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- Huang, Zeyu, et al.
(författare)
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Optimal Phasors for Wideband RIS Transmissions
- 2023
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Ingår i: 2023 IEEE Conference on Antenna Measurements and Applications, CAMA 2023. - 2474-1760 .- 2643-6795. - 9798350323047 ; , s. 250-254
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Konferensbidrag (refereegranskat)abstract
- Configuring reconfigurable intelligent surfaces (RISs) based on a practical RIS model is a fundamental problem in RIS-assisted wireless transmission. In this work, we propose a concept named optimal phasor (OP), a latent quantity that can considerably help the practical model-based RIS configuration. Under such a concept, we can design versatile algorithms that are applicable to different RIS models. As an example, we formulate the optimization problem of frequency selectivity reduction and develop an OP-based algorithm, allowing us to reach a remarkable performance based on the practical one-bit RIS model.
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- Iwan, Bianca, et al.
(författare)
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Explosion, ion acceleration and molecular fragmentation of methane clusters in the pulsed beam of a free-electron laser
- 2012
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 86:3, s. 033201-
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Tidskriftsartikel (refereegranskat)abstract
- X-ray lasers offer new possibilities for creating and probing extreme states of matter. We used intense and short x-ray pulses from the FLASH soft x-ray laser to trigger the explosions of CH4 and CD4 molecules and their clusters. The results show that the explosion dynamics depends on cluster size and indicate a transition from Coulomb explosion to hydrodynamic expansion in larger clusters. The explosion of CH4 and CD4 clusters shows a strong isotope effect: The heavier deuterons acquire higher kinetic energies than the lighter protons. This may be due to an extended inertial confinement of deuterons vs. protons near a rapidly charging cluster core during exposure.
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