Results 21 to 30 of about 1,145,122 (162)
, 1990 本文提出一种有效的边界单元法计算技术,用于复合材料的各向异性板.利用正交各向异性材料在静水压力下的解析解计算奇异积分。并结合一种专门的数值积分技术 ...
王震鸣, 张恒
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Conservation Biology, Volume 40, Issue 3, June 2026.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
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, 2006 频率副词是用于表示事情、行为、动作等发生频率的副词。这类副词内部往往呈现出的较大共性,在以往的本体研究中较少被细化。在对外汉语教学中,仅仅满足于对共性的掌握并不能使外籍学生很好的掌握这类副词。本文以“屡次、一再、再三”一组近义词为例,采用计量语言学的研究方法,基于语料库语料,考察了它们在与动词组合时的语义选择条件,并兼顾了影响其选择的句法、语体等方面的因素。分析结果表明:频率副词的各种选择表现虽有大同 ...
王敏
core
Rare Metals, Volume 45, Issue 5, May 2026.ABSTRACT In recent years, materials capable of achieving efficient electromagnetic wave (EMW) absorption over a broad frequency range have attracted widespread attention. Such materials are not only significant in mitigating electromagnetic interference and pollution caused by the extensive use of electronic devices but also demonstrate outstanding ...
Maoxia Lu +7 more
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International Journal of Applied Linguistics, Volume 36, Issue 2, Page 979-994, May 2026.ABSTRACT Previous research has established the relationships between motivation, anxiety, teachers’ support, and self‐regulated learning (SRL) in English‐as‐a‐foreign‐language (EFL) learning. Most of the studies, however, have taken a variable‐centered approach in addressing the variable correlations, while learners’ characteristics and variable links ...
Yuhong Jiao, Barry Bai, Jing Li
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基于模型预测控制的光储发电系统VSG频率控制方法 [PDF]
, 2022 随着光伏发电装机规模大幅提升，电力系统转动惯量不断降低，虚拟同步发电机（virtual synchronous generator，VSG）技术被广泛采用以应对日益严峻的电网稳定性问题。为进一步提高VSG技术对系统稳定性的改善作用，提出基于模型预测控制的VSG频率控制方法。该方法首先在同步发电机转子运动方程和逆变器下垂控制方程基础上建立VSG可优化的离散模型，再通过模型预测控制（model predictive control，MPC）预测VSG转子角频率的运动轨迹 ...
张志丹 +3 more
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四川大学学报. 自然科学版, 2014 本文提出了一种基于分块离散余弦变换(DCT)、奇异值分解(SVD)和粒子群优化算法(PSO)的鲁棒视频水印方案.在其嵌入方案中,利用DC系数和奇异值的稳定性,首先将帧内所有块的DC系数置乱,并进行4×4奇异值分解,调制第3大奇异值实现水印的嵌入,由粒子群优化算法得到合适的水印嵌入强度.实验结果表明,相对于固定的嵌入强度,采用粒子群优化算法可以在保持原有视频序列视觉质量的基础上,提高水印自身的鲁棒性.同时算法能够有效抵抗H.264压缩.
吴锡溪, 王宏霞, 黄安安
doaj
Zhongguo tingli yuyan kangfu kexue zazhi, 2021 目的探讨传统226Hz鼓室图结果为C型儿童的宽频能量吸收率特征,对C型鼓室图在环境压力(0dapa)及宽频峰压下能量吸收率特征进行分析,建立C型鼓室图宽频声能吸收率曲线范围。方法选取正常耳140耳及传统226 Hz鼓室图负压耳187耳,通过宽频声导抗测试获取环境压力(0dapa)及宽频峰压下107个频率下的声能吸收率,绘制C1和C2二组儿童宽频峰压与环境压力(0dapa)下声能吸收率均值曲线,并对所有曲线进行分析。选取并分析226Hz和1/3倍频程共17个频率下A组、C1组 ...
王璐 +8 more
doaj
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT The inherent trade‐off between high saturation induction (Bs) and low core loss in soft magnetic materials presents a challenge in the development of high‐frequency power electronics. Here, a processing approach that combines accelerated Cu ordering with dual magnetic anisotropy control in high‐Bs Fe‐based nanostructured cores is examined ...
Xiaoying Li +11 more
wiley +1 more source
Automating the analysis of public saliency and attitudes toward biodiversity from digital media
Conservation Biology, Volume 40, Issue 2, April 2026.Abstract Measuring public attitudes toward wildlife provides crucial insights into human relationships with nature and helps monitor progress toward Global Biodiversity Framework targets. Yet, conducting such assessments at a global scale presents challenges.
Noah Giebink +8 more
wiley +1 more source