Micromagnetic simulation on the dynamic susceptibility spectra of cobalt nanowires arrays: the effect of magnetostatic interaction

<正>Micromagnetic simulations have been performed to obtain the dynamic susceptibility spectra of 4×4 cobalt nanowire arrays with different spatial configurations and geometries.The susceptibility spectra of isolated wires have also been simulated for comparison purposes.It is found that the susceptibility spectrum of nanowire array bears a lot of similarities to that of an isolated wire,such as the occurrences of the edge mode and the bulk resonance mode. The simulation results also reveal that the susceptibility spectrum of nanowire array behaves like that of single isolated wire as the interwire distance grows to an extent,which is believed due to the decrease of magnetostatic interaction among nanowires,and can be further confirmed by the static magnetic hysteresis simulations.In comparison with single nanowire,magnetostatic interaction may increase or decrease the resonance frequencies of nanowire arrays assuming a certain interwire distance when the length of array increases.Our simulation results are also analysed by employing the Kittel equation and recent theoretical studies.     

测定氘核結合能的方法

本实驗所用的器材:碘化鈉晶体的閃爍譜仪,中子源,水或石蜡。当热中子被水或石蜡中的氫俘获,立即輻射γ光子,測量γ光子的能量,即得氘核的結合能。兰埃(Lea)最先观測到中子俘获γ射綫。他用Ra-Be中子源和探測γ輻射的盖革計数管观測到中子被氫俘获而产生的γ輻射。由于     

形变过程内耗

形变过程内耗是在生形变进行过程中测出的内耗，文章介绍了形变过程内耗的测量方法和目前人们对这种内耗的实验规律和微观体制的认识以及它可能提供的关于形变微观过程的知识。     

一种提高基于循环频移器的多载波光源光信噪比的方案

频率锁定多载波光源是实现太比特系统传输的关键器件之一, 目前已成为光纤通信领域的研究热点.基于循环频移技术产生的频率锁定 多载波光源因具有驱动电压低、串扰小、平坦度高的优点而受到重视, 但是其输出质量容易受到调制器固有的高阶谐波串扰的影响,特别是三阶谐波串扰. 为了减小三阶串扰的影响,本文提出了在I/Q调制器两支路上再加载另一频率为3f_m的射频信号的方案, 用其产生的一阶信号来抑制三阶串扰.通过理论分析与数值仿真,得到了载波数为24、 载波间最大功率差小于0.1 dB的多载波光源输出.与未采用三阶串扰抑制方案的结果比较, 光源输出有效光信噪比提高了2 dB. 结果表明,采用本文的改进方案,可以有效地提高多载波光源的输出平坦度和有效光信噪比.