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| 2. |
- Ergun, R. E., et al.
(författare)
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Observations of Particle Acceleration in Magnetic Reconnection-driven Turbulence
- 2020
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Ingår i: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 898:2
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Tidskriftsartikel (refereegranskat)abstract
- The Magnetospheric Multiscale Mission observes, in detail, charged particle heating and substantial nonthermal acceleration in a region of strong turbulence (vertical bar delta B vertical bar/vertical bar B vertical bar similar to 1, where B is the magnetic field) that surrounds a magnetic reconnection X-line. Magnetic reconnection enables magnetic field annihilation in a volume that far exceeds that of the diffusion region. The formidable magnetic field annihilation breaks into strong, intermittent turbulence with magnetic field energy as the driver. The strong, intermittent turbulence appears to generate the necessary conditions for nonthermal acceleration. It creates intense, localized currents (J) and unusually large-amplitude electric fields (E). The combination of turbulence-generated E and J results in a significant net positive mean of J center dot E, which signifies particle energization. Ion and electron heating rates are such that they experience a fourfold increase from their initial temperature. Importantly, the strong turbulence also generates magnetic holes or depletions in vertical bar B vertical bar that can trap particles. Trapping considerably increases the dwell time of a subset of particles in the turbulent region, which results in significant nonthermal particle acceleration. The direct observation of strong turbulence that is enabled by magnetic reconnection with nonthermal particle acceleration has far-reaching implications, since turbulence in plasmas is pervasive and may occupy significant volumes of the interstellar medium and intergalactic space. For example, strong turbulence from magnetic field annihilation in the supernova nebulae may dominate large volumes. As such, this observed energization process could plausibly contribute to the supply and development of the cosmic-ray spectrum.
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| 3. |
- Langer, Judith, et al.
(författare)
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Present and Future of Surface-Enhanced Raman Scattering
- 2020
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 14:1, s. 28-117
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Forskningsöversikt (refereegranskat)abstract
- The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article. ©
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| 4. |
- Monje Real, Alberto, et al.
(författare)
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Holey Glide-Symmetric Filters for 5G at Millimeter-Wave Frequencies
- 2020
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Ingår i: IEEE Microwave and Wireless Components Letters. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1531-1309 .- 1558-1764. ; 30:1, s. 31-34
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Tidskriftsartikel (refereegranskat)abstract
- A fully metallic glide-symmetric waveguide filter with transmission in Ka -band and attenuation at its second harmonic is proposed. The filter is low-loss and cost-effective for high frequencies, and it can be easily integrated with an antenna. Glide symmetry and the possibility of breaking this symmetry provide an additional degree of freedom for passband and stopband control. A new kind of 2-D glide symmetry, referred to as braided glide symmetry, is presented, showing an increased attenuation per unit cell
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| 5. |
- Monje Real, Alberto, et al.
(författare)
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Holey Glide-Symmetric Waveguide Filters for 5G Communication Systems at Millimetre Wave Frequencies
- 2020
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Ingår i: 2020 14TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP 2020). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a holey, fully-metallic, glide symmetric waveguide filter. This solution is low-loss, cost-effective, robust and suitable for applications at millimetre wave frequencies (e.g. Ka band). We also explore here the possibility to break the glide symmetry as an additional degree of freedom to control the pass and stopbands. Finally, a denser kind of glide symmetry, named braided glide symmetry, is introduced to enhance the attenuation per unit cell.
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