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221.
P. Sachenko J.H. Schneibel J.G. Swadener W. Zhang 《Philosophical Magazine Letters》2013,93(9):627-631
Grain-boundary grooving has been studied on polished surfaces of polycrystalline tungsten annealed at 1350°C. Atomic force microscopy images were taken in the same area for each groove after different annealing times. Secondary oscillations next to the main groove maxima (predicted for grooving by surface diffusion) were observed, to our knowledge for the first time. The agreement between experimental and calculated groove profiles (using the surface diffusion model of Mullins (1957, J. appl. Phys., 28, 333)) improved when grain-boundary fluxes were introduced. 相似文献
222.
The compressive deformation and fracture features of Zr59Cu20Al10Ni8Ti3 bulk metallic glassy samples with aspect ratios in the range of 0.67–2.00 have been investigated. The compressive plastic strain of the glass monotonically increases with decreasing aspect ratio, but the maximum strength almost maintains a constant value of 1.77–1.88?GPa. All the compressive shear-band angles are equal to?~40° if modified by the rotation of the primary shear bands. 相似文献
223.
The mechanical softening behaviour of micrometre-scale metals (free-standing metal foils and wires) with decreasing either the geometrical or the microstructural scale (i.e. the smaller, the weaker) has recently been reported. Here, we present a mechanism-based model to understand the softening behaviour, which is based on competition between the effects of surface grain relaxation and the interior grain strengthening effect. The model describes well the yield stress of Cu foils with different ratios of the thickness to grain size. 相似文献
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ABSTRACTThe effect of Retrieval Practice refers to the phenomenon that taking a practice test is more effective for learning than re-study, probably due to the benefit from processes underlying successful retrievals during practice. However, it is rarely studied whether other processes (e.g., metacognitive monitoring) during retrieval practice may also play an important role. In two experiments, we examined whether the effectiveness of retrieval was affected by subjects’ confidence in their retrieval success. Subjects studied word-pairs and rated their confidence after each practice test trial (cued-recall in Exp.1, multiple choice in Exp.2), or re-study trial. In both experiments, we observed the classic retrieval practice effect. Moreover, in Exp.2, the benefits differed as a function of subjects’ confidence in their retrieval performance: the effect of retrieval practice only emerged for high-confidence trials with higher than 56% confidence. In summary, the retrieval practice only facilitates the retention of correct answers with high confidence. 相似文献
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在不同领域的道德判断中,情绪可能起着“催化剂”的作用。一种特定情绪对应一种核心评价;一种情绪只影响某一道德领域的判断,不同情绪的影响是特异性的;进化心理学和具身认知对道德判断中存在的评价倾向和特异性效应进行了解释。未来研究需要探索评价倾向与特异性效应的内在心理机制。以及进一步探讨文化等第三变量对不同情绪与特定领域道德判断的影响。 相似文献
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该研究以广州市与台中市大学生为被试,抽取500人为预测样本及800人为正式施测样本,通过探索性因素分析和验证性因素分析编制生命意义量表,并通过t检验和潜在剖面分析考察两岸大学生生命意义现况的差异.结果表明:(1)编制的生命意义量表由存在意义、追寻意义、存在盈实、苦难接纳、死亡接纳以及求意义的意志等6个维度组成,具有良好的信度和效度.(2)两岸大学生生命意义总体无显著差异;存在盈实、苦难接受与死亡接纳维度有显著或非常显著的差异.(3)潜在剖面分析结果显示,两岸大学生生命意义类型相似.Wald检验结果表明,对于“死亡接纳”维度,台湾与大陆学生在各潜在类别的均分上存在显著的差异. 相似文献
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