Results 21 to 30 of about 5,382 (129)

基于高光谱的夏玉米冠层SPAD值监测研究

open access: yesShuitu Baochi Xuebao, 2019
开展夏玉米冠层SPAD值监测技术研究,建立叶绿素含量与敏感波段、光谱指数间的定量关系模型,以促进高光谱技术在玉米快速、无损长势监测及水肥精准管理的应用。以小型蒸渗仪夏玉米光谱反射率与植株冠层SPAD值的监测为基础,研究了夏玉米植株冠层光谱信息与SPAD值的响应关系,并优选出监测夏玉米冠层SPAD值的敏感波段与最优光谱指数。结果表明:夏玉米冠层光谱反射率在可见光波段随玉米冠层SPAD值增加而下降,在近红外波段却与之相反;采用原始光谱反射率、一阶微分光谱监测夏玉米冠层SPAD值的最敏感波段分别为700 ...
刘露   +5 more
doaj  

湿热环境硅橡胶含水率的激光诱导击穿光谱检测

open access: yesGaoya dianqi, 2022
湿热环境中,硅橡胶含水率过高会导致复合绝缘子老化加剧及温度升高等问题,目前缺乏一种能够对运行硅橡胶绝缘子含水率带电检测的手段。文中提出一种基于激光诱导击穿光谱技术的硅橡胶含水率检测方法,研究了延迟时间、激光能量等参数对于光谱质量的影响,并且比较了不同特征谱线强度与含水率的定标结果。结果表明,延迟时间为3μs时光谱质量最优,此时连续背景谱几乎衰减消失并且线性谱仍保持一定强度;激光能量较高时,水分在高温下蒸发对等离子体形态的影响程度提高,进而削弱特征谱线强度随含水率的变化趋势,激光能量为35.4、44.7 ...
周卓伟   +4 more
doaj  

Synergistic Dual‐Defect Engineering in Amorphous‐Nanocrystalline Heterostructures for Accelerated Oxygen Evolution

open access: yesRare Metals, Volume 45, Issue 7, July 2026.
ABSTRACT Defect engineering has been widely demonstrated as an effective strategy for enhancing the activity of OER metal catalysts, among which the introduction of twin boundaries (TBs) has proven particularly efficient. However, single‐type defects offer limited performance enhancement.
Wentao Cai   +11 more
wiley   +1 more source

基于光子晶体光纤高质量超连续谱的优化设计

open access: yesGuangtongxin yanjiu, 2011
采用分布傅里叶方法模拟了光子晶体光纤超连续谱的产生,分析了超连续谱的产生机理与不同光子晶体光纤超连续谱的特点,分析结果表明,在正常色散区可以获得高质量超连续谱。优化光子晶体光纤结构,利用脉宽为100fs、峰值功率为500W的高斯脉冲通过10m长的优化光子晶体光纤,在1 550nm波段获得了宽度为210nm、平坦度为3dB的超连续谱。
朱瑞莲, 闫连山, 李立广
doaj  

La3+ Vacancy Mediated Enhancement of Near‐Infrared Emission in Cr3+‐Activated La2MgTiO6 Phosphors for Multifunctional Applications

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT Near‐infrared (NIR) phosphors with broadband and efficient emission are pivotal for the performance of NIR phosphor‐converted light emitting diodes (pc‐LEDs). In this study, the double perovskite phosphor La2MgTiO6:Cr3+ phosphor with broadband emission in the range of 650–950 nm was prepared.
Xu Qian   +7 more
wiley   +1 more source

Atomically Thin Sn:GaN‐GaN Homojunction for High‐Sensitivity β‐Ray Detection

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT Gallium nitride (GaN), a third‐generation wide‐bandgap semiconductor renowned for its superior radiation tolerance, holds promise for advanced β‐ray detection. Herein, a scalable liquid metal‐assisted in situ synthesis method is presented to fabricate Sn‐doped GaN homojunctions via gallium oxide printing followed by ammonolysis, enabling ...
Weiqing Liu   +8 more
wiley   +1 more source

Nd∶YAG晶体中色心的发光特性和激光超辐射实验

open access: yes四川大学学报. 自然科学版, 1997
研究了电阻炉生长的Nd∶YAG晶体中色心的吸收光谱、激发光谱和发射光谱以及热处理和辐照对光谱特性的影响.分析了色心形成的机理.用含色心的Nd∶YAG棒做激光实验,观察到超辐射输出.
张邦星, 王化莹
doaj  

Oxygen Doping and Crystal–Amorphous Multiphase Coupling Synergistically Improve the Wear Resistance of NiTiCu Alloy

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT NiTi shape memory alloys (SMAs) show excellent performance in vibration damping and corrosion resistance. However, due to low hardness and lack of self‐lubrication, they suffer severe friction and wear during service. Although various strategies including doping and heterostructure design have been proposed, the effects are unsatisfactory.
Huwen Ma   +13 more
wiley   +1 more source

异质结构材料的傅立叶变换光萤光谱的测试与分析

open access: yesGuangtongxin yanjiu, 1996
介绍了傅立叶交换光萤光谱测试的基本原理;报道了用PL6120设备测得的一些典型的异质结构材料光萤光谱;分析和讨论了光萤光双峰结构、光萤光谱异常温度特性等问题;指出了异质界面上原子排列无序和内应力是造成这些异常现象的物理原因。
丁国庆
doaj  

Enhancement of Corrosion and Wear Resistance in Polymeric Coatings via Ce(III)‐Functionalized Ternary ZnAlCe Layered Double Hydroxides Intercalated With EDTMP

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT The intricate corrosion environment necessitates the polymeric coating's adaptability to the surroundings. In this work, the integration of rare‐earth Ce(III) ions and ethylene diamine tetramethylene phosphonic acid (EDTMP) in a layered double hydroxide (LDH) material is developed to enhance the corrosion protection and anti‐wear properties of
Yangu Liu   +9 more
wiley   +1 more source

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