视觉工作记忆回溯线索效应的产生机制：认知阶段分离

以往研究关于视觉工作记忆回溯线索效应的产生机制主要存在5种假设, 目前依然存在争议。本研究通过改进前人研究实验范式, 采用包含内源性回溯线索的颜色回忆报告范式, 进一步对这5种假设进行检验。在实验1中, 我们调控了线索与探测阵列之间的时间间隔, 发现不同时间间隔不影响无线索条件的行为表现, 而在正常线索条件中被试的记忆精度以及能记住的项目数量均优于无线索条件; 在实验2中, 我们对回溯线索伴随的干扰刺激类型进行控制, 结果显示, 在不同条件下记忆精度不存在差别, 但当回溯线索伴随干扰刺激呈现时, 被试能记住的项目数量会被降低, 降低程度受干扰刺激的类型调制; 在实验3中, 我们对伴随回溯线索的干扰刺激的呈现时间进行控制, 发现虽然回溯线索效应仍然存在, 但干扰刺激的呈现时间不会影响效应程度。研究结果表明, 回溯线索的出现使得被试能够在决策加工前完成内部注意资源的再分配, 从而避免了同时进行这两种认知加工与记忆表征维持本身竞争认知资源。本研究为认知阶段分离假设提供了支持证据, 对解决回溯线索效应产生机制的争议以及理解内部注意与视觉工作记忆的关系有重要意义。     

THE FATHER,THE FATHER FUNCTION,THE FATHER PRINCIPLE: SOME CONTEMPORARY PSYCHOANALYTIC DEVELOPMENTS

The author discusses Freud's thinking on the role of the father, as well as that of later French theoreticians. To illustrate his remarks, he draws on the poetry of Carlos Drummond de Andrade (1912–1987), a Brazilian poet whose work often dealt with themes of the father, the family, and his own paternal relationship. The author also discusses the psychic formation of the father principle and how this may be evident in the clinical analytic setting, even when the analyst's approach privileges field theory, intersubjectivity, or other concepts emphasizing the relationship between analyst and patient.     

Ternary eutectic growth during directional solidification of Ag–Cu–Sb alloy

The directional solidification process of ternary Ag_42.4Cu_21.6Sb₃₆ eutectic alloy within a wide growth rate range from 2 to 60 μm/s was accomplished at a constant temperature gradient of 50 K/cm. As growth rate increases, the ternary (θ(Cu₂Sb) + ε(Ag₃Sb) + Sb) eutectic morphology evolves from “lamellar (θ + ε) plus fibrous (Sb)” structure into “(θ + Sb) fibres in continuous ε matrix” structure. The θ and (Sb) phase spacings decrease with the increase of growth rate according to power functions with exponent values of 0.55 and 0.56, respectively. It is also found that the microhardness of directionally solidified Ag_42.4Cu_21.6Sb₃₆ alloy samples is enhanced with the increase of growth rate, and the decrease of θ and (Sb) phase spacings.     

Deformed substructures in fine-grained tetragonal zirconia

Transmission electron microscopy (TEM) has been employed to examine the deformed microstructures of a high-purity tetragonal zirconia polycrystal containing 3mol% yttria. The TEM observations reveal that piled-up and tangled dislocations are developed within grains at a high stress, but such substructures do not appear at a lower stress, except for a small number of isolated dislocations. The stress-dependent deformed microstructures suggest that the dislocation substructures observed at a high stress are not due to any experimental artefacts. Applying a model proposed by Eshelby et al. to the observed pile-up dislocations, it can be estimated that a stress concentration of the order of 14-25 is generated around multiple-grain junctions during deformation.     

On anomalous channelling effects in ion-implanted silicon

Abstract

In this work results of a Monte Carlo simulation of the ion penetration in a crystalline silicon target are reported. It is shown that, contrary to the common expectation, channelling is sustained by a non-vanishing divergency of the ion beam for a nominally random orientation of the target.     

Effects of crystallization on corrosion resistance and electron work function of Zr65Al7.5Cu17.5Ni10 amorphous alloys

The effects of crystallization on the electron work function and corrosion resistance of Zr₆₅Al_7.5Cu_17.5Ni₁₀ amorphous alloys have been studied. The single-phase amorphous alloy exhibits a better corrosion resistance and has a higher work function than the partially and fully crystallized alloys with the same composition. The close relationship between corrosion resistance and work function indicates that the Kelvin probe technique can be a powerful tool for characterizing the corrosion behaviour of amorphous alloy on an electronic level.