Results 21 to 30 of about 1,058,102 (105)

A Latent Profile Analysis of Chinese EFL Students’ Speaking Self‐Efficacy: The Role of Gender in Predicting Profile Membership and the Association of Profiles With Speaking Proficiency

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT Understanding learners’ English speaking self‐efficacy is essential for promoting effective oral communication in EFL contexts. However, variable‐centered research on English speaking self‐efficacy often overlooks heterogeneity among learners.
Cha Li, Lawrence Jun Zhang
wiley   +1 more source

Addressing the Right to Food Through Food Expenditure Burdens: Distributional Evidence Among Low‐Income Farming Families in Brazil (2012–2023)

open access: yesWorld Food Policy, Volume 12, Issue 2, November 2026.
ABSTRACT Household food expenditure continues to be a key factor in ensuring the realization of the Human Right to Adequate Food. Particularly in Brazil, access to food can be limited by economic constraints in vulnerable families, especially among farming families, who have been more vulnerable to food insecurity in recent years in the country.
Lucas de Almeida Moura   +3 more
wiley   +1 more source

Designing Integrated Policies for the Twin Transition: Challenges and Tradeoffs

open access: yesPolicy Studies Journal, Volume 54, Issue 4, November 2026.
ABSTRACT Democratic governance faces the intertwined imperatives of managing the transformative risks and opportunities of digitalization, particularly stemming from artificial intelligence (AI), while achieving environmental sustainability within planetary boundaries.
Martino Maggetti
wiley   +1 more source

用子波变换研究壁湍流Lipschitz奇异性指数

open access: yes, 1998
本文用子波变换研究了描述壁湍流脉动速度局部奇异性行为的Lipschitz奇异性指数,发现在湍流边界层中 ...
王振东, 舒玮, 姜楠
core   +1 more source

纵向岭谷区植被特征参数的空间变异 [PDF]

open access: yes, 2006
采用GPP(总初级生产力)、NPP(净初级生产力)、NDVI(归一化植被指数)、EVI(增强型植被指数)四项表征植被特征的参数,对中国西南纵向岭谷区植被特征参数的空间变异性进行分析.采用Moran系数(MC)对植被特征参数的空间自相关程度进行度量,采用半变异函数进行西南纵向岭谷区植被特征参数的空间分异及其结构特征研究.研究结果表明:(1)植被特征参数在全局范围内呈现负的空间自相关,各向异性自相关程度均表现在南-北方向自相关程度较大,其次为东南-西北方向;(2)植被特征参数的空间变异尺度较大;(3 ...
戴尔阜   +5 more
core   +1 more source

火焰发射光谱法定量测定人血清锂的研究——附43例广州地区正常成人血清锂含量测定

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 1987
采用火焰发射光谱法对人血清锂的定量测定进行了研究。实验表明,溶液中锂的检出限为0.4μg/l,浓度与光密度的关系符合Lambert-Beer定律,呈直线正相关(r=0.999995 ...
冼汉隆
doaj  

In‐Situ Construction of Multi‐Scale Heterogeneous Structures in L‐DED IN718 Coatings via WMoTaNb Incorporation for Enhanced Strength‐Toughness Synergy

open access: yesRare Metals, Volume 45, Issue 10, October 2026.
ABSTRACT To improve the strength–toughness balance of IN718, and alleviate the brittleness commonly associated with refractory high‐entropy alloys, this study proposes a novel strategy to fabricate defect‐free IN718/WMoTaNb heterogeneous multiprincipal element alloy coatings via laser‐directed energy deposition.
Zhao Wang   +7 more
wiley   +1 more source

Ultrasonic Vibration Assisted Laser Processing: A Hybrid Paradigm for Extreme Surface Enhancement

open access: yesRare Metals, Volume 45, Issue 10, October 2026.
ABSTRACT Traditional laser processing techniques offer many advantages, but they often encounter limitations such as heat‐affected zones, recast layers, residual tensile stresses, and poor surface finish. The integration of ultrasonic vibration (UV) presents a promising hybrid approach to overcome these challenges by introducing beneficial effects like
Aziz Ul Hassan Mohsan   +6 more
wiley   +1 more source

黄土高原退耕坡地土壤水分空间变异的尺度性研究

open access: yes, 2005
在面积60m×60m的坡地上采用2m×2m的网格进行高密度土壤水分测定,通过改变采样幅度和采样间距的“再采样”方法,选取变异系数、相关距离和Moran的I相关指数3个参数作为表征空间变异大小的指标,研究了尺度大小对土壤水分空间变异的影响。研究结果表明,随着采样幅度尺度在一定范围内的增大,土壤水分变异的特征参数如变异系数、相关距离和Moran的I相关指数都呈不同程度地增大;当采样间距增大时,变异系数和Moran的I相关指数没有变化 ...
胡伟, 邵明安, 王全九
core   +1 more source

不同利用方式下红壤坡地土壤水分时空动态变化规律研究

open access: yesShuitu Baochi Xuebao, 2006
利用连续3年土壤水分定位观测数据,研究了红壤坡地不同利用方式下土壤水分的时空动态变化规律。结果表明:土壤水分时空动态变化主要受降雨和植被类型的影响。土壤水分季节变化分为相对稳定期、消耗期和补给期三个时段;土壤剖面(0~90cm)水分含量从表层到深层表现为增长型,依据2003年土壤水分标准差和变异系数。将土壤剖面划分为活跃层、次活跃层和相对稳定层3个层次;土壤剖面水分变异系数随降雨量和土层深度的增加而减小,随植被根系的增长而变大。平水年,深根系区与浅根系区土壤水分变化差异表现在30cm深度以下 ...
王晓燕   +3 more
doaj  

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