Results 31 to 40 of about 21,249 (196)
Rare Metals, EarlyView.ABSTRACT MCrAlX coatings are widely used as bond coats in thermal barrier coating systems to protect turbine blades from high‐temperature oxidation. However, their oxidation resistance is often restricted by uncontrolled microstructures, surface roughness, and aggregation of reactive elements (REs). In this study, high‐repetition‐rate femtosecond laser
Wei Qian +7 more
wiley +1 more source
Gaoya dianqi, 1999 设计制作了用于研究臭氧合成的小型高频电源,能产生多种频率的高频高压,幅值从0至10kV可调.对沿面放电电极结构初步研究了高频电压下臭氧的合成.
丁卫东 +3 more
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Dianci bileiqi, 2023 为研究温度对环氧胶浸纸绝缘套管频域介电响应特性的影响，开展了环氧胶浸纸绝缘样片在高低温(10℃～120℃)循环下的频域介电谱测试，绘制了不同循环次数下环氧胶浸纸绝缘样片的频域介电响应特性曲线。结果表明：随着高低温循环次数的增加，在120℃时介质损耗因数、复合电容实部和虚部频谱曲线整体向上和高频方向移动，在10℃时在高频区域下介质损耗因数和复合电容虚部的频谱曲线整体向上移动，而复合电容实部的频谱曲线基本保持不变。10℃和120 ...
翟春雨 +6 more
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High Frequency Soft Magnetic Properties of [FeCoSiN/SiNx]n Multilayer Films and Their Applications in Solenoid Microinductor [PDF]
, 2016 随着电子信息技术的飞速发展，多种现代化电子元器件逐渐向集成化、高频化和微型化方向发展。然而，在磁性电子元器件向集成化和高频化发展的过程中还面临着一大困境——缺乏具有优异高频性能（包括低矫顽力、高磁导率、高铁磁共振频率和高电阻率）的软磁薄膜材料。电感器作为一种重要的无源磁性元器件，其性能与体积/面积密切相关。当缩小尺寸（微型化）后势必会导致其性能变差，无法满足器件的使用要求。要突破这一困境，就必须寻找在高频（包括GHz频段）下稳定工作且具有较高磁导率的薄膜材料，并将这种材料作为磁芯集成到微型电感中 ...
刘小龙
core
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Studies have shown that organisms may adjust metabolic rates in response to thermal variability, highlighting metabolic plasticity as a key adaptive mechanism. Understanding the extent of metabolic plasticity of an organism is key to predicting its adaptation to climate
Qian Hu +6 more
wiley +1 more source
Gaoya dianqi, 2005 研制了宽带和窄带两种超高频外置天线传感器,两种传感器增益均大于1,驻波比在其有效带宽范围内均小于2,均能用于GIS局部放电超高频检测。设计了高性能放大器和半分布参数超高频滤波器,工作频带为300～1000MHz,完全覆盖了两种传感器的工作频带。性能测试表明,传感器和滤波放大器性能优良,频率匹配,能满足超高频信号检测预处理的要求。通过对绝缘子表面金属污染缺陷产生的局部放电信号进行检测研究表明,超高频检测系统能够检测到超高频段微弱的局部放电信号,并能抑制低频段干扰,为后续模式识别的研究打下了基础。
唐炬 +4 more
doaj
Word-formation of “Heart” And Teaching Chinese As A Foreign Language [PDF]
, 2015 随着对外汉语的逐渐升温和在世界范围内的迅猛发展，对外汉语的研究视角也随之细化和深化。词汇作为对外汉语中的重要组成部分，既是学生进行语言学习和跨文化交际的要求，也是教师语言要素教学的主体。词汇中，单音节语素在古汉语时期多单独成词使用，随着汉语双音化的发展趋势和语言的经济性原则，这些单音节词逐渐作为重要的成分参与构词，构成的合成词词义也呈现出多样化的态势。从当前的研究来看，对语素义和词义的探索多为列举和表面分析，对义项的内部联系也多通过隐喻、转喻等引申手段加以说明，将之与文化相关联的研究也在逐步展开 ...
杨志娟
core
Distribution, scale, and drivers of mass mortality events in Europe's freshwater bivalves
Conservation Biology, EarlyView.Abstract Mass mortality events (MMEs) are decimating populations and compromising key ecosystem functions around the globe. One taxon particularly vulnerable to MMEs is freshwater bivalve mollusks. This group has important ecosystem engineering capacities and includes highly threatened and highly invasive taxa.
Daniel A. Cossey +39 more
wiley +1 more source
Spectral Analysis and Application in Weak and High-frequency Signal of Optical Fiber Sensors [PDF]
, 2014 在光纤传感系统中，微弱传感信号和高频传感信号的精确检测一直是研究的热点。微弱的光纤传感信号易受到检测仪器的本底噪声或者外界环境的干扰，经常淹没在噪声中，此时无法对微小传感变量进行精确判断。现今提高光纤传感器系统检测精度的方法大都为对光纤传感器的结构进行改进或对传感信号进行时域的降噪处理。在结构改进方面可以采用低噪声高放大倍数的光电转换电路或在解调系统中引入干涉仪等，但这些方式都会增加的传感系统的成本及复杂度，特别是干涉仪的引用还会降低系统的抗干扰性。对传感信号进行降噪处理如采用小波变换 ...
陈熙
core
Conservation Biology, EarlyView.Abstract Despite the crucial role of human impacts on biodiversity loss, many assessments of this loss focus on single metrics, such as species richness, and overlook the multidimensional effects of human activities. Because of its importance to ecosystem functioning, we investigated the functional diversity of medium‐ and large‐sized mammal ...
Xueyou Li +8 more
wiley +1 more source