MEMS器件捷联惯导系统旋转调制技术

使用微机电(MEMS)惯性器件利于捷联惯导系统的低成本和小型化,但MEMS器件误差较大.为提高系统精度,引入了一种全自主误差补偿方法——旋转调制.说明了旋转调制对常值误差的抑制作用和对导航精度的改善效果,并在旋转轴数目、旋转方向、旋转连续性和旋转速度等方面比较了不同旋转调制方案.根据MEMS器件的误差特性,选择了一种适合MEMS器件捷联惯导系统的旋转调制方案并自主研发了原理样机.静态和车载实验表明:旋转调制可以明显抑制MEMS器件常值误差对导航精度的影响,200s内俯仰和横滚姿态精度提高了5倍,速度和位置精度提高了近10倍.     

Research progress in ZnO single-crystal: growth,scientific understanding,and device applications

Zinc oxide, a wide band-gap semiconductor, has shown extensive potential applications in high-efficiency semiconductor photoelectronic devices, semiconductor photocatalysis, and diluted magnetic semiconductors. Due to the undisputed lattice integrity, ZnO single crystals are essential for the fabrication of high-quality ZnO-based photoelectronic devices, and also believed to be ideal research subjects for understanding the underlying mechanisms of semiconductor photocatalysis and diluted magnetic semiconductors. This review, which is organized in two main parts, introduces the recent progress in growth, basic characterization, and device development of ZnO single crystals, and some related works in our group. The first part begins from the growth of ZnO single crystal, and summarizes the fundamental and applied investigations based on ZnO single crystals. These works are composed of the fabrication of homoepitaxial ZnO-based photoelectronic devices, the research on the photocatalysis mechanism, and dilute magnetic mechanism. The second part describes the fabrication of highly thermostable n-type ZnO with high mobility and high electron concentration through intentional doping. More importantly, in this part, a conceptual approach for fabricating highly thermostable p-type ZnO materials with high mobility through an integrated three-step treatment is proposed on the basis of the preliminary research.     

Novel laminated multiferroic heterostructures for reconfigurable microwave devices

Voltage tuning of magnetism is fundamentally and technically important for fast, compact and ultra-low power electronic devices. Multiferroic heterostructures,simultaneously exhibiting distinct ferroelectric and ferromagnetic properties, have caught a lot of attentions because of the capability of controlling magnetism by a voltage via a strain-mediated magnetoelectric（ME） coupling. In these materials, a voltage-induced strain is involved to create an effective magnetic field and change ferromagnetic resonance frequency in the coupled ferromagnetic phases through magnetoelastic interactions. Therefore, the devices made of such materials are compact, ultra-fast and energy efficient,providing new functionalities for microwave components.This paper will review the recent progress of multiferroics and their applications in microwave devices from different aspects, including the creation of the novel laminated multiferroic heterostructures with a strong ME coupling, the realization of the multiferroics based on tunable microwave signal processors and the investigation of nonvolatile tuning of microwave properties using ferroelastic domain switching in multiferroic heterostructures. These tunable multiferroic heterostructures and devices offer great opportunities for realizing the next generation of tunable magnetic microwave components, ultra-low power electronics and spintronics.     

某型飞机一起机身异常振动故障分析

<正>1故障基本情况某部本场组织某型飞机进行起落航线训练,第一轮训练结束飞机着陆后,飞行员解除限动,同时脚踩刹车减速时感觉飞机异常振动明显。当飞行员停止刹车时,飞机又平稳滑行。在飞机转向滑行道时,先刹车减速,同时使用前轮转弯操作手柄操纵前轮转弯困难。2故障机理分析产生飞机异常震动的原因主要为:(1)机轮LS-108A轴承调节衬套调整不当,或轮毂、轴承及调节衬套不配套,使主轮轴向间隙过大产生震动。(2)调节衬套与轴承安装的螺帽松动。(3)机轮轴承严重磨损产生间隙。(4)刹车系统故障。     

