Neutron and X-ray diffraction studies and cohesive interface model of the fatigue crack deformation behavior

The crack-tip deformation behavior during a single overload, fatigue test of ferritic stainless steel, and Ni-based HAYNES 230 superalloy is studied at different structural levels using (1) neutron-diffraction, from which both the elastic-lattice strain and volume-averaged total dislocation densities are obtained, (2) polychromatic X-ray microdiffraction to probe the geometrically necessary dislocations and boundaries distribution, and (3) an irreversible and hysteretic cohesive interface model which has been implemented into a finite element framework to simulate the stress/strain evolution near the fatigue crack tip. Neutron strain measurements and finite element simulations are in qualitative agreement on the macroscopic length scale. Large plastic deformation induced by the overload and the resulting compressive residual strains are observed in front of the crack tip after the overload, and are the principal reason for the fatigue-crack-growth retardation. Strong strain gradients surrounding the crack propagation result in the formation of a high density of geometrically necessary dislocations near the fractured surface and cause local lattice rotations on the submicron level.     

Locating dysprosium dopant atoms in the Bi2Sr2CaCu2Oy unit cell: Direct-space chemical crystallography

The position of Dy in the unit cell of Bi2Sr2CaCu2Oy has been determined by a real-space method. This is compared with the reciprocal-space atom location by channelling-enhanced microanalysis (ALCHEMI) method.     

Dependence of normal contact stress on the surface morphology of solid surfaces

Contact problems between two solids are essential to interpret the loading-unloading behaviour in indentation tests. Using linear elastic theory, a general relationship between the normal stress and the surface deformation for elastic contact of two solids was derived, in which the normal stress is a function of the mean curvature of the undeformed surface.     

Morphological study of micropits formed by anodic etching of an Al-Pd-Mn icosahedral quasicrystal

Faceted micropits obtained by electrochemical etching of a single quasicrystal of an Al-Pd-Mn icosahedral phase have been examined by optical and electron microscopy. Anodic etching of the flat surface of a fivefold plane in a solution composed of CH₃OH and HNO₃(3:1 in volume ratio) reveals a variety of icosahedrally faceted micropits which originated from pre-existing microvoids and etch pits of pentagonal pyramid shape due to the other origins, probably structural defects inside the specimen. As the dissolution progresses, the micropits make successive changes in their shapes, ending in pentagonal pyramids before they vanish.     

Mapping the time course of the positive classification advantage: An ERP study

The aim of the present study was to investigate the time course of the positive advantage in the expression classification of faces by recording event-related potentials (ERPs). Although neutral faces were classified more quickly than either happy or sad faces, a significant positive classification advantage (PCA)—that is, faster classification for happy than for sad faces—was found. For ERP data, as compared with sad faces, happy faces elicited a smaller N170 and a larger posterior N2 component. The P3 was modulated by facial expressions with higher amplitudes and shorter latencies for both happy and neutral stimuli than for sad stimuli, and the reaction times were significantly correlated with the amplitude and latency of the P3. Overall, these data showed robust PCA in expression classification, starting when the stimulus has been recognized as a face revealed by the N170 component.     

The cognitive advantage for one’s own name is not simply familiarity: An eye-tracking study

Eye-tracking technique and visual search task were employed to examine the cognitive advantage for one’s own name and the possible effect of familiarity on this advantage. The results showed that fewer saccades and an earlier start time of first fixations on the target were associated with trials in which participants were asked to search for their own name, as compared to search for personally familiar or famous names. In addition, the results also demonstrated faster response times and higher accuracy in the former kind of trials. Taken together, these findings provide important evidence that one’s own name has the potential to capture attention and that familiarity cannot account for this advantage.     

Encoding the target or the plausible preview word? The nature of the plausibility preview benefit in reading Chinese

Previous studies have shown that a plausible preview word can facilitate the processing of a target word as compared to an implausible preview word (a plausibility preview benefit effect) when reading Chinese (Yang, Wang, Tong, & Rayner, 2012; Yang, 2013). Regarding the nature of this effect, it is possible that readers processed the meaning of the plausible preview word and did not actually encode the target word (given that the parafoveal preview word lies close to the fovea). The current experiment examined this possibility with three conditions wherein readers received a preview of a target word that was either (1) identical to the target word (identical preview), (2) a plausible continuation of the pre-target text, but the post-target text in the sentence was incompatible with it (initially plausible preview), or (3) not a plausible continuation of the pre-target text, nor compatible with the post-target text (implausible preview). Gaze durations on target words were longer in the initially plausible condition than the identical condition. Overall, the results showed a typical preview benefit, but also implied that readers did not encode the initially plausible preview. Also, a plausibility preview benefit was replicated: gaze durations were longer with implausible previews than the initially plausible ones. Furthermore, late eye movement measures did not reveal differences between the initially plausible and the implausible preview conditions, which argues against the possibility of misreading the plausible preview word as the target word. In sum, these results suggest that a plausible preview word provides benefit in processing the target word as compared to an implausible preview word, and this benefit is only present in early but not late eye movement measures.     

情绪性工作记忆对选择性注意的影响

选取大学本科生33名,采用情绪启动范式与再认范式相结合,要求被试依次完成情绪词识记、目标面孔性别判断及情绪词再认任务,探讨保存于工作记忆中的情绪性刺激对面孔性别判断任务的影响。结果显示:(1)在中性和恐惧情绪启动刺激条件下,被试对目标面孔性别判断的反应时要显著长于悲伤条件。(2)在愉悦情绪启动词条件下,线索提示有效性差异显著;在无效线索提示条件下,启动刺激的不同情绪效价差异显著。(3)对情绪面孔性别与被试性别一致性/非一致性两种条件下反应时对比发现,男、女被试在情绪面孔性别判断任务中均表现出异性相吸效应。综上所述,保存在工作记忆中情绪刺激会对面孔性别的识别产生自上而下的影响。     

生存加工的编码和提取双重优势效应:ERP证据

生存加工比控制条件有更好的记忆表现,产生稳定的记忆优势,这就是记忆生存优势.已有研究多采用行为学实验验证了此现象的存在,但没有确定该优势发生在记忆的何种阶段.本研究采用ERP技术和“间接学习-再认”实验范式,比较被试在生存情境、迁徙情境和愉悦判断中对词汇编码和提取过程的记忆加工,结果发现:在500-700ms时间段,生存情境的相继记忆效应显著大于迁徙情境和愉悦判断:在400-600ms时间段,生存情境的新旧效应显著大于迁徙情境和愉悦判断.表明生存加工具有编码和提取双重优势.     

I can’t stop looking at them: Interactive effects of body mass index and weight dissatisfaction on attention towards body shape photographs

Although attentional biases toward body-related information contribute to the etiology and maintenance of body dissatisfaction (BD) and eating disorders (EDs), attentional disengagement in women with BD and EDs is not clear. The present study investigated the association between weight dissatisfaction and attentional disengagement from body-related pictures and the possible moderating effect of body mass index (BMI) on this relation. Two hundred and four undergraduate women engaged in an experiment using a pictorial spatial cueing paradigm including fat/thin bodies and neutral household photos. Partial correlations and simple slopes regression analyses were conducted with attentional disengagement index scores of each category of cues. Findings suggested that independent of BMI, weight dissatisfaction was directly associated with attentional disengagement from both fat and thin pictures. In addition, among women with low and medium BMIs, the more they were dissatisfied with their bodyweight, the more difficulty they had disengaging their attention from fat body pictures.