五地视频连线音频系统实践与探讨

按照四川省委、省政府统一安排部署,2021年3月29日,四川眉山举办了四川省2021年第一季度重大项目集中开工会议.此次会议视频连线由四川广播电视台高清转播车坐阵眉山主会场,分别与4个分会场(成都、遂宁、宜宾及资阳)进行实时音视频连线.以重大项目集中开工会议视频连线为背景,详细介绍此次视频连线音频系统的制作实践,阐...     

数字字符识别算法研究

字符识别是模式识别领域内多数课题均会遇到的基本问题。数字字符识别技术是图像处理领域中的一个重要研究方向,且在各领域的应用越来越广泛。本文描述了一种改进后的数字字符识别处理方案。首先对输入的数字字符图像进行预处理,并且对二值化后的图像进行梯度锐化和形态学处理以去除图像中背景的噪声,从数字中选出局部特征,利用结构语句识别的方法进行数字的识别.这个方法提高了识别数字的准确度和速度,并通过实验证明了其可行性。     

基于等离子体相位特性的谐波抑制方法

本文对等离子体的相位特性进行分析并给出详细的公式推导过程。基于此,提出了一种波导滤波器谐波抑制新方法并进行了新型等离子体滤波器的设计。仿真结果表明,此等离子体滤波器的三次谐波能够抑制在-20dB以下,其峰值相比传统滤波器结构的结果降低了18.5dB,起到了显著的抑制效果,充分证实了方法的有效性。     

毫米波光栅谱仪分辨率的研究

对具有一定入射角的波束经球面镜聚焦后焦点区域场的分布进行理论计算与实验测试,结果表明:在毫米波光栅谱仪(25～100GHz)中大球面镜聚焦系统明显限制了频谱分辨率.增大光栅对波束的衍射角是减小和消除这一限制的有效方法.     

Efficient light scattering modeling for alignment, metrology, andresist exposure in photolithography

In previous work, a two-dimensional waveguide model has been developed and examined extensively so that rigorous light scattering calculations for photolithography-related processes, such as stepper alignment, linewidth and overlay measurements, and resist bleaching, can be performed. The computation, however, is expensive if the wafer topography involved is complicated or if resist bleaching problems are involved. Numerical techniques that reduce CPU usage by approximately an order of magnitude are reported. These techniques make the waveguide model more practical to use. Typically, for each polarization state, it takes 10 to 200 s to simulate a static case (e.g. linewidth measurement), and it is projected that it will take 7 to 70 min to simulate a dynamic case (e.g. resist bleaching under 13 incoherent illumination point sources and ten exposure steps) on a high-speed workstation such as an IBM RISC/6000 Model 530     

纳米电子技术

微电子技术引发了本世纪的信息革命。纳米科学技术将成为二十一世纪信息时代的核心和国际科学界和工程技术界关注的热点。     

信息网络战新趋势研究

随着信息和网络技术的飞速发展,信息网络战的发展趋势及作战形式成为军事界热门话题.新时期的信息网络战已经成为一种优先被考虑的,贯穿战争整个过程的,破坏性极大的“顶级”作战形式,它的成败将直接关系到国家的安危与存亡.文章通过对最近几年信息网络战经典案例研究,总结分析了其所呈现出的新趋势,并为军队适应信息网络战的发展变化提出了几点建议.     

基于多变量动态算法的Hadoop负载均衡优化与实现

分析了云计算平台Hadoop负载均衡机制,针对Hadoop系统自带的均衡器要预先输入阈值才能运行的不足,通过多变量动态估计阈值对其进行优化与实现,依据集群磁盘空间负载情况和集群繁忙程度,动态估计均衡器的阈值,并给出了与估计阈值相关的计算公式,在此基础上采用集群系统对上述算法进行了测试验证.实验结果表明,对比Hadoop系统自带的需要固定阈值的均衡器,新方法能在均衡过程中利用系统相关信息动态估计阈值,对Hadoop的负载均衡优化取得更加令人满意的效果.     

Facilitation of Gene Transfection and Cell Adhesion by Gelatin‐Functionalized PCL Film Surfaces

Efficient local gene transfection on a tissue scaffold is of crucial importance in facilitating tissue repair and regeneration. In this work, the gelatin‐functionalized polycaprolactone (PCL) film surfaces are prepared via surface‐initiated atom transfer radical polymerization of glycidyl methacrylate. The resultant covalent attachment of gelatin could enhance the cell‐adhesion and local gene transfection properties. The gelatin‐functionalized PCL film surfaces exhibit excellent cell‐adhesion ability to both adherent and suspension cells. The attached adherent cells demonstrate the characteristic elongated morphologies with good spreading capability, while the attached suspension cells can maintain the original status of the round morphologies without spreading. More importantly, the gelatin coupled on the PCL surface could be used to absorb the cationic vector/plasmid deoxyribonucleic acid (pDNA) complexes via electrostatic interaction. The local gene transfection property on the immobilized cells is dependent on both the density of the immobilized cells and the loading types of pDNA complexes. The transfection efficiency of different assemble methods of pDNA complex was compared. With the pre‐ and post‐loading sandwich‐like gene transfection, the gelatin‐functionalized PCL film surface can substantially enhance the transfection properties to different cell lines. The present study is very useful to spatially control local gene delivery within PCL‐based tissue scaffolds.     

Application of maximum elevation angle probability density function to macroscopic selection diversity in low earth orbiting satellite constellation systems

In a low earth orbiting satellite constellation of communication satellites, the so‐called macroscopic selection‐diversity (SD) scheme selects the satellite with the maximum elevation angle among the visible satellites as being capable of providing the best quality link for signal propagation. To evaluate the performance of this scheme, we developed a model based on macroscopic SD to describe the probability density function of the maximum elevation angles from an earth station to each visible satellite. The model has the advantage of not involving orbital simulations for data collection, thus avoiding statistical processing as well as curve fitting. We evaluated the model by using it to simulate the bit‐error‐rate performance of binary‐phase‐shift‐keying modulation in the Globalstart‐like Walker 48/8/1 satellite constellation. Copyright © 2012 John Wiley & Sons, Ltd.