基于闭环加速度检测系统的MEMS加速度传感器模型

本文针对体硅梳齿结构的电容式加速度传感器进行建模,考虑到了极板间静电力影响,对闭环反馈式加速度检测系统的设计及调节提供了可能及便利;基于VerilogA对该模型进行描述,使其能够和主流的IC电路设计工具进行兼容,对于系统功能搭建及性能的调节具有直接性,便利性。根据仿真结果表明,该模型如实反映了MEMS电容式加速度计的工作状态,尤其对闭环加速度计检测系统的设计提供有效的帮助。     

物理光学中黑白光栅衍射特征的计算机仿真

1 引言 近几十年来,现代光学最重要的进展之一就是光学信息处理和数字计算的飞速发展。光栅作为传统的光学器件,在众多领域里发挥着重要的作用。随着光产业的不断发展,人们对光栅这样一种重要的光学器件提出了更多也更加苛刻的要求。通常,在光栅衍射实验中,其实验条件是非常苛刻的,这将影响我们准确地分析和研究其实验结果。     

光子晶体耦合腔波导中的慢光特性研究

研究了二维光子晶体耦合腔波导的慢光传输特性.利用平面波展开法分析不同结构的耦合腔波导的色散曲线.分析发现,光子晶体耦合腔波导的慢光特性与点缺陷微腔的几何尺寸有关.通过调制点缺陷的半径可以改变慢光导模的中心频率.另外发现,点缺陷微腔间距也是影响耦合腔波导慢光特性的重要参数.增大距离n,零色散点导模的群速度明显下降,可以获得群速度为0.005c的慢光模式,而导模的中心频率变化不大.该分析结果为设计不同要求的慢光波导结构提供重要参考.     

基于LWSFLA-SVM的人脸识别算法*

目的用线性调整惯性权重的蛙跳算法(linear decreasing inertia weight shuffled frog leaping algorithm,LWSFLA)训练支持向量机(support vectors machines,SVM),解决人脸识别中SVM在训练样本数较多且维数较高时,识别效果不理想的缺陷。方法该算法先用反向学习法产生初始群体提高初始解的质量,再修改最差青蛙的更新策略,并引入线性递减的惯性权重,最后应用于人脸识别中。结果与结论 ORL和CAS-PEAL-R1人脸库的仿真实验表明,LWSFLA-SVM方法的人脸识别时间短,识别率高,在训练样本不足时,识别效果良好。     

基于FPGA与DSP的DS12CR887精密时钟设计

DS8887是一款内置晶振和锂电池的高精度时钟芯片.介绍一种基于FPGA和DSP使用DS887精密时钟芯片的设计方案.采用FPGA可以缩小设计周期,便于硬件实现,提高系统的稳定性;通过DSP控制实现对时间的读取与写入.本设计使得时钟的读取运行时间短,操作简单,系统稳定.     

全薄膜电致变色器件glass/ITO/NiO_x/ZrO_2∶H/WO_3/ITO中单层膜的表征及器件的光学性能

采用磁控溅射法制备了glass/ITO/NiOx/ZrO2:H/WO3/ITO全薄膜电致变色器件,并对单层膜的结构及性能进行了研究.器件中NiOx、ZrO2:H和WO3各单层薄膜的SEM、XRD以及XPS的测试结果表明:NiOx薄膜表面颗粒之间有孔隙存在,这些空隙有利于H+的嵌入和脱出;而ZrO2:H薄膜和WO3薄膜的表面粗糙,颗粒度较小,这样的表面形貌有利于电致变色反应的发生.采用紫外-可见光分光光度计对器件的光学性能及循环寿命进行研究,器件经历60000次连续着褪色循环后,着色响应时间明显迟缓,褪色响应时间变化不显著,在可见光范围内的透过率调节范围仍可以达到57.9%,表明该器件具有良好的可见光调制性能和较长的循环寿命,初步达到了商业化应用的要求.