Mechanically driven alloying forces in the fabrication of a Cr–Zr nanocomposite

A highly supersaturated nanocrystalline Cr–25?wt% Zr alloy has been prepared by mechanical alloying of elemental crystalline powders. High-purity powders of Cr and Zr were milled for up to 20?h. The development of the microstructure was investigated by X-ray diffraction (XRD) and scanning electron microscopy. XRD patterns confirmed complete alloying of the Zr and Cr. The contribution of grain boundaries, the chemical potential of a solute atom induced by dislocations, and the elastic strain energy arising from the different sizes of Cr and Zr atoms have been calculated. The alloy formation is discussed with respect to the thermodynamic conditions of the material. The role of internal strains and stored enthalpies by dislocations on solute atoms is the major mechanical driving force for alloying and this is critically assessed in this article.     

两例先天性无痛症患者的心理生理特点研究 Ⅱ.对致痛性强刺激的知觉和反应

本工作对两例先天性无痛症患者对于致痛性强刺激的知觉和反应进行了研究(例1女,10岁,例2男,13岁)。对照组为20例正常儿童,性别和年龄均与患儿相匹配。 结果:1),生活中痛:两例患儿均无(包括痛感觉和痛反应)。2)实验性痛:①痛感觉:两例患儿均无;②“痛”反应:例1有“痛”反应(脉搏和呼吸的变化以及行为反应明显,大致与正常儿童相似)。例2无“痛”反应(脉搏和呼吸的变化轻微,无行为反应,与正常儿童不同)。 由结果看来,先天性无痛症患者似乎可分为两种类型:不完全型(如同例1)和完全型(如同例2)。存在有“痛”反应而无痛感觉的无痛症患者。 本工作结果从另一侧面为痛的两成分学说提供了依据。     

内隐和外显记忆测验中的具体性效应

通过三个实验考察词语的具体性对概念内隐和外显记忆测验成绩的影响,检验加工说对概念变量的预测,并对双重编码理论进行评析。实验一通过操纵词频变量发现,在低频词的再认中有具体性效应,但偏好测验中没有产生具体性效应。实验二使用低频词发现,词语联想和词语线索回忆中都有具体性效应。实验三通过操纵编码任务,在偏好测验中又获得了具体性效应。总体的实验结果既不完全符合加工说,也给双重编码理论带来了问题。     

单一被试实验与元分析技术

单一被试实验是特殊儿童心理与教育研究中的一种常用方法,但其外部效度往往受到质疑。运用元分析技术,能对大量单一被试实验研究结果进行定量综述,既可综合评价各研究的总效应,也能探讨、揭示出各类研究特征与相应研究结果的关系,这无疑为单一被试实验信度与效度的检验提供了更多的信息。本文结合国外一个较新的研究实例,对元分析技术的基本原理及分析步骤作简要介绍,并对单一被试实验与元分析技术的结合应用问题提出几点看法与建议。     

我听到的鬼叫声

小时候,母亲白天要干很多活儿,夜里才有时间纺棉花。为了抵御瞌睡虫的攻击,她就经常让我陪坐在她的纺车旁,听她讲故事。     

From Spontaneous to Planned Urban Development and Quality of Life: the Case of Ho Chi Minh City

This paper studies the quality of life (QOL) that residents perceive in typical urban patterns in Ho Chi Minh City. Its major focus is to examine the improvement in the QOL through public intervention into the urban development process. There are four findings. First, moderate government intervention to correct market failures in areas where spontaneous urban development has occurred generates similar levels of satisfaction to areas with planned development. Second, urban planning is important as housing values and subjective satisfactions in planned areas are higher than those in spontaneous development areas. Third, redevelopment negatively affects the QOL in areas undergoing redevelopment. Finally, the contrast between the housing value and the subjective life satisfaction in spontaneous development areas undergoing redevelopment shows the problem of relying on the revealed preference assumption in traditional economics and the need for having alternative approaches.     

Developmental changes associated with cross-language similarity in bilingual children

The main goal of the present study was to investigate how the degree of orthographic overlap between translation equivalents influences bilingual word recognition processes at different stages of reading development. Spanish–Basque bilingual children with ages ranging from 8 to 15 years were tested in an explicit translation recognition task with a large set of items. Critically, the degree of cross-language similarity (i.e. the cognate status) between the references and the correct targets was manipulated along a continuum in order to investigate how the reliance on cross-language orthographic overlap varies as a function of reading experience. Results showed that younger children were significantly more sensitive to the cognate status of words than older children while recognising translation equivalents, and that this difference did not depend on the speed of response of the participants. These results demonstrate that the influence of cross-language similarity progressively diminishes as a function of increased exposure to print together with the maturation of the mechanisms responsible for language interference suppression, as suggested by developmental models of bilingual lexical access.     

Perfectionism mediated the relationship between brain structure variation and negative emotion in a nonclinical sample

In maladaptive respects, perfectionism reflects an individual’s concern over making mistakes and doubting the quality of his or her own actions excessively, which would affect one’s emotion. However, little is known about the neural mechanisms associated with the perfectionism and negative affect. In this study, voxel-based morphometry was performed to identify the brain regions underlying individual differences in perfectionism, which was measured by the Chinese Frost Multidimensional Perfectionism Scale (CFMPS), in a large sample of nonclinical young adults. Our results showed that the two subdimensions of the perfectionism, concern over mistakes (CM) and doubts about actions (DA), were both positively correlated with the self-reported anxiety and depression as well as the gray matter volume (GMV) in the anterior cingulate cortex (ACC), a pivotal brain region in cognitive control, affective state, and regulation. Moreover, CM, DA, and organization scores were respectively correlated with distributed brain regions involved in multiple cognitive and emotion processes. Our results furthermore revealed that the score of DA acted a mediational mechanism underlying the relationship between the GMV of ACC and self-rating negative affect (anxiety and depression). Taken together, these results might suggest the neuroanatomical basis of perfectionism and the association among the perfectionism, negative emotion, and brain architecture. This study emphasized that perfectionism could play a crucial role in the arousal of negative affect.     

When an Object Appears Unexpectedly: Object Circumvention in Adults

Obstacles often appear unexpectedly in our pathway and these require us to make immediate adjustments. Despite how regularly we encounter such situations only few studies have considered how we adjust to unexpected obstacles in the pathway that require us to walk around them. The authors considered how adults adjust to the possibility of an obstacle appearing and then also how foot placement is adjusted to circumvent an obstacle. Fifteen healthy adults walked down an 11-m walkway, initially they were told this was a clear pathway and nothing in the environment would change (no gate), they then performed a series of trials in which a gate may (gate close) or may not (gate open) partially obstruct their pathway. The authors found that mediolateral trunk velocity and acceleration was significantly increased when there was the possibility of an obstacle but before the obstacle appeared. This demonstrates an adaptive walking strategy that seems to enable healthy young adults to successfully circumvent obstacles. The authors also categorized foot placement adjustments and found that adults favored making shorter and wider steps away from the obstacle. They suggest this combination of adjustments allows participants to maintain stability while successfully circumventing the obstacle.