三维拓扑绝缘体超材料光电效应仿真

提出了一种基于三维拓扑绝缘体Bi_(1.5)Sb_(0.5)Te_(1.8)Se_(1.2)的周期性方环阵列超材料结构。仿真结果表明超材料结构的表面等离子体共振强度随阵列周期和方环内环尺寸的减小而增大,其中,当周期为300 nm或尺寸为25 nm时,可以限制80%的电磁波在表面态上。此外,通过仿真正、斜圆偏振光入射下超材料和非超材料结构的表面电场随偏振态的变化关系,得到了两种结构正、斜入射下的圆二色性;结果表明,超材料结构圆二色性数值为0.92,远大于非超材料结构,并且该超材料结构的圆偏振分量在总偏振光电流分量的占比有显著提升,这是因为有更多的自旋电子被圆偏振光从拓扑表面态激发到体导带上。

Shifting towards a Mediterranean Diet in the US： How Far Do We Have to Go, What Are the Potential Health Benefits and Can We Get There？

In the public dialogue surrounding the development of the 2015 dietary guidelines for Americans, public health and environmental advocates converged around a simple theme of shifting towards a more plant-forward Mediterranean-style diet. A robust body of literature documenting the health benefits of this eating pattern provides compelling reasons to change our dietary habits in ways that also benefit our environment, but we also need to have the right foods available and affordable to support this modest shift. This commentary discusses the gaps in current US dietary intakes compared to recommendations for meat and protein versus plant-based foods and the potential health benefits of shifting towards a more plant-based diet, focusing on the complex role of Mediterranean crops, such as tree nuts and olive oils, needed to support this shift.

温雅静敛闲处之 坐看平湖生烟雨

想象着，安静的湖面上下起绵绵细雨，烟雾朦胧袅袅升起，远处的青山、近处的烟雨、优雅静怡的天青色，如此诗意、静好的场景!有段时间，我们可能都曾被这样的一句话刷屏：生活不止眼前的苟且，还有诗和远方。在如此纷繁复杂的世界里，有多少人能够不当一只“蜗牛”？但即便如此，我们还是不能失去对诗意生活的向往。