Moore＇s law is approaching its physical limit. Tunneling field-effect transistors （TFETs） based on two-dimensional （2D） materials provide a possible scheme to extend Moore＇s law down to the sub-10-nm region owin...Moore＇s law is approaching its physical limit. Tunneling field-effect transistors （TFETs） based on two-dimensional （2D） materials provide a possible scheme to extend Moore＇s law down to the sub-10-nm region owing to the electrostatic integrity and absence of dangling bonds in 2D materials. We report an ab initio quantum transport study on the device performance of monolayer （ML） black phosphorene （BP） TFETs in the sub-10-nm scale （6-10 nm）. Under the optimal schemes, the ML BP TFETs show excellent device performance along the armchair transport direction. The on-state current, delay time, and power dissipation of the optimal sub-10-nm ML BP TFETs significantly surpass the latest International Technology Roadmap for Semiconductors （ITRS） requirements for high- performance devices. The subthreshold swings are 56-100 mV/dec, which are much lower than those of their Schottky barrier and metal oxide semiconductor field-effect transistor counterparts.展开更多
Groundwater level change stands a momentous role in affecting the geotechnical construction stability and safety of underground structures.Global warming and active underground construction cause conspicuous changes i...Groundwater level change stands a momentous role in affecting the geotechnical construction stability and safety of underground structures.Global warming and active underground construction cause conspicuous changes in the groundwater level,which further leaves an impact on the underground structures’serviceability.To reveal the interaction between underground structure and soil under groundwater level change in the sand layer,model tests of circular transportation tunnel and rectangular utility tunnel were carried out.With the self-designed experimental equipment and innovative experimental methods,the changes in tunnel stress,bending moment,buoyancy,and vertical displacement of the rise and drawdown of the groundwater level in the sand layer were studied.The results revealed the developments of concentrated structural forces during the rising and falling process of the groundwater water level,indi-cating critical locations that should be strengthened.Meanwhile,both tunnels showed the same movement trend:settling first,floating afterwards and settling at last.And it is concluded that no reduction is required when calculating buoyancy in sands using measured pore pressure.Conclusions can provide a notable reference for future related research and engineering designs.展开更多
基金This work was supported by the Scientific Research Start-up Funding of North China University of Technology, the Youth Innovation Foundation of North China University of Technology （No.1743026）, the National Natural Science Foundation of China （Nos.11674005 and 11704008）, National Materials Genome Project （No. 2016YFB0700601）, and the National Basic Research Program of China （No. 2013CB932604）.
文摘Moore＇s law is approaching its physical limit. Tunneling field-effect transistors （TFETs） based on two-dimensional （2D） materials provide a possible scheme to extend Moore＇s law down to the sub-10-nm region owing to the electrostatic integrity and absence of dangling bonds in 2D materials. We report an ab initio quantum transport study on the device performance of monolayer （ML） black phosphorene （BP） TFETs in the sub-10-nm scale （6-10 nm）. Under the optimal schemes, the ML BP TFETs show excellent device performance along the armchair transport direction. The on-state current, delay time, and power dissipation of the optimal sub-10-nm ML BP TFETs significantly surpass the latest International Technology Roadmap for Semiconductors （ITRS） requirements for high- performance devices. The subthreshold swings are 56-100 mV/dec, which are much lower than those of their Schottky barrier and metal oxide semiconductor field-effect transistor counterparts.
基金the financial support from National Major Scientific Instruments Development Project of China(Grant no.5202780029)High-end Foreign Expert Introduction program(No.DL2021165001L)Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJCXZD2020002).
文摘Groundwater level change stands a momentous role in affecting the geotechnical construction stability and safety of underground structures.Global warming and active underground construction cause conspicuous changes in the groundwater level,which further leaves an impact on the underground structures’serviceability.To reveal the interaction between underground structure and soil under groundwater level change in the sand layer,model tests of circular transportation tunnel and rectangular utility tunnel were carried out.With the self-designed experimental equipment and innovative experimental methods,the changes in tunnel stress,bending moment,buoyancy,and vertical displacement of the rise and drawdown of the groundwater level in the sand layer were studied.The results revealed the developments of concentrated structural forces during the rising and falling process of the groundwater water level,indi-cating critical locations that should be strengthened.Meanwhile,both tunnels showed the same movement trend:settling first,floating afterwards and settling at last.And it is concluded that no reduction is required when calculating buoyancy in sands using measured pore pressure.Conclusions can provide a notable reference for future related research and engineering designs.
