Timing of hydrologic anomalies direct impacts on migration traits in a flood pulse fishery system
We designed a spectral analysis framework to quantify hydrological variation and linked it with fishery harvest records. Quantified effect sizes of hydrologic anomalous events demonstrated one designed hydrograph for fishery benefits: properly timed prolong drought followed by a strong flood pulse.
Qi Deng +4 more
wiley +1 more source
Numerical Simulation And Experiment Study On Magnetoacoustic Emission with Magnetic Induction [PDF]
铝合金板材具有高强度、低密度、强耐腐蚀、高断裂韧性和良好的高低温特性等优点,是制造宇宙飞船、运载火箭、飞机、舰船、坦克、装甲车和高速列车的主要材料。然而,由于加工工艺限制,铝合金板材在生产过程中不可避免地存在分层、夹杂、裂纹和氧化膜等缺陷。无损检测技术是一种在不破坏待测物材质与性能前提下实现构件质量检测的技术,目前已在许多领域成为确保产品质量和可靠性的强制性措施。 本文研究的感应式磁声发射无损检测方法是利用线圈在导体感应出的涡流在静态磁场的作用下会受到洛仑兹力的作用使导体发生机械振动,进而产生磁声信号 ...
李超
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How Many Floods Have Occurred in China in the Past Decade? A Perspective From Social Media
Abstract Global climate change has led to frequent and widespread flood disasters in China. Traditional flood disaster investigations mainly focus on major flood events, and small‐scale flood events are often overlooked. This study utilized the Sina Weibo social media platform to detect flood events in 370 cities in China from 2012 to 2023.
D. Shen +5 more
wiley +1 more source
Effects of transcutaneous electrical nerve stimulation on the regional cerebral blood flow of subjects with stroke : a preliminary study [PDF]
2004-2005 > Academic research: refereed > Publication in refereed journalVersion of ...
Guo, Y, Hui-Chan, CWY, Lu, XP, Yan, T
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The Research on Steel Plate Defects Inspection by Magneto-acoustic Testing with Induction [PDF]
随着工业化的发展,钢材被应用在了各种各样的领域,比如:天然气管道、轮船、汽车等等。然而,随着时间的推移,钢材在使用过程中会出现腐蚀、裂纹等缺陷,这些缺陷严重影响了使用的安全,所以必须在事故发生之前对其进行检测以评估其安全性。本文在对比多种无损检测方法及研究感应式磁声成像的基础上提出了感应式磁声检测的新方法。该方法是在静态磁场下,通过脉冲电流激励被测钢板表面,进而在钢板内部发生电-磁-声的相互转化,最后提取钢板表面的磁声信号。该方法与被测材料无接触,无耦合,可在恶劣环境下进行工作,非常适合钢板的在线检测。
游德海
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Design of the Series-saturated Constant-current Drive Circuit based on Analyzing the lighting Characters [PDF]
发光二极管(lEd)技术的快速发展使其在照明工程中的应用越来越广泛。针对lEd照明的特点和光学特性参数,从驱动电路入手,设计了一款照明灯实用lEd驱动电路,并将理论分析结果与lEd驱动电路的实际测量结果进行了对比,对比结果表明,该驱动电路具有实用性,既能满足照明工程的功能性要求,又能够实现最大限度的节能。The rapid development of light emitting diode(LED) technology allows it applying in lighting projects
王雅芳
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Implementation of Laser Diode Characteristics Pulsed Testing by Time-resolved Technique [PDF]
提出了一种基于时间分辨的脉冲式半导体激光器特性测试新方法,并研制了相应的测试系统。该方法根据脉冲驱动源的时序,同步产生采样窗口信号,然后根据采样窗采集半导体激光器的注入电流、端电压和输出光功率等数据,进而获得表征器件特性的曲线和参数。该方法解决了半导体激光器特性测试中的2个关键问题:一是现有的连续测试方法造成的器件温升,影响测试准确性和安全性;二是解决了脉冲驱动源与测试的同步问题。文中给出了最小脉冲宽度达100 nS的窄脉冲驱动的l-I-V测试曲线和测试参数。A new method to test ...
孙颖, 左勇, 范贤光
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Study on Technological Characteristics of High Frequency Short Pulse Electrochemical Finishing [PDF]
阐述了高频窄脉冲电化学光整加工原理;比较了其与脉冲电化学加工的区别与联系;通过实验,研究及分析了电流密度、加工间隙、工件材料、加工时间及脉冲参数等因素对加工后表面质量的影响。实验结果表明:在合适的工艺参数情况下,高频窄脉冲电化学光整工艺可大幅度提高加工效率,获得镜面级的表面质量,并能降低加工成本。Surface finishing(or polishing)is a tedious and necessary finishing operation for many products.In this ...
刘晓梅 +3 more
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Fabrications and Characterizations of Porous Silicon by Two-step Techniques II: Pulse Current Application [PDF]
采用脉冲阳极 /阴极电流和化学氧化两步法分别在 1∶1的氢氟酸和乙醇溶液中及 2 0 %硝酸溶液中制备出孔径约为 0 .5~ 3μm ,厚度大约为 10~ 2 0 μm的多孔硅样品 ,将获得的多孔硅结构再进一步用扫描电子显微镜和拉曼光谱仪进行表面形貌和光学性质的考察 .与恒电流 -化学氧化两步法制得的多孔硅相比 ,用脉冲电流法得到的多孔硅的孔径范围较大 ,且多孔层较厚 .制备时加紫外光照显著提高了多孔硅的厚度 ,并发生“蓝移”现象 .用脉冲电流法制得的多孔硅在老化后 (在干燥器放置一年 ...
CHENG Xuan +11 more
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Research Progress in the Fabrication of Metal Matrix Composites by Electrochemical Methods [PDF]
[中文文摘]金属基复合材料具有高比强度、高比模量、高硬度、耐高温等一系列优点,在现代航空、航天及武器装备等领域具有广阔的应用前景。综述了近年来电化学方法制备金属基复合材料的研究进展,具体介绍了电化学渗浸、连续分步电沉积和复合电沉积3种不同的电化学工艺过程。[英文文摘]Metal matrix composites have excellent properties including high specific strength, modulus, hardness and heat ...
倪永金, 唐毅, 王周成
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