Phase stability of Al3Nb as a function of nickel additions

Abstract

Phase stability of the intermetallic compound Al₃Nb is investigated as a function of nickel additions by band structure calculations based on an extended Hueckel tight-binding method. With this method, the electronic structure and total energies of the Al_6-n -Ni _n Nb₂ compounds (where n is an integer from 0 to 6) are calculated for both D0₂₂ and L1₂ structures under the assumption that nickel substitutes for aluminium. The electronic total energies obtained from integration of the energy states of all electrons considered have shown that the D0₂₂ structure is stable in the binary Al₃Nb compound as compared with the L1₂ structure; conversely, the L1₂ structure is stable for compounds with n values greater than 1. These calculations are in good agreement with X-ray diffraction results reported by Schubert and co-workers. Differences in the electronic total energy per atom between D0₂₂ and L1₂ are - 0·79 eV and 0·56 eV for n equal to 0 and 2, respectively.     

Unpacking Cultural Variations in Peak-Experiences: Cross-Cultural Comparisons of Early Childhood Recollection Between Hong Kong and Brazil

In this cross-cultural study, 115 Hong Kong Chinese and 117 Brazilian college students described a childhood peak-experience (occurring before the age of 14) and provided a self-rating on its enduring impact. Among various categories of peak-experiences, both Hong Kong Chinese and Brazilians reported interpersonal joy most frequently; the second most frequently reported category was external achievement for the Hong Kong sample and developmental landmark for the Brazilian sample. Compared with Brazilians’ narratives, those of Hong Kong Chinese were more social-focused, involving greater number of other people, but less specific. These characteristics of autobiographical memory, i.e., memory focus (self vs. social), memory specificity (specific vs. general), and the number of other people involved, significantly mediated the relation between culture and interpersonal joy. The present findings have extended research on peak-experiences to cross-cultural contexts and incorporated measures of autobiographical memory to unpack cultural variations in these two collectivist societies.     

成人期人际性问题解决的策略取向研究

采用开放式问卷,考察252名25至75岁的成人解决人际性问题的策略取向。结果表明：总体上中国成人偏重于二级控制取向;成人前期个体较其他年龄段成人表现出更多的一级控制取向;情境因素对成人的策略取向有较大影响,并且这种影响对不同年龄段成人所产生的效应存在明显差异。     

Systematic angular biases in the representation of visual space

Representing spatial information is one of our most foundational abilities. Yet in the present work we find that even the simplest possible spatial tasks reveal surprising, systematic misrepresentations of space—such as biases wherein objects are perceived and remembered as being nearer to the centers of their surrounding quadrants. We employed both a placement task (in which observers see two differently sized shapes, one of which has a dot in it, and then must place a second dot in the other shape so that their relative locations are equated) and a matching task (in which observers see two dots, each inside a separate shape, and must simply report whether their relative locations are matched). Some of the resulting biases were shape specific. For example, when dots appeared in a triangle during the placement task, the dots placed by observers were biased away from certain parts of the symmetry axes. But other systematic biases were not shape specific, and seemed instead to reflect differences in the grain of resolution for different regions of space. For example, with both a circle and even a shapeless configuration (with only a central landmark) in the matching task, observers were better at discriminating angular differences (when a dot changed positions around the circle, as opposed to inward/outward changes) in cardinal versus oblique sectors. These data reveal a powerful angular spatial bias, and highlight how the resolution of spatial representation differs for different regions and dimensions of space itself.

     

Self-control and frequency of model presentation: Effects on learning a ballet passé relevé

The purpose of this experiment was to examine the combined effects of self-control and frequency of model presentation on learning a complex motor skill, i.e., ballet passé relevé. Before practice started self-control participants were asked to choose two viewings or six viewings (before practice and then every five trials) and the externally controlled groups were yoked to their self-control counterparts. All participants completed 15 acquisition trials followed by 5 trials for the immediate and 5 trials for the delayed retention tests 48 hours later. Dependent variables included cognitive representation scores, physical reproduction rankings, and balance time. Statistical analyses indicated that under limited physical practice conditions self-control and higher frequency of model presentation facilitated the development of cognitive representation and did not produce further benefits in movement reproductions and balance time. The results were discussed with respect to the social cognitive theory.     

形上之维的更生与语言的可能承诺——一种回应解构而重返形而上者的尝试

本文对“解构”思潮颠覆“形而上者”所可能达到的限度作了审慎辨析,并就此探讨了形上之维更生的价值依据及新形态的形而上学得以构建的语言契机。     

从理性到信仰:西方自由观的转向——对奥古斯丁信仰自由观的一种解读

在古希腊理性精神与基督教信仰文化交汇的大背景下,奥古斯丁扬弃柏拉图和亚里士多德等思想家的理性自由观,提出了以基督教信仰为基础的信仰自由观。这种自由观展示了信仰、自由意志和理性三者之间富有张力的依存关系,实现了西方自由观的转向,对后来的西方哲学与文化发生了深远影响。这种自由观在德国古典哲学尤其是黑格尔的哲学中得到复兴,但由于从根本上并没有克服自由与决定论之间的困境,现实的人的自由、理性与信仰在黑格尔哲学中都被消解了。即便如此,在当代一些重要的思想家那里,奥古斯丁确立的思维范式依然具有实质性影响。     

明代伏牛山佛教派系考

历史上对伏牛山地区的佛教记载较散,资料较详的是在明代。当时来山修行的僧人很多,但是到现在为止还没有人对伏牛山的佛教进行过研究,笔者根据掌握的禅宗史料提出这时伏牛山佛教已经有了明显的禅宗派系特征,在这里传教修行的僧人,主要是元代禅宗断桥伦一支的浙江天目山高峰原妙及其弟子中峰明本一系,其中受四川禅宗无际明悟禅师一派的影响很大,早期来山的僧人大多数都是无际明悟的弟子与后人,可以说成立了无际伏牛山禅派一系。     

一致的先前知识对类别学习影响机制探讨

探讨一致的先前知识对类别学习的影响,包括2个实验。被试是112名大学生,分别探讨不同实验任务和不同项目呈现时间引发的机械特征在类别学习中的重要程度和加工程度不同的情况下先前知识对类别学习的影响。结果表明:(1)在实验任务为项目类别归属判断任务时,机械特征重要程度低,主题特征与机械特征在学习上存在竞争关系;在实验任务为项目类别归属及记忆任务时,机械特征重要程度高,主题特征与机械特征在学习上存在促进关系。(2)在限制步速呈现项目时,机械特征加工程度低,主题特征与机械特征在学习上存在竞争关系;而在自定步速呈现项目时,机械特征加工程度高,主题特征与机械特征在学习上不存在竞争关系。     

时间性前瞻记忆研究取向与焦点问题

时间性前瞻记忆是指形成和保持一个意向,在一段时间后的某个特定的时间(目标时间)执行.文章通过对时间性前瞻记忆的研究取向、方法和现有理论模型的回顾,总结出该领域中的三个争论焦点.