Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450...Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450℃induces significant temperature gradients,resulting in a proliferation of defects.The scarcity of comprehensive research on this crystal’s defects hinders the enhancement of crystal quality.In this study,we employed the chemical etching method to examine the etching effects on Lu_(2)O_(3)crystals under various conditions and to identify the optimal conditions for investi⁃gating the dislocation defects of Lu_(2)O_(3)crystals(mass fraction 70%H3PO4,160℃,15-18 min).The morphologies of dislocation etch pits on the(111)-and(110)-oriented Lu_(2)O_(3)wafers were characterized using microscopy,scanning electron microscopy and atomic force microscopy.This research addresses the gap in understanding Lu_(2)O_(3)line defects and offers guidance for optimizing the crystal growth process and improving crystal quality.展开更多
该文对基于非实时信道状态信息(Channel State Information,CSI)的多用户放大转发(Amplify-and-Forward,AF)协作通信系统的性能进行分析。系统采用一点对多点的通信系统模型,中继节点根据过时的CSI选择用户。通过推导得出中断概率、信...该文对基于非实时信道状态信息(Channel State Information,CSI)的多用户放大转发(Amplify-and-Forward,AF)协作通信系统的性能进行分析。系统采用一点对多点的通信系统模型,中继节点根据过时的CSI选择用户。通过推导得出中断概率、信道容量和符号错误概率(Symbol Error Rate,SER)的近似表达式。理论分析适用于链路同分布或者非同分布。仿真结果验证理论的正确性,并说明了各种参数对系统性能的影响。同时指出,增加用户数并不能提高系统性能,性能的提高可以通过改变中继的位置来实现。展开更多
在有线数字电视广播(Digital video broadcast,DVB-C)中针对数字视频监管和版权保护问题,提出一种基于数字水印和TI DaVinci技术的信息安全监测系统。通过视频服务器将数字水印嵌入到电视节目视频中,嵌入水印的视频以传输流(Transport s...在有线数字电视广播(Digital video broadcast,DVB-C)中针对数字视频监管和版权保护问题,提出一种基于数字水印和TI DaVinci技术的信息安全监测系统。通过视频服务器将数字水印嵌入到电视节目视频中,嵌入水印的视频以传输流(Transport stream,TS)的形式从视频服务器经同轴线传送到数字机顶盒,然后机顶盒经条件接收和解码后播放电视节目并从中提取数字水印。实验结果表明安全检测系统嵌入水印时不影响原始视频的视觉效果,并且能够准确有效地提取数字水印。数字水印对编解码、视频丢帧和视频拷贝等攻击具有较好的鲁棒性,达到视频跟踪和版权认证的要求。展开更多
基金Supported by National Key Research and Development Program of China(2021YFB3601403)National Natural Science Foundation of China(62105181)Taishan Scholar of Shandong Province(tsqn202306014)。
文摘Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450℃induces significant temperature gradients,resulting in a proliferation of defects.The scarcity of comprehensive research on this crystal’s defects hinders the enhancement of crystal quality.In this study,we employed the chemical etching method to examine the etching effects on Lu_(2)O_(3)crystals under various conditions and to identify the optimal conditions for investi⁃gating the dislocation defects of Lu_(2)O_(3)crystals(mass fraction 70%H3PO4,160℃,15-18 min).The morphologies of dislocation etch pits on the(111)-and(110)-oriented Lu_(2)O_(3)wafers were characterized using microscopy,scanning electron microscopy and atomic force microscopy.This research addresses the gap in understanding Lu_(2)O_(3)line defects and offers guidance for optimizing the crystal growth process and improving crystal quality.
基金Supported by the State Key Laboratory of Sensor Technology Fund(SKT1202)China Postdoctoral Science Foundation(2012M521319)thecrosswise project "Application of micro NIR spectrograph in the wireless sensornetwork"(2015-1-1273)
文摘该文对基于非实时信道状态信息(Channel State Information,CSI)的多用户放大转发(Amplify-and-Forward,AF)协作通信系统的性能进行分析。系统采用一点对多点的通信系统模型,中继节点根据过时的CSI选择用户。通过推导得出中断概率、信道容量和符号错误概率(Symbol Error Rate,SER)的近似表达式。理论分析适用于链路同分布或者非同分布。仿真结果验证理论的正确性,并说明了各种参数对系统性能的影响。同时指出,增加用户数并不能提高系统性能,性能的提高可以通过改变中继的位置来实现。
文摘在有线数字电视广播(Digital video broadcast,DVB-C)中针对数字视频监管和版权保护问题,提出一种基于数字水印和TI DaVinci技术的信息安全监测系统。通过视频服务器将数字水印嵌入到电视节目视频中,嵌入水印的视频以传输流(Transport stream,TS)的形式从视频服务器经同轴线传送到数字机顶盒,然后机顶盒经条件接收和解码后播放电视节目并从中提取数字水印。实验结果表明安全检测系统嵌入水印时不影响原始视频的视觉效果,并且能够准确有效地提取数字水印。数字水印对编解码、视频丢帧和视频拷贝等攻击具有较好的鲁棒性,达到视频跟踪和版权认证的要求。
