344 research outputs found
Downlink and Uplink Intelligent Reflecting Surface Aided Networks: NOMA and OMA
Intelligent reflecting surfaces (IRSs) are envisioned to provide
reconfigurable wireless environments for future communication networks. In this
paper, both downlink and uplink IRS-aided non-orthogonal multiple access (NOMA)
and orthogonal multiple access (OMA) networks are studied, in which an IRS is
deployed to enhance the coverage by assisting a cell-edge user device (UD) to
communicate with the base station (BS). To characterize system performance, new
channel statistics of the BS-IRS-UD link with Nakagami- fading are
investigated. For each scenario, the closed-form expressions for the outage
probability and ergodic rate are derived. To gain further insight, the
diversity order and high signal-to-noise ratio (SNR) slope for each scenario
are obtained according to asymptotic approximations in the high-SNR regime. It
is demonstrated that the diversity order is affected by the number of IRS
reflecting elements and Nakagami fading parameters, but the high-SNR slope is
not related to these parameters. Simulation results validate our analysis and
reveal the superiority of the IRS over the full-duplex decode-and-forward
relay.Comment: Accepted for publication in the IEEE Transactions on Wireless
Communication
Establishment and Evaluation of a Loop-Mediated Isothermal Amplification Assay for Detection of Raccoon Dog in Meat Mixtures
Raccoon dog (Nyctereutes procyonoides) is an economically important animal used for fur production, but consuming its meat is injurious to human health. Currently, no rapid and sensitive method for detecting raccoon dog meat in meat mixtures is available. In this study, we developed an easily applicable, rapid, and economically feasible method for identifying the presence of raccoon dog in meat mixtures based on loop-mediated isothermal amplification (LAMP). Four sets of LAMP primers were tested at different temperatures, and the primers that worked best at 62°C (set 2) were determined. In the LAMP assay, there was no cross-reactivity with the meat procured from other species of animals and the detection limit of DNA concentration was 0.1 pg·μL−1, slightly higher than TaqMan real-time PCR (0.01 pg·μL−1), but sensitivity of 0.1 pg·μL−1 complies with most requirements of routine analysis. Moreover, by the LAMP method, the meat mixtures containing more than 0.5% of the raccoon dog component were directly detected (without DNA extraction) in the supernatant isolated from the meat mixtures after performing repeated cycles of thawing and freezing of minced meat mixtures. Our results show that LAMP assay is a valuable, straightforward, and sensitive detection tool for identification of raccoon dog meat in mixtures
High-Throughput Screening of Transition Metal Single-Atom Catalysts for Nitrogen Reduction Reaction
The discovery of metals as catalytic centers for nitrogen reduction reactions
has stimulated great enthusiasm for single-atom catalysts. However, the poor
activity and low selectivity of available SACs are far away from the industrial
requirement. Through the high throughout first principles calculations, the
doping engineering can effectively regulate the NRR performance of b-Sb
monolayer. Especially, the origin of activated N2 is revealed from the
perspective of the electronic structure of the active center. Among the 24
transition metal dopants, Re@Sb and Tc@Sb showed the best NRR catalytic
performance with a low limiting potential. The Re@Sb and Tc@Sb also could
significantly inhibit HER and achieve a high theoretical Faradaic efficiency of
100%. Our findings not only accelerate discovery of catalysts for ammonia
synthesis but also contribute to further elucidate the structure-performance
correlations
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