卫星移动通信系统的比较和发展概况

国际移动通信标准的制订和系统设计曾受到20世纪90年代信息泡沫的严重影响,许多标准和系统存在着不合理现象,在应用中值得重视。文章在比较了多个卫星移动通信系统设计方案和运营状况的基础上,指出在卫星移动通信系统中应重视的几个设计参数,如多址方式的选择、卫星系统的可靠性等。     

基于有限差分强度折减法的多级边坡破坏模式研究

总结了当前多级边坡的稳定性分析方法,引入FLAC^3D程序和强度折减理论,并运用有限差分强度折减法研究了多级边坡随台阶宽度变化的破坏模式、变形及其稳定性。分析结果表明:多级边坡的滑移面的位置、形状和破坏模式随着台阶的宽度不同而不同,且其变形也随着台阶的宽度不同表现出不同的特性。最终通过对多级边坡进行稳定性分析,发现安全系数和滑移面广义剪应变大小也随台阶宽度的变化也表现出一定的规律性。     

紧凑拉伸试件应力强度因子的解析-变分解法以及有关系统计算结果

本文推导了在材料断裂性能测试中常见的受钉传载荷含边缘裂纹试件应力与位移的函数项级数表达式。该级数逐项满足弹性力学所有基本方程、裂纹表面边界条件与绕钉孔的合力平衡条件以及位移单值条件。通过以最小势能原理为基础的变分方程满足其余的静力边界条件,从而求解级数中的待定系数并确定应力强度因子。计算结果表明,级数收敛迅速、正确,计算节省机时,简化数据准备工作。本文还通过计算指出了目前通用的有关矩形紧凑拉伸试件应力强度因子计算公式与曲线的不准确性并且给出了正确、系统的计算曲线,同时还提供了圆形紧凑拉伸试件系统的计算结果。     

基于嵌入式智能家居Cortex-A8服务器的设计

本论文针对智能家居具有高度异构性和动态性的环境、特定的用户人群,着重进行基于嵌入式的智能家居服务器的设计。本文以S5PC100为硬件平台通过软件设计、编程来搭建总控制服务器（Cortex-A8服务器）,其支持普通PC、Pad、LCD、WEB客户端等多种终端登录设备平台来远程控制家居电器设备开启、关闭,摆脱传统采用机械按钮操控家居电器的束缚。     

Direct fabrication of a microfluidic chip for electrophoresis analysis by water-assisted femtosecond laser writing in porous glass

We report the direct fabrication of a microfluidic chip composed of two high-aspect ratio microfluidic channels with lengths of 3.5 cm and 8 mm in a glass substrate by femtosecond laser micromachining. The fabrication mainly consists of two steps: 1) writing microchannels and microchambers in a porous glass by scanning a tightly focused laser beam; 2) high-temperature annealing of the glass sample to collapse all the nanopores in the glass. Migration of derivatized amino acids is observed in the microfluidic channel by applying electric voltage across the long-migration microchannel.     

Microstructuring of anti-reflection film for HgCdTe/Si IRFPA with femtosecond laser pulse

A systematic series of silicon (Si) wafer with microstructured anti-reflection film is prepared by femtosecond laser pulse. The dependence of the morphology and optical properties of the microstructured Si on the experimental parameters is thoroughly investigated. With the laser pulse duration of 40 fs, central wavelength of 800 nm, repetition rate of 250 kHz, laser pulse power of 300 mW, 250 μm/s scanning speed, and 2 μm of displacement between the parallel scans in the air, the quasiordered arrays of grain microstructures on the Si wafer up to 800-nm tall and 800-nm diameter at the bottom offered near-unity transmission in the mid-infrared wavelength. An anti-reflection film of approximately 3 × 3 (mm) is developed on the (211) Si substrate with the optimized parameters, Moreover, up to 30% improvement of the response performance is demonstrated.     

防止光链路本底噪声抬高 确保上行通道信噪比

本文简要分析了FP激光器基本工作原理,叙述了FP激光器衰老后会引起本底噪声抬高的原因,并提出了一些降低上行通道光链路的本底噪声的措施。