Accurate and affordable methods for predicting the underwater radiated noise of ships will facilitate the development of effective noise control techniques. The acoustic overlapping mesh (AOM) technique, which enables...
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Establishing and approaching the fundamental limit of orbital-angular-momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate t...
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Establishing and approaching the fundamental limit of orbital-angular-momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate the fundamental limit in terms of independent scattering channels (or the degrees of freedom of scattered fields) through angular-spectral analysis, in conjunction with a rigorous Green’s function method. The scattering-channel limit is universal for arbitrary spatial-mode multiplexing, which is launched by a planar electromagnetic device, such as antenna, metasurface, etc., with a predefined physical size. As a proof of concept, we demonstrate both theoretically and experimentally the limit by a phase-only metasurface hologram that transforms orthogonal OAM modes to plane-wave modes scattered at critically separated angular-spectral regions. Particularly, a minimax optimization algorithm is applied to suppress angular-spectrum aliasing, achieving good performances in both full-wave simulation and experimental measurement at microwave frequencies. This work offers a theoretical upper bound and corresponding approach route for engineering designs of OAM multiplexing.
It has been proved that fire accident frequency in nuclear power plants is higher than we thought it was and fire accidents have a huge significant impact on the safety of nuclear power, so it is extremely necessary t...
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Combat search and rescue（CSAR） is a significant part of joint combat operation. The isolated personnel in hostile territory is of great value to both sides. For the sake of extremely high cost and massive consumptio...
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Combat search and rescue（CSAR） is a significant part of joint combat operation. The isolated personnel in hostile territory is of great value to both sides. For the sake of extremely high cost and massive consumption of time in military exercises, virtual reality is a preferred way to conduct the experiment. Mixed reality, known as MR, allows users to interact with the virtual objects, as well as the real objects. With MR devices, commanders get a better awareness of both virtual combat and real environment. Agent-based modelling is a relatively new approach to modelling systems composed of interacting objects. By analyzing the decision-making process of agents, codes are written to drive the simulation. Finally, the whole system is applied to HoloLens to provide a holographic demonstration.
Hydrogen combustion or detonation happened in the containment within the process of the small reactor severe accident may threaten the integrity of the containment. In this paper, based on systemic design of the Small...
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Effects of different age groups and different external loading distribution on lower extremity muscle activation during obstacle crossing tasks were tested in this study. Four young participants and five healthy senio...
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