https://www.nature.com/articles/s41565-018-0259-z Nature Nanotechnology, Anisotropic polarization-induced conductance at a ferroelectric–insulator interface, Nature Nanotechnologyvolume 13, pages1132–1136 (2018) 10.1038/s41565-018-0259-z
m*3
4 楼
自己顶起来。请求各位有经验的人建议。多谢。
t*1
5 楼
If they want to apply visa for sightseeing in US not staying with you, your invitation letter is not needed. Just say they want to come to US and have fun is enough.