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171.
It is interesting to investigate the formation of He bubbles in amorphous alloys because point defects do not exist in amorphous materials. In the present study, the microstructural evolution of amorphous Fe79B16Si5 alloy, either irradiated with 5?keV He+ ions or implanted with 150?eV He+ ions without causing displacement damage, and then annealed at a high temperature, was investigated using transmission electron microscopy (TEM). Vacancy-type defects were formed in the amorphous alloy after irradiation with 5?keV He+ ions, and He bubbles formed during annealing the irradiated samples at high temperature. On the other hand, for samples implanted with 150?eV He+ ions, although He atoms are also trapped in the free volume, no He bubbles were observed during annealing the samples even up to 873?K. In conclusion, the formation of He bubbles is related to the formation and migration of vacancy-type defects even in amorphous alloys.  相似文献   
172.
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.  相似文献   
173.
The current study tested 2 models of inhibition in 45 children with language impairment and 45 children with normally developing language; children were aged 7 to 12 years. Of interest was whether a model of inhibition as a mental-control process (i.e., executive function) or as a mental resource would more accurately reflect the relations among mental-attentional (M) capacity, inhibition, updating, shifting, and language competence. Children completed measures of M-capacity (in the verbal and nonverbal domains), inhibition, updating, shifting, and language. Path analyses showed the data provided a poor fit to the model of inhibition as a mental-control process but a good fit to the model of inhibition as a mental resource. Results are consistent with the theory of constructive operators and suggest inhibition is a mental resource rather than a mental-control process.  相似文献   
174.
This research examines the early emergence of source-monitoring abilities. Previous research has consistently demonstrated that children as young as 3 to 4 years of age do well on simple versions of action-based source-monitoring tasks. Research on even younger children, however, remains lacking. In this study we examined whether 2½-year-olds could accurately recall source on a simplified task. For the procedure, we used an action-based task in which children collaborate with an experimenter to build a model farm. During construction, the child and the experimenter took turns placing items on the farm. After construction, children were administered a source memory test in which they were asked to recall who had placed each item. To more closely examine factors that influence source accuracy in this young population, we included two conditions that varied in terms of contextual support. In the no-context-cues condition, in line with typical source-monitoring tasks, children were asked the source test question while items were presented individually and the farm was not in view. In the context-cues condition, the original spatial array of farm items was left intact to provide additional cues for children's source decisions. The main finding was that children in both conditions showed high levels of source accuracy at test indicating a surprisingly early age of emergence for this ability. Also, as predicted, children in the context-cues condition were the most accurate in attributing source.  相似文献   
175.
The notion of a mental time-line (i.e., past corresponds to left and future corresponds to right) supports the conceptual metaphor view assuming that abstract concepts like “time” are grounded in cognitively more accessible concepts like “space.” In five experiments, we further investigated the relationship between temporal and spatial representations and examined whether or not the spatial correspondents of time are unintentionally activated. We employed a priming paradigm, in which visual or auditory prime words (i.e., temporal adverbs such as yesterday, tomorrow) preceded a colored square. In all experiments, participants discriminated the color of this square by responding with the left or the right hand. Although the temporal reference of the priming adverb was task irrelevant in Experiment 1, visually presented primes facilitated responses to the square in correspondence with the direction of the mental time-line. This priming effect was absent in Experiments 2, 3, and 5, in which the primes were presented auditorily and the temporal reference of the words could be ignored. The effect, however, emerged when attention was oriented to the temporal content of the auditory prime words in Experiment 4. The results suggest that task demands differentially modulate the activation of the mental time-line within the visual and auditory modality and support a flexible association between conceptual codes.  相似文献   
176.
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。  相似文献   
177.
求职者简历作假行为是指求职者在简历投递过程中,为提升进入下一轮选拔几率,在简历中表现出虚假信念或信息的行为。研究通过访谈和问卷调查方法,探讨了求职者简历作假行为的结构,以及大学生求职群体简历作假行为的影响因素与特点。结果表明:(1)求职者的简历作假行为包含迎合招聘企业、篡改个人信息、粉饰关键词句和提升匹配程度四个因素。(2)马基雅维利主义倾向可以预测其简历作假行为。(3)大学生求职者的简历作假行为在其简历投递次数以及简历修改次数上存在差异。  相似文献   
178.
采取整群抽样的方法,对成都及重庆两地591名流动儿童和272名城市儿童进行问卷调查,考察流动儿童疏离感的特点及其与应对方式和学校态度的关系。结果发现:(1)流动儿童疏离感各维度显著高于城市儿童;流动初中生的疏离感显著高于流动小学生,且男生的疏离感显著高于女生;(2)流动儿童疏离感的三个维度之间存在显著差异,其中社会疏离感最高,其次是环境疏离感,人际疏离感最低;(3)流动儿童疏离感对学校喜欢有显著的负向影响,而对学校回避有显著的正向影响;应对方式在流动儿童疏离感对学校态度的影响中起着部分中介作用。  相似文献   
179.
偏离行为的研究在社会学和组织行为学领域都有较丰富的成果,然而其关注点主要集中于对社会或组织产生负面作用的消极偏离行为。近年来相关领域的学者越来越关注积极偏离行为(Positive Deviance, PD)的研究。该文综述了关于积极偏离行为的定义的各方观点,同时分析了积极偏离行为与相似构念的差异,并综述了积极偏离行为的测量方式,以及积极偏离行为的前因变量和结果变量。最后对积极偏离行为未来的研究方向进行了展望。  相似文献   
180.
Lewis的临时内在性问题出名地难以理解,也许是因为它质疑了某些我们认为理所当然的基本概念。本文通过简明地陈述问题和对若干可能解法的分析试图使之易于理解。此外,本文给出了一个产生Bradley倒退的简明易懂的方法。  相似文献   
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