Synthesis of a single phase of high-entropy Laves intermetallics in the Ti–Zr–V–Cr–Ni equiatomic alloy

The high-entropy Ti–Zr–V–Cr–Ni (20 at% each) alloy consisting of all five hydride-forming elements was successfully synthesised by the conventional melting and casting as well as by the melt-spinning technique. The as-cast alloy consists entirely of the micron size hexagonal Laves Phase of C14 type; whereas, the melt-spun ribbon exhibits the evolution of nanocrystalline Laves phase. There was no evidence of any amorphous or any other metastable phases in the present processing condition. This is the first report of synthesising a single phase of high-entropy complex intermetallic compound in the equiatomic quinary alloy system. The detailed characterisation by X-ray diffraction, scanning and transmission electron microscopy and energy-dispersive X-ray spectroscopy confirmed the existence of a single-phase multi-component hexagonal C14-type Laves phase in all the as-cast, melt-spun and annealed alloys. The lattice parameter a = 5.08 Å and c = 8.41 Å was determined from the annealed material (annealing at 1173 K). The thermodynamic calculations following the Miedema’s approach support the stability of the high-entropy multi-component Laves phase compared to that of the solid solution or glassy phases. The high hardness value (8.92 GPa at 25 g load) has been observed in nanocrystalline high-entropy alloy ribbon without any cracking. It implies that high-yield strength (~3.00 GPa) and the reasonable fracture toughness can be achieved in this high-entropy material.     

Against the “system” module

Modularity is a fundamental doctrine in the cognitive sciences. It holds a preeminent position in cognitive psychology and generative linguistics, as well as a long history in neurophysiology, with roots going all the way back to the early nineteenth century. But a mature field of neuroscience is a comparatively recent phenomenon and has challenged orthodox conceptions of the modular mind. One way of accommodating modularity within the new framework suggested by these developments is to go for increasingly soft versions of modularity. One such version, which I call the “system” view, is so soft that it promises to meet practically any challenge neuroscience can throw at it. In this paper, I reconsider afresh what we ought to regard as the sine qua non of modularity and offer a few arguments against the view that an insipid “system” module could be the legitimate successor of the traditional notion.     

心理理论的ERP研究:基于多重成分框架的视角

心理理论是社会认知的核心能力之一。现有的心理理论ERP研究以心理理论较为公认的4个成分信念、愿望、意图和情绪为框架,表现出了一些一致性的规律:心理理论相关的脑电成分根据不同的心理理论成分而有所区分;不同心理理论成分诱发的相关脑电出现的位置表现出跨任务的一致性;心理理论的ERP发展研究在儿童身上表现出与成人类似的结果,但也具有时间窗口更长,位置分布更宽广的特性。未来的研究需要设计出更符合ERP研究技术要求的任务范式,并注意心理理论概念结构的完整性,还应探寻心理理论各成分加工的共同电生理基础。     

产后抑郁的预测因素及神经生理机制

产后抑郁是产后时期出现的抑郁症状,对女性及其后代甚至家人都会造成严重的负面影响。产后抑郁稳定的预测因素是遗传基因、依恋风格、童年负性生活经历和激素水平的变化;涉及的脑区和神经网络集中在前额叶皮层、扣带回、杏仁核和海马等脑区及相应神经网络。未来应在探索综合的预测模型、男性伴侣的对照试验和基于大脑可塑性特征的干预模式等方面展开深入研究。     

情绪影响行为抑制的脑机制

行为抑制是一种重要的执行功能。考察情绪影响行为抑制的脑机制, 将有助于理解个体如何适应环境, 特别是如何在情绪情境中控制自己的行为。近年来, 研究者开始使用脑成像技术考察情绪影响行为抑制的脑机制。研究发现, 在情绪影响行为抑制的过程中不仅涉及前额叶抑制控制系统和边缘结构情绪加工系统, 而且涉及这两个系统的相互作用, 即情绪加工与行为抑制加工的整合。腹外侧前额皮层、背外侧前额皮层、前扣带回、杏仁核、脑岛等脑区在情绪加工与行为抑制加工的整合中起着重要的作用, 但情绪整合到行为抑制加工中的时间进程还不清楚。今后的研究应着眼于情绪影响行为抑制的时间进程、神经网络、个体差异的影响以及改进研究范式等方向。     

