| 1. |
- Chen, Kai, et al.
(författare)
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Room-temperature multiferroic properties in NiBi2O4
- 2010
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Ingår i: Europhysics letters. - : European Physical Society. - 0295-5075 .- 1286-4854. ; 89:2
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Tidskriftsartikel (refereegranskat)abstract
- Magnetism and ferroelectricity at room temperature are observed in the NiBi2O4 ceramics. Both the time reversal and the inversion symmetry of the structure (space group F-43m) are broken. The saturation magnetization is 0.028 emu/g and the saturation polarization 2P(s) similar to 4.0 mu C/cm(2). NiBi2O4 also shows other room-temperature multiferroic properties, e. g. the piezoelectric coefficient (d(33)), the polarized dielectric character, the magneto-dielectric response and the magnetoelectric effect. Copyright (C) EPLA, 2010
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| 2. |
- Chiaraviglio, Luca, et al.
(författare)
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5G in rural and low-income areas : Are we ready?
- 2016
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Ingår i: PROCEEDINGS OF THE 2016 ITU KALEIDOSCOPE ACADEMIC CONFERENCE - ICTS FOR A SUSTAINABLE WORLD (ITU WT). - Piscataway, NJ : IEEE. - 9789261204518 ; , s. 99-106
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Konferensbidrag (refereegranskat)abstract
- Current trends in telecommunication networks foresee the adoption of the,fifth generation (5G) of wireless networks in the near fixture. However; a large number of people are living without coverage and connectivity. To face this issue, we consider the possibility of deploying 5G networks in rural and low-income zones. After detailing the current state-of-the-art, we consider the main challenges that need to be faced. Moreover; we define the main pillars to follow in order to deploy 5G networks in such zones, as well as a proposal of a future network architecture.
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| 3. |
- Chiaraviglio, Luca, et al.
(författare)
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Bringing 5G into Rural and Low-Income Areas : Is It Feasible?
- 2017
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Ingår i: IEEE Communications Standards Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 2471-2825. ; 1:3, s. 50-57
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, at least two billion people are experiencing a complete lack of wireless cellular network coverage. These users live in rural areas and low-income regions, where network operators are not keen to invest, mainly due to high capital expenditure and operational expenditure costs, as well as the scarcity of electricity from the grid. We tackle this challenge by proposing a 5G network explicitly designed to serve rural and low-income areas. Our solution investigates the possibility of mounting remote radio heads on top of unmanned aerial vehicles, as well as large cells (LCs) to increase the coverage range. In addition, 5G nodes are powered by solar panels and batteries. Preliminary results, obtained over three representative case studies located in Italy, Cook Islands, and Zimbabwe, show that providing connectivity in rural and low-income areas by means of the proposed 5G architecture is feasible. At the same time, we also show that the monthly subscription fee paid by the users can be kept sufficiently low, that is, less than €1/month in low-income areas, and around €11/month in rural regions.
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| 4. |
- Du, Jinfeng, et al.
(författare)
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Design of isotropic orthogonal transform algorithm-based multicarrier systems with blind channel estimation
- 2012
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Ingår i: IET Communications. - : Institution of Engineering and Technology. - 1751-8628 .- 1751-8636. ; 6:16, s. 2695-2704
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Tidskriftsartikel (refereegranskat)abstract
- Orthogonal frequency division multiplexing (OFDM) technique has gained increasing popularity in both wired andwireless communication systems. However, in the conventional OFDM systems the insertion of a cyclic prefix (CP) and the transmission of periodic training sequences for purpose of channel estimation decrease the system’s spectral efficiency. As an alternative to OFDM, isotropic orthogonal transform algorithm (IOTA)-based multicarrier system adopts a proper pulse shaping with good time and frequency localisation properties to avoid interference and maintain orthogonality in real field among sub-carriers without the use of CP. In this study, the authors propose linearly precoded IOTA-based multicarrier systems to achieve blind channel estimation by utilising the structure of auto-correlation and cross-correlation matrices introduced by precoding. The results show that the proposed IOTA-based multicarrier systems achieve better power and spectral efficiency compared with the conventional OFDM systems.
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| 5. |
- Fu, Xianbiao, et al.
