Structure of Al–Co–Ni pentagonal quasicrystal studied by HAADF-STEM and ab initio calculations

Using a combination of atomic-resolution high-angle annular dark-field (HAADF) Z-contrast imaging and ab initio calculations, atomic models of clusters 2 nm in diameter and 0.8 nm in height are proposed for the Al–Co–Ni pentagonal quasicrystal. This quasicrystal has 5-fold symmetry (the so-called 5f state) without superstructures, and is one of numerous modifications of the Al–Co–Ni decagonal quasicrystal. HAADF results reveal that the two-dimensional quasi-periodic lattice contains mainly Penrose pentagonal tiling. The centres within the decorated pentagonal tiles, i.e. the so-called pentagonal super-clusters, show structural characteristics having both a satellite-orbit shape and a pentagon-symmetry shape. The proposed atomic models, based directly on the HAADF images, are subjected to ab initio total energy calculations. After relaxation, the calculations demonstrate that the models with 5-fold symmetry are energetically more favourable than those with 10-fold symmetry.     

Blue or red? The effects of colour on the emotions of Chinese people

Two experiments were performed to examine the effects of red and blue on the emotional pleasure of Chinese people. Experiment 1 explored the effects of the ‘physical’ colours red and blue on emotion, and the results showed that red induced positive and negative emotion, while blue only induced positive emotion. Experiment 2 further explored the effects of the ‘verbal’ colours red and blue on emotion, and the results showed that red induced only positive emotion, while blue induced neither positive nor negative emotion. The findings indicate that the influence of colour on emotion is rooted in both natural and social associations. For Chinese, the associations between blue and positive emotion, and red and negative emotion, were natural associations; however, the associations between red and positive emotion were social associations. Moreover, physical colour and verbal colour stimuli induced emotions by activating different mechanisms: physical colour induced emotions via both natural and social associations, whereas verbal colour induced emotions via social associations.