Log-normal nanograin-size distributions in nanostructured composites

A key challenge in the fabrication of superhard nanocomposite films is how to control the distribution of grain sizes in these materials. High-resolution transmission electron microscopy has been used to measure nanograin-size distributions in the Ti–B–N films with various B contents. The results show that the mean grain size decreases with increase of B content and the grain-size distribution conforms to a log-normal function when the hardness approaches a maximum value. The transition from normal to log-normal distributions can be determined by analysis in terms of a minimum information criterion. The origin of a log-normal size distribution probably results from heterogeneity arising from a diffusion-drift process.     

Mechanical-milling-induced amorphization of Se: A crystallite destabilization model

Complete solid-state amorphization has been realized in elemental Se by means of mechanical milling of crystalline Se powder. Quantitative X-ray diffraction and thermal analyses were employed to characterize the amorphization process and indicated that the amorphization onset corresponds to a critical crystallite size and a drop in microstrain. During the major amorphization process, the remaining crystallite size remains unchanged with a constant lattice expansion. A new kinetics model of crystallite destabilization is proposed for the solid-state amorphization which satisfactorily explains the experimental observations.     

Fractals and scaling in fracture induced by microcrack coalescence

A numerical model is proposed to simulate fracture induced by the coalescence of numerous microcracks, in which the condition for coalescence between two randomly nucleated microcracks is determined in terms of a load-sharing principle. The results of the simulation show that, as the number density of nucleated microcracks increases, stochastic coalescence first occurs followed by a small fluctuation, and finally a newly nucleated microcrack triggers a cascade coalescence of microcracks resulting in catastrophic failure. The fracture profiles exhibit self-affine fractal characteristics with a universal roughness exponent, but the critical damage threshold is sensitive to details of the model. The spatiotemporal distribution of nucleated microcracks in the vicinity of critical failure follows a power-law behaviour, which implies that the microcrack system may evolve to a critical state.     

人格判断的准确性:特质特性的作用

特质特性是影响人格判断准确性的重要调节变量。已有的研究表明,可观察性高的特质容易判断,判断的准确性和一致性也更高;特质的可评估性干扰了自我知觉的准确性,与中性特质相比,可评估性特质的自我—他人一致性更低;与清晰特质相比,模糊特质的自我—同伴判断间的一致性更低,且随特质模糊性的增加而递减。不仅如此,特质特性经常与其他因素如熟悉度交互作用于人格判断的准确性,在考查特质特性的作用时,必须提高研究的生态效度,将该变量与特性匹配、特质分类、个体差异及文化差异等因素综合起来考虑。     

伤害回避的脑机制及其生物基础

伤害回避是指个体对厌恶刺激信号做出强烈的反应,并学会被动地回避惩罚的一种倾向,这一倾向使得个体反复思考未来的结局,并谨慎小心地对待不确定情景中的事件,进而更有可能诱发情感障碍。伤害回避涉及的神经网络包括三个子网络,即额顶叶-前扣带皮层的连接、皮层-杏仁核的连接和白质通道的结构性连接,这三个子网络分别与羞怯感-易疲劳性、预期担心以及不确定环境中的害怕情绪有关。而其生物基础则包括单一基因多态性和基因多态间的交互作用。今后的研究应该集中在深化伤害回避神经网络与生物基础间的联合机制、研究三种及以上基因多态间的交互作用、考察其他因素对基因效应的调节作用、注重伤害回避四种亚型相关神经网络之间的连接、探讨5-HT4等其他几种5-羟色胺受体多态性与伤害回避的关系以及分析伤害回避内部机制在抗抑郁治疗中的作用等方面。     

智慧:结构、类型、测量及与相关变量的关系

智慧是个体在其智力与知识的基础上,经由经验与练习习得的一种德才兼备的综合心理素质,包括聪明才智与良好品德两大成份.智慧可分为常规智慧与应变智慧、群体智慧与组织智慧、个人智慧与一般智慧、德慧与物慧等,可用三维智慧量表、自我评估智慧量表以及智慧发展量表等进行测量,并与年龄、性别、文化、教育、人格、思维方式、智力等存在重要关联.今后应该深入探究智慧的概念与结构,拓展其研究方法、测量工具与教育策略以及开展中国化研究.     

当局者迷,旁观者清?自我-他人决策的理性差异及其机制

生活充满抉择,由于知识经验的局限,人们常需寻求他人建议,抑或直接请他人代己决策.诸多研究探讨了自我决策、向他人建议,以及代他人决策之间的差异.探究这种差异的动因之一在于考察何种条件下的决策更优或更“理性”.以往研究表明,自我决策或他人决策(向他人建议或代他人决策)均有可能更易违背理性决策原则,隐含着他人决策优于自我决策的“当局者迷,旁观者清”这一传统智慧有一定的边界条件.研究者一般从认知(建构水平理论)、情绪(类型和卷入度),以及动机(调节聚焦理论)三种视角对自我-他人决策差异进行解释.本文作者提出基于理由的决策(reason-based account)假设来解释自我-他人决策在理性程度上的差异.未来研究可从决策过程及脑机制上深入考察自我-他人决策差异及其机制.     

个人幸福指数-中小学生版(PWI-SC)在中国的适用性——兼与澳洲中学生比较

探讨个人幸福指数-中小学生版(PWI-SC)在中国的适用性以及中澳两国中学生个人幸福指数的跨文化差异。采用PWI-SC施测522名中国中学生、185名澳洲中学生,进行区分度、信度和效度检验,发现该问卷可运用于中国中学生个人幸福指数的调查,个别项目需稍加修改。比较中澳中学生的施测结果,中国中学生的个人幸福指数低于澳洲中学生,中国中学生得分为47-70,澳洲中学生得分为51-72;中国中学生除在个人已有成就项目上得分高于澳洲中学生外,其他方面均较低;中澳两国初中生的个人幸福指数均显著高于高中生,两国初高中生个人幸福指数的差异体现在不同方面;中澳两国中学生个人幸福指数的年龄差异均显著,进一步事后分析发现,两国中学生个人幸福指数的基本趋势均为随年龄增长,个人幸福指数降低,中国15岁中学生的个人幸福指数较高。PWI-SC基本适用于中国中学生;中学生随年龄增长,个人幸福指数降低;中国中学生的个人幸福指数低于澳洲中学生。     

Perceiving and Interacting Affordances: A New Model of Human–Affordance Interactions

This article introduces a new affordance framework for humans and human design. Based on previous important concepts in product design–affordance, signifier, and product semantics, the authors propose three new concepts to illustrate how people perceive affordance. According to the model, perceptual probability of affordance is the probability that the public can perceive a certain affordance; perceptual threshold of affordance is the threshold at which affordance can be perceived by a person and changed by perceptual information; and situations, in which interactions between affordances and people exist, are crucial influences on human–affordance interactions. An illustration of the model and suggestions for further research are provided.