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物理学院“博约学术沙龙”系列报告(第148期)

发布日期:2017年12月16日

时  间:   2017年12月18日(星期一)下午 14:30

地  点:   中心教学楼610

题  目:评价Quest算法在图像模糊度阈值视觉实验中的表现

报告人: 袁悦                指导老师:刘贵斌

摘要:In this paper, Quest algorithms were employed to research the blur discrimination thresholds of human eyes on digital images. The threshold experiment was carried out with 2 images from McGill database that were blurred into 131 images with specific blurriness using a Gaussian filter. 15 observers with normal vision participated in the study. To verify the reliability of the Quest method and to make a contrast, each observer conducted threshold experiments in two different ways: one, using the general bi-directional approach (blurriness continuously changing), and two, using the Quest method (blurriness changes according to previous judgment). Data were collected on each observer and a vertical comparison of the results of the two methods was made. In 60 experiments, 52% showed that the results from the Quest method are approximately consistent with those from bi-directional approach method. Horizontal comparisons between the results of 15 observers showed that the blurriness threshold of human eyes is highly correlated to subjects, but beyond that, it is varied substantially with image contents, especially image texture. Quest method shows its efficiency and potential in dealing with accurate sensation problems in the visual threshold experiments.

题  目:外场调制下二维半导体 GeSe 电子性质研究

报告人:张宇                指导老师:石丽洁

摘要:首先通过外加电场调控二维 GeSe 的带隙,在外加垂直电场的作用下,二维 GeSe 的带隙会根据场强大小发生线性的变化,并且带隙的位置不会发生改变, GeSe 带隙最终将被关闭,呈现出半金属(semi-metal)的性质。之后,我们通过外加应力调控二维GeSe 的带隙,使得二维 GeSe 的带隙发生了从间接带隙到直接带隙的转变。最后我们将电场与应力结合对材料的带隙进行调节,先施加应力将二维GeSe 从间接带隙转变成直接带隙,然后再施加垂直电场,这样可以取长补短,使得这个直接带隙在更大的范围内可调。

 

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