Results 21 to 30 of about 1,054,478 (169)

Nonlinear free vibration analysis of Timoshenko beams with porous functionally graded materials

open access: yesXibei Gongye Daxue Xuebao, 2022
基于Timoshenko梁变形理论研究多孔功能梯度材料梁的非线性自由振动问题。针对多孔功能梯度材料梁的孔隙均匀分布和孔隙线性分布2种形式, 根据广义Hamilton原理推导多孔功能梯度材料Timoshenko梁的非线性自由振动的控制微分方程组并对方程组进行无量纲化。采用微分变换法(DTM)对各种边界条件下的控制微分方程组进行变换, 得到等价代数特征方程。计算了多孔功能梯度材料Timoshenko梁在固支-固支(C-C)、固支-简支(C-S)、简支-简支(S-S)和固支-自由(C-F ...
TENG Zhaochun, MA Lingquan, FU Xiaohua
doaj   +1 more source

Oxygen Doping and Crystal–Amorphous Multiphase Coupling Synergistically Improve the Wear Resistance of NiTiCu Alloy

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT NiTi shape memory alloys (SMAs) show excellent performance in vibration damping and corrosion resistance. However, due to low hardness and lack of self‐lubrication, they suffer severe friction and wear during service. Although various strategies including doping and heterostructure design have been proposed, the effects are unsatisfactory.
Huwen Ma   +13 more
wiley   +1 more source

碳化硅非线性电阻导电机理

open access: yesDianci bileiqi, 1992
提出了SiC非线性电阻的导电模型.利用半导体理论分析了SiC非线性电阻的静态及动态伏安特性,认为SiC非线性电阻的伏安特性是由形成SiC非线性电阻的两大组分—SiC、结合剂共同决定的.
贺西民
doaj  

Individual Variation in Overwintering Strategies of the Great Evening Bat (Ia io) in Subtropical China 中国亚热带地区大足蝠 (Ia io) 越冬策略的个体差异

open access: yesWildlife Letters, Volume 4, Issue 2, Page 66-72, June 2026.
Tracking with GPS and accelerometers shows that great evening bats in subtropical China use two overwintering strategies: some remain in continuous hibernation, while others switch between torpor and activity as temperatures change. This behavioral flexibility, shaped by climate, underscores the importance of protecting diverse roosting habitats for ...
Zhiqiang Wang   +7 more
wiley   +1 more source

非线性负荷及其对电力系统的影响

open access: yesGaoya dianqi, 2001
介绍了非线性负荷的种类及其用电特性 ;分析了非线性负荷对电力系统及电器设备的危害 ;提出了分析非线性负荷时所采取的数学模型 ,论述了在解决实际问题时非线性负荷的处理方式。
薛军, 汪鸿, 华峰, 刘军成
doaj  

Representation of obligate groundwater‐dwelling copepod diversity in European protected areas

open access: yesConservation Biology, Volume 40, Issue 3, June 2026.
Abstract Groundwaters sustain diverse surface ecosystems and are populated by metazoan species, mostly invertebrates, that provide fundamental ecological functions and are often of prominent conservation value due to narrow endemism and high phylogenetic rarity.
Francesco Cerasoli   +7 more
wiley   +1 more source

砷酸钛氧钾铁电薄膜的研制

open access: yes四川大学学报. 自然科学版, 1998
KTiOAsO4(KTA)晶体是一种新型的性能优良的铁电晶体,它的电光效应和非线性光学效应尤为突出,使得它在光电子技术及非线性光学领域有一系列重要应用[1].KTA与另一种已知的性能出众的非线性光学材料KTiOPO4(KTP)相比,具有更高的非线性光...
廖宇, 焦志峰, 唐林昌, 徐晓非
doaj  

Biodiversity‐driven spatial conservation planning to delineate temporally stable regions

open access: yesConservation Biology, Volume 40, Issue 3, June 2026.
Abstract The accelerating loss of biodiversity underscores the critical need for effective conservation strategies, particularly in the face of climate change and anthropogenic pressures. We devised a conservation planning framework that adopts a temporal stacking approach to species distribution models and landscape connectivity analyses. These models
Mattia Iannella   +5 more
wiley   +1 more source

换流变压器阀侧绕组非线性各向异性直流电场分析

open access: yesGaoya dianqi, 2012
由于绝缘材料的电阻率具有非线性和各向异性,故在计算换流变压器阀侧绕组直流电场时需要考虑到绝缘材料的非线性和正交各向异性。笔者采用ANSYS二次开发技术,计算了在考虑绝缘材料电阻率随场强和温度变化情况下的非线性直流电场及非线性各向异性直流电场。计算结果表明,在考虑绝缘材料电阻率非线性和各向异性的情况下,电场分布与不考虑这些条件下的分布有很大的不同。因此,换流变压器阀侧绕组的直流电场应该按非线性各向异性场计算。
李晓辉   +3 more
doaj  

New Approach to Supporting Stakeholders in English Medium Instruction through a Global Online Community

open access: yesInternational Journal of Applied Linguistics, Volume 36, Issue 2, Page 1606-1614, May 2026.
ABSTRACT With the internationalisation of higher education, English medium instruction (EMI) has become increasingly common in non‐English‐speaking contexts. However, research highlights a range of challenges in EMI implementation, including insufficient collaboration between content and language teachers, limited professional development opportunities
Jingwen Zhou, Nadia Lamprecht
wiley   +1 more source

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