Results 21 to 30 of about 27,614 (267)

Study on Corner-Fed Cavity-Backed Slot Dual-Polarized Antennas [PDF]

open access: yes, 2015
为了在2.4GHz频段WLAN中实现具有方向性辐射的MIMO技术,采用背腔环形缝隙结构辐射元,通过倒置正交微带线激励,设计具有一定方向性的正交双极化天线结构。为提高端口间的隔离度和辐射场的极化纯度,在馈线正对的另一侧共面加载尺寸完全一致的接地或不接地导体带条。在此基础上,采用角馈的方法以期进一步改善天线的性能,并对各种可能天线形态进行对比分析。具体内容如下。 (1)对于边馈情形(即馈线位置垂直平分矩形导体腔表面的直角边),可以发现,没有加载导体条时,较佳隔离度对应的频带要高于阻抗工作频带,且相隔距离较大。
谢昇
core  

Prioritized Lithium Extraction From Spent Lithium‐Ion Batteries via Low‐Temperature Chlorination Mediated by Seawater‐Derived Chlorides

open access: yesRare Metals, EarlyView.
ABSTRACT Chlorination roasting has emerged as a promising pyrometallurgical strategy for the selective recovery of lithium from spent lithium‐ion batteries (LIBs). In this study, a natural roasting agent, seawater‐derived chlorides, was employed to selectively extract lithium from spent LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode. MgCl2·6H2O, a main component
Bei‐Lei Zhang   +7 more
wiley   +1 more source

基于扩展Debye模型仿真的回复电压特征量分析

open access: yesGaoya dianqi, 2017
回复电压测量方法(return voltage measurement,RVM)能有效检测变压器固体绝缘的含水量,然而对于含有局部峰值点的回复电压极化谱难以给出明确的诊断结论。文中在扩展Debye模型基础上,仿真分析了模型参数变化对极化谱和主时间常数CTC、回复电压峰值最大值Urmax的影响规律,并提出将扩展Debye模型不同时间常数支路数作为新的特征量,最后验证了该特征量的可行性。仿真和试验结果表明:RVM极化谱前、中、尾3部分分别对应着油纸绝缘变压器油中偶极子转向极化 ...
吴广宁, 宋臻杰, 辛东立
doaj  

Research of Retrieving Sea Surface Wind Vectors Based on Sentinel-1A Satellite SAR Images [PDF]

open access: yes, 2016
海面风场是海气交互界面的重要物理参数,与海洋中绝大多数的海水运动密切相关。海面风场还是海气相互作用的重要媒介,调节了海水和大气之间的物质以及能量输送,对全球气候调节也有着十分重要的作用。 船舶、浮标等观测手段花费高昂,加上海洋面积巨大,可获得的现场海面风场数据十分有限,很难满足大面积海面风场的观测需求。日益发展的卫星遥感技术,为大面积观测风场提供了可能,微波散射计已经成为大面积获取全球海面风场的最重要遥感手段之一,不过微波散射计的空间分辨率通常为25-50km,难以满足对高分辨风场的需求 ...
毕上上
core  

Fabrication‐Driven Oxidation Pathways in Y/Hf‐Modified High‐Entropy Alloys: From Elemental Segregation to Oxide Homogeneity

open access: yesRare Metals, EarlyView.
ABSTRACT This study elucidates the oxidation mechanisms governing Y/Hf‐doped AlCoCrFeNiTi high‐entropy alloys (HEAs) and reveals the pivotal role of fabrication processes in dictating high‐temperature oxidation behavior. We demonstrate that casting and spark plasma sintering (SPS) promote Y/Hf segregation, resulting in heterogeneous oxide formation and
Huaqing Yi   +5 more
wiley   +1 more source

Electro-optic modulation of AlGaN in deep ultraviolet [PDF]

open access: yes, 2016
深紫外非线性光学材料在光信息处理和高速光通讯等领域具有广泛的应用前景,发展适宜工作在深紫外波段的新型非线性光学材料成为国际学术界和产业界研发的热点。AlGaN基半导体凭借宽带隙带来的信道容量大、纤锌矿晶格排列缺乏反演对称性造成的非线性光学效应、以及作为半导体可控制对n型p型的光电集成等优势,成为理想的深紫外波段非线性光学材料,在电光调制和电光开关等非线性光学器件方面极具应用潜力。本文理论设计并生长了高Al组分的AlxGa1-xN/GaN超晶格结构,通过椭圆偏振光谱表征测算AlxGa1-xN ...
吴小璇
core  

Enhanced Low‐Frequency Microwave Absorption and Corrosion Resistance of FeSiAl Using Low‐Melting‐Point Glass Phase Coatings

open access: yesRare Metals, EarlyView.
ABSTRACT This study developed a FeSiAl@LMPGP composite material to address the demand for low‐frequency electromagnetic absorption. Through controllable heat treatment, FeSiAl particles and PbO nanoparticles self‐assembled into a high‐density Mott–Schottky heterointerface structure, which exhibited a significant built‐in electric field (BIEF) effect ...
Yuqi Wang   +5 more
wiley   +1 more source

40.5 kV高海拔穿墙式固封极柱电场分析与结构优化

open access: yesGaoya dianqi, 2020
结构小型化和高绝缘水平的优化设计是固封极柱设计中的重要组成部分。以40.5 kV高海拔穿墙式固封极柱为例,通过对普通结构、外绝缘加高结构、伞裙优化与屏蔽优化相结合等不同结构形式的固封极柱的电场进行分析,实现了绝缘结构的最优化。解决了40.5 kV高海拔穿墙式固封极柱的绝缘问题和局部放电问题,为类似40.5 kV穿墙式固封极柱的绝缘结构优化提供了参考。
李红梅, 王志川, 刘玉春
doaj  

Probing and tunning the light-matter and electron-matter interaction in the quantum regime [PDF]

open access: yes, 2016
对光子和电子与物质相互作用的探知与解读、相互作用行为的驾驭与改造是当今凝聚态物理研究的前沿热点,本论文面向该研究领域,以搭建实验平台为起步,以构建优良材料体系为基础,多方位发掘并呈现体系中的相互作用行为,旨在澄清其背后的物理图像与核心机制,并以此为支点,进一步开展更具目的性的量子行为调控。研究内容与研究意义可简要概括为如下几点: 开发新表征技术:我们首先致力于原位综合表征系统这一实验平台的搭建,并进一步发展了双扫描隧道探针表征技术,以及光纤探针配合下多探针协同的微区光学表征技术 ...
李孔翌
core  

Orbitally Driven Anomalous Thermal Transport Under High Pressure in Gallium Nitride

open access: yesRare Metals, EarlyView.
ABSTRACT Extreme conditions such as high pressure offer opportunities for innovative materials design and applications. For over a century, studies on thermal transport in crystals under high hydrostatic pressure have shown that lattice thermal conductivity generally exhibits a monotonic increase with pressure.
Zong‐Hao Yuan   +8 more
wiley   +1 more source

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