperfine field is smaller than that of the bulk＇s and increases with decrease of measuring temperature. However, the areas of the doublets appeared in M6ssbauer spectra decrease with decrease of measuring temperature.     

一种嵌入式低功耗高精度带隙基准的设计

提出了一种自偏置,共源共栅(Cascode)结构的标准CMOS带隙基准电路,未使用运算放大器,占用面积小,功耗低,有利于集成到低功耗电路系统.采用新颖的Power On Reset 电路解决了自偏置电路的启动问题.采用基极电流消除技术和基极电阻补偿技术实现高精度.在UMC 0.25 μm 3.3 V电源电压CMOS工艺条件下进行模拟验证,模拟结果表明:带隙基准输出电压为1.208 3 V,在-20～80 ℃温度范围内,温度系数为8×10-6/℃,电源抑制比(PSRR)为-65.8 dB,功耗小于200 μW,输出噪声225 nV/Hz.     

Influence of shape anisotropy on microwave complex permeability in carbonyl iron flakes/epoxy resin composites

To explore the mechanism of carbonyl iron flake composites for microwave complex permeability, this paper investigates the feature of the flakes. The shape anisotropy was certified by the results of the magnetization hysteresis loops and the Mossbauer spectra. Furthermore, the shape anisotropy was used to explain the origin of composite microwave performance, and the calculated results agree with the experiment. It is believed that the shape anisotropy dominates microwave complex permeability, and the natural resonance plays main role in flake.     

双主相工艺制备烧结Nd-Fe-B基永磁体的研究进展

双主相工艺是近年提出的改善Nd-Fe-B基烧结磁体性能的有效途径。该工艺通过对Nd-Fe-B和（Nd,Re）-Fe-B两种粉末的成分设计,使磁体形成一种双主相结构,优化晶界相成分及分布,显著提升矫顽力。特别是对高丰度铈（Ce）磁体、混合（MM）稀土磁体,可以有效地抑制由于低各向异性场相铈铁硼（Ce-Fe-B）、镧铁硼（La-Fe-B）等的引入引起的矫顽力降低的问题。同时,对于重稀土（Dy/Tb）磁体,在相同矫顽力提升的情况下,双主相法对比传统单主相法所需的重稀土含量更低。本文详细阐述了通过双主相工艺制备磁体的性能改善及相关机制,为制备高性能稀土磁体提供思路及支撑。     

无线网络技术在通信系统中的应用

结合通信系统和无线网络技术内涵,针对提高无线网络技术在通信系统中的应用水平提出了误码和数据丢失改进、延迟改进等相关改进措施.