Results 11 to 20 of about 9,264 (142)
International Journal of Applied Linguistics, EarlyView.ABSTRACT Collaborative writing has attracted increasing attention in English as a Foreign Language (EFL) instruction due to its potential to enhance learners’ writing competence. However, few studies have examined the comparative effects of collaborative versus independent writing on EFL learners’ individual performance, especially in higher‐order ...
Ting Huang, Chenze Wu, Wenkang Zhang
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Cs2SnI6: A Perovskite‐Based Electromagnetic Wave Absorbing Material
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT Lead halide perovskites and carbon‐based materials are interesting, high‐performing electromagnetic wave absorbing materials. However, only a few studies have been carried out to examine in detail the electromagnetic wave absorption properties of these materials.
Fei Han +11 more
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, 2018 为摩托车头盔的安全性设计,需要研究在冲击载荷下内衬泡沫的能量吸收能力对摩托车头盔防护性能的影响。该文建立了有限元数值分析头盔模型,依据欧洲经济委员会(ECE)的法规ECE R22.05的动态测试方法,验证该模型的有效性。改变头盔不同测试点下的泡沫密度,进行了12个跌落的仿真试验。结果表明:在头盔的前部、冠部和后部测试点区泡沫密度由40 kg/m3增加到80 kg/m~3时,泡沫的能量吸收能力逐渐增大,头部冲击能量衰减得更快,导致3个测试点头部颅骨骨折的风险从25%、55%、39%分别增大至53%、96%、
何伟 +4 more
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Gaoya dianqi, 2022 直流断路器是柔性直流输电系统组网的关键设备，对直流输配电网的安全性、稳定性有着重要的意义。文中提出了一种基于绝缘栅双极型晶体管（insulated gate bipolar transistor,IGBT）的新型固态直流断路器拓扑，在提高断路器切断电流能力的同时，提高了避雷器和IGBT的使用寿命。通过引入接地引流二极管，减轻避雷器吸收能量的压力，加快电流分断的速度。基于所提拓扑设计了10 kV的直流断路器模型，在PSCAD/EMTDC中进行了验证，仿真结果表明：基于所提出的方案，最大开断电流可达5kA ...
丁璨 +4 more
doaj
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT Lightweight and lead‐free radiation shielding materials remain urgently needed. This work designed a fluorite high‐entropy oxide (FHEO) system through a combined computational–experimental route. Density functional theory based on special quasi‐random structures was used to identify thermodynamically stable fluorites from a wide compositional ...
Xiangjie Duan +9 more
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Investigations of Nucleation Mechanism in Initial Period for Direct Electroless Nickel-boron Plating on Magnesium Alloy and Electrochemical Properties of Plating Solution [PDF]
, 2009 镁合金具有优良的性能，但是其耐蚀性差的特点限制了在生产和生活方面的广泛应用。本文研究了前处理后镁合金表面状态的变化，并利用扫描电子显微镜（SEM）、X射线衍射仪（XRD）、划痕试验以及电化学方法等技术综合表征在最优工艺条件下获得的镀层的形貌、结构、结合力和耐蚀性等性能。采用元素分析和镀层形貌相结合的方法探讨镀层初期形核机理。运用电化学手段，利用循环伏安技术研究了不同镀液组分浓度以及不同电极表面对镀液电化学性能的影响。 研究结果表明酸洗处理后，镁合金表面获得了一层银白色且具有网状结构的氧化膜 ...
彭淑合
core
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT The high operating temperatures and sluggish kinetics of Mg‐based hydrogen storage materials (HSMs) are urgently being addressed. In this work, a novel Mg–Ni–Ga HSM with dual‐phase synergistic catalysis is developed, including the fishbone‐like Mg3Ni2Ga1 catalytic phase and the Mg2Ni phase with stacking faults (SFs).
Shiyang Hu +7 more
wiley +1 more source
Optimization simulation and crushing experiment of anti-impact energy absorption component of hydraulic support column [PDF]
Hydraulic support, being the primary supporting equipment in coal mining operations, is frequently subjected to rock burst pressure. Hence, the anti-impact energy absorption components play a pivotal role in safeguarding the hydraulic support system ...
Liyong TIAN +4 more
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Rare Metals, Volume 45, Issue 3, March 2026.ABSTRACT In conventional piezoceramics, the coordinated change between the dielectric constant (εr) and the piezoelectric charge constant (d33) usually limits the piezoelectric voltage constant g33 (g33 = d33/εr), a critical figure of merit for piezoelectric sensors.
Xiaoying Feng +7 more
wiley +1 more source
Dianci bileiqi, 2018 金属氧化物避雷器作为过电压保护设备,对电力系统绝缘配合起着关键作用。金属氧化物避雷器的能量吸收能力是避雷器的重要特征性能,决定着其保护特性和自身的运行安全,已引起使用部门和制造者的普遍关注。避雷器的能量吸收能力主要取决于电阻片的能量吸收能力,在运行和试验过程中,电阻片会有哪些破坏形式,哪些因素会影响到电阻片的能量吸收能力,本文对此进行初步试验探讨。试验结果显示,电阻片的主要破坏形式有贯穿、开裂、闪络,影响电阻片能量吸收能力的主要因素有电阻片的起始温度、热容量、能量注入的形式。
艾三 +5 more
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