Method of the Laboratory Wave Generation for Two Dimensional Hydraulic Model Experiment in the Coastal Engineering Fields: Case of Random Waves

The experiments in coastal engineering are very complex and a lot of components should be concerned. The experience has an important role in the successful execution. Hydraulic model experiments have been improved with the development of the wave generator and the advanced measuring apparatus. The hydraulic experiments have the advantage, that is, the stability of coastal structures and the hydraulic characteristics could be observed more intuitively rather than the numerical modelings. However, different experimental results can be drawn depending on the model scale, facilities, apparatus, and experimenters. In this study, two-dimensional hydraulic experiments were performed to suggest the guide of the test wave(random wave) generation, which is the most basic and important factor for the model test. The techniques for generating the random waves with frequency energy spectrum and the range for the incident wave height [(HS)M/(HS)T = 1~1.05] were suggested. The proposed guide for the test wave generation will contribute to enhancing the reliability of the experimental results in coastal engineering.

Terahertz interface physics: from terahertz wave propagation to terahertz wave generation

Terahertz (THz) interface physics as a new interdiscipline between THz technique and condensed matter physics has undergone rapid developments in recent years. Especially, the developments of advanced materials, such as graphene, transitional metal dichalcogenides, topological insulators, ferromagnetic metals, and metamaterials, have revolutionized the interface field and further promotes the development of THz functional devices based on interface physics. Moreover, playing at the interface with these advanced materials could unveil a wealth of fascinating physical effects such as charge transfer, proximity effect, inverse spin-Hall effect, and Rashba effect with THz technology by engineering the charge, spin, orbit, valley, and lattice degrees of freedom. In this review, we start from the discussion of the basic theory of THz interface physics, including interface formation with advanced materials, THz wave reflection and transmission at the interface, and band alignment and charge dynamics at the interface. Then we move to recent progresses in advanced materials from THz wave propagation to THz wave generation at the interface. In the THz wave propagation, we focus on the THz wave impedance-matching, Goos–Hänchen and Imbert–Fedorov shifts in THz region, interfacial modulation and interfacial sensing based on THz wave. In the THz wave generation, we summarize the ongoing coherent THz wave generation from van der Waals interfaces, multiferroic interfaces, and magnetic interfaces. The fascinating THz interface physics in advanced materials is promising and promoting novel THz functional devices for manipulating the propagation and generation of THz wave at the interfaces.