A simplified dispersion limit formula for IM/DD systems and itscomparison with experimental results

A simplified formula for the dispersion limit of single-mode-fiber intensity modulation/direct detection (IM/DD) systems is derived for arbitrary given normalized pulse width U, eye opening penalty X and source linewidth enhancement factor α. From the comparison with published theoretical analyses, computer simulation and experimental data, its validity and the limits of existing formulae are shown. Using this simple and general formula, one can easily obtain the dispersion limit of various fiber types under different working conditions in IM/DD systems     

Analysis of an arbitrarily inclined slot on the ground plane of amicrostrip line

The analysis of an arbitrarily inclined slot on the ground plane of a microstrip line is presented using the spectral domain approach and reciprocity theorem. Comparison of numerical results for the special case of a perpendicular slot with other available computed and measured data shows a good agreement. It is found that the impedance level can be controlled over a wide range by varying inclination angle. Results should be useful in antenna and multilayer circuit integration applications     

N-Methyl-D-aspartate attenuates opioid receptor-mediated G protein activation and this process involves protein kinase C

The effects of N-methyl-D-aspartate (NMDA) on opioid receptor-mediated G protein activation were explored in neuroblastoma X glioma hybrid (NG108-15) cells. Treatment of the cells with NMDA resulted in a remarkable attenuation of [35S]guanosine-5'-O-(3-thio)triphosphate binding stimulated by [D-Pen2,D-Pen5]-enkephalin (DPDPE), a delta-opioid receptor agonist. The effects of NMDA were dose and time dependent with an IC50 value of 5 nM and could be blocked by NMDA receptor antagonists. After NMDA treatment, the DPDPE dose-response curve shifted to the right (EC50 value increased approximately 7-fold, from 6 to 40 nM), and the maximal response induced by DPDPE was reduced by approximately 60%. The effects of NMDA were reversible, and the DPDPE response could recover within 60 min. The functional responses of delta-, mu-, and kappa-opioid receptors in primarily cultured neurons also were attenuated significantly by NMDA treatment. The inhibitory effects of NMDA on opioid receptor-mediated G protein activation could be blocked by coadministration of the protein kinase C (PKC) inhibitors or by elimination of the extracellular Ca2+. Correspondingly, NMDA treatment of NG108 cells significantly elevated cellular PKC activity and stimulated Gialpha2 phosphorylation. Transient transfection into NG108-15 cells of the wild-type Gialpha2 and a mutated Gialpha2 (Ser144Ala) resulted in a 2-fold increase in DPDPE-stimulated G protein activation. The DPDPE responses were greatly inhibited by NMDA treatment in the wild-type Gialpha2-transfected cells but much less affected in the mutant Gialpha2-transfected cells. In summary, NMDA attenuates opioid receptor/G protein coupling, and this process requires activation of PKC.     

专用设备驱动程序交互式生成器的设计与实现

主要作为电子高科技的重点领域，专用实时设备无论类别和型号，抑或数量和质量，均与日俱增，令人目不暇接。它们的高效管理与灵活加接，是任何计算机专用实时系统不可或缺的基本功能，其驱动模块随之成为任何专用实时系统无法回避的设计难点。本文介绍我们自行研制的专用实时设备驱动程序交互式生成器ＲＴＤＧ的设计与实现。     

基于超高频雷达的湖面风浪参数提取

基于Barrick的微绕散射理论,在超高频雷达USCR工作频率条件下,将反演均方高浪高公式应用于超高频雷达USCR提取湖面风浪信息,在国内首次实现从湖面回波多普勒谱中获取了浪高信息;并利用Heron理论,由浪高信息反演出风速风向信息;通过模拟相同风浪状态下的湖面回波,并进行对比证明本方法是行之有效的。     

基于特征线匹配的城市建筑物识别方法研究

随着手机GPS位置测定、导航以及摄像功能的普及,对于移动状态下的位置定位以及都市空间建筑物实时搜索等应用功能存在日益增长的需求。介绍了图像处理方式的城市建筑物识别方法,通过对两种图像匹配算法--SIFT和Local Search的比较分析表明,构造物轮廓线及其组合是一种相对稳定的几何特征,在匹配时受图像的仿射变换、画质变化以及镜头畸变等因素干扰较小,此外,基于轮廓的图像匹配指数还能反映摄影位置的变化。因此,对Local Search进行了改进,利用实时图的建筑物的特征轮廓线与从三维数据库中提取的建筑群特征轮廓线进行匹配,然后选择匹配指数高的记录作为识别结果。结果表明基于Local Search算法的建筑物识别技术可以很好地适应移动条件下建筑物快速识别的要求。     

优酷＋土豆=？

2012年3月12日,前段时间还就版权问题大打口水仗的优酷和土豆突然宣布合并,业内一片哗然。两个竞争对手因何结成了亲家？这场联姻又将带来什么？     

从光合作用的倒掉说起

席殊书屋、第三级书局走了,风入松、纸老虎世纪城店关了,我没太在意。2010年10月底,有着36家连锁店的光合作用竟然也宣告倒闭了!我终于淡定不起来了。清华大学出版社零售产品经理王川（简称川）清华大学出版社图书编辑刘青（简称刘）记者Justdo（简称J）新华书店＋网购是必然趋势J：光合作用倒闭了,你们惊讶吗？刘：其实我挺惊讶,因为我常去,特别是五道口那家店,从刚开业起就经常去逛。     

Win8会是微软的又一力作吗

在2012MWC世界移动通讯大会上,微软正式发布了Windows8消萤者预览版,引起了广泛的热议。Windows8会像微软的历次操作系统一样,获得巨大的成功吗？     

基带芯片 智能手机不能没有你

我们在买手机时总是重点关注它的CPU和GPU,但又有多少人晓得基带芯片的重要性?前不久曾传出德州仪器(TI)有意退出智能移动终端处理器市场的消息。虽然随后TI又表示OMAP5系列处理器还是会如期面世,但无论如何,德州仪器确实面临着市场份额减少、需求萎缩的问题,而这与其缺乏完整的解决方案有着密切的关联。其中最核心的问题是TI缺乏3G/4G网络基带芯片,因此越来越多的智能移动终端厂商更为青睐有着完整解决方案的高通公司。那么,基带芯片的影响真有那么大吗?