Social representations of refugees: Place of origin as a delineating resource

This study investigated social understandings of refugees from Africa in a regional town in NSW, Australia. Drawing from Social Representations Theory (Moscovici, 1984 ), the study investigated whether place of origin (Africa) mediated understandings held about refugees. Two studies were conducted. In the first study, a between‐subjects manipulation using word association tasks revealed that the super‐ordinate term Refugees, and Refugees from Africa shared a common core of elements (poor, war). Although sharing a core, these representations were differentiated by peripheral elements which concurred with social understanding of Africa (e.g. disease), and media portrayal of refugees/asylum seekers (e.g. boat). The salience of these meanings in the community was further explored using a self‐report questionnaire. Results suggested that place of origin, manifested as peripheral representational elements, may play an important role in differentiating, orientating and linking specific refugee groups to particular socio‐political contexts. Further, we contend that place of origin may be understood as a discursive resource, deployed for rhetorical ends. Copyright © 2009 John Wiley & Sons, Ltd.     

人工神经网络在临床应用中的伦理思考

现代临床医学中的海量信息具有非线性特质,人工神经网络的自我学习、记忆和归纳功能,刚好适应了医学的新发展,在医学领域有良好的应用前景。事实上,人工神经网络临床应用的理论研究成果丰富,但商业应用并不多见。本文探讨人工神经网络在临床应用中可能引发的社会伦理争议,对其临床适用范围进行初步的论述。     

Lumen Gentium No. 8, and Subsistit in, Again

Francis A. Sullivan says that the one Church of Christ continues to exist perfectly in the Catholic Church, and is present imperfectly in other churches and ecclesial communities. However, he thinks Lumen Gentium 8 also enables us to say that the many churches, non-Catholic and Catholic, are all in the one Church of Christ, since to say the one Church of Christ subsists in the Catholic Church means no more than "continues to exist in" the Catholic Church. In this way, he denies the identity of the one Church of Christ and the Catholic Church. We point out that magisterial documents since Vatican II have consistently refused this proposal, and have instead spoken only of the one Church being present or operative, according to degrees, in non-Catholic churches and communities. We argue that while it is true there is "ecclesial reality" outside the Catholic Church, in that there are elements of truth and sanctification outside of her, the one Church of Christ of which Vatican II expressly speaks is the Church with all the gifts of unity and instruments for salvation with which Christ endowed it. The Catholic Church is not contained in any larger divinely willed and dominically instituted ecclesial reality, and it is without qualification the one Church of Christ and the one Church of Christ is without qualification the Catholic Church.     

内隐记忆中通道效应的认知与神经机制

通道转换是使内隐和外显记忆任务之间产生功能性分离经常操纵的典型变量之一,被看作是内隐记忆主要依赖刺激知觉住处加工的有利语气。该文回顾了近些年通道效应实验和理论研究的有关文献。对产生通道效应的认知机制和神经解剖基础进行了总结和分析,并提出了有待于进一步验证的问题。     

Understanding Cognition Through Large-Scale Cortical Networks

An emerging body of evidence from a number of fields is beginning to reveal general neural principles underlying cognition. The characteristic adaptability of cognitive function is seen to derive from large-scale networks in the cerebral cortex that are able to repeatedly change the state of coordination among their constituent areas on a subsecond time scale. Experimental and theoretical studies suggest that large-scale network dynamics operate in a metastable regime in which the interdependence of cortical areas is balanced between integrating and segregating activities. Cortical areas, through their coordination dynamics, are thought to rapidly resolve a large number of mutually imposed constraints, leading to consistent local states and a globally coherent state of cognition.