Results 21 to 30 of about 428,911 (164)
Shuitu Baochi Xuebao, 2023 生境质量是衡量一个地区生态环境优劣的重要参考指标,土地利用变化研究可为区域生境质量时空动态演变特征评估提供科学依据。基于1980年、2000年、2018年土地利用数据,通过InVEST模型、PLUS模型、地理信息图谱法分析并预测榆林市土地利用变化情况,以此探究陕西省榆林市生境质量时空演变特征。结果表明:(1)榆林市景观基质主要由草地和耕地构成,林地和未利用地次之,水域和建设用地占比相对较少,退耕还林政策的实施、治沙工程的开展,以及建设用地的开发是土地利用变化的主要驱动因素。(2)从区域整体分析 ...
冀泳帆 +4 more
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Overreliance on Orthographic Similarity in L2‐Japanese Conceptual Processing by L1‐Chinese Learners
International Journal of Applied Linguistics, Volume 36, Issue 2, Page 1807-1820, May 2026.ABSTRACT Orthographic and phonological similarities between first (L1) and second (L2) languages can facilitate L2 processing. Particularly, L1‐Chinese learners of L2‐Japanese can benefit from the shared morphosyllabic Chinese characters (Japanese kanji/Chinese hanzi) because of their similar orthographies.
Xuehan Zhao, Kexin Xiong, Sachiko Kiyama
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Gaoya dianqi, 2023 阴极弧根为电子发射的主要区域，弧根的运动对空气直流电弧等离子体特性有重要意义。通过电极旋转驱动阴极弧根运动，实验观测得到电极旋转情况下空气直流电弧拉弧过程电极表面烧蚀情况、扭曲的弧柱形态，同时提取并对比了直线拉弧和旋转拉弧的电弧电压上升曲线。参照临界电流试验条件，建立小电流下平行电极间三维电弧仿真模型，探究在小电流情况下，自由燃烧态电弧的演变过程。仿真结果表明：阴极弧根运动使得发射后极间带电粒子空间分布变化，间隙放电通道改变，电弧的最大温度值降低；当电弧放电通道不稳定时，极间电弧电压出现波动 ...
付思, 陈文清, 曹云东
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Politics &Policy, Volume 54, Issue 2, April 2026.ABSTRACT This study employs advocacy coalition framework (ACF) theory to analyze debates over U.S. space policies designed to avoid dangerous collisions between objects in Earth orbit. For decades, the Department of Defense prioritized national security in its development of space traffic coordination (STC) systems like the Space Surveillance Network ...
Jeffrey S. Lantis
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Evolution of research on global amphibian declines
Conservation Biology, Volume 40, Issue 1, February 2026.Abstract In the late 1980s, the scientific community became aware of severe, enigmatic amphibian population declines. These declines triggered a wave of research focused on quantifying their extent and identifying key drivers. We used text‐analysis techniques, including topic modeling and geoparsing, to examine the evolution of research focused on ...
Jordann Crawford‐Ash +6 more
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Kongjian kexue xuebao, 2023 小天体检测是小天体防御和预警的前提。针对小天体目标信噪比低、检测难的问题，提出了基于统计特征空间提取和支持向量机（SVM）的极暗弱小天体检测方法。区别于传统方法基于时间或空间上目标的能量和背景噪声能量的瞬时能量差别或是瞬时能量差别的累积，对目标进行检测。该方法不依赖目标能量大小，提取运动目标穿过背景时对稳定性产生的扰动来反演运动目标。将输入的图像序列转化为单像元时序信号，划分时序窗口提取统计特征，关联形成统计特征空间，利用更高维度的变化特性检测目标变化 ...
王 存远, 郑 伟, 李 明涛
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Rare Metals, Volume 45, Issue 1, January 2026.ABSTRACT High‐entropy alloys (HEAs) have emerged as a transformative class of materials distinguished by their complex chemical compositions, unique microstructures, and remarkable mechanical and functional properties. Traditionally, the discovery and optimization of HEAs have relied on conventional methods, including trial‐and‐error experimentation ...
Chrispin Ouko Zamzu +2 more
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The Rhetoric of Disenchantment: Ghost Belief and Secular Critique in Early Twentieth‐Century China
Cognitive Science, Volume 50, Issue 1, January 2026.Abstract This study presents the first large‐scale empirical analysis of how ghosts and spirits were debated during China's early twentieth‐century secular transformation. Using a novel dataset of over 2000 digitized texts—including newspapers, periodicals, and essays from 1890 to 1949—we combine close reading, AI‐assisted annotation, and statistical ...
Ze Hong, Yuqi Chen
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Shuitu Baochi Xuebao, 2006 在一个较小的时空尺度上对典型喀斯特地区石漠化过程中的土壤质量演变特征及其退化过程进行了探讨。结果表明：由于植被破坏和耕地的开垦发生土壤颗粒粗化，向石漠化景观发展，土体结构破坏，容重增加0．12～0．60g／cm^3，总孔隙度降低12．0％～39．8％，持水性能变劣，养分也随之下降；〈0．05mm的粘粉粒流失，表层土壤有机质和全氮含量下降33．4％～84．6％和43．3％～85．2％。土壤质量的演变，既有系统本身的自然属性决定的内在原因，更重要的是人为的外部干扰体系的驱动；演变的过程既有渐变型，又有跃变型。
龙健, 李娟, 汪境仁, 李阳兵
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Zhejiang Daxue xuebao. Lixue ban, 2019 闪电事件时空变化研究对于防灾减灾和资源利用具有重要意义。采用2 481 个站点的闪电日数数据诊断 1961—2016 年我国闪电事件的时空演变特征。结果表明：在时间上，1961—2016 年我国年均单站闪电日数整体呈减少趋势，西北西部和西藏地区年均单站闪电日数呈分段变化特征。全国、东北、北方、西北东部和东南地区年均单站闪电日数大致呈2~4 a 的周期变化。西北西部、西藏和西南地区分别呈2，4 和6 a，3 和8 a 与2~6 a 的显著周期变化。年均单站闪电日数突变集中发生在20 世纪80 年代末至90
KONGFeng(孔锋) +4 more
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