Atomic geometry and energetics of carbon nanotube necking

Molecular mechanics simulations were performed to probe the incipient plastic deformation in carbon nanotubes (CNTs), which involves nucleation of Stone–Wales (SW) defects and spiral glide of 5/7 dislocation dipoles that lead to quantized necking through a stepwise reduction in tube diameter. Quantification of the strain-dependent energetics of dislocation glide reveals that such dislocation motions are energetically favoured at high tensile strain. Pre-existing dislocations critically affect subsequent nucleation and separation of SW defects, as manifested by the competing deformation modes of symmetric versus asymmetric necking. The results provide a quantitative basis for the dislocation dynamics simulations of superplastically deformed CNTs.     

Two different types of shear-deformation behaviour in Au–Cu multilayers

Localised shear deformation of a material is usually identified as a particular feature of deformation inhomogeneity. Here, we show two different types of shear deformation-behaviour that occurred in Au–Cu multilayers subjected to microindentation load, namely, a cooperative-layer-buckling-induced shear banding in a nanoscale multilayer and a direct localised shearing across a layer interface along a shear plane in a submicron-scale multilayer. Theoretical analysis indicates that the formation of the two different types of shear deformation in the multilayers depends on a competition between the dislocation-pile-up-induced stress concentration at the layer interface and the barrier strength of the layer interface for glissile dislocation transmission.     

Amorphization of TiNi induced by high-pressure torsion

Using high-resolution electron microscopy, we investigated the initial stages of high-pressure-torsion-induced crystalline-to-amorphous transformation of TiNi. It is found that the deformation-induced amorphization initiated from dislocation core regions in the interior of grains and from grain boundaries. It is believed that both the energy stored in the dislocations and the energy stored in the grain boundaries contribute significantly to driving the crystalline-to-amorphous transformation.     

Study of γ/γ′ interfacial width in a nickel-based superalloy by scanning transmission electron microscopy

The γ/γ′ interfaces are thought to play an important role in determining the mechanical properties in single-crystal nickel-based superalloys. In this article, interfacial width in DD6, one second-generation single-crystal superalloy containing 2 wt% Re, has been studied by means of scanning transmission electron microscopy. From an atomic resolution high angle annular dark field image, both compositional interfaces and order–disorder interfaces are studied, and it is first found that the interfacial width of chemical composition is same with that between the ordered and disordered phases.     

Unconsciously learning task-irrelevant perceptual sequences

We demonstrated unconscious learning of task-irrelevant perceptual regularities in a Serial Reaction Time (SRT) task in both visual and auditory domains. Participants were required to respond to different letters (‘F’ or ‘J’, experiment 1) or syllables (‘can’ or ‘you’, experiment 2) which occurred in random order. Unbeknownst to participants, the color (red, green, blue or yellow) of the two letters or the tone (1–4) of the syllables varied according to certain rules. Reaction times indicated that people indeed learnt both the color and tonal regularities indicating that task-irrelevant sequence structure can be learned perceptually. In a subsequent prediction test of knowledge of the color or tonal cues using subjective measures, we showed that people could acquire task irrelevant knowledge unconsciously.     

Factors Associated With Adverse Mental Health Outcomes in Locally Recruited Aid Workers Assisting Iraqi Refugees in Jordan

Nongovernmental organizations (NGOs) serve Iraqis living in Jordan as “guests.” In 2008, 258 Jordanian humanitarian staff and Iraqi volunteers working for NGOs completed a needs assessment survey. Work characteristics, stressors, and support variables were evaluated regarding their influence on depression, anxiety, post-traumatic stress disorder (PTSD), and burnout through multivariate logistic regressions. There was a significant difference in depression, anxiety, and burnout across nationality. Traumatic exposure increased the risk for anxiety, depression, and PTSD. Working longer in the humanitarian sector was associated with less risk of anxiety and depression, and lower social support was a risk for anxiety. Managers were at higher risk for burnout, and low team cohesion was a risk for burnout. Implications for aid organizations are discussed.     

“如果P,那么Q,……?”─—儿童充分条件假言演绎推理能力发展初探

以日常生活事件为内容的三套测验题探查了9－15岁儿童充分条件假言推理能力的发展。研究发现被试有关能力的发展可以区分出三种不同水平;儿童对充分条件假言推理规则的掌握没有固定的难易顺序,这取决于课题任务的性质和主体思维发展水平。研究还探查了发展的个体内部差异和个体之间的差异以及影响差异的各种内外因素。     

人格相似性与关系质量的关系：单向视角

温州两所大学的199个大学生在人际形容词量表上对自己的人际特质进行评定,并对自己选定的一个关系对象进行评定,感知与选定对象的人格相似性,同时评定与该对象的关系质量。根据自我报告和评定对象计算出假定相似性。对关系质量的分层回归分析得到人际特质两个维度的交互效应均为正,即表现出假定相似相吸的效应趋势,亲和性维度显著;相关显示假定的相似性和感知的相似性与关系质量均呈中等程度相关;路径分析表明感知的相似性中介假定相似性与关系质量的关系。     

任法融会长参加香港啬色园黄大仙祠90周年纪庆系列活动

1月8日至11日,中国道教协会会长任法融一行应邀赴港参加香港啬色园黄大仙祠90周年纪庆系列活动。随同任会长访港的有中国道教协会副秘书长李兆彩、北京白云观管委会主任李信军等9人。