Results 41 to 50 of about 31,003 (237)
, 2001 总结了近几年来纳米材料的研究进展，着重从纳米材料的制备、微观结构、力学及热力学性能的研究情况作了一个概述，总结了有关纳米材料的几个研究热点以及分子动力学计算机模拟在纳米材料研究中的应用 ...
刘曰武, 周富信, 文玉华
core
Setting goals for pollinator gardens
Conservation Biology, EarlyView.Abstract In recent years, declines in animal pollinators have stimulated tremendous interest in pollinator‐friendly gardening. There is a widespread notion that pollinator gardens are beneficial, but the specific capacity of pollinator gardens to improve biodiversity conservation and societal well‐being remains unclear.
Nicholas N. Dorian +3 more
wiley +1 more source
He jishu上海硬X射线自由电子激光装置（Shanghai HIgh-repetition-rate XFEL aNd Extreme Light Facility，SHINE）具有高亮度、全相干性和高重复频率等特点。对于高重频硬X射线进行聚焦时，复合折射透镜（Compound Refractive Lens，CRL）需要承受高热负载，甚至会出现由高热应力引起的光学器件性能失效问题。为了确保CRL聚焦镜的热应力在许可限定范围内和CRL聚焦镜在高重频X射线下保持良好的光学性能，采用有限元方法（Finite ...
王 震, 佟 亚军, 刘 芳
doaj +1 more source
Vulnerability of tropical fish communities across depth in the central Indian Ocean
Conservation Biology, EarlyView.Abstract Coral reefs and their fish communities below scuba diving depth (>30 m), in mesophotic coral ecosystems (MCEs) (∼30–150 m), in rariphotic (150–300 m), and in upper bathyal waters (300–500 m) are often underexplored, especially in the Indian Ocean.
Paris V. Stefanoudis +12 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2011 本文通过在再生、普通混凝土立方体试块以及再生、普通钢管混凝土中掺加干冰和聚异氰酸盐,研究了再生、普通混凝土立方体试块的力学性能和微观性能,并研究了再生、普通钢管混凝土的力学性能。研究表明,聚异氰酸盐对钢管混凝土的改性能力不是很明显,而干冰会破坏混凝土的强度。研究还表明,再生钢管混凝土与普通钢管混凝土的抗压能力基本一致。本研究属开拓性试验研究,目前国内外还没有相关的报道。
刘轶翔, 查晓雄
doaj
Zhejiang Daxue xuebao. Lixue ban, 2001 本文在张秉坚[1]改进Barker-Henderson微扰理论的基础上，将理论推广应用到链状分子流体混合物热力学性质的计算.推导过程中采用了Wertheim[2]等人的链成键理论和类似Hino-Prausnitz[3]的流体混合法则，导出了链状方阱势分子流体混合物热力学性质的解析表达式.能够计算热力学一致的Helmhotz自由能、压缩因子、内能和恒容热容.计算结果与文献计算机模拟值吻合良好.
LIANGShi-qiang(梁世强) +4 more
doaj +1 more source
Effects of Nd element addition on microstructure and mechanical properties of Ti-6Al-4V-2Cr alloy [PDF]
, 2017 本试验采用冷等静压法及粉末冶金法制备钛合金,消除了成分偏析对合金性能的影响。在Ti-6Al-4V-2Cr中加入稀土Nd元素并进行热处理,运用光学; 显微镜、XRD和TEM对其组织和性能进行观察和分析。通过观察发现合金的组织为均匀的alpha +; beta相。运用XRD和TEM观察发现,晶界和晶内均有Nd_2O_3析出物,Nd_2O_3的出现细化了晶粒,提高了形核率,降低了晶粒尺寸。运用精; 密万能试验机进行了力学性能测试,当Nd元素含量为1%时,合金的综合力学性能最好,合金的抗拉强度提高了10.7 ...
刘冀尧 +6 more
core +1 more source
International Journal of Applied Linguistics, EarlyView.ABSTRACT Although psychological factors such as emotion and engagement have gained increasing attention for their role in language learning success, a substantial gap remains in understanding the sources of boredom and its impact on learners’ engagement, whether behavioural, affective or cognitive, in languages other than English (LOTE).
Xian Zhao, Danping Wang
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2018 罕遇地震下偏心支撑框架结构需合理有效地增大消能梁段的延性和耗能能力,并减小消能梁段的损伤,以使该种结构能更好地适应当前的抗震要求。基于剪切型消能梁段的力学特性和扩孔型螺栓连接的受剪滑移能力,提出一种扩孔螺栓连接型消能梁段。采用校正的有限元方法对扩孔型螺栓连接和扩孔螺栓连接型消能梁段进行详细分析,以明确相应试件的力学性能。研究结果表明,扩孔螺栓连接型消能梁段具有高延性和强耗能等特点,能有效提高偏心支撑框架结构的抗震性能和震后功能恢复能力,并为偏心支撑框架结构的抗震设计提供新的思路和方法。
胡淑军, 熊进刚, 宋固全
doaj
International Journal of Applied Linguistics, EarlyView.ABSTRACT E‐books, powered by multimedia and interactive features, are widely used to support young children's language and literacy development. This study examines the relations of e‐book narration and bilingual parent–child talk to children's learning during shared reading. Data from 121 English learners in China and their parents were analyzed using
Dandan Yang +3 more
wiley +1 more source