Ultrathin Perfect Absorbers for Normal Incident Waves Using Dirac Cone Metasurfaces With Critical External Coupling

2020 ◽  
Vol 30 (4) ◽  
pp. 383-386
Author(s):  
Yuto Kato ◽  
Subaru Morita ◽  
Hidehisa Shiomi ◽  
Atsushi Sanada
2020 ◽  
Vol 16 (4) ◽  
pp. 595-607 ◽  
Author(s):  
Mu Wen Chuan ◽  
Kien Liong Wong ◽  
Afiq Hamzah ◽  
Shahrizal Rusli ◽  
Nurul Ezaila Alias ◽  
...  

Catalysed by the success of mechanical exfoliated free-standing graphene, two dimensional (2D) semiconductor materials are successively an active area of research. Silicene is a monolayer of silicon (Si) atoms with a low-buckled honeycomb lattice possessing a Dirac cone and massless fermions in the band structure. Another advantage of silicene is its compatibility with the Silicon wafer fabrication technology. To effectively apply this 2D material in the semiconductor industry, it is important to carry out theoretical studies before proceeding to the next step. In this paper, an overview of silicene and silicene nanoribbons (SiNRs) is described. After that, the theoretical studies to engineer the bandgap of silicene are reviewed. Recent theoretical advancement on the applications of silicene for various field-effect transistor (FET) structures is also discussed. Theoretical studies of silicene have shown promising results for their application as FETs and the efforts to study the performance of bandgap-engineered silicene FET should continue to improve the device performance.


2021 ◽  
Vol 9 (6) ◽  
pp. 600
Author(s):  
Hyun Dong Kim ◽  
Shin-ichi Aoki

When erosion occurs, sand beaches cannot maintain sufficient sand width, foreshore slopes become steeper due to frequent erosion effects, and beaches are trapped in a vicious cycle of vulnerability due to incident waves. Accordingly, beach nourishment can be used as a countermeasure to simultaneously minimize environmental impacts. However, beach nourishment is not a permanent solution and requires periodic renourishment after several years. To address this problem, minimizing the period of renourishment is an economical alternative. In the present study, using the Tuvaluan coast with its cross-sectional gravel nourishment site, four different test cases were selected for the hydraulic model experiment aimed at discovering an effective nourishment strategy to determine effective alternative methods. Numerical simulations were performed to reproduce gravel nourishment; however, none of these models simultaneously simulated the sediment transport of gravel and sand. Thus, an artificial neural network, a deep learning model, was developed using hydraulic model experiments as training datasets to analyze the possibility of simultaneously accomplishing the sediment transport of sand and gravel and supplement the shortcomings of the numerical models.


2021 ◽  
Vol 9 (12) ◽  
pp. 4316-4321
Author(s):  
L.-B. Meng ◽  
S. Ni ◽  
Z. M. Zhang ◽  
S. K. He ◽  
W. M. Zhou

Density functional theory calculation predicts a novel ordered boron phosphorus codoped graphene realizing a widely tunable Dirac-cone gap.


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