Hierarchical Magnetic Network Constructed by CoFe Nanoparticles Suspended Within “Tubes on Rods” Matrix Toward Enhanced Microwave Absorption

Hierarchical magnetic-dielectric composites are promising functional materials with prospective applications in microwave absorption(MA)field.Herein,a three-dimension hierarchical“nanotubes on microrods,”core–shell magnetic metal–carbon composite is rationally constructed for the first time via a fast metal–organic frameworksbased ligand exchange strategy followed by a carbonization treatment with melamine.Abundant magnetic CoFe nanoparticles are embedded within one-dimensional graphitized carbon/carbon nanotubes supported on micro-scale Mo2N rod(Mo2N@CoFe@C/CNT),constructing a special multi-dimension hierarchical MA material.Ligand exchange reaction is found to determine the formation of hierarchical magnetic-dielectric composite,which is assembled by dielectric Mo2N as core and spatially dispersed CoFe nanoparticles within C/CNTs as shell.Mo2N@CoFe@C/CNT composites exhibit superior MA performance with maximum reflection loss of−53.5 dB at 2 mm thickness and show a broad effective absorption bandwidth of 5.0 GHz.The Mo2N@CoFe@C/CNT composites hold the following advantages:(1)hierarchical core–shell structure offers plentiful of heterojunction interfaces and triggers interfacial polarization,(2)unique electronic migration/hop paths in the graphitized C/CNTs and Mo2N rod facilitate conductive loss,(3)highly dispersed magnetic CoFe nanoparticles within“tubes on rods”matrix build multi-scale magnetic coupling network and reinforce magnetic response capability,confirmed by the off-axis electron holography.     

基于无线数据业务智能优化系统算法的研究与应用

针对业界GPRS/EDGE无线数据优化方法、算法不完善,工作效率低的问题,广西联通通过长期研究建立了一套优化经验方法和较适合现网的参数配置、算法,并将这套方法、算法应用到自主开发的无线数据业务智能优化系统中,使系统实现自动采集分析数据、自动提供优化方案、自动执行优化方案、自动生成优化报告功能,使无线数据业务优化工作朝着智能化方向迈进。     

类金刚石薄膜的Raman光谱分析及红外光谱特性

用酒精和氢气的混合气体为工作气体 ,在不同的酒精浓度下 (1 0 % ,1 5% ,2 0 % )下利用微波等离子体化学气相沉积法在较低温度下 (450～ 50 0℃ )以单晶硅为衬底制备出类金刚石薄膜样品。 Raman光谱分析了酒精浓度对薄膜中金刚石成份的含量的影响。红外光谱分析表明薄膜的红外光透过率与薄膜的表面形貌、薄膜结构有关。酒精浓度为 1 0 %时得到的金刚石薄膜的红外光透过率最高 ,达到 62～ 72 % ,同时透过率曲线因薄膜干涉而引起的振荡也最为显著。     

高增益真对数放大器技术在雷达中的应用

从分析真对数放大器(TLA)基本原理入手讨论了高增益真对数放大器的性能特点;通过高增益真对数放大器传输函数的数学公式推导,介绍一种新型真对数放大器(TLA)的设计方法;最后给出了一个在雷达接收机中的应用实例.     

The Main Progress of Perovskite Solar Cells in 2020–2021

Perovskite solar cells (PSCs) emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from ...     

Nanoparticle–Cartilage Interaction: Pathology?Based Intra?articular Drug Delivery for Osteoarthritis Therapy

Osteoarthritis is the most prevalent chronic and debilitating joint disease, resulting in huge medical and socioeconomic burdens. Intra-articular administration...     

Development of CNPC’s Drilling Business

With further exploration and development of oil and gas fields both at home and abroad,complicated geological conditions,poor quality of reserves and abominable working environment,drilling business,the largest of upstream petroleum     

Excel计划表在上海环球金融中心进度管理中的应用

上海环球金融中心大厦采用Excel网格图、图表进行进度计划的编制.经过精心编制,合理利用,有效协调了众多分包商的工程界面搭接、穿插施工和多家参与单位的合作.介绍了施工总流程和总进度进化的编制,以及季度计划、月计划和周计划的编制方法及注意事项.总结出Excel办公软件进行进度计划编制的特点及优点.     

基于LC谐振电路的智能配送无人机设计

针对传统配送机器人在配送过程中出现的路径偏差,与顾客发生碰撞等问题,设计了一种基于电磁循迹的配送无人机.使用四轴飞行器作为主体,利用LC谐振电路作为传感器检测电磁信号,进行路径跟踪,避免了周围环境对配送无人机循迹过程的影响.无人机采用基于四元数的姿态解算算法进行姿态解算,并通过改进的串级模糊PID控制算法控制无人机的飞行速度和方向,提高了配送无人机的响应速度和稳定性,无人机能够更好的完成配送任务,具有应用和推广价值.