航空通信网络中复杂干扰过滤技术研究

航空通信环境中存在复杂的干扰信号,对正常的通信信号造成强烈的干扰。利用传统算法进行干扰信号过滤,无法避免由于干扰信号过于复杂导致过滤不充分的缺陷。提出一种基于加权残差优化算法的航空通信网络中复杂干扰过滤方法。对原始信号进行降频处理,能够消除峰值干扰信号,提高了信号的准确性。根据加权残差修正优化算法的相关原理,对通信信号进行残差优化处理,经过处理后的通信信号在受到干扰时会形成零陷,实现了对复杂干扰信号的过滤。实验结果表明,利用该算法进行航空通信网络中复杂干扰信号过滤,能够有效提高过滤的准确性,效果令人满意。     

The First-principles Study of Hydrogen Adsorption and Diffusion on the Biaxial Strained Fe(110) Surface

Hydrogen is known to play a negative role in mechanical properties of steel due to hydrogen embrittlement. Surface strain modifies the surface reactivity. In this paper, we employed spin-polarized periodic density functional to study the atomic H adsorption and diffusion on the biaxial strained Fe(110) surface. The result shows that the adsorption of H at the Tf site is the most stable on compressive surface and tensile surface. And H atom on the top site relaxes to Tf site on the strained surface. The adsorbed hydrogen atom at all calculated adsorption sites relaxes towards the surface due to the tensile strain. Lattice compression makes the bonding strength weaker between H atom and the surface. The analysis of the partial density of states shows that H 1 s orbital hybridizes with the Fe 4 s orbital. The result of charge density difference shows electrons are transferred from Fe to H atom. Compressive strain reduces the transferred electrons and decreases the Mulliken electrons of Fe 4 s orbital, which weaken the bonding interaction between H and Fe atoms. H atom diffuses into subsurface through a distorted tetrahedron. Surface strain does not change diffusion path but affects the diffusion barrier energy. Tetrahedron gap volume in the transition state of compressive system decreases to increase the diffusion barrier. This suggests compressive strain impedes H penetrating into the Fe subsurface. The present results indicate that it is a way to control adsorption and diffusion of hydrogen on the Fe surface by surface strain.     

单轴应变对H在α-Fe中占位及扩散的影响

采用基于密度泛函理论的第一性原理方法,研究了H在不同单轴应变下α-Fe中的间隙占位,计算了H原子的溶解能、态密度、电荷差分密度和电荷布居.结果表明:不同单轴拉压应变作用下,H原子优先占据四面体间隙(Ts)位,且随着压应变减小、拉应变增加,H原子越易溶于α-Fe.压应变使得Ts位的H获得更多的电子,而拉应变减少了这种电荷转移.应用LST/QST过渡态搜索计算垂直应变方向的扩散.八面体间隙位是邻近Ts位H的扩散过渡态.扩散激活能与应变呈线性关系,且随着压应变的增加,扩散激活能降低,扩散更容易.     

高反压硅功率晶体管的设计和试制

近几年来,国内外对于高反压硅功率管进行了较多的研究工作.这次我们半导体专业1970级工农兵学员利用毕业实践的机会,组成了试制小组,在校办《九一二》电子厂半导体车间的工人同志帮助和专业教师的指导下,初步试制出高反压硅功率管.本文就是我们小组的小结. 一、简 介 高反压硅劝率晶体管主要应用于彩色电视机的垂直偏转和水平偏转的电路中,以及雷达显示电路和其它耐高压的场合,其工作电压一般为数百伏,电流为数安培,频率fT在 1MC左右,β在 5-10倍以上. 我们试制的高反压管为硅NPN型,其参数要求如下: Pcm=50W;Icm=3A;BVcbo≥1.2kV;光刻…