(författare)
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High-Entropy Alloy Nanosheets for Fine-Tuning Hydrogen Evolution
- 2022
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 12:19, s. 11955-11959
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Tidskriftsartikel (refereegranskat)abstract
- The electrolysis of water is promising for hydrogen production. The development of high-performance and low-cost hydrogen evolution reaction (HER) electrocatalysts is particularly important for the wide application of water electrolyzers. Tuning the hydrogen binding energy (HBE) of materials is an effective way to optimize the HER electrocatalysts, particularly for applications in an acidic environment. Here, we report the discovery of a Pt-free combination, PdMoGaInNi, which has the HBE optimum, via computer-facilitated screening. As the exploratory example of the two-dimensional high-entropy alloy (HEA) for HER, the PdMoGaInNi HEA nanosheets were synthesized to realize the predicted Pt-free combination with optimal HBE. The PdMoGaInNi HEA nanosheets exhibit a high HER activity with low overpotentials of 13 mV at 10 mA cm-2, outperforming commercial Pd/C and Pt/C catalysts. Given the high entropy, lattice distortion, and sluggish diffusion effects of HEA, the PdMoGaInNi shows great long-term durability for at least 200 h in a proton exchange membrane water electrolyzer.
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| 6. |
- Jiang, Yan, et al.
(författare)
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Negligible-Pb-Waste and Upscalable Perovskite Deposition Technology for High-Operational-Stability Perovskite Solar Modules
- 2019
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Ingår i: Advanced Energy Materials. - : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 9:13
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Tidskriftsartikel (refereegranskat)abstract
- An upscalable perovskite film deposition method combining raster ultrasonic spray coating and chemical vapor deposition is reported. This method overcomes the coating size limitation of the existing stationary spray, single-pass spray, and spin-coating methods. In contrast with the spin-coating method (>90% Pb waste), negligible Pb waste during PbI2 deposition makes this method more environmentally friendly. Outstanding film uniformity across the entire area of 5 cm x 5 cm is confirmed by both large-area compatible characterization methods (electroluminescence and scattered light imaging) and local characterization methods (atomic force microscopy, scanning electron microscopy, photoluminescence mapping, UV-vis, and X-ray diffraction measurements on multiple sample locations), resulting in low solar cell performance decrease upon increasing device area. With the FAPb(I0.85Br0.15)(3) (FA = formamidinium) perovskite layer deposited by this method, champion solar modules show a power conversion efficiency of 14.7% on an active area of 12.0 cm(2) and an outstanding shelf stability (only 3.6% relative power conversion efficiency decay after 3600 h aging). Under continuous operation (1 sun light illumination, maximum power point condition, dry N-2 atmosphere with <5% relative humidity, no encapsulation), the devices show high light-soaking stability corresponding to an average T-80 lifetime of 535 h on the small-area solar cells and 388 h on the solar module.
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| 7. |
- Li, Jie, et al.
(författare)
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Introduction to the Special Section on Big Data and Artificial Intelligence for Network Technologies
- 2020
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Ingår i: IEEE Transactions on Network Science and Engineering. - : IEEE. - 2327-4697. ; 7:1, s. 1-2
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The papers in this special section examines the deployment of Big Data and artificial intelligence for network technologies. The eneration of huge amounts of data, called big data, is creating the need for efficient tools to manage those data. Artificial intelligence (AI) has become the powerful tool in dealing with big data with recent breakthroughs at multiple fronts in machine learning, including deep learning. Meanwhile, information networks are becoming larger and more complicated, generating a huge amount of runtime statistics data such as traffic load, resource usages. The emerging big data and AI technologies may include a bunch of new requirements, applications and scenarios such as e-health, Intelligent Transportation Systems (ITS), Industrial Internet of Things (IIoT), and smart cities in the term of computing networks. The big data and AI driven network technologies also provide an unprecedented patient to discover new features, to characterize user demands and system capabilities in network resource assignment, security and privacy, system architecture, modeling and applications, which needs more explorations. The focus of this special section is to address the big data and artificial intelligence for network technologies. We appreciate contributions to this special section and the valuable and extensive efforts of the reviewers. The topics of this special section range from big data and AI algorithms, models, architecture for networks and systems to network architecture.
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| 8. |
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| 9. |
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| 10. |
- Xiao, Pei, et al.
(författare)
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Iterative Multi-User Detection and Decoding for DS-CDMA System with Space-Time Linear Dispersion
- 2009
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Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 58:5, s. 2343-2353
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers a Q-ary orthogonal DS-CDMA system with high rate space-time linear dispersion codes (LDC) in time-varying Rayleigh fading MIMO channels. We propose a joint multi-user detection, LDC decoding, Q-ary demodulation and channel decoding algorithm and apply turbo processing principle to improve the system performance in an iterative fashion. The proposed iterative scheme demonstrates faster convergence and superior performance (especially at low SNRs) compared to the V-BLAST based DS-CDMA system, and is shown to approach the single-user performance bound. The gain is more significant when the LDC decoding and symbol demodulation is assisted by a decision-directed multi-user detection technique. We also show that the CDMA system is able to exploit the time diversity offered by the LDCs in fast fading channels.
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